Extracellular Signal-regulated Kinase Mediates Expression of Arginase II but Not Inducible Nitric-oxide Synthase in Lipopolysaccharide-stimulated Macrophages

The mitogen-activated protein kinases (MAPK) have been shown to participate in iNOS induction following lipopolysaccharide (LPS) stimulation, while the role of MAPKs in the regulation of arginase remains unclear. We hypothesized that different MAPK family members are involved in iNOS and arginase expression following LPS stimulation. LPS-stimulated RAW 264.7 cells exhibited increased protein and mRNA levels for iNOS, arginase I, and arginase II; although the induction of arginase II was more robust than that for arginase I. A p38 inhibitor completely prevented iNOS expression while it only attenuated arginase II induction. In contrast, a MEK1/2 inhibitor (ERK pathway) completely abolished arginase II expression while actually enhancing iNOS induction in LPS-stimulated cells. Arginase II promoter activity was increased by ∼4-fold following LPS-stimulation, which was prevented by the ERK pathway inhibitor. Arginase II promoter activity was unaffected by a p38 inhibitor or JNK pathway interference. Transfection with a construct expressing a constitutively active RAS mutant increased LPS-induced arginase II promoter activity, while transfection with a vector expressing a dominant negative ERK2 mutant or a vector expressing MKP-3 inhibited the arginase II promoter activity. LPS-stimulated nitric oxide (NO) production was increased following siRNA-mediated knockdown of arginase II and decreased when arginase II was overexpressed. Our results demonstrate that while both the ERK and p38 pathways regulate arginase II induction in LPS-stimulated macrophages, iNOS induction by LPS is dependent on p38 activation. These results suggest that differential inhibition of the MAPK pathway may be a potential therapeutic strategy to regulate macrophage phenotype.     

Evolution of risk‐taking during conspicuous mating displays

In many species, males possess conspicuous characteristics to attract females. These traits often attract predators as well, and males thus may have to balance the conspicuousness of their signals in relation to the prevailing predation risk. Here we develop a theoretical model of optimal signaling and risk‐taking behavior for males differing in the attractiveness of their signals. All else being equal, more attractive males should behave more cautiously. Yet this prediction may drastically change if males differ in any additional characteristic, especially if basal mortality rate or signaling costs are higher or if the vulnerability to predators is lower for attractive males. A key insight from our model is that male competition will create a positive feedback so that selection on male risk‐taking strategies is acting in opposite directions. If selection acts on one male type to behave more cautiously, this will strengthen selection on males of the other types to take higher risks and vice versa. Our results further demonstrate that the asset‐protection principle, which states that individuals with higher future expectations should behave more cautiously, may often be violated. We also offer an alternative to the handicap principle explaining the often found positive association between male ornamentation and viability: attractive males may simply behave more cautiously.     

Nitrosylmyoglobin as antioxidant--kinetics and proposed mechanism for reduction of hydroperoxides

Nitrosylmyoglobin (MbFe^IINO), which is believed to have a protective role during ischemia and reperfusion injury, was oxidized by tert-butyl hydroperoxide (t-BuOOH), and by hydrogen peroxide (H₂O₂) to the nitrite anion and metmyoglobin (MbFe^III). Further characterization of the reaction of MbFe^IINO with excess of t-BuOOH was investigated with respect to reaction stoichiometry, temperature and pH dependence. It was found that the reaction between MbFe^IINO with excess of t-BuOOH followed a simple stoichiometry and had moderate pH and temperature dependence with the activation parameters ΔH^‡ = 57.4 ± 1.4 kJ mol^- 1 and ΔS^‡ = - 112.0 ± 5.1 J mol^- 1 K^- 1, which is consistent with an associative reaction mechanism. Moreover, t-BuOOH-induced oxidation of MbFe^IINO did not result in any detectable formation of the hypervalent myoglobin (Mb) species, i.e. perferrylmyoglobin, (^√MbFe^IV = O) or ferrylmyoglobin (MbFe^IV = O), and hereby differed from H₂O₂-induced oxidation of MbFe^IINO, which results in the formation of MbFe^IV = O. Based on the obtained results and on published data, different mechanisms for the reaction of the MbFe^IINO with t-BuOOH and H₂O₂ are proposed.     

Sex matters: Otolith shape and genomic variation in deacon rockfish (Sebastes diaconus)

Little is known about intraspecific variation within the deacon rockfish (Sebastes diaconus), a recently described species found in the northeast Pacific Ocean. We investigated population structure among fish sampled from two nearshore reefs (Siletz Reef and Seal Rock) and one offshore site (Stonewall Bank) within a <50‐km² area off the Oregon coast. Fish from the three sample sites exhibited small but statistically significant differences based on genetic variation at >15,000 neutral loci, whether analyzed independently or classified into nearshore and offshore groups. Male and females were readily distinguished using genetic data and 92 outlier loci were associated with sex, potentially indicating differential selection between males and females. Morphometric results indicated that there was significant secondary sexual dimorphism in otolith shape, but further sampling is required to disentangle potential confounding influence of age. This study is the first step toward understanding intraspecific variation within the deacon rockfish and the potential management implications. Since differentiation among the three sample sites was small, we consider the results to be suggestive of a single stock. However, future studies should evaluate how the stock is affected by differences in sex, age, and gene flow between the nearshore and offshore environments.     

Survival rates and causes of mortality of roe deer <Emphasis Type="Italic">Capreolus capreolus</Emphasis> in a rural landscape,eastern Poland

Game species in the cultural landscapes of Europe are exposed to several sources of anthropogenic pressure. Whilst hunting is part of coordinated wildlife management, poaching is difficult to quantify, and hence, relatively little is known about its impact on survival patterns of game species. We estimated survival and cause-specific mortality rates of 31 roe deer Capreolus capreolus in the surroundings of the Bia?owie?a Primeval Forest, eastern Poland, from 2010 to 2013. The study area consisted of large, extensively used agricultural fields and a mosaic of pine plantations, which were interspersed with natural forest stands and small agricultural fields and meadows. Roe deer were regularly hunted and the forested part of the study area was traversed by large carnivores. Annual survival rate of all deer was 0.69 and did not differ between seasons. Annual survival rates of females and males in each age class (young and adult) were similar. Poaching was a major source of mortality (6 out of 13 roe deer deaths), and poachers did not prefer any sex or age. Adult survival (0.77) was higher than survival of young individuals (0.53); this trend was stronger when poaching was excluded from the analysis. All cases of poaching were recorded between mid-September and February. Although the two parts of the study area were exposed to a similar degree of anthropogenic pressure, all poached individuals occupied home ranges in the mosaic, where the forest cover in home ranges of roe deer was significantly higher than in the field.     

Aspicilia goettweigensis (Megasporaceae,lichenized Ascomycetes) – a poorly known and overlooked species in Europe and Russia

Aspicilia goettweigensis is a poorly known species from xerothermic siliceous rocks in Europe. It is considered to be common in the Czech Republic and it is new to Hungary and Russia. The main diagnostic character is formation of cracked, popcorn‐like, areoles in the central parts of the thalli. Analysis of nrITS sequences revealed its close relationship to Aspicilia subdepressa and A. volcanica. TLC revealed stictic acid in analysed A. goettweigensis samples. A key to non‐lobate Aspicilia with stictic acid known from Europe is provided.     

Estrogenic and progestogenic effects of hormonal contraceptives in relation to sexual behavior: insights into extended sexuality

Women's mating adaptations may vary between fertile and luteal phases, given different costs and benefits of sexual activity during each phase. Women's non-conceptive (“extended”) sexuality might function in the context of pair-bonding. The current studies examined associations between women's loyalty and faithfulness to their relationships and frequency of sexual intercourse in women using hormonal contraception. As predicted, in study 1 estimated levels (adjusted for potency) of both synthetic estrogen and progestin delivered to women moderated the association between women's loyalty/faithfulness to their partner and frequency of intercourse: as estradiol levels diminished, and progestin levels increased, women's loyalty/faithfulness became more positively associated with frequency of intercourse. Study 2 replicated these findings in a sample of women studied over a 12 week period. Results further support claims for a possible function of extended sexuality, and speak to hormonal mechanisms affecting it. They also have important methodological and applied implications.     

Cascading effects of mass mortality events in Arctic marine communities

Mass mortality events caused by pulse anthropogenic or environmental perturbations (e.g., extreme weather, toxic spills or epizootics) severely reduce the abundance of a population in a short time. The frequency and impact of these events are likely to increase across the globe. Studies on how such events may affect ecological communities of interacting species are scarce. By combining a multispecies Gompertz model with a Bayesian state‐space framework, we quantify community‐level effects of a mass mortality event in a single species. We present a case study on a community of fish and zooplankton in the Barents Sea to illustrate how a mass mortality event of different intensities affecting the lower trophic level (krill) may propagate to higher trophic levels (capelin and cod). This approach is especially valuable for assessing community‐level effects of potential anthropogenic‐driven mass mortality events, owing to the ability to account for uncertainty in the assessed impact due to uncertainty about the ecological dynamics. We hence quantify how the assessed impact of a mass mortality event depends on the degree of precaution considered. We suggest that this approach can be useful for assessing the possible detrimental outcomes of toxic spills, for example oil spills, in relatively simple communities such as often found in the Arctic, a region under increasing influence of human activities due to increased land and sea use.     

A Chromosome-Level Assembly of Blunt Snout Bream (Megalobrama amblycephala) Genome Reveals an Expansion of Olfactory Receptor Genes in Freshwater Fish

The number of olfactory receptor genes (ORs), which are responsible for detecting diverse odor molecules varies extensively among mammals as a result of frequent gene gains and losses that contribute to olfactory specialization. However, how OR expansions/contractions in fish are influenced by habitat and feeding habit and which OR subfamilies are important in each ecological niche is unknown. Here, we report a major OR expansion in a freshwater herbivorous fish, Megalobrama amblycephala, using a highly contiguous, chromosome-level assembly. We evaluate the possible contribution of OR expansion to habitat and feeding specialization by comparing the OR repertoire in 28 phylogenetically and ecologically diverse teleosts. In total, we analyzed > 4,000 ORs including 3,253 intact, 122 truncated, and 913 pseudogenes. The number of intact ORs is highly variable ranging from 20 to 279. We estimate that the most recent common ancestor of Osteichthyes had 62 intact ORs, which declined in most lineages except the freshwater Otophysa clade that has a substantial expansion in subfamily β and ε ORs. Across teleosts, we found a strong association between duplications of β and ε ORs and freshwater habitat. Nearly, all ORs were expressed in the olfactory epithelium (OE) in three tested fish species. Specifically, all the expanded β and ε ORs were highly expressed in OE of M. amblycephala. Together, we provide molecular and functional evidence for how OR repertoires in fish have undergone gain and loss with respect to ecological factors and highlight the role of β and ε OR in freshwater adaptation.