量热法研究线粒体代谢的热力学和动力学行为

线粒体是细胞中极为重要的细胞器，是产生细胞所必需的“富能”物质ATP的重要场所，为细胞活动提供所需化学能．在生命体能量代谢过程中除一部分能量用于合成ATP外，其余则以热的形式释出．用精密热量计测出线粒体代谢过程中的热量输出对了解线粒体的功能和代谢机制具有十分重要的意义．用微量热法研究线粒体体外代谢已有一些报导［‘，’］．本工作用精密热量计和差式扫描量热仪侧定了水稻线粒体体外代谢热谱和DSC曲线，计算了水稻线粒体活性增长速率常数，比较了不同保藏时间的水稻线粒体体外代谢的差异，并初步探讨了水稻线粒体在变…     

微量热法表征邻香草醛氨基葡萄糖Schiff碱锌配合物的抗菌活性

用微量热法测定了大肠杆菌（细菌）及其在Ｚｎ－ｏ－ＶＧ（ｏ－ＶＧ：邻香草醛氨基葡萄糖Ｓｃｈｉｆｆ碱）作用下不同温度下的热谱；计算了它的生长速率常数ｋ、传找时间Ｇ、抑制率Ｉ、总产热量Ｑ、单个细菌的平均产热Ｑ０的单位时间平均每个细菌的产热量＾－量Ｑ０；建立了细菌生长代谢各种参量之间的函数关系，探讨了在不同温度和药物作用下细菌的生长代谢；发现可用ｔｇ、ｔｒ和ｔ表征细菌的生长代谢和药物的抗菌活性。     

线粒体体外代谢热动力学研究

线粒体是细胞重要的细胞器之一，有细胞的“能源工厂”之称．因为线粒体内有许多酶，是特殊的酶催化氧化反应的场所山；所有动、植物细胞的线粒体都能通过各种营养物的氧化而产生“富能”物质ATP．采用一定的技术可将线粒体从细胞中分离出来，分离出来的线粒体中的酶系统还有一定的活性，而且线粒体内也有一定的营养物质，这样酶系统就能利用这些营养物进行代谢，从而释放出一定的能量．我们用微量热法对两种鱼肝脏线粒体进行了测量，发现线粒体代谢过程分四个阶段：停滞期、活性恢复期、稳定期、活性衰减期．在活性恢复期和活性衰减期，…     

环境气氛对微量热安瓿法测定细菌生长速率常数的干扰

采用微量热安瓿法测定细菌生长时,发现细菌的代谢产热曲线在第一指数生长期内出现了停留法没有报导过的显著分阶段现象,且在不同的阶段生长速率常数有很大差异,对药物抗菌性能的评估造成极大干扰.为了寻找此现象的可能原因,以具有代表性的兼性细菌大肠杆菌为例,设计了微量热安瓿法实验,考察了不同环境气氛下大肠杆菌的生长代谢产热;并模拟了停留法条件下细菌的生长环境,通过安瓿法测定了大肠杆菌的生长代谢产热,重新解析了这些条件下细菌的生长速率常数.结果表明环境气氛是造成此现象的主要可能因素,并为在不同环境气氛下采用微量热安瓿法准确评估细菌的生长速率提供了一个可参考的标准.     

乌头类双酯型生物碱对嗜热四膜虫生长的毒性效应微量热学研究

建立灵敏表征乌头类双酯型生物碱(DDA)对嗜热四膜虫生长代谢影响的评价方法.采用微量热法,在不同给药条件下,以表达功率-时间曲线(热谱曲线)的特征参数生长速率常数(k)、半数抑制浓度(IC50)、最大输出功率(Pmax)及达峰时间(tp)和总产热量(Qt)为指标,对嗜热四膜虫生长代谢程度进行客观地量化评价.结果表明,随着3种DDA浓度的增加,达峰时间tp延长,生长速率常数k、最大输出功率Pmax等随之降低,且生长速率常数k与相应的浓度间呈现良好的线性关系:r乌头碱=0.9910(IC50=207.7μg·mL-1);r新乌头碱=0.9923(IC50=412.5μg·mL-1);r次乌头碱=0.9977(IC50=1497μg·mL-1).同时由半抑制浓度IC50得到3种DDA毒性的大小顺序:乌头碱新乌头碱次乌头碱.初步构效关系研究表明,在化合物C(3)上引入羟基(OH)以及N原子上引入乙基(CH2CH3)均可明显增加双酯型生物碱对嗜热四膜虫的毒性作用.     

微量热法测定细菌的临界生长温度

应用微量热学的方法,我们已能成功地测得细菌生长过程的热谱,这种热谱包含着有关细菌生长代谢过程的丰富信息,例如对热谱曲线的指数生长段进行解析,可得出细菌生长的速率常数、激活能和有关的热力学参数。故采用微量热法测定细菌在不同培养温度下的生长速率常数,利用计算机拟合出相应k(速率常数)和T(培养温度)的线性关系式后,若把生长速率为零的温度定义为临界生长温度时,就可以根据由上述实验所得的k～T线性关系式求得细菌的临界生长温度。本工作仍采用微量热法对福氏志贺氏菌(S. flexneri)和大肠埃希氏菌(E. coli)进行实验测定。按文献的方法求出它们在不同温度下的生长速率常数;对于大肠埃希氏菌还用几种不同的培养基分别进行实验测定。     

微量量热法研究黄连中小檗碱类生物碱对金黄色葡萄球菌生长代谢的影响

采用微量量热法研究中药黄连中具有抑菌作用的3种小檗碱类生物碱成分对金黄色葡萄球菌生长代谢的影响．在不同给药条件下,以表达功率．时间曲线（热谱曲线）的特征参数生长速率常数k、半数抑菌浓度（IC50）、最大输出功率（Pmax）及达峰时间（tp）和总产热量（Qt）为指标,对3种小檗碱类生物碱成分抑制金黄色葡萄球菌生长代谢程度进行客观地量化评价．结果表明,k、Pmax和Qt均随3种小檗碱类生物碱成分浓度的增加而相应的减小;tp随3种小檗碱类生物碱成分浓度的增加而相应的延长;其IC50分别为小檗碱101．4μg／mL、巴马汀241．0μg／mL和药根碱792．3μg／mL,即抑菌活性大小顺序为小檗碱〉巴马汀〉药根碱．初步构效关系研究提示,位于苯环的C2、C3上的亚甲二氧基或甲氧基较羟基更有助于提高其抑菌活性．     

左金丸及类方HPLC指纹图谱与生物热活性的“谱-效”关系研究

HPLC法建立左金丸及类方水提液的特征指纹图谱, 计算各特征峰的相对峰面积, 并采用中药色谱指纹图谱相似度评价系统A版(2004 A)计算类方间的相似度; 微量热法测定大肠杆菌在左金丸及类方水提液作用下的热谱曲线, 得到相应的热动力学参数, 如生长速率常数k, 最大产热功率Pm, 最高峰的出峰时间tm和总产热量Qt等, 并对这些热动力学参数进行主成份分析. 典型相关分析法对左金丸及类方HPLC 指纹图谱中特征峰的相对峰面积与其类方作用下大肠杆菌生长代谢的主要热动力学参数相关联, 研究“谱-效”相关性. 结果表明, HPLC 指纹图谱与生物热活性存在很好的相关性, 类方中吴茱萸次碱、盐酸巴马汀、盐酸小檗碱的含量差异是导致其生物热活性不同的主要原因.     

微量量热法研究增溶性辅料吐温80对红细胞生理活性的影响

建立灵敏、专属性较好地表征增溶性辅料吐温80对红细胞生理活性影响的评价方法.采用微量量热法以生命体能量代谢特征参数衰亡速率常数(k)、最大热功率(Pmax)、总发热量(Q)、衰亡时间(t)为评价指标,考察增溶性辅料吐温80作用下红细胞的能量动态变化过程.结果表明,随着吐温80浓度(C)的增大,红细胞生长代谢特征参数总发热量(Q)降低、最大热功率(Pmax)增强、衰亡时间(t)减小、衰亡速率常数(k)减小,Q,k与ln C间量效关系良好(相关系数r>0.95);不同厂家吐温80作用于红细胞的总发热量(Q)存在显著性差异(P<0.05).与肉眼观察法、分光光度法、细胞计数等常规方法比较,微量量热法较能实时在线、全息地监测增溶性辅料对红细胞生理活性的动态过程,尤其是对亚致死效应细胞测定的分辨能力.该法可用于增溶性辅料吐温80质量标准的生物测定,亦为红细胞能量代谢等相关研究提供了实验参考.     

微量量热法研究増溶性辅料吐温80对红细胞生理活性的影响

建立灵敏、专属性较好地表征増溶性辅料吐温80对红细胞生理活性影响的评价方法.采用微量量热法以生命体能量代谢特征参数衰亡速率常数(k)、最大热功率(Pmax)、总发热量(Q)、衰亡时间(t)为评价指标,考察增溶性辅料吐温80作用下红细胞的能量动态变化过程.结果表明,随着吐温80浓度(C)的增大,红细胞生长代谢特征参数总发热量(Q)降低、最大热功率(Pmax)增强、衰亡时间(t)减小、衰亡速率常数(k)减小,Q,k与lnC间量效关系良好(相关系数r0.95);不同厂家吐温80作用于红细胞的总发热量(Q)存在显著性差异(P0.05).与肉眼观察法、分光光度法、细胞计数等常规方法比较,微量量热法较能实时在线、全息地监测增溶性辅料对红细胞生理活性的动态过程,尤其是对亚致死效应细胞测定的分辨能力.该法可用于增溶性辅料吐温80质量标准的生物测定,亦为红细胞能量代谢等相关研究提供了实验参考.     

Effects of bioaccumulation of PCBs on biodiversity and distribution of fish in two creeks in east Tennessee (USA)

The Oak Ridge Reservation, established in Tennessee during World War II as a research, development and process facilities support for the Manhattan Project, released large quantities of organic, inorganic and radionuclear contaminants into the environment. Their effects are particularly evident in aquatic ecosystems, as chemical concentrations in water, and as a disease in biodiversity and species richness. East Fork Poplar Creek and its tributary, Bear Creek flow inside the Reservation and have highly degraded natural habitats, unsatisfactory water quality and impoverished biota. PCB concentrations exceed recommended criteria for aquatic life safety and appear as a primary cause of environment degradation and reduced species richness. An uptake model, FGETS (Food and Gill Exchange of Toxic Substances) was used to analyse fish biodiversity and distribution in the two streams in relation to bioaccumulation of PCB congeners 1254 and 1260. Bioaccumulation of the two polychlorinated biphenyls was estimated in four different species of fish common in Tennessee rivers and streams: Catostomus commersoni, Lepomis macrochirus, Cyprinus carpio and Micropterus salmoides to integrate the available set of data and to evaluate the entity of human impact on these escosystems.     

铜在鱼体中的积累规律研究

采用实验室模拟对鱼所生存的人工水环境中投Cu的方式,通过鱼对Cu的吸收富集研究了鱼体中Cu的积累规律及其Cu对部分鱼内脏的毒性影响。揭示不同质量浓度下,单一重金属离子在鲫鱼体内积累的动态变化规律以及铜对鲫鱼属于剧毒重金属。结果表明,在较低的质量浓度下Cu在鲫鱼各组织器官中的积累量随质量浓度的增加而增加、随时间的延长而增加,达到一定时间后积累趋于平衡;在高质量浓度环境下Cu在鲫鱼各组织器官中的积累量有时随时间的延长反而有所下降,但针对不同组织来说其积累能力由大到小顺序一般为:内脏,鱼鳃,肌肉。采用主要的分析方法是微波溶样消解法和火焰原子吸收分光光度法。     

Long-term UVB Irradiation Affects the Immune Functions of Carp (Cyprinus carpio) and Rainbow Trout (Oncorhynchus mykiss)

The effects of long-term, low-dose ultraviolet B (UVB) radiation on immune functions of two fish species representing different taxonomic groups, carp ( Cyprinus carpio ) and rainbow trout ( Oncorhynchus mykiss ), were assessed in this study. The fish were exposed to 7, 20 or 60 mJ cm⁻² UVB three times per week, for 6 weeks. In carp, UVB exposure affected the respiratory burst activity of blood and head kidney phagocytes, differential blood leukocyte counts and blood chemistry. Phytohemagglutinin (PHA)-stimulated in vitro proliferation responses of blood and head kidney lymphocytes, however, remained unchanged. Rainbow trout tolerated the irradiations with fewer alterations, but significant changes were detected in blood chemistry and hematocrits of the irradiated fish. These results indicate that long-term exposure to low doses of UVB induces immunomodulation in fish, and that there are species-specific differences in sensitivity to irradiation.     

Calorimetry and potentiometry of chemical oscillations in Briggs-Rauscher reactions with simultaneous measurements of the produced oxygen volume

The Briggs-Rauscher reaction is known as a nonlinear and non-equilibrium chemical oscillation reaction. The reaction solution is composed of malonic acid as organic substrate, hydrogen peroxide and iodate in sulphuric acid as oxidizing agent, and manganese (II) as metal catalyst. The calorimetric behaviour, in terms of the total heat Q and the heat evolving rate q for each chemical oscillation, was followed with the use of a heat exchange calorimeter of the batch type assembled by the authors. Simultaneously, the concentration of iodide ions produced as the intermediate species was measured as the potential difference E by the common potentiometric cell incorporated in the calorimeter and the released oxygen volume G was also observed by a simple flowmeter. The starting point of the peak on the curve of q against time t coincided with that in the curve of E against t. The switching concentration of iodide between radical and nonradical paths was calculated from literature values of rate constants. The heat evolving period of Q coincided with the period in the radical path. The curve of Q against t also coincided with that of G against t. The total volume of released oxygen was larger than that calculated from the stoichiometric reaction formula.     

微量热法研究氰化物对鲤鱼肝线粒体代谢的影响

A microcalorimetric technique based on the metabolic heat-output was explored to evaluate the inhibition of cyanide on the mitochondrial metabolism of aquatic animal, Cyprinus carpio. The power-time curves could be divided into four parts： lag phase, active recovery phase, stationary phase, and decline phase, and the corresponding thermokinetic parameters were obtained. The maximum heat production rate Pmax decreased in a linear manner with the increase of concentration of cyanide, however, such mitochondria of aquatic animal were still metabolized actively even under the action of high concentration of cyanide. All the observations suggested that the mitochondria of this aquatic animal should exhibit considerable ability of cyanide-resistant respiration.     

Microcalorimetric studies on the mitochondria metabolism of Cyprinus Carpio val and its parents

The metabolic thermogenic curves of liver mitochondria isolated from the livers of Cyprinus Carpio vol and its parents were determined at 28°C by using an LKB‐2277 Bioactivity Monitor. The results indicated that their thermogenic curves are different The total heat output and total time of the metabolism of the liver mitochondria of the hybrid F₁ (Cyprinus Carpio val) are more than those of its parents, and its maximum heat power is between that of the female parent and male parent. The relationship between their metabolic thermogenic curves and character of mitochondrial metabolism, and thermokinetics and the heterosis were analyzed and discussed. The character of the mitochondrial thermogenic curves reflected the physiologic character of heterosis. The microcalorimetric method proved to be a probable and sensitive tool for the assessment of heterosis.     

Electron exchange between alpha-Keggin tungstoaluminates and a well-defined cluster-anion probe for studies in electron transfer

Fully oxidized alpha-AlIIIW12O40(5-) (1ox), and one-electron-reduced alpha-AlIIIW12O40(6-) (1red), are well-behaved (stable and free of ion pairing) over a wide range of pH and ionic-strength values at room temperature in water. Having established this, 27Al NMR spectroscopy is used to measure rates of electron exchange between 1ox (27Al NMR: 72.2 ppm relative to Al(H2O)63+; nu(1/2) = 0.77 Hz) and 1red (74.1 ppm; nu(1/2) = 0.76 Hz). Bimolecular rate constants, k, are obtained from line broadening in 27Al NMR signals as ionic strength, mu, is increased by addition of NaCl at the slow-exchange limit of the NMR time scale. The dependence of k on is plotted using the extended Debye-Hückel equation: log k = log k0 + 2alphaz1z2mu(1/2)/(1 + betarnu(1/2)), where z1 and z2 are the charges of 1ox and 1red, alpha and beta are constants, and r, the distance of closest contact, is fixed at 1.12 nm, the crystallographic diameter of a Keggin anion. Although not derived for highly charged ions, this equation gives a straight line (R2 = 0.996), whose slope gives a charge product, z1z2, of 29 +/- 2, statistically identical to the theoretical value of 30. Extrapolation to mu = 0 gives a rate constant k11 of (6.5 +/- 1.5) x 10(-3) M(-1) s(-1), more than 7 orders of magnitude smaller than the rate constant [(1.1 +/- 0.2) x 10(5) M(-1) s(-1)] determined by 31P NMR for self-exchange between P(V)W12O40(3-) and its one-electron-reduced form, P(V)W12O40(4-). Sutin's semiclassical model reveals that this dramatic difference arises from the large negative charges of 1ox and 1red. These results, including independent verification of k11, recommend 1red as a well-behaved electron donor for investigating outer-sphere electron transfer to molecules or nanostructures in water, while addressing a larger issue, the prediction of collision rates between uniformly charged nanospheres, for which 1ox and 1red provide a working model.     

Effects of short- and long-term ultraviolet B irradiation on the immune system of the common carp (Cyprinus carpio)

Carp (Cyprinus carpio) were repeatedly exposed to 0, 60, 120 and 240 mJ/cm2 ultraviolet B (UVB) radiation three times in 1 week (short-term exposure) or 12 times in 4 weeks (long-term exposure). The effect of UVB on the functioning of the carp immune system was studied on day 2 after the final irradiation. After short-term UVB exposure, the whole-blood respiratory burst and cytotoxic activity were markedly enhanced, with parallel responses in both the number of circulating granulocytes and in the plasma cortisol concentration of the fish. These changes were not detectable after long-term exposure. The respiratory burst by head kidney granulocytes was suppressed dose dependently after both exposures, but cytotoxic activity was not affected. Exposure to UVB also modulated lymphocyte functions: nonstimulated and PHA-stimulated proliferation of head kidney lymphocytes in vitro was enhanced by both short-term and long-term exposure. LPS-stimulated proliferation was not affected by exposure nor was the number of immunoglobulin-secreting cells in the head kidney. In long-term exposure, the highest dose reduced the level of plasma IgM. This study indicates that UVB irradiation induces immunomodulation in the blood and head kidney of the carp and that the effects of short- and long-term exposure differ from each other. The results emphasize the potentially harmful impact of increased solar UVB radiation on fish immune functions.     

微量热法研究亚砷酸钠对鲫鱼肝脏线粒体的影响

Metabolic thermogenic curves of mitochondria isolated from liver tissue of Carassius auratus and the effect of different concentration of NaAsO2 on it were investigated by TAM air isothermal microcalorimeter, ampoule method, at 28.00 ℃. From the thermogenic curves, activity recovery rate constants k, the maximum heat production rate （Pmax） and the total heat produced （Q） were obtained. The values of k and Pmax decline gradually with the increase of the concentration of NaAsO2, and both of the values of Pmax and k are highly correlated to the concentration of NaAsO2. When concentration of NaAsO2 reached 16.0 μg/mL, the maximum heat production rate dropped to 70.8% of the control group, and the corresponding percentage of k was 71.4% of the control group. This experimental result indicates that the addition of NaAsO2 has restrained the metabolic activities of mitochondria in vitro.