Search results for "Acte"

Repair of a Bacterial Small β-Barrel Toxin Pore Depends on Channel Width

2017

ABSTRACT Membrane repair emerges as an innate defense protecting target cells against bacterial pore-forming toxins. Here, we report the first paradigm of Ca2+-dependent repair following attack by a small β-pore-forming toxin, namely, plasmid-encoded phobalysin of Photobacterium damselae subsp. damselae. In striking contrast, Vibrio cholerae cytolysin, the closest ortholog of phobalysin, subverted repair. Mutational analysis uncovered a role of channel width in toxicity and repair. Thus, the replacement of serine at phobalysin´s presumed channel narrow point with the bulkier tryptophan, the corresponding residue in Vibrio cholerae cytolysin (W318), modulated Ca2+ influx, lysosomal exocytosi…

2017

The consequences of emerging marine diseases on the evolutionary trajectories of affected host populations in the marine realm are largely unexplored. Evolution in response to natural selection depends on the genetic variation of the traits under selection and the interaction of these traits with the environment (GxE). However, in the case of diseases, genotypes of pathogens add another dimension to this interaction. Therefore, the study of disease resistance needs to be extended to the interaction of host genotype, pathogen genotype and environment (GxGxE). In the present study we used a full-sib breeding design crossing two genetically differentiated populations of the Pacific oyster Cras…

The genetic prehistory of the Baltic Sea region

2018

Correction: Nature communications 9 (2018), art. no. 1494 doi:10.1038/s41467-018-03872-y While the series of events that shaped the transition between foraging societies and food producers are well described for Central and Southern Europe, genetic evidence from Northern Europe surrounding the Baltic Sea is still sparse. Here, we report genome-wide DNA data from 38 ancient North Europeans ranging from similar to 9500 to 2200 years before present. Our analysis provides genetic evidence that hunter-gatherers settled Scandinavia via two routes. We reveal that the first Scandinavian farmers derive their ancestry from Anatolia 1000 years earlier than previously demonstrated. The range of Mesolit…

Enhancing methane production from lignocellulosic biomass by combined steam-explosion pretreatment and bioaugmentation with cellulolytic bacterium Ca…

2018

Abstract Background Biogas production from lignocellulosic biomass is generally considered to be challenging due to the recalcitrant nature of this biomass. In this study, the recalcitrance of birch was reduced by applying steam-explosion (SE) pretreatment (210 °C and 10 min). Moreover, bioaugmentation with the cellulolytic bacterium Caldicellulosiruptor bescii was applied to possibly enhance the methane production from steam-exploded birch in an anaerobic digestion (AD) process under thermophilic conditions (62 °C). Results Overall, the combined SE and bioaugmentation enhanced the methane yield up to 140% compared to untreated birch, while SE alone contributed to the major share of methane…

Ochrobactrum sp. MPV1 from a dump of roasted pyrites can be exploited as bacterial catalyst for the biogenesis of selenium and tellurium nanoparticles

2017

Bacteria have developed different mechanisms for the transformation of metalloid oxyanions to non-toxic chemical forms. A number of bacterial isolates so far obtained in axenic culture has shown the ability to bioreduce selenite and tellurite to the elemental state in different conditions along with the formation of nanoparticles—both inside and outside the cells—characterized by a variety of morphological features. This reductive process can be considered of major importance for two reasons: firstly, toxic and soluble (i.e. bioavailable) compounds such as selenite and tellurite are converted to a less toxic chemical forms (i.e. zero valent state); secondly, chalcogen nanoparticles have att…

Biosynthesis of selenium-nanoparticles and -nanorods as a product of selenite bioconversion by the aerobic bacterium Rhodococcus aetherivorans BCP1

2018

The wide anthropogenic use of selenium compounds represents the major source of selenium pollution world- wide, causing environmental issues and health concerns. Microbe-based strategies for metal removal/recovery have received increasing interest thanks to the association of the microbial ability to detoxify toxic metal/ metalloid polluted environments with the production of nanomaterials. This study investigates the tolerance and the bioconversion of selenite (SeO32−) by the aerobically grown Actinomycete Rhodococcus aetherivorans BCP1 in association with its ability to produce selenium nanoparticles and nanorods (SeNPs and SeNRs). The BCP1 strain showed high tolerance towards SeO32− with…

Genomic characterization of Defluviitoga tunisiensis L3, a key hydrolytic bacterium in a thermophilic biogas plant and its abundance as determined by…

2016

The genome sequence of Defluviitoga tunisiensis L3 originating from a thermophilic biogas-production plant was established and recently published as Genome Announcement by our group. The circular chromosome of D. tunisiensis L3 has a size of 2,053,097bp and a mean GC content of 31.38%. To analyze the D. tunisiensis L3 genome sequence in more detail, a phylogenetic analysis of completely sequenced Thermotogae strains based on shared core genes was performed. It appeared that Petrotoga mobilis DSM 10674(T), originally isolated from a North Sea oil-production well, is the closest relative of D. tunisiensis L3. Comparative genome analyses of P. mobilis DSM 10674(T) and D. tunisiensis L3 showed …

NaCl-saturated brines are thermodynamically moderate, rather than extreme, microbial habitats

2018

NaCl-saturated brines such as saltern crystalliser ponds, inland salt lakes, deep-sea brines and liquids-of-deliquescence on halite are commonly regarded as a paradigm for the limit of life on Earth. There are, however, other habitats that are thermodynamically more extreme. Typically, NaCl-saturated environments contain all domains of life and perform complete biogeochemical cycling. Despite their reduced water activity, ∼0.755 at 5 M NaCl, some halophiles belonging to the Archaea and Bacteria exhibit optimum growth/metabolism in these brines. Furthermore, the recognised water-activity limit for microbial function, ∼0.585 for some strains of fungi, lies far below 0.755. Other biophysical c…

Gut Microbiota Condition the Therapeutic Efficacy of Trastuzumab in HER2-Positive Breast Cancer.

2021

Abstract Emerging evidence indicates that gut microbiota affect the response to anticancer therapies by modulating the host immune system. In this study, we investigated the impact of gut microbiota on immune-mediated trastuzumab antitumor efficacy in preclinical models of HER2-positive breast cancer and in 24 patients with primary HER2-positive breast cancer undergoing trastuzumab-containing neoadjuvant treatment. In mice, the antitumor activity of trastuzumab was impaired by antibiotic administration or fecal microbiota transplantation from antibiotic-treated donors. Modulation of the intestinal microbiota was reflected in tumors by impaired recruitment of CD4+ T cells and granzyme B–posi…

Prediabetes is associated with the modulation of antigen-specific Th1/Tc1 and Th17/Tc17 responses in latent Mycobacterium tuberculosis infection.

2017

Type 2 diabetes mellitus (DM) is associated with the down modulation of Th1, Th2 and Th17 responses in latent Mycobacterium tuberculosis infection but the role of prediabetes (PDM) in this setting is not well understood. To examine the role of CD4+ and CD8+ T cell cytokines in latent tuberculosis (LTB) with coincident PDM, we studied the baseline, mycobacterial, control antigen and mitogen-stimulated T cell cytokine responses in LTB individuals with (LTB-PDM; n = 20) or without (LTB-NDM; n = 20) concomitant prediabetes. LTB-PDM is characterized by diminished frequencies of mono-and dual-functional CD4+ Th1 and Th17 cells and mono-functional Th2 cells at baseline and/or following mycobacteri…