6-Hydroxydopamine: evidence for superoxide radical as an oxidative intermediate.

Superoxide dismutase inhibited the autoxidation of 6-hydroxydopamine as measured by the rate of formation of a quinone and the rate of oxygen consumption. These observations demonstrate the formation of the superoxide radical during the autoxidation process. This finding may be relevant to the mechanism of adrenergic nerve terminal degeneration caused by 6-hydroxydopamine.

Synthesis of plastoquinone-9 and phytylplastoquinone from homogentisate in lettuce chloroplasts.

Chloroform-soluble extracts of unpurified chloroplast preparations of lettuce, pea and spinach and of class I lettuce chloroplasts that have been incubated in the light with [methylene-3H]homogentisate contain 3H-labelled plastoquinones-9 and -8 (minor homologue), 2-demethyplastoquinones-9 and -8 (minor homologue), pytylplastoquinone and 2-demethylphytylplastoquinone. The absence of demethylquinols, the presumed precursors of the dimethylquinones, from the extracts to the fact that no precautions were taken in the extraction procedure to present their oxidation to the corresponding quinones. In unpurified lettuce chloroplasts the synthesis of these compounds from [methylene-3H]homogentisate is Mg2+-dependent and it is stimulated by light. The addition of isopentenyl pyrophosphate to the incubation mixtures increases the amounts of both groups of quinones (polyprenyl quinones and phytyl quinones) synthesised in the light and the amounts of polyprenyl quinones synthesised in the dark. Replacement of isopentenyl pyrophosphate with a source of preformed polyprenyl pyrophosphates brings about a marked rise in the amounts of polyprenyl quinones synthesized. This rise in polyprenyl quinone synthesis is further increased if the chloroplasts are subjected to osmotic shock. The presence of S-adenosylmethionine increases the amounts of dimethylquinones synthesized at the expense of the demethylquinones. The implied precursor-product relationships between 2-demethylphytylplastoquinone (quinol?) and phytylplastoquinone and between the 2-demethylplastoquinones (quinols) and plastoquinones were verified in a pulse-labelling experiment. Confirmation that these quinones, or their corresponding quinols, are synthesized in the chloroplast is provided by the fact that they are made in class I lettuce chloroplasts. In none of the many incubations carried out in the course of the study were any [3H]tocopherols produced.

Tyrosinase-catalyzed oxidation of dopa and related catechol(amine)s: a kinetic electron spin resonance investigation using spin-stabilization and spin label oximetry.

The oxidation of four catechol(amine)s by tyrosinase has been studied by electron spin resonance and optical methods. Rates of oxygen consumption and of dopaquinone and dopachrome formation during the oxidation of dopa have been measured, and compared with rates of dopasemiquinone production measured using spin-stabilization procedures. In the presence of spin-stabilizing metal ions, production of semiquinone is approximately quantitative. Time-dependent ESR spectra obtained from dopa and dopamine show a slow regeneration of semiquinone, suggesting that a semiquinone precursor is slowly reformed. In contrast, time-dependent spectra for 4-methylcatechol and N-acetyldopamine show decay of the primary semiquinone together with buildup of a secondary semiquinone apparently derived from the corresponding 6-hydroxy-catechol(amine). Thus, catecholamines that give rise to a cyclizable quinone show a pattern of behavior that differs from those that produce a non-cyclizable quinone. These results are discussed in terms of their possible significance to melanogenesis and the toxicity of catechol(amine)s, which has been attributed to production of semiquinones and/or other oxygen radicals.

Potential oxidative pathways of brain catecholamines.

The possibility that catecholamines can be oxidized via aberrant pathways in vivo is open to question, but in vitro oxidation via aerobic manipulations is established. Assuming oxidation does occur, we have examined quantitatively the fast chemical reactions of the initial oxidation products, the o-quinones. The nature and rates of these reactions were studies under the conditions simulating closely those which presumably exist in mammalian brain. The results are in close accord with existing literature and especially support oxidation pathways recently reported in [3H]-norepinephrine binding to particulate cell fractions.

Monoclonal antibodies distinguish between the head portions of two myosin isozymes from chicken breast muscle.

Monoclonal antibodies against chicken breast myosin and its subfragment-1(S-1) were produced. One antibody, 2G41, reacted with S-1 containing a light chain 3 (LC3), but not with another S-1 containing a light chain 1 (LC1) or a mixture of the light chains. A structural difference can be assumed to exist between the head portions of the two myosin isozymes. Antigenicity of S-1 toward 2G41 could not be detected after tryptic digestion into three fragments of 50K, 27K, and 20K daltons. Another monoclonal antibody, M68, was obtained from mice immunized with myosin. M68 preferably recognized the heavy chain from S-1 containing LC3 rather than that from that containing LC1 or S-1. M68 reacted with the 27K fragment among the three.

New antitumor antibiotic, LL-C10037 alpha. Fermentation, isolation and structure determination.

A new antitumor antibiotic, LL-C10037 alpha was isolated from the fermentation filtrate of a Streptomyces by adsorption, partition and reverse phase column chromatography. Its chemical structure was determined by 1H NMR, 13C NMR, UV, IR and mass spectral data. LL-C10037 alpha is a gamma-aminoepoxysemiquinone and is related to the epoxyguinone class of antibiotics.

New antibiotics, enaminomycins A, B and C. I. Producing organism, fermentation and isolation.

New antibiotics, enaminomycins A, B and C, were found in the culture broth of streptomycete strain No. 13120, which was identified as Streptomyces baarnensis and designated as S. baarnensis No. 13120. Fermentation of enaminomycins were performed by conventional submerged culture in a 30-liter jar fermentor. Isolation of the antibiotics was performed by centrifugation of the culture broth and adsorption of the antibiotics from the supernatant on a column of activated carbon, followed by elution with aqueous acetone. Enaminomycins A, B and C were separated from each other on a column of Sephadex LH-20.

Dnacins, new antibiotics. I. Producing organism, fermentation, and antimicrobial activities.

Dnacins are new antibiotics produced by an actinomycete, strain No. C-14482 (N-1001). The characteristic features of the organism are: the formation of coremia on solid media, production of rod-shaped motile spores with peritrichous flagella from mature aerial mycella, fragmentation of the mature organism (at later stage of growth) in liquid media in which some fragmented elements have motility, lysozyme resistance, meso-diaminopimelic acid in the cell wall, and a guanine-cytosine content of 71 +/- 1 mol%. The organism has been designated as Nocardia sp. No. C-14482 (N-1001). Dnacins show strong activity against various GRam-negative, Gram-positive, and acid-fast bacteria, but slight activity against fungi. The antibiotics hardly affect the growth of Escherichia coli K-12 under anaerobic condition even at concentrations more than five times that of the minimum inhibitory concentrations under aerobic conditions.

Macbecins I and II, new antitumor antibiotics. II. Isolation and characterization.

New antitumor antibiotics, macbecins I and II, were isolated from the culture broth of Nocardia sp. No. C-14919. Macbecins I and II belong to the ansamycin group and have a benzoquinone and hydroquinone nucleus, respectively. Both showed antitumor activity against murine leukemia P 388 in vivo.

Nanomycins, new antibiotics produced by a strain of Streptomyces. II. Structure and biosynthesis.

Evidence is put forward which describes the structure and stereochemistry of new antibiotics, nanaomycins A and B, as I and V, respectively. In order to study biosynthesis and to determine the position of the hydroxyl group in the naphthoquinone moiety, a feeding experiment with 1-13C-acetate was effectively carried out. Nanaomycins A and B were found to be synthesized from acetate via a polyketide by Streptomyces rosa var. notoensis.

Herbimycin B, a new benzoquinonoid ansamycin with anti-TMV and herbicidal activities.

A new benzoquinonoid ansamycin, herbimycin B was isolated from the culture broth of Streptomyces hygroscopicus No. AM-3672, a herbimycin A-producing strain. Herbimycin B showed potent anti-TMV activity. Herbicidal effect of herbimycin B was less than that of herbimycin A.

Cyanocycline A, a new antibiotic. Taxonomy of the producing organism, fermentation, isolation and characterization.

A new antibiotic, cyanocycline A, was isolated from the fermentation broth of Streptomyces flavogriseus strain No. 49, a soil isolate. The molecular formula of cyanocycline A was determined to be C22H26N4O5. The antibiotic has a cyano group and a N-heterocyclic quinone moiety in its structure. Cyanocycline A was found to have broad spectrum antimicrobial and antitumor activity.

Macbecins I and II, new antitumor antibiotics. I. Producing organism, fermentation and antimicrobial activities.

New antibiotics, macbecins I and II, have been found in the culture fluid of an actinomycete, which has the following properties: delayed fragmentation of vegetative mycelia, formation of coremia on solid media, the occurrence of meso-diaminopimelic acid in the cell wall, lysozyme resistance, and guanine-cytosine content of 71 +/- 1 mol%. The organism has been designated Nocardia sp. No. C-14919 (N-2001). A marked enhancement of the production of macbecins I and II was observed in cultures containing L-tyrosine. The antibiotics are moderately active against several Gram-positive bacteria and fungi. The antibiotics also inhibit the growth of Tetrahymena pyriformis W at 2 microgram/ml but show no activity against the regeneration of cilia in partially deciliated Tetrahymena at 10 microgram/ml.

Studies on terreic acid.

It was found that Aspergillus sp. No. Y-8980 which was isolated from a soil sample collected at Yoron Island in Kagoshima Prefecture belonged to Aspergillus terreus group by morphological observation. The active substance produced by the strain was obtained with a high yield in sucrose-yeast extract medium and extracted by chloroform, ethyl acetate and n-butanol at pH 2.4 approximately 2.6 from the culture broth. The substance was crystallized from chloroform and ethyl acetate after charcoal treatment of the crude crystal. From various physico-chemical properties, it was found that the substance was identical to terreic acid. Terreic acid showed MICs of 25 approximately 100 mcg/ml, 12.5 mcg/ml and 50 mcg/ml against Gram-positive and Gram-negative bacteria, Xanthomonas oryzae and Xanthomonas citri, respectively, but it did not control Pseudomonas, fungi and yeast. The LD50 was 75 mg/kg i.p. and i.v. in mice. With regards to the anti-tumor effect, the morphological degeneration on HeLa cells (human carcinoma cells) was observed in the concentrations of more than 6.25 mcg/ml of terreic acid. An increase of body weight of mice caused by Ehrlich ascites carcinoma cells was not definitely observed by the daily administration of 150 mcg of terreic acid per mouse for 8 consecutive days. Above showed the enough survival effect in dd mice implanted with Ehrlich ascites carcinoma cells, and the effect also was demonstrated by anatomies of mice.