Fine-scale analysis of biomineralized mollusc teeth using FIB and TEM

When it comes to mineral synthesis, there is a lot we can learn from nature. Although we can synthesize a range of materials in the laboratory, the experimental conditions are often constrained to particular ranges of temperature, pH, etc. Biological systems, on the other hand, seem to be able to produce individual minerals and complex composite mineral structures under a variety of conditions, many of which are far from those applied to create their synthetic counterparts. Understanding how nature does this could provide a means to produce novel biomimetic materials with potential applications in a diverse range of fields from medicine to materials engineering

Mannitol promotes adherence of an outbreak strain of Burkholderia multivorans via an exopolysaccharide-independent mechanism that is associated with upregulation of newly identified fimbrial and afimbrial adhesins

© Society for General Microbiology, 2013. Post-print version of article deposited in accordance with SHERPA RoMEO guidelinesBurkholderia multivorans, a member of the Burkholderia cepacia complex (Bcc), is an important pathogen of the cystic fibrosis (CF) lung. Mannitol, approved as an inhaled osmolyte therapy for use in CF patients, promotes exopolysaccharide (EPS) production by the Bcc. In the present study, we investigated the role of mannitol-induced EPS in the adherence of B. multivorans. We report that mannitol promoted adherence of two representative B. multivorans strains. However, whilst this enhanced adherence was largely EPS-dependent in an environmental isolate, it was EPS-independent within a CF outbreak strain, suggesting strain-to-strain variation in adhesins. Genome sequencing of the outbreak strain enabled the identification of two distinct loci encoding putative fimbrial and afimbrial adhesins. The putative fimbriae-encoding locus was found to be widely distributed amongst clinical and environmental B. multivorans. In contrast, the locus encoding the putative afimbrial adhesin (of the filamentous haemagglutinin family, FHA) was restricted to clinical isolates. Both loci contributed to biofilm formation and mucin adherence. Furthermore, we report that mannitol promoted expression of both loci, and that the locus encoding the putative FHA-family adhesin is a key determinant of the enhanced adherence observed following growth in mannitol. Our studies provide the first characterization, to our knowledge, of B. multivorans adhesins, and in so doing highlight the strain-dependent role of EPS in the Bcc and the difficulties in assigning phenotypic traits to Bcc EPS due to the wider response to mannitol. Our observations also highlight the need to monitor the microbiological effects of inhaled mannitol therapy in Bcc-infected CF patients

Towards a better understanding of the life cycle of Trypanosoma copemani

Trypanosoma copemani has been found infecting several threatened/endangered marsupial species within Australia and is thought to be a key player in the rapid decline of the woylie (Bettongia penicillata). To better understand the biology and life cycle of this parasite, the growth requirements, and kinetics of infection of two newly described genotypes, T. copemani G1 and G2, were investigated and compared with the T. cruzi strain-10R26 in vitro. Both G1 and G2 were able to infect all four cell lines tested. The number of infected cells where at least one intracellular amastigote of T. copemani G1 and G2 was seen was below 7% and 15% respectively in most cell lines. However, in VERO cells the rate of infection for T. copemani G2 was 70%-approximately seven and two times higher than for G1 and T. cruzi respectively. Despite the higher infection rate, the number of intracellular forms of T. copemani G2 was lower compared with T. cruzi, and intracellular replicating forms were not observed. The capability of T. copemani G2 to infect cells may have important consequences for pathogenicity and suggests it might employ similar strategies to complete its life cycle in the vertebrate host to those seen in T. cruzi

Next generation sequencing reveals widespread trypanosome diversity and polyparasitism in marsupials from Western Australia

In Western Australia a number of indigenous Trypanosoma spp. infect susceptible native marsupials, such as the woylie (Bettongia penicillata), brushtail possum (Trichosurus vulpecula), and chuditch (Dasyurus geoffroii). Two genotypes of Trypanosoma copemani (identified as G1 and G2) have been found in the woylie, and G2 has been implicated in the decline of this host species, making its presence of particular interest. Here we used targeted amplicon next generation sequencing (NGS) of the Trypanosoma 18S rDNA loci on 70 Trypanosoma-positive marsupial blood samples, to identify T. copemani genotypes and multiple Trypanosoma infections (polyparasitism) in woylies and cohabiting species in Western Australia. Polyparasitism with Trypanosoma spp. was found in 50% of the wildlife sampled, and within species diversity was high, with 85 zero-radius operational taxonomic units (ZOTUs) identified in nine putative parasite species. Trypanosoma copemani was assigned 17 ZOTUs and was identified in 80% of samples. The most abundant ZOTU isolated (63%) differed slightly from the published genotype of G1, and G2 was the second most abundant ZOTU (14%). Trypanosome diversity was significantly greater in woylies than in brushtail possums, and parasite community composition also differed significantly between these host species. One novel Trypanosoma spp. genotype (Trypanosoma sp. ANU2) was found in 20% of samples. A species of Crithidia was detected in a woylie, and two avian trypanosomes (Trypanosoma avium and Trypanosoma sp. AAT) were identified in woylies for the first time

Breech Presentation: Vaginal Versus Cesarean Delivery, Which Intervention Leads to the Best Outcomes?

The best route of delivery for the term breech fetus is still controversial. We aim to compare maternal and neonatal outcomes between vaginal and cesarean term breech deliveries.info:eu-repo/semantics/publishedVersio

Threat-sensitive anti-predator defence in precocial wader, the northern lapwing Vanellus vanellus

Birds exhibit various forms of anti-predator behaviours to avoid reproductive failure, with mobbing—observation, approach and usually harassment of a predator—being one of the most commonly observed. Here, we investigate patterns of temporal variation in the mobbing response exhibited by a precocial species, the northern lapwing (Vanellus vanellus). We test whether brood age and self-reliance, or the perceived risk posed by various predators, affect mobbing response of lapwings. We quantified aggressive interactions between lapwings and their natural avian predators and used generalized additive models to test how timing and predator species identity are related to the mobbing response of lapwings. Lapwings diversified mobbing response within the breeding season and depending on predator species. Raven Corvus corax, hooded crow Corvus cornix and harriers evoked the strongest response, while common buzzard Buteo buteo, white stork Ciconia ciconia, black-headed gull Chroicocephalus ridibundus and rook Corvus frugilegus were less frequently attacked. Lapwings increased their mobbing response against raven, common buzzard, white stork and rook throughout the breeding season, while defence against hooded crow, harriers and black-headed gull did not exhibit clear temporal patterns. Mobbing behaviour of lapwings apparently constitutes a flexible anti-predator strategy. The anti-predator response depends on predator species, which may suggest that lapwings distinguish between predator types and match mobbing response to the perceived hazard at different stages of the breeding cycle. We conclude that a single species may exhibit various patterns of temporal variation in anti-predator defence, which may correspond with various hypotheses derived from parental investment theory

The ocean sampling day consortium

Ocean Sampling Day was initiated by the EU-funded Micro B3 (Marine Microbial Biodiversity, Bioinformatics, Biotechnology) project to obtain a snapshot of the marine microbial biodiversity and function of the world’s oceans. It is a simultaneous global mega-sequencing campaign aiming to generate the largest standardized microbial data set in a single day. This will be achievable only through the coordinated efforts of an Ocean Sampling Day Consortium, supportive partnerships and networks between sites. This commentary outlines the establishment, function and aims of the Consortium and describes our vision for a sustainable study of marine microbial communities and their embedded functional traits