Selective Isolation of Bifidobacterium From Human Faeces Using Pangenomics, Metagenomics, and Enzymology

Bifidobacterium, an important genus for human health, is difficult to isolate. We applied metagenomics, pangenomics, and enzymology to determine the dominant glycoside hydrolase (GH) families of Bifidobacterium and designed selective medium for Bifidobacterium isolation. Pangenomics results showed that the GH13, GH3, GH42, and GH43 families were highly conserved in Bifidobacterium. Metagenomic analysis of GH families in human faecal samples was performed. The results indicated that Bifidobacterium contains core GHs for utilizing raffinose, D-trehalose anhydrous, D(+)-cellobiose, melibiose, lactulose, lactose, D(+)-sucrose, resistant starch, pullulan, xylan, and glucan. These carbohydrates as the main carbon sources were applied for selective media, which were more conducive to the growth of bifidobacteria. In the medium with lactose, raffinose and xylan as the main carbon sources, the ratio of cultivable bifidobacteria to cultivable microorganisms were 89.39% ± 2.50%, 71.45% ± 0.99%, and 53.95% ± 1.22%, respectively, whereas the ratio in the ordinary Gifu anaerobic medium was only 17.90% ± 0.58%. Furthermore, the species significantly (p < 0.05) varied among samples from different individuals. Results suggested that xylan might be a prebiotic that benefits host health, and it is feasible to screen and isolate bifidobacteria using the oligosaccharides corresponding to the specific GHs of bifidobacteria as the carbon sources of the selective media.

Pelvic Actinomycosis

Introduction. Actinomycosis is a chronic bacterial infection caused byActinomyces, Gram-positive anaerobic bacteria. Its symptomatology imitates some malignant pelvic tumours, tuberculosis, or nocardiosis, causing abscesses and fistulas. Actinomycoses are opportunistic infections and require normal mucous barriers to be altered. No epidemiological studies have been conducted to determine prevalence or incidence of such infections.Objective.To analyse the clinical cases of pelvic actinomycosis reported worldwide, to update the information about the disease.Methods.A systematic review of worldwide pelvic actinomycosis cases between 1980 and 2014 was performed, utilising the PubMed, Scopus, and Google Scholar databases. The following information was analysed: year, country, type of study, number of cases, use of intrauterine device (IUD), final and initial diagnosis, and method of diagnosis.Results.63 articles met the search criteria, of which 55 reported clinical cases and 8 reported cross-sectional studies.Conclusions.Pelvic actinomycosis is confusing to diagnose and should be considered in the differential diagnosis of pelvic chronic inflammatory lesions. It is commonly diagnosed through a histological report, obtained after a surgery subsequent to an erroneous initial diagnosis. A bacterial culture in anaerobic medium could be useful for the diagnosis but requires a controlled technique and should be performed using specialised equipment.

Bamboo as an anaerobic medium: effect of filter column height

Sewage was treated in anaerobic filters filled with rings of bamboo (either whole or cut), and their effectiveness in the reduction of chemical oxygen demand (COD) was monitored along the entire extension of the filter. This efficiency was determined based on the COD reduction in both the brute effluent (COD-T) and that passed through a glass filter (COD-F). The quantity of total suspended solids (TSS) present at various heights in the filter column, measured at approximately 10-cm intervals from the false bottom to the height of the filter outflow (80 cm above) for various hydraulic detention times (HDT). The performance of the system resulted in little variation up to 5 hours of HDT, with the percentage of reduction of COD-T and COD-F being situated in the range of 60-80% and 40-80%, respectively. The first 40 cm of the filter proved to be relatively effective, and no significant differences in performance between whole and cut rings of bamboo were observed. A shock in pH occurring after 562 days of operation provoked an immediate and marked decrease in the performance of the reactors, especially that operating with a HDT of only 2 hours. This latter filter required more time to return to normal operational conditions than did the other reactors operating with longer HDT.

Investigation of direct gas production from silage fermentation acids

During ensilage readily fermentable organic matter (OM) is fermented to lactic acid and short chain volatile fatty acids (VFA). These acids provide little energy as ATP for rumen microbial growth and are essentially absorbed intact. The UK metabolisable protein system defined the energy available for microbial growth, termed fermentable metabolisable energy (FME), as the proportion of metabolisable energy (ME) in a diet/feed less the ME in oil and fermentation acids. The aim was to establish if fermentation acids yield direct gas production resulting from microbial fermentation. Grass silage was simulated using grass hay (GH; containing no fermentation acids) with additions of individual fermentation acids in solution.GH (~2 kg) was oven-dried overnight at 100°C, nulled (1 mm screen) and then sieved (25 μm screen). 0.5 g GH was weighed into 250 ml Duran bottles according to the treatments; 1) GH + anaerobic incubation mixture (AIM, 85/15 v/v anaerobic medium and strained rumen fluid) + ~5 ml distilled water; 2) GH + AIM + ~5 ml fermentation acid solution (100 mg DL-lactic acid (LA)/10 ml, 30 mg acetic acid (AA)/10 ml or 20 mg n-butyric acid (BA)/10 ml) (equivalent to 100, 30 and 20 mg/g GH dry matter (DM) for LA, AA and BA respectively); 3) anaerobic medium (85 ml) + 15 ml clarified rumen fluid + ~5 ml fermentation acid (as treatment (2)).

Investigation of direct gas production from silage fermentation acids

During ensilage readily fermentable organic matter (OM) is fermented to lactic acid and short chain volatile fatty acids (VFA). These acids provide little energy as ATP for rumen microbial growth and are essentially absorbed intact. The UK metabolisable protein system defined the energy available for microbial growth, termed fermentable metabolisable energy (FME), as the proportion of metabolisable energy (ME) in a diet/feed less the ME in oil and fermentation acids. The aim was to establish if fermentation acids yield direct gas production resulting from microbial fermentation. Grass silage was simulated using grass hay (GH; containing no fermentation acids) with additions of individual fermentation acids in solution.GH (~2 kg) was oven-dried overnight at 100°C, nulled (1 mm screen) and then sieved (25 μm screen). 0.5 g GH was weighed into 250 ml Duran bottles according to the treatments; 1) GH + anaerobic incubation mixture (AIM, 85/15 v/v anaerobic medium and strained rumen fluid) + ~5 ml distilled water; 2) GH + AIM + ~5 ml fermentation acid solution (100 mg DL-lactic acid (LA)/10 ml, 30 mg acetic acid (AA)/10 ml or 20 mg n-butyric acid (BA)/10 ml) (equivalent to 100, 30 and 20 mg/g GH dry matter (DM) for LA, AA and BA respectively); 3) anaerobic medium (85 ml) + 15 ml clarified rumen fluid + ~5 ml fermentation acid (as treatment (2)).

Membrane association and isolation of the S-layer protein of Methanoculleus marisnigri

Methanoculleus marisnigri is an irregularly shaped coccoid member of the methanogenic archaeobacteria. The cells possessed a hexagonally arranged, glycosylated S-layer as the sole wall component. The lattice spacing was approximately 13.5 nm. Plasmolysis in anaerobic medium with 20% sucrose did not separate the plasma membrane from the S-layer. The S-layer–membrane complex formed a tight but noncovalent association, was deformable, and was not a rigid structure. The 138-kDa glycoprotein was not solubilized by guanidine hydrochloride or urea, but it was solubilized in the detergent Triton X-100 at temperatures above 60 °C, and purified by phase separation at 75 °C of the detergent-soluble extract. The amino acid composition of the glycoprotein was similar to that reported for other S-layer proteins.Key words: methanogen, archaeobacteria (archaea), S-layer, glycoprotein, Triton X-100.