Effect of brefeldin A (BFA) on the unique surface coat of pulmonary intravascular macrophages (PIMs) of sheep: Ultrastructural and cytochemical study

1993 ◽  
Vol 51 ◽  
pp. 18-19
Author(s):  
Baljit Singh
Keyword(s):  
Brefeldin A ◽  
Ultrastructural Feature ◽  
Surface Coat ◽  
Anterograde Transport ◽  
Cytochemical Study ◽  
Active Involvement ◽  
Electron Lucent ◽  
Pulmonary Intravascular Macrophages ◽  
Unique Surface

The PIM of sheep, calf, goat and horse has a characteristic ultrastructural feature in the form of a unique, heparin sensitive, globular surface coat present around the plasma membrane with an intervening electron lucent space of 32-40 nm. We previously showed the active involvement of this surface coat in the phagocytosis of tracer material like monastral blue and cationized ferritin. The surface coat is capable of reconstitution in vivo following disruption with heparin. The present study was aimed to investigate whether PIM is the source of surface coat or not. In the recent years the BFA has been extensively used to understand the secretory pathways in the cells because of its ability to cause a rapid and reversible block to the anterograde transport of proteins from the endoplasmic reticulum to the Golgi.Sheep (n=6) were weighed, their plasma volume was calculated indirectly and based on which a sufficient single intravenous dose of BFA was given so as to reach a concentration of 4-5 microgram/ml of plasma.

Ultrastructural study of uptake of monastral blue by the pulmonary intravascular macrophages of sheep in the presence and absence of surface coat

1992 ◽  
Vol 50 (1) ◽  
pp. 702-703
Author(s):  
B. Singh ◽  
D. S. Jassal ◽  
O. S. Atwal ◽  
K. Minhas
Keyword(s):  
Tannic Acid ◽  
Animal Species ◽  
Ultrastructural Level ◽  
Mononuclear Phagocyte ◽  
Surface Coat ◽  
Cell Periphery ◽  
Highly Sensitive ◽  
Pulmonary Intravascular Macrophages

Pulmonary intravascular macrophage (PIM) is an important mononuclear phagocyte of some animal species. In sheep these cells are actively involved in the clearance of microbes and endotoxins. By treating the tissue with tannic acid we have identified at the ultrastructural level a unique globular surface coat, arranged at a distance of 30-40 nm from the cell periphery, This coat is hypothesized to be lipoprotein in nature as tannic acid complexes with the globules to enhance their electron density. This surface coat is highly sensitive to in vitro lipolytic lipase digestion and in vivo heparin treatment.

scholarly journals Fusogenic Domains of Golgi Membranes Are Sequestered into Specialized Regions of the Stack that Can Be Released by Mechanical Fragmentation

1999 ◽  
Vol 145 (4) ◽  
pp. 673-688 ◽  
Author(s):  
Michel Dominguez ◽  
Ali Fazel ◽  
Sophie Dahan ◽  
Jacque Lovell ◽  
Louis Hermo ◽  
...  
Keyword(s):  
Brefeldin A ◽  
Maximal Activity ◽  
Anterograde Transport ◽  
Galactosyl Transferase ◽  
Highly Active ◽  
Golgi Transport ◽  
Transport Assay ◽  
Mechanical Fragmentation

A well-characterized cell-free assay that reconstitutes Golgi transport is shown to require physically fragmented Golgi fractions for maximal activity. A Golgi fraction containing large, highly stacked flattened cisternae associated with coatomer-rich components was inactive in the intra-Golgi transport assay. In contrast, more fragmented hepatic Golgi fractions of lower purity were highly active in this assay. Control experiments ruled out defects in glycosylation, the presence of excess coatomer or inhibitory factors, as well as the lack or consumption of limiting diffusible factors as responsible for the lower activity of intact Golgi fractions. Neither Brefeldin A treatment, preincubation with KCl (that completely removed associated coatomer) or preincubation with imidazole buffers that caused unstacking, activated stacked fractions for transport. Only physical fragmentation promoted recovery of Golgi fractions active for transport in vitro. Rate-zonal centrifugation partially separated smaller transport-active Golgi fragments with a unique v-SNARE pattern, away from the bulk of Golgi-derived elements identified by their morphology and content of Golgi marker enzymes (N-acetyl glucosaminyl and galactosyl transferase activities). These fragments released during activation likely represent intra-Golgi continuities involved in maintaining the dynamic redistribution of resident enzymes during rapid anterograde transport of secretory cargo through the Golgi in vivo.

The Fine Structure of Glycocalyx in Human Spermatozoa. A High Resolution Cytochemical Study

1973 ◽  
Vol 31 ◽  
pp. 640-641
Author(s):  
P. Hernández-Jáuregui ◽  
A. Sosa ◽  
A. González Angulo
Keyword(s):  
Negative Charge ◽  
Iron Hydroxide ◽  
Human Spermatozoa ◽  
Surface Coat ◽  
Cell Surfaces ◽  
Colloidal Iron ◽  
Cytochemical Study ◽  
Specific Permeability ◽  
Extracellular Glycoprotein ◽  
Mammalian Spermatozoa

Glycocalyx is the name given by Bennett to the extracellular glycoprotein coat present in some cell surfaces. It appears to play an important role in cell properties such as antigenicity, cell adhesivity, specific permeability, and ATP ase activity. In the sperm this coat can be directly related to such important phenomena as capacitation and fertilization. The presence of glycocalyx in invertebrate spermatozoa has already been demonstrated. Recently Yanagimachi et al. has determined the negative charges on sperm surfaces of mammalian spermatozoa including man, using colloidal iron hydroxide. No mention was made however of the outer surface coat as composed of substances other than those confering a negative charge. The purpose of this work was therefore to determine the presence of a glycocalyx in human spermatozoa using alcian blue and lanthanum staining.

In vitro and in vivo polysaccharides assembly: ultrastructural and cytochemical study of growing plant cell wall components.

1978 ◽  
Vol 36 (2) ◽  
pp. 434-435
Author(s):  
D. Reis ◽  
B. Vian ◽  
J. C. Roland
Keyword(s):  
Cell Wall ◽  
Self Assembly ◽  
Plant Cell Wall ◽  
Higher Plants ◽  
Three Dimensional ◽  
Cytochemical Study ◽  
Wall Components

Wall morphogenesis in higher plants is a problem still open to controversy. Until now the possibility of a transmembrane control and the involvement of microtubules were mostly envisaged. Self-assembly processes have been observed in the case of walls of Chlamydomonas and bacteria. Spontaneous gelling interactions between xanthan and galactomannan from Ceratonia have been analyzed very recently. The present work provides indications that some processes of spontaneous aggregation could occur in higher plants during the formation and expansion of cell wall.Observations were performed on hypocotyl of mung bean (Phaseolus aureus) for which growth characteristics and wall composition have been previously defined.In situ, the walls of actively growing cells (primary walls) show an ordered three-dimensional organization (fig. 1). The wall is typically polylamellate with multifibrillar layers alternately transverse and longitudinal. Between these layers intermediate strata exist in which the orientation of microfibrils progressively rotates. Thus a progressive change in the morphogenetic activity occurs.

Mitochondrial matrix calcium ions regulate energy production in myocardium: A cytochemical study

1990 ◽  
Vol 48 (2) ◽  
pp. 166-167
Author(s):  
W.A. Jacob ◽  
R. Hertsens ◽  
A. Van Bogaert ◽  
M. De Smet
Keyword(s):  
Energy Metabolism ◽  
Calcium Ions ◽  
Energy Production ◽  
Regulation Of Respiration ◽  
Free Calcium ◽  
Mitochondrial Matrix ◽  
Cytochemical Study ◽  
Nmr Techniques

In the past most studies of the control of energy metabolism focus on the role of the phosphorylation potential ATP/ADP.Pi on the regulation of respiration. Studies using NMR techniques have demonstrated that the concentrations of these compounds for oxidation phosphorylation do not change appreciably throughout the cardiac cycle and during increases in cardiac work. Hence regulation of energy production by calcium ions, present in the mitochondrial matrix, has been the object of a number of recent studies.Three exclusively intramitochondnal dehydrogenases are key enzymes for the regulation of oxidative metabolism. They are activated by calcium ions in the low micromolar range. Since, however, earlier estimates of the intramitochondnal calcium, based on equilibrium thermodynamic considerations, were in the millimolar range, a physiological correlation was not evident. The introduction of calcium-sensitive probes fura-2 and indo-1 made monitoring of free calcium during changing energy metabolism possible. These studies were performed on isolated mitochondria and extrapolation to the in vivo situation is more or less speculative.

The Ullrastructure of Platelet Participation in Hemostasis

1965 ◽  
Vol 13 (01) ◽  
pp. 065-083 ◽  
Author(s):  
Shirley A. Johnson ◽  
Ronaldo S. Balboa ◽  
Harlan J. Pederson ◽  
Monica Buckley
Keyword(s):  
Platelet Aggregation ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Guinea Pigs ◽  
Platelet Factor ◽  
Mesenteric Vessels ◽  
Platelet Aggregates ◽  
Electron Lucent

SummaryThe ultrastructure of platelet aggregation in vivo in response to bleeding brought about by transection of small mesenteric vessels in rats and guinea pigs has been studied. Platelets aggregate, degranulate and separating membranes disappear in parallel with fibrin appearance which is first seen at several loci after 30 seconds of bleeding. About 40 per cent of the electron opaque granules, some of which contain platelet factor 3 have disappeared after one minute of bleeding while the electron lucent granules increase by 70 per cent suggesting that some of them may be empty vesicles. Most of the platelet aggregates of the random type disappear leaving clumped red blood cells entrapped by a network of fibrin fibers which emanate from the remains of platelet aggregates of the rosette type to maintain hemostasis.

Catecholaminergic innervation of white adipose tissue in Siberian hamsters

1995 ◽  
Vol 268 (3) ◽  
pp. R744-R751 ◽  
Author(s):  
T. G. Youngstrom ◽  
T. J. Bartness
Keyword(s):  
Adipose Tissue ◽  
White Adipose Tissue ◽  
Neural Control ◽  
Fat Pad ◽  
Anterograde Transport ◽  
Siberian Hamsters ◽  
Lipid Stores ◽  
Catecholaminergic Innervation ◽  
Fat Pads

When Siberian hamsters are transferred from long summerlike days (LDs) to short winterlike days (SDs) they decrease their body weight, primarily as body fat. These SD-induced decreases in lipid stores are not uniform. Internally located white adipose tissue (WAT) pads are depleted preferentially of lipid, whereas the more externally located subcutaneous WAT pads are relatively spared. These data suggest a possible differential sympathetic neural control over catecholamine-induced lipolysis and that lipolytic rates are greater for internal vs. external WAT pads. Moreover, if these differential rates of lipolysis are due to differential sympathetic nervous system (SNS) drives on the pads, then fat pad-specific catecholaminergic innervation may exist. Therefore, we tested whether inguinal WAT (IWAT; an external pad) and epididymal WAT (EWAT; an internal pad) were innervated differentially. In addition, we tested whether norepinephrine (NE) turnover (TO) reflected the presumed greater SNS drive on EWAT vs. IWAT after SD exposure. Injections of fluorescent tract tracers [Fluoro-Gold or indocarbocyanine perchlorate (DiI)] demonstrated projections from the SNS ganglia T13-L3 to both fat pads. Retrograde labeling revealed a relatively separate pattern of distribution of labeled neurons in the ganglia projecting to each pad. In vivo anterograde transport of DiI resulted in labeling in both IWAT and EWAT that included staining around individual adipocytes and occasionally retrogradely labeled cells. The proportionately greater decrease in EWAT compared with IWAT mass after 5 wk of SD exposure was reflected in greater EWAT NE TO than found in their LD counterparts for this pad.(ABSTRACT TRUNCATED AT 250 WORDS)

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