Brevibacillus gelatini sp. nov., isolated from a hot spring.

Two Gram-stain-positive, moderately thermophilic, endospore-forming, rod-shaped, motile bacteria designated PDF4T and PDF10, were isolated from Camkoy hot spring in the provinces of Aydin, Turkey and were characterized in order to determine their phylogenetic position. 16S rRNA gene sequence analysis revealed that the two strains belonged to the genus Brevibacillus. Strain PDF4T showed highest 16S rRNA gene sequence similarity to strain PDF10 (99.5 %), Brevibacillus brevis DSM 30T (98.9 %), Brevibacillus parabrevis DSM 8376T (98.6 %) and Brevibacillus formosus DSM 9885T (98.5 %); similarities to other species of the genus Brevibacillus were less than 98.5 %. The predominant fatty acids of strain PDF4T were anteiso-C15 : 0 (60.0 %) and iso-C15 : 0 (22.3 %). The polar lipids of strain PDF4T consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylmonomethylethanolamine, an unknown phospholipid, two unknown lipid, an unknown aminophospholipid and two unknown aminolipids. MK-7 was detected as a sole respiratory quinone, and the cell wall of strain PDF4T contained meso-diaminopimelic acid. The DNA G+C content of strain PDF4T was 51.7 mol%. DNA-DNA hybridization showed less than 60 % relatedness between strain PDF4T and type strains of the most closely related species given above. Based on these data, the two strains are considered to represent a novel species of the genus Brevibacillus, for which the name Brevibacillus gelatini sp. nov. is proposed. The type strain is PDF4T ( = NCCB 100559T = DSM 100115T).

Cloning, expression and biochemical characterization of a ß-carbonic anhydrase from the soil bacterium Enterobacter sp. B13.

A recombinant carbonic anhydrase (CA, EC 4.2.1.1) from the soil-dwelling bacterium Enterobacter sp. B13 was cloned and purified by Co(2+) affinity chromatography. Bioinformatic analysis showed that the new enzyme (denominated here B13-CA) belongs to the ß-class CAs and to possess 95% homology with the ortholog enzyme from Escherichia coli encoded by the can gene, whereas its sequence homology with the other such enzyme from E. coli (encoded by the cynT gene) was of 33%. B13-CA was characterized kinetically as a catalyst for carbon dioxide hydration to bicarbonate and protons. The enzyme shows a significant catalytic activity, with the following kinetic parameters at 20 °C and pH of 8.3: kcat of 4.8 × 10(5) s(-1) and kcat/Km of 5.6 × 10(7) M(-1) × s(-1). This activity was potently inhibited by acetazolamide which showed a KI of 78.9 nM. Although only this compound was investigated for the moment as B13-CA inhibitor, further studies may reveal new classes of inhibitors/activators of this enzyme which may show biomedical or environmental applications, considering the posssible role of this enzyme in CaCO3 biomineralization processes.

Algoriphagus trabzonensis sp. nov., isolated from freshwater, and emended description of Algoriphagus alkaliphilus.

A Gram-staining-negative, non-motile, catalase- and oxidase-positive strain, designated MS7(T), was isolated from freshwater of a river near Trabzon, Turkey. Its taxonomy was investigated using a polyphasic approach. The strain grew optimally at 28 °C and pH 7.5 and in the presence of 2.0% NaCl. 16S rRNA gene sequence analysis revealed that the strain belonged to the genus Algoriphagus; strain MS7(T) showed highest sequence similarity to the type strains of Algoriphagus alkaliphilus (97.3%), Algoriphagus terrigena (96.8%), Algoriphagus jejuensis (96.2%), Algoriphagus boritolerans (96.1%) and Algoriphagus aquatilis (95.8%). The major fatty acids of strain MS7(T) were iso-C15 : 0 (30.14%) and summed future 9 (10-methyl C16 : 0 and/or iso-C17 : 1ω9c 18.75%). Polar lipid analysis revealed phosphatidylethanolamine, a variety of unidentified lipids, an unidentified aminophospholipid, an unidentified phospholipid and an unidentified aminolipid. The major isoprenoid quinone was MK-7.The DNA G+C content of MS7(T) was 41.6 mol%, a value consistent with that of members of the genus Algoriphagus. The level of DNA-DNA relatedness between strain MS7(T) and A. alkaliphilus LMG 22694(T) was 41%, which is clearly below the 70% threshold accepted for species delineation. Thus, our results support the placement of strain MS7(T) within a separate and previously unrecognized species. On the basis of these data, the strain is considered to represent a novel species of the genus Algoriphagus, for which the name Algoriphagus trabzonensis sp. nov. is proposed. The type strain is MS7(T) ( = NCCB 100372(T) = LMG 26290(T)). An emended description of A. alkaliphilus is also provided.