固定化多酚氧化酶传感器检测酚类化合物研究

用从马铃薯中提纯、经吸附交联得到的固定化多酚氧化酶与氧电极组装设计而成的酚传感器，可检测大多数酚类化合物，其灵敏度，准确度，线性范围，响应速度，稳定性及抗干扰性，均可基本满足要求。研究证明，该法具有一定的开发实用价值。     

人为干扰对小兴安岭森林湿地土壤碳组分和酶活性的影响

以小兴安岭落叶林沼泽湿地为研究对象,对比研究皆伐地、火烧地和落叶松湿地土壤碳组分和酶活性.结果表明:(1)3种湿地类型土壤SOC含量表现为对照地显著高于皆伐地和火烧地(p0.05),在0~10 cm土层中皆伐地与对照地相比降低了58.38%,火烧地与对照地相比降低了61.96%.皆伐地与火烧地在不同土层的土壤中SOC含量差异不显著(p0.05);DOC含量对照地显著高于皆伐地和火烧地(p0.05).在0~10cm土层中火烧地DOC含量是皆伐地的1.99倍,两者差异不显著(p0.05);不同干扰方式对土壤MBC含量影响的差异主要表现在0~10 cm的土层土壤,对照地分别比皆伐地和火烧地高23.13%和95.79%(p0.05).在不同的土层中皆伐地MBC含量均大于火烧地,与SOC含量的变化趋势一致.(2)与对照地相比,皆伐地与火烧地0~10 cm土层的土壤蔗糖酶活性分别降低了45.59%和36.76%,脲酶活性显著降低了18.22%和55.69%(p0.05),蛋白酶活性降低了19.65%和17.34%,淀粉酶活性降低了6.29%和10.69%.土壤碳组分和酶活性在垂直方向上均表现为随着土层深度增加而减小.皆伐和火烧造成森林湿地土壤碳组分和酶活性降低.     

不同粒径羟基磷灰石对污染土壤铜镉磷有效性和酶活性的影响

为研究不同粒径羟基磷灰石对重金属污染土壤的修复效果,采用向污染土壤添加常规磷灰石（150 μm）、微米（3 μm）和纳米（40 nm）羟基磷灰石的田间原位试验方法,考察其钝化修复5 a后对土壤铜镉磷有效性和酶活性的影响.结果表明:3种粒径羟基磷灰石均提高了土壤pH,降低了土壤交换性酸和交换性铝的含量,且微米羟基磷灰石处理效果最好.常规磷灰石、微米和纳米羟基磷灰石处理分别使w（离子交换态铜）降低了62.6%、74.3%和70.4%,w（离子交换态镉）降低了15.7%、25.3%和26.7%.3种材料均增加了土壤w（TP）,其中4.61%~17.4%和73.4%~89.8%分别转化为树脂磷和稳定态磷.微米羟基磷灰石处理分别使土壤脲酶活性和微生物量碳含量提高了4.66和0.66倍.研究显示,微米羟基磷灰石更有利于铜和镉由活性态向非活性态转化,增加土壤磷的有效性,提高土壤微生物活性,在我国南方重金属污染红壤区具有较好的应用潜力.      

锑胁迫下丛枝菌根真菌对玉米生长与锑吸收及抗氧化酶的影响

为了探讨AM(arbuscular mycorrhizal,丛枝菌根)真菌在Sb(锑)胁迫下对农作物生长及吸收Sb的影响,采用盆栽试验研究了在不同Sb添加量[即w(Sb)分别为0、500、1 000 mg/kg]下,接种AM真菌对玉米植株生物量以及N、P和Sb的吸收、膜脂过氧化[MDA(丙二醛)]和抗氧化酶活性的影响.结果表明:随着土壤中Sb添加量的增加,玉米植株的生物量、w(TN)和w(TP)均呈显著下降趋势,植株体内的w(Sb)和Sb积累量、MDA含量、CAT(过氧化氢酶)以及POD(过氧化酶)活性均显著上升.与未接种组相比,接种AM真菌显著促进了玉米植株的生长,提高了玉米植株地上部分的w(TN)和w(TP).在3个Sb添加量处理下,接种显著增加了玉米植株地下部分的w(Sb)、地上和地下部分的Sb积累量以及地上部分的CAT活性,增幅分别为8.90%~23.30%、18.87%~28.37%、27.68%~78.95%及14.92%~88.52%;同时,接种降低了玉米植株中Sb的转运率、玉米植株地上部分的w(Sb)和MDA含量,在1000 mg/kg Sb添加量下差异达显著水平,三者分别降低了36.35%、22.81%和24.29%.研究显示,在Sb污染环境下,接种AM真菌能够减轻玉米植株膜脂过氧化程度,在提高玉米植株地下部分w(Sb)的同时,也会降低Sb向地上部分的转运,减轻Sb对玉米的毒害作用.      

高效酶促进剂Accell在养猪废水处理工艺中的应用研究

为了考察高效酶促进剂在养猪废水处理工艺中的功能,在养猪废水治理工艺的生化段SBR反应器进水中投加高效酶促进剂Accell.两套相同的装置平行运行的效果对比表明:投加Accell可减少剩余污泥的排放量,增加溶氧效率,强化污染物的去除效果;投加高效酶的装置对COD的去除可在SBR反应器基础上再减少40%以上,对NH3-N的去除可进一步再减少25%以上,对P的去除也有一定的促进作用.     

氯灭活地下水源中3种优势真菌的效能与机制

地下水源中真菌大量繁殖会产生嗅味,引发毒性反应以及产生大量肉眼可见的絮状物,严重影响供水水质.以地下水源中3种优势真菌木霉属、青霉属、枝孢属为研究对象,以氯为消毒剂,通过研究真菌孢子胞内物质泄漏,胞外三磷酸腺苷(ATP),脱氧核糖核酸(DNA)和蛋白质增加及孢子形态变化,探明了氯灭活3种真菌孢子的效能与机制.结果表明,氯灭活真菌孢子符合一级动力学,满足Chick模型,3种真菌的耐氯性为:木霉属青霉属枝孢属,真菌孢子尺寸越大,亲水性越强,灭活效果越好.氯灭活后,胞内物质泄漏,胞外特征物质(ATP、DNA、蛋白质)显著增加;氯对细胞表面破坏严重,灭活后真菌孢子凹陷,表面褶皱.综上所述,氯首先作用于孢子表面,降低孢子的可培养性,进一步作用使细胞的通透性屏障受损,导致胞内特征物质释放,以致孢子死亡.     

Overexpression of NADH oxidase gene from Deinococcus geothermalis in Escherichia coli

When using stable enzyme genes from a thermophile to create a biosensor in Escherichia coli, it is vital that these genes be overexpressed in order to provide a sufficient supply of enzymes. In this study, overexpression of the NADH oxidase (Nox) gene from the thermophile Deinococcus geothermalis was successfully achieved with the aim of creating a stable biosensor active at room temperatures. To do so, modification of 10 nucleotides, GAAATTAACT, upstream of the start codon of the Nox gene was necessary.     

Overexpression of NADH oxidase gene from Deinococcus geothermalis in Escherichia coli

When using stable enzyme genes from a thermophile to create a biosensor in Escherichia coli, it is vital that these genes be overexpressed in order to provide a sufficient supply of enzymes. In this study, overexpression of the NADH oxidase (Nox) gene from the thermophile Deinococcus geothermalis was successfully achieved with the aim of creating a stable biosensor active at room temperatures. To do so, modification of 10 nucleotides, GAAATTAACT, upstream of the start codon of the Nox gene was necessary.     

Soil microbial community structure and function responses to successive planting of Eucalyptus

Many studies have shown soil degradation after the conversion of native forests to exotic Eucalyptus plantations. However, few studies have investigated the long-term impacts of short-rotation forestry practices on soil microorganisms. The impacts of Eucalyptus successive rotations on soil microbial communities were evaluated by comparing phospholipid fatty acid （PLFA） abundances, compositions, and enzyme activities of native Pinus massoniana plantations and adjacent 1st, 2nd, 3rd, 4th generation Eucalyptus plantations. The conversion from P. massoniana to Eucalyptus plantations significantly decreased soil microbial community size and enzyme activities, and increased microbial physiological stress. However, the PLFA abundances formed ＂U＂ shaped quadratic functions with Eucalyptus plantation age. Alternatively, physiological stress biomarkers, the ratios of monounsaturated to saturated fatty acid and Gram＋ to Gram- bacteria, formed ＂∩＂ shaped quadratic functions, and the ratio of cy17：0 to 16： 1ω7c decreased with plantation age. The activities of phenol oxidase, peroxidase, and acid phosphatase increased with Eucalyptus plantation age, while the cellobiobydrolase activity formed ＂U＂ shaped quadratic functions. Soil N：P, alkaline hydrolytic nitrogen, soil organic carbon, and understory cover largely explained the variation in PLFA profiles while soil N：P, alkaline hydrolytic nitrogen, and understory cover explained most of the variability in enzyme activity. In conclusion, soil microbial structure and function under Eucalyptus plantations were strongly impacted by plantation age. Most of the changes could be explained by altered soil resource availability and understory cover associated with successive planting of Eucalyptus. Our results highlight the importance of plantation age for assessing the impacts of plantation conversion as well as the importance of reducing disturbance for plantation management.     

丛枝菌对转Bt基因棉根际土壤营养物质及酶活性的影响

转Bt基因抗虫棉已在全球范围内广泛种植,然而Bt棉根际分泌物是否会影响土壤理化性质及土壤功能尚缺乏深入研究。通过盆栽实验方法,设计不同的棉花品种与是否接种丛枝菌总共4个处理,以此研究Bt棉和接种丛枝菌根真菌对植物根际土壤营养物质含量以及土壤酶活性的影响。结果显示:丛枝菌可以使non-Bt棉和Bt棉根际土壤营养物质中的土壤有机质和土壤总氮含量显著增加,但是对根际土壤全磷却鲜有影响。转基因对于不同品种棉花根际土壤酶,丛枝菌均能有效增强其活性。由此表明,丛枝菌对Bt棉和non-Br棉根际土壤环境均具有改善作用。