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71.
长春净月潭地区土壤跳虫的生态分布 总被引:8,自引:1,他引:8
土壤动物直接参与土壤形成,它与土壤微生物的相互配合,对植物凋落物的分解起着十分重要的作用。土壤跳虫是土壤动物中最重要的类群之一。关于它的生态分布,目前国内报道不多。东北师范大学和日本九州大学合作,对长春净月潭地区的土壤跳虫进行了初步调查。 相似文献
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Dendritic cells can be rapidly expanded ex vivo and safely administered in patients with metastatic breast cancer 总被引:2,自引:1,他引:2
Dees EC McKinnon KP Kuhns JJ Chwastiak KA Sparks S Myers M Collins EJ Frelinger JA Van Deventer H Collichio F Carey LA Brecher ME Graham M Earp HS Serody JS 《Cancer immunology, immunotherapy : CII》2004,53(9):777-785
Purpose Immunotherapy using either dendritic cells (DCs) or expanded cytotoxic T cells (CTLs) has received increased interest in the treatment of specific malignancies including metastatic breast cancer (MBC). DCs can be generated ex vivo from monocytes or CD34+ precursors. The ability to expand and safely administer CD34-derived DCs in patients with MBC that have received prior cytotoxic chemotherapy has not been evaluated.Methods We enrolled ten patients with MBC that had received prior chemotherapy for the treatment of metastatic disease on a phase I/II trial designed to test the safety and feasibility of administering ex vivo expanded DCs from CD34+ progenitor cells.Results Using a cocktail of multiple different cytokines, we could expand DCs 19-fold compared to the initial CD34-selected product, which allowed the administration of as many as six vaccine treatments per patient. Patients received three to six injections i.v. of DCs pulsed with either the wild type GP2 epitope from the HER-2/neu protein or an altered peptide ligand, isoleucine to leucine (I2L). Toxicity was mild, with no patients demonstrating grade III toxicity during the treatment. Two patients with subcutaneous disease had a partial response to therapy, while IFN--producing CD8+ T cells could be found in two other patients during treatment.Conclusions This approach is safe and effective in generating a significant quantity of DCs from CD34-precursors.Supported in part by Grants CA 58223 and 89961 from the National Cancer Institute, the Breast Cancer Research Foundation, and RR0046 from the General Clinical Research Center program of the Division of Research Resources, National Institutes of Health. 相似文献
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JOSEF BRYJA PETER KAUCH ALENA FORNSKOVÁ TOMÁ BARTONIKA ZDENK EHÁK 《Biological journal of the Linnean Society. Linnean Society of London》2009,96(1):103-114
Although two cryptic pipistrelle bat species, Pipistrellus pipistrellus and Pipistrellus pygmaeus , belong among the most common bat species in Europe, it is still unclear whether they can migrate over long distances between summer and winter roosts. Long-distance migratory species may be expected to show low levels of genetic structuring in large areas due to regular mixing of the gene pool by mating that occurs during migration and/or hibernation. Conversely, the dispersal of gametes in sedentary species is spatially restricted, populations are more genetically structured, and isolation by relatively short distance is visible. By analysing diversity of highly variable microsatellites within and among summer colonies of both studied species in central Europe, we found that differentiation between populations is very weak. Both classical F ST and Bayesian clustering approach failed to detect genetic structure among colonies and there was no significant isolation-by-distance pattern. The analyses of relatedness, however, revealed that individuals within colonies are more related than random suggesting philopatry of at least one sex. The results were very similar for the two species. The high level of gene flow among central European populations, even on large geographic distances, is discussed in relation with migrations, dispersal, and mating behaviour. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 96 , 103–114. 相似文献
76.
RADEK VODRÁKA 《Palaeontology》2009,52(1):187-192
Abstract: A new method for the extraction of calcified and/or partly pyritized macrofossils has been developed. This method is based upon the differential speeds for the dissolving of microcrystalline and macrocrystalline calcite in 38% sulphuric acid. The effectiveness of the sulphuric acid treatment is also influenced by the volume of clay minerals in the host rock. Therefore, this method is highly applicable for the extraction of macrofossils from marlstones, marly limestones, and other lithified calcareous sediments. The main advantages of this method, when compared with other chemical methods, are (1) the short treatment time, (2) the capability of dissolving the sediment on the fossil's surface, and (3) its efficiency in dissolving calcareous rocks with low porosity. This method has been successfully applied to Upper Cretaceous macrofossils from the Bohemian Cretaceous Basin. The surface of extracted macrofossils remained undamaged, exhibiting minute skeletal details; perhaps even encrusters and bioerosions. 相似文献
77.
Multiple interspecies transmissions of human and simian T-cell leukemia/lymphoma virus type I sequences 总被引:8,自引:0,他引:8
Using two sets of nucleotide sequences of the human and simian T-cell
leukemia/lymphoma virus type I (HTLV-I/STLV-I), one consisting of 522 bp of
the env gene from 70 viral strains and the other a 140-bp segment from the
pol gene of 52 viral strains, I estimated cladograms based on a statistical
parsimony procedure that was developed specifically to estimate
within-species gene trees. An extension of a nesting procedure is offered
for sequence data that forms nested clades used in hypothesis testing. The
nested clades were used to test three hypotheses relating to transmission
of HTLV/STLV sequences: (1) Have cross-species transmissions occurred and,
if so, how many? (2) In what direction have they occurred? (3) What are the
geographic relationships of these transmission events? The analyses support
a range of 11-16 cross-species transmissions throughout the history of
these sequences. Additionally, outgroup weights were assigned to haplotypes
using arguments from coalescence theory to infer directionality of
transmission events. Conclusions on geographic origins of transmission
events and particular viral strains are inconclusive due to small samples
and inadequate sampling design. Finally, this approach is compared directly
to results obtained from a traditional maximum parsimony approach and found
to be superior at establishing relationships and identifying instances of
transmission.
相似文献
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80.
The mutation rates of di-, tri- and tetranucleotide repeats in Drosophila melanogaster 总被引:3,自引:1,他引:3
Schug MD; Hutter CM; Wetterstrand KA; Gaudette MS; Mackay TF; Aquadro CF 《Molecular biology and evolution》1998,15(12):1751-1760
In a recent study, we reported that the combined average mutation rate of
10 di-, 6 tri-, and 8 tetranucleotide repeats in Drosophila melanogaster
was 6.3 x 10(-6) mutations per locus per generation, a rate substantially
below that of microsatellite repeat units in mammals studied to date (range
= 10(-2)-10(-5) per locus per generation). To obtain a more precise
estimate of mutation rate for dinucleotide repeat motifs alone, we assayed
39 new dinucleotide repeat microsatellite loci in the mutation accumulation
lines from our earlier study. Our estimate of mutation rate for a total of
49 dinucleotide repeats is 9.3 x 10(-6) per locus per generation, only
slightly higher than the estimate from our earlier study. We also estimated
the relative difference in microsatellite mutation rate among di-, tri-,
and tetranucleotide repeats in the genome of D. melanogaster using a method
based on population variation, and we found that tri- and tetranucleotide
repeats mutate at rates 6.4 and 8.4 times slower than that of dinucleotide
repeats, respectively. The slower mutation rates of tri- and
tetranucleotide repeats appear to be associated with a relatively short
repeat unit length of these repeat motifs in the genome of D. melanogaster.
A positive correlation between repeat unit length and allelic variation
suggests that mutation rate increases as the repeat unit lengths of
microsatellites increase.
相似文献