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排序方式: 共有1045条查询结果,搜索用时 15 毫秒
1.
Besides vobtusine and vobtusine-lactone, deoxyvobtusine was isolated from the leaves of Voacanga grandifolia (Miq. Rolfe. Spectral and chemical evi 相似文献
2.
A bioactive peptide of 8595 Da was purified from the cell free supernatant of Lactococcus garvieae subsp. bovis BSN307T. MALDI MS/MS peptide mapping and the data base search displayed no significant similarity to any reported antimicrobial peptide of LAB. This peptide at a dose concentration of 200 µg ml−1 inhibited the growth of both Gram-positive and Gram-negative bacteria by 58–89% and a dose of 500 µg ml−1 scavenged 50% of DPPH-free radicals generated. Interestingly, cytotoxicity assay demonstrated that 17 µg ml−1 of peptide selectively inhibited 50% proliferation of mammalian cancer cell lines HeLa and MCF-7 whereas normal H9c2 cells remained unaffected. Fluorescent microscopic analysis after DAPI nuclear staining of HeLa cells showed characteristics of apoptosis and activation of caspase-3 was ascertained by caspase-3 fluorescence assay. 相似文献
3.
Joanne K. Gardner Cyril D. S. Mamotte Priya Patel Teong Ling Yeoh Connie Jackaman Delia J. Nelson 《PloS one》2015,10(4)
Dendritic cells (DCs) play an important role in the generation of anti-cancer immune responses, however there is evidence that DCs in cancer patients are dysfunctional. Lipid accumulation driven by tumor-derived factors has recently been shown to contribute to DC dysfunction in several human cancers, but has not yet been examined in mesothelioma. This study investigated if mesothelioma tumor cells and/or their secreted factors promote increases in DC lipid content and modulate DC function. Human monocyte-derived DCs (MoDCs) were exposed to human mesothelioma tumor cells and tumor-derived factors in the presence or absence of lipoproteins. The data showed that immature MoDCs exposed to mesothelioma cells or factors contained increased lipid levels relative to control DCs. Lipid accumulation was associated with reduced antigen processing ability (measured using a DQ OVA assay), upregulation of the co-stimulatory molecule, CD86, and production of the tolerogenic cytokine, IL-10. Increases in DC lipid content were further enhanced by co-exposure to mesothelioma-derived factors and triglyceride-rich lipoproteins, but not low-density lipoproteins. In vivo studies using a murine mesothelioma model showed that the lipid content of tumor-infiltrating CD4+CD8α- DCs, CD4-CD8α- DCs DCs and plasmacytoid DCs increased with tumor progression. Moreover, increasing tumor burden was associated with reduced proliferation of tumor-antigen-specific CD8+ T cells in tumor-draining lymph nodes. This study shows that mesothelioma promotes DC lipid acquisition, which is associated with altered activation status and reduced capacity to process and present antigens, which may impair the ability of DCs to generate effective anti mesothelioma T cell responses. 相似文献
4.
Biochemical characteristics of bi-resistant mutants (resistant to ethambutol plus streptomycin or isoniazid plus streptomycin)
of mycobacteria isolated by replica plating fromMycobacterium smegmatis ATCC were compared with those of the drug-susceptible strains. Reduced incorporation of [14C]uracil, [3H]lysine and [14C]acetate into RNA, protein and phospholipids respectively was seen in the resistant mutants. Total phosphorlipids were enhanced
in ethambutol plus streptomycin resistant mutant and decreased in isoniazid plus streptomycin resistant mutant. There were
similar changes in levels of individual phospholipids. The resistant mutants revealed an accumulation of phospholipids in
the cell wall, and a marked decrease of phospholipids in the cell membrane in comparison to the susceptible strain. Several
qualitative alterations in the polypeptide profile (with respect to number and molecular weight) of the crude protein extract
and of different subcellular compartments were seen in the resistant mutants. 相似文献
5.
cDNA-derived primary structure of the glycoprotein component of canine microsomal signal peptidase complex 总被引:9,自引:0,他引:9
Canine microsomal signal peptidase activity has been shown previously to co-migrate as an apparent complex of six polypeptides with molecular masses of 25, 23, 22, 21, 18, and 12 kDa. The 22- and 23-kDa species are differentially glycosylated forms of the same protein, designated SPC 22/23. The amino acid sequence of SPC 22/23 was deduced from cDNA clones. The protein is synthesized without a cleavable amino-terminal signal sequence and contains a single site for N-linked glycosylation. SPC 22/23 appears to be anchored to the rough endoplasmic reticulum membrane by a single hydrophobic segment near its amino terminus, with the remainder of the protein positioned on the lumenal side of the membrane. The amino acid sequence of SPC 22/23 shares homology with tryptic peptides derived from the hen oviduct signal peptidase glycoprotein, one of two possible proteins required for signal peptide processing in the avian system (Baker, R.K., and Lively, M.O. (1987) Biochemistry 26, 8561-8567). Therefore, the complete amino acid sequence of SPC 22/23 presented in this report corresponds to one of two possible proteins required for signal peptide processing in higher eukaryotic cells. 相似文献
6.
Summary Measurements of foliage quality, physiological, and phenological condition of sample trees were used as independent variables in multiple correlation analyses to determine their effect on female and male spruce budworm larval dry weights. Female budworm from trees high in foliar concentrations of beta-pinene, myrcene and total nitrogen weighed less than those from trees lacking these characteristics. Male budworm from trees high in foliar concentrations of alpha-pinene, myrcene, terpinolene, citronellyl acetate, and bornyl acetate weighted less than those from trees lacking these characteristics. Additionally, relatively vigorous and productive trees tended to be less susceptible (as evidenced by reduced larval weight) to budworm of either sex. 相似文献
7.
Increased permeability of the glomerular basement membrane to ferritin after removal of glycosaminoglycans (heparan sulfate) by enzyme digestion 总被引:52,自引:11,他引:41 下载免费PDF全文
Glomerular basement membranes (GBM's) were subjected to digestion in situ with glycosaminoglycan-degrading enzymes to assess the effect of removing glycosaminoglycans (GAG) on the permeability of the GBM to native ferritin (NF). Kidneys were digested by perfusion with enzyme solutions followed by perfusion with NF. In controls treated with buffer alone, NF was seen in high concentration in the capillary lumina, but the tracer did not penetrate to any extent beyond the lamina rara interna (LRI) of the GBM, and litte or no NF reached the urinary spaces. Findings in kidneys perfused with Streptomyces hyaluronidase (removes hyaluronic acid) and chondroitinase-ABC (removes hyaluronic acid, chondroitin 4- and 6-sulfates, and dermatan sulfate, but not heparan sulfate) were the same as in controls. In kidneys digested with heparinase (which removes most GAG including heparan sulfate), NF penetrated the GBM in large amounts and reached the urinary spaces. Increased numbers of tracer molecules were found in the lamina densa (LD) and lamina rara externa (LRE) of the GBM. In control kidneys perfused with cationized ferritin (CF), CF bound to heparan- sulfate rich sites demonstrated previously in the laminae rarae; however, no CF binding was seen in heparinase-digested GBM's, confirming that the sites had been removed by the enzyme treatment. The results demonstrated that removal of heparan sulfate (but not other GAG) leads to a dramatic increase in the permeability of the GBM to NF. 相似文献
8.
Heavy water caused marked gradual decrease in the weight of the body as well as the testes throughout the treatment interval ranging from 1 to 6 weeks. Following D2O oral administration, an overall significant fall in the activity of acid phosphatase and glucose-6-phosphatase was registered. On the other hand, the activity of lactic and succinic dehydrogenases, alkaline phosphatase and adenosine triphosphatase increases following D2O treatment. These changes in the enzyme activity are suggestive of an altered metabolism of the testes in response to D2O administration. Our data corroborate the view that biological systems do discriminate between H2 and D2. 相似文献
9.
Pear-shaped prostatic gland cells which surround the ejaculatory duct of Paramphistomum and Paradistomoides, secrete two types of products: (i) granules which are cytochemically complex containing lipids, proteins and polysaccharides (1:2, glycol groups) and (ii) globules which contain phospholipids only. The cytoplasm of these cells, in addition to high acid phosphatase activity, also contains RNA, proteins and polysaccharides. 相似文献
10.