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1.
近年来,由于光化学反应引起的臭氧(O3)前体物增加,使全球植物受近地层O3胁迫的程度越来越严重。在东欧、西欧以及美国,O3污染被认为是造成大片森林植被衰退和枯死的主要原因。本研究通过对亚热带城市南昌城区至郊区森林植被的实地调查,结合2014年4-8月南昌近地层O3浓度实时监测数据,并参考O3伤害评估手册中的鉴别方法和标准,分析了南昌市近地层O3时空分布特征及其对木本植物叶片的伤害情况。结果显示:近郊区的O3浓度显著高于远郊区和城区;6月份的O3平均浓度最高,其累计剂量(AOT40)达35.5 mg·m-3·h,远远超过了植物受O3伤害的临界值(19.6 mg·m-3·h),即已经对植物造成了危害;在南昌市近郊区和远郊区,共有16种植物表现出典型的O3伤害症状,如叶缘干枯,叶片表面出现有色斑点、斑块、条带状变色等,其中东京樱花(Cerasus yedoensis(Mats.)Yüet Li)、紫楠(Phoebe sheareri(Hemsl.)Gamble)、闽楠(P.bournei(Hemsl.)Yang)、山鸡椒(Litsea cubeba(Lour.)Pers.)可作为南昌地区的O3污染指示物种。  相似文献   

2.
Explants of cotton (Gossypium hirsutum L. cv. Jingmian 7) were transformed with Agrobacterium tumefaciens (Smith et Townsend ) Conn LBA4404 harboring an expression cassette composed of CoYMV (Commelina Yellow Mottle Virus) promoter-gus-nos terminator on the plant expression vector pBcopd2. Transgenic plants were regenerated and selected on a medium containing kanamycin. GUS (β-glucuronidase) activity assays and Southern blot analysis confirmed that the chimerical gus gene was integrated into and expressed in the regenerated cotton plants. Plant expression vector pBI121 was also transferred into the same cotton variety and the regenerated transgenic plants were used as a positive control in GUS activity analysis. Evidences from histochemical analysis of GUS activity demonstrated that under the control of a 597 bp CoYMV promoter the gus gene was highly expressed in the vascular tissues of leaves, petioles, stems, roots, hypocotyls, bracteal leaves and most of the flower parts while GUS activity could not be detected in stigma, anther sac and developing cotton fibers of the transgenic cotton plants. GUS specific activity in various organs and tissues from transgenic cotton lines was determined and the results indicated that the CoYMV promoter-gus activities were at the same level or higher than that of CaMV 35S promoter-gus in leaf veins and roots where the vascular tissues occupy a relatively larger part of the organs, but in other organs like leaves, cotyledons and hypocotyls where the vascular tissues occupy a smaller part of the organs the CoYMV promoter-gus activity was only 1/3-1/5 of the CaMV 35S promoter-gus activity. The GUS activity ratio between veins and leaves was averaged 0.5 for 35S-GUS plants and about 2.0 for CoYMV promoter-gus transgenic plants. These results further demonstrated the vascular specific property of the promoter in transgenic cotton plants. An increasing trend of GUS activity in leaf vascular tissues of transgenic cotton plants developing from young to older was observed.  相似文献   

3.
建立一种靶点蛋白质快速定量检测方法。在原有侧向流动免疫层析技术的基础上,通过优化层析材料和纳米微球的均一性、改进检测区的检测方法,经逐点扫描技术,建立标准浓度曲线,以达到对临床靶点蛋白质的定量检测。以乳腺癌组织中的Her2表达为例,通过对已知浓度样品的检测,验证本技术方法的准确度大于96%。另外,以蛋白质免疫印迹作为组织中特定蛋白质检测金标准,分析临床肿瘤组织中Her2蛋白的含量,其准确率也达到95.5%,而免疫组织化学方法检测准确率仅为69.58%。新型免疫层析法检测结果与靶向治疗患者的愈后密切相关(P<0.01)。改进后的新型免疫层析方法能够准确地对临床靶点蛋白质进行定量检测,而且结合侧向流动技术的简单、快速和易用性,这种新型检测方法可以广泛应用于临床组织标本、血液标本和体液标本中靶点蛋白质的临场定量检测,在一定程度上可以替代免疫组化技术。  相似文献   

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5.
Cytochrome P450 family 24 subfamily A member 1 (CYP24A1) gene is overexpressed in many cancers including colorectal cancer (CRC) and correlated with tumor invasion, lymph node metastasis, and the reduced overall survival. We predicted that miR-30a and miR-125a regulate the CYp24A1 gene expression. Therefore, we performed a case-control study using 800 individuals, including 389 patients with CRC and 411 noncancer controls to evaluate the association between miR-30a rs2222722 and miR-125a rs12976445 polymorphisms, located at in the promoter region, and the risk of sporadic CRC in an Iranian population. The genotyping assay for both polymorphisms was performed using Tetra-primer amplification refractory mutation systems polymerase chain reaction. The results indicated that the frequency of the miR-30a rs2222722 CT genotype was significantly different in the studied groups ( P = 0.0001; odds ratio [OR] = 1.9; 95% confidence interval [CI], 1.39-2.60). Also, a significant difference was observed under the dominant inheritance model ( P = 0.0001; OR = 1.8; 95% CI, 1.33-2.43). The frequency of the miR-30a rs2222722 T allele was significantly associated with increased CRC risk in the studied population ( P = 0.0019; OR = 1.47; 95% CI, 1.15-1.89). Taken together, our study provides preliminary evidence that the rs2222722 polymorphism increases the susceptibility to CRC in an Iranian population. Therefore, the affecting factors on CYP24A1 gene expression such as microRNAs can be considered as risk factors for CRC.  相似文献   

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7.
【目的】作为一种喜温冷敏植物,低温严重影响小桐子的生长发育、地域分布与产量。前期工作发现12 ℃低温锻炼可显著提高小桐子的抗冷性,小桐子早期光诱导蛋白(ELIP)基因是低温高响应基因。为探究JcELIP在小桐子低温响应中的作用,全面了解JcELIP的结构、调控机制、进化关系及JcELIP与miRNAs的互作关系,也为后续小桐子抗冷分子育种提供一个重要的候选基因资源。【方法】通过RT-PCR克隆了小桐子JcELIP基因并对其进行了系统的生物信息学分析,采用RT-qPCR分析了JcELIP基因在根、茎、叶中及12 ℃低温锻炼过程中的表达变化,鉴定了与JcELIP互作的miRNAs,进行了12 ℃低温锻炼过程中的共表达分析。【结果】结果显示,该基因完整的开放阅读框(ORF)为585 bp,编码194个氨基酸,蛋白大小为2.04 kD,理论等电点为9.59,属于稳定的疏水碱性蛋白,具有3个疏水跨膜螺旋;三级结构主要由ɑ-螺旋和无规则卷曲组成,具有叶绿素a/b结合位点。顺式作用元件预测显示JcELIP具有脱落酸等激素响应元件。进化分析显示,小桐子JcELIP与木薯MeELIP同源性最高。RT-qPCR分析显示,正常生长条件下小桐子JcELIP在根、茎、叶中的表达量无显著差异;12℃冷锻炼条件下JcELIP在叶中表达快速上调,48 h时其表达量达到对照组的64.8倍,表明JcELIP参与了小桐子对冷胁迫的响应与适应。基于小桐子降解组数据,鉴定到miR390-x、miR6476-x和novel-m0090-3p等8个miRNAs对JcELIP的表达具有调控作用;共表达分析结果表明在12 ℃低温锻炼过程中JcELIP的表达受miR390-x和novel-m0090-3p显著的负调控。  相似文献   

8.
Barrier to autointegration factor 1 (BANF1) is a DNA-binding protein found in the nucleus and cytoplasm of eukaryotic cells that functions to establish nuclear architecture during mitosis. The cDNA and the genomic sequence of BANF1 were cloned from the Giant Panda (Ailuropoda melanoleuca) and Black Bear (Ursus thibetanus mupinensis) using RT-PCR technology and Touchdown-PCR, respectively. The cDNA of the BANF1 cloned from Giant Panda and Black Bear is 297 bp in size, containing an open reading frame of 270 bp encoding 89 amino acids. The length of the genomic sequence from Giant Panda is 521 bp, from Black Bear is 536 bp, which were found both to possess 2 exons. Alignment analysis indicated that the nucleotide sequence and the deduced amino acid sequence are highly conserved to some mammalian species studied. Topology prediction showed there is one Protein kinase C phosphorylation site, one Casein kinase II phosphorylation site, one Tyrosine kinase phosphorylation site, one N-myristoylation site, and one Amidation site in the BANF1 protein of the Giant Panda, and there is one Protein kinase C phosphorylation site, one Tyrosine kinase phosphorylation site, one N-myristoylation site, and one Amidation site in the BANF1 protein of the Black Bear. The BANF1 gene can be readily expressed in E. coli. Results showed that the protein BANF1 fusion with the N-terminally His-tagged form gave rise to the accumulation of an expected 14 kD polypeptide that formed inclusion bodies. The expression products obtained could be used to purify the proteins and study their function further.  相似文献   

9.
目的 肺癌在生物学特性、基因组变异、增殖速度及化疗响应方面的时间异质性,构成了对有效治疗的显著阻碍。肺癌时间异质性的复杂性,结合其空间异质性,为研究带来了极大挑战。本文将为肺癌研究开辟新的方向,有助于更深入地理解肺癌的时间异质性,从而提升对肺癌的治疗成功率。方法 应用拉曼光谱显微技术作为监测肺癌细胞生物分子组成实时变化的有力工具,揭示了疾病的时间异质性。通过拉曼光谱与多元统计分析的结合,对苯并(a)芘处理后人类肺上皮细胞的生物分子变化进行了细致观察。结果 随时间推移,核酸、脂质、蛋白质及类胡萝卜素含量呈现下降趋势,而葡萄糖浓度上升。这些变化模式暗示,苯并(a)芘可导致遗传物质结构损伤、促进脂质过氧化、干扰蛋白质代谢、降低类胡萝卜素生成,并改变葡萄糖代谢路径。运用拉曼光谱技术,以实时、无侵入性、非破坏性的方式监控肺癌细胞内的生物分子动态,进而阐明其关键分子特性。结论 本项研究深化了对肺癌演进的认识,并为发展个性化治疗策略提供支持,助力提升患者的临床治疗效果。  相似文献   

10.
This study innovates an assessment technique to evaluate heavy metal toxic load (HMTL). Assessment of surface water in Durgapur industrial area, West Bengal India illustrates that heavy metals in majority of sampling locations exceed the drinking water quality standards. Therefore, pollution status and health impact were predicted by heavy metal pollution index (HPI) and hazard index (HI). More than 50% of sampling locations were marked as polluted. Moreover, 5% and 90% of sampling locations near the industries have health risk to adult and child on ingestion. The study of specific exposure-time and exposure-duration affirms the suitability of water for fishing and regular activities. However, HPI or HI does not quantify heavy metal concentrations that pose threat to human health. Therefore, the proposed assessment technique, HMTL, determines the concentration of heavy metals responsible for health hazard. HMTL identifies Mn, Pb, and Co as toxic metals and estimates 85%, 63%, and 70% removal of these metals from surface water to limit pollution. Origins of metals were also investigated through statistical techniques, which revealed that Fe has geogenic and anthropogenic source, while other metals originate by anthropogenic activities solely. This study demonstrates that HMTL will help the planning authority to document effective water quality management plan.  相似文献   

11.
根据日本晴cab4基因序列(GenBank:AK104499.1)设计引物,用RT-PCR的方法从籼稻9311中克隆了叶绿素a/b结合蛋白基因的全长cDNA,命名为cab-9311(cab gene from 9311)。insilico分析表明:cab-9311与cab4基因同源性为99%,编码的蛋白含有244个氨基酸,与cab4基因编码的蛋白同源性为98%。蛋白分子质量为26.9kD,理论等电点为6.52。第54位~第216位氨基酸是一个典型的叶绿素a/b结合蛋白功能域(chlorophyll a/bbinding domain)。跨膜分析和蛋白质三级预测显示,该蛋白在C端有一个典型的跨膜区。亚细胞定位分析表明该蛋白定位于叶绿体,是一个叶绿体内囊体膜上的锚定蛋白。  相似文献   

12.
13.
The factors controlling the stability, folding, and dynamics of integral membrane proteins are not fully understood. The high stability of the membrane protein bacteriorhodopsin (bR), an archetypal member of the rhodopsin photoreceptor family, has been ascribed to its covalently bound retinal cofactor. We investigate here the role of this cofactor in the thermodynamic stability and folding kinetics of bR. Multiple spectroscopic probes were used to determine the kinetics and energetics of protein folding in mixed lipid/detergent micelles in the presence and absence of retinal. The presence of retinal increases extrapolated values for the overall unfolding free energy from 6.3 ± 0.4 kcal mol− 1 to 23.4 ± 1.5 kcal mol− 1 at zero denaturant, suggesting that the cofactor contributes 17.1 kcal mol− 1 towards the overall stability of bR. In addition, the cooperativity of equilibrium unfolding curves is markedly reduced in the absence of retinal with overall m-values decreasing from 31.0 ± 2.0 kcal mol− 1 to 10.9 ± 1.0 kcal mol− 1, indicating that the folded state of the apoprotein is less compact than the equivalent for the holoprotein. This change in the denaturant response means that the difference in the unfolding free energy at a denaturant concentration midway between the two unfolding curves is only ca 3-6 kcal mol− 1. Kinetic data show that the decrease in stability upon removal of retinal is associated with an increase in the apparent intrinsic rate constant of unfolding, kuH2O, from ~1 × 10− 16 s− 1 to ~1 × 10− 4 s− 1 at 25 °C. This correlates with a decrease in the unfolding activation energy by 16.3 kcal mol− 1 in the apoprotein, extrapolated to zero SDS. These results suggest that changes in bR stability induced by retinal binding are mediated solely by changes in the activation barrier for unfolding. The results are consistent with a model in which bR is kinetically stabilized via a very slow rate of unfolding arising from protein-retinal interactions that increase the rigidity and compactness of the polypeptide chain.  相似文献   

14.
目的:研究高密度脂蛋白/低密度脂蛋白比值(HDL/LDL比值)、脂蛋白a(LP(a))及超敏C反应蛋白(s-CRP)与冠脉病变程度之间的关系。方法:对120名初发急性STEMI行急诊冠脉造影术并支架植入术患者(<12小时),并于次日晨检测空腹生化血脂分析,测得HDL/LDL比值、LP(a)及s-CRP等相关指标,冠脉造影结果根据Gensini积分系统分轻、中、重度三组,比较三组之间上述三项指标有无差异,并选取冠脉造影正常20例为对照组,比较各组间有无差异。结果:与正常组相比,心梗组HDL/LDL比值明显降低(P<0.05),各组间HDL/LDL比值亦存在差异(P<0.05),LP(a)及s-CRP在不同冠脉分级上亦存在着差异(P<0.05),以上差异均有统计学意义。结论:上述三项指标对冠脉病变严重程度有一定的预测价值。  相似文献   

15.
ABSTRACT

Exposure to benzo(a)pyrene (B(a)P) for health risk was studied in soils from the Delhi region, India. The mean and median concentrations of benzo(a)pyrene were 0.031 and 0.029 (±0.002) mg/kg, respectively. The lifetime average daily dose (LADD) for adults and children was 1.7 × 10?8 mg kg?1 d?1 and 7.5 × 10?8 mg kg?1 d?1, respectively, with incremental life time cancer risk (ILCR) of 1.2 × 10?7 and 5.5 × 10?7, respectively. The Index of Additive Cancer Risk (IACR) was 0.084. Our screening-level risk assessment shows that the observed ILCR and IACR values are much lower than the guideline values of 10?6 ? 10?4 (ILCR) and <1 (IACR), respectively, and therefore the measured B(a)P levels in soil may not portend environmental and human health risks.  相似文献   

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The nucleotide sequence of a cluster of ribosomal protein genes in the plastid genome of a unicellular red alga, Cyanidioschyzon merolae, which has been supposed to be the most primitive alga, was determined. The phylogenetic tree inferred from the amino acid sequence of ribosomal proteins of two rhodophytes, a chromophyte, a glaucophyte, two chlorophytes (land plants), a cyanobacterium, and three eubacteria suggested a close relationship between the cyanobacterium Synechocystis PCC6803 and the plastids of various species in the kingdom Plantae, which is consistent with the hypothesis of the endosymbiotic origin of plastids. In this tree, the two species of rhodophytes were grouped with the chromophyte, and the glaucophyte was grouped with the chlorophytes. Analysis of the organization of the genes encoding the ribosomal proteins suggested that the translocation of the str cluster occurred early in the lineage of rhodophytes and chromophytes after these groups had been separated from chlorophytes and glaucophytes. Received: 2 June 1997 / Accepted: 15 July 1997  相似文献   

18.
By pretreating etiolated cucumber cotyledons with kinetin in the dark, it was observed that the plastids isolated from such tissues were 400% more active in the conversion of δ-aminolevulinic acid into protochlorophyllide, than plastids prepared from water-treated controls. The experimental evidence is consistent with the hypothesis that (a) the kinetin dark-pretreatment of the etiolated tissue, uncouples the joint biosynthesis of prothylakoids and protochlorophyll and results in the accumulation of excess prothylakoid membranes poorly supplied with protochlorophyllide (b) upon isolation of the plastids and incubation with δ-aminolevulinic acid, the latter is very rapidly converted into membrane-bound protochlorophyllide.  相似文献   

19.
Postural control research describes ankle-, hip-, or multi-joint strategies as mechanisms to control upright posture. The objectives of this study were, first, development of an analysis technique facilitating a direct comparison of the structure of such multi-segment postural movement patterns between subjects; second, comparison of the complexity of postural movements between three stances of different difficulty levels; and third, investigation of between-subject differences in the structure of postural movements and of factors that may contribute to these differences.  相似文献   

20.
SlyD, the sensitive-to-lysis protein from Escherichia coli, consists of two domains. They are not arranged successively along the protein chain, but one domain, the “insert-in-flap” (IF) domain, is inserted internally as a guest into a surface loop of the host domain, which is a prolyl isomerase of the FK506 binding protein (FKBP) type. We used SlyD as a model to elucidate how such a domain insertion affects the stability and folding mechanism of the host and the guest domain. For these studies, the two-domain protein was compared with a single-domain variant SlyDΔIF, SlyD* without the chaperone domain (residues 1-69 and 130-165) in which the IF domain was removed and replaced by a short loop, as present in human FKBP12. Equilibrium unfolding and folding kinetics followed an apparent two-state mechanism in the absence and in the presence of the IF domain. The inserted domain decreased, however, the stability of the host domain in the transition region and decelerated its refolding reaction by about 10-fold. This originates from the interruption of the chain connectivity by the IF domain and its inherent instability. To monitor folding processes in this domain selectively, a Trp residue was introduced as fluorescent probe. Kinetic double-mixing experiments revealed that, in intact SlyD, the IF domain folds and unfolds about 1000-fold more rapidly than the FKBP domain, and that it is strongly stabilized when linked with the folded FKBP domain. The unfolding limbs of the kinetic chevrons of SlyD show a strong downward curvature. This deviation from linearity is not caused by a transition-state movement, as often assumed, but by the accumulation of a silent unfolding intermediate at high denaturant concentrations. In this kinetic intermediate, the FKBP domain is still folded, whereas the IF domain is already unfolded.  相似文献   

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