Platelet dense bodies: a quantitative microprobe analysis

1976 ◽  
Vol 20 (2) ◽  
pp. 441-457
Author(s):  
R.J. Skaer ◽  
J.P. Emmines ◽  
P.D. Peters
Keyword(s):  
Adenine Nucleotides ◽  
Lipid Extraction ◽  
Dry Weight ◽  
Atomic Ratio ◽  
Human Platelets ◽  
Control Mechanisms ◽  
Inorganic Pyrophosphate ◽  
Dense Bodies ◽  
The Mean ◽  
Chloroform Methanol

The electron microprobe shows that the dense bodies of human platelets have a mean P:Ca peak ratio of 1–2. After treatment with dry chloroform/methanol this falls to 0-89. These ratios vary slightly from patient to patient. The use of calcium and phosphorus standards enables these peak ratios to be converted to atomic ratios. The size of the phosphorus peak remaining after lipid extraction was given absolute terms with reference to the known quantities of adenine nucleotides and inorganic pyrophosphate in dense bodies. From the mean P:Ca atomic ratio of 1–76 the quantity of calcium in dense bodies was 0-6 mg/10(11) platelets or 2–97 mg Ca/g dry weight of platelets. This is within the published range for total platelet calcium. If all the phosphorus extracted by lipid solvents were phospholipid there would be 5–65 mg/10(11) platelets, and it would occupy most of the space inside dense bodies. The dense bodies of pig platelets contain both magnesium and calcium in a varying ratio to each other. These results are discussed in relation to control mechanisms that may influence aggregation.

scholarly journals Inorganic pyrophosphate is located primarily in the mitochondria of the hepatocyte and increases in parallel with the decrease in light-scattering induced by gluconeogenic hormones, butyrate and ionophore A23187

1988 ◽  
Vol 254 (2) ◽  
pp. 379-384 ◽  
Author(s):  
A M Davidson ◽  
A P Halestrap
Keyword(s):  
Light Scattering ◽  
Adenine Nucleotides ◽  
Hormone Treatment ◽  
Subcellular Fractionation ◽  
Liver Mitochondria ◽  
Cell Protein ◽  
Ionophore A23187 ◽  
Inorganic Pyrophosphate ◽  
Rat Liver Cells ◽  
The Mean

1. The effects of a variety of hormones on the PPi content and light-scattering of isolated rat liver cells was studied. 2. The basal PPi content was about 130 pmol/mg of cell protein, and increased after hormone addition, in parallel with a decrease in light-scattering which we have observed previously [Quinlan, Thomas, Armston & Halestrap (1983) Biochem. J. 214, 395-404]. 3. The mean increases in PPi content with the agonists shown (as pmol/mg of protein) were: 0.1 microM-glucagon, 25; 20 microM-phenylephrine, 30; 25 nM-vasopressin, 127; glucagon + phenylephrine, 115; glucagon + vasopressin, 382; 100 microM-ADP, 50; 15 microM-A23187, 72; 1 mM-butyrate, 80. 4. In the absence of extracellular Ca2+, vasopressin had little effect on either the PPi content or the light-scattering of hepatocytes. 5. The magnitude of the increase in PPi content correlated with that of the decrease in light-scattering irrespective of the stimulating agent, provided that the PPi did not exceed 300 pmol/mg of protein. Above this value little additional change in light-scattering was observed. 6. Subcellular fractionation showed that over 90% of the cellular PPi was intramitochondrial in both control and stimulated cells. 7. The data support the conclusions of previous experiments using isolated liver mitochondria [Davidson & Halestrap (1987) Biochem. J. 246, 715-723] that hormones increase the mitochondrial matrix volume through a Ca2+-induced rise in matrix [PPi]. 8. It is further proposed that this increase in mitochondrial [PPi] allows entry of ADP into the mitochondria in exchange for PPi and is therefore responsible for the increase in total mitochondrial adenine nucleotides observed after hormone treatment.

In situ observation of Dense-Body Release from Hydrated Human Platelets

1977 ◽  
Vol 35 ◽  
pp. 646-647
Author(s):  
S.W. Hui ◽  
J.L. Costa ◽  
M.A. Smith ◽  
C.M. Strozewski
Keyword(s):  
Electron Microscope ◽  
Dense Body ◽  
Adenine Nucleotides ◽  
Human Platelets ◽  
In Situ Observation ◽  
Citrate Buffer ◽  
Dense Granules ◽  
Dense Bodies ◽  
Carbon Coated ◽  
Beam Dose

Dense bodies, electron-dense granules are believed to be storage sites for large pools of platelet serotonin, pyrophosphate, adenine nucleotides, and calcium. In order to prove that dense bodies exist as such in living platelets, we examined hydrated human platelets in the electron microscope, utilizing the differentially pumped hydration chamber.Human platelets were resuspended in the sodium chloride-Tris-citrate buffer with 0.35% bovine serum albumin, and were allowed to settle on carbon-coated grids covered with a thin film of liquid. Specimens were viewed and photographed at 100 kV in a Siemens 1A electron microscope equipped with an environmental chamber. The beam dose per micrograph was 5 x 10-5 coulombs/cm2. Although details of some platelets were obscured by a thick film of water, dense bodies were clearly visible in a large proportion of the platelets photographed (Figure 1). The distribution of platelets by dense-body content was similar to that described previously for air-dried whole mounts.

scholarly journals Optimization of a novel lipid extraction process from microalgae

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Xiaojie Ren ◽  
Chao Wei ◽  
Qi Yan ◽  
Xin Shan ◽  
Mengyun Wu ◽  
...  
Keyword(s):  
Water Treatment ◽  
Organic Solvents ◽  
Total Lipid ◽  
Extraction Method ◽  
Treatment Time ◽  
Lipid Extraction ◽  
Dry Weight ◽  
Extraction Solvent ◽  
Lipid Yield ◽  
Chloroform Methanol

AbstractPrevious study found that the solvent extraction efficiency of lipid in microalgae could be greatly improved by washing algae cells before the second time extraction. Based on the "organic solvents–water–organic solvents" method, this research further studied the effect of four solvent systems (acetone, chloroform/methanol, chloroform/methanol/water, dichloromethane/methanol), two types of water treatment (vortex and ultrasonic), three water treatment time gradient (0 s, 30 s, 120 s) on the lipid extraction at three different microalgae growth stages (3rd day, 5th day, 9th day). The results show that the combination of water treatment type, treatment time and solvent is very important to the efficiency of lipid extraction. The total lipid extracted was generally increased by 10–30% after water treatment. Especially under the condition of 120 s vortex water treatment with dichloromethane/methanol as extraction solvent, the total lipid extracted increased by 61.14%. In addition, microalgae cells at different culture stages had different sensitivity to water treatment. In this study, under the combination of chloroform/methanol/water as extraction solvent and vortex water treatment for 120 s, the highest lipid yield was obtained on the ninth day of cell culture, which accounts 47.88% of the cell dry weight (478 mg/g cell dry weight). The changes of cell morphology and structure after water treatment were studied by scanning electron microscope, and it was found that water treatment could seriously destroy the cell membrane damaged by solvent, thus promoting the release of lipids. This study further optimizes the "solvent–water–solvent" lipid extraction method, which neither produces impurities nor damages the lipid quality, and can reduce the amount of organic solvent applied in the classical lipid extraction method with the same lipid yield, so it has a broad application prospect.

scholarly journals Optimization of cell wall disruption and lipid extraction methods by combining different solvents from wet microalgae

2021 ◽  
Author(s):  
Daryush Arabian
Keyword(s):  
Cell Wall ◽  
Lipid Extraction ◽  
Dry Weight ◽  
Extraction Methods ◽  
Biodiesel Production ◽  
Cell Wall Disruption ◽  
Bead Mill ◽  
Wet Microalgae ◽  
Disruption Method ◽  
Chloroform Methanol

Microalgae have emerged as one of the most promising options for biodiesel production over the past few decades. Lipid extraction from microalgae for biodiesel production as a bottleneck of biodiesel production technology was the main purpose of this study. In this study different methods of the cell wall disruption were compared. Then, two methods of ultrasound and bead mill were used as methods of the cell wall disruption. The maximum lipid extracted by ultrasound was 17.10% and by bead mill was 15.16% (based on microalgae biomass dry weight). After the cell wall disruption of microalgae, for lipid extraction, chloroform-methanol solvent combination was used as a high extraction method and hexane-ethanol solvent combination was used as an environmentally friendly method. In this regard, the effect of solvent to biomass ratio, temperature and extraction time was investigated and the optimal results for chloroform-methanol solvent combination were 8 ml/g, 45°C and 60 minutes, respectively, and for hexane-ethanol combination were 6 ml/g, 35◦C and 73 minutes, respectively. Under these optimal conditions, the highest amount of extracted lipid from Chlorella vulgaris with a moisture content of 87.50%, and ultrasound as a cell wall disruption method were obtained 20.39% and 16.41% (based on microalgae dry weight) with a combination of chloroform-methanol solvents and hexane-ethanol respectively. Also the highest extraction rates of 17.63% and 13.85% were obtained for the combination of chloroform-methanol and hexane-ethanol solvents, respectively by bead milling as cell wall disruption method

Monoamine Oxidase and Other Mitochondrial Enzymes in Density Subpopulations of Human Platelets

1988 ◽  
Vol 59 (01) ◽  
pp. 029-033 ◽  
Author(s):  
K G Chamberlain ◽  
D G Penington
Keyword(s):  
Monoamine Oxidase ◽  
Protein Concentration ◽  
Close Correlation ◽  
Human Platelets ◽  
Mitochondrial Enzymes ◽  
Density Fractions ◽  
Percoll Gradients ◽  
Normal Human ◽  
The Mean ◽  
Very High

SummaryNormal human platelets have been separated according to density on continuous Percoll gradients and the platelet distribution divided into five fractions containing approximately equal numbers of platelets. The mean volumes and protein contents of the platelets in each fraction were found to correlate positively with density while the protein concentration did not differ significantly between the fractions. Four mitochondrial enzymes (monoamine oxidase, glutamate dehydrogenase, cytochrome oxidase and NADP-dependent isocitrate dehydrogenase) were assayed and their activities per unit volume were found to increase in a very similar monotonie fashion with platelet density. When MAO and GDH were assayed on the same set of density fractions the correlation between the two activities was very high (r = 0.94–1.00, p <0.001) and a similar close correlation was found between MAO and ICDH. The results support the hypothesis that high density platelets either have a higher concentration of mitochondria or have larger mitochondria than low density platelets.

Relationship Between Mepacrine-Labelled Dense Body Number, Platelet Capacity to Accumulate 14C-5-HT and Platelet Density in the Bernard-Soulier and Hermansky-Pudlak Syndromes

1979 ◽  
Vol 42 (02) ◽  
pp. 694-704 ◽  
Author(s):  
F Rendu ◽  
A T Nurden ◽  
M Lebret ◽  
J P Caen
Keyword(s):  
Dense Body ◽  
Human Subjects ◽  
Human Platelets ◽  
Dense Bodies ◽  
Storage Organelle ◽  
Hereditary Disorders ◽  
Labelling Procedure ◽  
Normal Human ◽  
Hermansky Pudlak Syndrome ◽  
Bernard Soulier Syndrome

SummaryWe have used the mepacrine-labelling procedure to measure the dense body (serotonin storage organelle) content of the platelets of 2 hereditary disorders where abnormalities in dense body number were suspected. The platelets were incubated with mepacrine and examined by fluorescence microscopy. A mean number of 5.4 ± 0.8 (SD) dense bodies per platelet was calculated from the data obtained using platelets isolated from 40 normal human subjects. In contrast the platelets of 2 patients with the Bernard-Soulier syndrome contained an average of 14 and 17 labelled granules. This increase was associated with a much greater capacity of the platelets to accumulate 14C-5-HT. The opposite result was obtained using the platelets from 2 patients with the Hermansky-Pudlak syndrome which contained few granules labelled by mepacrine and took up less 14C-5-HT than normal human platelets. Centrifugation of the patients’ platelets on discontinuous sucrose gradients showed that the platelets of the 2 Bemard-Soulier patients were much denser than normal whereas a high proportion of low density platelets was observed in the Hermansky-Pudlak syndrome. These results further define the platelet abnormalities in the two syndromes and suggest that dense body number may be one of the factors governing platelet density.

scholarly journals Loss of 111Indium as indicator of platelet injury

Blood ◽  
1981 ◽  
Vol 58 (2) ◽  
pp. 350-353 ◽  
Author(s):  
JH Joist ◽  
RK Baker
Keyword(s):  
Small Molecules ◽  
Adenine Nucleotides ◽  
Human Platelets ◽  
Metabolic Energy ◽  
Platelet Factor ◽  
Platelet Protein ◽  
Threshold Rate ◽  
Immune Injury ◽  
Triton X

Abstract We previously demonstrated that platelets can be labeled with 111Inoxine with high labeling efficiency and that 111In is not liberated from labeled platelets during the platelet release reaction or prolonged in vitro storage. In view of these findings, we examined the potential usefulness of loss of 111In from labeled platelets as an indicator or platelet damage by comparing the loss of 111In with that of 51Cr and LDH (in some experiments also with platelet factor 3 availability) under different conditions of platelet injury. When washed human platelets labeled with either 51Cr-chromate or 111In-oxine were exposed to increasing concentrations of detergents (Triton X-100, lysolecithin), threshold, rate, and extent of loss of 111In, 51Cr and, LDH were similar. In contrast, when labeled platelets were depleted of metabolic energy by incubation in glucose-free Tyrode albumin solution or glucose-depleted plasma in the presence of antimycin A and 2-deoxy-D- glucose, loss of 51Cr (and PF3a) occurred earlier and progressed at a faster rate than that of 111In or LDH. Similar results were obtained when platelets were exposed to increasing concentrations of PlA1 antibody, causing complement-mediated immune injury. The findings indicate that with certain agents that cause rapid platelet disruption (lysis), different platelet constituents are lost at similar rates. However, under conditions of more subtle or slowly progressive platelet injury, small molecules such as adenine nucleotides (51Cr) may escape earlier and at faster rates than larger molecules such as LDH or 111In- binding platelet protein. Thus, neither 111In loss nor LDH loss appear to be suitable indicators for sublytic or prelytic platelet injury.

scholarly journals Admixing Chaff with Straw Increased the Residues Collected without Compromising Machinery Efficiencies

Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1766 ◽  
Author(s):  
Alessandro Suardi ◽  
Sergio Saia ◽  
Walter Stefanoni ◽  
Carina Gunnarsson ◽  
Martin Sundberg ◽  
...  
Keyword(s):  
Energy Production ◽  
Dry Weight ◽  
Global Scale ◽  
Unit Weight ◽  
Residual Biomass ◽  
Energy Needs ◽  
The Mean ◽  
Field Efficiency ◽  
The One ◽  
Staple Crop

The collection of residues from staple crop may contribute to meet EU regulations in renewable energy production without harming soil quality. At a global scale, chaff may have great potential to be used as a bioenergy source. However, chaff is not usually collected, and its loss can consist of up to one-fifth of the residual biomass harvestable. In the present work, a spreader able to manage the chaff (either spreading [SPR] on the soil aside to the straw swath or admixed [ADM] with the straw) at varying threshing conditions (with either 1 or 2 threshing rotors [1R and 2R, respectively] in the combine, which affects the mean length of the straw pieces). The fractions of the biomass available in field (grain, chaff, straw, and stubble) were measured, along with the performances of both grain harvesting and baling operations. Admixing chaff allowed for a slightly higher amount of straw fresh weight baled compared to SPR (+336 kg straw ha−1), but such result was not evident on a dry weight basis. At the one time, admixing chaff reduced the material capacity of the combine by 12.9%. Using 2R compared to 1R strongly reduced the length of the straw pieces, and increased the bale unit weight; however, it reduced the field efficiency of the grain harvesting operations by 11.9%. On average, the straw loss did not vary by the treatments applied and was 44% of the total residues available (computed excluding the stubble). In conclusion, admixing of chaff with straw is an option to increase the residues collected without compromising grain harvesting and straw baling efficiencies; in addition, it can reduce the energy needs for the bale logistics. According to the present data, improving the chaff collection can allow halving the loss of residues. However, further studies are needed to optimise both the chaff and the straw recoveries.

scholarly journals Effects of antimycin A and 2-deoxyglucose on secretion in human platelets. Differential inhibition of the secretion of acid hydrolases and adenine nucleotides

1979 ◽  
Vol 182 (2) ◽  
pp. 413-419 ◽  
Author(s):  
Holm Holmsen ◽  
Linda Robkin ◽  
H. James Day
Keyword(s):  
Shape Change ◽  
Adenine Nucleotides ◽  
Human Platelets ◽  
Dense Granule ◽  
Metabolic Inhibitors ◽  
Antimycin A ◽  
Acid Hydrolase ◽  
Acid Hydrolases ◽  
Dense Granule Secretion ◽  
Granule Secretion

1. Shape change, aggregation and secretion of dense-granule constituents in platelets differ in their dependence on cellular energy metabolism. The possibility that such a difference also exists between secretion of dense-granule constituents and acid hydrolases was investigated. 2. Human platelets were incubated with [14C]adenine in plasma, and then washed and resuspended in salt solutions. The effects of incubating the cells with antimycin A and 2-deoxyglucose on the concentrations of [14C]ATP, ADP, AMP, IMP and inosine plus hypoxanthine and on thrombin-induced secretion of ATP plus ADP and acid hydrolases were studied. The metabolic inhibitors only affected 14C-labelled nucleotides, whereas thrombin only liberated unlabelled ATP and ADP. 3. The extent of secretion decreased progressively with time during incubation with the metabolic inhibitors. At any time the secretion of acid hydrolases, β-N-acetylglucosaminidase, β-glucuronidase and β-galactosidase was inhibited to a greater extent than secretion of ATP plus ADP (dense-granule secretion). 4. Incubation with the metabolic inhibitors shifted the log (dose)–response relationship to higher thrombin concentrations, and with a greater shift for acid hydrolase secretion than for dense-granule secretion. 5. Antimycin, when present alone, caused a marked decrease in the rate of acid hydrolase secretion, but had no effect on dense-granule secretion. 6. These results further support the view that acid hydrolase secretion and dense-granule secretion are separate processes with different requirements for ATP energy. Acid hydrolase secretion, but not dense-granule secretion, appears to depend on a simultaneous rapid generation of ATP, which can be accomplished by oxidative, but not by glycolytic, ATP production.

scholarly journals Transformation and motility of human platelets: details of the shape change and release reaction observed by optical and electron microscopy.

1979 ◽  
Vol 83 (1) ◽  
pp. 126-142 ◽  
Author(s):  
R D Allen ◽  
L R Zacharski ◽  
S T Widirstky ◽  
R Rosenstein ◽  
L M Zaitlin ◽  
...  
Keyword(s):  
Shape Change ◽  
Human Subjects ◽  
Blood Platelets ◽  
Time Lapse ◽  
Human Platelets ◽  
Transformation Process ◽  
Epifluorescence Microscopy ◽  
Scanning Electron Micrographs ◽  
Dense Bodies ◽  
Short Wavelength Light

Blood platelets from 10 normal human subjects have been examined with a sensitive differential interference contrast (DIC) microscope. The entire transformation process during adhesion to glass is clearly visible and has been recorded cinematographically, including the disk to sphere change of shape, the formation of sessile protuberances, the extension and retraction of pseudopodia, and the spreading, ruffling, and occasional regression of the hyalomere. The exocytosis of intact dense bodies can be observed either by DIC microscopy, or by epifluorescence microscopy in platelets stained with mepacrine. Details of fluorescent flashes indicate that the dense bodies usually release their contents extracellularly, may do so intracytoplasmically under the influence of strong, short wavelength light on some preparations of mepacrine-stained platelets. The release of one or more dense bodies leaves a crater of variable size on the upper surface of the granulomere. Such craters represent the surface component of the open canalicular system and their formation and disappearance can be directly observed. Because these techniques permit quantitation of several parameters of motility which are not readily observable by other techniques, it is suggested that high extinction DIC microscope examination may become a rapid and useful method of studying congenital and acquired platelet disorders. Many features of platelet transformation have been confirmed and extended by scanning electron micrographs. These can in turn be interpreted by reference to time-lapse films of living platelets.

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