首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
Liposomes from egg yolk lecithin and egg yolk lecithin/ganglioside are cytotoxic for Trypanosoma brucei and Trypanosoma congolense bloodstream forms in vitro. The trypanocidal effect is influenced by the liposome age and concentration. This effect is diminished in the presence of whole blood in vitro and could not be observed in vivo. Freeze-fractured parasite membrane showed an intramembranous particle aggregation after incubation with liposomes. Liposomes from egg yolk lecithin kill trypanosomes more rapidly than do liposomes from egg yolk lecithin/cholesterol.  相似文献   

2.
C. difficile toxin A causes the rounding up and the formation of surface blebs in normal rat intestinal crypt cells (IEC-6). These phenomena, together with the inhibition of DNA synthesis and the cell lysis, could be the mechanisms leading the toxin-treated cells to death.  相似文献   

3.
4.
5.
We have determined the nucleotide sequence recognized by the restriction endonuclease Hae II from Haemophilus aegyptius which cleaves the simian virus 40 (SV40) DNA at a single specific site. By using terminal radioactive labeling of the cleavage site at both the 5′ and 3′-ends we have deduced the recognition sequence,
with elements of a two-fold rotational symmetry. The endonuclease produces staggered ends with protruding 3′-terminated single-strands, four nucleotides in length. In plasmid RSF 2124 DNA, which contains multiple Hae II cleavage sites, it was observed that the 5th nucleotide from the 3′ terminus is either a pdA or a pdG, indicating alternating recognition sequences.  相似文献   

6.
7.
8.
The ability of various prostaglandins (PGs) to affect the in vitro anamnestic immune response of keyhole limpet hemocyanin (KLH)-primed rabbit popliteal lymph node cells was investigated. Of the four PGs studied (PGA1, PGE2 and PGF), PGE1 was found to have a stimulatory effect, whereas PGA1, PGE2 and PGF were ineffective in stimulating or inhibiting the in vitro anamnestic response. Under the conditions studied, a 3.5-fold increase in antibody production was obtained in PGE1-treated, KLH-stimulated cultures. Maximum enhancement was obtained when 0.2 μg of PGE1 were added at the time of culture initiation and were allowed to remain in contact with the lymph node cells for 24 hours.  相似文献   

9.
10.
11.
12.
13.
14.
15.
16.
From the leaves of Agavelecheguilla Torrey, two steroidal sapogenin diols have been isolated. Mass spectral, infra-red and nuclear magnetic resonance data of these two compounds showed them to be (25R) spirost-5-ene-2α, 3β-diol (yuccagenin) and (25R)-5β-spirostane-3β,6α-diol. The latter is a new compound to which the trivial name ruizgenin has been given.  相似文献   

17.
18.
A cDNA coding mutated cecropin CMIV fromBombyx mori was synthesized according to its amino acid sequence usingE. coli biased codons. The gene was cloned into the fusion expression vector pEZZ318 and was expressed inE. coli HB101. The fusion protein produced was purified by affinity chromatography to yield 26 mg/L fusion product. The anti-bacterial activities of recombinant cecropin CMIV were recovered after cleavage by chemical method.  相似文献   

19.
The synthesis and testing of several diazocarbonyl JH analogs (diazo JHA) which act as photoaffinity labels for insect juvenile hormone binding proteins are described. The best competitor, 10,11-epoxyfarnesyl diazoacetate, has been shown to irreversibly reduce [3H]-JH III binding to both ovarian and hemolymph JHBP from Leucophaeamaderae after irradiation at 254 nm for 20 seconds. No loss of activity was observed after incubation of JHBP and diazo JHA without irradiation. Protection from photoinactivation by diazo JHA II was achieved by the presence of an equimolar amount of JH III during the photolysis. Photoaffinity labeled proteins show loss of binding capacity without alteration of the binding affinity. This is the first example of the use of a photoaffinity label in the study of JH action on a molecular level, and may become a valuable tool in the elucidation of JH-receptor-chromatin interactions.  相似文献   

20.
The inclusion of either lactosylcerebroside or dimannosyldiglyceride at a 9% molar ratio in small unilamellar vesicles increased by two-three fold the fraction of the I.V. dose that appeared in mouse liver. For lactosylcerebroside containing liposomes, the half-time for clearance from plasma was 1.2 hours compared to 5.5 hours for liposomes of similar size, charge, and composition but lacking the glycolipid. Uptake of the lactosylcerebroside containing liposomes by the liver could be significantly reduced but not eliminated by the simultaneous injection of asialoorosomucid.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号