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Corchorus olitorius L. is one of the traditional leafy vegetables of high food and socio-economic value in Africa. Although widely exploited, its varietal diversity is unknown and its domestication remains challenged by pests and diseases presently observed among subsistence users. This study aims to determine the morphotype diversity of C. olitorius in Southern Benin and the durability of its agroecosystem by the influence of agricultural practices on the major pest insects related to its production. Using participatory research methods, surveys were conducted in 21 villages randomly selected across the study area. Results revealed seven different morphotypes of C. olitorius, three of which were wild but used in traditional medicine and four were cultivated. Among the nine constraints reported by farmers, the attack of seven pest insects and the non-distinction of the seeds of the different cultivated morphotypes are the two most important constraints. The seven most common potential pest insects observed by between 10–100% of the farmers, in study area are: Acrea sp, Aulacophora Africana, Helicoverpa armigera, Spodoptera litoralis, Zonocerus variegatus, Podagrica spp. and Acrea acerata. The infestation by these insects were not linked to specific morphotypes of C. olitorius, but varied by locality. The agricultural practices that might influence the presence of any C. olitorius pests were intercropping and dormancy cutting, seedling after sowing and number of harvests. This information will contribute to a better production of the varieties of C. olitorius and the different crop associations could be integrated into methods of ecological management of the pests of C. olitorius.

The African eggplant (Solanum aethiopicum L.) is an important traditional vegetable cultivated in tropical regions for its edible fruits. In the Benin Republic, S. aethiopicum is mainly cultivated by rural farmers for food and for its use in traditional medicine. Assessing varietal diversity, endogenous knowledge, production constraints and farmers' preference criteria are of great importance for promotion and conservation purposes. Using rural appraisal tools and methods, an ethnobotanical study was conducted in 680 households across 92 villages. A total of 60 local cultivars were collected and documented in the surveyed sites. We documented 15 farmers’ criteria for agronomic (57.88% of responses), culinary (28.51%) preference, and for economic (13.61%) aspects. Several constraints related to eggplant production in Benin were also recorded. The low market demand (27% of responses), lack of high-yielding cultivars (11.08% of responses), low fruit storability (10.67%), low productivity (9.84%), soil poverty (8.43%), susceptibility to high soil moisture (8.02%), pests (9.56%), diseases (8.45%), and drought (6.38%) appeared to be the most important constraints of the eggplant production system in Benin. In addition to synthetic pesticides, the eggplant farmers use botanical plant extracts such as extracts from Azadirachta indica (Meliaceae) and Hyptis suaveolens (Lamiaceae). It appears that eggplant production is still traditional and is of limited use in Benin. Finally, the currently collected germplasm was proposed for further evaluation using morphological and molecular markers to provide breeders with traits of interest for developing better eggplant varieties and hybrids that are suitable for local environmental conditions and production systems.

The individual and combined influences of various geochemical constituents, i.e., calcium, phosphate, silicate, and humic acid, on simultaneous removal of chromium and arsenate by ferrous iron were studied under suboxic conditions. The single presence of Ca2+ up to 50 mg L−1 showed negligible effect on chromium removal throughout the pH range of 4–10 but the presence of 50 mg L−1 Ca2+ increased arsenate removal by 16.8–21.6% at pH >7. The presence of phosphate or humic acid increased Cr(VI) reduction by Fe(II) at pH

Hepatocyte growth factor (HGF) regulates a wide variety of biological activities by binding to the tyrosine kinase receptor Met. In HGF-treated hepatocarcinoma cells, we observed a biphasic activation of AP-1 and AP-2 transcription factors. For NF-kappaB complex the p50-p50 homodimer was activated before the p50-p65 heterodimer, and c-Myc/Max DNA-binding activity increased thereafter. Since these transcription factors are responders to mitogenic stimulation through protein kinase transducers, we tested the effects of inhibitors of these enzymes on the DNA binding after HGF treatment. Inhibition of protein kinase C (PKC) with H7 strikingly activated NF-kappaB above the values observed after HGF alone. Under this inhibitory condition, Met tyrosine phosphorylation was elevated as though the phosphorylation-dependent activity of the receptor was partially blocked by activation of PKC due to HGF. NF-kappaB DNA binding seems to be related to Met triggering by HGF since it was largely prevented by genistein treatment, which blocks receptor activity. Phosphatidylinositol 3-kinase seems to be involved in AP-1 binding activity stimulated by HGF. It is noteworthy that Met is responsive to HGF stimulating postreceptor signaling, which converges on the activation of transcription factors acting coordinately to regulate target gene expression.

We have previously shown that polyamine levels rapidly decrease in thymocytes undergoing apoptosis, and that ornithine decarboxylase increases early but too transiently to maintain elevated polyamine levels. These data led us to suppose that a precocious ornithine decarboxylase degradation might be responsible for the imbalance of polyamine metabolism. Ornithine decarboxylase is known to be degraded by the cytosolic 26S proteasome that plays an essential role in thymocyte apoptosis. In this paper we demonstrate that the inhibition of proteasome function preserves ornithine decarboxylase activity and prevents thymocytes from undergoing apoptosis after dexamethasone treatment. Since intracellular polyamine levels are also preserved, ornithine decarboxylase seems to be functionally active in maintaining polyamine homeostasis after proteasome inhibition in thymocytes. Our proposed role for the proteasome in quiescent cells upon an apoptotic stimulus is to degrade proteins like ornithine decarboxylase that are involved in the control of the cell cycle and cell survival.

Binding of hepatocyte growth factor (HGF) to its receptor Met induces autophosphorylation and activation of the tyrosine kinase activity. In HGF-treated HepG2 cells, we studied: (i) the expression patterns of early (c-myc, c-jun, and c-fos) and delayed-early (ornithine decarboxylase and c-met) response genes and (ii) the possible involvement of protein kinase transducers in the control of the expression of c-met and of other genes eventually induced downstream. c-met and c-myc mRNAs peaked 1-2 h after HGF, while c-jun and c-fos mRNAs slightly increased at 1 h. Ornithine decarboxylase activity was induced earlier (4 h) than the mRNA (8-10 h). The transducers involved in HGF-triggered gene inductions were investigated using different protein kinase inhibitors: genistein for the receptor tyrosine kinase, herbimycin A for the nonreceptor tyrosine kinase (pp60(c-src)), wortmannin for phosphatidylinositol 3-kinase (PI3K) and H7 for protein kinase C (PKC). The similarity of responses to PKC inhibition led to suppose that c-myc and ornithine decarboxylase mRNAs were induced sequentially along the same transduction pathway triggered by HGF. Ornithine decarboxylase activity seemed to be largely regulated by phosphorylation(s). The mRNA expression of c-jun was likely to undergo a negative regulation through a mechanism involving PI3K, while that of c-met seemed to be almost independent from various protein kinases (PI3K, pp60(c-src), and PKC).