Shewanella submarina sp. nov., a gammaproteobacterium isolated from marine water.

A curved-rod-shaped bacterium was isolated from a marine (100 m depth) water sample collected from Bay of Bengal, Visakhapatnam, India. Strain NIO-S14T, was Gram-stain-negative, motile and pale-yellow. NIO-S14T was able to grow aerobically and anaerobically and could utilize a number of organic substrates. Major fatty acids were C12 : 0, iso-C13 : 0, C14 : 0, iso-C15 : 0, C16 : 0 and C16 : 1ω7c and/or C16 : 1ω6c (summed feature 3). NIO-S14T contained diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, two unidentified aminophospholipids and six unidentified lipids as polar lipids. The DNA G+C content of NIO-S14T was 47.9 mol%. The 16S rRNA gene sequence comparisons indicated that the isolate represented a member of the family Shewanellaceae within the class Gammaproteobacteria. According to the results of 16S rRNA gene sequence analysis, NIO-S14T was closely related to Shewanella coralliiwith a pair-wise sequence similarity of 99.26 %. On the basis of the sequence comparison, NIO-S14T clustered with Shewanella coralliiand together they clustered with Shewanella mangroviand seven other species of the genus Shewanella but were distantly related. DNA-DNA hybridization between NIO-S14T and Shewanella corallii DSM 21332Trevealed a relatedness of 35 %. Distinct morphological, physiological and genotypic differences from these previously described taxa supported the classification of NIO-S14T as a representative of a novel species of the genus Shewanella, for which the name Shewanellasubmarina sp. nov. is proposed. The type strain of Shewanellasubmarina is NIO-S14T (=MTCC 12524T=KCTC 52277T=LMG 30752T).

Perennial occurrence of heterotrophic, indicator and pathogenic bacteria in the coastal Bay of Bengal (off Visakhapatnam) - Impact of physical and atmospheric processes.

In order to examine the health of the coastal waters off Visakhapatnam in terms of prevalence and abundance of heterotrophic (H), indicator and pathogenic (P) bacterial counts (BC) and influence of physical processes on them, time-series observations were conducted during January (winter), March (spring), July (summer) and October (post-monsoon). We noticed the impact of physical forces on substantial variations in abundance and distribution of the HBC, total coliforms, Enterococcus faecalis and Pseudomonas aeruginosa in the study region. Based on our results Escherichia coli and other PBC were not much influenced by the physical conditions. It has been noticed that the perennial existence of the high abundance of IBC and PBC above the standard limits during the entire study period leading to an alarming situation in the coastal waters off Visakhapatnam.