Characterization of microorganisms from Sitakunda hot spring

Water, leaf, stone and sand samples from Sitakunda hot spring were studied and the microorganisms isolated from these samples were thoroughly characterized. The pH of the collected samples was found to range from 8.5 to 8.9 and the recorded temperature varied from 26.1 to 29.8 ºC during winter season. BOD of the collected water samples ranged from 10 to 92 mg/L, while COD was almost zero. The total alkalinity and chlorine content ranged from 12 to 20 mg/L and 13.9 to 18.3 gm/L respectively. Quantitative enumeration of bacterial population showed the range of 8.0×102 to 3.8×105 cfu/ml or gm sample. All the 9 selected isolates were identified as Bacillus coagulans (S1B4), Bacillus laterosporus (SB18), Bacillus megaterium (S2B11), Bacillus popilliae (S4P1), Bacillus firmus (S5B1), Citrobacter intermedius (S4B17), Listeria monocytogenes (S1B1), Listeria denitrificans (S2B) and Pseudomonas mendocina (S4P3). Bacillus laterosporus, Bacillus megaterium and Listeria denitrificans showed better growth in presence of methane gas in nutrient broth. By direct microscopic observation 7 genera of cyanobacteria (Arthrospria, Microcoleus, Oscillatoria, Schyzothrix, Scytonema, Nostoc and Gloeocapsa) and 4 genera of diatoms (Gomphonema, Melosira, Navicula and Pinnularia) were detected in the water sample DOI: http://dx.doi.org/10.3329/cujbs.v4i1.13394 The Chittagong Univ. J. B. Sci.,Vol. 4(1&2):107-117, 2009

Conjugative transposition of Tn916 and Tn925 in Bacillus popilliae

Interspecies transfer of the conjugative transposons Tn916 and Tn925 into B. popilliae Pj1 occurred using Enterococcus faecalis and Bacillus subtilis CU4049 as transposon donors. Tn916 was stably maintained in B. popilliae Pj1 following growth without selective pressure and was successfully introduced into the plasmid-containing B. popilliae strains NRRL B-2524, Ch1, and KLN4 using E. faecalis CG110. In B. popilliae, expression of the tetracycline resistant determinants on Tn916 and Tn925 provided resistance to 25 μg/mL and 50 μg/mL tetracycline, respectively. An erythromycin resistant determinant, present in Tn916ΔE, was also functional in B. popilliae Pj1 and provided resistance to 1 mg/mL erythromycin. Transfer of Tn916 into E. faecalis, B. subtilis, and between B. popilliae strains was accomplished using a transposon-containing strain of B. popilliae as donor. Efforts to transfer Tn916 between E. coli and B. popilliae were unsuccessful. Key words: Bacillus popilliae, milky disease, Tn916, conjugative transposon.