Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 90.484
Filtrar
1.
Food Microbiol ; 85: 103284, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31500712

RESUMO

The GAD system is widely present in several types of organisms and is known to play an important role in bacterial acid tolerance. There is only one account of this system playing a role in oxidative stress in bacteria and one in yeasts. Here we show for first time that it affects the oxidative stress resistance of a Gram-positive bacterium, (L. monocytogenes, tested in three strains; 10403S, EGD-e, and LO28). We found a statistically significant reduction in survival after H2O2 exposure in ΔgadD3 and ΔgadD2 of EGD-e and in ΔgadD1 of LO28. Furthermore, we observed a lag phase prolongation in ΔgadD3 of 10403S and EGD-e and a larger inhibition zone in disk diffusion assay for ΔgadD1 and ΔgadD3 of EGD-e upon H2O2 exposure. All GAD genes playing a role in oxidative stress resistance are part of GADi system and this occurs partly through catalase activity, while the most potent GADe system plays no role. The latter effects could occur through the GABA shunt, but we show here that mutants in succinate semialdehyde dehydrogenase do not show a phenotype suggesting that either effects are through the GABA transaminase or, this pathway is not involved. Our study highlights for first time the role of the GAD system in oxidative stress resistance of a Gram-positive bacterium, which could be used in Food Hurdle Technology to eliminate pathogens such as L. monocytogenes, while it gives an insight on the general mechanism.


Assuntos
Glutamato Descarboxilase/metabolismo , Peróxido de Hidrogênio/farmacologia , Listeria monocytogenes/efeitos dos fármacos , Listeria monocytogenes/enzimologia , Estresse Oxidativo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Deleção de Genes , Regulação Bacteriana da Expressão Gênica , Glutamato Descarboxilase/genética , Concentração de Íons de Hidrogênio , Listeria monocytogenes/genética
2.
Int J Food Microbiol ; 312: 108363, 2020 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-31669766

RESUMO

Several studies report the presence of Helicobacter pylori (H. pylori) in seawater either free or attached to planktonic organism. After considering the role played by plankton in the food chain of most aquatic ecosystems and the possible role that seafood products can assume in the transmission of H. pylori to humans, the aim of this study was to assess the survival of H. pylori in artificially contaminated Mytilus galloprovincialis (M. galloprovincialis). A traditional culture method and a reverse transcriptase-PCR (RT-PCR) assay were employed to detect the mRNA of known virulence factor (VacA) which can be considered use a marker of bacterial viability. The obtained results clearly show that H. pylori is able to survive in artificially contaminated mussels for 6 days (2 days in a cultivable form and 4 days in a non-cultivable form).


Assuntos
Helicobacter pylori/isolamento & purificação , Viabilidade Microbiana/genética , Mytilus/microbiologia , Animais , Proteínas de Bactérias/genética , Ecossistema , Helicobacter pylori/genética , Humanos , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Alimentos Marinhos , Água do Mar/microbiologia
3.
Arch Oral Biol ; 109: 104578, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31589997

RESUMO

OBJECTIVE: The aim of this study was to observe the effect of V. parvula on the physiological activity of S. mutans and elucidate the role of V. parvula on dental caries. DESIGN: We constructed dual-species biofilms formed by V. parvula and S. mutans, and measured the pH dynamics, biofilm growth, Extracellular Polysaccharide (EPS) synthesis, and expression of S. mutans EPS synthesis-associated genes affected by V. parvula. RESULTS: pH dynamics were not altered when V. parvula and S. mutans were co-cultured during a 120 -h test period. However, S. mutans cell number and EPS synthesis in dual-species biofilms were found to be significantly higher than in single-species biofilms. Moreover, expression levels of genes encoding glucosyltransferases (gtfs), gtfB and gtfC specifically, were up-regulated when S. mutans was co-cultured with V. parvula. CONCLUSIONS: Our findings indicate that V. parvula is not, as previously thought, protective and associated with caries health. On the contrary, V. parvula might participate in caries development through interactions with S. mutans. This study suggests that V. parvula may have an impact on the pathogenesis of dental caries.


Assuntos
Biofilmes , Streptococcus mutans/fisiologia , Veillonella/fisiologia , Proteínas de Bactérias/genética , Técnicas de Cocultura , Cárie Dentária/microbiologia , Matriz Extracelular de Substâncias Poliméricas , Regulação Bacteriana da Expressão Gênica , Glucosiltransferases/genética
4.
APMIS ; 128(1): 35-40, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31628868

RESUMO

Kingella kingae colonizes the upper airways in children and has been recognized as the most common causative agent of osteoarticular infections (OAI) in children below 4 years of age. This is the first Scandinavian study to investigate oropharyngeal K. kingae carriage in healthy children. From June 2015 to August 2016, we recruited 198 healthy children aged 11-14 months from routine consultations at health promotion centers in Hordaland County, Norway for a cross-sectional study. After their parents had provided informed consent; demographic data were registered, and an oropharyngeal swab was collected. The oropharyngeal swab was analyzed with a real-time PCR assay specific to K. kingae targeting the RTX toxin locus. Results showed an asymptomatic carriage rate of 12.6%. A striking and highly significant difference was observed between the children that had started attending day care facilities as compared with children still being at home (33.33% vs 8.5%; p < 0.001). K. kingae is prevalent in young children in Norway. This study emphasize that K. kingae should be considered an important etiological agent in OAI. Transmission seems to be facilitated in day care facilities. The correlation between oropharyngeal carriage and OAI needs to be further explored.


Assuntos
Portador Sadio/epidemiologia , Portador Sadio/microbiologia , Creches , Kingella kingae/isolamento & purificação , Infecções por Neisseriaceae/epidemiologia , Orofaringe/microbiologia , Infecções Assintomáticas/epidemiologia , Proteínas de Bactérias/genética , Estudos Transversais , Feminino , Humanos , Lactente , Kingella kingae/genética , Masculino , Noruega/epidemiologia , Osteomielite/diagnóstico , Osteomielite/microbiologia , Reação em Cadeia da Polimerase , Prevalência , Estudos Prospectivos
5.
APMIS ; 128(1): 48-60, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31693234

RESUMO

Klebsiella pneumoniae is an important opportunistic pathogen with significant potential for virulence and multidrug resistance. Treatment failure often occurs because the pathogen may couple virulence and drug resistance with the stringent response. This study assessed the role of the spoT gene in environmental and nutritional stress tolerance, exopolysaccharide capsule production and biofilm formation. spoT mutants were constructed using the lambda red recombinase technique, and mutant and wild-type (WT) strains were exposed to limiting concentrations of carbon (glucose), phosphate and aminoacid, and environmental stresses of ethanol, salt and heat. Cell viability, capsule production and cell length were assessed as well as the ability to grow biofilm under antibiotic pressure using gentamicin and ceftazidime. spoT mutants were more susceptible to stresses versus WT; the reverse was true for survival during biofilm susceptibility assay (p < 0.05), especially when carbon and phosphate were present. spoT mutants were elongated and lacked a capsule versus WT and non-starved strains. The inability to produce capsule in mutants before and after starvation was likely a general effect of spoT mutation. These data suggest that the spoT-mediated stringent response is important for K. pneumoniae in conditions of nutrient limitation, environmental stress and antimicrobial pressure.


Assuntos
Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Biofilmes/crescimento & desenvolvimento , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/fisiologia , Estresse Fisiológico , Aminoácidos/química , Farmacorresistência Bacteriana , Etanol/farmacologia , Regulação Bacteriana da Expressão Gênica , Glucose/química , Humanos , Klebsiella pneumoniae/efeitos dos fármacos , Fosfatos/química , Cloreto de Sódio/farmacologia , Virulência/genética , Fatores de Virulência
6.
World J Microbiol Biotechnol ; 36(1): 9, 2019 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-31858269

RESUMO

Campylobacter jejuni is the one of the leading cause of bacterial food borne gastroenteritis. PglB, a glycosyltransferase, plays a crucial role of mediating glycosylation of numerous periplasmic proteins. It catalyzes N-glycosylation at the sequon D/E-X1-N-X2-S/T in its substrate proteins. Here we report that the PglB itself is a glycoprotein which self-glycosylates at N534 site in its DYNQS sequon by its own catalytic WWDYG motif. Site-directed mutagenesis, lectin Immunoblot, and mobility shift assays confirmed that the DYNQS is an N-glycosylation motif. PglB's N-glycosylation motif is structurally and functionally similar to its widely studied glycosylation substrate, the OMPH1. Its DYNQS motif forms a solvent-exposed crest. This motif is close to a cluster of polar and hydrophilic residues, which form a loop flanked by two α helices. This arrangement extremely apposite for auto-glycosylation at N534. This self-glycosylation ability of PglB could mediate C. jejuni's ability to colonize the intestinal epithelium. Further this capability may also bear significance for the development of novel conjugated vaccines and diagnostic tests.


Assuntos
Campylobacter jejuni/enzimologia , Glicoproteínas/química , Hexosiltransferases/química , Proteínas de Membrana/química , Sequência de Aminoácidos , Proteínas da Membrana Bacteriana Externa/genética , Proteínas de Bactérias/genética , Glicosilação , Hexosiltransferases/genética , Hexosiltransferases/imunologia , Proteínas de Membrana/genética , Proteínas de Membrana/imunologia , Modelos Moleculares , Mutagênese Sítio-Dirigida , Filogenia , Conformação Proteica , Alinhamento de Sequência , Análise de Sequência de Proteína , Vacinas
7.
Bratisl Lek Listy ; 120(12): 935-940, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31855054

RESUMO

OBJECTIVES: We focused on detecting the most frequent resistance mechanisms in selected multidrug-resistant (MDR) strains and determining their antimicrobial resistance. BACKGROUND: MDR pathogens pose urgent public health threat due to limited treatment options, rigorous control measures and significant mortality. METHODS: We confirmed extended-spectrum ß-lactamase (ESBL) and carbapenemase producing Enterobacteriaceae through guidelines, as well following ß-lactamases: AmpC by cloxacillin, class A carbapenemase with phenylboronic acid, class B metallo-ß-lactamase with ethylenediaminetetraacetic acid. Multilocus sequence typing was used to investigate 20 Escherichia coli strains. RESULTS: Overall 205 mostly ESBL Escherichia coli demonstrated resistance against amikacin (4.7 %), tigecycline (1.2 %), and no resistance to ceftazidime/avibactam, meropenem, nitrofurantoin and fosfomycin. Out of 41 Klebsiella species (spp.), 37 (90.2 %) showed carbapenemase activity, 13 (35.1 %) of class A and 24 (64.9 %) of class B. Resistance was following: meropenem 66.7 %, tigecyclin 10.2 % and colistin 0 %. From Enterobacter spp. 21 strains, 14 (66.7 %) were ESBL, 5 produced ESBL and/or AmpC and 2 were MDR. We ascertained 14 (70 %) E. coli sequence type - ST131. CONCLUSIONS: The study revealed various resistance mechanisms in concert with different agents and association of specific ST131 within E. coli. These characteristics considerably contribute to emergence of antimicrobial resistance (Tab. 4, Ref. 30).


Assuntos
Antibacterianos/farmacologia , Proteínas de Bactérias/metabolismo , Enterobacteriáceas Resistentes a Carbapenêmicos/efeitos dos fármacos , Enterobacteriaceae/enzimologia , Escherichia coli/efeitos dos fármacos , Escherichia coli/enzimologia , Klebsiella pneumoniae/efeitos dos fármacos , beta-Lactamases/metabolismo , Adulto , Idoso , Proteínas de Bactérias/genética , Enterobacteriáceas Resistentes a Carbapenêmicos/enzimologia , Enterobacteriáceas Resistentes a Carbapenêmicos/genética , Enterobacteriáceas Resistentes a Carbapenêmicos/isolamento & purificação , Farmacorresistência Bacteriana , Enterobacteriaceae/classificação , Infecções por Enterobacteriaceae/microbiologia , Escherichia coli/genética , Escherichia coli/isolamento & purificação , Humanos , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/isolamento & purificação , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , beta-Lactamases/genética
8.
Pol J Microbiol ; 68(4): 477-491, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31880892

RESUMO

This study explored a potential treatment against methicillin-resistant Staphylococcus aureus (MRSA) infections that combines thioridazine (TZ), an efflux pump inhibitor, and miconazole (MCZ), an autolysis inducer, with the anti-microbial drug cloxacillin (CXN). In vitro, the combination treatment of TZ and MCZ significantly reduced 4096-fold (Σ (FIC) = 0.1 - 1.25) the MIC value of CXN against S. aureus. In vivo, the combination therapy significantly relieved breast redness and swelling in mice infected with either clinical or standard strains of S. aureus. Meanwhile, the number of bacteria isolated from the MRSA135-infected mice decreased significantly (p = 0.0427 < 0.05) after the combination therapy when compared to monotherapy. Moreover, the number of bacteria isolated from the mice infected with a reference S. aureus strain also decreased significantly (p = 0.0191 < 0.05) after the combination therapy when compared to monotherapy. The pathological changes were more significant in the CXN-treated group when compared to mice treated with a combination of three drugs. In addition, we found that combination therapy reduced the release of the bacteria-stimulated cytokines such as IL-6, IFN-γ, and TNF-α. Cytokine assays in serum revealed that CXN alone induced IL-6, IFN-γ, and TNF-α in the mouse groups infected with ATCC 29213 or MRSA135, and the combination of these three drugs significantly reduced IL-6, IFN-γ, and TNF-α concentrations. Also, the levels of TNF-α and IFN-γ in mice treated with a combination of three drugs were significantly lower than in the CXN-treated group. Given the synergistic antibacterial activity of CXN, we concluded that the combination of CXN with TZ, and MCZ could be developed as a novel therapeutic strategy against S. aureus.This study explored a potential treatment against methicillin-resistant Staphylococcus aureus (MRSA) infections that combines thioridazine (TZ), an efflux pump inhibitor, and miconazole (MCZ), an autolysis inducer, with the anti-microbial drug cloxacillin (CXN). In vitro, the combination treatment of TZ and MCZ significantly reduced 4096-fold (Σ (FIC) = 0.1 ­ 1.25) the MIC value of CXN against S. aureus. In vivo, the combination therapy significantly relieved breast redness and swelling in mice infected with either clinical or standard strains of S. aureus. Meanwhile, the number of bacteria isolated from the MRSA135-infected mice decreased significantly (p = 0.0427 < 0.05) after the combination therapy when compared to monotherapy. Moreover, the number of bacteria isolated from the mice infected with a reference S. aureus strain also decreased significantly (p = 0.0191 < 0.05) after the combination therapy when compared to monotherapy. The pathological changes were more significant in the CXN-treated group when compared to mice treated with a combination of three drugs. In addition, we found that combination therapy reduced the release of the bacteria-stimulated cytokines such as IL-6, IFN-γ, and TNF-α. Cytokine assays in serum revealed that CXN alone induced IL-6, IFN-γ, and TNF-α in the mouse groups infected with ATCC 29213 or MRSA135, and the combination of these three drugs significantly reduced IL-6, IFN-γ, and TNF-α concentrations. Also, the levels of TNF-α and IFN-γ in mice treated with a combination of three drugs were significantly lower than in the CXN-treated group. Given the synergistic antibacterial activity of CXN, we concluded that the combination of CXN with TZ, and MCZ could be developed as a novel therapeutic strategy against S. aureus.


Assuntos
Antibacterianos/farmacologia , Proteínas de Bactérias/antagonistas & inibidores , Farmacorresistência Bacteriana , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/efeitos dos fármacos , beta-Lactamas/farmacologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Bacteriólise/efeitos dos fármacos , Cloxacilina/farmacologia , Quimioterapia Combinada , Humanos , Proteínas de Membrana Transportadoras/genética , Proteínas de Membrana Transportadoras/metabolismo , Miconazol/farmacologia , Testes de Sensibilidade Microbiana , Infecções Estafilocócicas/tratamento farmacológico , Staphylococcus aureus/citologia , Staphylococcus aureus/genética , Staphylococcus aureus/metabolismo , Tioridazina/farmacologia
9.
Pol J Microbiol ; 68(4): 541-548, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31880897

RESUMO

Analysis of the epidemiology of Staphylococcus aureus (SA) ocular infections and virulence factors of the isolates with a special emphasis on their drug resistance, and the ability of biofilm formation. In a period from 2009 to 2013, 83 isolates of SA were prospectively collected and preserved in a multicenter laboratory-based study carried out in southern Poland. Epidemiological, phenotypic, and genotypic analyses were performed. The resistance and virulence genes were analyzed. Screening for the biofilm formation was provided. Among the materials derived from ocular infections from 456 patients, SA was found in 18.2% (n = 83) of cases (one SA isolate per one patient). Most infections were identified in the age group of over 65 years (OR 8.4 95%CI; 1.03-68.49). The majority of patients (73.4%) were hospitalized. Among the virulence and resistance genes, the most frequently detected were the lukE (72.2%, n = 60) and ermA (15.6%, n = 13) genes. A positive result of the CRA test (the ability of biofilm formation) was found in 66.2% (n = 55) of isolates. Among the strains under study, 6.0% (n = 5) had the methicillin-resistant Staphylococcus aureus phenotype, and 26.5% (n = 22) had the macrolide-lincosamide-streptogramin B phenotype. In 48 (57.8%) isolates the neomycin resistance was revealed. All isolates under study were sensitive to vancomycin. The population most susceptible to ocular SA infections consists of hospitalized patients aged 65 and more. The SA strains under study showed the increased ability to biofilm formation. In the strains tested, high susceptibility to chloramphenicol and fluoroquinolones was demonstrated. However, the high level of drug resistance to neomycin detected in this study among SA isolates and the blood-ocular barrier makes it difficult to treat ocular infections.Analysis of the epidemiology of Staphylococcus aureus (SA) ocular infections and virulence factors of the isolates with a special emphasis on their drug resistance, and the ability of biofilm formation. In a period from 2009 to 2013, 83 isolates of SA were prospectively collected and preserved in a multicenter laboratory-based study carried out in southern Poland. Epidemiological, phenotypic, and genotypic analyses were performed. The resistance and virulence genes were analyzed. Screening for the biofilm formation was provided. Among the materials derived from ocular infections from 456 patients, SA was found in 18.2% (n = 83) of cases (one SA isolate per one patient). Most infections were identified in the age group of over 65 years (OR 8.4 95%CI; 1.03-68.49). The majority of patients (73.4%) were hospitalized. Among the virulence and resistance genes, the most frequently detected were the lukE (72.2%, n = 60) and ermA (15.6%, n = 13) genes. A positive result of the CRA test (the ability of biofilm formation) was found in 66.2% (n = 55) of isolates. Among the strains under study, 6.0% (n = 5) had the methicillin-resistant Staphylococcus aureus phenotype, and 26.5% (n = 22) had the macrolide-lincosamide-streptogramin B phenotype. In 48 (57.8%) isolates the neomycin resistance was revealed. All isolates under study were sensitive to vancomycin. The population most susceptible to ocular SA infections consists of hospitalized patients aged 65 and more. The SA strains under study showed the increased ability to biofilm formation. In the strains tested, high susceptibility to chloramphenicol and fluoroquinolones was demonstrated. However, the high level of drug resistance to neomycin detected in this study among SA isolates and the blood-ocular barrier makes it difficult to treat ocular infections.


Assuntos
Proteínas de Bactérias/genética , Farmacorresistência Bacteriana , Infecções Oculares/microbiologia , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/genética , Fatores de Virulência/genética , Adolescente , Adulto , Idoso , Antibacterianos/farmacologia , Proteínas de Bactérias/metabolismo , Criança , Infecções Oculares/epidemiologia , Feminino , Humanos , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Polônia/epidemiologia , Infecções Estafilocócicas/epidemiologia , Staphylococcus aureus/classificação , Staphylococcus aureus/metabolismo , Fatores de Virulência/metabolismo , Adulto Jovem
10.
Pol J Microbiol ; 68(3): 353-369, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31880881

RESUMO

Listeria monocytogenes is the etiological factor of listeriosis. The main source of these organisms is food, including dairy products. The aim was to determine the multiple correlations between the drug susceptibility, virulence genes (VGs), and biofilm formation on silicone teat cups of milk-borne and human L. monocytogenes strains. The spread of L. monocytogenes via contaminated teat rubbers was assessed. The L. monocytogenes strains recovered from milk (18), human blood (10), and the reference strain ATCC®19111™ were used in the study. Penicillin resistance was the most prevalent resistance in the milk isolates (n=8; 44.4%), whereas among clinical strains erythromycin resistance was predominating - (n=6; 60%). The most frequent VGs among strains isolated from milk were hlyA (100%) and plcB (100%) whereas in strains isolated from blood - hlyA (100%) and prfA (90%). All tested VGs were present in 50% of blood isolates and 11% of milk-borne strains. The strains isolated from milk formed a significantly stronger biofilm. The strains with more numerous virulence genes were resistant to more antibiotics and formed a stronger biofilm. It was shown that contaminated teat cups might contribute to the transmission of L. monocytogenes in the herd. It seems reasonable to monitor the occurrence of L. monocytogenes biofilm in a dairy processing environment.Listeria monocytogenes is the etiological factor of listeriosis. The main source of these organisms is food, including dairy products. The aim was to determine the multiple correlations between the drug susceptibility, virulence genes (VGs), and biofilm formation on silicone teat cups of milk-borne and human L. monocytogenes strains. The spread of L. monocytogenes via contaminated teat rubbers was assessed. The L. monocytogenes strains recovered from milk (18), human blood (10), and the reference strain ATCC®19111™ were used in the study. Penicillin resistance was the most prevalent resistance in the milk isolates (n=8; 44.4%), whereas among clinical strains erythromycin resistance was predominating ­ (n=6; 60%). The most frequent VGs among strains isolated from milk were hlyA (100%) and plcB (100%) whereas in strains isolated from blood ­ hlyA (100%) and prfA (90%). All tested VGs were present in 50% of blood isolates and 11% of milk-borne strains. The strains isolated from milk formed a significantly stronger biofilm. The strains with more numerous virulence genes were resistant to more antibiotics and formed a stronger biofilm. It was shown that contaminated teat cups might contribute to the transmission of L. monocytogenes in the herd. It seems reasonable to monitor the occurrence of L. monocytogenes biofilm in a dairy processing environment.


Assuntos
Sangue/microbiologia , Listeria monocytogenes/isolamento & purificação , Listeriose/microbiologia , Leite/microbiologia , Animais , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Biofilmes , Bovinos , Humanos , Listeria monocytogenes/classificação , Listeria monocytogenes/genética , Listeria monocytogenes/fisiologia , Listeriose/transmissão , Filogenia , Fatores de Virulência/genética , Fatores de Virulência/metabolismo
11.
Chem Commun (Camb) ; 55(92): 13864-13867, 2019 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-31670736

RESUMO

The crystal structures of the conserved region domains of HtaA and HtaB, which act as heme binding/transport proteins in the heme uptake machinery in Corynebacterium glutamicum, are determined for the first time. The molecular mechanism of heme transfer among these proteins is proposed based on the spectroscopic and structural analyses.


Assuntos
Corynebacterium glutamicum/metabolismo , Heme/metabolismo , Sequência de Aminoácidos , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Transporte Biológico , Heme/química , Ligação Proteica , Estrutura Terciária de Proteína
12.
Biochemistry (Mosc) ; 84(11): 1403-1410, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31760926

RESUMO

Genomes of photoautotrophic organisms containing type I photosynthetic reaction center were searched for the rnf genes encoding Na+-translocating ferredoxin:NAD+ oxidoreductase (RNF). These genes were absent in heliobacteria, cyanobacteria, algae, and plants; however, genomes of many green sulfur bacteria (especially marine ones) were found to contain the full rnf operon. Analysis of RNA isolated from the marine green sulfur bacterium Chlorobium phaeovibrioides revealed a high level of rnf expression. It was found that the activity of Na+-dependent flavodoxin:NAD+ oxidoreductase detected in the membrane fraction of Chl. phaeovibrioides was absent in the membrane fraction of the freshwater green sulfur bacterium Chlorobaculum limnaeum, which is closely related to Chl. phaeovibrioides but whose genome lacks the rnf genes. Illumination of the membrane fraction of Chl. phaeovibrioides but not of Cba. limnaeum resulted in the light-induced NAD+ reduction. Based on the obtained data, we concluded that in some green sulfur bacteria, RNF may be involved in the NADH formation that should increase the efficiency of light energy conservation in these microorganisms and can serve as the first example of the use of Na+ energetics in photosynthetic electron transport chains.


Assuntos
Proteínas de Bactérias/metabolismo , Chlorobi/metabolismo , Oxirredutases/metabolismo , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Transporte de Elétrons , Luz , NAD/química , NAD/metabolismo , Oxirredutases/química , Oxirredutases/genética , Fotossíntese , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/química , Proteínas Recombinantes/isolamento & purificação
13.
Sichuan Da Xue Xue Bao Yi Xue Ban ; 50(5): 629-634, 2019 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-31762229

RESUMO

OBJECTIVE: To establish a way for screening Mycobacterium mutants through adding the screening markers into pJV53. METHODS: The sucrose counter selection gene SacB and mutant hygromycin-resistant gene hygS were inserted into pJV53; The recovery of the hygromycin-resistance indicated the successful homologous recombination in Mycobacterium smegmatis (Ms), which could serve as mutant screening marker; The sucrose counter selection could be used to screen the plasmid-free mutants. RESULTS: The recombinant plasmid pJV53-SacB-hygS were successfully constructed. The rifampin-resistant rpoB D516Y and rpoB H526Q mutants and MSMEG_4487 G188A mutant were efficiently screened out. All mutants had shed the plasmid successfully. CONCLUSION: pJV53-SacB-hygS can efficiently contribute to construct and screen the mutants and to get the mutants shedding the plasmid self, which has high value of extensive application; the D516Y and H526Q mutations in gene rpoB of Mycobacterium tuberculosis contribute to its rifampin-resistance.


Assuntos
Farmacorresistência Bacteriana/genética , Recombinação Homóloga , Mycobacterium smegmatis/genética , Mycobacterium tuberculosis/genética , Proteínas de Bactérias/genética , RNA Polimerases Dirigidas por DNA/genética , Testes de Sensibilidade Microbiana , Mutação , Mycobacterium tuberculosis/efeitos dos fármacos , Plasmídeos/genética , Rifampina/farmacologia
14.
J Photochem Photobiol B ; 201: 111637, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31706086

RESUMO

Plants are considered to be a leading source for possible human therapeutic agents. This holistic study has investigated the anti-quorum sensing (anti-QS), anti-infection, antioxidant and anti-photoaging properties of neglected plant Diplocyclos palmatus. The results showed that D. palmatus methanolic leaf extract (DPME) effectively inhibited the quorum sensing (QS) regulated virulence factor production as well as biofilm formation in Serratia marcescens. The transcriptomic analysis revealed that DPME significantly downed the expression of QS-regulated genes such as fimA, fimC, flhC, bsmB, pigP and shlA in S. marcescens, which supports the outcome of in vitro bioassays. Further, the docking study revealed that the presence of active compounds, namely tocopherols and phytol, DPME exhibited its anti-QS activity against S. marcescens. In addition, DPME treatment extended the lifespan of S. marcescens infected C. elegans by the action of dropping the internal accumulation. Further, qPCR analysis clearly revealed that DPME treatment significantly up-regulated the expression of the lifespan-related gene (daf-16) and immune-related genes (clec-60, clec-87, lys-7 and bec-1) in S. marcescens infected C.elegans. On the other hand, DPME extensively reduced the UV-A induced ROS stress, thereby, extended the lifespan in UV-A photoaged C. elegans. Further, the qPCR analysis also confirmed the up-regulation of daf-16, clec-60, clec-87 and col-19 genes which advocated the improvement of the lifespan, healthspan and collagen production in UV-A photoaged C. elegans. Further bioassays evidenced that that the lifespan extension of photoaged C. elegans was accomplished by the actions of antioxidants such as tocopherols and phytol in DPME.


Assuntos
Envelhecimento/efeitos dos fármacos , Caenorhabditis elegans/efeitos da radiação , Cucurbitaceae/química , Extratos Vegetais/farmacologia , Percepção de Quorum/efeitos dos fármacos , Serratia marcescens/fisiologia , Raios Ultravioleta , Envelhecimento/efeitos da radiação , Animais , Antioxidantes/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Biofilmes/efeitos dos fármacos , Caenorhabditis elegans/efeitos dos fármacos , Caenorhabditis elegans/fisiologia , Colágeno/metabolismo , Cucurbitaceae/metabolismo , Longevidade/efeitos dos fármacos , Extratos Vegetais/química , Folhas de Planta/química , Folhas de Planta/metabolismo , Infecções por Serratia/patologia , Infecções por Serratia/veterinária , Regulação para Cima/efeitos dos fármacos
15.
J Agric Food Chem ; 67(46): 12816-12823, 2019 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-31675231

RESUMO

Microbial degradation plays a major role in the dissipation of pendimethalin, and nitroreduction is an initial and detoxicating step. Previously, a pendimethalin nitroreductase, PNR, was identified in Bacillus subtilis Y3. Here, another pendimethalin nitroreductase from strain Y3, LNR, was identified. LNR shares only 40% identity with PNR and reduces the aromatic ring C-6 nitro group of pendimethalin and both nitro groups of trifluralin, butralin, and oryzalin. The catalytic activities against the four dinitroanilines were much higher for LNR than for PNR. lnr deletion significantly reduced the pendimethalin-reduction activity (60% activity loss), while pnr deletion led to only 30% activity loss, indicating that both LNR and PNR were involved in pendimethalin nitroreduction in strain Y3; however, LNR played the major role. This study facilitates the elucidation of pendimethalin catabolism and provides degrading enzyme resources for the removal of dinitroaniline herbicide residues in environment and agricultural products.


Assuntos
Compostos de Anilina/metabolismo , Bacillus subtilis/enzimologia , Proteínas de Bactérias/metabolismo , Herbicidas/metabolismo , Nitrorredutases/metabolismo , Sequência de Aminoácidos , Compostos de Anilina/química , Bacillus subtilis/classificação , Bacillus subtilis/genética , Bacillus subtilis/metabolismo , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Biodegradação Ambiental , Herbicidas/química , Nitrorredutases/química , Nitrorredutases/genética , Filogenia , Alinhamento de Sequência
16.
Mol Plant Microbe Interact ; 32(12): 1577-1580, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31618137

RESUMO

The Xanthomonas genus, comprises more than 30 species of gram-negative bacteria, most of which are pathogens of plants with high economic value, such as rice, common bean, and maize. Transcription activator-like effectors (TALEs), which act by regulating the host gene expression, are some of the major virulence factors of these bacteria. We present a novel tool to identify TALE genes in the genome of Xanthomonas strains and their respective targets. The analysis of the results obtained by TargeTALE in a proof-of-concept validation demonstrate that, at optimum setting, approximately 93% of the predicted target genes with available expression data were confirmed as upregulated during the infection, indicating that the tool might be useful for researchers in the field.


Assuntos
Genoma Bacteriano , Efetores Semelhantes a Ativadores de Transcrição , Xanthomonas , Proteínas de Bactérias/genética , Interações Hospedeiro-Patógeno/genética , Oryza/microbiologia , Efetores Semelhantes a Ativadores de Transcrição/genética , Fatores de Virulência/genética , Xanthomonas/genética
17.
J Agric Food Chem ; 67(45): 12502-12510, 2019 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-31623431

RESUMO

Succinic acid (SA) is applied in the food, chemical, and pharmaceutical industries. 5-Hydroxyleucine (5-HLeu) is a promising precursor for the biosynthesis of antituberculosis drugs. Here, we designed a promising synthetic route for the simultaneous production of SA and 5-HLeu by combining l-leucine dioxygenase (NpLDO), l-glutamate oxidase (LGOX), and catalase (CAT). Two bioconversion systems: "a multienzyme cascade catalysis in vitro" (MECCS) and "whole-cell catalysis system" (WCCS) were constructed. A high-activity NpLDO mutant was screened by error-prone polymerase chain reaction (PCR) and showed 6.1-fold improvement of catalytic activity. After optimization of reaction conditions, MECSS yielded 3.15 g/L SA and 3.92 g/L 5-HLeu, while the production of SA and 5-HLeu by the most effective WCSS reached 15.12 and 18.83 g/L, respectively. This is the first attempt to use ferrous iron/α-ketoglutarate-dependent dioxygenases for the simultaneous production of SA and hydroxy-amino-acid. This research provides a tool for industrial production of food of high-value products from low-cost raw materials.


Assuntos
Aminoácido Oxirredutases/química , Proteínas de Bactérias/química , Catalase/química , Dioxigenases/química , Leucina/química , Nostoc/metabolismo , Ácido Succínico/química , Aminoácido Oxirredutases/genética , Aminoácido Oxirredutases/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Biocatálise , Catalase/genética , Catalase/metabolismo , Dioxigenases/genética , Dioxigenases/metabolismo , Ácidos Cetoglutáricos/química , Ácidos Cetoglutáricos/metabolismo , Leucina/metabolismo , Nostoc/enzimologia , Nostoc/genética , Ácido Succínico/metabolismo
18.
Photochem Photobiol Sci ; 18(11): 2657-2660, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31624823

RESUMO

Mr4511 from Methylobacterium radiotolerans is a 164 amino acid protein built of a flavin mononucleotide (FMN) binding, blue-light responsive LOV (Light, Oxygen, Voltage) core domain plus flanking regions. In contrast to the majority of LOV domains, Mr4511 lacks a tryptophan residue that was previously identified as a major quencher for the FMN triplet state in photosensitizers for singlet oxygen (SO) engineered from these photoreceptors. Here we show that for Mr4511 it is sufficient to only mutate the reactive cysteine responsible for the photocycle (Cys71) in the native protein to generate an efficient SO photosensitizer: both C71S and C71G variants exhibit SO quantum yields of formation, ΦΔ, around 0.2 in air-saturated solutions. Under oxygen saturated conditions, ΦΔ reaches ∼0.5 in deuterated buffer. The introduction of Trp112 in the canonical position for LOV domains dramatically lowers ΦΔ to values comparable to miniSOG, one of the early FMN binding proteins touted as a SO sensitizer. Besides its SO properties, Mr4511 is also exceedingly robust against denaturation with urea and is more photostable than free FMN.


Assuntos
Proteínas de Bactérias/metabolismo , Methylobacterium/metabolismo , Oxigênio Singlete/metabolismo , Sequência de Aminoácidos , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Mononucleotídeo de Flavina/química , Mononucleotídeo de Flavina/metabolismo , Polarização de Fluorescência , Mutagênese Sítio-Dirigida , Oxigênio/química , Ligação Proteica , Teoria Quântica , Alinhamento de Sequência , Ureia/química
19.
Life Sci ; 237: 116947, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31605708

RESUMO

AIMS: Pseudomonas aeruginosa is one of the leading causes of opportunistic and hospital-acquired infections worldwide, which is frequently linked with clinical treatment difficulties. Ibuprofen, a widely used non-steroidal anti-inflammatory drug, has been previously reported to exert antimicrobial activity with the specific mechanism. We hypothesized that inhibition of P. aeruginosa with ibuprofen is involved in the quorum sensing (QS) systems. MAIN METHODS: CFU was utilized to assessed the growth condition of P. aeruginosa. Crystal violent staining and acridine orange staining was used to evaluate the biofilm formation and adherence activity. The detection of QS virulence factors such as pyocyanin, elastase, protease, and rhamnolipids were applied to investigation the anti-QS activity of ibuprofen against P. aeruginosa. The production of 3-oxo-C12-HSL and C4-HSL was confirmed by liquid chromatography/mass spectrometry analysis. qRT-PCR was used to identify the QS-related gene expression. Furthermore, we explored the binding effects between ibuprofen and QS-associated proteins with molecular docking. KEY FINDINGS: Ibuprofen inhibits P. aeruginosa biofilm formation and adherence activity. And the inhibitory effects of ibuprofen on C4-HSL levels were concentration-dependent (p < 0.05), while it has no effect on 3-oxo-C12-HSL. Moreover, ibuprofen attenuates the production of virulence factors in P. aeruginosa (p < 0.05). In addition, the genes of QS system were decreased after the ibuprofen treatment (p < 0.05). Of note, ibuprofen was binding with LuxR, LasR, LasI, and RhlR at high binding scores. SIGNIFICANCE: The antibiofilm and anti-QS activity of ibuprofen suggest that it can be a candidate drug for the treatment of clinical infections with P. aeruginosa.


Assuntos
Proteínas de Bactérias/genética , Biofilmes/crescimento & desenvolvimento , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Ibuprofeno/farmacologia , Pseudomonas aeruginosa/genética , Percepção de Quorum/efeitos dos fármacos , Fatores de Virulência/genética , Anti-Inflamatórios não Esteroides/farmacologia , Biofilmes/efeitos dos fármacos , Humanos , Infecções por Pseudomonas/tratamento farmacológico , Infecções por Pseudomonas/microbiologia , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/crescimento & desenvolvimento
20.
J Microbiol ; 57(10): 865-873, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31571125

RESUMO

Lignocellulose composed of complex carbohydrates and aromatic heteropolymers is one of the principal materials for the production of renewable biofuels. Lignocellulose-degrading genes from cold-adapted bacteria have a potential to increase the productivity of biological treatment of lignocellulose biomass by providing a broad range of treatment temperatures. Antarctic soil metagenomes allow to access novel genes encoding for the cold-active lignocellulose-degrading enzymes, for biotechnological and industrial applications. Here, we investigated the metagenome targeting cold-adapted microbes in Antarctic organic matter-rich soil (KS 2-1) to mine lignolytic and celluloytic enzymes by performing single molecule, real-time metagenomic (SMRT) sequencing. In the assembled Antarctic metagenomic contigs with relative long reads, we found that 162 (1.42%) of total 11,436 genes were annotated as carbohydrate-active enzymes (CAZy). Actinobacteria, the dominant phylum in this soil's metagenome, possessed most of candidates of lignocellulose catabolic genes like glycoside hydrolase families (GH13, GH26, and GH5) and auxiliary activity families (AA7 and AA3). The predicted lignocellulose degradation pathways in Antarctic soil metagenome showed synergistic role of various CAZyme harboring bacterial genera including Streptomyces, Streptosporangium, and Amycolatopsis. From phylogenetic relationships with cellular and environmental enzymes, several genes having potential for participating in overall lignocellulose degradation were also found. The results indicated the presence of lignocellulose-degrading bacteria in Antarctic tundra soil and the potential benefits of the lignocelluolytic enzymes as candidates for cold-active enzymes which will be used for the future biofuel-production industry.


Assuntos
Bactérias/enzimologia , Bactérias/genética , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Lignina/metabolismo , Metagenoma , Microbiologia do Solo , Regiões Antárticas , Bactérias/classificação , Bactérias/metabolismo , Proteínas de Bactérias/metabolismo , Biocombustíveis/análise , Temperatura Baixa , Filogenia , Solo/química , Tundra
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA