以蛤蜊壳为钙源的L-焦谷氨酸钙制备工艺

目的 为了高值化利用海洋生物资源,以蛤蜊加工产生的大量废弃物——蛤蜊壳为钙源制备L-焦谷氨酸钙。方法 蛤蜊壳经去除附着物、粉碎、水飞法处理等预处理步骤制成粉末状钙源蛤蜊壳粉,使之与L-焦谷氨酸直接进行合成反应合成L-焦谷氨酸钙。为了获得最佳工艺条件,在蛤蜊壳粉过量的前提下,采用正交设计法考察了反应温度、反应时间对L-焦谷氨酸钙产量的影响,筛选了L-焦谷氨酸钙分离方法。结果 在反应温度为60 ℃,反应时间为3 h,采用真空浓缩到一定程度后再用95%乙醇使其结晶和重结晶,焦谷氨酸钙的产率最大可达88.82%。结论 该工艺具有工艺简便、耗能少、产率高等特点,既可以将蛤蜊壳高值化利用制得性能优良的补钙健脑食品,又能解决蛤蜊壳对环境的污染问题。     

四角蛤蜊壳制备L-天门冬氨酸螯合钙工艺及表征研究

目的 以废弃物四角蛤蜊贝壳为钙源,经过中药煅法炮制后,与L-天门冬氨酸制备氨基酸螯合钙。方法 以得率和螯合率为指标综合评分考查L-天门冬氨酸与四角蛤蜊贝壳的螯合工艺并进行优化,且通过红外和差示扫描量热仪等对其产物进行组成表征研究。 结果 确定L-天门冬氨酸螯合钙的最佳螯合工艺：pH=5,反应温度为65℃,反应时间为1.5h,摩尔比（氨基酸:Ca2+）为2:1,且初步研究发现结构为带两个结晶水的螯环结构。 结论 L-天门冬氨酸螯合钙的制备,能有效利用贝壳废弃物,补充人体钙元素和基本氨基酸,为L-天门冬氨酸螯合钙的工业生产提供理论基础。     

响应面法优化河豚鱼皮胶原寡肽螯合锌的制备工艺

目的 优化河豚鱼皮胶原寡肽的制备工艺。方法 以河豚鱼皮为原料,制备河豚鱼皮胶原寡肽螯合锌, 以含锌量为实验指标,研究了pH值、温度、时间、胶原寡肽与锌的摩尔比对螯合反应的影响,在单因素实验的基础上采用4因素3水平的Box-Behnken响应面分析法,对螯合工艺进行优化。结果 在pH 5.3,反应温度70.1℃,反应时间2.9 h,胶原寡肽与硫酸锌的摩尔比2.1:1的优化条件下,制备的胶原寡肽螯合锌的含锌量最高,达到14.18%。红外光谱分析表明,螯合后胶原肽中的C=O,N-H都参与了Zn2 的配位,生成了胶原寡肽螯合锌。结论 响应面法能很好地应用于河豚鱼皮胶原寡肽螯合锌螯合工艺的优化。     

金枪鱼骨胶原蛋白肽螯合钙制备工艺及对MG-63细胞碱性磷酸酶分泌的影响

目的 为获得一种能够增加人成骨细胞碱性磷酸酶生成量的金枪鱼骨胶原蛋白肽螯合钙(collagen peptide from tuna bone chelated calcium, TCP-Ca)的工艺方法。方法 本文利用正交实验优化蛋白酶酶解法制备金枪鱼骨胶原蛋白肽的工艺,利用正交实验优化金枪鱼骨胶原蛋白肽和柠檬酸钙进行螯合反应的工艺,然后利用傅里叶变换红外光谱对TCP-Ca进行定性分析,同时检测TCP-Ca对MG-63细胞碱性磷酸酶生成量的影响。结果 金枪鱼骨胶原蛋白肽制备的最佳工艺为pH 9.0、酶解时间180 min、加酶量5000 U/g、酶解温度45 ℃;TCP-Ca制备的最佳工艺为温度35 ℃、pH 7.5、肽钙质量比6:1、时间40 min;金枪鱼骨胶原蛋白肽的氨基和羟基均参预了钙螯合反应;TCP-Ca比金枪鱼骨胶原蛋白肽更有利于增加MG-63细胞分泌碱性磷酸酶。结论 本文优化了TCP-Ca的制备工艺,发现其具有增加成骨细胞分泌碱性磷酸酶的生物活性。     

茶碱钙的合成

目的合成茶碱钙。方法以茶碱钠盐和氯化钙为原料,通过复分解反应合成茶碱钙,以双氧水为氧化剂精制,合成符合客户要求的茶碱钙。结果及结论茶碱钙合成的最佳工艺条件为茶碱钠盐与氯化钙的摩尔配比为1∶0.52,反应温度为65℃左右,pH为原茶碱钠盐水溶液的pH10～11,双氧水用量为0.5g。     

DL-对羟基苯甘氨酸的制备研究

目的研究一步法催化合成DL-对羟基苯甘氨酸的合成条件。方法对原料配比、反应时间、反应温度、催化剂用量四个因素进行考察,得到最佳反应条件。结果所得较佳工艺条件为：乙醛酸∶苯酚：氨基磺酸为1∶1.2∶1.3（摩尔）,反应时间为8h,反应温度为70℃,催化剂用量为乙醛酸的2%,产品收率达70%以上。结论 DL-对羟基苯甘氨酸的制备研究方法可行。     

马来酸氨氯地平合成工艺的改进

对马来酸氨氯地平的成盐工艺作了进一步的改进。着重探讨了反应原料配比、反应温度、反应时间和精制溶剂对产率的影响,从而得到最佳反应条件。     

硫化钙碳酸化制备硫化氢工艺参数的研究

研究了以磷石膏为原料烧制硫化钙和碳酸化硫化钙生产硫化氢的工艺路线,并用正交设计法找出了硫化钙碳酸化制备硫化氢的最优工艺参数.通过实验得到最优工艺参数为气流速度110个气泡/min、温度60℃、反应时间5 h,此时硫的转化率达93%.     

硫酸降解甲壳素制备N－乙酰氨基葡萄糖的工艺研究

本文以甲壳素为原料,采用硫酸水解工艺制备N－乙酰氨基葡萄糖,研究硫酸浓度、反应时间、反应温度、硫酸加入量等影响因素对N－乙酰氨基葡萄糖产率的影响,确认硫酸浓度70％、反应温度50℃、反应时间7h、硫酸加入体积为甲壳素质量2倍的条件为比较适宜的反应条件,为本工艺产业化提供可靠的参考数据。     

聚磷酸铵的合成

研究了在常压条件下以湿法磷酸生产的工业级磷酸一铵和尿素为原料生产聚磷酸铵(APP)的合成工艺条件,制备了平均聚合度为400的聚磷酸铵.研究了磷酸铵、反应温度、组分配比、反应时间对平均聚合度的影响.结果表明,高聚合度APP的优惠生产工艺条件为:尿素与磷酸一铵的摩尔比为2,聚合温度为300℃,聚合时间为3h.聚合反应完成后,冷却,即得粉末状的APP聚合物.     

牡蛎营养钙粉促进断乳大鼠生长发育的实验研究

目的对牡蛎营养钙粉促进断乳大鼠生长发育的作用进行实验研究。方法参考《保健食品检验与评价技术规范》中的改善生长发育功能检验方法进行实验,检测大鼠体重、身长和食物利用率等指标。结果牡蛎营养钙粉能显著增加大鼠体重、身长和食物利用率。结论牡蛎营养钙粉具有促进断乳大鼠生长发育的作用。     

Antagonism by riluzole of entry of calcium evoked by NMDA and veratridine in rat cultured granule cells: evidence for a dual mechanism of action.

1. Intracellular calcium levels were measured in cultured cerebellar granule cells of the rat by use of the fluorescent dye, indo-1/AM. 2. Intracellular calcium levels were increased by depolarizing stimuli such as N-methyl-D-aspartate (NMDA) (100 microM), glutamic acid (20 microM), and veratridine (10 microM). This increase was essentially due to entry of external calcium. 3. Riluzole (10 microM) blocked responses to all the depolarizing agents. 4. Riluzole could still block the increase in intracellular calcium evoked by NMDA or glutamic acid when sodium channels were blocked by tetrodotoxin, suggesting that this effect is not mediated by a direct action of riluzole on the voltage-dependent sodium channel. 5. Pretreatment of the cells with pertussis toxin (0.1 micrograms ml-1) did not modify the increases in intracellular calcium evoked by NMDA, glutamic acid or veratridine. 6. In pertussis toxin-treated cells, riluzole could no longer block responses to excitatory amino acids, but still blocked responses to veratridine. 7. It is concluded that riluzole has a dual action on cerebellar granule cells, both blocking voltage-dependent sodium channels and interfering with NMDA receptor-mediated responses via a pertussis toxin-sensitive mechanism. Furthermore, these two processes have been shown to be independent.     

四角蛤蜊贝壳制备柠檬酸钙的工艺研究

目的以四角蛤蜊贝壳为钙源,制备高附加值柠檬酸钙。方法在单因素的基础上结合三因素三水平的响应面设计分析方法,建立制备柠檬酸钙的二次多项式数学模型,得到柠檬酸钙最佳制备工艺。结果与结论酸钙比2.78、液固比6.11、反应时间1.9h,在此条件下,柠檬酸钙的得率为91.93%,纯度为99.03%。制备出的柠檬酸钙为白色粉末状固体,并用傅立叶变换红外光谱仪及电感耦合等离子发射光谱仪,对其进行定性表征及定量分析,表明用四角蛤蜊贝壳制备柠檬酸钙是可行的。     

钙化条件对海藻酸钙空心硬胶囊成型性的影响

目的研究钙化条件对空心硬胶囊成型的影响。方法以海藻酸钠为主要原料,采用两次钙化法制备了海藻酸钙空心硬胶囊。结果与结论当第一次钙化钙源为葡萄糖酸钙,钙化温度、时间和浓度分别为40℃、4min和4%时,第二次钙化钙源为乳酸钙,钙化温度、时间和浓度分别为25℃、20min和6%的条件下,胶囊的成型性最好。     

Antibody-conjugated soybean oil-filled calcium phosphate nanoshells for targetted delivery of hydrophobic molecules

Hollow calcium phosphate nanoparticles capable of encapsulating poorly water-soluble molecules were produced by self-assembly. Previously reported were solid calcium phosphate nanoparticles and water-filled calcium phosphate nanocapsules suited for encapsulating mostly hydrophilic, but not hydrophobic compounds. Here, calcium phosphate was deposited around 100?nm diameter, 1,2-dioleoyl-sn-glycero-3-phosphate stabilized soybean oil nanoemulsions using either calcium chloride or NaOH titrations to achieve shell thickness between 20–70?nm. The surface was functionalized with carboxylic acid via the addition of carboxyethylphosphonic acid to attach Molecular Probes AB-594C antibody using sulpho-n-hydroxysuccinimide and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride with an efficiency of ～70%, while retaining near complete antibody function. Hydrophobic pyrene was encapsulated with an efficiency of 95%, at concentrations much higher than its water solubility limit, and exhibited spectral features characteristic of a hydrophobic environment. These materials can be used in the targeted delivery of many useful, yet poorly water-soluble pharmaceutical and nutraceutical compounds.     

Effects of depolarizing stimuli on calcium homeostasis in cultured rat motoneurones

1. Intracellular calcium concentrations in individual rat motoneurones in enriched primary cultures were measured by Indo-1 fluorimetry.
2. Motoneurones in the cultures were characterized morphometrically and by cholineacetyltransferase immunocytochemistry.
3. Depolarization of the cells with glutamic acid or veratridine increased intracellular calcium levels, which returned to baseline only slowly after removal of the depolarizing agent.
4. The use of selective agonists (N-methyl-D-aspartic acid, AMPA, kainic acid, quisqualic acid and 1R-3S-ACPD) and antagonists (MK 801 and CNQX) showed that the excitatory amino acid-evoked responses were mediated by AMPA/kainate receptors rather than by NMDA receptors.
5. Depolarization-evoked calcium transients in motoneurones are blocked by the neuroprotective drug riluzole
6. Calcium transients reflected entry of calcium from without the cell, and their blockade by nitrendipine and lanthanum chloride suggested that this entry took place primarily through voltage-dependent calcium channels.
7. These findings may be relevant for understanding the selective vulnerability of motoneurones to excitotoxicity in amyotrophic lateral sclerosis, and the therapeutic activity of riluzole in the treatment of this disease.

     

Domoic acid in Portuguese shellfish and fish.

The presence of domoic acid (DA) in Portuguese shellfish is a recurrent event that affects shellfish resources several times a year, mainly in spring and autumn. Levels of domoic acid as high as twice the regulatory level of 20 microg DA/g tissue are not unusual. When several shellfish species are exploited in the same restricted area, common cockle (Cerastoderma edule) and carpet shell (Venerupis pullastra) are usually amongst the most toxic, followed by peppery furrow shell, clam, mussel, oyster and razor clam. In whole sardine, domoic acid was detected in levels exceeding sometimes the regulatory limit. Fortunately, toxicity is restricted to the gut content, and does not accumulate in muscle tissue. In brain tissue, domoic acid was detected in levels generally below 1 microg/g. Domoic acid was confirmed by spectra acquired with a diode-array detector. The most toxic samples were confirmed by mass spectrometry.     

Different effects of Pb(2+) and Cu(2+) on immune and antioxidant enzyme activities in the mantle of Pinctada fucata

The aim of this study was to investigate the natural role of the mantle in pearl oyster, Pinctada fucata. The mantle is believed to be the tissue responsible for shell and pearl formation. However, our current study on lead and copper accumulation in tissues of the oyster showed that the secondary tissue for lead accumulation was not the digestive gland but the mantle. In view of high lead concentrations in the mantle, its general metabolic condition (including immune and antioxidant defense systems) as affected by the two metals was studied. The results indicated that activities of antioxidant enzymes (superoxide dismutase, SOD; Se-dependent glutathione peroxidase, Se-GPx) were altered by lead and copper in the similar way. However, the immune enzyme activities (acid phosphatase, AcPase; phenoloxidase, PO) were perturbed differently by two metals. Therefore, the mantle of P. fucata was predicted to participate in immune processes and accumulation or detoxification of lead besides shell formation. Our observations described here may also provide important clues to further understanding of the biomarker responses of bivalves.     

氨基酸及其受体在脑缺血中的作用及相关药物应用

脑缺血时,以Glu为代表的兴奋性氨基酸通过激活NMDA受体,引起Ca^2＋内流增多,最终导致神经细胞死亡,加重神经元损害。同时,GABA等抑制性氨基酸通过与Ca^2＋通道偶联,减少Ca^2＋内流,阻断Glu的兴奋毒效应。这些作用机制为兴奋性氨基酸受体拮抗剂、NOS抑制剂、Ca^2＋拮抗剂和自由基清除剂等作为脑缺血损伤防治药物的研究提供了理论基础。     

Compatibility of calcium chloride and calcium gluconate with sodium phosphate in a mixed TPN solution

The maximum concentrations of phosphate that will remain soluble in a parenteral nutrient solution containing various concentrations of calcium chloride or calcium gluconate were determined. Various concentrations of sodium phosphate were mixed with FreAmine II (McGaw Laboratories), and the resulting solutions were mixed with 50% dextrose solutions containing various concentrations of calcium chloride or calcium gluconate. The final solutions were sealed and stored at 30 degrees C for 24 hours and then were inspected visually for precipitate formation. It was found that higher equivalent concentrations of phosphate are attainable when calcium gluconate, instead of calcium chloride, is used as the calcium source. Factors found to influence the concentrations of calcium and phosphate that are compatible in amino acid solutions are the calcium salt used, temperature and duration of storage, dextrose concentration, amino acid composition, pH, and other additives.