Hexavalent Chromium Removal by Candida sp. in a Concentric Draft-Tube Airlift Bioreactor

The main purpose of this work was to conduct a kinetic study on cell growth and hexavalent chromium [Cr(VI)] removal by Candida sp. FGSFEP in a concentric draft-tube airlift bioreactor. The yeast was batch-cultivated in a 5.2-l airlift bioreactor containing culture medium with an initial Cr(VI) concentration of 1.5 mM. The maximum specific growth rate of Candida sp. FGSFEP in the airlift bioreactor was 0.0244 h^?1, which was 71.83% higher than that obtained in flasks. The yeast strain was capable of reducing 1.5 mM Cr(VI) completely and exhibited a high volumetric rate [1.64 mg Cr(VI) l^?1 h^?1], specific rate [0.95 mg Cr(VI) g^?1 biomass h^?1] and capacity [44.38 mg Cr(VI) g^?1 biomass] of Cr(VI) reduction in the airlift bioreactor, with values higher than those obtained in flasks. Therefore, culture of Candida sp. FGSFEP in a concentric draft-tube airlift bioreactor could be a promising technological alternative for the aerobic treatment of Cr(VI)-contaminated industrial effluents.     

银杏外种皮综合利用的研究

从银杏外种皮中提取的银杏酚酸和白果酚有杀虫、杀菌作用。银杏酚酸和银杏黄素、银杏异黄素混合物对致病性真菌生长有明显抑制作用 ,且有抗过敏、抗炎等作用。同时测定了银杏外种皮中萜内酯的含量和微量元素、氨基酸、蛋白质的含量。结果表明 :银杏外种皮有综合利用和开发的前景     

Galaxies, human eyes, and artificial neural networks

The quantitative morphological classification of galaxies is important for understanding the origin of type frequency and correlations with environment. However, galaxy morphological classification is still mainly done visually by dedicated individuals, in the spirit of Hubble's original scheme and its modifications. The rapid increase in data on galaxy images at low and high redshift calls for a re-examination of the classification schemes and for automatic methods. Here are shown results from a systematic comparison of the dispersion among human experts classifying a uniformly selected sample of more than 800 digitized galaxy images. These galaxy images were then classified by six of the authors independently. The human classifications are compared with each other and with an automatic classification by an artificial neural network, which replicates the classification by a human expert to the same degree of agreement as that between two human experts.     

Energetics, patterns of interaction strengths, and stability in real ecosystems

Ecologists have long been studying stability in ecosystems by looking at the structuring and the strengths of trophic interactions in community food webs. In a series of real food webs from native and agricultural soils, the strengths of the interactions were found to be patterned in a way that is important to ecosystem stability. The patterning consisted of the simultaneous occurrence of strong "top down" effects at lower trophic levels and strong "bottom up" effects at higher trophic levels. As the patterning resulted directly from the energetic organization of the food webs, the results show that energetics and community structure govern ecosystem stability by imposing stabilizing patterns of interaction strengths.     

香龙血树真菌病害的鉴定

1997-2000年在广州地区的香龙血树[Dracaena fragrans(L.)Ker-Gaw.]种植单位共调查到9种真菌病害，即：可可球二孢茎枯病，顶多毛孢叶斑病，弯孢霉灰斑病，弯孢霉褐斑病，炭疽病，拟盘多毛孢叶斑病，拟茎点霉灰斑病，拟茎点霉叶斑病和球壳孢叶枯病，其病原菌分别被鉴定为：可可球二孢（Botryodiplodia theobromaePat.)、龙血树顶多毛孢（Bartalinia dracaenaeaP.G.Xi,Z.D.JiangetP.K.Chi)，弯孢霉[Gurvularia lunata(Walker)Boedijn]、塞河弯孢霉[Curvularia senegalensis(Speg.)Subram]、围小丛壳[Glomerella cingulata(Stonem)Spauld,etSchrenk]，棒孢拟盘多毛孢[Pestalotiopsis clavispora(Atk)Stey]、龙血树拟茎点霉（phomopsis dracaenae Sahni)，龙血树生拟茎点霉（Phomop-sis dracaenicola Z.D.Jiang,P.G.XietP.K.Chi)，龙血树球壳孢（Sphaeropsis dracaenaeP.G.XietP.K.Chi)，对生产影较大的是由可可球二孢引起的茎枯病和由围小丛壳引起的叶部炭疽病。     

球壳孢目真菌同工酶电泳：Ⅱ.Ascochyta等八属代表种的分析

对球壳孢目8属46个种的代表菌株进行了酯酶等5种同工酶及菌体可溶性蛋白的聚丙烯酰胺凝胶电泳分析，电泳图谱显示，种间区别明显，大多数种具有各自的特征性图式，从聚类分析所得相似性矩阵和树状图可见，属内种间的遗传一致性最高的是Sphaeropsis属性，供试菌株相互的相似性多在50％以上，Ascochyta和Phyllosticta两属内的种也表现出较高的相似性，其他属内的供试种则不能类聚在一起。各属间Macrophoma,Coniothyrium,Sphaeropsis和Phyllosticta四属的菌株可在一定的遗传距离内聚为一类，Ascochyta属与这一类的距离也很近，Phomopsis和Phoma两属的菌株出现交叉相聚现象；Septoria属的菌株则各自独立，与其他类群间的距离也较远。     

苎麻苗期封行期植株营养诊断及调节施肥研究

以“养分指数”为依据对新栽麻和成龄麻苗期、封行期进行植株养分平衡营养诊断,结果表明,各时期养分元素障碍因子对产量与品质的限制程度依次为(1)苗期新栽麻B>Fe>Cu>S,成龄麻N>B>P>Fe>Cu>S;(2)封行期基础肥力较好的土壤上新栽麻Mg,B>Zn>K>Ca,成龄麻Mg,B>Zn>N,P>K>Ca;基础肥力较差的土壤上新栽麻与成龄麻Mg,B>Zn>N,P>K>Ca>     

干旱胁迫下沙棘膜脂过氧化保护体系研究

研究了干旱胁迫下沙棘幼林苗木自由基清除系统活性与沙棘耐旱性的关系.结果表明:长期轻度及中度干旱胁迫下保护酶系统SOD、POD、CAT活性均高于正常水平,重度干旱下3种酶活性均能在胁迫初期随时间延长而上升;抗氧化物质AsA在轻度、中度干旱下高于对照,GSH含量在轻度干旱下含量与对照接近,中度及重度干旱下前、中期随时间延长趋于增加,而后期降低,表明干旱下自由基清除系统活性高,能有效减轻膜脂过氧化伤害,细胞膜透性和MDA含量增加不明显.由于沙棘保护酶体系(SOD、POD、CAT)、抗氧化物质(AsA、GSH)、细胞膜透性和MDA含量增加缓慢,重度干旱下也能在一定时间内保持稳定,这些物质是构成沙棘强耐旱性的内在基础.     

发展农产品快速检测技术确保饮食安全

发展农产品快速检测技术是一项利国利民的大事 ,不仅是保护消费者利益的重大举措 ,也是推进农业结构调整 ,提高农产品市场竞争力 ,增加农民收入的有效措施。建立与国际接轨的农产品及其加工品质量标准体系和检测监督机制、措施 ,进行农产品品质检测重要性的宣传 ,同时认真贯彻执行《中华人民共和国产品质量法》。引进、吸收和消化国外先进的农产品检测技术和设备 ,利用我国农产品生产和加工的人才优势 ,通过政府资助开展农产品检测研究。加速制定有利于无公害食品发展的扶持政策 ,包括对无公害食品的生产、加工、流通等方面的政策扶持 ,确保广大人民吃上放心食品     

刺槐栽培与利用研究概况

概述了国内对刺槐栽培与利用研究的现状，介绍了刺槐的生物学特性、人工栽培技术及开发应用现状。