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1.
Talanta ; 233: 122535, 2021 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-34215038

RESUMEN

Bacterial infection poses a serious threat to human health worldwide. Rapid antimicrobial susceptibility testing (AST) is essential for the clinical treatment of bacterial infection patients. However, the traditional AST relies on bacteria culture, which is time-consuming and limits the analysis to culturable species. Herein, we present a laser desorption ionization (LDI) mass spectrometry-based method for rapid bacterial viability assessment and AST by tracing the redox of resazurin (RS) by viable bacteria. RS as well as its reduction product, fluorescent resorufin (RF), can be directly detected by LDI-MS in the absence of matrix. The intensity ratio between RF and RS can be used to assess the viability of bacteria in specimens. We have demonstrated the high efficiency of the method using different bacterial species, including K. pneumoniae, S. aureus, E. coli, and P. aeruginosa, and various antibiotic drugs, such as ciprofloxacin, ampicillin, tetracycline, oxytetracycline, ciprofloxacin and levofloxacin. Compared to traditional methods based on optical absorption, the current method is faster and more sensitive. Furthermore, we applied the method to bacterial viability detection and AST using human body fluid samples, i.e. serum and urine, demonstrating that it can screen rapidly appropriate antibiotic drugs for timely clinical treatment of infectious diseases. With the advantages of simplicity in methodology as well as sensitivity and speed in analysis, the current method holds the potential of clinical usages.


Asunto(s)
Escherichia coli , Staphylococcus aureus , Antibacterianos/farmacología , Humanos , Rayos Láser , Pruebas de Sensibilidad Microbiana , Viabilidad Microbiana , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción
2.
Talanta ; 233: 122610, 2021 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-34215094

RESUMEN

Recently, antibiotic resistant has become a serious public health concern, which warrants new generations of antibiotics to be developed. Pharmacodynamic evaluation is crucial in drug discovery processes. Despite numerous advanced imaging systems are available nowadays, technologies for the sensitive in vivo diagnosis of bacterial infections and direct visualization of drug efficacy are yet to be developed. In this study, we have developed novel near-infrared (NIR) fluorogenic probes. These probes are dark in solution but highly fluorescent when bound to the cognate reporter, fluorogen-activating protein (FAP). We established the in vivo bacterial infection model using FAP_dH6.2 recombinantly expressed E. coli and applied this NIR fluoromodule-based system for diagnosing bacterial infections and monitoring disease progressions and its responses to a type of antibiotics through classic mechanism of membrane lysis. This NIR fluoromodule-based system will discover new information on bacterial infections and identify newer antibacterial entities.


Asunto(s)
Infecciones Bacterianas , Colorantes Fluorescentes , Antibacterianos/farmacología , Infecciones Bacterianas/diagnóstico , Infecciones Bacterianas/tratamiento farmacológico , Escherichia coli/genética , Humanos , Proteínas
3.
Mymensingh Med J ; 30(3): 718-724, 2021 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-34226461

RESUMEN

Urinary tract infection (UTI) is a common complication in nephrotic children and leads to most morbidity and mortality in developing countries like Bangladesh. This case control study was conducted in the Department of Pediatrics and Pediatric Nephrology ward of Dhaka Medical College Hospital, Dhaka from July 2016 to June 2018 to identify the risk factors of UTI in children with nephrotic syndrome. Total 90 patient of nephrotic children aged 2-12 years, who were fulfilling the inclusion and exclusion criteria were selected as Group I (case) and Group II (control) according to urine culture report. Group I was UTI positive and Group II was UTI negative. The mean age of Group I was 5.26±3.18 years and Group II was 6.03±2.85 years. There was male predominance in both groups. No significant difference has been found regarding age and sex (p>0.05). No significant difference was also observed regarding economic status and educational level of mother among both groups (p>0.05). Fever, dysuria, abdominal pain, anasarca, vomiting and pallor were found as common presentations in Group I. Children with dysuria and abdominal pain were significantly higher in Group I than Group II (p value <0.001). UTI was found more in relapsed cases than initial attack. E. coli was the most common etiologic agent (37.8%). Mean Hb (gm/dl), serum total protein, serum albumin and serum IgG level were found significantly lower and spot urine protein creatinine ratio was significantly higher in Group I, which implies that those biochemical factors were associated with development of UTI in nephrotic children. Younger age group (<6 years), Constipation and uncircumcised male were found as risk factors and has association with UTI in nephrotic children.


Asunto(s)
Síndrome Nefrótico , Infecciones Urinarias , Bangladesh/epidemiología , Estudios de Casos y Controles , Niño , Preescolar , Escherichia coli , Humanos , Lactante , Masculino , Síndrome Nefrótico/complicaciones , Síndrome Nefrótico/epidemiología , Factores de Riesgo , Infecciones Urinarias/epidemiología , Infecciones Urinarias/etiología
4.
Sheng Wu Gong Cheng Xue Bao ; 37(6): 2077-2084, 2021 Jun 25.
Artículo en Chino | MEDLINE | ID: mdl-34227295

RESUMEN

Curcumin is exclusively isolated from Zingiberaceae plants with a broad spectrum of bioactivities. In the present study, we used the diketide-CoA synthase (DCS) and curcumin synthase (CURS) genes to construct a non-natural fusion gene encoding diketide-CoA synthase::curcumin synthase (DCS::CURS). This fusion protein, together with the acetyl coenzyme A carboxylase (ACC) and the 4-coumarate coenzyme A ligase (4CL), were introduced into Escherichia coli for the production of curcumin from ferulic acid. The process is divided into two stages, the growth stage using LB medium and the fermentation stage using the modified M9 medium. The yield of curcumin reached 386.8 mg/L by optimizing the induction of protein expression in the growth stage, and optimizing the inoculum volume, medium composition and fermentation time in the fermentation stage, as well as the addition of macroporous resin AB-8 into the second medium to attenuate the toxicity of the end product. The exploitation of the non-natural fusion protein DCS::CURS for the production of curcumin provides a new alternative to further promoting the production of curcumin and the related analogues.


Asunto(s)
Curcumina , Escherichia coli , Curcumina/farmacología , Escherichia coli/genética , Fermentación
5.
Molecules ; 26(13)2021 Jun 28.
Artículo en Inglés | MEDLINE | ID: mdl-34203222

RESUMEN

The effect of cultivation temperatures (37, 26, and 18 °C) on the conformational quality of Yersinia pseudotuberculosis phospholipase A1 (PldA) in inclusion bodies (IBs) was studied using green fluorescent protein (GFP) as a folding reporter. GFP was fused to the C-terminus of PldA to form the PldA-GFP chimeric protein. It was found that the maximum level of fluorescence and expression of the chimeric protein is observed in cells grown at 18 °C, while at 37 °C no formation of fluorescently active forms of PldA-GFP occurs. The size, stability in denaturant solutions, and enzymatic and biological activity of PldA-GFP IBs expressed at 18 °C, as well as the secondary structure and arrangement of protein molecules inside the IBs, were studied. Solubilization of the chimeric protein from IBs in urea and SDS is accompanied by its denaturation. The obtained data show the structural heterogeneity of PldA-GFP IBs. It can be assumed that compactly packed, properly folded, proteolytic resistant, and structurally less organized, susceptible to proteolysis polypeptides can coexist in PldA-GFP IBs. The use of GFP as a fusion partner improves the conformational quality of PldA, but negatively affects its enzymatic activity. The PldA-GFP IBs are not toxic to eukaryotic cells and have the property to penetrate neuroblastoma cells. Data presented in the work show that the GFP-marker can be useful not only as target protein folding indicator, but also as a tool for studying the molecular organization of IBs, their morphology, and localization in E. coli, as well as for visualization of IBs interactions with eukaryotic cells.


Asunto(s)
Proteínas Bacterianas/química , Proteínas Fluorescentes Verdes/química , Cuerpos de Inclusión/química , Fosfolipasas A1/química , Proteínas Recombinantes de Fusión/química , Yersinia pseudotuberculosis/genética , Proteínas Bacterianas/biosíntesis , Proteínas Bacterianas/genética , Escherichia coli/genética , Escherichia coli/metabolismo , Proteínas Fluorescentes Verdes/biosíntesis , Proteínas Fluorescentes Verdes/genética , Cuerpos de Inclusión/genética , Cuerpos de Inclusión/metabolismo , Fosfolipasas A1/biosíntesis , Fosfolipasas A1/genética , Proteínas Recombinantes de Fusión/biosíntesis , Proteínas Recombinantes de Fusión/genética , Yersinia pseudotuberculosis/enzimología
6.
BMC Plant Biol ; 21(1): 319, 2021 Jul 03.
Artículo en Inglés | MEDLINE | ID: mdl-34217205

RESUMEN

BACKGROUND: PTI1 (Pto-interacting 1) protein kinase belongs to the receptor-like cytoplasmic kinase (RLCK) group of receptor-like protein kinases (RLK), but lack extracellular and transmembrane domains. PTI1 was first identified in tomato (Solanum lycopersicum) and named SlPTI1, which has been reported to interact with bacterial effector Pto, a serine/threonine protein kinase involved in plant resistance to bacterial disease. Briefly, the host PTI1 specifically recognizes and interacts with the bacterial effector AvrPto, which triggers hypersensitive cell death to inhibit the pathogen growth in the local infection site. Previous studies have demonstrated that PTI1 is associated with oxidative stress and hypersensitivity. RESULTS: We identified 12 putative PTI1 genes from the genome of foxtail millet (Setaria italica) in this study. Gene replication analysis indicated that both segmental replication events played an important role in the expansion of PTI1 gene family in foxtail millet. The PTI1 family members of model plants, i.e. S. italica, Arabidopsis (Arabidopsis thaliana), rice (Oryza sativa), maize (Zea mays), S. lycopersicum, and soybean (Glycine max), were classified into six major categories according to the phylogenetic analysis, among which the PTI1 family members in foxtail millet showed higher degree of homology with those of rice and maize. The analysis of a complete set of SiPTI1 genes/proteins including classification, chromosomal location, orthologous relationships and duplication. The tissue expression characteristics revealed that SiPTI1 genes are mainly expressed in stems and leaves. Experimental qRT-PCR results demonstrated that 12 SiPTI1 genes were induced by multiple stresses. Subcellular localization visualized that all of foxtail millet SiPTI1s were localized to the plasma membrane. Additionally, heterologous expression of SiPTI1-5 in yeast and E. coli enhanced their tolerance to salt stress. CONCLUSIONS: Our results contribute to a more comprehensive understanding of the roles of PTI1 protein kinases and will be useful in prioritizing particular PTI1 for future functional validation studies in foxtail millet.


Asunto(s)
Genoma de Planta , Familia de Multigenes , Proteínas de Plantas/genética , Salinidad , Setaria (Planta)/genética , Setaria (Planta)/fisiología , Cromosomas de las Plantas/genética , Escherichia coli/metabolismo , Duplicación de Gen/genética , Regulación de la Expresión Génica de las Plantas , Genes de Plantas , Anotación de Secuencia Molecular , Motivos de Nucleótidos/genética , Filogenia , Proteínas de Plantas/metabolismo , Saccharomyces cerevisiae/metabolismo , Estrés Fisiológico/genética , Sintenía/genética
7.
J Agric Food Chem ; 69(27): 7572-7580, 2021 Jul 14.
Artículo en Inglés | MEDLINE | ID: mdl-34196182

RESUMEN

As a natural sesquiterpene compound with numerous biological activities, patchoulol has extensive applications in the cosmetic industry and potential usage in pharmaceuticals. Although several patchoulol-producing microbial strains have been constructed, the low productivity still hampers large-scale fermentation. Escherichia coli possesses the ease of genetic manipulation and simple nutritional requirements and does not comprise competing pathways for the farnesyl diphosphate (FPP) precursor, showing its potential for patchoulol biosynthesis. Here, combinatorial strategies were applied to produce patchoulol in E. coli. The initial strain was constructed, and it produced 14 mg/L patchoulol after fermentation optimization. Patchoulol synthase (PTS) was engineered by semirational design, resulting in improved substrate binding affinity and a patchoulol titer of 40.3 mg/L; the patchoulol titer reached 66.2 mg/L after fusing of PTS with FPP synthase. To further improve the patchoulol production, the genome of an efficient chassis strain was engineered by deleting the competitive routes for acetate, lactate, ethanol, and succinate synthesis and cumulatively enhancing the expression of efflux transporters, which improved patchoulol production to 338.6 mg/L. When tested in a bioreactor, the patchoulol titer and productivity were further improved to 970.1 mg/L and 199 mg/L/d, respectively, and were among the highest levels reported using mineral salt medium.


Asunto(s)
Escherichia coli , Sesquiterpenos , Escherichia coli/genética , Fermentación , Ingeniería Metabólica , Ácido Succínico
8.
Int J Mol Sci ; 22(11)2021 Jun 04.
Artículo en Inglés | MEDLINE | ID: mdl-34199768

RESUMEN

Single mutations can confer resistance to antibiotics. Identifying such mutations can help to develop and improve drugs. Here, we systematically screen for candidate quinolone resistance-conferring mutations. We sequenced highly diverse wastewater E. coli and performed a genome-wide association study (GWAS) to determine associations between over 200,000 mutations and quinolone resistance phenotypes. We uncovered 13 statistically significant mutations including 1 located at the active site of the biofilm dispersal gene bdcA and 6 silent mutations in the aminoacyl-tRNA synthetase valS. The study also recovered the known mutations in the topoisomerases gyrase (gyrA) and topoisomerase IV (parC). In summary, we demonstrate that GWAS effectively and comprehensively identifies resistance mutations without a priori knowledge of targets and mode of action. The results suggest that mutations in the bdcA and valS genes, which are involved in biofilm dispersal and translation, may lead to novel resistance mechanisms.


Asunto(s)
Farmacorresistencia Bacteriana/genética , Proteínas de Escherichia coli/genética , Escherichia coli/genética , Mutación/genética , Quinolonas/farmacología , Aguas Residuales/microbiología , Antibacterianos/farmacología , Escherichia coli/efectos de los fármacos , Escherichia coli/aislamiento & purificación , Sitios Genéticos , Estudio de Asociación del Genoma Completo , Desequilibrio de Ligamiento/genética , Modelos Moleculares , Fenotipo , Filogenia
9.
Int J Mol Sci ; 22(12)2021 Jun 14.
Artículo en Inglés | MEDLINE | ID: mdl-34198485

RESUMEN

Brain microvascular endothelial cells (BMECs) constitute the structural and functional basis for the blood-brain barrier (BBB) and play essential roles in bacterial meningitis. Although the BBB integrity regulation has been under extensive investigation, there is little knowledge regarding the roles of long non-coding RNAs (lncRNAs) in this event. The present study aimed to investigate the roles of one potential lncRNA, lncRSPH9-4, in meningitic E. coli infection of BMECs. LncRSPH9-4 was cytoplasm located and significantly up-regulated in meningitic E. coli-infected hBMECs. Electrical cell-substrate impedance sensing (ECIS) measurement and Western blot assay demonstrated lncRSPH9-4 overexpression in hBMECs mediated the BBB integrity disruption. By RNA-sequencing analysis, 639 mRNAs and 299 miRNAs were significantly differentiated in response to lncRSPH9-4 overexpression. We further found lncRSPH9-4 regulated the permeability in hBMECs by competitively sponging miR-17-5p, thereby increasing MMP3 expression, which targeted the intercellular tight junctions. Here we reported the infection-induced lncRSPH9-4 aggravated disruption of the tight junctions in hBMECs, probably through the miR-17-5p/MMP3 axis. This finding provides new insights into the function of lncRNAs in BBB integrity during meningitic E. coli infection and provides the novel nucleic acid targets for future treatment of bacterial meningitis.


Asunto(s)
Barrera Hematoencefálica/metabolismo , Barrera Hematoencefálica/patología , Escherichia coli/fisiología , Metaloproteinasa 3 de la Matriz/metabolismo , Meningitis Bacterianas/genética , Meningitis Bacterianas/microbiología , MicroARNs/metabolismo , ARN Largo no Codificante/metabolismo , Secuencia de Bases , Citoplasma/metabolismo , Células Endoteliales/metabolismo , Células Endoteliales/microbiología , Redes Reguladoras de Genes , Humanos , MicroARNs/genética , Microvasos/patología , Modelos Biológicos , Permeabilidad , ARN Largo no Codificante/genética , ARN Mensajero/genética , ARN Mensajero/metabolismo , Transducción de Señal , Uniones Estrechas/metabolismo , Transcripción Genética , Regulación hacia Arriba/genética
10.
Environ Monit Assess ; 193(8): 471, 2021 Jul 05.
Artículo en Inglés | MEDLINE | ID: mdl-34226964

RESUMEN

Shellfish-growing areas in marine environments are affected by pollutants that mainly originate from land, including streams, domestic wastewater, and the effluents of wastewater treatment plants (WWTPs), which may function as reservoirs of antibiotic-resistant bacteria (ARB) and antibiotic-resistance genes (ARGs). The objective of this study was to identify the occurrence and distribution of antibiotic resistance at five oyster sampling sites and 11 major inland pollution sources in the drainage basin of Kamak Bay, Republic of Korea. Culture-based methods were used to estimate the diversity and abundance of antibiotic-resistant Escherichia coli strains isolated from oysters and major inland pollution sources. The percentages of ARB and multiple antibiotic resistance index values were significantly high in discharge water from small fishing villages without WWTPs. However, the percentages of antibiotic-resistant E. coli isolates from oysters were low, as there was no impact from major inland pollutants. Fourteen ARGs were also quantified from oysters and major inland pollution sources. Although most ARGs except for quinolones were widely distributed in domestic wastewater discharge and effluent from WWTPs, macrolide resistance genes (ermB and msrA) were detected mainly from oysters in Kamak Bay. This study will aid in tracking the sources of antibiotic contamination in shellfish to determine the correlation between shellfish and inland pollution sources.


Asunto(s)
Antibacterianos , Farmacorresistencia Bacteriana , Escherichia coli/efectos de los fármacos , Mariscos/microbiología , Bahías , Monitoreo del Ambiente , Escherichia coli/genética , Genes Bacterianos , Macrólidos , República de Corea , Aguas Residuales/análisis
11.
Sheng Wu Gong Cheng Xue Bao ; 37(6): 2105-2115, 2021 Jun 25.
Artículo en Chino | MEDLINE | ID: mdl-34227297

RESUMEN

Triterpenoids are a class of natural products of great commercial value that are widely used in pharmaceutical, health care and cosmetic industries. The biosynthesis of triterpenoids relies on the efficient synthesis of squalene epoxide, which is synthesized from the NADPH dependent oxidation of squalene catalyzed by squalene epoxidase. We screened squalene epoxidases derived from different species, and found the truncated squalene epoxidase from Rattus norvegicus (RnSETC) showed the highest activity in engineered Escherichia coli. Further examination of the effect of endogenous cytochrome P450 reductase like (CPRL) proteins showed that overexpression of NADH: quinone oxidoreductase (WrbA) under Lac promoter in a medium-copy number plasmid increased the production of squalene epoxide by nearly 2.5 folds. These results demonstrated that the constructed pathway led to the production of squalene epoxide, an important precursor for the biosynthesis of triterpenoids.


Asunto(s)
Escualeno-Monooxigenasa , Escualeno , Animales , Escherichia coli/genética , NADPH-Ferrihemoproteína Reductasa , Ingeniería de Proteínas , Ratas , Proteínas Represoras , Escualeno-Monooxigenasa/genética
12.
J Agric Food Chem ; 69(28): 7932-7937, 2021 Jul 21.
Artículo en Inglés | MEDLINE | ID: mdl-34232654

RESUMEN

l-Methionine is an essential bioactive amino acid with high commercial value for diverse applications. Sustained attentions have been paid to efficient and economical preparation of l-methionine. In this work, a novel method for l-methionine production was established using O-acetyl-homoserine (OAH) and 3-methylthiopropionaldehyde (MMP) as substrates by catalysis of the yeast OAH sulfhydrylase MET17. The OAH sulfhydrylase gene Met17 was cloned from Saccharomyces cerevisiae S288c and overexpressed in Escherichia coli BL21. A 49 kDa MET17 was detected in the supernatant of the recombinant E. coli strain BL21-Met17 lysate with IPTG induction, which exhibited the biological activity of l-methionine biosynthesis from OAH and MMP. The recombinant MET17 was then purified from E. coli BL21-Met17 and used for in vitro biosynthesis of l-methionine. The maximal conversion rate (86%) of OAH to l-methionine catalyzed by purified MET17 was achieved by optimization of the molar ratio of OAH to MMP. The method proposed in this study provides a possible novel route for the industrial production of l-methionine.


Asunto(s)
Metionina , Saccharomyces cerevisiae , Liasas de Carbono-Oxígeno , Catálisis , Escherichia coli/genética , Cinética , Saccharomyces cerevisiae/genética
13.
J Agric Food Chem ; 69(28): 7922-7931, 2021 Jul 21.
Artículo en Inglés | MEDLINE | ID: mdl-34236173

RESUMEN

Stilbenes and flavonoids are two major health-promoting phenylpropanoid groups in grapes. Attempts to promote the accumulation of one group usually resulted in a decrease in the other. This study presents a unique strategy for simultaneously increasing metabolites in both groups in V. vinifera cv. Gamay Red grape cell culture, by overexpression of flavonol synthase (FLS) and increasing Phe availability. Increased Phe availability was achieved by transforming the cell culture with a second gene, the feedback-insensitive E. coli DAHP synthase (AroG*), and feeding them with Phe. A combined metabolomic and transcriptomic analysis reveals that the increase in both phenylpropanoid groups is accompanied by an induction of many of the flavonoid biosynthetic genes and no change in the expression levels of stilbene synthase. Furthermore, FLS overexpression with increased Phe availability resulted in higher anthocyanin levels, mainly those derived from delphinidin, due to the induction of F3'5'H. These insights may contribute to the development of grape berries with increased health benefits.


Asunto(s)
Estilbenos , Vitis , Antocianinas , Técnicas de Cultivo de Célula , Escherichia coli/genética , Flavonoides , Frutas/genética , Regulación de la Expresión Génica de las Plantas , Vitis/genética
14.
Environ Monit Assess ; 193(8): 497, 2021 Jul 20.
Artículo en Inglés | MEDLINE | ID: mdl-34286386

RESUMEN

In the present work, leaf extract of Boswellia sacra was used as reductant for synthesis of silver nanoparticles (AgNPs). The variables such as volume of Boswellia sacra leaf extract (1%), volume of silver nitrate (1 mM), and temperature were optimized by response surface methodology via Box-Behnken design for the synthesis of AgNPs. Design-Expert software generated the optimum conditions for the highest yield of silver nanoparticles as 8 mL of 1 mM AgNO3, 8 mL of 1% Boswellia sacra leaf extract, and temperature = 55 °C. The formed AgNPs were isolated and purified by centrifugation process using ethanol/ distilled water. AgNPs were characterized using FTIR, SEM, TEM, EDX, and XRD. AgNPs showed surface plasmon resonance absorption band at 422 nm. XRD pattern indicated the crystalline nature of the particles (diameter 11.17 to 37.50 nm) with face-centered cubic structure. SEM and TEM images highlighted the formation of spherical AgNPs. The energy dispersive spectroscopic spectrum confirmed the presence of elemental silver. The microbial activity of AgNPs was evaluated against bacteria and fungi. Synthesized AgNPs were very effective against Gram-positive E. coli bacterial strains and fungal strains (Penicillium chrysogenum).


Asunto(s)
Boswellia , Nanopartículas del Metal , Antibacterianos , Monitoreo del Ambiente , Escherichia coli , Pruebas de Sensibilidad Microbiana , Extractos Vegetales , Plata
15.
Molecules ; 26(11)2021 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-34206015

RESUMEN

New polymer-bioactive compound systems were obtained by immobilization of triazole derivatives onto grafted copolymers and grafted copolymers carrying betaine units based on gellan and N-vinylimidazole. For preparation of bioactive compound, two new types of heterocyclic thio-derivatives with different substituents were combined in a single molecule to increase the selectivity of the biological action. The 5-aryl-amino-1,3,4 thiadiazole and 5-mercapto-1,2,4-triazole derivatives, each containing 2-mercapto-benzoxazole nucleus, were prepared by an intramolecular cyclization of thiosemicarbazides-1,4 disubstituted in acidic and basic medium. The structures of the new bioactive compounds were confirmed by elemental and spectral analysis (FT-IR and 1H-NMR). The antimicrobial activity of 1,3,4 thiadiazoles and 1,2,4 triazoles was tested on gram-positive and gram-negative bacteria. The triazole compound was chosen to be immobilized onto polymeric particles by adsorption. The Langmuir, Freundlich, and Dubinin-Radushkevich adsorption isotherm were used to describe the adsorption equilibrium. Also, the pseudo-first and pseudo-second models were used to elucidate the adsorption mechanism of triazole onto grafted copolymer based on N-vinylimidazole and gellan (PG copolymer) and grafted copolymers carrying betaine units (PGB1 copolymer). In vitro release studies have shown that the release mechanism of triazole from PG and PGB1 copolymers is characteristic of an anomalous transport mechanism.


Asunto(s)
Antibacterianos/síntesis química , Betaína/química , Polisacáridos Bacterianos/química , Triazoles/síntesis química , Antibacterianos/química , Antibacterianos/farmacología , Bacillus cereus/efectos de los fármacos , Bacillus subtilis/efectos de los fármacos , Ciclización , Escherichia coli/efectos de los fármacos , Pruebas de Sensibilidad Microbiana , Salmonella enteritidis/efectos de los fármacos , Staphylococcus aureus/efectos de los fármacos , Triazoles/química , Triazoles/farmacología
16.
J Nanosci Nanotechnol ; 21(12): 5945-5959, 2021 12 01.
Artículo en Inglés | MEDLINE | ID: mdl-34229790

RESUMEN

Zinc oxide nanoparticles were synthesized using different surfactants such as SDS, CTAB, Triton X-100, PVP K-30 and ethylene glycol. ZnO NPs were tested for antibacterial activity before and after calcination against different micro-organisms like E. coli and P. aeruginosa (Gram negative) as well as S. aureus and B. subtilis (Gram positive). Antibacterial activity was observed in SDScapped ZnO NPs only against B. subtilis. Antibacterial activity of ZnO-capped SDS was tested in a concentration range 0.625-10 mg/mL. Increased antibacterial activity was observed before calcination as compared to after calcination. Minimum concentration at which uncalcinated as well as calcinated SDS-capped ZnO NPs show antibacterial activity is 2.5 mg/mL and 5 mg/mL respectively. Non-antibacterial nature of ZnO NPs highlights its further use in drug delivery due to its inert nature, enhanced efficacy in association with therapeutic drugs as well as easy disposal.


Asunto(s)
Nanopartículas , Óxido de Zinc , Antibacterianos/farmacología , Escherichia coli , Pruebas de Sensibilidad Microbiana , Staphylococcus aureus , Tensoactivos/farmacología , Óxido de Zinc/farmacología
17.
Soft Matter ; 17(28): 6688-6696, 2021 Jul 21.
Artículo en Inglés | MEDLINE | ID: mdl-34240085

RESUMEN

Herein, we report a method of fabricating strong and thermosensitive double network (T-DN) poly(N-isopropyl acrylamide) (PNIPAM)-based hydrogels, i.e. rigid and brittle poly(2-acrylamido-2-methylpropanesulfonic acid sodium salt) (PNaAMPS) as the first and soft and ductile poly(N-isopropyl acrylamide-co-acrylamide) (P(NIPAM-co-AAm)) as the second interpenetrating each other. In particular, NIPAM was deliberately integrated into the double network as an adjustor of elastic modulus and hydrophilicity, besides thermosensitivity. Such double network construction strategy resulted in PNaAMPS/P(NIPAM-co-AAm) T-DN hydrogels of excellent mechanical properties (0.83-1.37 MPa) and desirable temperature-dependent swellabilities. Besides, T-DN hydrogels with various NIPAM contents exhibited good biocompatibility with high cell survival rates around normal body temperatures. Furthermore, crystal violet (CV) could be readily loaded to impart antibacterial functionality to the T-DN hydrogels against E. coli. The double network construction strategy could be adapted to fabricating high-strength antibacterial hydrogels for a broad range of biomedical applications.


Asunto(s)
Escherichia coli , Hidrogeles , Antibacterianos , Módulo de Elasticidad , Resistencia a la Tracción
18.
Int J Mol Sci ; 22(11)2021 Jun 07.
Artículo en Inglés | MEDLINE | ID: mdl-34200244

RESUMEN

Ribosome biogenesis is a highly coordinated and complex process that requires numerous assembly factors that ensure prompt and flawless maturation of ribosomal subunits. Despite the increasing amount of data collected, the exact role of most assembly factors and mechanistic details of their operation remain unclear, mainly due to the shortage of high-resolution structural information. Here, using cryo-electron microscopy, we characterized 30S ribosomal particles isolated from an Escherichia coli strain with a deleted gene for the RbfA factor. The cryo-EM maps for pre-30S subunits were divided into six classes corresponding to consecutive assembly intermediates: from the particles with a completely unresolved head domain and unfolded central pseudoknot to almost mature 30S subunits with well-resolved body, platform, and head domains and partially distorted helix 44. The structures of two predominant 30S intermediates belonging to most populated classes obtained at 2.7 Å resolutions indicate that RbfA acts at two distinctive 30S assembly stages: early formation of the central pseudoknot including folding of the head, and positioning of helix 44 in the decoding center at a later stage. Additionally, it was shown that the formation of the central pseudoknot may promote stabilization of the head domain, likely through the RbfA-dependent maturation of the neck helix 28. An update to the model of factor-dependent 30S maturation is proposed, suggesting that RfbA is involved in most of the subunit assembly process.


Asunto(s)
Proteínas de Escherichia coli/metabolismo , Escherichia coli/fisiología , Proteínas Ribosómicas/metabolismo , Subunidades Ribosómicas Pequeñas Bacterianas/fisiología , Ribosomas/metabolismo , Sitios de Unión , Microscopía por Crioelectrón/métodos , Proteínas de Escherichia coli/genética , Modelos Moleculares , Unión Proteica , Proteínas Ribosómicas/genética , Subunidades Ribosómicas Pequeñas Bacterianas/ultraestructura , Ribosomas/ultraestructura
19.
Int J Mol Sci ; 22(11)2021 Jun 07.
Artículo en Inglés | MEDLINE | ID: mdl-34200430

RESUMEN

The virus-host interaction requires a complex interplay between the phage strategy of reprogramming the host machinery to produce and release progeny virions, and the host defense against infection. Using RNA sequencing, we investigated the phage-host interaction to resolve the phenomenon of improved lytic development of P1vir phage in a DksA-deficient E. coli host. Expression of the ant1 and kilA P1vir genes in the wild-type host was the highest among all and most probably leads to phage virulence. Interestingly, in a DksA-deficient host, P1vir genes encoding lysozyme and holin are downregulated, while antiholins are upregulated. Gene expression of RepA, a protein necessary for replication initiating at the phage oriR region, is increased in the dksA mutant; this is also true for phage genes responsible for viral morphogenesis and architecture. Still, it seems that P1vir is taking control of the bacterial protein, sugar, and lipid metabolism in both, the wild type and dksA- hosts. Generally, bacterial hosts are reacting by activating their SOS response or upregulating the heat shock proteins. However, only DksA-deficient cells upregulate their sulfur metabolism and downregulate proteolysis upon P1vir infection. We conclude that P1vir development is enhanced in the dksA mutant due to several improvements, including replication and virion assembly, as well as a less efficient lysis.


Asunto(s)
Proteínas Bacterianas/metabolismo , Bacteriófagos/patogenicidad , Proteínas de Escherichia coli/metabolismo , Escherichia coli/genética , Interacciones Microbiota-Huesped/genética , Transcriptoma , Proteínas Bacterianas/genética , Escherichia coli/crecimiento & desarrollo , Escherichia coli/virología , Proteínas de Escherichia coli/genética , Regulación Bacteriana de la Expresión Génica , Virulencia
20.
Int J Mol Sci ; 22(12)2021 Jun 10.
Artículo en Inglés | MEDLINE | ID: mdl-34200743

RESUMEN

Mastitis is a common disease in dairy cows that is mostly caused by E. coli, and it brings massive losses to the dairy industry. N6-Methyladenosine (m6A), a methylation at the N6 position of RNA adenine, is a type of modification strongly associated with many diseases. However, the role of m6A in mastitis has not been investigated. In this study, we used MeRIP-seq to sequence the RNA of bovine mammary epithelial cells treated with inactivated E. coli for 24 h. In this in vitro infection model, there were 16,691 m6A peaks within 7066 mRNA transcripts in the Con group and 10,029 peaks within 4891 transcripts in the E. coli group. Compared with the Con group, 474 mRNAs were hypermethylated and 2101 mRNAs were hypomethylated in the E. coli group. Biological function analyses revealed differential m6A-modified genes mainly enriched in the MAPK, NF-κB, and TGF-ß signaling pathways. In order to explore the relationship between m6A and mRNA expression, combined MeRIP-seq and mRNA-seq analyses revealed 212 genes with concomitant changes in the mRNA expression and m6A modification. This study is the first to present a map of RNA m6A modification in mastitis treated with E. coli, providing a basis for future research.


Asunto(s)
Adenosina/análogos & derivados , Metilación de ADN , Células Epiteliales/metabolismo , Infecciones por Escherichia coli/veterinaria , Regulación de la Expresión Génica , Glándulas Mamarias Animales/metabolismo , Mastitis Bovina/genética , Adenosina/química , Animales , Bovinos , Células Epiteliales/inmunología , Células Epiteliales/microbiología , Escherichia coli/aislamiento & purificación , Infecciones por Escherichia coli/genética , Infecciones por Escherichia coli/inmunología , Femenino , Perfilación de la Expresión Génica , Glándulas Mamarias Animales/inmunología , Glándulas Mamarias Animales/microbiología , Mastitis Bovina/inmunología , Mastitis Bovina/microbiología
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