Differential centrifugation of several plant extracts indicates that the majority of the hydroperoxide isomerase activity is present in the cytoplasm of the cell. However, lesser amounts of isomerase activity were found in the mitochondrial and microsomal fractions of sunflower seedlings. Sucrose density gradient centrifugation of extracts from sunflower, watermelon, and flax seedlings and from...

Velocity sedimentation and isopycnic density gradient centrifugation indicate that reticuloendotheliosis virus has a different mass and buoyant density than members of the avian tumor virus group. The group-specific antigen of the avian tumor virus group was not detected in concentrated and purified reticuloendotheliosis virus preparations.

A procedure for isolating spinach (Spinacia oleracea L.) leaf peroxisomes in 0.25 molar sucrose solution by Percoll density gradient centrifugation followed by removal of the Percoll by washing and centrifugation was established. The preparation contains more than 90% peroxisomes as intact organelles with no detectable chlorophyll or cytochrome oxidase contamination. The peroxisomes are stable ...

A method for isolating pure and unaltered nuclei from rat brain by means of differential centrifugation is described. The isolated nuclei are further separated into discrete fractions of neuronal, astrocytic, and glial nuclei, with a yield amounting to 20 to 25% of the DNA of the original homogenate. Both the morphology and size of the nuclei remained unchanged. Problems concerning the composit...

A nontypeable blood isolate of group B streptococci (GBS) from a patient with endocarditis is suggested to be the nonencapsulated phase of a GBS strain, type III. From the original high-density isolate, a low-density, encapsulated phase was selected by Percoll gradient centrifugation. This phenomenon should be considered before a GBS strain is classified as truly nontypeable.

Growth of a strain of Bacillus subtilis that requires uracil, thymine, adenine, and tryptophan in the presence of 5-fluorouracil (FU) results in the synthesis of ribonucleic acid (RNA) and ribosomes in which 55 to 65% of the RNA uracil has been replaced by the fluorine derivative. Examination of analogue-containing ribosomes by sucrose density gradient centrifugation and thermal denaturation st...

Four techniques for the detection and quantification of Dirofilaria immitis microfilariae in peripheral blood were compared, namely the conventional thick smear, thick films prepared by cytocentrifugation, filtration of blood through polycarbonate membranes, and density gradient centrifugation followed by membrane filtration. The efficiency of the methods and their sensitivity was assessed by d...

Chicken anaemia agent (CAA) was purified using differential centrifugation and successive cycles of equilibrium density gradient centrifugation using sucrose and CsCl. The purification method was dependent on the use of an antigen-detecting ELISA based on a CAA-specific monoclonal antibody. Virus particles banded at a density of 1.33 to 1.34 g/ml in CsCl and measured 23.5 +/- 0.8 nm in diameter...

To identify previously unknown peroxisomal proteins, we established an optimized method for isolating highly purified peroxisomes from etiolated soybean cotyledons using Percoll density gradient centrifugation followed by iodixanol density gradient centrifugation. Proteins in highly purified peroxisomes were separated by two-dimensional PAGE. We performed peptide mass fingerprinting of proteins...