Isolation of insecticidal proteins within the pea seeds (Pisum sativum L.)

Poster (2006, October)

Consequently with the pressure exerted by chemical pesticides on environment, and the awakening of politics, the demand for bio-pesticides is increasing. Nevertheless, supply is not sufficient, and ... [more ▼]

Consequently with the pressure exerted by chemical pesticides on environment, and the awakening of politics, the demand for bio-pesticides is increasing. Nevertheless, supply is not sufficient, and moreover those products are not competing enough. In this context, the aim of this research is to set up a biological insecticide, which is economic, with vegetal proteins resulting from alimentary industry, here the pea, Pisum sativum L.. A group of proteins, which is quite easy to highlight, is present in relatively important proportions (2%) in pea seeds, it’s the lectins class. Insecticidal effects of lectins from different organisms have already been proved. Indeed, by binding to membrane glycosyl groups of digestive tract cells, lectins can be very toxic for a lot of insects. Thus initially we focus our investigations on Pisum sativum lectins (PSL). First, PSL have been localised within the industrial process among different extraction juices. Then, a chromatography has been performed on the selected juice with FPLC technology. Although the matrix used for this chromatography, sephadex G75, is a banal bed for gel filtration, it is in this case a real combination between classical gel filtration and affinity chromatography. Indeed due the particular properties of lectins, they fixed carbonyl group of the bed and have to be eluted after the filtration part with a solution of glucose. Then the collected fractions corresponding to UV-peaks on the chromatogram were separated by electrophoresis 2D and identified by mass spectrometry (ESI MS/MS) coupled with data bank investigations. Secondly bioassays using artificial diets have been developed on Myzus persicae in the aim to study the aphicid effects of theses fractions with rm and LC50.These estimators show significant mortality rates but also change in the fecundity and in the development of nymph. [less ▲]

Mapping and polymorphism of bovine ghreline gene

Poster (2006, August)

Bovine ghrelin, a 27-amino-acid peptide has been identified in bovine oxyntic glands of the abomasum. It is an endogenous growth hormone secretagogue. Total mRNA was extracted from abomasum and complete ... [more ▼]

Bovine ghrelin, a 27-amino-acid peptide has been identified in bovine oxyntic glands of the abomasum. It is an endogenous growth hormone secretagogue. Total mRNA was extracted from abomasum and complete ghrelin mRNA was sequenced by rapid amplification of cDNA ends. The gene contains five exons and four introns with a short noncoding first exon of 17 bp similar to mouse and human ghrelin gene. Using a radiation hybrid panel, the gene was mapped to chromosome 22 near microsatellite markers UWCA49, BM4102, BMS1932, BM2613 and URB035 with good LOD Score. Some studies detected different QTLs near these markers like for milk fat percent, milk protein percent and somatic cell score. So, it would be interesting to study the polymorphism on the bovine ghrelin gene. Screening for polymorphisms in the five exons and the introns II and IV on ten Belgian Blue bulls, ten Holsteins bulls and ten Limousin bulls revealed a total of three single nucleotide polymorphisms. In order to evaluate if ghrelin could be involved in genetic variation for milk fat percent, milk protein percent and somatic cell score an association study between SNPs on ghrelin gene and these traits could be performed in a major cattle population. [less ▲]

Insulin-like growth factor binding proteins (IGFBPs) in camels : revelation by western ligand blotting and partial purification of insulin-like growth factor binding protein-3 (IGFBP3)

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2004), 8(Special issue), 53

It's well known that Insulin-like growth factor binding proteins (IGFBPs) are important in somatotrope axis in mammals. They modulate bioactivity of Insulin-like growth factor-I/II. In this study, we ... [more ▼]

It's well known that Insulin-like growth factor binding proteins (IGFBPs) are important in somatotrope axis in mammals. They modulate bioactivity of Insulin-like growth factor-I/II. In this study, we identified IGFBPs in blood of camel by Western ligand blotting and we investigated a procedure to purify IGFBP-3 from this species. Three distinct bands are observed. By analogy to that known in mammals, they are identified as insulin-like growht factor binding-3 (IGFBP-3:40-46 kDa), insulin-like growth factor binding proteins-2 (IGFBP-2: 32 kDa) and insulin-like growth factor binding proteins-1 (IGFBP-1: 28 kDa). IGFBP-3 precipitates in 40-60% by ammonium sulfate saturation of serum. Acidification of 40-60% fraction at pH 3.0 is necessary to dissociate IGFBP-3 from tertiary complex (IGFBP-3, acid labile subunit and IGF-I/II). IGFBP-3 is partially purified by anionic ions exchange chromatography at pH 8.5. It forms a clear doublet band. [less ▲]

Effets d'une immunomodulation de la leptine et de la cholécystokinine chez le rat en croissance

Master's dissertation (2001)

The use of antibodies to modulate the activity of existing endocrine factors is an immunomodulation. The meal-related intestinal signal cholecystokinin (CCK) and the adipose tissue-produced leptin are ... [more ▼]

The use of antibodies to modulate the activity of existing endocrine factors is an immunomodulation. The meal-related intestinal signal cholecystokinin (CCK) and the adipose tissue-produced leptin are known as satiety hormones. Their interaction induces long- and short-terms effects. The aim of this study is to examine the zootechnical and endocrinal effects of an active immunomodulation of both CCK and leptin. Three experiments are realized. Two of them are single or double active immunization of rats against the cholecystokinin 33 (CCK-33), the unsulfated cholecystokinin octapeptide (CCK- 8ns) and the leptin. The last experiment consists in injecting leptin and CCK-8ns into immunized rats. More than 60 % of the concerned rats are really immunized against CCK-33 or CCK-8ns. Few rats develop antibodies against leptin. Very few rats respond to the double immunization against CCK and leptin. In the first experiment, the immunomodulation of CCK-8ns reduces food intake and growth. The leptin-immunized rats eat the most (P < 0.05). The second experiment shows that the immunomodulation of CCK-8ns stimulates growth by 8 % in the second part of the experiment. In both experiments, all the leptin-treated rats have a smaller feed efficiency than the control group during the second week (P < 0.05). The feed efficiency of the control group is the highest until the fourth week. We don’t observe any difference in weight lost between control rats, which get leptin and CCK-8ns injections, and control rats with saline solution injections. Rats which develop CCK-8ns antibodies and get leptin and CCK-8ns injections lose more weight than rats that develop these antibodies and get saline solution injections (P < 0.03). The endocrinal parameters of the second experiment show that leptin-immunized rats have more serum leptin than the control group (P < 0.03). We note more serum IGFBP-3 in CCK-8ns- and leptin-immunized rats than the others (P < 0.001) and less T3 and T4 in their bloodstream (respectively P < 0.004 and P < 0.002). In conclusion, the small immune response against leptin had to limit the zootechnical and endocrinal effects. New techniques must be developed in order to generate a better immune response essentially against leptin. [less ▲]