Studies on dwarf larvae developed from isolated blastomeres of the starfish, Asterina pectinifera

Development ◽  
1978 ◽  
Vol 46 (1) ◽  
pp. 171-185
Author(s):  
Marina Dan-Sohkawa ◽  
Noriyuki Satoh
Keyword(s):  
Cell Volume ◽  
Larval Stage ◽  
Short Range ◽  
Total Cell ◽  
Cell Stage ◽  
Developmental System ◽  
Invertebrate Species ◽  
Total Cell Volume ◽  
Asterina Pectinifera

Not only a whole denuded egg, but also blastomeres isolated from 2-, 4- and 8-cell starfish embryos developed into morphologically normal, but dwarf bipinnariae, the sizes of which were roughly proportionate to that of the respective original blastomeres. Some of the blastomeres isolated from the 16-cell stage were also capable of developing into the larval stage. All isolated blastomeres divided in good synchrony with the control embryos. Blastulae of all groups gastrulated within quite a short range of time, around 14·5 h after insemination at 20±1 °C, although one-third of the 1/8-blastuIa missed this chance but gastrulated by 19·5 h. The number of constituent cells of the 1/8-gastrula was counted to be about 560, which corresponds roughly to one-half that of the 1/4-, one-fourth of the 1/2- and one-eighth of the 1/1-gastrula. This ratio also fitted roughly for the total cell volume. The results are compared with those of other invertebrate species, as well as of some vertebrates, and are discussed in connexion not only with the concepts of ‘regulative’ and ‘mosaic’ eggs, but also with a criterion that does not fit into either of these; the developmental system of the mammals.

Needle microepiphytes in a Douglas fir canopy: biomass and distribution patterns

1979 ◽  
Vol 57 (9) ◽  
pp. 1000-1007 ◽  
Author(s):  
George C. Carroll
Keyword(s):  
Cell Volume ◽  
Distribution Patterns ◽  
Douglas Fir ◽  
Total Cell ◽  
Microbial Cell ◽  
Microbial Cells ◽  
Cutting Out ◽  
Total Cell Volume ◽  
Volume Estimates ◽  
Cell Volumes

Distribution patterns and total cell-volume estimates for needle microepiphytes are presented for three strata in the canopy of a single old-growth Douglas fir tree. Microbial cell volume was estimated by photographing transverse sections of needles, tracing microbial profiles on Mylar film, cutting out the tracings, and determining the pooled trace weights from various zones of each needle section. Microbial cells are concentrated in the midrib groove and over the stomatal zones of individual needles. Microbial cell volume on the upper needle surfaces increases during the 1st year and declines in subsequent years. Cell volumes on the lower needle surfaces increase from the 1st to the 3rd year and decrease from the 3rd to the 4th year. An increase in microbial cell volume occurs on both upper and lower surfaces from year 7 to year 8. Total microbial cell volume in relation to available needle surface area is greatest in the lower canopy and decreases with increasing height in the canopy. The total volume of microbial cells on needles was estimated to be 1093 cm3 for the entire tree.

scholarly journals Cellular dimensions affecting the nucleocytoplasmic volume ratio.

1991 ◽  
Vol 115 (4) ◽  
pp. 941-948 ◽  
Author(s):  
J A Swanson ◽  
M Lee ◽  
P E Knapp
Keyword(s):  
Endothelial Cells ◽  
Cell Volume ◽  
Volume Ratio ◽  
Fluorescein Isothiocyanate ◽  
Total Cell ◽  
Nuclear Volume ◽  
Size Exclusion ◽  
Nuclear Surface ◽  
Murine Bone Marrow ◽  
Total Cell Volume

Although it has long been appreciated that larger eukaryotic cells have larger nuclei, little is known about how this size relationship is maintained. Here we describe a method for measuring the aqueous volume ratio of nucleus to cytoplasm, two compartments which are interconnected via the pores in the nuclear envelope. We then use that method to identify proportional cellular dimensions in variously treated cells and in different cell types. Cells were scrape loaded with a mixture of fluorescent dextrans: Texas red dextran, average mol wt = 10,000 (TRDx10), and fluorescein isothiocyanate dextran, average mol wt = 70,000 (FDx70). After introduction into the cytoplasmic space, the TRDx10 distributed into both the nucleus and cytoplasm, whereas the FDx70 was restricted to cytoplasm, due to size exclusion by the nuclear pores. The aqueous nucleocytoplasmic volume ratio (RN/C) was determined by measuring, from fluorescence images of spread cells, total cellular fluorescence of each of the two probes and the fluorescence ratio of those probes in the cytoplasm. RN/C was unaffected by the measurement procedure or by varying temperatures between 23 degrees and 37 degrees C. Loading excess unlabeled dextrans had little effect on RN/C, with the single exception that high concentrations of large dextrans could lower RN/C in endothelial cells. Expanding intracellular membranous compartments of macrophages by phagocytosis of latex beads decreased RN/C. Expanding the same compartment by pinocytosis of sucrose, which nearly doubled total cell volume, had little effect on RN/C, indicating that nuclear volume was more closely linked to the cytoplasmic volume, exclusive of vesicular organelles, than to total cell volume. RN/C was the same in mononucleate and binucleate endothelial cells. Finally, measurements of RN/C in murine bone marrow-derived macrophages, bovine aortic endothelial cells, Swiss 3T3 fibroblasts, PtK2 cells, and CV-1 cells revealed that nuclear volume scaled allometrically with cell volume. The allometric relationship indicated that cell volume was proportional to nuclear surface area.

scholarly journals BLOOD DESTRUCTION DURING EXERCISE

1922 ◽  
Vol 36 (5) ◽  
pp. 481-500 ◽  
Author(s):  
G. O. Broun
Keyword(s):  
Cell Volume ◽  
Plasma Volume ◽  
Peripheral Blood ◽  
Prolonged Exercise ◽  
Jugular Vein ◽  
Total Cell ◽  
Total Cell Volume

The following changes have been demonstrated to take place in the blood of dogs during exercise. 1. An increase in the per cent of cells and hemoglobin in the blood of the jugular vein occurs early in the course of exercise. It probably results from a redistribution of red corpuscles, with an increase in their proportion in the peripheral blood. 2. As exercise is continued, there is a definite increase in plasma volume. 3. A coincident decrease both in the total cell volume and the pigment volume during prolonged exercise suggests that blood destruction then occurs.

Three-dimensional reconstruction of organelles in Euglena gracilis Z. I. Qualitative and quantitative changes of chloroplasts and mitochondrial reticulum in synchronous photoautotrophic culture

1980 ◽  
Vol 43 (1) ◽  
pp. 137-166
Author(s):  
M. Pellegrini
Keyword(s):  
Cell Cycle ◽  
Cell Volume ◽  
Growth Phase ◽  
Euglena Gracilis ◽  
Light And Electron Microscopy ◽  
Total Cell ◽  
Ultrastructural Changes ◽  
Total Cell Volume ◽  
Euglena Gracilis Z ◽  
Mitochondrial Reticulum

Ultrastructural changes of chloroplasts and mitochondria have been observed in synchronously growing cells of Euglena gracilis Z, under photoautotrophic conditions. Application of the serial section technique allows estimation of the number and volume of these organelles. Several 3-dimensional reconstructions reveal their shape and distribution throughout the cell cycle. In young cells 10 separate diskoid or branched chloroplasts are found. They show the typical lamellar structure of euglenoid chloroplasts. During the growth phase (light period), they enlarge and their volume doubles. Some of them branch out, so that 20 lobes are formed. Thylakoids grow longer without change in number. The pyrenoid persists only during the first half of this period. During the cell division phase (dark period), branched chloroplasts divide along 2 planes which are perpendicular to each other and perpendicular to the thylakoid plane. All thylakoids are cut and their number does not change in the daughter chloroplasts. The plastidome volume constitutes 15–18% of the total cell volume over the entire life cycle. One of the most significant observations in this report is the presence of a single permanent mitochondrial reticulum during the whole cell cycle. This giant mitochondrion consists of an extremely branched network with delicate threads (0.4-0.6 micrometer thick) surrounding the chloroplasts, nucleus and reservoir. It extends throughout the cell. During the growth phase, it becomes gradually longer and doubles in volume. The degree of branching increases but the thickness of the threads remains constant. During the division phase, the mitochondrial elements appear more restricted (0.4 micrometer thick) and the reticulum becomes progressively partitioned into 2 daughter networks. At any time of the cell cycle, the chondriome volume is about 6% of the total cell volume. These results are discussed in comparison with numerous relevant papers on light and electron microscopy of animal and plant cells. They suggest that the descriptions of several authors on the plastidial cycle and the mitochondrial cycle in Euglena, both said to be characterized by alternate reticulate and fragmentary states, arise in part from questionable interpretation of random sections. It is evident that the form and distribution of organelles can be determined more precisely by serial sectioning.

scholarly journals THE CHANGE IN OSMOTICALLY INACTIVE FRACTION PRODUCED BY CELL ACTIVATION

1948 ◽  
Vol 32 (1) ◽  
pp. 43-51 ◽  
Author(s):  
Herbert Shapiro
Keyword(s):  
Cell Volume ◽  
Sea Urchin ◽  
Cell Activation ◽  
Sea Water ◽  
Total Cell ◽  
Respiratory Metabolism ◽  
Arbacia Punctulata ◽  
Mechanical Analogue ◽  
Total Cell Volume ◽  
Cell Volumes

1. Resting and activated eggs of the sea urchin Arbacia punctulata were swollen in hypotonic sea water (60, 70, 80, and 90 per cent), and allowed to attain equilibrium volumes (Figs. 1 and 2). 2. Both fertilized and unfertilized eggs obey the Boyle-van't-Hoff law, but the value for b, the "osmotically inactive fraction" or non-swellable volume, was different for the two, averaging in the cases studied 7.3 per cent for unfertilized and 27.4 per cent for fertilized. 3. On activation, the eggs of the sea urchin undergo a definite increase in total cell volume, of approximately 2.7 per cent. 4. Some evidence is adduced for the possibility that the alteration in cell volume and in o.i.f. may depend upon the species in question. 5. A parallelism between change in b and alteration of respiratory metabolism in Arbacia, Chaetopterus, and Arbacia fragments is pointed out. This requires further investigation in other species to establish generality. 6. Equations for the calculation of the point at which osmotic pressures and cell volumes are identical for unfertilized and fertilized eggs are included. 7. A mechanical analogue of the phenomena is introduced (Fig. 3).

P1054COMBINING A HEPARIN-GRAFTED DIALYZER WITH A CITRATE ENRICHED DIALYSATE OFFERS ADEQUATE HEMODIALYSIS EFFICACY AVOIDING SYSTEMIC ANTICOAGULATION: RESULTS OF THE NON-INFERIORITY RANDOMIZED EVOCIT STUDY

2020 ◽  
Vol 35 (Supplement_3) ◽  
Author(s):  
Karlien François ◽  
Dieter De Clerck ◽  
Annelies Tonnelier ◽  
Marie-Laure Cambier ◽  
Wilfried Cools ◽  
...  
Keyword(s):  
Cell Volume ◽  
Treatment Time ◽  
Reduction Rate ◽  
Low Frequency ◽  
Total Cell ◽  
Maintenance Hemodialysis ◽  
Dialysate Flow ◽  
Total Cell Volume ◽  
Systemic Anticoagulation ◽  
The Difference

Abstract Background and Aims The combined use of a heparin-grafted membrane with a citrate enriched dialysate is an effective hemodialysis strategy with low circuit clotting rates while avoiding systemic anticoagulation. Whether this technique results in dialysis efficacy that is non-inferior to regular hemodialysis using systemic anticoagulation has not been investigated up to now. Method Prevalent hemodialysis (n=26) patients were recruited for a randomized crossover non-inferiority trial powered at >90% to detect a prespecified non-inferiority threshold of 10% spKt/Vurea (NCT03887468). Hemodialysis using a heparin-grafted dialyzer in combination with a 1.0 mmol/L citrate enriched dialysate (“evocit”) was compared to hemodialysis using a heparin-grafted dialyzer, systemic unfractionated heparin and regular bicarbonate-based dialysate (“evohep”). Each treatment arm lasted 4 weeks with a 3x4hours weekly hemodialysis regimen. All sessions were standardized with fixed blood- and dialysate flow rates. Biological analyses were done during midweek sessions. The primary endpoint was spKt/Vurea. Secondary endpoints included alternative adequacy markers, premature treatment termination, retransfusion failure and loss of total cell volume of the dialyzer after dialysis. Results A total of 617 hemodialysis sessions were performed: 307 sessions according to evocit and 310 sessions according to evohep protocol. Mean spKt/Vurea was 1.45±0.25 for evocit sessions and 1.50±0.26 for evohep sessions. In a paired analysis, mean of the difference in spKt/Vurea between both study arms was 0.05 with a 95%CI of 0.012-0.098 (p=0.01), the upper bound of the estimate lying within the prespecified non-inferiority threshold (i.e. <0.15). Processed blood volume was 75.4±3L vs 75.8±1.5L and online Kt was 47.3±5L vs 48.3±4L for all evocit and evohep sessions respectively. Urea reduction rate (RR) was 71.3±5.7 vs 72.3±5.8, bèta2microglobulin RR 37.1±8 vs 37.9±8 and myoglobin RR 30.9±9.8 vs 34.5±12.5 for midweek evocit and evohep sessions respectively. Circuit thrombosis leading to premature treatment end occurred in 13/307 (4.23%) of evocit sessions in 6/26 patients but in none of the evohep sessions (p=0.03). Treatment time of evocit sessions complicated with circuit thrombosis (n=13) was reduced with 36 minutes (IQR 20-46 minutes) without impact on effective treatment times overall (236±12 vs 238±4 minutes for evocit and evohep sessions respectively). Retransfusion failure occurred in 3/307 (0.98%) of evocit sessions and none of the evohep sessions. Dialyzers’ total cell volume was reduced with 17% (IQR 11-33%) and 9% (IQR 6-17%) (p<0.0001) after evocit and evohep sessions respectively. Conclusion Hemodialysis avoiding systemic anticoagulation using a heparin-grafted dialyzer with a citrate enriched dialysate is an adequate technique for maintenance hemodialysis offering spKt/Vurea results within recommended dose, and is not inferior to standard hemodialysis using systemic anticoagulation with heparin in terms of spKt/Vurea. Circuit clotting complications occurred at low frequency during evocit sessions and did not have clinically significant repercussions on dialysis efficacy.

Mitochondria of Tetrahymena pyriformis: enumeration and sizing of isolated organelles using a Coulter Counter and pulse-height analyser

1983 ◽  
Vol 61 (1) ◽  
pp. 437-451
Author(s):  
R.K. Poole
Keyword(s):  
Cell Volume ◽  
Pulse Height ◽  
Tetrahymena Pyriformis ◽  
Mitochondrial Fraction ◽  
Single Step ◽  
Total Cell ◽  
Coulter Counter ◽  
Intact Cells ◽  
Pulse Height Analyser ◽  
Total Cell Volume

An electronic particle counter (Coulter Counter ZBI) and pulse-height analyser (Channelyzer C1000) have been used to measure numbers and sizes of mitochondria isolated from the ciliated protozoon Tetrahymena pyriformis. Differential centrifugation of disrupted organisms, followed by single-step sub-fractionation of the mitochondrial fraction on sucrose gradients yielded a population of organelles extensively enriched in the activities of mitochondrial marker enzymes. Gradient-purified mitochondria (approx. 3 X 10(9) particles (mg protein)-1) were stable in electrolyte, exhibited unimodal volume distributions and were somewhat larger (0.93 +/− 0.13 (S.D.) microns 3; 19 preparations) than organelles in a crude mitochondrial fraction. Glutaraldehyde fixation of mitochondria in sucrose gradients decreased the apparent volume to 0.6 +/− 0.06 micron 3 (6 preparations). Based on the recovery in the mitochondrial fraction of mitochondrial membrane-bound cytochromes from a suspension of intact cells, the number of mitochondria per cell was estimated to be approximately 1440, representing 15% of the total cell volume. Isolated mitochondria were osmotically sensitive and exhibited an apparent marked contraction on adding Ca2+ (10 microM-10mM). Addition of chloramphenicol (500 micrograms ml-1) to exponentially growing Tetrahymena cultures resulted in an almost immediate cessation of cell division and a dramatic decrease in cell volume. Mitochondria purified from such cells were much smaller than control mitochondria (0.21 +/− 0.02 microns 3; 7 measurements); their population density was approximately 900 per cell, equivalent to 11% of total cell volume. The measurements of mitochondrial populations using the Coulter Counter and electron microscopy are in good agreement.

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