Characterization and biological activities of a novel exopolysaccharide produced from Geobacillus thermodenitrificans HBB 111 strain.

In this study, EPS production conditions of Geobacillus thermodenitrificans HBB 111, a thermophilic microorganism, were optimized and the amount of produced EPS (EPS 111) was found to be 44.0 mg/L. EPS 111 was purified using ion exchange chromatography and gel filtration chromatography, and a single type of exopolysaccharide was obtained. The structure of the purified EPS 111 was evaluated by TLC, FTIR, NMR, and GC-MS, and it was observed that it contained hexose (glucose, fructose, galactose and mannose) and pentose sugars. From the SEM photographs, it was understood that EPS 111 had an amorphous, rough, and layered structure. It was found that purified EPS 111 had low cytotoxicity (2.3%) and exhibited high antioxidant activity and remarkable antidiabetic, prebiotic and fibrinolytic activities. It is very valuable that the purified EPS 111 in this study offers multiple biological activities compared to the thermophilic EPSs reported in the literature and has a high potential for use in biotechnological and biomedical fields.

Metagenomic analysis of wastewater phageome from a University Hospital in Turkey.

Phage DNA analysis gives opportunity to understand living ecosystem of the environment where the samples are taken. In the present study, we analyzed phage DNA obtained from wastewater sample of university hospital sewage. After filtration, long high-speed centrifugation was done to collect phages. DNA was extracted from pellet by phenol chloroform extraction and used for NGS sequencing. The host profile, taxonomic and functional analyses were performed using MG-RAST, and ResFinder program was used for resistance gene detection. High amounts of reads belong to bacteriophage groups (~ 95%) from our DNA sample were obtained and all bacteriophage reads were found belonging to Caudovirales order and Myoviridae (56%), Siphoviridae (43%), and Podoviridae (0.02%) families. The most common host genera were Escherichia (88.20%), Salmonella (5.49%) and Staphylococcus (5.19%). SEED subsystems hits were mostly structural parts and KEGG Orthology hits were nucleotide- and carbohydrate metabolism-related genes. No anti-microbial resistance genes were detected. Our bacteriophage DNA purification method is favorable for phage metagenomic studies. Dominance of coliphages may explain infrequent Podoviridae. Dominancy of structural genes and auxiliary genes is probably due to abundance of lytic phages in our sample. Absence of antibiotic resistance genes even in hospital environment phages indicates that phages are not important carrier of resistance genes.

Bacteria killer enzyme attached magnetic nanoparticles.

The objective of the present work was to develop immobilized lysozyme systems through adsorption on magnetic nanoparticles for potential usage in bacteria killing studies. For this, magnetic poly(HEMA-GMA) nanoparticles were prepared by surfactant free emulsion polymerization technique and functionalized with dye ligand Reactive Green 5. Synthesized magnetic nanoparticles were then characterized by FTIR, SEM, EDX and ESR studies. Particle size range of the polymers was found to be as 90-120 nm. Magnetic behavior was also demonstrated by ESR with the g value of 2.48. Maximum lysozyme loading was found to be as 1045.1 mg/g nanopolymer. Repeated usability of the magnetic nanoparticles was also studied. Immobilized form of lysozyme protected 85.85% of its initial activity at the end of the immobilization process. Bacteria killing capacity of the lysozyme immobilized magnetic nanoparticles were investigated by using Micrococcus lysodeikticus bacteria and it was demonstrated that all bacteria were successfully destroyed by the lysozyme immobilized magnetic nanoparticles within 5 min.

Biological decolorization of textile dyes from isolated microfungi.

In this study, biological decolorization of two textile dyestuff (Benazol black ZN and Cibacron black W-NN) was comparatively studied using 22 microfungi strains isolated from polluted industrial soil areas. The initial dye concentrations in the medium were 250 and 500 mg l(-1). Benazol black ZN was the best decolorized by Haematonectria haematococca (HH1) (36.0%) and Cibacron black W-NN was the best decolorized by Aspergillus niger (AN1) (33.0%) at 250 mg l(-1) dye concentration. At 500 mg l(-1) dye concentration for two different dyes all microfungi strains used showed weak decolorization rates, maximum 13.0% for Benazol black ZN and 6.0% for Cibacron Black W-NN.

The short-term effects of different doses of dexamethasone on the numbers of some bacteria in the ileum.

Glucocorticoids are known to affect intestinal biota both directly or indirectly. The aim of the study reported here was to determine the short-term effects of different doses of dexamethasone on the numbers of various ileal bacteria populations. Rats were randomly put into groups, and each group was administered a single-dose injection of dexamethasone at either 0.1, 0.5, 1, 2.5, 5, or 10 mg/kg body weight. At 48-h post-injection, the numbers of total aerobe, anaerobe, lactobacilli and coliform bacteria in the ileum were determined. The numbers of total aerobes and lactobacilli were higher in the groups receiving 5 and 10 mg/kg dexamethasone than in the control and other dose groups (P < 0.01 and P < 0.001, respectively). The number of ileal anaerobic bacteria was higher in group receiving 5 mg/kg than in the other groups (P < 0.01). There were more coliform bacteria in the group receiving 0.1 mg/kg than in the groups receiving 0.5, 1 and 10 mg/kg (P < 0.05). In light of these results, the effects of dose-dependent increases in the number of different bacterial groups affecting gut functions have still to be determined in future studies.

Characterization of esterase activity in Geobacillus sp. HBB-4.

A thermophilic esterase producing bacterium (Bacillus sp. 4), recently isolated from Alangüllü thermal spring in Aydin (Turkey), was analyzed using 16S rRNA and classified as Geobacillus sp. HBB-4, most closely related to Bacillus sp. BGSC W9A59 (0.70% sequence divergence) which belongs to the newly described genus Geobacillus. The effects of several chemicals on the activity of thermostable esterase from Geobacillus sp. HBB-4 were examined. Among the various metal ions tested, esterase activity was enhanced by Mn(+2) and Ni(+2), but was inhibited by Hg(+2) and Cu(+2), whereas Ca(+2), Mg(+2) and Co(+2) had no effect. In addition, other metal ions studied have caused a slight inhibition on the esterase activity. EDTA partially inhibited the HBB-4 esterase. The activator metal ions, Mn(+2) and Ni(+2) have restored partial inhibition of EDTA. The activity of HBB-4 esterase was inhibited by ionic detergents while non-ionic detergents activated the enzyme. However, a zwitterionic detergent, CHAPS, has caused a slight inhibition in the enzyme activity. HBB-4 esterase activity was inhibited at the high concentrations of all the organic solvents tested in the present study. However, 50% final concentration of DMSO increased the enzyme activity about 7%. The HBB-4 esterase has shown more than about 50% of activity in the presence of ethanol and methanol solutions. These characteristics of the enzyme along with its significant thermostability make the Geobacillus sp. HBB-4 esterase a potent candidate for future industrial applications.