5 resultados para reproductive characters

em DigitalCommons@University of Nebraska - Lincoln


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Forty-four cuticular hydrocarbon components from workers of the termites Nasutitermes corniger (Motschulsky) and N. ephratae (Holmgren) from three localities in Panama were characterized by capillary gas chromatography-electron impact mass spectrometry. Both species contain qualitatively identical homologous series of n-alkanes; 2-, 3-, 11-,13-,14-, and 15-methylalkanes; 11,15-, 12,16-, and 13,17-dimethylalkanes; and 11,15,19- and 13, 17,21-trimethylalkanes. Both species also contain a single alkene, 9-hentriacontene. The two species, however, are readily distinguished chemically by differences among the relative abundances of 11 of their major hydrocarbon components.

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This manuscript provides an overview of past wildlife contraception efforts and discusses the current state of research. Two fertility control agents, an avian reproductive inhibitor containing the active ingredient nicarbazin and an immunocontraceptive vaccine, have received regulatory approval with the Environmental Protection Agency and are commercially available in the USA. OvoControl G Contraceptive Bait for Canada Geese and Ovo Control for pigeons are delivered as oral baits. An injectable immunocontraceptive vaccine (GonaCon Immunocontraceptive Vaccine) was registered with the Environmental Protection Agency for use in female white-tailed deer in September 2009. An injectable product (GonaCon Immunocontraceptive Vaccine) is registered for use in female white-tailed deer. Both products are labeled for use in urban/suburban areas where these species are overabundant. Several other compounds are currently being tested for use in wildlife in the USA, Europe, Australia and New Zealand that could have promise in the future. The development and use of reproductive inhibitors for resolving human–wildlife conflicts will depend on a number of factors, including meeting the requirements of regulatory agencies for use in the environment and on the biological and economical feasibility of their use. Use will also be dependent on health and safety issues and on public acceptance of the techniques.

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Expanding populations of resident Canada geese that remain in suburban and urban areas year-round often result in increased conflicts with humans. Non-lethal and humane means are needed for managing the size of Canada goose flocks residing near or on airports, golf courses, industrial parks, government sites, and city parks. A side effect of nicarbazin, a veterinary drug used to control coccidiosis in chickens, is decreased egg production and hatching. Exploiting this side effect, studies of nicarbazin for reducing the hatchability of eggs from Canada geese were conducted. An initial study in Coturnix quail verified reduction in hatchability in a species other than chickens. Because plasma nicarbazin was not routinely measured, a study in chickens was conducted to determine the relationship between plasma and egg nicarbazin. A comparative study in chickens, mallards, and Canada geese showed that nicarbazin absorption was lowest in geese. Studies in both penned and wild Canada geese showed that reduction in hatchability was possible but neither study used bait suitable for general field application. Bait development led to the OvoControl-G® (Innolytics LLC) bait, which resulted in reduction in hatchability of 51% at treated sites compared to control sites in the field. Previous studies showed that nicarbazin is practically non-toxic and is environmentally friendly; timing and management of baiting will minimize non-target hazards. OvoControl-G® 2500 ppm nicarbazin bait is recommended for incorporation into a comprehensive management plan as a reproductive inhibitor for use in controlling resident Canada goose flock sizes.

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Not more than four species of cestodes of the genus Echinococcus Rudolphi, 1801, are recognized as valid. The larval stage of at least three of them is able to develop in man, causing respective types of hydatid disease. Accurate characterization of these cestodes, including both larval and adult stages, is essential for identification, upon which depends development of methods for preventing infection of man and domestic animals. Because morphological characteristics of the larval cestodes may be modified according to the species of host in which they develop, identification should be based upon taxonomic characters of specimens from the respective natural hosts, which can be identified by means of ecological investigations in endemic areas in combination with controlled infection of experimental animals. The morphological and biological characteristics of the known species are discussed, and the two species most important to public health and economically--E. granulosus (Batsch, 1786) and E. multilocularis Leuckart, 1863--are distinguished. French résumé: Trois espèces de cestodes du genre Echinococcus Rudolphi, 1801 ont été identifiées: E. granulosus (Batsch, 1786); E. multilocularis Leuckart, 1863; et E. oligarthrus (Diesing, 1863). On n'a pas encore déterminé avec certitude s'il fallait leur adjoindre E. patagonicus Szidat, 1960. Ce dernier mis à part, tous ces ténias sont connus pour provoquer chez l'homme des formes spécifiques d'échinococcose hydatique; l'infestation par les larves de E. granulosus est également fréquente chez les ongulés domestiques et la répartition de ce cestode est presque cosmopolite. E. multilocularis est très largement répandu dans l'hémisphère nord, tandis que E. oligarthrus ne se trouve que dans le centre et le sud de I'Amérique. Pour définir des critères morphologiques qui permettent de distinguer avec précision les différentes espèces d'Echinococcus, il convient de prendre les spécimens sur leurs hôtes naturels, sinon l'évolution du stade strobilaire se trouve habituellement retardée et le stade larvaire présente une gamme étendue de variations morphologiques. Pour identifier les hôtes naturels, il faut étudier l'écologie dans les zones d'éndemicité, ainsi que les manifestations de l'infection contrôlée chez des animaux d'expérience. Le stade strobilaire des ténias peut présenter plusieurs caractères spécifiques importants qui concernent notamment la taille, le nombre et la répartition des testicules, la position du pore génital dans les segments gravides, la forme de l'utérus gravide et, dans certains cas, la taille et la forme des crochets du rostre. La structure de la larve normalement développée est caractéristique de chacune des trois espèces relativement bien connues. Les caractéristiques biologiques jouent également un rôle important dans la différenciation de ces cestodes. Au stade larvaire, le laps de temps nécessaire au développement des scolex infectants est directement fonction de la durée de vie de l'hôte intermédiaire. La larve de E. multilocularis présente des scolex infectants dès le deuxième ou le troisième mois, alors qu'ils n'apparaissent qu'au bout d'un ou deux ans chez la larve de E. granulosus. Un tableau donne la liste comparative des caractéristiques taxonomiques qui permettent de faire la distinction entre ces deux espèces.

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The porcine reproductive and respiratory syndrome virus (PRRSV) is an economically important pathogen of swine and is known to cause abortion and infertility in pregnant sows and respiratory distress in piglets. PRRSV contains a major glycoprotein (GP5) and three minor glycoproteins (GP2a, GP3, and GP4) on the virion envelope, all of which are required for infectious virus production. To study their interactions amongst each other and with a cellular receptor for PRRSV, CD163, I cloned each of the viral glycoproteins and CD163 in various expression vectors. My studies have shown that while the GP2a, GP3, and GP4 are co-translationally glycosylated, the GP5 is post-translationally glycosylated. By using co-immunoprecipitation (co-IP) assays, strong interaction was demonstrated between GP4 and GP5 proteins, although weak interactions among the other envelope glycoproteins were also detected. Further, GP4 was found to mediate interactions leading to formation of multiprotein glycoprotein complex. My results also show that GP2a and GP4 proteins are the only two GPs that specifically interact with the CD163 molecule and that glycosylation of these GPs is required for efficient interaction. Based on these studies, I have developed an interactome map of the viral GPs and CD163 and have proposed a model of the viral glycoprotein complex and its interaction with CD163. Studies reported here also show that glycan addition at residue 184 (N184) of GP2a, and residues N42, N50, and N131 of GP3 is essential for recovery of infectious virus. Although single site glycosylation mutants of GP4 had no effect on infectious virus production, introduction of double mutations was lethal. The loss of glycan moieties of GP2a, GP3, and GP4 proteins had no effect on host neutralizing antibody production. Overall, I conclude that the PRRSV glycoproteins are co-translationally and post-translationally glycosylated, the GP4 protein is central to mediating interglycoprotein interactions, and along with GP2a, serves as the viral attachment protein that is responsible for interactions with the viral receptor, CD163. Further, glycosylation of GP2a, GP3, and GP4 proteins is required for infectious virus production, efficient interaction with CD163, but does not play any role in neutralizing antibody response in infected animals.