Constructed wetlands (CW) are a low-cost alternative for wastewater treatment, where microbial communities play a key role in the biotransformation of pollutants, including sulfur compounds. This study reports the identification of cultivable bacteria involved in the sulfur cycle (SC) in a subsurface-flow CW located in Tetipac, Mexico. Water, sediment, and rhizosphere samples were collected during four sampling events and plated on a mineral medium with thiosulfate. Colony-forming units were quantified, and 15 isolates were genetically identified by partial 16S rRNA gene sequencing. Bacterial abundance was higher in the rhizosphere, and the cultivable fraction was dominated by Pseudomonadota, particularly Gammaproteobacteria, accompanied by Bacteroidota and several previously uncultured lineages; genera such as Achromobacter, Chitinophaga, Enterobacter, Pseudomonas, Raoultella and Stenotrophomonas were recovered. Biochemical assays revealed heterogeneous metabolic profiles, with several isolates showing activities comparable to canonical sulfur-oxidizing bacteria (SOB). Most isolates oxidized thiosulfate and a substantial proportion oxidized elemental sulfur, with higher metabolic performance in rhizosphere isolates and a positive association with BOD₅ removal. Overall, these results indicate that the Tetipac wetland harbors a cultivable community of largely non-canonical SOB whose mixotrophic versatility and spatial differentiation suggest a key contribution to the SC and organic matter degradation in CW.

During the 2012 highly pathogenic avian influenza outbreak in Mexico caused by the H7N3 subtype, infection led to the death of approximately 22 million laying hens. Thus, poultry farmers were faced with a challenge to ensure the continued commercial flow of eggs. In addition to implementing established sanitary protocols and vaccination programs, forced moulting management was utilized in the affected areas. This strategy guaranteed the maintenance of egg production in the quarantined areas by decreasing the mortality of the infected flock while re-stimulating egg production. To understand how forced moulting reduced mortality of the infected birds, we examined the distribution of the avian influenza receptor in the oviduct of hens subjected to forced moulting. We tested if changes in the reproductive tract caused by forced moulting generated a decrease in the expression of the specific virus receptor in the cell membranes. Host susceptibility to the influenza virus was determined by the presence of these specific receptors. We utilized immunofluorescence of the Maackia amurensis lectin to identify the presence of the virus receptor in histological sections of the oviducts of birds in egg production and birds undergoing forced moulting. The results showed the presence and distribution of the receptors for avian influenza. A strong signal of the receptor was observed in the histological sections of the oviducts of birds in egg production. Conversely, the signal was low in the oviducts of birds undergoing forced moulting. These results demonstrate a decrease in the number of receptors of birds subjected to forced moulting. A lack of receptors would affect virus infection and replication as well as virus-induced damage in the oviduct, which may help explain the observation in the field that birds infected with avian influenza and subjected to forced moulting have decreased mortality.A. Abundant amount of influenza-like receptors, labelled with apple-green fluorescence, on the apical region of the ciliated cylindrical pseudostratifiedepithelium of the uterine region of healthy hens in production. Bar: 100 μm.

Constructed wetlands (CW) are a low-cost alternative for wastewater treatment, where microbial communities play a key role in the biotransformation of pollutants, including sulfur compounds. This study reports the identification of cultivable bacteria involved in the sulfur cycle (SC) in a subsurface-flow CW located in Tetipac, Mexico. Water, sediment, and rhizosphere samples were collected during four sampling events and plated on a mineral medium with thiosulfate. Colony-forming units were quantified, and 15 isolates were genetically identified by partial 16S rRNA gene sequencing. Bacterial abundance was higher in the rhizosphere, and the cultivable fraction was dominated by Pseudomonadota, particularly Gammaproteobacteria, accompanied by Bacteroidota and several previously uncultured lineages; genera such as Achromobacter, Chitinophaga, Enterobacter, Pseudomonas, Raoultella and Stenotrophomonas were recovered. Biochemical assays revealed heterogeneous metabolic profiles, with several isolates showing activities comparable to canonical sulfur-oxidizing bacteria (SOB). Most isolates oxidized thiosulfate and a substantial proportion oxidized elemental sulfur, with higher metabolic performance in rhizosphere isolates and a positive association with BOD₅ removal. Overall, these results indicate that the Tetipac wetland harbors a cultivable community of largely non-canonical SOB whose mixotrophic versatility and spatial differentiation suggest a key contribution to the SC and organic matter degradation in CW.

The COVID-19 pandemic caused by the coronavirus SARS-CoV-2 has proven the need for developing reliable and affordable technologies to detect pathogens. Particularly, the detecting the genome in wastewater could be an indicator of the transmission rate to alert on new outbreaks. However, wastewater-based epidemiology remains a technological challenge to develop affordable technologies for sensing pathogens. In this work, we introduce a label-free and portable field-effect transistor (FET)-based sensor to detect N and ORF1ab genes of the SARS-CoV-2 genome. Our sensor integrates the reverse transcription loop-mediated isothermal amplification (RT-LAMP) reaction as a cost-effective molecular detection exhibiting high specificity. The detection relies upon pH changes, due to the RT-LAMP reaction products, which are detected through a simple, but effective, extended-gate FET sensor (EGFET). We evaluate the proposed device by measuring real wastewater samples to detect the presence of SARS-CoV-2 genome, achieving a limit of detection of 0.31×10−3 ng/µL for end-point measurement. Moreover, we find the ability of the sensor to perform real-time-like analysis, showing that the RT-LAMP reaction provides a good response after 15 minutes for concentrations as low as 0.37 ng/µL. Hence, we show that our EGFET sensor offers a powerful tool to detect the presence of the SARSCoV-2 genome with a naked-eye method, in a straightforward way than the conventional molecular methods for wastewater analysis.