Assessment of the Genetic Diversity of Sitophilus Zeamais in Countries of the Sahelo-Sudanian Zone (Senegal, Mali, Niger, Burkina Faso, Guinea Conakry)

Maize is exploited substantially in the countries of the semi-arid zone of West Africa [5] where it plays essential economic and social functions. But these functions are seriously threatened by heavy losses, caused mainly by the corn weevil (Sitophilus zeamais) (Motschusky, 1855). This article aims to assess the genetic diversity of the insect in 5 countries in the semi-arid zone. This evaluation will highlight the country (ies) where the susceptibility of S. zeamais to survive or disappear is high, because the genetic diversity of a population is positively linked to its adaptive potential [12]. Exploitation of 60 sequences of the cytochrome b gene from insects from countries in the area (Senegal, Mali, Niger, Burkina Faso, Guinea Conakry) has led to the conclusion that genetic diversity is high in Senegal, Guinea Conakry but especially in Burkina Faso and Niger. These countries would therefore favor the adaptability of the insect. However, it is very low in Mali. Thus this country would be unfavorable to the survival of S. zeamais

Study of variations in the broncho-arterial pedicles of the upper right lung lobe

Bronchial distribution and functional arterial vascularization of the upper lobe of the right lung are subject to many anatomical variations. The control of  these variations is essential for endoscopic and agiographic examinations. It also offers a better guarantee for safe and controlled surgery. In this  preliminary work, the exploitation of 15 heart-lung blocks treated by the injection corrosion method allowed us to study the general arrangement of the  broncho-arteries of the right upper lung lobe and their anatomical variations in the Senegalese population. Our results were as follows: the right upper  lobar bronchus was born on average at 1.25 cm from the tracheal bifurcation, with an average length of 1.13 cm. It ended with trifurcation into apical  (B1), dorsal (B2) and ventral (B3) segmental bronchi in 10 cases (66.66%); in 3 cases (20%), it ended with bifurcation into the dorsal segmental bronchus  and the apico-ventral trunk (B1+B3) (1 case), the apico-dorsal trunk (B1+B2) and the ventral segmental bronchus (B3), finally, in ventral and dorsal  segmentary bronchi giving each one an apical branch (1 case); in a last case, it ended by quadrifurcation, giving an external parabronche. The right upper  lobe was vascularized by 1 to 4 arteries, with eight modes of vascularization. It received more frequently two arteries. The anterior mediastinal  artery was the most common (100%). These results allowed us to discuss anatomical variations in the bronchial tree of the right upper lung lobe and the  pulmonary arterial distribution in that lobe. These variations must be taken into account during endoscopic examinations of imaging and surgery of  pulmonary excision, under penalty of accidents.&nbsp

Evolution phylogéographique et structure génétique des populations de Sitophilus zeamais (Coleoptera, Curculionidae), ravageur du maïs stocke en Afrique de l’Ouest

The maize weevil or Sitophilus zeamais (Motschulsky, 1855) is known because of its extraordinary potential for destroying stored grain; but little is known about its phylogeography and genetic structure in sub-saharan Africa. Therefore, the aim of this thesis is to define the phylogeography of West African populations and to estimate their gene flow using sequencing data (Cytochrome B and Cytochrome oxidase I) and genotyping. The analysis of the latter reveals the presence of 30 haplotypes (mtDNA) against 33 alleles (SSR). The majority haplotype represented about 43% of the total population and connected West Africa to Central Africa. Molecular analyzes indicated the presence of a genetic structure without a phylogeographic signal. This is the result of an asymmetric multidirectional flow (cross infestation) that would most likely be related to anthropogenic impacts through commercial activities. Populations also showed good viability potential reinforced by passive dispersal through the grain trade; and genetic diversity is more important in the north from which dispersal routes would have started since the Pleistocene period. The multivariate and Bayesian inferences suggested the existence of 4 to 5 main clusters that have separated after a bottleneck followed by a moderate population expansion since the Pleistocene period.This study provided new insights into the description of the genetic basis and differentiation of S. zeamais populations in the West African sub-region. It also helped to understand the processes that govern the biogenetic parameters of these populations. Therefore, it constitutes prospects for sustainable management of resources. Indeed, knowledge of evolutionary biology can influence parameters to reduce or even eliminate harmful effects of these pests.Le charançon du maïs ou Sitophilus zeamais (Motschulsky, 1855) est connu en raison de son extraordinaire potentiel de destruction des céréales stockées ; mais peu de données sont connues sur la phylogéographie et la structure génétique de ce ravageur en Afrique subsaharienne. En outre, l’objectif de cette thèse est de définir la phylogéographie des populations ouest-africaines et d’estimer leur flux génique à l’aide de données de séquençage (Cytochrome B et Cytochrome oxydase I) et de génotypage. L’analyse de ces dernières révèle la présence de 30 haplotypes (ADNmt) contre 33 allèles (SSR). L'haplotype majoritaire a représenté environ 43% de la population totale et a relié l'Afrique de l'Ouest à l'Afrique centrale. Les analyses moléculaires ont indiqué la présence d’une structure génétique sans signal phylogéographique. Ceci est la résultante d’un flux multidirectionnel asymétrique (infestation croisée) qui serait très probablement lié aux impacts anthropiques à travers les activités commerciales. Les populations ont aussi présenté un bon potentiel de viabilité renforcé par une dispersion passive à travers le commerce des grains ; et la diversité génétique est plus importante dans le Nord d’où partiraient les voies de dispersion depuis la période du Pléistocène. Les inférences multivariées et bayésiennes suggèrent l'existence de 4 à 5 principaux clusters génétiques qui se sont séparés après un goulot d'étranglement suivi d'une expansion démographique modérée depuis la période du pléistocène. Cette étude a fourni de nouveaux aperçus dans la description de la base et de la différenciation génétiques des populations de S. zeamais dans la sous-région ouest-africaine. Elle a aussi permis de comprendre les processus qui gouvernent les paramètres biogénétiques de ces populations. Par conséquent, il constitue un outil dans les perspectives de gestion durable des ressources agricoles. En effet, la connaissance de la biologie évolutive permet d’influencer sur différents paramètres pour diminuer, voire éliminer les effets néfastes de ces ravageurs