RESUMO
Gut damage during carbapenem-resistant and hypervirulent Klebsiella pneumoniae (CR-HvKP) infection is associated with a death risk. Understanding the mechanisms by which CR-HvKP causes intestinal damage and gut microbiota alteration, and the impact on immunity, is crucial for developing therapeutic strategies. This study investigated if gastrointestinal tract damage and disruption of gut microbiota induced by CR-HvKP infection undermined host immunity and facilitated multi-organ invasion of CR-HvKP; whether the therapeutic value of the rifampicin (RIF) and zidovudine (ZDV) combination was attributed to their ability to repair damages and restore host immunity was determined. A sepsis model was utilized to assess the intestinal pathological changes. Metagenomic analysis was performed to characterize the alteration of gut microbiota. The effects of the RIF and ZDV on suppressing inflammatory responses and improving immune functions and gut microbiota were evaluated by immunopathological and transcriptomic analyses. Rapid colonic damage occurred upon activation of the inflammation signaling pathways during lethal infections. Gut inflammation compromised host innate immunity and led to a significant decrease in probiotics abundance, including Bifidobacterium and Lactobacillus. Treatment with combination drugs significantly attenuated the inflammatory response, up-regulated immune cell differentiation signaling pathways, and promoted the abundance of Bifidobacterium (33.40â¯%). Consistently, supplementation of Bifidobacterium alone delayed the death in sepsis model. Gut inflammation and disrupted microbiota are key disease features of CR-HvKP infection but can be reversed by the RIF and ZDV drug combination. The finding that these drugs can restore host immunity through multiple mechanisms is novel and deserves further investigation of their clinical application potential.
Assuntos
Microbioma Gastrointestinal , Infecções por Klebsiella , Klebsiella pneumoniae , Rifampina , Microbioma Gastrointestinal/efeitos dos fármacos , Animais , Infecções por Klebsiella/tratamento farmacológico , Infecções por Klebsiella/imunologia , Infecções por Klebsiella/mortalidade , Infecções por Klebsiella/microbiologia , Klebsiella pneumoniae/efeitos dos fármacos , Rifampina/uso terapêutico , Rifampina/farmacologia , Masculino , Zidovudina/uso terapêutico , Antibacterianos/uso terapêutico , Antibacterianos/farmacologia , Intestinos/microbiologia , Intestinos/patologia , Intestinos/efeitos dos fármacos , Intestinos/imunologia , Camundongos Endogâmicos C57BL , Sepse/tratamento farmacológico , Sepse/microbiologia , Sepse/imunologia , Sepse/mortalidade , Camundongos , Imunidade Inata/efeitos dos fármacosRESUMO
Antibiotic contamination has become an increasingly important environmental problem as a potentially hazardous emergent and recalcitrant pollutant that poses threats to human health. In this study, manganese peroxidase displayed on the outer membrane of Escherichia coli as a whole-cell biocatalyst (E. coli MnP) was expected to degrade antibiotics. The manganese peroxidase activity of the whole-cell biocatalyst was 13.88 ± 0.25â¯U/L. The typical tetracycline antibiotic chlortetracycline was used to analyze the degradation process. Chlortetracycline at 50â¯mg/L was effectively transformed via the whole-cell biocatalyst within 18â¯h. After six repeated batch reactions, the whole-cell biocatalyst retained 87.2â¯% of the initial activity and retained over 87.46â¯% of the initial enzyme activity after storage at 25°C for 40 days. Chlortetracycline could be effectively removed from pharmaceutical and livestock wastewater by the whole-cell biocatalyst. Thus, efficient whole-cell biocatalysts are effective alternatives for degrading recalcitrant antibiotics and have potential applications in treating environmental antibiotic contamination.
Assuntos
Antibacterianos , Clortetraciclina , Escherichia coli , Águas Residuárias , Poluentes Químicos da Água , Águas Residuárias/química , Antibacterianos/química , Poluentes Químicos da Água/análise , Peroxidases/metabolismo , Biodegradação Ambiental , Biocatálise , Eliminação de Resíduos Líquidos/métodosRESUMO
Cadmium (Cd) is a hazardous metal that can accumulate in aquatic organisms and endanger human health via the food chain. In this study, genetic engineering was used to display a peptide with Cd-binding potential on the surface of Escherichia coli cells. This whole-cell adsorbent exhibited high affinity for Cd ions (Cd2+) in the solution. The Cd2+ adsorption capacity of the whole-cell adsorbent was three-fold that of the control cells in a 20 µM Cd2+ solution, and 97.2% ± 2.38% of the Cd2+ was removed. The whole-cell adsorbent was fed to shrimp (Neocaridina denticulata), and the surface-engineered E. coli successfully colonized the shrimp intestine, which showed significantly less Cd accumulation than the group not fed surface-engineered E. coli. The whole-cell adsorbent evidently protected shrimp from the toxicity of Cd2+ by adsorbing it. Moreover, the whole-cell adsorbent mitigated the changes in microbial community structure in the shrimp gut caused by the exposure of Cd2+. These findings suggest that this strategy is effective for controlling the contamination of Cd2+ in shrimp.
Assuntos
Cádmio , Decápodes , Animais , Humanos , Cádmio/toxicidade , Escherichia coli/genética , Peptídeos , Metais , AdsorçãoRESUMO
Real-time temperature feedback in tissue based on photothermal therapy is an urgent problem to be solved in cancer treatment. Herein, a smart all-in-one nanoprobe THA@Eu-NMOF@Fe/TA was designed and assembled by postsynthetical functionalization of an Eu(III)-based nanoscale metal-organic framework (Eu-NMOF) with a two-photon-absorbing ß-diketonate ligand 4,4,4-trifluoro-1-(9-hexylcarbazol-3-yl)-1,3-butanedione (HTHA) and Fe(III)/tannic acid assembly (Fe/TA). Such a functionalized material can simultaneously achieve the temperature-sensing and optical heating under a single beam of near-infrared (NIR) light. Under 808 nm laser excitation, real-time feedback of temperature by monitoring thermoresponsive fluorescence emission ratio ( I616/ I590) and fluorescence lifetime of Eu(III) ions were realized. Meantime, Fe/TA served as the photothermal agent and antibacterial agent to implement photothermal therapy (PTT) and antibacteria simultaneously. The functions of the nanoprobe were proved with ex vivo experiments, and the antibacterial activity against Gram-positive and Gram-negative bacteria of the probe was also elaborately evaluated. Our work paves a new avenue for engineering a new cancer treatment probe which can achieve real-time temperature sensing feedback during PTT and antibacterial process.
Assuntos
Antibacterianos/farmacologia , Európio/farmacologia , Estruturas Metalorgânicas/farmacologia , Nanopartículas/química , Termômetros , Antibacterianos/síntese química , Antibacterianos/química , Európio/química , Compostos Férricos/química , Compostos Férricos/farmacologia , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Humanos , Estruturas Metalorgânicas/síntese química , Estruturas Metalorgânicas/química , Testes de Sensibilidade Microbiana , Tamanho da Partícula , Fototerapia , Propriedades de Superfície , Taninos/química , Taninos/farmacologiaRESUMO
Black soldier fly (Hermetia illucens L) larvae (BSFL) possess remarkable antibiotic degradation abilities due to their robust intestinal microbiota. However, the response mechanism of BSFL intestinal microbes to the high concentration of antibiotic stress remains unclear. In this study, we investigated the shift in BSFL gut microbiome and the functional genes that respond to 1250 mg/kg of tetracycline via metagenomic and metatranscriptomic analysis, respectively. The bio-physiological phenotypes showed that the survival rate of BSFL was not affected by tetracycline, while the biomass and substrate consumption of BSFL was slightly reduced. Natural BSFL achieved a 20% higher tetracycline degradation rate than the germ-free BSFL after 8 days of rearing. Metagenomic and metatranscriptomic sequencing results revealed the differences between the entire and active microbiome. Metatranscriptomic analysis indicated that Enterococcus, Vagococcus, Providencia, and Paenalcaligenes were the active genera that responded to tetracycline. Furthermore, based on the active functional genes that responded to tetracycline pressure, the response mechanisms of BSFL intestinal microbes were speculated as follows: the Tet family that mediates the expression of efflux pumps expel tetracycline out of the microbes, while tetM and tetW release it from the ribosome. Eventually, tetracycline was degraded by deacetylases and novel enzymes. Overall, this study provides novel insights about the active intestinal microbes and their functional genes in insects responding to the high concentration of antibiotics.
RESUMO
Microbial fuel cell (MFC) is a recommended treatment to remediate hexavalent chromium (Cr(VI)) in wastewater. In this study, a wood carbon (WC) electrode was introduced in MFC to enhance the Cr(VI) removal efficiency. WC electrode in MFC completely removed Cr(VI) as compared to the carbon cloth (31.12%) and carbon felt (34.83) within 48 h of operation at 20 mg L-1 of Cr(VI) concentration. The maximum power density of WC electrode was 62.59 mW m-2 higher than 0.115 and 3.154 mW m-2 of carbon cloth and felt respectively. The specific surface area of WC increased to 158.47 m-2 g-1 after high-temperature carbonization, and electrochemical tests indicate it has higher electrocatalytic ability. Therefore, WC might be a good electrode material to effectively remove Cr(VI) and generate bioelectricity simultaneously.
Assuntos
Fontes de Energia Bioelétrica , Carbono , Cromo , Eletricidade , Eletrodos , Águas Residuárias , MadeiraRESUMO
Insects are a potential alternative protein source to solve the food shortage crisis. Previous studies have illustrated that probiotics can improve the substrate conversion efficiency of insects and increase insect protein content. However, the effects of probiotics on insect physiology and nutrient metabolism are still not well understood. Here, the black soldier fly larvae (BSFL), Hermetia illucens (Diptera: Stratiomyidae), was used as a study subject to deeply investigate the specific interaction among a novel probiotic, Bacillus velezensis EEAM 10B (10B), intestinal microbiota, and the host. In this study, the effects of 10B on the survival and physiology of BSFL were first analyzed. It shows that 10B significantly elevated the substrate conversion rate, average dry weight, and protein content of BSFL by 5%, 0.13 g/pc, and 8%, respectively. Then, we assessed the effect of 10B on the microbial community composition in the gut and frass of BSFL using Illumina Miseq sequencing. It shows that 10B significantly altered the microbial composition of the gut, but not that of the frass. Pearson's correlation analysis further showed that the Bacillus, unclassified_of_Caloramatoraceae, and Gracilibacillus were positively correlated with the survival rate, crude protein content, and substrate conversion rate of BSFL. To further investigate the effect of 10B on host metabolism, metabolic analyses on germ-free BSFL, monobacterial intestinal BSFL, and natural BSFL were also performed. The results proved that 10B (i) played a vital role in the survival of BSFL; and (ii) regulated the amino acid synthetic and metabolic process of BSFL, thus leading to the rise of the protein content of BSFL. In addition, vitamin backfill assays verified that the BSFL survival rate was significantly improved by supplying the germ-free BSFL with riboflavin, which further suggests that 10B determines the survival of BSFL via delivering riboflavin. Overall, this study provides a reference for understanding the comprehensive contribution of a specific probiotic to its host.
RESUMO
Selenium levels have a critical impact on livestock and poultry, and selenium nanoparticles (SeNPs) have shown significant efficiency in supplementation. This study identified a high-efficiency selenite reductase, SerV01, in Staphylococcus aureus LZ-01, which can convert Se2O32- to SeNPs. Subsequently, SerV01 was introduced into the intestines of the broilers using the surface display-engineered E. coli Nissle 1917 (EcN). The results showed that the engineered bacteria (EcN-IS) significantly increased the selenium content by 0.87 mg kg-1, 0.52 mg kg-1, and 6.10 mg L-1 in the liver, breast muscle, and serum, respectively. With SeNPs + EcN-IS treatment, glutathione peroxidase and thioredoxin reductase levels reached 0.7536 ± 0.03176 U µL-1 protein and 2.463 ± 0.1685 U µL-1 protein, respectively. With the modified probiotics, the proportion of beneficial intestinal flora increased, with Lactobacillus and Propionibacterium accounting for 75.85% and 0.19%. This technology provides a novel idea to facilitate the exploitation of selenium in broiler diets and improve antioxidant capability.
Assuntos
Selênio , Animais , Galinhas , Escherichia coli , Glutationa Peroxidase , Ácido Selenioso , Selênio/farmacologia , Selenito de Sódio/farmacologiaRESUMO
A plasmid that harbored the virulence factors highly like those of the virulence plasmid commonly found in clinical hypervirulent Klebsiella pneumoniae strains was detected in a foodborne Escherichia coli strain EC1108 and designated p1108-IncFIB. This virulent-like plasmid was found to be common in E. coli from various sources. To understand the contribution of this plasmid to the virulence of E. coli, plasmid p1108-IncFIB in strain EC1108 was first cured to generate strain EC1108-PC. The virulence plasmid p15WZ-82_Vir in Klebsiella pneumoniae strain 15WZ-82 was then transmitted to EC1108-PC to produce the transconjugant, EC1108-PC-TC to assess the contribution of this virulence plasmid to the virulence level of E. coli. During the process of conjugation, p15WZ-82_Vir was found to be evolved into p15WZ-82_int, which underwent homologous recombination with a plasmid encoding a carbapenemase gene, blaNDM-1, p1108-NDM, in EC1108-PC. Comparison between the level of virulence in the EC1108, EC1108-PC-TC, and EC1108-PC through serum and macrophage resistance assay, as well as animal experiments, confirmed that plasmid p1108-IncFIB encoded a high level of virulence in E. coli, yet the fusion plasmid derived from p15WZ-82_Vir did not encode virulence but instead imposed a high fitness cost in the E. coli strain EC1108-PC-TC. These findings indicate that E. coli strains carrying the virulence plasmid p1108-IncFIB in multidrug-resistant (MDR) strains may also impose serious public health threats like that of hypervirulent Klebsiella pneumoniae strains harboring the p15WZ-82_Vir plasmid. IMPORTANCE Acquisition of pLVPK-like virulence plasmid by Klebsiella pneumoniae converts it to hypervirulent K. pneumoniae (HvKP), which has become one of the most important clinical bacterial pathogens. The potential of transmission of this virulence plasmid and its contribution to the virulence of other Enterobacteriaceae, such as E. coli, are not clear yet. In this study, we showed that pLVPK-like virulence plasmid exhibited fitness costs and did not contribute to the virulence in E. coli. However, we identified a novel virulence plasmid, p1108-IncFIB, that encodes similar siderophore genes as those of pLVPK from a foodborne E. coli strain and showed that p1108-IncFIB encoded a high level of virulence in E. coli. BLAST of E. coli genomes from GenBank showed that these siderophore genes were widespread in clinical E. coli strains. Further studies are warranted to understand the impact of this plasmid in the control of clinical infections caused by E. coli.
Assuntos
Infecções por Escherichia coli , Infecções por Klebsiella , Animais , Antibacterianos , Escherichia coli/genética , Infecções por Klebsiella/microbiologia , Klebsiella pneumoniae/genética , Plasmídeos/genética , Sideróforos , Virulência/genética , beta-Lactamases/genéticaRESUMO
Microbial fuel cell (MFC) biosensors are self-sustainable device for monitoring of various substrates; however, for heavy metals detection are still scarce. In this study, E. coli BL21 was engineered to express the zntR, ribB, and oprF genes with PzntA promoter, which could sense zinc (Zn2+) for riboflavin and porin production. The engineered strain produced high levels of riboflavin (2.4-3.6⯵M) and improved cell membrane permeability, with a positive correlation of Zn2+ (0-400⯵M). The strain was then employed in MFC biosensor under the following operational parameters: external resistance 1000â¯Ω, pH 9, and temperature 37⯰C for Zn2+ sensing. The maximum voltages (160, 183, 260, 292, and 342â¯mV) of the constructed MFC biosensor have a linear relationship with Zn2+ concentrations (0, 100, 200, 300, and 400⯵M, respectively) (R2â¯=â¯0.9777). An Android App was developed for the biosensor system that could sense Zn2+ in real-time and in situ. The biosensor was applied to wastewater with different Zn2+ concentrations and the results showed that the detection range for Zn2+ was 20-100⯵M, which covers common Zn2+ safety standards. The results obtained with developed MFC biosensor were comparable to conventional methods such as colorimetric, flame atomic absorption spectroscopy (FAAS), and inductively coupled plasma optical emission spectroscopy (ICP-OES). In summary, MFC biosensor with biosynthetic strain is an efficient and affordable system for real-time monitoring and sensing of heavy metals.
Assuntos
Técnicas Biossensoriais , Metais Pesados/isolamento & purificação , Águas Residuárias/análise , Zinco/isolamento & purificação , Fontes de Energia Bioelétrica , Escherichia coli/genética , Proteínas de Escherichia coli/química , Proteínas de Escherichia coli/genética , Proteínas de Choque Térmico/química , Proteínas de Choque Térmico/genética , Transferases Intramoleculares/química , Transferases Intramoleculares/genética , Metais Pesados/química , Porinas/biossíntese , Regiões Promotoras Genéticas/genética , Riboflavina/biossíntese , Fatores de Transcrição/química , Fatores de Transcrição/genética , Águas Residuárias/química , Zinco/químicaRESUMO
Antibiotics are widely used in livestock and poultry industries, which results in large quantities of antibiotic residues in manure that influences subsequent treatments. In this study, an Escherichia coli strain was engineered to display erythromycin esterase on its cell surface. The engineered strain (E. coli ereA) efficiently degraded erythromycin by opening the macrocyclic 14-membered lactone ring in solution. Erythromycin (50â¯mg/L) was completely degraded in a solution by E. coli ereA (1â¯×â¯109 CFU/mL) within 24â¯h. E. coli ereA retained over 86.7 % of the initial enzyme activity after 40 days of storage at 25⯰C, and 78.5 % of the initial activity after seven repeated batch reactions in solution at 25⯰C. Mice were fed with E. coli ereA and real-time quantitative PCR data showed that E. coli ereA colonized in the mice large intestine. The mice group fed E. coli ereA exhibited 83.13 % decrease in erythromycin levels in their feces compared with the mice group not fed E. coli ereA. E. coli ereA eliminated antibiotics from the source preventing its release into the environment. The surface-engineered strain therefore is an effective alternative agent for treating recalcitrant antibiotics, and has the potential to be applied in livestock and poultry industries.
Assuntos
Antibacterianos/farmacologia , Hidrolases de Éster Carboxílico/metabolismo , Eritromicina/farmacologia , Escherichia coli/metabolismo , Fezes/química , Microrganismos Geneticamente Modificados/metabolismo , Animais , Hidrolases de Éster Carboxílico/genética , Escherichia coli/genética , Feminino , Genes Bacterianos , Intestinos , CamundongosRESUMO
Biodegradation of recalcitrant organic compounds in microbial fuel cell (MFC) is limited, due to its strong electron affinity and persisted in anaerobic condition. In this study, Pseudomonas monteilii LZU-3 degraded p-nitrophenol (PNP) and generated current at 100â¯mgâ¯L-1 of PNP in anode MFC with the addition of oxygen. The highest PNP degradation was 4, 37.75, and 99.89% in anaerobic, aerobic, and aerated anode of MFC respectively, at 7â¯h. The maximum voltage generation in aerated anode was 183â¯mV, which was comparatively higher than aerobic (150â¯mV) and anaerobic (68â¯mV). The qRT-PCR results confirmed that the oxygenase genes in strain LZU-3 were up-regulated from 17.51 to 39.39-fold at 1.6-4.5â¯mgâ¯L-1 of oxygen concentrations resulted in PNP degradation in anode MFC. This study demonstrated that supplementation of oxygen into the anode MFC might be a potential approach for biodegradation of recalcitrant compounds and electricity generation.