Application of Polyaluminium Chloride Coagulant in Urban River Water Treatment Influenced the Microbial Community in River Sediment

Polyaluminium chloride (PAC) has been widely used as a chemical coagulant in water treatment. However, little is known about the impact of PAC performance on the microbial community in sediments. In this study, the archaeal, bacterial, and fungal communities in urban river sediments with and without PAC treatment were investigated. Prokaryotic diversity decreased at the PAC addition site (A2) and increased along with the river flow (from A3 to A4), while eukaryotic diversity was the opposite. The abundance of core microbiota showed a similar trend. For example, the dominant Proteobacteria presented the highest relative abundance in A1 (26.8%) and the lowest in A2 (15.3%), followed by A3 (17.5%) and A4 (23.0%). In contrast, Rozellomycota was more dominant in A2 (56.6%) and A3 (58.1%) than in A1 (6.2%) and A4 (16.3%). Salinity, total dissolved solids, and metal contents were identified as the key physicochemical factors affecting the assembly of core microorganisms. The predicted functions of archaea and fungi were mainly divided into methane cycling and saprotrophic nutrition, respectively, while bacterial function was more diversified. The above findings are helpful to enhance our understanding of microorganism response to PAC and have significance for water treatment within the framework of microecology.

Black Soldier Fly Larvae Can Effectively Degrade Oxytetracycline Bacterial Residue by Means of the Gut Bacterial Community

Antibiotic bacterial residue is a unique hazardous waste, and its safe and effective disposal has always been a concern of pharmaceutical enterprises. This report presents the effective treatment of hazardous waste—antibiotic bacterial residue—by black soldier fly larvae (larvae), oxytetracycline bacterial residue (OBR), and soya meal with mass ratios of 0:1 (soya), 1:20 (OBRlow), and 1:2 (OBRhigh), which were used as substrates for larval bioconversion. Degradation of OBR and oxytetracycline, the bacterial community, the incidence of antibiotic resistance genes (ARGs) and the bacterial function in the gut were examined. When the larvae were harvested, 70.8, 59.3, and 54.5% of the substrates had been consumed for soya, OBRlow and OBRhigh; 65.9 and 63.3% of the oxytetracycline was degraded effectively in OBRlow and OBRhigh, respectively. The larval bacterial communities were affected by OBR, abundant and various ARGs were discovered in the gut, and metabolism was the major predicted function of the gut. These findings show that OBR can be digested and converted by larvae with gut bacteria, and the larvae can be used as a bioremediation tool for the treatment of hazardous waste. Finally, the abundant ARGs in the gut deserve further attention and consideration in environmental health risk assessments.

Synthesis, Characterization, and Molecular Docking Against a Receptor Protein FimH of Escherichia coli (4XO8) of Thymidine Derivatives

Thymidine is known as a progenitor of nucleosides that have significant biological activity. The widening importance of nucleoside derivatives as unrivaled potential antimicrobial and therapeutic agents has attracted contemplation to the synthesis of thymidine derivatives. In the present study, thymidine was treated with various acyl halides to produce 5ʹ-O-acyl thymidine derivatives by direct acylation method with an excellent yield. To obtain newer products for antimicrobial assessment studies, the 5ʹ-O-thymidine derivatives were further modified into three series of 3ʹ-O-acyl thymidine derivatives containing a wide variety of functionalities in a single molecular framework. The chemical structures of the newly synthesized compounds were elucidated by analyzing their physicochemical, elemental, and spectroscopic data. Additionally, the X-ray powder diffraction (XRD) of these acylated products was studied. For the computational investigation, we have selected eight synthesized thymidine derivatives, which have notable antibacterial activity, and performed molecular docking against bacterial lectin protein FimH of Escherichia coli (4XO8) to suggest a potent inhibitor against bacterial function. Molecular docking was performed using AutoDock Vina to calculate the binding affinities and interactions between the antibacterials and the FimH E. coli (4XO8). It was found that the selected thymidine derivatives have strongly interacted mainly with Tyr48, Tyr137, Asp140, Arg98, Gln133, Phe1, Asn23, Asn135, Lys76, Asp47, Ile13, and Ile52 residues. In silico pharmacokinetic properties were also predicted to search their absorption, metabolism, excretion, and toxicity. This computational examination showed that these thymidine derivatives might be used as potential inhibitors against the promising antibacterial activity for future studies. Resumen. Se prepararon varios derivados 5ʹ-O-acil timidínicos por acilación directa con rendimientos excelentes que fueron transformados en tres series de derivados 3ʹ-O-acil timidínicos con una amplia variedad de funcionalidades. Estos compuestos fueron la base de un estudio de docking dirigido a la lectina bacteriana FimH de Escherichia coli (4XO8) con la finalidad de proponer un inhibidor contra esta función bacteriana.

In situ reprogramming of gut bacteria by oral delivery

Abundant links between the gut microbiota and human health indicate that modification of bacterial function could be a powerful therapeutic strategy. The inaccessibility of the gut and inter-connections between gut bacteria and the host make it difficult to precisely target bacterial functions without disrupting the microbiota and/or host physiology. Herein we describe a multidisciplinary approach to modulate the expression of a specific bacterial gene within the gut by oral administration. We demonstrate that an engineered temperate phage λ expressing a programmable dCas9 represses a targeted E. coli gene in the mammalian gut. To facilitate phage administration while minimizing disruption to host processes, we develop an aqueous-based encapsulation formulation with a microbiota-based release mechanism and show that it facilitates oral delivery of phage in vivo. Finally we combine these technologies and show that bacterial gene expression in the mammalian gut can be precisely modified in situ with a single oral dose.

In situ reprogramming of gut bacteria by oral delivery

Abundant links between the gut microbiota and human health indicate that the modification of bacterial function could be a powerful therapeutic strategy. The inaccessibility of the gut and inter-connections between gut bacteria and the host make it difficult to precisely target bacterial functions without disrupting the microbiota and/or host physiology. Herein we describe a multidisciplinary approach to modulate the expression of a specific bacterial gene within the gut by oral administration. We first demonstrate that an engineered temperate phage λ expressing a programmable dCas9 represses a targeted E. coli gene in the mammalian gut. To facilitate phage administration while minimizing disruption to host processes, we develop an aqueous-based encapsulation formulation with a microbiota-based release mechanism and show that it facilitates the oral delivery of phage in vivo. Finally we combine these technologies and show that bacterial gene expression in the mammalian gut can be precisely modified in situ with a single oral dose.

Stable Neutralization of a Virulence Factor in Bacteria Using Temperate Phage in the Mammalian Gut

ABSTRACT Elimination or alteration of select members of the gut microbiota is key to therapeutic efficacy. However, the complexity of these microbial inhabitants makes it challenging to precisely target bacteria. Here, we deliver exogenous genes to specific bacteria by genomic integration of temperate phage for long-lasting modification. As a real-world therapeutic test, we engineered λ phage to transcriptionally repress Shiga toxin by using genetic hybrids between λ and other lambdoid phages to overcome resistance encoded by the virulence-expressing prophage. We show that a single dose of engineered phage propagates throughout the bacterial community and reduces Shiga toxin production in an enteric mouse model of infection without markedly affecting bacterial concentrations. Our work reveals a new framework for transferring functions to bacteria within their native environment. IMPORTANCE With the increasing frequency of antibiotic resistance, it is critical to explore new therapeutic strategies for treating bacterial infections. Here, we use a temperate phage, i.e., one that integrates itself into the bacterial genome, to neutralize the expression of a virulence factor by modifying bacterial function at the genetic level. We show that Shiga toxin production can be significantly reduced in vitro and in the mammalian gut. Alternative to traditional applications of phage therapy that rely on killing bacteria, our genetics-based antivirulence approach introduces a new framework for treating bacterial infections.