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1.
Magnesium-activated adenosine triphosphatase activity in the giant mitochondria (sarcosomes) of the flight muscle of aging male houseflies decreases concomitantly with failure in flight as reflected in the loss of wings during the second week of adult life. Preceding the loss of wings, however, there is a rapid decline in the activity of an alpha-glycerophosphate dehydrogenase which is located in the extramitochondrial fraction and is dependent on nicotinamide adenine dinucleotide. 相似文献
2.
Milan D Jeon JT Looft C Amarger V Robic A Thelander M Rogel-Gaillard C Paul S Iannuccelli N Rask L Ronne H Lundström K Reinsch N Gellin J Kalm E Roy PL Chardon P Andersson L 《Science (New York, N.Y.)》2000,288(5469):1248-1251
A high proportion of purebred Hampshire pigs carries the dominant RN- mutation, which causes high glycogen content in skeletal muscle. The mutation has beneficial effects on meat content but detrimental effects on processing yield. Here, it is shown that the mutation is a nonconservative substitution (R200Q) in the PRKAG3 gene, which encodes a muscle-specific isoform of the regulatory gamma subunit of adenosine monophosphate-activated protein kinase (AMPK). Loss-of-function mutations in the homologous gene in yeast (SNF4) cause defects in glucose metabolism, including glycogen storage. Further analysis of the PRKAG3 signaling pathway may provide insights into muscle physiology as well as the pathogenesis of noninsulin-dependent diabetes mellitus in humans, a metabolic disorder associated with impaired glycogen synthesis. 相似文献
3.
Increased phosphorylation of myosin light chain kinase after an increase in cyclic AMP in intact smooth muscle 总被引：6，自引：0，他引：6
P de Lanerolle M Nishikawa D A Yost R S Adelstein 《Science (New York, N.Y.)》1984,223(4643):1415-1417
The role of cyclic adenosine monophosphate-mediated phosphorylation of myosin light chain kinase in relaxing smooth muscle was examined. The kinase was immunoprecipitated from tissue extracts and the phosphate content was determined. The addition of forskolin to resting or methacholine-contracted muscles resulted in an increase in myosin light chain kinase phosphorylation of myosin light chain kinase is one of the reactions in the process by which cyclic adenosine monophosphate causes relaxation of smooth muscle. 相似文献
4.
The rate of pyruvate oxidation by mitochondria from blowfly flight muscle decreased in the presence of tris (hydroxymethyl) aminomethane (Tris). An increase in the rate of mitochondrial swelling was concomitant with the loss of pyruvate oxidation. These changes were prevented by bovine serum albumin, adenosine triphosphate, and magnesium ions, factors required for mitochondrial contraction. Proline, but not glutamate or malate, restored the rate of pyruvate oxidation to original values. These findings suggest that mitochondrial swelling leads to leakage of intramitochondrial intermediates of the Krebs cycle, accounting for the decrease in the rate of pyruvate oxidation. Exogenous proline penetrates the mitochondrial membrane and is rapidly oxidized, via glutamate, forming intramitochondrial precursors of oxaloacetate. Malate and glutamate were ineffective because of the selective permeability of the mitochondrial membrane. 相似文献
5.
Thermoregulation in endothermic insects 总被引：2，自引：0，他引：2
B Heinrich 《Science (New York, N.Y.)》1974,185(153):747-756
On the basis of body weight, most flying insects have higher rates of metabolism, and hence heat production, than other animals. However, rapid rates of cooling because of small body size in most cases precludes appreciable endothermy. The body temperature of small flies in flight is probably close to ambient temperature, and that of flying butterflies and locusts is 5 degrees to 10 degrees C above ambient temperature. Many moths and bumblebees are insulated with scales and hair, and their metabolism during flight can cause the temperature of the flight muscles to increase 20 degrees to 30 degrees C above ambient temperature. Curiously, those insects which (because of size, insulation) retain the most heat in the thorax during flight, also require the highest muscle temperature in order to maintain sufficient power output to continue flight. The minimum muscle temperature for flight varies widely between different species, while the maximum temperature varies over the relatively narrow range of 40 degrees to 45 degrees C. As a consequence, those insects that necessarily generate high muscle temperatures during flight must maintain their thoracic temperature within a relatively narrow range during flight. Active heat loss from the thorax to the abdomen prevents overheating of the flight motor and allows some large moths to be active over a wide range of ambient temperatures. Bumblebees similarly transfer heat from the flight musculature into the abdomen while incubating their brood by abdominal contact. Many of the larger insects would remain grounded if they did not actively increase the temperature of their flight muscles prior to flight. Male tettigoniid grasshoppers elevate their thoracic temperature prior to singing. In addition, some of the social Hymenoptera activate the "flight" muscles specifically to produce heat not only prior to flight but also during nest temperature regulation. During this "shivering" the "flight" muscles are often activated in patterns different from those during flight. The muscles contract primarily against each other rather than on the wings. However, the rate of heat production during shivering and flight is primarily a function of the action potential frequency rather than of the patterns of activation. Thermoregulation is a key factor in the energetics of foraging of some of the flower-visiting insects. The higher their muscle temperature the more flowers they can visit per unit time. When food supplies are ample, bees may invest relatively large amounts of energy for thermoregulation. While shivering to maintain high body temperatures during the short intervals they are perched on flowers (as well as while in the nest), bumblebees often expend energy at rates similar to the rates of energy expenditure in flight. Unlike vertebrates, which usually regulate their body temperature at specific set points, the body temperature of insects is labile. It often appears to be maintained near the lower temperature at which the muscles are able to perform the function at hand. The insects' thermal adaptations may not differ as much from those of vertebrates as previously supposed when size, anatomy, and energy requirements are taken into account. 相似文献
6.
In the membrane of the flight muscle cells of developing Drosophila a large calcium-sensitive potassium current, IKc, was found. It was present before the development of voltage-activated potassium channels and seems to be the first potassium current to develop in the membrane. Also present in these early cells were large numbers of occult (hidden) calcium channels, which remained inactive until the end of pupal development. These inactive calcium channels could be made to function by injecting adenosine triphosphate or ethyleneglycol tetraacetic acid into the early cells. IKc has kinetic properties resembling the later developing voltage-sensitive current IKv, and is distinct from the fast, transient calcium-dependent outward current IAc, which appears much later in development. IAc closely resembles the voltage-sensitive current IAv, also present in these cells. Thus, both of the voltage-sensitive potassium channel types, IAv and IKv, have similar calcium-sensitive counterparts, IAc and IKc, that are present in the same cells. 相似文献
7.
8.
Tucker VA 《Science (New York, N.Y.)》1966,154(3745):150-151
Budgerygahs (Melopsittacus undulatus) flew with a minimum oxygen consumption of 38 milliliters per gramhour at each of three speeds between 19 and 33 kilometers per hour in a recirculating wind tunnel. An oxygen debt accumulated in the first minute of flight and was repaid in the minute following cessation of flight. Frequency of wingbeat was independent of flight speed. The data suggest that flying budgerygahs have a higher cardiac output per kilogram of body weight than mammals and that flight muscle of the budgerygah is among the most metabolically active tissues known. 相似文献
9.
Muscle contraction and free energy transduction in biological systems 总被引：52，自引：0，他引：52
Muscle contraction occurs when the actin and myosin filaments in muscle are driven past each other by a cyclic interaction of adenosine triphosphate (ATP) and actin with cross-bridges that extend from myosin. Current biochemical studies suggest that, during each adenosine triphosphatase cycle, the myosin cross-bridge alternates between two main conformations, which differ markedly in their strength of binding to actin and in their overall structure. Binding of ATP to the cross-bridge induces the weak-binding conformation, whereas inorganic phosphate release returns the cross-bridge to the strong-binding conformation. This cross-bridge cycle is similar to the kinetic cycle that drives active transport and illustrates the general principles of free energy transduction by adenosine triphosphatase systems. 相似文献
10.
Transport of energy in muscle: the phosphorylcreatine shuttle 总被引：27，自引：0，他引：27
In order to explain the insulin-like effect of exercise, it was proposed in 1951 that contracting muscle fibers liberate creatine, which acts to produce an acceptor effect--later called respiratory control--on the muscle mitochondria. The development of this notion paralleled the controversy between biochemists and physiologists over the delivery of energy for muscle contraction. With the demonstration of functional compartmentation of creatine kinase on the mitochondrion, it became clear that the actual form of energy transport in the muscle fiber is phosphorylcreatine. The finding of an isoenzyme of creatine phosphokinase attached to the M-line region of the myofibril revealed the peripheral receptor for the mitochondrially generated phosphorylcreatine. This established a molecular basis for a phosphorylcreatine-creatine shuttle for energy transport in heart and skeletal muscle and provided an explanation for the inability to demonstrate experimentally a direct relation between muscle activity and the concentrations of adenosine triphosphate and adenosine diphosphate. 相似文献
11.
[目的]研究成年大鼠快肌内侧腓肠肌与慢肌比目鱼肌内各型肌纤维的分布及构成差异。[方法]应用RT-PCR方法分析4型肌纤维的肌球蛋白重链异构体基因表达差异,并以肌动球蛋白腺苷三磷酸酶组织化学染色分析4型肌纤维构成比例。[结果]通过RT-PCR扩增所得的条带,在内侧腓肠肌内MHCⅠ、MHCⅡx、MHCⅡa、MHCⅡb基因表达均有分布,而在比目鱼肌中未发现有Ⅱb型基因表达。4型或3型肌纤维均呈交错式镶嵌型分布。[结论]大鼠内侧腓肠肌中ⅡA型肌纤维占很大比例,而在比目鱼肌中I型肌纤维最多,其中缺少ⅡB型肌纤维。 相似文献
12.
320羽Avian雏鸡按饲养试验要求分为4组(每组4个重复,每个重复20羽),设对照组(饲喂玉米豆粕型基础日粮),试验组在基础日粮中分别添加酵母核酸0.05%、0.1%和0.2%,42日龄时,进行屠宰试验, 每组16羽(每个重复4羽), 共64羽, 采集胸肌肌肉样品,测定有关肉质的指标.结果表明,酵母核酸显著提高了胸肌粗蛋白含量3.21%～3.80%(P<0.05),粗脂肪含量则呈下降趋势(P>0.05),干物质、灰分各组之间无明显影响;添加酵母核酸显著提高肌肉肌苷酸和腺苷酸含量,分别为22.16%～35.03%(P<0.05)、41.44%～55.86%(P<0.05), 次黄嘌呤含量各组之间无明显的影响;具有提高肌红蛋白含量的趋势(P>0.05);添加酵母核酸显著提高了胸肌中甘氨酸、酪氨酸、亮氨酸、苯丙氨酸、赖氨酸含量和必需氨基酸总量、氨基酸总量,其中,试验组1甘氨酸提高了44.97%(P<0.05),试验组2亮氨酸提高了17.67%(P<0.05),试验组3酪氨酸、苯丙氨酸、赖氨酸、必需氨基酸总量、氨基酸总量分别提高了37.34%(P<0.05)、29.24%(P<0.05)、17.39% (P<0.05)、14.44%(P<0.05)、10.94%(P<0.05).添加酵母核酸对肉鸡胸肌中常量和微量元素含量无明显的影响. 相似文献
13.
《农业科学学报》2019,18(5):982-991
The root quality of sweet potato cultivated during the summer season is poor in northern China;thus,this study was conducted to determine whether root quality could be improved through mulching with plastic film(MPF).The effect of MPF on root starch and its composition,the activity of starch synthesis enzymes,and other quality-related parameters were investigated in two purple flesh sweet potato cultivars,Jishu 18 and Ayamurasaki(Aya).The results indicated that root dry matter,anthocyanin content,adenosine triphosphate(ATP),and starch content were higher in both cultivars under the MPF treatment than those under the control treatment.The root adenosine diphosphate glucose pyrophosphorylase/uridine diphosphate glucose pyrophosphorylase(ADPGPPase/UDPGPPase)activity and adenosine triphosphatease(ATPase)activity were increased using MPF.However,under the MPF treatment,the amylose content,soluble sugar content,and granule-bound synthase(GBSS)activity increased in Jishu 18 but decreased in Aya,and the amylopectin content,protein content,and soluble starch synthase(SSS)activity decreased in Jishu 18 but increased in Aya.Therefore,MPF seems benifit to improve the quality of sweet potato,but the effects of this treatment condition may be dependent on the cultivar. 相似文献
14.
Normalization of depressed heart function in rats by ribose 总被引：3，自引：0，他引：3
H G Zimmer 《Science (New York, N.Y.)》1983,220(4592):81-82
Severe constriction of the abdominal aorta and simultaneous injection of isoproterenol in rats induced depression in heart function and reductions in cardiac adenosine triphosphate and total adenine nucleotides. When ribose was continuously infused for 24 hours, biosynthesis of cardiac adenine nucleotides was stimulated to such an extent that the reductions in adenosine triphosphate and total adenine nucleotides were prevented and left ventricular hemodynamic parameters were normal. These results support the hypothesis that adenosine triphosphate is primarily responsible for depression in myocardial contractility and that ribose is cardioprotective through its pronounced effects on adenine nucleotide metabolism in heart muscle. 相似文献
15.
Some noctuid winter moths fly at near 0 degrees C by maintaining an elevated(30 degrees to 35 degrees C) thoracic muscle temperature. Geometrid winter moths sustain themselves in free flight at subzero muscle temperatures. However, the temperature characteristics of citrate synthase and pyruvate kinase from both of these different kinds of moths and from a sphinx moth that flies with a muscles temperature of 40 degrees C are nearly identical. Furthermore, mass-specific rates of energy expenditure of both kinds of winter moths are also similar at given thoracic temperature (near 0 degrees C). The geometrids that are able to fly with a thoracic temperature near 0 degrees C do so largely because of unusually low wing-loading, which permits a low energetic cost of flight. 相似文献
16.
Cyclic adenosine monophosphate: potassium-dependent action on vascular smooth muscle membrane potential 总被引：5，自引：0，他引：5
Dibutyryl cyclic adenosine monophosphate and theophylline hyperpolarize smooth muscle of rabbit main pulmonary artery in low concentrations of potassium (1 millimole per liter) but do not have a significant effect on the membrane potential in the presence of high concentrations of potassium (10 millimoles per liter). The dependence of the hyperpolarizing effect on a low external concentration of potassium is similar to that observed with isoproterenol. Prior treatment with theophylline potentiated the hyperpolarizing action of isoproterenol. These findings are compatible with the assumption that potassium-dependent, beta-adrenergic hyperpolarization is mediated by cyclic adenosine monophosphate. 相似文献
17.
The relationship between the (Na(+) and K(+))-activated adenosine triphosphatase enzyme system implicated in sodium-transport by cell membranes and the calcium-activated adenosine triphosphatase, which is generally associated with calcium uptake, was examined in microsomes from skeletal muscle. Whereas sodium and potassium did not modify the relatively low adenosine triphosphatase activity seen in the absence of calcium, a pattern similar to that of the sodium-transport enzyme system was seen afer the addition of CaCl(2). The calcium-activated adenosine triphosphatase was stimulated equally by sodium or potassium alone, but both the rate and extent of calcium uptake were enhanced more by potassium than by sodium at concentrations below 0.12 mole per liter. In the absence of either of these ions addition of calcium failed to activate adenosine triphosphatase although significant amounts of calcium were taken up by the microsomes. 相似文献
18.
选取健康1日龄雏鸡200只,随机分为2组,低硒组(饲料硒含量为0.033 mg·kg-1)和对照组(饲料硒含量为0.15 mg·kg-1),分别于0、15、25、35、45、55日龄取胸肌、翅肌、腿肌组织,高效液相色谱法检测DNA总甲基化水平,实时荧光定量PCR方法检测DNA甲基转移酶1(DNMT1)、DNA甲基转移酶3A(DNMT3A)、DNA甲基转移酶3B(DNMT3B)mRNA表达水平.结果表明,DNA总甲基化水平整体呈降低趋势,低硒组与对照组相比DNMT1、DNMT3A mRNA表达量先增加后减少,DNMT3B各组均低于正常组并且随日龄增加组内呈降低趋势.硒缺乏可导致鸡肌肉组织DNA甲基化水平降低. 相似文献
19.
为了探究不同运营管理模式、不同水库鳙(Aristichthys nobilis)肌肉的生化和物理特性差异。采用常规生化分析法和组织学特性分析法,对上海三大饮用水源地青草沙、陈行、金泽水库2龄鳙肌肉的脂肪、蛋白、氨基酸、脂肪酸等生化特性和质构等物理特性进行了分析。结果显示：鳙肌肉的粗蛋白含量在18.11%~18.63%之间、粗灰分1.27%~1.34%之间,二者在三个水库之间均无显著差异(P>0.05);青草沙水库鳙肌肉的pH值(6.45%)和水分(80.69%)含量显著高于陈行(6.27%、78.43%)、金泽水库(6.24%、79.28%)(P<0.05);金泽水库鳙的粗脂肪含量(0.76%)显著高于青草沙(0.29%)、陈行水库(0.28%)(P<0.05);三个水库鳙肌肉检出的氨基酸和脂肪酸均为17种,金泽水库(10.49%)鳙肌肉的总SFA含量显著高于青草沙 (8.46%)、陈行水库(9.30%)(P<0.05);质构指标除黏附性没有显著差异(P>0.05),其余指标如硬度、弹性、凝聚性等均有显著差异(P<0.05);金泽水库鳙的肌细胞数量、长径显著低于青草沙、陈行水库(P<0.05)。研究表明,不同水库环境对鳙肌肉的蛋白、灰分含量影响差异不显著,对脂肪含量、肌纤维组织学特性影响差异显著,三个水库鳙肌肉均为优质蛋白源,陈行水库鳙肌肉的营养价值更高。 相似文献
20.
不同鸡种肌肉常量化学成分的比较研究 总被引：2，自引：0，他引：2
对5个鸡种不同性别及不同部位肌肉(胸肌与腿肌)的6项常量化学成分:水分、粗蛋白质、粗脂肪、粗灰分、钙、磷含量进行比较分析,结果表明:①这6项常量化学成分在不同鸡种、不同性别、不同部位肌肉之间有所不同,均具有极显著(P<0.01)或显著(P<0.05)差异。②胸肌的水分含量(73.69%~75.90%)高于腿肌(69.48%~72.96%)。南海麻黄鸡的胸肌水分含量(♂74.31%、♀75.90%)显著高于黄鸡(N系)(♂73.76%、♀73.81%)(P<0.05),而腿肌则是黄鸡(K系)显著高于黄鸡(N系)(P<0.05)。③胸肌粗蛋白质(19.77%~21.34%)高于腿肌(15.31%~17.54%)。黄鸡(N系)的胸肌粗蛋白质含量极显著高于黄鸡(K系)(P<0.01),腿肌是黄鸡(N系)显著高于黄鸡(K系)(P<0.05)。④胸肌粗脂肪含量(1.63%~2.67%)低于腿肌(7.42%~10.32%)。黄鸡(N系)的胸肌含量最高,江西鸡含量最低,但差异不显著(P>0.05),腿肌是黄鸡(N系)显著高于江西鸡(P<0.05)。⑤胸肌粗灰分含量(0.93%~1.31%)略高于腿肌(0.81%~1.12%)。黄鸡(N系)的胸肌含量极显著高于黄鸡(K系)(P<0.01),黄鸡(K系)腿肌含量极显著高于南海麻黄鸡(P<0.01)。⑥5个鸡种的钙、磷含量(0.02%~0.04%、0.07%~0.19%)都较低。江西鸡的胸肌、腿肌钙含量显著高于黄鸡(N系)(P<0.05),黄鸡(N系)的胸肌磷含量极显著高于黄鸡(K系)(P<0.01),而腿肌磷含量则是黄鸡(N系)极显著高于南海麻黄鸡(P<0.01)。 相似文献