Epidemiological characteristics of infections caused by Bacteroides, Prevotella and Fusobacterium species: a prospective observational study

In order to investigate differences among infections due to Gram-negative anaerobic bacteria (Bacteroides, Prevotella and Fusobacterium spp.), clinical, epidemiological, and microbiological data were collected and evaluated from 206 anaerobic infections. The most frequently isolated species was Bacteroides fragilis. The majority of the cases were intra-abdominal infections (49%) followed by skin and soft tissue infections (24.7%). Logistic regression analysis showed that Bacteroides spp. strains were more often isolated from intra-abdominal infections (p?=?0.002), whereas Prevotella spp. were isolated more frequently from cases with shorter duration of hospitalization (p?=?0.026), and less frequently from bloodstream infections (p?=?0.049). In addition, Bacteroides spp. were associated with coinfection due to Enterobacteriaceae species (p?=?0.007), whereas Prevotella spp. were associated with coinfection due to Staphylococcus spp. (p?=?0.002). Patients with an infection due to B.?fragilis, were more frequently admitted in a general surgical ward (p?=?0.017), or have been treated with a 2nd generation cephalosporin before anaerobic infection onset (p?=?0.05). Total mortality was 10.9% and was associated with bacteremia (p?=?0.026), and hematological (p?=?0.028), or solid organ malignancy (p?=?0.007). Metronidazole resistance was detected only among Prevotella spp. (16.2%) and B. fragilis group (0.8%) isolates. In conclusion, this study indicated differences between infections due to the most frequently isolated Gram-negative anaerobic species, differences that may affect the design and implementation of empirical antimicrobial chemotherapy guidelines.     

Complete genome sequence of the facultatively anaerobic, appendaged bacterium Muricauda ruestringensis type strain (B1(T))

Muricauda ruestringensis Bruns et al. 2001 is the type species of the genus Muricauda, which belongs to the family Flavobacteriaceae in the phylum Bacteroidetes. The species is of interest because of its isolated position in the genomically unexplored genus Muricauda, which is located in a part of the tree of life containing not many organisms with sequenced genomes. The genome, which consists of a circular chromosome of 3,842,422 bp length with a total of 3,478 protein-coding and 47 RNA genes, is a part of the Genomic Encyclopedia of Bacteria and Archaea project.     

A comparative chemotaxonomic study of eight taxa of the Dipsacaceae family

ABSTRACT

Eight taxa of the Dipsacaceae family were examined for their fatty acid and sterol composition. Separation and identification of the lipid fraction was achieved by gas chromatography and gas chromatography-mass spectrometry. The phenotypic differences among taxa were established by cluster analysis. Correlation coefficients were obtained to investigate numerical relationships among constituents of the fatty acids. The results showed many significant correlations between different constituents, as well as four clusters of taxa using two linkage types of clustering.     

Photomorphogenic reactions in geranium (Pelargonium x hortotum) plants stimulated by brief exposures of ultraviolet-C irradiation

Of all environmental factors that influence plant growth and development, light and other regions of the electromagnetic spectrum are most essential. In the present study, the effects of ultraviolet-C (UV-C) irradiation on two cultivars, Victor and Glacis, of pot grown geranium (Pelargonium x hortotum) plants were evaluated. Two-year experimental data showed that low doses of UV-C (i.e. 0.5–5.0?kJ?m^?2) irradiation led to photomorphogenic changes recorded as increases of fresh and dry weight, number of lateral stems and number of inflorescences formed. Although changes were recorded for both cultivars, responses to UV-C were population dependent with cv. Glacis appearing to be the more responsive one. The number of inflorescences formed on UV-C irradiated cv. Glacis plants was significantly (P?<?0.05) higher to that of the non-irradiated controls throughout the pot trials in 2010 and 2011. For example, in the 2010 pot trial, exposure to 2.5?kJ?m^?2 UV-C resulted in the increase of inflorescences by 75?%. Additionally, the number of lateral stems on UV-C irradiated plants of cvs. Victor and Glacis increased by 122?% and 64?%, respectively. Temperatures and PARs during the 2-year pot trials varied to a considerable level and seem to have affected floral development and growth of both cultivars. However, only in cv. Glacis the effect on floral development was significant as cv. Victor geraniums grown in 2010 and 2011 showed comparable numbers of inflorescences. Our results show that brief exposures of geranium plants to UV-C may facilitate the production of high quality final products in a cost effective and environmentally friendly way.     

Characterization of MCU-Binding Proteins MCUR1 and CCDC90B — Representatives of a Protein Family Conserved in Prokaryotes and Eukaryotic Organelles

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The use of stable isotope-labeled glycerol and oleic acid to differentiate the hepatic functions of DGAT1 and -2

Diacylglycerol acyltransferase (DGAT) catalyzes the final step in triglyceride (TG) synthesis. There are two isoforms, DGAT1 and DGAT2, with distinct protein sequences and potentially different physiological functions. To date, the ability to determine clear functional differences between DGAT1 and DGAT2, especially with respect to hepatic TG synthesis, has been elusive. To dissect the roles of these two key enzymes, we pretreated HepG2 hepatoma cells with (13)C(3)-D(5)-glycerol or (13)C(18)-oleic acid, and profiled the major isotope-labeled TG species by liquid chromatography tandem mass spectrometry. Selective DGAT1 and DGAT2 inhibitors demonstrated that (13)C(3)-D(5)-glycerol-incorporated TG synthesis was mediated by DGAT2, not DGAT1. Conversely, (13)C(18)-oleoyl-incorporated TG synthesis was predominantly mediated by DGAT1. To trace hepatic TG synthesis and VLDL triglyceride (VLDL-TG) secretion in vivo, we administered D(5)-glycerol to mice and measured plasma levels of D(5)-glycerol-incorporated TG. Treatment with an antisense oligonucleotide (ASO) to DGAT2 led to a significant reduction in D(5)-glycerol incorporation into VLDL-TG. In contrast, the DGAT2 ASO had no effect on the incorporation of exogenously administered (13)C(18)-oleic acid into VLDL-TG. Thus, our results indicate that DGAT1 and DGAT2 mediate distinct hepatic functions: DGAT2 is primarily responsible for incorporating endogenously synthesized FAs into TG, whereas DGAT1 plays a greater role in esterifying exogenous FAs to glycerol.     

Defective activation of ERK in macrophages lacking the p50/p105 subunit of NF-kappaB is responsible for elevated expression of IL-12 p40 observed after challenge with Helicobacter hepaticus

Helicobacter hepaticus is an enterohepatic Helicobacter species that induces lower bowel inflammation in susceptible mouse strains, including those lacking the p50/p105 subunit of NF-kappaB. H. hepaticus-induced colitis is associated with elevated levels of IL-12 p40 expression, and p50/p105-deficient macrophages express higher levels of IL-12 p40 than wild-type macrophages after challenge with H. hepaticus. However, the molecular mechanisms by which the p50/p105 subunit of NF-kappaB suppresses IL-12 p40 expression have not yet been elucidated. In this study we have demonstrated that H. hepaticus challenge of macrophages induces ERK activation, and this event plays a critical role in inhibiting the ability of H. hepaticus to induce IL-12 p40. Activation of ERK requires both p50/p105 and the MAPK kinase kinase, Tpl-2. Inhibition of the induction of IL-12 p40 by ERK was independent of c-Rel, a known positive regulator of IL-12 p40. Instead, it was linked to the induction of c-Fos, a known inhibitor of IL-12 p40 expression. These results suggest that H. hepaticus induces ERK activation by a pathway dependent upon Tpl-2 and p105, and that activation of ERK inhibits the expression of IL-12 p40 by inducing c-Fos. Thus, a defect in ERK activation could play a pivotal role in the superinduction of IL-12 p40 observed after challenge of macrophages lacking the p50/p105 subunit of NF-kappaB with H. hepaticus.     

Endosomal Fusion upon SNARE Knockdown is Maintained by Residual SNARE Activity and Enhanced Docking

SNARE proteins mediate membrane fusion in the secretory pathway of eukaryotic cells. Genetic deletion and siRNA-based knockdown have been instrumental in assigning given SNAREs to defined intracellular transport steps. However, SNARE depletion occasionally results in barely detectable phenotypes. To understand how cells cope with SNARE loss, we have knocked down several SNAREs functioning in early endosome fusion. Surprisingly, knockdown of syntaxin 13, syntaxin 6 and vti1a, alone or in combinations, did not result in measurable changes of endosomal trafficking or fusion. We found that the residual SNARE levels (typically ∼10%) were sufficient for a substantial amount of SNARE–SNARE interactions. Conversely, in wild-type cells, most SNARE molecules were concentrated in clusters, constituting a spare pool not readily available for interactions. Additionally, the knockdown organelles exhibited enhanced docking. We conclude that SNAREs are expressed at much higher levels than needed for maintenance of organelle fusion, and that loss of SNAREs is compensated for by the co-regulation of the docking machinery.