Comparative analyses on nitrogen removal microbes and functional genes within anaerobic-anoxic-oxic and deoxidation ditch sewage-treating processes in Wuhan and Xi'an cities, China.

Introduction: Anaerobic-anoxic-oxic (A/O) and deoxidation ditch (DOD) processes are being increasingly preferred owing to their effectiveness in treating various wastes in wastewater treatment plants (WWTPs). Considering seasonal variations is crucial in optimizing treatment processes, ensuring compliance with regulations, and maintaining the overall efficiency and effectiveness of WWTPs. This study aimed to determine the influence of seasonality on nitrogen removing microbes and functional genes within A/O and DOD processes in the humid Wuhan and semi-arid Xi'an cities, China.

Distribution and control mechanism of pCO and water-air CO efflux in the Pearl River Estuary.

Estuaries are generally considered to be important sources of atmospheric CO. However, the differences between estuaries, and inadequate observations of partial pressure of CO in estuarine water (pCO) hamper global estuarine CO budgeting. In this study, the longitudinal distribution of CO in the waters of Modaomen (MSE) and Lingdingyang (LSE), two sub-estuaries of the Pearl River Estuary (PRE), and its influencing mechanism are studied.

The concentration of CH, NO and CO in the Pearl River estuary increased significantly due to the sediment particle resuspension and the interaction of hypoxia.

Hypoxia and sediment particle resuspension (SPR) alter the biogeochemical cycle of estuarine and coastal seas, which in turn affects the production and emission of methane (CH), nitrous oxide (NO) and carbon dioxide (CO) greenhouse gases (GHGs) in estuaries. Despite the importance of CH, NO and CO in estuarine ecosystems, little is known about their magnitude and spatiotemporal variation under the combined influence of hypoxia and SPR. This study utilized continuous mooring observations to investigate the temporal and spatial variations of GHGs before and after hypoxia in the Pearl River Estuary (PRE).

Environmental Contamination of SARS-CoV-2 Delta VOC by COVID-19 Patients Staying in the Hospital for More Than Two Weeks.

Background: Patients infected with SARS-CoV-2 Delta VOC have a longer course of disease. We detected the air, surfaces, and patient's personal items in the wards of the second hospital of Nanjing during the outbreak of the COVID-19 Delta Variant to identify the environmental contamination, which provides a theoretical basis for the prevention and control of COVID-19 variation beads in the future.

Methods: In the cross-sectional study, we collected and analyzed clinical features, demographic and epidemiological data, laboratory and swab test results, and surface and air samples of 144 COVID-19 cases.

Characterization of the Positive Transcription Regulator PfaR for Improving Eicosapentaenoic Acid Production in Shewanella putrefaciens W3-18-1.

The biosynthetic pathway of eicosapentaenoic acid (EPA) has previously been reported in marine bacteria, while the regulatory mechanism remains poorly understood. In this study, a putative transcriptional regulator PfaR encoded adjacent to the PFA biosynthesis gene cluster () was computationally and experimentally characterized. Comparative analyses on the wild type (WT) strain, in-frame deletion, and overexpression mutants revealed that PfaR positively regulated EPA synthesis at low temperature.

Conditional deletion of Hspa5 leads to spermatogenesis failure and male infertility in mice.

Heat shock proteins (HSPs) have important roles in different developmental stages of spermatogenesis. The heat shock 70 kDa protein 5 (HSPA5) is an important component of the unfolded protein response that promotes cell survival under endoplasmic reticulum (ER) stress conditions. In this study, we explored the function of HSPA5 in spermatogenesis, by generating a germ cell-specific deletion mutant of the Hspa5 gene (conditional knockout of the Hspa5 gene, Hspa5-cKO) using CRISPR/Cas9 technology and the Cre/Loxp system.

Pre-meiotic deletion of PEX5 causes spermatogenesis failure and infertility in mice.

Peroxisomes are involved in the regulation of various pathological processes. Peroxisomal biogenesis factor 5 (PEX5), which plays an essential role in peroxisomal biogenesis, is critical for reactive oxygen species (ROS) accumulation. However, its underlying functions in spermatogenesis have not yet been identified.

Spatial distribution and influencing mechanism of CO, NO and CH in the Pearl River Estuary in summer.

Estuaries, considered as the important carbon dioxide (CO), nitrous oxide (NO) and methane (CH) sources to the atmosphere, are increasingly affected by near-bottom hypoxia. However, the impact of estuarine hypoxic zone development on GHGs production and discharge remains poorly understood due to the seasonal and spatially distributed heterogeneity of estuarine hypoxia occurrence and the lack of simultaneous monitoring of the distribution of bottom hypoxic waters and the vertical distribution of GHGs. Here, we conducted high spatial resolution vertical stratification sampling and analysis of water column GHGs in the Pearl River Estuary (PRE), a large estuary with frequent hypoxia in recent years.

gen. nov., sp. nov., a novel member of family , isolated from a water purification facility with supplement of starch as a carbon source.

During a survey of microbial communities in the influent (ambient water) and effluent of a water purification facility with aeration and supplement of starch as carbon source, a novel bacterial strain, designated SZ9, was isolated from the effluent sample. Colonies of strain SZ9 were small (approximately 0.5-1.

Environmental sampling of the severe acute respiratory syndrome coronavirus 2 Delta variant in the inpatient wards of a hospital in Nanjing.

Background: Little is known about severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Delta variant of concern (VOC)-contaminated environmental surfaces and air in hospital wards admitting COVID-19 cases. Our study was designed to identify high-risk areas of Delta VOC contamination in the hospital and provide suggestions to in-hospital infection control. We analyzed the SARS-CoV-2 Delta VOC contamination in the air and environmental surface samples collected from a hospital in Nanjing, China.

Tropical and temperate wastewater treatment plants assemble different and diverse microbiomes.

The diversity and assembly of activated sludge microbiomes play a key role in the performances of municipal wastewater treatment plants (WWTPs), which are the most widely applied biotechnological process systems. In this study, we investigated the microbiomes of municipal WWTPs in Bangkok, Wuhan, and Beijing that respectively represent tropical, subtropical, and temperate climate regions, and also explored how microbiomes assembled in these municipal WWTPs. Our results showed that the microbiomes from these municipal WWTPs were significantly different.

Dissimilatory Nitrate Reduction to Ammonium (DNRA) and Denitrification Pathways Are Leveraged by Cyclic AMP Receptor Protein (CRP) Paralogues Based on Electron Donor/Acceptor Limitation in Shewanella loihica PV-4.

Under anoxic conditions, many bacteria, including strain PV-4, could use nitrate as an electron acceptor for dissimilatory nitrate reduction to ammonium (DNRA) and/or denitrification. Previous and current studies have shown that DNRA is favored under higher ambient carbon-to-nitrogen (C/N) ratios, whereas denitrification is upregulated under lower C/N ratios, which is consistent with our bioenergetics calculations. Interestingly, computational analyses indicate that the common cyclic AMP receptor protein (designated CRP1) and its paralogue CRP2 might both be involved in the regulation of two competing dissimilatory nitrate reduction pathways, DNRA and denitrification, in PV-4 and several other denitrifying species.

sp. nov., a novel member of isolated from activated sludge collected in Hong Kong.

A floc-forming bacterial strain, designated HKLI-1, was isolated from the activated sludge of a municipal sewage treatment plant in Hong Kong SAR, PR China. Cells of this strain were Gram-stain-negative, strictly aerobic, catalase- and oxidase-positive, rod-shaped and motile by means of a single polar flagellum. Growth occurred at 18-37 °C (optimum, 28 °C), pH 5.

Production of Highly Active Extracellular Amylase and Cellulase From ZIM3 and a Recombinant Strain With a Potential Application in Tobacco Fermentation.

In this study, a series of bacteria capable of degrading starch and cellulose were isolated from the aging flue-cured tobacco leaves. Remarkably, there was a thermophilic bacterium, ZIM3, that can simultaneously degrade both starch and cellulose at a wide range of temperature and pH values. Genome sequencing, comparative genomics analyses, and enzymatic activity assays showed that the ZIM3 strain expressed a variety of highly active plant biomass-degrading enzymes, such as the amylase AmyE1 and cellulase CelE1.

Differential gene content and gene expression for bacterial evolution and speciation of Shewanella in terms of biosynthesis of heme and heme-requiring proteins.

Background: Most species of Shewanella harbor two ferrochelatase paralogues for the biosynthesis of c-type cytochromes, which are crucial for their respiratory versatility. In our previous study of the Shewanella loihica PV-4 strain, we found that the disruption of hemH1 but not hemH2 resulted in a significant accumulation of extracellular protoporphyrin IX (PPIX), but it is different in Shewanella oneidensis MR-1. Hence, the function and transcriptional regulation of two ferrochelatase genes, hemH1 and hemH2, are investigated in S.

Both widespread PEP-CTERM proteins and exopolysaccharides are required for floc formation of Zoogloea resiniphila and other activated sludge bacteria.

Bacterial floc formation plays a central role in the activated sludge (AS) process, which has been widely utilized for sewage and wastewater treatment. The formation of AS flocs has long been known to require exopolysaccharide biosynthesis. This study demonstrates an additional requirement for a PEP-CTERM protein in Zoogloea resiniphila, a dominant AS bacterium harboring a large exopolysaccharide biosynthesis gene cluster.

Effects of Planted Versus Naturally Growing Vallisneria natans on the Sediment Microbial Community in West Lake, China.

Submerged macrophytes play an important role in aquatic ecosystems, which has led to an increase in studies on vegetation recovery in polluted lakes from which submerged macrophytes have disappeared. The comparison of microbial communities in sediment cloned with planted and naturally growing submerged macrophytes is an interesting but rarely studied topic. In this investigation, Maojiabu and Xilihu, two adjacent sublakes of West Lake (Hangzhou, China), were selected as aquatic areas with planted and naturally growing macrophytes, respectively.

EPS solubilization treatment by applying the biosurfactant rhamnolipid to reduce clogging in constructed wetlands.

Application of extracellular polymeric substances (EPS) solubilization treatment with biosurfactant rhamnolipid (RL) to reduce clogging in constructed wetlands was first conducted in this study. The results showed significant improvement in the solubilization and dispersion of clogging matter following the treatment. And RL dosage of 0.