Phylogeny and taxonomy of the genus Ilyodon Eigenmann, 1907 (Teleostei: Goodeidae), based on mitochondrial and nuclear DNA sequences

Taxonomy of the live‐bearing fish of the genus Ilyodon Eigenmann, 1907 (Goodeidae), in Mexico, is controversial, with morphology and mitochondrial genetic analyses in disagreement about the number of valid species. The present study accumulated a comprehensive DNA sequences dataset of 98 individuals of all Ilyodon species and mitochondrial and nuclear loci to reconstruct the evolutionary history of the genus. Phylogenetic inference produced five clades, one with two sub‐clades, and one clade including three recognized species. Genetic distances in mitochondrial genes (cytb: 0.5%–2.1%; coxI: 0.5%–1.1% and d‐loop: 2.3%–10.2%) were relatively high among main clades, while, as expected, nuclear genes showed low variation (0.0%–0.2%), with geographic concordance and few shared haplotypes among river basins. High genetic structure was observed among clades and within basins. Our genetic analyses, applying the priority principle, suggest the recognition only of Ilyodon whitei and Ilyodon furcidens, with I. cortesae relegated to an invalid species, the populations of which belong to I. whitei.     

Genetic favouring of pheomelanin‐based pigmentation limits physiological benefits of coloniality in lesser kestrels Falco naumanni

Pheomelanin contributes to the pigmentation phenotype of animals by producing orange and light brown colours in the integument. However, pheomelanin synthesis in melanocytes requires consumption of glutathione (GSH), the most important intracellular antioxidant. Therefore, a genetic control favouring the production of large amounts of pheomelanin for pigmentation may lead to physiological costs under environmental conditions that promote oxidative stress. We investigated this possibility in the context of breeding coloniality, a reproductive strategy that may affect oxidative stress. We found in lesser kestrel Falco naumanni nestlings that the GSH:GSSG ratio, which decreases with systemic oxidative stress, increased with the size of the colony where they were reared, but the expression in feather melanocytes of five genes involved in pheomelanin synthesis (Slc7a11, Slc45a2, CTNS, MC1R and AGRP) did not vary with colony size. The antioxidant capacity (TEAC) of lesser kestrel nestlings also increased with colony size, but in a manner that depended on Slc7a11 expression and not on the expression of the other genes. Thus, antioxidant capacity increased with colony size only in nestlings least expressing Slc7a11, a gene with a known role in mediating cysteine (a constituent amino acid of GSH) consumption for pheomelanin production. The main predictor of the intensity of pheomelanin‐based feather colour was Slc45a2 expression followed in importance by Slc7a11 expression, hence suggesting that the genetic regulation of the pigmentation phenotype mediated by Slc7a11 and a lack of epigenetic lability in this gene limits birds from benefiting from the physiological benefits of coloniality.     

No evidence for costs of being large in females of Orgyia spp. (Lepidoptera, Lymantriidae): larger is always better

Strong correlation between female body size and potential fecundity is often observed in insects. Directional selection favouring increased body sizes is thus predicted in the absence of opposing selection pressure. The evolutionary forces capable of counterbalancing such a 'fecundity advantage' are poorly documented. This study focuses on revealing the costs of large body size in the wingless females of Orgyia antiqua and O. leucostigma, two related species of lymantriid moths. Extreme behavioural simplicity of these animals allows systematic assessment of various fitness components in conditions that are close to natural. A linear relationship between pupal weight and potential fecundity was observed. This association was found to be independent of particular rearing conditions. There was no evidence that the relationship between fecundity and body mass becomes asymptotic when body sizes increases. No component of fitness showed a negative phenotypic correlation with body size; some displayed a weakly positive one. In particular, pupal mortality, adult longevity, mating and oviposition success, as well as egg hatching rate and egg size, were established as independent of body size in a series of field and laboratory experiments. There was a very high overall efficiency of converting resources accumulated during the larval stage to egg masses. With no costs of large adult size, selective forces balancing the fecundity advantage should operate in the course of immature development. The strong dependence of realized fecundity on body size is considered characteristic of the capital breeding strategy.     

Characterisation of the lowest singlet and triplet excited states of S-flurbiprofen.

The photophysical properties of S-flurbiprofen [S-2-fluoro-alpha-methyl-4-biphenylacetic acid], a nonsteroidal anti-inflammatory drug, have been examined using steady-state and time-resolved spectroscopic techniques. The energy of its first singlet excited state is 99 kcal mol(-1). The fluorescence quantum yields and lifetimes (at 300 nm) have been determined in acetonitrile, methanol, hexane and PBS; they are in the range 0.15相似文献   

Cell Surface Glycosaminoglycans As Receptors for Adhesion of Candida Spp. To Corneal Cells

The most common causal agents of fungal keratitis are yeasts of the Candida genus. Adhesion constitutes the first stage of pathogenesis. Previous studies have shown that glycosaminoglycans from the corneal cell surface play an essential role in bacterial keratitis, although little is known about their role in fungal infections. The objective of this work is to analyze the role that glycosaminoglycans (GAGs) play in the adhesion of fungi of the Candida genus to corneal epithelial cells. The participation of GAGs in the adhesion of fungi was studied through the specific inhibition of the synthesis of these molecules by enzymatic digestion using specific lyases and the silencing of various genes involved in heparan sulfate sulfation. The results seem to indicate that glycosaminoglycans act to some extent as receptors for this fungus, although there are differences between fungal species. Treatment with inhibitors partially reduced the adherence of fungal species. Digestion of cell surface heparan sulfate further reduced the adherence of Candida albicans and Candida glabrata compared to chondroitin sulfate, indicating that the binding is preferentially mediated by heparan sulfate. Degradation of both heparan sulfate and chondroitin sulfate produced similar effects on the adherence of Candida parapsilosis. However, adhesion of C. albicans hyphae is not dependent on GAGs, suggesting the expression of other adhesins and the recognition of other receptors present in corneal cells. Our results open the door to new strategies for stopping the adhesion of pathogenic fungi, and their subsequent invasion of the cornea; thus, reducing the probability of the keratitis development.     

Multiresistant Enterobacteriaceae in yellow‐legged gull chicks in their first weeks of life

Wild animal species living in anthropogenic areas are commonly carriers of antimicrobial‐resistant bacteria (AMRB), but their role in the epidemiology of these bacteria is unclear. Several studies on AMRB in wildlife have been cross‐sectional in design and sampled individual animals at only one point in time. To further understand the role of wildlife in maintaining and potentially transmitting these bacteria to humans and livestock, longitudinal studies are needed in which samples are collected from individual animals over multiple time periods. In Europe, free‐ranging yellow‐legged gulls (Larus michahellis) commonly live in industrialized areas, forage in landfills, and have been found to carry AMRB in their feces. Using bacterial metagenomics and antimicrobial resistance characterization, we investigated the spatial and temporal patterns of AMRB in a nesting colony of yellow‐legged gulls from an industrialized area in southern France. We collected 54 cloacal swabs from 31 yellow‐legged gull chicks in 20 nests on three dates in 2016. We found that AMRB in chicks increased over time and was not spatially structured within the gull colony. This study highlights the complex occurrence of AMRB in a free‐ranging wildlife species and contributes to our understanding of the public health risks and implications associated with ARMB‐carrying gulls living in anthropogenic areas.     

Ulcerative Colitis Seems to Imply Oral Microbiome Dysbiosis

Ulcerative colitis (UC) is a recurrent pathology of complex etiology that has been occasionally associated with oral lesions, but the overall composition of the oral microbiome in UC patients and its role in the pathogenesis of the disease are still poorly understood. In this study, the oral microbiome of UC patients and healthy individuals was compared to ascertain the possible changes in the oral microbial communities associated with UC. For this, the salivary microbiota of 10 patients diagnosed with an active phase of UC and 11 healthy controls was analyzed by 16S rRNA gene sequencing (trial ref. ISRCTN39987). Metataxonomic analysis revealed a decrease in the alpha diversity and an imbalance in the relative proportions of some key members of the oral core microbiome in UC patients. Additionally, Staphylococcus members and four differential species or phylotypes were only present in UC patients, not being detected in healthy subjects. This study provides a global snapshot of the existence of oral dysbiosis associated with UC, and the possible presence of potential oral biomarkers.     

Combined treatment with statins and aminobisphosphonates extends longevity in a mouse model of human premature aging

Several human progerias, including Hutchinson-Gilford progeria syndrome (HGPS), are caused by the accumulation at the nuclear envelope of farnesylated forms of truncated prelamin A, a protein that is also altered during normal aging. Previous studies in cells from individuals with HGPS have shown that farnesyltransferase inhibitors (FTIs) improve nuclear abnormalities associated with prelamin A accumulation, suggesting that these compounds could represent a therapeutic approach for this devastating progeroid syndrome. We show herein that both prelamin A and its truncated form progerin/LADelta50 undergo alternative prenylation by geranylgeranyltransferase in the setting of farnesyltransferase inhibition, which could explain the low efficiency of FTIs in ameliorating the phenotypes of progeroid mouse models. We also show that a combination of statins and aminobisphosphonates efficiently inhibits both farnesylation and geranylgeranylation of progerin and prelamin A and markedly improves the aging-like phenotypes of mice deficient in the metalloproteinase Zmpste24, including growth retardation, loss of weight, lipodystrophy, hair loss and bone defects. Likewise, the longevity of these mice is substantially extended. These findings open a new therapeutic approach for human progeroid syndromes associated with nuclear-envelope abnormalities.