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991.
Suk Hee Lee Suk Oh Young Il Kim Sang Cheol Jun Sang Sup So Hwan Gyu Kim 《Biotechnology and Bioprocess Engineering》2007,12(2):100-105
Phellinus linteus is a fungus which is found primarily in tropical regions of the Americas, Africa, and Asia.P. linteus has been used in traditional medical practice for the treatment of arthritis, liver damage and cancer. Angiogenesis is a
process that involves migration, proliferation and cell differentiation, as well as the formation of new capillary structures.
The anti-angiogenic activities evidenced by natural compounds may actually be a critical effect for the inhibition of angiogenesis-dependent
disease by these agents via the blockage of vascular development. This study assessed the effects of water extracts fromP. linteus (Phellinus extracts) on primary cultured porcine coronary artery endothelial cells (PCAECs).Phellinus extracts induced no changes in DNA synthesis or cell numbers, but inhibited the migration of PCAECs.Phellinus extracts also induced a reduction in the secretion of matrix metalloproteinase-2 (MMP-2) and MMP-9. Our results show that,
in endothelial cells,Phellinus extracts may inhibit angiogenesis by reducing levels of MMP-2 and MMP-9 secretion. 相似文献
992.
以下胚轴、带柄子叶和茎尖为外植体,利用根癌农杆菌和基因枪法将抗虫融合蛋白基因(Bt-CpTI)导人甘蓝品种“中甘8号”,得到了13株卡那霉素抗性植株。经PCR扩增反应和Southern blot分子验证表明:农杆菌介导转化下胚轴和带柄子叶来源的Ⅰ型抗性植株均为转基因植株,而农杆菌介导转化茎尖外植体得到的Ⅱ型抗性植株属“假阳性”植株,基因枪介导转化茎尖的2株Ⅲ型植株中,有1株是非转基因植株。经胰蛋白酶抑制剂活性分析和抗虫测试证明,部分转基因植株有较高的胰蛋白酶抑制剂活性和抗菜青虫能力。 相似文献
993.
为阐明功能性α2-肾上腺素受体(α2-AR)的特性及其与α1-AR的相互关系,以离体大鼠主动脉为模型,进行收缩功能实验,发现在大鼠主动脉中,α1-AR和α2-AR产可介导其收缩效应并以α1-AR折作用为主,α1-AR可增强α2-AR介导的收缩效应,而α2-AR则对α1-AR介导的收缩效应无影响,在不可逆阻断α1-AR而保留α2-AR的条件下,α2-AR介导的缩血管效应消失,仅在阈值浓度的KCl存在下才能显示,且收缩幅度较对照组显著降低,结果表明,在离体大鼠主体动脉中存在功能性α2-AR,α2-AR的缩血管作用依赖于α1-AR的激动,其最大收缩反应远远小于α1-AR。 相似文献
994.
Recovery of transgenic plants by pollen-mediated transformation in <Emphasis Type="Italic">Brassica juncea</Emphasis> 总被引:1,自引:0,他引:1
The aroA-M1 encoding the mutant of 5-enolpyruvyl-shikimate-3-phosphate synthase (EPSPS) was introduced into the Brassica juncea genome by sonication-assisted, pollen-mediated transformation. The plasmid DNA and collected pollen grains were mixed in
0.3 mol/L sucrose solution and treated with mild ultrasonication. The treated pollen was then pollinated onto the oilseed
stigmas after the stamens were removed artificially. Putative transgenic plants were obtained by screening germinating seeds
on a medium containing glyphosate. Southern blot analysis of glyphosate-resistant plants indicated that the aroA-M1 gene had been integrated into the oilseed genome. Western blot analysis further confirmed that the EPSPS coded by aroA-M1 gene was expressed in transgenic plants. The transgenic plants exhibited increased resistance to glyphosate compared to untransformed
plants. Some of those transgenic plants had considerably high resistance to glyphosate. The genetic analysis of T1 progeny further confirmed that the inheritance of the introduced genes followed the Mendelian rules. The results indicated
that foreign genes can be transferred by pollen-mediated transformation combined with mild ultrasonication. 相似文献
995.
目的:观察同型半胱氨酸对血管内皮功能的影响,并探讨通心络超微粉的干预作用。方法:健康雄性Wis-tar大鼠,随机分为对照组、模型组、通心络组。离体主动脉环技术检测血管内皮依赖性舒缩功能,微循环仪观察肠系膜微循环变化,放免方法检测血浆内皮素(ET)、血管紧张素Ⅱ(AngⅡ)、血栓素(TXA2)、前列环素(PGI2)的含量及血清超氧化物歧化酶(SOD)与谷胱苷肽过氧化物酶(GSH-Px)的活性、一氧化氮(NO)及丙二醛(MDA)的含量。结果:与对照组比较,模型组血管内皮依赖性舒张反应明显减弱(p〈0.01),肠系膜毛细血管对乙酰胆碱的扩张幅度与扩张率显著下降(P〈0.05)。与模型组比较,通心络组血管舒张反应明显改善(P〈0.01),肠系膜毛细血管对乙酰胆碱反应性升高;与对照组比较,模型组AngⅡ、ET、TXA2含量明显升高(P〈0.05,p〈0.01),而PGI2含量明显降低(P〈0.05),同时血清中SOD与GSH-Px活力、NO含量明显降低(P〈0.001,P〈0.05)。与模型组比较,通心络组血浆AngⅡ、ET、TXA2的含量显著降低(P〈0.01),而PGI2的含量明显升高(P〈0.01),同时血清中SOD活力与NO含量显著升高(P〈0.01,P〈0.05)。结论:①高同型半胱氨酸血症可使内皮依赖性血管舒缩功能减退,其机制可能与高同型半胱氨酸血症引发血管舒缩因子平衡紊乱及大量自由基的产生有关。②通心络超微粉可使同型半胱氨酸所致血管内皮依赖性舒张功能的异常明显改善,可能与其抑制自由基的过量生成及调节内皮舒缩因子的平衡有关。 相似文献
996.
小麦TaMlo基因的原核表达、抗体制备及细胞化学分析(简报) 总被引:1,自引:0,他引:1
白粉病菌(Blumeria graminis)是一类高度专化性的寄生真菌,可侵染650多种单子叶植物和 9000多种双子叶植物,能够引起多种麦类作物的白粉病,给农业生产带来巨大的损失。由于白粉病菌生理小种多、变异快,所以利用专化性抗病基因难以解决植物的持久抗病性问题。人们在研究大麦白粉病时.发现大麦Mlo基因的隐性突变可导致大麦对绝大多数白粉病菌生理小种的高效持久的广谱抗病性。Schulze-Lefert等多家实验室合作于1997年成功克隆了野生的 Mlo基因。进一步研究表明.该基因编码一种植物特有的具有7个跨膜区和羧基端长尾的膜蛋白(Mlo),它可能对植物细胞的坏死起负调控作用。但Mlo基因如何表达及其在白粉病菌发育中的作用机制尚不清楚。 相似文献
997.
Chunbo Hao Hongxun Zhang Richard Haas Zhihui Bai Baoguo Zhang 《World journal of microbiology & biotechnology》2007,23(1):15-21
A sediment sample (pH 2.5) was collected at an acid mine drainage site in Anhui, China. The present acidophilic microbial
community in the sediment was studied with a 16S rRNA gene clone library. Small-subunit rRNA genes were PCR amplified, cloned
and screened by amplified rDNA restriction analysis (ARDRA). Subsequently, 10 different clones were identified and they were
affiliated with Acidobacteria, β/γ-Proteobacteria, δ-Proteobacteria, Nitrospira, Candidate division TM7, and Low G + C Gram-positives. Phylogenetic analysis of 16S rRNA gene sequences revealed a diversity
of acidophiles in the sediment that were mostly novel. Unexpectedly, 16S rRNA gene sequences affiliated with δ-Proteobacteria were found to constitute more than 60% of clone library. To our knowledge, this is the first occasion that bacteria of δ-Proteobacteria have been found dominant in the acidic habitat. Anaerobic sulfate- or metal reduction is the predominant physiological trait
of bacteria of this subdivision. The high sulfate, ferric iron and the presence of bioavailable carbon in the anaerobic microenvironment
may result in the dominance of bacteria of δ-Proteobacteria. 相似文献
998.
A thermophilic bacterial strain GXN151 which could degrade Avicel efficiently was isolated and identified as Bacillus licheniformis. A genomic library of GXN151 was constructed and two novel endoglucanase genes designated cel9A and cel12A were isolated by screening the library on carboxylmethyl cellulase indicator plates. The analysis of amino acid sequences deduced from the genes indicated that Cel9A consisted of a catalytic domain belonging to glycosyl hydrolase family 9, a linker domain, and a carbohydrate binding module family 3 from N-terminal to C-terminal; Cel12A had only one catalytic domain belonging to glycosyl hydrolase family 12. The combinations of Cel9A and Cel12A produced by the recombinant E. coli exhibited synergistic action against substrates of carboxylmethyl cellulose as well as Avicel. 相似文献
999.
Sediment quality criteria in use around the world 总被引:20,自引:0,他引:20
There have been numerous sediment quality guidelines (SQGs) developed during the past 20 years to assist regulators in dealing
with contaminated sediments. Unfortunately, most of these have been developed in North America. Traditionally, sediment contamination
was determined by assessing the bulk chemical concentrations of individual compounds and often comparing them with background
or reference values. Since the 1980s, SQGs have attempted to incorporate biological effects in their derivation approach.
These approaches can be categorized as empirical, frequency-based approaches to establish the relationship between sediment
contamination and toxic response, and theoretically based approaches that attempt to account for differences in bioavailability
through equilibrium partitioning (EqP) (i.e., using organic carbon or acid volatile sulfides). Some of these guidelines have
been adopted by various regulatory agencies in several countries and are being used as cleanup goals in remediation activities
and to identify priority polluted sites. The original SQGs, which compared bulk chemical concentrations to a reference or
to background, provided little insight into the ecosystem impact of sediment contaminants. Therefore, SQGs for individual
chemicals were developed that relied on field sediment chemistry paired with field or laboratory-based biological effects
data. Although some SQGs have been found to be relatively good predictors of significant site contamination, they also have
several limitations. False positive and false negative predictions are frequently in the 20% to 30% range for many chemicals
and higher for others. The guidelines are chemical specific and do not establish causality where chemical mixtures occur.
Equilibrium-based guidelines do not consider sediment ingestion as an exposure route. The guidelines do not consider spatial
and temporal variability, and they may not apply in dynamic or larger-grained sediments. Finally, sediment chemistry and bioavailability
are easily altered by sampling and subsequent manipulation processes, and therefore, measured SQGs may not reflect in situ
conditions. All the assessment tools provide useful information, but some (such as SQGs, laboratory toxicity and bioaccumulation,
and benthic indices) are prone to misinterpretation without the availability of specific in situ exposure and effects data.
SQGs should be used only in a “screening” manner or in a “weight-of-evidence” approach. Aquatic ecosystems (including sediments)
must be assessed in a “holistic” manner in which multiple components are assessed (e.g., habitat, hydrodynamics, resident
biota, toxicity, and physicochemistry, including SQGs) by using integrated approaches.
Received: December 26, 2000 / Accepted: December 28, 2001 相似文献
1000.
Eutrophication assessment and bioremediation strategy in a marine fish cage culture area in Nansha Bay,China 总被引:3,自引:0,他引:3
On the basis of field data measured during four cruises from January to November 2007, variations in the characteristics of
dissolved inorganic nitrogen and phosphate were analyzed in Nansha marine fish cage culture area, Ningbo City, China. Dissolved
inorganic nitrogen (DIN) was selected as the parameter to balance seaweed absorption and fish DIN production. The contents
of DIN and phosphate varied with different seasons, and eutrophication index (E) value ranged from 2.41 to 15.99, indicating serious eutrophication conditions; the annual average value of N/P of 32.95
indicates a nitrogen surplus in this system. The eutrophication condition in Nansha Bay was mainly caused by the fish cage
culture activities. Based on their biological characteristics, Laminaria and Gracilaria were selected as the bioremediation species in winter and spring and summer and autumn, respectively. The optimal co-cultivation
proportion of fish cage to Laminaria and Gracilaria in this bay was 1 cage, 450 m2 and one cage, 690 m2, respectively. 相似文献