262 



DESCRIPTIONS OF ANTIBIOTICS 



0.30 and 0.70 (t-l)Utanol-\vater, 4:1). Endutnyrin 

 A: Ultraviolet absorption spectrum maxima at 

 about 292, 308, and 320 mjj. Endomynn B: LTltra- 

 violet absorption spectrum ma.xima at 338, 359, 

 and 380 m/x (13). 



Biological activity: Active on fungi, bacteria, 

 and Trypanosoma cruzi. More active on yeast-like 

 fungi (0.25 to 10 ^g per ml) than on filamentous 

 fungi (10 to 13 /ng per ml). More active on gram- 

 positive than on gram-negative bacteria. Some 

 activity on T . cruzi infections in mice (2, 4). Active 

 (not fungicidal) on C. albicans in tissue culture 

 and lytic to Trichomonas vaginalis in vitro (5, 6). 

 Controls leaf rust of wheat (3), strawberry fruit 

 rot (Botrytis cinerea) (10), and turf brown jjatch 

 (Rhizoctonia solani) (9); provides partial protec- 

 tion against Pseudoperonospora cnbensis (11). 

 Some control of bean root rot (14) and downj^ 

 mildew of broccoli {Peronospora parasitica (15)). 

 Antifungal activity enhanced l)y the neomycins 

 (16). 



Toxicity: Mice tolerate 0.5 gm per kg but not 

 1 gm per kg (no route given) (2). The LID (least 

 injurious dose) to tissue cultures of chick heart, 

 spleen cells, and human skin are 100 to 200 jug 

 per ml, 100 to 200 ^g per ml, and 50 to 100 ^g per 

 ml, respectively (5, 6). Produces some al)normali- 

 ties in Allium cepa roots at 100 ppm (1). Nontoxic 

 as 10,000-ppm spray to wheat, tomato, or liean 

 plants (3). 



Utilization: Control of plant diseases. 



References: 



1. Wilson, G. B. J. Heredity 41: 226-231, 



1950. 



2. Gottlieb, D. ct al. Phj'topathology 41: 



393-400, 1951. 



3. Anderson, H. W. and Gottlieb, D. Econ. 



Botany 6: 294-308, 1952. 



4. Packchanian, A. Am. J. Trop. Med. Hyg. 



2: 243-253, 1953. 



5. Hu, F. et al. A.M.A. Arch. Dermatol. 



Syphilol. 70: 1-15, 1954. 

 (). Wilkins, J. R. and Hen.shaw, C. T. Exptl. 

 Parasitol. 3:417-424,1954. 



7. Pomerat, C. M. and Leake, C. D. Ann. N. 



V. Acad. Sci. 58: 1110-1124, 1954. 



8. British Patent 705,622, May 17, 1954. 



9. Shurtleff, M. C. Phytopathology 45: 186, 



1955. 



10. Horn, N. L. Phytopathology 46: 15, 1956. 



11. Ark, P. A. and Thompson, J. P. Phyto- 



l)athology 46: 634, 1956. 



12. Tresner, H. D. and Backus, E. J. Appl. 



Microbiol. 4: 243-250, 1956. 



13. Vining, L. C. and Taber, W. A. Can. J. 



Chem. 35: 1461-1466, 1957. 

 14.- Davison, A. D. and Vaughn, J. R. Plant 



Disease Reptr. 41 : 432-435, 1957. 



15. Natti, J. J. Plant Disease Reptr. U: 



780-788, 1957. 



16. Sokolski, W. T. and Burch, M. R. Anti- 



biotics & Chemotherapy 10: 157-162, 

 1960. 



Eiidoniyciii-Iike Complex, Ilelixiiis 



Produced by: Streptomyces sp. (1). 



Method of extraction: Precipitate formed in 

 filtered liroth at pH 3.0; extracted with ethanol. 

 Extract concentrated in vacuo; heli.xin precipitates 

 out as a red gum on addition of chloroform (1). 

 Gum dissolved in absolute ethanol, and water 

 added. Mixture filtered and extracted with ethyl- 

 ene dichloride to remove helixin C. Aqueous etha- 

 nol layer concentrated under reduced pressure 

 and extracted with diethyl ether following addi- 

 tion of NaHCOg . Aqueous layer acidified to pH 

 3.0 and precipitate filtered off and taken up in 

 absolute ethanol. Ethanol solution extracted with 

 ethyl acetate and filtered. Filtrate dried in vacuo. 

 By dissolving this preparation in 0.06 A' NH4OH 

 and extracting with 1:1 n-butanol-ethyl acetate, 

 helixin b is obtained, contaminated with a small 

 amount of helixin 1). The aciueous layer remaining 

 is extracted with n-butanol. Concentration of this 

 extract to dryness gives helixin A. Helixin B is 

 further purified l)y partition chromatography (3). 



Chemical and physical properties: Helixin coni- 

 plcx: Contains four components. A, B, C, and D, 

 having approximate Rf values of 0.07, 0.42, 0.85, 

 and 0.68, respectively (butanol-ethyl acetate, 

 1:1) (3). Solul)le in ethanol, methanol, pyridine, 

 and glacial acetic acid. Slighth- soluble in n-buta- 

 nol, acetone, and chloroform. Insoluble in ether, 

 petroleum ether, benzene, ethyl acetate, and car- 

 bon tetrachloride. Negative Molisch, ninhydrin, 

 Hopkins-Cole, xantho})roteic, Millon, and FeCl.3 

 tests. More stable at alkaline pH; somewhat less 

 stable than endomycin (1). Most active at alkaline 

 pH (2). May have one or more components in 

 common with endomycin (3). 



Biological actii^y: Active against yeasts and 

 fungi at 15 /ug per ml or less. Active on bacteria at 

 >30 Mg per ml (1). Control of Helminthosporium 

 vicioriae blight of oats and H. sativum seeding 

 blight of barley with seed treatment (greenhouse 

 tests). In the field, seed treatment with helixin B 

 controls wheat bunt, oat smut, and covered smut 

 of barley (4). Protective action against tomato 

 early blight (Alternaria solani) (2). 



