降解乙酰甲胺磷农药的芽孢杆菌分离鉴定与降解性能分析

[目的]探究微生物对农药乙酰甲胺磷的生物降解作用。[方法]利用筛选培养基从土壤中分离乙酰甲胺磷降解性菌株,对其中一株降解性能较好的菌株YJ1进行分析,扩增菌株16S r DNA,测序并构建系统演化树,结合生理生化性质,初步确定其分类地位,并检测该菌株对乙酰甲胺磷的降解性能。[结果]乙酰甲胺磷降解菌株YJ1属于芽孢杆菌属,可以在乙酰甲胺磷为唯一碳源的环境中存活;该菌株在乙酰甲胺磷含量为1 200 mg/L的培养基中生长良好;在p H7~10碱性条件下,该菌株在乙酰甲胺磷液体培养基中生长较好,酸性条件不利于其生长;该菌株在72 h对乙酰甲胺磷降解率可达100%,具有很高的乙酰甲胺磷降解活性。[结论]所发现的芽孢杆菌YJ1可用于乙酰甲胺磷的生物降解。     

敌敌畏降解菌的分离鉴定及降解特性研究

目的:从受有机磷农药污染的土壤中分离能降解DDVP的菌株,对其进行鉴定和降解特性研究.方法:采用DDVP为惟一碳源和能源的无机盐培养基,通过富集培养、平板划线分离得到一株优势菌,编号为DDW-1,采用形态学、生理生化和16S-rDNA序列分析对其进行鉴定,采用气相色谱测定菌株DDW-1对DDVP的降解能力,并进行底物广谱性测试和降解酶定位实验.结果:该菌株鉴定为甲基杆菌属(Methylobacterium sp.).降解特性试验结果表明,其最佳生长条件为温度28℃,初始pH为7.0,在该条件下,500mg·L-> DDVP经过DDW-1菌株代谢3d后,降解率达63.7%.结论:菌株DDW-1能降解DDVP,该菌株产胞内酶.     

氯氰菊酯降解菌草酸青霉SSCL-5分离鉴定及降解特性

为解决土壤中残留的菊酯类农药问题,通过富集筛选法从70余份土壤中获得一株高效分解利用菊酯类农药的微生物菌株SSCL-5,该菌株可在含1 000 mg/L的氯氰菊酯无机盐培养基中正常生长。经形态学及ITS测序鉴定,确定该菌为草酸青霉(Penicillium oxalicum),对多种高浓度菊酯类农药耐受。经紫外分光光度法及HPLC验证该菌株草酸青霉SSCL-5在无机盐培养基、28℃、180 r/min摇瓶培养24 h的条件下,对400 mg/L氯氰菊酯的降解率为97%。土壤室内试验证明该菌在土壤中,温度20-34℃、水分含量保藏40%-60%条件下,30 d可将土壤中400 mg/L的氯氰菊酯降解67.6%。     

低温萘降解菌的筛选、鉴定及降解条件优化

研究采用富集培养法从黑龙江省大庆油田地区污染土壤中筛选能以萘为唯一碳源和能源的低温菌株,采用气相色谱-质谱法(GC-MS)研究降解菌在萘-无机盐培养基中对萘的降解情况,通过单因素试验与正交试验测定降解菌的培养条件并进行优化,同时分析降解阶段其主控因素。结果表明:筛选出2株在低温条件下高效降解萘的菌株,编号为GN1和GN2。在低温条件下GN1和GN2可以快速降解萘,在对照组非生物因素影响基础上,萘(300 mg/L)的降解率在4 d内达到94.43%和95.47%,在耐受能力和降解速度方面具明显优势;经形态观察、生理生化特性和16S rDNA基因序列鉴定两株降解菌皆属于假单胞菌属(Pseudomonas);均在萘-无机盐培养基(萘浓度300 mg/L),培养温度15℃,初始pH 6.0,培养转数180 r/min,培养时间7 d的条件下生长最佳。2株降解菌的生长与5种环境因素均有显著关系。     

芘高效降解菌的分离鉴定及其降解特性的研究

以芘为惟一碳源.采用寓集培养方法,从沈抚灌区石油污染土壤中分离得到一株芘降解菌B05.根据形态学观察、生理牛化鉴定和16S rDNA序列分析结果.将菌株B05鉴定为Aminobacter ciceronei.在芘初始浓度为1mg/L的液体无机盐培养基中,培养10d,菌株B05对芘的降解率为51%;在芘初始浓度为1mg/kg的土壤培养基条件下,培养30d,菌株B05对芘的降解率可达51%;在芘初始浓度为50mg/L的乙醇液体培养基条件下,培养5d,菌株B05对芘的降解率可达25.9%.对菌株培养条件进行优化,经SlideWrite统计软件拟合,菌株B05在牛肉膏蛋白胨液体培养基上的最适生长pH值为7.3,最适生长温度为32.5℃,最适装液量为25.4mL(150mL三角瓶).     

甲胺磷降解细菌的分离鉴定及其降解效能的研究

从土壤中分离筛选获得两株对甲胺磷农药有较强降解效能的细菌,经鉴定分别为头状葡萄球菌(Staphylococcus capitis)(称为D菌)和粪产碱菌(Alcaligenes faecalis)(称为J菌)。D菌和J菌在甲胺磷浓度为500mg.L-1,30℃,180r.min-1摇床上用基础培养基中培养72h,对甲胺磷的降解率分别达到58.49%和65.80%。D菌和J菌混合培养可提高对甲胺磷的降解效能,对甲胺磷72h的降解率达到72.93%。     

1株四环素降解菌的分离鉴定及降解特性研究

应用微生物降解四环素具有经济有效和环境友好特点,已成为当前研究的热点。采用选择性培养基,从鸡粪中分离出1株能以四环素作为唯一碳源生长的菌株TC-1,培养7 d降解率为56.2%,初步鉴定为蜡状芽胞杆菌(Bacillus cereus)。从碳氮源组合、培养基初始pH、Na Cl浓度和装液量四方面研究了TC-1降解四环素的特性。结果表明,TC-1在以葡萄糖和酵母粉为碳、氮源生长时效果最优,培养7 d时OD600达2.17;但最优降解率出现在蔗糖和大豆蛋白胨的碳氮源组合中,为46.8%。当培养基初始pH为7时,菌株TC-1生长最好,OD600为0.44,四环素降解率为92.3%。当培养基中Na Cl浓度达15 g/L时,TC-1生长受到抑制,降解率仅为28.6%;培养基装液量为40%时降解率最高,为56.2%。     

多菌灵降解菌的生物学特性及降解能力研究

农药污染已成为影响人身健康及环境的主要原因。在污染土壤中引入降解特定农药的微生物可有效降低该农药的浓度,并且该方法绿色环保、无二次污染。为降低棚室土壤中的残留农药多菌灵,通过唯一碳源平板筛选法,从长期使用多菌灵的棚室土壤中分离筛选出一株分解利用多菌灵的微生物菌株WNP-3,该菌株可在含200 mg/L的多菌灵LB培养基中正常生长。经形态学、理化、Biolog及16S rDNA鉴定,确定该菌为小麦苍白杆菌(Ochrobactrum tritici)。该菌表现出宽泛的生长范围:在pH4-9,盐含量1%-3%条件下正常生长,对多种农药具有耐受性。经紫外分光光度法及HPLC验证WNP-3在无机盐培养基、28℃、180r/min摇瓶培养120 h的条件下,对100 mg/L多菌灵的降解率为61%。     

全氟辛烷磺酸降解菌的分离与鉴定

目的筛选和分离降解全氟辛烷磺酸(PFOS)的细菌,并进行初步鉴定和降解效率分析。方法采集全氟化工厂周边土壤,利用PFOS为唯一碳源的无机盐培养基进行驯化和富集培养,分离降解PFOS的细菌;通过形态观察、生理生化特性检测和基于16SrRNA基因序列的系统发育分析对分离菌株进行鉴定;采用GC-MS检测其降解PFOS的能力。结果分离获得3株能降解PFOS的细菌YSB1、YSB2和YSB3,初步鉴定分属于鞘酯菌属(Sphingobiumsp.)、中华根瘤菌属(Sinorhizobiumsp.)和苍白杆菌属(Ochrobactrumsp.)。菌株YSB1、YSB2和YSB3在以PFOS为唯一碳源生长的无机盐培养基中生长良好,其对PFOS最大降解率分别为18.4%、10.1%和14.1%。结论自然界存在较丰富的降解持久性有机污染物PFOS的微生物资源。     

高效降解石油外生菌根真菌的室内筛选

对7个外生菌根真菌菌株在不同石油浓度培养基中的生长及其对石油的降解作用进行了研究。结果表明:(1)不同菌株在同一石油浓度培养基中生长速度不同,同一菌株在不同石油浓度培养基中的生长速度亦不同。菌株010和菌株025在不同石油浓度培养基中生长速度均较其他菌株快。菌株010的菌丝干重随着石油浓度的增加而增加,当石油质量浓度为500 mg/L时,菌丝干重达到最大值,高于对照5.27%,石油对其生长产生了促进作用;当石油质量浓度为700 mg/L时,菌丝干重低于对照,随着石油质量浓度的升高,菌株生长呈下降趋势。石油质量浓度为100 mg/L时,菌株025生长最慢,菌丝干重低于对照9.1%。随着石油浓度的增加,菌株生长加快,当石油质量浓度为500 mg/L时,菌丝干重高于对照;当石油质量浓度为700 mg/L时,菌株025菌丝干重最高,高于对照25.65%。随着石油浓度的再度升高,菌株生长呈下降趋势。(2)不同菌株在同一石油浓度下对石油的降解能力不同,同一菌株在不同石油浓度下对石油的降解能力亦不同。菌株025对石油的降解能力最强,对石油的降解能力随着石油浓度的升高而提高。当培养基中石油质量浓度为900 mg/L时,菌株025对石油的降解率最高,达到73.65%。(3)菌株0100、09、035、LH004的菌丝生物量与对石油的降解能力呈正相关。     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.