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Biomedical subjects

V A Ioffe

Publications and source records attributed to V A Ioffe.

12 recordsLinked to original sources
PubMed1983

[Microfluorimeter for chromosome study].

A microfluorimeter is described for estimating amounts of chemical components in individual cells or in chromosomes, and for registering these components' distribution along the chromosomes. To solve the former problem, photoelectrical photometry of the object's fluorescence intensity is employed. To solve the latter problem, the photographic technique is used--making photos of metaphase plates in automatic or semiautomatic regime of exposure, with the following measuring of the intensity of the chromosome image on the negative performed on the same apparatus. The results of estimation of DNA content in individual chromosomes of Muntiacus muntjak are presented.

Animals↗
PubMed1982

[Spectral luminescence studies of cells stained with acrichine derivatives].

Excitation and fluorescence spectra are given of quinacrine derivative solutions, of buccal epithelium cell nuclei, of peripheral blood cells, and of isolated chromosomes treated with propyl-quinacrine mustard. It is confirmed that the differential cell treatment with quinacrine derivates may be observed in aqueous solutions only. Data obtained allow us to give some recommendations for employment of optimal filters and dichroic beam-splitters in the fluorescence microscopy of chromosomes treated with quinacrine derivatives.

Blood Cells↗
PubMed1979

[Relationship of the DNA content in the nuclei of Amoeba proteus to the food regimen].

The relative DNA content of isolated Amoeba proteus nuclei has been measured by cytofluorometry. With the amoeba strain studied, the generation time is roughly equal to 48 hours at 25 degrees C, and with the presence of food in the medium. After the synchronous divisions, amoebae were maintained in the medium either with or without food organisms (Tetrahymena pyriformis). DNA contents in the nuclei of both the amoebae groups were measured within 4 and 48 hours after division. Before 16 hours, the nuclear DNA contents did not differ in either group. Starting from 20 hours, the DNA amount in fed amoebae exceeded that in starved animals. On the whole, the differences in DNA quantity increased by a 48th hour after division, when the nuclei of the former contained 145% DNA of the latter. The results obtained suggest that the DNA synthesis in amoeba nuclei may proceed during the whole interphase, and that during the second half of interphase the content of DNA may depend on the feeding intensity in amoebae. After refeeding the starved animals, DNA contents in their nuclei increased to reach the same level as in the constantly fed amoebae seen in the end of interphase.

Amoeba↗
PubMedDate not supplied

[DNA content in Streptoverticillium mucoheptinicum spores in the period of their germination].

Changes in the DNA content were studied in the spores of Streptoverticillium mycoheptinicum. The content of DNA increased in the spores when they were incubated in a liquid nutrient medium at 28 degrees C for 5 hours. Changes in the DNA content during germination of spores corresponded to individual stages: at the stage of activation, the replication of DNA only commenced; at the stage of initiation, the content of DNA doubled in the majority of spores in the population. The rate of DNA synthesis varied among different spores of the actinomycete.

Culture Media↗