A mutation in the myostatin gene increases muscle mass and enhances racing performance in heterozygote dogs

Double muscling is a trait previously described in several mammalian species including cattle and sheep and is caused by mutations in the myostatin (MSTN) gene (previously referred to as GDF8). Here we describe a new mutation in MSTN found in the whippet dog breed that results in a double-muscled phenotype known as the “bully” whippet. Individuals with this phenotype carry two copies of a two-base-pair deletion in the third exon of MSTN leading to a premature stop codon at amino acid 313. Individuals carrying only one copy of the mutation are, on average, more muscular than wild-type individuals (p = 7.43 × 10⁻⁶; Kruskal-Wallis Test) and are significantly faster than individuals carrying the wild-type genotype in competitive racing events (Kendall's nonparametric measure, τ = 0.3619; p ≈ 0.00028). These results highlight the utility of performance-enhancing polymorphisms, marking the first time a mutation in MSTN has been quantitatively linked to increased athletic performance.     

Barrier activity in Candida albicans mediates pheromone degradation and promotes mating

Mating in Candida albicans and Saccharomyces cerevisiae is regulated by the secretion of peptide pheromones that initiate the mating process. An important regulator of pheromone activity in S. cerevisiae is barrier activity, involving an extracellular aspartyl protease encoded by the BAR1 gene that degrades the alpha pheromone. We have characterized an equivalent barrier activity in C. albicans and demonstrate that the loss of C. albicans BAR1 activity results in opaque a cells exhibiting hypersensitivity to alpha pheromone. Hypersensitivity to pheromone is clearly seen in halo assays; in response to alpha pheromone, a lawn of C. albicans Deltabar1 mutant cells produces a marked zone in which cell growth is inhibited, whereas wild-type strains fail to show halo formation. C. albicans mutants lacking BAR1 also exhibit a striking mating defect in a cells, but not in alpha cells, due to overstimulation of the response to alpha pheromone. The block to mating occurs prior to cell fusion, as very few mating zygotes were observed in mixes of Deltabar1 a and alpha cells. Finally, in a barrier assay using a highly pheromone-sensitive strain, we were able to demonstrate that barrier activity in C. albicans is dependent on Bar1p. These studies reveal that a barrier activity to alpha pheromone exists in C. albicans and that the activity is analogous to that caused by Bar1p in S. cerevisiae.     

Binge alcohol exposure in the second trimester attenuates fetal cerebral blood flow response to hypoxia.

Alcohol is detrimental to the developing brain and remains the leading cause of mental retardation in developed countries. The mechanism of alcohol brain damage remains elusive. Studies of neurological problems in adults have focused on alcohol's cerebrovascular effects, because alcoholism is a major risk factor for stroke and cerebrovascular injuries. However, few studies have examined similar cerebrovascular effects of fetal alcohol exposure. We examined the effect of chronic binge alcohol exposure during the second trimester on fetal cerebrovascular and metabolic responses to hypoxia in near-term sheep and tested the hypothesis that fetal alcohol exposure would attenuate cerebrovascular dilation to hypoxia. Pregnant ewes were infused with alcohol (1.5 g/kg) or saline intravenously at 60-90 days of gestation (full term = 150 days). At 125 days of gestation, we measured fetal cerebral blood flow (CBF) and oxygen metabolism at baseline and during hypoxia. Maternal blood alcohol averaged 214 +/- 5.9 mg/dl immediately after the 1.5-h infusion, with similar values throughout the month of infusion. Hypoxia resulted in a robust increase in CBF in saline-infused fetuses. However, the CBF response to hypoxia in fetuses chronically exposed to alcohol was significantly attenuated. Cerebral oxygen delivery decreased in both groups of fetuses during hypoxia but to a greater degree in the alcohol-exposed fetuses. Prenatal alcohol exposure during the second trimester attenuates cerebrovascular responses to hypoxia in the third trimester. Altered cerebrovascular reactivity might be one mechanism for alcohol-related brain damage and might set the stage for further brain injury if a hypoxic insult occurs.     

Population genetics reveals bidirectional fish movement across the Continental Divide via an interbasin water transfer

Interbasin water transfers are becoming an increasingly common tool to satisfy municipal and agricultural water demand, but their impacts on movement and gene flow of aquatic organisms are poorly understood. The Grand Ditch is an interbasin water transfer that diverts water from tributaries of the upper Colorado River on the west side of the Continental Divide to the upper Cache la Poudre River on the east side of the Continental Divide. We used single nucleotide polymorphisms to characterize population genetic structure in cutthroat trout (Oncorhynchus clarkii) and determine if fish utilize the Grand Ditch as a movement corridor. Samples were collected from two sites on the west side and three sites on the east side of the Continental Divide. We identified two or three genetic clusters, and relative migration rates and spatial distributions of admixed individuals indicated that the Grand Ditch facilitated bidirectional fish movement across the Continental Divide, a major biogeographic barrier. Previous studies have demonstrated ecological impacts of interbasin water transfers, but our study is one of the first to use genetics to understand how interbasin water transfers affect connectivity between previously isolated watersheds. We also discuss implications on native trout management and balancing water demand and biodiversity conservation.

     

Potential feedback between coral presence and farmerfish collective behavior promotes coral recovery

Stable between‐group differences in collective behavior have been documented in a variety of social taxa. Here we evaluate the effects of such variation, often termed collective or colony‐level personality, on coral recovery in a tropical marine farmerfish system. Groups of the farmerfish Stegastes nigricans cultivate and defend gardens of palatable algae on coral reefs in the Indo‐Pacific. These gardens can promote the recruitment, growth, and survival of corals by providing a refuge from coral predation. Here we experimentally evaluate whether the collective response of farmerfish colonies is correlated across intruder feeding guilds – herbivores, corallivores and egg‐eating predators. Further, we evaluate if overall colony responsiveness or situation‐specific responsiveness (i.e. towards herbivores, corallivores, or egg‐eaters in particular) best predicts the growth of outplanted corals. Finally, we experimentally manipulated communities within S. nigricans gardens, adding either macroalgae or large colonies of coral, to assess if farmerfish behavior changes in response to the communities they occupy. Between‐group differences in collective responsiveness were repeatable across intruder guilds. Despite this consistency, responsiveness towards corallivores (porcupinefish and ornate butterflyfish) was a better predictor of outplanted coral growth than responsiveness towards herbivores or egg‐eaters. Adding large corals to farmerfish gardens increased farmerfish attacks towards intruders, pointing to possible positive feedback loops between their aggression towards intruders and the presence of corals whose growth they facilitate. These data provide evidence that among‐group behavioral variation could strongly influence the ecological properties of whole communities.     

A Genome-wide Framework for Mapping Gene Regulation via Cellular Genetic Screens

1. Download high-res image (279KB)
2. Download full-size image

     

Engineering the acceptor substrate specificity in the xyloglucan endotransglycosylase TmXET6.3 from nasturtium seeds (Tropaeolum majus L.)

Plant Molecular Biology - The knowledge of substrate specificity of XET enzymes is important for the general understanding of metabolic pathways to challenge the established notion that these...     

The mitochondrial Nod-like receptor NLRX1 modifies apoptosis through SARM1

Molecular and Cellular Biochemistry - Acrolein is a α-β-unsaturated aldehyde and is toxic to human upon its exposure from the environment. Sources of exposure to acrolein can be from...     

Feeding ecological knowledge: the underutilised power of faecal DNA approaches for carnivore diet analysis

相似文献