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Biomedical subjects

M Reich

Publications and source records attributed to M Reich.

At least 109 records · Page 6Linked to original sources

[The course of zonular fiber. A further electronenmicroscopic study (author's transl)].

Zonular fibers could be shown between the basement membrane of the pigmented epithelium of pars plana and the elastic tissue of Bruch's membrane. A connection of zonular fibrils between the unpigmented epithelium and the basement membrane of pigmented epithelium of the pars plana could not be observed. It is possible to discuss two independent courses of zonular fibers.

Basement Membrane↗

Characterization and comparison of mycobacterial antigens by discontinuous pore gradient gel electrophoresis.

Concentrated culture filtrates and cell extracts were prepared from selected mycobacteria and analyzed by a multistage polyacrylamide electrophoretic procedure. Various staining procedures were used to detect protein, carbohydrate, nucleic acid, and lipid constituents. Visual examination of the more prominently stained components indicated differences and similarities in each species of Mycobacteria. The majority of the individual components were of small molecular weight; however, there appeared in all culture filtrates and extracts examined a slowly moving protein component of relatively large molecular size. Evidence based on immunodiffusion suggests that it is a common mycobacterial antigen.

Animals↗

Characterization and comparison of mycobacterial antigens by two-dimensional polyacrylamide gel electrophoresis.

Cell extracts and culture filtrates were prepared from several mycobacterial species and subjected to two-dimensional acrylamide gel electrophoresis. The cell preparations were first electrophoresed in a 7% homogeneous gel followed by a second electrophoresis, at right angles to the first separation, in a 2 to 30% linear gel gradient slab. Because the stained slab resembled a "fingerprint" or "peptide map," this procedure has been called "electroprotein mapping." More than 200 protein-staining spots were detected in several of the cell extracts, each map being characteristic of the species examined. The single most characteristic portion of each map was the region between the 16 and 30% gel concentrations. This region consisted of several small-molecular-weight components (many of peptide proportions) which together appeared as the most anodic band in the 7% gel column (first separation). The number and location of these components in the linear gel slab (second separation) were specific for each species tested. By electrophoresis of molecular-weight markers (i.e., albumin, myoglobin, cytochrome c) with and across (transverse electrophoresis) the gel gradient, the relative molecular weights of the unknown cell extract components could be estimated. These results suggest that two-dimensional acrylamide gel electrophoresis is a useful tool for the characterization of mycobacterial cell constituents.

Antigens, Bacterial↗

Characterization and comparison of mycobacterial antigens by two-dimensional immunoelectrophoresis.

Two-dimensional immunoelectrophoresis (2D-IEP), in which a complex of antigens is subjected to electrophoresis first through an agarose matrix in one direction and secondly through an antiserum-agarose matrix at right angles to the first direction, was evaluated as a tool for analysis of mycobacterial antigens. Cell extracts from four species of mycobacteria, Mycobacterium tuberculosis (four strains), M. bovis strain BCG, M. scrofulaceum, and M. phlei, were assayed by 2D-IEP with four anti-mycobacterial antisera. Besides displaying the precipitin curves in a more easily interpreted format than did conventional immunoelectrophoresis (IEP), 2D-IEP offered greater sensitivity in terms of numbers of precipitin curves when like reactions were compared with IEP patterns. As many as 60 immunoprecipitates were observed on 2D-IEP slides compared to 18 on comparable IEP plates. Technical reproducibility of patterns from run to run was excellent. Other parameters, such as the influence of using different batches of antigen on the pattern, are discussed. Each of the cell extract antigens gave a unique pattern of precipitin peaks which could be easily differentiated from the patterns given by the other mycobacterial cell extracts when reacted with any of the antisera in 2D-IEP. Since both the species and strains of mycobacteria could be easily and reproducibly differentiated solely on the basis of two-dimensional immunoelectrophoretic patterns obtained with any of the antisera employed in this study, it may be possible, by using IEP, to differentiate and identify all species and strains of mycobacteria with one standard, highly sensitive antiserum, rather than a battery of antisera.

Animals↗

Dissociation of cellular functions in Bacillus cereus by 5-fluorouracil.

Reich, Melvin (The George Washington University School of Medicine, Washington, D.C.), and H. George Mandel. Dissociation of cellular functions in Bacillus cereus by 5-fluorouracil. J. Bacteriol. 91:517-523. 1966.-5-Fluorouracil (FU) produced a marked inhibition of growth and deoxyribonucleic acid (DNA) synthesis in Bacillus cereus 569H. Protein and ribonucleic acid (RNA) synthesis were not specifically inhibited, and proceeded at the rate of turbidometric increase of the cells. Cell-wall synthesis, respiration, and penicillinase production continued in the presence of FU at essentially the control rate. The addition of equimolar concentrations of uracil and FU prevented growth inhibition but did not restore DNA synthesis. The addition of thymidine with FU did not relieve growth inhibition but did restore the DNA content to normal. Thymidine supplementation also increased the quantity of FU, but not uracil, incorporated into RNA and the acid-soluble fraction. The data indicate that inhibition of growth can be dissociated from inhibition of DNA synthesis and that more DNA is present in normal cells than is needed for growth and reproduction.

Adenine↗