Changes in arbuscular mycorrhizal fungal communities, mycorrhizal soil infectivity, and phosphorus availability under Chromolaena odorata (Asteraceae) invasions in a West-African forest-savanna ecotone.

Substantial areas of agricultural lands in Sub-Saharan Africa have been invaded by Chromolaena odorata (Asteraceae), but the consequences for arbuscular mycorrhiza fungi (AMF) remains poorly understood. This study explores changes in diverse AMF community attributes and soil available phosphorus following C. odorata invasion in forest and savanna fragments in Côte d'Ivoire (West Africa). Invaded-forest (COF) and savanna (COS) sites were compared to adjacent natural forest (FOR) and savanna (SAV) fragments, respectively. Physico-chemical variables and AMF spore density parameters were determined for soil samples from 0-20 cm depth. An 18S ribosomal RNA metabarcoding analysis of AMF communities was conducted. In addition, cowpea (Vigna unguiculata) was grown on soils collected from these sites under greenhouse conditions for determination of soil mycorrhizal infectivity. Noticeable changes in the composition of AMF communities in C. odorata relative to nearby forest and savanna non-invaded sites were observed. AMF-specific richness in COS (47 species) was lower than that in SAV (57 species) while it was higher in COF (68 species) than in FOR (63 species). COF and COS differed in AMF specific composition (Dissimilarity index = 50.6%). Chromolaena odorata invasions resulted in increased relative abundances of the genera Claroideoglomus and Glomus in COF, a decreased relative abundance of Paraglomus in COS and decreased relative abundances of Ambispora in both COF and COS. Total and healthy spore densities, cowpea root colonization intensity and soil available P were all higher in invaded sites than in natural ecosystems. Remarkably, although these values were different in FOR and SAV, they turned out to be similar in COF and COS (4.6 and 4.2 total spores g-1 soil, 2.3 and 2.0 healthy spores g-1 soil, and 52.6 and 51.6% root colonization, respectively) suggesting a C. odorata-specific effect. These findings indicate that soil mycorrhizal potential and phosphorus availability have improved following C. odorata invasion.

Use of couplers for vascular anastomoses in 601 free flaps for reconstruction of defects of the head and neck: technique and two-year retrospective clinical study.

We describe our experience with the use of 854 couplers for venous or arterial anastomoses, or both, in 601 free flaps for reconstruction of defects of the head and neck. We reviewed 601 patients who had had free flaps (with the microvascular anastomoses being made with couplers in 519) between July 2013 and December 2015. Personal details, and clinical data including the site of the defect, the tumour excised, the types of flaps, the size of the couplers, the method of anastomosis (venous or arterial) in which the coupler was used, and postoperative complications were recorded. There were 417 men (69%) and 184 women (31%), mean (range) age 53 (13-91) years. Four types of flaps were used: anterolateral thigh flap (n=232), radial forearm flap (n=223), fibula free flap (n=78), and iliac crest flap (n=68). The sizes of couplers ranged from 1-4mm, most being 2mm (n=158), followed by 1.5mm (n=122). The recipient vessels used included a single vein (n=348), two veins (n=406), and both vein and artery (n=100). The overall success rate was 99%, and eight patients required resuture, which was successful in each case. This retrospective study shows that a coupler is easy to use, and is a reliable and time-saving technique for microvascular anastomosis. However, the disadvantage is the cost of the instrument, which in less developed countries will limit its use.

Myosin XI is associated with fitness and adaptation to aridity in wild pearl millet.

Phenotypic changes in plants can be observed along many environmental gradients and are determined by both environmental and genetic factors. The identification of alleles associated with phenotypic variations is a rapidly developing area of research. We studied the genetic basis of phenotypic variations in 11 populations of wild pearl millet (Pennisetum glaucum) on two North-South aridity gradients, one in Niger and one in Mali. Most of the 11 phenotypic traits assessed in a common garden experiment varied between the populations studied. Moreover, the size of the inflorescence, the number of flowers and aboveground dry mass co-varied positively with a decrease in rainfall. To decipher the genetic basis of these phenotypes, we used an association mapping strategy with a mixed model. We found two SNPs on the same myosin XI contig significantly associated with variations in the average number of flowers. Both the allele frequency of the two SNPs and the average number of flowers co-varied with the rainfall gradient on the two gradients. Interestingly, this gene was also a target of selection during domestication. The Myosin XI gene is thus a good candidate for fitness-related adaptation in wild populations.

Isolation and characterization of microsatellite markers for Acacia senegal (L.) Willd., a multipurpose arid and semi-arid tree.

Acacia senegal is a multipurpose African tree that improves the soil fertility of degraded areas. The species is exploited mainly for gum arabic, but it also supplies fuel wood and fodder for animals. Despite its wide distribution in Africa, no microsatellite markers have yet been characterized for this species. In this study, we characterized 11 polymorphic microsatellite loci specifically designed for A. senegal and analysed 247 individuals from three populations from Niger. On average, 10.9 alleles per locus were detected and expected heterozygosity ranged from 0.160 to 0.794, showing the ability of the markers to detect genetic diversity in this species.

Les cancers du sein masculin à Niamey

Moins frequent que chez la femme; le cancer du sein existe aussi chez l'homme. A partir d'une serie hospitaliere a Niamey au Niger; nous avons entrepris une etude retrospective afin d'en analyser les particularites epidemiologiques cliniques et therapeutiques. Durant la periode d'etudes (1992-2006); nous avons collige 18 cas microscopiquement confirmes. La majorite des malades etaient d'origine rurale. Ils se sont presentes a des stades avances : T3 et T4. Toutes les malades ont ete operees; seules 4 parmi elles ont eu un traitement complementaire adjuvant. Le carcinome canalaire infiltrant a ete le type histologique le plus frequent (55;5). L'evolution n'a pu etre evaluer car tous les malades etaient perdues de vue 6 mois apres l'acte operatoire