Genetic Diversity in Microorganisms

Genetic Diversity in Microorganisms presents chapters revealing the magnitude of genetic diversity of microorganisms living in different environmental conditions. The complexity and diversity of microbial populations is by far the highest among all living organisms. The diversity of microbial communities and their ecologic roles are being explored in soil, water, on plants and in animals, and in extreme environments such as the arctic deep-sea vents or high saline lakes. The increasing availability of PCR-based molecular markers allows the detailed analyses and evaluation of genetic diversity in microorganisms. The purpose of the book is to provide a glimpse into the dynamic process of genetic diversity of microorganisms by presenting the thoughts of scientists who are engaged in the generation of new ideas and techniques employed for the assessment of genetic diversity, often from very different perspectives. The book should prove useful to students, researchers, and experts in the area of microbial phylogeny, genetic diversity, and molecular biology

Spatial specificity of H2O2-generating oxalate oxidase gene expression during wheat embryo germination

Germin, a molecular marker of wheat embryo germination, is a protease-resistant, apoplastic, homopentameric glycoprotein with peroxide-generating oxalate oxidase activity. The spatial specificity of germin-like oxalate oxidase (gl-OXO) gene expression has been determined in tissues of germinating wheat embryos by a combination of histochemical, immunocytochemical and in situ hybridization techniques. The synthesis and accumulation of gl-OXO mRNA and protein is localised within the enveloping tissues of the embryonic axis (particularly the coleorhiza) during the first 24 h of imbibition. By 48 h germination, gl-OXO accumulation is detected throughout the root, with the exception of the postmitotic zone of cell elongation, where accumulation of its transcript is restricted to outer cell layers. At this time in the elongating shoot, gl-OXO is restricted to the coleoptile where it is detected only in the epidermal cell layer, the vascular bundles and bundle sheath cells. In older seedlings (approximately 9 days post-imbibition) gl-OXO activity is detected in leaves, but only within the vascular bundles. These patterns of expression are consistent with the hypothesis that the biological function of gl-OXO is to restrict cell growth by participating in cell-wall restructuring through the local provision of hydrogen peroxide for cross-linking of wall components

Isolation, Characterization and Phylogenetic Analysis of Halophilic Archaea from a Salt Mine in Central Anatolia (Turkey)

The haloarchaeal diversity of a salt mine, a natural cave in central Anatolia, was investigated using convential microbiological and molecular biology methods. Eight halophilic archaeal isolates selected based on their colony morphology and whole cell protein profiles were taxonomically classified on the basis of their morphological, physiological, biochemical properties, polar lipid and protein profiles and 16S rDNA sequences. From the 16S rDNA sequences comparisons it was established that the isolates CH2, CH3 and CHC resembled Halorubrum saccharovorum by 98.8%, 98.9% and 99.5%, respectively. There was a 99.7% similarity between the isolate CH11 and Halobacterium noricense and 99.2% between the isolate CHA1 and Haloarcula argentinensis. The isolate CH8K and CH8B revealed a similarity rate of 99.8% and 99.3% to Halococcus dombrowskii, respectively. It was concluded that the isolates named CH2, CH3 and CHC were clustered in the genus Halorubrum and that CHA1 and CH7 in the genus Haloarcula, CH8K and CH8B in the genus Halococcus and CH11 in the genus Halobacterium

Antimicrobial and Antioxidant Activities of Various Extracts of Verbascum antiochium Boiss. (Scrophulariaceae)

Verbascum antiochium Boiss., a member of the Scrophulariaceae family, is endemic to Turkey. The extracts obtained from V. antiochium by increased polarity and direct methanol extraction were tested by the agar well diffusion method against various Gram-positive and Gram-negative bacteria and one fungus. The methanol/water extract exhibited a larger inhibition zone against both the Gram-negative and Gram-positive bacteria than the other extracts. Haemophilus influenzae was found to be the most sensitive bacterium among the bacteria tested. The antioxidant activities of the methanolic extract of V. antiochium were examined by two complementary test systems. The 50% inhibition activity of the methanolic extract of V. antiochium against the free radical 2,2-diphenyl-1-picrylhydrazyl was determined as 4.80 mg/mL. In the case of the linoleic acid system, oxidation of linoleic acid was inhibited by the methanolic extract of V. antiochium with 79.92% inhibition, which is close to the value of the synthetic antioxidant reagent, tert-butylated hydroxytoluene. The total phenolic components of V. antiochium were determined to be 92.71 mg of gallic acid equivalents/g. Iridoid glycosides, flavonoids, and saponins were detected as the major chemical constituents in the extract

Characterization of extracellular esterase and lipase activities from five halophilic archaeal strains

A total of 118 halophilic archaeal collection of strains were screened for lipolytic activity and 18 of them were found positive on Rhodamine agar plates. The selected five isolates were further characterized to determine their optimum esterase and lipase activities at various ranges of salt, temperature and pH. The esterase and lipase activities were determined by the hydrolysis of pNPB and pNPP, respectively. The maximum hydrolytic activities were found in the supernatants of the isolates grown at complex medium with 25% NaCl and 1% gum Arabic. The highest esterase activity was obtained at pH 8-8.5, temperature 60-65A degrees C and NaCl 3-4.5 M. The same parameters for the highest lipase activities were found to be pH 8, temperature 45-65A degrees C and NaCl 3.5-4 M. These results indicate the presence of salt-dependent and temperature-tolerant lipolytic enzymes from halophilic archaeal strains. Kinetic parameters were determined according to Lineweaver-Burk plot. The KM and V (max) values were lower for pNPP hydrolysis than those for pNPB hydrolysis. The results point that the isolates have higher esterase activity comparing to lipase activity