DESCRIPTIONS OF ANTIBIOTICS 



311 



chloride, ether, and petroleum ether. Ultraviolet 

 absorption spectrum maxima at 215 niju (£'l?m 215) 

 and 257 to 258 m^ (^Icm 89) (methanol). Infrared 

 .spectrum given in reference 1. Po.sitive diazo re- 

 action. Negative ninhydrin, biuret, ToUen, FeCl:i , 

 and Fehling test.s. Stable to heating for 10 min- 

 ute.s at 100°C at pH 2.0 to 9.0. Rf value.s of 0.53 

 (water-saturated butanol) and 0.86 (phenol-water. 

 8:2). C = 54.215%; H = 7.57%; N = 0.43%. C-M,H,-y 

 N2O9 . Acid hydrolysi.s products include two nin- 

 hydrin-positive i)roducts, one of which may be 

 glycine. 



Biological actinlj/: Active against gram-positive 

 l)acteria and mycobacteria; moderately active on 

 fiuigi. Not active on gram-negative bacteria. No 

 activity on the ascitic form of Mhrlich carcinoma 

 in mice. 



Toxicity: LDjo (mice) 1 to 2 mg per kg intraperi- 

 toneally. 



Reference: I. Nakamura, S. c/ a/. J. Antil>iotics 

 (Japan) 10.\ : 248-253, 1957. 



M^ 



ttlii 



Produced by: Streptomyces luvendttlae strains (2), 

 Streptomyces sp. (4). 



Remarks: Two mycothricin complexes (A and B) 

 were described, each from a different S. lavendulae 

 strain and each varying in the number of compo- 

 nents present. Complex B contains streptothricin 

 and a component also present in ".streptothricin 

 VI"' (see streptothricin-like antibiotics). It also 

 •contains a component (IV) apparently unique to 

 the mycothricin complex (2, 4). 



Method of extraction: I. Culture-broth treated 

 with Darco G-60 at pH 2.5. Filtrate adjusted to 

 pH 7.5 and adsorbed onto fresh Darco. Elution 

 with 75 per cent ethanol. Eluate adjusted to pH 

 7.0 with IR-45 (OH^ form), concentrated in vacuo, 

 and precipitated with acetone. Freeze dried from 

 an aqueous solution (2). II. Broth acidified to 

 pH 3 with acetic acid and treated with oxalic acid 

 to remove the contaminating Ca"*"*" and Mg++. 

 Filtered. Chromatographed at pH 6.0 on IRC-50 

 l)uffered with ammonium acetate at pH 6.5. Eluted 

 with 10 per cent acetic acid. Active fractions 

 treated by passing through a column of IR-45 

 (OH" phase) to reduce pH to 4.0, lyophilized, and 

 taken up in water. P]vaporated to dryness in vacuo. 

 Solid taken up in absolute methanol, then preci]) 

 itated with acetone. Chromatographed on Darco 

 (;-60-Super-Cel (2:1) mixture from 0.5 .V HCl. 

 l^eveloped with distilled water to give Fractions 

 1 and 2, then with 70 per cent ethanol in 0.1 A' 

 HCl to give Fraction 3. Purified by salt conversion 

 (helianthate to hydrochloride). Component IV 



purified from Fraction 3 by adjusting to pH 4.0 by 

 passing through an IR-45 (OH" phase) column, 

 concentration in vacuo, and lyophilization. Puri- 

 fied by salt conversion (helianthate — * hydrochlo- 

 ride) (4). 



Chemical and physical properties: Couiplexes A 

 and B: Peptide-like, strong organic bases. Yellow - 

 brown powder. Hydrochlorides: Colorless, water- 

 solul)le substances. Heat -stable. Bases: Soluble in 

 water. Slightly soluble in methanol and ethanol. 

 Insoluble in n -butanol, benzene, ether, petroleum 

 ether, ethyl acetate, chloroform, and acetone. 

 Positive ninhydrin, Pauly, and biuret tests. Nega- 

 tive or inconclusive Fehling, Tollen, Molisch, 

 maltol, Sakaguchi, Alillon, and Hopkins-Cole 

 tests. More stable to heat in acid and neutral than 

 in alkaline solution.s. Destroyed by autoclaving at 

 15 pounds for 10 minutes. Complex A more stable 

 than Complex B. Acid hydrolysates contain five 

 to seven ninhydrin-positive products, including 

 /3-lysine, streptolidine, and serine. Component IV: 

 [a];'' = —1.1° (c = 0.526 per cent in water). Posi- 

 tive Benedict test after heating for 10 minutes. 

 Weakly positive anthrone test. Helianthate: I'urple 

 crystals; m.p. 200-205°C. Hydrochloride: White, 

 amorphous solid (1, 4). 



Biological activity: Complex A slightly more 

 active than B. Both are active against gram- 

 positive and gram-negative bacteria, fungi, and 

 yeasts (2). Active on the nematode Rhahditis 

 brigysae (5). Reduction, by seed treatment, of 

 Helminthosporium sp., Fusarium sp., and bac- 

 teria on wheat seeds (3). Complexes are more ac- 

 tive than streptothricin on B. mycoides, but less 

 so on Ps. fluorescens. Mycothricins are more active 

 on fungi and yeasts than all other streptothricins 

 except pleocidin (1, 2). Component IV: three to 

 ten times more active than the complex on bac- 

 teria and 30 times more active on ('. tropicalis 

 and Sacch. cercvisiae (4). 



Toxicity: LD50 (mice) 65 to 130 mg per kg (Com- 

 plex A) and 32.5 mg per kg (Complex B) subcu- 

 taneously. Delayed toxicity typical of the strep- 

 tothricin group. Not irritating to the rabbit 

 conjunctiva at levels which give reddening and 

 pus with streptothricin (2). Nontoxic to tomato, 

 cucumber, and wheat at 5000 ppm (seeds), 2500 

 ppm (foliage spray), or 500 ppm (tomato and cu- 

 cumber in li(iuid culture) (3). 



References: 



1. Schaff'ner, C. P. et al. Resumes 2nd Congr. 



Intern. Biochem., Brussels 95, 1955. 



2. Rangaswami, G. et al. Antibiotics & Chem- 



therapy 6: 675-683, 1956. 



3. Rangaswami, G. Plant Disease Reptr. 40: 



483-487, 1956. 



