BIOCHEMICAL, NUTRIENT AND INHIBITORY CHARACTERISTICS OF <i>STREPTOMYCES</i> CULTURED FROM A HYPERSALINE ESTUARY, THE LAGUNA MADRE (TEXAS)

Abstract

<i>Streptomyces</i> are common soil bacteria that produce secondary metabolites, including several antibiotics; however, the characteristics of marine <i>Streptomyces</i> are largely unknown. Sediment samples were taken from 3 sites in the Laguna Madre to isolate marine <i>Streptomyces</i>. Sediment was diluted, spread onto synthetic seawater media to estimate the total bacterial density of the samples and spread onto starch casein agar to isolate <i>Streptomyces</i>. Isolated <i>Streptomyces</i> were tested for salinity tolerance and optimal growth pH. Isolates were assayed using API 20E^® test strips and BIOLOG^™ plates to construct biochemical profiles and assess nutrient utilization abilities of the bacteria, respectively. Individual <i>Streptomyces</i> were tested for the ability to inhibit the growth of other isolated <i>Streptomyces</i> (i.e., interference competition) and putatively identified by DNA sequencing. Results showed that there was no significant difference in microbial density in sediments from the 3 sampling sites. Eleven (11) <i>Streptomyces</i> pure cultures were obtained in total; most tolerated salinity up to 60 ppt and grew optimally at pH 7.5. Biochemical profile comparisons showed that the <i>Streptomyces</i> were only at least 74% similar; most (8/11) were >90% similar. Isolates could use between 87-95 carbon sources. Three (3) isolates displayed interference toward other isolates. Ten (10) isolates were identified as <i>Streptomyces griseus</i> by DNA sequencing. Laguna Madre <i>Streptomyces</i> organisms display some diverse characteristics with regards to their halotolerance, biochemical profiles, carbon source utilization and inhibition toward other organisms. Further investigations may yield greater understanding of these organisms in this and other marine environments and may be a reservoir of novel microorganisms and secondary metabolites

Marine Actinobacteria as a source of compounds for phytopathogen control: An integrative metabolic-profiling / bioactivity and taxonomical approach

“…Other biochemical characteristics such as fermentation or oxidation of sugars (glucose, manitol, inositol, sorbitol, rhamnose, sucrose, melibiose, amygdalin and arabinose); enzyme activity (β-galactosidase, arginine-dihydrolase, lysine decarboxylase, ornithine decarboxylase, ureasae, tryptophan deaminase, gelatinase); citrate utilization; production of sulfide, indole and acetoin; and nitrate reduction were tested with the API 20E kit (bioMérieux Inc., Durham, NC) ( S1 Table ). The results were compared with those described for other Actinobacteria -like bacteria [ 31 ].…”

Characteristics of marine strain Streptomyces sp. with antimicrobial and cytotoxic activity

“…Catalase and oxidase activities (Bactident Oxidase MERKC) were determined as proposed for Streptomyces-like bacteria (Goodfellow, 2012;Espinoza et al, 2013). The ability to synthesize the enzymes amylase, protease, gelatinase, lipase, urease, cellulase, nitrate reductase, and to produce hydrogen sulfide was determined using the API 20E kit (bioMérieux, Inc., Durham, NC).…”