Characterization of mammalian heart annexins with special reference to CaBP33 (annexin V)

Porcine heart was observed to express annexins V (CaBP33) and VI in large amounts, and annexins III and IV in much smaller amounts. Annexin V (CaBP33) in porcine heart was examined in detail by immunochemistry. Homogenization and further processing of heart in the presence of EGTA resulted in the recovery of annexin V (CaBP33) in the cytosolic fraction and in an EGTA-resistant, Triton X-100-soluble fraction from cardiac membranes. Including Ca2+ in the homogenization medium resulted in a significant decrease in the annexin V (CaBP33) content of the cytosolic fraction with concomitant increase in the content of this protein in myofibrils, mitochrondria, the sarcoplasmic reticulum and the sarcolemma. The amount of annexin V (CaBP33) in each of these subfractions depended on the free Ca2+ concentration in the homogenizing medium. At the lowest free Ca2+ concentration tested, 0.8 microM, only the sarcolemma appeared to contain bound annexin V (CaBP33). Membrane-bound annexins V (CaBP33) and VI partitioned in two fractions, one EGTA-resistant and Triton X-100-extractable, and one Triton X-100-resistant and EGTA-extractable. Altogether, these data suggest that annexins V and VI are involved in the regulation of membrane-related processes.     

Morphology of superficial postnatal cerebral cortex with special reference to synapses

Summary The ultrastructure of layers I and II of the motor cerebral cortex of rat brain has been studied at birth, 4, 7 and 14 days postnatal and in the adult.Compared with the adult, neonatal rat motor cortex exhibited a large extracellular space which decreases with increasing age. At all stages studied the neurons were seen to contain the organelles usually found in adult neurons. Growth cones were present in decreasing numbers up to 14 days old.Synapses were detectable at birth and there was an obvious increase in their number throughout the postnatal development. At the earliest stages studied there was a lack of specialization characteristic of the adult. Many synapses were either avesicular or relatively so and lacked the high degree of modification of adult pre- and postsynaptic membranes. By 7 days after birth many synapses existed which in all morphological respects resembled those of the adult, and by 14 days, the majority were of the adult type.These findings, particularly with reference to the postnatal development of synapses, have been discussed in relation to the known electrophysiological findings.The authors wish to express their thanks to Mr. R. Birchenough and Mr. J. Manston for their technical assistance.     

Blood-group distribution in india with special reference to bengal

Journal of Genetics - 1. Blood-group work for India is reviewed. Until 1934 nearly all samples were from mixed ethnological groups. 2. New data from lower Bengal show that the percentages ofA andB...     

Myoseptal architecture of sarcopterygian fishes and salamanders with special reference to Ambystoma mexicanum

During axial undulatory swimming in fishes and salamanders muscular forces are transmitted to the vertebral axis and to the tail. One of the major components of force transmission is the myoseptal system. The structure of this system is well known in actinopterygian fishes, but has never been addressed in sarcopterygian fishes or salamanders. In this study we describe the spatial arrangement and collagen fiber architecture of myosepta in Latimeria, two dipnoans, and three salamanders in order to gain insight into function and evolution of the myoseptal system in these groups. Salamander myosepta lack prominent cones, and consist of homogenously distributed collagen fibers of various orientations that never form distinct tendons. Fiber orientations are difficult to homologize with those of fish myosepta. The myosepta of Latimeria and dipnoans (Protopterus and Neoceratodus) illustrate that major changes in architecture occurred in the sarcopterygian clade (loss of horizontal septum), in the rhipidistian (dipnoans + tetrapods) clade (loss of epineural and epipleural tendon), and in tetrapods (loss of lateral tendons and myoseptal folding). When compared to fishes, the myosepta of wholly aquatic salamanders (Ambystoma mexicanum, Amphiuma tridactylum, Necturus maculosus) do not have the lateral tendons we suppose serve to transfer muscular forces posteriorly. We propose that alternative structures (most conspicuously present in Ambystoma) perform this function: posteriorly the relative amount of connective tissue increases considerably, and myosepta are disintegrated to horizontal lamellae of connective tissue. The structures thought to be involved in modulation of body stiffness in fishes during swimming are also absent in salamanders. Our data also have implications for the hypothesis that salamander hypaxial myosepta are designed to increase shortening amplification of the hypaxial muscle fibers. The posterior hypaxial myosepta of all three salamander species possess only mediolaterally directed collagen fibers, which would indeed amplify the shortening of the associated muscle.     

Studies on mammalian glucoamylases with special reference to monkey intestinal glucoamylase

1. Highly purified preparations of glucoamylase were obtained from liver, spleen and intestine of the monkey. The enrichment factor was lower for intestine (60-fold) compared with that of liver (1200-fold) and of spleen (2000-fold) but the final specific activities were of a similar magnitude. 2. The liver and spleen enzymes had maximum activity at pH4.8 whereas the intestinal enzyme showed an optimum at pH5.8. The K(m) values for both starch and maltose with spleen and liver enzymes were higher than for the intestinal enzyme. With the intestinal enzyme, the V(max.) values were higher for both starch and maltose than those of the spleen and liver enzymes. 3. Gel filtration on Sephadex G-200 under identical conditions revealed that liver and spleen enzymes emerge from the columns much later than the intestinal enzyme. 4. Evidence is presented that the glucoamylase activity of the intestinal mucosa is exhibited by the maltase II fraction. 5. Tris, pentaerythritol and turanose inhibited glucoamylase from all the three tissues, but turanose inhibited the spleen and liver enzymes to a higher degree than the intestinal enzyme.     

Morphology and immunocytochemistry of the turtle pituitary gland with special reference to the pars tuberalis

Summary Examination of pituitaries from young and adult turtles representing four families, reveals that in addition to the abundant juxtaneural pars tuberalis (JuxPT) found in this class of reptiles, there is generally a substantial amount of pars tuberalis (PT) tissue closely associated with the pars distalis (PD). The PT forms a cortical layer especially conspicuous around the anterior tip of the PD in some species (Trionyx, Kinosternon, Sternotherus), or it forms a thick dorsal layer of tissue irregularly extending onto the sides of the PD in others (Pseudemys, Chrysemys, Lepidochelys, Chelonia).Immunocytochemical studies using unlabelled second antibody and peroxidase-antiperoxidase reveal that in turtles of all ages, the PT tissue allied with the PD (the PTinterna) is composed primarily of cells containing glycoprotein hormones (FSH, LH and TSH), especially the gonadotropins. The juxPT, however, consists mainly of secretory cells unstained by the antisera tested and includes only a small number of gonadotropes and thyrotropes. Although usually widely distributed in the testudinate adenohypophysis, the great majority of gonadotropes and thyrotropes present in the hatchling are in the PTinterna. It is probable that a concentration of these cells in the PTinterna is widespread among vertebrates.In all turtles examined, lactotropes occur principally in the anterior and ventral part of the PD proper; somatotropes are posterior and dorsal. Corticotropes are concentrated as the lactotropes in the anterior PD, but some are also scattered throughout the posterior half of the gland. Lactotropes, corticotropes, and with a few exceptions, somatotropes, do not occur in PT tissue in the turtle.We are grateful to Drs. Harold Papkoff and J.C. Ramachandran of the Hormone Research Laboratory of the University of California in San Francisco for their generous gifts of several antisera and to Dr. Ludwig Sternberger for the peroxidase-antiperoxidase used in this study. Thanks are also given to Phyllis Thompson for assistance with the illustrations and to William Rainey, David Owen and John Cadle for specimens that they made available. Use of the facilities of the Electron Microscope Laboratory of the University of California at Berkeley is gratefully acknowledged, including use of the JEOL-JEM 100CX transmission electron microscope purchased under National Science Foundation Grant Number PCM-7821561. This work was supported by NSF grant PCM-7812470 to PL     

Morphology and ultrastructure ofOlisthodiscus luteus (Raphidophyceae) with special reference to the taxonomy

A flattened discoid flagellate collected from the Seto Inland Sea, Japan, has been examined by light and electron microscopy. This alga agrees well withClisthodiscus luteus Carter. It has two heterodynamic flagella emerging from a furrow on the upward side of the cell that contains six to 13 yellow-green parietal chloroplasts. It does not rotate but smoothly glide while swimming. The cell has a thin periplast lying between the plasmalemma and chloroplasts. Neither lipid bodies nor mucocysts are seen in the periplast. The pyrenoid matrix being free from thylakoids is penetrated by several cytoplasmic canals from various directions. There are no vesicles of periplastidal network in the narrow space between chloroplast envelope and chloroplast ER. The ultrastructural features ofO. luteus are unique, sharing certain characters with the raphidophycean algae but others withPseudopedinella pyriformis, a unique member of the Chrysophyceae.     

Immunohistochemical studies of the serotonergic supraependymal plexus in the mammalian ventricular system, with special reference to the characteristic reticular ramification

Distributional and morphological features, especially characteristics of the ramification of serotonin-containing supraependymal fibers (SEF), were studied in the ventricular systems of mammals (mouse, rat, guinea pig, rabbit, cat, dog, monkey) by means of a modified peroxidase antiperoxidase technique, using antiserotonin antiserum prepared in our laboratory. SEF were present in all ventricular systems, except on the third ventricle floor and in the choroid plexus. The density of SEF was higher in the smaller species. In the rat, light- and scanning electron microscopical SEF were almost completely abolished 1 week after intraventricular administration of 5,6-dihydroxytryptamine. Ramification of SEF was complicated; the SEF formed a true network with frequent anastomosing. In the ventricular system of rats rendered hydrocephalic by kaolin administration, the mode of axonal branching in the supraependymal plexus could best be analyzed by the scanning electron microscope because the meshes of the plexus were spread out.     

Cytoskeletal architecture of isolated mitotic spindle with special reference to microtubule-associated proteins and cytoplasmic dynein

We have studied cytoskeletal architectures of isolated mitotic apparatus from sea urchin eggs using quick-freeze, deep-etch electron microscopy. This method revealed the existence of an extensive three- dimensional network of straight and branching crossbridges between spindle microtubules. The surface of the spindle microtubules was almost entirely covered with hexagonally packed, small, round button- like structures which were very uniform in shape and size (approximately 8 nm in diameter), and these microtubule buttons frequently provided bases for crossbridges between adjacent microtubules. These structures were removed from the surface of microtubules by high salt (0.6 M NaCl) extraction. Microtubule- associated proteins (MAPs) and microtubules isolated from mitotic spindles which were mainly composed of a large amount of 75-kD protein and some high molecular mass (250 kD, 245 kD) proteins were polymerized in vitro and examined by quick-freeze, deep-etch electron microscopy. The surfaces of microtubules were entirely covered with the same hexagonally packed round buttons, the arrangement of which is intimately related to that of tubulin dimers. Short crossbridges and some longer crossbridges were also observed. High salt treatment (0.6 M NaCl) extracted both 75-kD protein and high molecular weight proteins and removed microtubule buttons and most of crossbridges from the surface of microtubules. Considering the relatively high amount of 75- kD protein among MAPs isolated from mitotic spindles, it is concluded that these microtubule buttons probably consist of 75-kD MAP and that some of the crossbridges in vivo could belong to MAPs. Another kind of granule, larger in size (11-26 nm in diameter), was also on occasion associated with the surface of microtubules of mitotic spindles. A fine sidearm sometimes connected the larger granule to adjacent microtubules. Localization of cytoplasmic dynein ATPase in the mitotic spindle was investigated by electron microscopic immunocytochemistry with a monoclonal antibody (D57) against sea urchin sperm flagellar 21S dynein and colloidal gold-labeled second antibody. Immunogold particles were closely associated with spindle microtubules. 76% of these were within 50 nm and 55% were within 20 nm from the surface of the microtubules. These gold particles were sporadically found on both polar and kinetochore microtubules of half-spindles at both metaphase and anaphase. They localized also on the microtubules between sister chromatids in late anaphase. These data indicate that cytoplasmic dynein is attached to the microtubules in sea urchin mitotic spindles.(ABSTRACT TRUNCATED AT 400 WORDS)     

Cell volume regulation in fish heart ventricles with special reference to taurine

A review of the cell volume regulation mechanism in heart ventricles of teleosts reveal that the mechanism is not only restricted to euryhaline species in a changing salinity regime but also is manifested in fresh-water fish. Taurine is the dominating amino acid and the main cellular osmo-effector in teleost hearts (accounting for 40-50% of the osmolality change). During hypo-osmotic regulation, cellular taurine is reduced by an efflux from the cells, whereas intracellular synthesis of taurine most probably accompanies hyper-osmotic regulation. Vertebrate hearts seem to have a high concentration of taurine and it may in general in vertebrate hearts also play a pivotal role in cellular osmoregulatory function.