Proline Oxidase and Water Stress-induced Proline Accumulation in Spinach Leaves

Spinach (Spinacia oleracea L.) leaf discs accumulated free proline when exposed to polyethylene glycol solutions of water potential less than −10 bars. At −20 bars, the accumulation was 11 micromoles per gram original fresh weight in a 24-hour period.     

Potassium and Phosphate Uptake in Corn Roots: Further Evidence for an Electrogenic H/K Exchanger and an OH/Pi Antiporter

Evidence is presented that K⁺ uptake in corn root segments is coupled to an electrogenic H⁺/K⁺ -exchanging plasmalemma ATPase while phosphate uptake is coupled to an OH⁻/Pi antiporter. The plasmalemma ATPase inhibitor, diethylstilbestrol, or the stimulator, fusicoccin, altered K⁺ uptake directly and phosphate uptake indirectly. On the other hand, mersalyl, an OH⁻/Pi antiporter inhibitor, inhibited phosphate uptake instantly but only slightly affected K⁺ uptake. Collapse of the proton gradient across the membrane by (p-trifluoromethoxy) carbonyl cyanide phenylhydrazone resulted in immediate inhibition of K⁺ uptake but only later inhibited phosphate uptake. Changing the pH of the absorption solution had opposite effects on K⁺ and phosphate uptake. In addition, a 4-hour washing of corn root tissue induced a 5-fold increase in the rate of K⁺ uptake with little or no lag, but only a 2- to 3-fold increase in phosphate uptake with a 30- to 45-minute lag. Collectively these differences strongly support the coupling of an electrogenic H⁺/K⁺ -exchanging ATPase to an OH⁻/Pi antiporter in corn root tissue.     

The effect of a moving foveal target on the subjective sensation of motion

In this paper, we report on two experiments concerning the effect of the visual field of fovea on the subjective estimation of angular velocity. Experiment 1 investigates the effect of a slow moving target on the perception of self motion. The result of this experiment can be summarized as follows: a slow moving target seen in the visual field of fovea by a stationary person generates in this person a sensation of self rotation in the same direction as the motion of the target. This phenomenon will be called foveal induced ego motion. Experiment 2 investigates the latency for the detection of a self angular acceleration when the person focusses his fovea on a slowly moving target. From the results of this experiment we conclude that the latency for detection of a small self angular acceleration is shorter if the person sees a small foveal target moving with respect to the person in the direction of self rotation than if that small foveal target is moving (with respect to the person) in the opposite direction. The results of these experiments help us in refining existing models of visual-vestibular interaction, by providing a model which accounts for the phenomenon of oculogyral illusion.This research was conducted while serving as a Visiting Professor at the Man Vehicle Laboratory, Department of Aeronautics and Astronautics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA     

Metabolism of oleoyl-CoA in rat brain synaptosomes

The hydrolysis of acyl-CoA by acyl-CoA hydrolase (EC 3.1.2.2.) in brain synaptosomes was inhibited by calcium. This inhibition was partly due to interaction of Ca²⁺ with the acyl-CoA, which was present in the soluble form, and partly due to complex formation among acyl-CoA, Ca²⁺ and membrane phospholipids. The inhibition of acyl-CoA hydrolase activity, as well as the complex formation. could be reversed if incubation was carried out in the presence of Ca²⁺ chelating agents. Synaptosomes isolated from brain samples after 1 min of postdecapitative treatment showed a decrease in oleoyl-CoA hydrolase activity. The physiological implication of acyl-CoA metabolism in relation to synaptic function is discussed.Abbreviations FFA Free fatty acids - GPC glycerophosphocholines - GPE glycerophosphoethanolamines - GPI glycerophosphoinositols - GPS glycerophosphoserines     

I-A Mutation resulted in a selective loss of an antigen-specific Ir gene function

The immune responses to several antigens were compared in the I-A mutant mouse strain B6.C-H-2^bm12 and the wild-type strain C57BL/6. With a lymph node cell proliferation assay, the response to two of these antigens, beef insulin and (TG)A-L, was demonstrated to be controlled by a gene in the I-A^b region. B6.C-H-2^bm12 mice failed to respond to beef insulin, while their responses to (TG)A-L, DNP-OVA and PPD were comparable with those of the wild-type strain C57BL/6. Taken together with previous studies, these data suggest that the product of a single pleiotropic I-A gene, an la molecule, functions as a histocompatibility, la, and MLR antigen, as well as a necessary component for Ir gene function. Furthermore, the data reported here demonstrate that la molecules have multiple functional “Ir determinants,” one of which has been altered in the B6.C-H-2^bm12 mutant. The B6.C-H-2^bm12 mice, therefore, represent a powerful analytical tool for the understanding of the cellular and molecular basis for Ir gene control of the immune response.     

Ly-m19: The Lyb-2 region of mouse chromosome 4 controls a new surface alloantigen

Spleen cells from an SJL mouse immunized with 70'/3 cells, an established pre-B cell line, were fused with cells of the nonsecretor myeloma line NS.1. One established hybridoma cell line (clone K10.6) continuously secreted antibody that recognized a new antigenic specificity tentatively named Ly-m19. This newly found antigen is detectable on both T and B cells. Cytotoxicity assays reveal that 75 percent of the spleen and lymph-node cells, 35 percent of bone-marrow cells, and 15 percent of thymus cells reacted with antibody of clone K10.6. Strains expressing the specificity Ly-m19.1 are characterized by negative reactions and include the strains AKR, CE/J, RF/J, GR/A, SJL, P/J, BDP/J, and LG/J. All other strains so far tested are Ly-m19.2. This strain distribution pattern distinguishes Ly-m19 from any known murine lymphocyte alloantigen, but it parallels the Lyb-2 ^c haplotype. Linkage test of a set of AKXL recombinant inbred strains revealed close linkage of Ly-m19 and Lyb-2 loci on mouse chromosome 4.Abbreviations used in this paper LPS lipopolysaccharide - B6 C57BL/6 - Con-A concanavalin A - MLC mixed-lymphocyte culture The prefix m (monoclonal) is used following a suggestion by Klein and co-workers (1979).     

Microwave treatment of intracerebral l1210 leukemia: Schedule-dependent partial reversal of the effects of methotrexate

One-GHz microwave (MW) irradiation at a power density of 5 mW/cm² was combined with methotrexate (MTX) in an attempt to treat more effectively central nervous system (CNS) L1210 leukemia in DBA/2J mice. When mice with CNS leukemia were treated with the combination of MW and MTX, there was no improvement in survival compared with a group of animals treated with MTX alone; however, the group that received MTX before the MW exposure had a significantly reduced survival time compared with the group treated with MTX alone or with the group to which MTX was administered after MW.     

In vitro microwave effects on human neutrophil precursor cells (CFU-C)

Human marrow cells were irradiated with 2450-MHz CW microwaves in a fluid-filled waveguide irradiation system. Cell exposure was conducted by placing a marrow cell suspension in 20-μl glass microcapillary tubes that were positioned in the exposure chamber, and irradiated at power densities from 31 to 1,000 mW/cm² (with corresponding specific absorption rates of 62 to 2,000 mW/g) for 15 minutes. The temperature of the sample was maintained at a fixed point. Sham-irradiated (SI) and microwave-irradiated (MWI) cells were cultured in a methylcellulose culture system for neutrophil colony proliferation. There was no reduction in neutrophil colony number on days 6–7 or 12–14 in cells exposed at 31 or 62 mW/cm², but as the power density was increased to 1,000 mW/cm², there was a reduction in colony number of MWI cells compared with SI cells. The microwave interaction with the human neutrophil colony-forming cells was apparently not related to temperature rise, or to the state of cell cycle, and was irreversible.     

Size characteristics of human leucocyte interferon under reducing and non-reducing conditions.

Sodium dodecyl sulphate/polyacrylamide-gel electrophoresis was used to characterize human leucocyte interferon (HuIFN-alpha) under reducing and non-reducing conditions. Under non-reducing conditions HuIFN-alpha possesses two size forms, but under reducing conditions (r-HuIFN-alpha) only one is observed. The apparent molecular weight of this one form varies with the concentration of 2-mercaptoethanol used. When r-HuIFN-alpha is permitted to reoxidize the bimodal configuration of HuIFN-alpha is restored. The size heterogeneity of native HuIFN-alpha can be eliminated by mild treatment with NaIO4 [HuIFN-alpha/IO4; Stewart II, Lin, Wiranowska-Stewart & Cantell (1977) Proc. Natl. Acad. Sci. U.S.A. 74, 4200-4204]. The size of the HuIFN-alpha/IO4 increases after treatment with 2-mercaptoethanol (r-HuIFN-alpha/IO4) and the apparent molecular weight of this component also varies with the concentration of 2-mercaptoethanol used. In the case of r-HuIFN-alpha the single peak observed apparently originates from both the higher- and lower-molecular-weight components.     

Autoradiographic studies with 3H 1,25 (OH)2 vitamin D3 and 3H 25 (OH) vitamin D3 in rat parathyroid glands

Summary After injection of radiolabeled 1,25 (OH)₂ vitamin D₃, nuclear concentration of radioactivity is observed in parenchymal cells of the parathyroid gland in pregnant, adult male, and 10-day male neonatal rats. In competition studies with unlabeled 1,25 (OH)₂ vitamin D₃, but not with 25 (OH) vitamin D₃, nuclear uptake is prevented. Experiments with ³H 25 (OH) vitamin D₃, in contrast to ³H 1,25 (OH)₂ vitamin D₃, do not show nuclear concentration in cells of the parathyroid. The results of the autoradiographic studies suggest the presence of receptors for a direct effect of 1,25 (OH)₂ vitamin D₃ on the parathyroid gland for modulation of parathyroid hormone secretion.