Haihan Zhang

Drinking water odor pollution and pipeline corrosion seriously threaten drinking water safety. Odor-producing algae can penetrate conventional water treatment processes and enter drinking water distribution networks, causing prominent water quality risks. Taking Microcystis aeruginosa as the target alga, this study investigated the effects and underlying mechanisms of pipeline corrosion products (CPs) on the formation of algal odorants under chlorination conditions. The results show that the coexisting system of CPs and chlorine significantly promotes the release of β-cyclocitral from M. aeruginosa while reducing the rupture rate of algal cells. The underlying reason is that CPs consume chlorine in the system, lowering the actual chlorine exposure dose and alleviating oxidative damage to algal cells. Meanwhile, the coexistence of CPs and chlorine may induce oxidative stress in algal cells, potentially further affecting the synthesis and release of β-cyclocitral by M. aeruginosa. Transcriptomic analysis reveals that, in the coexistence system of chlorine and CPs, M. aeruginosa upregulates the expression of genes related to the biosynthesis of the precursor β-carotene, further driving β-cyclocitral production. This study first confirms the synergistic effect between pipeline corrosion and chlorination, which aggravates algal odor pollution. The elucidated underlying mechanism provides a new theoretical basis for the precise control of odor risks in drinking water distribution networks.

Livestock manure is a prominent One Health setting for antimicrobial resistance (AMR), yet the contribution of viruses to resistome assembly remains unresolved. Here we compile the Livestock Manure Virus Database (LMVD), a global catalog of 1,330,372 viral operational taxonomic units reconstructed from 4,017 metagenomes. Livestock manure viral communities exhibit restricted biogeographic distributions, and antibiotic use and farming scale show the highest relative predictive importance for viral diversity. Viral genomes contained 78 antibiotic resistance gene (ARG) subtypes, representing 9.1% of resistome diversity in livestock manure, but virus-encoded ARGs were infrequent. Bacteriophages instead showed extensive predicted links to bacterial hosts, with nearly all antibiotic-resistant bacteria linked to viruses, predominantly temperate viruses, and enrichment in pathogenic antibiotic-resistant bacteria. Together, these findings place bounds on the contribution of viruses to direct ARG dissemination and indicate that lysogenic interactions with resistant hosts may shape AMR risk.