In the thyroid, iodotyrosine dehalogenase acts on the mono and diiodotyrosines released during the hydrolysis of thyroglobulin to liberate iodide, which can then reenter the hormone-producing pathways. It has been reported that the deiodination of iodotyrosines occurs predominantly in the microsomes and is mediated by NADPH. Recently, two cDNAs, 7401- and 7513-base pairs long that encode proteins with a conserved nitroreductase domain were published in GenBank as iodotyrosine dehalogenase 1 (DEHAL1) and iodotyrosine dehalogenase 1B (DEHAL1B), respectively. We report here our investigation of the localization and activity of one of these isoforms, DEHAL1. DEHAL1 mRNA is highly expressed in the thyroid, is up-regulated by cAMP, and encodes a transmembrane protein that efficiently catalyzes the NADPH-dependent deiodination of mono (L-MIT) and diiodotyrosine (L-DIT), with greater activity vs. L-MIT. Iodotyrosine deiodinase was active in HEK293 cells transfected by DEHAL1 cDNA, but not in CHO cells. A fraction of DEHAL1 protein is exposed to the cell surface, as indicated by biotinylation experiments. Immunohistochemistry studies showed that DEHAL1 proteins accumulate at the apical pole of thyrocytes. Taken together, these findings indicate that the deiodination reaction occurs at the apical pole of the thyrocyte and is involved in a rapid iodide recycling process at and/or close to the organification site.

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Our study aims to characterize Plant Growth Promoting Rhizobacteria (PGPR) isolated from maize roots in five agroecological zones of central and northern Benin. Sixty samples were collected at the rate of four samples per village and three villages per agroecological zone. Rhizobacteria strains were isolated from these samples and biochemically characterized. These strains were analyzed for some of their PGPR traits like ammonia production and hydrogen cyanide following conventional methods. Microbiological investigation of these samples has shown that maize rhizospheres in central and northern Benin contain a high diversity of microorganisms. A total of nine species of maize Plant Growth Promoting Rhizobacteria were identified. Those PGPR include five Bacillus species (B. polymyxa, B. pantothenticus, B. anthracis, B. thuringiensis, and B. circulans), three Pseudomonas species (P. cichorii, P. putida, and P. syringae), and Serratia marcescens. The microbial diversity does not depend on the soil types. The microbial density, generally high, varies according to both soil types and agroecological zones. All Serratia strains (100%) have produced ammonia, whereas 80% of Bacillus and 77.77% of Pseudomonas produced this metabolite. The hydrogen cyanide was produced by all isolates (100%) independent of their genus. These results suggest the possibility to use these rhizobacteria as biological fertilizers to increase maize production.

1083Cocos nucifera is a tropical coastal plant. The ethyl acetate fraction of its aqueous root extract stimulates erythropoiesis. This work aimed to evaluate the biological tolerance of this fraction. The extract fraction was administered to Wistar rats at a single dose of 2000 mg / kg body weight for Acute Oral Toxicity (OAT) or in daily doses of 200 mg / kg body weight for 28 days for Sub-Chronic Toxicity. (SCT), as recommended by the OECD. On day 0, then on day 14 for OAT and day 28 for SCT, the rats were weighed and their blood was collected for tests. The liver balance was assessed by measuring transaminases AST and ALT, kidney balance by uremia and creatinine level and immune status by blood leukocyte count. These analyzes were supplemented by the histology of the liver, kidneys and spleen, an immune organ. The weight of rats, the balance of liver, kidney and immunity as well as these organs histology were not affected by either acute oral or sub-chronic toxicity tests, suggesting a lack of toxicity in the extract fraction. The ethyl acetate fraction of the root water extract of Cocos nucifera did not reveal any acute or sub-chronic oral toxicity. This effect could be related to its richness in flavonoids that are antioxidants. The study of biological tolerance deserves to be continued by the chronic toxicity test and clinical trials.

Vegetative organs of Khaya senegalensis (Ders.) A. Juss. are widely used in African pharmacopoeia. A review of pharmacological studies, focused on this plant, was carried out, using the available scientific literature. Several studies have revealed its bioactive properties and therefore its medical efficacy. Aqueous and alcoholic extracts of the stem bark and leaves of this plant have shown efficient in the treatment of some bacterial infections. Their widely reported biochemical effects, such as α-amylase activity inhibition, decreasing in bowel motility and in some blood and serum enzyme (Aspartate transferase, Alanine transferase and Alkaline phosphatase) justify indications against diabetes, diarrhea and liver disorders. Antiparasitic properties directed against helminths and coccidian are also attributed to these herbal medicines. However, according to some results recorded in various studies, this plant has a high risk of toxicity in chronic treatment (several weeks). Histotoxic effects (in liver and kidney) resulting in increased of plasma total protein, blood urea and creatinine are reported.