The Effect of a Fast-Releasing Hydrogen Sulfide Donor on Vascularization of Subcutaneous Scaffolds in Immunocompetent and Immunocompromised Mice.

Islet transplantation into subcutaneous polymer scaffolds has shown to successfully induce normoglycemia in type 1 diabetes models. Vascularization of these scaffolds is imperative for optimal control of glucose levels. We studied the effect of the vascular stimulator hydrogen sulfide (H2S) on the degree of vascularization of a scaffold and the role of the immune system in this process. Scaffolds were subcutaneously implanted in immunocompetent C57BL/6 and immunocompromised nude mice. Mice received twice-daily intraperitoneal injections of the fast-releasing H2S donor sodium hydrosulfide (NaHS, 25 or 50 µmol/kg) or saline for 28 days. After 63 days the vascular network was analyzed by histology and gene expression. Here we showed that the vascularization of a subcutaneous scaffold in nude mice was significantly impaired by H2S treatment. Both the CD31 gene and protein expression were reduced in these scaffolds compared to the saline-treated controls. In C57BL/6 mice, the opposite was found, the vascularization of the scaffold was significantly increased by H2S. The mRNA expression of the angiogenesis marker CD105 was significantly increased compared to the controls as well as the number of CD31 positive blood vessels. In conclusion, the immune system plays an important role in the H2S mediated effect on vascularization of subcutaneous scaffolds.

Combined dietary supplementation of long chain inulin and Lactobacillus acidophilus W37 supports oral vaccination efficacy against Salmonella Typhimurium in piglets.

Routine use of antibiotics in livestock animals strongly contributed to the creation of multidrug-resistant Salmonella Typhimurium strains (STM). Vaccination is an alternative to the use of antibiotics but often suffers from low efficacy. The present study investigated whether long-chain inulin (lcITF) and Lactobacillus acidophilus W37 (LaW37) can support vaccination efficacy against STM and if the interventions influence possible gut microbiota changes. Piglets received daily supplementation until sacrifice. Animals were vaccinated on day 25 after birth, one day after weaning, and were challenged with STM on days 52-54. Dietary intervention with lcITF/LaW37 enhanced vaccination efficacy by 2-fold during challenge and resulted in higher relative abundance of Prevotellaceae and lower relative abundance of Lactobacillaceae in faeces. Although strongest microbial effects were observed post STM challenge on day 55, transient effects of the lcITF/LaW37 intervention were also detected on day 10 after birth, and post-weaning on day 30 where increased relative abundance of faecal lactobacilli was correlated with higher faecal consistency. LcITF treatment increased post-weaning feed efficiency and faecal consistency but did not support vaccination efficacy. Vaccination in immune-immature young animals can be enhanced with functional additives which can simultaneously promote health in an ingredient-dependent fashion.

Sphingobacterium cellulitidis sp. nov., isolated from clinical and environmental sources.

The taxonomic position of two isolates belonging to the genus Sphingobacterium was determined. The first isolate, R-53603T, was obtained from purulent discharge from the toe of a cellulitis patient in Kuwait. Comparative 16S rRNA gene sequence analysis revealed 99.87 % similarity of R-53603T with environmental isolate P031 (=R-53745) originating from activated sludge in Singapore. The two isolates were phylogenetically positioned on the same sub-branch. Highest 16S rRNA gene sequence similarity was found with the type strains of Sphingobacterium mizutaii (98.23 %), Sphingobacterium lactis (97.78 %) and Sphingobacterium daejeonense (97.14 %). DNA-DNA hybridizations revealed <70 % relatedness between the two isolates and the type strains of the close phylogenetic neighbours S. mizutaii(18.0-24.5 %), S. lactis(20.3-25.9 %) and S. daejeonense(13.2-20.0 %). The high relative contribution of iso-C15 : 0, iso-C17 : 0 3-OH and summed feature 3 (iso-C15 : 0 2-OH and/or C16 : 1ω7c) in the cellular fatty acid profiles of R-53603T and R-53745, the presence of sphingophospholipids, MK-7 as the dominant menaquinone and phosphatidylethanolamine as the major polar lipid in strain R-53603T are typical chemotaxonomic characteristics for members of the genus Sphingobacterium. Phenotypic features most useful for differentiation of the two novel strains from the most closely related species S. mizutaii include growth on MacConkey agar, and utilization of stachyose, guanidine HCl and lithium chloride in Biolog GEN III tests. Strains R-53603T and R-53745 thus represent a novel species, for which the name Sphingobacterium cellulitidis sp. nov. is proposed. The type strain is R-53603T (=LMG 28764T=DSM 102028T).

An MLSA-based online scheme for the rapid identification of Stenotrophomonas isolates

An online scheme to assign Stenotrophomonas isolates to genomic groups was developed using the multilocus sequence analysis (MLSA), which is based on the DNA sequencing of selected fragments of the housekeeping genes ATP synthase alpha subunit (atpA), the recombination repair protein (recA), the RNA polymerase alpha subunit (rpoA) and the excision repair beta subunit (uvrB). This MLSA-based scheme was validated using eight of the 10 Stenotrophomonas species that have been previously described. The environmental and nosocomial Stenotrophomonas strains were characterised using MLSA, 16S rRNA sequencing and DNA-DNA hybridisation (DDH) analyses. Strains of the same species were found to have greater than 95 percent concatenated sequence similarity and specific strains formed cohesive readily recognisable phylogenetic groups. Therefore, MLSA appeared to be an effective alternative methodology to amplified fragment length polymorphism fingerprint and DDH techniques. Strains of Stenotrophomonas can be readily assigned through the open database resource that was developed in the current study (www.steno.lncc.br/).

Monitoring poly(3-hydroxybutyrate) production in cupriavidus necator DSM 428 (H16) with raman spectroscopy.

This study explored the potential of Raman spectroscopy for the analysis of poly(3-hydroxybutyrate) (PHB) in bacteria. PHB can be formed in large amounts by certain bacteria as a storage material and is of high importance for industrial biodegradable plastic production. Raman spectra were collected from Cupriavidus necator DSM 428 (H16), from its non-PHB-producing mutant strain C. necator DSM 541, and from pure PHB, in order to determine at which Raman shifts a contribution of PHB in bacterial spectra can be expected. The Raman band intensity at ca. 1734 cm(-1) appeared to be suitable for the monitoring of PHB production and consumption. These intensities were linearly related to the PHB concentration (mg L(-1) culture) determined by parallel HPLC analysis. Therefore, Raman spectroscopy is considered as a fast and noninvasive technique for the determination and monitoring of the PHB content in bacteria.