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PubMed1983

Immunochemical analysis of Micrococcus lysodeikticus (luteus) F1-ATPase and its subunits.

The F1-ATPase from Micrococcus lysodeikticus has been purified to 95% protein homogeneity in this laboratory and as all other bacterial F1S, possesses five distinct subunits with molecular weights ranging from 60 000 to 10 000 (Huberman, M. and Salton, M.R.J. (1979) Biochim. Biophys. Acta 547, 230-240). In this communication, we demonstrate the immunochemical reactivities of antibodies to native and SDS-dissociated subunits with the native and dissociated F1-ATPase and show that: (1) the antibodies generated to the native or SDS-dissociated subunits react with the native molecule; (2) all of the subunits comprising the F1 are antigenically unique as determined by crossed immunoelectrophoresis and the Ouchterlony double-diffusion techniques; (3) antibodies to the SDS-denatured individual delta- and epsilon-subunits can be used to destabilize the interaction of these specific subunits with the rest of the native F1; and (4) all subunit antibodies as well as anti-native F1 were found to inhibit ATPase activity to varying degrees, the strongest inhibition being seen with antibodies to the total F1 and anti-alpha- and anti-beta-subunit antibodies. The interaction of specific subunit antibodies may provide a new and novel way to study further and characterize the catalytic portions of F1-ATPases and in general may offer an additional method for the examination of multimeric proteins.

Antigen-Antibody Complex↗
PubMed1993

Effect of H1 histone isoforms on the methylation of single- or double-stranded DNA.

The loosely and tightly bound H1 histone isoforms were shown to exert, on the in vitro methylation of linker DNA in H1-depleted oligonucleosomes, inhibitory or activating effects respectively similar to those previously shown in the methylation of Micrococcus luteus dsDNA. When assayed on the enzymic methylation of Micrococcus luteus ssDNA, addition of the tightly bound one resulted in a stimulation similar to that exerted on double-stranded bacterial DNA or on linker DNA from mammalian chromatin, while the loosely bound isoform had no effect whatsoever. The transformation of the "typical" loosely bound H1 isoform into its tightly bound counterpart can be visualized as being an essential event in the modulation of DNA methylation process in eukaryotic chromatin.

Cell Nucleus↗
PubMed2003

Proteins of the Rpf family: immune cell reactivity and vaccination efficacy against tuberculosis in mice.

It was shown recently that Mycobacterium tuberculosis expresses five proteins that are homologous to Rpf (resuscitation promoting factor), which is secreted by growing cells of Micrococcus luteus. Rpf is required to resuscitate the growth of dormant Micrococcus luteus organisms, and its homologues may be involved in mycobacterial reactivation. Mycobacterial Rpf-like products are secreted proteins, which makes them candidates for recognition by the host immune system and anti-Rpf immune responses potentially protective against reactivated tuberculosis. Here we report that the Rpf protein itself and four out of five of its mycobacterial homologues, which were administered as subunit vaccines to C57BL/6 mice, are highly immunogenic. Rpf-like proteins elicit immunoglobulin G1 (IgG1) and IgG2a responses and T-cell proliferation and stimulate production of gamma interferon, interleukin-10 (IL-10), and IL-12 but not IL-4 or IL-5. Both humoral and T-cell responses against these antigens show a high degree of cross-reactivity. Vaccination of mice with Rpf-like proteins results in a significant level of protection against a subsequent high-dose challenge with virulent M. tuberculosis H37Rv, both in terms of survival times and mycobacterial multiplication in lungs and spleens.

Animals↗
PubMed2000

Isolation and insecticidal effects of some bacteria from Euproctis chrysorrhoea L. (Lepidoptera: Lymantriidae).

In this study, we investigated the bacterial pathogens of Euproctis chrysorrhoea and tested for their insecticidal activities. Based on colony color and morphology, four isolates were determined. According to morphological, physiological and biochemical characters of the isolates, they were identified as Enterobacter aerogenes, Lactobacillus sp., Bacillus thuringiensis and Micrococcus luteus. The insecticidal effects of these bacterial isolates on third-fourth instar larvae of Euproctis chrysorrhoea were investigated. The highest insecticidal effect determined on this pest is 68% with Bacillus thuringiensis. The effects of the other isolates are 45% with Enterobacter aerogenes, 15% Micrococcus luteus and 0% with Lactobacillus sp.

Animals↗
PubMed2003

Microbial contamination of non-disposable instruments in otolaryngology out-patients.

Nosocomial infections are an important cause of morbidity and contaminated equipment may contribute to this. There has been little work concerning contamination of non-disposable equipment in Otolaryngology. This study investigates the efficacy of the cleaning regimen for non-disposable instruments in an Otolaryngology out-patients clinic. Instruments were swabbed before each clinic, when they had been autoclaved, then after use on patients, when they had been washed with detergent and chlorhexidine. Swabs of 86 instruments were cultured using standardized microbiological techniques. Fifteen instruments (17 per cent) were contaminated, most with coagulase negative staphylococci. Two specimens of Micrococcus luteus were cultured and one each of Pseudomonas aeruginosa, Acinetobacter lwoffii and Aureobacterium spp. Micrococcus luteus and coagulase negative staphylococci may represent skin contaminants, but Aureobacterium spp. and Acinetobacter lwoffii can be sources of nosocomial infection. Pseudomonas aeruginosa is a potentially serious pathogen and is implicated in the aetiology of otitis externa. These findings question the efficacy of the current cleaning techniques.

Cross Infection↗
PubMedDate not supplied

[Fine structure of mummified cells of microorganisms formed under exposure to a chemical analog of anabiosis autoinducer].

Under the influence of alkyl hydroxybenzene (C6-AHB) added to cell suspensions at a concentration of (1-5) x 10(-3) M, the cells of Saccharomyces cerevisiae, Micrococcus luteus, and Thioalkalivibrio versutus underwent dramatic changes in the ultrastructural organization of cell membranes, cytoplasm, and inclusions. In yeast suspension, the first changes were observed after 15 min in the structure of slit-like invaginations in the cytoplasmic membrane (CM): they were shortened and thickened. In the subsequent 30 to 60 min, CM ruptures were formed in the regions devoid of intramembrane protein particles and in the slit-like invaginations. After 24 h, complete disintegration of the intracellular membrane structures and conglomeration of the ribosomal part of the cytoplasm occurred. Similar changes were observed on the exposure of gram-positive and gram-negative bacteria to AHB. However, the cell wall in all the microorganisms studied was not destroyed, and in Micrococcus luteus it was even thickened. These mummified forms were preserved as morphologically intact but nonviable cells for more than three years of observations. By their ultrastructural characteristics, these mummified forms of microorganisms were similar to the fossilized microorganisms discovered by us in fibrous kerite. The concept of micromummies was formulated. AHB are supposed to play an important role in the process of fossilization of microorganisms in nature.

Adaptation, Physiological↗
PubMed2004

Antimicrobial spectrum, production and mode of action of staphylococcin 188 produced by Staphylococcus aureus 188.

Staphylococcus aureus 188 has been shown to produce bacteriocin-like inhibitory substance known as staphylococcin 188. It has a broad-activity spectrum against Micrococcus luteus, Streptococcus pneumoniae, Streptococcus faecalis, Streptococcus viridans, Corynebacterium diphtheriae and several staphylococcus species. The arbitrary unit of staphylococcin 188 against Micrococcus luteus was 1280 AU/mL. Its production with simultaneous measurement of activity was monitored and was found to produce maximum amount of staphylococcin after 7 hours of incubation. Mode of action of the staphylococcin 188 on the sensitive cells was bactericidal rather than bacterioloytic.

Journal Article↗
PubMed1975

Interaction of wheat-germ agglutinin with bacterial cells and cell-wall polymers.

Wheat germ agglutinin was found to agglutinate cells of Escherichia coli PAT 84, Micrococcus luteus, Staphylococcus aureus H, and of S. aureus 52A5, but not cells of S. aureus 52A2. Interaction of wheat germ agglutinin with a soluble linear peptidoglycan secreted by Micrococcus luteus and with the teichoic acid of S. aureus H was demonstrated by agar gel diffusion, quantitative precipitation and inhibition of hemagglutination of trypsinized rabbit erythrocytes. No interaction could be demonstrated with the teichoic acid from a phage-resistant mutant (S. aureus 52A2) which lacks A-acetyl-D-glucosamine residues. All interactions were specifically inhibited by low concentrations of chitotriose (GlcNAcbeta1 leads to 4GlcNAcbeta1 leads to 4GlcNAc) and the bacterial cell wall tetrasaccharide, GlcNAcbeta1 leads to 4MurNAcbeta1 leads to 4GlcNAcbeta1 leads to 4MurNAc. Hemagglutination-inhibition experiments showed that the linear peptidoglycan and the teichoic acid of S. aureus H were several thousand times more potent inhibitors of wheat germ agglutinin than was N-acetyl-D-glucosamine. Comparison of the efficiency of different saccharides in inhibition of hemagglutination and precipitation of polymers by wheat germ agglutinin, strongly suggests that secondary, non-specific interactions contribute to the binding of the lectin to the polymers.

Agglutination Tests↗
PubMed2004

Substrate specificities of several prenyl chain elongating enzymes with respect to 4-methyl-4-pentenyl diphosphate.

In order to develop synthetic methods for biologically active homoallylic terpene sulfates, we examined the applicability and substrate specificities of several prenyl chain elongating enzymes with respect to 4-methyl-4-pentenyl diphosphate (homoIPP). The reaction of dimethylallyl diphosphate with homoIPP by use of Bacillus stearothermophilus (all-trans)-farnesyl diphosphate synthase resulted in efficient yields of cis-(yield: 45.9%) and trans-4,8-dimethylnona-3,7-dien-1-ol (homoGOH, 25.5%), which has a carbon skeleton of 4,8-dimethylnona-3-en-1-sulfate, an antiproliferative compound from a marine organism (Aiello, A. et al., Tetrahedron, 53, 11489-11492 (1997)). The homoIPP was found to be also active as a homoallylic substrate in place of isopentenyl diphosphate for Sulfolobus acidocaldarius geranylgeranyl diphosphate synthase to give diphosphate of cis- and trans-4,8,12-trimethyltrideca-3,7,11-trien-1-ol, for Micrococcus luteus B-P 26 hexaprenyl diphosphate synthase to give cis- and trans-4,8,12,16-tetramethylheptadeca-3,7,11,15-tetraen-1-ol (homoGGOH), and for Micrococcus luteus B-P 26 undecaprenyl diphosphate synthase to give cis-homoGGOH exclusively.

Alkyl and Aryl Transferases↗
PubMed1997

Relationship between antibacterial activity and cell surface binding of lactoferrin in species of genus Micrococcus.

Human lactoferrin was bactericidal in vitro for Micrococcus luteus but not for other Micrococcus species (M. radiophilus, M. roseus and M. varians). A correlation between the binding of lactoferrin to the bacterial surface and the antimicrobial action was observed. Viability assays showed that ferric, but not ferrous, salts prevented binding and consequently M. luteus was not killed. The unsaturated form of lactoferrin showed a greater affinity than that of the iron-saturated molecule for lipomannan, a lipoglycan present on the cell wall of M. luteus, supporting the role for lipomannan as one of the possible binding sites of lactoferrin on M. luteus.

Anti-Bacterial Agents↗
PubMed1972

Microbial uptake of lead.

Micrococcus luteus and Azotobacter sp. cells grown in broth in contact with a dialysis membrane containing lead bromide were found to immobilize 4.9 and 3.1 x 10(2) milligrams of lead per gram of whole cells, on a dry weight basis, respectively. Culture turbidity and cell count measurements on these and other cell cultures show that lead bromide, lead iodide, and lead bromochloride in concentrations approaching solubility limits have no detectable effect on overall growth rate and cell viability. Analyses of cellular subfractions reveal that fractions of cell wall plus membrane contain 99.3 and 99.1 percent of the lead found associated with Micrococcus luteus and Azotobacter sp., respectively. The remainder is found associated with the cytoplasmic fractions.

Azotobacter↗
PubMed1997

Liposome-encapsulated ampicillin: physicochemical and antibacterial properties.

The objectives of this study were to develop high-performance liquid chromatography (HPLC) and antibacterial assays for ampicillin encapsulated in multilamellar liposomes (MLV) and investigate the physicochemical and antibacterial properties of ampicillin-liposome systems. The major findings were fourfold. First, ammonium acetate (0.575%) in methanol:water (450:550; v/v), adjusted to pH 7.2, was suitable as the mobile phase for the HPLC determinations of ampicillin in both aqueous and liposomal systems. This mobile phase also provided (alone or with additional methanol) complete dissolution of liposomal assay samples in a precolumn treatment that made all of the encapsulated drug available for chromatography. Multiple samples were assayed without any technical limitations. Second, the growth-inhibition antibacterial assay developed, which used the USP test organism Micrococcus Luteus and paper disks, was quantitative for both free and liposome-encapsulated ampicillin. Third, the physicochemical properties of encapsulated ampicillin include encapsulation efficiencies of 10 to 50% for liposome concentrations in the range 10-200 mM (lipid), and a single rate constant to sufficiently and quantitatively describe the diffusion of encapsulated ampicillin, with half-lives in the range of 40 h. Fourth, the biological properties include the first direct evidence that encapsulated ampicillin retains full biological activity; that is, liposome-encapsulated ampicillin was active against extracellular bacterial colonies of Micrococcus luteus. Furthermore, encapsulation enhanced ampicillin stability. For example, free ampicillin in an aqueous solution that was stored for 5 weeks at 4 degrees C lost 50% of its initial activity, whereas liposome-encapsulated ampicillin (freed from unencapsulated drug) stored under the same conditions lost only 17% of its initial activity. The findings of this study, provide strong support for ampicillin-liposome formulations as valid dosage forms for this drug that are worthy of further experimental evaluations.

Ampicillin↗
PubMed1994

[Bacteria-reducing properties of copper-containing and non-copper-containing materials. II. Relationship between microbiocide effect of copper-containing materials and copper ion concentration after contamination with moist and dry hands].

The bactericide quality of different materials containing copper (copper, brass, brass-sheet) was tested and particularly the effect of humidity and copper-concentration was examined. In first examinations (I. communication) (19) the materials were contaminated by hands, which were dipped into a suspension of different microorganisms (Micrococcus luteus, Staphylococcus aureus, Enterococcus faecium, Escherichia coli, Enterobacter cloacae, Pseudomonas aeruginosa). The survival rate of the microorganisms on the surfaces was determined after defined exposure times (0, 5, 30, 60, 120 min). The following ways of contaminating the test materials were chosen: single contamination with wet hands, repeated contamination with wet and dry hands. In this examination the results were tested for statistical significance and in parallel experiments the copper-concentration on the surfaces of the materials was determined. Materials containing copper contaminated with wet hands show a significant bactericide effect after an exposure time of 120 min. The bactericide effect on Micrococcus luteus and Pseudomonas aeruginosa is inhibited after contamination with dry hands. This results can not be explained by a different copper-concentration on the surfaces of the materials, because a statistically significant difference of copper-ion concentrations between contamination with wet and dry hands could not be obtained.

Bacteria↗
PubMed1985

Subunit analysis of latent and non-latent F1-ATPase from Micrococcus lysodeikticus (luteus).

Limited trypsin and chymotrypsin digestions were performed on the latent F1-ATPase from M. lysodeikticus, and subsequent analysis on SDS-polyacrylamide gels revealed subunit profiles with degraded alpha and delta subunits similar to those of ATPase preparations with spontaneously occurring lower degrees of latency. The ATPase obtained from M. lysodeikticus membranes after n-butanol extraction was also non-latent with similar SDS-gel patterns to the aforementioned ATPases. In addition, the sensitive technique of crossed immunoelectrophoresis was used to show that all of the above ATPases contained alpha, beta, gamma, delta and epsilon subunits but some of them were in degraded forms. Although the delta subunit was the first to be cleaved, the loss of latency can be attributed to the degradation of the alpha subunit.

Butanols↗