Acid-base effects on intestinal Na+ absorption and vesicular trafficking

2002 ◽  
Vol 283 (3) ◽  
pp. C971-C979 ◽  
Author(s):  
Alan N. Charney ◽  
Richard W. Egnor ◽  
Jesline Alexander-Chacko ◽  
Nicholas Cassai ◽  
Gurdip S. Sidhu
Keyword(s):  
Electron Microscopy ◽  
Apical Membrane ◽  
Ringer Solution ◽  
Vesicular Trafficking ◽  
Acid Base ◽  
Western Blots ◽  
Ph Values ◽  
Transmission Electron ◽  
Apical Membranes ◽  
Nhe Isoforms

We examined for vesicular trafficking of the Na+/H+ exchanger (NHE) in pH-stimulated ileal and CO2-stimulated colonic Na+absorption. Subapical vesicles in rat distal ileum were quantified by transmission electron microscopy at ×27,500 magnification. Internalization of ileal apical membranes labeled with FITC-phytohemagglutinin was assessed using confocal microscopy, and pH-stimulated ileal Na+ absorption was measured after exposure to wortmannin. Apical membrane protein biotinylation of ileal and colonic segments and Western blots of recovered proteins were performed. In ileal epithelial cells incubated in HCO[Formula: see text]/Ringer or HEPES/Ringer solution, the number of subapical vesicles, the relative quantity of apical membrane NHE isoforms 2 and 3 (NHE2 and NHE3, respectively), and apical membrane fluorescence under the confocal microscope were not affected by pH values between 7.1 and 7.6. Wortmannin did not inhibit pH-stimulated ileal Na+ absorption. In colonic epithelial apical membranes, NHE3 protein content was greater at a Pco 2 value of 70 than 21 mmHg, was internalized when Pco 2 was reduced, and was exocytosed when Pco 2 was increased. We conclude that vesicle trafficking plays no part in pH-stimulated ileal Na+absorption but is important in CO2-stimulated colonic Na+ absorption.

Acid-base effects on intestinal Cl- absorption and vesicular trafficking

2004 ◽  
Vol 286 (5) ◽  
pp. C1062-C1070 ◽  
Author(s):  
Alan N. Charney ◽  
Richard W. Egnor ◽  
David Henner ◽  
Haroon Rashid ◽  
Nicholas Cassai ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Anion Exchanger ◽  
Apical Membrane ◽  
Ussing Chamber ◽  
Vesicular Trafficking ◽  
Acid Base ◽  
Western Blots ◽  
Rat Ileum ◽  
Apical Membranes ◽  
Type 3

In rat ileum and colon, apical membrane [Formula: see text] exchange and net Cl- absorption are stimulated by increases in Pco2 or [Formula: see text]. Because changes in Pco2 stimulate colonic Na+ absorption, in part, by modulating vesicular trafficking of the Na+/H+ exchanger type 3 isoform to and from the apical membrane, we examined whether changes in Pco2 affect net Cl- absorption by modulating vesicular trafficking of the [Formula: see text] exchanger anion exchanger (AE)1. Cl- transport across rat distal ileum and colon was measured in the Ussing chamber, and apical membrane protein biotinylation of these segments and Western blots of recovered proteins were performed. In colonic epithelial apical membranes, AE1 protein content was greater at Pco2 70 mmHg than at Pco2 21 mmHg but was not affected by pH changes in the absence of CO2. AE1 was internalized when Pco2 was reduced and exocytosed when Pco2 was increased, and both mucosal wortmannin and methazolamide inhibited exocytosis. Wortmannin also inhibited the increase in colonic Cl- absorption caused by an increase in Pco2. Increases in Pco2 stimulated ileal Cl- absorption, but wortmannin was without effect. Ileal epithelial apical membrane AE1 content was not affected by Pco2. We conclude that CO2 modulation of colonic, but not ileal, Cl- absorption involves effects on vesicular trafficking of AE1.

Changes in Size of Casein Micelles Caused by Growth of Psychrotrophic Bacteria in Raw Skim Milk

1984 ◽  
Vol 47 (1) ◽  
pp. 16-19 ◽  
Author(s):  
JONATHAN P. BURLINGAME-FREY ◽  
ELMER H. MARTH
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Skim Milk ◽  
Bacterial Activity ◽  
Casein Micelles ◽  
Psychrotrophic Bacteria ◽  
Ph Values ◽  
Psychrotrophic Bacterium ◽  
Transmission Electron

Raw skim milk was inoculated (1%, v/v) with a proteolytic psychrotrophic bacterium that previously was isolated from milk. The inoculated skim milk was incubated at 7°C for 0, 3, 5 and 7 d. The pH values for the milk were 6.6, 6.5, 6.45 and 5.95, and the numbers of psychrotrophs/ml were 1.0 × 104 8.9 × 107, 9.0 × 108 and 2.5 × 108 for days 0, 3, 5 and 7, respectively. Samples of milk were negatively stained, examined with transmission electron microscopy and distribution of sizes of casein micelles was determined. The average and (mode) sizes of micelles were 849 (789), 1030 (634), 761 (634) and 405 (316) Angstroms for milks after days 0, 3, 5 and 7, respectively. Another set of samples was prepared from skim milk immediately after it was acidified to pH values of 6.6, 6.5, 6.45 and 5.95. The average and (mode) sizes of micelles were 891 (766), 875 (615), 913 (766) and 840 (615) Angstroms for milks having pH values of 6.6, 6.5, 6.45 and 5.95, respectively. Changes in size of micelles in the incubated samples resulted from bacterial activity other than small changes in pH.

Ultrastructural observations of the tegument of Postorchigenes gymnesicus (Digenea: Lecithodendriidae)

1996 ◽  
Vol 70 (1) ◽  
pp. 13-19 ◽  
Author(s):  
J.R. Ferrer ◽  
M. Gracenea ◽  
M. Trullols ◽  
O. Gonzalez-Moreno
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Protein Content ◽  
Basal Lamina ◽  
Apical Membrane ◽  
General Body ◽  
Body Regions ◽  
Transmission Electron ◽  
Direct Association

AbstractThe tegument of Postorchigenes gymnesicus has been studied by scanning and transmission electron microscopy. The general body tegument is spinous and contains mitochondria, biconcave disc-shaped vesicles bounded by an unitary membrane and displaying a protein content, and scarce spherical bodies. The tegument covering specialized body regions is aspinous. Few vesicles were evident in the tegument covering the suckers and oesophagus, being more abundant in the metraterm and cirrus where the tegument is thicker. Laurer's canal has a thick tegument with sparse vesicles, mostly arranged close to the apical membrane. A direct association was evident between the basal lamina underlying the spines and the muscular subtegumental fibres, suggesting a motile character for the spine.

cAMP-induced changes of apical membrane potentials of confluent H441 monolayers

2003 ◽  
Vol 285 (2) ◽  
pp. L443-L450 ◽  
Author(s):  
Ahmed Lazrak ◽  
Sadis Matalon
Keyword(s):  
Apical Membrane ◽  
Ringer Solution ◽  
Membrane Potentials ◽  
Open Probability ◽  
Open Time ◽  
Current Clamp Mode ◽  
Apical Membranes ◽  
Induced Changes ◽  
Human Lung Cell Line ◽  
Lung Cell Line

We recorded apical membrane potentials ( Va) of H441 cells [a human lung cell line exhibiting both epithelial Na+ (ENaC) and CFTR-type channels] grown as confluent monolayers, using the microelectrode technique in current-clamp mode before, during, and after perfusion of the apical membranes with 10 μM forskolin. When perfused with normal Ringer solution, the cells had a Va of -43 ± 10 mV (means ± SD; n = 31). Perfusion with forskolin resulted in sustained depolarization by 25.0 ± 3.5 mV (means ± SD; n = 23) and increased the number, open time, and the open probability of a 4.2-pS ENaC. In contrast to a previous report (Jiang J, Song C, Koller BH, Matthay MA, and Verkman AS. Am J Physiol Cell Physiol 275: C1610–C1620, 1998), no transient hyperpolarization was observed. The forskolin-induced depolarization of Va was almost totally prevented by pretreatment of monolayers with 10 μM amiloride or by substitution of Na+ ions in the bath solution with N-methyl-d-glucamine. These findings indicate that cAMP stimulation of Na+ influx across H441 confluent monolayers results from activation of an amiloride-sensitive apical Na+ conductance and not from Va hyperpolarization due to Cl- influx through CFTR-type channels.

Practicably efficient ethylbenzene oxidation catalyzed by manganese tetrakis(4-sulfonatophenyl)porphyrin grafted to powdered chitosan

2018 ◽  
Vol 22 (06) ◽  
pp. 481-490 ◽  
Author(s):  
Guan Huang ◽  
Chao Yan ◽  
Jing Li Cai ◽  
Lin Qiang Mo ◽  
Shu Kai Zhao ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Oxidation Reactions ◽  
Amino Groups ◽  
Visible Spectroscopy ◽  
Acid Base ◽  
Ethylbenzene Oxidation ◽  
X Ray ◽  
Phenethyl Alcohol ◽  
Transmission Electron

Manganese tetrakis(4-sulfonatophenyl)porphyrin chloride was grafted onto powdered chitosan via an acid–base reaction and ligation. The grafted catalyst was characterized by transmission electron microscopy, ultraviolet and visible spectroscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectrometry and thermogravimetry. Ethylbenzene oxidation with O[Formula: see text] by the catalyst in the absence of additives and solvents can achieve moderate yields (approximately 30%) of acetophenone and phenethyl alcohol. The grafted catalyst can be reused four times for oxidation reactions. The results indicate that the catalytic activity of manganese tetrakis(4-sulfonatophenyl)porphyrin chloride is promoted by the ligation and grafting function of the amino groups in the powdered chitosan.

scholarly journals Immunolocalization of proton pumps (H+-ATPase) in pavement cells of rainbow trout gill

1995 ◽  
Vol 198 (12) ◽  
pp. 2619-2629 ◽  
Author(s):  
G Sullivan ◽  
J Fryer ◽  
S Perry
Keyword(s):  
Electron Microscopy ◽  
Rainbow Trout ◽  
Epithelial Cells ◽  
Apical Membrane ◽  
Respiratory Acidosis ◽  
Proton Pumps ◽  
Ion Regulation ◽  
Western Blots ◽  
Pavement Cells ◽  
Trout Gill

The expression of the V-type proton ATPase (H+-ATPase) was examined in the gill of the freshwater rainbow trout (Oncorhynchus mykiss) using immunocytochemistry in concert with laser scanning confocal or electron microscopy. A synthetic peptide consisting of the carboxy-terminal region of the 31 kDa subunit of the bovine renal H+-ATPase was used to generate an antiserum in rabbits, and its suitability for use in trout gill was confirmed by western blotting. Gill epithelial cells demonstrated specific immunoreactivity, the intensity of which was increased markedly after 18 h of exposure to hypercapnia (1 % CO2 in air). The increased intensity of H+-ATPase immunoreactivity was associated with elevated branchial net acid excretion. In the hypercapnic fish, the specific immunoreactivity was associated with both the apical membrane and cytoplasm. Electron microscopy revealed that specific immunoreactivity was localized to the pavement cells and was particularly associated with the apical membrane and subapical cytoplasmic vesicles. The increased H+-ATPase immunoreactivity in the epithelial cells of hypercapnic fish and the increased intensity of the immunoreactive bands in western blots from hypercapnic fish demonstrate an 'up-regulation' of this protein in response to respiratory acidosis. The results are discussed with reference to current models of acid­base and ion regulation in the gill of freshwater fish.

Immunocytochemical characterization of the high-affinity thiazide diuretic receptor in rabbit renal cortex

1993 ◽  
Vol 264 (1) ◽  
pp. F141-F148 ◽  
Author(s):  
D. H. Ellison ◽  
D. Biemesderfer ◽  
J. Morrisey ◽  
J. Lauring ◽  
G. V. Desir
Keyword(s):  
Thiazide Diuretic ◽  
Apical Membrane ◽  
Distal Tubule ◽  
Rabbit Kidney ◽  
Kidney Cortex ◽  
Thick Ascending Limb ◽  
Western Blots ◽  
Intense Staining ◽  
High Affinity ◽  
Apical Membranes

Thiazide diuretics increase urinary NaCl excretion primarily by inhibiting Na and Cl transport across the apical membrane of cells in the renal distal tubule. Although these diuretics bind to a membrane protein that couples transport of Na and Cl directly, the molecular nature of this transporter and its localization in the mammalian kidney remain controversial. The present experiments were designed to develop monoclonal antibodies to the high-affinity thiazide diuretic receptor to investigate its molecular characteristics and its cellular and subcellular localization in rabbit kidney. Mice were immunized with high-affinity thiazide diuretic receptors that had been partially purified from rabbit kidney cortex. Resulting hybridomas were screened for the ability to immunoprecipitate thiazide diuretic receptors that were labeled with the thiazide-like diuretic [3H]metolazone. A single hybridoma (MAb JM5) produced antibodies capable of immunoprecipitating up to 80% of the labeled thiazide receptors from solubilized renal cortical membranes. MAb JM5 reacted with a 125-kDa protein on Western blots of solubilized renal cortical apical membranes. It stained the apical membrane of cells in the distal convoluted and connecting tubule but did not stain proximal tubules, glomeruli, or interstitial structures. Less intense staining of apical membranes of principal cells in the collecting tubule and a subpopulation of cells in the thick ascending limb were also present. These results indicate that the high-affinity thiazide diuretic receptor comprises a 125-kDa protein that localizes to the apical membrane of cells in the renal distal tubule.

Characteration of Protein Loaded Chitosan Nanoparticles at Different pH Values

2011 ◽  
Vol 284-286 ◽  
pp. 950-953 ◽  
Author(s):  
Yong Liu ◽  
Yan Sun ◽  
Yan Li Li ◽  
Shao Chun Xu ◽  
Yao Xing Xu
Keyword(s):  
Electron Microscopy ◽  
Encapsulation Efficiency ◽  
Ph Value ◽  
Sodium Tripolyphosphate ◽  
Shape Change ◽  
Chitosan Nanoparticles ◽  
Positive Potential ◽  
Zeta Potentials ◽  
Ph Values ◽  
Transmission Electron

In this paper, the properties of chitosan (CS) nanoparticles (CS NPs) and Bovine Serum Albumin (BSA) loaded chitosan nanoparticles (BSA-loaded CS NPs) prepared with sodium tripolyphosphate (TPP) at different pH values were discussed. In addition, BSA encapsulation efficiency, zeta potentials and size of CS NPs and BSA-loaded CS NPs were characterized. The results indicated that sizes of CS NPs presented “V” change along with increase of pH values, while the size of BSA-loaded CS NPs showed “U” shape change. BSA encapsulation efficiency reached the biggest value when the pH value was 5.5. Zeta potentials of CS NPs and BSA-loaded CS NPs kept going down when the pH values were increasing, and positive potential of CS-loaded BSA CS NPs became higher than that of CS NPS when the pH value was more than 5.5. BSA-loaded CS NPs prepared at pH 5.5 exhibited regular and close to spherical in shape under transmission electron microscopy (TEM) sight.

scholarly journals Oxalic Acid-Assisted Hydrothermal Synthesis and Luminescent of Hexagonal NaYF4:Ln3+ (Ln = Sm, Eu, Yb/Er) Micro/Nanoplates

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Feng Tao ◽  
Zhishun Shen ◽  
Zhijun Wang ◽  
Da Shu ◽  
Qi Liu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Oxalic Acid ◽  
Molar Ratio ◽  
Photoluminescence Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ph Values ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Display Systems

Hexagonal NaYF4:Ln3+ micro/nanoplates were successfully synthesized via a hydrothermal method using oxalic acid as a shape modifier. X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and selected area electron diffraction (SAED) have been used to study the morphologies and crystal structure of the products. The effects of the pH values and the molar ratio of oxalic acid to NaOH on the crystal growth have been investigated in detail. The time-dependent experiments have been conducted to investigate the morphology evolution process, and based on the results, a possible growth mechanism was proposed. The photoluminescence properties of 5 mol% Eu3+ and 3 mol% Sm3+ doped NaYF4 and 20 mol% Yb3+/2 mol% Er3+ codoped NaYF4 micro/nanoplates were investigated. The experimental results showed that NaYF4:Ln3+ micro/nanoplates have excellent luminescence and can be potential application in the field of light display systems, lasers, and optoelectronic devices.

scholarly journals Hormonal control of apical membrane Na transport in epithelia. Studies with fluctuation analysis.

1983 ◽  
Vol 82 (2) ◽  
pp. 201-220 ◽  
Author(s):  
S I Helman ◽  
T C Cox ◽  
W Van Driessche
Keyword(s):  
Single Channel ◽  
Apical Membrane ◽  
Ringer Solution ◽  
Hormonal Control ◽  
Fluctuation Analysis ◽  
Noise Power ◽  
Na Current ◽  
Na Transport ◽  
Electrically Conductive ◽  
Apical Membranes

To study the mechanisms by which antidiuretic hormone and prostaglandins regulate Na transport at the apical membranes of the cells of anuran tissues, studies were done with fluctuation analysis. Epithelia of frog skin (Rana pipiens) were treated with vasopressin alone, or treated with vasopressin after inhibition of Na transport by indomethacin. The tissues were bathed symmetrically with a Cl-HCO3 Ringer solution and short-circuited continuously. In this experimental circumstance, the amiloride-induced current noise power density spectra were of the Lorentzian type with little or no l/f noise, provided that "scraped" skins were used for study. Despite large changes of Na transport, especially in epithelia treated with indomethacin and vasopressin, the single-channel Na current remained essentially unchanged, whereas the density of amiloride-inhibitable, electrically conductive Na channels was increased by vasopressin and decreased by indomethacin.

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