Assays of Megakaryocyte Development: Cytoplasm, Storage Granules, and Demarcation Membranes

2004 ◽  
pp. 323-346
Author(s):  
Arnaud Drouin ◽  
Gulie Alimardani ◽  
Elisabeth M. Cramer
Keyword(s):  
Storage Granules

Antithrombin III Antigen in Human Platelets

1985 ◽  
Vol 54 (03) ◽  
pp. 599-602 ◽  
Author(s):  
M Léon Alhenc-Gelas ◽  
M Aiach ◽  
A Gorenflot ◽  
J P Andreux
Keyword(s):  
Arachidonic Acid ◽  
Enzyme Immunoassay ◽  
Antithrombin Iii ◽  
Human Platelets ◽  
Mean Value ◽  
Normal Blood ◽  
Freezing And Thawing ◽  
Healthy Donors ◽  
At Iii ◽  
Storage Granules

SummaryImmunoreactive AT III was found in human platelets. AT III antigen was quantified in platelets taken from each of 17 healthy donors by a specific competitive enzyme immunoassay using purified AT III and AT III antibodies. AT III antigen levels in extracts of washed platelets disrupted by freezing and thawing ranged from 32 to 140 ng per 109 platelets with a mean value of 70.3 ± 27.3. When stimulated by arachidonic acid, the platelets released AT III antigen together with immunoreactive fibrinogen. These results show that AT III is present in platelets at a level corresponding to approximately 0.01% of total antithrombin in normal blood, and suggest that platelet AT III, like fibrinogen, is contained in the storage granules.

scholarly journals Transport and storage of serotonin by thrombin-treated platelets.

1975 ◽  
Vol 65 (2) ◽  
pp. 359-372 ◽  
Author(s):  
H J Reimers ◽  
D J Allen ◽  
I A Feuerstein ◽  
J F Mustard
Keyword(s):  
Storage Capacity ◽  
Platelet Membrane ◽  
Transport Rate ◽  
Primary Reason ◽  
High Concentration ◽  
Serotonin Content ◽  
Amine Storage ◽  
Storage Granules ◽  
And Storage ◽  
Amine Storage Granules

Repeated thrombin treatment of washed platelets prepared from rabbits can decrease the serotonin content of the platelets by about 80%. When these platelets are deaggregated they reaccumulate serotonin but their storage capacity for serotonin is reduced by about 60%. If thrombin-pretreated platelets are allowed to equilibrate with a high concentration of serotonin (123 mu M), they release a smaller percentage of their total serotonin upon further thrombin treatment, in comparison with the percentage of serotonin released from control platelets equilibrated with the same concentration of serotonin calculations indicate that in thrombin-treated platelets reequilibrated with serotonin, two-thirds of the serotonin is in the granule compartment and one-third is in the extragranular compartment, presumably the cytoplasm. Analysis of the exchange of serotonin between the suspending fluid and the platelets showed that thrombin treatment does not alter the transport rate of serotonin across the platelet membrane and does not cause increased diffusion of serotonin from the platelets into the suspending fluid. The primary reason for the reduced serotonin accumulation by the thrombin-treated platelets appears to be loss of amine storage granules or of the storage capacity within the granules.

Structure and composition of urate storage granules from the fat body of Manduca sexta

1990 ◽  
Vol 20 (2) ◽  
pp. 203-214 ◽  
Author(s):  
James S. Buckner ◽  
Thomas A. Henderson ◽  
Daniel D. Ehresmann ◽  
George Graf
Keyword(s):  
Manduca Sexta ◽  
Fat Body ◽  
Storage Granules

Distribution of anionic sites on surface of B cell granule and plasma membranes: a study using cationic ferritin

1977 ◽  
Vol 27 (1) ◽  
pp. 289-301
Author(s):  
S.L. Howell ◽  
M. Tyhurst
Keyword(s):  
B Cell ◽  
Plasma Membranes ◽  
Calcium Concentration ◽  
Anionic Sites ◽  
Neuraminidase Treatment ◽  
Visual Probe ◽  
Cell Plasma ◽  
Granule Membrane ◽  
Pancreatic B Cells ◽  
Storage Granules

The distribution of anionic sites on the membranes of rat pancreatic B cells and of their storage granules has been studied by the use of a visual probe of cationic ferritin. Membranes of isolated storage granules possessed a net negative charge which was apparently evenly distributed; the number of anionic sites was not markedly altered by prior incubation of the granules with neuraminidase or with 10(−5) to 2 X 10(−3) M calcium chloride. Distribution of charges along B cell plasma membranes was less uniform but was similarly unaffected by alterations of calcium concentration, or by neuraminidase treatment. However, during the fusion of plasma membrane and granule membrane which occurs in exocytosis, the emerging granule membrane was found to be devoid of anionic sites. The implications of these findings for the regulation of insulin secretion by exocytosis are discussed.

An Ultrastructural Study of the Distal Epidermis and the Occurrence of Subcuticular Bacteria in the Gutless Tubificid Phallodrilus Albidus (Oligochaeta:Annelida).

1982 ◽  
Vol 30 (2) ◽  
pp. 327 ◽  
Author(s):  
KS Richards ◽  
TP Fleming ◽  
BGM Jamieson
Keyword(s):  
Population Density ◽  
Ultrastructural Study ◽  
Cytoplasmic Membrane ◽  
Apical Membrane ◽  
Peripheral Region ◽  
Epidermal Cells ◽  
Absorptive Function ◽  
Inherent Feature ◽  
Storage Granules ◽  
Amorphous Zone

The typically annelid cuticle of Phallodrilus albidus has an increased population density of epicuticular projections, but this is not thought to be related to its gutless condition. The irregular outline of the apical membrane of the epidermal cells is an inherent feature, possibly enhancing an absorptive function. The cuticle-epidermal interface is characterized by multigranular bodies, rod-shaped bacteria and filiform structures. The multigranular bodies are present in the postclitellar region only, coinciding with the chalkiness of living specimens. The bacteria occur throughout the entire length of the worm, their presence exaggerating the irregularities of the apical membrane. The bacterial cytoplasmic membrane, in contrast to the limiting membrane, was difficult to resolve. Between the two membranes is an amorphous zone. Storage granules of a carbohydrate-rich complex are located peripherally and the bacterial core contains a reticulum of DNA threads. Filiform structures, ultrastructurally similar to the bacterial peripheral region, are numerous, especially where the bacteria are carbohydrate-rich. Connections with the bacterial bodies were observed, but infrequently. The non-pathologic association between the subcuticular bacteria and the gutless tubificid is discussed.

The subcellular concentration of ions and elements in thin cryosections of onion root meristem cells. An electron-probe EDS study

1984 ◽  
Vol 72 (1) ◽  
pp. 295-306
Author(s):  
I.L. Cameron ◽  
K.E. Hunter ◽  
N.K. Smith
Keyword(s):  
Electron Probe ◽  
Dry Weight ◽  
Cell Types ◽  
Meristematic Cells ◽  
Freeze Dried ◽  
Concentration Of Ions ◽  
Intracellular Compartments ◽  
Root Meristematic Cells ◽  
Storage Granules ◽  
First Time

Quantitative electron-probe energy dispersive X-ray microanalysis has, for the first time, been accomplished at a subcellular level in plant tissue using cryofixed and thin freeze-dried cryosections. The subcellular concentrations of Na+, Cl-, K+, P, S, Mg2+ and Ca2+ were measured in mol/kg dry weight in two types of root meristematic cells of the onion, Allium cepa. The cell wall of the meristematic cells had much higher concentrations of K+ and Ca2+ than was found in the intracellular compartments. Storage granules in the protoderm cells were about 6–12 times lower in P and were about four times higher in S as compared to other intracellular compartments. Comparison between the concentrations of ions and other elements in meristematic plant cells and in mouse cardiac myocytes confirms that major differences in cytoplasmic Na+ and Cl- concentrations do indeed exist between these cell types.

Calcium distribution in islets of Langerhans: a study of calcium concentrations and of calcium accumulation in B cell organelles

1975 ◽  
Vol 19 (2) ◽  
pp. 395-409
Author(s):  
S.L. Howell ◽  
W. Montague ◽  
M. Tyhurst
Keyword(s):  
Endoplasmic Reticulum ◽  
Cyclic Amp ◽  
B Cell ◽  
Islets Of Langerhans ◽  
Cyclic Gmp ◽  
Cell Organelles ◽  
Calcium Accumulation ◽  
Labile Pool ◽  
Storage Granules ◽  
Rat Islets Of Langerhans

Calcium concentrations of various pancreatic B cell organelles have been determined by X-ray microanalysis of areas of frozen sections of unfixed rat islets of Langerhans. Highest concentrations were detected in storage granules and in mitochondria, although calcium was also present in nuclei, in areas of endoplasmic reticulum and of cytoplasm. Accumulation of 45Ca by isolated organelles has been studied in homogenates and isolated subcellular fractions of rat islets of Langerhans. In the presence of a permeant anion (oxalate or phosphate), accumulation of 45Ca into mitochondria and microsomes was strongly stimulated by ATP. This net uptake was diminished during incubation of homogenates or of a mitochondria plus storage granule-rich fraction in the presence of cyclic AMP, dibutyryl cyclic GMP; 2:4-dinitrophenol or of ruthenium red. Investigations of the characteristics of 45Ca accumulation by homogenates prepared from storage granule-depleted islets showed no differences from those of normal islets, suggesting that the granules do not represent an important labile pool of calcium. With the exception of cyclic AMP and cyclic GMP none of the insulin secretagogues tested (glucose, leucine, arginine, adrenalin, noradrenalin, theophylline, glibenclamide) altered calcium accumulation by islet homogenates. On the basis of absolute calcium levels and of 45Ca uptake studies it is concluded that islet B cells contain a readily exchangeable mitochondrial calcium pool, and an endoplasmic reticulum pool containing a lower concentration of calcium which is also readily exchangeable. The storage granules, despite their high calcium content, do not appear to constitute a labile pool. It seems likely that the labile mitochondria and endoplasmic reticulum pools play a predominant role in the regulation of cytoplasmic free calcium levels, which may in turn be important in the regulation of rates of insulin secretion.

The Golgi Material and Mitochondria in the Salivary Glands of the Larva of Drosophila Melanogaster

1948 ◽  
Vol s3-89 (8) ◽  
pp. 401-414
Author(s):  
W. SIANG HSU
Keyword(s):  
Salivary Glands ◽  
Golgi Body ◽  
Anterior Portion ◽  
Golgi Bodies ◽  
Gland Cells ◽  
Salivary Gland Cells ◽  
Visible Part ◽  
Show Evidence ◽  
Storage Granules ◽  
Reserve Food

1. The salivary glands in the larvae of Drosophila show evidence of serving two functions: (1) production of digestive secretion, (2) accumulation of reserve food for the period of pupation. The two functions proceed simultaneously within the same cell during certain stages of its development. 2. A single droplet of digestive material has been seen to originate and grow within each Golgi body in the gland-cells. When a certain size is reached the droplet is released into the cytoplasm and by the fusion of two or more of them bigger vacuoles are formed. The secretory material is discharged into the lumen by means of a merocrine mechanism. Neither mitochondria nor nucleus has been observed to take any visible part in the elaboration of secretion droplets. 3. The storage granules found in older and larger cells have been observed to be direct transformations of chondriomites, and neither the Golgi material nor the nucleus shows any sign of participation in the formation of these granules. 4. From the standpoint of morphology and behaviour, the Golgi bodies found in the salivary gland cells are the same as found in the cells of the glandular portion of the proventriculus and the epithelium of the anterior portion of the midgut of the larva. 5. My observations do not lend themselves convincingly to a two-component conception of the structure of Golgi bodies.

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