Antibiotic substances

Beginning in the 1980s research directed toward the isolation of new drugs derived from natural sources identified a family of tumor inhibitory antibiotic substances characterized by novel struc tures containing a C C—C=C—C C unit as part of a nine or ten membered ring With one double bond and two triple bonds (-ene + di- + -yne) these com pounds soon became known as enediyne antibiotics The simplest member of the class is dynemian A most of the other enediynes have even more compli cated structures... 

Terreic acid is a naturally occumng antibiotic substance Its actual structure is an enol iso mer of the structure shown Wnte the two most stable enol forms of terreic acid and choose which of those two IS more stable... 

Polyether (Section 16.4) A molecule that contains many ether linkages. Polyethers occur naturally in a number of antibiotic substances. 

The process for producing spiramycin comprises inoculating an aqueous nutrient medium with a culture of the NRR L No. 2420, allowing aerobic fermentation to take place and separating from the culture medium the spiramycin thus formed. The culture medium also contains the antibiotic substance known as Congocidin which, however, does not possess the same useful properties as spiramycin and which can be isolated in crystalline form. The separation of the two antibiotic substances is readily achieved. 

The first of the antibiotics that found practical use as a therapeutic was penicillin. The success of penicillin initiated a vast screening process all over the world, which resulted in the isolation of a large number of antibiotic substances from various natural sources. Many of these compounds were produced by micro-organisms and prove to be lethal for other micro-organisms. Many of these compounds were also very toxic to humans and could not be used therapeutically. Nevertheless a large number of classes of useful compounds were produced. The chemical structures of members of some of the most important classes are shown in Figure 6.1. 

Antibiotic substances and their molecular genetics are summarized for the best studied system of fluorescent Pseudomonas, producing up to. seven different compounds. Similar extensive studies should be done for other important rhizosphere bacteria as potential important antagonists for root pathogens. The best-studied example for the effects of vitamins in the rhizosphere is biotin. The molecular genetics of production and uptake of vitamins in the plant-microbe interaction is also a field of interesting future work. 

K. Mulya, M. Watanabe, M. Goto, Y. Takikawa, and S. Tsuyuniu, Suppression of bacterial wilt di.sease in tomato by root-dipping with P.seudomonas fluorescens PfG32 The role of antibiotic substances and siderophore production. An. Phytopath. Soc. Jpn. 62 (1996). 

Antibiotic Substances Produced by Three Species of Basidiomycetes. Arch. Biochemistry 25, 208 (1950). 

Kavanagh, F., A. Hervey and W. J. Robbins Antibiotic Substances from... 

Antibiotic Substances from Basidiomycetes. VI. Agrocybe dura. 

The microorganism Streptomyces halstedii elaborates an antibiotic substance, called carbomycin32 or Magnamycin,33 which has been isolated from the fermentation broth by simple, solvent extraction, and then purified by recrystallization. (Examination of the resulting mother liquors has led to the isolation of a closely similar compound designated as Magnamycin B. 34) Carbomycin has low toxicity,85 and appears to be an effective and satis-... 

Vigorous acid hydrolysis of the Magnamycin antibiotic substances yields a deoxydimethylamino sugar (XXI) termed mycaminose. The oxidation of this compound with one mole of periodate per mole leads43 to the generation of formic acid plus another deoxydimethylamino sugar (XXII). 

TSCHESCHE, R., Advances in the chemistry of antibiotic substances from higher plants. In Pharmacognosy and Phytochemistry, (H. Wagner and L. Horhammer, eds,), Springer-Verlag, Berlin. 1971, pp. 274-289. 

Chlortetracycline hydrochloride (CTC-HCL) is the hydrochloride salt of an antibiotic substance produced by the growth of Streptomyces aureofaciens (Fam. Streptomycetaceae). 

Antibiotics Substances produced by and obtained from living cells, such as bacteria or molds. Examples of antibiotics would include penicillin and streptomycin. 

Kavanagh F, Hervey A, Robbins WJ. (1950) Antibiotic substances from Basidiomycetes VI. Agrocybe Dura. Proc Natl Acad Sci USA 36 102-106. 

Three broad groupings, of the antibiotic substances presently used in animal production, include (a) broad-spectrum antibiotics, including penicillins and tetracyclines, which are effective against a wide variety of pathogenic and non-pathogenic bacteria (b) several narrow-spectrum antibiotics that are not used in human medicine and. (c) the ionophore antibiotics, monensin. lasalocid and salinomycin Monensin and lasalocid are used as rumen fermentation regulators in beef cattle, and the three ionophores are used as coccidiostats in poultry production. The ionophores. which are not used in human medicine, were first introduced in the 1970 s and account for most of the increase in antibiotic usage in animal production since the 1960 s. 

High voltage electrophoresis (HVE) in agar gel with detection by bioautography has been used with considerable success in some laboratories for identification of residues (1-6). This procedure has the advantage that all antibiotic substances detectable by bioautography can be classified on the basis of electrophoretic mobility. Further testing may be required for quantification and to... 

---