Effect of a trematode infection on growth,reproduction, and mortality of shorthead sculpin

Environmental Biology of Fishes - Shorthead sculpin (Cottus confusus Bailey and Bond, 1963) in Birch Creek, Idaho, were infected with the trematode Euryhelmis cotti (Simon, 1972). Our objective was...     

Brain serotonin deficiency leads to social communication deficits in mice

A deficit in brain serotonin is thought to be associated with deteriorated stress coping behaviour, affective disorders and exaggerated violence. We challenged this hypothesis in mice with a brain-specific serotonin depletion caused by a tryptophan hydroxylase 2 (TPH2) deficiency. We tested TPH2-deficient (Tph2^−/–) animals in two social situations. As juveniles, Tph2^−/− mice displayed reduced social contacts, whereas ultrasonic vocalizations (USVs) were unchanged within same-sex same-genotype pairings. Interestingly, juvenile females vocalized more than males across genotypes. Sexually naive adult males were exposed to fresh male or female urine, followed by an interaction with a conspecific, and re-exposed to urine. Although Tph2^−/− mice showed normal sexual preference, they were hyper-aggressive towards their interaction partners and did not vocalize in response to sexual cues. These results highlight that central serotonin is essential for prosocial behaviour, especially USV production in adulthood, but not for sexual preference.     

Reintroduced bighorn sheep: do females adjust maternal care to compensate for late-born young?

Little is known regarding the potential adjustment of maternal care towards late-born young by reintroduced female ungulates, which may be adapted to environments quite different than those at their release site. We compared nursing behaviors of young to investigate whether females would adjust maternal care toward late-born young between two populations of reintroduced bighorn sheep (Ovis canadensis) in Utah, USA. Neonates on Mount Timpanogos were born on average 28 days later in 2002 and 13 days later in 2003 than neonates in Rock Canyon. Suckling and weaning behaviors, however, were similar in 2002 and 2003 between those populations, except for the number of unsuccessful suckles, which was greater for young in Rock Canyon than for young on Mount Timpanogos during the middle of lactation in 2002. Our results provide preliminary evidence that females did not adjust maternal care to compensate for late-born young within the first 3 years following reintroduction, which possibly influenced survivorship of young.     

mRNA decapping is promoted by an RNA-binding channel in Dcp2

Cap hydrolysis by Dcp2 is a critical step in several eukaryotic mRNA decay pathways. Processing requires access to cap-proximal nucleotides and the coordinated assembly of a decapping mRNP, but the mechanism of substrate recognition and regulation by protein interactions have remained elusive. Using NMR spectroscopy and kinetic analyses, we show that yeast Dcp2 resolves interactions with the cap and RNA body using a bipartite surface that forms a channel intersecting the catalytic and regulatory Dcp1-binding domains. The interaction with cap is weak but specific and requires binding of the RNA body to a dynamic interface. The catalytic step is stimulated by Dcp1 and its interaction domain, likely through a substrate-induced conformational change. Thus, activation of the decapping mRNP is restricted by access to 5'-proximal nucleotides, a feature that could act as a checkpoint in mRNA metabolism.     

Annual use of water sources by reintroduced Rocky Mountain bighorn sheepOvis canadensis canadensis: effects of season and drought

Water sources are important for the conservation and management of bighorn sheepOvis canadensis (Shaw, 1804). Little is known, however, regarding the use of water by reintroduced Rocky Mountain bighornsO. c. canadensis (Shaw, 1804). Our purpose was to quantify use of water sources by bighorns to test hypotheses related to the value of these sites on Antelope Island, Utah, USA, from July 2005 to December 2006. We predicted that bighorns would increase the number and duration of visits to water during summer. Moreover, we predicted that animals would visit and spend more time at water during drought. Our results indicate that bighorns visited and spent more time around water in summer. These animals, however, did not visit and spend more time at water during drought. Nevertheless, use of water sources increased during times of similar precipitation that followed drought, indicating a potential time-lag in water use by bighorns. Our results underscore the importance of water for reintroduced bighorns in the deserts of western USA, and indicate that animals congregate in riparian areas near water and thereby may facilitate the spreading of diseases and parasites.     

Survival of resident and translocated greater sage-grouse in Strawberry Valley,Utah: A 13-year study

Survival of greater sage-grouse (Centrocercus urophasianus) has been well described in large populations across the species range. Very little published information exists, however, on survival rates of translocated sage-grouse or grouse from a long-term (>10 yr) study. Our objectives were to estimate seasonal and annual survival rates; assess differences in survival between resident and translocated, adult and yearling, and male and female sage-grouse; identify environmental and behavioral factors associated with survival; and assess the influence of mammalian predator control on survival rates of radio-marked sage-grouse in Strawberry Valley, Utah from 1998 to 2010. We used a 2-stage model selection approach using Akaike's Information Criterion corrected for sample size (AIC_c) with known-fate models in Program MARK to evaluate the influences of seasonal, annual, demographic, and behavioral effects on survival rates of sage-grouse. We captured and fitted 535 individual sage-grouse (male and female, resident and translocated) with radio transmitters over a 13-year period and monitored them weekly. The top model of survival, which accounted for 22% of the AIC_c weight, included 3 seasons that varied by year where rates were influenced by residency, sex, and whether a female initiated a nest. A group-level covariate for the number of canids killed each year received some support as this variable improved model fit compared to identical models without it, although confidence intervals around β estimates overlapped zero slightly. All other demographic or environmental variables showed little or no support. Annual estimates of survival for females ranged between 28% and 84% depending on year and translocation source. Survival was consistently highest during the fall–winter months with a mean monthly survival rate of 0.97 (95% CI = 0.96–0.98). The lack of a control site and other potential confounding factors limit the extent of our inference with respect to predator control. Nonetheless, we suggest managers consider enhancing nesting habitat, translocating sage-grouse, and possibly controlling predators to improve survival rates of sage-grouse. © The Wildlife Society, 2013     

The effect of a side chain-backbone swap on protein stability.

To assess the relative importance of backbone hydrogen bonding (H-bonding) vs. side chain hydrophobicity in protein structural formation, a method called side chain-backbone swap is proposed. Such a method swaps the side chain and backbone portions of certain amino acid residues, such as Asp, Glu, Asn, Gln, Lys, and Arg. Such a swap retains the sequence of a polypeptide and preserves the identity of the backbone linkage. On the other hand, the swap disrupts backbone H-bonding geometry because of the introduction of extra methylene groups into the peptide backbone. In this project, we chose the two-stranded alpha-helical coiled-coil to implement side chain-backbone swap. A pair of 36-residue peptides was designed. The two peptides have identical sequence with four residues in each heptad repeat occupied by glutamyl residues. Each glutamic acid was incorporated either as alpha-glutamyl residue (the peptide is denoted as alpha-Glu-36) or as gamma-glutamyl residue (the peptide is denoted as gamma-Glu-36). The inter-conversion between the two peptides constitutes a side chain-backbone swap. Residues constituting the hydrophobic core of the coiled-coil, however, are left unchanged. The peptide pair was characterized by circular dichroism spectroscopy, reversed-phase liquid chromatography (RPLC), and two-dimensional nuclear magnetic resonance (NMR). The results indicate that alpha-Glu-36 is a two-stranded alpha-helical coiled-coil while gamma-Glu-36 lacks stable structural elements. It is concluded that, at least for coiled-coils where hydrophobic interactions are predominantly long-range, local backbone H-bonding is a required for structural formation, consistent with a hierarchic folding mechanism. The methodological implication of side chain-backbone swap is also discussed.