Streptomyces species other strains

The tetracyclines are a group of antibiotics with the same basic chemical structure they are derivatives of the naphthacene ring system. Compounds of the series differ in the composition of the side chains (Fig. 1). These antibiotics derived from different Streptomyces species show closely related spectra of bacteriostatic properties, with the exception of minocycline, which is very effective against most Staphylococcus strains resistant to other tetracyclines. Absorption, metabolism, and excretion of the different tetracyclines vary, however. After oral application, tetracycline, oxytetracycline, and chlortetracycline are absorbed to a much lesser degree than demethylchlortetracycline, methacycline, or the almost entirely absorbed minocycline. Maximum blood levels are found 2-6 h after oral intake and immediately in the case of intravenous infusion. Half-lives between 8 and 15 h were reported. The tetracyclines diffuse readily across the vascular barrier and are found in various tissues such as the liver, spleen, bone marrow, kidney, skin, and lungs as well as the peritoneal and pericardiac cavities. The tetracyclines are also able to... 

Bacteria. Multitude of strains producing a wide variety of large and small 250 molecule products. While Escherichia coli is the preferred host for therapeutic proteins, numerous other commercial expression systems are available for small molecule production. Streptomyces species are the preferred hosts for secondary metabolites... 

Figure 1 Scanning electron micrograph of a novel Strepto-myces species from which compound (I) and many other related milbemycins have been isolated. (See Baker GH, Dorgan RJJ, Everett JR, Hood JD, and Poulton ME (1990) A novel series of milbemycin antibiotics from Streptomyces strain E225. II. Isolation, characterisation, structure elucidation and solution conformations. Journal of Antibiotics 43 1069-1076.)...

In 1959, Horiguchi and Kandatsu discovered the first naturally occurring compound with the C—P bond, 2-aminoethylphosphonic acid. A decade later, a potent antibiotic produced by strains Streptomyces, phosphonomycin, was found, with a unique structural feature consisting of a phosphonic acid moiety attached to an oxirane system. Since that time, other alkylphosphonic acids, phospho-nolipids, and phosphinates have been detected as minor components in various living species." Interestingly, alkylphosphonic acid derivatives were also found in meteorites. ... 

This acid has been found only once in a strain of Streptomyces (Nakao et al, 2000b). Other derivatives containing an aziridine nucleus are present in some species of Dysidea (see below). 

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