Open stomata 1 (OST1) kinase controls R–type anion channel QUAC1 in Arabidopsis guard cells

Under drought stress, the stress hormone ABA addresses the SnR kinase OST1 via its cytosolic receptor and the protein phosphatase ABI1. Upon activation, OST1 phosphorylates the guard cell S–type anion channel SLAC1. Arabidopsis ABI1 and OST1 loss‐of‐function mutants are characterized by an extreme wilting 'open stomata′ phenotype. Given the fact that guard cells express both SLAC‐ and R–/QUAC‐type anion channels, we questioned whether OST1, besides SLAC1, also controls the QUAC1 channel. In other words, are ABI1/OST1 defects preventing both of the guard cell anion channel types from operating properly in terms of stomatal closure? The activation of the R–/QUAC‐type anion channel by ABA signaling kinase OST1 and phosphatase ABI1 was analyzed in two experimental systems: Arabidopsis guard cells and the plant cell‐free background of Xenopus oocytes. Patch‐clamp studies on guard cells show that ABA activates R–/QUAC‐type currents of wild‐type plants, but to a much lesser extent in those of abi1–1 and ost1–2 mutants. In the oocyte system the co‐expression of QUAC1 and OST1 resulted in a pronounced activation of the R–type anion channel. These studies indicate that OST1 is addressing both S–/SLAC‐ and R–/QUAC‐type guard cell anion channels, and explain why the ost1–2 mutant is much more sensitive to drought than single slac1 or quac1 mutants.     

Fine Structure of the Plasmodia and Myxospore of Ellipsomyxa gobioides n. sp. (Myxozoa) Found in the Gallbladder of Gobioides broussonnetii (Teleostei: Gobiidae) from the Lower Amazon River

A fish infecting myxosporean Ellipsomyxa gobioides n. sp. is described in the gallbladder of the Amazonian dragon fish Gobioides broussonnetii. Irregular disporous plasmodia (up to ~30 μm in diameter) with long branched and anastomosed pseudopodia were found attached to the gallbladder wall. Mature ellipsoid myxospores occurring floating in the bile measured 6.8 (6.5–7.0) μm (n = 30) long, 7.2 (6.9–7.5) μm (n = 15) wide, and 13.1 (12.8–13.5) (n = 25) thick. They had smooth thin valves elongated in the direction perpendicular to the plane of the straight central transverse sutural line. The two ellipsoidal polar capsules (PC) opened some distance from the sutural line on opposite sides, each measuring 4.6 (4.3–4.8) μm (n = 15) long and 2.5 (2.1–2.7) μm (n = 20) wide. Distance between PC 3.5 (3.1–3.8) μm (n = 15) in apical view. The polar filament was isofilar and consisted of a single coil with five or six turns. The objective of this study was to characterize this new species based on its morphological differences from the three previously described species. This is the first reported species of genus Ellipsomyxa from among the South American fauna.     

Thermal controls of Yellowstone cutthroat trout and invasive fishes under climate change

We combine large observed data sets and dynamically downscaled climate data to explore historic and future (2050–2069) stream temperature changes over the topographically diverse Greater Yellowstone Ecosystem (elevation range = 824–4017 m). We link future stream temperatures with fish growth models to investigate how changing thermal regimes could influence the future distribution and persistence of native Yellowstone cutthroat trout (YCT) and competing invasive species. We find that stream temperatures during the recent decade (2000–2009) surpass the anomalously warm period of the 1930s. Climate simulations indicate air temperatures will warm by 1 °C to >3 °C over the Greater Yellowstone by mid‐21st century, resulting in concomitant increases in 2050–2069 peak stream temperatures and protracted periods of warming from May to September (MJJAS). Projected changes in thermal regimes during the MJJAS growing season modify the trajectories of daily growth rates at all elevations with pronounced growth during early and late summer. For high‐elevation populations, we find considerable increases in fish body mass attributable both to warming of cold‐water temperatures and to extended growing seasons. During peak July to August warming, mid‐21st century temperatures will cause periods of increased thermal stress, rendering some low‐elevation streams less suitable for YCT. The majority (80%) of sites currently inhabited by YCT, however, display minimal loss (<10%) or positive changes in total body mass by midcentury; we attribute this response to the fact that many low‐elevation populations of YCT have already been extirpated by historical changes in land use and invasions of non‐native species. Our results further suggest that benefits to YCT populations due to warmer stream temperatures at currently cold sites could be offset by the interspecific effects of corresponding growth of sympatric, non‐native species, underscoring the importance of developing climate adaptation strategies that reduce limiting factors such as non‐native species and habitat degradation.     

Polymorphism of lectin genes in Lathyrus plants

The carbohydrate-binding sequences of the lectin genes from spring vetchling Lathyrus vernus (L.) Bernh., marsh vetchling L. palustris (L.), and Gmelin's vetchling L. gmelinii (Fitsch) (Fabaceae) were determined. Computer-aided analysis revealed substantial differences between nucleotide and predicted amino acid sequences of the lectin gene regions examined in each of the three vetchling species tested. In the phylogenetic trees based on sequence similarity of carbohydrate-biding regions of legume lectins, the sequences examined formed a compact cluster with the lectin genes of the plants belonging to the tribe Fabeae. In each plant, L. vernus, L. palustris, and L. gmelinii, three different lectin-encoding genes were detected. Most of the substitutions were identified within the gene sequence responsible for coding the carbohydrate-binding protein regions. This finding may explain different affinity of these lectins to different carbohydrates, and as a consequence, can affect the plant host specificity upon development of symbiosis with rhizobium bacteria.     

Cues to sex- and stress-hormones in the human male face: functions of glucocorticoids in the immunocompetence handicap hypothesis

The stress-linked version of the immunocompetence handicap hypothesis has been proposed to account for inconsistencies in relationships between testosterone and immune response. The model has received some support from studies demonstrating roles of stress hormones in relationships between testosterone, immune function and secondary sexual ornamentation. Such work, however, has relied on artificial elevation of testosterone so may not reflect relationships in natural populations. We created human male facial stimuli on the basis of naturally co-occurring levels of salivary testosterone and the stress hormone cortisol. In Study 1 we tested female preferences for male faces with cues to combinations of the hormones across the menstrual cycle, and in Study 2 we tested perceptions of health and dominance in a novel set of facial stimuli. Females preferred cues to low cortisol, a preference that was strongest during the fertile phase of the menstrual cycle. The effects of cortisol on attractiveness and perceived health and dominance were contingent upon level of testosterone: the effects of the stress hormone were reduced when testosterone was high. We propose explanations for our results, including low cortisol as a cue to a heritable component of health, attractiveness as a predictor of low social-evaluative threat (and, therefore, low baseline cortisol) and testosterone as a proxy of male ability to cope efficiently with stressors.     

Phylogeography and evolutionary history of reassortant H9N2 viruses with potential human health implications

Avian influenza viruses of the H9N2 subtype have seriously affected the poultry industry of the Far and Middle East since the mid-1990s and are considered one of the most likely candidates to cause a new influenza pandemic in humans. To understand the genesis and epidemiology of these viruses, we investigated the spatial and evolutionary dynamics of complete genome sequences of H9N2 viruses circulating in nine Middle Eastern and Central Asian countries from 1998 to 2010. We identified four distinct and cocirculating groups (A, B, C, and D), each of which has undergone widespread inter- and intrasubtype reassortments, leading to the generation of viruses with unknown biological properties. Our analysis also suggested that eastern Asia served as the major source for H9N2 gene segments in the Middle East and Central Asia and that in this geographic region within-country evolution played a more important role in shaping viral genetic diversity than migration between countries. The genetic variability identified among the H9N2 viruses was associated with specific amino acid substitutions that are believed to result in increased transmissibility in mammals, as well as resistance to antiviral drugs. Our study highlights the need to constantly monitor the evolution of H9N2 viruses in poultry to better understand the potential risk to human health posed by these viruses.     

Disruption of the murine procollagen C-proteinase enhancer 2 gene causes accumulation of pro-apoA-I and increased HDL levels

Given the increased prevalence of cardiovascular disease in the world, the search for genetic variations that impact risk factors associated with the development of this disease continues. Multiple genetic association studies demonstrate that procollagen C-proteinase enhancer 2 (PCPE2) modulates HDL levels. Recent studies revealed an unexpected role for this protein in the proteolytic processing of pro-apolipoprotein (apo) A-I by enhancing the cleavage of the hexapeptide extension present at the N-terminus of apoA-I. To investigate the role of the PCPE2 protein in an in vivo model, PCPE2-deficient (PCPE2 KO) mice were examined, and a detailed characterization of plasma lipid profiles, apoA-I, HDL speciation, and function was done. Results of isoelectric focusing (IEF) electrophoresis together with the identification of the amino terminal peptides DEPQSQWDK and WHVWQQDEPQSQWDVK, representing mature apoA-I and pro-apoA-I, respectively, in serum from PCPE2 KO mice confirmed that PCPE2 has a role in apoA-I maturation. Lipid profiles showed a marked increase in plasma apoA-I and HDL-cholesterol (HDL-C) levels in PCPE2 KO mice compared with wild-type littermates, regardless of gender or diet. Changes in HDL particle size and electrophoretic mobility observed in PCPE2 KO mice suggest that the presence of pro-apoA-I impairs the maturation of HDL. ABCA1-dependent cholesterol efflux is defective in PCPE2 KO mice, suggesting that the functionality of HDL is altered.     

Reproductive biology and implications for management of the painted sweetlips Diagramma pictum in the southern Arabian Gulf

The reproductive biology of the painted sweetlips Diagramma pictum was determined from 487 individuals collected between January and December 2010 in the southern Arabian Gulf. There was no evidence of sex change and the combination of histological results with the sex composition of the size and age structures indicated a gonochoristic sexual pattern. There were peaks in gonado-somatic indices for females in March and October with spawning occurring during two seasons (April to May and November). The mean size and age at sexual maturity (L(m50) and A(m50) ) were 35·7 cm fork length (L(F) ) and 2·9 years for females and 26·7 cm L(F) and 0·5 years for males. The maximum recorded age (11 years) and small mean size and young age at sexual maturity for males may be a direct result of intensive demersal fishing in the southern Arabian Gulf. There was an exponential increase in the cumulative reproductive potential with size and a linear increase with age for both sexes. The mean L(F) (L(c50) ) at which D. pictum became vulnerable to capture was 33·3 cm, which corresponded to only 3 and 7% of the cumulative reproductive potential of males and females, respectively. Size-specific and age-specific reproductive potential indicated that conventional regulations that equate the mean size at first capture to sexual maturation are unsuitable for the management of D. pictum.     

Comparison of the Diversilab® system with multi-locus sequence typing and pulsed-field gel electrophoresis for the characterization of Streptococcus agalactiae invasive strains

Streptococcus agalactiae (or group B streptococcus; GBS) is a leading cause of neonatal morbidity and mortality in the developed countries. Several epidemiological typing tools have been developed for GBS to investigate the association between genotype and disease and to assess genetic variations within genogroups. This study compared the semi-automated repetitive sequence-based PCR Diversilab® system (DL) with MLST and pulsed field gel electrophoresis (PFGE) for determining the relatedness of invasive GBS strains. We analysed 179 unrelated GBS strains isolated from adult (n = 108) and neonatal (n = 71) invasive infections. By MLST, strains were resolved into 6 clonal complexes (CCs) including 23 sequence-types (STs), and 4 unique STs, whereas DL differentiated these isolates into 12 rep-PCR clusters (rPCs) and 9 unique rep-PCR types. The discriminatory power of both methods was similar, with Simpson's diversity indexes of 71.9% and 70.6%, respectively. However, their clustering concordance was low with Wallace concordance coefficients inferior to 0.4. PFGE was performed on 31 isolates representative of the most relevant DLrPCs clustered within the 3 major MLST CCs (CC-17, CC-23 and CC-1). As already observed with MLST, the concordance of DL with PFGE was low for all three CCs (Wallace coefficient < 0.5), PFGE being more discriminative than rep-PCR. In summary, this work suggests that DL is less appropriate than MLST or PFGE to study GBS population genetic diversity.