New methods for binding enzyme molecules into a water-insoluble matrix: Properties after insolubilization

New methods of crosslinking enzyme molecules inside a matrix with or without an inactive protein are described. Enzyme activity yields range between 30 and 80% of the activity of the untreated preparations. Even fragile enzyme systems, for instance those using mobile cofactors, can be efficiently immobilized. Increased resistance towards heat denaturation and proteolysis results.     

Calcium involvement in the muscarinic response of the gastric parietal cell

The influence of extracellular Ca2+ on the mediation of carbachol stimulation in isolated rabbit gastric parietal cells was studied. Removing Ca2+ from extracellular medium caused a 42% decrease of the aminopyrine accumulation due to carbachol with the same EC50 value (approximately 5 microM). A short time depletion in extracellular calcium suppressed the carbachol-dependent Ca2+ influx without affecting Ca2+ release from internal stores (fura-2 measurements). Similarly, the production of inositol phosphates under cholinergic stimulation was reduced by 29%. A rapid increase in Ins(1,4,5)P3 was obtained 5 s after carbachol stimulation, and this increase was not changed in Ca2(+)-depleted medium. In contrast, a 20 min incubation with carbachol caused a 50% reduction in both basal and carbachol-stimulated inositol phosphate accumulations. In conclusion, phospholipase C activation, intracellular Ca2+ release and aminopyrine accumulation were sequentially observed following carbachol stimulation of the isolated gastric parietal cell and extracellular calcium contributed to sustain this acid secretory response.     

Synthesis and primary cytotoxicity evaluation of arylmethylenenaphthofuranones derivatives

New series of 2(or 3)-arylmethylenenaphtho[2,1-b]furan-3(or 2)-ones were synthesized, characterized and tested for anticancer properties in vitro. The target compounds were prepared by Knoevenagel coupling between the naphthofuranones 3, 28–30 and formyl derivatives. 2-(4-Oxo-1-benzopyran-3-ylmethylene)naphtho[2,1-b]furan-3-one 36 was the most active compound (IC₅₀ (L1210) = 1.6 μM). These compounds were also evaluated, in an independent manner, as inhibitors of Src protein tyrosine kinase, but only minor activity was observed.     

Design of new antifungal agents: synthesis and evaluation of 1-[(1H-indol-5-ylmethyl)amino]-2-phenyl-3-(1H-1,2,4-triazol-1-yl)propan-2-ols

We previously reported on the design and synthesis of 1-[((hetero)aryl- or piperidinylmethyl)amino]-2-phenyl-3-(1H-1,2,4-triazol-1-yl)propan-2-ols showing various degrees of antifungal activity against Candida albicans and Aspergillus fumigatus strains. Now we have identified a series of 1-[(1H-indol-5-ylmethyl)amino] derivatives which exhibited potent MICs (<65 ng mL^?1) against C. albicans strain. The synthesis and SAR behind the indole scaffold will be discussed.     

The multifunctional protein GC1q-R interacts specifically with the i3 loop arginine cluster of the vasopressin V2 receptor

In this study, we identified the multifunctional protein GC1q-R as a novel vasopressin V(2) receptor (V(2)R) interacting protein. For this purpose, we have developed a proteomic approach combining pull-down assays using a cyclic peptide mimicking the third intracellular loop of V(2)R as a bait and mass spectrometry analyses of proteins isolated from either rat or human kidney tissues or the HEK 293 cell line. Co-immunoprecipitation of GC1q-R with the c-Myc-tagged h-V(2)R expressed in a HEK cell line confirmed the existence of a specific interaction between GC1q-R and the V(2) receptor. Then, construction of a mutant receptor in i3 loop allowed us to identify the i3 loop arginine cluster of the vasopressin V(2) receptor as the interacting determinant for GC1q-R interaction. Using purified receptor as a bait and recombinant (74-282) GC1q-R, we demonstrated a direct and specific interaction between these two proteins via the arginine cluster.     

Pharmacomodulation on the 3-acetylursolic acid skeleton: Design, synthesis, and biological evaluation of novel N-{3-[4-(3-aminopropyl)piperazinyl]propyl}-3-O-acetylursolamide derivatives as antimalarial agents

A series of new piperazine derivatives of ursolic acid was synthesized and tested against Plasmodium falciparum strains. They were also tested on their cytotoxicity effects upon MRC-5 cells. Seven new piperazinyl analogues showed significant activity in the nanomolar range (IC(50)=78-167nM) against Plasmodium falciparum CQ-resistant strain FcB1. A possible mechanism of interaction implicating binding of these compounds to beta-hematin was supported by in vitro tests. Moreover, the importance of the hydrophilic framework attached at the terminal nitrogen atom of the bis-(3-aminopropyl)piperazine joined to the triterpene ring was also explored through molecular dynamic simulations.     

Spatial variation in springtime food resources influences the winter body mass of roe deer fawns

It is well established that the dynamics of mammalian populations vary in time, in relation to density and weather, and often in interaction with phenotypic differences (sex, age and social status). Habitat quality has recently been identified as another significant source of individual variability in vital rates of deer, including roe deer where spatial variations in fawn body mass were found to be only about a tenth of temporal variations. The approach used was to classify the habitat into blocks a priori, and to analyse variation in animal performance among the predefined areas. In a fine-grained approach, here we use data collected over 24 years on 1,235 roe deer fawns captured at known locations and the plant species composition sampled in 2001 at 578 sites in the Chizé forest to determine the spatial structure at a fine scale of both vegetation and winter body mass of fawns, and then to determine links between the two. Space and time played a nearly equal role in determining fawn body masses of both sexes, each accounting for about 20% of variance and without any interaction between them. The spatial distribution of fawn body mass was perennial over the 24 years considered and predicted values showed a 2 kg range according to location in the reserve, which is much greater than suggested in previous work and is enough to have strong effects on fawn survival. The spatial distribution and the range of predicted body masses were closely similar in males and females. The result of this study is therefore consistent with the view that the life history traits of roe deer are only weakly influenced by sexual selection. The occurrence of three plant species that are known to be important food items in spring/summer roe deer diets, hornbeam (Carpinus betulus), bluebell (Hyacinthoides sp.) and Star of Bethlehem (Ornithogalum sp.) was positively related to winter fawn body mass. The occurrence of species known to be avoided in spring/summer roe deer diets [e.g. butcher's broom (Ruscus aculeatus) and beech (Fagus sylvatica)], was negatively related to fawn body mass. We conclude that the spatial variation in the body mass of fawns in winter in this forest is as important as the temporal variation, and that the distribution of plant species that are actively selected during spring and summer is an important determinant of spatial variation in winter fawn body mass. The availability of these plants is therefore likely to be a key factor in the dynamics of roe deer populations.