Streptomycetaceae: Life Style, Genome, Metabolism and Habitats

Hildgund Schrempf, University Osnabrück, Osnabrück, Germany

Published online: July 2008

DOI: 10.1002/9780470015902.a0020393

Full Article on Wiley Online Library

A huge number of Streptomyces species belong to the family Streptomycetaceae. They are abundant soil bacteria with a highly complex life cycle. They have a large linear chromosomal deoxyribonucleic acid (DNA) which can be accompanied by circular and linear plasmids. They have an amazing capacity to contribute to the bioconversion of many different compounds including biopolymers, which are important for recycling processes in nature and have many biotechnological applications. They modify and synthesize thousands of chemically diverged secondary metabolites, many of which inhibit various cellular processes. Numerous of these are in use to cure diseases which are due to pathogenic microorganisms, parasites or the proliferation of tumour cells. Designed tailoring of genes encoding these metabolites has begun to complement traditional screening methods for new biologically active substances.

Keywords: streptomycetes; life cycle; genetic information; primary and secondary metabolites; ecology

	Figure 1. Stages of growth. Two round spores (top, left) had started to form small germ tubes, and subsequently (left, bottom) elongated (magnification 2000-fold). Then a large network of substrate hyphae (also named substrate mycelium) was build (centre, magnification 400-fold, fluorescence microscopy). Owing to differential uptake of specific dyes, outgrowing spores and hyphae have a green fluorescence and dead hyphae (in the centre of the mycelium) appeared. Finally aerial hyphae developed, in which spores arose (right, magnification 20 000-fold, transmission electron microscopy).
	Figure 2. Types of DNA. The linear chromosome (black, top) has a central replication origin (red), from which bidirectional replication is initiated (red arrows). Each of the telomeric ends interacts with a specific protein (grey). Regions, which differ mostly among different strains, or in which preferentially deletions and/or amplifications take place, are marked (broken lines). In addition to the chromosome, the strains may contain one or several types of circular plasmid(s) (bottom, left) and/or one or several type(s) of linear plasmids with telomeric ends interacting with a specific protein.
	Figure 3. Degradation capacities. Fungal hyphae (bottom, control) were exposed to secreted Streptomyces enzymes. As a result, fungal hyphae were destructed as evidenced by the hole-structures by scanning microscopy (magnification 1500-fold).
	Figure 4. Growth within the soil. Using scanning microscopy, Streptomyces hyphae were detected within soil (magnification 4000-fold).
	Figure 5. Enrichment from soil. A soil sample was pretreated with phenol (to select for spores) and plated to a selective medium plate. As a result, a diversity of colonies (some pigmented) arose, and most of them appear elevated due to the formation of aerial hyphae and spores. The dark-blue background is due to pigments, which were secreted by some colonies and which diffused (magnification 3-fold).

Further Reading
	Baltz RH (2006) Molecular engineering approaches to peptide, polyketide and other antibiotics. Nature Biotechnology 24: 1533–1540.
	Chater KF and Chandra G (2006) The evolution of development in Streptomyces analysed by genome comparisons. FEMS Microbiology Reviews 30: 651–672.
	Gao B, Paramanathan R and Gupta RS (2006) Signature proteins that are distinctive characteristics of Actinobacteria and their subgroups. Antonie Van Leeuwenhoek 90: 69–91.
	Horinouchi S (2007) Mining and polishing of the treasure trove in the bacterial genus Streptomyces. Bioscience, Biotechnology, and Biochemistry 71: 283–299.
	book Korn-Wendisch F and Kutzner HJ (1992) "The family Streptomycetaceae" In: Balows A, Trüper HG, Dworkin M, Harder W and Schleifer KH (eds), The Prokaryotes: A Handbook on Habitats, Isolation and Identification of Bacteria, vol. 1 pp. 921–995. Berlin: Springer.
	book Schrempf H (2007) "The family of Streptomycetacae: Part II molecular biology" In: Dworkin M, Falkow S, Rosenberg E, Schleifer KH and Stackebrandt E (eds), The Prokaryotes, vol. 3 pp. 605–622. Berlin: Springer.

Article Title:	Streptomycetaceae: Life Style, Genome, Metabolism and Habitats
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Streptomycetaceae: Life Style, Genome, Metabolism and Habitats

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