酶法脱蛋白提取大枣多糖工艺的研究

讨论了从提取环磷酸腺苷后的枣汁中提取枣多糖的最佳工艺条件,包括枣汁浓缩4倍,加无水乙醇调枣汁中乙醇体积分数为60%,醇沉5 h;木瓜蛋白酶脱蛋白效果最佳,木瓜蛋白酶液与枣汁的体积比为0.4∶ 1,温度60℃、pH5.0,酶解90 min,蛋白脱除率可达91.8%;AB-8树脂脱色,脱色率为73.64%,多糖得率为94.4%.红外光谱显示,提取的多糖与常规方法提取的多糖成分相同.     

小白及多糖提取、脱蛋白工艺及抗氧化性研究

本研究探讨了小白及多糖提取、脱蛋白工艺及其抗氧化性。以粗多糖提取率为指标,在单因素实验的基础上进行正交试验,探讨微波额定功率百分比、微波时间、浸提温度、浸提时间对粗多糖提取率的影响,得到最佳提取工艺参数:微波功率为额定功率的40%,微波时间60 s,浸提温度70℃,浸提时间2.5 h,在此条件下小白及多糖的得率为38.33%。脱蛋白实验结果显示:酶-Sevag法脱蛋白效果最好,其蛋白质脱除率为80.01%,多糖损失率为24.58%。比较小白及多糖的抗氧化性,得出酶制小白及多糖和小白及粗多糖对DPPH自由基、O■有较好的清除能力,其IC_(50)值分别为24.855、28.948μg/mL,0.212、0.223 mg/mL。研究结果为小白及等药用植物多糖的提取及综合利用提供借鉴。     

地木耳多糖的提取与纯化研究

对地木耳采用水提醇沉法获得的地木耳多糖粗提取物,采用Sevage法脱蛋白质、醇沉,干燥得粗多糖,进一步用DEAE-52纤维素柱层析分离纯化,用纸色谱和琼脂糖凝胶电泳对洗脱组分进行纯度鉴定。结果表明：Sevage法脱蛋白7次可脱除94%的蛋白质,多糖得率为13.75%。DEAE-52纤维素柱层析后得到10种组分,浓缩干燥后得到白色粉末状多糖组分,每个组分经过纯度鉴定后均为单一的多糖。选择水和NaC l溶液为洗脱剂的温和条件分离纯化多糖效果较好。     

金针菇深层发酵菌丝体中水溶性多糖的提取条件的研究

本文研究了食用菌深层发酵金针菇菌丝体多糖的提取条件。实验表明,在加水比为１：６,沸水提取４小时,进行三次抽提后,用４倍乙醇沉淀所获粗多糖得率最高。粗多糖经脱色去蛋白后以７０％（Ｖ／Ｖ）乙醇分级可获得最高级分精制多糖。     

不同提取方法对豫产白花蛇舌草多糖及抗氧化活性的影响

为评价不同提取方法对河南地区白花蛇舌草粗多糖的得率、总碳水化合物含量、杂质含量和抗氧化活性的影响,本实验分别以传统热水提取法、超声波辅助提取法、纤维素酶提取法从该药材中提取多糖。同时测定了粗多糖中总碳水化合物含量、杂质含量(总蛋白和总酚含量)以及羟基自由基清除能力、DPPH自由基清能力、还原力等抗氧化能力。实验结果显示三种提取法所得粗多糖相对于原药材的得率分别为6.77±0.09%、6.37±0.01%和4.81±0.90%;粗多糖中的总碳水化合物含量分别为289.14±1.33、246.83±2.33和278.92±2.92mg/g。粗多糖中总蛋白含量分别为28.59±2.21、23.26±2.43和4.96±0.18mg/g,总酚类成分含量分别为5.9±0.08、5.31±0.40和2.82±0.07mg/g。抗氧化活性实验结果表明,三种粗多糖的羟基自由基清除能力呈现出浓度依赖性,且均在3.0mg/mL时达到最大,对应最大清除率分别为89.13%、85.87%和74.71%。另外,三种粗多糖的DPPH自由基清除率分别在0.75~3.0mg/mL的浓度区间内达到最大并保持稳定,对应清除率的稳定区间分别为77.02%~77.90%、77.06%~77.96%和83.16%~85.73%。综上所述,以上三种不同提取方法对白花蛇舌草多糖的品质影响较大,可以为豫产白花蛇舌草的品质鉴别、多糖质量控制和开发利用提供依据。     

百尾参多糖脱色脱蛋白工艺及其免疫活性研究

以百尾参多糖脱色率、多糖损失率为指标,通过单因素和正交试验研究活性炭含量、时间、温度和pH对多糖脱色效果的影响,优化百尾参多糖最佳脱色条件;对Sevage法、三氯乙酸（TCA）法、蛋白质等电点法以及酶法4种脱蛋白方法进行比较,选择较好的脱蛋白方法。建立环磷酰胺免疫低下小鼠模型,研究百尾参多糖的免疫调节活性。结果表明活性炭脱色的最佳条件是活性炭加入量1%、温度60 ℃,时间45 min、pH 4.5;酶法为4种方法中较好的脱蛋白方法。百尾参多糖能加速恢复环磷酰胺致小鼠免疫器官萎缩,也能剂量依赖性地提高小鼠血清中的白介素-2（IL-2）、肿瘤坏死因子α（TNF-α）等细胞因子含量,表明百尾参多糖对环磷酰胺的免疫抑制具有保护作用。     

仙人掌多糖提取过程中脱蛋白方法的研究

用水提取的仙人掌多糖常含有蛋白质C,实验以多糖损失率和脱蛋白率为衡量指标,选用了Sevag法、三氯乙酸法和酶法对仙人掌多糖提取物进行脱蛋白处理。实验结果表明,酶法、三氯乙酸法和Sevag法的脱蛋白率分别为89.67%、56.20%和45.65%,多糖损失率分别为7.19%、9.49%和13.75%。因此,酶提取法是替代常规方法的一种有效方法。     

三角帆蚌多糖的微波辅助提取及脱蛋白工艺

运用微波辅助处理、热水浸提、乙醇沉淀、Sevag法脱蛋白的方法提取制备三角帆蚌多糖。在单因素实验基础上,运用正交实验对三角帆蚌多糖微波辅助提取及Sevag法脱蛋白的工艺参数进行优化。结果显示:三角帆蚌多糖微波辅助提取的最优条件为:水料比15 mL/g、提取温度50℃、微波处理时间150 s、微波功率1080 W。在此条件下,多糖的提取得率为4.06%。三角帆蚌多糖Sevag法脱蛋白的最优参数组合为:正丁醇与氯仿体积比0.20、正丁醇-氯仿混合液用量占多糖溶液的体积百分比20%、脱蛋白振摇时间10 min、脱蛋白次数8次。在此条件下,多糖的蛋白去除率、多糖保留率分别是52.24%和65.13%。     

野生树舌多糖的脱色和脱蛋白

从野生树舌中提取水溶性多糖,经乙醇沉淀后得多糖,并分别用活性碳,苯酚,DEAE纤维素,H2O2等4种方法进行脱色,并以酵母聚糖为标准品比较脱色效果,用紫外和可见光谱扫描法检测有色杂质的去除效果;用Zn盐,胰蛋白酶,有机溶剂,胰蛋白酶加有机溶剂等4种方法脱蛋白,以比较不同方法脱色,脱蛋白的效果。结果表明用质量分数为0.75%的活性碳脱色后,有色杂质的去除效果最好,光谱吸收峰最接近标准品;单独使用有机溶剂的脱蛋白效果最好。     

四种真菌油脂提取方法的比较研究

采用索氏法、超临界CO2萃取法、酸热法和有机溶剂法分别提取雅致枝霉、拉曼被孢霉、少根根霉、畸雌腐霉和橙黄红酵母的油脂,从样品要求、最小样品量、仪器要求、处理样品能力及油脂得率等方面对4种提取方法进行综合评价,并对索氏法、超临界CO2萃取法和酸热法提取的雅致枝霉油脂的脂肪酸组成进行气相色谱分析。索氏法的油脂得率最高,但耗时较长;超临界CO2萃取法和酸热法的油脂得率相近,较索氏法略低,但酸热法更为简便,单位时间内样品处理能力强;有机溶剂法提取效果最差。我们建立的酸热法是一种适合油脂及多水饱和脂肪酸高产菌株筛选的简便、有效的真菌油脂提取方法。     

壳聚糖酶的克隆表达与壳寡糖的制备分析

目的:克隆壳聚糖酶基因于大肠杆菌中实现高表达,制备壳寡糖。方法:以枯草芽孢杆菌总DNA为模板扩增壳聚糖酶基因(CSN),克隆至载体pET23a(+)上,转化菌株BL21(DE3)。重组子经0.5 mmol/L IPTG诱导后,SDS-PAGE和质谱检测与鉴定重组酶。酶纯化后水解壳聚糖,薄层色谱分析其水解产物。结果:质谱证明壳聚糖酶(31.5kDa)成功表达,表达量占菌体总蛋白的45%左右。纯化后重组酶浓度为900 mg/L,纯度95%、回收率85%,酶活力为10 000 U/mg。壳聚糖降解产物为壳二糖至壳四糖。结论:原核表达载体pET23a(+)-CSN构建正确,壳聚糖酶表达量与活性高,适用于水解壳聚糖制备壳寡糖。     

国内外蝗害治理技术现状与展望

本文首先概述了国内外蝗虫发生与为害的态势,总结了现阶段我国蝗虫发生与为害的主要特点:即农田飞蝗暴发频繁而且严重,草原土蝗的发生时常造成严重的经济损失,而且侵入城市干扰市民生活,我国与周边国家之间蝗虫过境迁移频繁,使用化学农药污染环境和农产品;分析了国内外蝗虫防治对策与技术的发展现状,重点介绍了应急防治和可持续治理对策、...     

Synthesis and turnover of cerebrosides and phosphatidylserine of myelin and microsomal fractions of adult and developing rat brain.

The synthesis and turnover of cerebrosides and phospholipids was followed in microsomal and myelin fractions of developing and adult rat brains after an intracerebral injection of [U-14C]serine. The kinetics of incorporation of radioactivity into microsomal and myelin cerebrosides indicate the possibility of a precursor-product relationship between cerebrosides of these membranes. The specific radioactivity of myelin cerebrosides was corrected for the deposition of newly formed cerebrosides in myelin. Multiphasic curves were obtained for the decline in specific radioactivity of myelin and microsomal cerebrosides, suggesting different cerebroside pools in these membranes. The half-life of the fast turning-over pool of cerebrosides of myelin was 7 and 22 days for the developing and adult rat brain respectively. The half-life of the slowly turning-over pool of myelin cerebrosides was about 145 days for both groups of animals. The half-life of the rapidly turning-over microsomal cerebrosides was calculated to be 20 and 40 h for the developing and adult animals respectively. The half-life of the intermediate and slowly turning-over microsomal cerebrosides was 11 and 60 days respectively, for both groups of animals. The amount of incorporation of radioactivity into microsomal cerebrosides from L-serine was greatly decreased in the adult animals, and greater amounts of the precursor were directed towards the synthesis of phosphatidylserine. In the developing animals, considerable amounts of cerebrosides were synthesized from L-serine, besides phosphatidylserine. The time-course of incorporation indicated that a precursor-product relationship exists between microsomal and myelin phosphatidylserine. The half-life of microsomal phosphatidylserine was calculated to be about 8 h for the fast turning-over pool in both groups of animals.     

Identification and composition of the tonsillar and anal enterococcal and streptococcal flora of dogs and cats

Enterococcus faecalis was the most frequently isolated enterococcal species from anal swabs and tonsils of dogs and cats, although in the anal samples from dogs Ent. hirae was found almost as often as Ent. faecalis. Most Ent.faecium strains from dog tonsils differed from those associated with humans and other animals in that they fermented sorbitol. Typical Ent. avium as well as atypical Ent. avium -like strains were seen in dogs, while the related species Ent. raffinosus was associated with cat tonsils. Enterococcus cecorum also occurred mainly in cats. Certain atypical strains, presumptively identified as Ent. cecorum , shared characteristics with Ent. columbae.
The most frequent streptococcal species in tonsils of cats and dogs were Streptococcus suis and Strep. canis. Streptococcus canis and Strep. bovis predominated in anal swabs. The canine Strep. suis differed from the common porcine strains in fermenting mannitol.
Forty-seven of the 288 isolates examined could not be identified or related to known species. The characteristics of two groups of these bacteria, provisionally called 'Ton 31 group' and 'O7 group' are described.     

Molecular characterisation of species and genotypes of Cryptosporidium and Giardia and assessment of zoonotic transmission

The molecular characterisation of species and genotypes of Cryptosporidium and Giardia is essential for accurately identifying organisms and assessing zoonotic transmission. Results of recent molecular epidemiological studies strongly suggest that zoonotic transmission plays an important role in cryptosporidiosis epidemiology. In such cases the most prevalent zoonotic species is Cryptosporidium parvum. Genotyping and subtyping data suggest that zoonotic transmission is not as prevalent in the epidemiology of giardiasis. Molecular characterisation of Cryptosporidium and Giardia is a relatively recent application that is evolving as new genes are found that increase the accuracy of identification while discovering a greater diversity of species and yet unnamed taxa within these two important genera. As molecular data accumulate, our understanding of the role of zoonotic transmission in epidemiology and clinical manifestations is becoming clearer.     

白术同源四倍体的诱导和鉴定及其与二倍体过氧化物酶的比较

以白术（Atractylodes macrooephala Koidz.）二倍体组培苗为材料,对其四倍体诱导方法进行研究,共获得45个白术同源四倍体株系,为优良株系的选育提供了材料。此外,还分析比较了其中8个白术四倍体株系与二倍体的过氧化物酶同工酶（POD）的酶谱差异,发现四倍体各株系过氧化物酶同工酶谱比二倍体的均多了Rf0.310的谱带,且总过氧化物酶比活力也发生了很大改变,对探讨白术四倍体优良株系的生理生化机理具有一定的参考价值。     

Kinetics and thermodynamics of peroxidase- and laccase-catalyzed oxidation of N-substituted phenothiazines and phenoxazines

N -substituted phenothiazines (PTs) and phenoxazines (POs) catalyzed by fungal Coprinus cinereus peroxidase and Polyporus pinsitus laccase were investigated at pH 4–10. In the case of peroxidase, an apparent bimolecular rate constant (expressed as k _cat/K _m) varied from 1 ×10⁷M⁻¹s⁻¹to 2.6×10⁸M⁻¹s⁻¹ at pH 7.0. The constants for PO oxidation were higher in comparison to PT. pH dependence revealed two or three ionizable groups with pK _a values of 4.9–5.7 and 7.7–9.7 that significantly affected the activity of peroxidase. Single-turnover experiments showed that the limiting step of PT oxidation was reduction of compound II and second-order rate constants were obtained which were consistent with the constants at steady-state conditions. Laccase-catalyzed PT and PO oxidation rates were lower; apparent bimolecular rate constants varied from 1.8×10⁵M⁻¹s⁻¹ to 2.0×10⁷M⁻¹s⁻¹ at pH 5.3. PO constants were higher in comparison to PT, as was the case with peroxidase. The dependence of the apparent bimolecular constants of compound II or copper type 1 reduction, in the case of peroxidase or laccase, respectively, was analyzed in the framework of the Marcus outer-sphere electron-transfer theory. Peroxidase-catalyzed reactions with PT, as well as PO, fitted the same hyperbolic dependence with a maximal oxidation rate of 1.6×10⁸M⁻¹s⁻¹ and a reorganization energy of 0.30 eV. The respective parameters for laccase were 5.0×10⁷M⁻¹s⁻¹ and 0.29 eV. Received: 20 September 1999 / Accepted: 24 February 2000