Probing secretion and translocation of a β-autotransporter using a reporter single-chain Fv as a cognate passenger domain

The mechanism of protein secretion mediated by the beta-domain of the Neisseria gonorrhoeae IgA protease, a paradigm of a family of secreted polypeptides of Gram-negative bacteria called autotransporters, has been examined using a single-chain antibody (scFv) as a reporter passenger domain to monitor the translocation process. Fusion of a scFv to the beta-module of the IgA protease allowed us to investigate the passage of the chimeric protein through the periplasm, its insertion into the outer membrane and the movement of the N-terminal moiety towards the cell surface. As the binding activity of the scFv to its target antigen is entirely dependent on the formation of disulphide bonds, the relationship between secretion, folding and formation of S-S bridges could be analysed in detail. In contrast to the current notion that only an unfolded N-passenger domain can be translocated through the beta-domain, our results show that the scFv is able to pass through the outer membrane, albeit at a threefold reduced level, in an active conformation with its disulphide bonds preformed in the periplasm through the action of the DsbA product. These data call for a re-evaluation of the prevailing model for secretion of the N-domain of autotransporters.     

New information about <Emphasis Type="Italic">Irajatherium hernandezi</Emphasis> Martinelli,Bonaparte, Schultz &; Rubert 2005 (Eucynodontia,Tritheledontidae) from the upper triassic (Caturrita Formation,Paraná Basin) of Brazil

In this contribution, new specimens of the tritheledontid eucynodont Irajatherium hernandezi, from the Late Triassic (Caturrita Formation) of southern Brazil, are analyzed. The new material provides significant information about incisor count, canine size and shape, basicranial morphology, and other previously unknown aspects of skull and dentition. A cladistic analysis with inclusion of the new data supports the assignment of Irajatherium to Tritheledontidae, basal to Chalimininae and Pachygenelinae. Previously unknown characters of Irajatherium revealed by the new material include: the presence of three lower incisors; the first lower incisor is enlarged; the presence of large upper and lower canines with deep paracanine fossa on the maxilla; almost complete upper and lower postcanine tooth row with a pattern similar to that of other tritheledontids (e.g. Pachygenelus and Chaliminia); there is a conspicuous crest on the inner surface of the maxilla for the attachment of the inferred maxillary turbinates; partially confluent jugular foramen and fenestra rotunda within the jugular fossa, separated by a finger-like projection of the posterolateral wall of the opisthotic; and hypoglossal foramina located outside the jugular fossa. Irajatherium is a key taxon for understanding the early evolution of ictidosaurs, a group of cynodonts closely related to mammaliaforms, during the cynodont–mammal transition from the Late Triassic to Early Jurassic.     

Bearded capuchin (Sapajus libidinosus) predation on a rock cavy (Kerodon rupestris) followed by prey sharing

Primates - We describe predation on an adult rodent rock cavy and sharing of the carcass by a group of male bearded capuchins. Despite many studies, such an interaction has never been observed in...     

The cost of producing a sexual signal: testosterone increases the susceptibility of male lizards to ectoparasitic infestation

According to current evolutionary theory, advertising traitsthat honestly indicate an organism's genetic quality might becostly to produce or maintain, though the kind of costs involvedin this process are controversial. Recently the immunocompetencehypothesis has proposed that testosterone (T) stimulates theexpression of male sexually selected traits while decreasingimmunocompetence. Even though some recent studies have shownan effect of T on ectoparasite load, the dual effect of thehormone has not been addressed in free-living populations. Herewe report results of an experiment in a free-living populationof the lizard Psammodromus algirus during the mating season.Males implanted with T had larger patches of breeding colorand behaved more aggressively than control males. In T-implantedmales, the increase in number of ticks during the mating seasonwas significantly higher than in control males and this negativelyaffected several hematological parameters. T-males sufferedsignificantly higher mortality than control males during theexperiment The results from the manipulation of T are consistentwith the dual effect of this hormone.     

Familienaufl?sung und Abzug aus dem Winterquartier beim KranichGrus grus

Zusammenfassung Während des Winteraufenthalts auf der Iberischen Halbinsel nimmt beim Kranich der Familienzusammenhalt gegen Frühjahr zu stetig ab. Zunehmende Erfahrung und Geschicklichkeit im Nahrungserwerb macht die Jungvögel allmählich von ihren Eltern unabhängig. In der Regel brechen juv. nach den ad. in Richtung Brutheimat auf.

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Family breakup and spring departure from winter quarters in the Common CraneGrus grus

Summary Family cohesion in the Common Cranes decreases steadily throughout the wintering season in the Iberian Peninsula. The increasing feeding efficiency of the yearlings allow them to be progressively more independent of their parents. As a rule, the juveniles depart towards the breeding grounds after the adults.

     

A 12-year study of fungal infections in Rio Grande do Sul,Southern Brazil

BackgroundThe number of fungal infections has increased in recent years in Rio Grande do Sul (RS), Brazil. Epidemiological studies are important for proper control of infections.AimsTo evaluate the etiology of fungal infections in patients in RS, from 2003 to 2015.MethodsThis is a retrospective and longitudinal study carried out at Mycology Department of Central Laboratory of RS; 13,707 samples were evaluated. The variables sex, age, site of infection, and etiologic agent were analyzed. Susceptibility of Candida to fluconazole was tested in isolates from samples collected in 2015 from 51 outpatients.ResultsOf the 13,707 samples, 840 cases (6.12%) of fungal infections were found and included in the analyses; female gender accounted for the 55.9% of the cases. The main fungus was Candida albicans (450 cases, 53.38%; p < 0.001). Onychomycosis was the most frequent infection in superficial mycoses. Systemic mycoses accounted for 54.05% of the cases, from which 68.8% occurred in males, mainly HIV-positive (33.11%), and the main etiologic agent in these cases was Cryptococcus neoformans (73.13%). Among 51 samples tested for susceptibility to fluconazole, 78.43% of Candida isolates were susceptible; 5.88% were susceptible in a dose-dependent manner, and 15.69% were resistant.ConclusionsC. albicans is a common cause of fungal infections in RS, accounting for half of the cases; resistance to antifungals was found in non-hospitalized patients. In addition, women seem to be more susceptible to fungal infections than men, however men show more systemic mycoses than women. The nails are the most common site of infection.     

A phylogenetic analysis of Pseudopaludicola (Anura) providing evidence of progressive chromosome reduction

Here, we present a molecular phylogenetic analysis of the Neotropical genus Pseudopaludicola focusing on species relationships including 11 of the 17 known species of Pseudopaludicola; several samples of Pseudopaludicola are not assigned to any species; and 34 terminal species as an outgroup. The study was based on the analysis of approximately 2.3 kb of the sequence of the mitochondrial 12S rRNA, tRNA^val and 16S rRNA genes through maximum parsimony and Bayesian phylogenetic reconstruction approaches. Our results showed that Pseudopaludicola is a well‐supported monophyletic group organized into four major clades and confirmed that the assemblage of species that lack T‐shaped terminal phalanges is paraphyletic with respect to the P. pusilla Group. Chromosomal data mapped on the cladogram showed a direct correlation among the four clades and observed chromosome numbers (2n = 22, 20, 18 and 16) with a progressive reduction in the chromosome number. Overall, our findings suggest that some taxonomic changes are necessary and reinforce the need for a revision of the genus Pseudopaludicola.