Apolipoprotein-J prevention of fetal cardiac myoblast apoptosis induced by ethanol

Over-consumption of ethanol (EtOH) represents a major health problem. This study was to test the cytotoxicity of EtOH in cardiac stem cells or myoblasts, and the potential protective effect of apolipoprotein-J (ApoJ), a stress-responding, chaperone-like protein in high-density lipoprotein, on EtOH-injured cardiac myoblasts. In culture, EtOH-exposed canine fetal myoblasts underwent apoptosis in a concentration- and time-dependent manner. Expression ApoJ by cDNA transfection markedly reduced EtOH-induced apoptosis in the cells. ApoJ expression also restored partially the mitochondrial membrane potential and prevented the release of cytochrome-c from mitochondria into cytoplasma. Thus, ApoJ serves as a cytoprotective protein that protects cardiac stem cells against EtOH cytotoxicity.     

广东鼎湖山自然保护区森林景观的动态模拟研究

在遥感和GIS系统支持下,以1991年和1999年两个时期的Landsat-TM合成影像为基础,利用马尔科夫模型,模拟鼎湖山自然保护区森林景观的动态演变。结果表明:常绿阔叶林面积增加,除水域外,其它面积相应减少,到达稳定期,区域内大多为常绿阔叶林,少量的混交林,其它类型几乎消失。这个趋势是和该地区森林的演替规律相符的,但是这种结果对维持保护区内的景观多样性是不利的。     

西南岩溶地区黄荆和檵木叶片结构对其生态环境的响应

应用常规石蜡切片法对生长于桂林毛村岩溶区和非岩溶区的黄荆(Vitex negundo)和檵木(Loropetalumchinense)的解剖特征进行了比较研究,并对两区的黄荆叶片表皮形态进行了扫描电镜观察.结果显示:(1)两地的黄荆叶片背面均有浓密的绒毛,但致密程度有差异,岩溶区黄荆叶片的气孔深藏于绒毛间隙,这种结构可减少水分蒸发,降低因岩溶干旱带来的水分缺失.(2)岩溶区黄荆和檵木的叶片厚度、上下表皮厚度、栅栏组织的厚度以及栅栏组织的致密程度均大于非岩溶区,这些特征有利于减少水分蒸腾.(3)岩溶区黄荆和檵木叶片的维管组织发达程度高于非岩溶区,有利于在蒸腾减小的情况下促进水分运输和营养元素的迁移,说明2种植物叶片结构特征在不同生境区的改变是其长期在岩溶区干旱环境条件下形成的适应性变化.     

Layer-by-layer self-assembly aluminum Keggin ions/Prussian blue nanoparticles ultrathin films towards multifunctional sensing applications

In this study we described the nanocomposites films of specially synthesized inorganic Prussian blue (PB) nanoparticles and polyoxocation Al₁₃ Keggin ions that possess the excellent sensing activities. Film fabrication using layer-by-layer (LBL) self-assembly technique was followed by electrochemical characterization. The assembled multilayer Al₁₃/PB films as sensor devices for both the catalytic reduction of H₂O₂ and detecting the change of relative humidity were also investigated. The sensitivity of the biosensor was 0.886 mA cm⁻² mM⁻¹, and about two orders of magnitude change in resistance was observed as the relative humidity increasing from 5 to 95%. Both sensors exhibited good reproducibility, wide linear range. The performance and multifunctional abilities of these nanocomposites promise potential applications in biosensors, environmental controlling system and biomedical devices.     

Prokaryotic expression and polyclonal antibody preparation of a novel Rab-like protein mRabL5

Rab GTPases, which belong to the Ras superfamily, represent a group of small molecular weight GTP binding proteins that are involved in various steps along the exocytic and endocytic pathways. We first identified mRabL5 (GenBank Accession No. NP_080349), a novel Mus musculus Rab-like protein, present as a Golgi-associated protein. Here we presented the results of the cloning, prokaryotic expression, purification, and polyclonal antibody production of the novel Rab-like protein. In order to obtain a specific antibody against mRabL5, we prepared two GST fusion proteins, full-length mRabL5 GST fusion protein and mRabL5 C terminus GST fusion protein, to immunize rabbits. Western blot analysis showed that both antibodies prepared against full length of mRabL5 and its C terminus, respectively, can recognize mRabL5 protein. Immunofluorescence of mRabL5 in NIH3T3 cells using the two antibodies showed its perinuclear clustering distribution pattern. The polyclonal antibodies preparation against mRabL5 provided a good tool for us to study the functional involvement of mRabL5.     

Up-regulation of connexin 43 and gap junctional intercellular communication by Coleusin Factor is associated with growth inhibition in rat osteosarcoma UMR106 cells

Gap junctions, formed by connexin (Cx) family proteins, permit direct exchange of regulatory ions and small signal molecules between neighbouring cells. Gap junctional intercellular communication (GJIC) plays an important role in maintaining the homeostasis and preventing cell transformation. Most of the tumour cells feature deficient or aberrant connexin expression and GJIC level, and restoration of connexin expression and GJIC is correlated with cell growth control. Numerous researches has suggested the possibility of connexins as potential anti-tumour targets for chemoprevention and chemotherapy. We investigated the ability of Coleusin Factor (CF, also named FSK88) to regulate the Cx43 expression and GJIC level in rat osteosarcoma UMR106 cells. The results have demonstrated that CF increased the mRNA and protein expression of Cx43 in both in a dose- and timedependent manner, and concomitant with up-regulation of Cx43, CF treatment up-regulated the diminished GJIC level in UMR106 cells as assayed by dye transfer experiments. In addition, Cx43 distribution at the plasma membrane was also enhanced dramatically by CF treatment. Furthermore, we discovered that CF was potent to inhibit the growth and proliferation of UMR106 cells. These results provide the first evidence that CF can regulate connexin and GJIC, indicating that Cx43 may be a target of CF to exert its anti-tumour effects.     

Isolation of a novel strain of Aeromonas media producing high levels of DOPA-melanin and assessment of the photoprotective role of the melanin in bioinsecticide applications

AIMS: To isolate a bacterium that produces high yield of melanin and to examine the effect of this bacterial pigment on the efficacy of a bioinsecticide. METHODS AND RESULTS: A novel melanin-producing bacterium, designated as strain WS, was isolated from the East Lake, Wuhan, China. Taxonomic studies of this strain indicate that it belongs to Aeromonas media. Physicochemical analysis of the pigment produced by strain WS (melanin WS) suggests that it is the authentic 3,4-dihydroxyphenylalanine (DOPA)-melanin. This melanin and that produced by Pseudomonas maltophilia P28 (melanin P28) share many biophysical properties, but the yield of the melanin WS is significantly higher than that of the melanin P28. In addition, the melanin WS appears to be more effective in the protection of a bioinsecticide against ultraviolet (UV) or solar radiation. At the concentration of 10 ppm, the melanin P28 exhibited no photoprotective effect on the bioinsecticide against UV radiation; in contrast, 5 ppm of melanin WS displayed an obvious protective effect. Similarly, the melanin WS displayed more protective effect on the bioinsecticide against solar radiation than the melanin P28 did over a 4-day period, with the effect being more dramatic for the last 2 days. CONCLUSIONS: We have isolated a novel bacterial strain of A. media that produces high levels of melanin. The melanin produced by this strain offers effective photoprotection of a commercial bioinsecticide BTI against UV and solar radiation. SIGNIFICANCE AND IMPACT OF THE STUDY: Our study suggests that the melanin produced by our newly isolated A. media strain has the potential to be used as a general photoprotective agent for bioinsecticides.     

Expression and bioactivity of recombinant segments of human perforin.

The aim of the study was to prepare an active recombinant human perforin by comparing 5 candidate segments of human perforin. Full-length perforin, MAC1 (28-349 aa), MAC2 (166-369 aa), C-100, and N-60 of human perforin were selected as candidate active segments and designated, respectively, HP1, HP2, HP3, HP4, and HP5. The target genes were amplified by PCR and the products were individually subcloned into pGEM-T. The genes for HP1, HP2, HP3, and HP5 were subcloned into pET-DsbA, whereas pET-41a (+) was used as the expression vector of HP4. The fusion proteins were expressed in Escherichia coli BL21pLysS(DE3) and purified using nickel nitrilotriacetic acid (NTA) agarose affinity chromatography. The hemolysis microassay was used as an activity assay of fusion protein. From this study, we obtained the recombinant plasmids pGEM-T-HP1, -HP2, -HP3, -HP4 and -HP5, consisting of 1600, 960, 600, 300bp, and 180, respectively. From these recombinant plasmids, expression plasmids were successfully constructed and expressed in E. coli BL21pLysS(DE3). The resultant fusion proteins, affinity purified using Ni-NTA, were approximately 80, 58, 45, 44, and 30 kDa, respectively. The recombinant proteins were assayed for activity on hemolysis. HP2 and HP5 were the only recombinant proteins that were active in hemolysis, and the hemolytic function was concentration dependent. These results demonstrate that active recombinant forms of perforin can be synthesized in a prokaryote model. The recombinant N-60 and MAC1 (28-349 aa) of human perforin have the function of forming pores. Our study provides the experimental basis for further investigation on the application of perforin.