La division de la cellule phénomène bipolaire de caractère électro-colloÏdal

Sans résumé     

Considérations à proposdes caractères mycologiques et pathogéniques du Keratinomyces ajelloi — Vanbreuseghem 1952, saprophyte du sol

Summary The authors report, for the first time in Rumania, the presence in the soil ofKeratinomyces ajelloi —Vanbreuseghem 1952, isolated by them on 3 different places at Bucharest. One of the isolated strains showed a little more abundant microscopical morphology than the strain first isolated byVanbreuseghem, for it had also coils and chlamydospores.Although this new dermatophyte has been considered, up to now, nonpathogenic for man and animal, the authors were able to obtain positive results in white mice, guinea pig and in man, inoculating repeatedly one of the isolated strains. The experimental lesion it produced, of herpes circinatus type, disappeared in a few days.As the authors conclude, it is not necessary to create a new genus for this dermatophyte. Considering its microscopical aspect, its pathogenicity and its soil origin, they propose to classifyKeratinomyces ajelloi in the genusEpidermophyton —Ota etLangeron 1923 —, giving it the name ofEpidermophyton terrigenum.

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Résumé Les auteurs ont signalé, pour la première fois en Roumanie (à Bucarest), la présence dans les couches superficielles du sol duKeratinomyces ajelloi —Vanbreuseghem 1952. La morphologie microscopique de l'une des deux souches, étudiées de ce point de vue, était un peu plus riche que celle de la souche isolée, pour la première fois parVanbreuseghem car, outre les macroconidies, on y trouvait des vrilles serrées et des chlamydospores. D'autre part, chez les deux souches, les extrémités libres des macroconidies n'étaient pas constament amincies et, par places, plutôt arrondies. L'une des souches s'est montrée pathogène pour l'homme, le cobaye et la souris blanche, chez lesquels son inoculation experimentale a provoqué une mycose superficielle authentique, bien que passagère. Ce caractère n'a pas été signalé jusqu'à présent. Vue sa morphologie microscopique, sa pathogénité et son origine tellurique, les auteurs proposent, pour cette espèce, le nom d'Epidermophyton terrigenum.

     

Rôle du pore basal dans la germination du glomérule de Betterave sucrière

Anatomical analysis of the sugar-beet seed ball indicates two possible ways for the entrance of water and oxygen during germination: cells from the operculum periphery and cells from the basal pore characterized by absence of lignin and a thin layer of cellulose. Impermeabilisation of these zones by vaseline considerably reduces the percentage of germination and stresses the major role played by the basal pore. This can also be confirmed by variation in the germination percentage when sowing the seed ball with the basal pore up or down to the substrate.     

Endémie bilharzienne à Schistosoma mansoni à la vallée du Kou : caractérisation du système de transmission et impact socioéconomique

Schistosomiasis is one of the waterborne diseases which benefit from environmental and behavioral changes induced by the mobilization of surface water resources in Sahelian countries, such as Burkina Faso. Studies have established the existence of human schistosomiasis in the Kou valley, one of the oldest hydro-agricultural zones in the country. However, the role of population behavior in the transmission pattern of this disease and its socioeconomic impact in this valley are poorly understood. It is in response to these questions that this study was undertaken. The objectives of this study were to identify activities that exposed most of the Valley's population to infection by schistosomiasis, and to contribute knowledge on the consequences of this disease. The study was conducted in the cold dry season at the Kou Valley, located in the South Sudanese area of Burkina Faso. It has adopted the strategy of direct observation to examine host–parasites interactions. The study of the socioeconomic consequences of the infection has been first to identify subjects that actually carry the parasite by screening the population by the Kato–Katz method. These were then subjected to a questionnaire. Data were analyzed using Epi Info 6.4. This work has revealed six activities at risk of infection for the residents of the Valley with an increased risk of factor for rice farming, household activities and swimming. In view of these activities, women and young people seem to be most vulnerable to infection. This disease causes significant economic losses as a function of socio-professional categories of infected persons.     

Proteomics in Ménière disease

Ménière's disease (MD) is a disorder of the inner ear characterized by an insidious onset and aspecific symptoms, such as dizziness, vertigo, tinnitus, and hearing loss, that may become very debilitating. The presence of endolymphatic hydrops is a common feature in MD patients, but the pathophysiology is still largely unknown. In this study, we have used a proteomics‐driven approach to identify potential biomarkers of MD. To this end, plasma was obtained from whole blood of 16 individuals previously diagnosed as suffering from MD and compared to plasma from healthy donors. A depletion of the highly abundant proteins (i.e., albumin, IgG, transferrin, etc.) was performed in order to enhance the chance of detection of the less represented ones, therefore reducing the noise‐background. Two‐dimensional gel electrophoresis, followed by in‐gel tryptic digestion of the selected spots and LC‐MS/MS analysis, allowed us to identify a set of proteins whose expression appears to be differentially modulated in patients versus controls. In particular: complement factor H and B, fibrinogen alpha and gamma chains, beta‐actin and pigment epithelium derived factor are over expressed; on the other hand, the levels of beta‐2 glycoprotein‐1, vitamin D binding protein and apolipoprotein‐1 are significantly decreased in the plasma of MD‐affected individuals. Even though preliminary and not necessarily linked directly to the molecular pathogenesis of the disease, our original findings suggest that a molecular signature, represented by the plasma protein profile previously described, might represent a potentially powerful, innovative and not invasive tool for early diagnosis and clinical management of MD patients. J. Cell. Physiol. 227: 308–312, 2012. © 2011 Wiley Periodicals, Inc.     

Signification paléoécologique et paléogéographique des bivalves du Carbonifère inférieur du bassin d’Ancenis (Massif armoricain)

Palaeoecological and palaeogeographical inferences from Early Carboniferous bivalves of the Ancenis Basin (Variscan belt, France). In the basal part of the Ancenis Formation, of Dinantian age, greenish to purple mudstones display a few bivalves, assigned to the genera Lithophaga, Modiolus, and Naiadites. Because Naiadites is considered to be a non-marine bivalve, and is only previously reported in Scotland in Dinantian rocks, a brackish environment can be assumed for the Ancenis Basin during the Early Carboniferous. To cite this article: M. Ballèvre, H. Lardeux, C. R. Palevol 4 (2005).     

Cinétique et caractérisation du phénomène “apoptosis-like” induit au cours de la congélation des spermatozoïdes bovins

Cryopreservation of ejaculated bovine spermatozoa induces severe cell death. In a preliminary study, we observed that cryopreservation and/or thawing was also associated with early apoptotic features in living spermatozoa: i) decrease of the mitochondrial membrane potential^αψm), ii) caspase activation, iii) increase of membrane permeability, without the appearance of late characteristics: iv) no DNA fragmentation. This process has been called “apoptosis-like”. In this study, we evaluated the consequences of each step of cryopreservation of bovine spermatozoa: dilution in cryopreservation medium, equilibration and cryopreservation in liquid nitrogen/thawing. Apoptosis and acrosomal reaction were analysed by flow cytometry and the presence of AIF (Apoptosis Inducing Factor) was analysed by western blot. We observed that dilution in cryopreservation medium induced a marked and immediate increase of the proportion of living spermatozoa with a low^Δψm. After equilibration, the proportion of living spermatozoa with active caspases then began to increase. After the complete cryopreservation/thawing process, this population reached a maximum, and a significant increase of membrane permeability was observed. These results, showing that some features of the “apoptosis-like” phenomenon are initiated in the early steps of cryopreservation, suggest that ice formation may not be the only factor affecting spermatozoa. The consequence of this^Δψm decrease could be the release and/or activation of various pro-apoptotic factors in the cytoplasm. Presence of the pro-apoptotic AIF factor in bovine spermatozoa suggests a possible role of this protein during the cryopreservation process. We also confirmed that cryopreservation of bovine spermatozoa induced an acrosomal reaction. It would be of interest to investigate the relationship between this acrosomal reaction and membrane permeability. A better understanding of the cellular mechanisms involved in sperm cryopreservation would help to improve the preservation of bovine sperm.