Chemical modification, characterization and bioactivity of Chinese lacquer polysaccharides from lac tree Rhus vernicifera against leukopenia induced by cyclophosphamide

Lacquer polysaccharide (LP) was isolated from the sap of lac tree (Rhus vernicifera). Its derivatives, carboxymethyl LP, sulfated LP and debranching LP were prepared. Their structure was analyzed by GPC, FT-IR and NMR spectroscopy. The sugar components of carboxymethyl and sulfated LPs hardly changed, but the molecular weight of the former decreased. The side chains of LPs were partially removed using sodium periodate in mild conditions and the pyranose ring β-configuration of products obtained was not changed. Bioactivity of natural and modified LPs against leukopenia induced by cyclophosphamide (CP) was investigated in mice. LP exhibited a significant bioactivity (P<0.05) compared to positive control group (CP). The bioactivity could increase slightly with the increasing of the contents of carboxymethyl groups. However, with the removal of the side chains and the incorporation of sulfate groups, the bioactivity gradually decreased. These showed that the bioactivity of lacquer polysaccharides against leukopenia induced by CP was strongly dependent on the types of ionic groups of the polysaccharides and concerned with the side chains with 4-O-methyl-β-glucuronic acid in the terminal.     

野油菜黄单胞菌野油菜致病变种中一个与EPS合成有关的新基因的鉴定

用转座子Tn5gusA5对野油菜黄单胞菌野油菜致病变种(Xanthomonas campestris pv.campestris,简称Xcc)野生型菌株8004进行诱变,分离到一批胞外多糖(EPS)合成减少的突变体。采用TAIL-PCR(thermal asymmetric interlaced PCR)分析突变体的Tn5gusA5插入位点,发现其中一株编号为151D09的突变体的插入位点位于Xcc 8004菌株的基因组编号为XC3695的ORF内,该ORF功能尚未见报道。序列分析表明,该ORF演绎的编码产物与Serratia marcescens的kdtX基因和Klebsiella pneumoniae的waaE基因演绎的编码产物分别具有52%和50%的相似性,并具有第2家族糖基转移酶的功能域, 因此暂将该ORF命名为waxE基因。用同源双交换方法构建了waxE基因的缺失突变体,并采用PCR和Southern杂交的方法对突变体进行了验证。waxE基因缺失突变体在营养丰富培养基的生长繁殖不受影响,但其EPS产量与野生型菌株8004相比,降低35%左右,并且一段PCR合成的包含waxE基因的DNA片段能反式互补waxE基因缺失突变体,恢复缺失突变体的EPS产量,表明Xcc waxE基因与EPS的生物合成有关。     

两种多糖对日本沼虾酚氧化酶活力的影响

在饲料中分别添加 1‰的云芝多糖和虫草多糖 ,对日本沼虾进行投喂 ,通过连续测定日本沼虾血清中的酚氧化酶活力 ,研究两种多糖对日本沼虾免疫机能的作用。结果表明 ,在平均水温为 2 3 8℃± 3 8℃时 ,云芝组、虫草组分别较对照组提高了 34 52 %、84 62 % ;在平均水温为 1 0 8± 2 4℃时 ,云芝组和虫草组分别较对照组提高了30 0 2 %、5 1 2 % ,因而云芝多糖和虫草多糖能明显地增强日本沼虾血清的酚氧化酶活力。另经实验表明 ,在王雷所确立的酚氧化酶活力的检测条件下 ,其PO活力为 8 3units/mL ,而在Horowitz所确立的检测条件下 ,其PO活力为2 90units/mL ,并且后者检测方法重复性好 ,能较好地反映日本沼虾的免疫状态。     

木立芦荟多糖提取的工艺优化及其清除活性氧自由基的研究

对影响木立芦荟多糖提取的温度、时间和乙醇浓度3个因素进行L9(33)正交试验,分析其主要影响因素并对提取多糖进行活性测定。结果表明:提取温度显著影响多糖得率,最佳工艺条件为提取温度85℃、乙醇体积分数80%,时间1 h。用过硫酸铵/N,N,N,,N,-四甲基乙二胺(AP/TEMED)体系产生的氧自由基O2-.对在最佳工艺条件下得到的多糖进行活性氧自由基清除研究,发现其具有较高的清除能力。     

The production-influencing factors of extracellular polysacchadde(EPS) from a Strain of lactic acid bacteria and EPS extraction

The influencing factors of extracellular polysaccharide(EPS)produced from a strain of lactic acid bacteria(LAB L15)were studied by using the phenol-H2SO4 method.It was demonstrated that the strain produced EPS at the most amount when it was incubated for 40-48 h and when the pH value was 4 under 30℃.Glucose was the most suitable carbon source for LAB-producing EPS.The rough EPS was obtained from L15 culture after centrifugation,dialysis,deprotein,decoloration,and ethanol-precipitation.The sample was at least composed of two polysaccharides mat were completely different in molecular weight and the amount.The purified EPS was passed through the SephadexG-200 colunm and it showed that it was a sample purified by thin layer chromatography.     

真菌多糖抗肿瘤及免疫调节作用研究进展

真菌多糖被认为是目前最有开发前途的保健食品和药品的新资源之一,对真菌多糖的生物活性研究也是保健食品功能因子中最为炽热的研究热点。本文综述了近年来国内外真菌多糖抗肿瘤及免疫调节作用的研究进展。     

锁阳多糖提取工艺的研究

以浸膏得率和浸膏中多糖质量分数综合评价,利用L9(34)正交实验从水提和醇沉两方面优选锁阳中水溶性多糖最佳提取工艺条件,为锁阳活性多糖的开发提供科学依据和实验基础。最佳水提工艺条件为:m(锁阳):v(水)=1:12,回流提取0.5 h,提取2次;最佳醇沉工艺条件为:在m(生药):v(水提液)=1 g:2 mL溶液中加入乙醇,使φ(乙醇)=70%,静置6 h。     

发酵茯苓菌丝体和天然茯苓多糖的研究

本文对发酵茯苓菌丝体和天然茯苓中多糖的提取分离进行了研究,并分别测定了二者总多糖的提取率及总糖的平均含量。发酵茯苓菌丝体和天然茯苓中总多糖的提取率分别为24.47%和82.93%;发酵茯苓菌丝体和天然茯苓总糖的平均含量分别为45.17%和87.24%。     

猴头菌丝多糖降血糖作用研究

目的:研究猴头菌丝多糖的降血糖作用。方法:以液体发酵生产的猴头菌丝体为原料,经热水浸提、浓缩、酒精沉淀获得菌丝粗多糖;以常规降糖药物格列本脲为阳性治疗对照,通过四氧嘧啶诱发小鼠糖尿病的预防试验,比较猴头菌丝多糖各剂量与格列本脲的降血糖效果。结果:猴头菌丝多糖得率为7.14%,粗多糖再经Sevage法去除蛋白质,获得猴头菌丝精多糖(HMP),得率为10.92%;猴头多糖高、中、低三个剂量均能有效的对抗四氧嘧啶诱发的高血糖;其中,高剂量的降血糖作用与格列本脲相比,差异极显著。结论:猴头菌丝多糖对四氧嘧啶型高血糖模型小鼠有降血糖作用,作用效果优于格列本脲,对糖尿病小鼠的胰腺具有一定的保护作用。     

Ca-transport in sea urchin unfertilized eggs: Regulation by endogenous sulfated polysaccharides and K

Previous data from our laboratory showed that the reticulum of the sea cucumber smooth muscle body wall retains both a sarco/endoplasmic reticulum Ca²⁺-ATPase (SERCA) and a sulfated polysaccharide. In this invertebrate, the transport of Ca²⁺ by the SERCA is naturally inhibited by these endogenous sulfated polysaccharides. The inhibition is reverted by K⁺ leading to an enhancement of the Ca²⁺ transport rate. We now show that vesicles derived from the endoplasmic reticulum of unfertilized eggs from the sea urchin Arbacia lixula retain a SERCA that is able to transport Ca²⁺ at the expense of ATP hydrolysis. As described for the sea cucumber SERCA isoform, the enzyme from the sea urchin is activated by K⁺ but not by Li⁺ and is inhibited by thapsigargin, a specific inhibitor of SERCA. A new sulfated polysaccharide was identified in the sea urchin eggs reticulum composed mainly by galactose, glucose, hexosamine and manose. After extraction and purification, this sulfated polysaccharide was able to inhibit the mammal SERCA isoform found in rabbit skeletal muscle and the inhibition is reversed by K⁺. These data suggest that the regulation of the SERCA pump by K⁺ and sulfated polysaccharides is not restricted to few marine invertebrates but is widespread.