Isolation and identification of Legionella spp. from hot spring water in Algeria by culture and molecular methods

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Effect of Dietary n-3 Polyunsaturated Fatty Acids on Oxidant/Antioxidant Status in Macrosomic Offspring of Diabetic Rats

The aim of this work was to determine the effect of dietary n-3 PUFA on oxidant/antioxidant status, in vitro very low and low density lipoprotein (VLDL-LDL), and VLDL-LDL-fatty acid composition in macrosomic pups of diabetic mothers. We hypothesized that n-3 PUFA would improve oxidative stress in macrosomia. Diabetes was induced in female Wistar rats fed with the ISIO diet (control) or with the EPAX diet (enriched in n-3 PUFAs), by streptozotocin. The macrosomic pups were killed at birth (day 0) and at adulthood (day 90). Lipid parameters and VLDL-LDL-fatty acid composition were investigated. The oxidant/antioxidant status was determined by measuring plasma oxygen radical absorbance capacity (ORAC), hydroperoxides, carbonyl proteins, and VLDL-LDL oxidation. Macrosomic rats of ISIO fed diabetic mothers showed an increase in plasma and VLDL-LDL-triglycerides and VLDL-LDL-cholesterol levels and altered VLDL-LDL-fatty acid composition. Plasma ORAC was low with high hydroperoxide and carbonyl protein levels. The in vitro oxidizability of VLDL-LDL was enhanced in these macrosomic rats. The EPAX diet corrected lipid parameters and improved oxidant/antioxidant status but increased VLDL-LDL susceptibility to oxidation. Macrosomia is associated with lipid abnormalities and oxidative stress. n-3 PUFA exerts favorable effects on lipid metabolism and on the oxidant/antioxidant status of macrosomic rats. However, there are no evident effects on VLDL-LDL oxidation

Chryseobacterium solincola sp nov., isolated from soil

A Gram-staining-negative, yellow-pigmented, strictly aerobic bacterium, designated strain 1YB-R12(T), was isolated from a soil sample in western Algeria. The novel isolate was heterotrophic, chemoorganotrophic, halotolerant and psychrotolerant. The temperature and pH optima for growth were 28-30 degrees C and pH 7.3-8. The bacterium tolerated up to 6% (w/v) NaCl. Cells were non-motile, non-gliding and non-spore-forming, and were characterized by a variable morphological cycle. Flexirubin-type pigments were not detected. 16S rRNA gene sequence analysis showed that strain 1YB-R12(T) occupied a distinct lineage within the genus Chryseobacterium and shared highest sequence similarity with Chryseobacterium haifense LMG 24029(T) (96.5%). The DNA G+C content of strain 1YB-R12(T) was 40.9 mol%. The predominant cellular fatty acids were anteiso-C-15:0 (41.4%) and iso-C-15:0 (14.4%). On the basis of phenotypic properties and phylogenetic distinctiveness, strain 1YB-R12(T) is considered to represent a novel species of the genus Chryseobacterium, for which the name Chryseobacterium solincola sp. nov. is proposed. The type strain is 1YB-R12(T) (=DSM 22468(T)=CCUG 55604(T))

Isolation and characterization of halophilic archaea able to produce biosurfactants

Halotolerants microorganisms able to live in saline environments, offer a multitude of actual or potential applications in various fields of biotechnology. This is why some strains of Halobacteria from an Algerian culture collection were screened for biosurfactant production in a standard medium using the qualitative drop-collapse test and emulsification activity assay. Five of the Halobacteria strains reduced the growth medium surface tension below 40mNm-1 and two of them exhibited high emulsion-stabilising capacity. Diesel oil-in-water emulsions were stabilized over a broad range of conditions, from pH 2 to 11, with up to 35% sodium chloride or up to 25% ethanol in the aqueous phase. Emulsions were stable to three cycles of freezing and thawing. The components of the biosurfactant were determined; it contains sugar, protein and lipid. The two Halobacteria strains with enhanced biosurfactants producers designed strain A21 and strain D21 were selected to identify by phenotypic, biochemical characteristics and by partial 16S rRNA gene sequencing. The strains have Mg2+and salt growth requirements are always above 15% (w/v) salts with an optimal concentration of 15% to 20%. Analyses of partial 16S rRNA gene sequences of the two strains suggested that they were halophiles belonging to genera of the family Halobacteriaceae, Halovivax (strain A21) and Haloarcula (strain D21). To our knowledge, this a first report of biosurfactant production at such a high salt concentratio

Novel serine keratinase from Caldicoprobacter algeriensis exhibiting outstanding hide dehairing abilities

The current paper reports on the purification of an extracellular thermostable keratinase (KERCA) produced from Caldicoprobacter algeriensis strain TH7C1(T), a thermophilic, anaerobic bacterium isolated from a hydrothermal hot spring in Algeria. The maximum keratinase activity recorded after 24-h of incubation at 50 degrees C was 21000 U/ml. The enzyme was purified by ammonium sulfate precipitation-dialysis and heat treatment (2 h at 50 degrees C) followed by UNO Q-6 FPLC anion exchange chromatography, and submitted to biochemical characterization assays. Matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF/MS) analysis revealed that the purified enzyme was a monomer with a molecular mass of 33246.10 Da. The sequence of the 23 N-terminal residues of KERCA showed high homology with those of bacterial keratinases. Optimal activity was achieved at pH 7 and 50 degrees C. The enzyme was completely inhibited by phenylmethanesulfonyl fluoride (PMSF) and diiodopropyl fluorophosphates (DFP), which suggests that it belongs to the serine keratinase family. KERCA displayed higher levels of hydrolysis and catalytic efficiency than keratinase KERQ7 from Bacillus tequilensis strain Q7. These properties make KERCA a potential promising and eco-friendly alternative to the conventional chemicals used for the dehairing of goat, sheep, and bovine hides in the leather processing industry

Characterization of a purified thermostable xylanase from Caldicoprobacter algeriensis sp. nov. strain TH7C1(T)

The present study investigates the purification and biochemical characterization of an extracellular thermostable xylanase (called XYN35) from Caldicoprobacter algeriensis sp. nov., strain TH7C1(T), a thermophilic, anaerobic strain isolated from the hydrothermal hot spring of Guelma (Algeria). The maximum xylanase activity recorded after 24 h of incubation at 70 degrees C and in an optimized medium containing 10 g/L mix birchwood-and oats spelt-xylan was 250 U/mL. The pure protein was obtained after heat treatment (1 h at 70 degrees C), followed by sequential column chromatographies on Sephacryl S-200 gel filtration and Mono-S Sepharose anion-exchange. Matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF/MS) analysis indicated that the purified enzyme is a monomer with a molecular mass of 35,075.10 Da. The results from amino-acid sequence analysis revealed high homology between the 21 NH2-terminal residues of XYN35 and those of bacterial xylanases. The enzyme showed optimum activity at pH 11 and 70 degrees C. While XYN35 was activated by Ca2+, Mn2+, and Mg2+, it was completely inhibited by Hg2+ and Cd2+. The xylanase showed higher specific activity on soluble oat-spelt xylan, followed by beechwood xylan. This enzyme was also noted to obey the Michaelis-Menten kinetics, with Km and kcat values on oat-spelt xylan being 1.33 mg/mL and 400 min(-1), respectively. Thin-layer chromatography soluble oat-spelt xylan (TLC) analysis showed that the final hydrolyzed products of the enzyme from birchwood xylan were xylose, xylobiose, and xylotriose. Taken together, the results indicated that the XYN35 enzyme has a number of attractive biochemical properties that make it a potential promising candidate for future application in the pulp bleaching industry

Optimized production and characterization of a detergent-stable protease from Lysinibacillus fusiformis C250R

In this study, we aimed to optimize the cultural and nutritional conditions for protease production by Lysinibacillus fusiformis strain C250R in submerged fermentation process using statistical methodology. The most significant factors (gruel, wheat bran, yeast extract, and FeSO4) were identified by Plackett-Burman design. Response surface methodology (RSM) was used to determine the optimum levels of the screened factors and their interaction. Under the optimized conditions, protease yield 3100 U/mL was 4.5 folds higher than those obtained by the use of the initial conditions (680 U/mL). Additionally, a new extracellular 51 kDa-protease, designated SAPLF, was purified and biochemically characterized from strain C250R. It shows optimum activity at 70 °C and pH 10. Its half-life times at 70 and 80 °C were 10 and 6-h, respectively. Irreversible inhibition of enzyme activity of SAPLF with serine protease inhibitors demonstrated that it belongs to the serine protease family. Interestingly, its catalytic efficiency was higher than that of SPVP from Aeribacillus pallidus strain VP3 and Alcalase Ultra 2.5 L from Bacillus licheniformis. This study demonstrated that SAPLF has a high detergent compatibility and an excellent stain removal compared to Alcalase Ultra 2.5 L; which offers an interesting potential for its application in the laundry detergent industry

Interaction between maternal and offspring diet to impair vascular function and oxidative balance in high fat fed male mice

Aims: to determine the impact of maternal and post-weaning consumption of a high fat diet on endothelium-dependent vasorelaxation and redox regulation in adult male mouse offspring.Methods: female C57BL6J mice were fed an obesogenic high fat diet (HF, 45% kcal fat) or standard chow (C, 21% kcal fat) pre-conception and throughout pregnancy and lactation. Post-weaning, male offspring were continued on the same diet as their mothers or placed on the alternative diet to give 4 dietary groups (C/C, HF/C, C/HF and HF/HF) which were studied at 15 or 30 weeks of age.Results: there were significant effects of maternal diet on offspring body weight (p<0.004), systolic blood pressure (p = 0.026) and endothelium-dependent relaxation to ACh (p = 0.004) and NO production (p = 0.005) measured in the femoral artery. With control for maternal diet there was also an effect of offspring post-weaning dietary fat to increase systolic blood pressure (p<0.0001) and reduce endothelium-dependent relaxation (p = 0.022) and ACh-mediated NO production (p = 0.007). There was also a significant impact of age (p<0.005). Redox balance was perturbed, with altered regulation of vascular enzymes involved in ROS/NO signalling.Conclusions: maternal consumption of a HF diet is associated with changes in vascular function and oxidative balance in the offspring of similar magnitude to those seen with consumption of a high fat diet post-weaning. Further, this disadvantageous vascular phenotype is exacerbated by age to influence the risk of developing obesity, raised blood pressure and endothelial dysfunction in adult lif