The Abundance and Diversity of Legume-Nodulating Rhizobia in 28-Year-Old Plantations of Tropical, Subtropical, and Exotic Tree Species: a Case Study from the Forest Reserve of Bandia, Senegal

Several fast-growing and multipurpose tree species have been widely used in West Africa to both reverse the tendency of land degradation and restore soil productivity. Although beneficial effects have been reported on soil stabilization, there still remains a lack of information about their impact on soil microorganisms. Our investigation has been carried out in exotic and native tree plantations of 28 years and aimed to survey and compare the abundance and genetic diversity of natural legume-nodulating rhizobia (LNR). The study of LNR is supported by the phylogenetic analysis which clustered the isolates into three genera: Bradyrhizobium, Mesorhizobium, and Sinorhizobium. The results showed close positive correlations between the sizes of LNR populations estimated both in the dry and rainy seasons and the presence of legume tree hosts. There were significant increases in Rhizobium spp. population densities in response to planting with Acacia spp., and high genetic diversities and richness of genotypes were fittest in these tree plantations. This suggests that enrichment of soil Rhizobium spp. populations is host specific. The results indicated also that species of genera Mesorhizobium and Sinorhizobium were lacking in plantations of non-host species. By contrast, there was a widespread distribution of Bradyrhizobium spp. strains across the tree plantations, with no evident specialization in regard to plantation type. Finally, the study provides information about the LNR communities associated with a range of old tree plantations and some aspects of their relationships to soil factors, which may facilitate the management of man-made forest systems that target ecosystem rehabilitation and preservation of soil biota.     

Prediction of GTP interacting residues,dipeptides and tripeptides in a protein from its evolutionary information

Background  

Guanosine triphosphate (GTP)-binding proteins play an important role in regulation of G-protein. Thus prediction of GTP interacting residues in a protein is one of the major challenges in the field of the computational biology. In this study, an attempt has been made to develop a computational method for predicting GTP interacting residues in a protein with high accuracy (Acc), precision (Prec) and recall (Rc).     

Apport de la scintigraphie osseuse dans le diagnostic des arthrites inflammatoires rares : à propos d’un cas de syndrome de Sapho à l’hôpital général de Grand Yoff

The SAPHO syndrome is suspected in a 47 years old Senegalese female patient with a swelling of medial quarter of the right clavicle, and a history of palmar pustulosis. The general state of health is preserved, biology shows a nonspecific inflammatory syndrome (elevated erythrocyte rate and C reactive protein level) and an absence of leukocytosis. Histopathological examination found a polymorphic inflammatory granuloma with mononuclear cells and giant cells. The standard radiographs and CT scans did not disclose any lesion while the bone scan displayed a “bull's horn” image of increased uptake on the right sterno-clavicular region suggestive of SAPHO syndrome. The frequent delay in diagnosis, usually related to ignorance of the syndrome and the fear of a bone tumour, is a major source of antibiotic abuse and/or biopsies, invasive or harmful for patients. Bone scintigraphy has a role to play in guiding the diagnosis when it discovers focal increased uptake on clavicle and sternum. May moreover, bone scintigraphy be useful to review and assess the distribution of lesions and their follow-up.