New antibiotic pumilacidins A, B, C, D, E, F and G were isolated from the culture broth of a strain of Bacillus pumilus. They are cyclic acylheptapeptide composed of a beta-hydroxy fatty acid, two L-leucine, two D-leucine, L-glutamic acid, L-aspartic acid and L-isoleucine (or L-valine). Pumilacidin components were inhibitory to herpes simplex virus type 1 and H+, K(+)-ATPase and demonstrated an...

Four depsipeptides (peptide lactones), called cyanopeptolins A, B, C and D, have been isolated from the cyanobacterium Microcystis sp. PCC 7806. They possess identical structures consisting of cyclic L-glutamic acid-gamma-aldehyde, L-leucine, N-methyl-phenylalanine, L-valine, L-threonine, L-aspartic acid, hexanoic acid and a variable basic amino acid. This variable amino acid can be L-arginine ...

The influence of the relative concentrations of amino acids in culture media on the growth of microorganisms was first brought to the attention of microbiologists by Gladstone (1939). He observed that isoleucine, valine, or leucine added singly to a synthetic medium inhibited the growth of the anthrax bacillus whereas a mixture of the three stimulated growth. Although Gladstone was unable at th...

FIG. 1. Diauxic lag of cuiltures conitaining valine and isoleucine. All cultures were grown by shakinig (330 rev/ min) at 37 C in medium containing 2.0 g ofNaH2PO4 O H20, 7.0 g ofK2HP04, 2.0 g of (NH4)2SO4, 0.2 g of MgSO4 v 7H20 and I mg of thiamine hydrochloride in I liter of distilled water. Overnight cultures grown in 0.2%o glucose were harvested by centrifugation during exponential phase, r...

The structures of propioxatins A (C17H29N3O6) and B (C18H31N3O6), new enkephalinase B inhibitors produced by Kitasatosporia setae SANK 60684, were determined. Both propioxatins consist of N-acyl-L-prolyl-L-valine. N-Acyl moieties of propioxatins A and B were alpha-propyl and alpha-isobutyl succinic acid beta-hydroxamic acid, respectively.

It is now believed that the amino groups of isoleucine and valine are accepted by their respective carbon chains during biosynthesis via a transamination. Most of the evidence for this hypothesis has been derived from experiments on isoleucineless and valineless mutants of Escherichia coli and Neurospora crassu (l-4). It is not positively established whether this transamination step can be medi...

Human ectocervical explant cultures were grown in medium with D-valine substituted for L-valine. Pure epithelial cell monolayers were obtained with both dialyzed and undialyzed fetal calf serum. Epithelial cell explant colonies grown in D-valine medium supplemented with undialyzed serum could routinely be subcultured if plated at a density of 1.5 x 10(4) cells/sq cm or higher. Such cultures cou...

The biosynthesis of isopenicillin N from delta-(L-alpha-aminoadipyl)-L-cysteinyl-D-valine in a cell-free system has been correlated wih O2 consumption by two methods, involving the use of an oxygen-electrode and an n.m.r. spectrometer respectively. The results are consistent with a 1 : 1 stoichiometric ratio for the dioxygen consumed to the isopenicillin N formed.