Association between GNRHR, LHR and IGF1 polymorphisms and timing of puberty in male Angus cattle

<p>Abstract</p> <p>Background</p> <p>In bovines, there are significant differences within and among beef breeds in the time when bulls reach puberty. Although the timing of puberty is likely to be a multigenic trait, previous studies indicate that there may also be single genes that exert major effects on the timing of puberty within the general population. Despite its economic importance, there are not many SNPs or genetic markers associated with the age of puberty in male cattle. In the present work, we selected three candidate genes, <it>GNRHR</it>, <it>LHR </it>and <it>IGF1</it>, and associated their polymorphisms with the age of puberty in Angus male cattle.</p> <p>Results</p> <p>After weaning, 276 Angus males were measured every month for weight (W), scrotal circumference (SC), sperm concentration (C) and percentage of motility (M). A total of 4 SNPs, two within <it>GNRHR</it>, one in <it>LHR </it>and one in <it>IGF1 </it>were genotyped using the pyrosequencing technique. <it>IGF1-SnaBI SNP </it>was significant associated (P < 0.01) with age at SC 28 cm, but it were not associated with age at M 10% and C 50 million. Genotype <it>CC </it>exhibited an average age at SC 28 cm of 7 and 11 days higher than <it>CT </it>(p = 0.037) and <it>TT </it>(p = 0.012), respectively. This SNP explained 1.5% of the genetic variance of age of puberty at SC28. <it>LHR-I499L</it>, <it>GNRHR-SNP5 </it>and <it>GNRHR-SNP6 </it>were not associated with any of the measurements. However, <it>GNRHR </it>haplotypes showed a suggestive association with age at SC 28 cm.</p> <p>Conclusions</p> <p>The findings presented here could support the hypothesis that <it>IGF1 </it>is a regulator of the arrival to puberty in male calves and is involved in the events that precede and initiate puberty in bull calves. Given that most studies in cattle, as well as in other mammals, were done in female, the present results are the first evidence of markers associated with age at puberty in male cattle.</p

The ELT-2 GATA-factor and the global regulation of transcription in the C. elegans intestine

AbstractA SAGE library was prepared from hand-dissected intestines from adult Caenorhabditis elegans, allowing the identification of >4000 intestinally-expressed genes; this gene inventory provides fundamental information for understanding intestine function, structure and development. Intestinally-expressed genes fall into two broad classes: widely-expressed “housekeeping” genes and genes that are either intestine-specific or significantly intestine-enriched. Within this latter class of genes, we identified a subset of highly-expressed highly-validated genes that are expressed either exclusively or primarily in the intestine. Over half of the encoded proteins are candidates for secretion into the intestinal lumen to hydrolyze the bacterial food (e.g. lysozymes, amoebapores, lipases and especially proteases). The promoters of this subset of intestine-specific/intestine-enriched genes were analyzed computationally, using both a word-counting method (RSAT oligo-analysis) and a method based on Gibbs sampling (MotifSampler). Both methods returned the same over-represented site, namely an extended GATA-related sequence of the general form AHTGATAARR, which agrees with experimentally determined cis-acting control sequences found in intestine genes over the past 20 years. All promoters in the subset contain such a site, compared to <5% for control promoters; moreover, our analysis suggests that the majority (perhaps all) of genes expressed exclusively or primarily in the worm intestine are likely to contain such a site in their promoters. There are three zinc-finger GATA-type factors that are candidates to bind this extended GATA site in the differentiating C. elegans intestine: ELT-2, ELT-4 and ELT-7. All evidence points to ELT-2 being the most important of the three. We show that worms in which both the elt-4 and the elt-7 genes have been deleted from the genome are essentially wildtype, demonstrating that ELT-2 provides all essential GATA-factor functions in the intestine. The SAGE analysis also identifies more than a hundred other transcription factors in the adult intestine but few show an RNAi-induced loss-of-function phenotype and none (other than ELT-2) show a phenotype primarily in the intestine. We thus propose a simple model in which the ELT-2 GATA factor directly participates in the transcription of all intestine-specific/intestine-enriched genes, from the early embryo through to the dying adult. Other intestinal transcription factors would thus modulate the action of ELT-2, depending on the worm's nutritional and physiological needs

Variability in gene expression underlies incomplete penetrance

The phenotypic differences between individual organisms can often be ascribed to underlying genetic and environmental variation. However, even genetically identical organisms in homogeneous environments vary, indicating that randomness in developmental processes such as gene expression may also generate diversity. To examine the consequences of gene expression variability in multicellular organisms, we studied intestinal specification in the nematode Caenorhabditis elegans in which wild-type cell fate is invariant and controlled by a small transcriptional network. Mutations in elements of this network can have indeterminate effects: some mutant embryos fail to develop intestinal cells, whereas others produce intestinal precursors. By counting transcripts of the genes in this network in individual embryos, we show that the expression of an otherwise redundant gene becomes highly variable in the mutants and that this variation is subjected to a threshold, producing an ON/OFF expression pattern of the master regulatory gene of intestinal differentiation. Our results demonstrate that mutations in developmental networks can expose otherwise buffered stochastic variability in gene expression, leading to pronounced phenotypic variation.National Institutes of Health (U.S.). Pioneer AwardMathematical Sciences Postdoctoral Research Fellowships (DMS-0603392)National Institutes of Health (U.S.). Ruth L. Kirschstein National Research Service Award (5F32GM080966

An Advanced Method to Assess the Diet of Free-Ranging Large Carnivores Based on Scats

<div><h3>Background</h3><p>The diet of free-ranging carnivores is an important part of their ecology. It is often determined from prey remains in scats. In many cases, scat analyses are the most efficient method but they require correction for potential biases. When the diet is expressed as proportions of consumed mass of each prey species, the consumed prey mass to excrete one scat needs to be determined and corrected for prey body mass because the proportion of digestible to indigestible matter increases with prey body mass. Prey body mass can be corrected for by conducting feeding experiments using prey of various body masses and fitting a regression between consumed prey mass to excrete one scat and prey body mass (correction factor 1). When the diet is expressed as proportions of consumed individuals of each prey species and includes prey animals not completely consumed, the actual mass of each prey consumed by the carnivore needs to be controlled for (correction factor 2). No previous study controlled for this second bias.</p> <h3>Methodology/Principal Findings</h3><p>Here we use an extended series of feeding experiments on a large carnivore, the cheetah (<em>Acinonyx jubatus</em>), to establish both correction factors. In contrast to previous studies which fitted a linear regression for correction factor 1, we fitted a biologically more meaningful exponential regression model where the consumed prey mass to excrete one scat reaches an asymptote at large prey sizes. Using our protocol, we also derive correction factor 1 and 2 for other carnivore species and apply them to published studies. We show that the new method increases the number and proportion of consumed individuals in the diet for large prey animals compared to the conventional method.</p> <h3>Conclusion/Significance</h3><p>Our results have important implications for the interpretation of scat-based studies in feeding ecology and the resolution of human-wildlife conflicts for the conservation of large carnivores.</p> </div

Assessing anti-rabies baiting – what happens on the ground?

BACKGROUND: Rabies is one of the most hazardous zoonoses in the world. Oral mass vaccination has developed into the most effective management method to control fox rabies. The future need to control the disease in large countries (i.e. Eastern Europe and the Americas) forces cost-benefit discussions. The 'Increase bait density' option refers to the usual management assumption that more baits per km(2 )could compensate for high fox abundance and override the imperfect supply of bait pieces to the individual fox. METHODS: We use a spatial simulation, which combines explicitly fox space use (tessellation polygons) and aeroplane flight lines (straight lines). The number of baits actually falling into each polygon is measured. The manager's strategic options are converted into changes of the resulting bait distribution on the ground. The comparison enables the rating of the options with respect to the management aim (i.e. accessibility of baits). RESULTS: Above 5% (approx. 10%) of all fox groups without any bait (at most 5 baits) relate to the baiting strategy applied in the field (1 km spaced parallel flight lines, 20 baits per km(2 )distributed) under habitat conditions comparable to middle and western Europe (fox group home-range 1 km(2), 2.5 adults; reference strategy). Increasing the bait density on the same flight-line pattern neither reduces the number of under-baited fox group home-ranges, nor improves the management outcome and hence wastes resources. However, reducing the flight line distance provides a more even bait distribution and thus compensates for missed fox groups or extra high fox density. The reference strategy's bait density can be reduced when accounting for the missed fox groups. The management result with the proper strategy is likely the same but with reduced costs. CONCLUSION: There is no overall optimal strategy for the bait distribution in large areas. For major parts of the landscape, the reference strategy will be more competitive. In situations where set backs are attributed to non-homogeneous bait accessibility the distribution scheme has to be refined zone-based (i.e. increase of the flight line length per unit area). However, increase in bait density above the reference strategy appears inappropriate at least for non-urban abundance conditions of the red fox

Emergency vaccination of rabies under limited resources – combating or containing?

BACKGROUND: Rabies is the most important viral zoonosis from a global perspective. Worldwide efforts to combat the disease by oral vaccination of reservoirs have managed to eradicate wildlife rabies in large areas of central Europe and North-America. Thus, repeated vaccination has been discontinued recently on a geographical scale. However, as rabies has not yet been eradicated globally, a serious risk of re-introduction remains. What is the best spatial design for an emergency vaccination program – particularly if resources are limited? Either, we treat a circular area around the detected case and run the risk of infected hosts leaving the limited control area, because a sufficient immunisation level has not yet been built up. Or, initially concentrate the SAME resources in order to establish a protective ring which is more distant from the infected local area, and which then holds out against the challenge of the approaching epidemic. METHODS: We developed a simulation model to contrast the two strategies for emergency vaccination. The spatial-explicit model is based on fox group home-ranges, which facilitates the simulation of rabies spread to larger areas relevant to management. We used individual-based fox groups to follow up the effects of vaccination in a detailed manner. Thus, regionally – bait distribution orientates itself to standard schemes of oral immunisation programs and locally – baits are assigned to individual foxes. RESULTS: Surprisingly, putting the controlled area ring-like around the outbreak does not outperform the circular area of the same size centred on the outbreak. Only during the very first baitings, does the ring area result in fewer breakouts. But then as rabies is eliminated within the circle area, the respective ring area fails, due to the non-controlled inner part. We attempt to take advantage of the initially fewer breakouts beyond the ring when applying a mixed strategy. Therefore, after a certain number of baitings, the area under control was increased for both strategies towards the same larger circular area. The circle-circle strategy still outperforms the ring-circle strategy and analysis of the spatial-temporal disease spread reveals why: improving control efficacy by means of a mixed strategy is impossible in the field, due to the build-up time of population immunity. CONCLUSION: For practical emergency management of a new outbreak of rabies, the ring-like application of oral vaccination is not a favourable strategy at all. Even if initial resources are substantially low and there is a serious risk of rabies cases outside the limited control area, our results suggest circular application instead of ring vaccination

Ehffekty selekcionnykh rabot v stade mjasnogo skota s primes'ju krovi gerefordskojj porody

Bulls obtained as crossbreds with Charolaise or Hereford cattle, were slaughtered at 450 kg and their fattening and slaughter vane estimated. Crossbreds of early maturing breeds (Hereford) gained more during the grazing season, but less during finishing. As compared with Black - and - White cattle the crossbreds of beef breeds were characterized by higher weight gains and lower food conversion. Howewer, the content of basie cuts in the carcass was similar.Проводилась оценка откормочного и убойного качества бычков помесей с примесью крови пород мясного направления: шароле и герефорд, убиваемых после достижения веса 450 кг. Помеси раньше созревающих пород (герефорд) прирастали более интенсивно в пастбищный период, а более медленно в период дополнительного откорма. В сравнении с черно-пестрым скотом помеси мясных пород характеризовались высшими привесами при более низкой степени использования кормов. Содержание основных отрубов в тушах было сходным

Rezul'taty mjasnojj produktivnosti pomesejj zubra so skotom otkormljaemykh do vesa tela 450 kg

The respective investigations were carried out at the Experiment Station Popielno, Polish Academy of Sciences on crosses heifer-calves and bull-callves of the genotypes of 50% Hereford, 25% black-and-white, 25% bison (16 heads) as well as 50% Charolais, 25% black-and-white and 25% bison (13 heads). The bull-calves were subjected to the control fattening from the 13th week of life to reaching the weight of 450 kg. It has been proved that cross bull-calves after bison x black-and-white dams with black-and-white x Hereford sires were significantly heavier at birth than their counterparts after Charolais sires. In later periods till the slaughter, no significant differences between both types of crosses in such traits, as body weight gains, carcass dressing, share of basic tissues in sides were found. Thus it may be concluded that both beef breeds can be successfully used for mating with F₁ crosses.Соответствующие исследования проводились в опытной станции Попельно Польской Академии Наук на помесях телках и бычках с генотипом: 50% герефорд, 25% черно-пестрой породы и 25% зубра (16 голов), а такхе 50% шароле, 25% черно-пестрой породы и 25% зубра (13 голов). Бычков подвергали контрольному откорму продолжающемуся с 13-го месяца жизни до достижения веса тела 450 кг. Установлено, что бычки-помеси самок зубра скрещенных с черно-белым скотом х быки породы герефорд имели существенно высшие весы тела при рождении, чем их соответственники после быков породы шароле. В более поздний период до убоя не наблюдались существенные различия между обеими типами помесей в таких признаках, как суточные привесы, убойный выход, участие основных тканей в полутуше. На этом основании можно заключать, что обе мясные породы могут одинакого успешно использоваться для спаривания с помесями FI