Incorporation of phospholipids in Ehrlich ascites tumor cells

Summary Ehrlich ascites tumor cells (EATC) were incubated with unilamellar vesicles (UV) or multilamellar vesicles (MV). UV and MV were incorporated differently into EATC. The increase in³²P-phospholipid in EATC in the presence of UV was 12% in 300 min. Absorption of phospholipid from MV could account for only 3%. About 50% of the UV incorporation of³²P was by endocytosis and/or fusion.This work was supported by a grant from the Consejo Nacional de Investigaciones Científicas y Técnicas, Argentina. J. L. Corchs is an investigator from the Consejo Nacional de Investigaciones Científicas y Técnicas.     

Morphometric study of the aortic body types I cell

Summary The subclavian glomus (aortic body) of New Zealand white rabbits was examined ultrastructurally using stereological morphometric analysis. The Type I cells of the glomus possess numerous electron-opaque vesicles which occupy approximately 12% of the cytoplasmic volume of the cells. The amine-containing vesicles comprise a heterogeneous population of vesicles with a mean caliper diameter of 113.5 nm. Differences in vesicle diameters may indicate the storage of different biogenic amines, different secretion or maturation states between glomera and/or additional physiological functions for the glomera.Supported by NIH Grant 5-TO1-GM793 and The University of Texas.     

Morphometric study of the aortic body type I cell.

The subclavian glomus (aortic body) of New Zealand white rabbits was examined ultrastructurally using stereological morphometric analysis. The Type I cells of the glomus possess numerous electron-opaque vesicles which occupy approximately 12% of the cytoplasmic volume of the cells. The amine-containing vesicles comprise a heterogeneous population of vesicles with a mean caliper diameter of 113.5 nm. Differences in vesicle diameters may indicate the storage of different biogenic amines, different secretion or maturation states between glomera and/or additional physiological functions for the glomera.     

Gap junctional intercellular communication of cultured rat liver parenchymal cells is stabilized by epithelial cells and their isolated plasma membranes

The gap junctional intercellular communication (GJIC) determined by measuring dye coupling with Lucifer yellow, decreased within 3 d from 66% to 28% in monocultures of rat liver parenchymal cells. Coculturing of the parenchymal cells with a nonparenchymal epithelial cell line from rat liver resulted in increased and stabilized intercellular communication (83% after 3 d). The presence of isolated plasma membrane vesicles of the nonparenchymal epithelial cells also stabilized the intercellular communication between the liver parenchymal cells (70% after 3 d). When liver parenchymal cells were cocultured with a rat liver fibroblast cell line the gap junctional communication between the parenchymal cells was not stabilized (43% after 3 d), and isolated plasma membrane vesicles of the fibroblast were also unable to support the GJIC in parenchymal cells (35% after 3 d). It is concluded that plasma membrane constituents of the nonparenchymal epithelial cells were responsible for the stabilization of the GJIC between parenchymal cells. A heterotypic gap junctional communication between parenchymal and nonparenchymal cells was not observed.     

Chlorpromazine causes vesicle population changes in the monoaminergic synapse of the rat caudate nucleus.

The population of monoaminergic synaptic vesicles in the rat caudate nucleus remained unchanged or slightly decreased 3 h after chlorpromazine (CP) administration, and clearly increased after 24 h. The diameter of synaptic vesicles became smaller when the vesicles increased. These findings suggest that CP causes presynaptic blocking in part of its actions and leads to a condition in which neural transmission is inactive. In the control animals, population of the vesicles tended to fluctuate following the circadian rhythm.     

Molecular machinery mediating vesicle budding,docking and fusion

A general machinery buds and fuses transport vesicles which connect intracellular compartments with each other and allow communication with the extracellular environment. Cytoplasmic coat proteins deform membranes to bud vesicles and interact directly or indirectly with cargo molecules. Compartment-specific SNAREs (SNAP receptors) on vesicles and target membranes dock vesicles and provide a scaffolding for the general fusion machinery to initiate lipid bilayer fusion.     

Evolution of the thermotropic properties of large unilamellar vesicles (LUV)

Summary The evolution of the thermotropic properties of large unilamellar vesicles (LUV) made by the reverse-phase evaporation technique has been studied by differential scanning calorimetry (DSC) and by fluorescence polarization of the diphenylhexatriene probe inserted in the lipid phase. Lipid fluidity and transition temperatures of DL-a-dimyristoyl-and DL-a-dipalmitoyl-phosphatidylcholine vesicles were practically not modified at room temperature (19–20°C), even after several days. Because a better knowledge of the physico-chemical properties of LUV seems essential for its use as a model membrane or as a carrier of exogenous material into cells, we compare it with the stability of the widely used multilamellar (MLV) and sonicated unilamellar vesicles (SUV).     

Chlorpromazine causes vesicle population changes in the monoaminergic synapse of the rat caudate nucleus

Summary The population of monoaminergic synaptic vesicles in the rat caudate nucleus remained unchanged or slightly decreased 3 h after chlorpromazine (CP) administration, and clearly increased after 24 h. The diameter of synaptic vesicles became smaller when the vesicles increased. These findings suggest that CP causes presynaptic blocking in part of its actions and leads to a condition in which neural transmission is inactive. In the control animals, population of the vesicles tended to fluctuate following the circadian rhythm.     

Turnover of 5-hydroxydopamine in adrenergic nerves

Summary In adrenergic nerve endings of the guinea-pig vas deferens the population of small granular vesicles increases from 19% in control animals to 80–90% 1–3 h after the administration of 5-hydroxydopamine, and gradually declines to control values in 10 days. Large granular vesicles were also loaded but the loss of enhanced granulation was more rapid than in the small granular vesicles.M. R. C. Scholar. I am greatly indebted to Prof. G. Burnstock, Prof. G. Gray and Dr G. Gabella for helpful advice and criticism. The technical assistance of J. Barron and G. Barrett is gratefully acknowledged.     

Cholinergic and adrenergic innervation of the penis artery of the bull: transmitter concentrations and synaptic vesicles.

The penile artery of the bull contained significant amounts of acetylcholine, noradrenaline and dopamine, and its axon profiles contained either numerous small granular or agranular vesicles, as well as some large granular vesicles. In the dorsal metatarsal artery, only noradrenaline and dopamine were detectable, and the axon profiles observed contained numerous small granular vesicles. In the penile artery, the axons with small agranular vesicles, probably cholinergic axons, were in close contact with axons containing small granular vesicles. It is suggested that, in the penile artery of the bull, one of the functions of the cholinergic nerves is suppression of excitatory adrenergic neurotransmission.     

Cholinergic and adrenergic innervation of the penis artery of the bull: Transmitter concentrations and synaptic vesicles

Summary The penile artery of the bull contained significant amounts of acetylcholine, noradrenaline and dopamine, and its axon profiles contained either numerous small granular or agranular vesicles, as well as some large granular vesicles. In the dorsal metatarsal artery, only noradrenaline and dopamine were detectable, and the axon profiles observed contained numerous small granular vesicles. In the penile artery, the axons with small agranular vesicles, probably cholinergic axons, were in close contact with axons containing small granular vesicles. It is suggested that, in the penile artery of the bull, one of the functions of the cholinergic nerves is suppression of excitatory adrenergic neurotransmission.This study has been supported by grants from the Sigrid Jusélius Foundation (to O.E.), from the Medical Research Council of the Academy of Finland (to E.K.) and from the Magnus Bergvall Memorial Fund (to N.O.S.). Excellent technical assistance by Mrs Paula Hasenson and Miss Seija Ovaskainen is gratefully acknowledged.     

Different types of synaptic vesicles in axons of the retractor penis muscle of the bull.

Three types of axon profiles were observed in the smooth muscle of the retractor penis and the penile artery of the bull: 1. profiles containing small granular vesicles, presumably representing adrenergic axons; 2. profiles containing small agranular vesicles, presumably representing cholinergic axons; 3. profiles containing numerous large and small granular vesicles. The third type of profile was not found in the vas deferens or the metatarsal artery. It is therefore possible that this type of profile represents the non-adrenergic, non-cholinergic inhibitory nerves, the presence of which has previously been pharmacologically indicated in these tissues.     

Accumulation of3H-dopamine by synaptic vesicles from rat striatum in an impermeant medium

Summary The accumulation of³H-dopamine by synaptic vesicles from rat striatum was significantly stabilized in a membrane impermeant medium. The characteristics of dopamine accumulation by striatal vesicles were quite similar to those reported for dopamine accumulation by a whole brain vesicle preparation in the same medium, and were siginificantly different from the characteristics previously reported for vesicular accumulation of norepinephrine.Acknowledgments. This work was supported by grant NS 18752 (NIH) of the United States Public Health Service. Reprint requests to J. A. R.     

Different types of synaptic vesicles in axons of the retractor penis muscle of the bull

Summary Three types of axon profiles were observed in the smooth muscle of the retractor penis and the penile artery of the bull: 1. profiles containing small granular vesicles, presumably representing adrenergic axons; 2. profiles containing small agranular vesicles, presumably representing cholinergic axons; 3. profiles containing numerous large and small granular vesicles. The third type of profile was not found in the vas deferens or the metatarsal artery. It is therefore possible that this type of profile represents the non-adrenergic, non-cholinergic inhibitory nerves, the presence of which has previously been pharmacologically indicated in these tissues.This study has been supported by grants from the Sigrid Jusélius Foundation (to O. E.), from the Medical Research Council of the Academy of Finland (to E. K.) and from the Magnus Bergvall Memorial Fund (to N. O. S.). Excellent technical assistance by Mrs.Paula Hasenson is gratefully acknowledged.     

Photoreactivation of UV damage in cultured Drosophila cells

Cell survival and photoreactivation of 254 nm ultraviolet (UV) light damage in a wild type Drosophila cell line was assayed by colony formation in liquid medium. Fo, Fq, and extrapolation number for the exponential portion of survival curves are 21 J/m2, 3.6 J/m2, and 1.5 for non-photoreactivated cells and 110 J/m2, 11.2 J/m2, and 1.3 for those exposed to photoreactivating light. Maximal photoreactivation occurs at the 100 J/m2 region of the curve. At 10 and 50% survival, 75-80% of the UV damage was photoreactivable.     

Types of nerve terminals in fetal and neonatal rabbit myocardium

With the use of electron microscopy 4 types of axonal profiles were observed in the developing myocardium of rabbits: 1) adrenergic axons which contained mainly small dense-core vesicles and which presumably can store 5-hydroxy-dopamine; 2) cholinergic axons which contained small clear synaptic vesicles and which were acetylcholinesterase-positive; 3) axons which contained large vesicles filled with moderately electron-dense material and which resembled purinergic axons; and 4) profiles filled with mitochondria, vesicles of various sizes, lysosome-like bodies, and microtubules and which resembled sensory terminals.     

Sequential biogenesis of host cell membrane rearrangements induced by hepatitis C virus infection

Like most positive-strand RNA viruses, hepatitis C virus (HCV) forms a membrane-associated replication complex consisting of replicating RNA, viral and host proteins anchored to altered cell membranes. We used a combination of qualitative and quantitative electron microscopy (EM), immuno-EM, and the 3D reconstruction of serial EM sections to analyze the host cell membrane alterations induced by HCV. Three different types of membrane alteration were observed: vesicles in clusters (ViCs), contiguous vesicles (CVs), and double-membrane vesicles (DMVs). The main ultrastructural change observed early in infection was the formation of a network of CVs surrounding the lipid droplets. Later stages in the infectious cycle were characterized by a large increase in the number of DMVs, which may be derived from the CVs. These DMVs are thought to constitute the membranous structures harboring the viral replication complexes in which viral replication is firmly and permanently established and to protect the virus against double-stranded RNA-triggered host antiviral responses.     

Morphological evidence for tracer uptake at the active zones of stimulated frog neuromuscular junction

Lanthanum or ferritin added to the fixative were found in small and non-coated vesicles located at active zones in nerve-muscle preparations stimulated by potassium during cold aldehyde fixation. The presence of labeled vesicles at active zones supports the hypothesis that a double process of exo-endocytosis might occur under moderate stimulation conditions.     

Differences in cytochalasin D-induced surface alterations between chronic lymphocytic leukaemic and normal lymphocytes

Summary Cytochalasin D (CD) causes an unusual surface alteration in normal lymphocytes consisting of the formation of focal irregular club-shaped cell processes. Lymphocytes from chronic lymphocytic leukaemic cases did not show this change on exposure to CD. There was either no surface change or, in some cases, clear double-membrane lined vesicles were formed and appeared to be discharged from the cell. This difference in response may be related to the changes in cell membranes known to occur in malignant transformation.The study was supported by the National Cancer Institute of Canada.     

Differences in cytochalasin D-induced surface alterations between chronic lymphocytic leukaemic and normal lymphocytes

Cytochalasin D (CD) causes an unusual surface alteration in normal lymphocytes consisting of the formation of focal irregular club-shaped cell processes. Lymphocytes from chronic lymphocytic leukaemic cases did not show this change on exposure to CD. There was either no surface change or, in some cases, clear double-membrane lined vesicles were formed and appeared to be discharged from the cell. This difference in response may be related to the changes in cell membranes known to occur in malignant transformation.