甲基一六O五降解菌J5的分离及其降解性状研究

从农药厂污水处理系统中分离到 1株降解甲基一六O五 (O ,O-二甲基 -O- 对硝基苯基 -硫代磷酸酯 ,简称MP)的芽胞杆菌 ,初步鉴定为蜡状芽胞杆菌 (Bacilluscereus)J5。J5能够高效降解MP ,但它不能利用MP作为唯一碳源生长 ,其代谢方式可能为共代谢。在有葡萄糖作为碳源的条件下 ,J5可以高效转化MP ,其转化效率可达 95 %以上。用薄层层析、紫外扫描和液相色谱法初步研究了J5对MP的降解性能及相关降解产物     

甲基一六○五降解菌J5的分离及其降解性状研究

从农药厂污水处理系统中分离到1株降解甲基一六○五（0，0－二甲基－0－对硝基苯基－硫代磷酸酯，简称MP）的芽胞杆菌，初步鉴定为蜡状芽胞杆菌（Bacillus cereus）J5。J5能够高效降解MP，但它不能利用MP作为唯一碳源生长，其代谢方式可能共代谢。在有葡萄糖作为碳源的条件下，J5可以高效转化MP，其转化效率可达95％以上。用薄层层析、紫外扫描和液相色谱法初步研究了J5对MP的降解性能及相关解产物。     

施氏假单胞菌N2代谢邻/间/对甲酚的特性研究

本论文以施氏假单胞菌N2为受试菌株,研究了N2菌对邻/间/对甲酚及其混合物的生物降解特性.结果表明,N2菌能以邻/间/对甲酚为唯一碳源和能源生长,但对3种异构体的降解速率各异.完全降解600 mg·L~(-1)的对甲酚仅需6 h,间甲酚则需24 h,但对邻甲酚的降解明显减缓;200 mg·L~(-1)邻甲酚48 h的降解率仅为11.38%.GC-MS结果分析发现,N2菌代谢甲酚途径主要为甲基氧化、芳环羟化,随后脱羧、开环裂解、降解转化至矿化,但3种甲酚的降解途径及酸性代谢产物的形成次序不一致.3种甲酚混合存在时可促进N2菌对其降解,这主要是因为混合碳源的协同作用减少了体系中因产酸过多引起的毒性,从而促进了N2菌对甲酚的降解矿化.     

嗜铁细菌枯草芽胞杆菌Bs-15对辛硫磷的降解特性

为探讨嗜铁细菌对农药辛硫磷的降解及其土壤修复的潜能,采用改良定向培育法,对嗜铁细菌枯草芽胞杆菌(Bacillus subtilis)Bs-15进行驯化,摸索其降解条件,并测定其土壤修复能力.结果显示,菌株Bs-15对辛硫磷有较高的耐受性,在辛硫磷浓度达到800 mg L-1时仍可生长;可以以辛硫磷为唯一碳源生长,适合其降解的最佳外加营养物质为酵母粉,无机盐为MgCl2.最适辛硫磷降解浓度为≤100 mg L-1,浓度继续升高时降解效能明显降低;最适降解温度为35℃;对pH值有较广的适应范围,在pH 5-9时降解率较高;最适降解时间为24 h,振荡速率为150 r min-1,接种量为8%;土壤修复试验表明,此菌株在第20天时对土壤中辛硫磷的降解率接近50%.本研究结果说明枯草芽胞杆Bs-15对辛硫磷具有较好的降解作用,对辛硫磷污染的土壤具有良好的修复潜能.     

两种启动子对聚γ-谷氨酸降解酶基因在地衣芽胞杆菌中的加强表达效果

聚γ-谷氨酸(γ-PGA)是一种应用前景良好的生物高分子材料.比较了蔗糖诱导的枯草芽胞杆菌果聚糖蔗糖酶基因(SacB)启动子和地衣芽胞杆菌α-淀粉酶基因启动子对γ-PGA降解酶基因ywtD在地衣芽胞杆菌中加强表达的影响.分别用SacB基因启动子和α-淀粉酶启动子构建了穿梭表达载体pHY300-SYT和pHY300-PYT,通过电转化地衣芽胞杆菌WX-02获得重组子SYT和PYT.酶活测定结果显示SYT和PYT中γ-PGA降解酶基因ywtD得到加强表达,摇瓶发酵结果显示两个重组菌株的γ-PGA相对分子质量都由1 000 000~1 200 000降低为800 000~900 000,PYT的γ-PGA产量较对照菌株PLK提高了33%,由13.50 g L-1提高到17.97 g L-1,而SYT的γ-PGA产量则降低为10.85 g L-1.因此,α-淀粉酶启动子更适合于在地衣芽胞杆菌WX-02菌株中表达γ-PGA降解酶基因,从而获得高产低分子量γ-PGA的工程菌.     

焦化厂污染土壤中多环芳烃降解菌的分离及降解特性

分别以芴(3环)、荧蒽(4环)和苯并[b]荧蒽(5环)为唯一碳源(1 mg/L),采用平板划线法对某焦化厂污染土壤中的多环芳烃降解菌进行分离.通过自制的呼吸器,研究所得多环芳烃降解菌对14C-菲(5μL/100 mL 40~60 mCi/mmol)的矿化情况;通过序批试验,以煤焦油为碳源(1μL/mL),研究这些菌对19种多环芳烃的降解情况.多次划分后,得到4种菌,经鉴定命名为博特氏菌L1、苍白杆菌L1、微杆菌L1和赤红球菌L1.经过3周的矿化实验,微杆菌L1可以将14C-菲全部矿化成14CO2,赤红球菌L1可将大约60%的14C-菲矿化成14CO2,而博德特氏菌L1和苍白杆菌L1对14C-菲无矿化作用.经过5周的降解实验,博德特氏菌L1对大多数多环芳烃表现了良好的降解作用,苍白杆菌L1和微杆菌L1对部分多环芳烃有降解作用,而赤红球菌L1培养系统中某些多环芳烃的浓度甚至有增大,这可能与其在代谢过程中产生表面活性物质有关.所得4种菌在焦化厂污染土壤的微生物修复中具有较大的应用潜力.图3表1参27     

一株降解苄嘧磺隆光合细菌的分离鉴定及其降解特性

从农药厂工业废水和污泥中富集分离到一株能降解苄嘧磺隆(Bensulfuron methyl)的光合细菌PSB07-6,根据分离菌株的细胞形态结构、活细胞光吸收特征、生理生化特征以及系统发育分析将该菌初步鉴定为沼泽红假单胞菌(Rhodopseudomonas palustris).高效液相色谱法(HPLC)测定该菌降解光合细菌培养基中苄嘧磺隆的能力,在pH为6.5的光合细菌培养基中培养5 d,对350 mg·L-1苄嘧磺隆降解率达25.03%.添加回收率为105%～112%.降解特性研究结果表明,该菌能以苄嘧磺隆为唯一碳源和氮源,降解最佳条件为30℃、pH6.5.     

葡萄糖对芽孢杆菌降解水体中4,4'-二溴联苯醚的促进作用

为了探究4,4'二溴联苯醚(BDE-15)在水环境中的生物降解过程及其影响因素,在实验室内利用筛选得到的芽孢杆菌(Bacillus sp.)对BDE-15进行生物降解试验,并研究了外加碳源和高初始浓度BDE-15对微生物降解能力的影响.结果表明,在葡萄糖作为外加碳源条件下芽孢杆菌能降解水体中BDE-15,4d后菌株对BDE-15的降解率为28％,再次添加葡萄糖可提高降解率至55％.高质量浓度(50 mg·L-1)BDE-15能抑制芽孢杆菌生长,并显著影响菌株对BDE-15的降解能力.     

杀草丹降解菌Bacillus sp. T2的筛选、鉴定及降解特性

为研发稻田除稗剂杀草丹污染环境的生物修复技术和探究杀草丹微生物降解代谢机制,通过微生物驯化与富集技术,从长期施用杀草丹水稻田土样中分离纯化一株能够以杀草丹为唯一碳源生长的高效降解菌株T2,在36 h内对0.4 mmol/L的杀草丹降解率达到98.3%以上.根据其形态、生理生化特征及16S rRNA基因序列相似性分析,将其初步鉴定为芽孢杆菌属(Bacillus sp.T2).通过GC-MS鉴定产物为对氯苄硫醇、对氯苯甲醛和对氯苯甲酸;依据产物鉴定结果推测菌株T2通过硫酯键水解的方式起始杀草丹的降解,首先将其转化为对氯苄硫醇,随后进一步被氧化为对氯苯甲醛和对氯苯甲酸,该降解途径可能是一种新的杀草丹微生物降解代谢途径.因此菌株Bacillus sp.T2对杀草丹具有非常高的降解效率,在污染环境的微生物修复方面具有很好的应用前景;本研究结果也为揭示土壤中杀草丹微生物降解代谢过程及机制提供了研究材料和理论依据.     

苏云金芽胞杆菌生物活性成分研究进展

自1901年Ishimata从家蚕(Bambyx mori)中分离出第1株苏云金芽胞杆菌淬倒亚种(Bacillus thuringiensis subsp.sotto)以来,对苏云金芽胞杆菌研究已有百年的历史.现在国际上确认的苏云金芽胞杆菌菌株已有69个血清型[6],近40000株. 由于苏云金芽胞杆菌的巨大经济利益,不断地引起了广大科研人员和产品开发商的极大兴趣.到目前为止,科学家们已     

Observations on the function of the glands of the foot of the pediveliger of Ostrea edulis during settlement

The use during settlement of secretions of the 9 different types of gland in the foot of the pediveliger of Ostrea edulis L. was examined experimentally. During settlement, there is a progressive decrease in the crawling speed of the larva and a strengthening of its bond with the substratum. Both changes are related to (a) a change from ciliary to muscular pedal locomotion; (b) the increasing acidity and viscosity of the mucoid secretions used; (c) the secretion of a byssus thread by the glands of the byssus duet; (d) changes in the form and composition of this byssus. At the termination of settlement, the entire contents of 2 types of gland are discharged. Their secretions give rise to the cement which permanently fixes the larva to the substratum. The 9 types of gland are utilised sequentially in a manner closely related to the 6 phases recognised in settlement behaviour.     

On the behaviour of the residence time at the bottom of the mixed layer

To understand why the findings of Deleersnijder et al. [(2006), Environ Fluid Mech 6: 25–42]—the residence time in the mixed layer in not necessarily zero at the pycnocline—are consistent with those of Delhez and Deleersnijder [(2006), Ocean Dyn 56:139–150]—the residence time in a control domain vanishes at the open boundaries of this control domain—, it is necessary to consider a control domain that includes part of the pycnocline, in which the eddy diffusivity is assumed to be zero. Then, depending on the behaviour of the eddy diffusivity near the bottom of the mixed layer, the residence time may be seen to exhibit a discontinuity at the interface between the mixed layer and the pycnocline. If such a discontinuity exists, the residence time is non-zero in the former and zero in the latter. This is illustrated by analytical solutions obtained under the assumption that the eddy diffusivity is constant in the mixed layer.     

豪猪消化系统的解剖研究

为了了解豪猪的消化生理,为豪猪的人工饲养技术研究提供基础依据,以达到高效饲养豪猪的目的,笔者对豪猪的消化器官进行了系统解剖研究.结果表明:豪猪的胃为单室胃.盲肠很发达,这与其能够消化植物纤维有关.豪猪肝脏很发达,其重量为402 g,是其体重的4.59%,肝脏分叶多而明显.     

刍议医院资产管理的现状及其对策

医院的固定资产和流动资产是医院赖以生存和发展的基础,是一项非经营性国有资产．目前公立医院固定资产、流动资产管理现状不容乐观,针对这种状况,首先分析问题形成的原因,然后提出管理的措施或建议,从而使资产管理工作规范化、制度化、科学化,使有限的卫生资源发挥出最大的社会效益和经济效益．参3．     

Mining of the forest and the time path of the price of timber

The paper analyzes the effect of transportation (site specific) costs and the effect of mining (depletion) of the forest on the time path of the price and of the net price of timber in two forestry models. The models differ in that one has zero costs and the other has positive costs. The analyses yield the standard mining theory results for certain cases. They also yield extentions of these results for cases with growth of the harvested trees and/or regeneration on the harvested land. The paper concludes, as one would expect, that the theory of the mine is useful in analyzing the time path of the price of timber.     

Adjusting the economy to the new energy realities of the second half of the age of oil

Our research indicates that, due to the depletion of conventional, and hence cheap, crude oil supplies (i.e. peak oil), increasing the supply of oil in the future would require exploiting lower quality resources (i.e. expensive), and thus will most likely occur only at high prices. This situation creates a system of feedbacks where economic growth, which requires more oil, would require high oil prices that will undermine that economic growth. We conclude that the economic growth of the past 40 years is unlikely to continue unless there is some remarkable change in how we manage our economy.     

Splitting the tail of the displacement kernel shows the unimportance of kurtosis

Animals disperse in space through different movement behaviors, resulting in different displacement distances. This is often described with a displacement kernel where the long-distance dispersers are within the tail of the kernel. A displacement with a large proportion of long-distance dispersers may have impact on different aspects of spatial ecology such as invasion speed, population persistence, and distribution. It is, however, unclear whether the kurtosis of the kernel plays a major role since a fatter tail also influences the variance of the kernel. We modeled displacement in landscapes with different amounts and configurations of habitats and handled kurtosis and variance separately to study how these affected population distribution and transition time. We conclude that kurtosis is not important for any of these aspects of spatial ecology. The variance of the kernel, on the other hand, was of great importance to both population distribution and transition time. We argue that separating variance and kurtosis can cast new light on the way in which long-distance dispersers are important in ecological processes. Consequences for empirical studies are discussed.     

Stimulation of fat-body production in the polyps of the coralPocillopora damicornis by the presence of mutualistic crabs of the genusTrapezia

A mutualism exists between the xanthid crabs of the genusTrapezia and their host corals,Pocillopora damicornis. It has previously been established that these obligate coral residents benefit the coral hosts by defending them against echinoderm predators and by increasing the survival of polyps located deep between the coral branches. In turn, the corals apparently benefit the crabs by producing lipid-filled structures on which the trapezid crabs feed; these fat bodies may contain some of the lipid which in previous studies of coral metabolism has been termed excess. It was determined by experiments conducted at the Hawaii Institute of Marine Biology that the presence of crabs in colonies ofP. damicornis stimulates the polyps to produce the lipid-filled fat bodies; removal of crabs causes corals to cease producing fat bodies. A structure very similar to the fat bodies ofP. damicornis has been reported inAcropora durvillei. Both of these coral genera ordinarily possess xanthid-crab mutualists. This association between branching corals and crustaceans may have evolved because corals of these genera provide shelter among their branches and because these shallow-water corals are evidently capable of releasing lipid which is excess to the corals' metabolic needs, but which can be utilized by the crabs.     

三峡库区消落带土壤中铅污染调查

报道了三峡库区长江干流及小江支流消落带土壤中重金属铅含量背景值的调查结果。结果表明，目前土壤未被重金属铅污染。