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11.
Sheep prions with molecular properties intermediate between classical scrapie,BSE and CH1641–scrapie
Jan PM Langeveld Jorg G Jacobs Jo HF Erkens Thierry Baron Olivier Andréoletti Takahashi Yokoyama 《朊病毒》2014,8(4):296-305
Efforts to differentiate bovine spongiform encephalopathy (BSE) from scrapie in prion infected sheep have resulted in effective methods to decide about the absence of BSE. In rare instances uncertainties remain due to assumptions that BSE, classical scrapie and CH1641–a rare scrapie variant–could occur as mixtures. In field samples including those from fallen stock, triplex Western blotting analyses of variations in the molecular properties of the proteinase K resistant part of the disease‑associated form of prion protein (PrPres) represents a powerful tool for quick discrimination purposes. In this study we examined 7 deviant ovine field cases of scrapie for some typical molecular aspects of PrPres found in CH1641‑scrapie, classical scrapie and BSE. One case was most close to scrapie with respect to molecular mass of its non-glycosylated fraction and N-terminally located 12B2‑epitope content. Two cases were unlike classical scrapie but too weak to differentiate between BSE or CH1641. The other 4 cases appeared intermediate between scrapie and CH1641 with a reduced molecular mass and 12B2‑epitope content, together with the characteristic presence of a second PrPres population. The existence of these 2 PrPres populations was further confirmed through deglycosylation by PNGaseF. The findings indicate that discriminatory diagnosis between classical scrapie, CH1641 and BSE can remain inconclusive with current biochemical methods. Whether such intermediate cases represent mixtures of TSE strains should be further investigated e.g. in bioassays with rodent lines that are varying in their susceptibility or other techniques suitable for strain typing. 相似文献
12.
Background
The ABCC5 gene encodes an organic anion pump of the ATP-binding cassette (ABC) transporter family, subclass C. The exact physiological function of ABCC5 however is not known. Here, we have isolated three novel ABCC5 splice variants and characterized their role in the regulation of ABCC5 gene expression. 相似文献13.
Borsboom GJ Boatin BA Nagelkerke NJ Agoua H Akpoboua KL Alley EW Bissan Y Renz A Yameogo L Remme JH Habbema JD 《Filaria journal》2003,2(1):8-25
BACKGROUND: The Onchocerciasis Control Program (OCP) in West Africa has been closed down at the end of 2002. All subsequent control will be transferred to the participating countries and will almost entirely be based on periodic mass treatment with ivermectin. This makes the question whether elimination of infection or eradication of onchocerciasis can be achieved using this strategy of critical importance. This study was undertaken to explore this issue. METHODS: An empirical approach was adopted in which a comprehensive analysis was undertaken of available data on the impact of more than a decade of ivermectin treatment on onchocerciasis infection and transmission. Relevant entomological and epidemiological data from 14 river basins in the OCP and one basin in Cameroon were reviewed. Areas were distinguished by frequency of treatment (6-monthly or annually), endemicity level and additional control measures such as vector control. Assessment of results were in terms of epidemiological and entomological parameters, and as a measure of inputs, therapeutic and geographical coverage rates were used. RESULTS: In all of the river basins studied, ivermectin treatment sharply reduced prevalence and intensity of infection. Significant transmission, however, is still ongoing in some basins after 10-12 years of ivermectin treatment. In other basins, transmission may have been interrupted, but this needs to be confirmed by in-depth evaluations. In one mesoendemic basin, where 20 rounds of four-monthly treatment reduced prevalence of infection to levels as low as 2-3%, there was significant recrudescence of infection within a few years after interruption of treatment. CONCLUSIONS: Ivermectin treatment has been very successful in eliminating onchocerciasis as a public health problem. However, the results presented in this paper make it almost certain that repeated ivermectin mass treatment will not lead to the elimination of transmission of onchocerciasis from West Africa. Data on 6-monthly treatments are not sufficient to draw definitive conclusions. 相似文献
14.
Worldwide patterns of mitochondrial DNA differentiation in the harbor seal (Phoca vitulina) 总被引:3,自引:0,他引:3
Stanley HF; Casey S; Carnahan JM; Goodman S; Harwood J; Wayne RK 《Molecular biology and evolution》1996,13(2):368-382
The harbor seal (Phoca vitulina) has one of the broadest geographic
distributions of any pinniped, stretching from the east Baltic, west across
the Atlantic and Pacific Oceans to southern Japan. Although individuals may
travel several hundred kilometers on annual feeding migrations, harbor
seals are generally believed to be philopatric, returning to the same areas
each year to breed. Consequently, seals from different areas are likely to
be genetically differentiated, with levels of genetic divergence increasing
with distance. Differentiation may also be caused by long-standing
topographic barriers such as the polar sea ice. We analyzed samples of 227
harbor seals from 24 localities and defined 34 genotypes based on 435 bp of
control region sequence. Phylogenetic analysis and analysis of molecular
variance showed that populations in the Atlantic and Pacific Oceans and
east and west coast populations of these oceans are significantly
differentiated. Within these four regions, populations that are
geographically farthest apart generally are the most differentiated and
often do not share genotypes or differ in genotype frequency. The average
corrected sequence divergence between populations in the Atlantic and
Pacific Oceans is 3.28% +/- 0.38% and those among populations within each
of these oceans are 0.75% +/- 0.69% and 1.19% +/- 0.65%, respectively. Our
results suggest that harbor seals are regionally philopatric, on the scale
of several hundred kilometers. However, genetic discontinuities may exist,
even between neighboring populations such as those on the Scottish and east
English coasts or the east and west Baltic. The mitochondrial data are
consistent with an ancient isolation of populations in both oceans, due to
the development of polar sea ice. In the Atlantic and Pacific, populations
appear to have been colonized from west to east with the European
populations showing the most recent common ancestry. We suggest the recent
ancestry of European seal populations may reflect recolonization from Ice
Age refugia after the last glaciation.
相似文献
15.
Sletta H Klinkenberg G Winnberg A Kvitvang HF Nilsen MB Krokan HE Otterlei M Bruheim P 《Journal of microbiological methods》2011,87(3):363-367
A high resolution high throughput screening method has been developed for stress response phenotyping of the global Saccharomyces cerevisiae knock out mutant collection. Stress causing agent is added at three concentrations to individual mutant cultures growing in early exponentially phase in 384-well microplates, and the dynamic effect of stress agent exposure is measured by following subsequent growth profiles of individual mutants with a resolution of three optical density measurements per hour. Software was written for calculation of sensitivity coefficients and efficient visual inspection of the growth and inhibition curves. Three DNA damage response causing agents were chosen to explore the feasibility of the new screening method: methyl methanesulphonate, 5-fluorouracil and cisplatin. They were tested in three biological replicas on a 1400 mutant large sub-library of the homozygote diploid S. cerevisiae gene knock out collection. The sub-library consisted of only mutants with a human ortholog to the inactivated gene. Almost 400 mutants were found more sensitive to one or more of the agents. Forty-nine mutants were sensitive to all three agents. One of the mutants, ERK5, sensitive to all three agents was chosen for follow-up human cell experiments to verify that such yeast screens can be used as hypothesis generator for human cell studies. Similar to yeast, HeLa cells became more sensitive against all three DNA damaging agents when co-treated with the ERK5 inhibitor BIX21088, thus supporting the result from the yeast phenotype screen. 相似文献
16.
NA Rivers-Moore HF Dallas FC de Moor J Barendse 《African Journal of Aquatic Science》2018,43(3):215-227
Non-native vegetation in the riparian zone impacts on water temperatures, flow patterns, degree of shading, channel modification, and changes to natural sediment loads. Freshwater ecosystems in the Garden Route Initiative planning domain are of particular conservation value, because of the rich Gondwanaland relict aquatic macroinvertebrate fauna found in the rivers there, which are vulnerable to thermal changes. Data were collected during 2013 and 2014 at 19 sites on seven river systems between George and Knysna in the southern Cape, South Africa. These included 12 months of hourly water temperatures at all sites, and quantitative sampling of aquatic macroinvertebrates at ten sites. Each site was characterised in terms of water quality (pH, conductivity and turbidity) and general characteristics, including impacts such as density of non-native riparian trees. At the family level, aquatic macroinvertebrate communities showed variation between sites and seasons. Differences were more pronounced on the basis of natural land cover type (fynbos versus indigenous forest) than densities of non-native invasive riparian vegetation. Conservation of these river systems will depend on maintaining a mosaic of natural vegetation types. 相似文献
17.
18.
Climate change poses an unprecedented threat to biodiversity worldwide. Consequently, unrecognised taxa may not receive adequate conservation attention to survive. We used molecular and morphological data to address the challenge of species delimitation within the genus Schilbe. The presence or absence of an adipose fin and distribution based on east-flowing, conceivably faster-flowing, or west-flowing, probably more slow-flowing, river systems were considered. Distinctive geographic patterns in genetic variation within southern, eastern, and western African populations were revealed. Particularly, the South African population is distinct from those of Namibia, Botswana and Nigeria. No individuals with rudimentary adipose fins were found at any locality, but specimens from three localities either had or did not have adipose fins. These mixed occurrences are suspected to be a result of human interventions, and that the presence of rudimentary adipose fins in the east African species could be an adaptive feature that serves to stabilise these fish in faster currents. In addition, the genetic divergence observed among African silver catfish from geographically isolated river systems is conceivably the result of micro-evolutionary adaptive responses to different environmental conditions. Collectively, these results distinguish S. depressirostris from S. intermedius. 相似文献
19.
Vladimir M Milenkovic Thomas Langmann Rainer Schreiber Karl Kunzelmann Bernhard HF Weber 《BMC evolutionary biology》2008,8(1):72