海藻糖对NaCl胁迫下番茄种子萌发的缓解效应

以番茄为试材,利用不同浓度的NaCl溶液和海藻糖溶液处理番茄种子,测定发芽率、发芽势、发芽指数和活力指数。结果表明:随着盐分浓度水平的增高,番茄种子发芽能力逐渐下降,超过0.3%浓度后发芽指标下降显著;在0.3%盐胁迫下,不同浓度海藻糖对番茄种子萌发缓解作用不明显;在0.4%盐胁迫下,0.4%浓度海藻糖对活力指数提高显著,而发芽率、发芽势、发芽指数的提高均不显著,表明海藻糖在0.4%浓度时对盐胁迫具有缓解效应。     

谷氨酸棒杆菌麦芽寡糖基海藻糖水解酶基因的克隆与表达

从谷氨酸棒杆菌(Corynebacterium glutamicum)基因组中克隆到麦芽寡糖基海藻糖水解酶基因(treZ),将其插入大肠杆菌表达载体pRSET-B并转化宿主菌E.coli BL21(DE3)pLysS获得重组基因工程菌。经IPTG诱导表达,得到麦芽寡糖基海藻糖水解酶,溶解表达的目的蛋白约占胞内总蛋白的40%,有部分目的蛋白形成包涵体。经薄层层析与离子色谱共同检测证实,该麦芽寡糖基海藻糖水解酶(MTHase)与麦芽寡糖基海藻糖合成酶(MTSase)共同作用于糊精溶液,可得到产物海藻糖,具有工业应用前景。     

布拉酵母菌海藻糖提取方法的比较研究

本试验对布拉酵母菌海藻糖提取方法做了初步研究,通过3种提取剂,采用单一及复合处理方法,摸索出布拉酵母菌海藻糖提取的最佳方法是以5%的三氯乙酸做提取剂,超声破碎10 min后100℃水浴30 min。提取后用5%盐酸水解提取液,然后用生物传感器测定葡萄糖含量,计算海藻糖含量。     

枯叶蛱蝶非滞育成虫和越冬成虫体内糖类物质含量变化

为系统了解枯叶蛱蝶(Kallima inachus Doubleday)滞育特性,利用蒽酮比色法,测定了非滞育成虫和越冬成虫体内不同时期海藻糖和糖原含量.结果表明,非滞育成虫海藻糖含量在0.0363～4.7493 mg/g之间;越冬期间在海藻糖含量在4.479～32.6927 mg/g之间;非滞育成虫糖原含量在0.4633～1.881 mg/g之间,越冬期间在5.072～28.6703 mg/g之间.非滞育成虫体内海藻糖和糖原含量均较低,越冬成虫含量相对较高.海藻糖和糖原代谢与气温和滞育发育阶段有关;越冬初期存在海藻糖和糖原积累,越冬期间两者间存在相互转化.枯叶蛱蝶为海藻糖积累型.     

海藻酸钙固定麦芽寡糖基海藻糖合酶的研究

比较麦芽寡糖基海藻糖合酶(MTSase)与其固定化酶的最适反应pH值、pH稳定性、最适反应温度和热稳定性。结果表明,固定化酶的最适反应pH值(5.5)较原酶(6.0)低,最适反应温度(65℃)较原酶(60℃)高,pH稳定性和热稳定性均较原酶高。     

Protective roles of trehalose in Pleurotus pulmonarius during heat stress response

High temperature is one of the major abiotic stresses that limit edible mushroom growth and development. The understanding of physiological alterations in response to heat stress and the corresponding mechanisms involved is vital for the breeding of heat-resistant edible mushroom strains. Although trehalose functions as a protectant against abiotic stresses in fungi, the putative role of trehalose in thermotolerance remains to be elucidated. In this study, we found heat stress inhibited the growth of two Pleurotus pulmonarius strains, heat-sensitive and less-sensitive, and the inhibition was more significant for the sensitive strain. Heat stress leads to the increase of lipid peroxidation and intracellular trehalose accumulation, with a higher level in the heat-sensitive strain, and this effect is independent of exogenous trehalose application. In addition, a lower concentration of exogenous trehalose application in sensitive strain than in less-sensitive strain was found to alleviate the inhibition of mycelium growth and further increase the intracellular trehalose concentration by heat stress. Thus, the protective effects of trehalose were more remarkable in the sensitive strain. The activities of intracellular trehalose metabolic enzymes, i.e., trehalose-6-phosphate synthase, trehalose phosphorylase and neutral trehalase, were determined, and our data indicated that the changes of these enzymes activities in the sensitive strain were more beneficial to accumulate trehalose than that in the less-sensitive strain.     

Thermobifida fusca海藻糖合成酶的定点突变及其动力学性质研究

对Thermobifida fusca海藻糖合成酶(TreS)保守区域的氨基酸残基I224、N242、Q333、E352和N415进行定点突变,结果表明:位点I224、N242、N415突变后酶的活力与野生型TreS相近,E352位点突变后酶的比活力提高为野生型TreS的1.25倍。突变酶的最适温度、pH、Km和Kcat没有明显变化;突变Q333R则使TreS丧失了酶活力。     

氯化胆碱和海藻糖对油菜蕾薹期干旱胁迫的缓解效应研究和耐旱指标筛选

为研究氯化胆碱和海藻糖对油菜蕾薹期干旱胁迫的缓解效应,本试验以5个油菜栽培品种为研究对象,在蕾薹期设置干旱胁迫、干旱胁迫下添加氯化胆碱及干旱胁迫下添加海藻糖3个处理,通过考察15个耐旱指标,探究不同处理对油菜蕾薹期形态、生长发育和生理特性的影响,并对3种处理下的油菜耐旱性进行综合评价和耐旱指标筛选。结果表明,干旱胁迫导致油菜株高、茎粗、总鲜重、地上部鲜重、超氧化物歧化酶(SOD)活性显著下降,可溶性蛋白、脯氨酸、丙二醛(MDA)含量极显著上升。添加氯化胆碱后,可溶性蛋白含量显著下降(34.96%);添加海藻糖处理后,SOD、过氧化物酶(POD)活性极显著升高(77.22%和183.93%),MDA和可溶性蛋白含量均极显著降低(64.68%和27.68%)。耐旱性效应综合评价表明,干旱胁迫下,淮油18号耐旱性最强(D=0.706),南农油3号耐旱性中等(D=0.476),秦优33、秦油10号和美国油王999耐旱性最差(D=0.364~0.404)。添加氯化胆碱(D值平均提高40.00%)较海藻糖(D值平均提高13.95%)起到更好的抵御干旱逆境的作用。本研究筛选出的根长、茎粗、总鲜重、根鲜重、地上部干重和总干重等指标,可作为油菜抗旱特性快速鉴定的指标(R²=0.992)。综上所述,外源氯化胆碱对干旱胁迫下蕾薹期油菜有更好的缓解作用,这为油菜的耐旱栽培提供了理论依据。