两种切片方法检测肝糖原染色效果的比较

目的比较石蜡和冰冻两种不同切片用于检测牛蛙肝糖原的效果。方法采用石蜡和冰冻两种切片方法制作牛蛙肝脏切片,高碘酸希夫氏（periodicacid-Schiff＇s,PAS）染色法对肝糖原进行组织化学染色,光密度分析糖原含量。结果PAS染色显示肝糖原为紫红色或红色颗粒,冰冻切片中糖原颗粒明显大于石蜡切片,光密度分析显示,石蜡切片中糖原流失明显,与冰冻切片相比,糖原流失了约28％。结论两种切片均可用于糖原检测,冰冻切片制作环节较少、耗时短且染色过程中糖原不易流失。     

双歧杆菌发酵果蔬汁对小鼠抗疲劳作用的实验研究

目的检测发酵果蔬汁对小鼠的抗疲劳作用。方法将3种果蔬汁按一定比例加入双歧杆菌、保加利亚乳杆菌和嗜热链球菌,经发酵,分别以高中低3个剂量喂食小鼠30d后,进行小鼠负重游泳实验,检测肝糖原、乳酸和尿素氮等各项抗疲劳指标。结果3种果蔬汁均能显著延长小鼠负重游泳时间,提高小鼠肝糖原的储备量;降低小鼠游泳后血乳酸和尿素氮均值,增加血红蛋白含量及乳酸脱氢酶活性,减少血尿酸含量。且抗疲劳强度程度与型量声低有一定相差。结论3种发酵果蔬汁具有抗疲劳作用。     

中华蟾蜍糖原含量的季节变化

于2005年11月至2006年10月,用硫酸-蒽酮比色法和比重法测定了中华蟾蜍各月份的肝糖原和肌糖原含量及肝比重。结果显示:冬眠期间(11月至次年的2月),糖原含量逐月下降;2月份时出现临时回升,然后继续下降;4月份时肝糖原含量最低;5月份起,肝糖原含量逐渐上升;5月份时肌糖原含量为最低;6月份起,肌糖原含量逐渐上升。虽然在7-8月间出现过下降,两种糖原的含量在10月份时达到一年中的最高值。这些结果表明,蟾蜍糖原含量在一年中呈现显著的季节性波动。越冬前所储备糖原的一部分可能用于越冬期间维持高水平的血糖,一部分用于基础代谢。2月份时糖原含量的临时上升,可能是血液中作为防冻保护剂的葡萄糖运回肝脏和肌肉中再合成糖原的结果。7-8月间糖原含量降低可能与蟾蜍夏蛰有关。雌性5月至10月期间的肝糖原总体水平显著低于雄性,可能与依赖可得到葡萄糖的卵母细胞中的糖原合成有关。糖原含量的季节变化与蟾蜍的生活状态(越冬、繁殖等)有关,并与血糖含量有联动关系。     

饱食与饥饿对小鼠肝糖原含量影响的实验方法改良

把分别以定性或定量两种方式来比较饱食和饥饿对小鼠肝糖原含量影响的实验进行互补。采用三氯醋酸沉淀组织蛋白质，乙醇提取肝糖原后，以碘呈色法对其鉴定，再以葸酮法进行定量，最后提出对相关物质检测的实验设计要求。实验结果表明，饱食和饥饿状态对小鼠肝糖原含量影响在连续性的实验过程中变化都很明显。经过此番实验方法改良，使实验的整体性得到提高，对学生的综合能力训练得到强化。     

静脉注射用人免疫球蛋白细菌内毒素检测

探索静脉注射用人免疫球蛋白(IVIG)细菌内毒素含量的鲎试验检测方法。根据《中国药典》(2000版)细菌内毒素含量的检测方法进行,将待检品用NaOH调pH至中性,稀释至2.4倍可用标示灵敏度为0.25EU/m l的特异性鲎试剂进行细菌内毒素检测,结果与家兔法进行比较,并且在样品中加入定量内毒素0.6 EU/m l用两种方法进行对比试验。结果表明用细菌内毒素检测法(鲎试验法)检测静脉注射用人免疫球蛋白是可行的。     

糖耐康含药血清对高糖状态下大鼠肝细胞糖脂代谢的影响

摘要目的：研究糖耐康含药血清对高糖状态下大鼠肝细胞糖脂代谢的影响。方法：通过培养大鼠肝细胞,在高糖诱导肝细胞胰岛素抵抗状态下,给予高、中、低剂量的糖耐康含药血清共培养24h后,观察肝细胞增殖情况,用葡萄糖氧化酶法检测细胞的葡萄糖消耗量,培养基和肝细胞内TG含量,肝细胞糖原含量。结果：与正常组比较,高糖刺激下,肝细胞增殖显著受到抑制（P〈O．叭）、葡萄糖消耗量和糖原含量减少（P〈0．01）,TG含量增加（P〈O．01）;与高糖组比较,吡格列酮组与TNK各剂量上述情况有不用程度的改善。作用效果类似。结论：糖耐康含药血清具有改善高糖环境下肝脏糖脂代谢紊乱的作用,可能与增加肝细胞胰岛素敏感性改善IR有关。     

固相滤纸法测定鼠肝糖原合成酶的活性

探求简捷有效的测定鼠肝糖原合成酶活性的方法. 固相滤纸法测定该酶活性,并与文献报告的漂洗法进行比较,且用此方法观察糖尿病鼠肝糖原合成酶的活性. 两种方法所测得放射性计数无明显差异;糖尿病鼠肝糖原合成酶的活性明显降低. 固相滤纸法是一种较简捷,方便,不易污染的测定糖原合成酶的方法.     

一种高效经济的高质量植物RNA提取方法

建立了一种高效经济的植物RNA提取方法.在提取缓冲液中加入蔗糖、氯化钾和镁离子以提供对RNA分子的保护.破碎后的细胞于提取缓冲液中裂解后,用酚/氯仿变性并去除内源RNA酶和其他蛋白质,而后用pH 5.6 的NaAc沉淀RNA.用该方法提取RNA的得率较高,经电泳检测,RNA的完整性很好.RNA印迹分析和RT-PCR也都得到很好的结果.该方法还使实验成本大大降低.     

响应面法对黑果枸杞中花青素测定条件的优化

以黑果枸杞为原料,采用pH示差法,通过响应面法优化花青素含量的测定条件。通过单因素试验和Box-Behnken Design试验研究乙醇体积分数、pH 1.0缓冲液平衡时间、pH 4.5缓冲液平衡时间等3个变量对黑果枸杞中花青素响应值的影响程度。根据响应面的最优化分析,得出最佳条件是：用80%酸性乙醇溶液,超声萃取30min,取花青素提取液在pH 1.0和pH 4.5的缓冲液中各平衡80min,在最适波长处测定。通过试验验证,采用pH示差法,通过响应面法优化得到的黑果枸杞中花青素含量的测定条件,可靠准确、具有实用价值。     

金属螯合亲和层析纯化金属硫蛋白

将二价铜离子螯合在Chelating Sepharose Fast Flow凝胶上制成亲和层析柱,锌诱导兔肝和镉诱导小鼠肝经匀浆、乙醇处理后上柱,用pH4.0的醋酸盐缓冲液平衡,再用pH5.2不同浓度的醋酸盐缓冲液分别洗脱,可得两个金属硫蛋白(MT)洗脱峰,经确定先后为MT-2和MT-1.分离方法比传统的凝胶过滤-离子交换法简单、省时,适于实验室规模分离纯化.     

Affinity chromatography of amine oxidase from Aspergillus niger.

Omega-Aminohexyl-Sepharose 4B served as an excellent biospecific adsorbent for affinity chromatography of amine oxidase (monoamine:O2 oxidoreductase (deaminating), EC 1.4.3.4) from Aspergillus niger. The enzyme was completely adsorbed on this affinity resin when applied to a column in 0.1 M potassium phosphate buffer (pH 7.2). Although a small part of the enzyme was retained on the column through ionic interaction and eluted with 1.0 M potassium phosphate buffer (pH 7.2), most of the enzyme adsorbed was eluted with 0.5 M potassium phosphate buffer (pH 7.2) containing 10 mM butylamine. Essentially no retention of the enzyme on a column of epsilon-aminopentyl-Sepharose or delta-aminobutyl-Sepharose occurred under the same conditions, indicating that an appropriate length (more than approx. 12 A) of a hydrocarbon extension between the agarose matrix and the terminal amino group would be necessary for efficient adsorption of amine oxidase. The modification of the enzyme with 3-methyl-2-benzothiazolinone hydrazone (carbonyl inhibitor) or dithionite (reducing agent) resulted in loss of the ability to bind to omega-aminohexyl-Sepharose. It was also demonstrated that the affinity chromatography on omega-aminohexyl-Sepharose can be used as a powerful means of purifying this enzyme from crude extracts of Aspergillus niger. All of the three adsorbents were effective as a substrate in the amine oxidase reaction, but their substrate activities were as low as the corresponding free diamines.     

Effects of diabetes and glycogen on the distribution between soluble and particulate fractions of activities of enzymes involved in hepatic glycogen metabolism.

The large decreases in hepatic glycogen associated with alloxan diabetes in fed rats were accompanied by apparent decreases in total activities of glycogen synthase, phosphorylase, protein kinase and synthase phosphatase determined on 8000 × g supernatants of liver homogenates. Inclusion of 4% glycogen in the extraction buffer normalized total soluble activities of synthase in the diabetic. Whereas inclusion of 4% glycogen in the extraction buffer doubled total soluble phosphorylase, total activity remained lower in the diabetic than in the normal. Extraction and assay of soluble protein kinase were unaffected by added glycogen. When activities were determined on whole homogenates, total glycogen synthase activities were the same in normal and diabetic liver. Although the decreases in total activities of phosphorylase, kinase and phosphatase were less when determined on whole homogenates of livers from diabetic rats, the diabetes-related decreases in total activities remained significant. Therefore, it appears that while alloxan diabetes results in absolute decreases in total hepatic activities of phosphorylase, kinase and phosphatase, it may also result in redistribution of hepatic synthase and phosphorylase between soluble and particulate fractions, a phenomenon possibly related to tissue glycogen concentrations. Such a redistribution might be involved in the lack of control of hepatic glycogenesis observed in alloxan diabetic rats.     

Direct enzymatic procedure for the determination of liver glycogen

A method is proposed to measure glycogen content in liver homogenates without extraction and acid hydrolysis of tissue glycogen. Homogenates were treated with amyloglucosidase, which degrades glycogen to glucose, and the glucose was the determined enzymatically by the use of glucose oxidase and peroxidase. The method was shown to yield nearly complete (99%) recoveries of standard glycogen, while 5 hr of acid hydrolysis of standard glycogen were required to obtain comparable recoveries. When compared to an acid hydrolysis method for liver, amyloglucosidase degradation of rat liver glycogen and subsequent determination of glucose resulted in higher values for glycogen content. The amyloglucosidase, glucose oxidase: peroxidase method has the advantage of rapidity, whereas the traditional method consisting of extraction, precipitation, and acid hydrolysis is not only time consuming, but may also be subject to losses of glycogen in each step.     

Effect of buffer pH and peptide composition on the selectivity of peptide separations by capillary zone electrophoresis

A series of 10 synthetic peptides containing varying degrees of charge and hydrophobicity was used to study the effects of peptide composition and buffer pH on the selectivity of separations by capillary zone electrophoresis (CZE). A simple model is used to explain the effect of buffer pH on the separation. It was found that pH is an important parameter affecting the selectivity of CZE separations. Furthermore, it is shown that the selectivity of the separation is such that peptides differing in neutral amino acid composition can be resolved, and that even differences in a peptide's amino acid sequence can be detected. A protease digest of beta-lactoglobulin A is shown as a practical example of a separation of a complex peptide mixture.     

Carbon-13 and phosphorus-31 NMR study of hepatic metabolism in the perfused rat liver

Phosphorus-31 nuclear magnetic resonance (NMR) has been used to determine non-invasively absolute concentrations of phosphorylated metabolites in the perfused rat liver. It has been shown that the NMR method does detect cytoplasmic ATP and ADP (ATP:ADP ratio of 15 +/- 3) with no contribution from mitochondrial adenine nucleotides. The concentration of ATP was 7.2 +/- 0.3 mM in the cytosol of well-oxygenated liver, after two hours of perfusion with a Krebs-Ringer buffer. Other phosphorylated metabolites were detected, mainly inorganic phosphate (1.1 mumol/g liver wet weight), phosphorylcholine (1.0 mumol/g wet weight), glycerophosphorylethanolamine (0.34 mumol/g wet weight) and glycerophosphorylcholine (0.30 mumol/g wet weight). The intracellular pH measured from the position of the Pi resonance has a value of 7.2 +/- 0.1. It is likely that the detectable Pi originates from the cytosolic compartment since a pH value of 7.4-7.6 would be expected for the mitochondrial matrix. Natural abundance carbon-13 NMR has also been used to follow the glycogen breakdown in situ by measuring the intensity of the glycogen C-1 resonance in the perfused liver spectrum as a function of the perfusion time. The glycogenolytic process has been studied as a function of the glucose content of the perfusate. Rate of glycogenolysis from 2.7 to 0.16 muEq glycosyl units g wet weight-1 min-1 were found when glucose concentration in the perfusate was varied from 0 to 50 mM. The fate of 90% enriched [2-13C] acetate has been studied in the perfused rat liver by 13C-NMR in order to investigate the mitochondrial metabolism and the interrelations between cytosolic and mitochondrial pools of metabolites. Some compounds of the intermediary metabolism where found to be extensively labelled, e.g. glutamate, glutamine, acetoacetate and beta-hydroxybutyrate. Under our experimental conditions, labelling of glutamate reached a steady-state within 30 min after the onset of perfusion of 20 mM acetate. In addition, the observed incorporation of carbon-13 isotope into glutamine can be linked to the operation of the glutamate-glutamine antiporter and to the high activity of the cytosolic glutamate synthetase. The finding of both active glutaminase and glutamine synthetase activity in the same liver cells is an evidence of the existence of an active glutamine-glutamate futile cycle.     

Coating efficiency of a 1 -acid glycoprotein in competitive enzyme immunosorbent assays with antigen immobilized on the solid phase

Coating efficiency of rat and human serum a 1 -acid glycoprotein (a 1 -AGP) was investigated for competitive enzyme immunosorbent assays with antigen immobilized on the solid phase by using different pHs and buffers. Blocking materials and pH of coating buffer had a marked influence on the amount of a 1 -AGP that binds to plate. Usually, carbonate buffer is used at pH 9.6 or 9.0, but phosphate buffered saline (PBS) at pH 7.2 can be used for an effective coating. At pH 7.2, coating of a 1 -AGP in Tris buffered saline was five - tenfold as effective as in PBS and phosphate buffer. Blocking of uncoated surface with casein was ten - twenty times as effective as with fetal bovine serum albumin for coating of a 1 -AGP.     

Antigen retrieval trial for post-embedding immunoelectron microscopy by heating with several unmasking solutions.

A novel antigen retrieval procedure was carried out in the post-embedding immunogold electron microscopy method to improve the stainability of the samples. This was done by weakly fixing cultured Helicobacter pylori (ATCC43504) and embedding in Lowicryl K4M. Before staining with the anti-H. pylori antibody, the ultrathin sections were mounted on a nickel grid and heated at 121C for 15 min, 99C for 40 min, and 65C for 24 hr in distilled water, 0.1 M phosphate buffer (pH 7.4), 0.01 M EDTA (pH 7.2), 0.05 M Tris buffer (pH 10.0), 0.8 M urea (pH 7.2), 0.01 M citric acid (pH 6.0), or a commercially available target unmasking fluid (S1699; pH 6.0). Antigen retrieval in the Tris buffer solution generally showed better stainability than the classical post-embedding method without any antigen retrieval. At 65C for 24 hr, better stainability of the ultrasections was observed for each of the solutions used except for the phosphate buffer compared to the control. We suggest that the antigen retrieval method should be applied for routine use even by in post-embedding immunogold electron microscopy.     

Analytical and micropreparative capillary electrophoresis of the peptides from calcitonin.

The capillary electrophoresis (CE) of peptide fragments from the tryptic digest of salmon calcitonin and elcatonin has been carried out in H2O- and D2O-based buffer solutions. Analysis in heavy water was found to be superior to that in H2O especially at a pH or pD of 7.93. From a single CE run on elcatonin digest we were also able to harvest three pure cleavage peptides in sufficient quantity to determine each amino acid residue by protein sequencing. The order of elution from CE agreed with that predicted on the basis of net charge calculated for each peptide.     

克雷伯杆菌产1,3-丙二醇关键酶甘油脱水酶的酶活分析方法研究

有氧条件下,建立了克雷伯杆菌破碎方法及其生产1,3-丙二醇代谢途径中关键酶甘油脱水酶的酶活测定方法。甘油脱水酶酶活测定时在超声时间25min,功率为300w的条件下最适破碎频率为破碎时间1s,停息时间4s;甘油脱水酶酶活测定所用磷酸盐缓冲液的最适浓度为0.045mol/L,最适pH值7.2。甘油脱水酶酶活测定反应的最佳温度为37℃,甘油脱水酶酶活测定反应液的最佳吸收波长为290nm。     

Rat albumin inhibits the formation of apoceruloplasmin during storage

Purified rat ceruloplasmin is extraordinarily unstable in storage at –70 °C. In a 20 mM phosphate buffer, pH 7.0, the ferroxidase and amine oxidase of ceruloplasmin are over 90% inactivated within two weeks. Holoceruloplasmin stored for three months in a 20 mM barbital buffer (or acetate buffer), pH 7.0 (or pH 5.5) was transformed into an apo-protein and amine (o-dianisidine) oxidase of ceruloplasmin was inactivated by 50–55%. The patterns of ferroxidase activity loss were similar to those of amine oxidase activity loss. On the contrary, when holoceruloplasmin was mixed with rat serum albumin, transformation into apoceruloplasmin was significantly prevented in a 20 mM barbital buffer, pH 7.0 (or 20 mM acetate buffer, pH 5.5). Consequently, ferroxidase and amine oxidase activities of ceruloplasmin were not inactivated and the immunochemical reactivity was not changed. These results can be applied for laboratorial and clinical purposes.