Profil spermiologique des hommes infertiles au Mali

Infertility remains a major sociocultural problem in view of the fact that in Africa, in general, and in Mali, in particular, the main purpose of marriage remains procreation. The birth of a child is a source of joy and contributes to maintenance of a certain harmony in the home. In Africa, infertility is a dramatic problem that is difficult to bear for the couple. It is the leading cause of marital discord or divorce. It is considered to be due to fate, or a curse inflicted on the couple. For the woman, it represents a divine punishment, as it is usually the woman who is blamed for the problem male responsibility is only discovered during assessment of the couple’s infertility. Sperm count and sperm cytology are the basic examinations performed on semen. These examinations constitute key elements to evaluate the quality of semen. In Mali, the Cytogenetics and Reproduction Biology laboratory performs the greatest number of semen examinations in the country. The purpose of this study was to present the sperm profile of infertile men in Mali based on a 5-year retrospective study. Male infertility is a public health problem in Mali. The age-group most frequently affected is between 30 and 39 years. Primary sterility was the predominant form, observed in 70% of the subjects studied. Schistosomiasis plays a predominant role in the infectious history. The sperm count results show that cases of oligoasthenozoospermia and azoospermia represent 49.5% and 23.7% of the study population, respectively.     

Genetic diversity in Bambara groundnut (Vigna subterranea L.) germplasm revealed by RAPD markers.

Random amplified polymorphic DNA (RAPD) markers were used to assess genetic diversity in Bambara groundnut (Vigna subterranea L.) germplasm using 25 African accessions from the collection in the International Institute for Tropical Agriculture, Ibadan, Nigeria. Fifty random decamer primers were screened to assess their ability to detect polymorphism in bambara; 17 of them were selected for this study. Considerable genetic diversity was found among the V. subterranea accessions studied. The relationships among the 25 accessions were studied by cluster analysis. The dendrograms showed two main groups of accessions mainly along the lines of their geographic origin. It is concluded that RAPD can be used for germplasm classification in bambara groundnut and hence for improving this crop.     

Bat ectoparasites (Nycteribiidae,Streblidae, Siphonaptera,Heteroptera, Mesostigmata,Argasidae, and Ixodidae) from Algeria

Twenty two species of ectoparasites (Family Nycteribiidae: Nycteribia (Listropoda) schmidlii schmidlii, Nycteribia (Nycteribia) latreillii, Nycteribia (Nycteribia) pedicularia, Penicillidia (Penicillidia) dufourii, and Phthiridium biarticulatum; Family Streblidae: Brachytarsina (Brachytarsina) flavipennis and Raymondia huberi; Order Siphonaptera: Rhinolophopsylla unipectinata arabs, Nycteridopsylla longiceps, Araeopsylla gestroi, Ischnopsyllus intermedius, and Ischnopsyllus octactenus; Order Heteroptera: Cimex pipistrelli, Cimex lectularius, and Cacodmus vicinus; Class Arachnida: Order Mesostigmata: Spinturnix myoti and Eyndhovenia euryalis; Order Ixodida: Family Argasidae: Argas transgariepinus and Argas vespertilionis; Family Ixodidae: Hyalomma dromedarii, Ixodes ricinus, and Ixodes vespertilionis) were recovered from 19 bat species in Algeria. New host records for bats are recorded for the first time: N. schmidlii from Rh. clivosus and R. cystops; N. latreillii from Rh. blasii and P. gaisleri; R. huberi from Rh. clivosus; C. pipistrelli from E. isabellinus and H. savii; C. vicinus from E. isabellinus; S. myoti from P. gaisleri; E. euryalis from P. gaisleri and Rh. blasii; A. vespertilionis from P. gaisleri; I. ricinus from T. teniotis and Rh. hipposideros and H. dromedarii from P. kuhlii. Raymondia huberi is recorded for the first time from Algeria.     

Occurrence of nodulation in unexplored leguminous trees native to the West African tropical rainforest and inoculation response of native species useful in reforestation

Despite the abundance and diversity of timber tree legumes in the West African rainforest, their ability to form nitrogen-fixing nodules in symbiosis with rhizobia, and their response to rhizobial inoculation, remain poorly documented. In the first part of this study the occurrence of nodulation was determined in 156 leguminous species growing in six natural forest areas in Guinea, mostly mature trees. In the second part, an in situ experiment of rhizobial inoculation was performed on eight selected tree species belonging to three genera: Albizia, Erythrophleum and Millettia. Of the 97 plant species and 14 genera that had never been examined before this study, 31 species and four genera were reported to be nodulated. After 4 months of growing in a nursery and a further 11 months after transplantation of plants to the field, we observed a highly significant (P < 0.001) and positive effect of inoculation with Bradyrhizobium sp. strains on the growth of the eight tree species tested. The importance of determining the nodulation ability of unexplored local trees and subsequently using this information for inoculation in reforestation programmes was demonstrated.     

Origin and diversification of the human parasite Schistosoma mansoni

Schistosoma mansoni is the most widespread of the human-infecting schistosomes, present in 54 countries, predominantly in Africa, but also in Madagascar, the Arabian Peninsula, and the Neotropics. Adult-stage parasites that infect humans are also occasionally recovered from baboons, rodents, and other mammals. Larval stages of the parasite are dependent upon certain species of freshwater snails in the genus Biomphalaria, which largely determine the parasite's geographical range. How S. mansoni genetic diversity is distributed geographically and among isolates using different hosts has never been examined with DNA sequence data. Here we describe the global phylogeography of S. mansoni using more than 2500 bp of mitochondrial DNA (mtDNA) from 143 parasites collected in 53 geographically widespread localities. Considerable within-species mtDNA diversity was found, with 85 unique haplotypes grouping into five distinct lineages. Geographical separation, and not host use, appears to be the most important factor in the diversification of the parasite. East African specimens showed a remarkable amount of variation, comprising three clades and basal members of a fourth, strongly suggesting an East African origin for the parasite 0.30-0.43 million years ago, a time frame that follows the arrival of its snail host. Less but still substantial variation was found in the rest of Africa. A recent colonization of the New World is supported by finding only seven closely related New World haplotypes which have West African affinities. All Brazilian isolates have nearly identical mtDNA haplotypes, suggesting a founder effect from the establishment and spread of the parasite in this large country.     

Rhizobial Populations in Soils from Natural Acacia senegal and Acacia nilotica Forests in Mauritania and the Senegal River Valley

Eighty-two strains of rhizobia were isolated from soils taken from several sites in Mauritania and Senegal. These soil samples were collected from natural stands of Acacia nilotica and Acacia senegal. The soils from Mauritania were less rich in native rhizobia than the soils from Senegal. The strains were characterized using polymerase chain reaction–restriction fragment length polymorphism and by sequencing the rDNA 16S–23S intergenic spacer region (IGS). They were sorted into seven IGS groups. These groups were not associated with the geographical origin of the strains or with the host-plant species at the site where the soils were collected. Most of the strains were in three of the IGS groups (I, IV, and V). One representative strain from each IGS group was sequenced and showed that the strains were from the genus Mesorhizobium. IGS groups I, IV, and VI were close to the species M. plurifarium (AF34563), IGS groups IIand III were close to the species Mesorhizobium sp. (AF510360), IGS group V was close to the species Mesorhizobium sp. (AF510366), and IGS group VII was close to Mesorhizobium sp. (AF510346).     

Anesthetic preconditioning: triggering role of reactive oxygen and nitrogen species in isolated hearts

We postulated that anesthetic preconditioning (APC) is triggered by reactive oxygen/nitrogen species (ROS/RNS). We used the isolated guinea pig heart perfused with L-tyrosine, which reacts with ROS and RNS to form strong oxidants, principally peroxynitrite (ONOO(-)), and then forms fluorescent dityrosine. ROS scavengers superoxide dismutase, catalase, and glutathione (SCG) and NO. synthesis inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME) were given 5 min before and after sevoflurane preconditioning stimuli. Drugs were washed out before 30 min of ischemia and 120 min of reperfusion. Groups were control (nontreated ischemia control), APC (two, 2-min periods of perfusion with 0.32 +/- 0.02 mM of sevoflurane; separated by a 6-min period of perfusion without sevoflurane), SCG, APC + SCG, L-NAME, and APC + L-NAME. Effluent dityrosine at 1 min reperfusion was 56 +/- 6 (SE), 15 +/- 5, 40 +/- 5(++), 39 +/- 4(++), 35 +/- 4(++) , and 33 +/- 5(++) units ((++)P< 0.05 vs. APC), respectively; left ventricular pressure (%baseline) at 60 min of reperfusion was 30 +/- 5(++), 60 +/- 4, 35 +/- 5(++), 37 +/- 5(++), 44 +/- 4, and 47 +/- 4; and infarct size (%total heart weight) was 50 +/- 5(++), 19 +/- 2, 48 +/- 3(++), 46 +/- 4(++), 42 +/- 4(++), and 45 +/- 2(++). Thus APC is initiated by ROS as shown by improved function, reduced infarct size, and reduced dityrosine on reperfusion; protective and ROS/RNS-reducing effect of APC were attenuated when bracketed by ROS scavengers or NO* inhibition.     

Response of native soil microbial functions to the controlled mycorrhization of an exotic tree legume, <Emphasis Type="Italic">Acacia holosericea</Emphasis> in a Sahelian ecosystem

Fifty years of overexploitation have disturbed most forests within Sahelian areas. Exotic fast growing trees (i.e., Australian Acacia species) have subsequently been introduced for soil improvement and fuelwood production purposes. Additionally, rhizobial or mycorrhizal symbioses have sometimes been favored by means of controlled inoculations to increase the performance of these exotic trees in such arid and semiarid zones. Large-scale anthropogenic introduction of exotic plants could also threaten the native biodiversity and ecosystem resilience. We carried out an experimental reforestation in Burkina Faso in order to study the effects of Acacia holosericea mycorrhizal inoculation on the soil nutrient content, microbial soil functionalities and mycorrhizal soil potential. Treatments consisted of uninoculated A. holosericea, preplanting fertilizer application and arbuscular mycorrhizal inoculation with Glomus intraradices. Our results showed that (i) arbuscular mycorrhizal (AM) inoculation and prefertilizer application significantly improved A. holosericea growth after 4 years of plantation and (ii) the introduction of A. holosericea trees significantly modified soil microbial functions. The results clearly showed that the use of exotic tree legume species should be directly responsible for important changes in soil microbiota with great disturbances in essential functions driven by microbial communities (e.g., catabolic diversity and C cycling, phosphatase activity and P availability). They also highlighted the importance of AM symbiosis in the functioning of soils and forest plantation performances. The AM effect on soil functions was significantly correlated with the enhanced mycorrhizal soil potential recorded in the AM inoculation treatment.