Structure des acides isomuronique et neuropogolique,nouveaux acides aliphatiques du lichen Neuropogon trachycarpus

The structures of two new aliphatic acids, isomuronic and neuropogolic acid, from the lichen Neuropogon trachycarpus, were established by spectroscopic (MS, ¹H and ¹³C NMR) and chemical evidence. Circular dichroism data allowed the configuration of isomuronic acid to be assigned as 2R.     

Étude chromatographique des acides phénoliques et des phénols obtenus par la fusion alcaline des acides humiques

Resumé Les résultats de cette étude portent principalement sur l'analyse chromatographique des acides aromatiques et phénols, obtenus après la fusion alcaline, des acides humiques, de la lignine, de mycélium de microchampignons, de la ligno-protéine, du DNA et du RNA. Par chromatographie sur papier 70 substances sont mises en évidence dont une vingtaine sont identifiées. Les acides nucleiques mis à part, l'analyse chromatographique donne des résultats pratiquement identiques pour tous les complexes éxaminés. On démontre également que l'acide 3.5-OH-Benzoique n'est pas uniquement d'origine microbienne. Par chromatographie en phase gazeuse, le phénol, o-crésol et p-crésol sont détectés dans les acides humiques, tandis que dans la lignine le m-crésol est mis en évidence en plus de trois substances citées. Recherches subsidiées par l'Institut pour l'Encouragement de la Recherche Scientifique dans l'Industrie et l'Agriculture (IRSIA)     

Etude Ultrastructurale des Mérozoites et de la Schizogonie des Coccidies (Eimeriina): Eimeria magna (Perard 1925) de I'Intestin des Lapins et E. tenella (Railliet et Lucet, 1891) des Coecums des Poulets

SYNOPSIS. An electron microscopic study is made of merozoites and schizogony of Eimeria magna and Eimeria tenella from rabbits and chickens infected 5 days before fixation.
The merozoite outer layer is formed by a unit membrane lined by a dense osmiophilic layer. A micropyle is present. The apical complex of the cell is constituted by a conoid surmounted by 2 rings and surrounded by another from which about 26 subpellicular, tubular fibrils start. Two "rhoptries" (= toxonemes) go thru the conoid to the apex of cell. Rare sarconemes (= convoluted tubes) are disseminated in the anterior part of merozoites. A nucleus with nucleolus, Golgi apparatus, mitochondria, endoplasmic reticulum, lipid globules and glucidic grains were observed.
Schizogony starts by the formation of a multinucleated schizont which has a centriolar structure. The new merozoites appear as evaginations of the schizont's membrane. Cellular organelles (conoid, rhoptries, micropyle, sarconemes) differentiate and the nuclei enter the diverticula of the schizont. Then the development of merozoites proceeds by "external budding".
The ultrastructural similarities between the merozoites of Eimeria and the endodyocytes of Toxoplasmea, appear to us to be extremely interesting and indicate a close relationship between the Toxoplasmea and the Coccidia.     

Etude de melanges binaires de triglycerides derives des acides palmitique et stearique

The phase diagrams of the SSS—PSP, PSP—SPP and SSS—SPP systems have been established, using DTA and X-ray diffraction, In all cases, a demixtion was found in the solid state, and an intermediate phase was evidenced for the PSP—SPP and SSS—SPP systems.Relations between the diagrams of stable and unstable forms are considered for the system SSS—PSP. Moreover, the influence of structuration in the liquid state on the drawing of liquidus is discussed.     

Recherches sur les enzymes catalysant la biosynthèse des acides phénoliques chez Quercus pedunculata. III. Formation séquentielle, à partir de la phénylalanine, des acides cinnamique, p-coumarique et caféique, par des organites cellulaires isolés

The reactions leading to cinnamic acids from phenylalanine as only substrate were investigated in organelles from Quercus pedunculata Ehrh. roots. –“F 10 000′” fraction, including mitochondria and micro-bodies, catalyses the first reaction, i.e., cinnamate formation by deamination of phenylalanine. – Microsomal fraction catalyses all the steps from phenylalanine to caffeic acid via cinnamate and p-coumarate. These results suggest that microsomes are the intracellular site of the cinnamic units synthesis. The enzymes involved in these reactions, associated in the same cellular compartment, does not form a multienzyme system. The formation of caffeic acid by isolated microsomes is demonstrated for the first time; the reaction may be realised by an enzyme different from phenolase. – The free phenolic acids are the metabolically active forms.     

Biosynthese des produits volatils de la pomme: Formation des alcools et des esters a partir des acides gras

The biosynthesis of apple volatiles (alcohols and esters) was studied using disks of aged tissues. After adding each substrate, the volatiles formed were analysed and estimated by GLC and their qualitative and quantitative composition compared with those of the control. Alcohols were formed from aliphatic acids having either the same number of carbon atoms, or from higher homologues through β-oxidation. Fatty acids with an even carbon number gave rise to butanol and hexanol, while odd carbon fatty acids generated propanol and pentanol. Esters were synthesized from the corresponding acid and alcohol and the yield was very high. Volatile profiles differed from one variety to another, yellow-skinned varieties producing chiefly acetic acid esters and the red-skinned mainly butyric acid esters. Provided the right substrates were given, all the esters were synthesized by the different tissues assayed, and the nature of the volatiles produced by each variety depends on the substrates present in the fruit. However, in Golden Delicious apples, which have a low content of butyric esters, erogenous butyrate was rapidly and completely transformed into acetate.     

La biodegradation des acides fulviques

The apparent difficulty of degrading fulvic acids in the aquatic environment was investigated, using samples taken during a whole annual cycle, and studying mineralisation processes caused by the action of different bacteria in samples with and without addition of benzoate and lactate. Qualitative changes in the respective ratio of various fulvic acid fractions produced by bacterial action, were studied with sephadex 25.

---

La biodegradation des acides fulviques

     

Modalités de l'inhibition de la croissance et de la synthèse des acides nucléiques des plantules de blé par l'acide abscissique

The growth of wheat seedlings (Triticum sativum) is inhibited by abscisic acid (ABA). The inhibition increases with the concentration of ABA (from 10^-6M to 5 × 10^-5M) and is stronger in the case of coleoptiles and first leaves than in roots. In contrast, naphthaleneacetic acid (ANA), at 10^-5M, exerts its greatest inhibitory effect on the roots. The inhibitory effect of ABA on coleoptiles can be partially overcome by kinetin and to a much smaller degree by gibberellic acid. Neither of these two compounds, at 10^-5M, had any effect on the ABA-induced inhibition of root growth. The RNA and DNA contents per plant organ are considerably reduced after treatment of the seedlings with ABA, particularly in the coleoptiles and the first leaves. The incorporation of uracil-2-¹⁴C and uridine T (G) into RNA of treated seedlings is reduced in the case of coleoptiles and first leaves, but considerably enhanced in roots. The mechanism of the action of ABA is discussed in the light of these results.     

Absorption des acides amines par les lutoïdes du latex d'Hevea brasiliensis

Absorption of Amino Acids by Lutoids from the Latex of Hevea brasiliensis. The latex of Hevea brasiliensis is a fluid protoplasm containing organelles with a single membrane that are called lutoids. They are microvacuoles of a lysosomal character. The intact lutoids can easily be isolated in an isotonic medium by the usual procedures of cellular fractionation. Previous studies have shown the existence of a compartmentation of the free amino acids in latex. While acidic components dominate in the cytoplasmic serum, the lutoid serum contains mainly basic components. These findings, as well as the part played by the lutoids in the latex flow and in the process of latex coagulation, led the authors to study the penetration of acidic, neutral and basic amino acids into the lutoids. Labelled amino acids were used for the purpose. Special interest was given to the uptake of lysine, which is transported into the lutoids against a concentration gradient in the absence of a metabolic energy source. The process is linear for at least 30 min and follows Michaelis–Menten kinetics as a function of the lysine concentration. The uptake is strictly temperature and pH dependent. It increases in the presence of ATP. Lysine uptake by lutoids is also increased by application of Ethrel, ethylene generator, to the bark of tapped trees. 2,4-Dinitrophenol (2,4-DNP), ammonium chloride and N-ethylmaleimide (NEM) inhibit the influx. Neutral l -amino acids do not affect the uptake of l -lysine, while l arginine inhibits lysine transport competitively. d -lysine is without effect on l -lysine uptake by lutoids. Under conditions used in this study no lysine efflux is observed. A mechanism governing the penetration of basic amino acids against a concentration gradient is discussed, and the possible role of a proton gradient is suggested.     

Cristatopecten nov. gen. benoisti (Pectinidae, Bivalvia) du Chattien d'Aquitaine (France). Révision systématique et réflexions sur l'origine et l'évolution des Cristatopecten

The detailed study of a sample of “Pecten (Amussiopecten) benoisti” Cossmann and Peyrot (1914) from the Chattian outcrops of the Adour Basin, allowed to improve our knowledge of this species poorly known till now and to show its important ornamental variability. It follows that some nomenclatural points have been clarified at the generic level: we refute the attribution of this species to the genus Amussiopecten Sacco (1897) as used by authors—genus which was besides emended several times subsequently— and we propose its allocation to Cristatopecten nov. gen. Furthermore, this study allowed to remove the ambiguity existing originally as for the attribution of the species benoisti and burdigalensis to a same genus: our comparison of the latter two taxa shows that if benoisti has to be henceforth included in the new genus Cristatopecten (as its type species), burdigalensis (which is the type species of Amussiopecten) must be incorporated in the genus Flabellipecten Sacco (1897). The two genera Amussiopecten and Flabellipecten are therefore synonymous, as Depéret and Roman had already stated in 1910. The Cristatopecten from the Old World seem to be derived from a group of “Aequipecten” notably known in the Italian Rupelian, the group of “Aequipecten deletus” (Michelotti, 1861), of which we study here a sample from the Aquitaine Chattian. In the Aquitaine Basin, the Cristatopecten are represented, in the Chattian, by Cristatopecten benoisti (Cossmann and Peyrot, 1914); in the Lower Aquitanian, by C. praehaueri (Bongrain, Cahuzac and Freneix, 1994); in the Burdigalian-Langhian of the Saubrigues paleocanyon, by C. haueri (Michelotti, 1847) and C. miogallicus (Cossmann and Peyrot, 1914). During the whole Neogene, they spread and evolved in the Tethys and the Paratethys areas, and seem to have become extinct in the Pliocene with the disappearance of C. cristatus (Bronn, 1827), a species that we consider not as an Amusium s.s., but as the last representative of the Cristatopecten phylum.     

Modifications des propriétés cytophotométriques des ADN et des histones nucléaires au cours de la sénescence des tritons (Triturus vulgaris et Triturus cristatus)

DNA and histones were studied by cytophotometry, in cartilaginous cells from urodele amphibians (Triturus vulgaris and Triturus cristatus) during ageing. With the Feulgen reaction, the DNA colorability decreased and their acid hydrolysis was more difficult. The coloration of the histones linked to DNA in chromatin was also changed. The results are discussed in relation to numerous works on deoxyribonucleoprotein modifications during cell ageing.ADN et histones ont été étudiés par cytophotométrie dans les cellules cartilagineuses d'Amphibiens Urodèles (Triturus vulgaris et Triturus cristatus) au cours du viellissement. Nous avons observé une baisse des affinités tinctoriales des ADN et une augmentation de leur résistance á l'hydrolyse acide pratiquée dans le cadre de la réaction de Feulgen. La colorabilité des histones associées aux ADN dans la chromatine est aussi modifiée. Tous ces résultats sont discutés en liaison avec les nombreux travaux effectués sur les modifications des désoxyribonucléoprotéines au cours du viellissement cellulaire.     

Activite succino-deshydrogenasique des microsomes et mode d'incorporation du succinate 2,3-(14)C dans les acides gras des microsomes de foie de rat in vitro

The incorporations of 2,3-(14)C-succinate 2-(14)C-acetate into fatty acids of different cellular fractions of rat liver were studied. Acetate was incorporated mainly into supernatant and succinate into microsomal fatty acids. Mitochondria only could intensively decarboxylate pyruvate. Avidine inhibited fatty acid synthesis from succinate mainly in the supernatant. It is suggested that succinate is an important physiological precursor of fatty acids in the liver and that an active succino-dehydrogenase is present in microsomes.     

Biosynthèse des acides gras polyinsaturés des glycérolipides de la feuille d'olivier

The patterns of incorporation of [l-¹⁴C]-acetate into the glycerolipid fatty acids of leaves of olive plants ( Olea europea L. cv. Chétoui) suggested a specific pathway for a-linolenic acid biosynthesis. The results confirmed the involvement of phosphati-dylcholine in galactolipid metabolism, and seemed to exclude the role of that mole-cule as a substrate for desaturation of oleate to linoleate. The two oleate desaturation steps seemed to occur rapidly on the diacylgalactosylglycerol molecule for biosynthesis of galactolipid linolenate. In addition, the results indicated a slow sequen-tial desaturation of oleate to linolenate via linoleate in the phospholipid molecules (phosphatidylcholine, phosphatidylethanolamine and phosphatidylglycerol).