Effet du passage par le tractus digestif des ruminants domestiques sur la germination des graines de légumineuses ligneuses des zones tropicales sèches

La survie et la germination des graines de sept espèces de légumineuses ligneuses (A. nilotica adansonii, A. raddiana, A. senegal, A. seyal, B. rufescens, F. albida et P. juliflora) ont été étudiées après ingestion et excrétion par des bovins, des ovins et des caprins. Cette étude montre que : - les graines dures restent intactes et conservent leur viabilité après excrétion par les ruminants domestiques alors que les graines aux téguments perméables sont détruites; - les bovins excrètent significativement plus de graines intactes que les petits ruminants. Cette différence semble liée essentiellement à l'activité masticatoire plus importante chez les ovins et les caprins; - la germination des graines dures n'est pas améliorée après passage dans le tractus digestif des ruminants. Au total, l'ingestion par les ruminants domestiques ne peut être considérée comme un facteur favorisant la levée de dormance des graines dures, mais seulement comme un moyen de dissémination de graines intactes. (Résumé d'auteur

Contrasting deficits on executive functions between ADHD and reading disabled children

BACKGROUND. The object of this study was to analyze the executive functioning of children with attention deficit hyperactivity disorder (ADHD) or reading disability (RD) independent of their non-executive deficits. METHODS: Three carefully diagnosed groups of children, aged between 7 and 12 years (35 ADHD, 22 RD and 30 typically developing children), were tested on a wide range of tasks related to five major domains of executive functioning (EF): inhibition, visual working memory, planning, cognitive flexibility, and verbal fluency. Additional tasks were selected for each domain to control for non-executive processing. RESULTS: ADHD children were impaired on interference control, but not on prepotent and ongoing response suppression. ADHD showed deficits on visual working memory, planning, cognitive flexibility and phonetic fluency. RD children were impaired on phonetic fluency. The only EF measure that differentiated ADHD from RD was planning. CONCLUSIONS: The present sample of ADHD children showed several EF deficits, whereas RD children were almost spared executive dysfunction, but exhibited deficits in phonetic fluency

Spatial Analysis of Land Use by Cattle Herds in a Village of the Sudanese Zone in Senegal. Application for Grazing System Improvement

Spatial analysis of land use by cattle herds in the sub-humid area of Senegal is conducted through the utilisation of a Geographic Information System. This tool allows us to establish relationships between spatial practices, ruminant nutrition and performances. It gives leads to proposals for the improvement of the extensive ruminant feeding system

P27Kip1, regulated by glycogen synthase kinase-3β, results in HMBA-induced differentiation of human gastric cancer cells

<p>Abstract</p> <p>Background</p> <p>Gastric cancer is the second most common cause of global cancer-related mortality. Although dedifferentiation predicts poor prognosis in gastric cancer, the molecular mechanism underlying dedifferentiation, which could provide fundamental insights into tumor development and progression, has yet to be elucidated. Furthermore, the molecular mechanism underlying the effects of hexamethylene bisacetamide (HMBA), a recently discovered differentiation inducer, requires investigation and there are no reported studies concerning the effect of HMBA on gastric cancer.</p> <p>Methods</p> <p>Based on the results of FACS analysis, the levels of proteins involved in the cell cycle or apoptosis were determined using western blotting after single treatments and sequential combinations of HMBA and LiCl. GSK-3β and proton pump were investigated by western blotting after up-regulating Akt expression by Ad-Akt infection. To investigate the effects of HMBA on protein localization and the activities of GSK-3β, CDK2 and CDK4, kinase assays, immunoprecipitation and western blotting were performed. In addition, northern blotting and RNase protection assays were carried out to determine the functional concentration of HMBA.</p> <p>Results</p> <p>HMBA increased p27Kip1 expression and induced cell cycle arrest associated with gastric epithelial cell differentiation. In addition, treating gastric-derived cells with HMBA induced G0/G1 arrest and up-regulation of the proton pump, a marker of gastric cancer differentiation. Moreover, treatment with HMBA increased the expression and activity of GSK-3β in the nucleus but not the cytosol. HMBA decreased CDK2 activity and induced p27Kip1 expression, which could be rescued by inhibition of GSK-3β. Furthermore, HMBA increased p27Kip1 binding to CDK2, and this was abolished by GSK-3β inhibition.</p> <p>Conclusions</p> <p>The results presented herein suggest that GSK-3β functions by regulating p27Kip1 assembly with CDK2, thereby playing a critical role in G0/G1 arrest associated with HMBA-induced gastric epithelial cell differentiation.</p

Acacia senegal, arbre fourrager sahélien ?

National audienceThe value of A. senegal as a fodder plant was analysed against criteria for food value, productiveness and palatability. Among Sahelian fodder trees, the leaves of A. senegal, with their high nutritional value, high content of digestible crude protein and low tannin content, provide fodder of excellent quality. It is less productive in terms of fodder than other species investigated, whether in terms of total biomass or seasonal availability, but its value lies in the fact that it produces its first green leaves very soon after the end of the dry season, when fodder is generally very scarce in the Sahel. Compared to other woody species, A. senegal fodder is particularly attractive to domestic ruminants, except cattle. However, it is only eaten around the end of the dry season when other fodder is scarce. A further point is that animals eating the pods will entirely destroy the seeds, which can raise problems for the management of local A. senegal stands. Even though the species is not the most productive, its fodder value is a major advantage and should be taken into account with other criteria in reafforestation programmes for gum trees, especially in terms of population management and production.Se estudió el posible aprovecha- miento forrajero de A. senegal según criterios de valor alimenticio, produc- tividad forrajera y palatabilidad. Dentro de los árboles forrajeros sahe- lianos, las hojas de A. senegal tienen un valor alimenticio muy bueno con un alto contenido de nitrógeno diges- tible y un bajo contenido de taninos, car acterísticas que lo convierten en un forraje de primera calidad. Sin embar go, esta especie tiene una pr o - ductividad forrajera reducida, inferior a la de las demás especies estudia- das, tanto en términos de biomasa total producida anualmente como de disponibilidad estacional. A pesar de esto, tiene la interesante cualidad de producir nuevas hojas precoces desde el final de la temporada seca, período habitual de déficit forr ajero en el Sahel. Compar ado con las otr as especies leñosas, este forr aje es muy apr eciado por los rumiantes domésti - cos, excluyendo a los bovinos. El con- sumo, no obstante, se limita al final de la temporada seca, en período de déficit forr ajer o . P or otra parte, el consumo de las vainas provoca una destrucción total de las semillas, lo que puede r eper cutir en el manejo de los rodales. Aunque A. senegal no tiene la mejor productividad, su valor forrajero constituye una ventaja sobresaliente. Este criterio debe tenerse en cuenta en los programas de r eplantación de gomer os, espe - cialmente en cuanto al manejo y pro- ducción de los rodales.L'intérêt fourrager d'A. senegal a été étudié pour des critères de valeur alimentaire, productivité fourragère et d'appétibilité. Parmi les arbres fourragers sahéliens, les feuilles d'A. senegal ont une très bonne valeur alimentaire avec une teneur élevée en azote digestible et une faible teneur en tannins, ce qui en fait un fourrage de toute première qualité. Cependant, cette essence a une productivité fourragère réduite, plus faible que celle des autres espèces étudiées, tant en termes de biomasse totale produite annuellement que de disponibilité saisonnière. Toutefois, elle présente l'intérêt de produire de nouvelles feuilles précoces dès la fin de saison sèche, période habituelle de déficit fourrager au Sahel. Comparé aux autres espèces ligneuses, ce fourrage est très appété par les ruminants domestiques, à l'exclusion des bovins. La consommation est, toutefois, limitée à la fin de la saison sèche, en période de déficit fourrager. Par ailleurs, la consommation des gousses conduit à une destruction totale des graines, ce qui peut avoir des conséquences pour la gestion des peuplements. Même si A. senegal n'a pas une productivité élevée, sa valeur fourragère représente néanmoins un atout majeur. Ce critère doit être pris en compte dans les programmes de replantation des gommiers, notamment en termes de gestion et production des peuplements

PKA and CaMKII mediate PI3K activation in bovine sperm by inhibition of the PKC/PP1 cascade

To enable fertilization, spermatozoa must undergo several biochemical processes in the female reproductive tract, collectively called capacitation. These processes involve protein kinase A (PKA)-dependent protein tyrosine phosphorylation including phosphatidylinositol-3-kinase (PI3K). It is not known how PKA, a serine/threonine (S/T) kinase, mediates tyrosine phosphorylation of proteins. We recently showed that inhibition of S/T phosphatase 1 (PP1) causes a significant increase in phospho-PI3K. In this study, we propose a mechanism by which PKA and PP1 mediate an increase in PI3K tyrosine phosphorylation and implicate calmodulin-dependent kinase II (CaMKII) in this process. Inhibition of sperm PP1 or PKC, stimulated CaMKII phosphorylation/activation, and inhibition of PKC enhanced PP1 phosphorylation/inactivation. Inhibition of CaMKII, using KN-93, caused significant reduction in phospho-PP1, indicating its activation. Moreover, KN-93 prevented the dephosphorylation/inactivation of PKC. We therefore suggest that CaMKII inhibits PKC, leading to PP1 inhibition and the reciprocal auto-activation of CaMKII. Thus, CaMKII can regulate its own activation by inhibiting the PKC/PP1 cascade. Inhibition of Src family kinases (SFK) caused significant inhibition of CaMKII and PP1 phosphorylation, suggesting that SFK activity results in PP1 inhibition and CaMKII activation. Activation of sperm PKA by 8Br-cAMP revealed an increase in phospho-CaMKII, which was inhibited by PKA inhibitor. Tyrosine phosphorylation of PI3K was stimulated by 8Br-cAMP and by PKC or PP1 inhibition and was abrogated by CaMKII inhibition. Furthermore, phosphorylation/activation of the tyrosine kinase Pyk2 was enhanced by PP1 inhibition, and this activation is blocked by CaMKII inhibition. Thus, PKA activates Src, which inhibits PP1, leading to CaMKII and Pyk2 activation, resulting in PI3K tyrosine phosphorylation/activation.</jats:p

Spatial analysis of land use by cattle herds in a village of the Sudanese zone in Senegal. Application for grazing system improvement

Spatial analysis of land use by cattle herds in the sub-humid area of Senegal is conducted through the utilisation of a geographic information system. This tool allows us to establish relationships between spatial practices, ruminant nutrition and performances. It gives leads to proposals for the improvement of the extensive ruminant feeding system. (Résumé d'auteur