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At least 487 records · Page 27Linked to original sources
PubMed1979

Influence of temperature on ionic sparing effect and cell-associated cations in the moderate halophile, Micrococcus varians var. halophilus.

Cells of the moderately halophilic Micrococcus varians var. halophilus grew well in a chemically defined medium containing 1 to 3 M NaCl and 0.0103 M K+. The requirement for NaCl could be partially replaced by K+,:Li+ and Cs+. The efficiency of the sparing effect of these cations for NaCl was in order of K+ GReater than Li+ greater than Cs+. Increase in growth temperature was found to enchance the sparing effect of Li+ and Cs+ but not that of K+. Over the range of NaCl concentrations in which the cells grew well, cell-Na+ concentrations were similar to the medium NaCl concentrations while cellK+ concentrations were several-fold that in the medium. Cell-bound Na+ and K+ concentrations increased proportionally with medium NaCl concentration and growth temperature. The temperature-dependent cation accumulation was more obvious with K+ than Na+. The cell-associated Na+ + K+ concentrations were almost as high as or slightly higher than the external media which contained appropriate levels of NaCl regardless of the growth temperature.

Cesium↗
PubMed1978

[Action of egg lysozyme on representatives of the family Micrococcaceae. Its action on Micrococcus].

The results of the study of the effect of various concentrations of egg lysozyme on M. luteus and M. varians using 2 methods, i.e. serial dilutions in agar and turbidimetric are presented. It was found that the MIC of lysozyme for M. luteus ranged within wide limits, from less than 0.0003 to 1 mg/ml. M. varians was stable to lysozyme. The MIC for all the strains was 8 mg/ml. The turbidimetric method provided determination of general regularities in changes of the optical density in all the strains of M. luteus under the effect of various concentrations of lysozyme. On the basis of these data it was possible to consider the method as the most deep means for determining the intraspecies similarities in the surface structures of Micrococcus as compared to the method of serial dilutions in agar. The dynamics of the changes in the optical density of the M. luteus suspension markedly differed from that of M. varians.

Animals↗
PubMed1976

[Study of the structure of the histidine decarboxylase of Micrococcus sp. n. by the method of circular dichroism].

Ring dichroism spectra (RD) of histidine decarboxylase (HDC) from Micrococcus sp. n. at the regions of peptide bonds (200-240 nm) and aromatic amino acids (250-300 nm) absorption are studied. The treatment of RD spectra according to methods of Greenfield-Fasman, Saksena-Vetlaufer and Mayer permits to conclude that at the pH range within 4-8 the content of ordered structures of alpha-helix type comprises 20%, that of beta-structure type-40%, while the rest 40% are represented with polypeptide chain in a disordered globular state. When pH is varied from 1 to 12, the content of alpha-helices decreases from 17 to 5%. There are two distinct dichroic bands in the spectrum of aromatic chromophores absorption (at 270 and 290 nm), the former containing tirosine, tryptophane and phenylalanine residues and the latter being induced with triptophane residues. The study of HDC RD spectra at the regions of peptide bonds and aromatic acids absorption at different temperatures has shown that a part of triptophane, tyrosine and phenylalanine residues is in an ordered structure of the alpha-helix type. The HDC undergoes irreversible changes under heating to 70 degrees and in 8 M urea. 5 M guanidine chloride eliminates the ordered HDC structure, while sodium dodecylsulphate at concentrations up to 1% does not affect the enzyme structure.

Carboxy-Lyases↗
PubMed1982

[Comparison of the lytic effect of gramicidin S and its derivatives on Bacillus megaterium and Micrococcus lysodeikticus protoplasts].

Essential differences were found between the lytic action of gramicidin S. on Bacillus megaterium protoplasts and that on Micrococcus lysodeikticus protoplasts. When protoplasts were suspended in a sucrose solution in phosphate buffer, the lytic activity of gramicidin S toward B. megaterium protoplasts increased with a rise in the antibiotic concentration; the lytic action of gramicidin S on M. lysodeikticus protoplasts was characterized by a complex concentration dependence. Gramicidin S derivatives lacking basic properties since the amino groups of their ornithine residues were either substituted with urea residues (carbamoyl gramicidin) of acetylated (diacetyl gramicidin) showed a high lytic activity toward the both bacterial species. In contrast to gramicidin S, the derivatives virtually did not change the permeability of cytoplasmic membranes when they acted on intact cells. In the absence of phosphates (when protoplasts were suspended in an aqueous sucrose solution), the lytic activity of gramicidin S decreased while carbamoyl gramicidin and diacetyl gramicidin still were capable of causing lysis of M. lysodeikticus protoplasts though not of B. megaterium protoplasts.

Bacillus megaterium↗
PubMed1983

Lysine production from hydrocarbon by Micrococcus varians 2Fa.

A bacterium isolated from Assam (India) soil was found to accumulale l-lysine from hydrocarbon and was identified as a strain of Micrococcus varians. The strain is able to grow and accumulate lysine in a purely synthetic medium though supplementation of the synthetic medium with casamino acids significantly improves the yield. The yield of l-lysine under optimal conditions was found to be 2.6 g X 1(-1) of the compound isolated in crystalline form.

Alkanes↗
PubMed1983

[Submergence of Micrococcus lysodeikticus F1-ATPase into the hydrophobic phase of the membrane, using 2,4,6-trinitrobenzosulfonate and 12-0-(azidoformyl) stearic acid methyl ester].

The accessibility of F1-ATPase from Micrococcus lysodeikticus in solution and in the membrane for the specific water-soluble NH2-group reagent, 2,4,6-trinitrobenzosulfonate (TNBS), was studied. Incubation of the soluble factor F1 with 50 mM TNBS pH 8.3 results in incorporation of 58.6 +/- 4.4 trinitrophenyl residues per mole of enzyme. At the same time F1-ATPase isolated from TNBS-pretreated membranes contains 27.2 +/- 2.0 TNP-residues per mole of enzyme. It is assumed that the different accessibility of F1-ATPase for TNBS in solution and in the membrane is due to incorporation of F1-ATPase into the membrane. Study of membrane F1-ATPase interaction with the radioactive lipid-soluble photoreactive label, 12-0-(azidoformyl) stearic acid methyl ester demonstrated that F1-ATPase does not immediately interact with the lipid phase of the membrane. It is suggested that membrane F1-ATPase may be enveloped by hydrophobic proteins.

Affinity Labels↗
PubMed1984

Photoaffinity cross-linking of the coupling factor 1 from Micrococcus luteus by 3'-arylazido-8-azido-ATP.

The vicinity of nucleotide binding sites and the mechanism of ATP synthesis/hydrolysis have been studied with the bifunctional photosensitive ATP analog 3'-arylazido-8-azido-ATP. 3'-Arylazido-8-azido-ATP is hydrolyzed by the F1-ATPase from Micrococcus luteus in the absence of ultraviolet light. Irradiation, by ultraviolet light, of F1-ATPase in the presence of 3'-arylazido-8-azido-ATP results in the specific formation of cross-links between alpha and beta subunits. The results suggest that a hydrolytic nucleotide binding site is located on a beta subunit at or near an alpha subunit, probably at the interface between these subunits. Such a constellation would permit direct subunit-subunit interactions during ATP synthesis/hydrolysis.

Adenosine Triphosphate↗
PubMed1980

Comparison of the cleavage of pyrimidine dimers by the bacteriophage T4 and Micrococcus luteus UV-specific endonucleases.

A comparison was made of the activity of the UV-specific endonucleases of bacteriophage T4 (T4 endonuclease V) and of Micrococcus luteus on ultravilet light-irradiated DNA substrates of defined sequence. The two enzymes cleave DNA at the site of pyrimidine dimers with the same frequency. The products of the cleavage reaction are the same, suggesting that the scission of DNA by T4 endonuclease V occurs via the combined actin of a pyrimidine dimer specific DNA glycosylase and an apyrimidinic-apurinic (AP) endonuclease as was recently shown for the M. luteus enzyme. The pyrimidine dimer DNA-glycosylase activity of both enzymes is more active on double-stranded DNA than it is on single-stranded DNA.

Base Sequence↗
PubMed1981

Early steps of excision repair of cyclobutane pyrimidine dimers by the Micrococcus luteus endonuclease. A three-step incision model.

The early steps of excision repair of cyclobutane pyrimidine dimers are investigated. It is demonstrated that the apurinic/apyrimidinic endonuclease associated with the Micrococcus luteus uv-specific endonuclease cleaves the phosphodiester bond on the 3' side of the deoxyribose leaving a 3' hydroxy terminus and a 5' phosphoryl terminus. This nick is not a substrate for T4 polynucleotide ligase. The 3' base-free deoxyribose terminus is not a substrate for either the polymerase or the 3' to 5' exonuclease activities of Escherichia coli DNA polymerase I. However, the 3' terminus of the nick is converted to a substrate for DNA polymerization by the action of a 5' apurinic/apyrimidinic endonuclease. A three-step model for the incision step of excision repair of cyclobutane pyrimidine dimers is presented.

Alkaline Phosphatase↗
PubMed1978

Septic shock with Micrococcus luteus.

Micrococcus luteus is considered a non-pathogenic saprophyte of human skin and eye. Disease in man caused by this organism is not recorded in medical literature. We present a case of septic shock cause by M luteus. The value of this report is to document the pathogenicity of coagulase-negative staphylococci in patients without valvular heart disease, surgically implanted artifificial prosthetic devices, or polyethylene intravenous catheters.

Aged↗
PubMed1983

[Radioresistance mechanisms of Micrococcus radiodurans].

The modern conceptions on the molecular mechanisms of Micrococcus radiodurans viability under the action of ionized radiation have been considered. Factors providing a high level of the bacterium radioresistance-the peculiarities of the cell wall structure, membranes, DNA, the redundancy of genetic information, the multiplicity of sites of DNA attachment to the membrane, a high level of antioxidant and antiradical systems-have been analysed. It has been shown that the efficiency of accurate, error-free, well balanced DNA repair system in connection with M. radiodurans properties mentioned provides a high radiation resistance of this microorganism.

Carotenoids↗
PubMedDate not supplied

[Genetic control of the processes of postradiation repair of a compact chromosome in Micrococcus radiodurans cells].

X-irradiation of Micrococcus radiodurans cells with sublethal doses caused disturbances in the structure of a membrane-bound compact chromosome. Recovery of the compact chromosome occurred during the postirradiation incubation of the wild type cells and cells of the UVS-17 mutant deficient in DNA-polymerase. This process was blocked in cells of rec-30 mutant with the impaired system of genetic recombination: this is indicative of an important role played by rec-30 gene product in the postirradiation recovery of the compact chromosome in M. radiodurans cells.

Chromosomes, Bacterial↗
PubMed1983

Effect of cordycepin(3'-deoxyadenosine) on excision repair of 5,6-dihydroxy-dihydrothymine-type products from the DNA of Micrococcus radiodurans.

Cordycepin(3'-deoxyadenosine), a nucleoside analog, has been shown to enhance radiation-induced cell killing. In an effort to elucidate the possible mechanism for enhancement of cell killing, the effect of cordycepin on the excision repair of radiation-induced 5,6-dihydroxy-dihydrothymine-type (t') products from the DNA of wild type Micrococcus radiodurans was investigated. The capacity of M. radiodurans to excise nondimeric (t') products from its DNA was significantly impaired after cordycepin treatment. The results suggest that the increased radiation sensitivity of cordycepin-treated cells could be due to alterations in cellular processes that repair DNA damage.

Cell Survival↗
PubMedDate not supplied

[Action of the steroid glycoside deltonin on the bacterial membranes of Micrococcus lysodeikticus].

A slight detergent-like effect of steroid glycoside deltonine from Dioscorea deltoidea on the bacterial membranes of Micrococcus lysodeikticus was detected which resulted in the breaking of the osmotic barrier of protoplasts and in the loss from the membranes of small fragments containing the dehydrogenases of the respiratory chain but without cytochromes. These small fragments still retained the membrane structure.

Cell Membrane↗
PubMed1984

[Physico-chemical characteristics of catalases from Micrococcus sp. n].

The physico-chemical properties of heme-containing and non-heme catalases isolated from the cell culture of Micrococcus sp. n. grown under intensive aeration were studied. The enzyme preparations were homogenous during polyacrylamide disc electrophoresis. The spectral and functional properties of the enzymes (e. g. specific activity, subunit molecular weight, quaternary structure, amino acid composition, immunoprecipitability, N-terminal amino acid sequences) were investigated. Monocrystals of non-heme catalase applicable for an X-ray analysis were grown and examined by X-ray spectroscopy. Both enzymes were stable upon storage in 40% ammonium sulfate for 2 months and resistant to lyophylization without any significant loss of their activity. Non-heme catalase is apparently an independent enzyme which is not derived from heme-containing catalase via dissociation, limited proteolysis or heme cleavage.

Amino Acids↗
PubMed1984

[Proteolytic resistance and thermostability of catalase and histidine decarboxylase from Micrococcus sp. n].

Catalase from Micrococcus sp. n. is not hydrolyzed by trypsin at the protein/protease (pn/pe) exceeding 10/1. Histidine decarboxylase (HDC) loses 50% of activity after the first nine minutes of hydrolysis at the pn/pe ratio equal to 6/1, followed by a slow linear inactivation. Investigation of thermal stability at varying pH and temperatures demonstrated that catalase and HDC preserve 70-80% of activity after 5 minutes of incubation at 72 degrees C only at pH approaching the optimal pH of enzymatic activity (pH 7.45 for catalase and pH 5.55 for HDC).

Carboxy-Lyases↗
PubMed1981

[Structure of the Micrococcus lysodeikticus respiratory chain using low concentrations of Triton X-100 and glutaric aldehyde].

Using low (0.0025 -- 0.025%) concentrations of Triton X-100, the correlation between the decrease of NADN- and malate oxidase activities and NADH- and malate dehydrogenase release in large fragments of Micrococcus lysodeikticus membranes was established. This was accompanied by membrane suspension clearance and a decrease of microviscosity of the membrane lipid component. Using NADH-dehydrogenase, it was shown that the attachment of NADH-dehydrogenase to the membrane treated with glutaric aldehyde occurs in two steps, this being indicative of different environment of this enzyme in the membrane. The data obtained are discussed in terms of laterally heterogenous structure of the bacterial membrane with respect to the electron transport enzymes, in particular in favour of an existence of individual sites of the membrane containing dehydrogenases rather than other respiratory chain components.

Alcohol Oxidoreductases↗
PubMed1978

The structure of a periodic cell wall component (HPI-layer of Micrococcus radiodurans).

The hexagonally packed interlayer (HPI-layer) from Micrococcus radiodurans cell walls has been studied by electron microscopy and subsequent digital image processing. The most prominent feature in the average images is a "complex" shaped like a "toothed wheel", which is perforated by a central pore and interconnected by fine spokes. This basic structural element is tentatively interpreted to represent the bulk of HPI-layer protein, intercalated by the other constituents: lipids, carotenoids and carbohydrates. It is suggested that the "toothed wheel" structure is a quite common element of periodic bacterial surface layers and that the different spacings observed with various species are due to variable amounts of intercalating material.

Bacterial Proteins↗