Gastrointestinal somatostatin cells in the human fetus

Summary The stomach, duodenum, jejunum and ileum from 6 to 24 week-old human fetuses or deceased premature infants and from one totally anencephalic fetus were stained with antisomatostatin serum. The somatostatin containing cells appear in different segments of the gastrointestinal tract from the tenth week of gestation. The somatostatin-containing cells are lead haematoxylin positive. Somatostatin was also detected in the duodenum of the anencephalic fetus. The study of inhibition of the immunofluorescent reaction by homologous and heterologous antigens confirmed the specificity of antiserum.These data demonstrate that somatostatin can be synthetized elsewhere than in the hypothalamus.We are indebted to Professor P. Magnin, Hôpital Edouard Herriot, Professor M. Dumont, Hôpital de la Croix-Rousse, Professor Notter and Professor Garmier, Hôtel Dieu, Professor M. Bethenod, Hôpital Debrousse, Lyon, whose kind cooperation allowed us to carry out the rapid removal of gastrointestinal tracts for these studies. We thank Professor Assan, Hôtel Dieu, Paris and Professor Lambert U. 45, Inserm, Lyon, who graciously provided us with antisera. We also wish to express our gratitude to Professor Roger Guillemin, The Salk Institute, La Jolla, California, whose interest and cooperation made these studies possible.This work was supported by a grant of the Institut National de la Santé et de la Recherche Médicale.     

Anthocyanin inheritance in petals of flax, Linum usitatissimum

Twelve anthocyanins have been isolated from flax: the 3-glucosylrutinosides of pelargonidin, cyanidin and delphinidin; the 3-triglucosides of delphinid     

The effect of microbial mycolytic agents on Trichophyton rubrum

Chitinolytic microorganisms isolated from forest soil and from healthy gypsy moth larvae (Porthetria dispar (L.) were screened for their ability to lyse Trichophyton rubrum mycelia. A few of these isolates were mycolytic on both autoclaved and on actively growing, intact, T. rubrum mycelia. Supernatants from these isolates, utilizing live T. rubrum as the sole carbon source, showed the same mycolytic ability. Assays of the supernatants for enzymatic activity revealed exocellular, stable enzymes that releases reducing substances including N-acetylglucosamine from the mycelia.     

Effect of a Bacillus subtilis strain on flax protection against Fusarium oxysporum and its impact on the root and stem cell walls

In Normandy, flax is a plant of important economic interest because of its fibres. Fusarium oxysporum, a telluric fungus, is responsible for the major losses in crop yield and fibre quality. Several methods are currently used to limit the use of phytochemicals on crops. One of them is the use of plant growth promoting rhizobacteria (PGPR) occurring naturally in the rhizosphere. PGPR are known to act as local antagonists to soil‐borne pathogens and to enhance plant resistance by eliciting the induced systemic resistance (ISR). In this study, we first investigated the cell wall modifications occurring in roots and stems after inoculation with the fungus in two flax varieties. First, we showed that both varieties displayed different cell wall organization and that rapid modifications occurred in roots and stems after inoculation. Then, we demonstrated the efficiency of a Bacillus subtilis strain to limit Fusarium wilt on both varieties with a better efficiency for one of them. Finally, thermo‐gravimetry was used to highlight that B. subtilis induced modifications of the stem properties, supporting a reinforcement of the cell walls. Our findings suggest that the efficiency and the mode of action of the PGPR B. subtilis is likely to be flax variety dependent.     

The rates of introgression and barriers to genetic exchange between hybridizing species: sex chromosomes vs autosomes

Interspecific crossing experiments have shown that sex chromosomes play a major role in reproductive isolation between many pairs of species. However, their ability to act as reproductive barriers, which hamper interspecific genetic exchange, has rarely been evaluated quantitatively compared to Autosomes. This genome-wide limitation of gene flow is essential for understanding the complete separation of species, and thus speciation. Here, we develop a mainland-island model of secondary contact between hybridizing species of an XY (or ZW) sexual system. We obtain theoretical predictions for the frequency of introgressed alleles, and the strength of the barrier to neutral gene flow for the two types of chromosomes carrying multiple interspecific barrier loci. Theoretical predictions are obtained for scenarios where introgressed alleles are rare. We show that the same analytical expressions apply for sex chromosomes and autosomes, but with different sex-averaged effective parameters. The specific features of sex chromosomes (hemizygosity and absence of recombination in the heterogametic sex) lead to reduced levels of introgression on the X (or Z) compared to autosomes. This effect can be enhanced by certain types of sex-biased forces, but it remains overall small (except when alleles causing incompatibilities are recessive). We discuss these predictions in the light of empirical data comprising model-based tests of introgression and cline surveys in various biological systems.     

PON1 Paraoxonase Activity is Reduced During HDL Oxidation and is an Indicator of HDL Antioxidant Capacity

The aim of this study was to investigate the effect of HDL oxidation on PON1 paraoxonase activity. Also, we were interested in investigating the mechanism by which PON1 could be inactivated and the correlation between its enzymatic activity and the antioxidant properties of HDL. Three different oxidation systems were used for the HDL oxidation: (1) oxidation induced by THP1 cells, (2) oxidation induced by copper ions at a concentration 10 &#119 M, and (3) oxidation induced by &#148 OH and O 2 &#148 &#109 oxygen free radicals produced by &#110 -radiolysis. HDL oxidation was followed by the measurement of lipid peroxide formation, and PON1 activity was determined by measuring the rate of paraoxon hydrolysis. Our results show that HDL oxidation is accompanied by a reduction in the PON1 paraoxonase activity. The extent of PON1 inactivation depends both on the extent of HDL oxidation and on the oxidation system used. The rates of HDL oxidation and PON1 inactivation were significantly correlated ( r =0.93, p <0.0054). Our results show that oxidized HDL loses its protective effect toward LDL oxidation. The antioxidant action of HDL towards LDL oxidation and the degradation of PON1 paraoxonase activity were significantly correlated ( r =0.95, p <0.04).     

Synthesis and Cytotoxic Evaluation of Novel Thiazolocarbazoles. Part II1

Novel thiazolocarbazole derivatives have been synthesized via the corresponding imino-1,2,3-dithiazoles. In vitro antitumor activity of these polyheterocyclic compounds was studied.     

Synthesis and Cytotoxic Evaluation of Novel Thiazolocarbazoles

Novel thiazolocarbazole derivatives 4 and 5 have been synthesized via the corresponding imino-1,2,3-dithiazoles 3. In vitro antitumor activity of these polyheterocyclic compounds was studied and the results show that 2-cyano derivatives exhibit a medium in vitro antiproliferative effect.