Anti-predator adaptations in a neustonic insect (Velia caprai)

Summary The risk of a Velia caprai (Heteroptera: Veliidae) individual to fall victim to brown trout (Salmo trutta) was demonstrated experimentally to be markedly lower when several bugs were simultaneously exposed to the trout. V. caprai was found distasteful to brown trout, and a high proportion was ejected alive after being captured. We suggest that school formation in V. caprai lowers the risk of predation because frequent predator-prey encounters may assist in retention of the avoidance learned by the predator. Individual behavioural responses to attacks were variable and the frequency of expansion skating and thanatosis was temperature dependent. Thanatosis postures were either symmetric with the legs pressed to the body or irregular.     

Stimulation par la lumière rouge lointain de la synthèse de la δ-aminolévulinate déshydratase des cotylédons de radis

Stimulation of de novo synthesis of δ-aminolevulinate dehydralasc of radishes grown under far-red light .
Density labelling studies of δ-aminolevulinate dehydratase (ALAD) in cotyledons of radish ( Raphanus sativus L. cv. Longue Rave Saumonée) seedlings demonstrate that far-red light stimulates de novo synthesis of ALAD and that the turn-over of this enzyme is very poor. Cycloheximide reduces considerably both the increase of ALAD activity and the incorporation of deuterium in ALAD, which indicates that ALAD synthesis depends upon cytoplasmic ribosomes.     

Mesenchymal-epithelial conversions induced by 5-Azacytidine: Appearance of cytokeratin Endo-A messenger RNA

When mouse-teratocarcinoma-derived fibroblasts (1246 cell line) are subjected to treatment with the inhibitor of DNA methylation, 5-Azacytidine (5 AzaC), they transiently express at 55-kilodalton intermediate-filament protein recognized by the epithelial-specific monoclonal antibody, TROMA-1, although they retain a fibroblastic morphology. However, rare clones (e.g., the 1339 cell line) that permanently express the antigen recognized by TROMA-1 can be derived from the 5 AzaC-treated 1246 population, and these clones have an epithelial phenotype. In the present study, we used cloned DNA probes to demonstrate that, in 1246 fibroblasts, 5 AzaC induces the appearance of Endo-A mRNA. High levels of Endo-A mRNA were also detected in the epithelial derivative, cell line 1339. In both cases, the capping site of the Endo-A mRNA was found to be the same as that in epithelial cells which normally express this RNA.     

BCG immunotherapy in stage I melanoma patients

Summary Previously, we have provided evidence for a positive correlation between HLA-DR expression in primary melanoma and early metastasis [3, 4]. In the present study we investigated whether this relationship was modified by adjuvant BCG immunotherapy. The study comprised 107 patients with a stage I high-risk melanoma; 44 patients had been treated with BCG, whereas the remaining patients had not received any adjuvant therapy. There was no difference in disease-free survival between BCG-treated and untreated patients. Disease-free survival was significantly shorter in patients with high expression of HLA-DR antigens in the primary tumor.Subgrouping BCG-treated and control patients according to HLA-DR phenotype of the melanoma revealed a prolongation of disease-free survival in the subgroup of BCG-treated patients with no or low expression of HLA-DR antigens in the primary melanoma. BCG therapy apparently did not influence prognosis of patients with high expression of HLA-DR antigens in the tumor.     

Inhibition, by an amphiphilic substance, niflumic acid, of the inward rectification of the crustacean muscle fiber

Agents such as TEA+ or CS+ ions, these last ions instead of K+ ions in poor K extracellular solution, known to reduce or abolish the inwardly rectifying channel in many preparations produced no effect in crayfish muscle membrane By contrast, poor Cl extracellular solution (Cl- ions were replaced by CH3OSO3- ions) blocked the inward current activated by hyperpolarizing pulses and produced an increase of the resting potential. Niflumic acid is a agent which inhibited the inward going rectification of the crayfish muscle membrane. Apparent dissociation constant of niflumic acid with membrane sites was equal to about 6 X 10(-8) M; this value corresponds to that given by Cousin & Motais (1979) concerning translocation of Cl- ions in the membrane of red cells. Activation of the inward going rectification in the crayfish membrane is responsible of an inward current carried by Cl- ions.     

Age-Related Changes in Aldehyde Dehydrogenase Activity of Rat Brain, Liver, and Heart

Abstract: Aldehyde dehydrogenase (ALDH) activity was measured in brains, livers, and hearts of 23–26-month-old and 3-month-old rats. A significant increase of ALDH activity was found in whole brain of old rats with both acetaldehyde (39%) and propionylaldehyde (15%) used as substrates. In different brain areas of old rats, with acetaldehyde used as substrate, a significant increase of ALDH activity was found in striatum (30–50%) and cerebral cortex (37%). However, no significant difference in ALDH activity was found in livers and hearts of young and old rats. Preliminary experiments showed a significant increase of aldehyde reductase activity (52%) with p -nitrobenzaldehyde used as substrate in whole brain of old rats compared with young rats. The present work indicates that an increase of ALDH activity in brain of old rats may be an adaptive phenomenon.     

A cDNA clone containing the entire coding sequence of a mouse H-2Kd histocompatibility antigen

We have isolated a cDNA clone carrying a 1560 bp long insert which contains the entire coding and 3' untranslated regions of an H-2K(d) mouse histocompatibility antigen. Its sequence and overal features are described. They point to the existence of unique properties of DNA sequences associated with the H-2K(d) antigen.     

Les effets de recristallisation sur la paroi des Involutinidae (Foraminifères) triasiques

The different types of recrystallization which can be observed in the Triassic involutinids should be considered in the taxonomic treatment of this foraminiferal family. If the diagenetic modifications of the test are neglected the same form could be placed into different suborders. Our inclusion of the genusTriasina Majzon in the Involutinidae proposed earlier on purely morphologic grounds, seems to be supported by the fact that the same types of recrystallization exist inTrocholina, Involutina undTriasina.