Alexandros Sfakianakis
Anapafseos 5 . Agios Nikolaos
Crete.Greece.72100
2841026182
Anapafseos 5 . Agios Nikolaos
Crete.Greece.72100
2841026182
6948891480
Πέμπτη 15 Δεκεμβρίου 2016
Emergence of electronic cigarette use in US adolescents and the link to traditional cigarette use
Source:Addictive Behaviors, Volume 67
Author(s): Stephanie T. Lanza, Michael A. Russell, Jessica L. Braymiller
BackgroundElectronic cigarettes (e-cigarettes) are increasingly used by US adolescents and may be a gateway to traditional cigarette use. We examine rates of both products by age and examine differences in age-varying rates by sex and race/ethnicity.MethodsData are from the 2014 National Youth Tobacco Survey, a national sample of US middle and high school students (n=22.007); students ages 11–19 were included. Past 30-day e-cigarette and traditional cigarette use were examined as a function of age; sex and race/ethnicity were included as moderators. The age-varying association between e-cigarette and traditional cigarette use was also examined.ResultsRates of e-cigarette use increase faster than traditional cigarette use from ages 13–16. Compared to females, males had higher rates of e-cigarette use from ages 14–17.5 and traditional cigarette use from ages 15–18. Between ages 12–14, more Hispanic adolescents used e-cigarettes compared to White or Black adolescents; after age 14 Hispanics and Whites reported similar rates, peaking at twice the rate for Blacks. Hispanic adolescents report greater traditional cigarette use versus Whites between ages 12–13, but lower rates between ages 15–18. E-cigarette use was strongly associated with traditional cigarette use, particularly during early adolescence [OR>40 before age 12].ConclusionsYoung Hispanic adolescents are at elevated risk for use of e-cigarettes and traditional cigarettes during early adolescence. During early adolescence, youth using e-cigarettes are more likely to smoke traditional cigarettes compared to youth not using e-cigarettes. The study of age-varying effects holds promise for advancing understanding of disparities in health risk behaviors.
http://ift.tt/2hMZiYl
Racial differences in the link between alcohol expectancies and adolescent drinking
Source:Addictive Behaviors, Volume 67
Author(s): Devin E. Banks, Tamika C.B. Zapolski
IntroductionAlcohol expectancies are important determinants and predictors of adolescent alcohol use. Research with African Americans has shown that the endorsement of positive alcohol expectancies differs from that of Whites during childhood and predicts different alcohol outcomes during young adulthood. However, limited research has explored racial differences in the relationship between expectancy endorsement and alcohol use in school-aged adolescents. The current study examines the effect of White or African American race on the relationship between positive alcohol expectancies and alcohol use.MethodsParticipants were 104 adolescents ages 12–18 who identified as either non-Hispanic White or non-Hispanic African American. Participants completed self-report measures of alcohol consumption and positive social alcohol expectancies.ResultsPreliminary analyses revealed no racial differences in alcohol expectancies or consumption. However, race moderated the relationship between alcohol expectancies and alcohol use such that more positive expectancies predicted alcohol use among White youth, but not African American youth.ConclusionsThese results suggest that alcohol expectancies, which were thought to be important mediators of the relationship between social and personality factors and adolescent alcohol use may not be as impactful for African Americans. Future research should focus on identifying factors posing unique risk for alcohol consumption in this population.
http://ift.tt/2gHJm4L
Aberrant default mode network homogeneity in patients with first-episode treatment-naive melancholic depression
Source:International Journal of Psychophysiology
Author(s): Xilong Cui, Wenbin Guo, Yi Wang, Tian-xiao Yang, Xin-hua Yang, Yefei Wang, Jingbo Gong, Changlian Tan, Guangrong Xie
BackgroundMelancholic depression is a relatively homogenous subtype of major depressive disorders (MDD). The condition has several endogenous symptoms and represents strong biological components. However, its specific neurobiological mechanisms remain unknown. Previous neuroimaging findings indicated that default mode network (DMN) is closely related to MDD. The present study examined the network homogeneity (NH) of the DMN in patients with melancholic MDD.MethodsA total of 33 first-episode, treatment-naive melancholic MDD patients and 32 healthy controls underwent a resting-state functional magnetic resonance imaging scan. The data were analyzed using the NH method.ResultsCompared with healthy controls, patients with melancholic MDD showed low NH values in the right middle temporal gyrus and temporal pole (MTG/TP). The abnormal NH of this region and clinical characteristics were not correlated.ConclusionAbnormal NH pattern of DMN exists in patients with melancholic MDD. This feature may be part of the pathophysiological basis of this disorder.
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Photoinactivation of single and mixed biofilms of Candida albicans and non-albicans Candida species using Phorodithazine®
Source:Photodiagnosis and Photodynamic Therapy
Author(s): Juliana Cabrini Carmello, Fernanda Alves, Ewerton Garcia de Oliveira Mima, Janaina Habib Jorge, Vanderlei Salvador Bagnato, Ana Cláudia Pavarina
This study evaluated the effectiveness of antimicrobial photodynamic therapy (aPDT) mediated by Photodithazine® (PDZ) formulated in hydrogel, in the inactivation of mono and duo-species biofilms of Candida albicans, Candida glabrata and Candida tropicalis. Standardized suspensions of each strain were prepared and after biofilm formation, mono-species were treated with 150 and 175mg/L of PDZ for 20minutes (pre-irradiation time), and exposed to LED light at a dose of 37.5J/cm2 (660nm). The duo-species biofilms (C. albicans+C. glabrata and C. albicans+C. tropicalis) were treated with 150mg/L of PDZ and light. Additional samples were treated with PDZ or light only, and the control did not receive any treatment. Next, microbiological evaluation was performed by spreading the cells on Sabouraud Dextrose Agar and CHROMagar Candida for colony forming units (CFU/mL). Moreover, the total biomass of biofilm was verified using the crystal violet staining assay (CV). The data were submitted to ANOVA and Tukey post-hoc (α=0.05). The use of PDZ 150mg/L promoted a reduction of 1.0, 1.2, 1.5 log10 in the viability of C. glabrata, C. albicans and C. tropicalis, respectively. The same concentration reduced in 1.0 log10 the viability of each species grown as duo-species biofilms. The crystal violet assay showed that the use of 150mg/L reduced 24.4%, 39.2% and 43.7% of the total biomass of C. albicans, C. tropicalis and C. glabrata, respectively. aPDT did not reduce the total biomass to the duo-species biofilms. Thus, PDZ-mediated aPDT was more effective in the inactivation of mono-species biofilms of Candida spp. compared with duo-species biofilm.
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Antrodia salmonea induces G2 cell-cycle arrest in human triple-negative breast cancer (MDA-MB-231) cells and suppresses tumor growth in athymic nude mice
Publication date: 20 January 2017
Source:Journal of Ethnopharmacology, Volume 196
Author(s): Chia-Ting Chang, You-Cheng Hseu, Varadharajan Thiyagarajan, Hui-Chi Huang, Li-Sung Hsu, Pei-Jane Huang, Jer-Yuh Liu, Jiunn-Wang Liao, Hsin-Ling Yang
Ethnopharmacological relevanceAntrodia salmonea (AS), is a well-known folk medicinal mushroom in Taiwan, has been reported to exhibit anti-oxidant, anti-angiogenic, and anti-inflammatory effects.Materials and methodsIn the present study, we examined the effects of AS on cell-cycle arrest in vitro in MDA-MB-231 cells and on tumor regression in vivo using an athymic nude mice model.ResultsAS (0–200μg/mL) treatment significantly induced G2 cell-cycle arrest in MDA-MB-231 cells by reducing the levels of cyclin B1, cyclin A, cyclin E, and CDC2 proteins. In addition, N-acetylcysteine (NAC) pretreatment prevented AS induced G2 cell-cycle arrest, indicating that ROS accumulation and subsequent cell cycle arrest might be a major mechanism of AS-induced cytotoxicity. Further, AS treatment decreased COX-2 expression and induced PARP cleavage was significantly reversed by NAC pretreatment in MDA-MB-231 cells. The in vivo study results revealed that AS treatment was effective in terms of delaying the tumor incidence and reducing the tumor growth in MDA-MB-231-xenografted nude mice. TUNEL assay, immunohistochemical staining and Western blotting confirmed that AS significantly modulated the xenografted tumor progression as demonstrated by induction of apoptosis, autophagy, and cell-cycle arrest.ConclusionOur data strongly suggest that Antrodia salmonea could be an anti-cancer agent for human breast cancer.
Graphical abstract
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A traditional Chinese formula composed of Chuanxiong Rhizoma and Gastrodiae Rhizoma (Da Chuanxiong Formula) suppresses inflammatory response in LPS -induced RAW 264.7 cells through inhibition of NF-κB pathway
Publication date: 20 January 2017
Source:Journal of Ethnopharmacology, Volume 196
Author(s): Zhi-Ke Liu, Chun-Fai Ng, Hoi-Ting Shiu, Hing-Lok Wong, Chun-Wai Wong, Kai-Kai Li, Jin-Fang Zhang, Ping-Kuen Lam, Wai-Sang Poon, Clara Bik-San Lau, Ping-Chung Leung, Chun-Hay Ko
Ethnopharmacological relevanceDa Chuanxiong Formula (DCXF) which origins from Jin Dynasty is a famous classical 2-herb Chinese medicinal prescription. It is composed of dried rhizomes of Ligusticum chuanxiong (Chuanxiong Rhizoma, CR) and Gastrodia elata (Gastrodiae Rhizoma, GR) at the ratio of 4:1 (w/w). It has been used to treat headache which is caused by wind pathogen and blood stasis for thousands of years in China.Aim of studyThe present study was performed to investigate the anti-inflammatory effect of DCXF and elucidate its underlying molecular mechanisms using LPS-stimulated RAW 264.7 cells.Materials and methodsThe anti-inflammatory effect of DCXF was evaluated using LPS-stimulated RAW 264.7 cells. Generation of nitric oxide (NO) and prostaglandin E2 (PGE2) were measured by the Griess colorimetric method and enzyme-linked immunosorbent assay (ELISA), respectively. The gene expressions of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) were detected by reverse transcription-polymerase chain reaction (RT-PCR). Furthermore, the effect of DCXF on NF-κB activation was measured by western blot assay.ResultsTreatment with DCXF significantly suppressed the productions of NO and PGE2 through inhibitions of iNOS and COX-2 expressions in LPS-stimulated RAW 264.7 cells. DCXF significantly decreased IκBα phosphorylation, inhibited p65 expression and reduced p-p65 level. These results suggested the anti-inflammatory effect of DCXF was associated with the reduction of inflammatory mediators through inhibition of NF-κB pathway.ConclusionsThese results indicated that DCXF inhibited inflammation in LPS-stimulated RAW 264.7 cells through inactivation of NF-κB pathway.
Graphical abstract
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Clinical efficacy of Rong-Yang-Jyh-Gan-Tang on patients with chronic hepatitis C: A double-blinded randomized placebo-controlled crossover study
Publication date: 20 January 2017
Source:Journal of Ethnopharmacology, Volume 196
Author(s): Fang-Pey Chen, Ching-Mao Chang, Ta-Peng Wu, Jen-Lin Yang, Yen-Ying Kung, Yi-Hsiang Huang, Chien-Wei Su, Keng-Hsin Lan, Shu-Chiung Chiang, Shinn-Jang Hwang
Ethnopharmacological relevanceTraditional Chinese medicine (TCM) has been widely used by the Chinese population for treatment of chronic hepatitis. However, the efficacy of TCM for patients with chronic hepatitis has not been confirmed, mostly due to the lack of available scientific parameters such as serum viral load to evaluate treatment response.Aim of the studyWe evaluated the efficacy of Rong-Yang-Jyh-Gan-Tang (RYJGT, composed of Long-Dan-Xie-Gan-Tang, Jia-Wei-Xia-Yao-San, Dan-Shen, and Hou-Po) on patients with chronic hepatitis C.Materials and methodsThirty-six patients with chronic hepatitis C who had no response to or had contraindications to interferon-ribavirin therapy were randomly allocated to receive RYJGT 15g/day or placebo for 12 weeks. After a 2-week washout period, patients were crossed over to receive placebo or RYJGT for another 12 weeks. Evaluation parameters included liver biochemistries, serum HCVRNA, side effects of RYJGT/placebo, and TCM symptoms.ResultsOf the patients who had 12-week RYJGT treatment, 51.7% had decreased serum HCVRNA levels, whereas only 25.8% patients had decreased levels in the placebo group (p=0.036). TCM patterns of "Damp-Heat" and "Liver Qi Depression" had significantly improved after RYJGT treatment in comparison with the placebo. Logistic analyses showed that RYJGT treatment, and pre-treatment values of TCM symptoms of "Damp-Heat" and "Liver Qi Depression", were statistically significant factors in predicting the decrease in serum HCVRNA.ConclusionChronic hepatitis C patients who received a 12-week RYJGT treatment had significantly higher HCVRNA decrease ratio, and improved TCM symptoms of "Damp-Heat" and "Liver Qi Depression", than those who received the placebo. Our results require further larger scale clinical trials.
Graphical abstract
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Predicting mortality of patients with cirrhosis admitted to medical intensive care unit: An experience of a single tertiary center
Publication date: Available online 15 December 2016
Source:Arab Journal of Gastroenterology
Author(s): Abdel-Naser Elzouki, Shireen Suliman, Rania Alhasan, Ali Abdullah, Muftah Othman, Ahmad Badi
Background and study aimsPrognosis for patients with cirrhosis admitted to a medical intensive care unit (MICU) is poor and no previous studies have been published from Qatar or other countries in the region to investigate this issue. The objective of this study was to assess the predictors for in-hospital mortality and admission of cirrhotic patients to MICU in a single tertiary hospital in Qatar.Patients and methodsAll adult cirrhotic MICU patients hospitalized from 2007 through 2012 to Hamad General Hospital-Qatar were included. We compared them to cirrhotic patients admitted to medical wards during same period of time. All data were recorded and analyzed with respect to demographic parameters, clinical features and laboratory as well as radiology characteristics on day one of admission to MICU. Cirrhosis diagnosis was established either with a liver biopsy or the combination of physical, laboratory and radiologic findings. Predictors of mortality were defined by logistic regression analysis.ResultsThe cohort comprised 109 cirrhotic MICU patients (86.2% males), and their mean age±SD was 51.6±11.5. MICU-cirrhotic patients had longer hospital stays than medical wards-cirrhotic patients (p=0.01). Admission with severe hepatic encephalopathy, upper gastrointestinal bleeding and SOFA (Sepsis Related Organ Failure Assessment) score were the independent predicting factors for MICU admission. Mortality was higher for the MICU-cirrhotic group than medical wards group (27 (24.8%) deaths vs. 12 (5.3%) deaths, respectively, p=0.001). In multivariate logistic regression analyses, older age>60years (p=0.04), APACH-II score (p=0.001) and MELD score (p=0.02) were independent predicting factors for overall mortality.ConclusionSevere hepatic encephalopathy, upper gastrointestinal bleeding and SOFA score predict MICU admission of cirrhotic patients. Among MICU cirrhotic patients, older age, APACH-II score and MELD score predict mortality.
http://ift.tt/2gPYwtE
Quality assurance in gastrointestinal endoscopy: An Egyptian experience
Publication date: Available online 15 December 2016
Source:Arab Journal of Gastroenterology
Author(s): Ahmed S. Gado, Basel A. Ebeid, Anthony T. Axon
Over the last four decades, gastrointestinal endoscopy has become of paramount importance to diagnose, treat and prevent diseases of the digestive tract. Practice variation, however, is likely to have an important effect on the effectiveness of endoscopy and can impair the delivery of high-quality endoscopic procedures. There have been increasing demands to assess the quality of service and track and improve patient outcomes. Quality assurance has paved its way into professional guidelines for physicians. Developing a modern endoscopy unit demands the institution of a quality assurance programme, continuous training and monitoring of service delivery. This article describes our experience in implementing a quality assurance programme in endoscopy in a secondary care government hospital in Egypt. The implementation of quality assurance and improvement programme can lead to dramatic improvements in the quality of endoscopic care and patient outcomes. Quality assurance and continual improvement can be applied in developing countries.
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Neural Progenitor Cells in Cerebral Cortex of Epilepsy Patients do not Originate from Astrocytes Expressing GLAST
Adult neurogenesis in human brain is known to occur in the hippocampus, the subventricular zone, and the striatum. Neural progenitor cells (NPCs) were reported in the cortex of epilepsy patients; however, their identity is not known. Since astrocytes were proposed as the source of neural progenitors in both healthy and diseased brain, we tested the hypothesis that NPCs in the epileptic cortex originate from reactive, alternatively, de-differentiated astrocytes that express glutamate aspartate transporter (GLAST). We assessed the capacity to form neurospheres and the differentiation potential of cells dissociated from fresh cortical tissue from patients who underwent surgical treatment for pharmacologically intractable epilepsy. Neurospheres were generated from 57% of cases (8/14). Upon differentiation, the neurosphere cells gave rise to neurons, oligodendrocytes, and astrocytes. Sorting of dissociated cells showed that only cells negative for GLAST formed neurospheres. In conclusion, we show that cells with neural stem cell properties are present in brain cortex of epilepsy patients, and that these cells are not GLAST-positive astrocytes.
http://ift.tt/2hBDXOK
Developing shared understandings of recovery and care: a qualitative study of women with eating disorders who resist therapeutic care
Abstract
Background
This paper explores the differing perspectives of recovery and care of people with disordered eating. We consider the views of those who have not sought help for their disordered eating, or who have been given a diagnosis but have not engaged with health care services. Our aim is to demonstrate the importance of the cultural context of care and how this might shape people's perspectives of recovery and openness to receiving professional care.
Method
This study utilised a mixed methods approach of ethnographic fieldwork and psychological evaluation with 28 women from Adelaide, South Australia. Semi-structured interviews, observations, field notes and the Eating Disorder Examination were the primary forms of data collection. Data was analysed using thematic analysis.
Results & Discussion
Participants in our study described how their disordered eating afforded them safety and were consistent with cultural values concerning healthy eating and gendered bodies. Disordered eating was viewed as a form of self-care, in which people protect and 'take care' of themselves. These subjectively experienced understandings of care underlie eating disorder behaviours and provide an obstacle in seeking any form of treatment that might lead to recovery.
Conclusion
A shared understanding between patients and health professionals about the function of the eating disorder may avoid conflict and provide a pathway to treatment. These results suggest the construction of care by patients should not be taken for granted in therapeutic guidelines. A discussion considering how disordered eating practices are embedded in a matrix of care, health, eating and body practices may enhance the therapeutic relationship.
http://ift.tt/2hqz7Wc
Label-free electrical sensing of bacteria in eye wash samples: A step towards point-of-care detection of pathogens in patients with infectious keratitis
Source:Biosensors and Bioelectronics, Volume 91
Author(s): Hardik J. Pandya, Manoj Kumar Kanakasabapathy, Saloni Verma, Manjyot Kaur Chug, Adnan Memic, Mihaela Gadjeva, Hadi Shafiee
The diagnosis of keratitis is based on visual exam, tissue cytology, and standard microbial culturing to determine the type of the infectious pathogen. To prescribe appropriate therapy, it is important to distinguish between bacterial, fungal, and viral keratitis, as the treatments are quite different. Diagnosis of the causative organism has a substantial prognostic importance. Further, timely knowledge of the nature of the pathogen is also critical to adapt therapy in patients unresponsive to empiric treatment options, which occurs in 10% of all cases. Currently, the identification of the nature of the pathogen that causes keratitis is achieved via microbial culture screening, which is laboratory-based, expensive, and time-consuming. The most frequent pathogens that cause the corneal ulcers are P. aeruginosa and S. aureus. Here, we report a microchip for rapid (<1h) detection of P. aeruginosa (6294), S. aureus(LAC), through on-chip electrical sensing of bacterial lysate. We evaluated the microchip with spiked samples of PBS with bacteria concentration between 101 to 108 CFU/mL. The least diluted bacteria concentration in bacteria-spiked samples with statistically significant impedance change was 10 CFU/mL. We further validated our assay by comparing our microchip results with the standard culture-based methods using eye washes obtained from 13 infected mice.
http://ift.tt/2h3Xbvi
Competitive RNA-RNA hybridization-based integrated nanostructured-disposable electrode for highly sensitive determination of miRNAs in cancer cells
Publication date: 15 May 2017
Source:Biosensors and Bioelectronics, Volume 91
Author(s): M. Zouari, S. Campuzano, J.M. Pingarrón, N. Raouafi
A new method for the detection of miRNAs making use of a competitive RNA/RNA hybridization configuration is described in this work. A biotinylated miRNA (biotin-miRNA) of identical sequence to that of the target miRNA is mixed with the samples to be analyzed allowing competition to be accomplished with the target miRNA for a thiolated RNA probe assembled onto a gold nanoparticles (AuNPs) modified screen-printed electrode. After labeling the hybridized biotin-miRNA with streptavidin-HRP conjugates, amperometric detection at −0.20V was carried out using the H2O2/hydroquinone (HQ) system. The decrease in the amperometric response was proportional to the concentration of model target miRNA-21 in the 100 fM to 25.0 pM range. The integrated sensor provided a very low detection limit (25 fM, 0.25 attomol in 10μL sample) for miRNA-21 without any amplification step, a complete discrimination against single nucleotide mismatched sequences under practical conditions and high storage stability. The usefulness of the developed method was demonstrated by determining the endogenous levels of the mature target miRNA in total RNA (RNAt) extracted from cancerous and non-cancerous cells.
Graphical abstract
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Detection and differentiation of influenza viruses with glycan-functionalized gold nanoparticles
Source:Biosensors and Bioelectronics, Volume 91
Author(s): Longtang Zheng, Jinhua Wei, Xun Lv, Yuhai Bi, Peixing Wu, Zhenxing Zhang, Pengfei Wang, Ruichen Liu, Jingwen Jiang, Haolong Cong, Jingnan Liang, Wenwen Chen, Hongzhi Cao, Wenjun Liu, George F. Gao, Yuguang Du, Xingyu Jiang, Xuebing Li
Accurate diagnosis of influenza viruses is difficult and generally requires a complex process because of viral diversity and rapid mutability. In this study, we report a simple and rapid strategy for the detection and differentiation of influenza viruses using glycan-functionalized gold nanoparticles (gGNPs). This method is based on the aggregation of gGNP probes on the viral surface, which is mediated by the specific binding of the virus to the glycans. Using a set of gGNPs bearing different glycan structures, fourteen influenza virus strains, including the major subtypes currently circulating in human and avian populations, were readily differentiated from each other and from a human respiratory syncytial virus in a single-step colorimetric procedure. The results presented here demonstrate the potential of this gGNP-based system in the development of convenient and portable sensors for the clinical diagnosis and surveillance of influenza viruses.
http://ift.tt/2gMRiqj
Uncertainty characterization in the retrieval of an atmospheric point release
Source:Atmospheric Environment, Volume 152
Author(s): Sarvesh Kumar Singh, Pramod Kumar, Grégory Turbelin, Raj Rani
The study proposes a methodology in a recent inversion technique, called as Renormalization, to characterize the uncertainties in the reconstruction of a point source. The estimates are derived for measuring the inversion error, the degree of model fit towards measurements (model determination coefficient) and the confidence intervals for the retrieved point source parameters (mainly, location and strength). The inversion error is reflected through an angular estimate which measures the deviation between the measured and predicted concentrations. The uncertainty estimation methodology is evaluated for point source reconstruction studies, using real measurements from two field experiments, known as Fusion Field Trials 2007 (FFT07) in flat terrain and Mock Urban Setting Test (MUST) in urban like terrain. In FFT07 and MUST experiments, the point source location is retrieved with an average Euclidean distance of 22 m and 15 m respectively. The source strength is retrieved, on average, within a factor of 1.5 in both the datasets. The inversion error is observed as 24o and 21o in FFT07 and MUST experiment, respectively. The 95% confidence interval estimates show that the uncertainty in the retrieved parameters is relatively large in approximately 50% FFT07 and 30% MUST trials in spite of their closeness towards true source parameters. For a comparative analysis, the interval estimates are also compared with a more general method of uncertainty estimation, Residual Bootstrap Sampling. In most of the trials, we observed that the intervals estimates with the present method are comparable (within 10–20% variations) to bootstrap estimates. The proposed methodology provides near accurate and computationally efficient uncertainty estimates in comparison to the methods based on Hessian and sampling procedures.
http://ift.tt/2hRm5OG
Editorial board
Source:Atmospheric Environment, Volume 150
http://ift.tt/2gOliAr
Effect of tillage and water management on GHG emissions from Mediterranean rice growing ecosystems
Source:Atmospheric Environment, Volume 150
Author(s): David Fangueiro, Daniel Becerra, Ángel Albarrán, David Peña, Javier Sanchez-Llerena, José Manuel Rato-Nunes, Antonio López-Piñeiro
Paddy rice fields are an important source of greenhouse gases (GHG), especially methane. In the present work, we assessed the impact on GHG emissions of two main parameters of rice production: aerobic rice production was compared with traditional flooded rice production and conventional tillage (CT) was compared with short-term and long-term no-tillage (NT) management. A field experiment was performed over three years and the GHG emissions were measured during each year. Five treatments (3 replicates) were considered: NTS7: no-tillage over seven years and sprinkler irrigation; NTS: no-tillage and sprinkler irrigation; CTS: conventional tillage and sprinkler irrigation; NTF: no-tillage and flooding; CTF: conventional tillage and flooding. The use of sprinkler irrigation rather than flooding led to decreases in nitrous oxide and methane emissions of ∼40% and more than 99%, respectively, over the 3-year experiment. The use of sprinkler irrigation compared with flooded irrigation reduced the global warming potential (GWP) about 40% and 36% in no-tillage and conventional tillage treatments, respectively. Treatment NTF decreased CH4 emissions, relative to CTF, by ∼60% over three years but the effect of NT on N2O emissions was not clear: a decrease or no effect was mostly observed in the NT treatments, relative to CT. A decrease of ∼40% in the total GHG emissions was observed in the NT treatments, relative to CT. No or small differences between NTS and NTS7 in terms of gaseous emissions were found. The short-term no-tillage and sprinkler irrigated treatment (NTS) gave lower yields than CTF in 2011 and 2012, but reached similar yields in the third year (NTS 8229 kg ha−1;CTF 8926 kg ha−1), with average savings of 75% of the total amount of water applied in CTF. The NTS7 data showed that high yields (reaching 9805 kg ha−1 in 2012) and water savings are sustainable in the long term. Considering the yield-scaled GWP of the emissions, NT gave a decrease of up to 42%, relative to CT. However, the effect of water management on yield-scaled GWP depended on the soil management: yield-scaled GWP was higher with flooding when NT was used and lower when tillage was used. It can be concluded that, for aerobic rice production, NT is an efficient strategy to minimize GHG emissions while maintaining high levels of production.
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The anti-tumor effects of the recombinant toxin protein rLj-RGD3 from Lampetra japonica on pancreatic carcinoma Panc-1 cells in nude mice
Source:Peptides
Author(s): Yue Wang, Yuanyuan Zheng, Zuoyu Tu, Yongguo Dai, Hong Xu, Li Lv, Jihong Wang
Recombinant Lampetra japonica RGD peptide (rLj-RGD3) is a soluble toxin protein with three RGD (Arg-Gly-Asp) motifs and a molecular weight of 13.5kDa. The aim of this study was to investigate the effects and mechanisms of rLj-RGD3 on tumor growth and survival in pancreatic carcinoma Panc-1 cell-bearing mice. A Panc-1 human pancreatic carcinoma-bearing nude mouse model was successfully generated, and the animals were treated with different doses of rLj-RGD3 for 3 weeks. The volume and weight of the subcutaneous tumors, the survival of the nude mice, histopathological changes, the intratumoral MVD, the number of apoptotic Panc-1 cells, and apoptosis-related proteins and gene expressions were determined. rLj-RGD3 significantly decreased the tumor volumes and weights, and the maximum tumor volume and weight IR values were 53.2% (p<0.001) and 55.9% (p<0.001), respectively. The life expectancy of Panc-1-bearing nude mice treated with rLj-RGD3 was increased by 56.3% (p<0.001). Meanwhile, rLj-RGD3 promoted the expression of Bax, caspase-3, and caspase-9 and inhibited Bcl-2 and VEGF expression. In addition, rLj-RGD3 did not change FAK, PI3K and Akt expression, but p-FAK, p-PI3K and p-Akt, levels were down-regulated. These results show that rLj-RGD3 induced potent anti-tumor activity in vivo and suppressed the growth of transplanted Panc-1 cells in a nude mouse model, implying that rLj-RGD3 may serve as a potent clinical therapeutic agent for human pancreatic carcinoma.
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Duplication of Neuropeptide Y and Peptide YY in Nile tilapia Oreochromis niloticus and their roles in food intake regulation
Source:Peptides
Author(s): Peipei Yan, Jirong Jia, Guokun Yang, Dongfang Wang, Caiyun Sun, Wensheng Li
In vertebrates, the neuropeptide Y (NPY) family peptides have been recognized as key players in food intake regulation. NPY centrally promotes feeding, while peptide YY (PYY) and pancreatic polypeptide (PP) mediate satiety. The teleost tetraploidization is well-known to generate duplicates of both NPY and PYY; however, the functional diversification between the duplicate genes, especially in the regulation of food intake, remains unknown. In this study, we identified the two duplicates of NPY and PYY in Nile tilapia (Oreochromis niloticus). Both NPYa and NPYb were primarily expressed in the central nervous system (CNS), but the mRNA levels of NPYb were markedly lower than those of NPYa. Hypothalamic mRNA expression of NPYa, but not NPYb, decreased after feeding and increased after 7-days of fasting. However, both NPYa and NPYb caused a significant increase in food intake after an intracranial injection of 50ng/g body weight dose. PYYb, one of the duplicates of PYY, had an extremely high expression in the foregut and midgut, whereas another form of duplicate PYYa showed only moderate expression in the CNS. Both hypothalamic PYYa and foregut PYYb mRNA expression increased after feeding and decreased after 7-days of fasting. Furthermore, the intracranial injection of PYYb decreased food intake, but PYYa had no significant effect. Our results suggested that although the mature peptides of NPYa and NPYb can both stimulate food intake, NPYa is the main endogenous functional NPY for feeding regulation. A functional division has been identified in the duplicates of PYY, which deems PYYb as a gut-derived anorexigenic peptide and PYYa as a CNS-specific PYY in Nile tilapia.
http://ift.tt/2hzGVmu
Increased plasma orexin-A levels in patients with insomnia disorder are not associated with prepro-orexin or orexin receptor gene polymorphisms
Source:Peptides
Author(s): Shi Tang, Weiwei Huang, Shanshan Lu, Lili Lu, Guohua Li, Xu Chen, Xiaomin Liu, Xin Lv, Zhangning Zhao, Ruisheng Duan, Yifeng Du, Jiyou Tang
Orexins, also known as hypocretins, play a regulatory role in the sleep-wake cycle by activating orexin receptors. Previous animal studies have shown that sleep deprivation can elevate orexinergic peptide levels. However, the relationship between insomnia disorder and orexin-A levels in humans has not been explored. In the current study, we examined plasma orexin-A levels in patients with insomnia disorder and in normal sleepers. We also studied the possible mechanisms underlying changes in orexin-A levels between the study groups; this included investigations of prepro-orexin and orexin receptor gene polymorphisms as well as exploration of other variables. We measured plasma orexin-A levels in 228 patients with insomnia disorder and 282 normal sleepers. The results indicated that the patients with insomnia disorder had significantly higher orexin-A levels than normal sleepers (63.42±37.56 vs. 54.84±23.95pg/ml). A positive relationship was detected between orexin-A level and age in patients with insomnia disorder. Orexin-A levels were elevated in relation to course of insomnia, as well as in relation to increased Insomnia Severity Index score. None of the evaluated prepro-orexin gene single nucleotide polymorphisms were informative between the two study populations. After sequencing all orexin receptor exons, one variation (rs2271933) in the OX1R gene and one variation (rs2653349) in the OX2R gene were found. However, no significant differences were found in either genotypic or allelic frequency distributions between the two study groups. It is suggested that the increased plasma orexin-A levels in patients with insomnia disorder are associated with the course and severity of insomnia, but not with prepro-orexin and orexin receptor gene polymorphisms.
http://ift.tt/2hwKufK
The Effects of Urotensin II on Migration and Invasion Are Mediated by NADPH Oxidase-derived Reactive Oxygen Species through the c-Jun N-terminal Kinase Pathway in Human Hepatoma Cells
Source:Peptides
Author(s): Ying-ying Li, Zheng-ming Shi, Xiao-tong Yu, Ping Feng, Xue-Jiang Wang
AimsUrotensin II (UII) is a vasoactive neuropeptide involved in migration and invasion in various cell types. However, the effects of UII on human hepatoma cells still remain unclear. The aim of this study was to investigate the role and mechanism of UII on migration and invasion in human hepatoma cells.MethodsMigration was measured by wound healing assays and a Transwell® methodology, and invasion was analyzed using Matrigel® invasion chambers. Reactive oxygen species (ROS) levels were detected using a 2′, 7′-dichlorofluorescein diacetate probe, and flow cytometry, and protein expression levels were evaluated by western blotting. Cell proliferation and actin polymerization were examined using cell proliferation reagent WST-1 and F-actin immunohistochemistry staining.ResultsExposure to UII promoted migration and invasion in hepatoma cells compared with that in cells without UII. UII also increased matrix metalloproteinase-2 (MMP2) expression in a time-independent manner. Furthermore, UII markedly enhanced ROS generation and NADPH oxidase subunit expression, and consequently facilitated the phosphorylation of c-Jun N-terminal kinase (JNK). The UT antagonist urantide or the antioxidant/NADPH oxidase inhibitor apocynin decreased UII-induced ROS production. JNK phosphorylation, migration, invasion, and MMP9/2 expression were also reversed by pretreatment with apocynin. Urantide and JNK inhibitor SP600125 abrogated migration, invasion, or MMP9/2 expression in response to UII. UII induced actin polymerization and fascin protein expression, and could be reversed by apocynin and SP600125.ConclusionsExogenous UII induced migration and invasion in hepatoma cells that mainly involved NADPH oxidase-derived ROS through JNK activation. UT played an additional role in regulating hepatoma cells migration and invasion. Thus, our data suggested an important effect of UII in hepatocellular carcinoma metastasis.
http://ift.tt/2hwQ1TO
Preventing Implant-Associated Infections by Silver Coating.
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Preventing Implant-Associated Infections by Silver Coating.
Antimicrob Agents Chemother. 2016 Apr;60(4):2467-75
Authors: Kuehl R, Brunetto PS, Woischnig AK, Varisco M, Rajacic Z, Vosbeck J, Terracciano L, Fromm KM, Khanna N
Abstract
Implant-associated infections (IAIs) are a dreaded complication mainly caused by biofilm-forming staphylococci. Implant surfaces preventing microbial colonization would be desirable. We examined the preventive effect of a silver-coated titanium-aluminum-niobium (TiAlNb) alloy. The surface elicited a strong, inoculum-dependent activity againstStaphylococcus epidermidisandStaphylococcus aureusin an agar inhibition assay. Gamma sterilization and alcohol disinfection did not alter the effect. In a tissue cage mouse model, silver coating of TiAlNb cages prevented perioperative infections in an inoculum-dependent manner and led to a 100% prevention rate after challenge with 2 × 10(6)CFU ofS. epidermidisper cage. InS. aureusinfections, silver coating had only limited effect. Similarly, daptomycin or vancomycin prophylaxis alone did not preventS. aureusinfections. However, silver coating combined with daptomycin or vancomycin prophylaxis thwarted methicillin-resistantS. aureusinfections at a prevention rate of 100% or 33%, respectively. Moreover, silver release from the surface was independent of infection and occurred rapidly after implantation. On day 2, a peak of 82 μg Ag/ml was reached in the cage fluid, corresponding to almost 6× the MIC of the staphylococci. Cytotoxicity toward leukocytes in the cage was low and temporary. Surrounding tissue did not reveal histological signs of silver toxicity.In vitro, no emergence of silver resistance was observed in several clinical strains of staphylococci upon serial subinhibitory silver exposures. In conclusion, our data demonstrate that silver-coated TiAlNb is potent for prevention of IAIs and thus can be considered for clinical application.
PMID: 26883700 [PubMed - indexed for MEDLINE]
http://ift.tt/2hzCOql
DHA-derived oxylipins, neuroprostanes and protectins, differentially and dose-dependently modulate the inflammatory response in human macrophages: putative mechanisms through PPAR activation
Publication date: Available online 14 December 2016
Source:Free Radical Biology and Medicine
Author(s): Rémy Bosviel, Laurie Joumard-Cubizolles, Giulia Chinetti-Gbaguidi, Dominique Bayle, Corinne Copin, Nathalie Hennuyer, Isabelle Duplan, Bart Staels, Giuseppe Zanoni, Alessio Porta, Laurence Balas, Jean-Marie Galano, Camille Oger, Andrzej Mazur, Thierry Durand, Cécile Gladine
Whereas the anti-inflammatory properties and mechanisms of action of long chain ω3 PUFAs have been abundantly investigated, research gaps remain regarding the respective contribution and mechanisms of action of their oxygenated metabolites collectively known as oxylipins. We conducted a dose-dependent and comparative study in human primary macrophages aiming to compare the anti-inflammatory activity of two types of DHA-derived oxylipins including the well-described protectins (NPD1 and PDX), formed through lipoxygenase pathway and the neuroprostanes (14-A4t- and 4-F4t-NeuroP) formed through free-radical mediated oxygenation and expected to be new anti-inflammatory mediators. Considering the potential ability of these DHA-derived oxylipins to bind PPARs and knowing the central role of these transcription factors in the regulation of macrophage inflammatory response, we performed transactivation assays to compare the ability of protectins and neuroprostanes to activate PPARs. All molecules significantly reduced mRNA levels of cytokines such as IL-6 and TNF-α, however not at the same doses. NPD1 showed the most effect at 0.1µM (−14.9%, p<0.05 for IL-6 and −26.7%, p<0.05 for TNF-α) while the three other molecules had greater effects at 10µM, with the strongest result due to the cyclopentenone neuroprostane, 14-A4t-NeuroP (−49.8%, p<0.001 and −40.8%, p<0.001, respectively). Part of the anti-inflammatory properties of the DHA-derived oxylipins investigated could be linked to their activation of PPARs. Indeed, all tested oxylipins significantly activated PPARγ, with 14-A4t-NeuroP leading to the strongest activation, and NPD1 and PDX also activated PPARα. In conclusion, our results show that neuroprostanes and more especially cyclopentenone neuroprostanes have potent anti-inflammatory activities similar or even more pronounced than protectins supporting that neuroprostanes should be considered as important contributors to the anti-inflammatory effects of DHA.
Graphical abstract
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Investigating rennet coagulation properties of recombined highly concentrated micellar casein concentrate and cream for use in cheese making
Source:Journal of Dairy Science
Author(s): Y. Lu, D.J. McMahon, A.H. Vollmer
Highly concentrated micellar casein concentrate (HC-MCC) contains ∼18% casein with ∼70% of whey proteins removed by microfiltration and diafiltration of skim milk, followed by vacuum evaporation for further concentration. When blended with cream, HC-MCC forms recombined concentrated milk (RCM), which could be used as a starting material in cheese making. Our objective was to investigate the rennet coagulation properties of RCM while varying parameters such as casein level, pH, rennet level, and coagulation temperature. The HC-MCC was mixed with cream using low shear at 50°C for 10 min, followed by cooling to 31, 28, or 25°C and adding rennet, and rheological properties were determined. Rennet coagulation time [RCT, the time at which storage modulus (G′) = loss modulus (G′′)] decreased from 8.7 to 7.4 min as casein level increased from 3.2 to 5.7%, without a significant additional difference in RCT at casein levels >5.7%. The initial G′′ (G′′0) increased about 10-fold when casein levels were increased from 3.2 to 10.9%, whereas no change in initial G′ (G′0) was observed. When G′ was measured relative to RCT (i.e., 1, 1.5, or 2 times RCT after RCT was reached, and expressed as G′1, G′1.5, and G′2), log relationship was found between relative G′ and casein level (R2 > 0.94). Lowering coagulation temperature from 31 to 25°C increased G′′0 by 6 fold and extended RCT from 7.4 to 9.5 min. After coagulation, relative G′ was initially higher at the lower temperature with G′1 of 3.6 Pa at 25°C and 2.0 Pa at 31°C, but delayed in further development with G′2 of 0.8 kPa at 25°C and 1.1 kPa at 31°C. Lowering pH of RCM from 6.6 to 6.2 resulted in reduced RCT from 11.9 to 6.5 min with increased relative G′ after coagulation. When less rennet was used, RCT increased in a linear inverse relationship without changes in relative G′ or G′′. The microstructure of RCM coagulum (∼11% casein), observed using transmission electron microscopy, confirmed that RCM curd had a rigid protein matrix containing extensively cross-linked protein strands.
http://ift.tt/2hwPX6B
Short communication: Analytical method and amount of preservative added to milk samples may alter milk urea nitrogen measurements
Source:Journal of Dairy Science
Author(s): Holley L. Weeks, Alexander N. Hristov
Milk urea N (MUN) is used by dairy nutritionists and producers to monitor dietary protein intake and is indicative of N utilization in lactating dairy cows. Two experiments were conducted to explore discrepancies in MUN results provided by 3 milk processing laboratories using different methods. An additional experiment was conducted to evaluate the effect of 2-bromo-2-nitropropane-1, 3-diol (bronopol) on MUN analysis. In experiment 1, 10 replicates of bulk tank milk samples, collected from the Pennsylvania State University's Dairy Center over 5 consecutive days, were sent to 3 milk processing laboratories in Pennsylvania. Average MUN differed between laboratory A (14.9 ± 0.40 mg/dL; analyzed on MilkoScan 4000; Foss, Hillerød, Denmark), laboratory B (6.5 ± 0.17 mg/dL; MilkoScan FT + 6000), and laboratory C (7.4 ± 0.36 mg/dL; MilkoScan 6000). In experiment 2, milk samples were spiked with urea at 0 (7.3 to 15.0 mg/dL, depending on the laboratory analyzing the samples), 17.2, 34.2, and 51.5 mg/dL of milk. Two 35-mL samples from each urea level were sent to the 3 laboratories used in experiment 1. Average analyzed MUN was greater than predicted (calculated for each laboratory based on the control; 0 mg of added urea): for laboratory A (23.2 vs. 21.0 mg/dL), laboratory B (18.0 vs. 13.3 mg/dL), and laboratory C (20.6 vs. 15.2 mg/dL). In experiment 3, replicated milk samples were preserved with 0 to 1.35 mg of bronopol/mL of milk and submitted to one milk processing laboratory that analyzed MUN using 2 different methods. Milk samples with increasing amounts of bronopol ranged in MUN concentration from 7.7 to 11.9 mg/dL and from 9.0 to 9.3 mg/dL when analyzed on MilkoScan 4000 or CL 10 (EuroChem, Moscow, Russia), respectively. In conclusion, measured MUN concentrations varied due to analytical procedure used by milk processing laboratories and were affected by the amount of bronopol used to preserve milk sample, when milk was analyzed using a mid-infrared analyzer. Thus, it is important to maintain consistency in milk sample preservation and analysis to ensure precision of MUN results.
http://ift.tt/2hzwP53
Addition of sodium caseinate to skim milk increases nonsedimentable casein and causes significant changes in rennet-induced gelation, heat stability, and ethanol stability
Source:Journal of Dairy Science
Author(s): Yingchen Lin, Alan L. Kelly, James A. O'Mahony, Timothy P. Guinee
The protein content of skim milk was increased from 3.3 to 4.1% (wt/wt) by the addition of a blend of skim milk powder and sodium caseinate (NaCas), in which the weight ratio of skim milk powder to NaCas was varied from 0.8:0.0 to 0.0:0.8. Addition of NaCas increased the levels of nonsedimentable casein (from ∼6 to 18% of total casein) and calcium (from ∼36 to 43% of total calcium) and reduced the turbidity of the fortified milk, to a degree depending on level of NaCas added. Rennet gelation was adversely affected by the addition of NaCas at 0.2% (wt/wt) and completely inhibited at NaCas ≥0.4% (wt/wt). Rennet-induced hydrolysis was not affected by added NaCas. The proportion of total casein that was nonsedimentable on centrifugation (3,000 × g, 1 h, 25°C) of the rennet-treated milk after incubation for 1 h at 31°C increased significantly on addition of NaCas at ≥0.4% (wt/wt). Heat stability in the pH range 6.7 to 7.2 and ethanol stability at pH 6.4 were enhanced by the addition of NaCas. It is suggested that the negative effect of NaCas on rennet gelation is due to the increase in nonsedimentable casein, which upon hydrolysis by chymosin forms into small nonsedimentable particles that physically come between, and impede the aggregation of, rennet-altered para-casein micelles, and thereby inhibit the development of a gel network.
http://ift.tt/2hwP4e3
Rapid assessment of bovine colostrum quality: How reliable are transmission infrared spectroscopy, and digital and optical refractometers?
Source:Journal of Dairy Science
Author(s): I. Elsohaby, J.T. McClure, M. Cameron, L.C. Heider, G.P. Keefe
The objectives of this study were to evaluate the performance of the transmission infrared (IR) spectroscopic method and digital and optical Brix refractometers for measurement of colostral IgG concentration and assessment of colostrum quality of dairy cows. Colostrum samples (n = 258) were collected from Holstein cows on 30 commercial dairy farms in Nova Scotia and Newfoundland, Canada. Colostral IgG concentrations of 255 samples were measured by the reference radial immunodiffusion (RID) assay and IR spectroscopy. The Brix scores were determined on 240 of these samples using both the digital and optical Brix refractometers. Approximately half (48%) of the colostrum samples had RID IgG concentrations <50 g/L, which was the cut-point for poor quality. The correlation between RID and IR IgG concentrations was 0.88. The correlations between RID IgG concentration and Brix scores, as determined by the digital and optical refractometers, were 0.72 and 0.71, respectively. The optimal cutoff levels for distinguishing good- and poor-quality colostrum using IR spectroscopy, and digital and optical Brix refractometers were at 35 g/L and 23% Brix, respectively. The IR spectroscopy showed higher sensitivity (90%) and specificity (86%) than the digital (74 and 80%, respectively) and optical (73 and 80%, respectively) Brix refractometers for assessment of colostrum quality, as compared with RID. In conclusion, the transmission-IR spectroscopy is a rapid and accurate method for assessing colostrum quality, but is a laboratory-based method, whereas Brix refractometers were less accurate but could be used on-farm.
http://ift.tt/2hzworf
Pathway-based genome-wide association analysis of milk coagulation properties, curd firmness, cheese yield, and curd nutrient recovery in dairy cattle
Source:Journal of Dairy Science
Author(s): C. Dadousis, S. Pegolo, G.J.M. Rosa, D. Gianola, G. Bittante, A. Cecchinato
It is becoming common to complement genome-wide association studies (GWAS) with gene-set enrichment analysis to deepen the understanding of the biological pathways affecting quantitative traits. Our objective was to conduct a gene ontology and pathway-based analysis to identify possible biological mechanisms involved in the regulation of bovine milk technological traits: coagulation properties, curd firmness modeling, individual cheese yield (CY), and milk nutrient recovery into the curd (REC) or whey loss traits. Results from 2 previous GWAS studies using 1,011 cows genotyped for 50k single nucleotide polymorphisms were used. Overall, the phenotypes analyzed consisted of 3 traditional milk coagulation property measures [RCT: rennet coagulation time defined as the time (min) from addition of enzyme to the beginning of coagulation; k20: the interval (min) from RCT to the time at which a curd firmness of 20 mm is attained; a30: a measure of the extent of curd firmness (mm) 30 min after coagulant addition], 6 curd firmness modeling traits [RCTeq: RCT estimated through the CF equation (min); CFP: potential asymptotic curd firmness (mm); kCF: curd-firming rate constant (% × min−1); kSR: syneresis rate constant (% × min−1); CFmax: maximum curd firmness (mm); and tmax: time to CFmax (min)], 3 individual CY-related traits expressing the weight of fresh curd (%CYCURD), curd solids (%CYSOLIDS), and curd moisture (%CYWATER) as a percentage of weight of milk processed and 4 milk nutrient and energy recoveries in the curd (RECFAT, RECPROTEIN, RECSOLIDS, and RECENERGY calculated as the % ratio between the nutrient in curd and the corresponding nutrient in processed milk), milk pH, and protein percentage. Each trait was analyzed separately. In total, 13,269 annotated genes were used in the analysis. The Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway databases were queried for enrichment analyses. Overall, 21 Gene Ontology and 17 Kyoto Encyclopedia of Genes and Genomes categories were significantly associated (false discovery rate at 5%) with 7 traits (RCT, RCTeq, kCF, %CYSOLIDS, RECFAT, RECSOLIDS, and RECENERGY), with some being in common between traits. The significantly enriched categories included calcium signaling pathway, salivary secretion, metabolic pathways, carbohydrate digestion and absorption, the tight junction and the phosphatidylinositol pathways, as well as pathways related to the bovine mammary gland health status, and contained a total of 150 genes spanning all chromosomes but 9, 20, and 27. This study provided new insights into the regulation of bovine milk coagulation and cheese ability that were not captured by the GWAS.
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Source of supplemental dietary copper, zinc, and manganese affects fecal microbial relative abundance in lactating dairy cows
Source:Journal of Dairy Science
Author(s): M.J. Faulkner, B.A. Wenner, L.M. Solden, W.P. Weiss
Appropriate trace mineral supplementation can improve immune response and hoof health in cattle and at much higher rates of supplementation to swine and poultry can alter microbial colonization of the gut, resulting in improved gut health. Diet can influence fecal microbial excretion in cattle, and the fecal microbiome may serve as a means for assessing gastrointestinal microbial changes. We hypothesized that feeding diets that differed in source of supplemental Cu, Zn, or Mn would alter the relative abundance of fecal microbes in lactating dairy cattle and that organic Zn would have the greatest effect. Twenty-four cows were fed diets devoid of supplemental Cu, Zn, and Mn for a 16-d preliminary phase (basal diet provided 9, 29, and 32 mg/kg of Cu, Zn, and Mn, respectively), and then were randomly assigned to 1 of 3 treatment diets (n = 8 cows/treatment): one group of cows was fed supplemental Cu, Zn, and Mn from sulfate minerals; the second group was fed glycinate minerals; and the third group was fed Cu and Mn sulfate with glycinate Zn. Assayed total dietary concentrations were approximately 21, 73, and 72 mg/kg for Cu, Zn, and Mn, respectively. Milk production (averaged 38.8 kg/d), DMI (averaged 25.8 kg/d), and milk components were not affected by treatment. Fecal DNA was extracted, amplified using a universal primer targeting the V4-V5 hypervariable region of the 16S rRNA gene, and sequenced to compare microbial community composition between treatments. Relative abundances of Treponema species-level operational taxonomic units (OTU) were less for animals fed Cu and Mn sulfate with glycinate Zn compared with sulfates alone, but were similar to animals fed glycinate mineral sources. Relative abundances for exclusive glycinate mineral and sulfate mineral treatments were similar. Treponema OTU and cultured representatives are often associated with bovine digital dermatitis. These data may provide an additional link between organic Zn supplementation and improved hoof health. To our knowledge this is the first report of a dietary treatment decreasing the relative abundance of Treponema OTU in cattle feces; however, the potential benefits of this response on overall animal health and the mechanism for the observed responses are unknown and warrant further investigation.
http://ift.tt/2hzwLSR
The effect of storage conditions on the composition and functional properties of blended bulk tank milk
Source:Journal of Dairy Science
Author(s): A. O'Connell, A.L. Kelly, J. Tobin, P.L. Ruegg, D. Gleeson
The objective of this study was to investigate the effects of storage temperature and duration on the composition and functional properties of bulk tank milk when fresh milk was added to the bulk tank twice daily. The bulk tank milk temperature was set at each of 3 temperatures (2, 4, and 6°C) in each of 3 tanks on 2 occasions during two 6-wk periods. Period 1 was undertaken in August and September when all cows were in mid lactation, and period 2 was undertaken in October and November when all cows were in late lactation. Bulk tank milk stored at the 3 temperatures was sampled at 24-h intervals during storage periods of 0 to 96 h. Compositional parameters were measured for all bulk tank milk samples, including gross composition and quantification of nitrogen compounds, casein fractions, free amino acids, and Ca and P contents. The somatic cell count, heat stability, titratable acidity, and rennetability of bulk tank milk samples were also assessed. Almost all parameters differed between mid and late lactation; however, the interaction between lactation, storage temperature, and storage duration was significant for only 3 parameters: protein content and concentrations of free cysteic acid and free glutamic acid. The interaction between storage temperature and storage time was not significant for any parameter measured, and temperature had no effect on any parameter except lysine: lysine content was higher at 6°C than at 2°C. During 96 h of storage, the concentrations of some free amino acids (glutamic acid, lysine, and arginine) increased, which may indicate proteolytic activity during storage. Between 0 and 96 h, minimal deterioration was observed in functional properties (rennet coagulation time, curd firmness, and heat stability), which was most likely due to the dissociation of β-casein from the casein micelle, which can be reversed upon pasteurization. Thus, this study suggests that blended milk can be stored for up to 96 h at temperatures between 2°C and 6°C with little effect on its composition or functional properties.
http://ift.tt/2hwJEjp
Isolation and genetic identification of spore-formers associated with concentrated-milk processing in Nebraska
Source:Journal of Dairy Science
Author(s): Bismarck A. Martinez, Jayne Stratton, Andreia Bianchini
Spore-forming bacteria are heat-resistant microorganisms capable of surviving and germinating in milk after pasteurization. They have been reported to affect the quality of dairy products by the production of enzymes (lipolytic and proteolytic) under low-temperature conditions in fluid milk, and have become a limiting factor for milk powder in reaching some selective markets. The objective of this research was to isolate and identify the population of spore-forming bacteria (psychrotrophic and thermophilic strains) associated with concentrated milk processing in Nebraska. During 2 seasons, in-process milk samples from a commercial plant (raw, pasteurized, and concentrated) were collected and heat-treated (80°C/12 min) to recover only spore-formers. Samples were spread-plated using standard methods agar and incubated at 32°C to enumerate mesophilic spore counts. Heat-treated samples were also stored at 7°C and 55°C to recover spore-formers that had the ability to grow under those temperature conditions. Isolates obtained from incubation or storage conditions were identified using molecular techniques (16S or rpoB sequencing). Based on the identification of the isolates and their relatedness, strains found in raw, pasteurized, and concentrated milk were determined to be similar. Paenibacillus spp. were associated with both raw and concentrated milk. Due to their known ability to cause spoilage under refrigeration, this shows the potential risk associated with the transferring of these problematic organisms into other dairy products. Other Bacillus species found in concentrated milk included Bacillus clausii, Bacillus subtilis, Lysinibacillus sp., Bacillus safensis, Bacillus licheniformis, Bacillus sonorensis, and Brevibacillus sp., with the last 3 organisms being capable of growing at thermophilic temperatures. These strains can also be translocated to other dairy products, such as milk powder, representing a quality problem. The results of this research highlight the importance of understanding spore-formers associated with the processing of condensed milk, which then may allow for specific interventions to be applied to control these microorganisms in this processing chain. To our knowledge, this is the first study evaluating spore-formers associated with concentrated milk in the United States.
http://ift.tt/2hzrYR4
Effects of feeding betaine-containing liquid supplement to transition dairy cows
Source:Journal of Dairy Science
Author(s): A.P.A. Monteiro, J.K. Bernard, J.-R. Guo, X-S. Weng, S. Emanuele, R. Davis, G.E. Dahl, S. Tao
Betaine is a natural compound found in sugar beets that serves as a methyl donor and organic osmolyte when fed to animals. The objective was to evaluate the effect of feeding betaine-containing molasses on performance of transition dairy cows during late summer in 2 trials. In early September, cows were randomly assigned to betaine (BET) or control (CON) groups either shortly after dry off (trial 1; n = 10 per treatment) or 24 d before calving (trial 2; n = 8 per treatment) based on parity and previous mature equivalent milk yield. Cows were fed common diets supplemented either with a liquid supplement made of molasses from sugar cane and condensed beet solubles containing betaine [BET, 89.1 g/kg of dry matter (DM)] or a sugar cane molasses-based liquid supplement without betaine (CON) until 8 wk postpartum. The liquid supplements had similar nutrient contents and were fed at a rate of 1.1 and 1.4 kg DM/d for pre- and postpartum cows, respectively. Starting at their entry in the studies, cows were housed in the same freestall barn without a cooling system. After calving, all cows were housed in the same barn cooled by misters and fans and milked thrice daily. Intake was recorded daily and body weight and body condition score were assessed every 2 wk. Milk yield was recorded at each milking and composition was analyzed weekly. Blood samples were collected weekly from a subset of cows to assess concentrations of metabolites and AA. No treatment effects were apparent for DM intake and body weight in the prepartum and postpartum periods. For cows enrolled at dry off, BET supported higher milk yield (45.1 vs. 41.9 kg/d) and fat content (4.78 vs. 4.34%) and elevated plasma concentrations of nonesterified fatty acids and β-hydroxybutyrate in early lactation compared to CON. However, no differences were observed for milk yield, most milk component contents and yields, and blood metabolites between treatments for cows enrolled during the close-up period. Compared to cows in the CON group, BET cows enrolled during the far-off period tended to have lower plasma concentrations of Met, Thr, and Trp during the pre- and postpartum periods. They also had lower plasma concentrations of Lys and Phe before calving but higher plasma Gly concentration after parturition. In conclusion, feeding a betaine-containing liquid supplement from far-off through early lactation improves lactation performance but increases adipose tissue mobilization and production of ketone bodies in early lactation.
http://ift.tt/2hwDpfs
Rumination time and reticuloruminal temperature as possible predictors of dystocia in dairy cows
Source:Journal of Dairy Science
Author(s): L. Kovács, F.L. Kézér, F. Ruff, O. Szenci
The objectives of this study were to explore changes of rumination time and reticuloruminal pH and temperature of dairy cows and heifers (means ± standard deviation; age = 5.8 ± 1.9; parity = 2.7 ± 1.4; body condition score = 3.2 ± 0.2) with eutocic (EUT, n = 10) and dystocic calving (DYS, n = 8). The recording period lasted from 3 d before calving until 7 d in milk. For the comparison of rumination time and reticuloruminal characteristics between groups, time to return to baseline (the time interval required to return to baseline from the delivery of the calf) and area under the curve (AUC; both for prepartum and postpartum periods) were calculated for each parameter. Rumination time decreased from baseline 28 h before calving both for EUT and DYS cows; after 20 h before calving, it decreased to 32.4 ± 2.3 and 13.2 ± 2.0 min/4 h between 8 and 4 h before delivery in EUT and DYS cows, respectively, and then it decreased below 10 and 5 min during the last 4 h before calving. Until 12 h after delivery, rumination time reached 42.6 ± 2.7 and 51.0 ± 3.1 min/4 h in DYS and EUT dams, respectively; however, AUC and time to return to baseline suggested lower rumination activity in DYS cows than in EUT dams for the 168-h postpartum observational period. Reticuloruminal pH decreased from baseline 56 h before calving both for EUT and DYS cows, but did not differ between groups before delivery. Reticuloruminal pH showed a decreasing tendency and clear diurnal variation after calving for both EUT and DYS cows, with slightly higher AUC values in DYS cows. In DYS cows, reticuloruminal temperature decreased from baseline 32 h before calving by 0.23 ± 0.02°C, whereas in EUT cows such a decrease was found only 20 h before delivery (0.48 ± 0.05°C). The AUC of reticuloruminal temperature calculated for the prepartum period was greater in EUT cows than in DYS cows. During the first 4 h after calving, reticuloruminal temperature decreased from 39.68 ± 0.09 to 38.96 ± 0.10°C and from 39.80 ± 0.06 to 38.81 ± 0.08°C in EUT and DYS cows, respectively, and reached baseline levels after 35.4 ± 3.4 and 37.8 ± 4.2 h after calving in EUT and DYS cows, respectively. Based on our results, continuous monitoring of changes in rumination time and reticuloruminal temperature seems to be promising in the early detection of cows with a higher risk of dystocia. Depressed rumination activity of DYS cows after calving highlights the importance of the postpartum monitoring of cows experiencing difficulties at calving. The effect of dystocia on postpartum reticuloruminal pH was not pronounced.
http://ift.tt/2hzCNTh
Short communication: Inhibition of angiotensin 1-converting enzyme by peptides derived from variants of bovine β-casein upon apical exposure to a Caco-2 cell monolayer
Source:Journal of Dairy Science
Author(s): Bjørn Petrat-Melin, Thao T. Le, Hanne S. Møller, Lotte B. Larsen, Jette F. Young
This study investigated the consequence of genetically contingent AA substitutions in bovine β-casein (CN) genetic variants A1, A2, B, and I on the structure and bioactive potential of peptides following in vitro digestion. The β-CN variants were digested in vitro using pepsin and pancreatin, and a peptide profile was obtained by liquid chromatography tandem mass spectrometry, revealing among others, the β-casomorphin precursor peptides VYPFPGPIHN and VYPFPGPIPN, derived from variant A1/B and from A2/I, respectively. These 2 peptides were synthesized and assessed for angiotensin 1-converting enzyme (ACE) inhibitory capacity before and after incubation with a monolayer of Caco-2 intestinal cells. The VYPFPGPIHN was a stronger ACE inhibitor than VYPFPGPIPN, with the concentration needed to reach half-maximal inhibition (IC50) of 123 ± 14.2 µM versus 656 ± 7.6 µM. Exposure to a Caco-2 intestinal cell monolayer did not affect ACE inhibition by VYPFPGPIHN, but resulted in an almost 2-fold increase in inhibition by VYPFPGPIPN after incubation. Subsequent tandem mass spectrometric analysis identified the truncated peptide VYPFPGPIP, suggesting hydrolysis by a cell membrane associated peptidase. Thus, genetic variation in bovine β-CN results in the generation of peptides that differ in bioactivity, and are differently affected by intestinal brush border peptidases.
http://ift.tt/2hwO4GR
Effects of dietary physically effective neutral detergent fiber content on the feeding behavior, digestibility, and growth of 8- to 10-month-old Holstein replacement heifers
Source:Journal of Dairy Science
Author(s): H.R. Wang, Q. Chen, L.M. Chen, R.F. Ge, M.Z. Wang, L.H. Yu, J. Zhang
The objective of this study was to evaluate the effects of dietary physically effective neutral detergent fiber (peNDF) content on the feeding behavior, digestion, ruminal fermentation parameters, and growth of 8- to 10-mo-old dairy heifers and to predict the adequacy of dietary fiber in growing dairy heifers. Twenty-four Holstein dairy heifers (245 ± 10.8 d of age, 305.6 ± 8.5 kg initial live weight) were randomly divided into 4 treatments with 6 replicates as a completely randomized design. During the 60-d period with a 10-d adaptation, heifers were offered 1 of 4 diets, which were chemically identical but included different peNDF8.0 (particle size is >8 mm and <19 mm) content (% DM): 10.8, 13.5, 18.0, or 19.8%, which was achieved by chopping forage into different lengths (fine = 1 cm, short = 3 cm, medium = 5 cm, and long = 7 cm). The concentrate and silage were mixed and fed restrictedly and exclusive of forage (Chinese ryegrass hay) were offered ad libitum. The body weight and frame size of the heifers were measured every 15 d during the experimental period. Samples of the rumen content (2 h after the morning feeding) were taken for pH, ammonia, and volatile fatty acid determination. The dry matter intake and average daily gain of the heifers were not significantly affected by peNDF8.0 content. The body frame size (including withers height, body length, and heart girth) of the heifers was not increased significantly by enhanced peNDF8.0 content. Ruminal pH and ammonia concentration were both increased with increasing dietary peNDF8.0 content. The ruminal total volatile fatty acid concentration and percentage of acetate and butyrate profiles were not significantly affected by dietary peNDF8.0 content. However, the enhanced peNDF8.0 content led to a decrease in the propionate percentage. The ratio of acetate to propionate in the 13.5% treatment was highest among the treatments. Increasing the particle size and dietary peNDF8.0 content resulted in increased eating and chewing time but had no effect on rumination time. Heifer total eating and chewing time and eating and chewing time per kilogram of dry matter intake were increased with increasing dietary peNDF8.0 content. The apparent digestibility of acid detergent fiber and crude protein was improved with an increasing content of dietary peNDF8.0. The results suggest that an optimal or advisable dietary particle size and peNDF8.0 content improves chewing activity, rumen fluid pH, and ruminal fermentation. The data based on feeding behavioral and growth responses of heifers as well as rumen fermentation and digestion by improving total eating and chewing time indicate that 18.0% dietary peNDF8.0 content is the most suitable for 8- to 10-mo-old Holstein heifers.
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Effects of milking stall dimensions on behavior of dairy cows during milking in different milking parlor types
Source:Journal of Dairy Science
Author(s): Y. Gómez, M. Terranova, M. Zähner, E. Hillmann, P. Savary
Dairy cow body size has increased over time because of breeding selection for higher milk yield, but milking stall dimensions have never been adjusted and are based on the practical experience of milking-machine manufacturers and advisory institutions. Narrow, limited milking stall dimensions might lead to behavioral changes during milking due to lack of comfort. The aim of this study was to examine the current space allowance in milking stalls on dairy farms and assess the effect of space allowance on cow behavior during milking. On 15 Swiss dairy farms, we measured clear milking stall dimensions and cow body dimensions. We calculated space ratios for length (SRlength) and width (SRwidth) by dividing the milking stall length or width by cow body length or belly width, respectively. When the space ratio was >1, we assumed that the body length or width of cow was smaller than the milking stall length or width. On each farm, 10 healthy cows were chosen for behavioral observation during 1 evening milking. We recorded rumination, elimination, and latency to enter the milking stall by direct observation. Hind leg activity was recorded using acceleration loggers. Data were analyzed using general linear mixed-effects models with farm as a random effect. Due to a strong collinearity between SRwidth and SRlength, we chose SRlength for further analysis, because it is based on skeletal characteristics. The SRlength was smallest in side-by-side parlors (1.07 ± 0.01) and largest in tandem parlors (1.18 ± 0.01). More cows had a tendency to ruminate with increasing SRlength (odds ratio: 1.8). None of hind leg activity, maximum peaks of hind leg accelerations, or latency to enter the milking stall were significantly affected by SRlength. Latency to enter the milking stall was longer for group milking parlors (side-by-side: 44.0 ± 3.2 s; herringbone: 34.3 ± 2.9 s) than for tandem parlors (19.0 ± 2.7 s). Milking parlor type had no effect on hind leg activity, maximum peaks of hind leg accelerations or rumination. The SRlength affected rumination behavior to some extent, indicating that cow comfort was positively affected by larger milking stall length. Because cow comfort is important for good milking performance, further investigations of milking stall dimensions for cow comfort and thus welfare are needed. Furthermore, the results showed that parlor type affected cow behavior, irrespective of SRlength, making future research necessary to identify the factors leading to this effect of parlor type.
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Lactation and body composition responses to fat and protein supplies during the dry period in under-conditioned dairy cows
Source:Journal of Dairy Science
Author(s): G. Jaurena, J.M. Moorby
An experiment was designed to study the effect of precalving supplementation with protein (Pr) and rumen-inert fat (F) on body composition and subsequent milk production and composition. Forty Holstein-Friesian dairy cows were allocated to 1 of 4 dietary treatments in the dry period (DP) based on a first-cut ryegrass silage, with 6 mature (in their third or greater pregnancy) and 4 young (in their second pregnancy) cows per treatment. These were low Pr, low F (silage alone); low Pr, high F (silage with 10% rumen-inert fat, mixed on a dry matter basis); high Pr, low F [silage with 5% high-protein corn gluten meal (CGM)]; and high Pr, high F (silage with 5% CGM and 10% rumen-inert fat). All the diets were individually offered ad libitum and dry matter intake (DMI) was recorded daily during the DP. After calving, all cows received ryegrass silage plus 8 kg/d of a commercial dairy concentrate. During the DP, DMI was higher for mature than for young cows. All animals recovered body condition score (0.13 units/wk, 1–5 scale), reaching a maximum score of 2.4 some days before calving. Precalving maximum muscle longissimus dorsi (LD) depth was greater for mature (47.5 mm) than for young cows (45.7 mm), and milk fat concentration was also higher for mature than for young cows (40.2 and 39.0 g/kg, respectively). Supplementation with CGM increased maximum LD depth (from 45.9 to 47.6 mm), calf birth weight (low Pr = 43.2, high Pr = 46.3 kg), and milk crude protein concentration (from 30.8 to 31.6 g/kg). Fat supplementation in the DP of the mature cows increased maximum back fat depth (from 3.6 to 4.5 mm), milk yield (low F = 26.3, high F = 28.7 kg/d), and Pr yields (low F = 837, high F = 899 g/d). Inclusion of F in the DP diets reduced casein concentration in milk at wk 3 of lactation from 26.3 to 24.5 g/kg. Milk CP yield was also increased by CGM supplementation when compared within cows receiving F-supplemented silages (low Pr, high F = 832 g/d; high Pr, high F= 877 g/d). It can be concluded that CGM supplementation in the DP increased subsequent milk Pr concentration, but milk Pr yield increased only in those animals also receiving F supplementation. Dry period diet supplementation with F increased maximum back fat depth and milk and CP yields in the mature cows, and led to more LD muscle mobilization during early lactation. Second-calving cows had a lower DMI and milk fat concentration than mature cows.
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Enterococcus faecium and Enterococcus durans isolated from cheese: Survival in the presence of medications under simulated gastrointestinal conditions and adhesion properties
Source:Journal of Dairy Science
Author(s): Daniel M.F. Amaral, Luana F. Silva, Sabrina N. Casarotti, Liane Caroline Sousa Nascimento, Ana Lúcia B. Penna
In this study, we evaluated the survival of Enterococcus faecium and Enterococcus durans, isolated from cheese, in the presence of medications and under simulated in vitro gastrointestinal conditions. The presence of genes encoding virulence factors, the susceptibility to antimicrobial agents, and adhesion properties were also assessed. Enterococcus faecium and E. durans both exhibited resistance to most of the tested medications but showed a large sensitivity to analgesics and antihypertensives; they also showed wide susceptibility to antimicrobial agents. Enterococcus durans SJRP29 had greater resistance to the presence of medications in comparison with the probiotic Lactobacillus acidophilus La-5. The strains, except for E. durans SJRP05, did not harbor virulence genes. Enterococcus durans SJRP14, SJRP17, and SJRP26 were sensitive to all tested antimicrobial agents. Enterococcus faecium was more stable during the simulation of gastrointestinal tract and showed greater viability. At the end of the assay, except for E. durans SJRP17, all strains showed high viability (>7 log cfu/mL). Enterococcus durans SJRP29 stood out from the other strains and was selected for further evaluation; it tolerated up to 3.0% NaCl at 30 and 37°C, besides having good adhesion properties (high values of auto-aggregation, co-aggregation, and hydrophobicity). Additionally, the microorganism did not show bile salt hydrolase activity or mucin degradation. These results encourage carrying out additional tests to evaluate the probiotic features by using in vitro dynamic models and in vivo tests before applying these strains to a food system.
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Technical note: Mammary gland ultrasonography to evaluate mammary parenchymal composition in prepubertal heifers
Source:Journal of Dairy Science
Author(s): R.L. Albino, S.E.F. Guimarães, K.M. Daniels, M.M.S. Fontes, A.F. Machado, G.B. dos Santos, M.I. Marcondes
Bovine mammary gland development studies are often terminal or involve invasive biopsy procedures. Therefore, noninvasive means of assessing mammary development should be considered as alternative methods in live animals. The objective was to test if mammary ultrasonography can be used as a noninvasive way to estimate mammary parenchyma (PAR) composition in prepubertal dairy heifers with different average daily body weight gains. In the 84 d preceding, the ultrasound exam heifers were maintained in 1 of 3 treatment groups. Individual heifers were fed a high gain (1 kg/d; n = 6), low gain (0.5 kg/d, n = 6), or maintenance (n = 6) treatment diet. To achieve desired body weight gains, heifers were fed differing amounts of the same silage-based diet. Mammary glands of 18 crossbred heifers Holstein:Gyr underwent a single mammary ultrasound exam immediately before heifer slaughter, which took place when heifers weighed 142.0 ± 8.0 kg and were 200 d old. The 4 mammary glands of each heifer were evaluated using a real-time B-mode ultrasound machine equipped with a 6.5-MHz micro-convex transducer. Digital images (8-bit) of glands were obtained and PAR was identified within gland. Average pixel values per unit of PAR area were determined for each gland and analyzed at the level of heifer. Pixel results were interpreted on the basis that lower average pixel values reflect PAR with relatively high amounts of protein as opposed to fat. To help validate that the pixel value within PAR is associated with composition of PAR, pixel findings were compared with histological [number of adipocytes in PAR (Nad) and epithelial area in PAR (Ep)] and biochemical [percent crude protein in PAR (%CP), percent ether extract in PAR (%EE), PAR weight (WPAR), and mammary fat pad weight (WFAT)] composition of PAR in these same heifers. Within PAR, %EE and WFAT were positively correlated with pixel values, whereas %CP, Ep, and Nad were negatively correlated. Parenchyma weight did not correlate with pixel values. Regression analyses (fixed effect log-pixel value; random effect treatment) were used to estimate Nad, Ep, %CP, %EE, WPAR, and WFAT. Sensitivity analysis of regression equations revealed that accuracy of tested equations ranged from 0.77 to 0.93 and precision ranged from 0.56 to 0.82. Concordance correlation coefficients of the equations ranged from 0.41 to 0.76. In conclusion, ultrasonography of PAR can accurately measure and predict PAR composition in prepubertal dairy heifers growing at various rates of gain.
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Diagnostic accuracy of a standardized scheme for identification of Streptococcus uberis in quarter milk samples: A comparison between conventional bacteriological examination, modified Rambach agar medium culturing, and 16S rRNA gene sequencing
Source:Journal of Dairy Science
Author(s): Regina Wald, Martina Baumgartner, Verena Urbantke, Beatrix Stessl, Thomas Wittek
Bacteriological examination of milk samples is a prerequisite for pathogen-specific therapy and aids in limiting antimicrobial resistance. The aims of this study were to establish a standardized scheme for reliable Streptococcus uberis identification in routine diagnosis and to evaluate the accuracy of conventional tests and growing patterns of Strep. uberis on a selective medium (modified Rambach agar medium, MRAM) using 16S rRNA gene sequencing analysis as a reference method. We obtained isolates of presumptive Strep. uberis (n = 336) from quarter milk samples of dairy cows with intramammary infections and classified the isolates into 2 clusters using biochemical characterization. In cluster 1 (n = 280), cocci grew as non-hemolytic colonies, hydrolyzing esculin, carrying no Lancefield antigen (A/B/C/D/G) or Christie Atkins Munch-Petersen factor, and their growth was inhibited on an Enterococcus agar. Production of β-d-galactosidase on MRAM was shown by 257 of the cluster 1 isolates (91.79%), and 16S rRNA gene sequencing verified 271 (96.79%) of the isolates to be Strep. uberis. In 264 isolates (94.29%), MRAM agreed with the sequencing results. In cluster 2 (n = 56), isolates showed different characteristics: 37 (66.07%) were β-d-galactosidase-positive, and based on 16S sequencing results, 36 (64.29%) were identified correctly as Strep. uberis using biochemical methods. Identification success in this group differed significantly between routine diagnosis and MRAM application: MRAM agreed with sequencing results in 47 isolates (83.93%). To identify Strep. uberis and differentiate it from other lactic acid bacteria in routine diagnosis, we suggest using catalase reaction, hemolysis, esculin hydrolysis, and growth on enterococci agar. Isolates that show a typical biochemical profile can be identified satisfactorily with these tests. For Strep. uberis isolates with divergent patterns, application of MRAM as a follow-up test increased the diagnostic accuracy to 94.64%.
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Survival and detection of coliforms, Enterobacteriaceae, and gram-negative bacteria in Greek yogurt
Source:Journal of Dairy Science
Author(s): C.J. Hervert, N.H. Martin, K.J. Boor, M. Wiedmann
Despite the widespread use of coliforms as indicator bacteria, increasing evidence suggests that the Enterobacteriaceae (EB) and total gram-negative groups more accurately reflect the hygienic status of high-temperature, short-time pasteurized milk and processing environments. If introduced into milk as postpasteurization contamination, these bacteria may grow to high levels and produce a wide range of sensory-related defects. However, limited information is available on the use and survival of bacterial hygiene indicators in dairy products outside of pasteurized fluid milk and cheese. The goal of this study was to (1) provide information on the survival of a diverse set of bacterial hygiene indicators in the low pH environment of Greek yogurt, (2) compare traditional and alternative detection methods for their ability to detect bacterial hygiene indicators in Greek yogurt, and (3) offer insight into optimal hygiene indicator groups for use in low-pH fermented dairy products. To this end, we screened 64 bacterial isolates, representing 24 dairy-relevant genera, for survival and detection in Greek yogurt using 5 testing methods. Before testing, isolates were inoculated into plain, 0% fat Greek yogurt (pH 4.35 to 4.65), followed by a 12-h hold period at 4 ± 1°C. Yogurts were subsequently tested using Coliform Petrifilm (3M, St. Paul, MN) to detect coliforms; Enterobacteriaceae Petrifilm (3M), violet red bile glucose agar and the D-Count (bioMérieux, Marcy-l'Étoile, France) to detect EB; and crystal violet tetrazolium agar (CVTA) to detect total gram-negative bacteria. Overall, the non-EB gram-negative isolates showed significantly larger log reductions 12 h after inoculation into Greek yogurt (based on bacterial numbers recovered on CVTA) compared with the coliform and noncoliform EB isolates tested. The methods evaluated varied in their ability to detect different microbial hygiene indicators in Greek yogurt. Crystal violet tetrazolium agar detected the highest portion of coliforms, whereas EB Petrifilm detected the highest portion of EB, as well as highest portion of total gram-negative bacteria. Additionally, the D-Count method allowed for faster detection of EB in yogurt by generating results in approximately 13 h rather than the 24 h required when using EB Petrifilm and violet red bile glucose agar. Results from this study indicate that the coliform and EB groups encompass a broad range of dairy-relevant gram-negative bacteria with the ability to survive in Greek yogurt, supporting their use as microbial hygiene indicator groups in low-pH fermented dairy products.
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Publication date: September 2017 Source: Free Radical Biology and Medicine, Volume 110 Author(s): Lucía Fernández-del-Río, Anish Nag, Elen...
