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161.
The phylogeographic structure of 15 genera of Amazonian marsupials and rodents is summarized based on comparative sequence of the mitochondrial cytochrome b gene. The data are limited in geographical coverage, with samples widely scattered throughout Amazonia from the base of the Andes in Peru to the Guianan coast and eastern Brazil. We use this approach to define species boundaries, based minimally on the principle of reciprocal monophyly, in conjunction with morphological or other genetic discontinuities. The taxa so defined are older than previously appreciated, with many lineages dating from 1 to more than 3 Myr, and thus apparently predating the early Pleistocene. We relate patterns of concordant geographical shifts with underlying tectonic history and to current positions of major rivers. Finally, we provide comments on the utility of these data and patterns to conservation, articulating a need to incorporate phylogeographic information as part of the rationale in establishing conservation priorities at the organismal and geographical area levels. 相似文献
162.
Cell-to-cell and phloem-mediated transport of potato virus X. The role of virions 总被引:13,自引:1,他引:12
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Movement-deficient potato virus X (PVX) mutants tagged with the green fluorescent protein were used to investigate the role of the coat protein (CP) and triple gene block (TGB) proteins in virus movement. Mutants lacking either a functional CP or TGB were restricted to single epidermal cells. Microinjection of dextran probes into cells infected with the mutants showed that an increase in the plasmodesmal size exclusion limit was dependent on one or more of the TGB proteins and was independent of CP. Fluorescently labeled CP that was injected into epidermal cells was confined to the injected cells, showing that the CP lacks an intrinsic transport function. In additional experiments, transgenic plants expressing the PVX CP were used as rootstocks and grafted with nontransformed scions. Inoculation of the PVX CP mutants to the transgenic rootstocks resulted in cell-to-cell and systemic movement within the transgenic tissue. Translocation of the CP mutants into sink leaves of the nontransgenic scions was also observed, but infection was restricted to cells close to major veins. These results indicate that the PVX CP is transported through the phloem, unloads into the vascular tissue, and subsequently is transported between cells during the course of infection. Evidence is presented that PVX uses a novel strategy for cell-to-cell movement involving the transport of filamentous virions through plasmodesmata. 相似文献
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云南西部局限蚊属一新种:(双翅目:蚊科) 总被引:1,自引:0,他引:1
本文报道1989年8月从滇西边陲盈江县那邦河谷地带的野生芭蕉叶腋采获的一新种局限蚊--长鬃局限蚊Topomyia(T.)longisetosa sp.nov.。标本保存于云南省流行病研究所。 相似文献
165.
ELOIZA A.M. DE SOUZA VALÉRIA P.R. MINIM LUIS A. MINIM JANE S.R. COIMBRA RONEY A. DA ROCHA 《Journal of sensory studies》2007,22(2):115-125
The effect of some fresh‐cut carrot label attributes on consumer purchase intention was evaluated using conjoint analysis. The following three attributes were chosen and manipulated: price (high and low), packaging type (polyethylene bags and expanded polystyrene trays) and production process (organic with certification stamp, organic without certification stamp and no information). A complete factorial design was used, and 12 hypothetical packages of fresh‐cut carrot were developed and evaluated by 96 consumers based on their purchase intention. The consumers were divided into four groups with different opinions. Low price and organic with certification label were the favorite choices of the groups. Only one group preferred expanded polystyrene trays. No interactions were exhibited among the attributes in all groups. 相似文献
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CHRISTIAN KLUG BJ
RN KR
GER WOLFGANG KIESSLING GARY L. MULLINS THOMAS SERVAIS JIÍ FRÝDA DIETER KORN SUSAN TURNER 《Lethaia: An International Journal of Palaeontology and Stratigraphy》2010,43(4):465-477
Klug, C., Kröger, B., Kiessling, W., Mullins, G.L., Servais, T., Frýda, J., Korn, D. & Turner, S. 2009: The Devonian nekton revolution. Lethaia, 10.1111/j.1502‐3931.2009.00206.x Traditional analyses of Early Phanerozoic marine diversity at the genus level show an explosive radiation of marine life until the Late Ordovician, followed by a phase of erratic decline continuing until the end of the Palaeozoic, whereas a more recent analysis extends the duration of this early radiation into the Devonian. This catch‐all approach hides an evolutionary and ecological key event long after the Ordovician radiation: the rapid occupation of the free water column by animals during the Devonian. Here, we explore the timing of the occupation of the water column in the Palaeozoic and test the hypothesis that ecological escalation led to fundamental evolutionary changes in the mid‐Palaeozoic marine water column. According to our analyses, demersal and nektonic modes of life were probably initially driven by competition in the diversity‐saturated benthic habitats together with the availability of abundant planktonic food. Escalatory feedback then promoted the rapid rise of nekton in the Devonian as suggested by the sequence and tempo of water‐column occupation. □Devonian, diversity, ecology, food webs, nekton, plankton, radiation. 相似文献
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FERNANDO STEELE DA CRUZ STUART M. KRASSNER 《The Journal of eukaryotic microbiology》1971,18(4):718-722
SYNOPSIS. Continuous growth of one cell line (UCI variant) of Leishmania tarentolae was achieved in the absence of organic sulfur. These cells were able to use sodium sulfate, and, to a limited extent, sodium sulfite as their sole sulfur source and could utilize methionine sulfoxide in place of L-methionine. A related cell line (RU variant) was unable to grow in organic sulfate-free media nor could these cells utilize methionine sulfoxide. UCI promastigotes incorporated significant amounts of 35S sodium sulfate; killed cells did not take up the label. 35S incorporation was inhibited by sodium molybdate (5 × 10?4 M), sodium arsenite (5 × 10?4 M), 2,4-dinitrophenol (1 × 10?4 M), or KCN (5 × 10?4 M). RU promastigotes did not incorporate significant amounts of 35S sodium sulfate. Thin layer chromatographs of protein hydrolysates from UCI cells incubated in 35S sodium sulfate revealed several radio opaque spots, one of which had chromatographic properties of cystine. UCI variants of L. tarentolae were therefore capable of assimilatory sulfate reduction whereas RU cells lacked this ability. 相似文献
170.