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PubMedDate not supplied

Selective enrichment and characterization of Roseospirillum parvum, gen. nov. and sp. nov., a new purple nonsulfur bacterium with unusual light absorption properties.

A new type of phototrophic purple bacterium, strain 930I, was isolated from a microbial mat covering intertidal sandy sediments of Great Sippewissett Salt Marsh (Woods Hole, Mass., USA). The bacterium could only be enriched at a wavelength of 932 (+/- 10) nm. Cells were vibrioid- to spirilloid-shaped and motile by means of bipolar monotrichous flagellation. The intracytoplasmic membranes were of the lamellar type. Photosynthetic pigments comprised bacteriochlorophyll a and the carotenoids spirilloxanthin and lycopenal. The isolated strain exhibited an unusual, long-wavelength absorption maximum at 911 nm. Sulfide or thiosulfate served as electron donor for anoxygenic phototrophic growth. During growth on sulfide, elemental sulfur globules formed outside the cells. Elemental sulfur could not be further oxidized to sulfate. In the presence of sulfide plus bicarbonate, fructose, acetate, propionate, butyrate, valerate, 2-oxoglutarate, pyruvate, lactate, malate, succinate, fumarate, malonate, casamino acids, yeast extract, L(+)-alanine, and L(+)-glutamate were assimilated. Sulfide, thiosulfate, or elemental sulfur served as a reduced sulfur source for photosynthetic growth. Maximum growth rates were obtained at pH 7.9, 30 degrees C, 50 micromol quanta m-2 s-1 of daylight fluorescent tubes, and a salinity of 1-2% NaCl. The strain grew microaerophilically in the dark at a partial pressure of 1 kPa O2. The DNA base composition was 71.2 mol% G + C. Sequence comparison of 16S rRNA genes indicated that the isolate is a member of the alpha-Proteobacteria and is most closely related to Rhodobium orientis at a similarity level of 93.5%. Because of the large phylogenetic distance to known phototrophic species of the alpha-Proteobacteria and of its unique absorption spectrum, strain 930I is described as a new genus and species, Roseospirillum parvum gen. nov. and sp. nov.

Bacteria↗
PubMed1976

Massive excretion of 2-oxoglutaric acid and 3-hydroxyisovaleric acid in a patient with a deficiency of 3-methylcrotonyl-CoA carboxylase.

A three-month old child, presenting with a history of feeding problems, suspected respiratory infection and failure to thrive, later developed fits and a profound irreversible metabolic acidosis. Chromatographic investigation of the urine revealed a gross excretion of 2-oxoglutaric and 3-hydroxyisovaleric acids. The identity of these two acids was confirmed by mass spectrometry. Enzyme studies on liver obtained at post-mortem demonstrated a deficiency of 3-methylcrotonyl-CoA:carbon dioxide ligase (ADP) (EC 6.4.1.4).

Crotonates↗
PubMed1986

Gemfibrozil increases both apo A-I and apo E concentrations. Comparison to other lipid regulators in cholesterol-fed rats.

HDL cholesterol (HDL-C) was increased by gemfibrozil (+3.6-fold), fenofibrate (+1.3-fold) and ciprofibrate (+1.2-fold) but not clofibrate or bezafibrate when dosed PO at 50 mg/kg for 2 weeks in cholesterol-fed rats. Cholesterol in apo B-containing lipoproteins decreased with gemfibrozil (-76%), clofibrate (-12%) and ciprofibrate (-12%). Plasma apo B decreased to the greatest extent with gemfibrozil (-86%) followed by ciprofibrate (-47%), fenofibrate (-40%), clofibrate (-24%) and bezafibrate (-20%). Only gemfibrozil increased plasma apo E levels which are characteristically low in this rat model. Gemfibrozil, fenofibrate and ciprofibrate increased apo A-I concentrations. It is concluded that plasma lipid regulators which elevate HDL in this model might do so by altering the metabolism and hence plasma concentration of apoAI (fenofibrate, ciprofibrate) or both apo E and A-I (gemfibrozil). It is hypothesized that drugs which alter the metabolism of both HDL peptides result in the greatest HDL-C elevation in the rat.

Animals↗
PubMed1988

19F nuclear magnetic resonance spectroscopy study of the complex of 2-benzyl-4-oxo-5,5,5-trifluoropentanoic acid and carboxypeptidase A.

(dl)-2-Benzyl-4-oxo-5,5,5-trifluoropentanoic acid is a strong transition state analog inhibitor of the zinc protease carboxypeptidase A. 19F NMR spectroscopy of the aqueous solution of this inhibitor shows the hydrate of the ketone carbonyl to be the major species, with a shift of -9.95 ppm. As the pH is varied from 4.9 to 13.1, a 1.53 ppm downfield shift occurs, giving a pK alpha of 11.10. When excess inhibitor is added to the enzyme, a new, bound peak appears at -8.84 ppm, in addition to the free hydrate peak. Spectra taken at pH's from 4.90 to 9.15 show no change in the position of the bound resonance; from 9.15 to 12.15, a 0.26 ppm upfield shift occurs. The interpretation is that the monoanion of the hydrate is the form that binds to the enzyme.

Carboxypeptidases↗
PubMed1976

Properties of the testicular lactate dehydrogenase isoenzyme.

1. Studies were carried out with pure lactate dehydrogenase isoenzymes C4 (LDH isoenzyme X), B4, (LDH isoenzyme 1) and A4 (LDH isoenzyme 5) isolated from mouse testis, heart and muscle tissue respectively; with LDH isoenzyme X purified from pigeon testes and with crude lysates of spermatozoa from man, bull and rabbit. 2. LDH isoenzyme X from all species showed greater ability than the other isoenzymes to catalyse the NAD+-linked interconversions of 2-oxobutanoate into 2-hydroxybutanoate and of 2-oxopentanoate into 2-hydroxypentanoate. 3. Mouse LDH isoenzyme X presented the broadest spectrum of substrate specificity. It exhibited very similar Km values for a variety of 2-oxo acids: 2-oxopropanoate (pyruvate), 2-oxobutanoate, 2-oxo-3-methylbutanoate, 2-oxopentanoate, 2-oxo-3-methylpentanoate, 2-oxo-4-methylpentanoate, 2-oxohexanoate and 2-oxo-3-phenylpropanoate (phenylpyruvate). The corresponding 2-hydroxy acids were also readily utilized in the reverse reaction. A strong inhibition by substrate and product was demonstrated for the direct reaction. 4. Intracellular distribution of LDH isoenzyme X was investigated in mouse testes. LDH isoenzyme X activity was located in the fraction of "heavy mitochondria" and in the soluble phase. 5. A possible functional role for LDH isoenzyme X is proposed: the redox couple-2-oxo acid-2-hydroxy acid could integrate a shuttle system transferring reducing equivalents from cytoplasm to mitochondria.

Animals↗