No abstract

Pheromones are known to play an important role in butterfly courtship and may influence both individual reproductive success and reproductive isolation between species. Recent studies have focused on courtship in Hipparchia butterflies (Nymphalidae: Satyrinae) emphasizing morphological and behavioural traits, as well as genetic differences. Behavioural observations suggested a role for chemical cues in mate and species recognition, where the androconial scales on the forewings of these species may be involved in chemical communication between individuals. Cchemical-mediated signals have received relatively little attention in this genus. Here, we report the results of a three-year investigation of the volatile organic compounds (VOCs) released by Hipparchia fagi and H. hermione in order to identify differences in VOCs between these species where they live in syntopy. Our study was carried out using an array of cross-selective sensors known as an "Electronic Nose" (EN) that operates by converting chemical patterns into patterns of sensor signals. While the identity of volatile compounds remained unknown, sensor signals can be compared to identify similar or dissimilar chemical patterns. Based on the EN signals, our results showed that: 1) the two sexes have a similar VOCs pattern in H. fagi, while they significantly diverge in H. hermione; 2) VOCs patterns were different between females of the two species, while those of males were not.

Transglutaminase activity was characterized in extracts of the nematode Caenorhabditis elegans using a microtiter plate method, and found to be Ca 2ϩ -dependent, optimal at pH 8.0, and to be inhibited by EGTA, ammonia, iodoacetamide and GTP. Monoclonal and polyclonal antibodies raised against human tissue transglutaminase also inhibited the activity and detected a 61-kDa protein from the worm lysate. Constitutive expression of the enzyme in the wild-type intestinal cells was revealed by immunohistochemistry. Potential protein substrates for the enzyme were found in worm lysates using a biotin-labelled amine substrate. There is a basal level of protein-bound ε(γ-glutamyl)lysine cross-links, characteristic of transglutaminase activity, formed in situ in adult wild-type animals. Developmental studies have revealed that the enzyme activity is highest in adult animals, and relatively higher in L1 larvae than in other larval stages. As compared to wild types, lower transglutaminase activity has been measured in lysates of ced-3, ced-4 and ced-9 mutants. Cross-link levels were also low in ced-4 and ced-9 mutants. By contrast, the crosslink content was high in several phagocytosis mutants. The highest concentration was found in the ced-5; ced-7 double phagocytosis mutants which carry an extra number of dead cells during their lifespan. In accordance with this finding, several transglutaminase-immunopositive cells were found in both the embryos and in the head of these double phagocytosis mutants. The results suggest that a transglutaminase is involved in, or related to, the death program of cells in C. elegans and the expression and crosslinking activity of the enzyme may be perturbed in some ced mutants.Keywords : transglutaminase ; Caenorhabditis elegans ; programmed cell death.The molecular mechanism of natural cell death in mamma-quired for the engulfment of dead cells. In mutants defective in one of these seven genes the cell corpses are not phagocytosed lian cells has not been completely clarified so far, but much information have been obtained about programmed cell death by the surrounding cells but persist. There are several double phagocytosis mutants, the ced-5;ced-7 double mutant being the (PCD) in Caenorhabditis elegans, the well-known model organism of developmental genetics. During the ontogenesis of her-most expressive phenotype [12, 13].The molecular mechanisms that control PCD seem to be maphrodite nematodes, about 1090 somatic cells are generated from which 131 cells undergo PCD [1,2]. The morphology of conserved throughout the animal kingdom [14, 15]. The ced-9 gene of C. elegans is a functional homolog of the mammalian cells undergoing death in C. elegans has been described; it shares several features of apoptosis observed in mammals [1,3]. cell death suppressor gene bcl-2 [16, 17] and bcl-2 can block PCD when it is expressed in the nematode [18]. A number of genes [4] that are involved at various steps of this process were described defining a genetic pathway for proThe ced-3 gene encodes a protein ...