Xanthacin. A bacteriocin of Myxococcus xanthus f b

1974 ◽  
Vol 20 (2) ◽  
pp. 131-135 ◽  
Author(s):  
Howard D. McCurdy Jr. ◽  
Thomas H. MacRae
Keyword(s):  
Molecular Sieve ◽  
Density Gradient Centrifugation ◽  
High Titer ◽  
Gradient Centrifugation ◽  
Myxococcus Xanthus ◽  
Sodium Dodecyl ◽  
Uranyl Acetate ◽  
Partial Purification ◽  
Differential Centrifugation ◽  
Varied Size

An extremely stable, particulate, bacteriocin, namely xanthacin, has been found in Myxococcus xanthus f b after mitomycin C induction. Xanthacin is resistant to trypsin, protease type VI, RNase, DNase, sodium dodecyl sulfate (SDS), acetone, ether, ultraviolet irradiation, and autoclaving. A high-titer preparation was obtained after partial purification by pervaporative concentration, differential centrifugation, molecular sieve chromatography, and density gradient centrifugation. Electron microscopy of platinum-shadowed and uranyl acetate stained preparations revealed the presence of circular bodies of varied size which resembled membrane fragments.

Uranyl Acetate and Rotary Shadowing to Increase the Contrast of Small Aggregated Virus Particles

1969 ◽  
Vol 27 ◽  
pp. 424-425
Author(s):  
Lee F. Ellis ◽  
Richard M. Van Frank ◽  
Walter J. Kleinschmidt
Keyword(s):  
Electron Microscopy ◽  
Tissue Culture ◽  
Density Gradient ◽  
Density Gradient Centrifugation ◽  
Gradient Centrifugation ◽  
Uranyl Acetate ◽  
Interferon Inducer ◽  
Virus Particles ◽  
Staining Methods ◽  
Rotary Shadowing

The extract from Penicillum stoliniferum, known as statolon, has been purified by density gradient centrifugation. These centrifuge fractions contained virus particles that are an interferon inducer in mice or in tissue culture. Highly purified preparations of these particles are difficult to enumerate by electron microscopy because of aggregation. Therefore a study of staining methods was undertaken.

scholarly journals Isolation of the intercellular glycoproteins of desmosomes.

1981 ◽  
Vol 90 (1) ◽  
pp. 243-248 ◽  
Author(s):  
G Gorbsky ◽  
M S Steinberg
Keyword(s):  
Plasma Membranes ◽  
Gradient Centrifugation ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Insoluble Residue ◽  
Differential Centrifugation ◽  
Electron Microscopic ◽  
Nonionic Detergent ◽  
Cell Layers ◽  
Membrane Attachment

To characterize the desmosome components that mediate intercellular adhesion and cytoskeletal-plasma membrane attachment, we prepared whole desmosomes and isolated desmosomal intercellular regions (desmosomal "cores") from the living cell layers of bovine muzzle epidermis. The tissue was disrupted in a nonionic detergent at low pH, sonicated, and the insoluble residue fractionated by differential centrifugation and metrizamide gradient centrifugation. Transmission electron microscopic analyses reveal that a fraction obtained after differential centrifugation is greatly enriched in whole desmosomes that possess intracellular plaques. Metrizamide gradient centrifugation removes most of the plaque material, leaving the intercellular components and the adjoining plasma membranes. Sodium dodecyl sulfate polyacrylamide gel electrophoresis coupled with methods that reveal carbohydrate-containing moieties on gels demonstrate that certain proteins present in whole desmosomes are glycosylated. These glycoproteins are specifically and greatly enriched in the desmosome cores of which they are the principal protein constituents, and thus may function as the intercellular adhesive of the desmosome.

scholarly journals LYSOSOMES IN RAT THORACIC DUCT LYMPHOCYTES FRACTIONATED BY ZONAL CENTRIFUGATION

1973 ◽  
Vol 59 (1) ◽  
pp. 177-184 ◽  
Author(s):  
William E. Bowers
Keyword(s):  
Thoracic Duct ◽  
Light Microscope ◽  
Cathepsin D ◽  
Density Gradient Centrifugation ◽  
Gradient Centrifugation ◽  
Differential Centrifugation ◽  
Acid Hydrolases ◽  
Fractionation Method

A method of zonal centrifugation was developed which separates rat thoracic duct lymphocytes (TDL) mainly according to size. The validity of the fractionation method was supported by light microscope observations, Coulter Counter sizing, and in vivo and in vitro labeling of lymphocytes. The distributions of lysosomal acid hydrolases in TDL fractionated by zonal centrifugation are similar to the distribution obtained for the cells. This result indicates that the large lymphocyte is not the sole bearer of either lysosomes or the large amount of soluble cathepsin D found in homogenates of TDL. Both reside mainly in small lymphocytes. This point was clearly established by fractionating homogenates of purified small lymphocytes by means of differential centrifugation and isopycnic density gradient centrifugation.

scholarly journals Incorporation of [14C]glucosamine and [14C]leucine into mouse kidney β-glucuronidase induced by gonadotrophin

1970 ◽  
Vol 117 (1) ◽  
pp. 161-167 ◽  
Author(s):  
Keitaro Kato ◽  
Hiroyuki Ide ◽  
Tsuranobu Shirahama ◽  
William H. Fishman
Keyword(s):  
Endoplasmic Reticulum ◽  
Microsomal Fraction ◽  
Density Gradient Centrifugation ◽  
Gradient Centrifugation ◽  
Sucrose Density Gradient ◽  
Mouse Kidney ◽  
Differential Centrifugation ◽  
Freezing And Thawing ◽  
Sucrose Density Gradient Centrifugation ◽  
Glucuronidase Activity

Male BALB/C mice were injected intraperitoneally with 2.5 i.u. of gonadotrophin. After the injection, increase of β-glucuronidase activity was first observed in the microsomal fraction. By 36h 45–50% of the total homogenate activity was found in the microsomal fraction compared with 20–25% in the control microsomal fraction. From 36 to 80h not only microsomal β-glucuronidase but also lysosomal β-glucuronidase increased progressively. After 69h stimulation with 2.5 i.u. of gonadotrophin, d-[1-14C]glucosamine or l-[U-14C]leucine was injected intraperitoneally. After a further 3h the kidneys were homogenized and five particulate fractions were prepared by differential centrifugation. The β-glucuronidase in the microsomal and lysosomal fractions was released respectively by ultrasonication and by freezing and thawing treatment. The enzyme was purified by organic-solvent precipitation and by sucrose-density-gradient centrifugation. The results demonstrated the incorporation of these two labels into the mouse renal β-glucuronidase. The microsomal β-glucuronidase was much more radioactive than the lysosomal enzyme and approx. 80% of the newly synthesized enzyme appeared in microsomes and approx. 20% of that was found in lysosomes at this period. These results suggest that the mouse renal β-glucuronidase is a glycoprotein and that the newly synthesized enzyme is transported from endoplasmic reticulum to lysosomes.

Subcellular Localization of Enterokinase in Human Duodenal Mucosa

1977 ◽  
Vol 53 (6) ◽  
pp. 551-562 ◽  
Author(s):  
R. W. Lobley ◽  
Ruth Franks ◽  
R. Holmes
Keyword(s):  
Brush Border ◽  
Soluble Fraction ◽  
Density Gradient Centrifugation ◽  
Sucrose Solution ◽  
Gradient Centrifugation ◽  
Total Activity ◽  
Duodenal Mucosa ◽  
Differential Centrifugation ◽  
Marker Enzymes ◽  
Suitable Marker

1. Specimens of human duodenal mucosa were obtained at duodenotomy. Superficial mucosal scrapings were homogenized in isotonic sucrose solution and fractionated by differential centrifugation. The distribution of organelles among the subcellular fractions was monitored by assay of suitable marker enzymes. 2. Enterokinase was recovered predominantly in the nuclear + brush-border fraction and 80% of the total activity was found to be particulate; approximately 20% of the enzyme was present in the soluble fraction, compared with 1% of the brush-border markers sucrase and alkaline phosphatase. 3. The brush-border-containing fraction was subfractionated by treatment with hypertonic Tris followed by differential and density gradient centrifugation. Enterokinase was distributed among the subfractions in parallel with brush-border markers and was concentrated in a subfraction which was highly enriched in microvillous membranes. 4. It was concluded that enterokinase is localized primarily to the microvillous membrane of the epithelial cell brush border in man, but that in addition a proportion of the enzyme may be present in a soluble or easily released form in the duodenal mucosa.

scholarly journals Intramitochondrial localization of δ-aminolaevulate synthetase and ferrochelatase in rat liver

1969 ◽  
Vol 114 (3) ◽  
pp. 455-461 ◽  
Author(s):  
Roxane McKay ◽  
R. Druyan ◽  
G. S. Getz ◽  
M. Rabinowitz
Keyword(s):  
Glutamate Dehydrogenase ◽  
Density Gradient ◽  
Malate Dehydrogenase ◽  
Rat Liver ◽  
Mitochondrial Biogenesis ◽  
Mitochondrial Membrane ◽  
Density Gradient Centrifugation ◽  
Gradient Centrifugation ◽  
Differential Centrifugation ◽  
Inner Mitochondrial Membrane

Intramitochondrial loci for δ-aminolaevulate synthetase and ferrochelatase, the initial and final enzymes in haem synthesis, have been found in rat liver. Two different methods of fractionation were applied to mitochondria: (a) sonication and density-gradient centrifugation; (b) treatment with digitonin and differential centrifugation. Similar results were obtained with each technique. δ-Aminolaevulate synthetase is distributed similarly to two known matrix enzymes, malate dehydrogenase and glutamate dehydrogenase. Ferrochelatase is firmly bound to the the inner mitochondrial membrane. These results are considered in terms of the regulation of haem synthesis and in relation to mitochondrial biogenesis.

PSEUDOMONAS AERUGINOSA BACTERIOPHAGE SD1

1966 ◽  
Vol 12 (5) ◽  
pp. 885-893 ◽  
Author(s):  
P. D. Shargool ◽  
E. E. Townsend
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Thermal Denaturation ◽  
Density Gradient Centrifugation ◽  
Gradient Centrifugation ◽  
Cesium Chloride ◽  
Defined Medium ◽  
Differential Centrifugation ◽  
Ordered Structure ◽  
Base Analysis ◽  
Denaturation Profile

A DNA-containing bacteriophage, designated SD1, was isolated from sewage, using strain B71 of Pseudomonas aeruginosa as host. Lysates titering 1 to 2 × 1011plaque-forming units/ml are produced by infecting cultures growing in a defined medium. Highly purified phage preparations were obtained by a procedure involving concentration with ammonium sulfate at pH 8.2, differential centrifugation, and density gradient centrifugation in cesium chloride solution.Electron microscopy revealed a structure possessing a head of regular hexagonal outline, 50 mμ in diameter, and a tail, 6.2 × 188 mμ. The phage contained approximately 2.8 × 10−17 g nitrogen, 8 × 10−18 g of phosphorus, and 1.1 × 10−16 g DNA per plaque-forming unit. Base analysis of SD1 DNA disclosed the presence of equimolar amounts of adenine and thymine and of guanine and cytosine; the latter two comprise 53% of the bases. The thermal denaturation profile of the isolated DNA indicates that SD1 DNA is a highly ordered structure: the guanine and cytosine content as estimated from the temperature of half maximal ultraviolet absorption agrees with that found by chemical analysis of the DNA.

Vacuolar Membranes: Isolation from Yeast Cells

1973 ◽  
Vol 28 (7-8) ◽  
pp. 417-424 ◽  
Author(s):  
W. van der Wilden ◽  
Ph. Matile ◽  
M. Schellenberg ◽  
J. Meyer ◽  
A. Wiemken
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Density Gradient Centrifugation ◽  
Gradient Centrifugation ◽  
Sedimentation Velocity ◽  
Isolation Procedure ◽  
Vacuolar Membrane ◽  
Yeast Cells ◽  
Differential Centrifugation ◽  
Whole Cells ◽  
Vacuolar Membranes

α-Mannosidase was found associated with the vacuolar membranes of yeast. The vacuoles were isolated by flotation from osmotically disrupted spheroplasts of Saccharomyces cerevisiae. The enzyme was used as marker for isolating vacuolar membrane fragments directly from whole cells which were mechanically disintegrated. Over 90% of the total α-mannosidase was recovered in the particulate fraction. The enzyme was present in all of the fractions obtained upon differential centrifugation. Density gradient centrifugation in Urografin (5 - 20% w/v) of preparations obtained by differential centrifugation between 20 000 and 50 000 × g did not result in density equilibrium of the membrane. An isolation procedure involving a sedimentation velocity cut in Urografin gradients has, therefore, been worked out.

scholarly journals The locations of cathepsin activity and β-glucuronidase in the Guerin T8 tumour

1970 ◽  
Vol 118 (3) ◽  
pp. 543-549 ◽  
Author(s):  
A. R. Poole
Keyword(s):  
Endoplasmic Reticulum ◽  
Density Gradient ◽  
Density Gradient Centrifugation ◽  
Gradient Centrifugation ◽  
Differential Centrifugation ◽  
Unit Membrane ◽  
Electron Microscopic ◽  
Cathepsin Activity ◽  
Density Gradient Sedimentation

Tumour homogenate fractions, isolated by differential centrifugation, were subfractionated by density-gradient centrifugation. Biochemical and electron microscopic analyses revealed that β-glucuronidase and cathepsin activity were associated with a class (possibly two) of lysosomal particles of density greater than those of mitochondria and the endoplasmic reticulum. Lysosomes sedimented by low g forces were vacuolar, electron-dense, delineated by a unit membrane and about 0.2μm in diameter. β-Glucuronidase was also apparently associated with ribosomes whereas cathepsin was bound in part to the endoplasmic reticulum. Catalase and glucose 6-phosphatase possessed slightly different density-gradient sedimentation profiles.

scholarly journals Inactivation of Vaccinia Virus by gamma radiation

1966 ◽  
Vol 21 (1) ◽  
pp. 52-55 ◽  
Author(s):  
Rosa Jiménez ◽  
Adela Ohlbaum
Keyword(s):  
Gamma Radiation ◽  
Vaccinia Virus ◽  
Density Gradient Centrifugation ◽  
Survival Curve ◽  
Gradient Centrifugation ◽  
Sucrose Density Gradient ◽  
Target Volume ◽  
Differential Centrifugation ◽  
Sucrose Density Gradient Centrifugation ◽  
Negative Results

The influence of the purification on the inactivation of Vaccinia Virus (VV) by gamma radiation has been studied. Differential centrifugation and sucrose density gradient centrifugation have been used. Purification modifies the VV compound survival curve previously published 12.The possibility that multiple reactivation might be the reason of compound survival curve when crude virus preparations were irradiated has also been studied, but the experiments made give negative results.Even with the best method of purification applied, the target volume of about 10-17 cm3 for VV calculated from the irradiation experiments is very small compared to the volume of the virus obtained with the sedimentation methods.

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