scholarly journals Electron probe analysis of calcium transport by small intestine.

1975 ◽  
Vol 64 (1) ◽  
pp. 54-74 ◽  
Author(s):  
R R Warner ◽  
J R Coleman
Keyword(s):  
Small Intestine ◽  
Goblet Cell ◽  
Calcium Transport ◽  
Electron Probe ◽  
Cellular Level ◽  
Electron Probe Analysis ◽  
In Transit ◽  
Vitamin D Depletion ◽  
Cell Mucus

Calcium transport in small intestine of rat and chick has been studied at the cellular level using the electron probe X-ray microanalyzer. Tissues were examined directly after removal as well as after incubation in a calcium solution. In both preparations, discrete calcium localizations were found associated with intracellular and extracellular goblet cell mucus. The in vitro preparations showed calcium in transit across the absorptive epithelium in discrete localizations. Although the primary path of transport was along lateral cell borders, some localizations were found in the cytoplasm in a supranuclear position. The effect of vitamin D depletion and repletion was to decrease and increase, respectively, the number of calcium localizations in transit across the epithelium. These results suggest that calcium is transported while in a sequestered form and indicate that goblet cell mucus plays a role in this transport process.

Electron probe X-ray microanalysis of the effects of Bacillus thuringiensis var kurstaki crystal protein insecticide on ions in an electrogenic K+-transporting epithelium of the larval midgut in the lepidopteran, Manduca sexta, in vitro

1985 ◽  
Vol 74 (1) ◽  
pp. 137-152
Author(s):  
B.L. Gupta ◽  
J.A. Dow ◽  
T.A. Hall ◽  
W.R. Harvey
Keyword(s):  
Bacillus Thuringiensis ◽  
Manduca Sexta ◽  
Goblet Cell ◽  
Electron Probe ◽  
Apical Membrane ◽  
Short Circuit ◽  
Short Circuit Current ◽  
X Ray ◽  
Elemental Concentrations

An alkaline hydrolysate of Bacillus thuringiensis var kurstaki HD1 (Btk) parasporal crystals was administered at 25 micrograms ml-1 (f.c.) to isolated, short-circuited, midguts of tobacco hornworm (Manduca sexta) larvae. The short-circuit current (s.c.c.), a precise measure of K+ active transport, was inhibited by 78% in 10 min in Btk-treated midguts as compared to controls. The elemental concentrations of K, together with Na, Mg, P, S, Cl and Ca, as well as the water content, were determined by electron probe X-ray microanalysis (EPXMA) in the muscle cells, columnar cells and goblet cells, as well as in the extracellular goblet cavity and the bathing media. The average K concentration in the goblet cell cavity was 129 mmol/kg wet wt in control midguts but only 37 mmol/kg wet wt in Btk-treated midguts. The elemental concentrations, including that of K, in other cell compartments were much less affected by Btk, but a rise in total cell calcium is suggested. It has been previously suggested that in vitro Btk acts specifically on limited regions of the apical membrane of the midgut epithelial cells. The simplest interpretation of the EPXMA results would be that initially Btk interacts specifically with the goblet cell apical membrane, which bounds the goblet cavity and contains the K+ pump responsible for the s.c.c. and high transepithelial potential difference (p.d.). Such interaction results in a rapid disruption of K+ transport across the goblet cell apical membrane, leading to dissipation of the K+ gradient and loss of p.d. The histopathological changes previously reported by other workers would then be a consequence of K+ pump inhibition causing changes in the intracellular pH, Ca2+ etc. Some possible molecular bases for these specific interactions between Btk and cell membrane are discussed.

Intestinal calcium transport in the spontaneously hypertensive rat: response to calcium depletion

1986 ◽  
Vol 250 (4) ◽  
pp. G412-G419
Author(s):  
H. P. Schedl ◽  
D. L. Miller ◽  
R. L. Horst ◽  
H. D. Wilson ◽  
K. Natarajan ◽  
...  
Keyword(s):  
Vitamin D ◽  
Small Intestine ◽  
Calcium Transport ◽  
Spontaneously Hypertensive Rat ◽  
Calcium Depletion ◽  
Spontaneously Hypertensive ◽  
Distal Small Intestine ◽  
Wistar Kyoto

We previously found intestinal Ca2+ transport to be lower in the spontaneously hypertensive (SH) as compared with the Wistar-Kyoto control (WKY) rat. These animals were fed a relatively high (1%) Ca2+ diet, and the concentration of 1 alpha,25-dihydroxycholecalciferol [1 alpha,25(OH)2D3] in serum was the same in both groups. In the present experiment we tested the possibility that the lower Ca2+ transport in the SH rat was the result of unresponsiveness to 1 alpha,25(OH)2D3. We fed diets high and low in Ca2+ and measured serum 1 alpha,25(OH)2D3 and Ca2+ transport. Serum 1 alpha,25(OH)2D3 increased in response to Ca2+ depletion at both 5 and 12 wk in both the WKY and SH rat. With high-Ca2+ diet, Ca2+ transport was lower in SH than in WKY when studied 1) in vitro in duodenum at 5 wk of age, and 2) in vivo in proximal and distal small intestine at 12 wk of age. Ca2+ transport increased in SH in response to Ca2+ depletion, but not in WKY, except in distal small intestine in vivo at 12 wk. In summary, although Ca2+ transport is lower in the SH as compared with the WKY rat when vitamin D activity is basal through feeding a high-Ca2+ diet, Ca2+ transport increases in the SH rat in response to the increase in 1 alpha,25(OH)2D3 produced by feeding a low-Ca2+ diet. We conclude that 1) the vitamin D-regulated component of mediated Ca2+ transport is intact in the SH rat and is unrelated to hypertension, and 2) mediated Ca2+ transport under basal conditions, i.e., nonvitamin D-regulated, differs in the SH and WKY rats and may be related to hypertension.

Direct stimulating action of blood serum and of vitamin D3 and its hydroxy-analogs on calcium transport in the chicken small intestine in vitro

1980 ◽  
Vol 90 (6) ◽  
pp. 1676-1679 ◽  
Author(s):  
V. K. Bauman ◽  
R. E. Andrushaite ◽  
N. I. Berzin' ◽  
M. Yu. Valinietse ◽  
A. R. Val'dman
Keyword(s):  
Small Intestine ◽  
Blood Serum ◽  
Vitamin D3 ◽  
Calcium Transport

scholarly journals ELECTRON PROBE ANALYSIS OF CATIONIC SPECIES IN PYROANTIMONATE PRECIPITATES IN EPON-EMBEDDED TISSUE

1969 ◽  
Vol 17 (2) ◽  
pp. 102-106 ◽  
Author(s):  
BERNARD P. LANE ◽  
EUGENE MARTIN
Keyword(s):  
Electron Microscopy ◽  
Electron Probe ◽  
Osmium Tetroxide ◽  
Vas Deferens ◽  
Apical Plasma Membrane ◽  
Mouse Vas Deferens ◽  
Electron Probe Analysis ◽  
Osmium Tetroxide Solution ◽  
Potassium Pyroantimonate

Electron microscopy of Epon-embedded mouse vas deferens eipthelium treated with buffered potassium pyroantimonate-osmium tetroxide solution revealed precipitates in the lamina propria and along the apical plasma membrane. Electron microprobe elemental analysis of adjacent sections demonstrated that the deposits contained sodium and antimony. Other cations noted to precipitate pyroantimonate in vitro were not present in large amounts compared to controls, and were randomly distributed.

Transfer of Ca45 across intestinal wall in vitro in relation to action of vitamin D and cortisol

1960 ◽  
Vol 199 (2) ◽  
pp. 265-271 ◽  
Author(s):  
Harold E. Harrison ◽  
Helen C. Harrison
Keyword(s):  
Vitamin D ◽  
Small Intestine ◽  
Active Transport ◽  
Oxidative Metabolism ◽  
Calcium Transport ◽  
Proximal Part ◽  
Intestinal Wall ◽  
The Other ◽  
Cell Surfaces

The transfer of calcium across the intestinal wall of rats was measured in vitro by the device of everted intestinal loops with Ca45 as an indicator. The conditions were developed so that the rate of diffusion of calcium across the intestinal wall as well as active transport against a concentration gradient could be determined. Vitamin D treatment increases the rate of diffusion of calcium across the intestinal wall. This action of vitamin D is exerted along the entire length of the small intestine and is not affected by inhibition of oxidative metabolism. The active transport of calcium on the other hand is localized to the proximal part of the intestine and is dependent on the energy of oxidative metabolism. Cortisol treatment antagonizes the vitamin D effect on the diffusion of calcium and also reduces the active transport of calcium. It is suggested that vitamin D and cortisol influence calcium transport by action on the permeability of cell surfaces to calcium.

Intestinal Goblet Cell Mucus: Isolation and Identification by Immunofluorescence of a Goblet Cell Glycoprotein

1973 ◽  
Vol 12 (2) ◽  
pp. 585-601
Author(s):  
J. FORSTNER ◽  
N. TAICHMAN ◽  
V. KALNINS ◽  
G. FORSTNER
Keyword(s):  
Molecular Weight ◽  
Small Intestine ◽  
Goblet Cell ◽  
High Speed ◽  
Rabbit Antiserum ◽  
The Body ◽  
Intestinal Lumen ◽  
Intestinal Cell ◽  
Isolation And Identification ◽  
Cell Mucus

A high-molecular-weight glycoprotein (HMG), representing the majority of the soluble glycoprotein hexosamine and hexose in the intestine, was isolated by Sepharose 4B chromatography from high-speed supernatants of rat small intestinal homogenate. Fluorescein-labelled globulin, from rabbit antiserum produced against HMG, specifically stained supra-nuclear mucus vesicles of goblet cells in small intestine and colon as well as gastric pit cells in the body of the stomach and mucus-producing cells in the sublingual salivary gland. A single precipitin line was found when HMG was tested against its antibody by agar immunodiffusion and immunoelectrophoresis. No cross-reactivity was observed between antibody and rat serum or extracts from microvillus membrane, human colon and pig intestine. Precipitin lines which fused with the HMG precipitin arc in apparent identity were observed with antigens in intestinal lumen washings, and in small-molecular-weight fractions from intestinal cell sap. When studied by cellulose acetate electrophoresis, cetyl trimethylammonium bromide precipitation and precursor labelling with [I-14C]glucosamine, HMG behaved as a single homogeneous glycoprotein free of detectable protein contamination. These results imply that HMG is a major component of goblet-cell mucus in the small intestine, and suggest that it is similar to mucin produced throughout the gastrointestinal tract. HMG is the first glycoprotein, isolated without the aid of proteolytic agents, which has been specifically identified as a product of the goblet cell.

Combined Scanning—Transmission and Electron Probe Analysis of the Mammalian Small Intestine

1971 ◽  
Vol 29 ◽  
pp. 64-65
Author(s):  
A. J. Tousimis
Keyword(s):  
Small Intestine ◽  
Nucleic Acids ◽  
Electron Probe ◽  
Ionic Species ◽  
Biological Tissues ◽  
Electron Probe Analysis ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Ultrathin Sections ◽  
Cellular Components

The fine structure of the epithelium lining of the small intestine has been extensively studied by transmission electron microscopy of ultrathin sections during the past two decades.Chemical identification of cellular components, visualized by this method, have been limited primarily to the physicochemical identification of isolated fractions. Biochemical reactions carried out on these components are utilized for the indirect localization of macromolecular species such as proteins, carbohydrates, lipids, nucleic acids, nucleoproteins and other. Similarly, ionic species-electrolytes, nucleic acids and other molecular species transported or utilized by and for cellular activity have been “localized” by indirect methods only.Early electron probe microanalyses of biological tissues have been applied in the localization and measurement of structural components of the cell, mineral or inclusion and biological calcification studies. Measurement of organic molecules in situ is possible only on tissue sections that have been specifically reacted with chemicals that can be elementally differentiated from other cellular structures.

Influence of vitamin D on calcium absorption in the chick

1962 ◽  
Vol 203 (3) ◽  
pp. 497-505 ◽  
Author(s):  
J. D. Sallis ◽  
E. S. Holdsworth
Keyword(s):  
Vitamin D ◽  
Small Intestine ◽  
Calcium Transport ◽  
Calcium Absorption ◽  
Metabolic Inhibitors ◽  
Hydroxyl Groups ◽  
Oxidation Reduction ◽  
Active Calcium

The site of absorption of Ca45 was studied in rachitic chicks and rachitic chicks given vitamin D3. Vitamin D3 markedly increases absorption from the small intestine and, in vivo, similar amounts of calcium are absorbed along the entire small intestine. With everted gut sacs, the distal third of the small intestine transported much more calcium than did the duodenal and middle sections. Thus, interpretations of in vitro results may not always depict the natural in vivo process. Vitamin D2 had little activity in the chick, but AT-10 series 2 and AT-10 series 3 were almost as active as vitamin D3 for calcium transport. These results suggest an "active carrier" may be formed by addition of hydrogen or hydroxyl groups to the opened ring B of vitamin D, giving a carrier capable of reversible oxidation-reduction or keto-enol tautomerism. Using metabolic inhibitors, active calcium transport in vitro relied on glycolysis for its energy supply. The transport was independent of the sodium pump.

Electron Probe Analysis of Muscle

1982 ◽  
Vol 40 ◽  
pp. 398-401
Author(s):  
A. V. Somlyo ◽  
H. Shuman ◽  
A. P. Somlyo
Keyword(s):  
Skeletal Muscle ◽  
Smooth Muscle ◽  
Sarcoplasmic Reticulum ◽  
Resting State ◽  
Binding Sites ◽  
Electron Probe ◽  
Frog Skeletal Muscle ◽  
Electron Probe Analysis ◽  
Probe Analysis

Electron probe analysis of frozen dried cryosections of frog skeletal muscle, rabbit vascular smooth muscle and of isolated, hyperpermeab1 e rabbit cardiac myocytes has been used to determine the composition of the cytoplasm and organelles in the resting state as well as during contraction. The concentration of elements within the organelles reflects the permeabilities of the organelle membranes to the cytoplasmic ions as well as binding sites. The measurements of [Ca] in the sarcoplasmic reticulum (SR) and mitochondria at rest and during contraction, have direct bearing on their role as release and/or storage sites for Ca in situ.

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