Plan d’actions contre la Drosophila suzukii : vignoble

L'objet premier du projet est la protection durable des végétaux contre les bioagresseurs invasifs dans les vergers et les vignes dans le Rhin supérieur. Le point fort est la Drosophila suzukii. Le projet revêt une importance particulière: les petites parcelles des vignobles et des vergers avec leurs structures accompagnantes sont typiques pour la région du Rhin supérieur. Elles abritent une grande diversité d'espèces de flore et faune, mais aussi fournissent des abris et de la nourriture aux espèces invasives. De plus, la région se caractérise par un climat chaud qui convient bien à ces bioagresseurs invasifs qui ne connaissent pas les frontières. La coopération transfrontalière est donc essentielle pour atteindre les objectifs fixés. Partenaires: Landwirtschaftliches Technologiezentrum Augustenberg (LTZ), Dienstleistungszentrum Ländlicher Raum (DLR) Rheinpfalz, Julius-Kühn Institut, Bundesforschungsinstitut für Kulturpflanzen (JKI), RLP Agroscience (RLP), Staatliches Weinbauinstitut Freiburg (WBI), Zentralstelle der Länder für EDV-gestützte Entscheidungshilfen und Programme im Pflanzenschutz (ZEPP), Association de verger expérimental d'Alsace (VEREXAL), Chambre d'agriculture Alsace (CAA), Chambre régionale d'agriculture Grand Est (GRAGE), Conseil Interprofessional des Vins d'Alsace (CIVA), Fédération régionale défense contre les organismes nuisibles an Alsace (FREDON Alsace), Institut National de la Recherche Agronomique (INRA), Institute Français de la Vigne et du Vin (IFV), Bildungszentrum Wallierhof, Forschungsinstitut für biologischen Landbau (FiBL), Landwirtschaftliches Zentrum Ebenrain (LZE), Landwirtschaftliches Zentrum Liebegg (LZL

Grands troncs et petites mouches – Cerisiers haute-tige en difficulté

Déjà difficile en soi, la production de cerises en vergers haute-tige est actuellement menacée pas la drosophile du cerisier. Les arbres sont en effet considérés comme des nids d’infection et leur abattage est exigé en maints endroits

Drosophila suzukii – Un nouveau ravageur des fruits à chair tendre

La drosophile du cerisier Drosophila suzukii a été introduite en Europe en 2008 et a déjà causé de gros dégâts dans le bassin méditerranéen. Ce nouveau ravageur a été identifié en Suisse pour la première fois au cours de l’été passé. Cette drosophile s’attaque à tous les fruits à chair tendre (baies, cerises, raisins) et à de nombreux fruits sauvages. Cette année, toutes les cultures sensibles doivent être surveillées avec des pièges au vinaigre de pomme. Pour la prévention des attaques, il est recommandé d’utiliser des filets à mailles fines, de faire des piégeages de masse et de détruire les fruits attaqués. L’OFAG a autorisé sous conditions l’utilisation de Spinosad et de pyrèthre

Geographical changes in relative frequency of inversions in chromosome III of Drosophila pseudoobscura among natural populations from Mexico

Chromosomal polymorphism in natural populations of Drosophila pseudoobscura have been broadly studied in the USA but scarcely in Mexico where only about 60 localities have been analyzed. Differences among both regions are notorious with respect to their chromosomal constitution. Northern populations, those of USA, have as representative inversions the sequences ST, AR and CH contrasting with those in Southern populations (Mexico) in which prevail the gene arrangements TL, CU and SC. Assuming as a probable mechanism that has allowed these substitutions the flow generated by the presence of a North - South clines, we took as a goal find out if such clines really exist. With that objective in mind we studied 29 populations of this species distributed along four North - South transects. Specimens of D. pseudoobscura caught by attracting them with fermenting bananas were carried to the laboratory where from each female an isofemale line was established. When their offspring appeared a single larva from each isofemale was taken, its salivary glands extracted and stained with a solution of lacto-aceto- orcein, by these means the polytene chromosomes were obtained. On these chromosomes we identified, for each larva, the inversion (s) carried in the third chromosome, in such a way 3439 third chromosomes were analyzed. Among the 29 localities we identified 17 different inversions but the number of them varied from population to population from three to eleven. Relative frequencies of each inversion at every location were calculated and with them for each transect the presence or absence of clines was determined. Among each transect the existence of clines was observed only between two or three near by populations, but we were not able to find a clear manifestation of the presence of clines along a complete transect. Our results at this respect are similar to those previously reported for USA populations. A mechanism that explains North - South substitutions of predominant inversions remains as open question

Microscopies multiharmoniques pour l'imagerie structurale de tissus intacts [Second- and third-harmonic generation microscopies for the structural imaging of intact tissues]

International audienceDepuis son introduction en 1990, la microscopie de fluorescence excitée à deux photons (Fluo-2P) s'est peu à peu imposée comme une méthode incontournable d'imagerie de tissus intacts à l'échelle sub-cellulaire. En effet, la caractéristique la plus remarquable de la microscopie multiphotonique est de maintenir une résolution tridimensionnelle micrométrique lors de l'observation en profondeur d'un milieu optiquement diffusant. Combinée aux technologies de protéines-fusion (type GFP), cette approche est aujourd'hui utilisée dans de nombreux domaines, notamment en neurophysiologie. Un autre attrait de ce type d'imagerie réside dans l'utilisation possible d'autres phénomènes optiques non linéaires (c'est-à-dire impliquant l'interaction simultanée de plusieurs photons avec une molécule observée) comme source de contraste. Ainsi, les microscopies par génération de second harmonique (GSH) et par génération de troisième harmonique (GTH) permettent également d'observer des milieux complexes et fournissent des informations complémentaires par rapport à l'imagerie de fluorescence. Certaines structures cellulaires ou tissulaires fournissent, en effet, ce type de réponse optique sans nécessiter de marquage exogène. La microscopie GSH permet, par exemple, de détecter le collagène fibrillaire et la microscopie GTH permet d'observer sans marquage le développement embryonnaire de petits organismes. One principal advantage of multiphoton excitation microscopy is that it preserves its three-dimensional micrometer resolution when imaging inside light-scattering samples. For that reason two-photon-excited fluorescence microscopy has become an invaluable tool for cellular imaging in intact tissue, with applications in many fields of physiology. This success has driven increasing interest in other forms of nonlinear microscopy that can provide additional information on cells and tissues, such as second- (SHG) and third- (THG) harmonic generation microscopies. In recent years, significant progress has been made in understanding the contrast mechanisms of these recent methodologies, and high-resolution imaging based on intrinsic sources of signal has been demonstrated in cells and tissues. Harmonic generation exhibits structural rather than chemical specificity and can be obtained from a variety of non-fluorescent samples. SHG is observed specifically in dense, non-centrosymmetric arrangements of polarizable molecules, such as collagen fibrils, myofilaments, and polarized microtubule bundles. SHG imaging is therefore emerging as a novel approach for studying processes such as the physiopathological remodelling of the collagen matrix and myofibrillogenesis in intact tissue. THG does not require a non-centrosymmetric system; however no signal can be obtained from a homogeneous medium. THG imaging therefore provides maps of sub-micrometer heterogeneities (interfaces, inclusions) in unstained samples, and can be used as a general purpose structural imaging tool. Recent studies showed that this technique can be used to image embryo development in small organisms and to characterize the accumulation of large lipid bodies in specialized cells. SHG and THG microscopy both rely on femtosecond laser technology and are easily combined with two-photon microscopy

Neurobiological basis of sexual orientation

Iako je spolna orijentacija ljudske populacije varijabilna, većina ljudi prednost daje suprotnom spolu (heteroseksualna orijentacija). Postoji tek manjina koja pokazuje homoseksualnu orijentaciju. Dugo se godina glavno objašnjenje homoseksualnosti temeljilo na utjecaju psiholoških faktora. Danas postoji nešto drugačije shvaćanje homoseksualnosti. Jedna od teorija smatra da je homoseksualnost zapisana u genima. Istraživanja provedena na braći, uključujući i blizance, dokazala su da genetski čimbenik igra ulogu u muškoj, ali i ne ženskoj homoseksualnosti. Homoseksualnost vjerojatno ide ženskom linijom, pošto muškarci primaju svoj jedini X kromosom od majke, pa svako svojstvo koje je vezano uz X kromosom prenosi se sa majki na sinove u svakoj sljedećoj generaciji. Glavni ishod istraživanja je pronalazak povezanosti između homoseksualne orijentacije i markera u regiji Xq28 na X kromosomu. No, naknadno su neki znanstvenici otkrili određene nepravilnosti u toj teoriji. Osim te teorije, postoji i ona o povezanosti utjecaja hormona i spolne orijentacije. Najprije je na životinjskim modelima, a kasnije i na ljudima pokazano da androgeni steroidi koji djeluju prije rođenja mogu utjecati na spolnu orijentaciju odraslih ljudi. Postoje brojni nalazi koji pokazuju da je kod nekih vrsta aromatizacija (pretvorba testosterona u estradiol) kritični korak za maskulinizaciju mozga testosteronom. S obzirom da hormoni u perinatalnom razvoju utječu na razvoj mozga, oni također utječu i na razvoj ponašanja. Perinatalna kastracija mužjaka štakora i primjena testosterona na ženke uzrokovala je preferenciju istog spola. Iako je malo dokaza postoje neke naznake da perinatalni hormoni utječu i na seksualnu orijentaciju kod ljudi. Prema trećoj teoriji, mozgovi homoseksualaca i heteroseksualaca strukturno se razlikuju. Razlike se očituju u veličini treće intersticijske jezgre hipotalamusa, veličini suprahijazmatske jezgre te prednje komisure. Nakon različitih mišljenja o nastanku i uzrocima homoseksualnosti, znanstvenici su pokazali da je homoseksualnost orijentacija koja je nepromjenjiva. Ona nije izbor.Although sexual orientation of the human population is variable, most people give priority to the opposite sex (heterosexual orientation). There are only a minority of people who show homosexual orientation. For many years psychological factors were hold responsive for homosexuality. Understanding of homosexuality is today somewhat different. One of the theories believes that homosexuality is influenced by genes. Researches that were conducted on brothers, including twins, have proved that genetic factors play a role in male but not in female homosexuality. Homosexuality is probably transmitted across female line. Since males receive their single X chromosome exclusively from their mothers, any trait that is influenced by an X-linked gene will be preferentially passed through the mother’s side of the family. The main outcome of the research is finding of link between homosexual orientation and markers in the Xq28 region on the X chromosome. But later, some scientists have discovered certain irregularities in the theory. In addition to these theories, there is one suggested a connection between influence of hormones and sexual orientation. The influence of prenatal androgen steroids on the sexual orientation of adults was demonstrated first on animal models, and later in humans. Numerous findings indicate that in some species, aromatization (conversion of testosterone to estradiol) is a critical step for brain masculinization with testosterone. Since hormones dump the prenatal development affect brain development, they also affect the development of behavior. Perinatal castration of male rats and application of testosterone to females caused a preference for the same sex. There are some indications that perinatal hormones affect sexual orientation in humans, but there is still little evidence to support that. According to the third theory, brains of homosexuals and heterosexuals are structurally different. The differences are reflected in the size of the third interstitial nucleus of hypothalamus, size of suprachiasmatic nucleus and anterior commissure. After various opinions about the origin and causes of homosexuality, scientists have shown that homosexuality is not a choice, but an unchangeable orientation

Identification du gène codant pour l'acétylcholinestérase chez le puceron Aphis gossypii (Glov.)

Le puceron du cotonnier #Aphis gossypii# est un ravageur cosmopolite qui occasionne de sévères dégâts sur de nombreuses plantes cultivées. Les stratégies de lutte sont principalement basées sur l'emploi d'insecticides chimiques tels que les organo-phosphorés et les carbamates qui inhibent l'acétylcholinestérase, enzyme indispensable dans la transmission de l'influx nerveux. Des cas de résistance à ces deux familles d'insecticides ont été recensées depuis quelques années chez #Aphis gossypii# et dont le principal mécanisme est la modificaation de l'acétylcholinestérase par mutation d'un ou plusieurs acides aminés au niveau du site actif de l'enzyme. L'identification des mutations susceptibles d'être impliquées dans la résistance aux insecticides chez le puceron du cotonnier nécessite au préalable l'identification du gène codant pour cette enzym