黄绿木霉原生质体诱变育种研究*

利用正交实验方法研究了影响黄绿木霉(Trichoderma aureoviride)原生质体形成的因素,并利用紫外线、硫酸二乙酯、氯化锂几种因素复合诱变原生质体筛选高产纤维素酶菌株。影响原生质体形成的因子顺序是酶系统>菌龄>酶解时间>酶解温度,原生质体形成的最佳条件是0.5%蜗牛酶+0.5%溶菌酶+1.0%纤维素酶,菌龄为18h,酶解时间为3.0h,酶解温度为32℃;在该条件下原生质体产量可达到4.25×10⁶个mL^-1。Ca^{2+相似文献}   

木质层孔菌原生质体的制备与再生条件的研究

目的：提高木质层孔菌原生质体的产量和再生率,为进一步诱变育种提高菌株产木质纤维素酶活力打下基础。方法：通过单因素实验分别筛选合适的酶浓度、菌丝的菌龄、酶解温度、酶解时间、渗透压稳定剂与pH值。结果：在酶解液浓度为2.0%纤维素酶＋2.0%蜗牛酶、菌龄60h、酶解温度32℃、酶解时间3h,以0.8mol/L的NaCl溶液为渗透压稳定剂,pH值为5.0时,原生质体形成量达4.13×10^5个/mL,再生率可达6.95%。有效地提高了木质层孔菌原生质体的产量和再生率。     

轮梗霉原生质体的制备*

本文比较了酶浓度、菌龄、渗透压稳定剂以及酶解温度和时间等因素对轮梗霉原生质体得率的影响。结果基本获得了制备原生质体的适宜条件:用0.6mol/L甘露醇稳渗剂配制成的4%纤维素酶和0.5%蜗牛酶混合酶,35℃酶解培养了30h的菌丝1.0h,即可得到较高产量的原生质体。对该原生质体进行了再生实验,其再生率约为23.8%。     

白腐真菌原生质体制备和再生条件的研究

对影响白腐真菌(5．776)原生质体制备和再生的条件：包括菌龄、水解酶液的种类及浓度、酶解温度、酶解时间、再生培养基的稳渗剂的选择进行了研究。通过单因素比较分析和正交实验得到最适合的白腐真菌原生质体制备和再生条件。结果表明：当菌龄为58h,采用1%纤维素酶和1%蜗牛酶(2：1)混合液,酶解温度30℃,酶解时间180min,用0．7mol/L氯化钠作渗透压稳压剂,白腐真菌(5．776)原生质体的形成数和再生率均比优化前大为提高,原生质体形成量为8．36×10~5个/mL,原生质体再生率为9．12%。     

原生质体激光诱变选育少根根霉脂肪酶高产菌株

对少根根霉BUCT-11原生质体制备、再生条件及激光诱变育种进行了研究.结果显示,少根根霉BUCT-11原生质体形成及再生最佳条件为:菌龄24 h,混合酶由27 mg/mL的蜗牛酶和53 mg/mL的纤维素酶组成,酶解时间1.5 h,酶解温度30 ℃,渗透压稳定剂为0.6 mol/L NH4Cl、0.02 mol/L ...     

氦氖激光、紫外复合诱变天麻素产生菌华根霉LN-A的原生质体

本文通过研究酶组合、酶浓度、酶作用时间和菌龄等因素对天麻素产生菌华根霉(Rhizopus chinensis) LN-A原生质体制备和再生的影响, 总结出了原生质体制备和再生的最佳条件: 选用对数生长期的菌株, 以蜗牛酶5 mg/mL + 纤维素酶5 mg/mL + 溶菌酶2 mg/mL 30°C保温处理2 h, 原生质体形成率达5.8×107, 原生质体再生率为5.7%。在此基础上首次利用He-Ne激光、紫外线复合诱变天麻素合成菌的原生质体, 当选用15 mW的He-Ne激光辐射原生质体20 min, 再用紫外辐照150 s时获得了转化率及天麻素得率都明显提高的突变株, 其天麻素得率比出发菌株提高20%以上。     

冬虫夏草原生质体形成和再生的初步研究

研究冬虫夏草菌丝体的菌龄、酶种类、酶解温度、酶解时间、pH、稳渗剂和几种再生培养基对原生质体形成和再生的影响。最佳条件为 :生长 6d的菌丝体 ,组合酶 (1%蜗牛酶 +1%纤维素酶 ) ,酶解温度 36℃ ,酶解时间 2 .5h,pH6 .4 ,稳渗剂 0 .4M甘露醇溶液 ,RM3再生培养基。在此条件下原生质体的形成为 2 .0 4× 10 9个 ml,再生率为 0 .0 91%。     

茯苓原生质体制备与再生条件的研究

研究了酶、酶解时间、菌龄、稳渗剂等对茯苓原生质体制备与再生的影响。茯苓原生质体制备的最佳条件为:纤维素酶(1．5%)和蜗牛酶(1．5%)的等量混合酶解系统,酶解时间3h,7d菌龄菌丝,产量可达1．77×10~7个/mL。以甘露醇为稳渗剂,采用CYM再生培养基,酶解时间3h,7d菌龄菌丝,其原生质体再生率最高,为0．164%。这一结果为茯苓通过原生质体技术进行菌种改良提供了重要技术参数。     

蛹虫草原生质体紫外诱变选育胞外多糖高产菌株

蛹虫草是重要的药食兼用两用真菌,具有较高的医用及经济价值。本文通过单因素和正交试验的方法研究了不同酶系统、酶解温度、酶解时间、渗透压稳定剂、菌龄对蛹虫草原生质体形成的影响,并对蛹虫草原生质体进行紫外诱变,以生物量和胞外多糖产量为指标选育胞外多糖高产菌株。结果表明：在30℃、1％溶壁酶＋0．5％蜗牛酶＋0．5％纤维素酶条件下,以甘露醇为渗透压稳定剂对4日龄蛹虫草菌丝酶解2h,原生质体产量可达到9．2×10^6个/mL。从150株诱变株中筛选出1株最佳正诱变株,编号为44#,经深层培养其生物量比出发菌株提高10％,胞外多糖产量提高84．3％,继代培养10代后,遗传稳定性良好。     

小花棘豆Embellisia内生真菌原生质体的制备与再生研究

旨在获得数目多且活力高的小花棘豆Embellisia内生真菌的原生质体,分析和探讨该内生真菌原生质体制备与再生的最佳条件,为后续外源基因转化奠定基础。利用酶解法对制备小花棘豆Embellisia内生真菌菌丝的原生质体,研究酶解液成分、p H、温度、渗透压稳定剂、酶解时间及菌龄对原生质体制备和再生的影响;原生质体在TB3培养基上再生后,研究酶解时间对原生质体再生的影响。结果显示,2.5%(W/V)lysing enzymes、2%(W/V)纤维素酶和3%(W/V)蜗牛酶3种混合酶处理,菌龄为10 d,当酶解温度为30℃、p H5.8、1.2 mol/L Mg SO4为渗透压稳定剂,在80 r/min水平摇床酶解8 h时,原生质体浓度较高,达4.42×105个/m L;酶解时间6 h时再生率最高,达46.7%。     

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.