Rôle du Système Nerveux Sur la Prolifération Cellulaire des Blastèmes de Régénération de Membre de Triton (Pleurodeles Waltlii Michah)

Cellular proliferation of both epidermal and mesenchymal cells of denerved cone stage limb blastemas ( Pleurodeles waltlii Michah) was studied in vivo. The mitotic index and thymidine ³H incorporation (autoradiography following short term (1 hr) incubation and scintigraphy) show that denervation causes a significant decrease in the cellular proliferation (about 70% 4 days after denervation). Denervation affects first the mesenchymal cells, the proliferation of epidermal cells declines later. These results are discussed in term of cellular cycle.     

Host deprivation influence on response of Rhagoletis pomonella to its oviposition deterring pheromone

ABSTRACT. The response of host-depibved Rhagoletis pomonella Walsh (Diptera, Tephritidae) females to host fruit ( Crataegus viridis L.) marked with R.pomonella oviposition deterring pheromone was measured in the laboratory. A positive correlation was found between length of host deprivation (5, 10, 20, 40 or 80 min) and probability of host acceptance (i.e. oviposition) by flies. The results are discussed in relation to current theories on physiological control of insect feeding and oviposition behaviour.     

Changing Sink Demand Affects the Area but not the Specific Activity of Assimilate Sources in Cantaloupe (Cucumis meloL.)

To better understand source-sink interactions, this work focusedon the influence of fruit number on leaf area and photosyntheticactivity in cantaloupe. To this end, flowers were removed over2 years on two Charentais cultivars to obtain single-fruit plantsand plants with an unrestricted fruit load (which set two tofive fruits and constituted control plants). At the whole plantscale, net photosynthesis was reduced by about 30% under highfruit load. At the leaf scale, a submodel of stomatal conductancewas fitted to the data and was included in a rectangular hyperbolamodel of leaf photosynthesis. Maximum leaf net photosynthesisaveraged 14.83 µmol CO₂m^-2s^-1at 1000 µmol quantam^-2s^-1. Light use efficiency was not affected by fruit loadand equalled 0.040 mol CO₂mol^-1quanta. Leaf area of plants withunrestricted fruit load decreased after 24 days from pollination,while the leaf area of single-fruit plants was still increasing.The decrease was due to production of fewer new leaves per day,whereas the number of senescent leaves and the size of individualleaves were not affected by the treatment. Under high fruitload, cultivar Galoubet developed a larger projected leaf areathan cultivar Talma. Thus it is concluded that: (1) large cantaloupefruits may divert a large amount of assimilates away from, andgrow at the expense of, the canopy; and (2) photosynthesis ofthe canopy was lowered because leaf area was reduced whereasphotosynthetic rate of leaves was not altered.Copyright 1998Annals of Botany Company. Cucumis meloL., fruit load, source-sink interactions, leaf photosynthesis, canopy photosynthesis, leaf area, SLA, source strength.     

Herpetomonas dedonderi N. Sp. (Sarcomastigophora,Trypanosomatidae) from Haemagogus janthinomys Dyar, 1921 (Diptera,Culicidae)1

ABSTRACT. A new species of Herpetomonas was isolated from the intestinal tract of a mosquito, Haemagogus janthinomys, in French Guiana (South America). Ultrastructure, growth in various culture media, and morphological changes are presented. The name, Herpetomonas dedonderi, is proposed for this new species of lower trypanosomatid.     

Immunological Characterization of Trichocyst Proteins In the Ciliate Pseudomicrothorax Dubius

ABSTRACT. Ejectable trichocysts were isolated from the ciliate Pseudomicrothorax dubius. Polyclonal antibodies were raised against three groups of trichocyst proteins: G1 (30-31 kDa), G2 (26-27 kDa) and G3 (15-20 kDa). By indirect immunofluorescence, the three antisera strongly label the shafts of ejected trichocysts and the proximal ends of condensed trichocysts within the cells. By immunogold labeling for electron microscopy, the three sera specifically recognize the shafts of both extended and condensed trichocysts and shaft precursors in pretrichocysts as well. On one-dimensional immunoblots of isolated trichocysts, anti-G1 serum recognizes the G1 proteins, anti-G2 serum detects G2 proteins and some G1 proteins, and anti-G3 serum reacts with 15 bands, mainly the G3 and (30-41)-kDa proteins. In cells with and without trichocysts, the sera recognize non-ejectable trichocyst proteins at 41-42 kDa and 47 kDa. On two-dimensional immunoblots of isolated trichocysts, anti-G1 serum labels proteins with a pI of 4.75-5.7, anti-G2 serum labels proteins with a pI of 4.75-6.25 and anti-G3 serum labels proteins with a pI of 4.7-6.6. Analyses of cells with and without trichocysts allow identification of possible precursors between 41 and 47 kDa. Some are in the same pI range as their putative products, but others, labeled by anti-G3 serum, are less acidic than most of their mature products.     

All-female broods in Hypolimnas bolina (L.) A re-survey of West Fiji after 60 years

In the Xymphalid butterfly Hypolimnas bolina (L.) H. W. Simmonds in 1921 demonstrated, by breeding experiments, the occurrence on the islands of West Fiji of all-female broods, and he compared their frequency with that of normal bisexual broods in the same localities. In two areas he found only unisexual families (14 of them in Suva and one on Vanua Levuj, in one island (Ovalau) only a single bisexual brood and in the other two islands, Taveuni and Kandavu, one bisexual and one of each type respectively. Nearly 60 years, and probably at least 150 generations later, we found that all-female broods were still present in four of the five islands re-investigated, and breeding showed that in these four (which included Suva) the proportion of the two types of female was approximately equal. In the fifth island only a bisexual family was bred. The only marked change between 1921 and 1980 was in the Suva area, where Simmonds found far more unisexual females than we did.
By carrying out spermatophore counts in many of our wild females we found that almost all of them had been mated, the majority of them on one occasion only. Though the data are scanty, they suggest that there is no wastage of females and that the population in 1980 was stable for the two types of brood.
Reasons for our findings are discussed, particularly in the light of the Heuch model, but we conclude that no entirely satisfactory explanation has yet been given for the persistence of all-female broods. Again, there is so far no explanation of the mechanism though we favour a cytoplasmic factor.
We feel that the status of H, bolina as a mimic of species of Euploea is less assured as the result of our survey.