坛紫菜凝集素的糖结合专一性和细胞凝集作用

坛紫菜的磷酸盐缓冲液浸取液,经硫酸铵沉淀和DEAE－Sepharose,SephadexG-100二步层析纯化,获得纯化的坛紫菜凝集素（PHL）。该凝集素能与3种单糖（阿拉伯糖,半乳糖,木糖）及麦芽糖专一性结合,其中与麦芽糖结合最强。细胞凝集实验结果显示,PHL能凝集兔,绵羊及鸡红细胞而不能凝集鸭,鸽子及人血红细胞,PHL还能凝集海洋微藻－绿色巴夫藻和淡水微藻－蛋白核小球藻,它们的凝集活性与藻细胞密度有关。不同状态的细菌和酵母细胞对PHL反应不同,表明随着细胞状态的改变,细胞表面的凝集素受体也随之发生变化。     

紫菜和它的生活史

紫菜是重要的食用经济海藻,在我国沿海分布很广,从海南岛一直分布到最北方海滨,常见的有甘紫菜(Porphyra tenera)、条斑紫菜(P.yezoensis)、圆紫菜(P.suborbiculata)、长紫莱(P.dentata)、坛紫菜(P.haitanensis)等近10种。紫菜属(Porphyra)在分类上归属于藻类植物红藻门红毛菜亚纲(Bangioideae)中红毛菜目(Bangiales)的红毛菜科(Bangiaceae)。藻体为由单层或双层细胞组成的膜状体,细胞     

不同温度下CO2浓度增高对坛紫菜生长和叶绿素荧光特性的影响

大气CO2浓度升高对海藻的影响已有许多的研究报道,但鲜见有关温度与CO2相互作用的研究.在4种条件下对坛紫菜进行连续通气培养:(1)15℃+ 390tmol/mol CO2,(2) 15℃+700 μmol/mol CO2,(3) 25℃+390 μmol/mol CO2,(4) 25℃+ 700 μmol/mol CO2.从而探讨这种南方海域重要栽培海藻种类的生长和叶绿素荧光特性对温度和CO2相互作用的响应.结果表明:CO2对坛紫菜的生长的影响具有温度依赖性,在低温生长条件下提高CO2浓度更有利于坛紫菜的生长.CO2对坛紫菜叶绿素a(Chlorophyll a,Chl a)和类胡萝卜素(Carotenoid,Car)的促进作用远大于温度对其产生的影响.相对于25℃的生长温度而言,15℃生长温度下的坛紫菜表现出较高的最大相对电子传递速率(rETRmax),表明坛紫菜在低温环境下有较高的光合潜力;而CO2对坛紫菜的rETRmax没有明显影响.对于在不同测定温度下的光合荧光特性而言,在10-30℃测定温度范围内,在各生长条件下的海藻的rETRmax、光能利用效率(α)和最大光化学量子产量(Fv/Fm)随温度的升高变化不明显;但在较高测定温度下(≥30℃),上述荧光参数显著下降,说明高温易引发海藻光能利用效率和光合能力的下降,这可能与光系统(PS)Ⅱ反应中心活性下调有关.同时,当测定温度大于30℃时,15℃生长条件下的坛紫菜的rETRmax、α和F/Fm值下降趋势远大于25℃生长条件下的坛紫菜的值,表明在低温生长条件下的坛紫菜对短期高温胁迫的适应能力较弱;而在高CO2浓度生长条件下的坛紫菜的rETRmax总是低于正常CO2浓度生长下的值,说明CO2浓度升高会抑制坛紫菜在短期高温条件下的光合电子传递能力.     

扇叶铁线蕨凝集素的糖蛋白特性

扇叶铁线蕨叶片组织经磷酸盐缓冲液浸提,硫酸铵沉淀,再经过DEAE-Sepharose—FF和Sephadex G-100层析纯化,得到扇叶铁线蕨凝集素(AFL)。其凝集活性依赖于Ca^2 和Mn^2 ,经测定AFL,是一种分子质量为22000—22500的糖蛋白,分子中含有4．0％的中性糖,具有很高的耐热性,浓度为37．5μg ml^-1的AFL凝血活性可被甘露糖抑制,卵粘蛋白可完全抑制AFL的凝血活性。浓度为2．34μg ml^-1时引起兔血细胞凝集,并能凝集人的A、B或O型血细胞,对鳖的血细胞没有凝集作用。AFL能凝集藻类细胞、酿酒酵母细胞及经过热处理的枯草芽孢杆菌。在AFL的氨基酸组成中不含Tyr。研究结果表明,该凝集素具有糖蛋白的特性。     

应用超滤技术提取坛紫菜多糖的研究

以截留分子量为50 KD的超滤膜对坛紫菜粗多糖提取液进行超滤分离。结果表明,超滤对坛紫菜粗多糖提取液具有较好的脱色效果,脱色率达91.65%。超滤技术能很好地保留坛紫菜粗多糖中的生理活性物质,浓缩了坛紫菜粗多糖提取物,使粗多糖中总糖含量从超滤前的34.95%提高到52.07%,明显提高了坛紫菜粗多糖的糖含量,同时进一步纯化了样品。     

鸡凝集素的分离纯化与性质研究

鸡菌丝体浸取液依次经硫酸铵分级沉淀,DEAE-Sepharose CL-6B离子交换层析和Sephadex G-100分子筛层析3个主要步骤纯化得到一种凝集素(Termitomyces albu-minosus lectin,简称TAL)。纯化的TAL在聚丙烯酰胺凝胶电泳上显示一条蛋白质着色带。TAL的分子量为89.4kD,亚基分子量为38kD和51kD,提示TAL分子由两个不同亚基组成。TAL具有供血动物种属专一性,使Wistar大鼠红细胞凝集所需TAL最低的浓度为0.49μg/ml。糖抑制试验表明,鸡卵粘蛋白明显抑制TAL的凝血活性。TAL对热不稳定,60℃保温15min活力完全丧失。钙、镁或锰离子对TAL无激活作用。TAL不含不性糖,Glu和Asp含量较高,His和Met含量较低。     

无机碳供应与光照条件对坛紫菜光合功能的影响

海藻群体密度过大常引起海水中CO_2供应和光照强度降低,为探讨这两种环境条件对坛紫菜光合作用的影响,在4种条件下培养坛紫菜,即390μL·L^-1(正常空气)+全日光、20μL·L^-1(低CO_2供应)+全日光、390μL·L^-1+低日光(光照强度为全日光的20%)、20μL·L^-1+低日光,测定藻体的碳酸酐酶活性、光合速率,以及不同温度下开放状态光系统Ⅱ最大量子产量(F_ v'/F _m').结果表明:低CO_2供应和低日光下生长的坛紫菜具有较高的碳酸酐酶活性,并且低日光能够提高海藻最大碳饱和光合放氧速率(V _max).在低日光下,生长在低CO_2海水中的坛紫菜V _max显著低于正常CO_2海水中生长的海藻V _max;在全日光下,低CO_2下生长的海藻V _max却高于正常CO_2下生长的海藻V _max.生长在低CO_2和低日光条件下的海藻在低温(10℃)和高温(30℃)下,藻体的F_ v'/F _m'变化不明显;而生长在390μL·L^-1+全日光环境中的海藻在高温环境下200 min后,藻体的F_ v'/F _m'相比40 min时的F_ v'/F _m'降低76.4%.低CO_2和低日光提高坛紫菜光合无机碳利用能力以及适应短期温度变化的能力,而低CO_2对海藻光合速率的影响与海藻所处光照环境有关.     

狗脊蕨凝集素的分离纯化与部分性质

狗脊蕨叶组织经磷酸缓冲液抽提,硫酸铵分级沉淀,DEAE-Sepharose(fast flow)离子交换层析和Sephadex G-100分子筛层析,获得具有凝集活性的狗脊蕨凝集素.用PAGE和SDS-PAGE检测均显示1条蛋白带,提示狗脊蕨凝集素分子只有一个亚基.Sephadex G-100层析和SDS-PAGE测得其相对分子质量在20 kD左右.该凝集素对红细胞有种属专一性,其凝集活性可被木糖、卵粘蛋白所抑制.狗脊蕨凝集素对热相当稳定,以100℃温度加热10 min仍保存部分凝集活性.凝集活性不依赖于金属离子Mg2 、Ca2 、Mn2 .它的中性糖含量为3.1%,Phe含量较高,His含量较低,不含Tyr和Pro.     

琼胶酶酶解2种紫菜及酶解成分分析

研究琼胶酶对坛紫菜和条斑紫菜的降解作用,以降解获得的还原糖为指标,通过正交试验获得酶解的最佳工艺:料液比为1∶30(V/V),酶与底物比4.0∶2(m L/g),温度38℃,反应时间3 h。在此条件下制备坛紫菜和条斑紫菜酶解液,以两种紫菜酶解前原液作为对照,对其成分进行测定比较。结果表明:坛紫菜和条斑紫菜均可被琼胶酶有效降解,降解后总糖、还原糖、氨基酸态氮、游离氨基酸及可溶性固形物含量均明显增加,尤以总糖和还原糖的增加量最为突出,分别为43.68 mg/g和14.87 mg/g;蛋白质、灰分在酶解前后含量变化不大;根据各物质含量测定结果,坛紫菜的酶解效果优于条斑紫菜,条斑紫菜的呈味氨基酸含量优于坛紫菜,具有较好的风味。     

海藻中清除氧自由基的物质

新鲜海藻的提取液含有超氧物歧化酶（SOD）活性物质,能清除超氧自由基（O2-）。海藻的SOD活性通常为60—280Ug-1FW,而在孔石莼（Ulvapertusa）、江蓠（Gracilariaverrucosa）和凤尾菜（G．eucheumoices）中活性较高,约为300Ug-1FW。一般来说,海藻的SOD活性和稳定性为：绿藻＞红藻＞褐藻。绿藻的SOD以CuZn-型为主,而蓝藻的SOD以Fe-型为主。以江蓠琼枝（Eucheumagelatinae）提取液作PAGE并SOD活性染色时,除了观察到SOD同工酶带之外,还发现在前沿指示剂附近有一区域,此区域与高效自由基清除剂SPD（Superphycodismutas）的电泳行为和对氮蓝四唑（NBT）负染色的抑制相同,可能两者为同一种物质。     

35种鲜花的抗氧化活性

采用了Fe^2 诱发的脂蛋白PUFA过氧化、H2O2诱导的RBC溶血和紫外线（UV）诱发的RBC溶血等3个体外抗氧化实验体系,对映山红（Rhododendron simsii Planch.)等35种鲜花的抗氧化活性进行了测定和比较。结果表明,在所测定的35种鲜花中,4种杜鹃属（Rhododendron L.)植物的花勒抗氧化活性最强。一定浓度白杜鹃[R.mucronatum (Blume)G.Don]花蕾提取液的抗Fe^2 诱发的脂蛋白PUFA过氧化活性明显高于维生素C。     

An integrated process for removing the inhibitors of the prehydrolysis liquor of kraft-based dissolving pulp process via cationic polymer treatment

The prehydrolysis liquor (PHL) of the kraft‐based dissolving pulp production process contains various amounts of hemicelluloses that can be utilized in the production of value‐added products. In this work, a new process was proposed for removing the inhibitors of PHL via employing a flocculation concept to facilitate the utilization of hemicelluloses. Lignin, lignocelluloses/cationic polymer complexes, and possibly ethanol are the main products of this process. This process has been experimentally evaluated with an industrially produced PHL and cationic polymers. The results showed that 16% of lignin, 19% of acetic acid, 43% of furfural, and insignificant amount of sugars were removed from PHL via pretreating PHL with acid and lime at pH 7. Furthermore, by adding 0.4–0.5 mg g^?1 polydiallyldimethylammonium chloride (PDADMAC) or chitosan to the pretreated PHL, 12–14% acetic acid, 40–50% furfural, 5–6% monomeric sugars, and 25% oligomeric sugars were removed from the PHL. The complexes made from these components may be applied as organic fillers in various industries. Alternatively, by adding 1.2 or 1.4 mg g^?1 PDADMAC or chitosan to the pretreated PHL, 30 or 35% of lignin was removed, respectively, which induced complexes that could be used as a fuel source. The composition of the complexes formed was also determined in this work. © 2012 American Institute of Chemical Engineers Biotechnol. Prog., 28: 998–1004, 2012     

鳞毛蕨凝集素的分离纯化与性质

阔鳞鳞毛蕨[Dryopteris championi(Benth.)C.CHr.]的叶片组织经硫酸铵沉淀、活性炭柱及DEAE-SepharoseFF离子交换柱等步骤纯化得到鳞毛蕨凝集素(Dryopteris championi lectin)。纯化的鳞毛蕨凝集素(DCL)在聚丙烯酰胺凝胶电泳上显示1条蛋白质着色带。其中性糖含量高,氨基酸组成中队(苯丙氨酸)含量最高,His(组氨酸)含量最低。对不同动物红细胞及人的不同血型红细胞的凝集有专一性。其凝血活性能被果糖、半乳糖和N-乙酰半乳糖胺所抑制,对温度变化较不敏感,Mn^2 和Mg2 在一定浓度范围能激活其为EDTA-Na2所抑制的活性。     

具有谷胱甘肽过氧化物酶活性的小分子模拟物2-TeCD保护线粒体抵抗氧化损伤

首次合成了一个新的含碲化合物 2 TeCD(二碲桥联环糊精 ) ,并证实其具有谷胱甘肽过氧化物酶 (GPX)活力 ,能清除氢过氧化物 .与其它GPX模拟物相比 ,2 TeCD具有分子量小 ,水溶性好及良好的化学和生物学稳定性 ,且其GPX活力比另一种被广泛认知的小分子模拟物Ebselen高约 4 6倍 .用Fe2 + Vc诱导的线粒体损伤体系研究了 2 TeCD的抗氧化性质 ,结果发现在相同剂量下 2 TeCD较Ebselen具有更强的抗氧化能力     

丹参四倍体优良品系有效成分的含量测定及药理学试验

运用HPLC法测定丹参（Sabuia miltiorrhiza Bunge）同源四倍体优良品系61－2－22及安徽、江苏和陕西产丹参不同部位、不同生长年限的有效成分（3种丹参酮和2种水溶性酚酸）含量。丹参品系61－2－22的有效成分含量明显高于其他产地丹参的含量;根中有效成分含量明显高于茎和叶的含量;丹参酮和丹参素的含量呈明显相关。初步药理实验结果表明,在相同剂量下,优良品系61－2－22具有更好的药理活性。     

泥蚶(Tegillarca granosa Linnaeus)血淋巴液凝集素的分离纯化及其性质研究

泥蚶是一种重要的海产经济贝类,其血淋巴液经硫酸铵二步分级沉淀后,再经Sephadex G- 100凝胶过滤和Sepharose 4B亲和层析纯化制得泥蚶血淋巴液凝集素。经测定,该凝集素分子量约为123Kda,为两个亚基的蛋白质,其相对分子量分别为15 KDa和16 KDa,分子中含5．02％的糖。在氨基酸组成中,天门冬氨酸(Asp)含量最高,其次是谷氨酸(Glu)和组氨酸(His),不含蛋氨酸(Met)。泥蚶血淋巴液凝集素对多种天然或经酶修饰的人或动物红细胞具有不同的凝集作用,其中对兔红细胞的凝集活性最大。半乳糖和乳糖对其凝集活性具有抑制作用。凝集活性依赖于Ca2 ,在pH7．0较稳定,热稳定性不高,在30℃-70℃时凝集效价由原来的25下降为21,当温度超过80℃以后,凝血活性完全丧失。     

A process for purifying xylosugars of pre-hydrolysis liquor from kraft-based dissolving pulp production process

Background

In the kraft-based dissolving pulp production process, pre-hydrolysis liquor (PHL) is produced, which contains hemicelluloses, lignin, furfural and acetic acid. PHL is currently burned in the recovery boiler of the kraft pulping process, but it can be utilized for the generation of high-valued products, such as xylitol and xylanase, via fermentation processes. However, some PHL constituents, e.g., furfural and lignin, are contaminants for fermentation processes and they must be eliminated for production of value-added products.

Results

In this work, a process is introduced for removing contaminants of PHL. Ca(OH)₂ treatment is the first step of this process, which removed 41.2% of lignin and negligible amount of sugars. In this step, a notable increase in the concentration of acetic acid was achieved (ranging from 6.2 to 11.7 g/L). In the second step, the implementation of adsorption using activated carbon (AC) at 1 wt% dosage led to additional 32% lignin and 5.9% xylosugar removals. In addition, laccase assisted activated carbon treatment led to further removal of lignin via accelerating lignin polymerization and adsorption on AC (i.e., removal from PHL). Overall, 90.7% of lignin, 100% of furfural, 5.7% of xylose, and 12% of xylan were removed from PHL, while the concentration of acetic acid became twofolds in the PHL.

Conclusions

This study reports an attractive process for purifying sugars and acetic acid of PHL. This process may be implemented for producing sugar-based value-added products from PHL. It also discusses the mechanism of Ca(OH)₂ treatment, AC adsorption and laccase assisted activated carbon treatment for lignin removal.

     

Suppression of voluntary ethanol consumption in rats by gamma-butyrolactone

The effect of gamma-butyrolactone (GBL) on voluntary ethanol intake was studied in a group of Wistar rats in which a stable preference had been induced by exposure to increasing ethanol concentrations. These rats drank 60% of their daily fluid intake as 15% ethanol solution, corresponding to about 6 g ethanol/kg/day. GBL, injected intraperitoneally at the dose of 200 mg/kg, twice daily for 3 consecutive days, decreased ethanol intake by about 80% on the days of treatment, but did not reduce total fluid intake. Ethanol intake remained significantly reduced up to the 5th day following cessation of GBL administration. GBL, up to a concentration of 10(-3) M, inhibited neither alcohol-dehydrogenase nor aldehyde-dehydrogenase in rat liver homogenates, nor dopamine-beta-hydroxylase in homogenates of adrenal medulla or hypothalamus of rats. It is suggested that inhibition of firing in dopaminergic neurons mediates the suppressant effect of GBL on ethanol preference.     

Effects of phenylalanine and its deaminated metabolites on Na+, K+-ATPase activity in synaptosomes from rat brain

The effects of phenylalanine (PHE) and its deaminated metabolites phenylpyruvate (PHP), phenyllactate (PHL) and phenylacetate (PHA) on sodium and potassium activated adenosinetriphosphatase (Na⁺, K⁺-ATPase) in synaptosomes from rat brain were investigated. At very low concentrations (5–10 M), PHE, PHL and PHA inhibited the activity, while PHP stimulated the activity. At intermediate concentrations (50–100 M), all compounds had no effect, but at higher (0.5–1.0 mM) concentrations they inhibited the enzyme activity. Thus all the compounds tested showed a biphasic effect on the enzyme activity. Hydroxylamine inhibited the Na⁺, K⁺-ATPase activity when present alone; simultaneous addition of hydroxylamine and PHE, however, eliminated the inhibitory effects of each other. Reversal of mutual inhibition also occurred in the presence of hydroxylamine and very low (5–10 M) concentrations of PHL or PHA. The inhibitory effects of PHE at all concentrations, and of PHL or PHA at low concentrations, were also eliminated in the presence of EGTA. The data indicate that inhibition of brain membrane Na⁺, K⁺-ATPase by PHE and by low concentrations of PHL and PHA may involve metal ions, but that the inhibition by high concentrations of these metabolites must occur by a different mechanism. Since Na⁺, K⁺-ATPase plays a central role in neuronal function, and the presence of excess PHE and its deaminated metabolites occurs in brain tissue under conditions of experimentally induced hyperphenylalaninemia and genetic phenylketonuria, the neurologic impairment in experimental and genetic PKU may in part be related to the deleterious effects of these compounds on brain ATPase.     

RARβ在胃癌细胞生长调节中的作用

为探讨 RARβ受体介导全反式视黄酸 ( ATRA)抑制胃癌细胞生长的作用机理 ,用 Northern印迹测定 RARβ m RNA表达水平 ,脂质体介导的转染方法将含有 RARβ基因的表达载体转染MKN- 45细胞并稳定表达 ,MTT和软琼脂集落形成等实验测定细胞生长速率和生长状态 ,氯霉素乙酰转移酶活性 ( CAT)测定视黄酸应答元件βRARE的转录活性以及 AP- 1 ( activator protein- 1 )活性 .RARβ在 ATRA敏感细胞株 MGC80 - 3、BGC- 82 3和 SGC- 790 1中表达 ,而在 ATRA抗性细胞株 MKN- 45中不表达 .当 RARβ基因转染 MKN- 45细胞时 ,细胞变为 ATRA敏感 ,由此导致ATRA抑制 MKN- 45细胞生长和软琼脂集落形成 .ATRA可以加强诱导 MGC80 - 3、BGC- 82 3和SGC- 790 1细胞βRARE的转录活性 ,但对 MKN- 45细胞影响不大 ,不能抑制细胞 AP- 1活性 .当RARβ基因转染 MKN- 45细胞后 ,ATRA则能够诱导细胞 βRARE的转录活性 ,并抑制细胞的 AP-1活性 .RARβ表达与 ATRA抑制胃癌细胞生长密切相关 .ATRA诱导 βRARE转录活性和抑制AP- 1活性可能是其调控胃癌细胞生长的机制之一 .