scholarly journals Isolation and partial characterization of rat duodenal-gland (Brunner's-gland) mucus glycoprotein

1982 ◽  
Vol 203 (3) ◽  
pp. 779-785 ◽  
Author(s):  
H L Smits ◽  
P J M van Kerkhof ◽  
M F Kramer
Keyword(s):  
Small Intestine ◽  
Chemical Composition ◽  
Protein Content ◽  
Density Gradient Centrifugation ◽  
Gradient Centrifugation ◽  
Mucous Cells ◽  
Present Evidence ◽  
Mucus Glycoprotein ◽  
Duodenal Glands

A mucus glycoprotein was isolated from the duodenal glands of the rat and purified by repeated density-gradient centrifugation. The characterized glycoprotein is unique to the mucous cells of the duodenal glands and is not present in parts of the small intestine devoid of these glands. The chemical composition of the purified glycoprotein is characteristic for glycoproteins of the mucin-type. Its protein content is relatively high and amount to 35% by weight. No neuraminic acid and little sulphate (2%) is present. Evidence is presented that the native glycoprotein is built up from subunits held together via disulphide bridges in a non-glycosylated region of the protein core.

Dna Synthesis in Purified Populations of Avian Erythroid Cells

1972 ◽  
Vol 10 (1) ◽  
pp. 27-46
Author(s):  
A. F. WILLIAMS
Keyword(s):  
Biochemical Characterization ◽  
Bone Marrow Cells ◽  
Density Gradient Centrifugation ◽  
Gradient Centrifugation ◽  
Experimental System ◽  
Equilibrium Density ◽  
Polychromatic Erythrocytes ◽  
Type Size ◽  
Haemoglobin Content

By the use of equilibrium density-gradient centrifugation erythroblasts and early polychromatic erythrocytes have been isolated from avian anaemic bone marrow. Cells from both the unfractionated and purified preparations have been characterized in terms of their histological type, size, haemoglobin content and ability to synthesize DNA. Erythroblasts were the only cells to synthesize DNA and it appeared that their progeny, the polychromatic erythrocyte, failed to enter a new S phase. The experimental system described allows biochemical characterization of earlier stages of avian erythropoiesis than has previously been possible.

Influence de la cytochalasine A sur la composition de fractions subcellulaires d'hyphes en croissance du Mucor mucedo L. I. Composition du plasmalemme

1988 ◽  
Vol 34 (11) ◽  
pp. 1256-1265 ◽  
Author(s):  
Abdou Ahmed Abd El Razak El Mougith ◽  
Jean-Louis Fonvieille ◽  
Robert Dargent ◽  
Jacques Rami ◽  
Jane-Marie Touzé-Soulet
Keyword(s):  
Protein Content ◽  
Density Gradient ◽  
Density Gradient Centrifugation ◽  
Gradient Centrifugation ◽  
Sucrose Density Gradient ◽  
Point Of View ◽  
Continuous Density ◽  
Mucor Mucedo ◽  
Phospholipid Ratio ◽  
Enzymatic Markers

The plasma membrane of young hyphae of Mucor mucedo L. growing in presence or absence of cytochalasine A was isolated by continuous density gradient centrifugation using Percoll at 10% or on discontinuous sucrose density gradient. Isolated membranes were characterized by enzymatic markers and cytochemical reactions, using electron microscopy. Lipid composition and protein content were determined. From the enzymatic point of view, the cytochalasine A induced a decrease (60%) in ATPase activity and with regard to the chemical composition of the membrane, a decrease in sterol content and in the sterol – phospholipid ratio as well as a decrease in protein content and an increase in the proportion of cysteine relative to other amino acids.

scholarly journals Active Sugar Transport by the Small Intestine

1968 ◽  
Vol 52 (3) ◽  
pp. 482-494 ◽  
Author(s):  
Robert G. Faust ◽  
Mary G. Leadbetter ◽  
Regina K. Plenge ◽  
Alston J. McCaslin
Keyword(s):  
Small Intestine ◽  
Brush Border ◽  
Brush Border Membrane ◽  
Density Gradient Centrifugation ◽  
Gradient Centrifugation ◽  
Sugar Transport ◽  
Initial Step ◽  
Inhibitory Effect ◽  
Glucose Binding ◽  
Brush Borders

Tris-disrupted and intact brush border membrane preparations from mucosa of hamster jejunum were capable of preferentially binding actively transported D-glucose in a similar manner. Density gradient centrifugation of the Tris-disrupted brush borders indicated that D-glucose was bound to a fraction containing the cores or inner material of the microvilli. The properties of this binding were examined with the Tris-disrupted brush border preparation. Actively transported sugars competitively inhibited preferential D-glucose binding, whereas no effect was observed with nonactively transported sugars. Neither actively nor nonactively transported amino acids affected D-glucose binding. D-Glucosamine, which is not actively transported, was inhibitory to preferential D-glucose binding as well as to the active transport of D-glucose by everted sacs of hamster jejunum. No inhibitory effect was observed with the same concentration of D-galactosamine. Preferential D-glucose binding was also inhibited by sulfhydryl-reacting compounds, Ca2+, and Li+ ions. On the other hand, Mg2+ was shown to be stimulatory and Na+, NH4+, and K+ had no effect on this phenomenon. The results of these experiments suggest that preferential D-glucose binding to brush borders is related to the initial step in active sugar transport by the small intestine.

scholarly journals OCCURRENCE, ISOLATION, AND CHARACTERIZATION OF POLYRIBOSOMES IN YEAST

1967 ◽  
Vol 34 (2) ◽  
pp. 505-512 ◽  
Author(s):  
Leon Marcus ◽  
H. Ris ◽  
H. O. Halvorson ◽  
R. K. Bretthauer ◽  
R. M. Bock
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Density Gradient Centrifugation ◽  
Gradient Centrifugation ◽  
Nearest Neighbors ◽  
Amino Acid Incorporation ◽  
Size Classes ◽  
Isolation And Characterization ◽  
Acid Incorporation

This report details the procedural requirements for preparing cell-free extracts of yeast rich in polyribosomes. This enabled us to demonstrate the occurrence of polyribosomes in yeast, to show their role in protein synthesis, and to devise methods for their resolution and isolation. When certain precautions are met (the use of log phase cells, rapidly halting cell growth, gentle methods of disruption, sedimentation through exponential density gradients, etc.), individual polyribosome size classes ranging up to the heptosome can be fractionated and separated from their nearest neighbors. Larger size classes are resolved partially among themselves, free of smaller polyribosomes. This was confirmed by extensive electron micrographic studies of material from the various fractions obtained upon density gradient centrifugation of yeast extracts. Modifications of the gradients and procedure should allow fractionation and isolation of the larger polyribosomes, including those containing polycistronic messages. Yeast polyribosomes are disaggregated to single ribosomes by longer term grinding, cell disruption by the French pressure cell, the Hughes press, or by incubation with dilute RNAse. Yeast polyribosomes are active in the incorporation of amino acids into polypeptide; the single ribosomes exhibit only slight activity. The latter activity is probably due to the presence of a small fraction of monosomes still containing mRNA. Poly-U stimulates amino acid incorporation only in the single ribosomes.

Studies on the histamine-sensitizing factor of Bordetella pertussis by density gradient centrifugation

1968 ◽  
Vol 14 (5) ◽  
pp. 525-528 ◽  
Author(s):  
B. W. Griffiths ◽  
M. A. Mason
Keyword(s):  
Chemical Composition ◽  
Density Gradient ◽  
Density Gradient Centrifugation ◽  
Biological Activities ◽  
Gradient Centrifugation ◽  
Molecular Size ◽  
Protein Profiles ◽  
Foreign Proteins ◽  
Relationship Of ◽  
The Relationship

The density gradient centrifugation of the histamine-sensitizing factor (HSF) of B. pertussis extracts in admixture with purified foreign proteins has revealed a property of the HSF not previously recognized. The HSF sedimentation was markedly accelerated in the presence of human serum macroglobulin and hog thyroglobulin. The absence of gross detectable changes in the protein profiles after the displacement of the HSF by sedimentation suggests the need for studies on the chemical composition of the HSF.The affinity of the HSF towards the foreign proteins, particularly those of large molecular size, has suggested a useful model by which the relationship of the HSF to other biological activities of B. pertussis may be studied.

Sign in / Sign up

Export Citation Format

Share Document