scholarly journals MOVEMENTS OF WATER IN CELLS OF NITELLA

1949 ◽  
Vol 32 (4) ◽  
pp. 553-557 ◽  
Author(s):  
W. J. V. Osterhout
Keyword(s):  
Osmotic Pressure ◽  
The Other ◽  
In Cells

When one end of a Nitella cell (A) is bathed in water and a solution of sucrose is placed at the other (B) we find that water enters at A, travels along inside the cell, and escapes at B. The solutes which cannot pass out through the protoplasm at B remain behind so that the osmotic pressure increases at B and diminishes at A until equilibrium is reached and the motion stops. An equation is given which enables us to predict with considerable accuracy the amount of flow required to produce equilibrium.

scholarly journals TRANSPORT OF WATER FROM CONCENTRATED TO DILUTE SOLUTIONS IN CELLS OF NITELLA

1949 ◽  
Vol 32 (4) ◽  
pp. 559-566 ◽  
Author(s):  
W. J. V. Osterhout
Keyword(s):  
Osmotic Pressure ◽  
Living Cells ◽  
The Other ◽  
Fundamental Importance ◽  
Dilute Solution ◽  
Cell Water ◽  
Dilute Solutions ◽  
The Difference ◽  
In Cells

The transport of water from concentrated to dilute solutions which occurs in the kidney and in a variety of living cells presents a problem of fundamental importance. If the cell acts as an osmometer we may expect to bring about such transport by creating an inwardly directed osmotic drive which is higher in one part of the cell than in other regions of the same cell. The osmotic drive is defined as the difference between internal and external osmotic pressure. Experiments with Nitella show that this expectation is justified. If water is placed at one end of the cell (A) and 0.4 M sucrose with an osmotic pressure of 11.2 atmospheres at the other end (B) water enters at A, passes along inside the cell, and escapes at B leaving behind at B the solutes which cannot pass out through the protoplasm. Hence the internal osmotic pressure becomes much higher at B than at A. When 0.4 M sucrose at B is replaced by 0.3 M sucrose with an osmotic pressure of 8.1 atmospheres we find that water enters at B, passes along inside the cell, and escapes at A so that water is transported from a concentrated to a dilute solution although the difference in osmotic pressure of the 2 solutions is more than 8 atmospheres. The solution at B thus becomes more concentrated. It is evident that if metabolism produces a higher osmotic pressure and consequently a higher inwardly directed osmotic drive in one region of the cell as compared with other parts of the same cell water may be transferred from a concentrated to a dilute solution so that the former solution becomes still more concentrated.

scholarly journals Note on osmotic pressure

1914 ◽  
Vol 90 (615) ◽  
pp. 41-45
Keyword(s):  
Osmotic Pressure ◽  
Vapour Pressure ◽  
Numerical Data ◽  
The Other ◽  
Present Moment ◽  
Capillary Surface ◽  
Pure Solvent ◽  
Definition Of ◽  
Complete Account ◽  
Strict Definition

The vapour pressure theory regards osmotic pressure as the pressure required to produce equilibrium between the pure solvent and the solution. Pressure applied to a solution increases its internal vapour pressure. If the compressed solution be on one aide of a semi-permeable partition and the pure solvent on the other, there is osmotic equilibrium when the com-pression of the solution brings its vapour pressure to equality with that of the solvent. So long ago as 1894 Ramsay* found that with a partition of palladium, permeable to hydrogen but not to nitrogen, the hydrogen pressures on each side tended to equality, notwithstanding the presence of nitrogen under pressure on one side, which it might have been supposed would have resisted tin- transpiration of the hydrogen. The bearing of this experiment on the problem of osmotic pressure was recognised by van’t Hoff, who observes that "it is very instructive as regards the means by which osmotic pressure is produced." But it was not till 1908 that the vapour pressure theory of osmotic pressure was developed on a finu foundation by Calendar. He demonstrated, by the method of the "vapour sieve" piston, the proposition that “any two solutions in equilibrium through any kind of membrane or capillary surface must have the same vapour pressures in respect of each of their constituents which is capable of diffusing through their surface of separation"—a generalisation of great importance for the theory of solutions. Findlay, in his admirable monograph, gives a very complete account of the contending theories of osmotic pressure, a review of which leaves no doubt that at the present moment the vapour pressure theory stands without a serious rival Some confusion of ideas still arises from the want of adherence to a strict definition of osmotic pressure to which numerical data from experimental measurements should he reduced. Tire following definitions appear to be tire outcome of tire vapour pressure theory :— Definition I.—The vapour pressure of a solution is the pressure of the vapour with which it is in equilibrium when under pressure of its own vapour only.

scholarly journals OSMOTIC PRESSURE STUDY OF PROTEIN FRACTIONS IN NORMAL AND IN NEPHROTIC SUBJECTS

1939 ◽  
Vol 69 (6) ◽  
pp. 819-831 ◽  
Author(s):  
Jaques Bourdillon
Keyword(s):  
Osmotic Pressure ◽  
Normal Serum ◽  
The Other ◽  
Protein Fractions ◽  
Molecular Weights ◽  
Other Hand ◽  
Normal Albumin

In serum of patients with nephrosis both albumin and globulin showed by osmotic pressure nearly double the molecular weights of normal albumin and globulin. In the urines of such patients, on the other hand, both proteins showed molecular weights lower even than in normal serum. The colloidal osmotic pressures were measured by the author's method at such dilutions that the van't Hoff law relating pressures to molecular concentrations could be directly applied. For the albumin and globulin of normal serum the molecular weights found were 72,000 and 164,000 respectively, in agreement with the weights obtained by other methods.

scholarly journals Defective c-myc and c-myb RNA turnover in acute myeloid leukemia cells

Blood ◽  
1992 ◽  
Vol 79 (5) ◽  
pp. 1319-1326 ◽  
Author(s):  
MR Baer ◽  
P Augustinos ◽  
AJ Kinniburgh
Keyword(s):  
Acute Myeloid Leukemia ◽  
Posttranscriptional Regulation ◽  
Myeloid Leukemia ◽  
Actinomycin D ◽  
The Other ◽  
Rna Turnover ◽  
Gm Csf ◽  
Acute Myeloid Leukemia Cells ◽  
Acute Myeloid ◽  
In Cells

Dysregulated expression of the c-myc and c-myb protooncogenes has been implicated in the pathogenesis of acute myeloid leukemia (AML). To elucidate mechanisms of c-myc dysregulation in AML cells, we studied c- myc RNA turnover in peripheral blood blasts from eight patients using actinomycin D transcription blockade. Rapid c-myc RNA turnover was seen in cells from six patients, with half-lives of approximately 30 minutes, similar to those reported in normal myeloid cells, in HL-60 cells, and in other cell lines. c-myc RNA turnover was prolonged in cells of the other two patients, with half-lives of greater than 75 minutes. c-fos RNA turnover was rapid in blasts from all eight patients, with half-lives of approximately 15 minutes. Stabilization of GM-CSF transcripts was not observed. In contrast, c-myb RNA half-lives were greater than 75 minutes in cells of the two patients with prolonged c-myc RNA turnover, as compared to 30 minutes in cells of the other six patients. Enhanced stability of both c-myc and c-myb RNA species suggests that a defect exists in a trans-acting factor that destabilizes both of these normally labile RNAs. Incomplete correlation between c-myc RNA levels and half-lives indicates regulation of c-myc expression at the level of transcription or nuclear transport in addition to posttranscriptional regulation.

Fanconi Anemia: Prenatal Diagnosis in 30 Fetuses at Risk

PEDIATRICS ◽  
1985 ◽  
Vol 76 (5) ◽  
pp. 794-800
Author(s):  
Arleen D. Auerbach ◽  
Michal Sagi ◽  
Barbara Adler
Keyword(s):  
At Risk ◽  
Prenatal Diagnosis ◽  
Fanconi Anemia ◽  
Chorionic Villus ◽  
Chromosome Breakage ◽  
The Other ◽  
Chorionic Villus Sampling ◽  
Chromosomal Breakage ◽  
Born Infant ◽  
In Cells

We report our experience, since 1978, with prenatal diagnosis in fetuses at risk for Fanconi anemia. Amniotic fluid cells from 30 fetuses from 24 families were monitored for baseline and diepoxybutane-induced chromosomal breakage. Seven of the fetuses at risk were diagnosed as affected; baseline and diepoxybutane-induced breakage ranged from 0.18 to 0.45 and 0.69 to 0.96 breaks per cell, respectively. The range of baseline and diepoxybutane-induced chromosomal breakage in amniocytes from the 23 pregnancies at risk that were diagnosed prenatally as unaffected ranged from 0 to 0.08 and 0 to 0.13 breaks per cell, respectively. Four of these cases were also diagnosed as normal on the basis of chromosomal breakage studies in cells obtained by chorionic villus sampling. The range of baseline and diepoxybutane-induced breakage in cells from five control fetuses was 0 to 0.05 and 0 to 0.10 breaks per cell, respectively. Of the pregnancies diagnosed as affected, two were carried to term, whereas five were terminated. One newborn and two abortuses had congenital malformations including abnormalities of the thumb and radius. The other affected live-born infant, now 5½ years old, has severe growth retardation and pancytopenia. No Fanconi anemia-associated malformations were found in any of the other fetuses or newborns studied. In all cases in which tissue was available for study, diagnoses were confirmed by chromosome breakage studies. This method thus permits reliable detection of Fanconi anemia.

GERMINATION OF ALFALFA VARIETIES IN SOLUTIONS OF VARYING OSMOTIC PRESSURE AND RELATIONSHIP TO WINTER HARDINESS

1959 ◽  
Vol 39 (3) ◽  
pp. 384-394 ◽  
Author(s):  
D. H. Heinrichs
Keyword(s):  
Sodium Chloride ◽  
Osmotic Pressure ◽  
Laboratory Experiments ◽  
Reliable Method ◽  
Winter Hardiness ◽  
The Other ◽  
General Tendency ◽  
Salt Solutions ◽  
Sodium Chloride Solutions ◽  
Alfalfa Varieties

Two laboratory experiments were conducted to evaluate the reliability of amount of germination in solutions of varying osmotic pressure, as a means of separating alfalfa varieties into winter-hardiness classes. In one test 23 varieties or strains were studied, and in the other 36. It was found that significant differences exist between certain alfalfa varieties in their ability to germinate in sucrose or sodium chloride solutions of 3, 6, and 9 atmospheres. There is a general tendency for non-hardy varieties to germinate more rapidly and more completely than hardy ones but there are many exceptions to this trend. Germination in solutions of 6 atmospheres osmotic pressure at 5 days gave the best separation of varieties on the basis of their ability to germinate. Germination was generally better in solutions of sucrose at 6 atmospheres osmotic pressure than in solutions of sodium chloride of the same osmotic pressure but several varieties germinated equally well in either solution. The results indicate that germinating alfalfa in sugar or salt solutions is not a reliable method for differentiating alfalfa varieties into winter hardiness classes.

Mischkolonien auxotropher und Wildtypzellen nach Behandlung von Esdierichia coli-Zellen mit salpetriger Säure

1963 ◽  
Vol 18 (3) ◽  
pp. 245-252 ◽  
Author(s):  
F. Kaudewitz ◽  
K. Moebus ◽  
H. Kneser
Keyword(s):  
Experimental Evidence ◽  
Nitrous Acid ◽  
Single Cells ◽  
The Other ◽  
Mathematical Treatment ◽  
E Coli ◽  
Type 3 ◽  
Good Agreement ◽  
Hybrid Dna ◽  
In Cells

Cells of E. coli incubated in nitrous acid give rise 1. to unchanged wildtype colonies, 2. to colonies composed of wildtype and auxotrophic cells and 3. to colonies consisting of auxotrophic cells only. The mixed colonies are considered to originate from single cells each of them harbouring hybrid DNA with one subunit, probably a sisterstrand, changed by deamination of a cytosine or adenine, the other one with unchanged wildtype composition. In cells producing type 3 colonies this wildtype strand is mutated lethally by a separate deamination of a cytosine or adenine. A mathematical treatment of this hypothesis leads to predictions which are in good agreement with experimental evidence. The data obtained are used for an estimation of the number of gene-loci of E. coli.

scholarly journals Influence of Cystic Fibrosis Transmembrane Conductance Regulator on Gene Expression in Response to Pseudomonas aeruginosa Infection of Human Bronchial Epithelial Cells

2005 ◽  
Vol 73 (10) ◽  
pp. 6822-6830 ◽  
Author(s):  
Nina Reiniger ◽  
Jeffrey K. Ichikawa ◽  
Gerald B. Pier
Keyword(s):  
Cystic Fibrosis ◽  
Cell Line ◽  
Cell Lines ◽  
The Other ◽  
Transmembrane Conductance Regulator ◽  
Wild Type ◽  
Transmembrane Conductance ◽  
Bronchial Epithelial ◽  
Cystic Fibrosis Transmembrane ◽  
In Cells

ABSTRACT Chronic lung infection by Pseudomonas aeruginosa causes significant morbidity in cystic fibrosis patients initiated by the failure of innate immune responses. We used microarray analysis and real-time PCR to detect transcriptional changes associated with cytokine production in isogenic bronchial epithelial cell lines with either wild-type (WT) or mutant cystic fibrosis transmembrane conductance regulator (CFTR) in response to P. aeruginosa infection. The transcription of four NF-κB-regulated cytokine genes was maximal in the presence of WT CFTR: the interleukin-8 (IL-8), IL-6, CXCL1, and intracellular adhesion molecule 1 (ICAM-1) genes. Analysis of protein expression in two cell lines paired for wild-type and mutant CFTR with three P. aeruginosa strains showed IL-6 and IL-8 expressions were consistently enhanced by the presence of WT CFTR in both cell lines with all three strains of P. aeruginosa, although some strains gave small IL-8 increases in cells with mutant CFTR. CXCL1 production showed consistent enhancement in cells with WT CFTR using all three bacterial strains in one cell line, whereas in the other cell line, CXCL1 showed a significant increase in cells with either WT or mutant CFTR. ICAM-1 was unchanged at the protein level in one of the cell lines but did show mild enhancement with WT CFTR in the other cell pair. Inhibitions of NF-κB prior to infection indicated differing degrees of dependence on NF-κB for production of the cytokines, contingent on the cell line. Cytokine effectors of innate immunity to P. aeruginosa were found to be positively influenced by the presence of WT CFTR, indicating a role in resistance to P. aeruginosa infection.

scholarly journals Predominance of clathrin light chain LCb correlates with the presence of a regulated secretory pathway.

1990 ◽  
Vol 111 (4) ◽  
pp. 1419-1426 ◽  
Author(s):  
S L Acton ◽  
F M Brodsky
Keyword(s):  
Heavy Chain ◽  
Light Chain ◽  
Secretory Pathway ◽  
Expression Patterns ◽  
The Other ◽  
Light Chains ◽  
Total Light ◽  
Regulated Secretory Pathway ◽  
Preferential Incorporation ◽  
In Cells

Two forms of clathrin light chains, LCa and LCb, are expressed in all mammalian and avian tissues that have been examined, whereas only one type is found in yeast. Regions of structural dissimilarity between LCa and LCb indicate possible functional diversity. To determine how LCa and LCb might differentially influence clathrin function, light chain expression patterns and turnover were investigated. Relative expression levels of the two light chains were determined in cells and tissues with and without a regulated secretory pathway. LCa/LCb ratios ranged from 5:1 to 0.33:1. A higher proportion of LCb was observed in cells and tissues that maintain a regulated pathway of secretion, suggesting a specialized role for the LCb light chain in this process. The ratio of light chains in assembled clathrin was found to reflect the levels of total light chains expressed in the cell, indicating no preferential incorporation into triskelions or coated vesicles. The half-lives of LCa, LCb, and clathrin heavy chain were determined to be 24, 45, and 50 h, respectively. Thus, LCa is turned over independently of the other subunits. However, the half-lives of all three subunits are sufficiently long to allow triskelions to undergo many rounds of endocytosis, minimizing the possibility that turnover contributes to regulation of clathrin function. Rather, differential levels of LCa and LCb expression may influence tissue specific clathrin regulation, as suggested by the predominance of LCb in cells maintaining a regulated secretory pathway.

scholarly journals STUDIES IN EDEMA

1910 ◽  
Vol 12 (4) ◽  
pp. 487-509 ◽  
Author(s):  
Moyer S. Fleisher ◽  
Leo Loeb
Keyword(s):  
Sodium Chloride ◽  
Osmotic Pressure ◽  
Blood Vessels ◽  
Peritoneal Cavity ◽  
Peritoneal Fluid ◽  
Chloride Solution ◽  
Sodium Chloride Solution ◽  
The Other ◽  
Uranium Nitrate ◽  
Active Substances

1. In the experiments recorded in this paper the influence of the osmotic pressure of the blood upon absorption of fluid from the peritoneal cavity becomes apparent. Nephrectomy, removal of the adrenals, and other operations increase the osmotic pressure of the blood and increase the absorption of fluid from the peritoneal cavity. On the other hand, ether narcosis, at the period at which we tested its influence, causes neither an increase of osmotic pressure of the blood nor an increase in the absorption of fluid from the peritoneal cavity. 2. The increased osmotic pressure and increased absorption of fluid in nephrectomized animals is to a great extent not a specific effect of the removal of the kidneys, but approximately the same conditions can be observed after incisions of the skin and muscles. 3. After poisoning with uranium nitrate and in cases of peritonitis, complicating factors come into play, and under such conditions the absorption from the peritoneal cavity is not increased, notwithstanding the higher osmotic pressure of the blood. 4. In conditions in which the osmotic pressure of the blood is very high before the injection of sodium chloride solution into the peritoneal cavity (nephrectomized rabbits or rabbits injected with uranium nitrate three days previously), adrenalin causes no increase, or only a very slight one, in the absorption of peritoneal fluid. On the other hand, one day after the injection of uranium nitrate the osmotic pressure of the blood is only slightly increased before the injection of the sodium chloride solution into the peritoneal cavity, and here adrenalin causes a marked increase in absorption of fluid from the peritoneal cavity. 5. In animals injected with uranium nitrate the retention of sodium chloride and other osmotically active substances in the blood is not entirely due to interference with the functions of the kidney. This retention may be explained either by an inability of the tissues to bind the sodium chloride and other osmotically active substances or to a diminished permeability of the blood vessels for such substances. 6. While in nephrectornized animals the elimination of sodium chloride from the peritoneal cavity and also from the blood is increased, in animals injected with uranium nitrate such an elimination is diminished. This increase in the sodium chloride content of the peritoneal fluid in animals treated with uranium nitrate is accompanied by a decrease in the diffusion of other osmotically active substances into the peritoneal cavity. 7. While in nephrectomized animals and in animals injected with uranium nitrate one day previously, adrenalin causes a diminution of the fluid retained in the blood-vessels similar to the diminution noted in normal animals, adrenalin no longer exerts such an effect at a later stage of the uranium nitrate poisoning. At this period after the administration of uranium nitrate, the retention of fluid in the blood vessels is apparently equal in experiments with and without the injection of adrenalin, and following the absorption of fluid from the peritoneal cavity, the retention of fluid in the blood vessels in the uranium nitrate animals is increased comparatively to a greater extent than in normal animals. 8. Our experiments show a marked difference in the distribution of fluid and of osmotically active substances in nephrectomized animals and in animals injected with uranium nitrate. This difference may explain the much greater liability to the development of edema in animals injected with uranium nitrate.

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