4,635 research outputs found

    Genetic and environmental variations in reproductive performance of pasture-based dairy cows

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    Pasture-based dairy cows rely heavily on the availability of good quality grass and favorable environmental conditions to realize their maximum genetic potential for lactation and reproductive performance. Over one million records of gestation length, calving interval, number of services per conception, interval to first breeding and days open from four hundred and twenty eight pasture-based dairy farms in Tasmania, Australia, were evaluated. The hypothesis tested was that reproductive performance will be driven by multi-faceted genetic and environmental factors. It was evident that Holstein-Friesian and Jersey x Holstein-Friesian cows had similar reproductive performance, but calving intervals were longer in spring (390 days) than winter (362 days) and days open longer in autumn (136 days) than spring (77 days). There was a general decline in cow fertility that was mainly parity-driven because of the increases in interval to first breeding from 469 to 527 days, number of days open from 95 to 111 days and calving interval from 369 to 379 days as cow parity increased from 1 to 3. Our findings suggest that this decline in fertility could be attributable to decades of dairy cow breeding strategy that emphasized selection for high milk yield at the detriment of reproductive performance. In conclusion, there is the need for including reproductive traits in the selection index of pasture-based dairy cows and adjusting for seasonal variation

    A clustering property of highly-degenerate transcription factor binding sites in the mammalian genome

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    Transcription factor binding sites (TFBSs) are short DNA sequences interacting with transcription factors (TFs), which regulate gene expression. Due to the relatively short length of such binding sites, it is largely unclear how the specificity of protein–DNA interaction is achieved. Here, we have performed a genome-wide analysis of TFBS-like sequences for the transcriptional repressor, RE1 Silencing Transcription Factor (REST), as well as for several other representative mammalian TFs (c-myc, p53, HNF-1 and CREB). We find a nonrandom distribution of inexact sites for these TFs, referred to as highly-degenerate TFBSs, that are enriched around the cognate binding sites. Comparisons among human, mouse and rat orthologous promoters reveal that these highly-degenerate sites are conserved significantly more than expected by random chance, suggesting their positive selection during evolution. We propose that this arrangement provides a favorable genomic landscape for functional target site selection

    Next Generation Sequencing of Genotype Variants and Genetic Association between Heat Shock Proteins HSPA1B Single Nucleotide Polymorphism at the g.31829044 Locus and Heat Tolerance: A Pilot Quasi-Experimental Study

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    Heat tolerance and exertional heat stroke (EHS) are rare health conditions that have been described and characterised but have never been genetically solved. Knowledge of the role of single nucleotide polymorphisms (SNPs) in heat shock proteins (HSPs) genes and their associations with heat tolerance and EHS is limited. This pilot study aimed to identify SNP in HSPA1B, HSP90AA2 and DNAJA1 genes and their associations with heat tolerance and EHS history in a quasi-experimental design. Participants comprised Australian Defence Force members (ADF) who had a history of EHS and the general population. Genomic DNA samples were extracted from the venous blood samples of 48 participants, sequenced and analysed for SNP. Forty-four per cent (44%) of the participants were heat intolerant, and 29% had a history of EHS. Among participants with a history of EHS, there was an association between heat tolerance and HSPA1B SNP at the g.31829044 locus. However, there were no associations between HSPA1B and HSP90AA2 SNP and heat tolerance. All participants had the same distribution for the DNAJA1 SNP. In conclusion, the findings indicate an association between the HSPA1B genetic variant at the g.31829044 locus and heat tolerance among ADF participants with a history of EHS. Further research with a larger number of military participants will shed more light on the associations between HSP genes and heat tolerance

    NMFS / Interagency Working Group Evaluation of CITES Criteria and Guidelines.

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    EXECUTIVE SUMMARY: At present, the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) criteria used to assess whether a population qualifies for inclusion in the CITES Appendices relate to (A) size of the population, (B) area of distribution of the population, and (C) declines in the size of the population. Numeric guidelines are provided as indicators of a small population (less than 5,000 individuals), a small subpopulation (less than 500 individuals), a restricted area of distribution for a population (less than 10,000 km2), a restricted area of distribution for a subpopula-tion (less than 500 km2), a high rate of decline (a decrease of 50% or more in total within 5 years or two generations whichever is longer or, for a small wild population, a decline of 20% or more in total within ten years or three generations whichever is longer), large fluctuations (population size or area of distribution varies widely, rapidly and frequently, with a variation greater than one order of magnitude), and a short-term fluctuation (one of two years or less). The Working Group discussed several broad issues of relevance to the CITES criteria and guidelines. These included the importance of the historical extent of decline versus the recent rate of decline; the utility and validity of incorporating relative population productivity into decline criteria; the utility of absolute numbers for defining small populations or small areas; the appropriateness of generation times as time frames for examining declines; the importance of the magnitude and frequency of fluctuations as factors affecting risk of extinction; and the overall utility of numeric thresh-olds or guidelines

    Live Aircraft Encounter Visualization at FutureFlight Central

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    Researchers at the National Aeronautics and Space Administration (NASA) have developed an aircraft data streaming capability that can be used to visualize live aircraft in near real-time. During a joint Federal Aviation Administration (FAA)/NASA Airborne Collision Avoidance System flight series, test sorties between unmanned aircraft and manned intruder aircraft were shown in real-time at NASA Ames' FutureFlight Central tower facility as a virtual representation of the encounter. This capability leveraged existing live surveillance, video, and audio data streams distributed through a Live, Virtual, Constructive test environment, then depicted the encounter from the point of view of any aircraft in the system showing the proximity of the other aircraft. For the demonstration, position report data were sent to the ground from on-board sensors on the unmanned aircraft. The point of view can be change dynamically, allowing encounters from all angles to be observed. Visualizing the encounters in real-time provides a safe and effective method for observation of live flight testing and a strong alternative to travel to the remote test range

    Dynamical Masses for Low-Mass Pre-Main Sequence Stars: A Preliminary Physical Orbit for HD 98800 B

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    We report on Keck Interferometer observations of the double-lined binary (B) component of the quadruple pre-main sequence (PMS) system HD 98800. With these interferometric observations combined with astrometric measurements made by the Hubble Space Telescope Fine Guidance Sensors (FGS), and published radial velocity observations we have estimated preliminary visual and physical orbits of the HD 98800 B subsystem. Our orbit model calls for an inclination of 66.8 ±\pm 3.2 deg, and allows us to infer the masses and luminosities of the individual components. In particular we find component masses of 0.699 ±\pm 0.064 and 0.582 ±\pm 0.051 M_{\sun} for the Ba (primary) and Bb (secondary) components respectively. Modeling of the component SEDs finds temperatures and luminosities in agreement with previous studies, and coupled with the component mass estimates allows for comparison with PMS models in the low-mass regime with few empirical constraints. Solar abundance models seem to under-predict the inferred component temperatures and luminosities, while assuming slightly sub-solar abundances bring the models and observations into better agreement. The present preliminary orbit does not yet place significant constraints on existing pre-main sequence stellar models, but prospects for additional observations improving the orbit model and component parameters are very good.Comment: 20 pages, 6 figures, ApJ in press; tables 2 and 3 to be included in ApJ versio

    Lipogenic gene single nucleotide polymorphic DNA markers associated with intramuscular fat, fat melting point, and health-beneficial omega-3 long-chain polyunsaturated fatty acids in Australian pasture-based Bowen Genetics Forest Pastoral Angus, Hereford and Wagyu beef cattle

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    This study used targeted sequencing aimed at identifying single nucleotide polymorphisms (SNP) in lipogenic genes and their associations with health-beneficial omega-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA), intramuscular fat (IMF), and fat melting point (FMP) of the M. longissimus dorsi muscle in Australian pasture-based Bowen Genetics Forest Pastoral Angus, Hereford, and Wagyu cattle. It was hypothesized that SNP encoding for the fatty acid-binding protein 4 (FABP4), stearoyl-CoA desaturase (SCD), and fatty acid synthase (FASN) genes will be significantly associated with health-beneficial n-3 LC-PUFA and the meat eating quality traits of IMF and FMP in an Australian pasture-based beef production system. Two SNP mutations, g.21267406 T>C and g.21271264 C>A, in the SCD gene were significantly (p G and FMP, 18:1n-9, ALA, EPA, DHA, DPA, and total n-3 LC-PUFA were also detected. An SNP (g.44678794 G>A) in the FABP4 gene was associated with FMP. These results provide significant insights into the contributions of lipogenic genes to intramuscular fat deposition and the biosynthesis of health-beneficial n-3 LC-PUFA. The findings also unravel the potential use of lipogenic gene polymorphisms in marker-assisted selection to improve the content of health-promoting n-3 LC-PUFA and meat eating quality traits in Australian pasture-based Bowen Genetics Forest Pastoral Angus, Hereford, and Wagyu beef cattle

    Effects of a Combined Aquatic Exercise and Walking in Sedentary Obese Females Undergoing a Behavioral Weight-Loss Intervention

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    Background: The effects of the non-weight bearing method of aquatic exercise as a modality for weight loss have not been established. The purpose of this study was to examine the effects of a combined aquatic exercise and walking program compared to walking alone on body weight and selected variables in obese females undergoing a 16-week Standard Behavioral Treatment (SBT) program. Methods: Forty-four obese (BMI 34.9 ± 3.8 kg·m2) sedentary women (age=40.3 years ± 6.8 yrs) were randomly assigned to either an aquatic exercise (AE) group or a traditional walking (W) exercise only group. Both groups were also required to complete 3 sessions of home based walking per week, and reduce energy intake to facilitate weight loss. Results: In the AE group, total body weight, cardiorespiratory fitness, flexibility, strength, and health-related quality of life outcomes significantly improved over time similar to the W group. Significantly greater enjoyment scores also occurred in the AE group. Conclusion: Aquatic exercise in combination with walking can serve as an alternative to walking exercise alone for overweight women during periods of weight loss, and this can improve functional health status

    Nerve Agent Hydrolysis Activity Designed into a Human Drug Metabolism Enzyme

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    Organophosphorus (OP) nerve agents are potent suicide inhibitors of the essential neurotransmitter-regulating enzyme acetylcholinesterase. Due to their acute toxicity, there is significant interest in developing effective countermeasures to OP poisoning. Here we impart nerve agent hydrolysis activity into the human drug metabolism enzyme carboxylesterase 1. Using crystal structures of the target enzyme in complex with nerve agent as a guide, a pair of histidine and glutamic acid residues were designed proximal to the enzyme's native catalytic triad. The resultant variant protein demonstrated significantly increased rates of reactivation following exposure to sarin, soman, and cyclosarin. Importantly, the addition of these residues did not alter the high affinity binding of nerve agents to this protein. Thus, using two amino acid substitutions, a novel enzyme was created that efficiently converted a group of hemisubstrates, compounds that can start but not complete a reaction cycle, into bona fide substrates. Such approaches may lead to novel countermeasures for nerve agent poisoning
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