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1.
Chinese Journal of Biotechnology ; (12): 2379-2392, 2021.
Article in Chinese | WPRIM | ID: wpr-887804

ABSTRACT

TetR family transcriptional regulators (TFRs) are widely distributed in bacteria and archaea, and the first discovered TFR was confirmed to control the expression of tetracycline efflux pump in Escherichia coli. TFRs can bind DNAs and ligands. Small molecule ligands can induce conformational changes of TFRs, inhibiting or promoting TFRs to control target gene expression. Currently, TFRs have a wide variety of ligands, including carbohydrates, proteins, fatty acids and their derivatives, metal ions, and so on. Due to the diversity of ligands, TFRs regulate a wide range of physiological processes, from basic carbon metabolism and nitrogen metabolism to quorum sensing and antibiotic biosynthesis. On the basis of the recent studies in our laboratory and the literature, we review here the regulatory mechanism mediated by ligands of TFRs in primary and secondary metabolism, as well as the application of ligands for TFRs in the development of gene route and the activation of antibiotic biosynthesis.


Subject(s)
Anti-Bacterial Agents , Bacteria/metabolism , Bacterial Proteins/metabolism , Gene Expression Regulation, Bacterial , Ligands , Quorum Sensing
2.
Article in English | WPRIM | ID: wpr-878362

ABSTRACT

Objective@#To investigate reciprocal regulation between Fur and two RyhB homologs in @*Methods@#Regulatory relationships were assessed by a combination of colony morphology assay, primer extension, electrophoretic mobility shift assay and DNase I footprinting.@*Results@#Fur bound to the promoter-proximal DNA regions of @*Conclusion@#Fur and the two RyhB homologs exert negative reciprocal regulation, and RyhB homologs have a positive regulatory effect on biofilm formation in


Subject(s)
Bacterial Proteins/metabolism , Biofilms , Gene Expression Regulation, Bacterial/physiology , Yersinia pestis/physiology
3.
Article in English | WPRIM | ID: wpr-880483

ABSTRACT

Protein lysine methylation is a prevalent post-translational modification (PTM) and plays critical roles in all domains of life. However, its extent and function in photosynthetic organisms are still largely unknown. Cyanobacteria are a large group of prokaryotes that carry out oxygenic photosynthesis and are applied extensively in studies of photosynthetic mechanisms and environmental adaptation. Here we integrated propionylation of monomethylated proteins, enrichment of the modified peptides, and mass spectrometry (MS) analysis to identify monomethylated proteins in Synechocystis sp. PCC 6803 (Synechocystis). Overall, we identified 376 monomethylation sites in 270 proteins, with numerous monomethylated proteins participating in photosynthesis and carbon metabolism. We subsequently demonstrated that CpcM, a previously identified asparagine methyltransferase in Synechocystis, could catalyze lysine monomethylation of the potential aspartate aminotransferase Sll0480 both in vivo and in vitro and regulate the enzyme activity of Sll0480. The loss of CpcM led to decreases in the maximum quantum yield in primary photosystem II (PSII) and the efficiency of energy transfer during the photosynthetic reaction in Synechocystis. We report the first lysine monomethylome in a photosynthetic organism and present a critical database for functional analyses of monomethylation in cyanobacteria. The large number of monomethylated proteins and the identification of CpcM as the lysine methyltransferase in cyanobacteria suggest that reversible methylation may influence the metabolic process and photosynthesis in both cyanobacteria and plants.


Subject(s)
Bacterial Proteins/metabolism , Lysine/metabolism , Methyltransferases/metabolism , Photosynthesis , Protein Processing, Post-Translational , Synechocystis/growth & development
4.
Rev. bras. enferm ; 72(3): 760-766, May.-Jun. 2019. tab
Article in English | LILACS, BDENF | ID: biblio-1013564

ABSTRACT

ABSTRACT Objective: To evaluate the risk factors related to Klebsiella pneumoniae carbapenemase infection after renal transplantation. Methods: This was a retrospective epidemiological (case-control) study, conducted from October 2011 to march 2016. Transplanted patients with infection by this bacteria during hospitalization were selected as cases. The controls were paired by age, sex, type of donor and transplant time. The proportion of cases and controls was 1:2. Results: Thirty hundred and five patients were included in the study (45 cases and 90 controls). The risk factors found for infection by KPC were: time of hospitalization after the transplant (OR: 4.82; CI95% 2.46-9.44), delayed kidney function (OR: 5.60; CI95% 1.91-11.01) and previous infectious for another microorganism ( OR: 34.13 CI95% 3.52-132.00). Conclusion: The risk of acquisition of this bacterium was directly related to invasive procedures and exposure to the hospital environment. The findings reinforce the importance of prevention measures and control of infection by this microorganism.


RESUMEN Objetivo: Evaluar los factores de riesgo relacionados con la infección por Klebsiella pneumoniae carbapenemasa después del trasplante renal. Método: Estudio retrospectivo epidemiológico (caso-control), realizado de octubre de 2011 a marzo de 2016. Pacientes transplantados con infección por esa bacteria durante la internación fueron seleccionados como casos. Los controles se parearon por edad, sexo, tipo de donante y tiempo de trasplante. La proporción de casos y controles fue de 1: 2. Resultados: Treinta y cinco pacientes fueron incluidos en el estudio (45 casos y 90 controles). Los factores de riesgo para la infección encontrados por KPC fueron: tiempo de hospitalización después del trasplante (OR: 4,82, IC95% 2,46-9,44), función renal retardada (OR: 5,60, IC95% 1, 91-11,01) y anterior infecciosa para otro microorganismo (OR: 34,13 IC95% 3,52-132,00). Conclusión: El riesgo de adquisición de esta bacteria estuvo directamente relacionado a procedimientos invasivos y exposición al ambiente hospitalario. Los hallazgos refuerzan la importancia de medidas de prevención y control de la infección por ese microorganismo.


Subject(s)
Humans , Male , Female , Adult , Pneumonia/ethnology , Bacterial Proteins/adverse effects , beta-Lactamases/adverse effects , Klebsiella Infections/etiology , Kidney Transplantation/adverse effects , Pneumonia/chemically induced , Pneumonia/epidemiology , Bacterial Proteins/metabolism , beta-Lactamases/metabolism , Brazil/epidemiology , Klebsiella Infections/metabolism , Klebsiella Infections/epidemiology , Case-Control Studies , Retrospective Studies , Risk Factors , Kidney Transplantation/methods , Klebsiella pneumoniae/metabolism , Klebsiella pneumoniae/pathogenicity , Middle Aged
5.
Braz. j. microbiol ; 49(4): 914-918, Oct.-Dec. 2018. tab
Article in English | LILACS | ID: biblio-974286

ABSTRACT

ABSTRACT The global emergence of carbapenemases led to the need of developing new methods for their rapid detection. The aim of this study was to evaluate the performance of the rapid tests for carbapenemase-producing and non-producing Enterobacteriaceae. Carbapenem non-susceptible Enterobacteriaceae from a surveillance study submitted to a multiplex real time PCR for carbapenemase detection were included in this study. The isolates were subjected to the rapid phenotypic tests Carba NP, Blue-Carba and Carbapenem Inactivation Method (CIM). A total of 83 carbapenemase-producing (43) and non-producing (40) isolates were included in the study. The sensitivity/specificity were 62.7%/97.5%, 95.3%/100%, and 74.4%/97.5% for Carba NP, Blue-Carba and CIM, respectively. Both Carba NP and Blue-Carba presented their final results after 75 min of incubation; the final results for CIM were obtained only after 8 h. Failure to detect OXA-370 carbapenemase was the main problem for Carba NP and CIM assays. As the Blue-Carba presented the highest sensitivity, it can be considered the best screening test. Conversely, CIM might be the easiest to perform, as it does not require special reagents. The early detection of carbapenemases aids to establish infection control measures and prevent carbapenemases to spread reducing the risk of healthcare associated infections and therapeutic failure.


Subject(s)
Humans , Bacterial Proteins/analysis , beta-Lactamases/analysis , Enterobacteriaceae/enzymology , Enterobacteriaceae Infections/microbiology , Enzyme Assays/methods , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , beta-Lactamases/genetics , beta-Lactamases/metabolism , Brazil , Carbapenems/pharmacology , Polymerase Chain Reaction , Sensitivity and Specificity , Enterobacteriaceae/isolation & purification , Enterobacteriaceae/drug effects , Enterobacteriaceae/genetics , Enterobacteriaceae Infections/diagnosis , Anti-Bacterial Agents/pharmacology
6.
Braz. j. microbiol ; 49(4): 731-741, Oct.-Dec. 2018. tab, graf
Article in English | LILACS | ID: biblio-974291

ABSTRACT

ABSTRACT A bacterium isolated from Sterkfontein dam was confirmed to produce bioflocculant with excellent flocculation activity. The 16S rDNA nucleotide sequence analyses revealed the bacteria to have 99% similarity to Streptomyces platensis strain HBUM174787 and the sequence was deposited in the Genbank as Streptomyces platensis with accession number FJ 486385.1. Culture conditions for optimal production of the bioflocculant included glucose as a sole carbon source, resulting in flocculating activity of 90%. Other optimal conditions included: peptone as nitrogen source; presence of Mg2+ as cations and inoculum size of 1.0% (v/v) at neutral pH of 7. Optimum dose of the purified bioflocculant for the clarification of 4 g/L kaolin clay suspension at neutral pH was 0.2 mg/mL. Energy Dispersive X-ray analysis confirmed elemental composition of the purified bioflocculant in mass proportion (%w/w): carbon (21.41), oxygen (35.59), sulphur (26.16), nitrogen (0.62) and potassium (7.48). Fourier Transform Infrared Spectroscopy (FTIR) indicated the presence of hydroxyl, carboxyl, methoxyl and amino group in the bioflocculant. The bioflocculant produced by S. platensis removed chemical oxygen demand (COD) in river water and meat processing wastewater at efficiencies of 63.1 and 46.6% respectively and reduced their turbidity by 84.3 and 75.6% respectively. The high flocculating rate and removal efficiencies displayed by S. platensis suggests its industrial application in wastewater treatment.


Subject(s)
Streptomyces/chemistry , Bacterial Proteins/metabolism , Waste Water/chemistry , Streptomyces/isolation & purification , Streptomyces/genetics , Streptomyces/metabolism , Bacterial Proteins/genetics , Water Microbiology , Carbon/metabolism , Water Purification , Rivers/chemistry , Flocculation , Nitrogen/metabolism
7.
Braz. j. microbiol ; 49(4): 848-855, Oct.-Dec. 2018. tab, graf
Article in English | LILACS | ID: biblio-974300

ABSTRACT

ABSTRACT We studied the role of Thermus thermophilus Recombinase A (RecA) in enhancing the PCR signals of DNA viruses such as Hepatitis B virus (HBV). The RecA gene of a thermophilic eubacterial strain, T. thermophilus, was cloned and hyperexpressed in Escherichia coli. The recombinant RecA protein was purified using a single heat treatment step without the use of any chromatography steps, and the purified protein (>95%) was found to be active. The purified RecA could enhance the polymerase chain reaction (PCR) signals of HBV and improve the detection limit of the HBV diagnosis by real time PCR. The yield of recombinant RecA was ∼35 mg/L, the highest yield reported for a recombinant RecA to date. RecA can be successfully employed to enhance detection sensitivity for the diagnosis of DNA viruses such as HBV, and this methodology could be particularly useful for clinical samples with HBV viral loads of less than 10 IU/mL, which is interesting and novel.


Subject(s)
Bacterial Proteins/genetics , Hepatitis B virus/isolation & purification , Polymerase Chain Reaction/methods , Thermus thermophilus/enzymology , Cloning, Molecular , Recombinases/genetics , Bacterial Proteins/isolation & purification , Bacterial Proteins/metabolism , Gene Expression , Hepatitis B virus/genetics , Polymerase Chain Reaction/instrumentation , Thermus thermophilus/genetics , Recombinases/isolation & purification , Recombinases/metabolism , Escherichia coli/genetics , Escherichia coli/metabolism
8.
Braz. j. microbiol ; 49(4): 885-890, Oct.-Dec. 2018. tab, graf
Article in English | LILACS | ID: biblio-974312

ABSTRACT

ABSTRACT In this study, the performance of the "RESIST-3 O.K.N. K-SeT" (Coris BioConcept, Gembloux, Belgium) immunochromatographic assay was evaluated in 132 Klebsiella pneumoniae comprising 102 carbapenem resistant and 30 carbapenem susceptible isolates. Genotypically known isolates of Gram negative bacteria (n = 22) including various species were also tested by the assay as controls. The isolates tested by the immunochromatographic assay and also were run PCR for bla KPC, bla IMP, bla VIM, bla NDM, and bla OXA-48. The rates of bla NDM, bla OXA-48, and bla KPC in carbapenem resistant isolates were found at 52.9%, 39.2%, and 2.0%, respectively. Both bla NDM and bla OXA-48 were found in six (5.9%) isolates. The results of the assay showed 100% concordance with those obtained by PCR in 132 K. pneumoniae. The agreement between the two methods was found to be identical at the isolate level. The assay also correctly detected all genotypically known isolates of Escherichia coli, Serratia marcescens, Citrobacter freundii, Enterobacter cloacae, K. pneumoniae carrying bla KPC, bla NDM, and/or bla OXA-48. On the other hand, the assay did not exhibit any cross-reaction in control isolates harboring bla IMP and bla VIM. We conclude that the RESIST-3 O.K.N. K-SeT is a reliable, rapid, and user friendly test and we recommend it for routine diagnostic laboratories.


Subject(s)
Humans , Bacterial Proteins/analysis , beta-Lactamases/analysis , Klebsiella Infections/microbiology , Immunoassay/methods , Klebsiella pneumoniae/enzymology , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , Turkey , beta-Lactamases/metabolism , Carbapenems/pharmacology , Polymerase Chain Reaction , Klebsiella pneumoniae/isolation & purification , Klebsiella pneumoniae/drug effects , Klebsiella pneumoniae/chemistry , Anti-Bacterial Agents/pharmacology
9.
Braz. j. microbiol ; 49(3): 601-606, July-Sept. 2018. tab, graf
Article in English | LILACS | ID: biblio-951806

ABSTRACT

Abstract Salmonella Gallinarum is a host-restrict pathogen that causes fowl typhoid, a severe systemic disease that is one of the major concerns to the poultry industry worldwide. When infecting the bird, SG makes use of evasion mechanisms to survive and to replicate within macrophages. In this context, phoPQ genes encode a two-component regulatory system (PhoPQ) that regulates virulence genes responsible for adaptation of Salmonella spp. to antimicrobial factors such as low pH, antimicrobial peptides and deprivation of bivalent cations. The role of the mentioned genes to SG remains to be investigated. In the present study a phoPQ-depleted SG strain (SG ΔphoPQ) was constructed and its virulence assessed in twenty-day-old laying hens susceptible to fowl typhoid. SG ΔphoPQ did cause neither clinical signs nor mortality in birds orally challenged, being non-pathogenic. Furthermore, this strain was not recovered from livers or spleens. On the other hand, chickens challenged subcutaneously with the mutant strain had discreet to moderate pathological changes and also low bacterial counts in liver and spleen tissues. These findings show that SG ΔphoPQ is attenuated to susceptible chickens and suggest that these genes are important during chicken infection by SG.


Subject(s)
Animals , Female , Poultry Diseases/microbiology , Salmonella Infections, Animal/microbiology , Bacterial Proteins/genetics , Salmonella enterica/metabolism , Salmonella enterica/pathogenicity , Gene Silencing , Poultry Diseases/pathology , Salmonella Infections, Animal/pathology , Spleen/microbiology , Spleen/pathology , Bacterial Proteins/metabolism , Virulence , Chickens , Salmonella enterica/genetics
10.
Braz. j. microbiol ; 49(3): 668-674, July-Sept. 2018. tab, graf
Article in English | LILACS | ID: biblio-951814

ABSTRACT

Abstract The virulence genes in invasive aspergillosis (IA) have not been analyzed adequately. The present study was designed to evaluate the expression of gpaB and sidA genes, which are important virulence genes in Aspergillus spp. from bronchoalveolar lavage (BAL) samples. Direct examination and culture on Czapek Agar and Sabouraud Dextrose Agar media were performed for 600 BAL specimens isolated from patients with possible aspergillosis. A Galactomannan ELISA assay was also carried out. The expression levels of the gpaB and sidA genes in isolates were analyzed using quantitative real-time PCR (qRT-PCR). We identified 2 species, including Aspergillus flavus (A. flavus) and Aspergillus fumigatus (A. fumigatus) in 25 positive samples for invasive aspergillosis as validated using GM-ELISA. A. flavus is the main pathogen threatening transplant recipients and cancer patients worldwide. In this study, A. flavus had low levels of the gpaB gene expression compared to A. fumigatus (p = 0.006). The highest sidA expression was detected in transplant recipients (p = 0.05). There was no significant correlation between sidA expression and underlying disease (p = 0.15). The sidA and gpaB gene expression patterns may provide evidence that these virulence genes play important roles in the pathogenicity of Aspergillus isolates; however, there are several regulatory genes responsible for the unexpressed sidA and gpaB genes in the isolates.


Subject(s)
Humans , Male , Female , Adult , Middle Aged , Aged , Aged, 80 and over , Aspergillosis/microbiology , Aspergillus flavus/metabolism , Aspergillus flavus/pathogenicity , Aspergillus fumigatus/metabolism , Aspergillus fumigatus/pathogenicity , Bacterial Proteins/metabolism , Aspergillus flavus/isolation & purification , Aspergillus flavus/genetics , Aspergillus fumigatus/isolation & purification , Aspergillus fumigatus/genetics , Bacterial Proteins/genetics , Virulence
11.
Braz. j. microbiol ; 49(1): 200-206, Jan.-Mar. 2018. tab, graf
Article in English | LILACS | ID: biblio-889189

ABSTRACT

ABSTRACT Bacteroides fragilis is the strict anaerobic bacteria most commonly found in human infections, and has a high mortality rate. Among other virulence factors, the remarkable ability to acquire resistance to a variety of antimicrobial agents and to tolerate nanomolar concentrations of oxygen explains in part their success in causing infection and colonizing the mucosa. Much attention has been given to genes related to multiple drug resistance derived from plasmids, integrons or transposon, but such genes are also detected in chromosomal systems, like the mar (multiple antibiotic resistance) locus, that confer resistance to a range of drugs. Regulators like MarR, that control expression of the locus mar, also regulate resistance to organic solvents, disinfectants and oxygen reactive species are important players in these events. Strains derived from the parental strain 638R, with mutations in the genes hereby known as marRI (BF638R_3159) and marRII (BF638R_3706) were constructed by gene disruption using a suicide plasmid. Phenotypic response of the mutant strains to hydrogen peroxide, cell survival assay against exposure to oxygen, biofilm formation, resistance to bile salts and resistance to antibiotics was evaluated. The results showed that the mutant strains exhibit statistically significant differences in their response to oxygen stress, but no changes were observed in survival when exposed to bile salts. Biofilm formation was not affected by either gene disruption. Both mutant strains however, became more sensitive to multiple antimicrobial drugs tested. This indicates that as observed in other bacterial species, MarR are an important resistance mechanism in B. fragilis.


Subject(s)
Humans , Anti-Bacterial Agents/pharmacology , Bacterial Proteins/genetics , Bacteroides fragilis/drug effects , Bacteroides fragilis/genetics , Bacteroides Infections/microbiology , Repressor Proteins/genetics , Bacterial Proteins/metabolism , Bacteroides fragilis/isolation & purification , Bacteroides fragilis/metabolism , Gene Expression Regulation, Bacterial/drug effects , Gene Silencing , Microbial Sensitivity Tests , Repressor Proteins/metabolism
12.
Braz. j. microbiol ; 49(1): 169-176, Jan.-Mar. 2018. tab, graf
Article in English | LILACS | ID: biblio-889211

ABSTRACT

ABSTRACT Major health challenges as the increasing number of cases of infections by antibiotic multiresistant microorganisms and cases of Alzheimer's disease have led to searching new control drugs. The present study aims to verify a new way of obtaining bioactive extracts from filamentous fungi with potential antimicrobial and acetylcholinesterase inhibitory activities, using epigenetic modulation to promote the expression of genes commonly silenced. For such finality, five filamentous fungal species (Talaromyces funiculosus, Talaromyces islandicus, Talaromyces minioluteus, Talaromyces pinophilus, Penicillium janthinellum) were grown or not with DNA methyltransferases inhibitors (procainamide or hydralazine) and/or a histone deacetylase inhibitor (suberohydroxamic acid). Extracts from T. islandicus cultured or not with hydralazine inhibited Listeria monocytogenes growth in 57.66 ± 5.98% and 15.38 ± 1.99%, respectively. Increment in inhibition of acetylcholinesterase activity was observed for the extract from P. janthinellum grown with procainamide (100%), when compared to the control extract (39.62 ± 3.76%). Similarly, inhibition of acetylcholinesterase activity increased from 20.91 ± 3.90% (control) to 92.20 ± 3.72% when the tested extract was obtained from T. pinophilus under a combination of suberohydroxamic acid and procainamide. Concluding, increases in antimicrobial activity and acetylcholinesterase inhibition were observed when fungal extracts in the presence of DNA methyltransferases and/or histone deacetylase modulators were tested.


Subject(s)
Anti-Bacterial Agents/pharmacology , Cholinesterase Inhibitors/pharmacology , Penicillium/chemistry , Talaromyces/chemistry , Acetylcholinesterase/chemistry , Acetylcholinesterase/metabolism , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/metabolism , Bacterial Proteins/chemistry , Bacterial Proteins/metabolism , Cholinesterase Inhibitors/chemistry , Cholinesterase Inhibitors/metabolism , Chromatin/metabolism , Listeria monocytogenes/drug effects , Listeria monocytogenes/enzymology , Listeria monocytogenes/growth & development , Penicillium/metabolism , Talaromyces/metabolism
13.
Braz. j. microbiol ; 49(1): 138-143, Jan.-Mar. 2018. tab, graf
Article in English | LILACS | ID: biblio-889188

ABSTRACT

ABSTRACT Q fever is a worldwide zoonosis caused by Coxiella burnetii—a small obligate intracellular Gram-negative bacterium found in a variety of animals. It is transmitted to humans by inhalation of contaminated aerosols from urine, feces, milk, amniotic fluid, placenta, abortion products, wool, and rarely by ingestion of raw milk from infected animals. Nested PCR can improve the sensitivity and specificity of testing while offering a suitable amplicon size for sequencing. Serial dilutions were performed tenfold to test the limit of detection, and the result was 10× detection of C. burnetti DNA with internal nested PCR primers relative to trans-PCR. Different biological samples were tested and identified only in nested PCR. This demonstrates the efficiency and effectiveness of the primers. Of the 19 samples, which amplify the partial sequence of C. burnetii, 12 were positive by conventional PCR and nested PCR. Seven samples—five spleen tissue samples from rodents and two tick samples—were only positive in nested PCR. With these new internal primers for trans-PCR, we demonstrate that our nested PCR assay for C. burnetii can achieve better results than conventional PCR.


Subject(s)
Humans , Bacterial Proteins/genetics , DNA Transposable Elements , Polymerase Chain Reaction/methods , Coxiella burnetii/isolation & purification , Transposases/genetics , Fever/microbiology , Bacterial Proteins/metabolism , Coxiella burnetii/classification , Coxiella burnetii/genetics , Transposases/metabolism
14.
Braz. j. microbiol ; 49(1): 13-15, Jan.-Mar. 2018. tab, graf
Article in English | LILACS | ID: biblio-889194

ABSTRACT

ABSTRACT As the largest genus in Actinobacteria family, Streptomyces species have the ability to synthesize numerous compounds of diverse structures with bioactivities. Streptomyces mangrovisoli MUSC 149T was previously isolated as a novel streptomycete from mangrove forest in east coast of Peninsular Malaysia. The high quality draft genome of MUSC 149T comprises 9,165,825 bp with G + C content of 72.5%. Through bioinformatics analysis, 21 gene clusters identified in the genome were associated with the production of bioactive secondary metabolites. The presence of these biosynthetic gene clusters in MUSC 149T suggests the potential exploitation of the strain for production of medically important compounds.


Subject(s)
Streptomyces/isolation & purification , Genome, Bacterial , Geologic Sediments/microbiology , Phylogeny , Streptomyces/classification , Streptomyces/genetics , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , Base Composition , DNA, Bacterial/genetics , Molecular Sequence Data , Base Sequence , Malaysia
15.
Braz. j. microbiol ; 49(1): 189-199, Jan.-Mar. 2018. tab, graf
Article in English | LILACS | ID: biblio-889209

ABSTRACT

ABSTRACT Nine Legionella pneumophila strains isolated from cooling towers and a standard strain (L. pneumophila serogroup 1, ATCC 33152, Philadelphia 1) were analyzed and compared in terms of motility, flagella structure, ability to form biofilms, enzymatic activities (hemolysin, nucleases, protease, phospholipase A, phospholipase C, acid phosphatase, alkaline phosphatase and lipase), hemagglutination capabilities, and pathogenicity in various host cells (Acanthamoeba castellanii ATCC 30234, mouse peritoneal macrophages and human peripheral monocytes). All the isolates of bacteria appeared to be motile and polar-flagellated and possessed the type-IV fimbria. Upon the evaluation of virulence factors, isolate 4 was found to be the most pathogenic strain, while 6 out of the 9 isolates (the isolates 1, 2, 3, 4, 5, and 7) were more virulent than the ATCC 33152 strain. The different bacterial strains exhibited differences in properties such as adhesion, penetration and reproduction in the hosts, and preferred host type. To our knowledge, this is the first study to compare the virulence of environmental L. pneumophila strains isolated in Turkey, and it provides important information relevant for understanding the epidemiology of L. pneumophila.


Subject(s)
Humans , Animals , Female , Mice , Bacterial Proteins/metabolism , Legionella pneumophila/metabolism , Virulence Factors/metabolism , Bacterial Proteins/genetics , Turkey/epidemiology , Legionnaires' Disease/microbiology , Legionella pneumophila/isolation & purification , Legionella pneumophila/genetics , Virulence Factors/genetics , Environmental Microbiology , Macrophages/microbiology , Mice, Inbred BALB C
16.
Braz. j. microbiol ; 49(1): 97-103, Jan.-Mar. 2018. graf
Article in English | LILACS | ID: biblio-889210

ABSTRACT

ABSTRACT Freezing temperatures are a major challenge for life at the poles. Decreased membrane fluidity, uninvited secondary structure formation in nucleic acids, and protein cold-denaturation all occur at cold temperatures. Organisms adapted to polar regions possess distinct mechanisms that enable them to survive in extremely cold environments. Among the cold-induced proteins, cold shock protein (Csp) family proteins are the most prominent. A gene coding for a Csp-family protein, cspB, was cloned from an arctic bacterium, Polaribacter irgensii KOPRI 22228, and overexpression of cspB greatly increased the freeze-survival rates of Escherichia coli hosts, to a greater level than any previously reported Csp. It also suppressed the cold-sensitivity of an E. coli csp-quadruple deletion strain, BX04. Sequence analysis showed that this protein consists of a unique domain at its N-terminal end and a well conserved cold shock domain at its C-terminal end. The most common mechanism of Csp function in cold adaption is melting of the secondary structures in RNA and DNA molecules, thus facilitating transcription and translation at low temperatures. P. irgensii CspB bound to oligo(dT)-cellulose resins, suggesting single-stranded nucleic acid-binding activity. The unprecedented level of freeze-tolerance conferred by P. irgensii CspB suggests a crucial role for this protein in survival in polar environments.


Subject(s)
Bacterial Proteins/metabolism , Flavobacteriaceae/physiology , Cold Shock Proteins and Peptides/metabolism , Arctic Regions , Bacterial Proteins/genetics , Gene Expression Regulation, Bacterial , Cold Temperature , Ecosystem , Flavobacteriaceae/isolation & purification , Flavobacteriaceae/genetics , Cold Shock Proteins and Peptides/genetics
17.
Electron. j. biotechnol ; 32: 26-34, Mar. 2018. graf, tab
Article in English | LILACS | ID: biblio-1022610

ABSTRACT

Background: A new ι-carrageenase-producing strain was screened from mangroves and authenticated as Pseudoalteromonas carrageenovora ASY5 in our laboratory. The potential application of this new strain was evaluated. Results: Medium compositions and culturing conditions in shaking flask fermentation were firstly optimized by single-factor experiment. ι-Carrageenase activity increased from 0.34 U/mL to 1.08 U/mL after test optimization. Optimal fermentation conditions were 20°C, pH 7.0, incubation time of 40 h, 15 g/L NaCl, 1.5% (w/v) yeast extract as nitrogen source, and 0.9% (w/v) ι-carrageenan as carbon source. Then, the crude ι-carrageenase was characterized. The optimum temperature and pH of the ι-carrageenase were 40°C and 8.0, respectively. The enzymatic activity at 35­40°C for 45 min retained more than 40% of the maximum activity. Meanwhile, The ι-carrageenase was inhibited by the addition of 1 mmol/L Cd2+ and Fe3+ but increased by the addition of 1 mmol/L Ag+, Ba2+, Ca2+, Co2+, Mn2+, Zn2+, Fe2+, and Al3+. The structure of oligosaccharides derived from ι-carrageenan was detected using electrospray ionization mass spectrometry (ESI-MS). The ι-carrageenase degraded ι-carrageenan, yielding disaccharides and tetrasaccharides as main products. Conclusions: The discovery and study of new ι-carrageenases are beneficial not only for the production of ι-carrageenan oligosaccharides but also for the further utilization in industrial production.


Subject(s)
Bacterial Proteins/metabolism , Pseudoalteromonas/enzymology , Glycoside Hydrolases/metabolism , Oligosaccharides/biosynthesis , Temperature , Carbon/metabolism , Carrageenan/biosynthesis , Spectrometry, Mass, Electrospray Ionization , Fermentation , Hydrogen-Ion Concentration , Hydrolysis , Nitrogen/metabolism
18.
Braz. j. infect. dis ; 22(1): 47-50, Jan.-feb. 2018. tab, graf
Article in English | LILACS | ID: biblio-1039209

ABSTRACT

ABSTRACT Carbapenemases have great importance in the global epidemiological scenario since infections with carbapenemase-producing bacteria are associated with high mortality, especially in hospitalized patients in intensive care units. This study describes two microorganisms producers of the New Delhi Metallo-b-lactamase, Klebsiella pneumoniae and Citrobacter freundii, from two patients admitted to a public hospital in Salvador, Bahia. These are the first clinical cases of New Delhi Metallo-b-lactamase described in microorganisms in the north and northeast Brazil. The isolates were characterized by antimicrobial susceptibility test, with resistance to all β-lactams including carbapenems, negative Modified Hodge Test and the synergy test with Ethylenediaminetetraacetic acid, Phenylboronic Acid and Cloxacillin was positive only with Ethylenediaminetetraacetic acid (difference of >5 mm in the inhibition zone between the disk without and with the inhibitor). Analysis by multiplex PCR for blaIMP, blaVIM, blaNDM, blaKPC and blaOXA-48 enzymes confirmed the presence of blaNDM gene. This report of two different New Delhi Metallo-b-lactamase-producing microorganisms in a different region of Brazil confirms the risk of spreading resistance genes between different species and emphasizes the need for prevention and control of infections caused by these pathogens, which have limited treatment options and have been linked to high mortality rates.


Subject(s)
Humans , Male , Adult , Aged , Bacterial Proteins/metabolism , beta-Lactamases/metabolism , Enterobacteriaceae/enzymology , Enterobacteriaceae Infections/microbiology , Bacterial Proteins/drug effects , beta-Lactamases/drug effects , Brazil , Carbapenems/pharmacology , Fatal Outcome , Drug Resistance, Bacterial , Enterobacteriaceae/isolation & purification , Enterobacteriaceae/drug effects , Multiplex Polymerase Chain Reaction , Hospitals, Public
19.
Braz. j. microbiol ; 49(supl.1): 93-100, 2018. tab, graf
Article in English | LILACS | ID: biblio-974332

ABSTRACT

Abstract Klebsiella pneumoniae is important human and animal pathogen that causes a wide spectrum of infections. In this study, isolates from cattle nasal swabs samples were identified by 16S rRNA, and to evaluate the antimicrobial susceptibility, virulence gene carrying levels, and multilocus sequence typing of K. pneumoniae isolates. 33 isolates of K. pneumoniae were isolated and identified in 213 nasal swabs samples, of which 12 were hypervirulent K. pneumoniae strains. Extended Spectrum Beta-Lactamases genes were found in 93.4% of the strains. Of which, TEM was the most prevalent (93.4%), followed by CTX-M and SHV were 57.6% and 39.4%, respectively. A main mutation pattern of quinoloneresistance-determining region, Thr83-Ieu and Asp87-Asn in gyrA and Ser87-Ile in parC, was detected in 33 K. pneumoniae isolates. All the isolates harbored at least two virulence factor genes, with ureA (97.0%) and wabG (91.0%) exhibiting high carriage rates in 33 K. pneumoniae isolates. MLST revealed 7 sequence types, of which 3 STs (2541, 2581 and 2844) were newly assigned. Using eBURST, ST2844 and ST2541 were assigned to new clonal complex 2844. Our study provides evidence and biological characteristics of K. pneumoniae isolates from cattle upper respiratory tract in Southwest China.


Subject(s)
Animals , Cattle , Bacterial Proteins/genetics , Klebsiella Infections/veterinary , Cattle Diseases/microbiology , Drug Resistance, Multiple, Bacterial , Virulence Factors/genetics , Klebsiella pneumoniae/isolation & purification , Klebsiella pneumoniae/drug effects , Anti-Bacterial Agents/pharmacology , Bacterial Proteins/metabolism , Klebsiella Infections/microbiology , China , Virulence Factors/metabolism , Multilocus Sequence Typing , Klebsiella pneumoniae/genetics , Klebsiella pneumoniae/metabolism
20.
Braz. j. microbiol ; 49(supl.1): 166-177, 2018. tab, graf
Article in English | LILACS | ID: biblio-974336

ABSTRACT

Abstract In the previous study, we used genome shuffling to improve fengycin production of the original strain Bacillus amyloliquefaciens ES-2-4. After two rounds of genome shuffling, a high-yield recombinant FMB72 strain that exhibited 8.30-fold increase in fengycin production was obtained. In this study, comparative proteomic analysis of the parental ES-2-4 and genome-shuffled FMB72 strains was conducted to examine the differentially expressed proteins. In the shuffled strain FMB72, 50 differently expressed spots (p < 0.05) were selected to be excised and analyzed using Matrix-Assisted Laser Desorption/Ionization Time of Flight/Time of Flight Mass Spectrometry, and finally 44 protein spots were confidently identified according to NCBI database. According to clusters of orthologous groups (COG) functional category analysis and related references, the differentially expressed proteins could be classified into several functional categories, including proteins involved in metabolism, energy generation and conversion, DNA replication, transcription, translation, ribosomal structure and biogenesis, cell motility and secretion, signal transduction mechanisms, general function prediction. Of the 44 identified proteins, signaling proteins ComA and Spo0A may positively regulate fengycin synthesis at transcriptional level. Taken together, the present study will be informative for exploring the exact roles of ComA and Spo0A in fengycin synthesis and explaining the molecular mechanism of fengycin synthesis.


Subject(s)
Bacterial Proteins/metabolism , Lipopeptides/biosynthesis , Bacillus amyloliquefaciens/genetics , Bacillus amyloliquefaciens/metabolism , Bacterial Proteins/genetics , Bacterial Proteins/chemistry , Genome, Bacterial , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization , DNA Shuffling , Proteomics , Bacillus amyloliquefaciens/chemistry
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