Co-infections with hepatitis G and TT virus in patients with chronic hepatitis C in Hungary

The significance of co-infections with novel hepatitis viruses Hepatitis G (GBV-C, HGV) and TT virus (TTV) in chronic hepatitis C is not clear. We determined the prevalence of HGV RNA and TTV DNA in chronic hepatitis C patients and in asymptomatic hepatitis C virus (HCV) carriers, and assessed the influence of these agents on the course of HCV infection. Seventy-seven patients with chronic hepatitis C--50 of them treated with interferon (IFN)--and 33 HCV carriers with normal alanine aminotransferase have been investigated. Previous HBV infection was detected by testing serum HBsAg and aHBc. HGV RNA and TTV DNA were detected by PCR. In the healthy population, the prevalence of anti-HCV was 0.3%, HGV RNA 8.0% and TTV DNA 18.5%. In chronic hepatitis C HGV RNA occurred in 9.09% and TTV DNA in 40.25% of cases. In IFN-treated patients with sustained remission, the frequency of TTV was 20% vs. 45.7% found in non-responders. Among asymptomatic HCV-carriers, the prevalence of HGV RNA was 9.09% and TTV DNA 75.7%. Neither HGV RNA nor TTV DNA had apparent effect on the HCV infection. TTV was detected with the lowest frequency in persons with sustained remission due to IFN, suggesting antiviral effect of IFN on TTV.

[Plasma electrolytes in multiple myeloma]

The plasma cell myeloma (multiple myeloma, myelomatosis) is a progressive disease, characterized by bone marrow plasmacytomas and the presence of monoclonal antibodies (IgG, IgA, IgD, IgE), or free kappa or lambda immunoglobulin side chains. The monoclonal antibodies or Bence-Jones protein may precipitate in the tubuli and impair kidney function. In addition, the plasma protein concentration may increase at the expense of plasma water level causing unrealistically low electrolyte levels. Since the isoelectric points of immunoglobulins are higher than those of most other plasma proteins, the net charge of plasma proteins may change causing new electrolyte balance. In addition, some monoclonal antibodies are more hydrated than others, and their high concentration may cause not only increased plasma viscosity but further electrolyte imbalance. In the present work the relationship between plasma protein and electrolyte levels is studied in samples of 100 multiple myeloma patients.

Identification of the NAD(+)-binding fold of glyceraldehyde-3-phosphate dehydrogenase as a novel RNA-binding domain

There is growing evidence that metabolic enzymes may act as multifunctional proteins performing diverse roles in cellular metabolism. Among these functions are the RNA-binding activities of NAD(+)-dependent dehydrogenases. Previously, we have characterized the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH) as an RNA-binding protein with preference to adenine-uracil-rich sequences. In this study, we used GST-GAPDH fusion proteins generated by deletion mutagenesis to search for the RNA binding domain. We established that the N-terminal 43 amino acid residues of GAPDH, which correspond to the first mononucleotide-binding domain of the NAD(+)-binding fold is sufficient to confer RNA-binding. We also provide evidence that this single domain, although it retains most of the RNA-binding activity, loses sequence specificity. Our results suggest a molecular basis for RNA-recognition by NAD(+)-dependent dehydrogenases and (di)nucleotide-binding metabolic enzymes that had been reported to have RNA-binding activity with different specificity. To support this prediction we also identified other members of the family of NAD(+)-dependent dehydrogenases with no previous history of nucleic acid binding as RNA binding proteins in vitro. Based on our findings we propose the addition of the NAD(+)-binding domain to the list of RNA binding domains/motifs.

Relationship between the occurrence of cysteine in proteins and the complexity of organisms

The occurrence and relative positions of cysteine residues were investigated in proteins of various species. Considering random mathematical occurrence for an amino acid coded by two codons (3. 28%), cysteine is underrepresented in all organisms investigated. Representation of cysteine appears to correlate positively with the complexity of the organism, ranging between 2.26% in mammals and 0. 5% in some members of the Archeabacteria order. This observation, together with the results obtained from comparison of cysteine content of various ribosomal proteins, indicates that evolution takes advantage of increased use of cysteine residues. In all organisms studied except plants, two cysteines are frequently found two amino acid residues apart (C-(X)(2)-C motif). Such a motif is known to be present in a variety of metal-binding proteins and oxidoreductases. Remarkably, more than 21% of all of cysteines were found within the C-(X)(2)-C motifs in ARCHEA.: This observation may indicate that cysteine appeared in ancient metal-binding proteins first and was introduced into other proteins later.

Loss of the major isoform of phosphoglucomutase results in altered calcium homeostasis in Saccharomyces cerevisiae

Phosphoglucomutase (PGM) is a key enzyme in glucose metabolism, where it catalyzes the interconversion of glucose 1-phosphate (Glc-1-P) and glucose 6-phosphate (Glc-6-P). In this study, we make the novel observation that PGM is also involved in the regulation of cellular Ca(2+) homeostasis in Saccharomyces cerevisiae. When a strain lacking the major isoform of PGM (pgm2Delta) was grown on media containing galactose as sole carbon source, its rate of Ca(2+) uptake was 5-fold higher than an isogenic wild-type strain. This increased rate of Ca(2+) uptake resulted in a 9-fold increase in the steady-state total cellular Ca(2+) level. The fraction of cellular Ca(2+) located in the exchangeable pool in the pgm2Delta strain was found to be as large as the exchangeable fraction observed in wild-type cells, suggesting that the depletion of Golgi Ca(2+) stores is not responsible for the increased rate of Ca(2+) uptake. We also found that growth of the pgm2Delta strain on galactose media is inhibited by 10 microM cyclosporin A, suggesting that activation of the calmodulin/calcineurin signaling pathway is required to activate the Ca(2+) transporters that sequester the increased cytosolic Ca(2+) load caused by this high rate of Ca(2+) uptake. We propose that these Ca(2+)-related alterations are attributable to a reduced metabolic flux between Glc-1-P and Glc-6-P due to a limitation of PGM enzymatic activity in the pgm2Delta strain. Consistent with this hypothesis, we found that this "metabolic bottleneck" resulted in an 8-fold increase in the Glc-1-P level compared with the wild-type strain, while the Glc-6-P and ATP levels were normal. These results suggest that Glc-1-P (or a related metabolite) may participate in the control of Ca(2+) uptake from the environment.

The vacuolar Ca2+/H+ exchanger Vcx1p/Hum1p tightly controls cytosolic Ca2+ levels in S. cerevisiae

It is well established that the vacuole plays an important role in the cellular adaptation to growth in the presence of elevated extracellular Ca2+ concentrations in Saccharomyces cerevisiae. The Ca2+ ATPase Pmc1p and the Ca2+/H+ exchanger Vcx1p/Hum1p have been shown to facilitate Ca2+ sequestration into the vacuole. However, the distinct physiological roles of these two vacuolar Ca2+ transporters remain uncertain. Here we show that Vcx1p can rapidly sequester a sudden pulse of cytosolic Ca2+ into the vacuole, while Pmc1p carries out this function much less efficiently. This finding is consistent with the postulated role of Vcx1p as a high capacity, low affinity Ca2+ transporter and suggests that Vcx1p may act to attenuate the propagation of Ca2+ signals in this organism.

The Golgi apparatus plays a significant role in the maintenance of Ca2+ homeostasis in the vps33Delta vacuolar biogenesis mutant of Saccharomyces cerevisiae

The vacuole is the major site of intracellular Ca2+ storage in yeast and functions to maintain cytosolic Ca2+ levels within a narrow physiological range. In this study, we examined how cellular Ca2+ homeostasis is maintained in a vps33Delta vacuolar biogenesis mutant. We found that growth of the vps33Delta strain was sensitive to high or low extracellular Ca2+. This strain could not properly regulate cytosolic Ca2+ levels and was able to retain only a small fraction of its total cellular Ca2+ in a nonexchangeable intracellular pool. Surprisingly, the vps33Delta strain contained more total cellular Ca2+ than the wild type strain. Because most cellular Ca2+ is normally found within the vacuole, this suggested that other intracellular compartments compensated for the reduced capacity to store Ca2+ within the vacuole of this strain. To test this hypothesis, we examined the contribution of the Golgi-localized Ca2+ ATPase Pmr1p in the maintenance of cellular Ca2+ homeostasis. We found that a vps33Delta/pmr1Delta strain was hypersensitive to high extracellular Ca2+. In addition, certain combinations of mutations effecting both vacuolar and Golgi Ca2+ transport resulted in synthetic lethality. These results indicate that the Golgi apparatus plays a significant role in maintaining Ca2+ homeostasis when vacuolar biogenesis is compromised.

Augmented water binding and low cellular water content in erythrocytes of camel and camelids

We investigated a link between hemoglobin primary structure, hemoglobin hydrophobicity-hydrophilicity, and erythrocyte water content in various mammalian species. Some hemoglobin molecules, particularly those of the camel and camelids, contain more charged amino acid residues and are more hydrophilic than the hemoglobins of human and a number of other mammalian species. To test the in vivo significance of these alterations of hemoglobin primary structure, we determined the osmotically unresponsive erythrocyte water fractions in mannit solutions of various osmolarities at 4 degreesC. Among the species investigated, the size of the osmotically unresponsive erythrocyte water fraction relates in a positive linear way to hemoglobin hydrophilicity. The extreme low total erythrocyte water content of camel erythrocytes (1.1-1.3 g water/g dry mass) may be explained by a comparatively high osmotically unresponsive erythrocyte water fraction. It is proposed that alterations of hemoglobin sequences of camel and camelids may be the part of a natural selection process aimed at protecting these animals against osmotic dehydration in arid environments.

On the role of Na,K-ATPase: a challenge for the membrane-pump and association-induction hypotheses

The regulation of cellular ion levels has been an important issue of cell physiology since the beginning of the century. A special interest was focused on the monovalent ions which are involved in several cellular functions; in fact, the maintenance of high K+ level inside the cells is one of the most basic life-phenomena. Regarding the regulation of monovalent ions in general, two opposing ideas emerged: one being the membrane theory and the other the sorption theory(ies). Today most scientists are familiar only with the membrane theory which involves the pump and leak hypothesis and only a few consider the predictions of the association-induction hypothesis which may be classified as one of the sorption theories. In the regulation of monovalent ions the Na,K-ATPase is a key-molecule according to the membrane theory but not considered that important by the association-induction hypothesis. In this paper, we present two simple experiments which demonstrate the possible role of this molecule in the regulation of cellular Na+, K+ homeostasis and also disprove the pump and leak hypothesis.

Chirality differences in amino acid retention and release from acid-extractable pool of cultured mammalian cells

In previous work, no chiral differences were found between D and L enantiomers of Leu in their ability to displace one another from the acid-extractable pool in mammalian cells. Recent evidence suggested otherwise. Our aim is to examine whether, in physiological range, D-amino acids have an equivalent ability to displace L-amino acids from the acid-extractable pool of HeLa cells, and vice versa. In the Millimolar range, D-Leu and L-Leu have similar uptake and displacement properties with regard to the acid-extractable pool in HeLa cells, despite only the latter isomer being incorporated into protein. Below millimolar concentration however, a distinct difference was found in the displacement of tritium-labelled L-Leu from the pool by unlabelled D-Leu compared with unlabelled L-Leu. Thus, unlabelled L-Leu in the external medium at 10(-4) or 10(-5) M displaced and equivalent amount of label from the pool ad D-Leu introduced at a concentration approx. one order of magnitude higher, respectively. Reciprocal experiments, in which the acid-extractable pool was preloaded with 3H-D-Leu, confirmed this finding. The chirality difference was noted whether pool prelabelling was carried out at 37 or 0 degrees C; but in order to avoid the complications of active transport mechanisms, the competition work reported here was done at 0 degrees C. Similar chirality differences were observed with other hydrophobic amino acids, including His, Ile, and Phe, such as, preferential displacement by the L-Leu racemer compared with the D-Leu racemer below mM levels. This was also true for the D and L forms of the non-utilisable isomer of Leu, norleucine (nLeu). We conclude that D-forms of hydrophobic amino acids have lower affinity for similar or the same intracellular binding sites involved in the acid-extractable pool than in their L-forms. The significance of these findings to amino acid pools in cells, and to the predominance of L-forms of amino acids in the biosphere is considered

Albumin can reverse the release of potassium from human erythrocytes treated with the non-ionic detergent, Brij 58

Exchange of erythrocyte intracellular (i/c) K+ for extracellular (e/c) Na+ in human erythrocytes treated with sub-CMC concentrations of the non-ionic detergent Brij 58 can be stopped by reincubation in serum or albumin containing solutions. The progressive equilibration of the K+ contents of detergent-treated human erythrocytes with the incubation medium was reversed by an albumin-mediated withdrawal of detergent molecules from the cell. Re-establishment of near normal [K+] in terms of K+/kg water proceeds in two ways: (i) a metabolism-dependent net accumulation of K+ ions; and (ii) a metabolism-independent shrinkage of erythrocytes, this being the more significant factor.

Maintenance of ions, proteins and water in lens fiber cells before and after treatment with non-ionic detergents

If the plasma membrane and its associated transport proteins are solely responsible for maintenance of the asymmetric solute distribution then disruption of the plasma membrane would quickly lead to the symmetric distribution of all unattached inorganic ions between the cell and the extracellular environment. To test this hypothesis fresh pig lenses were incubated in Hanks' balanced salt solution in either absence or presence of non-ionic detergents (0.2% Triton X-100 or 0.2% Brij 58). Both detergents caused permeabilization of every lens fiber cell as shown by electron microscopy. The flux kinetics of K+, Mg2+, Na+, Ca2+, water and protein out of and into the permeabilized lens fiber cells was measured. Triton X-100 caused a faster flux rate of all solutes than did Brij 58. The Triton X-100 induced flux of solutes and water was associated with a decrease in lens ATP. Incubation of untreated lenses in solutions of different osmotic pressures at 0 degree C demonstrated that the major fraction of lens water was osmotically unresponsive. Thus the asymmetric distribution of solutes in lens fiber cells is dependent on an intact plasma membrane and on a co-operative ATP-dependent association between K+, Mg2+, water and cytomatrix proteins.

Phenylalanine utilization for protein synthesis in beta-phenylpyruvic acid treated Escherichia coli cells

The possibility of coupling along the supply routes of phenylalanine from its uptake by the cell, through the charging of specific tRNAs, has been postulated. The experimental approach to testing this hypothesis has been to study the competition between endogenously synthesized and exogenously supplied amino acids, from which preferences for their incorporation into cellular proteins can be deduced. The results indicate that manipulation of the endogenous phenylalanine pool size, achieved by addition of its immediate precursor, beta-phenylpyruvate, does not cause the predicted changes in the incorporation of exogenous labelled phenylalanine into proteins. The evidence favours exogenous phenylalanine being preferentially delivered to the sites of protein synthesis.

Nuclear magnetic resonance relaxation parameters of muscle in malignant hyperthermia-susceptible swine

RATIONALE AND OBJECTIVES

The malignant hyperthermia (MH) syndrome involves characteristic changes in metabolism that have a significant effect on the postmortem properties of muscle tissue. We investigated the 1H nuclear magnetic resonance (MR) relaxation parameters of muscle tissue from normal (MH-) and malignant hyperthermia-susceptible (MH+) swine taken before their death to identify whether postmortem metabolic differences would be accompanied by changes in relaxation parameters.

METHODS

Muscle samples from 63 MH-susceptible swine were characterized by proton MR relaxation times (T1 and T2). The water content, pH, conducting, and the "subjective meat" quality were assessed in order to differentiate the meat into one of three groups: normal, pale-soft-exudative, and dark-firm-dry.

RESULTS

The T2 relaxation of MH- and MH+ muscles was significantly different, but no significant changes were detected in the water content and corresponding T1 relaxation times.

CONCLUSION

These data suggest that MH-susceptible swine can be distinguished from normal swine using nuclear MR relaxometry. The results of relaxation measurements and the multiexponential analysis of the T2 curves suggest a shift between the different water compartments during MH that might predict the increased water loss of muscle tissue after death.

Effect of non-lytic concentrations of Brij series detergents on the metabolism-independent ion permeability properties of human erythrocytes

Subcritical micellar concentrations (sub-CMC) of Brij-series detergents alter ion movements between human erythrocytes and their environment when metabolism has been slowed down by incubation at zero degrees centigrade. The effect of nonhemolytic concentrations of detergents on the erythrocyte K+ and Na+ movements is described. Results indicate a significant difference in monovalent cation movements, depending on the number of hydrophilic polyoxyethylene units (n). There is an increasing loss of K+ and gain of Na+ as n increases from 4 to 20. Where n > or = 21, ion movements are not significantly different from those found in erythrocytes not exposed to detergents. The carbon chain length of the detergent fatty acid residue (10-18 carbons) appears to be relatively unimportant, but detergents with unsaturated (oleic acid) hydrophobic regions potentiate K+ release and Na+ uptake when compared to the corresponding saturated fatty acid (stearic acid). The erythrocyte stabilizing effect of detergents against hypo-osmotic shock correlates well with the increase of monovalent ion traffic and the mobility of membrane lipids revealed by fluorescence anisotropy measurements.

Release of potassium, lipids, and proteins from nonionic detergent treated chicken red blood cells

The plasma membrane of erythrocytes, as of other cells, is thought to act as the barrier responsible for maintaining intracellular gradients of most ions and small molecular species between the cell and its environment. Controlled application of the nonionic detergent Brij 58 effectively opened the erythrocyte plasma membrane, as judged by electron microscopy and lipid mobilization, but the cytoplasm maintained much of its integrity for about 30 min. Release of K+ correlated well with release of protein into the surrounding medium. The results demonstrate that permeabilization of the erythrocyte plasma membrane does not result in an instantaneous equilibration of small ions, such as K+, between the cell and its environment. A comparison was made between erythrocytes treated with Brij 58 and Triton X-100. The lipid and protein solubilizing actions of Triton X-100 were not as easily separable in time as those of Brij 58. The results of treatment of the erythrocytes with different types of nonionic detergents suggest that the membranolytic and cytoplasmic protein destabilizing actions of nonionic detergents correspond with their hydrophilic-lipophilic balance numbers (HLB values).

Relaxometry, animal biodistribution, and magnetic resonance imaging studies of some new gadolinium (III) macrocyclic phosphinate and phosphonate monoester complexes

The Gd3+ complexes of three new phosphorus containing tetraaza macrocycles (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrakis (methylene ethylphosphonic acid), H4DOTEP; 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrakis (methylene phosphonic acid monoethylester), H4DOTPME; and the corresponding n-butyl ester, H4DOTPMB) were prepared and examined for possible use as MRI contrast agents. Although thermodynamically and kinetically less stable than Gd(DOTA)- in saline and HSA solution, the stability of these new macrocyclic complexes appears to be sufficiently high for in vivo applications. NMRD relaxivity profiles of the three complexes indicate that the number of inner sphere water molecules for these chelates is < or = 1 and that the more hydrophobic chelate, Gd(DOTPMB), binds to human serum albumin (HSA). Biodistribution studies of the radioactive 153Sm or 159Gd chelates in rats, gamma imaging of the 153Sm chelates in rats, and proton MRI studies of the nonradioactive Gd3+ chelates in rabbits all indicate that the DOTPMB complexes accumulate preferentially in the liver, spleen, and small intestines while the more hydrophilic DOTEP and DOTPME complexes appear to display renal clearances similar to other low molecular weight contrast agents.

Effect of the immediate precursors of phenylalanine and tyrosine on growth and protein synthesis in phenylalanine- and tyrosine-deprived HeLa cells

Although Phe is an essential amino acid in mammalian cells, its immediate precursor, beta-phenylpyruvic acid (BPP), when present in Phe-deficient medium at 10(-4) and 10(-3) M is converted at a sufficient rate to Phe to sustain growth at 60 and 100% of non-deficient control HeLa S-3 cells, respectively. In contrast, Tyr-deficient cells were unable to convert the immediate precursor of Tyr, OH-beta-phenylpyruvic acid (OHBPP), nor could BPP rescue Tyr-deficient cells. The results are considered in terms of the organization of intracellular pathways by which precursors are transaminated and made available for protein synthesis.

Relationship between cellular ATP, potassium, sodium and magnesium concentrations in mammalian and avian erythrocytes

Intracellular K+/Na+ ratios of erythrocytes of various mammalian species are known to differ markedly. We have measured ATP, K+, Na+, Mg2+, H2O contents of erythrocytes of twelve mammalian and three avian species. Our results indicate that the intracellular ATP concentration in erythrocytes of different species is in close positive correlation with the K+/Na+ ratios (linear correlation coefficient, r = 0.852). Furthermore, ATP levels in erythrocytes of individual sheep with different potassium concentrations correspond with their K+/Na+ ratios (r = 0.747). Intracellular magnesium concentrations also correlate with ATP concentrations in erythrocytes of different species (r = 0.629) and in different sheep (r = 0.549).

Changes in the concentration of ions during senescence of the human erythrocyte

Flash frozen samples of normal human blood were cryosectioned and cryodried for electron probe x-ray microanalysis of the concentration of ions and elements in individual erythrocytes (RBCs). The data (expressed in mM/kg dry weight) demonstrated a systematic pattern of variation between the concentration of ions and elements in the RBCs. Specifically as K+ and Cl- decreased in concentration, Ca2+ and sulfur increased in concentration. Phosphorous, Na+ and Mg2+ did not demonstrate a significant pattern of change. These findings are related to the dehydration and to the volume decrease that accompanies senescence of the RBC.

Mammalian seryl-tRNA synthetase associates with mRNA in vivo and has homology to elongation factor 1 alpha

Previous work in our laboratories (Slobin, L. I., and Greenberg, J.R. (1988) Eur. J. Biochem. 173, 305-310) showed that messenger ribonucleoprotein (mRNP) particles possess a polypeptide component of approximately 62 kDa that appears to share a common epitope with eucaryotic elongation factor 1 alpha (EF-1 alpha). We report here that the previously unidentified mRNP constituent corresponds to seryl-tRNA synthetase (SerRS). Furthermore, we show that SerRS contains a sequence motif that is shared by both EF-1 alpha and glutaminyl-tRNA synthetase. We also find that the association of SerRS with mRNA depends on the functional state of the latter. Our data suggest that SerRS may participate directly in the initiation phase of protein synthesis.

Ion and water distribution in pig lenses incubated at 0 degree C to disable ion transport pumps

This study was designed to test how extended exposure of lenses to sera with different ionic strengths influences the distribution of ions and water in the lens. Pig lenses were incubated in cold sera (0 degree C), which were adjusted to variable concentrations of NaCl, and their K+, Na+, Cl-, and water contents were measured. Incubation at 0 degree C inhibits active transport processes and thereby allows equilibration of the mobile ions and water. The hypothesis was that lens water content (volume) would follow the ion-induced protein changes predicted by a model derived from previous osmotic studies on proteins. As expected, exposure of the lens to cold caused a gain of sodium and a partial loss of potassium. However, the potassium concentration in the lens remained several fold higher than that in the bathing solution (about 41 vs. 1.8-4.6 mM/kg H2O), indicating that a portion of the potassium within the cold-exposed lens was not free to diffuse. That the water content of the lens showed a negative rather than a positive relationship with the concentration of NaCl within the lens was explained by the idea that an increase in NaCl within the lens (up to at least 250 mM/kg H2O) causes a decrease in the osmotically unresponsive water volume associated with lens proteins.

Proportional equilibration of K, Na ions, and sucrose molecules in pig lenses incubated in the presence of the non-ionic detergent Triton X-100

The release of sodium and potassium and the uptake of sucrose molecules was studied in pig lenses incubated in isosmotic sucrose solution in either the presence or absence of 1% Triton X-100 (a non-ionic detergent). This Triton X-100 treatment has been shown to cause severe disruptions of cell membrane integrity. If sodium and potassium were free in the lens fibers as in a dilute aqueous solution, they would be expected to diffuse three to four times faster than sucrose. However, measurements of sodium and potassium release and sucrose uptake in the Triton X-100 treated lenses show a 1:1 equilibration. When pig lenses were incubated in the same solution without detergent, the sucrose uptake was significantly less than the potassium and sodium release. It is postulated that a slow, detergent mediated collapse of protein-water-ion interactions within the lens is the rate-limiting step of the observed equilibration of monovalent cations and sucrose molecules.

Extent and properties of nonbulk "bound" water in crystalline lens cells

Crystalline lenses provided good material to study and measure the properties of cellular water. Different methods were used to establish the extent and properties of nonbulk water in mammalian lenses. These methods include: NMR titration analysis, a test of the osmotic properties, a test of dye exclusion In lenses with intact cell membranes and in lenses with disrupted cell membranes, and the water-holding capacity of lenses subjected to 40,000 x g for 1 hour with intact cell membranes and in lenses with disrupted cell membranes. The data from these methods, as well as other data from the literature, lead to the conclusion that most, if not all, of the water in lens cells (up to 2.2 g water/g dry mass) has motional and osmotic properties that distinguish it from bulk water. These findings call into question the common and convenient assumption that all but a small proportion of cellular water is like that in dilute solution.