Etude écologique du Parc National de Mozogo-Gokoro (Cameroun): prospections préliminaires de la flore ligneuse et du sol pour sa conservation et son aménagement

La conservation et la gestion rationnelle des aires protégées requièrent des études préalables de caractérisations écologique et floristique. Dans cette optique, il a été envisagé des prospections de base de la flore ligneuse et du sol pour l’aménagement du Parc National de Mozogo-Gokoro (PNMG), situé en zone sahélo-soudanienne, région de l’Extrême-Nord au Cameroun. Les données obtenues décrivent un sol favorable à la production végétale : texture sablo-limoneuse, activités biologiques présentes et absence d’érosion. La végétation présente une physionomie de forêt sèche claire à dense. La diversité compositionnelle montre sa grande richesse floristique, avec 62 espèces de ligneux identifiées. L’indice de Shannon est évalué à 3,75 bits avec une équitabilité de 0,84. Dans sa structure, il peut être relevé une densité très élevée (2972 tiges/hectare) et la forte représentativité des moyennes et hautes tiges, preuves de sa grande préservation. Les types phytogéographiques rapprochent la végétation des zones soudaniennes à guinéennes. Ces caractéristiques peuvent lui conférer le statut d’écosystème de référence montrant un transfert d’espèces des zones guinéennes et soudaniennes au sahélien, malgré les menaces anthropiques notées. Ces spécificités floristiques peuvent s’expliquer par les mesures de conservation appliquées, la pédologie et la topographie (bas-fond, piémont). L’obtention d’attributs vitaux, de façon plus approfondie, pourrait confirmer ces analyses et contribuer plus significativement à son processus d’aménagement.Mots clés : Pré-inventaire, diversité compositionnelle, structure, écosystème de référence, menaces anthropiques, aire protégé

Global Analysis of Predicted G Protein-Coupled Receptor Genes in the Filamentous Fungus, Neurospora crassa.

G protein-coupled receptors (GPCRs) regulate facets of growth, development, and environmental sensing in eukaryotes, including filamentous fungi. The largest predicted GPCR class in these organisms is the Pth11-related, with members similar to a protein required for disease in the plant pathogen Magnaporthe oryzae. However, the Pth11-related class has not been functionally studied in any filamentous fungal species. Here, we analyze phenotypes in available mutants for 36 GPCR genes, including 20 Pth11-related, in the model filamentous fungus Neurospora crassa. We also investigate patterns of gene expression for all 43 predicted GPCR genes in available datasets. A total of 17 mutants (47%) possessed at least one growth or developmental phenotype. We identified 18 mutants (56%) with chemical sensitivity or nutritional phenotypes (11 uniquely), bringing the total number of mutants with at least one defect to 28 (78%), including 15 mutants (75%) in the Pth11-related class. Gene expression trends for GPCR genes correlated with the phenotypes observed for many mutants and also suggested overlapping functions for several groups of co-transcribed genes. Several members of the Pth11-related class have phenotypes and/or are differentially expressed on cellulose, suggesting a possible role for this gene family in plant cell wall sensing or utilization

Global Analysis of Predicted G Protein−Coupled Receptor Genes in the Filamentous Fungus, Neurospora crassa

G protein−coupled receptors (GPCRs) regulate facets of growth, development, and environmental sensing in eukaryotes, including filamentous fungi. The largest predicted GPCR class in these organisms is the Pth11-related, with members similar to a protein required for disease in the plant pathogen Magnaporthe oryzae. However, the Pth11-related class has not been functionally studied in any filamentous fungal species. Here, we analyze phenotypes in available mutants for 36 GPCR genes, including 20 Pth11-related, in the model filamentous fungus Neurospora crassa. We also investigate patterns of gene expression for all 43 predicted GPCR genes in available datasets. A total of 17 mutants (47%) possessed at least one growth or developmental phenotype. We identified 18 mutants (56%) with chemical sensitivity or nutritional phenotypes (11 uniquely), bringing the total number of mutants with at least one defect to 28 (78%), including 15 mutants (75%) in the Pth11-related class. Gene expression trends for GPCR genes correlated with the phenotypes observed for many mutants and also suggested overlapping functions for several groups of co-transcribed genes. Several members of the Pth11-related class have phenotypes and/or are differentially expressed on cellulose, suggesting a possible role for this gene family in plant cell wall sensing or utilization

N-acetyl cysteine reverses social isolation rearing induced changes in cortico-striatal monoamines in rats

Schizophrenia is causally associated with early-life environmental stress, implicating oxidative stress in its pathophysiology. N-acetyl cysteine (NAC), a glutathione precursor and antioxidant, is emerging as a useful agent in the adjunctive treatment of schizophrenia and other psychiatric illnesses. However, its actions on brain monoamine metabolism are unknown. Social isolation rearing (SIR) in rats presents with face, predictive and construct validity for schizophrenia. This study evaluated the dose-dependent effects of NAC (50, 150 and 250 mg/kg/day × 14 days) on SIR- vs. socially reared induced changes in cortico-striatal levels of dopamine (DA), serotonin (5-HT) noradrenaline (NA) and their associated metabolites. SIR induced significant deficits in frontal corticalDA and its metabolites, 3,4-dihydroxyphenylacetic acid (Dopac) and homovanillic acid (HVA), reduced 5-HT and its metabolite, 5-hydroxyindoleacetic acid (5-HIAA), and reduced levels of the NA metabolite, 3-methoxy-4-hydroxyphenylglycol (MHPG). In addition, significant elevations in frontal cortical NA and striatal DA, Dopac, HVA, 5-HT, 5-HIAA, NA and MHPG were also observed in SIR rats. NAC at 150 and 250 mg/kg reversed all cortico-striatal DA, Dopac, HVA, 5- HT, 5-HIAA and striatal NA alterations in SIR animals, with 250 mg/kg of NAC also reversing alterations in cortico-striatal MHPG. In conclusion, SIR profoundly alters cortico-striatal DA, 5-HT and NA pathways that parallel observations in schizophrenia, while these changes are dose-dependently reversed or abrogated by sub-chronic NAC treatment. A modulatory action on cortico-striatal monoamines may explain NACs’ therapeutic use in schizophrenia and possibly other psychiatric disorders, where redox dysfunction or oxidative stress is a causal factor