镉胁迫对拟南芥的毒害作用及自噬现象的观测

镉离子(Cd2+)具有强植物毒性,可抑制植物生长,甚至导致植物死亡。为了研究重金属镉对拟南芥的毒害作用,采用叶绿素荧光技术、流式细胞技术、激光共聚焦技术及半定量RT-PCR技术,检测光合参数的变化、活性氧(reactive oxygen species,ROS)的累积、自噬的发生,以及病原相关蛋白(pathogenesis-related protein,PR)基因表达的变化。实验结果显示,随着50μmol/L CdCl2处理时间的延长,ROS和Cd2+在细胞中大量积累。而在镉胁迫的初期,会观察到自噬的发生及PR基因表达的变化。说明植物受到外界Cd2+作用的初期,会通过自噬及增强PR基因表达来抵抗外界胁迫。但随着处理时间的延长,植物细胞内累积了大量的ROS和Cd2+,当植物不足以通过自噬途径抵抗胁迫时,就会导致生长受阻,最终对光合系统造成损伤。     

光学分子影像技术及其在药物研发领域的应用

光学分子影像技术是一种发展迅速的生物医学影像技术,能够利用生物发光技术或荧光蛋白等,对生物体内特定的生物过程进行无创的定性或定量研究。应用该技术可以对药物进行筛选,选取具有潜在治疗效果的药物进行后续研究,而终止对可能无效药物的研究,同时可以评价药物对肿瘤的代谢、增殖、血管形成、凋亡和组织乏氧等方面的影响。本文主要介绍光学分子影像技术及其在药物研发,尤其是抗肿瘤药物研发领域的应用。     

Interaction of hydrogen sulfide and estrogen on the proliferation of vascular smooth muscle cells

Hydrogen sulfide (H(2)S) can be endogenously generated from cystathionine gamma-lyase (CSE) in cardiovascular system, offering a cardiovascular protection. It is also known that the lower risk of cardiovascular diseases in female is partially attributed to the protective effect of estrogen. The current study explores the interaction of H(2)S and estrogen on smooth muscle cell (SMC) growth. In the present study, we found that the proliferation of cultured vascular SMCs isolated from wild-type mice (WT-SMCs) was inhibited, but that from CSE gene knockout mice (CSE-KO-SMCs) increased, by estrogen treatments. The expression of estrogen receptor α (ERα), but not ERβ, was significantly decreased in CSE-KO-SMCs compared with that in WT-SMCs. Exogenously applied H(2)S markedly increased ERα but not ERβ expression. In addition, the inhibition of ER activation and knockdown of ERα expression in WT-SMCs or the overexpression of ERα in CSE-KO-SMCs reversed the respective effects of estrogen on cell proliferation. The expression of cyclin D1 was reduced in WT-SMCs but increased in CSE-KO-SMCs after estrogen treatments, which was reversed by knockdown of ERα in WT-SMCs or overexpression of ERα in CSE-KO-SMCs, respectively. The overexpression of cyclin D1 in WT-SMCs or knockdown of cyclin D1 expression in CSE-KO-SMCs reversed the effects of estrogen on cell proliferation. These results suggest that H(2)S mediates estrogen-inhibited proliferation of SMCs via selective activation of ERα/cyclin D1 pathways.     

Hydrogen sulfide as an oxygen sensor in trout gill chemoreceptors

O2 chemoreceptors elicit cardiorespiratory reflexes in all vertebrates, but consensus on O2-sensing signal transduction mechanism(s) is lacking. We recently proposed that hydrogen sulfide (H2S) metabolism is involved in O2 sensing in vascular smooth muscle. Here, we examined the possibility that H2S is an O2 sensor in trout chemoreceptors where the first pair of gills is a primary site of aquatic O2 sensing and the homolog of the mammalian carotid body. Intrabuccal injection of H2S in unanesthetized trout produced a dose-dependent bradycardia and increased ventilatory frequency and amplitude similar to the hypoxic response. Removal of the first, but not second, pair of gills significantly inhibited H2S-mediated bradycardia, consistent with the loss of aquatic chemoreceptors. mRNA for H2S-synthesizing enzymes, cystathionine beta-synthase and cystathionine gamma-lyase, was present in branchial tissue. Homogenized gills produced H2S enzymatically, and H2S production was inhibited by O2, whereas mitochondrial H2S consumption was O2 dependent. Ambient hypoxia did not affect plasma H2S in unanesthetized trout, but produced a PO2-dependent increase in a sulfide moiety suggestive of increased H2S production. In isolated zebrafish neuroepithelial cells, the putative chemoreceptive cells of fish, both hypoxia and H2S, produced a similar approximately 10-mV depolarization. These studies are consistent with H2S involvement in O2 sensing/signal transduction pathway(s) in chemoreceptive cells, as previously demonstrated in vascular smooth muscle. This novel mechanism, whereby H2S concentration ([H2S]) is governed by the balance between constitutive production and oxidation, tightly couples tissue [H2S] to PO2 and may provide an exquisitely sensitive, yet simple, O2 sensor in a variety of tissues.     

具有吸收状态的昆虫种群矩阵模型的研究

在Vandermeer的昆虫矩阵模型的基础上,提出了具有吸收状态的昆虫种群矩阵模型。并且导出了k步吸收状态与转移状态的矩阵表达式,将有助于昆虫种群动态的研究．     

SRIF及CSH对斜带石斑鱼脑垂体生长激素合成和分泌的调控

斜带石斑鱼 (Epinepheluscoioides)属于雌性先成熟、具有性转变的雌雄同体鱼类。生长激素释放抑制因子 (SRIF)是鱼类生长激素 (GH)分泌的主要抑制性调节剂 ,半胱胺 (CSH)可抑制SRIF的作用。本文采用静态孵育系统 ,应用RPA及RIA研究SRIF及CSH对斜带石斑鱼GHmRNA表达及GH分泌的调节。结果显示 ,SRIF能以剂量依存方式抑制斜带石斑鱼脑垂体释放GH ,时间越长作用越强。但SRIF作用 2 4h对GHmR NA水平的影响不显著 ,表明SRIF是斜带石斑鱼GH释放的抑制性调节剂 ,对GHmRNA的表达没有明显影响。较低剂量的CSH (10 -4- 10 -2 mol/L)使斜带石斑鱼的GH释放量增加 ,较高剂量 (10 -1mol/L)的CSH引起的GH增加趋势减缓 ,这种现象可能与较高剂量的CSH不仅抑制下丘脑SRIF的释放 ,同时影响GHRH的释放 ,使得GH的分泌量增幅下降有关 ;无论是较高剂量还是较低剂量的CSH都不能使GHmRNA的水平增加 ,表明CSH只能引起GH的释放量增加 ,不影响GH的合成。GnRH与CSH共同作用引起的GH释放量明显高于CSH单独作用的效应 ,其主要原因是由于GnRH促进GHmRNA的表达所致     

广东纹胸鮡属鱼类一新种(鲇形目,鮡科)

描记纹胸属鱼类 1新种 ,珠江纹胸Glyptothoraxzhujiangensissp .nov.,采自广东新会市崖西镇白水带溪(属珠江水系 )。新种与四斑纹胸G .quadriocellatus较相近 ,但胸吸着器呈心形而不是楔形 ,腹鳍起点近吻端而不是近尾鳍基 ,头部无斑而不是在两眼后方各有 1个黄色亮斑 ,尾鳍长大于而不是小于头长 ,鳃耙数、脊椎骨数较多 ,脂鳍基较短 ,与后者明显不同。     

Adenoviral transduction of hTGF-β1 enhances the chondrogenesis of bone marrow derived stromal cells

TGF-β1 plays a necessary and important role in the induction of chondrogenic differentiation of bone marrow stromal cells (BMSCs). In this study, porcine BMSCs were infected with a replication-deficient adenovirus expression vector carrying the hTGF-β1 gene. The transduced BMSCs were cultured as pelleted micromasses in vitro for 21 days, seeded onto disk-shaped PGA scaffolds for 3 days and subsequently implanted into the subcutaneous tissue of mice. BMSCs transduced with AdhTGF-β1 expressed and secreted more hTGF-β1 protein in vitro than those of the control group. Histological and immunohistological examination of the pellets revealed robust chondrogenic differentiation. Tissues made from cells transduced with AdhTGF-β1 exhibited neocartilage formation after 3 weeks in vivo. The neocartilage occupied 42 ± 5% of the total tissue volume which was significantly greater than that of the control group. Furthermore, there was extensive staining for sulfated proteoglycans and type II collagen in the AdhTGF-β1 group compared to controls, and quantification of GAG content showed significantly greater amounts of GAG in experimental groups. The results demonstrate that transfer of hTGF-β1 into BMSCs via adenoviral transduction can induce chondrogenic differentiation in vitro and enhance chondrogenesis in vivo.     

The initial analysis of a serine proteinase gene (<Emphasis Type="Italic">AccSp10</Emphasis>) from <Emphasis Type="Italic">Apis cerana cerana</Emphasis>: possible involvement in pupal development,innate immunity and abiotic stress responses

Serine proteinases play important roles in innate immunity and insect development. We isolated a serine proteinase gene, designated AccSp10, from the Chinese honeybees (Apis cerana cerana). RT-qPCR and a Western blot analysis at different pupal development stages indicated that AccSp10 might be involved in melanin formation in pupae and promote pupal development. In adult workers, the expression of AccSp10 was upregulated by treatments mimicking harmful environments such as the presence of Bacillus bombysepticus, different temperatures (4, 24 and 42 °C), HgCl₂, H₂O₂ and paraquat; the exception was treatment with VC (vitamin C), which did not upregulate AccSp10 expression. Western blot confirmed the results. A disc diffusion assay indicated that recombinant AccSp10 accelerated E. coli cell death during stimulation with harmful substances (HgCl₂, paraquat and cumene hydroperoxide). These findings suggest that AccSp10 may be involved in the pupal development of Chinese honeybees and protection against microorganisms and abiotic harms.