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Journal of Biochemistry Jul 1985The 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...
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.
Topics: Carbohydrate Dehydrogenases; Isomerism; Kinetics; Micrococcus; NAD; Uridine Diphosphate Sugars
PubMed: 4044544
DOI: 10.1093/oxfordjournals.jbchem.a135248 -
Scientific Reports Jul 2019Natural competence for genetic transformation refers to the natural ability of various bacteria to take up exogenous DNA from their surroundings and to incorporate...
Natural competence for genetic transformation refers to the natural ability of various bacteria to take up exogenous DNA from their surroundings and to incorporate internalized genetic information into their genomes. By promoting bacterial diversification and adaptability, this process represents a major driving force in bacterial evolution. Micrococcus luteus was one of the first organisms used to study natural transformation in bacteria. Since then, however, only very little information about this phenomenon has been reported in M. luteus or in any member of the Actinobacteria phylum (low-GC Gram-positive bacteria). Previous work in our group indicated major differences between the transformation apparatus of M. luteus and the transformation machinery described for various Gram-negative and Gram-positive model bacteria belonging to the phyla Proteobacteria and Firmicutes (high-GC Gram-positive bacteria). This prompted us to initiate a study concerning the regulation mechanism of competence development in M. luteus. In this report, we identify amino acids as a nutritional factor that influences competence in a concentration-dependent manner. By using a transcriptional reporter strain for one of the late competence genes, we demonstrate how increasing concentrations of both amino acids mixtures and single amino acids supplemented to the growth medium affect transformability on transcriptional and post-transcriptional level. Furthermore, we revisit previously generated auxotrophic mutants to show that the transformation machinery is turned down during a state of extreme hunger for amino acids presumably as a part of a general response to auxotrophy. Finally, by generating and analysing knockout mutants for two predicted stringent response enzymes, we provide evidence for the involvement of the alarmone (p)ppGpp as a putative mediator of the effects on transformation development caused by amino acids. As a member of the Actinobacteria phylum, M. luteus could serve as a model for other representatives of the phylum, including a number of important human pathogens.
Topics: Amino Acids; Gene Expression Regulation, Bacterial; Guanosine Pentaphosphate; Guanosine Tetraphosphate; Micrococcus luteus; Transformation, Genetic
PubMed: 31363120
DOI: 10.1038/s41598-019-47423-x -
Journal of Bacteriology Nov 2010We report the cloning and characterization of the biosynthetic gene cluster (crtE, crtB, crtI, crtE2, crtYg, crtYh, and crtX) of the γ-cyclic C(50) carotenoid...
Biosynthetic pathway for γ-cyclic sarcinaxanthin in Micrococcus luteus: heterologous expression and evidence for diverse and multiple catalytic functions of C(50) carotenoid cyclases.
We report the cloning and characterization of the biosynthetic gene cluster (crtE, crtB, crtI, crtE2, crtYg, crtYh, and crtX) of the γ-cyclic C(50) carotenoid sarcinaxanthin in Micrococcus luteus NCTC2665. Expression of the complete and partial gene cluster in Escherichia coli hosts revealed that sarcinaxanthin biosynthesis from the precursor molecule farnesyl pyrophosphate (FPP) proceeds via C(40) lycopene, C(45) nonaflavuxanthin, C(50) flavuxanthin, and C(50) sarcinaxanthin. Glucosylation of sarcinaxanthin was accomplished by the crtX gene product. This is the first report describing the biosynthetic pathway of a γ-cyclic C(50) carotenoid. Expression of the corresponding genes from the marine M. luteus isolate Otnes7 in a lycopene-producing E. coli host resulted in the production of up to 2.5 mg/g cell dry weight sarcinaxanthin in shake flasks. In an attempt to experimentally understand the specific difference between the biosynthetic pathways of sarcinaxanthin and the structurally related ε-cyclic decaprenoxanthin, we constructed a hybrid gene cluster with the γ-cyclic C(50) carotenoid cyclase genes crtYg and crtYh from M. luteus replaced with the analogous ε-cyclic C(50) carotenoid cyclase genes crtYe and crtYf from the natural decaprenoxanthin producer Corynebacterium glutamicum. Surprisingly, expression of this hybrid gene cluster in an E. coli host resulted in accumulation of not only decaprenoxanthin, but also sarcinaxanthin and the asymmetric ε- and γ-cyclic C(50) carotenoid sarprenoxanthin, described for the first time in this work. Together, these data contributed to new insight into the diverse and multiple functions of bacterial C(50) carotenoid cyclases as key catalysts for the synthesis of structurally different carotenoids.
Topics: Bacterial Proteins; Carotenoids; Cloning, Molecular; Escherichia coli; Gene Expression Regulation, Bacterial; Glycosyltransferases; Micrococcus luteus; Molecular Structure; Multigene Family; Xanthophylls
PubMed: 20802040
DOI: 10.1128/JB.00724-10 -
Microorganisms Apr 2021Although malodour formation on textiles and in washing machines has been reported to be a very relevant problem in domestic laundry, the processes leading to bad odours...
Although malodour formation on textiles and in washing machines has been reported to be a very relevant problem in domestic laundry, the processes leading to bad odours have not been studied intensively. In particular, the smell often described as "wet-and-dirty-dustcloth-like malodour" had not been reproduced previously. We developed a lab model based on a bacterial mixture of , , and , which can produce this odour type and which might allow the detailed investigation of this problem and the development of counteractions. The model uses bacterial strains that have been isolated from malodourous textiles. We could also show that the three volatile compounds dimethyl disulfide, dimethyl trisulfide, and indole contribute considerably to the "wet-fabric-like" malodour. These substances were not only found to be formed in the malodour model but have already been identified in the literature as relevant malodourous substances.
PubMed: 33946384
DOI: 10.3390/microorganisms9050974 -
Journal of Food Protection Dec 2007Because of increased concerns over failures in cleaning, the role of bioaerosols, and the environmental and clinical persistence of pathogens, the evaluation of novel...
Because of increased concerns over failures in cleaning, the role of bioaerosols, and the environmental and clinical persistence of pathogens, the evaluation of novel decontaminants is increasingly important. The bactericidal properties of open air factor (OAF; a collection of highly reactive chemical species) were identified in the 1970s; however, the potential practical applications of artificially generated OAF have been considered only recently. In this study, the effects of OAF against Micrococcus luteus were investigated. OAF was generated and distributed in a bioaerosol test chamber by delivery of monoterpenes into ozonated air (0.1 ppm) at concentrations of 2.0 (high), 0.75 (medium), or 0.3 (low) mgm(-3) h(-1). M. luteus was aerosolized, and the number of culturable survivors was determined after 2, 5, 10, 20, and 60 min. Culturable bacteria were enumerated by aerobic plate counts in all-glass impinger fluid. Data were analyzed for statistical significance using one- or two-way analyses of variance. When aerosolized bacteria were exposed to ozone alone (0.05, 0.1, and 2 ppm), a significant (up to 3-log) reduction was observed at all concentrations, and the effect was time dependent. When exposed to the cyclic monoterpene alone, there were no significant differences between test samples and controls. When exposed to OAF (high and medium concentrations in 0.1 ppm ozone) there were significant differences after 20 min. These reductions were significantly greater than those achieved with ozone alone at 0.1 ppm. OAF is potentially an effective antibacterial agent that can reduce the microbial load in air. Because the technology uses reaction compounds naturally found in the environment, risks to health may be lower than those associated with ozone or other gaseous treatments. However, this hypothesis needs further investigation.
Topics: Air Microbiology; Analysis of Variance; Colony Count, Microbial; Dose-Response Relationship, Drug; Food Contamination; Micrococcus luteus; Monoterpenes; Oxidants, Photochemical; Ozone; Time Factors
PubMed: 18095429
DOI: 10.4315/0362-028x-70.12.2769 -
Frontiers in Microbiology 2015Natural transformation has been described in bacterial species spread through nearly all major taxonomic groups. However, the current understanding of the structural...
Natural transformation has been described in bacterial species spread through nearly all major taxonomic groups. However, the current understanding of the structural components and the regulation of competence development is derived from only a few model organisms. Although natural transformation was discovered in members of the Actinobacteria (high GC Gram-positive bacteria) more than four decades ago, the structural components or the regulation of the competence system have not been studied in any representative of the entire phylum. In this report we identify a new role for a distinct type of pilus biogenesis genes (tad genes, for tight adherence), which so far have been connected only with biofilm formation, adherence and virulence traits. The tad-like genes found in the genome of Micrococcus luteus were shown to be required for genetic transformation in this actinobacterial species. We generated and analyzed individual knockout mutants for every open reading frame of the two predicted tad gene clusters as well as for a potential prepilin processing peptidase and identified the major component of the putative pili. By expressing a tagged variant of the major prepilin subunit and immunofluorescence microscopy we visualized filamentous structures extending from the cell surface. Our data indicate that the two tad gene islands complementarily contribute to the formation of a functional competence pilus in this organism. It seems likely that the involvement of tad genes in natural transformation is not unique only for M. luteus but may also prove to be the case in other representatives of the Actinobacteria, which contains important medically and biotechnologically relevant species.
PubMed: 25713572
DOI: 10.3389/fmicb.2015.00084 -
Frontiers in Microbiology 2022The importance of the impact of human hormones on commensal microbiota and microbial biofilms is established in lots of studies. In the present investigation, we...
The importance of the impact of human hormones on commensal microbiota and microbial biofilms is established in lots of studies. In the present investigation, we continued and extended the research of epinephrine effects on the skin commensal C01 and its biofilms, and also the matrix changes during the biofilm growth. Epinephrine in concentration 4.9 × 10 M which is close to normal blood plasma level increased the amount of polysaccharides and extracellular DNA in the matrix, changed extensively its protein, lipid and polysaccharide composition. The Ef-Tu factor was one of the most abundant proteins in the matrix and its amount increased in the presence of the hormone. One of the glucose-mannose polysaccharide was absent in the matrix in presence of epinephrine after 24 h of incubation. The matrix phospholipids were also eradicated by the addition of the hormone. Hence, epinephrine has a great impact on the biofilms and their matrix composition, and this fact opens wide perspectives for the future research.
PubMed: 36204611
DOI: 10.3389/fmicb.2022.1003942 -
World Journal of Clinical Cases Sep 2023()-induced endophthalmitis is very rare and and may present as either acute or chronic postoperative endophthalmitis. The aim of this study was to report a case of...
BACKGROUND
()-induced endophthalmitis is very rare and and may present as either acute or chronic postoperative endophthalmitis. The aim of this study was to report a case of delayed-onset -induced endophthalmitis that occurred several months after cataract surgery.
CASE SUMMARY
A 78-year-old man presented with decreased vision, pain and redness in the right eye that had begun 3 days prior. He had undergone cataract surgery 4 mo prior. Visual acuity was counting fingers; slit-lamp examination revealed conjunctival injection, posterior corneal precipitates, anterior chamber inflammation (cell 4+), and hypopyon. Fundus examination revealed moderate vitreous haze. Urgent vitrectomy was performed for suspected infectious endophthalmitis, followed by vitreous irrigation with injections of antibiotics. On the postoperative day 1, anterior chamber cell decreased to 2+ and hypopyon was not observed on slit lamp examination. Six days postoperatively, the patient had recurrent eye pain, and the anterior chamber cell grade increased to 4+; hypopyon recurred in the anterior chamber, and whitish plaque was observed in the lens capsule. Therefore, the patient underwent intraocular lens (IOL) and lens capsule removal, followed by vitreous irrigation, antibiotics injection, and vitrectomy. was identified from a lens capsule culture.
CONCLUSION
In cases of delayed-onset -induced endophthalmitis, early vitrectomy and removal of the IOL and lens capsule may be necessary.
PubMed: 37900232
DOI: 10.12998/wjcc.v11.i27.6592 -
Genomics Data Sep 2016Micrococcus luteus is a predominant member of skin microbiome. We here report on the genomic analysis of Micrococcus luteus strain O'Kane that was isolated from an...
Micrococcus luteus is a predominant member of skin microbiome. We here report on the genomic analysis of Micrococcus luteus strain O'Kane that was isolated from an elevator. The partial genome assembly of Micrococcus luteus strain O'Kane is 2.5 Mb with 2256 protein-coding genes and 62 RNA genes. Genomic analysis revealed metabolic versatility with genes involved in the metabolism and transport of glucose, galactose, fructose, mannose, alanine, aspartate, asparagine, glutamate, glutamine, glycine, serine, cysteine, methionine, arginine, proline, histidine, phenylalanine, and fatty acids. Genomic comparison to other M. luteus representatives identified the potential to degrade polyhydroxybutyrates, as well as several antibiotic resistance genes absent from other genomes.
PubMed: 27583205
DOI: 10.1016/j.gdata.2016.08.006 -
Applied and Environmental Microbiology Jul 2018Only a small fraction of bacteria can autonomously initiate growth on agar plates. Nongrowing bacteria typically enter a metabolically inactive dormant state and require...
Only a small fraction of bacteria can autonomously initiate growth on agar plates. Nongrowing bacteria typically enter a metabolically inactive dormant state and require specific chemical trigger factors or signals to exit this state and to resume growth. has become a model organism for this important yet poorly understood phenomenon. Only a few resuscitation signals have been described to date, and all of them are produced endogenously by bacterial species. We report the discovery of a novel type of resuscitation signal that allows to grow on agar but not agarose plates. Fractionation of the agar polysaccharide complex and sulfation of agarose allowed us to identify the signal as highly sulfated saccharides found in agar or carrageenans. Purification of hydrolyzed κ-carrageenan ultimately led to the identification of the signal as a small fragment of a large linear polysaccharide, i.e., an oligosaccharide of five or more sugars with a repeating disaccharide motif containing d-galactose-4-sulfate (G4S) 1,4-linked to 3,6-anhydro-α-d-galactose (DA), G4S-(DA-G4S) Most environmental bacteria cannot initiate growth on agar plates, but they can flourish on the same plates once growth is initiated. While there are a number of names for and manifestations of this phenomenon, the underlying cause appears to be the requirement for a molecular signal indicating safe growing conditions. has become a model organism for studying this growth initiation process, often called resuscitation, because of its apparent connection with the persistent or dormant form of , an important human pathogen. In this report, we identify a highly sulfated saccharide from agar or carrageenans that robustly resuscitates dormant on agarose plates. We identified and characterized the signal as a small repeating disaccharide motif. Our results indicate that signals inherent in or absent from the polysaccharide composition of solid growth media can have major effects on bacterial growth.
Topics: Agar; Carrageenan; Culture Media; Galactans; Micrococcus luteus; Polysaccharides; Sulfates
PubMed: 29678921
DOI: 10.1128/AEM.00745-18