柱前衍生化-HPLC检测亚氨基二乙酸法制备双甘膦反应进程的研究

[目的]建立一种利用亚氨基二乙酸制备双甘膦的新检测方法。[方法]以9-芴基甲氧羰酰氯为衍生化试剂对合成双甘膦的反应物进行衍生化。采用Gemini C_(18)(150.0 mm×4.6 mm,5.0μm)色谱柱,室温下以0.05 mol/L NaH_2PO_4(pH=3.5)溶液-乙腈(V/V,60∶40)为流动相,流速为1.0 m L/min,检测波长265 nm,对反应液中的亚氨基二乙腈、亚氨基二乙酸和氨气衍生物进行分离检测。[结果]反应液中的亚氨基二乙腈、亚氨基二乙酸和氨气衍生物,分别在0.02~1.20、0.02~1.20、0.10~2.00 mg/m L浓度范围内呈现良好的线性关系(r≥0.999 8),检出限分别为0.000 4、0.000 4、0.003 0 mg/m L,加样回收率分别为99.96%、99.86%、99.89%,相对标准偏差均不超过1.6%。[结论]该研究建立的方法可用于亚氨基二乙酸法制备双甘膦反应体系的跟踪分析。     

D-核糖发酵条件的优化与中试

[目的]研究利用枯草芽孢杆菌的莽草酸营养缺陷型突变株发酵生产D-核糖的发酵条件。[方法]以枯草芽孢杆菌CB．sems-10为出发菌株,通过正交试验得出最佳培养基配方并利用种子罐和发酵罐对发酵条件进行了中试试验。[结果]单因素试验表明,接种量为10％时,D．核糖产率最高;发酵前期的适宜pH值约为7．2,发酵中后期的适宜pH值在偏酸性范围内;37℃下D-核糖的产率最高;摇床转速为170r／min时,D-核糖的产率最高。极差分析表明,各因素对D-核糖产率的影响依次为：酵母粉〉（NH。）,SO4〉玉米糖〉Mn-SO4〉玉米浆。最佳培养基配方为：玉米糖20％＋酵母粉0．6％＋（NH4）：SO40．5％＋MnSO40．05％,最佳pH值为7．2。枯草芽孢杆菌CB．sems-10的适应能力强,转糖率高,其平均D-核糖产率为108．6mg／L,最高达127．1mg／L。[结论]该研究为利用枯草芽孢杆菌CB．sems．10发酵生产D-核糖奠定了理论基础。     

Potato tuber sugars, starch and organic acids in relation to ozone exposure

Summary Data from two Swedish and one Finnish open-top chamber experiments were combined to investigate effects of ozone exposure on potato (Solanum tuberosum L.) tuber content of starch, sucrose, fructose, glucose, malic, citric and ascorbic acids. The glucose, fructose and malic acid concentrations showed strong negative correlations with ozone exposure, while citric acid, consistently increased with ozone exposure. No ozone effects could be demonstrated on starch, sucrose or ascorbic acid concentrations. It is discussed to what extent the changes found in potato tuber composition can be explained in terms of ozone effects on tuber maturity. Ozone exposure was expressed as the accumulated exposure over a cut-off concentration of 40 nmol mol⁻¹ (AOT40) and as the accumulated uptake of ozone over an ozone uptake rate threshold of 7 nmol m⁻² s⁻¹ (CUO 7). The difference in ability of the exposure indices to explain observed effects was small.     

Activity of polygalacturonases from Moniliophthora perniciosa depends on fungus culture conditions and is enhanced by Theobroma cacao extracts

We report the first analysis of polygalacturonase regulation in the basidiomycete Moniliophthora perniciosa. Non-secreted and secreted polygalacturonase activity was obtained from M. perniciosa cultivated on bran-based solid medium or liquid media containing additional carbon sources or cacao extracts (infected or not by the fungus). Polygalacturonase activity assays were carried out under different temperatures and incubation periods. The best secreted polygalacturonase activity was obtained when the enzymatic assay was made at 50 °C for 10 min. Moreover, the polygalacturonase activity was enhanced when the fungus was cultivated on potato dextrose medium, in the presence of additional fermentable carbon sources, in the presence of cacao pulp or non infected cacao extracts.     

耕作方式对黑土有机碳及有机无机复合状况的影响

[目的]研究耕作方式对黑土有机碳数量的变化、有机无机复合度及腐殖质结合形态的影响。[方法]采用设置休闲、玉米连作和玉米—大豆轮作3种耕作方式进行长期定位试验。[结果]不同耕作方式对黑土有机无机复合状况有明显的影响。休闲、连作及轮作均能增加土壤有机碳及其各组分、重组有机碳含量以及原土复合量,提高土壤活性有机碳含量,降低土壤有机碳的氧化稳定性及原土复合度。连作和轮作增加黑土土壤追加复合量和追加复合度,以轮作效果最好。不同耕作方式中各种结合形态的腐殖质在绝对含量上均有明显提高,以松结合态腐殖质增加较多。[结论]轮作更有利于提高土壤HA/FA比值、HA的E4/E6比值、土壤松结合态腐殖质含量及土壤重组腐殖质碳的松/稳和松/紧比值。     

蚯蚓蛋白水解酶对大豆蛋白的分解作用

通过琼脂糖蛋白平板及水解度测定两种方法从定性、定量两个方面研究了蚯蚓蛋白水解酶对大豆蛋白的分解作用．同时测定并比较了蚯蚓豆粕反应物的氨基酸含量。结果表明．蚯蚓蛋白水解酶对大豆蛋白具有一定的酶解活性．其水解度达2．75％。利用蚯蚓处理豆粕,反应物中多种氨基酸含量均有不同程度增加,氨基酸总量与豆粕相比上升了27．83％,而且各种必需氨基酸的比例也更趋合理。因此,利用蚯蚓蛋白水解酶对大豆蛋白的分解作用可以有效地改善豆粕饲料的品质．     

盐胁迫对樱桃番茄风味品质的影响

为探究盐分胁迫对樱桃番茄(Lycopersicon esculentum Mill. var. cerasiforme Alef)风味的影响,本研究以樱桃5号为试验材料,探究了不同含盐量[T1:0.05 g·kg^-1(CK)、T2:1.5 g·kg^-1、T3:3 g·kg^-1、T4:4.5 g·kg^-1、T5:6 g·kg^-1]土壤条件下果实糖、酸、氨基酸、芳香类物质含量的变化。结果表明,各处理果实中果糖和葡萄糖含量较高,占糖类物质总量的94.88%~95.97%;盐胁迫能促进果实中糖类物质的积累,其中果糖在T5含量最高,较对照增加了18.34%,葡萄糖在T3含量最高,较对照显著增加了29.06%。果实中有机酸以柠檬酸和苹果酸为主,占总量的88.30%~91.60%,随着盐分的增加有机酸含量呈先升高后降低的趋势,柠檬酸和苹果酸含量均在T3最高,分别较对照显著增加了61.40%和129.90%,且有机酸总含量是对照的1.71倍。盐胁迫对樱桃番茄的氨基酸含量也有一定影响,盐胁迫处理果实中谷氨酸和天冬氨酸含量较高;除蛋氨酸外,各氨基酸含量均以T3最高。各处理果实中共检出47种芳香物质,其中醛类12种、酮类5种、醇类14种、酯类3种;盐胁迫处理番茄果实中芳香物质的种类较多,且相对含量高,其中2-已烯醛、香叶基丙酮、2-异丁基噻唑含量与对照有明显差异,是盐胁迫下影响番茄风味的重要芳香物质。本研究结果为盐胁迫提升樱桃番茄风味品质提供了数据支撑。     

Link between Domoic Acid Production and Cell Physiology after Exchange of Bacterial Communities between Toxic Pseudo-nitzschia multiseries and Non-Toxic Pseudo-nitzschia delicatissima

Bacteria are known to influence domoic acid (DA) production by Pseudo-nitzschia spp., but the link between DA production and physiology of diatoms requires more investigation. We compared a toxic P. multiseries to a non-toxic P. delicatissima, investigating links between DA production, physiological parameters, and co-occurring bacteria. Bacterial communities in cultures of both species were reduced by antibiotic treatment, and each of the diatoms was inoculated with the bacterial community of the other species. The physiology of P. delicatissima was minimally affected by the absence of bacteria or the presence of alien bacteria, and no DA was detected. P. multiseries grew faster without bacteria, did not produce a significant amount of DA, and exhibited physiological characteristics of healthy cells. When grown with alien bacteria, P. multiseries did not grow and produced more DA; the physiology of these cells was affected, with decreases in chlorophyll content and photosynthetic efficiency, an increase in esterase activity, and almost 50% mortality of the cells. The alien bacterial community had morphological and cellular characteristics very different from the original bacteria, and the number of free-living bacteria per algal cell was much higher, suggesting the involvement of bacteria in DA production.     

金丝小枣插条中外源激素与内源激素的关系

该文从生理生化的角度对外源生长素（ＮＡＡ）在金丝小枣嫩枝插穗中的作用进行了研究。实验结果表明，外源生长素（ＮＡＡ）影响插条内的生理生化反应，大大提高了插条内源生长素（ＩＡＡ）的含量，同时能够维持内源脱落酸（ＡＢＡ）含量保持在一定的水平，调节了内源激素ＩＡＡ和ＡＢＡ两者之间的动态平衡，使得ＩＡＡ／ＡＢＡ值保持基本稳定；说明两者之间有着一定的协调作用，内源ＩＡＡ很大程序上影响形成层处细胞，使其分化出根原始细胞。     

Fat-1基因载体构建及其在家鸡中的体外表达

试验旨在构建一种适合于家禽体外表达的ω-3脂肪酸脱氢酶Fat-1基因的真核生物表达载体,为后续转基因鸡的生产奠定基础。根据家鸡密码子使用频率,对秀丽隐杆线虫Fat-1基因进行优化改造;将改造后的Fat-1基因(cFat-1)连接至pLL3.7表达载体,构建重组质粒pLL3.7-cFat-1;经PCR、酶切、序列分析等手段对重组质粒进行鉴定;用胰酶消化法培养鸡成纤维细胞,利用TurboFect^TM转染试剂将pLL3.7-cFat-1转染体外培养的成纤维细胞;通过RT-PCR检测和绿色荧光观察分析cFat-1基因在细胞中的表达。结果表明cFat-1基因在鸡成纤维细胞中高效转录并表达,成功构建了可在家禽体外表达cFat-1基因的特异性表达载体。本研究首次获得可在家禽体外表达cFat-1基因的转基因细胞系,证实了经基因改造后cFat-1基因可在家禽体外的高效转录和表达,为后续制备富含ω-3脂肪酸的转基因鸡奠定基础。