菊芋块茎浸提液对生菜种子萌发生长的化感作用

以新鲜菊芋块茎、烘干菊芋块茎全粉和菊粉的水浸液作为化感物质,以发芽率、芽长、根长、超氧化物歧化酶(SOD)、丙二醛(MDA)、可溶性蛋白作为种子萌发和幼苗生长的指标,探讨不同菊芋块茎浸提液对生菜种子萌发生长的化感作用。结果表明:当菊粉溶液浓度为40 mg·mL^-1(T4)时,发芽率最高,比对照高20.1%;当干样浸提液浓度为5 mg·mL^-1(T1)时,发芽率比对照高9.6%;当干样浸提液浓度为40 mg·mL^-1(T4)时,对生菜种苗芽长促进作用最明显,比对照高9.2%,在干样浸提液浓度为5 mg·mL^-1(T1)时,根长最长,比对照高28.3%;当菊芋块茎鲜样浸提液浓度为20 mg·mL^-1(T3)时,SOD的活性达到最高,而MDA含量低于对照,说明菊芋鲜样浸提液可以有效提高生菜的抗逆性;当菊粉溶液浓度为5 mg·mL^-1(T1)和10 mg·mL^-1(T2)时,MDA含量和蛋白含量极低,显著低于对照。采用化感综合效应指数分析菊芋...     

菊苣提取物和菊粉降脂活性研究

以300日龄商品代尼克T粉壳蛋鸡为试验动物,研究了菊苣提取物和菊粉对血清脂质、蛋黄总脂和胆固醇的影响.结果显示,0.1%菊苣提取物组、2.0%菊苣提取物组和0.1%菊粉组血清胆固醇(TC)、甘油三脂(TG)、低密度脂蛋白(LDL-C)均显著低于对照组(P<0.05),其中0.1%菊苣提取物组TC降低36.47%,TG降低40.71%,LDL-C降低36.09%,0.1%菊粉组LDL-C降低16.23%,差异极显著(P<0.01);2.0%菊苣提取物组高密度脂蛋白(HDL-C)比对照组高23.19%,差异极显著(P<0.01);2.0%菊苣提取物组蛋黄总脂和蛋黄胆固醇显著降低(P<0.05).表明菊苣提取物和菊粉均具有降血脂活性,但菊苣提取物比菊粉活性更强;菊苣提取物还具有降低蛋黄总脂和胆固醇的作用.     

马克斯克鲁维酵母菌菊粉酶的异源表达及低聚果糖制备工艺优化

【目的】低聚果糖是新型的食品和保健品原料,具有广阔的市场需求。以菊粉酶水解菊粉制备低聚果糖的酶法工艺是先进的绿色制造。本研究旨在获得高产的菊粉酶菌株及以菊粉为原料酶法制备低聚果糖的优化工艺。【方法】采用基因工程手段克隆马克斯克鲁维酵母菌(Kluyveromyces marxianus)的菊粉酶基因,实现其在毕赤酵母中的高效表达;测定菊粉酶在不同p H、温度、金属离子和底物浓度等条件下的酶活变化趋势,获得最佳的反应参数;通过高效液相色谱法检测水解产物,获得不同酶量水解产物各组分分布。【结果】菊粉酶工程菌株在10 L发酵罐中的产菊粉酶活达1 570 U/m L、蛋白质含量为2.75 g/L发酵液;菊粉酶最适反应参数为:在体积为1 L的反应体系中,p H 5.0、反应温度50°C、含0.2 mmol/L Mg2+以及菊粉浓度为8%。在该条件下,酶量为10 U时菊粉被完全水解。水解产物中单糖和二糖含量仅为9.25%,而低聚果糖(C3-C8)含量为90.75%,且C3-C5低聚果糖含量高达72.92%。【结论】克隆了K.marxianus菊粉酶基因并实现了高效表达,获得了水解菊粉制备低聚果糖的最佳工艺条件。为菊粉酶的大量生产及低聚果糖的酶法制备奠定了良好的基础。     

酶水解菊芋糖浆发酵生产琥珀酸的初步研究

用产菊粉酶的一株黑曲霉菌株进行产酶发酵条件和水解条件研究,在30℃,pH 6.0,摇床转速200 r/min,发酵时间为3 d的最适产酶条件下,酶活可以达到45.9 U/mL.以总糖含量为85.2 g/L的菊芋粉为初始底物,最适酶水解条件为温度50℃,加黑曲霉培养液的量为10%(v/v),水解12 h后,水解率达到99.6%.用此酶解液在5 L搅拌发酵罐中进行琥珀酸发酵,初始还原糖浓度53.5 g/L,36 h发酵产琥珀酸43.8 g/L,琥珀酸产率0.83 g/g,糖利用率99.0%,琥珀酸生产强度1.22 g/(L·h).     

稀酸水解玉米芯制备丁二酸

利用正交设计得到稀H2SO4水解玉米芯制备混合糖液的优化工艺:玉米芯料液比1∶5(质量体积比),物料粒径250~380μm、H2SO4用量3%(体积分数)、水解温度126℃、反应时间2.5 h。此工艺条件下的总糖收率达90%,总糖质量浓度为60 g/L,发酵抑制物糠醛含量为0.87 g/L,5-羟甲基糠醛含量为0.68 g/L。在此基础上利用活性炭吸附和Ca(OH)2中和对玉米芯混合糖液进行脱毒及脱盐处理,SO42-脱除率达96%,色素脱除率为96%,糠醛、5-羟甲基糠醛及多酚类物质脱除率均高于50%。处理后的玉米芯多组分糖液作为产琥珀酸放线杆菌(Actinobacillus succino-genes)NJ113的发酵C源,当培养基中初始总糖质量浓度为50 g/L时,丁二酸收率为61.68%,丁二酸质量浓度为30.8 g/L;初始总糖质量浓度为70 g/L时,丁二酸收率仍可达50%以上,丁二酸质量浓度为35.2 g/L。发酵实验表明,将经过脱毒脱盐处理的玉米芯多组分糖液替代葡萄糖作为C源发酵制备丁二酸具有可行性。     

内切酶法制取菊苣低聚果糖工艺条件的研究

目的:利用毕赤嗜甲醇酵母表达的重组黑曲霉菊粉内切酶,从菊苣菊粉中制取低聚果糖。方法:用重组黑曲霉菊粉内切酶酶解水提菊粉,用薄层色谱、离子色谱分析酶解产物,研究酶解条件,分析产物组成。结果与结论:菊粉浓度为20～160g/L、酶浓度为12U/g菊粉时,低聚果糖的最大产率逐渐升高然后下降;在接近最大溶解度200g/L时,菊粉寡糖最大产率为62.0%,最大产率与酶的用量无关,但提高酶的浓度可以缩短达到最大产率的时间。pH5.5、50℃、菊粉浓度为40g/L、酶用量为12U/g菊粉时,可达到最大产率64.6%;酶解的产物主要为GF2到GF10的菊粉寡糖。     

无载体固定化酵母细胞木薯淀粉质原料酒精连续发酵研究

以木薯粉糖化液为发酵底物,在总发酵体积(有效)为15L的悬浮床生物反应器中,对一株粟酒裂殖酵母变异株进行一级和二级连续发酵研究。结果表明,二级连续发酵系统可明显改善一级系统的不足,并取得了平均流加糖液浓度150g/L,发酵强度为97g/L.h,流出液酒精浓度727g/L,残糖浓度374g./L,总糖利用率达90%的较好结果;整个系统在连续一个月的运行中从未发现染菌现象,发酵操作稳定。     

双孢蘑菇水提物抗氧化活性研究

采用秀丽线虫为模型及DPPH清除试验对双孢蘑菇新鲜和干子实体的水提物进行抗氧化活性比较。试验结果显示,双孢蘑菇干菇水提物抗氧化活性最强,其次是鲜菇水提物,鲜菇常温浸提物抗氧化活性最低。干菇水提物浓度为0.5 mg/m L时,秀丽线虫的最大寿命为7 d,平均寿命为3.84 d,均显著高于对照组。鲜菇浸提物对DPPH自由基清除能力最高,达69.19%,其次是干菇水提物和鲜菇水提物,清除率分别为54.66%和51.82%。双孢蘑菇水提物中多酚的含量与清除DPPH自由基的能力存在良好相关性,鲜菇浸提物含总多酚最高,为3.98%。本研究的研究结果为明确双孢蘑菇开发利用方向提供有用的参考价值。     

菊芋粕菊粉的酶法提取、组成及抗氧化活性研究

本研究拟应用酶法提取技术解决菊芋菊粉工业化生产中的废弃物——菊芋粕再利用程度低的问题,并评价菊芋粕菊粉的抗氧化活性功效。对菊芋粕菊粉的果胶酶酶法提取的最佳条件通过响应面法进行了优化,并对菊芋初次水提菊粉(primary water-extracted inulin,PWI)和二次酶提菊粉(secondary enzymatic-extracted inulin,SEI)的组成成分和抗氧化活性进行了比较分析。响应面法优化确定的菊芋粕菊粉最佳酶法提取条件为:pH4.5、提取温度50 ℃、酶底比7.5 U/g、提取时间2 h,该提取方法所得菊芋粕菊粉的得率为35.30%±0.85%,与传统热水浸提法相比菊粉得率提高38.16%。组成分析结果显示,SEI的总糖和菊粉含量均显著高于PWI( P <0.05)。在菊粉聚合度方面,PWI中蔗果三糖和蔗果四糖含量较高,而SEI中蔗果五糖、蔗果六糖及其以上聚合度菊粉的含量较高。此外,SEI的抗氧化活性优于PWI。因此,果胶酶辅助提取方法有望为菊芋粕菊粉的再利用难题提供新的解决思路。     

新疆菊苣籽中总黄酮提取工艺研究

目的:以芦丁为标准品,采用分光光度法测定菊苣籽中总黄酮含量 .方法:在提取过程中通 过单因素实验,分析了乙醇浓度、回流温度、提取时间及料液比等四个因素对提取 率的影响.在单因素实验的基础上建立正交实验,优化菊苣籽总黄酮提取工艺条件.结果: 在最佳吸收波长512nm处,菊苣籽最佳提取工艺条件为乙醇浓度70%,料液比1∶50, 回流温 度70℃,提取时间2h,最佳黄酮含量C为3.80%.结论:以芦丁为对照品 ,用紫外可见分光光度法测定菊苣籽中总黄酮含量,方法简单,准确度较高.     

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.