n.
Any of the threadlike bacteria that make up the genus Streptomyces , occurring in soil and water.
These gram-positive (see gram stain ), oxygen-requiring bacteria form a branching net called a mycelium that bears chains of spore s at maturity. Many species are important in the decomposition of organic matter in soil, contributing in part to the earthy odour of soil and decaying leaves and to the fertility of soil. Certain species produce antibiotic s such as tetracycline and streptomycin . See also actinomycete .