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排序方式: 共有67条查询结果,搜索用时 31 毫秒
31.
在土培条件下,提高氮素供应水平和NaCl处理浓度后大麦幼苗地上部和根中的全氮,蛋白质氮和游离氨基酸总量增加;蛋白质氮占全氮的比值亦因NaCl处理浓度的增大而提高。在盐胁迫下,游离脯氨酸占氨基酸总量的百分比明显增加,而谷氨酸所占比例则下降。  相似文献   
32.
利用大肠杆菌获得玉米叶绿体atpB融合基因及非融合基因的高效表达。从大肠杆菌中部分分离纯化得到的这些atpB基因表达产物都表现出微弱的水解ATP的活力。由其中一种融合蛋白β_1制备得到的抗血清对菠菜叶绿休偶联因子的光合磷酸化功能影响不明显,对游离CF_1的Ca~(2+)-ATP酶活力也无明显影响,但却能明显地促进它的Mg~(2+-)ATP酶活力。  相似文献   
33.

Background

Polymorphisms are associated with chronic thromboembolic pulmonary hypertension (CTEPH) and pulmonary thromboembolism (PTE), but no polymorphism specific to CTEPH but not PTE has yet been reported. Fibrin resistance is associated with CTEPH, but the mechanism has not been elucidated.

Methods

Polymorphisms were analyzed in 101 CTEPH subjects, 102 PTE subjects and 108 healthy controls by Massarray or restriction fragment length polymorphism (RFLP). Plasmin-mediated cleavage of fibrin was characterized in 69 subjects (29 with CTEPH, 21 with PTE and 19 controls).

Results

Genotype frequencies and allele frequencies of fibrinogen Aα Thr312Ala were significantly higher in CTEPH subjects than in controls and PTE subjects, while there was no difference between PTE subjects and controls. The odd ratio (OR 2.037) and 95% confidence interval (95% CI, 1.262–3.289) showed that Thr312Ala polymorphism was a risk factor for CTEPH but not PTE. Fibrin from CTEPH subjects was more resistant to lysis than that from PTE subjects and controls. Fibrin resistance was significantly different between Aα Thr312Ala (A/G) genotypes within CTEPH subjects, and the fibrin with GG genotype was more resistant than that with AA and AG genotype.

Conclusions

Fibrinogen Aα Thr312Ala (A/G) polymorphism was associated with CTEPH, but not PTE, suggesting that the fibrinogen Aα Thr312Ala polymorphism may act as a potential biomarker in identifying CTEPH from PTE. GG genotype polymorphism contributes to CTEPH through increasing fibrin resistance, implying that PTE subjects with fibrinogen Aα GG genotype may need long-term anticoagulation therapy.  相似文献   
34.
沈杰  刘振国  沈芳  吉挺 《昆虫学报》2013,56(10):1117-1126
【目的】本研究旨在克隆卡尼鄂拉蜂Apis mellifera carnica锌转运蛋白 7相似蛋白(zinc transporter 7-like, ZnT-7-like)基因, 制备ZnT-7-like多克隆抗体, 了解该基因在卡尼鄂拉蜂王浆腺中不同时期的差异表达情况。【方法】运用RT PCR法从卡尼鄂拉蜂王浆腺总RNA中扩增ZnT-7-like基因, 进行生物信息学分析, 为避开跨膜结构的干扰, 选择克隆其部分序列(273 bp)作为多肽免疫序列。将其亚克隆入原核表达载体pGEX-4T-1, 转入大肠杆菌Escherichia coli BL21 (DE3)中诱导表达获得融合蛋白, 然后将融合蛋白纯化后免疫新西兰大白兔制备多克隆抗体, 分别用间接ELISA和Western blot检测抗体的效价和特异性, 最后采用实时荧光定量RT-PCR以及Western blot技术检测该基因在不同日龄成虫王浆腺中的相对表达量。【结果】克隆得到卡尼鄂拉蜂ZnT-7-like基因, 大小为1 065 bp。SDS-PAGE电泳结果显示融合蛋白成功表达; 制备的多克隆抗体效价高达1∶64 000, 且具有很高的特异性。ZnT-7-like在卡尼鄂拉蜂5个日龄成虫中的转录情况存在较大差异, 表现为3日龄成虫中的表达量极显著高于其他日龄(P<0.01), 12日龄表达量最低, 其他日龄间表达量两两差异显著(P<0.05)或极显著(P<0.01); ZnT-7-like蛋白表达与转录水平基本一致。【结论】成功克隆了卡尼鄂拉蜂ZnT-7-like基因, 制备了兔抗蜂ZnT-7-like多克隆抗体, 并在转录和翻译两个水平上测定了ZnT-7-like在卡尼鄂拉蜂王浆腺中不同时期的相对表达量。这些结果为深入研究卡尼鄂拉蜂ZnT-7-like基因的功能奠定了基础。  相似文献   
35.
中国大口涡虫属一新种记述(大口虫目,大口虫科)   总被引:10,自引:6,他引:4  
记述大口涡虫属1新种,即厦门大口涡虫Macrostomum xiamensis sp.nov..新种的主要鉴别特征是几丁质交接刺光滑、较细长,表面无几丁质瓣膜.其远端呈螺旋状弯曲,弯曲部的平面上夹角达60度,压片后的夹角达100度,螺旋部超过半圈,交接刺末端呈注射器针的末端,开口于螺旋状弯曲面的外侧.标本采自厦门市区菩陀寺的淡水荷花池塘内,水质属富营养型.所有标本保存在深圳大学生命科学学院实验室.  相似文献   
36.
Li BL  Zhang ZG  Du LL  Wang W 《Chirality》2008,20(1):35-39
The resolutions of (9-anthryl)methoxyacetic acid (9AMAA) and (9-anthryl)hydroxyacetic acid (9AHAA) were performed by capillary electrophoresis using hydroxypropyl-beta-cyclodextrin (HP-beta-CD) as a chiral selector. Various factors affecting migration time and resolutions of these compounds were investigated with a run voltage of 20 kV, column temperature 20 degrees C and 20 mM Tris-H(3)PO(4) buffer (pH 6.5) containing 5 mM HP-beta-CD for 9AMAA, or 10 mM HP-beta-CD for 9AHAA, (+/-)-9AMAA and (+/-)-9AHAA were successfully separated at Rs 3.27 and 1.92, respectively.  相似文献   
37.
芸薹链格孢(Alternariabrassicae)在PD液体培养基中黑暗培养20d,过滤获得培养滤液,经乙酸乙酯萃取、45℃减压浓缩得AB-粗毒素。AB-粗毒素经HPLC分析,在λ=206nm波长下具有Ⅰ、Ⅱ、Ⅲ和Ⅳ4个明显的吸收峰。组分Ⅲ的红外吸收光谱、FAB/MASS和1H-NMR与已报道的腐败菌素B基本一致,由此确定组分Ⅲ为腐败菌素B。试验发现,芸薹链格孢的培养滤液、AB-粗毒素和毒素组分Ⅲ均能造成白菜叶片黄化、萎蔫和坏死。  相似文献   
38.
夏大豆田稗草的生态经济防治阈期研究   总被引:6,自引:0,他引:6  
由振国 《生态学报》1993,13(4):334-341
本文提出了杂草生态经济防治阈期的概念。并在北京地区1984和1985年田间试验的基础上,建立了苗后放任的免除夏大豆田稗草生长的相对天数与大豆相对产量的函数关系及其生态经济防治阈期的计算模型。利用此模型计算的结果表明,夏大豆田稗草的生态经济防治阈期处在大豆苗后生育期总天数的16.8%-26.0%之间,即按绝对天数计算,北京地区夏大豆田该杂草的生态经济防治阈期约处在大豆苗后15-23d之间,此期保持无  相似文献   
39.
A series of 4-hydroxybenzene acrylic acid derivatives were designed and synthesized based on the ferulic acid of natural active ingredients. The tested compound 5a, 5f and 6a have significant anti-inflammatory activity with suppression rates of 45.29%, 44.75% and 24.11%, respectively, compared with that of indomethacin, and their cardiac toxicity was not observed. The structure-function relationship shows that the p-hydroxyl group on the α-position benzene ring, particularly if acetylated, contributes to the considerable anti-inflammatory activity; that the carboxyl group on the double bond, if esterified, also contributes to the anti-inflammatory activity; that the p-methylsulfonyl group on the other benzene ring, whose introduction is due to the COX-2 selectivity, also contributes to anti-inflammatory activity surprisingly.  相似文献   
40.
Carrot (Daucus carota L.) is an important food crop and is useful for studying carotenogenesis due to the quantity and diversity of carotenoids in its roots. Phytoene synthase catalyzes the first committed step in the carotenoid biosynthesis pathway, and its overexpression is the main driving force in the orange phenotype. At present, we lack fundamental knowledge of the role of these genes and their effects on carotenoid accumulation in leaves. In the present study, three backcross inbred lines (BC2S4) with different colored roots derived from a cross between the orange inbred line (Af) and related wild species were used to investigate the role of the duplicated DcPSY genes in root carotenogenesis. Promoter analysis showed that DcPSY genes have diverged substantially in their regulatory sequences after gene duplication. Expression levels of DcPSY1 and DcPSY2 were generally positively correlated with carotenoid content during root development. In mature leaves, total carotenoid content was higher than that in the roots, DcPSY1 expression increased extremely higher than DcPSY2 expression compared with roots, and DcPSY1 was more sensitive than DcPSY2 during leaf de-etiolation under sunlight. These results suggest that DcPSY1 seems to make an important contribution to carotenoid accumulation in the leaves and is important for photosynthesis and photoprotection, but they are not the determining factors of root color. This expands our understanding of the regulation of carotenoid biosynthesis in carrot.  相似文献   
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