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131.
Paul K. Hershberger Bjorn K. van der Leeuw Jacob L. Gregg Courtney A. Grady Kenneth M. Lujan Susan K. Gutenberger Maureen K. Purcell James C. Woodson James R. Winton Michael J. Parsley 《Biological invasions》2010,12(11):3665-3675
The introduction of American shad from the Atlantic to the Pacific coast of North America in the late 1800’s and the subsequent
population expansion in the 1980’s resulted in the amplification of Ichthyophonus sp., a Mesomycetozoean parasite of wild marine fishes. Sequence analysis of the ribosomal DNA gene complex (small subunit
and internal transcribed spacer regions) and Ichthyophonus epidemiological characteristics indicate a low probability that Ichthyophonus was co-introduced with American shad from the Atlantic; rather, Ichthyophonus was likely endemic to marine areas of the Pacific region and amplified by the expanding population of a highly susceptible
host species. The migratory life history of shad resulted in the transport of amplified Ichthyophonus from its endemic region in the NE Pacific to the Columbia River watershed. An Ichthyophonus epizootic occurred among American shad in the Columbia River during 2007, when infection prevalence was 72%, and 57% of the
infections were scored as moderate or heavy intensities. The epizootic occurred near the record peak of shad biomass in the
Columbia River, and corresponded to an influx of 1,595 mt of infected shad tissues into the Columbia River. A high potential
for parasite spillback and the establishment of a freshwater Ichthyophonus life cycle in the Columbia River results from currently elevated infection pressures, broad host range, plasticity in Ichthyophonus life history stages, and precedents for establishment of the parasite in other freshwater systems. The results raise questions
regarding the risk for sympatric salmonids and the role of Ichthyophonus as a population-limiting factor affecting American shad in the Columbia River. 相似文献
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Anahita Z. Mostafavi Donovan K. Lujan Katelyn M. Erickson Christina D. Martinez Jerry M. Troutman 《Bioorganic & medicinal chemistry》2013,21(17):5428-5435
Undecaprenyl Pyrophosphate Synthase (UPPS) is an enzyme critical to the production of complex polysaccharides in bacteria, as it produces the crucial bactoprenol scaffold on which these materials are assembled. Methods to characterize the systems associated with polysaccharide production are non-trivial, in part due to the lack of chemical tools to investigate their assembly. In this report, we develop a new fluorescent tool using UPPS to incorporate a powerful fluorescent anthranilamide moiety into bactoprenol. The activity of this analogue in polysaccharide biosynthesis is then tested with the initiating hexose-1-phosphate transferases involved in Capsular Polysaccharide A biosynthesis in the symbiont Bacteroides fragilis and the asparagine-linked glycosylation system of the pathogenic Campylobacter jejuni. In addition, it is shown that the UPPS used to make this probe is not specific for E-configured isoprenoid substrates and that elongation by UPPS is required for activity with the downstream enzymes. 相似文献