Phylogenetic and Functional Diversity Within Toluene-Degrading,Sulphate-Reducing Consortia Enriched from a Contaminated Aquifer

Three toluene-degrading microbial consortia were enriched under sulphate-reducing conditions from different zones of a benzene, toluene, ethylbenzene and xylenes (BTEX) plume of two connected contaminated aquifers. Two cultures were obtained from a weakly contaminated zone of the lower aquifer, while one culture originated from the highly contaminated upper aquifer. We hypothesised that the different habitat characteristics are reflected by distinct degrader populations. Degradation of toluene with concomitant production of sulphide was demonstrated in laboratory microcosms and the enrichment cultures were phylogenetically characterised. The benzylsuccinate synthase alpha-subunit (bssA) marker gene, encoding the enzyme initiating anaerobic toluene degradation, was targeted to characterise the catabolic diversity within the enrichment cultures. It was shown that the hydrogeochemical parameters in the different zones of the plume determined the microbial composition of the enrichment cultures. Both enrichment cultures from the weakly contaminated zone were of a very similar composition, dominated by Deltaproteobacteria with the Desulfobulbaceae (a Desulfopila-related phylotype) as key players. Two different bssA sequence types were found, which were both affiliated to genes from sulphate-reducing Deltaproteobacteria. In contrast, the enrichment culture from the highly contaminated zone was dominated by Clostridia with a Desulfosporosinus-related phylotype as presumed key player. A distinct bssA sequence type with high similarity to other recently detected sequences from clostridial toluene degraders was dominant in this culture. This work contributes to our understanding of the niche partitioning between degrader populations in distinct compartments of BTEX-contaminated aquifers.     

Diverse Virulence Gene Content of Shiga Toxin-Producing Escherichia coli from Finishing Swine

Shiga toxin-producing Escherichia coli (STEC) infections are a critical public health concern because they can cause severe clinical outcomes, such as hemolytic uremic syndrome, in humans. Determining the presence or absence of virulence genes is essential in assessing the potential pathogenicity of STEC strains. Currently, there is limited information about the virulence genes carried by swine STEC strains; therefore, this study was conducted to examine the presence and absence of 69 virulence genes in STEC strains recovered previously from finishing swine in a longitudinal study. A subset of STEC strains was analyzed by pulsed-field gel electrophoresis (PFGE) to examine their genetic relatedness. Swine STEC strains (n = 150) were analyzed by the use of a high-throughput real-time PCR array system, which included 69 virulence gene targets. Three major pathotypes consisted of 16 different combinations of virulence gene profiles, and serotypes were determined in the swine STEC strains. The majority of the swine STEC strains (n = 120) belonged to serotype O59:H21 and carried the same virulence gene profile, which consisted of 9 virulence genes: stx_2e, iha, ecs1763, lpfA_O113, estIa (STa), ehaA, paa, terE, and ureD. The eae, nleF, and nleH1-2 genes were detected in one swine STEC strain (O49:H21). Other genes encoding adhesins, including iha, were identified (n = 149). The PFGE results demonstrated that swine STEC strains from pigs raised in the same finishing barn were closely related. Our results revealed diverse virulence gene contents among the members of the swine STEC population and enhance understanding of the dynamics of transmission of STEC strains among pigs housed in the same barn.     

A Mutation in VPS35, Encoding a Subunit of the Retromer Complex, Causes Late-Onset Parkinson Disease

To identify rare causal variants in late-onset Parkinson disease (PD), we investigated an Austrian family with 16 affected individuals by exome sequencing. We found a missense mutation, c.1858G>A (p.Asp620Asn), in the VPS35 gene in all seven affected family members who are alive. By screening additional PD cases, we saw the same variant cosegregating with the disease in an autosomal-dominant mode with high but incomplete penetrance in two further families with five and ten affected members, respectively. The mean age of onset in the affected individuals was 53 years. Genotyping showed that the shared haplotype extends across 65 kilobases around VPS35. Screening the entire VPS35 coding sequence in an additional 860 cases and 1014 controls revealed six further nonsynonymous missense variants. Three were only present in cases, two were only present in controls, and one was present in cases and controls. The familial mutation p.Asp620Asn and a further variant, c.1570C>T (p.Arg524Trp), detected in a sporadic PD case were predicted to be damaging by sequence-based and molecular-dynamics analyses. VPS35 is a component of the retromer complex and mediates retrograde transport between endosomes and the trans-Golgi network, and it has recently been found to be involved in Alzheimer disease.     

Interbacterial macromolecular transfer by the Campylobacter fetus subsp. venerealis type IV secretion system

We report here the first demonstration of intra- and interspecies conjugative plasmid DNA transfer for Campylobacter fetus. Gene regions carried by a Campylobacter coli plasmid were identified that are sufficient for conjugative mobilization to Escherichia coli and C. fetus recipients. A broader functional range is predicted. Efficient DNA transfer involves the virB9 and virD4 genes of the type IV bacterial secretion system encoded by a pathogenicity island of C. fetus subsp. venerealis. Complementation of these phenotypes from expression constructions based on the promoter of the C. fetus surface antigen protein (sap) locus was temperature dependent, and a temperature regulation of the sap promoter was subsequently confirmed under laboratory conditions. Gene transfer was sensitive to surface or entry exclusion functions in potential recipient cells carrying IncPα plasmid RP4 implying functional relatedness to C. fetus proteins. The virB/virD4 locus is also known to be involved in bacterial invasion and killing of cultured human cells in vitro. Whether specifically secreted effector proteins contribute to host colonization and infection activities is currently unknown. Two putative effector proteins carrying an FIC domain conserved in a few bacterial type III and type IV secreted proteins of pathogens were analyzed for secretion by the C. fetus or heterologous conjugative systems. No evidence for interbacterial translocation of the Fic proteins was found.     

Pivotal role for alpha1-antichymotrypsin in skin repair

α1-Antichymotrypsin (α1-ACT) is a specific inhibitor of leukocyte-derived chymotrypsin-like proteases with largely unknown functions in tissue repair. By examining human and murine skin wounds, we showed that following mechanical injury the physiological repair response is associated with an acute phase response of α1-ACT and the mouse homologue Spi-2, respectively. In both species, attenuated α1-ACT/Spi-2 activity and gene expression at the local wound site was associated with severe wound healing defects. Topical application of recombinant α1-ACT to wounds of diabetic mice rescued the impaired healing phenotype. LC-MS analysis of α1-ACT cleavage fragments identified a novel cleavage site within the reactive center loop and showed that neutrophil elastase was the predominant protease involved in unusual α1-ACT cleavage and inactivation in nonhealing human wounds. These results reveal critical functions for locally acting α1-ACT in the acute phase response following skin injury, provide mechanistic insight into its function during the repair response, and raise novel perspectives for its potential therapeutic value in inflammation-mediated tissue damage.     

Quallen an Nord‐ und Ostseeküste

Jellyfishes in the North and the Baltic Sea Jellyfish masses are not only a nuisance for bathers but have significant negative effects on marine ecosystems and economy. The causes of worldwide increasing jellyfish mass occurrences are not fully understood until today. Anthropogenic influences as submarine constructions, overfishing, eutrophication and climate warming are assumed as possible causes. Jellyfish and their relatives have fascinating capabilities and features, including their amazing regeneration potential, a high adaptability on changing environments and especially their weapons, the stinging capsules. Despite the simplicity of their nervous system jellyfish have astonishing perception senses.     

A new species and new records of Cercophora from Argentina

Three species of Cercophora were found during a survey of the biodiversity of microfungi in northwest Argentina. Cercophora argentina possesses a unique combination of morphological characters and is described as a new species, while C. costaricensis and C. solaris are reported as new records for Argentina. Other species of Cercophora known from this region include C. natalita and C. coprogena, which is fully illustrated for the first time and determined herein to be a synonym of C. californica. All other species are described and illustrated.     

Phylogeny, topology, structure and functions of membrane-bound class III peroxidases in vascular plants

Peroxidases are key player in the detoxification of reactive oxygen species during cellular metabolism and oxidative stress. Membrane-bound isoenzymes have been described for peroxidase superfamilies in plants and animals. Recent studies demonstrated a location of peroxidases of the secretory pathway (class III peroxidases) at the tonoplast and the plasma membrane. Proteomic approaches using highly enriched plasma membrane preparations suggest organisation of these peroxidases in microdomains, a developmentally regulation and an induction of isoenzymes by oxidative stress. Phylogenetic relations, topology, putative structures, and physiological function of membrane-bound class III peroxidases will be discussed.     

Genetic diversity, structure, gene flow and evolutionary relationships within the Sorghum bicolor wild�Cweedy�Ccrop complex in a western African region

Gene flow between domesticated plants and their wild relatives is one of the major evolutionary processes acting to shape their structure of genetic diversity. Earlier literature, in the 1970s, reported on the interfertility and the sympatry of wild, weedy and cultivated sorghum belonging to the species Sorghum bicolor in most regions of sub-Saharan Africa. However, only a few recent surveys have addressed the geographical and ecological distribution of sorghum wild relatives and their genetic structure. These features are poorly documented, especially in western Africa, a centre of diversity for this crop. We report here on an exhaustive in situ collection of wild, weedy and cultivated sorghum assembled in Mali and in Guinea. The extent and pattern of genetic diversity were assessed with 15 SSRs within the cultivated pool (455 accessions), the wild pool (91 wild and weedy forms) and between them. F (ST) and R (ST) statistics, distance-based trees, Bayesian clustering methods, as well as isolation by distance models, were used to infer evolutionary relationships within the wild-weedy-crop complex. Firstly, our analyses highlighted a strong racial structure of genetic diversity within cultivated sorghum (F (ST) = 0.40). Secondly, clustering analyses highlighted the introgressed nature of most of the wild and weedy sorghum and grouped them into two eco-geographical groups. Such closeness between wild and crop sorghum could be the result of both sorghum's domestication history and preferential post-domestication crop-to-wild gene flow enhanced by farmers' practices. Finally, isolation by distance analyses showed strong spatial genetic structure within each pool, due to spatially limited dispersal, and suggested consequent gene flow between the wild and the crop pools, also supported by R (ST) analyses. Our findings thus revealed important features for the collection, conservation and biosafety of domesticated and wild sorghum in their centre of diversity.