Petits Barbus (Pisces, Cyprinidae) du Rwanda

L'examen morphologique complété par des observations sur le terrain sur la coloration de plusieurs séries de petits #Barbus provenant des lacs et rivières du Rwanda, ont permis d'y distinguer au moins huit espèces : #B. kerstenii Peters, 1868, #B. neeumayeri Fisher, 1884, #B. nyanzae Whitehead, 1960, #B. cercops Whitehead, 1960, #B. lineomaculatus Boulenger, 1903, #B. paludinosus Peters, 1852, #B. pellegrini Poll, 1939 et #B. apleurogramma$ Boulenger, 1911. Ces espèces sont redécrites; pour chaque espèce la répartition géographique au Rwanda et en Afrique a été précisée et une clé de détermination pour ce groupe est proposée. (Résumé d'auteur

Révision de quelques Barbus à trois taches (Pisces, Cyprinidae) d'Afrique de l'Ouest, avec la description de trois nouvelles espèces : B. tiekoroi sp. n., B. traorei sp. n. et B. trispiloides sp. n.

Les #Barbus d'Afrique de l'Ouest caractérisés par une livrée à trois taches bien individualisées sur les flancs, ont fait l'objet d'une révision systématique. Trois espèces nouvelles ont été décrites : #B. tiekoroi sp. n (Guinée), #B. traorei sp. n. (Côte d'Ivoire) et #B. trispiloides sp. n. (Liberia). Une clé de détermination est proposée et la distribution géographique des différentes espèces est précisée. (Résumé d'auteur

Description de Barbus parawaldroni sp.n. (Pisces, Cyprinidae) d'Afrique Occidentale

Une nouvelle espèce de grand #Barbus, #Barbus parawaldroni sp. n. est décrite d'Afrique de l'Ouest. Elle présente des affinités avec #B. waldroni$ dont elle se différencie essentiellement par la faible ossification du dernier rayon simple de la dorsale. (Résumé d'auteur

Chemoorganotrophic Bioleaching of Olivine for Nickel Recovery

Bioleaching of olivine, a natural nickel-containing magnesium-iron-silicate, was conducted by applying chemoorganotrophic bacteria and fungi. The tested fungus, Aspergillus niger, leached substantially more nickel from olivine than the tested bacterium, Paenibacillus mucilaginosus. Aspergillus niger also outperformed two other fungal species: Humicola grisae and Penicillium chrysogenum. Contrary to traditional acid leaching, the microorganisms leached nickel preferentially over magnesium and iron. An average selectivity factor of 2.2 was achieved for nickel compared to iron. The impact of ultrasonic conditioning on bioleaching was also tested, and it was found to substantially increase nickel extraction by A. niger. This is credited to an enhancement in the fungal growth rate, to the promotion of particle degradation, and to the detachment of the stagnant biofilm around the particles. Furthermore, ultrasonic conditioning enhanced the selectivity of A. niger for nickel over iron to a value of 3.5. Pre-carbonating the olivine mineral, to enhance mineral liberation and change metal speciation, was also attempted, but did not result in improvement as a consequence of the mild pH of chemoorganotrophic bioleaching

Nickel Extraction from Olivine: Effect of Carbonation Pre-Treatment

In this work, we explore a novel mineral processing approach using carbon dioxide to promote mineral alterations that lead to improved extractability of nickel from olivine ((Mg,Fe)2SiO4). The precept is that by altering the morphology and the mineralogy of the ore via mineral carbonation, the comminution requirements and the acid consumption during hydrometallurgical processing can be reduced. Furthermore, carbonation pre-treatment can lead to mineral liberation and concentration of metals in physically separable phases. In a first processing step, olivine is fully carbonated at high CO2 partial pressures (35 bar) and optimal temperature (200 °C) with the addition of pH buffering agents. This leads to a powdery product containing high carbonate content. The main products of the carbonation reaction include quasi-amorphous colloidal silica, chromium-rich metallic particles, and ferro-magnesite ((Mg1−x,Fex)CO3). Carbonated olivine was subsequently leached using an array of inorganic and organic acids to test their leaching efficiency. Compared to leaching from untreated olivine, the percentage of nickel extracted from carbonated olivine by acid leaching was significantly increased. It is anticipated that the mineral carbonation pre-treatment approach may also be applicable to other ultrabasic and lateritic ores

Manuel pratique d'identification des poissons du lac d'Ayamé (Rivière Bia, Côte d'Ivoire)

A taxonomic assessment of fish species was carried out in the Lake Ayamé as a preliminary evaluation within the framework of a project to appraise the biodiversity changes occurred in fish after the construction of a dam at Ayamé in 1959

Macrophage miR-210 induction and metabolic reprogramming in response to pathogen interaction boost life-threatening inflammation

Unbalanced immune responses to pathogens can be life-threatening although the underlying regulatory mechanisms remain unknown. Here, we show a hypoxia-inducible factor 1α–dependent microRNA (miR)–210 up-regulation in monocytes and macrophages upon pathogen interaction. MiR-210 knockout in the hematopoietic lineage or in monocytes/macrophages mitigated the symptoms of endotoxemia, bacteremia, sepsis, and parasitosis, limiting the cytokine storm, organ damage/dysfunction, pathogen spreading, and lethality. Similarly, pharmacologic miR-210 inhibition improved the survival of septic mice. Mechanistically, miR-210 induction in activated macrophages supported a switch toward a proinflammatory state by lessening mitochondria respiration in favor of glycolysis, partly achieved by downmodulating the iron-sulfur cluster assembly enzyme ISCU. In humans, augmented miR-210 levels in circulating monocytes correlated with the incidence of sepsis, while serum levels of monocyte/macrophage-derived miR-210 were associated with sepsis mortality. Together, our data identify miR-210 as a fine-tuning regulator of macrophage metabolism and inflammatory responses, suggesting miR-210–based therapeutic and diagnostic strategies