关于家蝇线粒体氧化磷酸化和亚显微结构的研究

本文报道有关家蝇胸肌线粒体氧化磷酸化作用和亚显微结构的实验和观察结果。试验证明,家蝇胸肌线粒体在离体条件下对`α``-甘油磷酸有很高的氧化和磷酸化活力,而对三羧酸循环各底物及其他氧化底物的氧化和磷酸化速率则极为微弱。胸肌匀浆以及线粒体与上清液的重组合试验结果和单独用分离的线粒体试验结果基本相同,从而有利于说明造成上述现象的原因可能不是由于线粒体在制备过程中受到损伤,而是家蝇胸肌线粒体膜对这些底物存在着特殊的透性屏障。在以`α``-甘油磷酸为氧化底物时,线粒体在下述保温条件下可获得很高的氧化速率和P/O比值:线粒体浓度较稀(2毫升反应液中含1—2毫克线粒体蛋白);保温时间较短(10—20分钟之内)以及外加一定量的牛血浆清蛋白(0.2%)。DDT对线粒体的氧化和磷酸化反应均表现强烈的抑制作用,但在正常家蝇和抗性家蝇中则表现出一定的差别。在离体试验的条件下,DDT(0.1m`M``)对正常家蝇线粒体的氧化抑制40%,对磷酸化抑制60.9%,而抗性家蝇则分别为23.4%和42.7%;在反应系统中外加牛血浆清蛋白时,DDT对正常家蝇线粒体的氧化抑制71.1%,磷酸化抑制94.8%,而抗性家蝇则分别为59.7%和87.1%。在DDT(5%)处理整体家蝇时,正常家蝇线粒体的氧化被抑制21%,磷酸化被抑制33%,而抗性家蝇则分别为11.5%和26.9%;在反应系统中外加牛血浆清蛋白时,DDT处理后的正常家蝇线粒体的氧化被抑制7.0%,磷酸化被抑制6.1%,而在抗性家蝇中则不表现任何抑制作用。电子显微镜的观察也证明,DDT处理后,正常家蝇线粒体的结构表现出明显的解体现象,但抗性家蝇线粒体仅在个别情况下表现为少数线粒体内膜的破坏,从而说明抗性家蝇线粒体在形态结构和生化功能两方面都表现出对DDT的一定程度的抗性。对本文的有关试验结果进行了讨论。     

夜行昆虫复眼光感受器的显微和亚显微结构的研究

粘虫蛾的复眼由许多小眼组成。每个小眼有8个小网膜细胞。根据它们形态学上的特征和视小杆的位置,可区分为1个顶细胞、6个主细胞和1个基细胞。 1.顶细胞视小杆在视杆顶端,组织切片上被橘黄-G染色,胞核在暗适应时不发生位移,胞质内有大量核糖体。 2.主细胞视小杆集合成束,均匀排列,占据视杆中段,切片上被光绿染色,胞核在暗适应时向晶锥方向移动,胞质内见不到核糖体。 3.基细胞视小杆在视杆下段轴心内,胞核紧靠基底膜,核与视小杆中间的胞体变细成丝状,内有许多色素小体,胞质内有核糖体。顶细胞与主细胞的胞体横切面上,可见到相邻的细胞膜有微孔相通,微孔附近有胞桥小体。对这三类感光细胞的功能及其在夜间视觉中的作用进行了探讨。     

鲤鱼和鲫鱼脾脏显微结构和亚显微结构的研究

鲤鱼和鲫鱼的脾脏中都没有小梁,其红髓和白髓是混合的。脾脏中都有椭圆体,其末端向脾髓开放。脾髓的纤维网眼中缺乏血管壁,椭圆体毛细血管中的血液可直接流入脾髓网状结缔组织的腔隙中。腹腔注射墨汁的鲫鱼,2小时后即可在椭圆体的巨噬细胞中看到碳粒的积累,可见脾脏的过滤作用主要在椭圆体中进行。在注射墨汁的鲫鱼脾脏中,黑色素巨噬细胞中心比未经注射鱼的脾脏明显,且数量增多,它和哺乳动物淋巴结和脾脏中的生发中心结构和功能都不相同。       

低温下转昆虫抗冻蛋白基因烟草的亚显微结构变化

分析在-1℃温度中处理1、2和3d的转昆虫抗冻蛋白基因MpAFP149烟草和野生型烟草亚细胞显微结构变化的结果表明,转基因烟草和野生型烟草的超微结构有差异,尤其是细胞膜、叶绿体和线粒体的膜。转基因烟草细胞器的膜结构伤害程度明显低于野生型烟草,这提示低温条件下转基因烟草中的抗冻蛋白可能有保护细胞膜和细胞器膜结构的作用,由此降低了低温的伤害。     

磁场对防风体细胞胚发生发育和亚显微结构的影响

近年来,关于防风的离体培养国内学者相继进行了研究,余绍华等（１９８５）用幼叶诱导愈伤组织分化出根芽;慈忠玲和陈惠民（１９９５,１９９６）通过悬浮培养诱导体细胞胚发生及再生植株,对单细胞至球形胚形成的各阶段作了显微及超微结构观察,并对其培养过程中的染色体变异进行了分析;盛世红和陈惠民（１９９０）用原生质体培养获得了再生植株。但目前还未见磁场对防风胚状体发生和发育影响方面的报告。关于生物磁学在植物组织培养中的应用,赵成章（１９８０）研究了磁场对水稻花粉愈伤组织诱导和分化的影响;王曼丝和李鸣镝（１９９…     

花粉亚显微结构研究技术

做过花粉超薄切片的人们都知道,要想得到充整满意的连续切片和清晰的花粉电镜照片是比较困难的。造成闲难的原因主要有:(1)花药壁(尤其是禾本科植物的花药壁)外表皮上有一层较厚的蜡质,在固定、脱水及包埋过程中溶剂较难渗入。(2)花粉囊中往往有空气,花药漂浮在固定液上不下沉。(3)较成熟的小孢予的外壁厚而坚硬,其内壁也较厚。花粉外壁的主要成份是能耐酸、碱和射线的孢粉素。外壁不仅是溶剂渗透的重要障碍,而且在切片时     

细胞的亚显微结构

一.前言自从电子显微镜发明并改进和提高了它的解象力,设计出了较满意的固定、包埋和切片方法,有可能切出薄到200埃厚度的组织切片以来,近十几年来在生物学和医学中已进行了许多方面的研究工作,并且得到了很显著的成绩。目前电子显微镜的解象力已达到10埃左右,与可见光显微镜比较(以下简称为光学显微镜,其解象力为0.2微米),提高了约二百倍。因此,在细胞构造方面观察到了许多以前未能见到的微细结构,并且提出了许多代表这些结构的新名词。     

线粒体的发生和起源

线粒体起源是研究细胞起源的一个重要课题。本文综述了关于线粒体发生和起源的研究现状,介绍了两种不同的假说。正如作者所说:“自然科学中的思维总是在一定的哲学思想指导下进行的,总是受着科学工作者的世界观支配的。对于各种各样的假说,我们应当用辩证唯物主义的观点进行分析,分清是非,批判唯心主义和形而上学的种种表现,才能使科学研究循着正确的道路前进。”这个意见值得大家注意。自然科学工作者应当深入学习马克思主义、列宁主义、毛泽东思想,树立无产阶级世界观,自觉地运用辩证唯物主义指导科学研究,遵照毛主席关于“有比较才能鉴别。有鉴别,有斗争,才能发展”和“百家争鸣”的教导,对种种科学假说进行比较和鉴别,在科学实践的基础上,提出自己的见解,将这一基础理论研究推向前进。     

DEGENERATIVE CHANGES IN THE MITOCHONDRIA OF FLIGHT MUSCLE FROM AGING BLOWFLIES

Mitochondria from flight muscle of aging blowflies, Phormia regina, were examined morphologically and biochemically with the electron microscope. An age-dependent degeneration of the mitochondria that is characterized, in part, by the reorganization of the inner membrane into myelin-like whorls has been found. The concentric rings increase in size and number, eventually replacing the normal cristal conformation. Glycogen rosettes are frequently seen in the center of the whorl and may represent the intrusion into the mitochondria of the glycogen in the cytoplasmic matrix of the muscle. The degenerating mitochondria are not associated with lysosomal activity, as indicated by the absence of acid phosphatase. An intense acid phosphatase activity is noted, however, in the dyad, comprising elements of the T system and sarcoplasmic reticulurn. Cytochrome oxidase is active in the ultrastructurally intact portion of the mitochondrion but activity is not evident in that part of the mitochondrion that has undergone morphological change. Thus, the ultrastructural degradation of the mitochondria is correlated with a decrease in biochemical function. This suggests a correspondence between a decrease in the bioenergetic capacity of the flight muscle and a decline in the ability of the aged insect to fly.     

STUDIES ON THE STRUCTURE OF MUSCLE : III. PHASE CONTRAST AND ELECTRON MICROSCOPY OF DIPTERAN FLIGHT MUSCLE

1. The flight muscles of blowflies are easily dispersed in appropriate media to form suspensions of myofibrils which are highly suitable for phase contrast observation of the band changes associated with ATP-induced contraction. 2. Fresh myofibrils show a simple band pattern in which the A substance is uniformly distributed throughout the sarcomere, while the pattern characteristic of glycerinated material is identical with that generally regarded as typical of relaxed vertebrate myofibrils (A, I, H, Z, and M bands present). 3. Unrestrained myofibrils of both fresh and glycerinated muscle shorten by not more than about 20 per cent on exposure to ATP. In both cases the A substance migrates during contraction and accumulates in dense bands in the Z region, while material also accumulates in the M region. It is proposed that these dense contraction bands be designated the C_z, and C_m bands respectively. In restrained myofibrils, the I band does not disappear, but the C_z and C_m bands still appear in the presence of ATP. 4. The birefringence of the myofibrils decreases somewhat during contraction, but the shift of A substance does not result in an increase of birefringence in the C_z and C_m bands. It seems therefore that the A substance, if it is oriented parallel with the fibre axis in the relaxed myofibril, must exist in a coiled or folded configuration in the C hands of contracted myofibrils. 5. The fine structure of the flight muscle has been determined from electron microscopic examination of ultrathin sections. The myofibrils are of roughly hexagonal cross-section and consist of a regular single hexagonal array of compound myofilaments the cores of which extend continuously throughout all bands of the sarcomere in all states of contraction or relaxation so far investigated. 6. Each myofilament is joined laterally with its six nearest neighbours by thin filamentous bridges which repeat at regular intervals along the fibre axis and are present in the A, I, and Z, but not in the H or M bands. When stained with PTA, the myofilaments display a compound structure. In the A band, a lightly staining medullary region about 40 A in diameter is surrounded by a densely staining cortex, the over-all diameter of the myofilament being about 120 A. This thick cortex is absent in the I and H bands, but a thinner cortex is often visible. 7. It is suggested that the basic structure is a longitudinally continuous framework of F actin filaments, which are linked periodically by the lateral bridges (possibly tropomyosin). The A substance is free under certain conditions to migrate to the Z bands to form the C_z bands. The material forming the C_m bands possibly represents another component of the A substance. The results do not clearly indicate whether myosin is confined to the A bands or distributed throughout the sarcomere.     

ISOLATION, ULTRASTRUCTURE, AND BIOCHEMICAL CHARACTERIZATION OF GLYCOGEN IN INSECT FLIGHT MUSCLE

Glycogen from flight muscle of the blowfly, Phormia regina, has been characterized ultrastructurally and biochemically. In situ, glycogen is in the form of rosettes, which vary in size with diameters of up to 0.1 µ. Sedimentation analysis of pure glycogen, isolated by mild buffer extraction, reveals a polydisperse molecular weight spectrum, with larger particles having molecular weights of 100 million. Treatment of native glycogen with alkali, under conditions usual for the extraction of the polysaccharide from tissues, results in a 5- to 10-fold reduction in molecular weight, as well as a chemical alteration of the molecule. Flight muscle phosphorylase has a lower affinity for native than for alkali-treated glycogen. The maximum velocity of the enzyme is also lower with native substrate. The apparent K_m for inorganic phosphate is higher with native glycogen as cosubstrate. These kinetic differences with native and partially degraded glycogen demonstrate the importance of using the natural substrate in studies of biochemical control mechanisms.     

STUDIES ON THE BIOCHEMISTRY OF MITOCHONDRIA AND CELL MORPHOLOGY IN THE NEONATAL SWINE HEPATOCYTE

Mitochondrial preparations isolated from neonatal swine hepatocytes show a marked increase in oxidative and concomitant phosphorylative capacity between birth and 2 days postpartum. There are no changes in the coupling parameters (respiratory control ratio and adenosine diphosphate/O ratio) with age. Changes in sedimentation properties in a sucrose gradient suggest qualitative changes in the mitochondria. Some of the lipid measurements (increased phospholipid) might be interpreted as supportive of this suggestion, although most could also be regarded as indicative of quantitative changes (increased number of mitochondria). Electron microscopy of isolated mitochondria and of the hepatocyte demonstrated an increased number of mitochondria but no change in shape, size, or structure as the pig developed. An increase in a number of cytoplasmic components (Golgi apparatus and endoplasmic reticulum) and a decrease in glycogen were also observed. The functional changes in mitochondria seem to occur within a short period of time (6–12 hr postpartum).     

粘虫Leucania separata Walker蛾飞翔肌线粒体的氧化磷酸化作用和呼吸控制

线粒体是细胞呼吸代谢和能量代谢的中心,有关它的结构和机能是近代生物化学研究中极活跃的领域之一。氧化磷酸化作用,即电子在呼吸链传递过程中偶联有高能磷酸键(腺苷三磷酸ATP)的合成,是线粒体的主要机能,也是研究生物能代谢的重要方面。 氧化磷酸化作用已经在几种昆虫飞翔肌线粒体中被研究过(Sacktor,1961;Slater,1960;Лю Шу-сэнь,1962)。早期研究结果证明,昆虫线粒体与高等动物肝细胞线粒体的区别是前者P/O比值较低,α-甘油磷酸的氧化速率大大高于三羧酸循环各基质的氧化速     

STUDIES ON THE CONTENT AND ORGANIZATION OF THE RESPIRATORY ENZYMES OF MITOCHONDRIA

(1) The mathematical calculations relating spectrophotometric data with the data of Allard et al. (4, 5) on mitochondrial counts, is presented. Such a calculation indicates that an "average mitochondrion" from rat liver would contain about 17,000 molecules of each cytochrome pigment. (2) Hematocrit determinations relating respiratory pigment content for mitochondria isolated from a variety of tissues have been presented, showing a fivefold variability depending upon the source of the mitochondria. (3) Speculations on the organization of the respiratory enzymes associated with the membrane structure of the mitochondria are discussed.     

厚颌鲂含肉率及生化成分的分析

研究了长江上游特有鱼类厚颌鲂的含肉率及其肌肉生化成分和能值。结果表明 :厚颌鲂的含肉率为72 72 % ;其肌肉生化成分 (鲜重百分比 ) :水分含量为 79 2 6%、蛋白质 16 82 %、脂肪 2 10 %、灰分 1 0 8%、无氮浸出物 0 73 %、比能值 4 93KJ/g及E/P2 9 3 3KJ/g。肌肉生化成分含量与体长变化无明显关系。经单因素方差分析 5— 6月份样品与 10月份样品在脂肪和无氮浸出物含量上有显著差异 (P <0 0 5)。肌肉中含有 17种氨基酸 ,总量为69 54% (干重百分比 ) ;9种人体必需氨基酸总量是 3 3 0 7% ,占氨基酸总量比例为 47 55% ;必需氨基酸指数 (EAAI)是 61 75。缬氨酸和异亮氨酸为限制性氨基酸 ;四种鲜味氨基酸含量为 5 85% (鲜重百分比 )。     

BIOCHEMICAL EFFECTS OF VICTORIN ON OAT TISSUES AND MITOCHONDRIA

Victorin, the pathotoxin produced by the plant pathogenic fungus Helminthosporium victoriae, causes changes in respiration and permeability which are typical of diseased plant tissues. To provide information on the site and mode of action of this toxin, the effects of victorin on mitochondria were studied and the nature and quantities of materials released from victorin-treated tissues were determined. Victorin added to isolated mitochondria had no effect on release of electrolytes or on oxidative-phosphorylative capacity. Hence the high respiratory rate found in victorin-treated tissues does not appear to be the result of a direct effect of the toxin on the respiratory centers. With mitochondria extracted from tissue pretreated with victorin, electrolyte release was unaffected but oxygen uptake was slightly higher and phosphate esterification considerably lower than controls. Thus the toxin produces indirect effects on mitochondrial activity, but the relation of these effects to tissue respiration remains undetermined. Victorin-treated tissue lost much larger quantities of certain organic and inorganic materials than control tissue with the most striking difference in the amount of potassium released.     

MITOCHONDRIA IN CARDIAC MUSCLE CELLS OF THE CANARY AND SOME OTHER BIRDS

The fine structure of mitochondria from the ventricular myocardium of canaries, sparrows, zebra finches, quail, and geese has been studied. The first three of these birds have very fast heart rates, the quail being intermediate, and the goose has a relatively slow rate. The canary heart has a unique form of mitochondrion containing large, parallel arrays of zigzag or angled cristae. Other cristae, continuous with the zigzag ones and also occupying large parts of the mitochondrial volume, are named retiform because of the hexagonal network which they form, sometimes in a single plane and sometimes three dimensional. These two types of cristae appear to be interconnectible. It is possible that there is a direct functional significance in these peculiar forms, but, in any case, the relative constancy of dimensions in these arrays is probably related to specific properties of the molecules of which the cristal membrane is composed. It is also demonstrated that this membrane is composed in part of approximately 30-A particles which are believed to be protein molecules. This unusual mitochondrial morphology is not seen either in the other fast bird hearts or in the slower ones, so that there is neither a simple correlation with heart rate nor probably with the separate parts of the cardiac cycle. Although none of the other four hearts shows more than an occasional angled crista, there does seem to be a rather gross correlation between heart rate and mitochondrial size and complexity of crista structure, but no correlation with presence or absence of zigzag forms. The cristae of quail heart mitochondria are disposed in unusually large close-packed whorls.