Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Micrococcus”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 307 records · Page 17Linked to original sources

Purification of several bacteriolytic enzymes by affinity chromatography on lysozyme-lysate of Micrococcus lysodeikticus cell wall coupled with sepharose.

Using lysozyme-lysate of Micrococcus lysodeikticus cell wall coupled with Sepharose, several bacteriolytic enzymes were purified from crude preparations of animal and microbial origin. Quail egg-white, human milk and salivary lysozymes [EC 3.2.1.17] were adsorbed onto the adsorbent at pH 5-7 and eluted with 2M NaCl at pH 10. By means of these treatments, lysozymes were purified 20-250 fold with activity recoveries of 60-80%, and the quail lysozyme thus purified was shown to be discelectrophoretically homogeneous. Some bacteriolytic enzymes of microbial origin were also highly purified by using this affinity adsorbent. A bacterial lysozyme from Bacillus sp. ML-208 showed high affinity for the ligand and was not eluted under the conditions mentioned above, but was recovered by elution with 2M guanidine-HCl at pH 5.8, resulting in a 500-fold increase in the specific activity. A Pseudomonas-lytic enzyme from Streptomyces sp. P-51 was easily released from the adsorbent by elution with 0.5M NaCl at pH 5.0. A staphylolytic F2 enzyme from S. griseus S-35 and a chitinase [EC 3.2.1.14] from yam, both of which were completely inert toward M. lysodeikticus cell wall, passed through the adsorbent column. A modified ligand, in which muramic acid and glucosamine residues were N,O-acetylated, failed to adsorb any of these animal and bacterial lysozymes. Some of the enzymatic properties and bacteriolytic action spectra of these purified enzymes are also described in this paper in comparison with those of hen egg-white lysozyme.

Animals↗

Comparative specificity of geranylgeranyl pyrophosphate synthetase of Micrococcus lysodeikticus and pumpkin.

Comparative studies on the substrate specificity of geranylgeranyl pyrophosphate synthetase from Micrococcus lysodeikticus and from pumpkin seedlin revealed that geranyl pyrophosphate was the most active of the natural substrates for the pumpkin enzyme, whereas it was the least active for the bacterial enzyme. A marked difference was also observed between the enzymes from these two sources as regards the reactivity of 3-methyl-2-alkenyl pyrophosphates as a function of the size of the alkyl group.

Kinetics↗

Effects of polyamines on the degradation of ribonucleic acids by polynucleotide phosphorylase of Micrococcus luteus.

The effects of polyamines on the breakdown of synthetic polynucleotides [poly(A), poly(C), and poly(U)] by polynucleotide phosphorylase [polyribonucleotide: orthophosphate nucleotidyltransferase, EC 2.7.7.8] from Micrococcus luteus have been studied. Although the breakdown of all the synthetic polynucleotides tested was stimulated by polyamines, the degree of stimulation by polyamines was in the order poly(C) greater than poly(A) greater than poly(U) at pH 7.5. However, the difference in degree of stimulation among polynucleotides decreased as the pH or monovalent cation concentration was increased. In the presence of heparin, an inhibitor of polynucleotide phosphorylase hydrolysis of polynucleotides, spermidine clearly stimulated the breakdown of poly(C) and poly(A), while the breakdown of poly(U) was stimulated only slightly by the addition of spermidine. Although binding of [14C]spermine to polynucleotide phosphorylase was observed by gel filtration, the amount of spermine bound to the enzyme was much less than that to RNA.

Binding Sites↗

Biosynthesis of menaquinones. Enzymatic prenylation of 1,4-dihydroxy-2-naphthoate by Micrococcus luteus membrane fractions.

1,4-Dihydroxy-2-naphthoate:polyprenyltransferase was detected in the membrane fraction from Micrococcus luteus. The specificity of the enzyme ws so tolerant as regards the prenyl-donating substrate that prenyl pyrophosphates ranging in chain length from C15 to C45 were active as substrates. The monophosphate esters were also active, though the reactivities were much lower than those of the corresponding pyrophosphates. The enzyme showed rigorous specificity with respect to the aromatic substrate. Neither 1,4-dihydroxynaphthalene nor its 2-methyl derivative was active at all. 1,4-Dihydroxy-3-methyl-2-naphthoate could be prenylated to afford menaquinone, but the reactivity was much less than that of its demethyl derivative. These results support the view that menaquinone biosynthesis involves the prenylation of 1,4-dihydroxy-2-naphthoate prior to decarboxylation or methylation.

Alkyl and Aryl Transferases↗

Geranylgeranyl pyrophosphate synthetase lacking geranyl-transferring activity from Micrococcus luteus.

Geranyl pyrophosphate synthetase, which catalyzes the condensation of isopentenyl pyrophosphate with dimethylallyl pyrophosphate to give geranyl pyrophosphate, was purified 490-fold from Micrococcus luteus extracts by DEAE-Sephadex, hydroxylapatite, and Sephadex G-100 column chromatography. The enzyme has a pH optimum at 7.7 and the molecular weight was estimated to be 70,000 by Sephadex gel filtration. The Km values for isopentenyl pyrophosphate and dimethylallyl pyrophosphate were 8 microM and 62 microM, respectively. The enzyme required Mg2+ for maximum activity. Tween 80 showed a stimulative effect whereas Triton X-100 was rather inhibitory on the enzyme activity. Inorganic pyrophosphate and iodoacetamide were both potent inhibitors of the enzyme. The purified enzyme fraction was also capable of catalyzing the synthesis of geranylgeranyl pyrophosphate from isopentenyl pyrophosphate and farnesyl pyrophosphate, but lacked geranyl-transferring activity. The catalytic activities of geranylgeranyl pyrophosphate synthesis and geranyl pyrophosphate synthesis were affected differently by iodoacetamide and Triton X-100. This enzyme fraction may be a mixture of two enzymes, geranyl pyrophosphate synthetase and geranylgeranyl pyrophosphate synthetase catalyzing the reactions of C5 greater than C10 and C15 greater than C20, respectively, or a single enzyme with two independent catalytic sites responsible for the C5 greater than C10 and C15 greater than C20 reactions. In any case, the existence of a new geranylgeranyl pyrophosphate synthetase different from the known geranylgeranyl pyrophosphate synthetase catalyzing the continuous condensation reaction of C5 greater than C10 greater than C15 greater than C20 was demonstrated.

Alkyl and Aryl Transferases↗

Biosynthesis of UDP-N-acetyl-D-glucosaminuronic acid and UDP-N-acetyl-D-mannosaminuronic acid in Micrococcus luteus.

The occurrence and formation of UDP-N-acetyl-D-glucosaminuronic acid (UDP-GlcNAcA) and UDP-N-acetyl-D-mannosaminuronic acid (UDP-ManNAcA) were studied in Micrococcus luteus ATCC 4698. UDP-N-acetylhexosaminuronic acid separated from D-cycloserine-inhibited cells was shown to be a mixture of UDP-GlcNAcA and UDP-ManNAcA in the ratio of 87:13, whereas that obtained from untreated cells was a 96:4 mixture of these two nucleotides. Crude enzyme preparations obtained from the supernatant fraction of cells catalyzed the NAD+-dependent conversion of UDP-GlcNAc into UDP-GlcNAcA and UDP-ManNAcA. Studies on the partial separation and properties of enzymes revealed that UDP-GlcNAcA is synthesized directly from UDP-GlcNAc by the action of UDP-GlcNAc dehydrogenase and that UDP-ManNAcA is synthesized from UDP-GlcNAc through the successive actions of UDP-GlcNAc 2-epimerase and UDP-ManNAc dehydrogenase. However, enzymatic conversion of UDP-GlcNAcA to UDP-ManNAcA was not detected. Ammonium sulfate protects both dehydrogenases from inactivation during storage and incubation. Partially purified UDP-GlcNAc dehydrogenase required dithiothreitol and the particulate fraction for its full activity. The apparent Km values of UDP-GlcNAc dehydrogenase for UDP-GlcNAc and NAD+ were 0.28 and 1.43 mM, respectively. The optimum pH of this enzyme was higher than 9 in Tris-HCl buffer. p-Chloromercuribenzoate at 27 microM as well as 10 mM ethanol almost completely inhibited the UDP-GlcNAc dehydrogenase reaction.

Carbohydrate Dehydrogenases↗

Comparative study of "Micrococcus sp." strains CCM 168 and CCM 1405 and members of the genus Salinicoccus.

Two culture collection strains, CCM 168 and CCM 1405, previously assigned to the genus Micrococcus were shown by molecular chemical characterization to belong to the genus Salinicoccus. A more detailed comparison of the physiological and biochemical properties of these strains and comparison with the type strain of Salinicoccus roseus indicated high degrees of relatedness among the three strains. DNA-DNA hybridization studies confirmed the high degrees of relatedness. All of the data demonstrate quite clearly that strains CCM 168 and CCM 1405 are members of the species S. roseus.

Amino Acid Sequence↗

Induction of necrosis factor-alpha and interleukin-6 in mice in vivo and in murine peritoneal macrophages and human whole blood cells in vitro by Micrococcus luteus teichuronic acids.

Earlier studies showed that Micrococcus luteus cells and cell walls induced anaphylactoid reactions leading to death, in some instances within 1 h, in C3H/HeN mice primed with muramyl dipeptide (MDP). They also induced serum cytokines in the surviving mice. The present study investigated the structural components responsible for these activities. Teichuronic acids, a component of M. luteus cell walls, induced tumour necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) in MDP-primed C3H/HeN mice. Peptidoglycans had little effect on the cytokine-inducing activities. Reducing teichuronic acids, i.e., teichuronic acids whose carboxyl groups had been reduced, lost their cytokine-inducing activities. Neither peptidoglycans nor teichuronic acids induced anaphylactoid reactions in the MDP-primed mice. Purified teichuronic acids also induced TNF-alpha and IL-6 production in C3H/HeN murine peritoneal macrophages and human whole-blood cells in the culture, but reduced teichuronic acids did not. The purified teichuronic acids induced no TNF-alpha and only low levels of IL-6 in MDP-primed C3H/HeJ mice, and neither cytokine in peritoneal macrophage cultures from C3H/HeJ mice with a single point of mutation in Toll-like receptor 4 (TLR4) gene. These findings suggest that induction of cytokines by teichuronic acids is mainly TLR4-dependent.

Acetylmuramyl-Alanyl-Isoglutamine↗

Protection of cell viability and respiratory quinone levels by carotenoid in Micrococcus lysodeikticus (M. luteus).

Viability and respiratory activity of post-exponential phase cultures of Micrococcus lysodeikticus (M. luteus) decreased with time more rapidly in carotenoidless mutants than in a parent pigmented strain. The concentration of menaquinone, the respiratory quinone, was found to be low in carotenoidless mutants and in cultures of the pigmented strain where carotenoid synthesis had been partially blocked by diphenylamine. Cell suspensions incorporated [2-14C]mevalonate into menaquinone. Carotenoidless strains incorporated label at substantially higher rates than did the pigmented wild-type strain. Gently prepared membranes of M. lysodeikticus also incorporated mevalonate into menaquinone suggesting that the enzymes for the isoprenoid pathway are bound (loosely) to the membrane. Carotenoidless membranes with low concentrations of menaquinone incorporated radioactivity from [2-14C]mevalonate into quinone more rapidly than did membranes from the wild-type. Azide inhibited the incorporation but n-heptyl-4-hydroxyquinolone-N-oxide did not. It is concluded that the low concentrations of menaquinone in carotenoidless strains are due to rapid breakdown of the quinone. Carotenoid is therefore seen as protecting menaquinone from breakdown by factors as yet unidentified.

Carotenoids↗

Isolation and properties of strains of Micrococcus (Deinococcus) radiodurans unable to excise ultraviolet light-induced pyrimidine dimers from DNA: evidence for two excision pathways.

A mutant of Deinococcus (formerly Micrococcus) radiodurans (strain 302, mutant in mtcA) sensitive to both the lethal effect of mitomycin C and the mutagenic effect of simple alkylating agents, but having wild-type resistance to UV light, was treated with the mutagen N-methyl-N'-nitro-N-nitrosoguanidine in an attempt to isolate strains deficient in the ability to excise UV-induced pyrimidine dimers. Three strains were isolated that were UV-sensitive, but had wild-type resistance to the lethal effect of methyl methanesulphonate and all were shown to be unable to excise pyrimidine dimers. The three strains UVS9, UVS25 and UVS78 had, in addition to the mutation in mtcA, mutations in loci designated uvsC, uvsD and uvsE, respectively. When the mutant mtcA gene was replaced by its wild-type allele in all three strains they became UV- and mitomycin C-resistant. On incubating the double mutants UVS9, UVS25 and UVS78 with wild-type DNA about 50% of the transformants selected for UV resistance were mitomycin C-sensitive and about 50% resistant depending on whether the mutant mtcA or the uvsC, D or E genes had been replaced by their wild-type alleles. Although strains mutant singly in uvsC, D or E were UV-resistant the rates of excision of pyrimidine dimers differed between them and was slower in all of them than in the wild-type and strain 302. The results indicate that wild-type D. radiodurans possesses two pathways for the excision of pyrimidine dimers and that mutational blocks in both must exist for the excisionless phenotype to be expressed.

DNA Repair↗

Biotransformation of 3-methylphthalate by Micrococcus sp. strain 12B.

When Micrococcus strain 12B grown on o-phthalate was incubated with 3-methylphthalate, three compounds accumulated. These were shown to be 2-pyrone-3-methyl-4,6-dicarboxylic acid, 3,4-dihydroxy-6-methylphthalic acid, and 5-hydroxy-3-methyphthalic acid, all previously undescribed. A pathway for the formation of these compounds is proposed.

Biotransformation↗

Putrescine oxidase of Micrococcus rubens: primary structure and Escherichia coli.

The flavin adenine dinucleotide (FAD)-containing putrescine oxidase of Micrococcus rubens catalyses the oxidative deamination of putrescine. The amino acid sequences of the NH2-termini of the mature enzyme and lysyl-endopeptidase-generated fragments were determined for preparation of synthetic oligonucleotides as hybridization probes for cloning. A 4.4 kb BamHI fragment which contained DNA sequences hybridizing to the probes was cloned in pUC19 in Escherichia coli. The nucleotide sequence together with the determined amino acid sequences revealed that this enzyme consists of 480 amino acids (M(r) 52,000) and contains an FAD-binding consensus sequence at its NH2-terminal portion. In front of the transcriptional start point, which is 28 bases upstream of the initiation codon as determined by primer extension, -35 and -10 sequences similar to typical prokaryotic promoter consensus sequences are present. E. coli JM109 containing the putrescine oxidase gene just downstream of the lac promoter in pUC18 produced a large amount of this protein when grown at 37 degrees C but in the enzymically inactive form of inclusion bodies. However, cultivation of the recombinant E. coli cells at temperatures below 30 degrees C led to production of active enzyme (20 times as much as produced by the original M. rubens strain).

Amino Acid Sequence↗

Plasmid-borne macrolide resistance in Micrococcus luteus.

A plasmid designated pMEC2 which confers resistance to erythromycin, other macrolides, and lincomycin was detected in Micrococcus luteus strain MAW843 isolated from human skin. Curing of this approximately 4.2 kb plasmid from the host organism resulted in erythromycin sensitivity of the strain. Introduction of pMEC2 into a different M. luteus strain conferred erythromycin resistance upon this strain. Macrolide resistance in M. luteus MAW843 was an inducible trait. Induction occurred at subinhibitory erythromycin concentrations of about 0.02-0.05 micro g ml(-1). Erythromycin and oleandomycin were inducers, while spiramycin and tylosin exerted no significant inducer properties. With heterologous expression experiments in Corynebacterium glutamicum, using hybrid plasmid constructs and deletion derivatives thereof, it was possible to narrow down the location of the plasmid-borne erythromycin-resistance determinant to a region of about 1.8 kb of pMEC2. Sequence analysis of the genetic determinant, designated erm(36), identified an ORF putatively encoding a 281-residue protein with similarity to 23S rRNA adenine N(6)-methyltransferases. erm(36) was most related (about 52-54% identity) to erythromycin-resistance proteins found in high-G+C Gram-positive bacteria, including the (opportunistic) pathogenic corynebacteria Corynebacterium jeikeium, C. striatum, C. diphtheriae and Propionibacterium acnes. This is believed to be the first report of a plasmid-borne, inducible antibiotic resistance in micrococci. The possible role of non-pathogenic, saprophytic micrococci bearing antibiotic-resistance genes in the spreading of these determinants is discussed.

Anti-Bacterial Agents↗

Involvement of a recombination repair function in disciplined cell division of Micrococcus radiodurans.

When a culture of the temperature-sensitive DNA mutant Micrococcus radiodurans tsI is irradiated with a sublethal dose of ultraviolet or ionizing radiation and is plated immediately, all the bacteria give rise, after 36 h incubation, to colonies identical to those derived from unirradiated bacteria. However, when the irradiated population is held at its restrictive temperature (39 degrees C) (restrictive temperature holding) for 3 h before being plated, less than 0-1% of the surviving bacteria give rise to normal colonies, the rest producing, after incubation for 96 h, small malformed colonies. Qualitatively, the same effect is observed when u.v.-irradiated wild-type M. radiodurans is incubated at 39 degrees C in the presence of nalidixic acid before plating. Compared with the loss of viability, the loss of normal colony development as a function of the radiation dose is sensitive, having I/e values of 210 ergs/mm2 for u.v. radiation and of 4 to 5 krad for 60Co gamma-radiation. These are identical to the radiation dose-response values of a recombination-deficient mutant of M. radiodurans. At first the abnormal colonies consist entirely of giant bacteria but eventually a few bacteria with normal morphology appear and because of their much faster generation time a highly sectored colony results. These colonies can be "rescued" by plating the irradiated bacteria held at 39 degrees C on agar containing pantoyl lactone, their growth being identical to that of unirradiated bacteria. Abnormal colony development is not a general phenomenon in temperature-sensitive mutants of M. radiodurans but occurs in those mutants which are sensitized to radiation when held at 39 degrees C. It is concluded that these abnormal colonies are produced as a result of a defect in a recombination function and that this function is also involved in the regulation of normal cell division.

Cell Division↗

The rate of recombination repair and its relationship to the radiation-induced delay in DNA synthesis in Micrococcus radiodurans.

The measurement of the time at which normal colony-forming ability returns in irradiated cultures of Micrococcus radiodurans tsI held at 30 degrees C can be used to estimate the time of completion of recombination repair. By comparing the times to complete such repair in populations given increasing radiation doses it is possible to calculate the rate of recombination repair. The rate was independent of the radiation dose; recombination could repair in one minute the damage caused either by 1-2 krad gamma radiation or 4 X 10(-6) J mm-2 u.v. radiation. The time taken for the normal rate of DNA synthesis to return in irradiated M. radiodurans tsI was measured under conditions identical to those used to measure recombination repair. The delay in DNA synthesis was 1-0 min per 1-2 krad gamma radiation and 1-0 min per 5-6 X 10(-6) J mm-2 u.v. radiation. The data suggest that the normal rate of DNA synthesis resumes immediately after the completion of recombination repair of gamma-induced damage, but before the completion of recombination repair of u.v.-induced damage. It is postulated that cell death at the lethal dose of u.v. radiation is caused by a second round of replication of DNA which is still being repaired by recombination.

Cobalt Radioisotopes↗

Micrococcus in the blood.

Eight isolates of micrococci from the bloodstream of six patients obtained under circumstances suggesting a pathogenic role were studied in detail. The organisms were remarkably uniform in cultural, biochemical and antibiotic-susceptibility characters. All strains showed high resistance to methicillin and hydrolysed arginine. The characters found did not correspond with those of any hitherto described species, but were closest to Micrococcus lylae.

Anti-Bacterial Agents↗

Reclassification of ATCC 9341 from Micrococcus luteus to Kocuria rhizophila.

Strain ATCC 9341, currently known as Micrococcus luteus, has been designated as a quality-control strain in a number of applications. It is also cited as the standard culture in several official methods and manuals, as well as the Code of Federal Regulations. Over the years, it has become apparent that ATCC 9341 does not resemble other M. luteus strains; however, its phenotypic characteristics alone were ambiguous. Recently, a polyphasic study was performed in which molecular data were combined with cytochemical properties and physiological characteristics. The results clearly indicate that ATCC 9341 is a member of the genus Kocuria. Thus, it is proposed to reclassify ATCC 9341 as Kocuria rhizophila and to alert users worldwide of this name change.

DNA, Bacterial↗

The structures of Micrococcus lysodeikticus catalase, its ferryl intermediate (compound II) and NADPH complex.

The crystal structure of the bacterial catalase from Micrococcus lysodeikticus has been refined using the gene-derived sequence both at 0.88 A resolution using data recorded at 110 K and at 1.5 A resolution with room-temperature data. The atomic resolution structure has been refined with individual anisotropic atomic thermal parameters. This has revealed the geometry of the haem and surrounding protein, including many of the H atoms, with unprecedented accuracy and has characterized functionally important hydrogen-bond interactions in the active site. The positions of the H atoms are consistent with the enzymatic mechanism previously suggested for beef liver catalase. The structure reveals that a 25 A long channel leading to the haem is filled by partially occupied water molecules, suggesting an inherent facile access to the active site. In addition, the structures of the ferryl intermediate of the catalase, the so-called compound II, at 1.96 A resolution and the catalase complex with NADPH at 1.83 A resolution have been determined. Comparison of compound II and the resting state of the enzyme shows that the binding of the O atom to the iron (bond length 1.87 A) is associated with increased haem bending and is accompanied by a distal movement of the iron and the side chain of the proximal tyrosine. Finally, the structure of the NADPH complex shows that the cofactor is bound to the molecule in an equivalent position to that found in beef liver catalase, but that only the adenine part of NADPH is visible in the present structure.

Amino Acid Sequence↗