Bioaccumulation and ROS generation in liver of Carassius auratus, exposed to phenanthrene

In the present study, the bioaccumulation and reactive oxygen species (ROS) generation were studied after fish (Carassius auratus) were exposed to different concentrations (0.01, 0.02, 0.05, 0.07 and 0.1 mg/L) of phenanthrene for 4 days. The accumulation of phenanthrene in liver increased with the exposure concentration (R(2)=0.88). A secondary spin trapping technique was used followed by electron paramagnetic resonance (EPR) analysis, to study the ROS production. The ROS generated in fish liver after exposure to phenanthrene was identified as hydroxyl radical ((*)OH). The (*)OH signal intensity of the EPR spectrum showed a significant increase (p<0.05) compared to the control when the phenanthrene concentration was as low as 0.05 mg/L. A good positive relationship (R(2)=0.97) was found between the (*)OH formation and exposure concentrations. The changes of the activities of catalase (CAT), superoxide dismutase (SOD), glutathione-S-transferase (GST), and contents of reduced glutathione (GSH) also were detected. The results clearly indicated that phenanthrene could induce (*)OH generation and result in oxidative stress in liver of fish.     

DNAzyme-based highly sensitive electronic detection of lead via quantum dot-assembled amplification labels

An electronic DNAzyme sensor for highly sensitive detection of Pb(2+) is demonstrated by coupling the significant signal enhancement of the layer-by-layer (LBL) assembled quantum dots (QDs) with Pb(2+) specific DNAzymes. The presence of Pb(2+) cleaves the DNAzymes and releases the biotin-modified fragments, which further hybridize with the complementary strands immobilized on the gold substrate. The streptavidin-coated, QD LBL assembled nanocomposites were captured on the gold substrate through biotin-streptavidin interactions. Subsequent electrochemical signals of the captured QDs upon acid dissolution provide quantitative information on the concentrations of Pb(2+) with a dynamic range from 1 to 1000 nM. Due to the dramatic signal amplification by the numerous QDs, subnanomolar level (0.6 nM) of Pb(2+) can be detected. The proposed sensor also shows good selectivity against other divalent metal ions and thus holds great potential for the construction of general DNAzyme-based sensing platform for the monitoring of other heavy metal ions.     

Chitinase III in pomegranate seeds (Punica granatum Linn.): a high-capacity calcium-binding protein in amyloplasts

Chitinases are a class of ubiquitous proteins that are widely distributed in plants. Defense is the major natural role for chitinases, primarily against fungal pathogens. Little is known regarding their non-defensive roles in seeds. In this study, a new class III chitinase from pomegranate seeds (pomegranate seed chitinase, PSC) was isolated and purified to homogeneity. The native state of PSC is a monomer with a molecular weight of approximately 30 kDa. This chitinase naturally binds calcium ions with high capacity and low affinity, suggesting that PSC is a calcium storage protein. Consistent with this idea, its amino acid sequence (inferred from cDNA) is rich in acidic amino acid residues, especially Asp, similar to reported calcium storage proteins. The presence of calcium considerably improves the stability of the protein but has little effect on its enzymatic activity. Transmission electron microscopy analyses indicate that, similar to phytoferritin, this enzyme is widely distributed in the stroma of amyloplasts of the embryonic cells, suggesting that amyloplasts in seeds could serve as an alternative plastid for calcium storage. Indeed, the transmission electron microscopy results showed that, within the embryonic cells, calcium ions are mainly distributed in the stroma of the amyloplasts, consistent with a role for PSC in calcium storage. Thus, the plant appears to have evolved a new plastid for calcium storage in seeds. During seed germination, the content of this enzyme decreases with time, suggesting that it is involved in the germination process.     

小型生物反应器内人参不定根的人参皂苷累积

对小型生物反应器(3~10 L)培养人参不定根的生长和人参皂苷(Rg1、Re、Rb1)的累积规律,以及蔗糖浓度、初始接种量对其生长和人参皂苷累积的影响进行研究。结果表明:小型生物反应器内人参不定根的最佳收获周期为7周。初始接种量和蔗糖浓度影响生物反应器内人参不定根的生长和人参皂苷的累积,20或40 g/L蔗糖对人参不定根的生长和人参皂苷的累积优于60 g/L蔗糖;5和10 L生物反应器内最佳初始接种量分别为15和30g,其不定根的生长量分别为9.29和19.17 g,人参皂苷含量分别为5.16和4.58 mg/g。生物反应器内培养7周的人参与栽培4年的人参相比,人参皂苷Rg1和Re含量相差不大,但栽培人参中Rb1的含量远高于生物反应器中所培养的人参不定根。     

濒危植物马蹄参枝叶形态变异与环境因子的相关性分析

调查马蹄参在湖南、广东、广西、云南4省9个天然种群20项枝叶的形态指标在种群内和种群间的表型变异,运用相关分析揭示枝和叶形态指标间以及与环境因子之间的相关性,并进行聚类分析(UPGMA)和主成分分析.结果表明:各性状在种群内和种群间均存在一定变异性.广西花坪自然保护区两个种群(HP1,HP2)枝叶形态性状(尤其是枝)的...     

双菱藻科（硅藻门）——四个中国新纪录种

本文报道了采自新疆及云南地区的双菱藻科（硅藻门）中国新纪录植物4种,分别为耳蜗波缘藻Cymato—pleura cochlea Brun、维苏双菱藻Surirella visurgis Hustedt、盾状马鞍藻Campylodiscus clypeus Ehrenberg和莱温德马鞍藻Campylodiscus levanderi Hustedt。通过光镜（LM）和扫描电镜（SEM）观察,对其分类学特征进行了详细的描述,并介绍了他们的生境特征等。     

果胶酶高产菌株的紫外线及硫酸二乙酯的诱变育种

以HDYM-02为出发菌株,用紫外线及硫酸二乙酯进行诱变,从大量突变株中进行筛选,选育出2株产果胶酶性质稳定且酶活明显提高的突变株UV-21和DES-1,株相比其产酶期提前,前者在24h时的酶活力为出发菌株的1．6倍,后者在12h的酶活力为出发菌株的1．44倍。     

家蚕Bms3a基因真核表达载体的构建及其在家蚕细胞和蚕体中的表达

Bms3a基因可能在家蚕Bombyx mori抗病或细胞凋亡中有一定的作用。将融合有绿色荧光蛋白的Bins3a基因克隆到杆状病毒转移载体pFastBac1中获得了pFastBac-IE1-Bms3a-EGFP真核表达载体,利用杆状病毒(Bac-to-Bac)表达系统筛选重组杆状病毒,以重组病毒感染家蚕BmN细胞和五龄幼虫,分别在感染24h和48h检测到有绿色荧光蛋白的表达,Western blot证明表达的融合蛋白在相对分子量约57kD处出现特异条带,与预计的蛋白理论值相符。结果表明BmS3A-EGFP融合蛋白在家蚕细胞BmN及幼虫体中得到高效表达。研究结果为进一步研究BmS3A蛋白的功能奠定了基础。     

国家自然科学基金资助的生物入侵基础研究概况

基于1999~2010年国家自然科学基金资助项目,分析了我国生物入侵基础研究概况。在这期间,生物入侵领域得到资助的项目数和经费均呈现快速上升的趋势,资助的项目从1999年的3个增加到2010年的69个,资助的经费从1999年的94万元增加到2010年的1838万元。得到资助的项目数在不同学科的分布不均匀,其中,植物保护学科得到资助的项目数为123个,生态学科得到资助的项目数为82个,这2个学科得到资助的项目数占总项目数的67.9%,得到资助的经费占总经费的66.3%。资助项目的主要研究内容涉及22种入侵植物病原微生物、26种入侵动物和24种入侵植物,从中可以透视本领域的研究重点。资助的项目主要集中在华北、华东和华南地区的国家级科研机构和高等院校,这种区域分布格局与我国入侵生物的地理分布格局相吻合。为了进一步推动国家自然科学基金对生物入侵领域各项工作的资助,本文提出了一些合理化的建议。