[Isolation and characterization of streptomyces in composted Iranian soil, using chemotaxonomy]

ABSTRACT

The Actinomycetes are gram-positive organisms that tend to grow slowly as branching filaments. They were thought to be related to both bacteria and fungi, but in recent years it has been undoubtedly shown that they are prokaryotic organisms. Actinomycetes have proved to be causal agents of many human and animal infections. They also play as an important rule in producing new antibiotic agents. Fifty soil samples collected from different regions of the country were analyzed to determine the presence and types of antibiotic-producing Streptomycetes using dilution plating method. Starch casein agar and glucose yeast extract agar were used as the culture media. 88 selected organisms from 140 isolates were subjected to chemotaxonomy determination. The isomeric form of diaminopimelic acid [DAP] was determined by thin-layer chromatography [TLC] of hydrolyzed whole-organism preparations. A sample of the hydrolysated extract was applied as a 2[cm] band from the base of the TLC plates. A standard containing meso and LL-DAP was also run at both sides of the sheet for comparison with test mixtures. The plates were developed for about 3 [1/2] hours in a glass tank containing 40 ml methanol, 2 ml 6Mol HCl, 5ml Pyridine, and 13 ml water. DAP appears as green/brown spots, changing to yellowish with time. The LL-DAP, meso-DAP and hydroxy-DAP isomers have approximate R[f] values. Approximately 97% of test strains contained LL-DAP and the remaining 3%, contained meso-DAP. This study demonstrated a wide variety of Streptomycetes bacteria isolates which are capable to produce antibiotics and TLC is an appropriate method in determination of Them