微生物絮凝剂的稳定性及其对城市污水厂浓缩污泥的絮凝脱水

研究了酱油曲霉(Aspergillus sojae)产生的微生物絮凝剂(MBF)的稳定性, 并将其用于城市污水厂的浓缩污泥的强化脱水。结果表明：由酱油曲霉提取的MBF具有很好的热稳定性和酸碱稳定性, 4℃低温条件下保存35 d后絮凝率仍在96%以上, 而常温条件下保存35 d后不同pH的MBF絮凝率差别很大。与PAM、PAC相比较, MBF能更好地降低城市污水处理厂浓缩污泥比阻。MBF对浓缩污泥的强化脱水的最佳投加量为7%(V/V), 且MBF的单耗随着污泥处理量的增大而逐渐减小。     

高效微生物絮凝剂产生菌TJ-3的絮凝特性分析

从活性污泥中分离筛选出一株高效絮凝剂产生菌TJ-3, 经生理生化试验检测其属于革兰氏阴性菌, 短杆状, 16S rDNA测序鉴定为铜绿假单胞菌。生长曲线表明, TJ-3的生长稳定期较长, 所产微生物絮凝剂(MBF)的稳定性良好。TJ-3产MBF对高岭土悬液具有良好的絮凝效果, 最佳条件下的絮凝率为98.2%。絮凝活性分布实验结果表明, TJ-3所产MBF的活性物质大部分存在于离心后的沉淀物中。处理100 mL高岭土悬液, pH值8.5、1%(质量分数)CaCl2溶液投加量3.5 mL、菌液投加量1.5 mL时, 絮凝效果最佳。     

利用污泥提取液制备微生物絮凝剂

以污水厂剩余污泥作为培养基原料,经过一系列处理,探索微生物絮凝剂产生菌的最适发酵培养基配方,结果表明,污泥预处理条件以pH 12碱解条件最优,碳氮源产出量最大,补加8 g/L葡萄糖后灭菌,微生物絮凝剂产生菌LLin6可正常产絮,絮凝率达91.55%。该结果为降低微生物絮凝剂的制备成本,并实现污泥的减量化和污泥资源化利用提供了基础。     

红平红球菌絮凝基因提取及絮凝剂对血红素肽-铁絮凝特性

优化了红平红球菌(Rhodococcus erythropolis)絮凝基因(NOC-1)的提取条件,探讨了该菌种发酵产生的微生物絮凝荆(MBF)对猪血红蛋白酶解的主要产物-血红素肽铁的絮凝特性.结果表明:采用溶菌酶与CTAB相结合方法,在水浴温度为65℃,时间为20 min条件下,提取絮凝基因,获得了清晰平整明亮的DNA条带,无明显弥散,DNA提取量多且断裂少,利用PCR扩增出了产絮凝基因(NOC-1)16S rRNA,测定并分析了产絮凝基因片段的1400 bp碱基组成.该MBF对猪血红蛋白酶解主要产物,即血红素肽铁絮凝特性与溶液的pH、温度、絮凝方式等有关,当猪血红蛋白酶解溶液pH值为6.0,絮凝温度45℃,结合超声波处理,MBF对血红素肽铁的絮凝率达到最佳,且絮凝沉降规律为拥挤沉淀,絮凝杌理为该菌种产生的MBF为粘多糖,分子上的活性基团(羧基、羟基、氨基等)借助离子键、氢键和范德华力,吸附血红素肽铁形成微粒,并通过架桥方式将2个或更多的微粒交联在一起从而导致絮凝.     

微生物絮凝剂处理废水的研究和发展趋势

概括了微生物絮凝剂及其产生菌的研究成果,重点阐述了微生物絮凝剂在处理高浓度废水、废水脱色、废水除浊、废水除油、污泥脱水和污泥改性等方面的研究现状,并指出研究中存在的问题。同时,提出微生物絮凝剂在废水处理领域的发展趋势和实现规模化生产的研究重点。     

微生物絮凝剂产生菌固定化条件的优化

采用多种固定化方法及载体,进行了微生物絮凝剂产生菌M09固定化方法及条件的研究,并对其所产絮凝剂在不同存储条件下絮凝活性的稳定性进行探讨。结果表明,选用粒径为0.5 cm×0.5 cm×0.5 cm的多孔聚氨酯泡沫为固定化载体,4 g/L的固液比,使用初始蔗糖浓度为2%,NaNO3为0.4%的培养基,28℃振荡培养60 h可获得较高活性的固定化细胞,发酵上清液能够保持较高的絮凝率。研究还发现,在室温条件下,利用此工艺所产高絮凝活性发酵液在含有菌体的反应器内自然静置,发酵液絮凝率仍可缓慢持续上升,维持较高水平达数日,具有较高的稳定性。     

提高唾液酸分泌量对克雷伯氏菌NIII2高产高活性糖蛋白絮凝剂的影响作用

探究克雷伯氏菌NⅢ_2发酵产微生物絮凝剂(MBF)过程中提高唾液酸(SA)分泌量对其高产高活性糖蛋白絮凝剂的影响作用。采用摇瓶发酵,产物冻干后称重,利用高岭土悬浊液测定其絮凝活性,并利用酶标仪测定唾液酸量,从而得出相应结果。研究发现在一定范围内,SA分泌量越高,絮凝剂产量及其活性也会越高。当MBF中SA含量约为12 ng/g MBF时,MBF产量约为12 g/L。在SA分泌量提高的同时,MBF中蛋白质含量和Zeta电位值也得到提高。探索出一种能最大程度提高SA分泌量和MBF产量的三碳源发酵体系:m蔗糖:m丙酮酸钠:m柠檬酸钠=20 g:4 g:2 g,此时MBF的产量为13.85 g/L,蛋白含量为0.41 g/g MBF,絮凝活性为98%。研究结果为高产高活MBF的发酵以及工业化生产提供了可能。     

微生物絮凝剂产生菌的筛选及其培养条件优化

从广西大学食用菌废弃料中分离出7株絮凝剂产生菌,以发酵液对高岭土悬浮液絮凝效果为指标衡量其絮凝活性及产絮凝剂能力,经过初筛与复筛,筛选到一株絮凝剂高产菌F00,初步确定属曲霉属(Aspergillus),并对其产生絮凝剂的条件进行优化.     

辽东栎种子的顽拗性——脱水和低温敏感性

该文采用硅胶(快速脱水)和35℃电子恒温干燥箱中脱水(缓慢脱水)、冷藏(4℃)和冻藏(-4℃)的方法,研究了辽东栎种子的脱水和低温敏感性及其对种子萌发的影响。结果表明:辽东栎种子成熟散落时具有较高的含水量(96.0%)和萌发率(78.9%),无论是快速脱水还是缓慢脱水,萌发率、萌发速率、萌发指数和活力指数均随着脱水时间的延长和含水量的降低呈现减小的趋势,至脱水96 h后(快速和缓慢脱水种子含水量分别为66.0%和69.8%),种子全部失去活力。辽东栎种子活力与含水量呈显著的正相关关系,但轻度脱水可促进种子萌发,快速脱水种子比缓慢脱水种子具有更高的脱水耐性。辽东栎种子不能耐受低温贮藏,萌发率、萌发速率、萌发指数和活力指数在4℃下冷藏30 d或-4℃下冻藏6 h后均显著降低,冷藏90 d或冻藏48 h后种子全部丧失活力。     

脱水污泥中脱色偶氮染料功能菌群的驯化分离

【目的】获得降解混合偶氮染料的高效降解菌,应用于印染行业偶氮染料废水的生物处理和资源化。【方法】以某污水处理厂的脱水污泥作为分离源,经偶氮染料废水驯化后,分离筛选出9株偶氮染料脱色株(命名为T-1-T-9),通过形态观察、生理特征及基于16S rRNA基因序列的分子生物学鉴定,初步认定分离株分属于芽孢杆菌属(Bacillus)、微小杆菌属(Exiguobacterium)、寡单胞菌属(Stenotrophomonas)和副球菌属(Paracoccus)。【结果】所得分离株纯培养均可不同程度地脱色单一偶氮染料和混合偶氮染料,其中T-8对甲基橙和金橙I的脱色速率最大,40 h的脱色率分别为85.9%和86.2%,T-8菌株干粉也可在无外源碳源的条件下完全脱色金橙I。分离株混合培养脱色混合偶氮染料的效率明显高于纯培养,可达90.1%。【结论】脱水污泥作为脱色偶氮染料功能菌群的新来源具有良好的应用价值。     

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.