scholarly journals Absorption and metabolism of fructose by rat jejunum

1984 ◽  
Vol 222 (1) ◽  
pp. 57-64 ◽  
Author(s):  
P A H Holloway ◽  
D S Parsons
Keyword(s):  
Marked Decrease ◽  
Rat Jejunum ◽  
Vascular Bed ◽  
Equivalent Concentration ◽  
The Difference ◽  
Free Monosaccharide

The absorption and metabolism of fructose was investigated in the vascularly perfused jejunum of fructose-fed rats. With 10 mM-glutamate and 10 mM-fructose in the lumen, the viability of the tissue is maintained and fructose is absorbed and utilized at high rates. With 28 mM-fructose in the lumen, glucose appears in the vascular bed. With 10 mM- or 28 mM-fructose in the presence of 10 mM- or mM-glucose in the lumen, the fructose absorption is decreased. From 10 mM- or 28 mM-sucrose in the lumen, fructose uptake is also less than from the equivalent concentration of free fructose. The rate of appearance of fructose in the vascular bed is independent of the source of fructose from which it is derived. In the presence of glucose, either free or as sucrose, there is a marked decrease in the utilization of fructose, defined as the difference between that absorbed by the jejunum and that transported unchanged into the vascular bed. In all cases about half of the carbohydrate absorbed from the lumen is converted into lactate, most of which is secreted into the blood. The absorption of glucose and the rate of vascular appearance of glucose from glucose in the lumen are about 1.5 times greater than those of fructose from fructose in the lumen. It is concluded: firstly, that fructose uptake from the lumen of rat jejunum is determined by its concentration and by the demand for it as a fuel for the intestine, a demand that is severely decreased in the presence of glucose; secondly, that in the vascularly perfused jejunum there is no evident kinetic advantage for uptake of fructose or glucose from sucrose rather than from free monosaccharide in the lumen; thirdly, that some fructose can be converted into glucose.

Final Lowering in Kipare

Phonology ◽  
1996 ◽  
Vol 13 (2) ◽  
pp. 171-196 ◽  
Author(s):  
Rebecca Herman
Keyword(s):  
Experimental Study ◽  
Fundamental Frequency ◽  
Marked Decrease ◽  
Pitch Range ◽  
Downward Motion ◽  
Tone Languages ◽  
Testing Ground ◽  
Normal Sentence ◽  
The Difference

In many languages, fundamental frequency shows a marked decrease utterance-finally or phrase-finally. Ladefoged (1982) generalises that ‘in nearly all languages the completion of a grammatical unit such as a normal sentence is signaled by a falling pitch’. Bolinger (1978) also writes that ‘the most widely diffused intonational phenomenon seems to be the tendency to “go down at the end”’. These sorts of abrupt decreases which affect only the end of the utterance (known as FINAL LOWERING) are distinct from gradual decreases in fundamental frequency over the course of the entire utterance (known as DECLINATION). Bolinger (1978) notes the same distinction, characterising it as the difference between ‘a rapid downward motion at the very end, usually if not always associated with a terminal accent’ and ‘downward drift from a high beginning’. Final lowering as distinct from declination is documented in Japanese by Poser (1984) and by Pierrehumbert & Beckman (1988); in English by Liberman & Pierrehumbert (1984); in Dutch by Gussenhoven & Rietveld (1988); in Danish by Thorsen (1985); in Yoruba by Connell & Ladd (1990) and by Laniran (1992); and in Kikuyu by Clements & Ford (1981) (although not all authors use the exact terminology presented here).Analyses of final lowering range from attributing final lowering to changes in tonal categories (discussed below in §4) to attributing final lowering to compression of the pitch range in the last section of the sentence (discussed below in §5.1). Tone languages provide an interesting testing ground for analyses of final lowering. Careful experimental study, controlling for the position of a tone from the beginning and from the end of a sentence, is one way to begin to sort out the effects of various factors such as declination and final lowering on fundamental frequency.

scholarly journals Characterization of degradation process of sucrase-isomaltase in rat jejunum with monoclonal-antibody-based enzyme-linked immunosorbent assay

1988 ◽  
Vol 250 (1) ◽  
pp. 41-46 ◽  
Author(s):  
T Goda ◽  
A Quaroni ◽  
O Koldovský
Keyword(s):  
Monoclonal Antibody ◽  
Immunosorbent Assay ◽  
Active Site ◽  
Degradation Products ◽  
Degradation Process ◽  
Molar Ratio ◽  
Enzyme Linked Immunosorbent Assay ◽  
Pancreatic Ducts ◽  
Rat Jejunum ◽  
The Difference

As shown previously, during degradation of sucrase-isomaltase in rat jejunum, degradation of the sucrase active site occurs before that of isomaltase active site [Goda & Koldovský (1985) Biochem. J. 229, 751-758]. To characterize further the process of sucrase-isomaltase degradation in jejunum, we determined the amounts of immunoreactive sucrase-isomaltase in rat jejunum by using a monoclonal-antibody-based enzyme-linked immunosorbent assay. By employing two alternative monoclonal antibodies (one reacting with the sucrase subunit and the other reacting with the isomaltase subunit), the amount of antigen-containing sucrase subunit and the amount of antigen-containing isomaltase subunit were separately quantified. In both upper and lower jejunum of rats, the amount of antigen-containing isomaltase subunit was always higher than the amount of antigen-containing sucrase subunit. This difference was attributable mainly to a degradation product of sucrase-isomaltase, which was identified as isomaltase monomer. Occlusion of pancreatic ducts for 18 h eliminated the difference between the amount of antigen-containing sucrase subunit and the amount of antigen-containing isomaltase subunit in both upper and lower jejunum. In jejunum of control animals, the molar ratio of sucrase subunit to isomaltase subunit was estimated to be 0.32-0.52, indicating that quite a large proportion of sucrase-isomaltase (48-68%) is present as degradation products (e.g. isomaltase monomer). These results support the model of degradation process of sucrase-isomaltase in brush-border membranes of rat jejunum, whereby degradation of sucrase subunit by the action of pancreatic proteinase(s) precedes degradation of isomaltase subunit.

STRENGTH OF CALLUS IN FRACTURED HUMERUS OF RAT TREATED WITH ANTI-ANABOLIC AND ANABOLIC COMPOUNDS

1961 ◽  
Vol 36 (2) ◽  
pp. 310-318 ◽  
Author(s):  
K. B. Wiancko ◽  
K. Kowalewski
Keyword(s):  
Tensile Strength ◽  
Bone Formation ◽  
Marked Decrease ◽  
New Bone Formation ◽  
Anabolic Action ◽  
The Difference ◽  
Androgenic Steroids ◽  
Stimulation Of

ABSTRACT Anti-anabolic action of a lathyrus factor (BAPN) and of cortisone and anabolic action of androgenic steroids Dianabol (17α-methyl-17β-hydroxy-androsta-1,4-dien-3-one) and Ora-Testryl (9α-fluoro-11β-hydroxy-17α-methyltestosterone) on the healing of fractured humeri in rats was investigated. Tensile strength of healing callus measured at 1st, 2nd and 3rd week after fracture was determined to assess the difference in action between the compounds studied. Healing bones were also studied histologically. Significant decrease of tensile strength of callus was observed in BAPN treated rats at 2nd and 3rd week after fracture. Less marked decrease was noted in cortisone treated animals. Certain delay of new bone formation was notable, histologically, in callus of animals treated with anti-anabolic compounds. Both androgens studied were found to increase significantly tensile strength of callus at 1st and 2nd week after fracture. Increase of tensile strength was associated with marked stimulation of new bone formation and calcification of callus, observed on histological preparations.

The Origin of the Moon

1962 ◽  
Vol 14 ◽  
pp. 149-155 ◽  
Author(s):  
E. L. Ruskol
Keyword(s):  
Chemical Composition ◽  
Solar System ◽  
The Moon ◽  
The Earth ◽  
The Difference ◽  
Origin Of The Moon

The difference between average densities of the Moon and Earth was interpreted in the preceding report by Professor H. Urey as indicating a difference in their chemical composition. Therefore, Urey assumes the Moon's formation to have taken place far away from the Earth, under conditions differing substantially from the conditions of Earth's formation. In such a case, the Earth should have captured the Moon. As is admitted by Professor Urey himself, such a capture is a very improbable event. In addition, an assumption that the “lunar” dimensions were representative of protoplanetary bodies in the entire solar system encounters great difficulties.

Influence of Cell Wall Composition on the Fossilisation of Bacteria and the Implications for the Search for Early Life Forms

1997 ◽  
Vol 161 ◽  
pp. 491-504 ◽  
Author(s):  
Frances Westall
Keyword(s):  
Cell Wall ◽  
Life Forms ◽  
Cation Binding ◽  
Positive Bacterium ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Transmission Electron ◽  
Hydrothermal Sediments ◽  
Identification Of Bacteria ◽  
The Difference

AbstractThe oldest cell-like structures on Earth are preserved in silicified lagoonal, shallow sea or hydrothermal sediments, such as some Archean formations in Western Australia and South Africa. Previous studies concentrated on the search for organic fossils in Archean rocks. Observations of silicified bacteria (as silica minerals) are scarce for both the Precambrian and the Phanerozoic, but reports of mineral bacteria finds, in general, are increasing. The problems associated with the identification of authentic fossil bacteria and, if possible, closer identification of bacteria type can, in part, be overcome by experimental fossilisation studies. These have shown that not all bacteria fossilise in the same way and, indeed, some seem to be very resistent to fossilisation. This paper deals with a transmission electron microscope investigation of the silicification of four species of bacteria commonly found in the environment. The Gram positiveBacillus laterosporusand its spore produced a robust, durable crust upon silicification, whereas the Gram negativePseudomonas fluorescens, Ps. vesicularis, andPs. acidovoranspresented delicately preserved walls. The greater amount of peptidoglycan, containing abundant metal cation binding sites, in the cell wall of the Gram positive bacterium, probably accounts for the difference in the mode of fossilisation. The Gram positive bacteria are, therefore, probably most likely to be preserved in the terrestrial and extraterrestrial rock record.

Structuring, Motions and Shapes of Corona Emission Line Profiles

1994 ◽  
Vol 144 ◽  
pp. 421-426
Author(s):  
N. F. Tyagun
Keyword(s):  
Emission Line ◽  
Filling Factor ◽  
Direct Relationship ◽  
Coronal Plasma ◽  
Line Of Sight ◽  
Line Profiles ◽  
The Difference ◽  
Yellow Line ◽  
Red Line

AbstractThe interrelationship of half-widths and intensities for the red, green and yellow lines is considered. This is a direct relationship for the green and yellow line and an inverse one for the red line. The difference in the relationships of half-widths and intensities for different lines appears to be due to substantially dissimilar structuring and to a set of line-of-sight motions in ”hot“ and ”cold“ corona regions.When diagnosing the coronal plasma, one cannot neglect the filling factor - each line has such a factor of its own.

Difference Fourier Analysis of Glucose Embedded and Frozen Hydrated Purple Membrane

1982 ◽  
Vol 40 ◽  
pp. 74-75
Author(s):  
Jules S. Jaffe ◽  
Robert M. Glaeser
Keyword(s):  
Purple Membrane ◽  
Data Set ◽  
High Resolution Data ◽  
X Ray ◽  
X Ray Crystallography ◽  
Fourier Techniques ◽  
Versus Protein ◽  
The Difference ◽  
Difference Fourier ◽  
Ideal Method

Although difference Fourier techniques are standard in X-ray crystallography it has only been very recently that electron crystallographers have been able to take advantage of this method. We have combined a high resolution data set for frozen glucose embedded Purple Membrane (PM) with a data set collected from PM prepared in the frozen hydrated state in order to visualize any differences in structure due to the different methods of preparation. The increased contrast between protein-ice versus protein-glucose may prove to be an advantage of the frozen hydrated technique for visualizing those parts of bacteriorhodopsin that are embedded in glucose. In addition, surface groups of the protein may be disordered in glucose and ordered in the frozen state. The sensitivity of the difference Fourier technique to small changes in structure provides an ideal method for testing this hypothesis.

Destruction of Actin Filaments by Osmium Tetroxide

1977 ◽  
Vol 35 ◽  
pp. 466-467
Author(s):  
P. Maupin-Szamier ◽  
T. D. Pollard
Keyword(s):  
Actin Filaments ◽  
Time Course ◽  
Osmium Tetroxide ◽  
Rabbit Muscle ◽  
Muscle Actin ◽  
Sodium Phosphate Buffer ◽  
Transmission Electron ◽  
The Difference ◽  
Rates Of Decay ◽  
Short Time

We have studied the destruction of rabbit muscle actin filaments by osmium tetroxide (OSO4) to develop methods which will preserve the structure of actin filaments during preparation for transmission electron microscopy.Negatively stained F-actin, which appears as smooth, gently curved filaments in control samples (Fig. 1a), acquire an angular, distorted profile and break into progressively shorter pieces after exposure to OSO4 (Fig. 1b,c). We followed the time course of the reaction with viscometry since it is a simple, quantitative method to assess filament integrity. The difference in rates of decay in viscosity of polymerized actin solutions after the addition of four concentrations of OSO4 is illustrated in Fig. 2. Viscometry indicated that the rate of actin filament destruction is also dependent upon temperature, buffer type, buffer concentration, and pH, and requires the continued presence of OSO4. The conditions most favorable to filament preservation are fixation in a low concentration of OSO4 for a short time at 0°C in 100mM sodium phosphate buffer, pH 6.0.

Antiphase Boundaries in Ordered Ni3FE Crystals

1969 ◽  
Vol 27 ◽  
pp. 62-63
Author(s):  
Y. H. Liu
Keyword(s):  
Domain Size ◽  
Antiphase Domain ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hardening Mechanism ◽  
Superlattice Structure ◽  
Disordered Phase ◽  
Domain Boundaries ◽  
Atomic Scattering ◽  
The Difference

Ordered Ni3Fe crystals possess a LI2 type superlattice similar to the Cu3Au structure. The difference in slip behavior of the superlattice as compared with that of a disordered phase has been well established. Cottrell first postulated that the increase in resistance for slip in the superlattice structure is attributed to the presence of antiphase domain boundaries. Following Cottrell's domain hardening mechanism, numerous workers have proposed other refined models also involving the presence of domain boundaries. Using the anomalous X-ray diffraction technique, Davies and Stoloff have shown that the hardness of the Ni3Fe superlattice varies with the domain size. So far, no direct observation of antiphase domain boundaries in Ni3Fe has been reported. Because the atomic scattering factors of the elements in NijFe are so close, the superlattice reflections are not easily detected. Furthermore, the domain configurations in NioFe are thought to be independent of the crystallographic orientations.

The role of differential phase contrast in electron microscopy

1978 ◽  
Vol 36 (1) ◽  
pp. 176-177
Author(s):  
E.M. Waddell ◽  
J.N. Chapman ◽  
R.P. Ferrier
Keyword(s):  
Phase Contrast ◽  
Practical Method ◽  
Position Vector ◽  
Differential Phase ◽  
Pure Phase ◽  
Differential Phase Contrast ◽  
The Difference ◽  
Image Position ◽  
First Moment

Dekkers and de Lang (1977) have discussed a practical method of realising differential phase contrast in a STEM. The method involves taking the difference signal from two semi-circular detectors placed symmetrically about the optic axis and subtending the same angle (2α) at the specimen as that of the cone of illumination. Such a system, or an obvious generalisation of it, namely a quadrant detector, has the characteristic of responding to the gradient of the phase of the specimen transmittance. In this paper we shall compare the performance of this type of system with that of a first moment detector (Waddell et al.1977).For a first moment detector the response function R(k) is of the form R(k) = ck where c is a constant, k is a position vector in the detector plane and the vector nature of R(k)indicates that two signals are produced. This type of system would produce an image signal given bywhere the specimen transmittance is given by a (r) exp (iϕ (r), r is a position vector in object space, ro the position of the probe, ⊛ represents a convolution integral and it has been assumed that we have a coherent probe, with a complex disturbance of the form b(r-ro) exp (iζ (r-ro)). Thus the image signal for a pure phase object imaged in a STEM using a first moment detector is b2 ⊛ ▽ø. Note that this puts no restrictions on the magnitude of the variation of the phase function, but does assume an infinite detector.

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