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PubMed1981

Inhibition of carotenoid synthesis in Micrococcus roseus.

Micrococcus roseus forms bicyclic keto-carotenoids. The effects of nicotine, piperonyl butoxide, and 2-(4-chlorophenylthio)-triethylamine hydrochloride (CPTA) were studied with regard to their ability to selectively inhibit carotenogenesis in the organism. Nicotine caused accumulation of beta-zeacarotene; piperonyl butoxide caused accumulation of phytoene and traces of phytofluene, zeta-carotene, and beta-zeacarotene. In both cases canthaxanthin biosynthesis was inhibited. CPTA inhibited canthaxanthin synthesis and caused accumulation of beta-zeacarotene and gamma-carotene and their mono- and di-hydroxy derivatives. Regardless of the inhibitor used, canthaxanthin was the major colored carotenoid biosynthesized. The expected precursors of carotenoid cyclization, neurosporene and (or) lycopene, were not detected in CPTA- or nicotine-inhibited cultures. Therefore, carotenoid cyclization in M. roseus does not involve neurosporene or lycopene and must occur early in carotene biosynthesis, prior to the formation of beta-zeacarotene, zeta-Carotene is proposed as the cyclization substrate and beta-zeacarotene as the substrate for oxygen insertion.

Carotenoids↗
PubMed1975

Membrane protein synthesis in Micrococcus lysodeikticus and selective effect of chloramphenicol.

Micrococcus lysodeikticus cytoplasmic membranes labeled with ]-14C]arginine plus [-14C]-threonine were prepared and subjected to mild washing treatments to fractionate membrane proteins. Polyacrylamide gel electrophoresis of total membranes, in the presence of sodium dodecyl sulfate, results in the separation of 28-30 bands of labeled protein. Three peaks of protein show higher specific radioactivity than the others. Chloramphenicol at 100 mug/ml inhibits the incorporation of labeled precursors into membrane proteins by 45-70 percent, some of them being more affected by the antibiotic. From all available results, we suggest that the partial inhibitory effect shown by this antibiotic could be due to the existence of specific biosynthetic sites for some membrane proteins, which are differently affected by chloramphenicol.

Arginine↗
PubMed1975

Inhibition of cardiolipin synthesis by end-products and other complex lipids in membrane preparations of Micrococcus lysodeikticus.

Using membrane preparations of Micrococcus lysodeikticus, the end-products of cardiolipin synthesis, cardiolipin and glycerol, were shown to inhibit cardiolipin synthetase at several concentrations. Other phospholipids tested for inhibitory effects, phosphatidyl-ethanolamine, phosphatidylinositol, and phosphatidic acid were also shown to inhibit cardiolipin synthesis. Phosphatidic acid was considerably more inhibitory than cardiolipin, phosphatidylethanolamine was similar to cardiolipin, and phosphatidylinositol less inhibitory at the same concentrations. A non-phosphate-containing glycolipid was also inhibitory. In contrast, glycerophosphate had no effect on cardiolipin synthesis.

Cardiolipins↗
PubMed1980

Passive diffusion of nucleosides into Micrococcus sodonensis membrane vesicles.

Nucleoside entry into isolated membrane vesicles of Micrococcus sodonensis (luteus) was studied using 14C-labelled nucleosides: adenosine, inosine, cytidine, uridine, guanosine, and thymidine. All nucleosides were recovered unmetabolized from the vesicles except adenosine and cytidine which were partly deaminated by membrane-bound enzymes. Vesicle preparations actively transported proline but no energy source was found capable of supporting concentrative nucleoside uptake. The entry of nucleosides into M. sodonensis vesicles was not saturable, nor was there competition between the nucleosides studied for entry. It was concluded that nucleoside entry into M. sodonensis vesicles occurs by passive diffusion.

Adenosine↗
PubMed1986

Discrepancy between the antibacterial activities and the inhibitory effects on Micrococcus luteus DNA gyrase of 13 quinolones.

Thirteen quinolone antibacterial agents were investigated as to their ability to inhibit Micrococcus luteus DNA gyrase and cell growth, and compared to those of novobiocin and coumermycin. Among the quinolones tested, the most active were found to be CI-934 and ciprofloxacin, which inhibited gyrase full supercoiling activity at concentrations of 100 and 200 micrograms/ml, respectively, while inhibiting cell growth at a concentration of 1 microgram/ml. However, both novobiocin and coumermycin inhibited gyrase full supercoiling activity at concentrations of 0.5 and 1.0 microgram/ml, respectively, which were comparable to those concentrations causing inhibition of cell growth.

Aminocoumarins↗
PubMed2002

Increased inflammation in lysozyme M-deficient mice in response to Micrococcus luteus and its peptidoglycan.

More than 70 years ago, Alexander Fleming discovered lysozyme and proposed that nonpathogenic bacteria fail to cause disease because they are very susceptible to destruction by lysozyme, an enzyme that is one of the principal proteins of phagocytes. Although much has been learned about the effects of lysozyme in vitro, its biological role in vivo has not been determined. We examined transgenic mice deficient in lysozyme M after challenge by the normally nonpathogenic and highly lysozyme-sensitive bacterium Micrococcus luteus. Despite partial compensation by newly expressed lysozyme P in macrophages, lysozyme M-deficient mice developed much more severe lesions than wild-type mice. The tissue injury was due to the failure of lysozyme M-deficient mice to inactivate peptidoglycan, resulting in an intense and prolonged inflammatory response. Our data indicate that tissue injury is normally limited by prompt degradation of bacterial macromolecules that trigger innate immunity and inflammation.

Animals↗
PubMed1999

Purification, properties and reactivity of the esterase from Micrococcus sp.

The esterase from Micrococcus sp., which hydrolyzes n-propyl-2-fluorocyclopropanecarboxylate (3) enantioselectively, was highly purified by three types of chromatography. The purified enzyme was inactivated by Hg and diisopropyl fluorophosphate (DFP). It was a monomer with a molecular weight of about 35000. The enzyme exhibits esterase activity towards many aliphatic propyl esters. The enantioselectivity for substrate (3) using purified enzyme did not differ from that of crude enzyme.

Esterases↗
PubMed1992

Colorimetric assay for lysozyme using Micrococcus luteus labeled with a blue dye, Remazol brilliant blue R, as a substrate.

Micrococcus luteus (M. lysodeikticus) labeled with Remazol brilliant blue R (blue ML) was prepared as a novel substrate for the colorimetric assay of lysozyme. The treatment of the labeled substrate with lysozyme resulted in the release of soluble blue products which can be easily measured spectrophotometrically at 600 nm. The blue color was most efficiently released at pH 7 and ionic strength of 0.2 on incubation with hen lysozyme at 40 degrees C. A new colorimetric method for the assay of lysozyme using this substrate was developed. The assay system gave a linear dose-response curve, and as little as 0.1 microgram of human lysozyme (1 microgram/ml, 100 microliters) can be detected. The present method is more convenient and reproducible than the conventional lysozyme assay with bacterial cells. Application of the system to the determination of lysozyme in human serum is described.

Adult↗
PubMed2001

Purification and characterization of an esterase from Micrococcus sp. YGJ1 hydrolyzing phthalate esters.

An esterase hydrolyzing phthalate esters has been purified from Micrococcus sp. YGJ1. The enzyme, a monomeric protein (Mr = 56 kDa) with a pI of 4.0, hydrolyzes various aliphatic and aromatic carboxylesters. The medium chain (C3-C4) esters are the most preferred substrates. The enzyme is inhibited by HgCl2 and p-chloromercuribenzoate but not by phenylmethylsulfonyl fluoride.

Dibutyl Phthalate↗
PubMed2003

Primary structure of inorganic polyphosphate/ATP-NAD kinase from Micrococcus flavus, and occurrence of substrate inorganic polyphosphate for the enzyme.

The gene encoding an inorganic polyphosphate/ATP-NAD kinase was cloned from Micrococcus flavus, and its primary structure was analyzed. Alignment of the primary structure with those of other characterized NAD kinases revealed candidate amino acid residues, mainly charged ones, that would be related to inorganic polyphosphate use. The alignment also showed that the primary structure found carried a protruding C-terminal polypeptide. Although the C-terminal polypeptide was demonstrated to be dispensable for the kinase activities, and was proposed to be removed in M. flavus, the entire primary structure including the C-terminal polypeptide was homologous with that of the ATP synthase beta chain. The inorganic polyphosphate used by the inorganic polyphosphate/ATP-NAD kinase as a phosphoryl donor was isolated from cells of M. flavus, suggesting that the ability of the enzyme to use inorganic polyphosphate is of physiological significance and is not an evolutionary trait alone.

Adenosine Triphosphate↗
PubMed2006

Partial purification of mannosylphosphorylundecaprenol synthase from Micrococcus luteus: a useful enzyme for the biosynthesis of a variety of mannosylphosphorylpolyisoprenol products.

Membrane fractions from Micrococcus luteus catalyze the transfer of mannose from GDP-mannose to mono- and dimannosyldiacylglycerol, mannosylphosphorylundecaprenol (Man-P-Undec), and a membrane-associated lipomannan. This chapter describes the detergent solubilization, partial purification, and properties of Man-P-Undec synthase. The mobility of the mannosyltransferase activity on sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicates that the enzyme is a polypeptide with a molecular weight of approx 30.7 kDa. Utilizing the broad specificity of the bacterial mannosyltransferase provides a useful approach for the enzymatic synthesis of a wide variety of Man-P-polyisoprenol products.

Chromatography, Agarose↗
PubMed2001

Cooperativity and substrate specificity of an alkaline amylase and neopullulanase complex of Micrococcus halobius OR-1.

The saccharifying alkaline amylase and neopullulanase complex of Micrococcus halobius OR-1 hydrolyzes both alpha-(1,4)- and alpha-(1,6)-glycosidic linkages of different linear and branched polysaccharides. The following observations were made concerning the analysis of the coexpressed amylase and neopullulanase enzymes. Even though the enzymes were subjected to a rigorous purification protocol, the activities could not be separated, because both the enzymes were found to migrate in a single peak. By contrast, two independent bands of amylolytic activity at 70 kDa and pullulanolytic activity at 53 kDa were evident by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), reducing and nonreducing PAGE, and zymographic analysis on different polysaccharides. Preferential chemical modification of the enzyme and concomitant high-performance thin-layer chromatographic analyses of the saccharides liberated showed that amylase is sensitive to 1-(dimethylamino-propyl)-3-ethyl carbodiimide-HCl and cleaved alpha-(1,4) linkages of starch, amylose, and amylopectin producing predominantly maltotriose. On the other hand, formalin-sensitive neopullulanase acts on both alpha-(1,4) and alpha-(1,6) linkages of pullulan and starch with maltotriose and panose as major products. It is understood that neopullulanase exhibits dual activity and acts in synergy with amylase toward the hydrolysis of alpha-(1,4) linkages, thereby increasing the overall reaction rate; however, such a synergism is not seen in zymograms, in which the enzymes are physically separated during electrophoresis. It is presumed that SDS-protein intercalation dissociated the enzyme complex, without altering the individual active site architecture, with only the synergism lost. The optimum temperature and pH of amylase and neopullulanase were 60 degreesC and 8.0, respectively. The enzymes were found stable in high alkaline pH for 24 h. Therefore, the saccharifying alkaline amylase and neopullulanase of M. halobius OR-1 evolved from tapioca cultivar shows a highly active and unique enzyme complex with several valuable biochemical features.

Amylases↗
PubMed1977

Purification and characterization of the DNA-dependent RNA polymerase and its subunit sigma from Micrococcus luteus.

DNA-dependent RNA polymerase from Micrococcus luteus can be isolated from cell extracts after removal of an excess of nucleic acids by fractionation with ammonium sulfate, followed by two consecutive gel filtrations through agarose and chromatography on cellulose phospate. Either homogeneous holoenzyme or a mixture of core and holoenzyme is obtained in this way, as is indicated by electrophoresis in polyacrylamide gels in the absence of detergent, where core enzyme migrates ahead of holoenzyme. Homogeneous core enzyme can be isolated from holoenzyme by chromatography on DEAE-cellulose. Core enzyme contains the subunits alpha, beta and beta' previously described [U.I. Lill et al., (1975) Eur. J. Biochem. 52, 411-420] in a molar ratio of 2:1:1. Holoenzyme contains an additional subunit sigma of 80 000 molecular weight (molar subunit composition alpha2 betabeta' sigma) and two relatively small polypeptides (molecular weight 14 000 and 25 000, respectively). Subunit sigma may be isolated from holoenzyme by chromatography on DEAE-cellulose at pH 6.9 in the presence of low concentrations of glycerol. The behaviour of holoenzyme during sedimentation in a glycerol gradient at low ionic strength indicates its occurrence as a dimer of the alpha2betabeta'sigma-protomer, whereas the monomeric form is preferred by core enzyme. Holoenzyme is much more active than core enzyme in RNA synthesis on bacteriophage T4DNA as template. The activity of the latter is stimulated by isolated sigma. M. luteus sigma as well as holoenzyme enhances also the activity of core enzyme fro- Escherichia coli. The formation of a hybrid between micrococcal sigma and E. coli core polymerase is also suggested by the influence of sigma on the oligomerisation of the enzyme from E. coli.

DNA, Viral↗
PubMed1977

Formation of a RNA polymerase sub-assembly composed of subunit alpha from Escherichia coli and of subunit beta from Micrococcus luteus.

Functionally equivalent subunits of RNA polymerase from Micrococcus luteus and Escherichia coli differ from each other in many molecular and antigenic properties. In spite of these differences, subunit alpha from E. coli and subunit beta from M. luteus form a complex alpha2beta, when incubated together. This complex binds rifampicin tightly, which the isolated subunits do not. The hybrid complex is very similar in its properties to the complex alpha2beta formed only from E. coli or M. luteus subunits. Since the sub-assembly alpha2beta from E. coli is reported to be an obligatory intermediate in the assembly process of complete RNA polymerase, the newly described hybrid sub-assembly may function similarly as an intermediate in the formation of the hybrid form of RNA polymerase described earlier.

DNA-Directed RNA Polymerases↗
PubMed1991

Lysodektose--a new trisaccharide from Micrococcus lysodeikticus which is transformed into an aminoxyl free radical with the loss of an electron.

A new trisaccharide 6-0-(2-deoxy-2-(N-methyl)-hydroxylamino-beta-D- glucopyranosyl)-alpha,alpha-trehalose named lysodektose has been isolated from Micrococcus lysodeikticus. In oxygenated solutions or in the presence of K3 Fe (CN)6 lysodektose is transformed into a long lived free radical. Spin trapping data are presented and functions are suggested for the substance.

Carbohydrate Sequence↗
PubMed1986

Purification and characterization of extracellular caseinolytic enzyme of Micrococcus sp. MCC-315 isolated from cheddar cheese.

Micrococcus sp. MCC-315, an organism isolated from Cheddar cheese, produced an extracellular calcium metalloenzyme. This protease was purified to homogeneity from culture supernatant by precipitation with ammonium sulfate (50 to 70% saturation) and gel filtration through Sephadex G-100, resulting in about 82 times increase of specific activity and 53% recovery of the enzyme. The protease exhibited a pH optimum at 10.6 for both whole casein and beta-casein. It had optimum activity for whole casein in the presence and absence of calcium++ at 60 and 50 degrees C, respectively, and at 37 to 40 degrees C for beta-casein with or without calcium++. The enzyme was stable at 45 degrees C but lost activity at higher temperatures. It was inhibited by heavy metal ions but calcium++, cobalt++, manganese++, strontium++, and iron++ had a slight stimulatory effect. The enzyme was inhibited completely and irreversibly by metal chelating agents. Calcium ions were required for maintenance of an active conformation of the enzyme. The enzyme had molecular weight of 28,900 and Michaelis constants 6.66 and 5.00 mg/ml for whole casein and beta-casein. Amino acid analysis of the hydrolyzed enzyme revealed the absence of sulfhydryl groups as was indicated also by lack of inhibition by thiol reagents.

Caseins↗
PubMed1980

Cerebral cyst infection with Micrococcus sedentarius. Case report.

A 7-year-old boy with congenital hydrocephalus and a left septate cerebral cyst presented with a shunt infection due to Micrococcus sedentarius, resistant to all penicillins. The shunt infection was persistent despite several courses of parenteral, intraventricular, and intracyst antibiotics. Evaluation of the ventricular fluid revealed adequate "killing power" against the patient's microorganism. No extracranial focus of infection could be found. Computerized tomographic scanning, along with air ventriculography, identified a noncommunicating area of the cerebral cyst. Only when communication between this location and the rest of the cyst was established were the antibiotics efficacious. Undercirculated areas of cerebrospinal fluid should be sought when shunt infections and ventriculitis persist in spite of adequate parenteral and local therapy in patients with brain cysts.

Bacterial Infections↗
PubMed1979

Preparation and antibacterial activity upon Micrococcus luteus of derivatives of iturin A, mycosubtilin and bacillomycin L, antibiotics from Bacillus subtilis.

Methylated and acetylated derivatives of iturin A and mycosubtilin and methylated derivatives of bacillomycin L were prepared and their antibacterial activity on Micrococcus luteus was compared with the activity of the original substance. the results obtained show the importance of polar groups for the antibiotic activity of the substances of iturin group.

Anti-Bacterial Agents↗