Impact of anaerobically digested silver and copper oxide nanoparticles in biosolids on soil characteristics and bacterial community

This study investigated whether 2 and 30 mg AgNPs or CuONPs/g TS present in treated sludge (biosolids) may impact the soil health by monitoring the soil characteristics and soil bacterial community for 105 days after the application of biosolids. AgNPs or CuONPs/g TS were first anaerobically digested with mixed primary and secondary sludge rather than adding pristine nanoparticles to biosolids directly. Both environmentally relevant (under the USEPA ceiling concentration limits) and high concentrations of AgNPs and CuONPs were tested. Soil tests included TOC, TN, TP, pH, cell viability and heterotrophic plate counts (HPC). Metagenomic data was generated by high-throughput sequencing of the 16S rRNA gene to explore bacterial populations and diversity. AgNPs and CuONPs at 2 and 30 mg NPs/g TS of sludge could impact soil health factors such as bacterial diversity, community structure, and the population of plant growth-promoting rhizobacteria (PGPR). The population of the highly abundant bacteria that have important physiological roles in soil decreased, while the less important bacteria for soil function we

Aptamer-Based Impedimetric Sensor for Bacterial Typing

The development of an aptamer-based impedimetric sensor for typing of bacteria (AIST-B) is presented. Highly specific DNA aptamers to <i>Salmonella enteritidis</i> were selected via Cell-SELEX technique. Twelve rounds of selection were performed; each comprises a positive selection step against <i>S. enteritidis</i> and a negative selection step against a mixture of related pathogens, including <i>Salmonella typhimurium</i>, <i>Escherichia coli</i>, <i>Staphylococcus aureus</i>, <i>Pseudomonas aeruginosa</i>, and <i>Citrobacter freundii</i>, to ensure the species-specificity of the selected aptamers. After sequencing of the pool showing the highest binding affinity to <i>S. enteritidis</i>, a DNA sequence of high affinity to the bacteria was integrated into an impedimetric sensor via self-assembly onto a gold nanoparticles-modified screen-printed carbon electrode (GNPs-SPCE). Remarkably, this aptasensor is highly selective and can successfully detect <i>S. enteritidis</i> down to 600 CFU mL^–1 (equivalent to 18 CFU in 30 μL assay volume) in 10 min and distinguish it from other Salmonella species, including <i>S. typhimurium</i> and <i>S. choleraesuis</i>. This report is envisaged to open a new venue for the aptamer-based typing of a variety of microorganisms using a rapid, economic, and label-free electrochemical platform

Aptamer-Based Viability Impedimetric Sensor for Bacteria

The development of an aptamer-based viability impedimetric sensor for bacteria (AptaVISens-B) is presented. Highly specific DNA aptamers to live <i>Salmonella typhimurium</i> were selected via the cell-systematic evolution of ligands by exponential enrichment (SELEX) technique. Twelve rounds of selection were performed; each comprises a positive selection step against viable <i>S. typhimurium</i> and a negative selection step against heat killed <i>S. typhimurium</i> and a mixture of related pathogens, including <i>Salmonella enteritidis</i>, <i>Escherichia coli</i>, <i>Staphylococcus aureus</i>, <i>Pseudomonas aeruginosa</i>, and <i>Citrobacter freundii</i> to ensure the species specificity of the selected aptamers. The DNA sequence showing the highest binding affinity to the bacteria was further integrated into an impedimetric sensor via self-assembly onto a gold nanoparticle-modified screen-printed carbon electrode (GNP-SPCE). Remarkably, this aptasensor is highly selective and can successfully detect <i>S. typhimurium</i> down to 600 CFU mL^–1 (equivalent to 18 live cells in 30 μL of assay volume) and distinguish it from other <i>Salmonella</i> species, including <i>S. enteritidis</i> and <i>S. choleraesuis</i>. This report is envisaged to open a new venue for the aptamer-based viability sensing of a variety of microorganisms, particularly viable but nonculturable (VBNC) bacteria, using a rapid, economic, and label-free electrochemical platform

Food and environmental parasitology in Canada:A network for the facilitation of collaborative research

Parasitic diseases are of considerable public health significance in Canada, particularly in rural and remote areas. Food- and water-borne parasites contribute significantly to the overall number of parasitic infections reported in Canada. While data on the incidence of some of these diseases are available, knowledge of the true burden of infection by the causative agents in Canadians is somewhat limited. A number of centers of expertise in Canada study various aspects of parasitology, but few formal societies or networks of parasitologists currently exist in Canada, and previously none focused specifically on food or environmental transmission. The recently established Food and Environmental Parasitology Network (FEPN) brings together Canadian researchers, regulators and public health officials with an active involvement in issues related to these increasingly important fields. The major objectives of the Network include identifying research gaps, facilitating discussion and collaborative research, developing standardized methods, generating data for risk assessments, policies, and guidelines, and providing expert advice and testing in support of outbreak investigations and surveillance studies. Issues considered by the FEPN include contaminated foods and infected food animals, potable and non-potable water, Northern and Aboriginal issues, zoonotic transmission, and epidemiology