scholarly journals Correlation between Ca2+ uptake, Ca2+ efflux and phosphoenzyme level in sarcoplasmic-reticulum vesicles

1991 ◽  
Vol 274 (2) ◽  
pp. 427-432 ◽  
Author(s):  
J C Benech ◽  
A Galina ◽  
L de Meis
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Aqueous Medium ◽  
Atp Synthesis ◽  
Dimethyl Sulphoxide ◽  
The Other ◽  
Apparent Affinity ◽  
High Affinity ◽  
Ph Values ◽  
A Value ◽  
Other Hand

Previously [Inesi & de Meis (1989) J. Biol. Chem. 264, 5929-5936] it was shown that dimethyl sulphoxide (Me2SO) increases the amount of Ca2+ accumulated by sarcoplasmic-reticulum vesicles. This effect was related to a decrease in the enzyme affinity for ADP from less than 20 microM to 1 mM. In the present work the apparent affinity of the ADP-sensitive phosphoenzyme for ADP was determined by measuring the rate of ATP synthesis in vesicles previously loaded with Ca2+, at different pH values and in the presence and absence of Me2SO (20%, v/v) and KCl. In all conditions tested, addition of Me2SO never promoted an increase of the apparent Km for ADP to a value higher than 25 microM. ADP inhibits the phosphorylation of the enzyme by Pi. Two components, with Ki values of 80 microM and 8 mM, were detected when vesicles previously loaded with Ca2+ were used. The high-affinity component (Ki 80 microM) was abolished after addition of Me2SO to the medium. Empty vesicles, on the other hand, exhibited only the low-affinity component (Ki 8 mM). During ATP synthesis in a totally aqueous medium, there was a decrease in the phosphoenzyme formed by Pi, after addition of 80-100 microM-ADP to the medium. In the presence of Me2SO this decrease was smaller. The sum of the fractions of phosphoenzyme formed by ATP and by Pi during Ca2+ uptake was higher in the presence of Me2SO than in a totally aqueous medium. Me2SO decreased the passive efflux of Ca2+ measured in the presence of 0.1 mM-Pi and 0.1 mM-MgCl2. In a totally aqueous medium the same decrease was observed when Pi and MgCl2 concentrations were raised to 4 mM. These data suggest that ADP binds to two different enzyme conformations. The binding to one of these conformations (*E) inhibits the phosphorylation of the enzyme by Pi, increases the efflux of Ca2+ and decreases the amount of Ca2+ accumulated by the vesicles.

NaCl-dependent expression of amiloride-blockable Na+ channel in Xenopus oocytes

1992 ◽  
Vol 262 (2) ◽  
pp. G244-G248 ◽  
Author(s):  
C. Asher ◽  
D. Singer ◽  
R. Eren ◽  
O. Yeger ◽  
N. Dascal ◽  
...  
Keyword(s):  
Xenopus Oocytes ◽  
The Other ◽  
Na Channel ◽  
Channel Activity ◽  
High Affinity ◽  
Other Hand ◽  
Exogenous Rna ◽  
Lower Intestine ◽  
Regulation Of Transport

RNA was isolated from chicken lower intestine (both colon and coprodeum) and injected into Xenopus oocytes. 22Na+ fluxes measured after 1-4 days demonstrated the induction of an amiloride-blockable pathway. The Na+ transporter expressed by the exogenous RNA had a high affinity to amiloride (inhibitory constant less than 0.1 microM), but was insensitive to ethylisopropyl amiloride, i.e., it is likely to be the apical Na+ channel. Functional channels were readily expressed in oocytes injected with RNA derived from chickens fed a low-NaCl diet. On the other hand, no channel activity was detected in oocytes injected with RNA isolated from chickens fed a high-NaCl diet. Thus the previously reported regulation of transport by the dietary NaCl intake involves modulations in the level of mRNA that codes either for the Na+ channel or a posttranscriptional regulator of the channel.

Unusual spectral shifts in the prototropic reactions of 2,7-diaminofluorene

1987 ◽  
Vol 65 (9) ◽  
pp. 2013-2018 ◽  
Author(s):  
R. Manoharan ◽  
Sneh K. Dogra
Keyword(s):  
Absorption Spectrum ◽  
Aqueous Medium ◽  
Fluorescence Spectrum ◽  
Blue Shift ◽  
Proton Donor ◽  
Red Shift ◽  
The Other ◽  
Spectral Shifts ◽  
Other Hand

The red shift observed in the absorption spectrum of 2,7-diaminofluorene (DAF) in ether and acetonitrile is either due to the proton-donating capacity of the solute or due to its dispersive interactions with the solvent and a blue shift in methanol and water is due to the proton-accepting nature of DAF. DAF acts as a proton donor in S1 state in all solvents. The red shift in the fluorescence spectrum of the monocation of DAF relative to that of DAF is not because of the —NH2 group becoming more basic but because of the large solvent relaxating in aqueous medium. On the other hand, the monocation of DAF in cyclohexane follows the normal blue shift in the fluorescence spectrum. pKa values for the various prototropic reactions in S0 and S1 states are determined and discussed.

Inhibition of Oxygen Evolution by Cacalol and Its Derivatives

1991 ◽  
Vol 46 (9-10) ◽  
pp. 777-780 ◽  
Author(s):  
B. Lotina-Hennsen ◽  
J. L. Roque-Reséndiz ◽  
M. Jiménez ◽  
M. Aguilar
Keyword(s):  
Electron Transport ◽  
Oxygen Evolution ◽  
Photosystem I ◽  
Atp Synthesis ◽  
The Other ◽  
Other Hand ◽  
Transport Inhibitors ◽  
Proton Uptake

Abstract The inhibition of ATP synthesis, proton uptake and electron transport (basal, phosphory-lating and uncoupled) from water to methylviologen indicates that cacalol and its derivatives act as electron transport inhibitors. Since on one hand photosystem I is not affected and elec­tron transport from DPC to QA is midly affected and on the other hand the electron transport from water to DCIP, and water to silicomolibdate are inhibited, we conclude that the site of inhibition of cacalol is located at the oxygen evolution level. Cacalol derivatives inhibit elec­tron flow between P680 to QA and probably also the QB site.

scholarly journals Immigration, Humanity, and Morality

2019 ◽  
Vol 2 (1) ◽  
pp. 21-33 ◽  
Author(s):  
Sunday Adeniyi Fasoro
Keyword(s):  
Political Theory ◽  
The Other ◽  
Moral Principles ◽  
A Value ◽  
The Earth ◽  
Other Hand ◽  
Common Ownership ◽  
Vulnerable People ◽  
The Common ◽  
The One

AbstractThe trend toward the concept of humanity in political theory has arisen largely as a reaction against the mistreatment of vulnerable people such as immigrants. The issue of immigrants’ vulnerability has led political thinkers to ponder on how to apply the principle of humanity to the question of the treatment of immigrants. I would like to address this matter by examining two questions: what is humanity, is it a value property, or a virtue? Does it really matter if the means by which an immigrant immigrates is demeaning to his own humanity as a person? The most common or intuitive reply to these questions would probably be: ‘humanity’ is simply a value-bestowing property, so regardless of immigrants’ actions they are owed respectful treatment. The aim of this paper is to emphasise instead that ‘humanity’ should be conceived as a virtue of actual commitment to act on moral principles. I explore three different meanings of humanity. First, I discuss ‘humanity’ as the common ownership of the earth. Second, I discuss ‘humanity’ as a value property. Third, I discuss humanity as a virtue of acting, on the one hand, with humanity, and on the other hand, on moral principles.

scholarly journals Predominant androgenic component in the stimulatory effect of dehydroepiandrosterone on bone mineral density in the rat

1998 ◽  
Vol 157 (3) ◽  
pp. 433-442 ◽  
Author(s):  
C Martel ◽  
A Sourla ◽  
G Pelletier ◽  
C Labrie ◽  
M Fournier ◽  
...  
Keyword(s):  
Trabecular Bone ◽  
Bone Mineral ◽  
Bone Volume ◽  
The Other ◽  
Female Rats ◽  
Trabecular Bone Volume ◽  
A Value ◽  
Other Hand ◽  
Dhea Treatment ◽  
Trabecular Number

In order to assess the relative roles of the androgenic and/or estrogenic components in the stimulatory effect of dehydroepiandrosterone (DHEA) on bone mineral content (BMC) and density (BMD), ovariectomized (OVX) female rats received DHEA administered alone or in combination with the antiandrogen flutamide (FLU) or the antiestrogen EM-800 for 12 months. We also evaluated, for comparison, the effect of estradiol (E2) and dihydrotestosterone (DHT) constantly released by Silastic implants as well as medroxyprogesterone acetate (MPA) released from poly(lactide-co-glycolide) microspheres. Femoral BMD was decreased by 11% 1 year after OVX, but treatment of OVX animals with DHEA increased BMD to a value 8% above that of intact animals. The administration of FLU reversed by 76% the stimulatory effect of DHEA on femoral BMD and completely prevented the stimulatory effect of DHEA on total body and lumbar spine BMD. Similar results were obtained for BMC. On the other hand, treatment with the antiestrogen EM-800 did not reduce the action of DHEA on BMD or BMC. At the doses used, MPA, E2 and DHT increased femoral BMD, but to a lesser degree than observed with DHEA. Bone histomorphometry measurements were also performed. While DHEA treatment partially reversed the marked inhibitory effect of OVX on the tibial trabecular bone volume, the administration of FLU inhibited by 51% (P < 0.01) the stimulatory effect of DHEA on this parameter. The addition of EM-800 to DHEA, on the other hand, increased trabecular bone volume to a value similar to that of intact controls. DHEA administration markedly increased trabecular number while causing a marked decrease in the intertrabecular area. The above stimulatory effect of DHEA on trabecular number was reversed by 54% (P < 0.01) by the administration of FLU, which also reversed by 29% the decrease in intertrabecular area caused by DHEA administration. On the other hand, the addition of EM-800, while further decreasing the intertrabecular space achieved by DHEA treatment, also led to a further increase in trabecular number to a value not significantly different from that of intact control animals, suggesting an additional effect of EM-800 over that achieved by DHEA. Treatment with DHEA caused a 4-fold stimulation of serum alkaline phosphatase, a marker of bone formation, while the urinary excretion of hydroxyproline, a marker of bone resorption, was decreased by DHEA treatment. Treatment with DHEA and DHEA + EM-800 decreased serum cholesterol levels by 22 and 65% respectively, while the other treatments had no significant effect on this parameter. The present data indicate that the potent stimulatory effect of DHEA on bone in the rat is mainly due to the local formation of androgens in bone cells and their intracrine action in osteoblasts.

scholarly journals EVIDENCE FOR A PHOTON MASS

2010 ◽  
Vol 19 (07) ◽  
pp. 1341-1347 ◽  
Author(s):  
B. G. SIDHARTH
Keyword(s):  
Power Spectrum ◽  
Gamma Rays ◽  
Time Lag ◽  
The Other ◽  
Photon Mass ◽  
The Past ◽  
A Value ◽  
Other Hand ◽  
Wmap Data

Recently Spavieri and Rodriguez had proposed a table top experiment using Aharanov–Bohm type effects to determine the mass of a photon and concluded that a value as small as 10-51 g is achievable. It is pointed out in this paper that this value is already much higher than latest experimental limits. Furthermore, the author's work over the past years has, on the other hand, indicated that the photon has a mass ~10-65 g = 10-33 eV . We point out in this papers that recent observations from three different viewpoints, which are not table top experiments, but rather the time lag in cosmic gamma rays with different frequencies, the observation of the spectra of blazars and an analysis of the CMB power spectrum from the WMAP data, all vindicate this conclusion and remarkably, this value.

scholarly journals SISTEM NILAI PELA SEBAGAI MODAL SOSIAL DALAM RANGKA PENGUATAN KEBANGSAAN PADA BASIS LOKAL DI MALUKU

2020 ◽  
Vol 2 (1) ◽  
pp. 11-28
Author(s):  
Max Maswekan
Keyword(s):  
Social Capital ◽  
Social Cohesion ◽  
Social System ◽  
Regional Level ◽  
The Other ◽  
Potential Conflict ◽  
Value System ◽  
A Value ◽  
Other Hand ◽  
The One

Indonesia is a pluralistic country (diverse) in terms of ethnicity, religion, culture, language and social system. This diversity is a blessing that is given as a potential wealth of the nation. On the one hand, this potential can be managed to strengthen nationality and people's welfare, but on the other hand, it can be a potential conflict that can weaken and even solve (disintegration) of nationalism if it is not managed properly. Indonesia has a variety of local wisdom as invaluable social capital. One of them is Pela in Maluku which has a value system that is capable of marching and strengthening (integration) nationalism. The Pela value system has at least four functions that are able to effectively integrate (social cohesion) and strengthen national potential at the local (regional) level, especially in Maluku.

Definition of Specific Impulse

1954 ◽  
Vol 58 (526) ◽  
pp. 728-728 ◽  
Author(s):  
F. W. Thorne
Keyword(s):  
Specific Impulse ◽  
The Other ◽  
A Value ◽  
Other Hand ◽  
Definition Of ◽  
Mass Definition

Your contributors on Specific Impulse in the May journal say, “ The mass definition, on the other hand, gives a value of specific impulse which varies according to the units used.“It must be realised that the value of a quantity cannot depend on the units chosen. To quote therefore the example on page 371 in gravitational units, namely: —

Can we Modify our Pleasures? A New Look at Kant on Pleasure in the Agreeable

2020 ◽  
Vol 25 (3) ◽  
pp. 365-388
Author(s):  
Erica A. Holberg
Keyword(s):  
Moral Values ◽  
Sharp Contrast ◽  
The Other ◽  
Moral Law ◽  
A Value ◽  
Other Hand ◽  
Moral Judgements ◽  
Realistic View ◽  
The One ◽  
Rational Direction

AbstractMany of us are all too familiar with the experience of taking pleasure in things we feel we ought not, and of finding it frustratingly hard to bring our pleasures into line with our moral judgements. As a value dualist, Kant draws a sharp contrast between the two sources of practical motivation: pleasure in the agreeable and respect for the moral law. His ethics might thus seem to be an unpromising source for help in thinking about how we can bring our agreeable pleasures into line with our moral values. But I argue that a careful reading of Kant’s texts reveals a helpfully realistic view about the extent to which we can modify our agreeable pleasures. On my interpretation, Kant shows us how to hold together two seemingly incompatible ideas: on the one hand, that pleasure in the agreeable is resistant to rational direction, and on the other hand, that we can cultivate these pleasures with a view to ethical self-transformation.

A note on measurements of Onsager coefficients in maple petioles and maple woody xylem by electroosmotic techniques

1970 ◽  
Vol 48 (6) ◽  
pp. 1289-1292 ◽  
Author(s):  
D. J. Ursino ◽  
D. S. Fensom
Keyword(s):  
Acer Saccharum ◽  
Specific Conductivity ◽  
Growing Season ◽  
Phloem Transport ◽  
The Other ◽  
Plant Tissues ◽  
A Value ◽  
Other Hand

Measurements on petioles and on 2- and 4-year old xylem of Acer saccharum have shown that the specific conductivity (LEE) measured after they were soaked in 10−4 N KCl was about 2 × 10−4 ohm−1 cm−1 and did not change significantly through the growing season in these plant tissues. On the other hand the electrokinetic coefficient (LPE) varied seasonally in the petioles with a value of about 3 × 10−6 in spring and 3 × 10−5 cm2 s−1 volt−1 in summer. The electrokinetic coefficient in the woody xylem measured about 6 × 10−5 cm2 s−1 volt−1. From the values of these Onsager coefficients the contribution of electroosmosis to phloem transport would seem to be negligible in these cut sections.

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