NH4+ transport in acid-secreting insect epithelium

1988 ◽  
Vol 254 (2) ◽  
pp. R348-R356 ◽  
Author(s):  
R. B. Thomson ◽  
J. M. Thomson ◽  
J. E. Phillips
Keyword(s):  
Amino Acids ◽  
Apical Membrane ◽  
Schistocerca Gregaria ◽  
Hydrogen Ion ◽  
Ph Gradients ◽  
Ussing Chambers ◽  
Ion Secretion ◽  
Acid Secreting ◽  
Ph Range ◽  
The Relationship

The relationship between ammonia secretion (JAmm), hydrogen ion secretion (JH), and intracellular pH (pHi) was investigated in isolated locust (Schistocerca gregaria) rectal epithelia mounted as flat sheets in specially designed Ussing chambers. In the absence of exogenous CO2 and ammonia, the rectum is capable of net acid and ammonia secretion into the lumen against pH gradients of up to 1.8 U. JAmm was dependent on the presence of luminal amino acids and Na+ and it was relatively unaffected by K+ removal or changes in membrane potential. JAmm and pHi remained fairly constant over a luminal pH range of 7-5, whereas JH decreased linearly to zero over the same pH range. Mucosal addition of 1 mM amiloride reduced JAmm by 60%. This study demonstrates that the locust rectum secretes significant quantities of endogenously produced ammonia preferentially into the lumen as NH+4 rather than NH3. Moreover, the results suggest that the ammonia crosses the apical membrane via an amiloride-inhibitable Na+-NH+4 exchange mechanism.

Relation Between Hydrogen Ion Secretion and Oxygen Consumption by Ex Vivo Isolated Canine Stomach, Perfused with Homologous Blood

1972 ◽  
Vol 50 (10) ◽  
pp. 955-961 ◽  
Author(s):  
K. Kowalewski ◽  
A. Kolodej
Keyword(s):  
Oxygen Consumption ◽  
Linear Correlation ◽  
Biochemical Analysis ◽  
Ex Vivo ◽  
Hydrogen Ion ◽  
Hydrogen Ions ◽  
Homologous Blood ◽  
Method Of Least Squares ◽  
Ion Secretion ◽  
The Relationship

The relationship between oxygen consumption and acid secretion was studied in 28 totally isolated ex vivo canine stomachs, perfused extracorporeally with homologous blood. Two hundred six 30-min samples of gastric juice and blood were collected for biochemical analysis. Paired values of HCl (microequivalents per minute) and O2 consumption (micromoles per minute) were then analyzed by the method of least squares, using a computer. Linear correlation was calculated between these two values. The correlation coefficient was 0.9518 and the slope of the line was 0.512. The ratio of hydrogen ions produced to oxygen molecules consumed was 1.18 ± 0.53. The range of titratable H+ found in this study was from 0 to 833 μequiv/min and the range of O2 consumed was from 18 to 442 μmol/min.

Isoleucine Plays an Important Role for Maintaining Immune Function

2019 ◽  
Vol 20 (7) ◽  
pp. 644-651 ◽  
Author(s):  
Changsong Gu ◽  
Xiangbing Mao ◽  
Daiwen Chen ◽  
Bing Yu ◽  
Qing Yang
Keyword(s):  
Amino Acids ◽  
Acid Metabolism ◽  
Branched Chain Amino Acids ◽  
Whole Body ◽  
Immune Functions ◽  
Host Defense Peptides ◽  
Innate And Adaptive Immunity ◽  
Physiological Functions ◽  
Branched Chain ◽  
The Relationship

Branched chain amino acids are the essential nutrients for humans and many animals. As functional amino acids, they play important roles in physiological functions, including immune functions. Isoleucine, as one of the branched chain amino acids, is also critical in physiological functions of the whole body, such as growth, immunity, protein metabolism, fatty acid metabolism and glucose transportation. Isoleucine can improve the immune system, including immune organs, cells and reactive substances. Recent studies have also shown that isoleucine may induce the expression of host defense peptides (i.e., β-defensins) that can regulate host innate and adaptive immunity. In addition, isoleucine administration can restore the effect of some pathogens on the health of humans and animals via increasing the expression of β-defensins. Therefore, the present review will emphatically discuss the effect of isoleucine on immunity while summarizing the relationship between branched chain amino acids and immune functions.

Reaction of 4-chlorobenzenediazonium chloride with L-proline, sarcosine, and DL-alanine

1982 ◽  
Vol 47 (11) ◽  
pp. 2922-2926 ◽  
Author(s):  
Viktor Mejstřík ◽  
Petr Gryga ◽  
Miroslav Matrka
Keyword(s):  
Amino Acids ◽  
Ph Range

The rates of reactions of substituted phenyldiazonium salts with the title amino acids were estimated in the pH range 6.5-10.5. The reaction product of 4-chlorobenzenediazonium chloride and L-proline was isolated and its triazene structure was shown.

scholarly journals Ion Transport and the Development of Hydrogen Ion Secretion in the Stomach of the Metamorphosing Bullfrog Tadpole

1969 ◽  
Vol 54 (1) ◽  
pp. 76-95 ◽  
Author(s):  
John G. Forte ◽  
Liangchai Limlomwongse ◽  
Dinkar K. Kasbekar
Keyword(s):  
Ion Transport ◽  
Active Transport ◽  
Hydrogen Ion ◽  
Equilibrium Potential ◽  
Flux Analysis ◽  
Cell Interior ◽  
Ion Secretion ◽  
Hcl Secretion ◽  
Bullfrog Tadpole ◽  
Induced Changes

Isolated bullfrog tadpole stomachs secrete H+ by stage XXIV of metamorphosis, when tail reabsorption is nearly complete. At this stage the PD shows characteristic responses identical to those of the adult. The appearance of HCl secretion correlates well with other studies showing the morphogenesis of oxyntic cells. Prior to the development of H+ secretion tadpole stomachs maintain a PD similar in polarity and magnitude to that of the adult; i.e., secretory (S) side negative with respect to the nutrient (N) side. The interdependence with aerobic metabolism appeared to increase progressively through metamorphosis; however, glycolytic inhibitors always abolished the PD. Isotopic flux analysis showed that the transepithelial movement of Na+ was consistent with passive diffusion, whereas an active transport of Cl- from N to S was clearly indicated. Variations in [Na+], [K+], and [Cl-] in the bathing solutions induced changes consistent with the following functional description of the pre-H+-secreting tadpole stomach. (a) The S side is relatively permeable to Cl-, but not to Na+ or K+. (b) An equilibrium potential for K+ and Cl- exists at the N interface. (c) Ouabain abolishes the selective K+ permeablity at the N interface and reduces the total PD. (d) Effects of Na+ replacement by choline in the N solution become manifest only below 10–20 mM. It is concluded that prior to development of H+ secretion, the tadpole gastric PD is generated by a Cl- pump from N to S and a Na+ pump operating from the cell interior toward the N side.

Study of the relationship between free amino acids and cataract in human lenses

1984 ◽  
Vol 38 (2) ◽  
pp. 177-179 ◽  
Author(s):  
B.S. Chauhan ◽  
N.C. Desai ◽  
Ramesh Bhatnagar ◽  
S.P. Garg
Keyword(s):  
Amino Acids ◽  
Free Amino Acids ◽  
Free Amino ◽  
Human Lenses ◽  
The Relationship

A Fundamental Study of Quantitative Desulfurization of Sulfur Containing Amino Acids by Raney Nickel and its Character

1981 ◽  
Vol 36 (3) ◽  
pp. 370-374 ◽  
Author(s):  
Shinji Ohmori ◽  
Kazuko Takahashi ◽  
Mikiko Ikeda ◽  
Toshihiko Ubuka
Keyword(s):  
Amino Acids ◽  
Raney Nickel ◽  
Hydrogen Gas ◽  
Cysteic Acid ◽  
Sulfinic Acid ◽  
Fundamental Study ◽  
Homocysteic Acid ◽  
Ni Alloy ◽  
Ph Range ◽  
Sulfur Containing

Abstract The desulfurization of several naturally occurring sulfur-containing amino acids by Raney nickel was studied under various conditions. Raney nickel, which was prepared by treating Al-Ni alloy with 5 N NaOH at 60 °C for 30 min, and was not washed with water, was most active and desulfurized, in quantitative yield, methionine, homocysteine, homocystine, homocysteine sulfinic acid, S-(2-carboxy-n-propyl)-L-cysteine, cysteine, cystine, cysteine sulfinic acid and S-methylcysteine sulfoxide. Raney nickel prepared from 100 mg of Al-Ni alloy desulfurized quantitatively up to 40 μmol methionine at 60 °C for 30 min. The desulfurization occurred effectively in the pH range of 7 and 13, but not below 7. Methionine sulfone, cysteic acid, and homocysteic acid were not subject to the reaction. The Raney nickel was deactivated by H2S, and H2O2, or combustion. Desulfurization activity was not enhanced by hydrogen gas.

Cholinergic nerves mediate stress-induced intestinal transport abnormalities in Wistar-Kyoto rats

1997 ◽  
Vol 273 (2) ◽  
pp. G486-G490 ◽  
Author(s):  
P. R. Saunders ◽  
N. P. Hanssen ◽  
M. H. Perdue
Keyword(s):  
Acute Stress ◽  
Intestinal Transport ◽  
Wistar Rat ◽  
Ussing Chambers ◽  
Ion Secretion ◽  
Wistar Kyoto Rats ◽  
Release Of Acetylcholine ◽  
Rat Strain ◽  
Wistar Kyoto ◽  
Induced Changes

We have previously reported that acute stress alters intestinal transport physiology in Wistar-Kyoto rats, a stress-susceptible strain. In this study, we tested the hypothesis that the abnormalities in these rats are due to cholinergic mechanisms. Atropine- or saline-treated rats were exposed to acute restraint stress, and, subsequently, electrophysiological parameters of excised jejunal segments were assessed in Ussing chambers. Compared with the parent Wistar rat strain, Wistar-Kyoto rats demonstrated significantly greater stress-induced changes in ion secretion and permeability. The activity of cholinesterase in intestinal mucosal homogenates was significantly less in Wistar-Kyoto than in Wistar rats. Atropine pretreatment of rats before stress corrected the epithelial pathophysiology. Our results suggest that stress stimulated the release of acetylcholine, resulting in altered epithelial function in these genetically predisposed rats.

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