红酵母RY-4中虾青素的分离纯化研究

本文主要研究了红酵母RY-4菌株中天然虾青素的提取和纯化工艺。通过各种破壁提取方法的比较分析,得出了酸热法破壁丙酮提取为较经济理想的粗色素提取方法,提取的粗色素油中虾青素含量达51.7%。通过对各种柱层析条件的摸索研究,得出了以硅胶为吸附剂,Ⅴ(石油醚)∶Ⅴ(乙酸乙酯)混和液为洗脱剂梯度洗脱从粗色素油中分离纯化虾青素的方法,所得虾青素纯度达到97%。     

棉阿舒囊霉细胞色素C的纯化、结晶和专一性的比较

棉阿舒囊霉(Ashbya gossypii)细胞色素C可用氯化钠抽提法或乙酸乙酯自溶法从菌体中抽出,经阳离子交换树脂Zeroli*226柱层析、硫酸铵分部沉淀及反透析后,可被纯化和结晶。乙酸乙酯自溶法的抽提得率高于氯化钠抽提法。两种方法抽提及纯化的细胞色素C在电泳中都表I见为均一,但氯化钠抽提之细胞色素C的生物活力略高于用乙酸乙酯抽提的细胞色素C。     

天蓝色链霉菌胞内蓝色素提取方法研究

对天蓝色链霉菌— 10 0胞内蓝色素提取方法进行了研究 ,结果表明碱提取法、SDS法、研磨法的色素提取得率分别为 90 2 %、95 2 %和 54 6 % ;酶水解法的色素提取得率 <30 % ;细胞在pH9缓冲液中自溶 ,浓度为 1/4原发酵浓度 ,4 0℃保温搅拌 4 8h ,色素提取得率为 33 8%。     

毕赤酵母水解工艺的研究

在发酵过程中产生的总体积为30%～40%的毕赤酵母菌体，大部分在发酵后，会直接把酵母菌体排入环境中，不仅浪费资源，还污染环境，因此，实现资源再利用是文章的研究目的。最终结果表明，对毕赤酵母自溶破壁的最佳自溶水解条件为50℃、pH 6.0，作用时间为30 h、4%Na Cl，酵母悬浮液终体积分数为10%。此外，通过对木瓜蛋白酶、中性蛋白酶、碱性蛋白酶和酸性蛋白酶进行研究发现，添加木瓜蛋白酶效果最佳，添加后的酵母水解物氨基氮得率为4.5%，固形物得率为59%，粗蛋白含量为45.38%。     

破壁方法对大肠杆菌AS1.881中天冬氨酸酶的影响研究

研究了表面活性剂和超声波对大肠杆菌AS1 .881中天冬氨酸酶活力的影响。结果显示 ,2 -YT培养基提取的天冬氨酸胞内酶 ,用表面活性剂 (曲那通、十二烷基硫酸钠等 )破壁 ,游离细胞的最高酶活力由报道的 1 6万单位每克湿细胞提高到31 .3万单位每克湿细胞。表面活性剂最佳质量浓度范围为 0 .1 6 %～ 0 .5 8%。在 7KHz超声波强度下破壁 5min ,游离细胞的最高酶活力也能提高到 30万单位每克湿细胞 ,证明表面活性剂和超声波处理胞内酶 ,破壁效果好 ,酶活力提高显著     

法夫酵母生产虾青素发酵条件的研究

方法：分别进行了接种时间、摇床转速、接种量和装液量对法夫酵母细胞生产虾青素摇瓶发酵过程影响的实验,比较了DMSO法、酸热法、碱法和自溶法等破壁方法和提取溶剂之间的差别,测定了法夫酵母生长过程中的生物量、类胡萝卜素产量和培养基中的残糖。结果：确定了最佳的摇瓶发酵条件为：种瓶至发酵摇瓶的接种时间为40h,摇床转速为160r/min,接种量为10%,装液量为50mL;DMSO法和丙酮分别为合适的破壁方法和提取溶剂。结论：初步确定发酵的基本条件,为进行法夫酵母高产虾青素菌种的筛选以及发酵培养基的优化奠定了基础。     

SMMC-7721肝癌细胞67kD层粘连蛋白受体的分离纯化

分离纯化肝癌细胞的 6 7kD层粘连蛋白受体 (6 7LR) ,以便进一步研究 6 7LR的结构、功能及其在肝癌浸润、转移过程中的作用 .以SMMC 772 1肝癌细胞和L 0 2正常肝细胞为材料 ,采用13 1I标记的层粘连蛋白测定其与细胞的结合能力 ;亲和层析法分离纯化层粘连蛋白受体 ,用SDS PAGE、放射自显影及体外竞争结合实验进行鉴定 .在相同条件下SMMC 772 1肝癌细胞与层粘连蛋白特异结合量为 17 5 4± 0 4 9ng 10 5细胞 ,而L 0 2正常肝细胞与层粘连蛋白的特异结合量为 8 36± 0 4 8ng 10 5细胞 .经过亲和层析 ,从SMMC 772 1肝癌细胞和L 0 2正常肝细胞均可获得纯化受体 ,SDS PAGE显示为单一条带 ,分子量为 6 7kD ,放射自显影及体外竞争结合实验表明其具有较强的与层粘连蛋白结合的活性 .体外竞争结合实验表明 ,SMMC 772 1肝癌细胞层粘连蛋白受体 (772 1LnR)的抑制率可达到 96 2 7± 2 2 9% ,而L 0 2正常肝细胞层粘连蛋白受体 (L 0 2LnR)的抑制率为 4 8 71± 3 79% ,这说明 772 1LnR与层粘连蛋白的亲和力明显高于L 0 2LnR(P <0 0 0 1) .结果表明 ,与L 0 2肝细胞比较 ,SMMC 772 1肝癌细胞具有与层粘连蛋白较强结合能力的特异受体 ,并从肝癌细胞膜上分离纯化到与层粘连蛋白有较强亲和力的 6 7LR     

赤芝孢子粉葡聚糖LB-NB的结构与构象(英文)

从破壁赤芝孢子粉的碱提粗多糖中分离纯化得到一个新的葡聚糖 ,命名为LB NB ,Mr为 4 .7× 1 0 4 ,[α]2 1D - 2 4 .52 0(c 0 .81 ,H2 O)。通过核磁共振、全水解、甲基化反应和Smith降解确定其结构为 β D ( 1→ 3)葡聚糖 ,每 4 .4个糖残基的 6位接有单一的端基葡萄糖。根据不同NaOH浓度下旋光度 [α]D 及特性粘度 [η]的变化 ;H2 O Me2 SO体系中特性粘度 [η]和Hug gins常数k′的变化及刚果红实验 ,推测LB NB在水及低浓度NaOH溶液中 ( <0 .0 5mol/L)呈单螺旋构象 ,而在Me2 SO及高NaOH浓度溶液中 ( >0 .1mol/L)中以无规则卷曲结构存在。体外免疫活性筛选表明 ,LB NB能显著促进T细胞的分化增殖 ,但对B细胞无明显作用     

流式细胞术在乳酸菌自溶检测中的应用

【目的】使用流式细胞术(Flow Cytometric)建立一种新的检测方法,可快速筛选自溶度不同的乳酸菌菌株。【方法】菌悬液经20mmol/L的PI-PBS染液在4℃条件下避光染色30min,上流式细胞仪进行测定,检测器激发光波长488nm,检测波长630nm,每个样品收集1×105个细胞,联机使用CellQuest软件分析结果。【结果】阳性染色细胞数与细胞总数之比很好地反映菌液中自溶细胞与非自溶细胞的比例关系,整个检测过程耗时仅为1h左右。【结论】与传统检测方法比较,FCM测定结果稳定可靠,检测时间短,为乳酸菌的自溶特性研究及筛选自溶度不同的菌株用作商业发酵剂提供了便利条件。     

一种人新型基因工程干扰素rh-IFNα-m的高效表达、纯化和活性检测

为实现干扰素 (IFNα m)的高表达与纯化 ,研究其抗病毒、抗增殖活性。应用PCR技术将已构建的IFNα m的高表达基因亚克隆到原核表达载体pBV2 2 0上 ,构建表达质粒 pBV2 2 0 /IFNα m ,转化大肠杆菌DH5α进行表达。表达产物经初步检定以包涵体形式存在 ,包涵体进行变性、复性 ,然后经CM Sepharose FF、DEAE Sepharose FF离子交换层析和Sephacryal HR10 0分子筛纯化 ,获得较纯的干扰素IFNα m。以IFNα 1b为对照 ,在VSV Wish系统上采用细胞病变抑制法 ,测定纯品IFNα m的抗病毒活性。在Hela细胞上用MTT法进行抗增殖实验。结果表明包涵体含量占菌体总蛋白 4 0 % ,纯化的目的蛋白IFNα m纯度在 95 % ,比活高达 1 2 6× 10 7IU/mg ,纯化收率34 4 % ,IFNα m抗病毒活性和IFNα 1b相当 (P >0 0 5 ) ,抗增殖活性高于IFNα 1b(P <0 0 1)。     

Analysis of hyposmolarity-induced taurine efflux pathways in the bullfrog sympathetic ganglia.

Hyposmolarity-induced taurine release was dependent on the decrease in medium osmolarity (5-50%) in the satellite glial cells of the bullfrog sympathetic ganglia. Release of GABA induced by hyposmolarity was much less than that of taurine. Omission of external Cl- replaced with gluconate totally suppressed taurine release, but only slightly suppressed GABA release. Bumetanide and furosemide, blockers of the Na+/K+/2Cl- cotransport system, inhibited taurine release by about 40%. Removal of external Na+ by replacement with choline, or omission of K+, suppressed taurine release by 40%. Antagonists of the Cl-/HCO3 exchange system, SITS, DIDS and niflumic acid, significantly reduced taurine release. The carbonic anhydrase inhibitor, acetazolamide, reduced the taurine release by 34%. Omission of external HCO3 by replacement with HEPES caused a 40% increase in the hyposmolarity-induced taurine release. Hyposmolarity-induced GABA release was not affected by bumetanide or SITS. Chloride channel blockers, 5-nitro-2-(3-phenylpropylamino) benzoic acid (NPPB) and N-phenylanthranilic acid (DPC), practically abolished taurine release. Blockers of K+ channels, clofilium and quinidine, had no effect on the taurine release. The hyposmolarity-induced taurine release was considerably enhanced by a simultaneous increase in external K+. GABA was not mediated by the same transport pathway as that of taurine. These results indicate that Cl- channels may be responsible for the hyposmolarity-induced taurine release, and that Na+/K+/2Cl- cotransporter and Cl-/HCO3 exchanger may contribute to maintain the intracellular Cl- levels higher than those predicted for a passive thermodynamic distribution in the hyposmolarity-induced taurine release.     

Impaired cell volume regulation in taurine deficient cultured astrocytes

Taurine concentration was reduced by 40 and 65%, respectively in rat cerebellar astrocytes grown in a chemically defined medium or in culture medium containing a blocker of taurine transport (GES). Cell volume in these taurine deficient cells was 10%–16% higher than in controls. When challenged by hyposmotic conditions, astrocytes release taurine and this efflux contributes to the volume regulatory decrease observed in these cells. Taurine deficient astrocytes showed a less efficient volume recovery as compared to controls with normal taurine levels. Exposed to 50% hyposmotic medium, astrocytes with normal taurine concentration recovered 60% of their original volume whereas taurine deficient cells recovered only 30–35%. Similarly, in 30% hyposmotic medium, taurine deficient astrocytes recovered only 40% as compared to 75% in controls. No compensatory increases in the efflux of other osmolytes (free amino acids or potassium) were observed during regulatory volume decrease in taurine deficient astrocytes.     

Taurine uptake by cultured human lymphoblastoid cells

Cultured human lymphoblastoid cells take up taurine from the medium by two processes: 1) a temperature-dependent, Na⁺-dependent, saturable “active”-transport system and 2) diffusion. The active transport has properties similar to those reported for taurine transport by other tissues. Apparent K_m is about 25 μM and V_max about 7.2 pmol/min/10⁶ cells; saturation occurs at 100 μM taurine. Uptake is competitively inhibited by the β-amino acids hypotaurine (50% inhibition at 44 μM) and β-alanine (50% at 152 μM), as measured at 50 μM taurine. Taurocyamine inhibits 50% at 260 μM. Chlorpromazine and imipramine are strong uncompetitive inhibitors, giving 50% inhibition at 26 μM and 115 μM, respectively; at these concentrations cellular viability per se is not affected. Ouabain inhibits 40–50% over a concentration range of 4–500 μM. Diffusion of taurine into the cells is proportional to concentration up to 20 mM. However, at the concentration of taurine in human plasma, 40–100 μM, active transport would provide 90% of the taurine taken up.     

Spontaneous and evoked release of [3H]taurine from a P2 subcellular fraction of the rat retina

The effects of spontaneous and evoked [³H]taurine release from a P₂ fraction prepared from rat retinas were studied. The P₂ fraction was preloaded with [³H]taurine under conditions of high-affinity uptake and then examined for [³H]taurine efflux utilizing superfusion techniques. Exposure of the P₂ fraction to high K⁺ (56 mM) evoked a Ca²⁺-independent release of [³H]taurine. Li⁺ (56 mM) and veratridine (100 M) had significantly less effect (8–15% and 15–30%, respectively) on releasing [³H]taurine compared to the K⁺-evoked release. 4-Aminopyridine (1 mM) had no effect on the release of [³H]taurine. The spontaneous release of [³H]taurine was also Ca²⁺-independent. When Na⁺ was omitted from the incubation medium K⁺-evoked [³H]taurine release was inhibited by approximately 40% at the first 5 minute depolarization period but was not affected at a second subsequent 5 minute depolarization period. The spontaneous release of [³H]taurine was inhibited by 60% in the absence of Na⁺. Substitution of Br^– for Cl^– had no effect on the release of either spontaneous or K⁺-evoked [³H]taurine release. However, substitution of the Cl^– with acetate, isethionate, or gluconate decreased K⁺-evoked [³H]taurine release. Addition of taurine to the superfusion medium (homoexchange) resulted in no significant increase in [³H]taurine efflux. The taurine-transport inhibitor guanidinoethanesulfonic acid increased the spontaneous release of [³H]taurine by approximately 40%. These results suggest that the taurine release of [³H]taurine is not simply a reversal of the carrier-mediated uptake system. It also appears that taurine is not released from vesicles within the synaptosomes but does not rule out the possibility that taurine is a neurotransmitter. The data involving chloride substitution with permeant and impermeant anions support the concept that the major portion of [³H]taurine release is due to an osmoregulatory action of taurine while depolarization accounts for only a small portion of [³H]taurine release.     

Taurine is a weak scavenger of peroxynitrite and does not attenuate sodium nitroprusside toxicity to cells in culture

Summary. Many studies have suggested an antioxidant role for taurine, but few studies have directly measured its free radical scavenging activity. The aim of the present study was to directly determine the action of taurine and taurine analogs to inhibit peroxynitrite-mediated oxidation of dihydrorhodamine 123 (DHR) to rhodamine. Taurine was also tested to determine if it could attenuate the toxicity of sodium nitroprusside (SNP) to neuronal cultures. Taurine at concentrations above 30 mM had a modest ability to inhibit peroxynitrite formation derived from SIN-1. Hypotaurine could inhibit peroxynitrite formation from both SIN-1 (↓75%) and SNP (↓50%) at 10 mM. Other taurine analogs (homotaurine, β-alanine & isethionic acid) slightly potentiated DHR oxidation by SIN-1. Short-term (1-hour) treatment of PC12 cultures with either SNP (1–2 mM) or taurine (20–40 mM) appeared to induce cellular proliferation. In contrast, 24-hour treatment with SNP (1 mM) induced cell death. Combination treatments with taurine and SNP appeared to interact in an additive fashion for both cell proliferation and neurotoxic actions. It appears unlikely that taurine is a major endogenous scavenger of peroxynitrite. Received May 9, 2000 Accepted June 13, 2000     

Oxidative stress improvement is associated with increased levels of taurine in CKD patients undergoing lipid-lowering therapy

Lipid-lowering therapy has been reported to reduce several oxidative stress (OS) markers in hypercholesterolemia. Since OS is frequently associated with renal dysfunction, we aimed to investigate the effect of hypolipidemic drugs on oxidative stress and plasma taurine (Tau), a sulfur amino acid with a marked antioxidant effect, in chronic kidney disease (CKD). We enrolled 30 CKD randomized to receive three different hypolipidemic regimens for 12?months: simvastatin alone (40?mg/day) or ezetimibe/simvastatin combined therapy (10/20 or 10/40?mg/day). Low molecular weight (LMW) thiols including homocysteine, cysteine, cysteinylglycine, glutathione, and glutamylcysteine in their reduced and total form and oxidative stress indices as malondialdehyde (MDA) and allantoin/uric acid (All/UA) ratio were also evaluated. Tau concentration significantly increased throughout the therapy. The rise of taurine was more striking for the group with the concomitant administration of ezetimibe/simvastatin 10/40?mg/day (+31.6% after 1?year of therapy). A significant decrease of both MDA and All/UA ratio was observed during therapy for all patients (-19% for both MDA and All/UA ratio) with a more pronounced effect in patients treated with ezetimibe/simvastatin 10/40?mg/day (-26% for MDA and -28% for All/UA ratio). Besides, an increase of thiols reduced forms was found (+20.7% of LMW thiols redox status) with a greater effect in subjects treated with ezetimibe/simvastatin 10/40?mg/day (+24.7%). Moreover, we demonstrated that oxidative stress improvement during therapy was correlated with increased taurine levels. We hypothesize that taurine may be responsible for the oxidative stress improvement observed during lipid-lowering treatment through the reduction of superoxide anion production at the respiratory chain activity level.     

Reduction of phospholemman expression decreases osmosensitive taurine efflux in astrocytes

The role of phospholemman (PLM) in taurine and Cl(-) efflux elicited by 30% hyposmotic solution was studied in cultured cerebellar astrocytes with reduced PLM expression by antisense oligonucleotide (AO) treatment. PLM, a substrate for protein kinases (PK) C and A, is a protein that increases an anion current in Xenopus oocytes and forms taurine-selective channels in lipid bilayers. Taurine contributes as an osmolyte to regulatory volume decrease (RVD) and is highly permeable through PLM channels in bilayers. Two antisense oligonucleotides (AO1 and AO2) effectively decreased the expression of the PLM protein by 40% and 30%, respectively, and markedly reduced [(3)H]taurine efflux by 67% and 62%. AO treatment also decreased the osmosensitive release of Cl(-), followed as (125)I. The inhibition of Cl(-) efflux (23% for AO1 and 13% for AO2) was notably lower than for [(3)H]taurine. The contribution of PKC and PKA in the function of PLM was also evaluated in astrocytes. Pharmacological activation or inhibition of PKC and PKA revealed that the osmosensitive taurine efflux is essentially PKC-independent while (125)I efflux is reduced by the PKC blockers H-7 (21%) and G?6983 (41%). The PKA activator forskolin and dbcAMP increased taurine efflux by 66-70% and (125)I efflux by 21-45%. Norepinephrine increased the osmosensitive taurine efflux at about the same extent as dbcAMP and forskolin, and this was reduced by PKA blockers. These results suggest that PLM plays a role in RVD in astrocytes by predominantly influencing taurine fluxes, which are modulated by PKA but not PKC.     

Taurine depletion increases phosphorylation of a specific protein in the rat retina

Summary Partial depletion of the taurine content in the rat retina was accomplished for up to 22 weeks by introduction of 1.5% guanidinoethanesulfonate (GES) in the drinking water. Taurine levels decreased by 50% after 1 week of GES treatment and by 80% at 16 weeks. Replacement of GES by taurine to the GES-treated rats from week 16 to 22 returned their taurine content to the control value. Whereas addition of taurine (1.5%) to the drinking water of control rats from week 16 to 22 elevated the retinal taurine content to 118% of the control value, the administration of untreated water to GES-treated animals for the 16 to 22 week time period increased the retinal taurine content to only 76% of the control value.The amplitude of the electroretinogram (ERG) b-wave was decreased by 60% after GES-treatment for 16 weeks and maintained this reduced level for up to 22 weeks. Administration of taurine in the drinking water from week 16 to 22 returned the b-wave amplitude to a range not statistically different from the control values whereas the administration of untreated water produced less improvement.After 6 weeks of GES treatment when the retinal taurine content was reduced by 70% and the amplitude of the b-wave was reduced by 50% (extrapolated from Figure 1), phosphorylation of a specific protein with an approximate molecular weight of 20K was increased by 94%. The increased phosphorylation of the ~20K protein observed after GES treatment was reversed when the animals were treated with taurine (1 1/2%) in the drinking water for an additional 6 weeks. There was no change in the phosphorylation of the ~20K protein when animals were treated with taurine for 6 weeks. The data obtained support the theory that taurine may have a regulatory effect on retinal protein phosphorylation.     

Use of alternative protein sources for fishmeal replacement in the diet of largemouth bass (Micropterus salmoides). Part II: effects of supplementation with methionine or taurine on growth,feed utilization,and health

Fishmeal has long been a staple protein feedstuff for fish, but its global shortage and high price have prompted its replacement with alternative sustainable sources. In this experiment involving largemouth bass (a carnivorous fish), a new mixture of feedstuffs (45% poultry byproduct meal, 30% soybean meal, 15% blood meal, and 10% krill shrimp meal) was added to low (14.5%) fishmeal diets along with 0.0%, 0.5% taurine, 0.5% methionine, or 0.5% taurine plus 0.5% methionine (dry matter basis). The positive control diet [65.3% fishmeal (46% crude protein on dry matter basis)] and all low-fishmeal diets contained 40% true protein and 10% lipids. There were 3 tanks per treatment group (20 fish/tank). Fish with the mean initial body weight of 16.6 g were fed to satiety twice daily. Compared with the unsupplemented low-fishmeal group, supplementing either 0.5% methionine or 0.5% methionine plus 0.5% taurine to the low-fishmeal diet improved (P < 0.05) the growth, feed utilization, retention of dietary protein and lipids, and health of largemouth bass, reduced (P < 0.05) the occurrence of black skin syndrome from ~ 40 to ~ 10%. Histological sections of tissues from the fish with black skin syndrome showed retina degeneration, liver damage, and enteritis in the intestine. Compared with methionine supplementation, supplementing 0.5% taurine alone to the low-fishmeal diet did not affect the growth or feed efficiency of fish and had less beneficial effects (P < 0.05) on ameliorating the black skin syndrome. These results indicated that: (a) the basal low-fishmeal diet was inadequate in methionine or taurine; and (b) dietary supplementation with methionine was an effective method to improve the growth performance, feed efficiency, and health of largemouth bass. Further studies are warranted to understand the pathogenesis of the black skin syndrome in largemouth bass.

     

Dynamics of the conjugate pattern during the infusion of bile acids into isolated rat liver

The conjugate pattern of biliary [14C]bile acids was investigated in isolated perfused rat livers, which were infused with either [24-14C]cholic acid or [24-14C]chenodeoxycholic acid (40 mumol/h) together with or without taurine or cysteine (80 mumol/h). [14C]Bile acids were chromatographed on a thin-layer plate and the distribution of radioactivity on the plate was measured by radioscanning. The biliary excretion of [14C]bile acids was greater in the infusion with [14C]cholic acid than in the infusion with [14C]chenodeoxycholic acid. Biliary unconjugated [14C]bile acids amounted to about 50% of the total after the infusion with [14C]cholic acid, while only about 10% with [14C]chenodeoxycholic acid. In the initial period of infusion, biliary conjugated [14C]bile acids consisted mostly of the taurine conjugate, which decreased with time and the glycine conjugate increased complementarily. When taurine was simultaneously infused, the decrease in the taurine conjugate was suppressed to some extent. Cysteine infused in place of taurine had a similar influence but was less effective than taurine. The taurine content of liver after the infusion with either of the [14C]bile acids decreased greatly compared with that before the infusion, even when taurine or cysteine was infused simultaneously. The glycine content also decreased after the infusion, but the decrease in glycine was smaller than that in taurine. The results suggest that the conjugate pattern of biliary bile acids in rats depends mainly on the amount of taurine which is supplied to hepatic cells either exogenously from plasma or endogenously within themselves.