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1.
Khirurgiia (Mosk) ; (5): 102-108, 2020.
Artículo en Ruso | MEDLINE | ID: mdl-32500699

RESUMEN

Hemorrhoidal disease is the most common proctologic disease and the search for new treatment methods, as well as an in-depth understanding of the mechanisms underlying effects of well-known agents on disease pathogenesis still remain relevant. There have been long recognized the effects of the E.coli bacterial culture suspension (BCS) as a therapeutic means eliciting decreased exudation during inflammation, wound healing, tissue regeneration, and stimulated immunity. Here, based on recent findings related to innate and adaptive immune cells, we set out to present mechanisms accounting for some effects coupled to commensal bacteria, particularly inactivated E.coli BCS, which are important for understanding pathogenesis-related action of drug Posterisan and Posterisan forte, and outline their broad application in therapy of hemorrhoids. Based on the analysis, it was concluded that such effects are mediated via multi-pronged and complementary interactions between diverse human receptors expressed in the anorectal region cells and microbial components: NOD ligands, metabolites, enzymes, heat shock proteins and nucleic acids, which lead to production of pro-inflammatory cytokines by anodermal colonocytes, innate and adaptive immune cells, neurons in the submucosal plexus covered by transitional zone epithelium, and hemorrhoid plexus endothelium. Based on current concepts, it may be plausible that E.coli BCS-derived biologically active components contained in drug Posterisan are capable of exerting both positive local and systemic effects, which extend our understanding and substantiate its use in hemorrhoidal disease. The effectiveness of using Posterisan and Posterisan forte is corroborated by their indications in real-life clinical practice, both as a conservative therapy as well as after surgical interventions.


Asunto(s)
Escherichia coli , Hemorroides/terapia , Canal Anal/microbiología , Escherichia coli/aislamiento & purificación , Hemorroides/inmunología , Hemorroides/microbiología , Humanos , Pomadas/administración & dosificación , Soluciones/administración & dosificación
2.
Water Sci Technol ; 81(6): 1170-1179, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-32597404

RESUMEN

Four bioretention simulation columns were used to study the removal effects and influencing factors of Escherichia coli (E. coli) in stormwater. The mechanism of E. coli removal in the bioretention system was also analyzed. The results show that the removal effects of the four new composite filters are better than that of the conventional filter. The specific surface area and porosity of the filter may be the key factors affecting the removal effect; the increase of the filter depth is beneficial to the removal of E. coli; the area is conducive to the removal of E. coli. Excessive depth of the submerged zone will reduce the E. coli removal effect; drying will reduce the E. coli removal effect, but it can be restored by rewetting.


Asunto(s)
Escherichia coli , Purificación del Agua , Lluvia
3.
Medicine (Baltimore) ; 99(24): e20477, 2020 Jun 12.
Artículo en Inglés | MEDLINE | ID: mdl-32541470

RESUMEN

This case series investigated the efficacy and optimal dose of Escherichia coli-derived bone morphogenetic protein-2 (E.BMP-2) as a bone graft substitute for additional posterolateral spinal fusion, accompanying interbody fusion procedures, for treating lumbar degenerative spinal stenosis. This study focused on the optimal dose for each segment and the efficacy of E.BMP-2 as a substitute for autogenous iliac bone graft.Ten patients were enrolled from January 2015 to December 2015, and underwent an additional posterolateral fusion procedure, with 2.5 mg of E.BMP-2 followed by decompression, transpedicular fixation, and interbody fusion. The mean follow-up period was 13.9 months, and regular radiological examinations were performed in every case. Clinical outcomes were measured with a visual analog scale for back pain (VAS-BP), and leg pain (VAS-LP) and the Korean Oswestry Disability Index (K-ODI). All parameters were assessed preoperatively and postoperatively at 12 months.All 18 segments treated with E.BMP-2 completely fused in 6 months as observed on both simple radiography and computed tomography. The mean fusion period was 4.5 months on simple radiography. At 12 months follow-up, VAS-BP, VAS-LP, and K-ODI scores (1.9 ±â€Š1.5, 1.9 ±â€Š1.9, 11.0 ±â€Š6.6, respectively) had improved significantly compared to preoperative scores (5.5 ±â€Š1.9, 6.5 ±â€Š1.9, and 49.9 ±â€Š11.5, respectively, P < .05). There were no postoperative wound infections, neurological symptoms, or complications associated with the use of E.BMP-2 during the follow-up period.E.BMP-2 could be used to enhance the outcomes in posterolateral spinal fusion following interbody fusion surgery. In the present study, 2.5 mg of the E.BMP-2 per segment was sufficient to obtain bony union in posterolateral fusion surgery. Further large-scale trials with long-term follow-up are necessary to evaluate the various complications related to the use of E.BMP-2.


Asunto(s)
Proteína Morfogenética Ósea 2/uso terapéutico , Vértebras Lumbares/cirugía , Fusión Vertebral , Estenosis Espinal/cirugía , Anciano , Anciano de 80 o más Años , Escherichia coli , Femenino , Humanos , Masculino , Persona de Mediana Edad , Proyectos Piloto , Proteínas Recombinantes/uso terapéutico , Estudios Retrospectivos , Estenosis Espinal/tratamiento farmacológico
4.
Sheng Wu Gong Cheng Xue Bao ; 36(5): 932-941, 2020 May 25.
Artículo en Chino | MEDLINE | ID: mdl-32567276

RESUMEN

Endo-ß-N-acetylglucosaminidase is used widely in the glycobiology studies and industries. In this study, a new endo-ß-N-acetylglucosaminidase, designated as Endo SA, was cloned from Streptomyces alfalfae ACCC 40021 and expressed in Escherichia coli BL21 (DE3). The purified recombinant Endo SA exhibited the maximum activity at 35 ºC and pH 6.0, good thermo/pH stability and high specific activity (1.0×106 U/mg). It displayed deglycosylation activity towards different protein substrates. These good properties make EndoSA a potential tool enzyme and industrial biocatalyst.


Asunto(s)
Manosil-Glicoproteína Endo-beta-N-Acetilglucosaminidasa , Streptomyces , Clonación Molecular , Estabilidad de Enzimas , Escherichia coli/genética , Expresión Génica , Manosil-Glicoproteína Endo-beta-N-Acetilglucosaminidasa/genética , Manosil-Glicoproteína Endo-beta-N-Acetilglucosaminidasa/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Streptomyces/enzimología , Streptomyces/genética
5.
Sheng Wu Gong Cheng Xue Bao ; 36(5): 992-1001, 2020 May 25.
Artículo en Chino | MEDLINE | ID: mdl-32567282

RESUMEN

In this study, Escherichia coli BL21 (DE3) was used as the host to construct 2 recombinant E. coli strains that co-expressed leucine dehydrogenase (LDH, Bacillus cereus)/formate dehydrogenase (FDH, Ancylobacter aquaticus), or leucine dehydrogenase (LDH, Bacillus cereus)/alcohol dehydrogenase (ADH, Rhodococcus), respectively. L-2-aminobutyric acid was then synthesized by L-threonine deaminase (L-TD) with LDH-FDH or LDH-ADH by coupling with two different NADH regeneration systems. LDH-FDH process and LDH-ADH process were optimized and compared with each other. The optimum reaction pH of LDH-FDH process was 7.5, and the optimum reaction temperature was 35 °C. After 28 h, the concentration of L-2-aminobutyric acid was 161.8 g/L with a yield of 97%, when adding L-threonine in batches for controlling 2-ketobutyric acid concentration less than 15 g/L and using 50 g/L ammonium formate, 0.3 g/L NAD+, 10% LDH-FDH crude enzyme solution (V/V) and 7 500 U/L L-TD. The optimum reaction pH of LDH-ADH process was 8.0, and the optimum reaction temperature was 35 °C. After 24 h, the concentration of L-2-aminobutyric acid was 119.6 g/L with a yield of 98%, when adding L-threonine and isopropanol (1.2 times of L-threonine) in batches for controlling 2-ketobutyric acid concentration less than 15 g/L, removing acetone in time and using 0.3 g/L NAD⁺, 10% LDH-ADH crude enzyme solution (V/V) and 7 500 U/L L-TD. The process and results used in this paper provide a reference for the industrialization of L-2-aminobutyric acid.


Asunto(s)
Aminobutiratos , Leucina-Deshidrogenasa , NAD , Aminobutiratos/metabolismo , Escherichia coli/genética , Formiato Deshidrogenasas/metabolismo , Leucina-Deshidrogenasa/metabolismo , NAD/metabolismo
6.
Sheng Wu Gong Cheng Xue Bao ; 36(5): 1002-1011, 2020 May 25.
Artículo en Chino | MEDLINE | ID: mdl-32567283

RESUMEN

Uridine-cytidine kinase, an important catalyst in the compensation pathway of nucleotide metabolism, can catalyze the phosphorylation reaction of cytidine to 5'-cytidine monophosphate (CMP), but the reaction needs NTP as the phosphate donor. To increase the production efficiency of CMP, uridine-cytidine kinase gene from Thermus thermophilus HB8 and polyphosphate kinase gene from Rhodobacter sphaeroides were cloned and expressed in Escherichia coli BL21(DE3). Uridine-cytidine kinase was used for the generation of CMP from cytidine and ATP, and polyphosphate kinase was used for the regeneration of ATP. Then, the D403 metal chelate resin was used to adsorb Ni²âº to form an immobilized carrier, and the immobilized carrier was specifically combined with the recombinant enzymes to form the immobilized enzymes. Finally, single-factor optimization experiment was carried out to determine the reaction conditions of the immobilized enzyme. At 30 °C and pH 8.0, 60 mmol/L cytidine and 0.5 mmol/L ATP were used as substrates to achieve 5 batches of high-efficiency continuous catalytic reaction, and the average molar yield of CMP reached 91.2%. The above method has the advantages of low reaction cost, high product yield and high enzyme utilization rate, and has good applied value for industrial production.


Asunto(s)
Citidina Monofosfato , Microbiología Industrial , Fosfotransferasas (Aceptor del Grupo Fosfato) , Uridina Quinasa , Citidina Monofosfato/metabolismo , Escherichia coli/genética , Microbiología Industrial/métodos , Fosfotransferasas (Aceptor del Grupo Fosfato)/metabolismo
7.
Sci Total Environ ; 729: 139028, 2020 Aug 10.
Artículo en Inglés | MEDLINE | ID: mdl-32498177

RESUMEN

The goal of the present study was to select a Gram-positive (Gram+) and Gram-negative (Gram-) strain to measure antimicrobial activity in environmental samples, allowing high-throughput environmental screening. The sensitivity of eight pre-selected bacterial strains were tested to a training set of ten antibiotics, i.e. three Gram+ Bacillus subtilis strains with different read-outs, and five Gram- strains. The latter group consisted of a bioluminescent Allivibrio fischeri strain and four Escherichia coli strains, i.e. a wild type (WT) and three strains with a modified cell envelope to increase their sensitivity. The WT B. subtilis and an E. coli strain newly developed in this study, were most sensitive to the training set. This E. coli strain carries an open variant of an outer membrane protein combined with an inactivated multidrug efflux transport system. The assay conditions of these two strains were optimized and validated by exposure to a validation set of thirteen antibiotics with clinical and environmental relevance. The assay sensitivity ranged from the ng/mL to µg/mL range. The applicability of the assays for toxicological characterization of aquatic environmental samples was demonstrated for hospital effluent extract. A future application includes effect-directed analysis to identify yet unknown antibiotic contaminants or their transformation products.


Asunto(s)
Bioensayo , Antibacterianos , Bacillus subtilis , Escherichia coli , Ensayos Analíticos de Alto Rendimiento , Pruebas de Sensibilidad Microbiana
8.
J Environ Manage ; 268: 110693, 2020 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-32510435

RESUMEN

The demand for systems that efficiently and sustainably recover value-added compounds and materials from waste streams is a major challenge. The use of wastewater as a source for recovery of carbon and nutrients is an attractive and sustainable alternative. In this study, anaerobically treated black water was treated in photobioreactors (PBRs) inoculated with Chlorella sorokiniana, and the process was investigated in terms of phosphorus and nitrogen removal, biomass growth, and the removal of pathogens. The consumption of bicarbonate (alkalinity) and acetate (volatile fatty acids) as carbon sources by microalgae was investigated. The average nutrient removal achieved was 66% for N and 74% for P. A high consumption of alkalinity (83%) and volatile organic acids (76%) was observed, which suggests that these compounds were used as a source of carbon. The biomass production was 73 mg L-1 day-1, with a mean biomass of 0.7 g L-1 at the end of the batch treatment. At the end of the experiments, a log removal/inactivation of 0.51 log for total coliforms and 2.73 log for Escherichia coli (E. coli) was observed. The configuration used, a flat-panel PBR operated in batch mode without CO2 supplementation, is a cost-effective and environmentally sustainable method for recovering of nutrients and production of algal biomass.


Asunto(s)
Chlorella , Microalgas , Biomasa , Escherichia coli , Nitrógeno , Nutrientes , Fósforo , Fotobiorreactores , Aguas Residuales , Agua
9.
Cell Rep ; 31(11): 107774, 2020 06 16.
Artículo en Inglés | MEDLINE | ID: mdl-32531208

RESUMEN

The ongoing global pandemic of coronavirus disease 2019 (COVID-19) has caused a huge number of human deaths. Currently, there are no specific drugs or vaccines available for this virus (SARS-CoV-2). The viral polymerase is a promising antiviral target. Here, we describe the near-atomic-resolution structure of the SARS-CoV-2 polymerase complex consisting of the nsp12 catalytic subunit and nsp7-nsp8 cofactors. This structure highly resembles the counterpart of SARS-CoV with conserved motifs for all viral RNA-dependent RNA polymerases and suggests a mechanism of activation by cofactors. Biochemical studies reveal reduced activity of the core polymerase complex and lower thermostability of individual subunits of SARS-CoV-2 compared with SARS-CoV. These findings provide important insights into RNA synthesis by coronavirus polymerase and indicate adaptation of SARS-CoV-2 toward humans with a relatively lower body temperature than the natural bat hosts.


Asunto(s)
Betacoronavirus/enzimología , Microscopía por Crioelectrón , ARN Replicasa/química , Proteínas no Estructurales Virales/química , Sustitución de Aminoácidos , Escherichia coli/genética , Evolución Molecular , Modelos Moleculares , Complejos Multiproteicos/química , ARN Replicasa/metabolismo , Virus del SRAS/enzimología , Proteínas no Estructurales Virales/metabolismo
10.
Biol Res ; 53(1): 26, 2020 Jun 08.
Artículo en Inglés | MEDLINE | ID: mdl-32513271

RESUMEN

BACKGROUND: There is an emerging field to put into practice new strategies for developing molecules with antimicrobial properties. In this line, several metals and metalloids are currently being used for these purposes, although their cellular effect(s) or target(s) in a particular organism are still unknown. Here we aimed to investigate and analyze Au3+ toxicity through a combination of biochemical and molecular approaches. RESULTS: We found that Au3+ triggers a major oxidative unbalance in Escherichia coli, characterized by decreased intracellular thiol levels, increased superoxide concentration, as well as by an augmented production of the antioxidant enzymes superoxide dismutase and catalase. Because ROS production is, in some cases, associated with metal reduction and the concomitant generation of gold-containing nanostructures (AuNS), this possibility was evaluated in vivo and in vitro. CONCLUSIONS: Au3+ is toxic for E. coli because it triggers an unbalance of the bacterium's oxidative status. This was demonstrated by using oxidative stress dyes and antioxidant chemicals as well as gene reporters, RSH concentrations and AuNS generation.


Asunto(s)
Escherichia coli/efectos de los fármacos , Oro/toxicidad , Nanopartículas del Metal/toxicidad , Oxidación-Reducción/efectos de los fármacos , Estrés Oxidativo/efectos de los fármacos
11.
J Environ Manage ; 267: 110567, 2020 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-32364129

RESUMEN

Land spreading of dairy soiled water (DSW) may result in pollution of ground and surface waters. Treatment of DSW through sludge-supernatant separation using chemical coagulants is a potential option to reduce the negative environmental impacts of DSW. The aims of this study were to (1) assess the effectiveness of three chemical coagulants - poly-aluminium chloride (PACl), ferric chloride (FeCl3) and alum - in improving effluent quality, and (2) assess the properties of the sludge that is generated as by-product from the process for its suitability for land application. Taking into consideration optimum doses to minimize pollutants (turbidity, chemical oxygen demand (COD), total phosphorus (TP), total nitrogen (TN), and E. coli), optimum mixing times and cost, FeCl3 was the best performing coagulant. Generated sludges had higher nutrient content and fewer E. coli than raw DSW, and did not display any evidence of phytotoxicity to the growth of Lolium perenne L. using germination tests. The study discussed the results in a sustainable farm management context, and suggested that the effluent (supernatant) from the treatments may be recycled to wash farm yards, saving water. In parallel, the sludge portion can be applied to amend soil properties with no adverse impacts on the grass growth, providing an agronomic value as an organic fertilizer, and reducing the risk of nutrient losses. This management approach could minimize the overall net cost compared to land application of raw DSW.


Asunto(s)
Cloruro de Aluminio , Suelo , Compuestos de Alumbre , Cloruros , Escherichia coli , Compuestos Férricos , Eliminación de Residuos Líquidos
12.
J Environ Manage ; 265: 110529, 2020 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-32421557

RESUMEN

Wastewater flows from metropolitan areas, especially those with healthcare inputs, can serve as transport reservoirs for the dissemination of clinically-relevant antimicrobial resistant bacteria (ARB) such as carbapenem- (CR) and colistin-resistant (CoR) strains. Pulsed electric field (PEF) is an emerging wastewater management tool for reducing bacterial loads without generating environmentally harmful byproducts, but it's ability to reduce ARB and their genetic determinants is not well reported. We collected 86, 10-L raw wastewater influent samples from a large metropolitan wastewater treatment plant in Columbus, Ohio and subjected them to low (34 kV cm-1 for 67 µsec) and high (36 kV cm-1 for 89 µsec) PEF treatment. We quantified the PEF effectiveness by measuring concentrations of total coliform bacteria, CR and CoR bacteria, and the epidemic carbapenemase gene, blaKPC, before and after PEF treatment. Utilizing marginal linear regression models with generalized estimating equations, we observed that low and high PEF treatment resulted in a 1.94 (95% CI 2.06-1.81; P < 0.001) and 2.32 (95% CI 2.46-2.18; P < 0.001) log reduction of total coliform bacteria concentrations, respectively. Low and high PEF treatment produced similar log reductions between CR E. coli (2.01 (95% CI 2.15-1.86; P < 0.001); 2.14 (95% CI: 5.30-4.61; P < 0.001)) and CR Enterobacteriaceae concentrations (1.55 (95% CI 1.70-1.41; P < 0.001); 1.86 (95% CI 2.05-1.68; P < 0.001)), and resulted in a 1.15 log (95% CI 1.38-0.93, P < 0.001) and 1.28 log (95% CI 1.54-1.03, P < 0.001) reduction of absolute blaKPC concentrations. Log CoR E. coli concentrations were reduced by 2.47 (95% CI 2.78-2.15; P < 0.001) and 2.52 (95% CI 2.91-2.15; P < 0.001) and CoR Enterobacteriaceae by 2.24 (95% CI 2.52-1.95; P < 0.001) and 2.50 (95% CI 2.89-2.11; P < 0.001) following low and high PEF application. PEF can be applied for wastewater management as an independent treatment method, particularly at critical control points, such as an on-site management of wastewater from hospitals or other healthcare facilities, or in series with other conventional methods to reduce total bacterial loads and concentrations of clinically-relevant ARB.


Asunto(s)
Colistina , Microbiota , Antibacterianos , Proteínas Bacterianas , Carbapenémicos , Escherichia coli , Ohio , Aguas Residuales , beta-Lactamasas
13.
Water Res ; 178: 115816, 2020 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-32353612

RESUMEN

Universalising actions aimed at water supply in rural communities and indigenous populations must focus on simple and low-cost technologies adapted to the local context. In this setting, this research studied the dynamic gravel filter (DGF) as a pre-treatment to household slow-sand filters (HSSFs), which is the first description of a household multistage filtration scale to treat drinking water. DGFs (with and without a non-woven blanket on top of the gravel layer) followed by HSSFs were tested. DGFs operated with a filtration rate of 3.21 m3 m-2.d-1 and HSSFs with 1.52 m3 m-2.d-1. Influent water contained kaolinite, humic acid and suspension of coliforms and protozoa. Physical-chemical parameters were evaluated, as well as Escherichia coli, Giardia spp. cysts and Cryptosporidium spp. oocyst reductions. Removal was low (up to 6.6%) concerning true colour, total organic carbon and absorbance (λ = 254 nm). Nevertheless, HMSFs showed turbidity decrease above 60%, E. coli reduction up to 1.78 log, Giardia cysts and Cryptosporidium oocysts reductions up to 3.15 log and 2.24 log, respectively. The non-woven blanket was shown as an important physical barrier to remove solids, E. coli and protozoa.


Asunto(s)
Criptosporidiosis , Cryptosporidium , Agua Potable , Purificación del Agua , Animales , Escherichia coli , Filtración , Abastecimiento de Agua
14.
Water Res ; 178: 115854, 2020 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-32361348

RESUMEN

Supplying safe drinking water in humanitarian emergencies is critical, and source water chlorination is a commonly implemented intervention to provide safe water. We evaluated three different source water chlorination programs (bucket, in-line, and piped water chlorination) in the ongoing humanitarian response in Cox's Bazar refugee camps in Bangladesh. We used a mixed-methods research protocol including key informant interviews, water point observations, focus group discussions, household surveys, and water quality testing. The three evaluated programs were implemented at different response stages and required different levels of staffing, infrastructure, and community mobilization work. In the bucket chlorination program, highly contaminated open well water was chlorinated, in in-line and piped water chlorination programs, groundwater was treated. Overall, 71% of bucket, 36% of in-line, and 60% of piped water chlorination households had stored water that met free chlorine residual (FCR) criteria, respectively. Additionally, 71% of bucket, 86% of in-line, and 91% of piped water chlorination households had stored water that met Escherichia coli (E. coli) criteria (<10 E. coli CFU/100 mL). Regression results indicate presence of FCR, serving water by pouring, and higher source water pH were associated with meeting E. coli criteria. Our results highlight: no individual program fully met international standards as implemented, although each partially met standards; the importance of understanding beneficiary preferences and behavior change campaigns; and, the benefits and drawbacks of each source water chlorination program must be considered before implementation. Overall, we found appropriate source water chlorination program choice is a continuum, depending on humanitarian phase and context. Therefore, we recommend continuing context- and phase-appropriate source water chlorination programs, emphasizing consistent and acceptable chlorine dosage, implementing programmatic improvements, and incorporating user preferences to reduce microbial contamination and consequently the risk of waterborne diseases.


Asunto(s)
Agua Potable , Purificación del Agua , Bangladesh , Urgencias Médicas , Escherichia coli , Halogenación , Humanos , Microbiología del Agua , Abastecimiento de Agua
15.
Bioresour Technol ; 310: 123428, 2020 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-32361647

RESUMEN

Bioretention systems improve stormwater infiltration and water quality; however, limited total nitrogen (TN) and fecal indicator bacteria (FIB) removal is observed in sand-based bioretention media. In this study, the fate of nitrogen and E. coli in bioretention systems was investigated through batch and column studies using sand media, with and without biochar addition. Variables investigated included biochar characteristics, hydraulic loading rate (HLR) and antecedent dry period (ADP). Total ammonia nitrogen (TAN), dissolved organic carbon (DOC), and E. coli removals were significantly higher in biochar-amended columns due to biochar's high cation exchange capacity and specific surface area. TAN adsorption resulted in increased nitrification during the ADP when aerobic conditions developed. Moisture content data revealed that saturated conditions prevailed toward the bottom of biochar-amended columns for several days, favoring denitrification and TN removal. Biochar amended columns also showed more stable TAN, DOC and E. coli effluent concentrations under varying HLR and ADP.


Asunto(s)
Escherichia coli , Nitrógeno , Carbón Orgánico , Desnitrificación
16.
Bioresour Technol ; 310: 123459, 2020 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-32389429

RESUMEN

Poultry litter is a potentially valuable crude protein feedstuff for ruminants but must be treated to kill pathogens before being fed. Composting kills pathogens but risks losses of nitrogen due to volatilization or leaching as ammonia. Treatment of poultry litter with ethyl nitroacetate, 3-nitro-1-propionate, ethyl 2-nitropropionate (at 27 µmol/g), decreased numbers of experimentally-inoculated Salmonella Typhimurium (>1.0 log10 compared to controls, 4.2 ± 0.2 log10 CFU/g) but not endogenous Escherichia coli early during simulated composting. By day 9 of simulated composting, Salmonella and E. coli were decreased to non-detectable levels regardless of treatment. Some nitro-treatments preserved uric acid and prevented ammonia accumulation, with 18% more uric acid remaining and 17-24% less ammonia accumulating in some nitro-treated litter than in untreated litter (18.1 ± 3.8 µmol/g and 3.4 ± 1.4 µmol/g, respectively). Results indicate that nitro-treatment may help preserve uric acid in composted litter while aiding Salmonella control.


Asunto(s)
Compostaje , Animales , Escherichia coli , Estiércol , Nitrógeno , Aves de Corral , Salmonella
17.
Mem Inst Oswaldo Cruz ; 115: e190347, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32428188

RESUMEN

BACKGROUND Bacillus Calmette-Guérin (BCG) is considered a promising live bacterial delivery system. However, several proposals for rBCG vaccines have not progressed, mainly due to the limitations of the available expression systems. OBJECTIVES To obtain a set of mycobacterial vectors using a range of promoters with different strengths based on a standard backbone, previously shown to be stable. METHODS Mycobacterial expression vectors based on the pLA71 vector as backbone, were obtained inserting different promoters (PAN, PαAg, PHsp60, PBlaF* and PL5) and the green fluorescence protein (GFP) as reporter gene, to evaluate features such as their relative strengths, and the in vitro (inside macrophages) and in vivo stability. FINDINGS The relative fluorescence observed with the different vectors showed increasing strength of the promoters: PAN was the weakest in both Mycobacterium smegmatis and BCG and PBlaF* was higher than PHsp60 in BCG. The relative fluorescence observed in a macrophage cell line showed that PBlaF* and PHsp60 were comparable. It was not possible to obtain strains transformed with the extrachromosomal expression vector containing the PL5 in either species. MAIN CONCLUSION We have obtained a set of potentially stable mycobacterial vectors with a arrange of expression levels, to be used in the development of rBCG vaccines.


Asunto(s)
Vacuna BCG/inmunología , Escherichia coli/inmunología , Vectores Genéticos/inmunología , Proteínas Fluorescentes Verdes/inmunología , Mycobacterium bovis/inmunología , Mycobacterium smegmatis/inmunología , Animales , Escherichia coli/genética , Femenino , Vectores Genéticos/genética , Ratones , Ratones Endogámicos BALB C
18.
Bioresour Technol ; 311: 123513, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-32417661

RESUMEN

An elastin-like polypeptide (ELP) sequence fused with Lactobacillus sp. B164 ß-galactosidase modified with 6x-Histidine (ß-Gal-LH) to produce recombinant ß-Gal-Linker-ELP-His (ß-Gal-LEH) was expressed in E. coli and purified via inverse thermal cycling (ITC) and nickel-nitrilotriacetic acid (Ni-NTA) resin. The ß-galactosidase integrated with ELP-system showed an improved purification at 1.75 M (NH4)2SO4 after 1 round ITC (95.66% recovery rate and 13.04 purification fold) with better enzyme activity parameters compared to Ni-NTA. The enzyme maintained an optimal temperature (40 °C) and pH (7.5) for both ß-Gal-LEH and ß-Gal-LH. The results further showed that the ELP-fusion system improved the enzyme's thermal and storage stability. Moreover, the enzyme secondary structure was not changed by ELP-tag. Enzyme activity was completely inactivated by Hg2+, Cd2+ and Cu2+, unaffected by Ca2+, EDTA and urea, but partially activated by Mn2+ at lower concentration. Compared to commercial ß-galactosidases, ß-Gal-LEH exhibited similar biocatalytic efficiency on lactose and could potentially catalyze transgalactosylation.


Asunto(s)
Elastina , Lactosa , Escherichia coli , Hidrólisis , Lactobacillus , Péptidos , Proteínas Recombinantes de Fusión , beta-Galactosidasa
19.
Bioresour Technol ; 311: 123523, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-32446237

RESUMEN

This study aimed to investigate; composting of toxic weed Parthenium with cow dung in (2:1, and 1:1 ratio); and the changes in Escherichia coli and Salmonella population; as well as the antimicrobial property of ready compost. Organic carbon decreased by 45-52% while total nitrogen, total potassium, available phosphorus increased by 1.87- to 3.21-, 1.65- to 1.83-, and 4.03- to 3.33-folds, respectively in Parthenium setups. Germination index value (110-132%) indicates no phytotoxicity of composted Parthenium. E. coli reduced by 6.87 to 6.90 log population (<1000 CFU g-1, safe limit) while Salmonella was in non-detectable limit in compost samples. Results of the antimicrobial test indicate a strong biocidal activity by non-sterilized compost extract against plant pathogens Xanthomonas citrus, Xanthomonas campestris, and Erwinia carotovora. Xanthomonas spp. It is concluded that thermophilic composting could convert Parthenium into a product with biomanure and biopesticide property for sustainable agriculture production.


Asunto(s)
Compostaje , Animales , Agentes de Control Biológico , Bovinos , Escherichia coli , Femenino , Nutrientes , Extractos Vegetales , Suelo
20.
J Environ Manage ; 268: 110672, 2020 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-32383646

RESUMEN

Urine concentration (condensation) leads to the inactivation of pathogens in urine owing to a hyperosmotic environment. This study proposed an inactivation kinetic model of Escherichia coli (E. coli), a surrogate of human bacterial pathogens, in concentrated synthetic urine. The model parameters were obtained under an assumption that the inactivation rate of E. coli followed a binomial distribution, which made it possible to accurately simulate the time-course decay of E. coli in synthetic urine. The inactivation rate constant values obtained in concentrated urine samples, ammonium buffer solutions and carbonate buffer solutions indicated that the osmotic pressure was a relatively predominant cause for the inactivation of E. coli. The appropriate storage time was estimated using the approach of quantitative microbial risk assessment, which indicated that the 5-fold concentrated urine could be safely collected after 1-day storage when urea was hydrolyzed, whereas 91-hour storage was required for non-concentrated urine. The occupational risk was not negligible even with 6-month storage at 20 °C when urea was not hydrolyzed, which suggested that the urine storage styles should be clarified more minutely. The present study highlights the importance of "predictive environmental microbiology," which deals with inactivation kinetic models of microorganisms under varied environmental conditions to fully implement the hazard analysis and critical control point (HACCP) approach for the safe use of human excreta in agriculture.


Asunto(s)
Escherichia coli , Saneamiento , Microbiología Ambiental , Microbiología de Alimentos , Humanos , Cinética , Temperatura
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