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David W. Langor John R. Spence Greg R. Pohl 《Evolution; international journal of organic evolution》1990,44(3):609-618
Mountain pine beetles from lodgepole and limber pine in western Canada were crossbred. We compared data about reproductive success and fecundity of parents as well as development, mortality, and fertility of their progeny to determine whether there was reproductive isolation among beetle populations in these hosts. Three factors, directly or indirectly related to the host, influenced reproductive performance of parents (reproductive success, egg gallery length, fecundity, and number of eggs laid per centimeter of gallery) as well as the mortality, dry weight, and fat content of the progeny: (1) the host species in which progeny were reared, (2) the host species in which the female parent was reared, and (3) whether both parents originated from the same or different host species. Limber pine appears to be a better host for Dendroctonus ponderosae reproduction and survival than lodgepole pine. Nonetheless, beetles reared from lodgepole and limber pine can reproduce in either host and will mate with each other. Progeny of all crosses were fertile. Thus, there is no apparent barrier to prevent beetles from the two host species from interbreeding in the field. 相似文献
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Jan Klimaszewski Reginald P. Webster David W. Langor Caroline Bourdon H.E. James Hammond Greg R. Pohl Benoit Godin 《ZooKeys》2014,(412):9-40
Four species of Gnathusa Fenyes (G. alfacaribou Klimaszewski & Langor, G. caribou Lohse, G. eva Fenyes, and G. tenuicornis Fenyes) occur in the Nearctic and in Canada. Three species of Ocyusa Kraatz (O. asperula Casey, O. californica Bernhauer, O. canadensis Lohse), and three species of Mniusa Mulsant and Ray (M. minutissima (Klimaszewski & Langor), M. yukonensis (Klimaszewski & Godin), and M. odelli Klimaszewski & Webster, sp. n.), are known from the Nearctic and all but O. californica occur in Canada. The recently described Gnathusa minutissima Klimaszewski and Langor and Ocyusa yukonensis Klimaszewski and Godin, are transferred here to the genus Mniusa Mulsant & Rey. New provincial and state records are reported for: G. eva (Alberta), G. tenuicornis (Alberta, Oregon, and New Brunswick), O. canadensis (New Brunswick and Newfoundland), M. minutissima (New Brunswick), and M. yukonensis (Nova Scotia, New Brunswick, Quebec, and British Columbia). The female of M. yukonensis was discovered and is illustrated for the first time. The genus Mniusa is reported for the first time from Canada and represents the first confirmed generic record for North America. Keys for identification of all Canadian species, images of body and genital structures, maps showing distribution mainly in Canada, and new bionomics data are provided. 相似文献
4.
Current status of antisense DNA methods in behavioral studies 总被引:4,自引:0,他引:4
The antisense DNA method has been used successfully to block the expression
of specific genes in vivo in neuronal systems. An increasing number of
studies in the last few years have shown that antisense DNA administered
directly into the brain can modify various kinds of behaviors. These
findings strongly suggest that the antisense DNA method can be used as a
powerful tool to study causal relationships between molecular processes in
the brain and behavior. In this article we review the current status of the
antisense method in behavioral studies and discuss its potentials and
problems by focusing on the following four aspects; (i) optimal application
paradigms of antisense DNA methods in behavioral studies; (ii) efficiencies
of different administration methods of antisense DNA used in behavioral
studies; (iii) determination of specificity of behavioral effects of
antisense DNA; and (iv) discrepancies between antisense DNA effects on
behaviors and those on protein levels of the targeted gene.
相似文献
5.
Paul DW Kirk Aviva Witkover Alan Courtney Alexandra M Lewin Robin Wait Michael PH Stumpf Sylvia Richardson Graham P Taylor Charles RM Bangham 《Retrovirology》2011,8(1):1-9
Background
A new subgroup of HIV-1, designated Group P, was recently detected in two unrelated patients of Cameroonian origin. HIV-1 Group P phylogenetically clusters with SIVgor suggesting that it is the result of a cross-species transmission from gorillas. Until today, HIV-1 Group P has only been detected in two patients, and its degree of adaptation to the human host is largely unknown. Previous data have shown that pandemic HIV-1 Group M, but not non-pandemic Group O or rare Group N viruses, efficiently antagonize the human orthologue of the restriction factor tetherin (BST-2, HM1.24, CD317) suggesting that primate lentiviruses may have to gain anti-tetherin activity for efficient spread in the human population. Thus far, three SIV/HIV gene products (vpu, nef and env) are known to have the potential to counteract primate tetherin proteins, often in a species-specific manner. Here, we examined how long Group P may have been circulating in humans and determined its capability to antagonize human tetherin as an indicator of adaptation to humans.Results
Our data suggest that HIV-1 Group P entered the human population between 1845 and 1989. Vpu, Env and Nef proteins from both Group P viruses failed to counteract human or gorilla tetherin to promote efficient release of HIV-1 virions, although both Group P Nef proteins moderately downmodulated gorilla tetherin from the cell surface. Notably, Vpu, Env and Nef alleles from the two HIV-1 P strains were all able to reduce CD4 cell surface expression.Conclusions
Our analyses of the two reported HIV-1 Group P viruses suggest that zoonosis occurred in the last 170 years and further support that pandemic HIV-1 Group M strains are better adapted to humans than non-pandemic or rare Group O, N and P viruses. The inability to antagonize human tetherin may potentially explain the limited spread of HIV-1 Group P in the human population. 相似文献6.
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L-Lactate dehydrogenase (L-LDH, E.C. 1.1.1.27) is encoded by two or three
loci in all vertebrates examined, with the exception of lampreys, which
have a single LDH locus. Biochemical characterizations of LDH proteins have
suggested that a gene duplication early in vertebrate evolution gave rise
to Ldh-A and Ldh-B and that an additional locus, Ldh-C arose in a number of
lineages more recently. Although some phylogenetic studies of LDH protein
sequences have supported this pattern of gene duplication, others have
contradicted it. In particular, a number of studies have suggested that
Ldh-C represents the earliest divergence among vertebrate LDHs and that it
may have diverged from the other loci well before the origin of
vertebrates. Such hypotheses make explicit statements about the
relationship of vertebrate and invertebrate LDHs, but to date, no closely
related invertebrate LDH sequences have been available for comparison. We
have attempted to provide further data on the timing of gene duplications
leading to multiple vertebrate LDHs by determining the cDNA sequence of the
LDH of the tunicate Styela plicata. Phylogenetic analyses of this and other
LDH sequences provide strong support for the duplications giving rise to
multiple vertebrate LDHs having occurred after vertebrates diverged from
tunicates. The timing of these LDH duplications is consistent with data
from a number of other gene families suggesting widespread gene duplication
near the origin of vertebrates. With respect to the relationships among
vertebrate LDHs, our data are not consistent with previous claims that
Ldh-C represented the earliest divergence. However, the precise
relationships among some of the main lineages of vertebrate LDHs were not
resolved in our analyses.
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8.
Logging is the main human disturbance in the boreal forest; thus, understanding the effects of harvesting practices on biodiversity is essential for a more sustainable forestry. To assess changes in spider composition because of harvesting, samples were collected from three forest layers (overstory, understory, and ground) of deciduous and conifer dominated stands in the northwestern Canadian boreal mixedwood forest. Spider assemblages and feeding guild composition were compared between uncut controls and stands harvested to 20% retention. In total, 143 spider species were collected, 74 from the ground, 60 from the understory, and 71 from the overstory, and species composition of these three pools differed considerably among layers. Distinctive spider assemblages were collected from the canopy of each forest cover type but these were only slightly affected by harvesting. However, logging had a greater impact on the species composition in the understory and ground layers when compared with unharvested controls. Guild structure differed among layers, with wandering and sheet-weaving spiders dominant on the ground while orb-weaving and ambush spiders were better represented in the understory and overstory, respectively. Given the ecological importance of spiders and the expectation of faunal changes with increased harvesting, further efforts toward the understanding of species composition in higher strata of the boreal forest are needed. 相似文献
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David W. Langor 《BioControl》1991,36(2):303-313
Fifty-four species of insects, 5 of spiders, 5 of mites, 1 harvestman and 1 nematode co-occurred with the eastern larch beetle,Dendroctonus simplex LeConte, on tamarack,Larix laricina (Du Roi) K. Koch, at 2 localities in Newfoundland. The most abundant predators were the flyMedetera gaspensis Bickel and the beetleRhizophagus dimidiatus Mannerheim and the most abundant parasitoids were the HymenopteraSpathius canadensis Ashmead,Rhopalicus tutela (Walker) andRoptrocerus xylophagorum (Ratzburg).D. simplex is recorded as a new host for 9 predator and 3 parasitoid species.
相似文献
10.
Jan Klimaszewski Reginald P. Webster Caroline Bourdon Georges Pelletier Benoit Godin David W. Langor 《ZooKeys》2015,(487):111-139
Six species of the genus Mocyta Mulsant & Rey are reported from Canada: Mocyta
amblystegii (Brundin), Mocyta
breviuscula (Mäklin), Mocyta
discreta (Casey), Mocyta
fungi (Gravenhorst), Mocyta
luteola (Erichson), and Mocyta
sphagnorum Klimaszewski & Webster, sp. n. New provincial and state records include: Mocyta
breviuscula – Saskatchewan and Oregon; Mocyta
discreta – Quebec, Ontario and Saskatchewan; Mocyta
luteola – New Brunswick, Quebec, Ontario, Massachusetts and Minnesota; and Mocyta
fungi – Saskatchewan. Mocyta
sphagnorum is described from eastern Canada from specimens captured in Newfoundland, New Brunswick, Quebec and Ontario. Mocyta
negligens Mulsant and Rey, a native European species suspected of occurring in Canada, is excluded from the Nearctic fauna based on comparison of European types with similarly coloured Canadian specimens, which are now identified as Mocyta
luteola. The European species, Mocyta
gilvicollis (Scheerpeltz), is synonymized with another European nominal species, Mocyta
negligens, based on examination of type material of the two species. Lectotypes are designated for Eurypronota
discreta Casey, Atheta
gilvicollis Scheerpeltz, Homalota
luteola Erichson, Colpodota
negligens Mulsant and Rey, Acrotona
prudens Casey and Dolosota
redundans Casey. The latter species is here synonymized with Mocyta
luteola. A review of the six Nearctic species is provided, including keys to species and closely related genera, colour habitus images, images of genitalia, biological information and maps of their distributions in Canada. 相似文献