Development and evaluation of a colorimetric LAMP based-assay targeting the Bacteroides HF183 marker for tracking sewage pollution in environmental waters.

Surface waters are vulnerable to contamination by human and animal feces, posing risks to human health due to potential exposure to enteric pathogens. This research developed a colorimetric loop-mediated isothermal amplification (cLAMP) assay to detect sewage associated Bacteroides dorei HF183/BacR287 (HF183) marker in wastewater and environmental water samples. The host sensitivity and host specificity of the assay were evaluated, and their performance was compared to the Bacteroides HF183 qPCR assay using control materials (gBlocks), environmental water samples seeded with untreated sewage, and ambient environmental water samples. In serial dilutions of control materials, qPCR produced quantifiable data across all dilutions, while cLAMP detected the marker down to 0.001 pg/µL of control materials, which was two orders of magnitude less sensitive than qPCR. All untreated sewage samples (n = 12) tested positive for HF183 by both the qPCR and cLAMP assays, demonstrating a host sensitivity value of 1.00 (maximum value of 1.00). The host specificity by analysing 70 non-human fecal nucleic acid samples revealed cLAMP's specificity value of 0.81 compared to qPCR's 0.64. When testing sewage-seeded environmental water samples, both methods detected HF183 for the lowest amount of sewage, indicating similar detection sensitivity. The application of cLAMP for tracking sewage pollution in environmental waters showed promising results, with moderate agreement between cLAMP and qPCR (κ = 0.510). However, cLAMP occasionally missed detections compared to qPCR, particularly in low-concentration samples. Overall, the cLAMP HF183 assay demonstrated promising potential as a rapid and sensitive method for detecting sewage pollution, offering a viable alternative to qPCR in certain environmental monitoring scenarios.

Resistance to glufosinate is proportional to phosphinothricin acetyltransferase expression and activity in LibertyLink(®) and WideStrike(®) cotton.

MAIN CONCLUSION: Insertion of the gene encoding phosphinothricin acetyltransferase (PAT) has resulted in cotton plants resistant to the herbicide glufosinate. However, the lower expression and commensurate reduction in PAT activity is a key factor in the low level of injury observed in the WideStrike(®) cotton and relatively high level of resistance observed in LibertyLink(®) cotton. LibertyLink(®) cotton cultivars are engineered for glufosinate resistance by overexpressing the bar gene that encodes phosphinothricin acetyltransferase (PAT), whereas the insect-resistant WideStrike(®) cultivars were obtained using the similar pat gene as a selectable marker. The latter cultivars carry some level of resistance to glufosinate which enticed certain farmers to select this herbicide for weed control with WideStrike(®) cotton. The potency of glufosinate on conventional FM 993, insect-resistant FM 975WS, and glufosinate-resistant IMACD 6001LL cotton cultivars was evaluated and contrasted to the relative levels of PAT expression and activity. Conventional cotton was sensitive to glufosinate. The single copy of the pat gene present in the insect-resistant cultivar resulted in very low RNA expression of the gene and undetectable PAT activity in in vitro assays. Nonetheless, the presence of this gene provided a good level of resistance to glufosinate in terms of visual injury and effect on photosynthetic electron transport. The injury is proportional to the amount of ammonia accumulation. The strong promoter associated with bar expression in the glufosinate-resistant cultivar led to high RNA expression levels and PAT activity which protected this cultivar from glufosinate injury. While the insect-resistant cultivar demonstrated a good level of resistance to glufosinate, its safety margin is lower than that of the glufosinate-resistant cultivar. Therefore, farmers should be extremely careful in using glufosinate on cultivars not expressly designed and commercialized as resistant to this herbicide.

Aplicação de genes marcadores em estudos de ecologia microbiana com ênfase no sistema GUS

Many of the ecological aspects involved with the interactions between legume species and rhizobia strains have been made easily to understood with the use of reporter gene techniques. The introduction of a specific reporter gene in an organism has shown to be highly efficient to analyze such interactions. These reporter genes generally code for products that can be easily identified or measured, mainly enzymes that can act on a variety of substrates, supplying colored or fluorescent detectable products. In general, the marker genes have been used in different aspects of microbial ecology, as in the competition studies among rhizobia strains, symbiotic gene expression, rhizosphere and root colonization, among others. In all studies, the marker genes need to be introduced into the genome by a plasmid or through a chromosomal insert. The present review focus, mainly, on the diverse use and applications of marker genes on ecological microbial studies with emphasis on the GUS gene system (b-glucuronidase).

Muitos aspectos ecológicos envolvidos nas interações entre espécies leguminosas e estirpes de rizóbio têm sido facilmente entendidos com o emprego de técnicas que utilizam genes marcadores. A introdução de um gene marcador específico tem se mostrado altamente viável para análises dessas interações. Os genes marcadores são capazes de codificar para produtos que podem ser facilmente identificados ou medidos, especialmente, enzimas que podem atuar em diferentes substratos, fornecendo produtos coloridos ou fluorescentes facilmente detectáveis. De uma maneira geral, os genes marcadores têm sido utilizados em diferentes aspectos da ecologia microbiana, como nos estudos de competição entre estirpes de rizóbio, expressão de genes simbióticos, colonização da rizosfera e raízes, entre outros. Em todos esses estudos, os genes repórteres precisam ser introduzidos no genoma alvo através de um plasmídeo ou por inserção cromossomal. Nesta revisão, são enfatizados, principalmente, os diversos usos e aplicações de genes marcadores nos estudos de ecologia microbiana, com ênfase no sistema GUS (b-glucuronidase).

Aplicação de genes marcadores em estudos de ecologia microbiana com ênfase no sistema GUS

Many of the ecological aspects involved with the interactions between legume species and rhizobia strains have been made easily to understood with the use of reporter gene techniques. The introduction of a specific reporter gene in an organism has shown to be highly efficient to analyze such interactions. These reporter genes generally code for products that can be easily identified or measured, mainly enzymes that can act on a variety of substrates, supplying colored or fluorescent detectable products. In general, the marker genes have been used in different aspects of microbial ecology, as in the competition studies among rhizobia strains, symbiotic gene expression, rhizosphere and root colonization, among others. In all studies, the marker genes need to be introduced into the genome by a plasmid or through a chromosomal insert. The present review focus, mainly, on the diverse use and applications of marker genes on ecological microbial studies with emphasis on the GUS gene system (b-glucuronidase).

Muitos aspectos ecológicos envolvidos nas interações entre espécies leguminosas e estirpes de rizóbio têm sido facilmente entendidos com o emprego de técnicas que utilizam genes marcadores. A introdução de um gene marcador específico tem se mostrado altamente viável para análises dessas interações. Os genes marcadores são capazes de codificar para produtos que podem ser facilmente identificados ou medidos, especialmente, enzimas que podem atuar em diferentes substratos, fornecendo produtos coloridos ou fluorescentes facilmente detectáveis. De uma maneira geral, os genes marcadores têm sido utilizados em diferentes aspectos da ecologia microbiana, como nos estudos de competição entre estirpes de rizóbio, expressão de genes simbióticos, colonização da rizosfera e raízes, entre outros. Em todos esses estudos, os genes repórteres precisam ser introduzidos no genoma alvo através de um plasmídeo ou por inserção cromossomal. Nesta revisão, são enfatizados, principalmente, os diversos usos e aplicações de genes marcadores nos estudos de ecologia microbiana, com ênfase no sistema GUS (b-glucuronidase).