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2.
World J Microbiol Biotechnol ; 35(8): 127, 2019 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-31375931

RESUMO

Aeromonas hydrophila is a Gram-negative bacterium that causes serious infections in aquaculture and exhibits significant multidrug resistance. The LysR-type transcriptional regulator (LTTR) family proteins are a well-known group of transcriptional regulators involved in diverse physiological functions. However, the role of LTTRs in the regulation of bacterial resistance to antibiotics is still largely unknown. In this study, to further investigate the role of four putative LTTR family proteins (A0KIU1, A0KJ82, A0KPK0, and A0KQ63) in antibiotic resistance in A. hydrophila, their genes were cloned and overexpressed in engineered Escherichia coli. After the optimization of experimental conditions including incubation time, temperature, and IPTG concentration, these proteins were successfully purified, and their specific antibodies against mice were obtained. Using western blot analysis, we found that these LTTR family proteins were downregulated in A. hydrophila following antibiotic treatment, indicating that they may be involved in the regulation of antibiotic resistance. Additionally, minimum inhibitory concentration (MIC) assays of chloramphenicol (CM), chlortetracycline (CTC), ciprofloxacin (CF), furazolidone (FZ), and balofloxacin (BF) in E. coli showed that overexpression of these LTTRs led to increased sensitivity to several antibiotics. To further validate their functional role in antibiotic resistance, we demonstrated that bacteria with loss of A0KQ63 (ΔAHA_3980) exhibited multi-drug resistance properties. Our results indicate that these LTTR family proteins may play an important role in the antibiotic resistance of A. hydrophila, and the that underlying mechanisms controlling antibiotic resistance should be further investigated.


Assuntos
Aeromonas hydrophila/efeitos dos fármacos , Aeromonas hydrophila/genética , Farmacorresistência Bacteriana , Regulação Bacteriana da Expressão Gênica , Genes Reguladores , Fatores de Transcrição/metabolismo , Animais , Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Western Blotting , Clonagem Molecular , Escherichia coli/efeitos dos fármacos , Escherichia coli/genética , Escherichia coli/metabolismo , Deleção de Genes , Expressão Gênica , Perfilação da Expressão Gênica , Genes Bacterianos , Camundongos , Testes de Sensibilidade Microbiana , Fatores de Transcrição/análise , Fatores de Transcrição/genética
3.
Pestic Biochem Physiol ; 158: 185-200, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31378356

RESUMO

The present work describes the antimicrobial action of 25 monoterpenes (six hydrocarbons, five ketones, two aldehydes, six alcohols and six acetate analogues) against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus and antifungal activity against Aspergillus flavus. The antibacterial activity was evaluated by broth microdilution technique as a minimum inhibitory concentration (MIC) and the antifungal activity was performed by mycelia radial growth technique as the effective concentration causing 50% inhibition of the mycelial growth (EC50). The results showed that thymol and α-terpineol were the most potent against E. coli (MIC = 45 and 55 mg/L, respectively) and S. aureus (MIC = 135 and 225 mg/L, respectively). The results also showed that thymol displayed the maximum antifungal action against A. flavus with EC50 20 mg/L. Furthermore, the antioxidant activity was determined using N,N-dimethyl-1,4-phenylenediamine (DMPD) and the results showed that geraniol were the most potent compound (IC50 = 19 mg/L). Molecular docking studies indicated that the compounds displayed different binding interactions with the amino acid residues at the catalytic sites of N5-carboxyaminoimidazole synthetase and oxysterol binding protein Osh4 enzymes. Non-covalent interactions including van der Waals, hydrogen bonding as well as hydrophobic were observed between the compounds and the enzymes. A significant relationship was found between the docking score and the biological activity of the tested monoterpenes compared to the ceftriaxone and carbendazim as standard bactericide and fungicide, respectively. In silico ADMET properties were also performed and displayed potential for the development of promising antimicrobial agents. For these reasons, these compounds may be considered as potential ecofriendly alternatives in food preservation to delay or prevent the microbial infection and prolong the shelf life of food products.


Assuntos
Anti-Infecciosos/farmacologia , Antioxidantes/farmacologia , Monoterpenos/metabolismo , Antibacterianos/química , Antibacterianos/farmacologia , Anti-Infecciosos/química , Cicloexenos/química , Cicloexenos/farmacologia , Escherichia coli/efeitos dos fármacos , Hidrocarbonetos/química , Hidrocarbonetos/farmacologia , Testes de Sensibilidade Microbiana , Monoterpenos/química , Monoterpenos/farmacologia , Staphylococcus aureus/efeitos dos fármacos
4.
Shokuhin Eiseigaku Zasshi ; 60(3): 45-51, 2019.
Artigo em Japonês | MEDLINE | ID: mdl-31391410

RESUMO

This study aimed to survey the trend of antimicrobial resistance in Escherichia coli obtained from retail meat. We examined the susceptibilities of 1,115 E. coli isolates obtained from chicken, beef, pork, venison, and wild boar meat from 2011 to 2017 in Tokyo to 14 antimicrobials (ampicillin, cefotaxime (CTX), streptomycin, gentamicin, kanamycin, tetracycline (TC), chloramphenicol, nalidixic acid, ciprofloxacin, sulfamethoxazole-trimethoprim, fosfomycin, amikacin, imipenem, and meropenem). Of all the tested isolates, 18.7% (135/721) isolates from chicken, 77.0% (117/152) from beef, 46.6% (89/187) from pork, 100% (28/28) from venison, and 92.6% (25/27) from wild boar meat were susceptible to all tested antimicrobials. Furthermore, TC resistance was the most common, with rates as high as 56.7% (409/721) and 40.6% (76/187) in the isolates from chicken and pork, respectively. CTX resistance was detected in 4.9% (25/506) of the isolates from domestic chicken and 23.7% (51/215) of the isolates from imported chicken. Moreover, CTX resistance rate in isolates from domestic chicken was significantly lower in 2016 (0.9%, 1/111) and in 2017 (0.8%, 1/121) than in 2012 (10.6%, 17/161). In conclusion, E. coli isolates from retail meat were most commonly resistant to TC, and CTX resistance was higher in E. coli isolates from imported chicken than in E. coli isolates from domestic chicken.


Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana , Escherichia coli/efeitos dos fármacos , Microbiologia de Alimentos , Carne/microbiologia , Animais , Bovinos , Galinhas , Cervos , Testes de Sensibilidade Microbiana , Prevalência , Suínos , Tóquio
5.
World J Microbiol Biotechnol ; 35(9): 135, 2019 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-31432264

RESUMO

The feather-degrading strain Thermoactinomyces sp. YT06 secretes an extracellular keratinolytic protease (KERTYT); however, the gene encoding this protease remains unknown. The kerT1 gene (1170 bp) encoding keratinase was cloned and expressed in Escherichia coli BL21(DE3). Purified recombinant keratinase (rKERTYT) was achieved at a yield of 39.16% and 65.27-fold purification with a specific activity of 1325 U/mg. It was shown that rKERTYT has many similarities to the native enzyme (KERTYT) by characterization of rKERTYT. The molecular weight of rKERTYT secreted by recombinant E. coli was approximately 28 kDa. The optimal temperature and the pH values of rKERTYT were 65 °C and 8.5, respectively, and the protein remained stable from 50 to 60 °C and pH 6-11. The keratinase was strongly inhibited by phenyl methane sulfonyl fluoride (PMSF), suggesting that it belongs to the serine protease family. It was significantly activated by Mn2+ and ß-mercaptoethanol (ß-Me). rKERTYT showed stability and retained over 80% activity with the existence of organic solvents such as acetone, methylbenzene and dimethyl sulfoxide. These findings indicated that rKERTYT will be a promising candidate for the enzymatic processing of keratinous wastes.


Assuntos
Clonagem Molecular , Escherichia coli/metabolismo , Expressão Gênica , Peptídeo Hidrolases/genética , Peptídeo Hidrolases/metabolismo , Thermoactinomyces/enzimologia , Ativadores de Enzimas/análise , Inibidores Enzimáticos/análise , Estabilidade Enzimática , Escherichia coli/genética , Concentração de Íons de Hidrogênio , Peso Molecular , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Temperatura Ambiente , Thermoactinomyces/genética
6.
J Microbiol ; 57(9): 781-794, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31452043

RESUMO

The phytopathogenic Burkholderia species B. glumae and B. plantarii are the causal agents of bacterial wilt, grain rot, and seedling blight, which threaten the rice industry globally. Toxoflavin and tropolone are produced by these phytopathogens and are considered the most hostile biohazards with a broad spectrum of target organisms. However, despite their nonspecific toxicity, the effects of toxoflavin and tropolone on bacteria remain unknown. RNA-seq based transcriptome analysis was employed to determine the genome-wide expression patterns under phytotoxin treatment. Expression of 2327 and 830 genes was differentially changed by toxoflavin and tropolone, respectively. Enriched biological pathways reflected the down-regulation of oxidative phosphorylation and ribosome function, beginning with the inhibition of membrane biosynthesis and nitrogen metabolism under oxidative stress or iron starvation. Conversely, several systems such as bacterial chemotaxis, flagellar assembly, biofilm formation, and sulfur/taurine transporters were highly expressed as countermeasures against the phytotoxins. In addition, our findings revealed that three hub genes commonly induced by both phytotoxins function as the siderophore enterobactin, an iron-chelator. Our study provides new insights into the effects of phytotoxins on bacteria for better understanding of the interactions between phytopathogens and other microorganisms. These data will also be applied as a valuable source in subsequent applications against phytotoxins, the major virulence factor.


Assuntos
Antibacterianos/toxicidade , Burkholderia/química , Proteínas de Escherichia coli/genética , Escherichia coli/efeitos dos fármacos , Doenças das Plantas/microbiologia , Pirimidinonas/toxicidade , Triazinas/toxicidade , Tropolona/toxicidade , Antibacterianos/metabolismo , Burkholderia/metabolismo , Escherichia coli/genética , Escherichia coli/crescimento & desenvolvimento , Escherichia coli/metabolismo , Proteínas de Escherichia coli/metabolismo , Perfilação da Expressão Gênica , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Oryza/microbiologia , Pirimidinonas/metabolismo , Transcriptoma/efeitos dos fármacos , Triazinas/metabolismo , Tropolona/metabolismo
7.
Dokl Biochem Biophys ; 486(1): 206-208, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31367822

RESUMO

The aim of this work was to study the fine structure of bacterial films grown on the inner tube surface of a flow reactor. Using the scanning electron microscopy (SEM) approaches, the detailed biofilm relief was visualized. The action of electrochemically reduced water (ERW) on the biofilm ultrastructure generated by the plankton form of E. coli and/or lacto bacteria was investigated. The treatment with an ERW solution destroyed the biofilm organic polymer matrix and bacterial cells embedded in the matrix.


Assuntos
Biofilmes/efeitos dos fármacos , Água/química , Água/farmacologia , Biofilmes/crescimento & desenvolvimento , Eletroquímica , Escherichia coli/efeitos dos fármacos , Escherichia coli/fisiologia
8.
Mem. Inst. Invest. Cienc. Salud (Impr.) ; 17(2): 71-76, ago. 2019. tab, ilus
Artigo em Espanhol | LILACS, BDNPAR | ID: biblio-1008486

RESUMO

Los serogrupos O26, O45, O103, O104, O111, O121, O145 y O157 de STEC se relacionan con un elevado número de casos de SUH a nivel mundial, por lo que están incluidos dentro de las categorías de mayor riesgo para los humanos, según los criterios de autoridades alimentarias de Estados Unidos y Europa. El método convencional de identificación de antígenos O y H se realiza por aglutinación con antisueros de conejo. Este método además de ser muy costoso y laborioso, no se encuentra disponible en el país para empleo masivo. En este contexto, el objetivo de este estudio observacional descriptivo de corte transverso ha sido la estandarización de una técnica de PCR múltiple para la detección de estos 8 serogrupos, a fin de contar con un sistema de detección eficiente, sensible y con potencial de aplicación en la industria alimentaria. Se estandarizaron reacciones de PCR empleando como controles positivos cepas E. coli de referencia correspondientes a la totalidad de los serogrupos citados. Se obtuvieron productos de tamaños esperados para cada serogrupo, no se observaron amplificaciones cruzadas o falsos positivos. Esta técnica estandarizada podría representar una herramienta rápida y menos costosa que la técnica serológica, con la capacidad de ser aplicada a diferentes matrices, permitiendo la detección de estos serogrupos en aislados STEC de ganado en pie, fuentes de agua de consumo, alimentos e incluso en aislamientos clínicos asociados a enfermedades humanas(AU)


STEC serogroups O26, O45, O103, O104, O111, O121, O145, and O157, are related to a high number of cases of HUS worldwide, so they are included in the categories of greatest risk for humans, according to the food administration criteria of the United States and Europe. The conventional method of identifying antigens O and H is carried out by agglutination with rabbit antisera. This method is very expensive and laborious and is not available in the country for massive-scale use. In this context, the objective of this cross-sectional descriptive observational study has been the standardization of a multiplex PCR technique for the detection of these 8 serogroups, in order to have an efficient and sensitive detection system with the potential for application in the food industry. PCR reactions were standardized using as positive controls reference E. coli strains to correspond to all the mentioned serogroups. Products of expected sizes were obtained for each serogroup; no cross-amplification or false positives were observed. This standardized technique could represent a quick and less expensive tool than the serological technique, with the possibility to be applied to different kind of samples, allowing the detection of these serogroups in STEC isolates of live cattle, sources of drinking water, food and even in clinical isolates associated with human diseases(AU)


Assuntos
Animais , Toxina Shiga , Escherichia coli , Reação em Cadeia da Polimerase Multiplex
9.
J Enzyme Inhib Med Chem ; 34(1): 1439-1450, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31409157

RESUMO

Leishmaniasis is a tropical disease found in more than 90 countries. The drugs available to treat this disease have nonspecific action and high toxicity. In order to develop novel therapeutic alternatives to fight this ailment, pteridine reductase 1 (PTR1) and dihydrofolate reductase-thymidylate synthase (DHF-TS) have been targeted, once Leishmania is auxotrophic for folates. Although PTR1 and DHFR-TS from other protozoan parasites have been studied, their homologs in Leishmania chagasi have been poorly characterized. Hence, this work describes the optimal conditions to express the recombinant LcPTR1 and LcDHFR-TS enzymes, as well as balanced assay conditions for screening. Last but not the least, we show that 2,4 diaminopyrimidine derivatives are low-micromolar competitive inhibitors of both enzymes (LcPTR1 Ki = 1.50-2.30 µM and LcDHFR Ki = 0.28-3.00 µM) with poor selectivity index. On the other hand, compound 5 (2,4-diaminoquinazoline derivative) is a selective LcPTR1 inhibitor (Ki = 0.47 µM, selectivity index = 20).


Assuntos
Inibidores Enzimáticos/farmacologia , Leishmania infantum/enzimologia , Complexos Multienzimáticos/antagonistas & inibidores , Oxirredutases/antagonistas & inibidores , Timidilato Sintase/antagonistas & inibidores , Catálise , Cromatografia de Afinidade , Clonagem Molecular , Avaliação Pré-Clínica de Medicamentos , Eletroforese em Gel de Poliacrilamida , Escherichia coli/genética , Concentração Inibidora 50 , Complexos Multienzimáticos/genética , Complexos Multienzimáticos/isolamento & purificação , Complexos Multienzimáticos/metabolismo , Oxirredutases/genética , Oxirredutases/isolamento & purificação , Oxirredutases/metabolismo , Tetra-Hidrofolato Desidrogenase/genética , Tetra-Hidrofolato Desidrogenase/isolamento & purificação , Tetra-Hidrofolato Desidrogenase/metabolismo , Timidilato Sintase/genética , Timidilato Sintase/isolamento & purificação , Timidilato Sintase/metabolismo
10.
Zhonghua Yi Xue Za Zhi ; 99(30): 2355-2361, 2019 Aug 13.
Artigo em Chinês | MEDLINE | ID: mdl-31434416

RESUMO

Objective: To investigate the role of actin-related protein 2-3 complex (Arp2/3) complex on phagocytosis of alveolar macrophages (AMs) in a mouse model of chronic obstructive pulmonary (COPD). Methods: Forty mice were randomly divided into healthy control group, healthy Arp2/3 complex inhibitor (CK666) group, COPD group and COPD CK666 group with 10 mice in each group. COPD group and COPD CK666 group were established by cigarette smoke exposure, and the control group had no smoke exposure. After 90 days of molding, AMs were isolated from lung tissue of mice in each group. Mean fluorescence intensity (MFI) and the positive percent of AMs engulfing fluorescein isothiocyanate-labeled Escherchina coli (FITC-E.coli) (AM%) were detected by flow cytometry. Western blot was applied to detect protein. Laser scanning confocal microscopy was used to measure the mean optical density of Arp2, F-actin and engulfed FITC-E. coli and quantify the colocalization of Arp2 and F-actin by a Manders' overlap coefficient. Scanning electron microscopy was used to observe the ultrastructure of AM phagocytizing FITC-E.coli. Results: Phagocytosis of AM: MFI and AM% in the COPD group were significantly decreased than those in the healthy control group[(4 702±243), (8 684±234) and (32.21±1.66)%, (65.88±1.77)%, all P<0.01]. MFI and AM% in the COPD CK666 group [(3 597±307), (22.09±1.89)%] and in the healthy CK666 group [(7 446±236), (50.09±1.64)%] were decreased compared to those in their respective control groups (all P<0.01). The expressions of protein of Arp2 and F-actin in the COPD group were significantly decreased than those in the healthy control group (0.508±0.025, 0.813±0.040 and 0.462±0.029, 0.720±0.039) (all P<0.01). The F-actin in the COPD CK666 group (0.265±0.014) and in the healthy CK666 group (0.637±0.032) were significantly decreased compared to those in their respective control groups (all P<0.01). The mean optical density of Arp2, F-actin and FITC-E.coli in the COPD group were significantly decreased compared to those in the healthy group (34.43±0.56, 142.83±1.90 and 61.59±0.70, 145.93±3.05 and 41.49±0.33, 189.17±2.60) (all P<0.01); the mean optical density of F-actin, FITC-E. coli in the COPD CK666 group (37.73±1.04, 28.84±2.95) and in the healthy CK666 group (137.07±1.35, 157.46±1.00) were significantly decreased compared to those in their respective control groups (all P<0.01). The Manders' overlap coefficient of Arp2 and phalloidin' coefficient in the COPD group (0.395±0.014) were significantly decreased than the healthy control group (0.395±0.014 and 0.880±0.002, P<0.01). The Manders' overlap coefficient of Arp2 and phalloidin' coefficient in the COPD CK666 group (0.297±0.006) and in the healthy CK666 group (0.737±0.031) were significantly decreased compared to those in their respective control groups (all P<0.01). Shape of AM: Long filopodia protruding and plentiful dorsal ruffle can be seen in AM from the healthy control group; AM pseudopods extension and dorsal ruffle reduced in the health CK666 group; there were pseudopods and dorsal ruffle defects in the COPD group and the COPD CK666 group. Positive correlations existed between the proteins of Arp2, F-actin with MFI. Positive correlations also existed between the Manders' overlap coefficient of Arp2 and phalloidin' coefficient with MFI. Conclusion: Decreased activity of Arp2/3 complex leads to low phagocytosis of AM in COPD mice, and AM in COPD mice is more sensitive to Arp2/3 complex inhibitor.


Assuntos
Macrófagos Alveolares , Doença Pulmonar Obstrutiva Crônica , Complexo 2-3 de Proteínas Relacionadas à Actina , Animais , Escherichia coli , Camundongos , Fagocitose
11.
World J Microbiol Biotechnol ; 35(7): 106, 2019 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-31267229

RESUMO

Xenorhabdus nematophila HB310 secreted the insecticidal protein toxin complex. Two chitinase genes, chi60 and chi70, were found in X. nematophila toxin complex locus. In order to clarify the function of two chitinases, chi60 and chi70 genes were cloned and expressed in Escherichia coli Transetta (DE3). As a result, we found that the Chi60 and Chi70 belonged to glycoside hydrolases (GH) family 18 with a molecular mass of 65 kDa and 78 kDa, respectively. When colloidal chitin was treated as the substrate, Chi60 and Chi70 were proved to have the highest enzymatic activity at pH 6.0 and 50 °C. Chi60 and Chi70 had obvious growth inhibition effect against the second larvae of Helicoverpa armigera with growth inhibiting rate of 81.99% and 90.51%. Chi70 had synergistic effect with the insecticidal toxicity of Bt Cry 1Ac, but the Chi60 had no synergistic effect with Bt Cry 1Ac. Chi60 and Chi70 showed antifungal activity against Alternaria brassicicola, Verticillium dahliae and Coniothyrium diplodiella. The results increased our understanding of the chitinases produced by X. nematophila and laid a foundation for further studies on the mechanism of the chitinases.


Assuntos
Antifúngicos/farmacologia , Quitinases/antagonistas & inibidores , Quitinases/genética , Quitinases/metabolismo , Xenorhabdus/metabolismo , Alternaria/efeitos dos fármacos , Animais , Ascomicetos/efeitos dos fármacos , Quitina/metabolismo , Quitinases/classificação , Clonagem Molecular , Sinergismo Farmacológico , Ensaios Enzimáticos , Estabilidade Enzimática , Escherichia coli/genética , Expressão Gênica , Glicosídeo Hidrolases/genética , Concentração de Íons de Hidrogênio , Inseticidas/metabolismo , Inseticidas/farmacologia , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Peso Molecular , Mariposas/efeitos dos fármacos , Mariposas/crescimento & desenvolvimento , Micotoxinas/genética , Micotoxinas/metabolismo , Filogenia , Domínios Proteicos , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Temperatura Ambiente , Verticillium/efeitos dos fármacos , Xenorhabdus/genética
13.
BMC Vet Res ; 15(1): 268, 2019 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-31357996

RESUMO

BACKGROUND: This study investigated changes over time in the epidemiology of extended-spectrum ß-lactamase (ESBL) producing Escherichia coli within a single equine referral hospital in the UK. Faecal samples were collected from hospitalised horses in 2008 and 2017, processed using selective media and standard susceptibility laboratory methods. A novel real-time PCR with high resolution melt analysis was used to distinguish blaCTX-M-1 and blaCTX-M-15 within CTX-M-1 group. RESULTS: In 2008, 457 faecal samples from 103 horses were collected, with ESBL-producing E. coli identified in 131 samples (28.7, 95% CI 24.6-33.1). In 2017, 314 faecal samples were collected from 74 horses with ESBL-producing E. coli identified in 157 samples (50.0, 95% CI 44.5-55.5). There were 135 and 187 non-duplicate ESBL-producing isolates from 2008 and 2017, respectively. In 2008, 12.6% of isolates belonged to CTX-M-1 group, all carrying blaCTX-M-1, whilst in 2017, 94.1% of isolates were CTX-M-1 group positive and of these 39.2 and 60.8% of isolates carried blaCTX-M-1 and blaCTX-M-15, respectively. In addition, the prevalence of doxycycline, gentamicin and 3rd generation cephalosporin resistance increased significantly from 2008 to 2017 while a decreased prevalence of phenotypic resistance to potentiated sulphonamides was observed. CONCLUSIONS: The real-time PCR proved a reliable and high throughput method to distinguish between blaCTX-M-1 and blaCTX-M-15. Furthermore, its use in this study demonstrated the emergence of faecal carriage of CTX-M-15 in hospitalised horses, with an increase in prevalence of ESBL-producing E. coli as well as increased antimicrobial resistance to frequently used antimicrobials.


Assuntos
Infecções por Escherichia coli/veterinária , Fezes/microbiologia , Doenças dos Cavalos/epidemiologia , Doenças dos Cavalos/microbiologia , beta-Lactamases/metabolismo , Animais , Antibacterianos/farmacologia , Farmacorresistência Bacteriana , Escherichia coli/efeitos dos fármacos , Escherichia coli/enzimologia , Escherichia coli/genética , Infecções por Escherichia coli/epidemiologia , Infecções por Escherichia coli/microbiologia , Cavalos , Hospitais Veterinários/estatística & dados numéricos , Prevalência , Reino Unido/epidemiologia , beta-Lactamases/genética
14.
Sheng Wu Gong Cheng Xue Bao ; 35(7): 1247-1255, 2019 Jul 25.
Artigo em Chinês | MEDLINE | ID: mdl-31328481

RESUMO

L-tyrosine is one of three aromatic amino acids that are widely used in food, pharmaceutical and chemical industries. The transport system engineering provides an important research strategy for the metabolic engineering of Escherichia coli to breed L-tyrosine producing strain. The intracellular transport of L-tyrosine in E. coli is mainly regulated by two distinct permeases encoded by aroP and tyrP genes. The aroP and tyrP gene knockout mutants were constructed by CRISPR-Cas technique on the basis of L-tyrosine producing strain HGXP, and the effects of regulating transport system on L-tyrosine production were investigated by fermentation experiments. The fermentation results showed that the aroP and tyrP knockout mutants produced 3.74 and 3.45 g/L L-tyrosine, respectively, which were 19% and 10% higher than that of the original strain. The optimum induction temperature was determined to be 38 °C. Fed-batch fermentation was carried out on a 3-L fermentor. The L-tyrosine yields of aroP and tyrP knockout mutants were further increased to 44.5 and 35.1 g/L, respectively, which were 57% and 24% higher than that of the original strain. The research results are of great reference value for metabolic engineering of E. coli to produce L-tyrosine.


Assuntos
Escherichia coli , Proteínas de Escherichia coli , Técnicas de Inativação de Genes , Engenharia Metabólica , Tirosina
15.
Sheng Wu Gong Cheng Xue Bao ; 35(7): 1286-1294, 2019 Jul 25.
Artigo em Chinês | MEDLINE | ID: mdl-31328485

RESUMO

Biogenic amines (BAs) are low molecular weight organic compounds that present in fermented foods. Large amount of ingested biogenic amines can cause allergy or significant symptoms. Reduction of BAs by enzymatic reaction in fermented foods is one of the most efficient methods for removal of biohazard compounds and assurance food safety. In this study, the multicopper oxidase (MCO) gene in the genome of Lactobacillus fermentum was successfully cloned in Escherichia coli BL21 and expressed at 484 U/L. The recombinant MCO was purified by the immobilized metal affinity chromatography method. The optimal reaction temperature and pH for this enzyme was detected to be 50 °C and 3.5. The Km and Vmax values of the recombinant MCO was determined to be 1.30 mmol/L and 7.67×10⁻² mmol/(L·min). Moreover, this MCO dramatically degrades histamine and tyramine by 51.6% and 40.9%, and can degrade other BAs including tryptamine, phenylethylamine, putrescine, cadaverine and spermidine, and was found to be tolerant to 18% (W/V) NaCl. The recombinant MCO is also capable of degrading BAs in soy sauce. The degradation rate of total BAs in soy sauce reaches 10.6% though a relatively low level of enzyme (500 U/L) is used. Multicopper oxidase has the potential to degrade biogenic amines in fermented foods, which lays a foundation for the further application of this kind of food enzymes.


Assuntos
Lactobacillus fermentum , Aminas Biogênicas , Cadaverina , Escherichia coli , Oxirredutases
16.
Sheng Wu Gong Cheng Xue Bao ; 35(7): 1348-1358, 2019 Jul 25.
Artigo em Chinês | MEDLINE | ID: mdl-31328491

RESUMO

The trehalose synthase (ScTreS) gene from Streptomyces coelicolor was successfully cloned and heterologously expressed in Escherichia coli BL21(DE3). The protein purified by Ni-NTA affinity column showed an apparent molecular weight (MW) of 62.3 kDa analyzed by SDS-PAGE. The optimum temperature of the enzyme was 35 °C and the optimum pH was 7.0; the enzyme was sensitive to acidic conditions. By homologous modeling and sequence alignment, the enzyme was modified by site-directed mutagenesis. The relative activities of the mutant enzymes K246A and A165T were 1.43 and 1.39 times that of the wild type, an increased conversion rate of 14% and 10% respectively. To optimize the synthesis conditions of trehalose, the mutant strain K246A was cultivated in a 5-L fermentor and used for whole-cell transformation. The results showed that with the substrate maltose concentration of 300 g/L at 35 °C and pH 7.0, the highest conversion rate reached 71.3%, and the yield of trehalose was 213.93 g/L. However, when maltose concentration was increased to 700 g/L, the yield of trehalose can reach 465.98 g/L with a conversion rate of 66%.


Assuntos
Streptomyces coelicolor , Biocatálise , Clonagem Molecular , Escherichia coli , Glucosiltransferases , Trealose
17.
Pol Merkur Lekarski ; 46(276): 233-238, 2019 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-31260430

RESUMO

Proteinuria accompanies kidney diseases of various etiology and correlates with the degree of organ damage. Analysis of proteinuria allows the location of pathophysiological process in the kidney, and assessment of the severity of the kidney disease in chronic and acute kidney injury (AKI). Ascending bacterial acute kidney injury develops as a consequence of pyelonephritis. It is a rare complication in patients with anatomical or functional dysfunctions of the urinary tract. AIM: The aim of the study was to perform the laboratory analysis of proteinuria in bacterial ascending AKI in an experimental model. MATERIALS AND METHODS: Female Wistar rats (n = 24) were intravesically administrated bacterial suspension of Escherichia coli (E. coli) to induce: pyelonephritis (group 1, 105 CFU/ml); AKI (group 2, 107 CFU/ml); AKI and urosepsis (group 3, 109 CFU/ml) respectively. Bacterial strain - E.coli, was isolated from a patient with acute pyelonephritis. The daily diuresis and urine protein excretion was measured the following days: 0, 7, 14 and 21. Moreover, electrophoretic separation of urine protein, densitometric analysis of albumin fraction and uromodulin concentration in urine were performed. Moreover, the key parameters for the diagnosis of AKI were assayed. RESULTS: Increased urinary protein excretion was observed in each of the study groups. Moreover, the study groups showed significant changes in protein selectivity in the urine. CONCLUSIONS: Moderately severe proteinuria was revealed while its selectivity suggested significant damage of glomeruli and renal tubules in groups with complications caused by AKI induced by ascending pyelonephritis.


Assuntos
Lesão Renal Aguda , Escherichia coli , Proteinúria , Animais , Feminino , Humanos , Rim , Modelos Teóricos , Ratos , Ratos Wistar
18.
J Insect Sci ; 19(4)2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-31343690

RESUMO

Bombyx mori (Lepidoptera: Bombycidae) is an important economic insect and a classic Lepidopteran model system. Although immune-related genes have been identified at a genome-wide scale in the silkworm, proteins involved in immune defense of the silkworm have not been comprehensively characterized. In this study, two types of bacteria were injected into the silkworm larvae, Gram-negative Escherichia coli (Enterobacteriales: Enterobacteriaceae), or Gram-positive Staphylococcus aureus (Bacillales: Staphylococcaceae). After injection, proteomic analyses of hemolymph were performed by liquid chromatography-tandem mass spectrometry. In total, 514 proteins were identified in the uninduced control group, 540 were identified in the E. coli-induced group, and 537 were identified in the S. aureus-induced group. Based on Uniprot annotations, 32 immunological recognition proteins, 28 immunological signaling proteins, and 21 immunological effector proteins were identified. We found that 127 proteins showed significant upregulation, including 10 immunological recognition proteins, 4 immunological signaling proteins, 11 immunological effector proteins, and 102 other proteins. Using real-time quantitative polymerase chain reaction in the fat body, we verified that immunological recognition proteins, signaling proteins, and effector proteins also showed significant increases at the transcriptional level after infection with E. coli and S. aureus. Five newly identified proteins showed upregulation at both protein and transcription levels after infection, including 30K protein, yellow-d protein, chemosensory protein, and two uncharacterized proteins. This study identified many new immune-related proteins, deepening our understanding of the immune defense system in B. mori. The data have been deposited to the iProX with identifier IPX0001337000.


Assuntos
Bombyx/genética , Bombyx/imunologia , Escherichia coli/fisiologia , Proteínas de Insetos/imunologia , Proteoma/imunologia , Staphylococcus aureus/fisiologia , Animais , Bombyx/crescimento & desenvolvimento , Bombyx/microbiologia , Proteínas de Insetos/análise , Larva/crescimento & desenvolvimento , Larva/imunologia , Larva/microbiologia , Proteoma/análise , Proteômica
19.
J Agric Food Chem ; 67(31): 8581-8589, 2019 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-31321975

RESUMO

Intermediates in aromatic amino acid biosynthesis can serve as substrates for the synthesis of bioactive compounds. In this study we used two intermediates in the shikimate pathway of Escherichia coli, chorismate and anthranilate, to synthesize three bioactive compounds: 4-hydroxycoumarin (4-HC), 2,4-dihydroxyquinoline (DHQ), and 4-hydroxy-1-methyl-2(1H)-quinolone (NMQ). We introduced genes for the synthesis of salicylic acid from chorismate to supply the substrate for 4-HC and the gene encoding N-methyltransferase for the synthesis of N-methylanthranilate from anthranilate. Polyketide synthases and coenzyme (Co)A ligases were tested to determine the optimal combination of genes for the synthesis of each compound. We also tested several constructs and identified the best one for increasing levels of endogenous substrates for chorismate, anthranilate, and malonyl-CoA. With the use of these strategies, 255.4 mg/L 4-HC, 753.7 mg/L DHQ, and 17.5 mg/L NMQ were synthesized. This work provides a basis for the synthesis of diverse coumarin and quinoline derivatives with potential medical applications.


Assuntos
4-Hidroxicumarinas/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Engenharia Metabólica , Policetídeo Sintases/genética , Quinolinas/metabolismo , 4-Hidroxicumarinas/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Ácido Corísmico/metabolismo , Coenzima A Ligases/genética , Coenzima A Ligases/metabolismo , Photorhabdus/enzimologia , Photorhabdus/genética , Policetídeo Sintases/metabolismo , Pseudomonas aeruginosa/enzimologia , Pseudomonas aeruginosa/genética , Quinolinas/química , ortoaminobenzoatos/metabolismo
20.
Zhonghua Er Ke Za Zhi ; 57(7): 553-558, 2019 Jul 02.
Artigo em Chinês | MEDLINE | ID: mdl-31269557

RESUMO

Objective: Analyze the changes of indicator of antimicrobial usage and detection rate of multidrug-resistant gram-negative bacteria (MDR-GNB), in order to evaluate the impact of antimicrobial stewardship program (ASP). Methods: The antimicrobial stewardship program was implemented since December 2011 at the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University. Intensified effort was made from 2014 to 2017. We divided the program into four stages, one before ASP (2010-2011) and three after ASP (2012-2013 as the first, 2014-2015 as the second and 2016-2017 as the third post-ASP stages). The usage rates in outpatient,emergency department and inpatient, along with the antibiotic use density (AUD, defined as daily doses/per 100 patient-days), the AUD of the third-generation cephalosporins and carbapenems in inpatient were reviewed retrospectively. The detection rates of extended-spectrum ß-lactamases (ESBLs)-producing Escherichia coli, ESBLs-producing Klebsiella pneumonia, carbapenem-resistant E. coli, carbapenem-resistant Klebsiella pneumonia, carbapenem-resistant Acinetobacter baumannii and carbapenem-resistant Pseudomonas aeruginosa were also analyzed at the same time. The correlation analysis between the detection rate of MDR-GNB and the indicator of antimicrobial usage was made. Result: Among four stages, the usage rates were 55.2% (560 578/1 015 540) , 38.1% (493 554/1 296 336) , 26.8% (378 602/1 411 595) and 23.1% (347 817/1 502 817) in outpatient, 75.6% (429 582/568 230) , 61.4% (382 558/623 138) , 43.6% (265 102/608 071) and 35.1% (218 484/622 397) in emergency department, and 76.0% (30 568/40 221) , 53.7% (30 437/56 636) , 49.9% (37 395/74 895) and 50.3% (35 493/70 544) in inpatient, respectively. All indicators decreased significantly (χ(2)=297 811.798, 3 155 704.783, 5 592.037, P<0.01). The AUD in inpatient was 38.4,31.8,21.7 and 19.41,and the AUD of the third-generation cephalosporins were 13.83, 11.21, 6.20 and 6.84, respectively, which decreased significantly after ASP (r=-0.878, -0.781, P<0.05). The AUD of carbapenems were 1.94,1.77,1.87 and 1.93, respectively (r=0.123, P>0.05). A total of 11 289 strains of bacteria were collected, including 5 589 strains of E. coli, 2 823 strains of K.pneumoniae, 1 637 strains of A. baumandii, and 1 240 strains of P. aeruginosa.The detection rates of ESBLs-producing E.coli and ESBLs -producing K. pneumoniae in four stages were 75.4% (1 034/1 371) , 66.6% (893/1 341) , 57.8% (834/1 443) , 46.7% (670/1 434) and 78.7% (547/695) , 67.5% (455/674) , 49.3% (421/854) , 32.5% (195/600) , respectively,both decreased significantly (χ(2)=266.204; 328.805, P<0.01). The detection rates of Carbapenem-resistant A. baumannii were 28.2% (115/408) , 26.7% (126/472) , 24.3% (125/515) and 12.0% (29/242) respectively,and showed significant decreasing trend after ASP (χ(2)=18.112, P<0.01). The detection rates of carbapenem-resistant P. aeruginosa were 11.3% (40/355) , 18.5% (58/313) , 13.4% (46/343) and 7.0% (16/229) , respectively,with the most obvious decrease in the third stage after ASP. The detection rates of carbapenem-resistant E. coli and carbapenem-resistant K. pneumonia were continuously lower (<5%). There were positive correlations between the detection rates of ESBLs-producing E. coli and K. pneumoniae and all usage indicators (r(1)=0.930, 0.974, 0.746, 0.958, 0.842; r(2)=0.910, 0.960, 0.765, 0.963, 0.898, P<0.05). Conclusion: The antimicrobial stewardship program can effectively reduce both the usage of antimicrobial and the production of MDR-GNB, which has great value to promote rational clinical use of antimicrobials and reduce bacterial resistance.


Assuntos
Antibacterianos/farmacologia , Gestão de Antimicrobianos , Bactérias Gram-Negativas/efeitos dos fármacos , Infecções por Bactérias Gram-Negativas/tratamento farmacológico , Criança , Farmacorresistência Bacteriana , Escherichia coli , Bactérias Gram-Negativas/isolamento & purificação , Infecções por Bactérias Gram-Negativas/microbiologia , Humanos , Testes de Sensibilidade Microbiana , Avaliação de Programas e Projetos de Saúde , Estudos Retrospectivos
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