Characterization of interleukin 2 stimulated 65-kilodalton phosphoprotein in human T cells

We have characterized the cellular proteins which are rapidly phosphorylated by interleukin 2 (IL 2) in a human IL 2 dependent cell line. When treated with IL 2, the phosphorylation of five proteins, 65, 50, 37, 24, and 21 kDa, was found in IL 2 dependent cell lines by two-dimensional gel electrophoretic analysis. After cell conversion from an IL 2 dependent state to an IL 2 independent state, one of the five phosphoproteins, the 65-kDa protein, became constitutively phosphorylated even without addition of IL 2. Also, in other IL 2 independent cell lines, such as KUT-2 and HUT-102, constitutive phosphorylation of the 65-kDa protein occurred without IL 2-stimulation. So our researchers were focused on biochemical characterization of the 65-kDa protein. It was found that the 65-kDa protein was one of the major cellular proteins by comparing the results of two-dimensional gel electrophoretic analysis of [32P]Pi-labeled and [3H]leucine-labeled cellular proteins and peptide mapping analysis. Subcellular fractionation studies indicated that the 65-kDa protein is a cytosol protein. The 65-kDa protein was purified from cytosol of a human T cell line, and its amino acid composition and amino acid sequences of its three oligopeptides were determined. It was found that the 65-kDa protein is identical with 1-plastin.     

Recovery of uranium by immobilized microorganisms

Summary Some attempts were made to recover uranium from sea and fresh water using immobilized Streptomyces viridochromogenes and Chlorella regularis cells. The cells immobilized in polyacrylamide gel have the most favorable features for uranium recovery; high adsorption ability, good mechanical properties, and applicability in a column system. The adsorption of uranium by the immobilized cells is not affected by the pH values between 4 and 9. These results show that uranium adsorption becomes independent of pH after immobilization. The amounts of uranium adsorbed by the immobilized cells increased linearly with temperature, suggesting that the adsorption of uranium by the immobilized cells is an endothermic reaction. The immobilized cells can recover uranium almost quantitatively from both fresh and sea water containing uranium, and almost all uranium adsorbed is desorbed with a solution of Na₂CO₃. Thus the immobilized cells of Streptomyces and Chlorella can be used repeatedly in adsorption-desorption process.Studies on the Accumulation of Heavy Metal Elements in Biological Systems. XXI     

Role of prostaglandin endoperoxides in the serum thiobarbituric acid reaction

In the presence of heme and reduced glutathione, prostaglandin (PG) endoperoxides underwent rapid conversion to malondialdehyde and 12l-hydroxy-5,8,10-heptadecatrienoic acid. In addition, PG endoperoxides as well as lipid peroxides produced malondialdehyde to yield a red pigment during the thiobarbituric acid reaction with different efficiencies. The relative rates of the reaction were: 1,1,3,3-tetraethoxypropane, 100; PGG₂, 55; PGH₂, 32; and 15-hydroperoxyarachidonic acid, 6. The thiobarbituric acid reactive materials in rabbit serum decreased by 25–60%, after intravenous administration of aspirin (a cyclo-oxygenase inhibitor) and with a concomitant decline of serum PG levels. These results, taken together, suggested that serum thiobarbituric acid values, considered to be an indicator of lipid peroxide levels, were to a significant extent due to PG endoperoxides and their derivatives.     

Electrotonic Coupling between Adjacent Internodal Cells of Chara braunii: Transmission of Action Potentials beyond the Node

Many nodal cells are interposed between two internodal cellsof Chara braunii. When an action potential conducted in an internodereached the node, no electrical activation in the nodal cellscould be found, although an area of the membrane bordering thenodal cells in this internode was partially activated (end-membraneaction potential). When the action potential approached thenode along the stimulated internode, an electrotonic potentialchange (depolarization) was produced in the other internode.This depolarization was greatly depressed by the end-membraneaction potential of the stimulated internode, so that hardlyany transmission took place. The ratio of the potential changein the surface membrane of the adjoining ("postsynaptic") internode(cell b) to that of the stimulated one (cell a), the couplingratio, e_b/e_a, can be estimated from a simple equivalent circuitof the nodal region composed of two surface-membrane resistances(R_a, R_b) and intercellular resistance (R_n). If R_n remains thesame, a higher ratio should be produced with a larger R_b, butthe ratio does not depend on any change in R_a, which could beproved experimentally. Transmission of the action potentialbeyond the node was frequent when the coupling ratio was increasedand when the threshold that elicits the action potential waslowered by immersing the node in a K or Na salt solution. ¹ Present address: Department of Physiology, Tohoku UniversitySchool of Dentistry, Sendai 980, Japan. (Received December 1, 1980; Accepted January 23, 1981)     

Phase progress under low temperature treatment of the potassium uptake rhythm in a duckweed, Lemna gibba G3

Potassium uptake rhythm in the long-day duckweed Lemna gibbaG3 grown at 26?C disappeared at temperatures below 12?C. However,when the plants were returned to 26?C, the rhythm immediatelyrestarted from circadian time 12 with its normal wave form.Temperature steps from 20 to 30?C or from 30 to 20?C did notmodify the phase of the rhythm, although a step from 15 to 30?Cor from 30 to 15?C evoked a distortion in the wave form withoutintroducing any reproducible phase shift. Various periods of 9 or 4?C given during the subjective dayphase reduced the pace of rhythm progress by 40 or 60%, whilethose given during the subjective night phase did not. Theseresults suggest that the subjective day and night phases arethe energy charge and discharge phases for the underlying oscillator,respectively. Energy fluxes for the oscillators are brieflydiscussed. ¹Present address: National Institute for Basic Biology, Okazaki444, Japan. ²Present address: Aichi Gakuin University, Chikusa, Nagoya 464,Japan. (Received August 25, 1979; )     

Energy supply for potassium uptake rhythm in a duckweed, Lemna gibba G3

The energy relationships of the potassium uptake rhythm in aflow-medium culture of a duckweed, Lemna gibba G3, were investigated. Respiratory inhibitors or uncouplers (NaCN, 2,4-dinitrophenoland carbonyl-cyanide m-chlorophenylhydrazon) reduced the mesoror the average rate of potassium uptake, without remarkablydecreasing the amplitude of the rhythm. NaN₃, however, preferablysurpressed the amplitude at a concentration as low as 10^–6M. Both dichloro-phenyldimethylurea and the removal of CO₂ graduallydecreased the average rate of the uptake, although the rhythmicityitself was not eliminated completely in the absence of CO₂.In N₂, the average rate of uptake was reduced to zero, but rhythmwith a small amplitude survived. These observations suggested that respired photosynthates provideenergy for sustaining the average of potassium uptake and thatsome light dependent processes control the amplitude of therhythm. Exogenous sugar could make the potassium uptake rhythmappear for a relatively short time in the dark. ¹This study was carried out in the National Institute for BasicBiology and the Biological Institute, Faculty of Science, NagoyaUniversity (Received October 24, 1979; )     

Limited autolysis of Ca2+-activated neutral protease (CANP) changes its sensitivity to Ca2+ ions

Ca2+-activated neutral protease (CANP) usually requires mM Ca2+ for activation. The sensitivity of CANP to Ca2+ is greatly enhanced by passing it through a casein-Sepharose column in the presence of Ca2+ ions. This conversion is ascribed to autolysis of CANP. The converted enzyme required 40 microM Ca2+ for 50% activation. Various properties of the converted enzyme were very similar to those of CANP-I, recently found in canine heart muscle. Names of "m-CANP" and "mu-CANP" are proposed for CANPs which require mM and microM order Ca2+ for inactivation, respectively.     

Comparison of lactate and malate dehydrogenases: Fluorescence and thermodynamic properties

Equilibrium, thermochemical, and time-resolved fluorescence measurements have been carried out in order to compare pig heart lactate dehydrogenase (LDH) and cytoplasmic malate dehydrogenase (MDH). The differences in the thermodynamic parameters for binding of NADH and NAD+ show the same pattern for both enzymes. The stronger binding of NADH is entropy-based, which can be understood as reflecting electrostatic interactions. The tryptophan fluorescence of MDH and LDH differ for the free enzymes and in quenching by NADH. The differences can be accounted for in terms of a single long-lived tryptophan residue present in LDH and not in MDH.     

Ionic composition and pH of the vacuolar sap in marine dinoflagellate Noctiluca

Ionic composition of the vacuolar sap of Noctiluca miliariswas as follows: [Na⁺] = 487.3 mM, [K⁺]=24.1 mM, [Ca²⁺]=6.6 mM,[Mg²⁺]=2.8 mM, [Cl^–]=500mM, [NH₄⁺]=15–25 mM, and[SO₄^2–]=undetectable. To measure the vacuolar pH of singleliving cells, a pH-sensitive glass microelectrode was used.The vacuolar pH value was 3.50 ±0.18. When the cellswere transferred from normal sea water into osmotically adjusted50% sea water for one day, the vacuolar ion concentrations remainedalmost constant. Upon immersing the cells in osmotically unadjustedsea water of various concentrations for one day, the observedincrements or decrements of the vacuolar ion concentrationscould be accounted for largely by the migration of water outof or into the cells. The intrinsic ionic composition of thevacuole seems to be constant against changes in ion concentrationsof the bathing medium. (Received October 20, 1975; )     

Adenylate regulation of photosynthetic electron transport and the coupling sites of phosphorylation in spinach chloroplasts

The regulation by adenylates of activities of various partial electron transport systems in spinach chloroplasts was studied using systems from H₂O to 2,5-dimethyl-p-benzoquinone, H₂O to 2,6-dichlorophenolindophenol, reduced 2,6-dichlorophenolindophenol to methyl viologen, and H₂O to methyl viologen or ferricyanide. Adenylates regulated all of them. The ratio of the amount of esterified Pi (P) to that of electrons transported (e) in coupling with phosphorylation manifested that there are two phosphorylation sites: one between H₂O and 2,5-dimethyl-p-benzoquinone or 2,6-dichlorophenolindophenol and another between reduced 2,6-dichlorophenolindophenol and methyl viologen, under the proposed stoichiometries,i.e., P/H⁺=0.5 and H⁺/e=1, where H⁺ is the amount of protons pumped by electron transport (= those translocated during phosphorylation), when the basal electron transport (the part not regulated by adenylates) was excluded. The effects of pH, phlorizin, and methylamine on the adenylate regulation of electron transport, and the stimulation profile of electron transport coupled with quasiarsenylation suggested no distinction between the two phosphorylation sites.