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61.
To determine if deleterious effects of heat shock on embryos could be reduced in vitro by glutathione or taurine, morulae from superovulated cows were placed in modified Hams-F10 medium supplemented with 50 nM glutathione (GSH), 50 mM taurine or neither. Morulae were incubated for 2 hours at 38.5 degrees C, then at 42.0 degrees C (heat shock) or 38.5 degrees C for 2 hours and followed by incubation at 38.5 degrees C for 20 hours. Neither GSH nor taurine enhanced viability or blastocyst development at 38.5 degrees C. At 42.0 degrees C, however, GSH and taurine increased (P less than 0.02) viability (73%, 41% and 26% live for GSH, taurine and control); GSH increased (P less than 0.05) blastocyst development (55% for GSH vs. 30% for control). In conclusion, partial thermoprotection of bovine embryos from heat shock can be achieved in vitro by administration of GSH. Taurine is only slightly effective. 相似文献
62.
R. D. DRANSFIELD R. BRIGHTWELL J. KIILU M. F. CHAUDHURY D. A. AD ABIE 《Medical and veterinary entomology》1989,3(1):83-95
Seasonal changes in the mean size of tsetse, Glossina pallidipes Austen, as indicated by wing vein length, were monitored during 1983-86 at Nguruman, southwestern Kenya. Changes in size of nulliparous females and wing fray category 1 males were shown to be correlated with the relative humidity 2 months before they were captured. Soil temperature when flies were in the pupal stage had much less effect. Size dependent mortality was demonstrated, with the mean size of flies emerging from pupae significantly less than that of field-caught flies. This mortality must occur at emergence, since there was no evidence of size-dependent mortality once the flies became available to the trap. Size was correlated with density-independent mortality acting on the parent population 2 months previously. It might therefore be possible to use size as an index of the intensity of such mortality. This could be useful when assessing the level of additional mortality required to suppress tsetse populations. 相似文献
63.
Nuclear DNA sequences from late Pleistocene megafauna 总被引:6,自引:1,他引:5
We report the retrieval and characterization of multi- and single-copy
nuclear DNA sequences from Alaskan and Siberian mammoths (Mammuthus
primigenius). In addition, a nuclear copy of a mitochondrial gene was
recovered. Furthermore, a 13,000-year-old ground sloth and a 33,000-
year-old cave bear yielded multicopy nuclear DNA sequences. Thus, multicopy
and single-copy genes can be analyzed from Pleistocene faunal remains. The
results also show that under some circumstances, nucleotide sequence
differences between alleles found within one individual can be
distinguished from DNA sequence variation caused by postmortem DNA damage.
The nuclear sequences retrieved from the mammoths suggest that mammoths
were more similar to Asian elephants than to African elephants.
相似文献
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