Ben-Zion Ginzburg

Time domain Dielectric Spectroscopy Study of Human Cells. II. Normal and Malignant White Blood Cells

The dielectric properties of human lymphocyte suspensions were studied by time domain dielectric spectroscopy (TDDS). Nine populations of malignant and normal lymphocytes were investigated. Analysis of the dielectric parameters of cell structural parts were performed in the framework of Maxwell-Wagner mixture formula and the double-shell model of cell. The specific capacitance of the cell membranes was estimated by the Hanai-Asami-Koisumi formula. It was shown that the dielectric permittivity, capacitance and conductivity values of cell membranes are higher for normal lymphocytes than for the malignant ones. The difference of the same parameters for normal B- and T-cells is also discussed.

Liquid fuel (oil) from halophilic algae: A renewable source of non-polluting energy

Liquid fuel in the form of a mixture of hydrocarbons has been produced from a renewable form of biomass, the green microalga Dunaliella, which is distributed in oceans and salt lakes throughout the world. The product is a high-quality oil low in sulfur and nitrogen and is obtained by pyrolysis of a suspension of the algal cells. Feasibility studies have determined that the total cost of oil produced from Dunaliella is

Ion metabolism in aHalobacterium : II. Ion concentrations in cells at different levels of metabolism.

21.6 per barrel of crude oil. Allowing for a 20% profit on the investment, the price of a barrel of oil would be

Neutron scattering reveals extremely slow cell water in a Dead Sea organism

26 (Zaidman, School of Applied Chemistry, The Hebrew University of Jerusalem).

Lipid composition of halotolerant algae, Dunaliella parva lerche and Dunaliella tertiolecta

SummaryThe changes in concentration of K+, Na+ and Cl− are given in growing cultures of aHalobacterium species subjected to cold, lack of O2 or starvation. In growing cells, the ion concentration ratios across the cell membrane were 1,000∶1 (inside:outside) for K+ and 1∶2 for Na+. In bacteria with a low rate of endogenous metabolism induced by 24-hr starvation, the ratios were 500∶1 for K+ and 1∶4 for Na+. O2 and a substrate were required for K+ uptake in growing bacteria, but not for the maintenance of K+ and Na+ gradients in starving bacteria. The exchange of K+, Na+ and Li+ across the cell membrane of starving bacteria was found to have a time constant for 50% completion of the process of 20 to 30 sec. The exchange of cell Cl− with NO3− was a twostage process with time constants of approximately 2 min and 2–1/2 hr. The results are explained in terms of the binding of most of the cell K+ which brings about the distribution of Na+ and Cl− according to the Gibbs-Donnan equilibrium; the role of metabolism is to induce changes in the mean ion-activity coefficients.

Light-induced proton uptake in whole cells of Dunaliella parva

Intracellular water dynamics in Haloarcula marismortui, an extremely halophilic organism originally isolated from the Dead Sea, was studied by neutron scattering. The water in centrifuged cell pellets was examined by means of two spectrometers, IN6 and IN16, sensitive to motions with time scales of 10 ps and 1 ns, respectively. From IN6 data, a translational diffusion constant of 1.3 × 10−5 cm2 s−1 was determined at 285 K. This value is close to that found previously for other cells and close to that for bulk water, as well as that of the water in the 3.5 M NaCl solution bathing the cells. A very slow water component was discovered from the IN16 data. At 285 K the water-protons of this component displays a residence time of 411 ps (compared with a few ps in bulk water). At 300 K, the residence time dropped to 243 ps and was associated with a translational diffusion of 9.3 × 10−8 cm2 s−1, or 250 times lower than that of bulk water. This slow water accounts for ≈76% of cell water in H. marismortui. No such water was found in Escherichia coli measured on BSS, a neutron spectrometer with properties similar to those of IN16. It is hypothesized that the slow mobility of a large part of H. marismortui cell water indicates a specific water structure responsible for the large amounts of K+ bound within these extremophile cells.

Interrelationships of light, temperature, sodium chloride and carbon source in growth of halotolerant and halophilic strains of Dunaliella

Abstract The lipids of two halotolerant algae, Dunaliella parva Lerche and Dunaliella tertiolecta , contained predominantly the glycolipids monogalactosyldiacylglycerol (21.4 and 22.2 mol% for D. parva and D. tertiolecta , respectively), digalactosyldiacylglycerol (11.4 and 20.5 mol%), sulfoquinovosyldiacylglycerol (6.5 and 9.5 mol%) and two minor unidentified glycolipids. Phosphatidylcholine (8.8 and 4.4 mol%), phosphatidylglycerol (5.5 and 7.7 mol%) and phosphatidylinositol (1.7 and 2.5 mol%) were present in both algae, but phosphatidylethanolamine (1.9 mol%) and phosphatidic acid (1.7 mol%) were detected in only D. tertiolecta . Diacylglycerol-O-N,N,N-trimethylhomoserine was a large component in both algae (14.2 and 7.5 mol%). The major fatty acids present were linolenic, palmitic, linoleic, oleic and an unidentified acid, probably a polyunsaturated 16-carbon acid. Fatty acid analyses of individual lipids revealed several striking features that were characteristic of the lipids in both algae. In addition, both algae had characteristically high total lipid contents, in the range 20–25% on a cell protein basis.

Extracellular space and cellular sodium content in pellets of Dunaliella parva (Dead Sea, 75)☆

Abstract Light-induced H + uptake (“proton pump’) has been observed with whole cells of the halphilic alga Dunaliella parva . The rate of H + uptake is in the range of 2–6 μequiv H + /min per mg chlorophyll. The extent of the reaction is about 9–10 μequiv H + /mg chlorophyll at an initial pH of 6.2. The extent increases linearly with increase of initial pH. The rate of O 2 evolution decreases parallel to the decrease in rate of H + uptake. Tris and other buffers prevent the decrease in rate of O 2 evolution, decreases parallel to the decrease in rate of H + uptake. Tris and other buffers prevent the decrease in rate of O 2 evolution, and increase the extent of H + uptake. 3(3,4-Dichlorophenyl)-1,1-dimethylurea inhibits H + uptake, but does not affect the decay in the dark. Atebrin and, to a lesser extent, NH 4 Cl increase the rate of decay. Carbonyl cyanide m- chlorophenylhydrazone does not affect the rate of decay at all.

Evidence for active water transport in a corn root preparation

The growth rate of several Dunaliella strains was measured as a function of several environmental parameters. The strains tested fell into two groups, the halotolerant capable of growing at 0·5 m NaCl and above, and the halophilic which cannot grow in media containing less than 2 m NaCl. It proved to be difficult to find optima for the different parameters tested because of their integrated effects within the plant cell; for instance the temperature optimum was higher at high light intensity than at lower intensities. Similarly, higher concentrations of NaCl were tolerated when the light intensity was high and carbon plentiful.

Dielectric properties of the halophilic bacteria Halobacterium halobium and H. marismortui with reference to the conductivities and permittivities of the cytoplasmic membrane and intracellular phases

Abstract Extracellular space (ECS) of pellets of Dunaliella parva (Var. 75) was measured by Dextran Blue. The ECS was found to depend strongly on the centrifugal force. At the highest centrifugal force used it was found to be 3% or less of the pellet water volume. It was shown by micrographs that the low values of ECS were due to the ability of the cells to change their shape. The mean ‘Na+ space’ was found to be 51.3%. It is suggested that most of the Na+ ions are restricted to a compartment in the cell, probably not including the chloroplast.