Desangeloylshairidin,X-ray structure determination of a sesquiterpene lactone from Guillonea scabra

The structure and absolute configuration of desangeloylshairidin, a guaianolide isolated from Guillonea scabra, have been established by X-ray diffraction analysis. No conformational change was observed in its seven-membered ring between the crystal and deuterochloroform solution states.     

The reactogenicity and immunogenicity of the Urabe Am 9 live mumps vaccine and persistence of vaccine induced antibodies in healthy young children

The immunogenicity and reactogenicity of the Urabe Am 9 mumps virus vaccine strain were studied after the administration of different doses of the vaccine to 197 children ranging in age from seven and a half months to nine years and without a history of mumps. There was no effect of dose on the response in serum neutralizing antibodies in the range of 10(2.9) to 10(4.7) TCID50/dose. In the 90 subjects without detectable serum neutralization antibodies before vaccination seroconversion was obtained in 94.4% after 42 days. Half of a group of 34 seropositive children who were tested also showed a fourfold or greater rise in antibodies. Persistence of vaccine-enhanced haemagluttinin-inhibition (EHI) antibodies was satisfactory as only two of 46 vaccinees followed-up for between 27 and 32 months had undetectable levels of EHI antibodies and the geometric mean titre of vaccine-induced EHI antibodies had only fallen to about one-third by 32 months after vaccination. Although there was serological evidence of a subclinical re-infection in three subjects, to date none of the vaccinees has had clinical mumps indicating that the vaccine confers protection against disease. The vaccine was well tolerated. Furthermore, the majority of the few 'reactions' reported were probably not vaccine-related. It is concluded that the Urabe Am 9 is an acceptable strain for use in live mumps vaccines.     

Calorimetric measurement of free energy utilization by Nitrosomonas and Nitrobacter

Summary Calorimetric estimates of the utilization efficiency of the free-energy derived from substrate oxidation by cell suspensions of two nitrifying bacteria, Nitrosomonas and Nitrobacter, provided two ranges of values: 11 to 27% and 15 to 51%, respectively. About 15 to 30% of the utilized free-energy is used for driving endergonic reactions other than CO₂ fixation, probably the synthesis of polyphosphates.The molar heat of substrate oxidation does not seem to be influenced by the age of cells harvested during growth or by the length of the incubation period during which cells have been kept in a buffer suspension in a starved condition. The loss of respiratory activity measured either by oxygen uptake or heat evolution in the presence of the specific substrate, nitrite or ammonium, decreases according to kinetics which are influenced by the aerobiosis of the suspension. The viability of the starved cells decreases in a way which is similar to that of the respiratory activity. It seemed impossible to obtain cells which had lost their viability but kept the ability to oxidize their substrate.Two inhibitors of the respiratory chain, quinacrine and cyanide, are without effect on the molar heat of substrate oxidation and consequently on the free-energy utilization efficiency. 2.4 dinitrophenol did decrease the rate of heat evolution during substrate oxidation at concentrations at which the rate of oxygen uptake was not depressed, with the consequences that free-energy efficiency was apparently increased.     

L'excursion en Provence (Sud-Est de la France) de la Societe Internationale de Phytosociologie

Conclusions La Provence apparaît, en définitive, comme un territoire des plus variés aux divers points de vue climatique, édaphique, biotique.C'est une région d'autant plus favorable aux études phytosociologiques que la variété des milieux s'y double d'une brutalité souvent étonnante des contrastes, conduisant à la juxtaposition parfois extrêmement précise d'associations végétales très différentes, dont les limites peuvent alors être cartographiquement figurées avec une très suffisante exactitude.Cette vigueur des contrastes est surtout marquée en Provence calcaire où les divers termes des séries évolutives dérivant du Quercetum ilicis climacique ou y conduisant, se juxtaposent souvent sans transition de quelque importance.Les contrastes sont cependant moins accusés en Provence cristalline et dans la Basse-Vallée du Rhône.En Crau comme en Camargue, les associations végétales se juxtaposent souvent en ceintures parallèles ou concentriques — elles s'individualisent alors facilement —, souvent en mosaïques irrégulières, au grè des variations locales des deux facteurs déterminants: l'eau en Crau, le sel en Camargue.En Provence cristalline, les Maures étant surtout faites de roches se délitant facilement (grès, micaschistes et phyllades) sous un climat chaud et humide, le sol se reconstitue facilement après sa destruction partielle par l'érosion; les contrastes sont moins tranchés; on observe des transitions nombreuses entre les divers termes des séries évolutives, dont les limites ne peuvent être fixées qu'approximativement. Nous y avons notamment abordé le problème de la forêt de chêne-liège dont la signification est loin d'être connue, non seulement en Provence mais sur toute l'étendue de son aire, en Afrique du Nord, en Espagne, au Portugal, en France méridionale, en Italie et dans les Iles de la Méditerranée occidentale.En provence cristalline, il est certain que l'homme en a considérablement assuré l'extension, directement pour l'utilisation du liège, indirectement par la coupe et le feu, et, en bien des points de la Méditerranée occidentale, le chêne-liège se présente comme une essence cultivée.Par ailleurs rien ne permet de mettre en doute son indigénat. Mais, dans les conditions actuelles du milieu en Provence cristalline:le chêne vert est possible partout;dans les conditions naturelles de la concurrence vitale le chêne vert l'emporte sur le chêne-liège.Si, donc, la forêt originelle a comporté le chêne-liège, ce ne peut être qu'à l'état d'essence secondaire et seulement en quelques points où une faible couverture forestière lui permettait de cohabiter avec le chêne vert.Les documents cartographiques au I/20 000^e tendent à montrer, d'aileurs que, dans les conditions naturelles de reconstitution de la forêt ou dans le peuplement naturel des sols neufs (Isthme de Giens), c'est la chênaie de chêne vert, non la chênaie de chêne-liège qui s'installe.Les grandes unités phytosociologiques de la Provence paraissent être maintenant convenablement définies floristiquement; il convient donc d'en poursuivre l'étude écologique, dont certains aspects seulement les plus apparents—mais peut-être pas toujours les plus actifs-, ont été abordés.Notons enfin la démonstration faite, au cours de l'excursion, de la parfaite application possible des méthodes phytosociologiques à l'étude des groupements marins et la nécessité, particulièrement apparente en milieu marin, de considérer tout autant les animaux que les végétaux. L'avenir est bien aux biocénoses dont les grands traits ont été mis en évidence, quant à la côte de la presqu'île de Giens, par Roger Molinier.Reçu par la rédaction le 20. XII. 1958.avec la collaboration de ROGER MOLINIER pour la partie marine et G. TALLON pour la Camargue.     

Synergistic effects of ethanol and temperature on yeast mitochondria

At temperatures lower than 37°C, the ethanol inhibition constant (Ki) for growth or fermentation inrho ⁺ cells of theSaccharomyces cerevisiae strain S288C was always higher (1.1M) than inrho ^– mutants (0.7M). At 37°C these differences disappeared, and both strains were equally inhibited by ethanol (Ki=0.7m). Mitochondrial activity can be inhibited by high ethanol concentration and temperature. In fact, the stronger inhibition by ethanol of therho ⁺ strain at 37°C was due to the fact that, under these conditions, this strain loses the advantage conferred by mitochondrial activity since the induction ofrho ^– cells in the population is very high. This does not result in an increase in the frequency ofrho ^– mutants because of the poor viability of these mutants in conditions of high temperature and ethanol. In consequence, S288C strain becomes as strongly inhibited by ethanol as therho ^– mutant strains. Differences in viability were not related to the fatty acids and ergosterol composition of the strain. In the presence of ethanol, bothrho ⁺ andrho ^– strains modified their lipids in the same way, but these changes did not improve their ethanol tolerance. They were not due to differences in adaptation to ethanol either, since after successive transfers in ethanol, growth () and fermentation () rates in therho ^– mutants were increasingly inhibited with time, whereas in the S288C strain inhibition of and by ethanol remained unaltered. Rather,rho ^– mutants are less viable thanrho ⁺ cells because of the inability of the former to respire. At 37°C the Ki increased to 0.9M ethanol either when mitochondrial from highly ethanol-tolerant wine yeasts were transferred torho ^– mutants of the strain S288C or when the mitochondria of strain S288C were preadapted by growing the strain in glycerol instead of glucose before it was cultivated in ethanol.     

Implication of Pectic Components in Cell Surface Interactions between Tomato Root Cells and Fusarium oxysporum f. sp. radicis-lycopersici: A Cytochemical Study by Means of a Lectin with Polygalacturonic Acid-Binding Specificity

Aplysia gonad lectin, a polygalacturonic acid-binding lectin isolated from the sea mollusc Aplysia depilans, was complexed to colloidal gold and used for localizing polygalacturonic-acid-containing molecules in tomato root tissues infected with Fusarium oxysporum f. sp. radicis-lycopersici (FORL). Colonization of host tissues by FORL was associated with striking wall modifications including disruption and even loss of middle lamellae. According to the labeling pattern observed in host wall areas adjacent to fungal penetration channels, it is likely that FORL pectolytic enzymes act through localized wall degradation. The release of polygalacturonic acid-rich wall fragments and the accumulation of polygalacturonic acid-containing molecules in some altered phloem cells were frequently observed and considered to be specific host reactions to fungal attack. The heavy deposition of such molecules at strategic sites such as wall oppositions and intercellular spaces provides support to their implication in the plant defense system. The possible interrelation between polygalacturonic acid-containing molecules and other polymers such as lignin and phenolic compounds remains to be investigated further. The role of these molecules in host-pathogen interactions is discussed in relation to plant defense.