Production of Salidroside Through Biotransformation of Exogenous Tyrosol in Rhodiola sachalinensis Cell Suspension Cultures

In Rhodiola sachalinensis A. Bot. cell cultures, low yields of salidroside was supposed to be associated with the low efficiency of glucosylation reaction at the stationary phase of cell growth, when large amounts of the substrate, aglycon tyrosol, were accumulated. Considering the activity of tyrosol glucosyhransferase being the highest at the exponential growth phase, the author added exogenous tyrosol into the cultures at this time so as to produce salidroside through biotransformation. The effects of tyrosol concentration, the way of tyrosol addition as well as the cell density on the transformation rate and salidroside yield were investigated. It was found that the transformation rate attained 95 % after cells were incubated in the medium containing 1 mmol/L tyrosol for 24 h. Excess high concentrations of tyrosol in medium ( > 3 mmol/L) caused inhibition of transformation rate and cell growth. By 3 repeated additions of tyrosol in low concentrations, the salidroside yields of 1 320 mg/L, 1 740 mg/L and 1 980 mg/L to the cell densities of 6 g DW/L, 12 g DW/L and 18 g DW/L were obtained respectively.     

高山红景天年龄与根部红景天甙含量的关系

对1998年8月和1999年7月采自吉林省长白山自然保护区内共14个天然居群和人工栽培于黑龙江省大兴安岭的高山红景天的年龄和根部红景天甙含量的关系进行了研究。高山红景天的年龄根据其根茎上芽磷痕的数量判断。结果表明,人工栽培的高山红景天的年龄与其根部红景天甙的含量呈显著正相关,而长白山自然保护区内自然生境下的高山红景天,其根部的红景天甙含量与年龄的正相关性则较弱。     

超临界CO2萃取红景天中红景天苷、苷元酪醇的研究

采用超临界CO₂ 萃取法和乙醇常温浸提法相比较, 研究从红景天中提取红景天苷、苷元酪醇的工艺条件, 结论是:采用超临界CO₂ 萃取法能萃取出红景天生药中红景天苷的1.2%, 提取率不高, 但该方法能萃取出80%的苷元酪醇, 萃取液中苷元酪醇的相对含量可达45.68%;乙醇常温浸提法能将红景天苷、苷元酪醇同时有效萃取, 且得率较高, 但是萃取液中两物质相对含量较低, 进一步分离纯化将有难度。本研究结果表明, 将超临界CO₂ 萃取法和乙醇常温浸提法有效结合, 可实现两物质的有效分离, 推进红景天有效成分的产业化进程。     

HPLC法测定红景天居群中红景天苷的分布式样

本文以HPLC法作为测定红景天苷的方法,调查红景天苷在红景天不同种、不同居群中的分布式样。实验中采集不同种、同种不同居群、同居群不同个体的红景天样品,进行红景天苷的含量测定。结果表明红景天苷在不同红景天中分布差异较大,同种不同居群间多型性、居群内及个体间多态性显著。HPLC比法简便、快速、准确、重复性好,适用于研究红景天苷在药用红景天居群中的分布。     

镉胁迫下3种藓类植物抗氧化酶活性变化的比较研究

采用水培实验研究了重金属Cd对3种藓类植物尖叶拟船叶藓(Dolichomitriopsis diversiformis)、湿地匍灯藓(Plagiomnium acutum)和匍枝青藓(Brachythecium procumbens)的抗氧化酶系统(SOD、POD和CAT)的影响.结果表明,在1-100 mg·L-1的镉胁迫浓度范围内,Cd对3种藓类植物的SOD活性都具有显著的促进作用,SOD对Cd胁迫的种间敏感性顺序为尖叶拟船叶藓>湿地匍灯藓>匍枝青藓;3种藓类植物的POD和CAT活性对Cd胁迫均表现为先升后降,POD对Cd胁迫的种间敏感性顺序为匍枝青藓>湿地匍灯藓>尖叶拟船叶藓;高浓度Cd对CAT具有明显的抑制效应,CAT对Cd胁迫的种间敏感性顺序为湿地匍灯藓>尖叶拟船叶藓>匍枝青藓.在Cd长期胁迫下,SOD对3种藓类植物体内活性氧的清除起到关键作用,可作为藓类植物抗镉能力强弱的敏感生理指标;3种鲜类植物中匍枝青藓的抗镉能力最强,湿地匍灯藓次之,尖叶拟船叶藓最弱,并且这种抗性与cd在植物体内的积累成反相关.     

蝮蛇抗栓酶对家兔慢性胆囊炎防治的实验研究

作者用家兔４２只随机分成造型组（Ａ）,预防组（Ｂ）及治疗组（Ｃ）。各组又分处理组（Ａ１、Ｂ１、Ｃ１）和对照组（Ａ２、Ｂ２、Ｃ２）两个亚组。Ａ２组仅喂基本饲料,其余５组喂基本饲料加造型剂。Ａ组没用任何治疗。Ｂ１组慢性胆囊炎形成前,Ｃ１组慢性胆囊炎形成后分别用蝮蛇抗栓酶（０．２Ｕ／ｋｇ／日３０天）,Ｂ２和Ｃ２组仅给等量生理盐水。Ａ２及治疗后的Ｂ１、Ｃ１组血清胆固醇含量均明显低于Ａ１、Ｂ２、Ｃ２组（Ｐ＜０．０５）。胆囊的病理变化,Ｂ２和Ｃ２组改变明显,表面呈暗褐色,与周围组织粘连,粘膜面粗糙,胆囊壁增厚,体积增加,胆汁潴留,镜下粘膜增生呈乳头状,部分粘膜脱落,粘膜下及肌层水肿,炎细胞浸润。结果表明,蝮蛇抗栓酶对慢性胆囊炎既有预防作用又有治疗作用。     

双酶法制备玉米皮膳食纤维的研究

采用蛋白酶和淀粉酶结合水解制备玉米皮膳食纤维,通过正交试验确立了玉米皮膳食纤维的双酶法制备工艺。双酶法制备的玉米皮膳食纤维的产率为59.4%,膳食纤维的蛋白质量分数为0.82%,淀粉质量分数为1.42%,灰分为0.4%,水分质量分数为8.6%,持水力为5.9±0.4 g.g-1。     

多炔化合物氧化胁迫下稗草细胞保护酶系的反应

用多炔类化合物1-苯基-4-(3,4-亚甲二氧)-苯基丁二炔(简称化合物5)处理稗草(Echinochloa crusgalli)愈伤组织,经紫外光(320～400nm)照射后,诱导细胞内形成氧化胁迫环境。利用生化酶学方法,测定几种保护酶系在氧化环境下的活性变化。发现经化合物5和照光处理后,可诱导激活细胞内的谷胱甘肽-S-转移酶(GST)、谷胱甘肽过氧化物酶(GSH-Px)和过氧化物酶(POD)的活性,而超氧化歧化酶(SOD)则表现为活性受抑制。以0．1～10mg／L的浓度处理,所测GST、GSH-Px和POD的照光诱导活性明显高于未经照光处理的活性。其中以10mg／L,的浓度处理,照光所提高3种酶活性的百分率分别为10．47％、113．68％和166．68％。以1mg／L和10mg／L的浓度处理,照光对SOD的抑制百分率分别为50．25％和76．46％。测定结果表明：在外源光敏物质引起细胞内的氧化胁迫环境下,可激活细胞内保护酶的活性,用于抵御氧化逆境对细胞的损伤。而SOD则可能是化合物5光活化抑制稗草生长的生化作用靶标酶之一。     

Effects of Water on Enzyme Performance with an Emphasis on the Reactions in Supercritical Fluids

ABSTRACT

Enzymes require a certain level of water in their structures in order to maintain their natural conformation, allowing them to deliver their full functionality. Furthermore, as a modifier of the solvent, up to a certain level, water can modify the solvent properties such as polarity/polarizability as well as the solubility of the reactants and the products. In addition, depending on the type of the reaction, water can be a substrate (e.g., in hydrolysis) or a product (e.g., in esterolysis) of the enzymatic reaction, influencing the enzyme turnover in different ways. It is found that regardless of the type of reaction, the functionality of enzyme itself is maximum at an optimum level of water, beyond which the enzyme performance is declined due to the loss in enzyme stability. Furthermore, mass transfer limitations caused by pathway blockage and/or by reduced solubilities of the reactants and/or products can also affect the enzyme performance at higher water levels. Controlling water content of ingoing CO₂ and substrates as well as precise management of enzyme support and salt hydrates are important strategies to adjust water level in reaction media, especially in supercritical environments.