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111.
Protein glycosylation in Campylobacter jejuni: partial suppression of pglF by mutation of pseC 下载免费PDF全文
Campylobacter jejuni has systems for N- and O-linked protein glycosylation. Although biochemical evidence demonstrated that a pseC mutant in the O-linked pathway accumulated the product of pglF in the N-linked pathway, analyses of transformation frequencies and glycosylation statuses of N-glycosylated proteins indicated a partial suppression of pglF by pseC. 相似文献
112.
Ganesan PL Alexander SI Watson D Logan GJ Zhang GY Alexander IE 《Cancer immunology, immunotherapy : CII》2007,56(12):1955-1965
Successful immunotherapy of solid tumors has proven difficult to achieve. The aim of the current study was to further investigate
the effects of peripheral CD80-mediated co-stimulation on the efficacy of polyclonal anti-tumor effector CTL in an adoptive
transfer model. Splenocytes obtained from wild-type mice immunized with CD80-transduced EL4 tumor cells were expanded in vitro
in the presence of either IL-12 or IL-15 and irradiated CD80-transduced EL4 tumor cells. Polyclonal CD8 T cells were the major
subset in the effector population. Primed effector cells were adoptively transferred into immuno-deficient Rag-1-deficient
mice which were then challenged with syngeneic vector-control or CD80-transduced EL4 tumor cells. Expression of CD80 enhanced
the elimination of EL4 tumors and mouse survival. Both IL-12 and IL-15 cultured cells had enhanced cytotoxicity. Importantly,
anti-tumor memory was maintained without tumor evasion following re-challenge with either CD80-transduced and vector-control
EL4 cells. We also show, using antibody-mediated depletion, that endogenous NK cells present in Rag-1-deficent mice exert
anti-EL4 tumor activity that is enhanced by CD80 expression. Collectively these data show that peripheral co-stimulation by
tumor expression of CD80 results in enhanced anti-tumor efficacy of NK and polyclonal effector T cells, and suggest that TCR
repertoire diversity helps protect against tumor escape and provides memory with resultant robust immunity to subsequent tumor
challenge irrespective of CD80 status. 相似文献
113.
T.C. Chen K.S. Persons S. Zheng J. Mathieu M.F. Holick Y.F. Lee B. Bao M.A. Arai A. Kittaka 《The Journal of steroid biochemistry and molecular biology》2007,103(3-5):717
1α,25-Dihydroxyvitamin D3 (1α,25(OH)2D3) is known to inhibit the proliferation and invasiveness of prostate cancer cells. However, 1α,25(OH)2D3can cause hypercalcemia and is not suitable as a therapeutic agent. 19-Nor-vitamin D derivatives are known to be less calcemic when administered systemically. In order to develop more potent anti-cancer agents with less calcemic side effect, we therefore utilized 3H-thymidine incorporation as an index for cell proliferation and examined the antiproliferative activities of nine C-2-substituted 19-nor-1α,25(OH)2D3 analogs in the immortalized PZ-HPV-7 normal prostate cell line. Among the nine analogs we observed that the substitution with 2α- or 2β-hydroxypropyl group produced two analogs having antiproliferative potency that is approximately 500- to 1000-fold higher than 1α,25(OH)2D3. The 3H-thymidine incorporation data were supported by the cell counting data after cells were treated with 1α,25(OH)2D3, 19-nor-2α-(3-hydroxypropyl)-1α,25(OH)2D3 or 19-nor-2β-(3-hydroxypropyl)-1α,25(OH)2D3 for 7 days. 19-Nor-2α-(3-hydroxypropyl)-1α,25(OH)2D3 and 19-nor-2β-(3-hydroxypropyl)-1α,25(OH)2D3 were also shown to be about 10-fold more active than 1α,25(OH)2D3 in cell invasion studies using prostate cancer cells. In conclusion, a substitution at the C-2 position of 19-nor-1α,25(OH)2D3 molecule with a hydroxypropyl group greatly increased the antiproliferative and anti-invasion potencies. Thus, these two analogs could be developed to be effective therapeutic agents for treating early and late stages of prostate cancer. 相似文献
114.
An evaluation of the vitamin D3 content in fish: Is the vitamin D content adequate to satisfy the dietary requirement for vitamin D? 总被引:1,自引:0,他引:1
Z. Lu T.C. Chen A. Zhang K.S. Persons N. Kohn R. Berkowitz S. Martinello M.F. Holick 《The Journal of steroid biochemistry and molecular biology》2007,103(3-5):642
It has been suggested that the major source of vitamin D should come from dietary sources and not sun exposure. However, the major fortified dietary source of vitamin D is milk which often does not contain at least 80% of what is stated on the label. Fish has been touted as an excellent source of vitamin D especially oily fish including salmon and mackerel. Little is known about the effect of various cooking conditions on the vitamin D content in fish. We initiated a study and evaluated the vitamin D content in several species of fish and also evaluated the effect of baking and frying on the vitamin D content. Surprisingly, farmed salmon had approximately 25% of the vitamin D content as wild salmon had. The vitamin D content in fish varied widely even within species. These data suggest that the tables that list the vitamin D content are out-of-date and need to be re-evaluated. 相似文献
115.
Dennis T. Logan 《人类与生态风险评估》2007,13(2):302-316
This article provides a perspective on recent research on the effects of PAHs on fish. Fish are visible members of aquatic communities that are vulnerable to PAH contamination. The ecotoxicology of fish and PAHs can be complex. Fish are a diverse group that can have complicated life cycles and behavior and can be exposed to PAH-contaminated sediments and water by a variety of routes, including respiration; ingestion of food, sediment, and detritus; and dermal absorption. PAHs are a complex group of chemicals with similar chemical structure but a variety of chemical and physical attributes and are usually produced and occur in the environment as mixtures. Individual PAHs may elicit a variety of effects in different fish species, and different PAHs may elicit different effects in any single fish species. The variation in both fish and PAHs is reflected in the wide range of adverse effects observed in fish exposed to PAHs. Some observed effects include narcosis, mortality in all life stages, decrease in growth, lower condition factor, edema, cardiac dysfunction, a variety of deformities, lesions and tumors of the skin and liver, cataracts, damage to immune systems and compromised immunity, estrogenic effects, bioaccumulation, bioconcentration, trophic transfer, and biochemical changes, some of which can be used as biomarkers. 相似文献
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117.
Superovulation could potentially increase embryo recovery for immediate transfer or cryopreservation. The objectives were to evaluate the effect of pretreatment with progesterone and estradiol (P+E) on follicular response to eFSH and compare doses of eFSH and ovulatory agents on follicular development and ovulation in mares. In Experiment 1, 40 mares were assigned to one of four treatment groups. Group 1 consisted of untreated controls. Group 2 mares were administered eFSH without pretreatment with P+E. Group 3 mares were administered P+E for 10 days starting in mid-diestrus followed by eFSH therapy. Group 4 mares were administered P+E for 10 days followed by eFSH therapy. All treated mares were administered 12.5mg eFSH twice daily and prostaglandins were given on the second day of eFSH therapy. Mares were bred with fresh semen the day of hCG administration and with cooled semen the following day. The numbers of preovulatory follicles and ovulations were lower for mares treated with P+E prior to eFSH treatment. Pretreatment with P+E in estrus also resulted in a lower embryo recovery rate per ovulation compared to the other two eFSH treatment groups. In Experiment 2, two doses of eFSH (12.5 and 6.25mg) and two ovulation-inducing agents (hCG and deslorelin) were evaluated. The number of preovulatory follicles was greater for mares given 12.5mg of eFSH compared to mares given 6.25mg. Number of ovulations was greatest for mares given 12.5mg of eFSH twice daily followed by administration of hCG. Embryo recovery per flush was similar among treatment groups, but the percent of embryos per ovulation was higher for mares given the low dose of eFSH. In summary, there was no advantage to giving P+E prior to eFSH treatment. In addition, even though the lower dose of eFSH resulted in fewer ovulations, embryo recovery per flush and embryo recovery per ovulation were similar or better for those given the lower dose of eFSH. 相似文献
118.
Stringer AM Gibson RJ Logan RM Bowen JM Yeoh AS Burns J Keefe DM 《Experimental biology and medicine (Maywood, N.J.)》2007,232(1):96-106
The microflora of the gastrointestinal tract (GIT) are a complex ecosystem, performing a number of beneficial functions. Irinotecan causes both early and late diarrhea, the latter possibly caused, in part, by changes in the microflora of the GIT. Female DA rats were given atropine subcutaneously, prior to a single 200 mg/kg intraperitoneal dose of irinotecan. Animals were monitored for diarrhea and killed at 30 and 60 mins, 2, 6, 12, 24, 48, and 72 hrs after chemotherapy administration. Control rats received no treatment. Fecal samples and stomach, jejunum, and colon samples were collected and stored at -70 degrees C until required. Standard microbiological culture techniques were used to grow and isolate the flora. Biochemical tests were used to identify the bacteria. The level of growth was noted for relative comparison between time points and graded accordingly. Early diarrhea was observed in the rats from 2-6 hrs after treatment, after which time the diarrhea resolved. Late onset diarrhea was apparent 72 hrs after treatment. Changes were seen in the flora of the stomach, jejunum, colon and feces. The majority of microflora changes were seen 6, 12, and 24 hrs after treatment, with a relative increase or decrease in the presence of bacteria in comparison with control rats. In some rats bacteria were not observed at all time points, and different bacteria not seen in control animals were identified in rats treated with irinotecan. These changes were observed up to 72 hrs after treatment. In conclusion, irinotecan treatment causes changes in the flora of the stomach, jejunum, colon, and feces of rats and is associated with the development of diarrhea. These changes in flora may have systemic effects and in particular may contribute to the development of chemotherapy-induced mucositis. 相似文献
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