scholarly journals Alterations in the diameter of erythrocytes during hæmolysis

1922 ◽  
Vol 94 (657) ◽  
pp. 102-108 ◽  
Keyword(s):  
Surface Tension ◽  
Cell Wall ◽  
Osmotic Pressure ◽  
Bile Salts ◽  
Sudden Change ◽  
Haemolytic Activity ◽  
Tension Stress ◽  
Red Cell ◽  
Chemical Action ◽  
Pressure Surface

There has been some doubt as to the manner in which certain substances produce hæmolysis, especially saponin, bile salts, and those hæmolysins which are the result of immunity experiments. The doubt has even been extended to the mode of action of hypotonic saline, the hæmolytic action of which is generally put down to the osmotic changes which it produces. Bechhold (1), however, considers that surface tension phenomena have much to do with this hæmolysis. As regards saponin, some observers consider that it destroys the cell wall (Arrhenius (2)), whereas others consider that it produces hæmolysis by lowering of surface tension; others, again, deny that there is any relation between surface tension and hæmolytic activity in the case of the saponins (Woodward and Alsberg (3)). The same doubt prevails regarding bile salts, it being considered by many that they dissolve the lipoid envelope, and by others that surface tension plays an important part. As regards hæmolysis by hæmolytic amboceptors, it is suggested by some that the action is due to a sudden change in the permeability of the envelope (Clowes (4)), and by others that the lipoids are attacked (Jobling and Bull (5)); or, again, that “osmotic pressure is altered” by the action of the hæmolysin (McDonagh (6)). Assuming what is generally admitted, that the red cell consists of an envelope containing a fluid or semi-fluid substance, some information may be gained by studying the changes of form which such a body would undergo under the various conditions of osmotic pressure, surface tension stress, or chemical action, and comparing with these the changes in form which may be observed in the red cell under the action of hæmolytic substances.

Colloid osmotic pressure changes of dog's blood exposed to different mixtures of CO2 and air

1978 ◽  
Vol 44 (2) ◽  
pp. 254-257 ◽  
Author(s):  
Y. Kakiuchi ◽  
A. B. DuBois ◽  
D. Gorenberg
Keyword(s):  
Red Blood Cells ◽  
Osmotic Pressure ◽  
Cell Volume ◽  
Blood Cells ◽  
Freezing Point ◽  
Colloid Osmotic Pressure ◽  
Red Cell ◽  
Freezing Point Depression ◽  
Pressure Changes ◽  
Different Levels

Hansen's membrane manometer method for measuring plasma colloid osmotic pressure was used to obtain the osmolality changes of dogs breathing different levels of CO2. Osmotic pressure was converted to osmolality by calibration of the manometer with saline and plasma, using freezing point depression osmometry. The addition of 10 vol% of CO2 to tonometered blood caused about a 2.0 mosmol/kg H2O increase of osmolality, or 1.2% increase of red blood cell volume. The swelling of the red blood cells was probably due to osmosis caused by Cl- exchanged for the HCO3- which was produced rapidly by carbonic anhydrase present in the red blood cells. The change in colloid osmotic pressure accompanying a change in co2 tension was measured on blood obtained from dogs breathing different CO2 mixtures. It was approximately 0.14 mosmol/kg H2O per Torr Pco2. The corresponding change in red cell volume could not be calculated from this because water can exchange between the plasma and tissues.

scholarly journals Photoprotection enhanced by red cell wall pigments in three East Antarctic mosses

2018 ◽  
Vol 51 (1) ◽  
Author(s):  
Melinda J. Waterman ◽  
Jessica Bramley-Alves ◽  
Rebecca E. Miller ◽  
Paul A. Keller ◽  
Sharon A. Robinson
Keyword(s):  
Cell Wall ◽  
Red Cell ◽  
Antarctic Mosses

The area and volume of single human erythrocytes during gradual osmotic swelling to hemolysis

1970 ◽  
Vol 48 (6) ◽  
pp. 369-376 ◽  
Author(s):  
Peter B. Canham ◽  
David R. Parkinson
Keyword(s):  
Osmotic Pressure ◽  
Single Cells ◽  
Ringer Solution ◽  
Potassium Ion ◽  
Distilled Water ◽  
Red Cell ◽  
Dialysis Membrane ◽  
Osmotic Swelling ◽  
Cell Changes ◽  
Area And Volume

A double-chambered slide was designed for the microscope which would enable continuous viewing of cells hanging on edge in a Ringer solution which was gradually being reduced in osmotic pressure. This was achieved by putting a dialysis membrane between the cell chamber and a chamber containing distilled water. Photographs were taken at 1-min intervals of single cells on edge (revealing the biconcave profile) until the cells hemolyzed, usually within 30 min. The area and volume of revolution of each cell were calculated from measurements on photographic enlargements. No significant change in area occurs during the swelling series although the red cell changes gradually from biconcave to spherical and remains spherical for approximately 7 min before hemolyzing. This stability is best explained by a leakage of potassium ion from the cell prior to hemolysis (which has been reported by Seeman to be approximately 20%).

Streptococci and enterococci

2020 ◽  
pp. 965-975
Author(s):  
Dennis L. Stevens ◽  
Sarah Hobdey
Keyword(s):  
Cell Wall ◽  
Genetic Analysis ◽  
Clinical Relevance ◽  
Domestic Animals ◽  
Clinical Disease ◽  
Haemolytic Activity ◽  
Diverse Group ◽  
Oral Streptococci ◽  
Infected Wounds ◽  
Cell Wall Carbohydrates

The term streptococcus was first used by Billroth in 1874 to describe chain-forming cocci found in infected wounds. The streptococci are a diverse group of Gram-positive pathogenic cocci that cause clinical disease in humans and domestic animals. They are traditionally classified on the basis of serological reactions, particularly Lancefield grouping based on cell-wall carbohydrates, and haemolytic activity on blood agar. Six groups can be defined by genetic analysis: pyogenic streptococci, milleri or anginosus group, mitis group, salivarius group, mutans group, and bovis group. Since the medically important members of the mitis, salivarius, and mutans groups are all oral streptococci and are of clinical relevance predominantly in endocarditis, they will be considered together in this chapter.

Partially miscible liquid systems: The density, change of volume on mixing, vapor pressure, surface tension, and viscosity in the system: aniline–hexane

1968 ◽  
Vol 46 (14) ◽  
pp. 2399-2407 ◽  
Author(s):  
A. N. Campbell ◽  
E. M. Kartzmark ◽  
S. C. Anand ◽  
Y. Cheng ◽  
H. P. Dzikowski ◽  
...  
Keyword(s):  
Surface Tension ◽  
Vapor Pressure ◽  
Chemical Potential ◽  
Density Change ◽  
Solution Temperature ◽  
Critical Solution Temperature ◽  
Pressure Surface ◽  
Anomalous Viscosity ◽  
Tension Properties ◽  
Liquid Systems

The following properties have been investigated experimentally: density, change of volume on mixing, vapor pressure, surface tension, and viscosity, at temperatures above and below the critical solution temperature. The question at issue is: How does the chemical potential, or any property dependent on chemical potential, change, at constant temperature, over a range of composition, just above the critical solution temperature? In the present case, the vapor pressure and surface tension, properties directly dependent on chemical potential, are constant within the range of experimental accuracy (which, however, may not be sufficient) over a range of concentration. The viscosity is complicated by the occurrence of anomalous viscosity. The change of volume on mixing is negative, and this is usually associated with compound formation. In all other systems investigated by us, except the system triethylamine–water, ΔV is positive. We have shown elsewhere, however, that a very stable chemical compound is formed between water and triethylamine.

scholarly journals Bacterial Swarming Reduces Proteus mirabilis and Vibrio parahaemolyticus Cell Stiffness and Increases β-Lactam Susceptibility

mBio ◽  
2019 ◽  
Vol 10 (5) ◽  
Author(s):  
George K. Auer ◽  
Piercen M. Oliver ◽  
Manohary Rajendram ◽  
Ti-Yu Lin ◽  
Qing Yao ◽  
...  
Keyword(s):  
Cell Wall ◽  
Osmotic Pressure ◽  
Proteus Mirabilis ◽  
Vibrio Parahaemolyticus ◽  
Cell Stiffness ◽  
Bending Rigidity ◽  
Vegetative Cells ◽  
Swarmer Cell ◽  
Content Type ◽  
Peptidoglycan Layer

ABSTRACT Swarmer cells of the Gram-negative uropathogenic bacteria Proteus mirabilis and Vibrio parahaemolyticus become long (>10 to 100 μm) and multinucleate during their growth and motility on polymer surfaces. We demonstrated that the increasing cell length is accompanied by a large increase in flexibility. Using a microfluidic assay to measure single-cell mechanics, we identified large differences in the swarmer cell stiffness (bending rigidity) of P. mirabilis (5.5 × 10−22 N m2) and V. parahaemolyticus (1.0 × 10−22 N m2) compared to vegetative cells (1.4 × 10−20 N m2 and 2.2 × 10−22 N m2, respectively). The reduction in bending rigidity (∼2-fold to ∼26-fold) was accompanied by a decrease in the average polysaccharide strand length of the peptidoglycan layer of the cell wall from 28 to 30 disaccharides to 19 to 22 disaccharides. Atomic force microscopy revealed a reduction in P. mirabilis peptidoglycan thickness from 1.5 nm (vegetative cells) to 1.0 nm (swarmer cells), and electron cryotomography indicated changes in swarmer cell wall morphology. P. mirabilis and V. parahaemolyticus swarmer cells became increasingly sensitive to osmotic pressure and susceptible to cell wall-modifying antibiotics (compared to vegetative cells)—they were ∼30% more likely to die after 3 h of treatment with MICs of the β-lactams cephalexin and penicillin G. The adaptive cost of “swarming” was offset by the increase in cell susceptibility to physical and chemical changes in their environment, thereby suggesting the development of new chemotherapies for bacteria that leverage swarming for the colonization of hosts and for survival. IMPORTANCE Proteus mirabilis and Vibrio parahaemolyticus are bacteria that infect humans. To adapt to environmental changes, these bacteria alter their cell morphology and move collectively to access new sources of nutrients in a process referred to as “swarming.” We found that changes in the composition and thickness of the peptidoglycan layer of the cell wall make swarmer cells of P. mirabilis and V. parahaemolyticus more flexible (i.e., reduce cell stiffness) and that they become more sensitive to osmotic pressure and cell wall-targeting antibiotics (e.g., β-lactams). These results highlight the importance of assessing the extracellular environment in determining antibiotic doses and the use of β-lactam antibiotics for treating infections caused by swarmer cells of P. mirabilis and V. parahaemolyticus.

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