Phylogenetic relationships of the endemic Antarctic benthic hydroids (Cnidaria, Hydrozoa): what does the mitochondrial 16S rRNA tell us about it?

Hydroidolinan hydrozoans are widely represented in the benthic Antarctic ecosystem, mainly by some endemic and putative monophyletic groups, never included in molecular phylogenetic analyses. 38 partial sequences of the mitochondrial 16S rRNA gene were obtained for 38 species belonging to 14 families (six anthoathecates and eight leptothecates) and 20 genera (7 anthoathecates and 13 leptothecates). These sequences were combined with 108 additional sequences retrieved from the GenBank to investigate both the hypothetical monophyletism and the phylogenetic relationships of those endemic Antarctic groups; the potential use of the marker for barcoding was also investigated. Our results uphold the monophyly of some important hydroidolinan groups, such as the superfamily Plumularioidea (together with all its families, including Schizotrichidae, fam. nov.) and the Aplanulata. Concerning the Antarctic endemic groups, most results as monophyletic (Oswaldella, Schizotricha and Staurotheca), some genera form part of the expectable groups (e.g. Abietinella, located into the monophyletic Zygophylacinae clade) and, finally, others have shown a surprising position (e.g. Stegella, closely related to Lafoeinae, or Billardia and Stegopoma, allied with Hebellidae). Finally, our study has shown the utility of the marker to recognize the Antarctic species considered, but the low genetic divergence in some of the most important Antarctic groups suggests being careful when using it for DNA barcoding in the case of the original Antarctic hydroid fauna.     

Succinic Acid Production with Actinobacillus succinogenes ZT-130 in the Presence of Succinic Acid

Glucose fermentation with Actinobacillus succinogenes was carried out at different initial concentrations of succinic acid (SA₀) to determine its effect on growth and on the production of succinic acid itself. The specific rates of biomass production, succinic, formic and acetic acids decreased with SA₀ (0–40 g/l). The partially dissociated form of succinic acid had a higher effect on cell growth and production of succinic acid as compared to the non-dissociated forms of the acids, a fact that has not been reported until now. Cell growth fitted the Jerusalimski model, and the Aiba–Shoda model was suitable for quantification of the inhibition for the production of succinic acid. The growth inhibition constants K _is and K _ip and their summatory were consistent with the experimental values obtained, i.e., 22 g/l for the produced acids and 38 g/l for total acids that were the limits at which the biomass formation ceased.     

The main factors affecting the reproductive performance of rabbit does: a review

This paper reviews the main factors affecting the reproductive performance of rabbit does. In the last 15 years the profitability of rabbit farms has increased mainly due to improvements in management and genetic selection but several problems related to animal welfare have also occurred. The replacement and the mortality rates of female per year are very high and the replaced does often show poor body condition and poor health status. The effect of kindling order, litter size, genetic strain, weaning age and reproductive rhythm on the reproductive performance and welfare of females and mechanisms implicated in these effects are discussed. The rabbit doe of modern strains produces a lot of milk with high energetic value, which leads to a mobilization of body fat resulting in a negative energy balance. In the current reproductive rhythms, there is an extensive overlap between lactation and gestation. The resulting energetic and hormonal antagonism reduces the fertility rate and lifespan of the doe. Strategies to optimize these parameters are discussed. An approach that combines various strategies seems to be required to meet these objectives. Since the factors involved in this system are predetermined (genetic strain, environment) the most powerful way to improve doe welfare is to choose a reproductive rhythm more adapted to the physiology of the does.     

On the heritability of blue‐green eggshell coloration

Abstract Avian blue‐green eggshell coloration has been proposed as a female signal of genetic or phenotypic quality to males. However, little is known about the relative importance of additive genetic and environmental effects as sources of eggshell colour variation in natural populations. Using 5 years of data and animal models, we explored these effects in a free‐living population of pied flycatchers. Permanent environmental and year effects were negligible, although year environmental variance (V_Year) was significant for all but one of the traits. However, we found high–moderate narrow‐sense heritabilities for some colour parameters. Within‐clutch colour variability showed the highest coefficient of additive genetic variation (i.e. evolvability). Previous evidence suggests that eggshell colour is sexually selected in this species, males enhancing parental effort in clutches with higher colour variability and peak values. Eggshell colour could be driven by good‐genes selection in pied flycatchers although further genetic studies should confirm this possibility.     

Signal convergence in fruits: a result of selection by frugivores?

The Dispersal Syndrome hypothesis remains contentious, stating that apparently nonrandom associations of fruit characteristics result from selection by seed dispersers. We examine a key assumption under this hypothesis, i.e. that fruit traits can be used as reliable signals by frugivores. We first test this assumption by looking at whether fruit colour allows birds and primates to distinguish between fruits commonly dispersed by birds or primates. Second, we test whether the colours of fruits dispersed by primates are more contrasting to primates than the colours of bird‐dispersed fruits, expected if fruit colour is an adaptation to facilitate the detection by seed dispersers. Third, we test whether fruit colour has converged in unrelated plant species dispersed by similar frugivores. We use vision models based on peak sensitivities of birds’ and primates’ cone cells. We base our analyses on the visual systems of two types of birds (violet and ultraviolet based) and three types of primates (trichromatic primates from the Old and the New Worlds, and a dichromatic New World monkey). Using a Discriminant Function Analysis, we find that all frugivore groups can reliably discriminate between bird‐ and primate‐dispersed fruits. Fruit colour can be a reliable signal to different seed dispersers. However, the colours of primate‐dispersed fruits are less contrasting to primates than those of bird‐dispersed fruits. Fruit colour convergence in unrelated plants is independent of phylogeny and can be better explained by disperser type, which supports the hypothesis that frugivores are important in fruit evolution. We discuss adaptive and nonadaptive hypotheses that can potentially explain the pattern we found.     

Adaptation of Staphylococcus aureus to ruminant and equine hosts involves SaPI‐carried variants of von Willebrand factor‐binding protein

Staphylococci adapt specifically to various animal hosts by genetically determined mechanisms that are not well understood. One such adaptation involves the ability to coagulate host plasma, by which strains isolated from ruminants or horses can be differentiated from closely related human strains. Here, we report first that this differential coagulation activity is due to animal‐specific alleles of the von Willebrand factor‐binding protein (vWbp) gene, vwb, and second that these vwb alleles are carried by highly mobile pathogenicity islands, SaPIs. Although all Staphylococcus aureus possess chromosomal vwb as well as coagulase (coa) genes, neither confers species‐specific coagulation activity; however, the SaPI‐coded vWbps possess a unique N‐terminal region specific for the activation of ruminant and equine prothrombin. vWbp‐encoding SaPIs are widely distributed among S. aureus strains infecting ruminant or equine hosts, and we have identified and characterized four of these, SaPIbov4, SaPIbov5, SaPIeq1 and SaPIov2, which encode vWbp^Sbo4, vWbp^Sbo5, vWbp^Seq1 and vWbp^Sov2 respectively. Moreover, the SaPI‐carried vwb genes are regulated differently from the chromosomal vwb genes of the same strains. We suggest that the SaPI‐encoded vWbps may represent an important host adaptation mechanism for S. aureus pathogenicity, and therefore that acquisition of vWbp‐encoding SaPIs may be determinative for animal specificity.     

Molecular phylogeography of Carapichea ipecacuanha,an amphitropical shrub that occurs in the understory of both semideciduous and evergreen forests

The medicinal shrub Carapichea ipecacuanha (ipecac) is an amphitropic species with three disjunct areas of distribution. In the Brazilian Atlantic and Amazonian ranges, the species was associated mostly with the understory of seasonal semideciduous forests, whereas in the Central American–Colombian range, the species occurred in the understory of moist evergreen forests. We examined the phylogeographic structure of ipecac using chloroplast trnT‐trnL and nuclear internal transcribed spacer (ITS) sequences from 120 and 46 specimens, respectively. To complement existing data on root alkaloid profiles, we used high‐performance liquid chromatography to assess the levels of emetine and cephaeline in 33 specimens from the two Brazilian ranges. The three ranges shared neither nuclear nor chloroplast haplotypes. The phylogeographic structures showed an uneven distribution of genetic diversity, sharp breaks and high levels of genetic differentiation among ranges. Our results suggest that the extant populations are descendents of at least four distinct ancestral lineages. The Atlantic ipecacs showed higher levels of genetic diversity than ipecacs from the other two ranges; it is likely that they derive from two ancestral lineages, with long‐term persistence in that region. The Amazonian ipecacs were monomorphic with respect to the ITS and cpDNA sequences, which supports the view that there was a recent expansion from a single parental source after a strong genetic bottleneck. The existence of a fourth distinct lineage is apparent from the high levels of genetic and chemical differentiation that we identified in the Central American–Columbian ipecacs.     

Molecular evidence of the survival of subterranean amphipods (Arthropoda) during Ice Age underneath glaciers in Iceland

Two endemic groundwater arthropod crustacean species, Crangonyx islandicus and Crymostygius thingvallensis, were recently discovered on the mid‐Atlantic volcanic island of Iceland. The extent of morphological differences from closest relatives, endemism, along with the geographic isolation of Iceland and its complete coverage by glaciers 21 000 years ago, suggests that these two species have survived glaciation periods in sub‐glacial refugia. Here we provide strong support for this hypothesis by an analysis of mitochondrial genetic variation within Crangonyx islandicus. Our results show that the species is divided into several distinct monophyletic groups that are found along the volcanic zone in Iceland, which have been separated by 0.5 to around 5 million years. The genetic divergence between groups reflects geographic distances between sampling sites, indicating that divergence occurred after the colonization of Iceland. The genetic patterns, as well as the dependency of genetic variation on distances from the tectonic plate boundary and altitude, points to recent expansion from several refugia within Iceland. This presents the first genetic evidence of multicellular organisms as complex as crustacean amphipods which have survived glaciations beneath an ice sheet. This survival may be explained by geothermal heat linked to volcanic activities, which may have maintained favourable habitats in fissures along the tectonic plate boundary in Iceland during glaciations.     

Effect of dietary supplementation with yeast Saccharomyces cerevisiae on skin,serum and liver of gilthead seabream (Sparus aurata L)

The effect of dietary supplementation with Saccharomyces cerevisiae on gilthead seabream (Sparus aurata L.) was studied. Four replicates of fish (n = 6) were fed with a commercial diet containing 0 (control, no yeast added) or 10 mg per kilogram of heat-killed (30 min, 60°C) S. cerevisiae. After 4 weeks, half of the fish (two replicates) were injured and continued with the same diet. At 3 and 7 days post-wounding, samples of blood, skin mucus, skin and liver were obtained from each fish. The results showed that calcium concentrations were significantly higher (with respect to control fish) in the serum from fish sampled at 3 days post-wounding, whereas antioxidant enzymes in the skin mucus were altered after wounding (at both 3 and 7 days). Histological analyses revealed oedema, signs of inflammation and white cell recruitment together with a reduction in the epidermis layer in the wounded regions of fish fed control diet. Yeast supplementation did not change growth performance and helped maintain the normal serum calcium concentrations in wounded fish. Furthermore, a reduction in inflammation around wounds in the animals fed yeast with respect to that fed control diet was evident in the histological study. Furthermore, increased levels of stress-related gene expression in liver and skin from wounded fish were obtained. Overall, yeast supplementation seemed to be a functional and appropriate dietary additive to improve skin recovery reducing the stress resulting from wounds.     

Climate change effects on turtles of the genus Kinosternon (Testudines: Kinosternidae): an assessment of habitat suitability and climate niche conservatism

The Chelonian lineage has been exposed to several climate change events along its evolutionary history, but the rapid contemporary change in climate patterns has the potential to erode turtle populations. This study focuses on (1) evaluating the climatically suitable area available for 15 species of mud turtles of the genus Kinosternon, and on (2) assessing whether or not these species retain their ancestral climate niche. Occurrence data was collected for these species and, using the Maxent algorithm and WorldClim bioclimatic variables, suitable present and future climatic niche areas were modeled. In addition, we also carried out climatic niche similarity analyses between pairs of species to evaluate whether these conserve their climatic niche. Our models suggest that most species of Kinosternon will lose a high proportion of their suitable habitat in the future. Most mud turtle species seem to conserve their climatic niche, suggesting the prevalence of niche conservatism in the group. Our results indicate that several mud turtle species could be at severe risk of disappearing over the next few decades due to the loss of climatically suitable areas and of the conservation of their climatic niches.