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Two new compounds, 8'-phospho derivatives of amicoumacins A and B, were isolated from the culture broth of a strain of Bacillus pumilus together with amicoumacins A and B. Their structures were elucidated on the basis of spectroscopic methods and alkaline phosphatase treatments. Comparison of the antibacterial activities against methicillin-resistant Staphylococcus aureus (MRSA) of these compounds suggested that C-8' hydroxyl and C-12' amide group of amicoumacin A played a critical role for anti-MRSA activity.

5beta-Methoxy (20), 14-methyl (24), 14,14-dibromo-15-nor (25), 8-O-acyl (26-45), 8-O-alkyl (46), 8-O-alkoxycarbonyl (47, 48), and 8-O-carbamoyl (49) derivatives of PA-48153C, a novel immunosuppressant isolated from fermentation products of Streptomyces prunicolor PA-48153, were prepared. These compounds were found to retain the inhibitory activity on the responses of both T and B cells to mitogens. Among them, the C-8 hexanoate 28 showed potent suppressive effects on mitogen responses with less cytotoxicity to EL4 cells and was selected for in vivo evaluation.

A newly isolated bacterium which produces antibacterial substances as below was taxonomically characterized and identified with Corynebacterium equi. The major antibiotic produced was determined to be hygromycin by direct comparison. The minor component, newly named epihygromycin was proved to be an epimer of hygromycin by spectrosocopic evidences and by chemical conversions. The presence of epihygromycin in the metabolites of Streptomyces noboritoensis (reported to be a hygromycin producer) was also observed.

A new peptide antibiotic complex, named octapeptin D, was isolated from culture broth of a microorganism belonging to the genus Bacillus. The trihydrochloride of the antibiotic was obtained as a colorless powder, soluble in water and methanol. The empirical formula, C47H88N12O11.3HCl.H2O, was indicated by elemental analysis. Amino acid analysis on the acid hydrolyzate demonstrated the presence of 2,4-diaminobutyric acid (4 moles), serine (1 mole) and leucine (3 moles). Gas chromatographic analysis with the methylated product of the ethereal extract of the acid hydrolyzate revealed the presence of beta-hydroxy isodecanoic acid, beta-hydroxy decanoic acid, beta-hydroxy isoundecanoic acid and beta-hydroxyanteisoundecanoic acid. Octapeptin D is active against Gram-negative and Gram-positive bacteria in vitro and in vivo.

A new antibiotic TL-119 active against gram-positive bacteria was isolated from a strain resembling Bacillus subtilis. The antibiotic is a neutral substance, soluble in a mixture of chloroform and methanol, and is a peptide with an empirical formula of C42H57N7O9, containing threonine (1), alanine (1), valine (1), leucine (1) and phenylalanine (2).

A selective isolation medium was devised for Pseudomonas bacteria. An antibiotic mixture which contained 10 micrograms per ml of cerexin A, 10 micrograms per ml of nalidixic acid and 30 micrograms per ml of cycloheximide was used. With the antibiotic medium, 58 strains of bacteria presumed to be Pseudomonas which were subdivided into 18 taxonomically different groups were isolated from 3 soil samples with 9% of contaminants. With this method, it was possible to isolate a Pseudomonas bacterium from a sample containing about 400 times as many other Gram-positive and -negative bacteria.

A new antibiotic named 61-26 active against gram-positive bacteria and some fungi was isolated from a Bacillus strain. The antibiotic is a weakly basic peptide slightly soluble in aqueous alcohols. An approximate empirical formula of C50H93N11O17 and constituent amino acids of aspartic acid (1 mole), serine(2 moles), alanine (2moles), and sum of valine and isoleucine (2 moles) are indicated.

A selective medium containing 25 to 50 micrograms per ml of tunicamycin was devised to isolate micromonosporae from soil samples, making possible simple, preferential isolation of a variety of Micromonospora. When a large amount of Gram-negative bacteria was present in a sample, alkaline treatment (0.01 N NaOH, 5 approximately 10 minutes at 15 degrees C) wa employed to reduce the numbers. Using the tunicamycin agar medium, 1,585 strains of presumably different micromonosporae were obtained from 400 soil samples collected from various regions around the world. In average, 4 different Micromonospora strains could be located from one soil sample. This tunicamycin method made possible a concentrated screening method for new antibiotics from Micromonospora.

Two water-soluble basic antibiotics named galantins I and II were isolated from a strain resembling Bacillus pulvifaciens. Both antibiotics are peptides containing glycine, alanine, ornithine, lysine and some unknown ninhydrin-positive components. An approximate empirical formula C50 plus and minus H98plus and minus 2O17N16 is indicated for galantin I. These are active against some gram-positive, acid-fast and gram-negative bacteria.

Two new members of polymyxin group antibiotics, polymyxins S1 and T1, were isolated from the culture broths of strains identified as Bacillus polymyxa Rs-6 and Bacillus polymyxa E-12, respectively. These antibiotics are strongly basic substances, their hydrochloric acid salts are soluble in water and methanol. They are primarily active against Gram-negative bacteria in vitro and in vivo though polymyxin T1 exhibits higher activities against Gram-positive bacteria than other polymyxin group antibiotics.

A new antibiotic, trichostatin, was isolated from the metabolites of strains of Streptomyces hygroscopicus. It is active against trichophytons and some fungi. The structure was determined to be a derivative of a primary hydroxamic acid by chemical and spectroscopic evidences.

A new antibiotic named 339-29, active against Gram-positive bacteria was isolated from a strain of Bacillys pumilus. The hydrochloride is soluble in water and aqueous alcohols. The antibiotic is a basic peptide containing valine (3), isoleucine (1), Leucine (2), tyrosine (1), lysine (3) and a fatty acid.

In general, spores of B. cereus, B. megaterium, B. Sphaericus and B. subtilis strains germinated uniformly within a short time of incubation in a germination medium. In contrast, spores of B, circulans, B. brevis, B. laterosporus, B. pulvifaciens, B. polymyxa, B. pumilus, B. licheniformis and B. coagulans strains were usually slow and/or uneven germinators under the same conditions of incubation. The former group of Bacillus strains occur frequently in soils as the predominant population and the latter group of Bacillus species are found in many cases as minor populations. The minor populations of Bacillus were isolated with difficulty by the standard dilution-plate technique, but could easily be enriched by treating the soil sample in a germination medium for 2 to 3 hours at 30 to 35 degrees C, followed by heating it at 65 degrees C for 10 minutes ("minor-shifted isolation"). Using this technique, the minor Bacillus strains could be isolated from samples containing 100- to 1,000-fold more of the rapid germinators of Bacillus.

A new peptide antibiotic, brevistin, was isolated from the culture broth of Bacillus brevis 342-14. Brevistin is an acylpeptide with an approximate empirical formula of C63H91N15O18 containing aspartic acid, threonine, glycine, valine, isoleucine, phenylalanine, tryptophan and 2,4-diaminobutyric acid. The antibiotic is soluble in acid and alkaline water. Its hydrochloride is soluble in methanol. Brevistin is active against Ggam-positive bacteria in vitro and in vivo, and is of low toxicity to mice.

Thiocillins I and II were isolated from the culture broth of Bacillus cereus G-15, and thiocillins II and III from that of Bacillus badius AR-91. Also, the former two were probably produced by Bacillus megatherium I-13. These antibiotics active against Gram-positive bacteria are soluble in a mixture of chloroform and methanol, show characteristic ultraviolet absorptions (maxima at ca. 275 nm and ca. 348 nm), and contain a high content of sulfur, as much as approximately 15%. They are related to each other and also to micrococcin P, but differentiated by chromatographic behaviours.

A new antibiotic, 333-25, active against Gram-positive and Gram-negative bacteria, was isolated from the culture broth of Bacillus circulans 333-25. The antibiotic is a basic acylpeptide containing 2,4-diaminobutyric acid (5), leucine (2), phenylalanine (1) and a fatty acid. It is closely related to antibiotic EM 49, but can be differentiated by chromatographic behaviour.

Two new antibiotics cerexins A and B were isolated from different strains identified with Bacillus cereus. These two antibiotics are amphoteric in nature, soluble in particular solvents such as dimethylsulfoxide, dimethylformamide and alkaline water, and show typical infrared absorptions of peptide. These also have similar antimicrobial properties active against gram-postive bacteria.

A new biologically active substance, M-9337, was obtained from Streptomyces strain M-9337, a soil isolate. The producing organism was subsequently determined to be a new strain and named Streptomyces antihaemolyticus M-9337. The active substance was prepared as white yellow powder from culture broth by solvent extraction and silica gel thin-layer chromatography. It showed no antimicrobial activity and potent inhibitory activity against streptolysin, a type of hemolysin.

A new antibiotic, named laterosporamine, was isolated from the culture broth of Bacillus laterosporus 340-19. The antibiotic is active against Gram-positive and Gram-negative bacteria in vitro and in vivo. It is a water-soluble basic substance, positive to ninhydrin, SAKAGUCHI'S and DRAGENDORFF'S reagents. A non-peptidic structure with an approximate empirical formula C17H35N7O4 was suggested.

A preferential isolation procedure was devised for asporogenous (Asp), Gram-positive (Gp), aerobic or facultative anaerobic bacteria which included the genera Arthrobacter, Corynebacterium, Brevibacterium, Microbacterium, Mycobacterium, and Micrococcus (Asp-Gp bacteria). An antibiotics-mixture agar which contained 5 to 10 micrograms per ml of colistin, 10 to 20 micrograms per ml of nalidixic acid and 30 micrograms per ml of cycloheximide was used in the isolation. Using this technique 47 Asp-Gp bacteria representing 26 subgroups of coryneform bacteria and Micrococcus were isolated from 3 soil samples. The method was far more efficient than the standard dilution-plate technique. This preferential method is available to isolate Asp-Gp bacteria from a sample containing about 500-fold more of other Gram-positive and negative bacteria.