Chemical composition and in vitro aryl hydrocarbon receptor-mediated activity of atmospheric particulate matter at an urban, agricultural and industrial site in North Africa (Bizerte, Tunisia).

As recognized risk factor to pose a health threat to humans and wildlife globally, atmospheric particulate matter (PM) were collected from a North African coastal city (Bizerte, Tunisia) for one year, and were characterized for their chemical compositions, including mercury (Hg), as well as organic contaminants (polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs)), organic carbon (OC) and organic nitrogen (ON), determined in a previous study. Then, we applied an in vitro reporter gene assay (DR-CALUX) to detect and quantify the dioxin-like activity of PM-associated organic contaminants. Results showed that average Hg concentration over the entire sampling period was found to be 13.

Diversity and bioactivities of nostocacean cyanobacteria isolated from paddy soil in Vietnam.

Nostocacean cyanobacteria are one of the important components of paddy fields due to their ability to fix atmospheric nitrogen and supply phytohormones for crop growth. In this study, 13 Nostoc strains isolated from paddy soils in Vietnam were classified using a polyphasic approach. The results showed a high diversity of the isolated strains that represented seven morphotypes corresponding to five genotypes, with 16S rRNA gene sequence similarity values ranging between 94.