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Canine transmissible venereal tumor (CTVT) can be allo-transplanted across major histocompatibility complex barriers. The expression of MHC molecules is usually low in the progression (P) stage and then greatly increases during tumor regression (R). We investigated the effects of tumor infiltrating lymphocytes (TIL) on the expression of MHC molecules of CTVT cells. Isolated, viable CTVT cells were inoculated at each of 12 sites (1 x 10(8) CTVT cells per site) on the back of six, mixed-breed dogs. Tumor masses were collected every 2-3 weeks and prepared for histopathologic, immunocytochemistry, flow cytometry and immunoblotting studies. The level of MHC expression on tumor cells from different stages of growth was measured. Initially, expression of MHC I and II molecules in P phase CTVT was low. Twelve weeks post-inoculation (PI), expression increased dramatically and it continued to increase during R phase. Tumor growth slowed after 12 weeks PI and tumors entered R phase around 17 weeks PI. We hypothesize that CTVT evades host immunosurveillance and grows progressively for 12 weeks, when it becomes vulnerable and subject to the host's anti-tumor immune responses. We further demonstrated that R phase, but not P phase, TIL were closely associated with the over-expression of MHC I and II molecules by CTVT cells. The number and proportion of TIL were higher in R phase tumors. Supernatants, from R phase co-cultures (CTVT+TIL) and TIL only, promoted MHC I and II expression on P phase CTVT cells. After culturing alone for 1 month, expression of MHC classes I and II molecules in R phase CTVT cells decreased to the level of P phase CTVT cells. However, the above-mentioned supernatants restored their expression of MHC I and II molecules. In contrast, supernatants from P phase TIL or CTVT cells increased expression slightly or had no effect. Therefore, TIL, not CTVT cells, produce the effective substance (s) to promote the expression of MHC molecules by the tumor cells. Heat treated supernatant was unable to promote the expression of MHC I and II molecules by CTVT cells. In conclusion, TIL isolated from R phase CTVT secreted a heat-sensitive, soluble substance(s) that triggered over-expression of MHC I and II after 12 weeks PI. This caused the tumor to enter R phase and helped stop CTVT growth. Our findings will facilitate the understanding and further investigation of the mechanisms that initiate host immune surveillance against tumors. 相似文献
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云南栽培稻生态型矿质元素含量的多样性 总被引:5,自引:0,他引:5
用ICP-AES测定了新平县相同生态条件下种植653份云南稻资源糙米8种矿质元素含量,并按丁颖的栽培稻生态型对其遗传多样性进行了研究。结果表明,云南水稻改良品种糙米P、Fe和Zn含量比地方稻种分别下降10.53%、14.76%和35.16%,但改良品种特别是粳稻Ca含量比地方种高, 8种矿质元素以Ca的多样性指数最大;糙米P、Ca、Mg、Fe、Zu、Cu和Mn平均含量以粳稻的Mg、Fe和Zn,水稻的P、K和Mg,陆稻的Fe和Zn,糯稻的K和Fe,早稻的Mg和Fe相对较高。8种矿质元素平均遗传多样性指数依次为粳>籼,陆>水,粘>糯,早中稻>晚稻和地方种>改良种,且P>K>Mn>Mg>Cu>Zn>Fe>Ca;其变异系数依次为Fe>Ca>Cu>Zn>Mn>K>Mg >P。 相似文献
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New dammarane-type saponins from the galls of Sapindus mukorossi 总被引:2,自引:0,他引:2
Kuo YH Huang HC Yang Kuo LM Hsu YW Lee KH Chang FR Wu YC 《Journal of agricultural and food chemistry》2005,53(12):4722-4727
Five new dammarane-type saponins, 3beta,7beta,20(S),22-tetrahydroxydammar-24-ene-3-O-alpha-l-rhamnopyranosyl-(1-->2)-beta-D-glucopyranoside, 3beta,7beta,20(S),22,23-pentahydroxydammar-24-ene-3-O-alpha-l-rhamnopyranosyl-(1-->2)-beta-D-glucopyranoside, 3beta,7beta,20(S),22,25-pentahydroxydammar-23-ene-3-O-alpha-l-rhamnopyranosyl-(1-->2)-beta-D-glucopyranoside, 25-methoxy-3beta,7beta,20(S),22-tetrahydroxydammar-23-ene-3-O-alpha-l-rhamnopyranosyl-(1-->2)-beta-D-glucopyranoside, and 25-methoxy-3beta,7beta,20(R)-trihydroxydammar-23-ene-3-O-alpha-l-rhamnopyranosyl-(1-->2)-beta-D-glucopyranoside, named sapinmusaponins A (1), B (2), C (3), D (4), and E (5), respectively, together with three known phenylpropanoid glycosides (6-8), were isolated from the galls of Sapindus mukorossi. The structures of these saponins were elucidated on the basis of spectroscopic analyses and chemical methods. Preliminary bioassay data revealed that saponins 1 and 3-5 showed moderate cytotoxic activity (ED50 approximately 9-18 microg/mL) against human tumor cell lines (Hepa59T/VGH, NCI, HeLa, and Med) and that 1-5 were inactive in vitro against HIV replication in H9 lymphocytes. 相似文献
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Paddy and Water Environment - This study proposes a risk analysis model for quantifying the insufficient risk of rice production due to the climate change and variation in irrigation water and... 相似文献
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Chemical reactions and fate of the toxins of Bacillus thuringiensis(Bt) in the soil environment are causing increasing concerns due to the large-scale cultivation of transgenic Bt plants.In this study,the effect of ionic strength(0-1 000 mmol kg 1) adjusted by NaCl or CaCl 2 on adsorption of Bt toxin by a lateritic red soil,a paddy soil and these soils after chemical removal of organic-bound or free Fe and Al oxides,as well as by pure minerals(goethite,hematite and gibbsite) which are widespread in these soils,were studied.The results indicated that when the supporting electrolyte was NaCl,the adsorption of Bt toxin by the lateritic red soil and paddy soil increased rapidly until the ionic strength reached 250 mmol kg 1 and then gradually slowed down with the increase of ionic strength;while in case the supporting electrolyte was CaCl 2,the adsorption of Bt toxin enhanced significantly at low ionic strength(< 10 mmol kg 1) and then decreased as the ionic strength increased.The adsorption of Bt toxin by the tested minerals and soils after the removal of organic-bound or free Fe and Al oxides also increased with increasing ionic strength controlled by NaCl.Removing organic-bound Fe and Al oxides obviously increased the adsorption of Bt toxin in the tested soils.Differently,removing free Fe and Al oxides increased the Bt adsorption by the paddy soil,but decreased the adsorption by the lateritic red soil.The study indicated that the varieties of ionic strength and the presence of Fe and Al oxides affected the adsorption of Bt toxin by the soils,which would contribute to the further understanding of the fate of Bt toxin in the soil environment and provide references for the ecological risk assessment of transgenic Bt plants. 相似文献
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云南地方稻矿质元素含量的变异类型与地理生态差异 总被引:12,自引:0,他引:12
以来自云南5个稻作区或16个地州的地方稻核心种质为材料,用等离子体原子发射光谱法(ICP-AES)测定了583份糙米P, K, Ca, Mg, Fe, Zn, Cu和Mn含量,并进行了8种矿质元素含量的变异类型及其地理生态差异研究。结果表明583份糙米8种矿质元素含量为P>K>Mg >Ca>Fe>Zn>Cu>Mn, 多样性指数为P>Mn>Cu>K>Mg>Zn>Fe>Ca。滇中一季籼粳稻区是高Ca(164.86 μg/g), Fe(38.33 μg/g)和Zn(39.03 μg/g)糙米的分布中心, 尤其是大理和楚雄州糙米的Ca(205.88, 223.33 μg/g), Fe(87.89, 121.45 μg/g)和Zn (44.13, 39.33 μg/g)含量在云南16个地州中最高。思茅地区是云南低磷、低钾和低镁糙米含量的分布中心;红河和文山州是云南高钾和高铜糙米的分布中心。临沧、思茅、西双版纳和德宏州是云南地方稻糙米基于8种矿质元素的遗传多样性中心,也是糙米磷含量的遗传多样性中心,这与基于云南地方稻种形态、同工酶和SSR标记确定的云南稻种遗传多样性中心有一定的相似趋势;这是本文中重要的发现之一。这些结果揭示了云南地方稻种糙米矿质元素(特别是磷)含量的多样性与稻种的遗传和基因多样性可能有某种相关。 相似文献
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Hsu YW Hsu LC Liang YH Kuo YH Pan TM 《Journal of agricultural and food chemistry》2011,59(9):4512-4518
Red mold dioscorea (RMD) is a fermented product of Monascus purpureus NTU 568 using dioscorea as culture substrate. To investigate the bioactive components of RMD, six orange pigments including four new azaphilones with yellow fluorescence, monapilol A-D (1-4), and known monascorubrin (5) and rubropunctatin (6) were isolated and characterized. Structural elucidation of new isolates was based on nuclear magnetic resonance ((1)H NMR, (13)C NMR, COSY, HMQC, and HMBC) and other spectroscopic analyses. The structures of monapilols (1-4) were similar to those of monascorubrin (5) and rubropunctatin (6); however, the hydroxyl group (8-OH) in compounds 1-4 substituted for the C-8 carbonyl in compounds 5 and 6. Biological evaluation indicated that compounds 1-4 inhibited nitric oxide (NO) production on lipopolysaccharide-stimulated RAW 264.7 cells. Compounds 1-4 also exhibited antiproliferative activities against human laryngeal carcinoma (HEp-2) and human colon adenocarinoma (WiDr). 相似文献
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Changing climate has increasingly exacerbated droughts and floods in Taiwan; therefore, it is important to understand the
actual demand of transferring Taiwan’s agricultural water. This estimation model could help the water resource agencies to
develop appropriate mechanisms for transferring agricultural water, as well as bargaining tools for water-related negotiations.
In this study, an inverse demand function estimation model for transferring agricultural water was established, and the water
usage statistics derived from the water charge agreements, covering the period from January 1989 to December 2006 and including
drought and non-drought periods, regarding the charging of water management fees and water usage fees, was applied to the
estimation model in our empirical research. The agreements were made between irrigation associations and water companies,
industrial water users, and science and industrial parks, for the purposes of strengthening irrigation management, building
usage, and disposal of remaining water. The empirical research was conducted to estimate the demand for transferring agricultural
water using double-log regression model for panel data, and analyzed with random effects models for regular conditions and
drought periods. The results showed that the inverse demand function developed in this study was able to pass Largrange multiplier
test, and adjusted R
2 for the regression were high, fitting the random effects model showing good compatibility with the sample selection. From
the results, we can verify the estimation models to forecasting models. The significant results not only prove that the model
could provide important market information for the commercialization of water resources, but water resource agencies could
also make use of this important information to develop suitable mechanisms for transferring agricultural water, as well as
bargaining tools for negotiation of water transactions. 相似文献
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四个抗草甘膦基因的抗性比较 总被引:1,自引:0,他引:1
草甘膦抗性是当代农业重要的农艺性状。为了选择最佳的抗性基因用于植物筛选标记,通过选取cp4-epsps、GR79-epsps、gat4621和GAT四个草甘膦抗性基因进行比较,在拟南芥中验证各基因对草甘膦的抗性。4个基因的转化苗经4个浓度的草甘膦喷施检测,结果显示,GAT类基因的抗性明显高于epsps类基因,基因间的差异达到了极显著水平。gat4621基因对草甘膦的抗性最好,在各浓度下存活率均表现为最高值,且抗性稳定。国内发掘的GAT基因对草甘膦也表现出良好的抗性。GAT类基因的拟南芥转化苗在喷施高浓度草甘膦条件下出现严重抽苔抑制;但在停施草甘膦后抑制解除,且可以开花结实。转epsps类基因可以获得高抗草甘膦植株,但在花期喷施草甘膦将造成败育。从基因大小及抗性强弱考虑,GAT类基因作为筛选标记基因应该更为适合。 相似文献