A new antibacterial agent, lysobactin, has been isolated from a species of Lysobacter (ATCC 53042). The antibiotic was recovered from the Lysobacter cell mass by extraction and reversed phase chromatography. Lysobactin is a dibasic peptide with marked activity against Gram-positive aerobic and anaerobic bacteria.

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Lysobactin, an antibiotic isolated from a strain of Lysobacter, is 2 to 4-fold more active than vancomycin against aerobic and anaerobic Gram-positive bacteria. Included in the spectrum of lysobactin are Staphylococci, Streptococci, corynebacteria, clostridia and various other Gram-positive anaerobic bacteria. The activity of lysobactin against aerobic and anaerobic Gram-negative bacteria is poor. When given parenterally the compound was efficacious in systemic staphylococcal and streptococcal infections in mice. Similarly, when applied topically lysobactin was also curative in a staphylococcal wound infection in mice. Some studies on the mode of action of lysobactin are presented.

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Pilatin, a new marasmane derivative, was isolated from fermentations of the cyphelloid fungus Flagelloscypha pilatii. Its structure was determined by chemical and physical methods. Pilatin inhibits the growth of bacteria and fungi at concentrations of 5-50μg/ml. The compound is highly cytotoxic. The incorporation of thymidine and uridine into DNA and RNA in Ehrlich carcinoma ascitic cells is strongly inhibited by pilatin. Like marasmic acid pilatin causes frameshift mutations in Salmonella typhimurium TA 98.

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Taxonomic studies on a new species, Kitasatosporia cystarginea are presented. Among the several species already described in this genus, this strain is characteristic in forming distinct spirals of spore chains. A significant properties of the species is the production of a new antifungal antibiotic, cystargin.

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A new sulfur-containing peptide antifungal antibiotic, cystargin, was isolated from the fermentation broth of a new species of genus Kitasatosporia, designated as Kitasatosporia cystarginea. On acid hydrolysis, cystargin (C₆₀H₇₇N₁₉O₁₇S₆) gave equimolar glycine, proline, aspartic acid and arginine. By performic acid oxidation, cysteic acid was detected after hydrolysis. It showed a growth inhibitory activity against various phytopathogenic fungi and inhibition of β-1, 3-glucan synthetase from Saccharomyces cerevisiae.

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Penidllium sp. FO-125, a soil isolate, was found to produce a new antifungal antibiotic complex named atpenin. Three components A4, A5 and B were isolated from the fermentation broth of the producing strain by solvent extraction, silica gel column chromatography and HPLC. The molecular formula of atpenins A4, A5 and B were determined to be C₁₅H₂₂NO₅Cl, C₁₅H₂₁NO₅Cl₂ and C₁₅H₂₃NO₅, respectively, on the basis of high resolution electron impact mass spectrometry and elemental analysis. They are active against filamentous fungi, especially, Trichophyton sp.

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L-657, 398 is a broad spectrum antifungal agent isolated from solid fermentation or from the mycelium of the liquid fermentation of Aspergillus ochraceus. Structurally, the compound is a novel pyrollidine related to anisomycin.

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A novel antibiotic, aranorosin, was isolated from the fermentation broth of a new fungal isolate identified as Pseudoarachniotus roseus. The antibiotic showed a wide spectrum of activity.

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Aranorosin, a new antifungal antibiotic, has been isolated from the culture filtrate and mycelium of a strain of Pseudoarachniotus roseus Kuehn. The antibiotic, C₂₃H₃₃NO₆, contains a novel l-oxaspiro[4, 5]decane ring system. The structure (I) has been elucidated on the basis of spectroscopic and chemical analysis.

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A series of 7β-[2-(hetero aromatic methoxyimino)-2-(2-aminothiazol-4-yl)acetamido]cephalosporins have been synthesized and bacteriologically evaluated. Several substances in this series showed exceptional in vitro activity, especially those with a five-membered hetero aromatic substituent moiety at the 7-position and a quaternary ammonium group as the 3-function of the cephem nucleus. The most active derivative, 7β-[2-(imidazol-4-ylmethoxyimino)-2-(2-aminothiazol-4-yl)acetamidol-3-(pyridiniomethyl)ceph-3-em-4-carboxylate(13a) was the most evenly balanced with respect to activity against Gram-positive and Gram-negative bacteria. Furthermore, 13 was stable to various types of β-lactamases and had high affinities for penicillin binding protein-3 and -IBs of both Escherichia coli and Pseudomonas aeruginosa.

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A variety of glidobactin analogs modified at the fatty acid, L-threonine and nucleus moieties of the molecule were synthesized and their structure-activity relationships examined. The antitumor and antifungal activity was greatly influenced by modification of the fatty acid glidobactin, with the dodecanoyl and tetradecanoyl analogs exhibiting better antitumor activity than the parent antibiotics. Replacement of the L-threonine with other amino acids greatly reduced the activity and reduction of the double bond of the nucleus completely eliminated the biological activity of glidobactin.

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A novel method for the synthesis of histargin and its analogs is described. It includes two kinds of N-alkylation reactions that prevent the formation of side products. The inhibition of enzymes by these compounds was also measured. Some of the compounds strongly inhibited carboxypeptidase B, carboxypeptidase A, carboxypeptidase N (kiniase I), and angiotensin converting enzyme.

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Virginiae butanolide C, [2-(1'-hydroxyhexyl)-3-(hydroxymethyl)butanolide (3)], is one of the inducers of virginiamycin production in Streptomyces virginiae. Various racemic analogues were synthesized, and their effectiveness in virginiamycin induction was studied. Among analogues having a series of C-2 side chains, those with 1'-hydroxyheptyl or 1'-hydroxyoctyl moiety were most effective with a minimum effective concentration of 0.8 ng/ml. At the same length of C-2 side chain, a 2, 3-cis analogue was 10-fold more active than a 2, 3-trans analogue, and the 2, 3-trans analogue was 10-fold more active than an analogue having a 1'-ketoalkyl moiety at C-2 (A-factor type analogue). Methoxylation or deletion of either ' one of the two hydroxy groups in virginiae butanolide C analogues caused a 100 to 1, 000-fold decrease in activity, thus indicating the importance of the two hydroxy groups in virginiamycin induction.

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We inactivated the bialaphos (BA) resistance gene (bar) of a BA producer, Streptomyces hygroscopicus, by the gene replacement technique. The resulting BA-sensitive mutant (Bar^-) was able to produce little BA but considerable amount of an intermediate demethylphosphinothricin (DMPT). The Bar^- mutant was still able to convert the N-acetyl derivative (AcDMPT) of DMPT to BA. Introduction of normal bar containing plasmid restored both BA resistance and BA biosynthesis to levels as high as the parental BA producer. By contrast, introducing a multi copy glutamine synthetase gene (glnA) into the Bar" mutant restored BA resistance but not BA production. Thus, the bar gene plays a crucial role in both self-defense and a step of BA biosynthesis in the BA-producing S. hygroscopicus.

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Liblomycin (NK313), a novel analog of bleomycin and peplomycin (PEP), produced acid soluble DNA, base propenals and nucleo bases from isolated DNA. This was similar to the action of PEP. However, the DNA cleavage activity of NK313 was l/2- 1/10 of that of PEP in the absence of reducing agents. In the presence of reducing agents such as 2-mercaptoethanol and ascorbic acid, the activity of NK313 was stimulated more strongly than PEP. NK313 was also different from PEP in the formation and decomposition of active intermediates. This result suggested that differences in DNA cleavage activity between NK313 and PEP may be due to the different properties of their active intermediates. NK313 released preferentially pyrimidine bases from DNA, and the molar ratio of the released pyrimidine bases to the total of the released bases was little affected by the concentration of NK313 relative to DNA. In contrast, the ratio of the released purine bases by PEP increased with the concentration of PEP relative to DNA. NK313 induced double strand cleavage on pBR322 DNA as efficiently as did PEP. The major cleavage sites of NK313 on pBR322 DNA were similar to those of PEP. However, certain minor cleavage sites of NK313 were specific for NK313. Increase of PEP concentration led to increased degradation of DNA fragments; this was not the case with NK313. These results indicate that the cleavage sites of NK313 were similar to, but more limited than those for PEP.

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The effect of a potent antitumor antibiotic, kazusamycin B, on the cell cycle of LI210 cells was examined. Kazusamycin B arrested synchronized LI210 cells at Gl phase. Retardation of metaphase initiation was also observed. Flow cytometric analysis of kazusamycin B-treated asynchronized cells also confirmed Gl arresting effect of kazusamycin B. In addition, an unidentified cell population with lower fluorescence intensity than Gl population was observed when the cells were exposed to the drug longer than 12 hours. Morphology of kazusamycin B-treated LI210 cells revealed that the intranuclear structure changed within 4 hours, and that abnormal condensation of nuclei coincided with the appearance of unidentified population. Kazusamycin B inhibited RNA synthesis moderately but specifically at 2 hours. However, this inhibition might be a secondary effect of the antibiotic-induced structural abnormality of the nuclei.

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The biological activity of the two main metabolites of ubenimex in humans, (-)-N[(2S, 3R)-3-amino-2-hydroxy-4-(4'-hydroxy)phenylbutyryl]-L-leucine (OH-ubenimex) and (2S, 3R)-3-amino-2-hydroxy-4-phenylbutyric acid (2S, 3R)-AHPA) was examined. OH-Ubenimex was almost identical in inhibitory activity against mouse peritoneal resident macrophage aminopeptidases (APases) and the growth of IMC carcinoma in mice to ubenimex. In contrast, the inhibition of; mouse spleen cell APase activities in vitro, blastogeneses of mouse T and B cells in vitro, delayed cutaneous hypersensitivity in mice, and the growth of C1498 leukemia and HeLa S₃ cells in vitro was weaker than ubenimex. Macrophage APase activity was only slightly inhibited by (2S, 3R)-AHPA which also had practically no activity in the other biological assays.

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A series of tremorgenic mycotoxins and related compounds were tested for oral toxicity to the fall armyworm (Spodoptera frugiperdd) and corn earworm (Heliothis zed) by incorporation of materials into artificial diets and examining mortality and weights after 7 days. Significant mortality to both insect species was caused with dihydroxyaflavinine and roseotoxin B, while significant mortality to H. zea was also caused by penitrem A at 25 ppm. After 7 days, weights of larvae treated with 25 ppm penitrem A, roseotoxin B, and verruculogen were less than 50% of controls for both insect species. Weights of H. zea larvae treated with 25 ppb of penitrem A were less than 50% those of control larvae. Relative toxicities of the tremorgens and related compounds to insects compared to vertebrates are discussed.

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FK482 is a new orally active cephem antibiotic which offers some advantages over the commercially available oral β-lactam antibiotics. It displayed a broad spectrum of activity in vitro against stock strains of Gram-positive and Gram-negative aerobes and anaerobes. FK482 was more active in vitro than cefixime (CFIX), cefaclor (CCL) or cephalexin (CEX) against clinical isolates of Gram-positive organisms such as methicillin-sensitive Staphylococcus aureus, coagulase-negative Staphylococci including Staphylococcus epidermidis and strains of the Streptococcus group. Moderate activity was found against methicillin-resistant S. aureus and Enterocoecus faecalis. Against clinical isolates of many Gram-negative species, including opportunistic pathogens, FK482 had good in vitro activity similar or slightly inferior to that of CFIX but superior to that of CCL or CEX. However, it was clearly inferior to CFIX in activity against Serratia marcescens, and was inactive against Pseudomonas aeruginosa. Strains of S. aureus resistant to methicillin were moderately susceptible to FK482. All tested strains of Klebsiella pneumoniae resistant to CCL and CEX were susceptible to FK482, as were all the strains of Escherichia coli, Proteus mirabilis, Haemophilus influenzae and Branhamella catarrhalis resistant to amoxicillin (AMPC). FK482, like CFIX, was relatively stable to all type of β-lactamases except Bacteroides fragilis and its stability was superior to that of CCL or CEX. The antibacterial activity of FK482 against CSH2 strains containing ampicillin-resistance plasmids was not affected by the presence of the ampicillin resistance determinants. FK482 showed higher affinity for the penicillin-binding proteins (PBPs) (3, 2 and 1) of S. aureus than did CFIX, CCL and CEX. FK482 also showed very high affinity for the PBPs (2 and 3) of E. faecalis and PBPs (3, la, 4, 2 and Ibs) of E. coli. The bactericidal activity of FK482 against S. aureus was almost as strong as that of AMPC and superior to that of CCL or CEX. Against Gram-negative bacteria such as E. coli, K. pneumoniae and P. mirabilis, FK482 was similar to CFIX and superior to CCL and CEX in bactericidal activity.

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The therapeutic activities of orally administered FK482 were compared with those of reference antibiotics against systemic and local infections with a variety of bacteria in mice and rabbits. In systemic infections in mice, oral FK482 was almost as effective as oral cefaclor (CCL) and more effective than oral cephalexin (CEX) against Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae and Proteus mirabilis infections. However, FK482 afforded superior protective activity when given subcutaneously against E. coli infection in mice, and this activity was more potent than that of subcutaneously given CCL. In comparison with CCL, the reason that the in vivo activity of orally given FK482 against mouse systemic infections was weaker than had been anticipated from its potent in vitro activity was due to its poor oral absorption in mice. In local infections in rabbits, a species in which FK482 was better absorbed than in mice, FK482 was more effective than CCL, CEX or amoxicillin (AMPC). Against pneumonia induced by S. aureus or Streptococcus pyogenes, FK482 was as effective as AMPC and more effective than CCL in reducing the number of viable bacteria in the lungs of infected rabbits. In the oral treatment of experimental ascending pyelonephritis in rabbits, FK482 was superior to CCL and AMPC against methicillinresistant S. aureus infection, as effective as AMPC and more effective than CCL against Enterococcus faecalis infection, and as effective as cefixime (CFIX) and more effective than CCL and AMPC against E. coli infection in reducing the number of viable bacteria in the kidneys and urine.

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The pharmacokinetic profile of FK482 was studied in mice, rats, rabbits and dogs after oral dosing and compared with that of cefixime, cefaclor and cephalexin. Considerable differences in oral absorption of FK482 were observed among the animal species. Absolute bioavailabilities of FK482 were 12.6% in mice, 15.3% in rats, 32.3% in rabbits and 72.3% in dogs. In mice and rats, the absorption of FK482 was poor, and was the lowest of the reference antibiotics. FK482 was moderately well absorbed, with higher plasma levels than cefixime in rabbits and, like cefixime, gave higher plasma levels and a longer half-life than cefaclor or cephalexin in dogs. The increase in the area under the serum concentration time curve (AUC) of FK482 was strictly proportional to the increase in dose in the range of 2.5 to 40 mg/kg in rats and dogs, and 2.5 to 20 mg/kg in rabbits and the urinary recovery rates were almost constant. All tissue concentrations of FK482 in rats and rabbits were lower than those of the reference antibiotics and reflected its lower plasma concentrations in these animals. The urinary recovery rates of FK482 were 9.8% for mice, 15.5% for rats, 45.8% for rabbits and 47.1% for dogs. The biliary recovery rate of FK482 was low; 1.4% in rats and less than 0.1% in rabbits and dogs. No active metabolites were detected in the plasma, urine or bile samples from rats, rabbits or dogs. FK482 was mainly absorbed in the jejunum, and was inactivated in the large intestine. The serum-protein binding of FK482 was almost the same as that of cefixime: 60-77% for mouse, rabbit and human serum, and 90-93% for rat and dog serum.

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