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PloS One 2019Immune response and reproductive success are two vital energy-consuming processes in living organisms. However, it is still unclear which process is prioritized when...
Immune response and reproductive success are two vital energy-consuming processes in living organisms. However, it is still unclear which process is prioritized when both are required. Therefore, the present study was designed to examine this question arising for one of the world's most destructive agricultural pests, the migratory locust, Locusta migratoria. Transcripts from the ovaries and fat bodies of newly emerged locusts were analyzed, using RNA-seq based transcriptome and qualitative real-time PCR, at 4 h and 6 d after being infected with the gram-positive bacteria Micrococcus luteus. Changes in the main biological pathways involved in reproduction and immunization were analyzed using bioinformatics. After 4 h of infection, 348 and 133 transcripts were up- and down-regulated, respectively, whereas 5699 and 44 transcripts were up- and down-regulated, respectively, at 6 d after infection. Moreover, KEGG analysis indicated that vital pathways related with immunity and reproduction, such as Insulin resistance, FoxO signaling, Lysosome, mTOR signaling, and Toll-like receptor signaling pathways were up-regulated. Among the differentially expressed genes, 22 and 17 were related to immunity and reproduction, respectively. The expression levels of PPO1 and antimicrobial peptide defensin 3 were increased (log2FC = 5.93 and 6.75, respectively), whereas those of VgA and VgB were reduced (log2FC = -17.82 and -18.13, respectively). These results indicated that locust allocate energy and resources to maintain their own survival by increasing immune response when dealing with both immune and reproductive processes. The present study provides the first report of expression levels for genes related with reproduction and immunity in locusts, thereby providing a reference for future studies, as well as theoretical guidance for investigations of locust control.
Topics: Animals; Computational Biology; Gene Expression Regulation; Immunity, Innate; Insect Proteins; Locusta migratoria; Micrococcus luteus; Reproduction; Signal Transduction; Transcriptome
PubMed: 31412031
DOI: 10.1371/journal.pone.0211605 -
Clinical Characteristics of Patients with Bloodstream Infection in a Chinese Tertiary-Care Hospital.Polish Journal of Microbiology Sep 2021Few pieces of research have focused on bloodstream infection (BSI) because of its low incidence; hence data is needed to illustrate this uncommon infection. This study...
Few pieces of research have focused on bloodstream infection (BSI) because of its low incidence; hence data is needed to illustrate this uncommon infection. This study aimed to explore the clinical characteristics of patients with BSI. From January 2010 to December 2019, inpatients that met the criteria for BSI were included in this study. Data was collected by reviewing electronic records. Ninety-seven patients were enrolled in this study. Sixty-three percent of the patients have a higher neutrophil percentage (NEUT%). The average blood C-reactive protein (CRP) concentration was 5.5 ± 6.4 mg/dl. 48.5% of the patients had malignancy, and 40.2% underwent invasive surgeries. Linezolid was found to have the largest average diameter of the inhibition zone (36 mm), while erythromycin was found to have the smallest average zone diameter (15 mm). However, some strains had a potentially broad antimicrobial resistance spectrum. Cephalosporins (59.2%) and quinolones (21.4%) were the most commonly used antibiotics for empirical therapies. In conclusion, BSI mainly happens in immunocompromised patients or those with former invasive surgeries or indwelling catheters. strains are less responsive to erythromycin. Cephalosporins and quinolones are effective empirical antibiotics for BSI; however, vancomycin and teicoplanin should be considered for potentially broadly drug-resistant strains.
Topics: China; Gram-Positive Bacterial Infections; Humans; Micrococcus luteus; Sepsis; Tertiary Care Centers
PubMed: 34584526
DOI: 10.33073/pjm-2021-030 -
Genes Aug 2021Historically, was one of the first organisms used to study natural transformation, one of the main routes of horizontal gene transfer among prokaryotes. However, little...
Historically, was one of the first organisms used to study natural transformation, one of the main routes of horizontal gene transfer among prokaryotes. However, little is known about the molecular basis of competence development in or any other representative of the phylum of high-GC Gram-positive bacteria (Actinobacteria), while this means of genetic exchange has been studied in great detail in Gram-negative and low-GC Gram-positive bacteria (Firmicutes). In order to identify new genetic elements involved in regulation of the - competence operon in , we conducted random chemical mutagenesis of a reporter strain expressing under the control of the - promoter, followed by the screening of dysregulated mutants. Mutants with (i) upregulated promoter under competence-repressing conditions and (ii) mutants with a repressed promoter under competence-inducing conditions were isolated. After genotype and phenotype screening, the genomes of several mutant strains were sequenced. A selection of putative -influencing mutations was reinserted into the genome of the reporter strain as markerless single-nucleotide mutations to confirm their effect on gene expression. This strategy revealed mutations affecting gene expression at genetic loci different from previously known genes involved in natural transformation. Several of these mutations decreased transformation frequencies by several orders of magnitude, thus indicating significant roles in competence development or DNA acquisition in . Among the identified loci, there was a new locus containing genes with similarity to genes of the clusters of and other bacteria
Topics: Chromosomes, Bacterial; DNA, Bacterial; Gene Expression Regulation, Bacterial; Gene Transfer, Horizontal; Genetic Loci; Micrococcus luteus; Mutagenesis; Promoter Regions, Genetic; Transformation, Bacterial
PubMed: 34573289
DOI: 10.3390/genes12091307 -
Scientific Reports Oct 2021In recent years' synthesis of metal nanoparticle using plants has been extensively studied and recognized as a non-toxic and efficient method applicable in biomedical...
In recent years' synthesis of metal nanoparticle using plants has been extensively studied and recognized as a non-toxic and efficient method applicable in biomedical field. The aim of this study is to investigate the role of different parts of medical plant Carduus crispus on synthesizing silver nanoparticles and characterize the produced nanoparticle. Our study showed that silver nanoparticles (AgNP) synthesized via whole plant extract exhibited a blue shift in absorption spectra with increased optical density, which correlates to a high yield and small size. Also, the results of zeta potential, X-ray diffraction, photon cross-correlation spectroscopy analysis showed the surface charge of - 54.29 ± 4.96 mV (AgNP-S), - 42.64 ± 3.762 mV (AgNP-F), - 46.02 ± 4.17 mV (AgNP-W), the crystallite size of 36 nm (AgNP-S), 13 nm (AgNP-F), 14 nm (AgNP-W) with face-centered cubic structure and average grain sizes of 145.1 nm, 22.5 nm and 99.6 nm. Another important characteristic, such as elemental composition and constituent capping agent has been determined by energy-dispersive X-ray spectroscopy and Fourier transform infrared. The silver nanoparticles were composed of ~ 80% Ag, ~ 15% K, and ~ 7.5% Ca (or ~ 2.8% P) elements. Moreover, the results of the FTIR measurement suggested that the distinct functional groups present in both AgNP-S and AgNP-F were found in AgNP-W. The atomic force microscopy analysis revealed that AgNP-S, AgNP-F and AgNP-W had sizes of 131 nm, 33 nm and 70 nm respectively. In addition, the biosynthesized silver nanoparticles were evaluated for their cytotoxicity and antibacterial activity. At 17 µg/ml concentration, AgNP-S, AgNP-F and AgNP-W showed very low toxicity on HepG2 cell line but also high antibacterial activity. The silver nanoparticles showed antibacterial activity on both gram-negative bacterium Escherichia coli (5.5 ± 0.2 mm to 6.5 ± 0.3 mm) and gram-positive bacterium Micrococcus luteus (7 ± 0.4 mm to 7.7 ± 0.5 mm). Our study is meaningful as a first observation indicating the possibility of using special plant organs to control the characteristics of nanoparticles.
Topics: Anti-Bacterial Agents; Carduus; Escherichia coli; Hep G2 Cells; Humans; Metal Nanoparticles; Micrococcus luteus; Silver
PubMed: 34702916
DOI: 10.1038/s41598-021-00520-2 -
Journal of Medical Case Reports Jun 2011Micrococcus luteus endocarditis is a rare case of infective endocarditis. A total of 17 cases of infective endocarditis due to M luteus have been reported in the...
INTRODUCTION
Micrococcus luteus endocarditis is a rare case of infective endocarditis. A total of 17 cases of infective endocarditis due to M luteus have been reported in the literature to date, all involving prosthetic valves. To the best of our knowledge, we describe the first case of native aortic valve M luteus endocarditis in an immunosuppressed patient in this report.
CASE REPORT
A 74-year-old Greek-Cypriot woman was admitted to our Internal Medicine Clinic due to fever and malaise and the diagnosis of aortic valve M luteus endocarditis was made. She was immunosuppressed due to methotrexate and steroid treatment. Our patient was unsuccessfully treated with vancomycin, gentamicin and rifampicin for four weeks. The aortic valve was replaced and she was discharged in good condition.
CONCLUSIONS
Prosthetic infective endocarditis due to M luteus is rare. To the best of our knowledge, we report the first case in the literature involving a native valve.
PubMed: 21714882
DOI: 10.1186/1752-1947-5-251 -
ACS Applied Materials & Interfaces May 2020Biofilm formation is most commonly combatted with antibiotics or biocides. However, proven toxicity and increasing resistance of bacteria increase the need for...
Biofilm formation is most commonly combatted with antibiotics or biocides. However, proven toxicity and increasing resistance of bacteria increase the need for alternative strategies to prevent adhesion of bacteria to surfaces. Chemical modification of the surfaces by tethering of functional polymer brushes or films provides a route toward antifouling coatings. Furthermore, nanorough or superhydrophobic surfaces can delay biofilm formation. Here we show that submicrometer-sized roughness can outweigh surface chemistry by testing the adhesion of to surfaces of different topography and wettability over long exposure times (>7 days). Gram-negative and positive bacterial strains are tested for comparison. We show that an irregular three-dimensional layer of silicone nanofilaments suppresses bacterial adhesion, both in the presence and absence of an air cushion. We hypothesize that a 3D topography can delay biofilm formation (i) if bacteria do not fit into the pores of the coating or (ii) if bending of the bacteria is required to adhere. Thus, such a 3D topography offers an underestimated possibility to design antibacterial surfaces that do not require biocides or antibiotics.
Topics: Bacterial Adhesion; Biofouling; Escherichia coli; Glass; Hydrocarbons, Fluorinated; Micrococcus luteus; Nanostructures; Pseudomonas fluorescens; Silicones; Wettability
PubMed: 32142252
DOI: 10.1021/acsami.9b22621 -
Biotechnology For Biofuels 2020The natural production of olefins (unsaturated aliphatic hydrocarbons) by certain bacterial genera represents an alternative and sustainable source of biofuels and...
BACKGROUND
The natural production of olefins (unsaturated aliphatic hydrocarbons) by certain bacterial genera represents an alternative and sustainable source of biofuels and lubricant components. The biochemical steps of olefin biosynthesis via the ole pathway encoded by have been unraveled recently, and the occurrence of olefins has been reported for several Gram-negative and Gram-positive bacteria. However, the distribution and diversity of olefins among the Gram-positive bacteria has not been studied in detail.
RESULTS
We report the distribution of olefin synthesis gene clusters in the bacterial domain and focus on the olefin composition and the determinants of olefin production within the phylum of . The olefin profiles of numerous genera of the order were analyzed by GC/MS. We describe for the first time olefin synthesis in representatives of the genera , , , , , , , , and . By exchange of the native genes of with the corresponding genes of actinobacteria producing different olefins, we demonstrate that the olefin composition can be manipulated with respect to chain length and isomer composition.
CONCLUSIONS
This study provides a catalogue of the diversity of olefin structures found in the Our gene swapping data indicate that the olefin structures are fundamentally determined by the substrate specificity of OleA, and at the same time by the availability of a sufficient supply of suitable fatty acyl-CoA substrates from cellular fatty acid metabolism. This makes OleA of Gram-positive bacteria a promising target for structural analysis and protein engineering aiming to generate olefin chain lengths and isomer profiles which are designed to match the requirements of various industrial applications.
PubMed: 32313552
DOI: 10.1186/s13068-020-01706-y -
Molecules (Basel, Switzerland) Nov 2022The growing problem of antibiotic resistance among bacteria requires searching for new therapeutic agents with bacteriostatic and/or bactericidal properties. Crotoxin is...
The growing problem of antibiotic resistance among bacteria requires searching for new therapeutic agents with bacteriostatic and/or bactericidal properties. Crotoxin is a β-neurotoxin from the venom of the It is composed of two subunits: CA (non-active) and CB (with phospholipase A activity). It has already been shown that the isolated CB, but not the CA, subunit of crotoxin exhibits an antibacterial activity towards a variety of Gram-positive and Gram-negative bacterial species. However, no studies on the whole crotoxin complex have been carried out so far. We tested the antibacterial properties of crotoxin, as well as its isolated CB subunit, towards ATCC 25923, ATCC 6535, ATCC 10240, ATCC 25922, ATCC 8739, and ATCC 10145. Both toxins exhibited antibacterial properties only against ATCC 10240. Crotoxin showed only bacteriostatic activity with a MIC of 46 µM, while the CB subunit acted as both a bacteriostatic and bactericidal agent with a MIC = MBC = 0.21 μM. The bacteriostatic effect of the toxins was independent of the enzymatic activity of the CB subunit. Bactericidal properties, however, require phospholipase A activity. Both toxins reduced bacteria viability at the MIC by 72% and 85% for crotoxin- and CB-treated bacteria, respectively. The membrane permeability increased approximately three times within the first hour of incubation with toxins; afterwards, either no significant changes or a decrease of membrane permeability, compared to the control cells, were observed. We isolated a single, approximately 30 kDa bacterial wall protein which belongs to the NlpC/P60 family that interacts with crotoxin leading to the inhibition of bacterial growth. Neither crotoxin nor the CB subunit showed any cytotoxic properties to human fibroblasts at the MIC during the three-day incubation.
Topics: Animals; Humans; Crotoxin; Crotalus; Phospholipases A2; Anti-Bacterial Agents; Escherichia coli
PubMed: 36431827
DOI: 10.3390/molecules27227726 -
Journal of Bacteriology Jul 2017Dormancy is a protective state in which diverse bacteria, including , , (syphilis), and (Lyme disease), curtail metabolic activity to survive external stresses,...
Dormancy is a protective state in which diverse bacteria, including , , (syphilis), and (Lyme disease), curtail metabolic activity to survive external stresses, including antibiotics. Evidence suggests dormancy consists of a continuum of interrelated states, including viable but nonculturable (VBNC) and persistence states. VBNC and persistence contribute to antibiotic tolerance, reemergence from latent infections, and even quorum sensing and biofilm formation. Previous studies indicate that the protein mechanisms regulating persistence and VBNC states are not well understood. We have queried the VBNC state of NCTC 2665 (MI-2665) by quantitative proteomics combining gel electrophoresis, high-performance liquid chromatography, and tandem mass spectrometry to elucidate some of these mechanisms. MI-2665 is a nonpathogenic actinobacterium containing a small (2.5-Mb), high-GC-content genome which exhibits a well-defined VBNC state induced by nutrient deprivation. The MI-2665 VBNC state demonstrated a loss of protein diversity accompanied by increased levels of 18 proteins that are conserved across actinobacteria, 14 of which have not been previously identified in VNBC. These proteins implicate an anaplerotic strategy in the transition to VBNC, including changes in the glyoxylate shunt, redox and amino acid metabolism, and ribosomal regulatory processes. Our data suggest that MI-2665 is a viable model for dissecting the protein mechanisms underlying the VBNC stress response and provide the first protein-level signature of this state. We expect that this protein signature will enable future studies deciphering the protein mechanisms of dormancy and identify novel therapeutic strategies effective against antibiotic-tolerant bacterial infections. Dormancy is a protective state enabling bacteria to survive antibiotics, starvation, and the immune system. Dormancy is comprised of different states, including persistent and viable but nonculturable (VBNC) states that contribute to the spread of bacterial infections. Therefore, it is imperative to identify how bacteria utilize these different dormancy states to survive antibiotic treatment. The objective of our research is to eliminate dormancy as a route to antibiotic tolerance by understanding the proteins that control dormancy in NCTC 2665. This bacterium has unique advantages for studying dormancy, including a small genome and a well-defined and reproducible VBNC state. Our experiments implicate four previously identified and 14 novel proteins upregulated in VBNC that may regulate this critical survival mechanism.
Topics: Bacterial Proteins; Bacteriological Techniques; Gene Expression Regulation, Bacterial; Micrococcus luteus; Proteomics; Stress, Physiological
PubMed: 28484042
DOI: 10.1128/JB.00206-17 -
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