Induction of Rishitin and Lubimin Synthesis in Potato Tuber Slices by Non-Specific Elicitors — Role of Gene Derepression

1979 ◽  
Vol 42 (6) ◽  
pp. 512-518 ◽  
Author(s):  
A. S. CHEEMA ◽  
N. F. HAARD
Keyword(s):  
Potato Tuber ◽  
Mrna Translation ◽  
Metabolic Inhibitors ◽  
Protein Synthesis Inhibitors ◽  
High Concentration ◽  
Low Concentrations ◽  
Translation Block ◽  
Heavy Metal Salts ◽  
Stress Metabolites

The stress metabolites rishitin and lubimin accumulate at relatively low concentrations (5–20 ppm) in potato tuber slices subjected to various cell-disruptive treatments including heavy metal salts, sulfhydryl reagents, metabolic inhibitors, detergents, ultraviolet light and lysosomal enzymes. Cold-stored (4 C) tubers are more disposed to terpene accumulation than freshly harvested, 25-C stored and conditioned potatoes. Various inhibitors of DNA transcription and mRNA translation block terpene induction by non-specific elicitors when applied at sufficiently high concentration. However. various protein synthesis inhibitors were shown to be potent elicitors of terpene accumulation when applied at lower concentration. Actinomycin D (25 μg/ml) treatment of discs for 30 min elicits higher levels of rishitin than results from Phytophthora infestans interaction with potato (> 100 ppm). A mechanism for terpene induction based on derepression of “stress metabolite DNA” is proposed to explain the experimental data.

Abstract 203: Protein Synthesis Inhibitors 4E-BPs Regulate Cardiac Function

2012 ◽  
Vol 111 (suppl_1) ◽  
Author(s):  
Denghong Zhang ◽  
Riccardo Contu ◽  
Michael Latronico ◽  
Kirk Peterson ◽  
Ju Chen ◽  
...  
Keyword(s):  
Heart Failure ◽  
Protein Synthesis ◽  
Cardiac Function ◽  
Pressure Overload ◽  
Mrna Translation ◽  
Protein Synthesis Inhibitors ◽  
Negative Effects ◽  
Hypertrophic Response ◽  
Improvement In Survival

Rationale: mTOR regulates cardiac functionality and hypertrophy. We have shown that cardiac-specific deletion of mTOR induces fatal dilated cardiomyopathy. This model of heart failure is characterized biochemically by accumulation of the mTOR substrate 4E-BP1, which inhibits protein synthesis through the regulation of translation initiation. Deletion of the 4E-BP1 gene, Eif4ebp1, in mTOR-KO mice significantly, albeit partially, improved cardiac function and survival. Objective: To investigate the role of the 4E-BP family in the heart by determining whether absence of its members improves cardiac function in different models of heart failure. Methods and Results: In the absence of Eif4ebp1, cardiac expression of the 4E-BP2 homolog increases strikingly. Deletion of Eif4ebp2 along with Eif4ebp1 (4E-BP1/4E-BP2-dKO mice) abrogated the negative effects of the loss of mTOR on cardiac function, and led to a further significant improvement in survival rate. Moreover, when 4E-BP1/4E-BP2-dKO mice where subjected to pressure-overload stress, cardiac function and survival were significantly improved compared with similarly treated control mice. The hypertrophic response to pressure overload in these mice was not affected by the absence of 4E-BPs. Conclusions: Our data indicate that 4E-BPs are responsible for an important part of mTOR effects on cardiac function, further strengthening the concept that the regulation of mRNA translation profoundly affects cardiac inotropism under stress.

Influence of Location of a Fluorescent Zinc Probe in Brain Slices on Its Response to Synaptic Activation

2006 ◽  
Vol 95 (3) ◽  
pp. 1949-1956 ◽  
Author(s):  
Alan R. Kay ◽  
Katalin Tóth
Keyword(s):  
Fluorescent Probes ◽  
Synaptic Vesicles ◽  
Hippocampal Slices ◽  
Brain Slices ◽  
Live Cells ◽  
High Concentration ◽  
Low Concentrations ◽  
Powerful Approach ◽  
Precise Role

The precise role of the high concentration of ionic zinc found in the synaptic vesicles of certain glutamatergic terminals is unknown. Fluorescent probes with their ability to detect ions at low concentrations provide a powerful approach to monitoring cellular Zn2+ levels. In the last few years, a number of fluorescent probes (indicators) have been synthesized that can be used to visualize Zn2+ in live cells. The interpretation of data gathered using such probes depends crucially on the location of the probe. Using acutely prepared hippocampal slices, we provide evidence that the Zn2+ probes, ZnAF-2 and ZP4, are membrane permeant and are able to pass into synaptic vesicles. In addition, we show that changes in fluorescence of the Zn2+ probes can be used to monitor presynaptic activity; however, these changes are inconsistent with Zn2+ release.

Functional Role of Ca2+ Currents in Graded and Spike-Mediated Synaptic Transmission Between Leech Heart Interneurons

1997 ◽  
Vol 77 (4) ◽  
pp. 1779-1794 ◽  
Author(s):  
Jin Lu ◽  
John F. Dalton ◽  
Darrell R. Stokes ◽  
Ronald L. Calabrese
Keyword(s):  
Synaptic Transmission ◽  
Voltage Clamp ◽  
Functional Role ◽  
Inactivation Kinetics ◽  
High Concentration ◽  
Outward Currents ◽  
Low Concentrations ◽  
Low Threshold ◽  
Kinetics Of

Lu, Jin, John F. Dalton, IV, Darrell R. Stokes, and Ronald L. Calabrese. Functional role of Ca2+ currents in graded and spike-mediated synaptic trnasmission between leech heart interneurons. J. Neurophysiol. 77: 1779–1794, 1997. We used intracellular recording and single electrode voltage-clamp techniques to explore Ca2+ currents and their relation to graded and spike-mediated synaptic transmissions in leech heart interneurons. Low-threshold Ca2+ currents (activation begins below −50 mV) consist of a rapidly inactivating component ( I CaF) and a slowly inactivating component ( I CaS). The apparent inactivation kinetics of I CaF appears to be influenced by Ca2+; both the substitution of Ca2+ (5 mM) with Ba2+ (5 mM) in the saline and the intracellular injection of the rapid Ca2+ chelator, bis-( o-aminophenoxy)- N,N,N′,N′-tetraacetic acid (BAPTA), from the recording microelectrode, significantly increase its apparent inactivation time constant. The use of saline with a high concentration of Ba2+ (37.5 mM) permitted exploration of divalent ion currents over a broader activation range, by acting as an effective charge carrier and significantly blocking outward currents. Ramp and pulse voltage-clamp protocols both reveal a rapidly activating and inactivating Ba2+ current ( I BaF) and a less rapidly activating and slowly inactivating Ba2+ current with a broad activation range ( I BaS). Low concentrations of Cd2+ (100–150 μM) selectively block I BaS, without significantly diminishing I BaF. The current that remains in Cd2+ lacks the characteristic delayed activation peak of I BaS and inactivates with two distinct time constants. I BaF appears to correspond to a combination of I CaF and I CaS, i.e., to low-threshold Ca2+ currents, that can be described as T-like. I BaS appears to correspond to a Ca2+ current with a broad activation range, which can be described as L-like. Cd2+ (100 μM) selectively blocks spike-mediated synaptic transmission between heart interneurons without significantly interfering with low-threshold Ca2+ currents and plateau formation in or graded synaptic transmission between heart interneurons. Blockade of spike-mediated synaptic transmission between reciprocally inhibitory heart interneurons with Cd2+ (150 μM), in otherwise normal saline, prevents the expression of normal oscillations (during which activity in the two neurons consists of alternating bursts), so that the neurons fire tonically. We conclude that graded and spike-mediated synaptic transmission may be relatively independent processes in heart interneurons that are controlled predominantly by different Ca2+ currents. Moreover, spike-mediated synaptic inhibition appears to be required for normal oscillation in these neurons.

scholarly journals Ca2+ transport by the luminal membrane of the distal nephron: action and interaction of protein kinases A and C

1997 ◽  
Vol 328 (2) ◽  
pp. 371-375 ◽  
Author(s):  
Georges HILAL ◽  
David CLAVEAU ◽  
Marie LECLERC ◽  
Michèle G. BRUNETTE
Keyword(s):  
Phospholipase C ◽  
Protein Kinases ◽  
Distal Tubule ◽  
High Concentration ◽  
Protein Kinase C Inhibitors ◽  
Luminal Membrane ◽  
Low Concentrations ◽  
Distal Tubules ◽  
High Concentrations

We previously reported that parathyroid hormone and calcitonin increase Ca2+ uptake by purified distal luminal membranes. This effect is mimicked by high concentrations of cAMP. However, both hormones stimulate adenylate cyclase and phospholipase C. The purpose of the present study was to investigate the role of the phospholipase C pathway in the hormone action, and the interrelationship between the two messengers. Distal tubules from rabbit kidneys were incubated with dibutyryl cAMP (dbcAMP) or PMA, or both, and Ca2+ uptake by purified luminal membranes was measured by the rapid filtration technique. Incubation of the distal tubules with 1 mM dbcAMP significantly increased Ca2+ transport by the luminal membranes. A dose-response curve showed a half-maximal stimulation with 0.82 mM dbcAMP. In contrast, treatment of the tubules with 10 nM, 100 nM or 1 μM PMA did not influence Ca2+ uptake by these membranes. However, the addition of 100 nM PMA to low concentrations of dbcAMP strongly increased this uptake. The presence of cAMP or protein kinase C inhibitors prevented the effects of either a high concentration of dbcAMP alone or a low concentration of dbcAMP combined with 100 nM PMA. Our laboratory has already reported that Ca2+ uptake by the distal luminal membranes displays two-component kinetics. dbcAMP increased the Vmax of the low-affinity component, whereas a combination of the two messengers stimulated the Vmax of both the low- and high-affinity components. From these results, we conclude that: (1) in the distal tubule cells, activation of both protein kinases A and C is necessary for the stimulation of Ca2+ transport by the luminal membrane; (2) the combined effect of protein kinases A and C involves both components of the Ca2+-transport kinetics.

scholarly journals Possible role of lipoprotein lipase in the regulation of endogenous triacylglycerols in the rat heart

1981 ◽  
Vol 198 (1) ◽  
pp. 159-166 ◽  
Author(s):  
W K Palmer ◽  
R A Caruso ◽  
L B Oscai
Keyword(s):  
Lipoprotein Lipase ◽  
Lipase Activity ◽  
Rat Heart ◽  
Lipoprotein Lipase Activity ◽  
High Concentration ◽  
Perfused Heart ◽  
Low Concentrations ◽  
Biphasic Effect ◽  
Triacylglycerol Content

1. Adrenaline has a biphasic effect on intracellular lipoprotein lipase activity and on endogenous triacylglycerol content in heparin-perfused heart. 2. A high concentration of adrenaline (1 microM in the perfusion buffer) activated endogenous lipoprotein lipase activity and, at the same time, decreased intracellular triacylglycerol stores. 3. In contrast, a low concentration (0.005 microM-adrenaline) inhibited intracellular lipoprotein lipase activity. Under these conditions, cardiac triacylglycerol content was elevated above control values. 4. Perfusing the heart with high and low concentrations of 3-isobutyl-1-methylxanthine elicited a biphasic effect on endogenous lipoprotein lipase activity and triacylglycerol content similar to that seen with adrenaline treatment. 5. The effect of adrenaline on intracellular lipoprotein lipase activity appears to be mediated by cyclic AMP through protein kinase. 6. A possible role for intracellular lipoprotein lipase in the regulation of endogenous triacylglycerol in rat heart is proposed.

scholarly journals ROLE OF BIOLOGICAL PROCESSES DURING MANGANESE REMOVAL FROM UNDERGROUND WATER

2016 ◽  
Vol 1 ◽  
pp. 61-67
Author(s):  
Oleksandr Kravchenko
Keyword(s):  
Significant Role ◽  
Underground Water ◽  
Biological Processes ◽  
High Concentration ◽  
Manganese Removal ◽  
Low Concentrations ◽  
Physico Chemical ◽  
High Level ◽  
Manganese Compounds

This article briefly presents the results of the effect of oxidants during filtration of groundwater with high level of manganese compounds. Significant role of biological processes along with physico-chemical at demanganation of groundwater has been noticed. It has been studied that biological processes are dominated in low concentrations of oxidants. At high concentration of disinfectant the role of physico-chemical processes begin to dominate. Thus, there is a significant role of microorganisms in physico-chemical process of manganese removal. Obtained results showed that the oxygen is more efficient oxidizer than sodium hypochlorite for compounds of manganese presented in groundwater.

Testosterone Potentiation of Ionophore and ADP Induced Platelet Aggregation : Relationship to Arachidonic Acid Metabolism

1981 ◽  
Vol 46 (02) ◽  
pp. 538-542 ◽  
Author(s):  
R Pilo ◽  
D Aharony ◽  
A Raz
Keyword(s):  
Arachidonic Acid ◽  
Platelet Aggregation ◽  
Unsaturated Fatty Acids ◽  
Human Platelet ◽  
Platelet Rich Plasma ◽  
Arachidonic Acid Metabolism ◽  
Ionophore A23187 ◽  
Low Concentrations ◽  
Induced Aggregation

SummaryThe role of arachidonic acid oxygenated products in human platelet aggregation induced by the ionophore A23187 was investigated. The ionophore produced an increased release of both saturated and unsaturated fatty acids and a concomitant increased formation of TxA2 and other arachidonate products. TxA2 (and possibly other cyclo oxygenase products) appears to have a significant role in ionophore-induced aggregation only when low concentrations (<1 μM) of the ionophore are employed.Testosterone added to rat or human platelet-rich plasma (PRP) was shown previously to potentiate platelet aggregation induced by ADP, adrenaline, collagen and arachidonic acid (1, 2). We show that testosterone also potentiates ionophore induced aggregation in washed platelets and in PRP. This potentiation was dose and time dependent and resulted from increased lipolysis and concomitant generation of TxA2 and other prostaglandin products. The testosterone potentiating effect was abolished by preincubation of the platelets with indomethacin.

Effect of High Salt Concentration on Ion Clustering and Transport in Polymer Solid Electrolytes: a Molecular Dynamics Study of PEO-LiTFSI

2018 ◽  
Author(s):  
Nicola Molinari ◽  
Jonathan P. Mailoa ◽  
Boris Kozinsky
Keyword(s):  
Polymer Electrolyte ◽  
Salt Concentration ◽  
Rational Design ◽  
Material System ◽  
Ion Dynamics ◽  
High Concentration ◽  
Anion Clusters ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene

<div> <div> <div> <p>The model and analysis methods developed in this work are generally applicable to any polymer electrolyte/cation-anion combination, but we focus on the currently most prominent polymer electrolyte material system: poly(ethylene) oxide/Li- bis(trifluoromethane) sulfonamide (PEO + LiTFSI). The obtained results are surprising and challenge the conventional understanding of ionic transport in polymer electrolytes: the investigation of a technologically relevant salt concentration range (1 - 4 M) revealed the central role of the anion in coordinating and hindering Li ion movement. Our results provide insights into correlated ion dynamics, at the same time enabling rational design of better PEO-based electrolytes. In particular, we report the following novel observations. 1. Strong binding of the Li cation with the polymer competes with significant correlation of the cation with the salt anion. 2. The appearance of cation-anion clusters, especially at high concentration. 3. The asymmetry in the composition (and therefore charge) of such clusters; specifically, we find the tendency for clusters to have a higher number of anions than cations.</p> </div> </div> </div>

Effect of High Salt Concentration on Ion Clustering and Transport in Polymer Solid Electrolytes: a Molecular Dynamics Study of PEO-LiTFSI

2018 ◽  
Author(s):  
Nicola Molinari ◽  
Jonathan P. Mailoa ◽  
Boris Kozinsky
Keyword(s):  
Polymer Electrolyte ◽  
Salt Concentration ◽  
Rational Design ◽  
Material System ◽  
Ion Dynamics ◽  
High Concentration ◽  
Anion Clusters ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene

<div> <div> <div> <p>The model and analysis methods developed in this work are generally applicable to any polymer electrolyte/cation-anion combination, but we focus on the currently most prominent polymer electrolyte material system: poly(ethylene) oxide/Li- bis(trifluoromethane) sulfonamide (PEO + LiTFSI). The obtained results are surprising and challenge the conventional understanding of ionic transport in polymer electrolytes: the investigation of a technologically relevant salt concentration range (1 - 4 M) revealed the central role of the anion in coordinating and hindering Li ion movement. Our results provide insights into correlated ion dynamics, at the same time enabling rational design of better PEO-based electrolytes. In particular, we report the following novel observations. 1. Strong binding of the Li cation with the polymer competes with significant correlation of the cation with the salt anion. 2. The appearance of cation-anion clusters, especially at high concentration. 3. The asymmetry in the composition (and therefore charge) of such clusters; specifically, we find the tendency for clusters to have a higher number of anions than cations.</p> </div> </div> </div>

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