黄精凝集素PCL-2诱导人前列腺癌LNCap细胞凋亡及机制研究

研究黄精凝集素PCL-2对人前列腺癌LNCap细胞生物活性和可能的抗肿瘤机制。从黄精药材中提取分离得到黄精凝集素PCL-2,体外培养LNCap细胞,采用WST-1和集落形成实验评价PCL-2对LNCap细胞的增殖作用;2,7-二氯荧光黄双乙酸盐(DCFH-DA)荧光探针法检测LNCap细胞内ROS含量;qRT-PCR和Western blot法检测PCL-2对LNCap细胞中相关基因和蛋白表达的影响。研究结果显示PCL-2能显著抑制LNCap细胞的增殖,促进细胞中ROS生成;PCL-2通过上调LNCap细胞中Bax、Caspase-3及Caspase-9基因mRNA和蛋白表达并下调Bcl-2基因mRNA和蛋白表达水平诱导LNCap细胞凋亡。本研究结果表明PCL-2诱导LNCap细胞凋亡活性作用显著,可作为抑制前列腺癌的潜在药物。     

Effect of hydration degree of aerosol OT reversed micelles and surfactant concentration in heptane on spectral and catalytic properties of catalase.

The influence of micelle hydration degree (w0) and AOT concentration on fluorescence, circular dichroism (CD), catalytic activity, and stability of catalase in Aerosol OT (AOT) reversed micelles in heptane was investigated. The quantitative parameters--differential fluorescence of catalase (DeltaI), protein molar ellipticity ([theta]lambda), initial rate of catalytic reaction, catalase efficiency (kcat/Km), and rate constant of enzyme inactivation (kin, sec-1)--decreased with increasing AOT concentration in micellar systems, reflecting the interaction of solubilized catalase with the AOT micellar aggregates in heptane. The dependences of all these parameters on increasing hydration degree of micelles (w0) were characterized by the appearance of maxima at w0 of 8, 15-18, and 26-30. These maxima are suggested to reflect three different states of catalase in the micellar system, distinguished by their conformations and catalytic activity, which is determined by the micellar microenvironment of the enzyme.     

PpsbA驱动的类金属硫蛋白基因smtA在鱼腥藻的表达和镉离子抗性的提高

金属硫蛋白 (Metallothionein,简称MT)是一类富含半胱氨酸、具有很强金属结合能力的小分子量蛋白。       

Ascorbate content of wheat leaves is not determined by maximal l-galactono-1,4-lactone dehydrogenase (GalLDH) activity under drought stress

Although ascorbic acid (AA) is a high-abundance metabolite, relatively little is known about the factors controlling its accumulation in leaves. To address this issue, we examined the role of l -galactono-1,4-lactone dehydrogenase (GalLDH), the enzyme which catalyses the last step of this pathway, in the control of AA content under optimal and stress conditions. In a range of species, no clear relationship between AA content and leaf GalLDH protein and activity was found under optimal growth conditions. To explore the effect of drought stress on GalLDH activity and protein content, wheat (Triticum aestivum L.) was selected for detailed analysis, using two cultivars that differ in their constitutive AA level. In well-watered plants, the AA content of cv Buck Chambergo (BCH) was over twice that of cv Cooperativa Maipún (CM) but dehydroascorbic acid content was similar in both cv. In agreement with this, dehydroascorbate reductase and glutathione reductase activities were higher in cv BCH than in cv CM, indicating a higher capacity for AA regeneration. Neither leaf DHA content nor activities of AA regenerating enzymes were modified by drought. Although drought caused a substantial increase in GalLDH protein and activity in the low AA cv CM, this treatment had no effect on these parameters in cv BCH. Notably, leaf AA content was unaffected by drought in either cv. These results suggest that GalLDH protein and activity cannot be used as an indicator for changes in the capacity for ascorbate biosynthesis and that AA biosynthesis is constrained by other factors under stress. This can be explained by the importance of regeneration in maintaining AA levels and possibly also by redox regulation of GalLDH.     

Temperature and Food as Factors Influencing Oxygen Consumption of Intertidal Organisms, Particularly Limpets

SYNOPSIS: In intertidal animals rates of oxygen consumptionspan an order of magnitude (even when standardised for bodysize and temperature). This may reflect different adaptationsto this variable habitat. Temperatures range widely and potentiallyincrease metabolic expenditure during the heat of the day, whileperiods of feeding may be restricted. The balance between intakeand expenditure of energy may limit zonation, body size, andeven mode of reproduction. One pattern is that species sufferingshortage of food ("conservers") have low rates of oxygen consumptionwhile those with abundant food ("exploiters") have high rates.Conservers appear to have several means of reducing metaboliccosts, but exploiters maintain high (seemingly wasteful) ratesof oxygen consumption. Oxygen consumption cannot, however, be considered separately,since it reflects turnover,including growth rate and reproductiveoutput. There is also the question whether differences betweenspecies are genetically controlled, or simply phenotypic responsesto food availability. Comparisons of populations with differentamounts of food suggest that exploiters substantially reduceoxygen consumption when food is scarce, but conservers are relativelyfixed in their pattern of slow growth and low reproductive output,even if food is experimentally increased. Growth and reproduction are positively correlated, at leastwithin taxonomically related groups (as exemplified by patellaceanlimpets) but both are inversely related to longevity.Thus growthand reproduction are not necessarily "traded off," but are bothlow in "conservers" and both high in "exploiters."     

''Ciliated'' Tumour Cells In Ascitic Fluid From Two Cases of Cystadenocarcinoma of the Ovary

We report two cases of primary carcinoma of the ovary in which 'ciliated' adenocarcinoma cells were found in the ascitic fluid. Transmission electron microscopy revealed that these were not true cilia but rather a prolific growth of abnormal microvilli. The cytological findings were compared with the histological appearances of the primary tumour. No ciliated cells were seen in the primary tumour, suggesting that the formation of the microvilli represented an independent proliferation of the cells in the fluid. Special staining reactions for mucin, alkaline phosphatase and epithelial membrane antigen were identical in the primary tumour and the cells in the ascitic fluid.     

Contrasting age structures in cave cricket populations: patterns and significance

Abstract.

• 1 Adaptation to life in caves, as a seasonally constant environment, is expected to affect several life history traits. In this paper we investigate the age structure and phenology of twenty-seven Dolichopodu cave cricket populations from artificial and natural caves subjected to different environmental regimes and to different availability of food resources.
• 2 Morphometric data clearly revealed the occurrence of different age structures and phenology, basically indicating two contrasting patterns.
• 3 In artificial caves, which have been colonized by Dolichopoda only in historical times and where food resources and climate are chiefly dependent upon surface environment, age structure was seasonal. In contrast, in most natural caves, where cricket colonization appears to be much older and stability of both climatic parameters and trophic resources is higher, age structure was diverse and aseasonal.
• 4 However, a seasonal age structure also occurs in natural caves characterized by either recent origin or by a low temperature regime. This suggests that age structure in Dolichopoda is influenced by historical factors, stability of food resources and also by environmental stress.

     

体外细胞核组装中核纤层与核膜的关系

采用非洲爪蟾卵提取物非细胞体系,以外源Lambda DNA诱导细胞核的体外组装,以此实验模式为基础,研究了细胞核体外组装过程中核纤层的组装,结果表明核纤层蛋白参与细胞核的体外组装过程,核内骨架的组装与核纤层的组装在时间上是有序的,核内骨架的组装可能为核纤层的装配提供了先决条件.在非洲爪蟾卵提取物非细胞体系中加入抗核纤层蛋白抗体,抑制核纤层的正常装配过程,核膜组装发生异常.结果提示核纤层的组装与核膜的组装是密切相关的.     

用2-D-NMR测定人卵泡促性腺激素释放肽类似物TF14的溶液构象

人卵泡促性腺激素释放肽(hF-GRP)被发现以后,人们合成了许多类似物以便寻找其激动剂或抑制剂,类似物TF14的活性就比hF-GRP强近1倍,为了探求结构活性关系,用2-D-NMR技术(TOCSY,ROESY)测定了TF14的溶液构象,得到了与hF-GRP有显著不同的结果,该14肽整个处于1个非典型的伸展结构.