The Role of Sodium in the Conversion of Pyruvate to Phosphoenolpyruvate in Mesophyll Chloroplasts of C4 Plants

1996 ◽  
Vol 23 (2) ◽  
pp. 171 ◽  
Author(s):  
PF Brownell ◽  
LM Bielig
Keyword(s):  
Oxygen Evolution ◽  
Malic Enzyme ◽  
Small Samples ◽  
Panicum Miliaceum ◽  
Tight Coupling ◽  
Irreversible Damage ◽  
C4 Species ◽  
The Hill

PEP formation from pyruvate was determined in mesophyll chloroplasts mechanically isolated from sodium-deficient and sodium-replete plants of the NADP malic enzyme-type C4 species, Kochia trichophylla. An extremely sensitive method for estimating PEP was developed which permitted determination of picomole quantities of PEP in small samples taken sequentially from the mesophyll chloroplast suspension concurrently with observations on oxygen evolution. It was shown that PEP formation requires light and depends upon the intactness of the chloroplasts. The rate of formation of PEP from pyruvate increased in the presence of the Hill reagent, oxaloacetate, thus indicating its dependence on non-cyclic photophosphorylation for the supply of ATP required in the conversion of pyruvate to PEP. The optimum inorganic phosphate concentration for PEP formation was approximately 16 mM. The rates of oxygen evolution and PEP formation were equivalent at concentrations of pyruvate up to 20 mM, suggesting tight coupling between electron transport and phosphorylation. In both Kochia trichophylla and the NAD malic enzyme-type, Panicum miliaceum, the rates of PEP formation were greater in the mesophyll chloroplasts from sodium-replete than from sodium-deficient plants. Chloroplasts resuspended in 'sodium-free'media containing less than 30 μM (0.7 ppm) sodium showed reduced rates of PEP formation compared with chloroplasts resuspended in media to which 1.0 mM (23 ppm) sodium had been added. Both media contained 10 mM 'sodium-free' KCI. These results indicate that sodium ions may be required to maintain the functional integrity of the mesophyll chloroplasts and that irreversible damage is sustained when sodium is absent during their isolation.

A Primer on the Federal Budget Process

MRS Bulletin ◽  
1990 ◽  
Vol 15 (11) ◽  
pp. 35-35
Author(s):  
Robert L. Post
Keyword(s):  
Federal Budget ◽  
Fiscal Year ◽  
Budget Process ◽  
White House ◽  
Select Group ◽  
The Subject ◽  
Federal Budget Process ◽  
The Hill

The federal budget process is often regarded as an arcane affair, the province of a select group of Washington insiders. This includes the mysteries behind the determination of budgets for R&D on materials. The purpose of this discussion is to demysrify the subject a little. It will focus largely on the role of Congress.A common misconception is that the White House sets the budget for the federal government. What the White House does do is send detailed recommendations to Congress each year in January on what it believes the budget should be. This covers spending, tax policy, and economie predictions (the latter reflected in the anticipated tax revenues). In January 1990, for example, the administration submitted budget recommendations for fiscal year 1991, which began on October 1 and runs until September 30, 1991. These recommendations (with subsequent negociations with the Hill) can be quite influential, but serve primarily as a point of reference, which Congress can gladly accept, or completely ignore, as circumstances and preferences dictate.

Light-Dependent Metabolism of Carbon Compounds by Mesophyll Chloroplasts from Plants with the C4 Pathway of Photosynthesis

1974 ◽  
Vol 1 (1) ◽  
pp. 51 ◽  
Author(s):  
T Kagawa ◽  
MD Hatch
Keyword(s):  
Outer Membrane ◽  
Oxygen Evolution ◽  
Carbon Metabolism ◽  
Initial Rate ◽  
Dihydroxyacetone Phosphate ◽  
C4 Species ◽  
Carbon Compounds ◽  
C4 Pathway

This paper describes the capacities of intact mesophyll chloroplasts prepared from Atviplex spongiosa and maize for the light-dependent metabolism of carbon compounds. Illuminated chloroplasts converted pyruvate to phosphoenolpyruvate but the initial rate was maintained only when either 3-phosphoglycerate or methylviologen was added. Light-dependent oxygen evolution was observed when 3-phosphoglycerate or oxaloacetate was added to chloroplasts, and the concomitant production of dihydroxyacetone phosphate or malate was observed. The addition of ADP or NADP or both did not produce increases in these activities. Addition of the photophosphorylation uncoupler methylamine stimulated the rate of oxaloacetate reduction and inhibited the conversion of 3-phosphoglycerate to dihydroxyacetone phosphate. These chloroplasts were not capable of oxygen evolution upon the addition of bicarbonate and did not fix CO2. The data also provided information about minimum rates of influx or efflux of metabolites through the chloroplast outer membrane. These studies confirmed that mesophyll chloroplasts of C4 species are unique in terms of their cap- acities for carbon metabolism. These activities are discussed in relation to the role of mesophyll chloroplasts in C4-pathway photosynthesis.

Aspartate Decarboxylation in Bundle Sheath Cells of Zea mays and Its Possible Contribution to C3 Photosynthesis

1981 ◽  
Vol 8 (2) ◽  
pp. 237 ◽  
Author(s):  
KSR Chapman ◽  
MD Hatch
Keyword(s):  
Zea Mays ◽  
Oxygen Evolution ◽  
Malic Enzyme ◽  
Bundle Sheath ◽  
Limited Capacity ◽  
C4 Species ◽  
Bundle Sheath Cells ◽  
C3 Photosynthesis ◽  
Mitochondrial Aspartate Aminotransferase ◽  
Sheath Cells

Strands of bundle sheath cells isolated from the NADP malic enzyme type C4 species, Zea mays, rapidly decarboxylate malate via NADP malic enzyme. The present studies show that these cells also decarboxylate aspartate, but at much lower rates. Aspartate decarboxylation is dependent upon added 2-oxoglutarate, is partially light dependent, and apparently proceeds via the following reaction sequence: aspartate ͛4 oxaloacetate ͛4 malate ͛4 pyruvate + CO2. Studies of the activity, properties, and location of enzymes indicated that these reactions are catalysed by a mitochondrial aspartate aminotransferase, mitochondrial or cytoplasmic NAD malate dehydrogenase, and chloroplast-located NADP malic enzyme, respectively. A mitochondria preparation isolated from Z. mays bundle sheath cells converted aspartate to oxaloacetate (with 2-oxoglutarate) and also pyruvate to alanine (with glutamate); the preparation did not reduce oxaloacetate to malate or decarboxylate malate at significant rates. Bundle sheath strands of Z. mays have a relatively limited capacity for HCO3- plus ribose 5-phosphate dependent oxygen evolution and rates were almost as high with aspartate plus 2-oxoglutarate. We suggest that amongst NADP malic enzyme type C4 species there may be a direct relationsip between the capacity of bundle sheath cells to decarboxylate aspartate and their potential for the photosystem II-mediated oxygen evolution.

scholarly journals The activation gate controls steady-state inactivation and recovery from inactivation in Shaker

2020 ◽  
Vol 152 (8) ◽  
Author(s):  
Tibor G. Szanto ◽  
Florina Zakany ◽  
Ferenc Papp ◽  
Zoltan Varga ◽  
Carol J. Deutsch ◽  
...  
Keyword(s):  
Steady State ◽  
Membrane Potentials ◽  
Tight Coupling ◽  
Shaker Channels ◽  
Recovery From Inactivation ◽  
Activation Gate ◽  
The Status ◽  
Steady State Inactivation

Despite major advances in the structure determination of ion channels, the sequence of molecular rearrangements at negative membrane potentials in voltage-gated potassium channels of the Shaker family remains unknown. Four major composite gating states are documented during the gating process: closed (C), open (O), open-inactivated (OI), and closed-inactivated (CI). Although many steps in the gating cycle have been clarified experimentally, the development of steady-state inactivation at negative membrane potentials and mandatory gating transitions for recovery from inactivation have not been elucidated. In this study, we exploit the biophysical properties of Shaker-IR mutants T449A/V474C and T449A/V476C to evaluate the status of the activation and inactivation gates during steady-state inactivation and upon locking the channel open with intracellular Cd2+. We conclude that at negative membrane potentials, the gating scheme of Shaker channels can be refined in two aspects. First, the most likely pathway for the development of steady-state inactivation is C→O→OI⇌CI. Second, the OI→CI transition is a prerequisite for recovery from inactivation. These findings are in accordance with the widely accepted view that tight coupling is present between the activation and C-type inactivation gates in Shaker and underscore the role of steady-state inactivation and recovery from inactivation as determinants of excitability.

A Molecular Approach to Immunoscintigraphy: A Study of the T-Antigen Conformation on the Surface of Tumors

1987 ◽  
Vol 26 (01) ◽  
pp. 1-6 ◽  
Author(s):  
S. Selvaraj ◽  
M. R. Suresh ◽  
G. McLean ◽  
D. Willans ◽  
C. Turner ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Tumor Cell ◽  
T Antigen ◽  
Human Carcinomas ◽  
Animal Tumor ◽  
Synthetic Antigens

The role of glycoconjugates in tumor cell differentiation has been well documented. We have examined the expression of the two anomers of the Thomsen-Friedenreich antigen on the surface of human, canine and murine tumor cell membranes both in vitro and in vivo. This has been accomplished through the synthesis of the disaccharide terminal residues in both a and ß configuration. Both entities were used to generate murine monoclonal antibodies which recognized the carbohydrate determinants. The determination of fine specificities of these antibodies was effected by means of cellular uptake, immunohistopathology and immunoscintigraphy. Examination of pathological specimens of human and canine tumor tissue indicated that the expressed antigen was in the β configuration. More than 89% of all human carcinomas tested expressed the antigen in the above anomeric form. The combination of synthetic antigens and monoclonal antibodies raised specifically against them provide us with invaluable tools for the study of tumor marker expression in humans and their respective animal tumor models.

On The Mechanism Of Heparin-Induced Potentiation Of Platelet Aggregation

1981 ◽  
Author(s):  
M Yamamoto ◽  
K Watanabe ◽  
Y Ando ◽  
H Iri ◽  
N Fujiyama ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Platelet Activation ◽  
Coagulation Factors ◽  
Marked Enhancement ◽  
Matrix Bound ◽  
Induced Aggregation ◽  
Aggregation Of Platelets ◽  
Plasma Heparin

It has been suggested that heparin caused potentiation of aggregation induced by ADP or epinephrine. The exact mechanism of heparin-induced platelet activation, however, remained unknown. In this paper, we have investigated the role of anti-thrombin III ( AT ) in heparin-induced platelet activation using purified AT and AT depleted plasma. When ADP or epinephrine was added to citrated PRP one minute after addition of heparin ( 1 u/ml, porcine intestinal mucosal heparin, Sigma Co. USA ), marked enhancement of platelet aggregation was observed, compared with the degree of aggregation in the absence of heparin. However, in platelet suspensions prepared in modified Tyrode’s solution, heparin exhibited no potentiating effect on platelet aggregation induced by epinephrine or ADP. Potentiation of epinephrine- or ADP-induced platelet aggregation by heparin was demonstrated when purified AT was added to platelet suspensions at a concentration of 20 μg/ml. AT depleted plasma, which was prepared by immunosorption using matrix-bound antibodies to AT, retained no AT, while determination of α1-antitrypsinα2- macroglobulin and fibrinogen in AT depleted plasma produced values which corresponded to those of the original plasma when dilution factor was taken into account. The activities of coagulation factors were also comparable to those of the original plasma. Heparin exhibited potentiating effect on ADP- or epinephrine-induced aggregation of platelets in original plasma, but no effect in AT depleted plasma. When purified AT was added back to AT depleted plasma at a concentration of 20 μg/ml, potentiation of platelet aggregation by heparin was clearly demonstrated.Our results suggest that effect of heparin on platelet aggregation is also mediated by anti-thrombin III.

ІНТЕРПРЕТАЦІЯ КАТЕГОРІЇ РОЗВИТКУ В СУЧАСНІЙ ПСИХОЛОГІЇ

1970 ◽  
Vol 8 (1) ◽  
pp. 22-30
Author(s):  
Анжеліка Шамне
Keyword(s):  
Cultural Context ◽  
Developmental Psychology ◽  
Structure And Dynamics ◽  
Modern Psychology ◽  
Development Site ◽  
Approaches To Study ◽  
Methodological Approaches ◽  
Self Motion

У статті розглянуто сучасні підходи до інтерпретації категорії розвитку, розкрито теоретичні  та методологічні підходи до вивчення категорії розвитку у сучасній психології, визначено її психологічний  зміст,   моделі,   структуру   та   динаміку.   Категорія   розвитку   розглядається   як   епіцентр   наукової  проблематики у психології та як поняття інтегративного типу. Розвиток проаналізовано як категорію,  явище і проблему психології розвитку в різних аспектах аналізу. Розглянуто місце розвитку в системі  споріднених психологічних понять. У статті також аналізуються психологічні аспекти теоретичних та  методологічних  постнекласичних  тенденцій  вивчення  природи,  характеру  та  визначення  психічного  розвитку. Постнекласична парадигма та плюралістична методологія пізнання визначають розмитість  дисциплінарної мови  та  врахування  ролі  соціокультурного  контексту  при  вивченні  психологічних явищ.  Важливими тенденціями сучасного теоретико-методологічного стану психологічних досліджень розвитку  також є визнання неефективності моністичного підходу до його вивчення, взаємозв'язок теоретичних ідей  та   спроби   створення   метатеоретичних   схем,   постнекласичне   розуміння   розвитку   як   принципово  незавершеного   процесу   саморуху,   актуалізація   антропологічного   діапазону   проблем   та   посилення  спрямованості на роль культурного контексту в дослідженні розвитку людини.  The article deals with the modern approaches to the interpretation of the category of development, reveals  the theoretical and methodological approaches to study of development in modern psychology, its psychological  content, patterns, structure and dynamics. Category of development is viewed as an epicenter of scientific issues in  modern  psychology  and  the  concept  of  the  integrative  type.  Category  of  development  is  considered  as  the  phenomenon  and  the  problem  of  developmental  psychology  in  various  aspects  of  the  analysis.  Analyzed  the  development site in the related psychological concepts. The article analyzes the psychological aspects of theoretical  and methodological postnonclassical contemporary trends in the study of nature, character, and determination of  mental  development.  Postnonclassical  paradigm  and  pluralistic  methodology  of  knowledge  determine  the  disciplinary blurring and increase of the role of the analysis of socio-cultural context in the study of psychological  phenomenon. The important tendencies of modern theoretical and methodological state of psychological researches  of development are facts of inefficiency of the monistic approach to its study, interconnection of theoretical ideas  and   attempts   of  creating   metatheoretical   schemes,   postnonclassical   understanding   of   development   as   a  fundamentally  uncompleted  process  of  self-motion,  actualization  of  anthropological  range  of  problems  and  strengthening of focus on the role of cultural context in research of human development.   

Role of the family focused technologies in the clinical course of pregnancy at women of high obstetric risk

2016 ◽  
pp. 64-66
Author(s):  
S.Yu. Vdovichenko ◽  
Keyword(s):  
Comparison Group ◽  
Traditional Approach ◽  
Married Couple ◽  
Premature Births ◽  
Individual Support ◽  
The Family ◽  
Risk Patients ◽  
Individual Preparation

The objective: to show a role of the family focused technologies in depression of frequency of pathology of pregnancy at women of high obstetric risk. Patients and methods. For determination of efficiency of prophylaxis of pathology of pregnancy on the basis of use of the family focused technologies complex clinical-psychological and laboratory and tool examination of 300 women with factors of obstetric risk which were divided into two groups was conducted. In the main group – 182 women with motivation on partner labors to which provided training on system of individual preparation of married couple to labors. The comparison group consisted of 118 women who were not in prenatal training and had individual support in childbirth, with the traditional approach to pain management. Results. Use of the family focused technologies during pregnancy allows to reduce significantly the frequency of the main complications of pregnancy, especially not incubation and premature births. Conclusion. In our opinion, the technique is simple, available and can widely be used in practical health care at women with high obstetric risk. Key words: obstetric risk, the family focused technologies, prophylaxis.

PERANAN INSPEKTORAT KABUPATENSUMENEP DALAM MENCEGAH DAN MENDETEKSI FRAUD DI DINAS PENDIDIKAN SUMENEP

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Astri Furqani ◽  
Hafidhah .
Keyword(s):  
Local Government ◽  
Qualitative Study ◽  
Asset Management ◽  
Sampling Technique ◽  
Research Data ◽  
Qualitative Approach ◽  
Primary Data ◽  
The Government

In this era, a lot of activities that can not be separated from the practice of cheating or fraud , no exception In the government . Inspektorat Sumenep is the leading institution of internal Local Government in preventing and detecting fraud in the Local Government appropiate Perbup Sumenep No. 29 of 2008 . Dinas Pendidikan Sumenep need attention on the issue . This is due to Dinas Pendidikan Sumenep an agency with the largest number of assets and managing large budgets . These conditions led to the formulation of the problem is How Inspektorat Sumenep role in preventing and detecting fraud in Dinas Pendidikan Sumenep. This study used a qualitative approach in which the focus of this study is Inspektorat role in preventing and detecting fraud at Dinas Pendidikan Sumenep . Primary data obtained by direct interviews with the parties directly related to the determination of the source of research data in a qualitative study using nonprobability sampling . The sampling technique used was purposive sampling . The conclusion of this study, role of the Inspektorat Sumenep in the prevention of fraud in Dinas Pendidikan Sumenep still not maximal . This is due to Inspektorat Sumenep not supervise from the planning / budgeting and not optimal in overseeing and assisting the implementation of the SPIP as an instrument of fraud prevention in Dinas Pendidikan Sumenep . The role of Inspektorat Sumenep in the detection of fraud in Dinas Pendidikan Sumenep done by conducting an audit of financial and asset management in each financial year.Keywords: fraud, government, inspektorat.

Sign in / Sign up

Export Citation Format

Share Document