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Biomedical subjects

E Kondo

Publications and source records attributed to E Kondo.

At least 181 records · Page 10Linked to original sources
PubMed1982

Electron microscopic demonstration of close contact between intracellular mycobacteria and the phagosomal membrane.

Ultrathin sections of granulomatous lung lesions of tuberculous mice were subjected to electron microscopy to observe the intraphagosomal behaviour of mycobacteria. The close contact between the external surface of the bacterial cell wall and the phagosomal membrane was a characteristic feature, This was also observed with ultrathin sections of a mycobacterial specimen harvested from the homogenate of such lungs. The significance of this event was interpreted in relation to the mechanism of mycobacterial infection.

Animals↗
PubMed1982

A novel type of lymphocyte-macrophage association revealed electron microscopically in tuberculous lung lesions of mice.

Electron microscopic survey of tuberculous lung lesions of mice revealed a novel type of lymphocyte-macrophage association. The finger-like projections with sharp or blunt tips of lymphocytes area formed as if pushing deeply the macrophage membrane to form pockets matching the shape of the projections. Intimate membrane contact occurs between these two cells, particularly at the leading edges. The biological significance of this morphological event remains to be a subject for future study.

Animals↗
PubMed1981

An electron microscopy study of intra-cellular mycobacteria in experimental mouse tuberculosis.

Ultra-thin sections for electron microscopy (EM) were prepared from granulomatous lungs which developed in mice in response to experimental infection by a highly virulent strain of M. bovis. A subsidiary study was made of the EM appearance of mycobacteria separated from the lung tissue homogenate by differential centrifugation and trypsin-digestion. Examination of many micrographs showed that the phagosomal membrane may, at least partly, be in close contact with the cell wall of ingested mycobacteria. Such areas of contact often produce an electron-dense granularity or a row of evenly-spaced minute granules, accompanying the damage to the inner structure of the bacterial cell. A variety of disintegrating bacterial figures were observed, characterized by inward detachment of the plasma membrane, shrinkage and digestion of the cytoplasm, and occasional rupture of the cell wall. Various forms of lamellated and osmophilic inclusion bodies were present in macrophages, but their relation to ingested mycobacteria was uncertain.

Animals↗
PubMed1981

Biosynthetic pathway of 2-deoxystreptamine.

Four 2-deoxystreptamine (DOS) related compounds including S-11-P, isolated as an intermediate of DOS biosynthesis, were supplemented to the culture of a DOS- mutant of Bacillus circulans. Among the tested aminocyclitol compounds, S-11-P alone was converted to DOS. Addition of other aminocyclitols neither produced antibiotic nor inhibited the incorporation of S-11-P and DOS into butirosins. By these facts, S-11-P was confirmed clearly to be an intermediate of DOS biosynthesis.

Bacillus↗
PubMed1980

Isolation of an intermediate of 2-deoxystreptamine biosynthesis from a mutant of Bacillus circulans.

Eight 2-deoxystreptamine-negative (DOS-) mutants were isolated from various strains of Bacillus circulans, normally producing butirosin, xylostasin and ribostamycin. These mutants were classified into two groups (converter and secretor) by the simple method of cosynthesis using agar plate culture. One of the cosynthetic pairs, strain S-11, an intermediate of DOS biosynthesis, S-11-P, was isolated. This compound was converted to butirosin (BTN) effectively by strain 236. The structure of S-11-P was considered to be (1 L or 1 D)-1,3,5/2,4-5-amino-cyclohexanetetrol, and the pathway of DOS biosynthesis is discussed here.

Anti-Bacterial Agents↗
PubMed1980

Structure elucidation of an intermediate of 2-deoxystreptamine biosynthesis.

The structure of a 2-deoxystreptamine (DOS) precursor named S-11-P, which was isolated by using a DOS negative mutant derived from a xylostasin-producing strain of Bacillus circulans B15M, has been elucidated as (1 L)-1,3,5/2,4,-5-aminocyclohexanetetrol by comparison with an authentic specimen, which was synthesized from kanamycin A.

Anti-Bacterial Agents↗
PubMed1980

Production of a new aminoglycoside antibiotic by a mutant of Bacillus circulans.

A new aminoglycoside antibiotic, S-11-A, was isolated from the fermentation broth of the 2-deoxystreptamine negative (DOS-) mutant of Bacillus circulans S-11. The structure of S-11-A was elucidated as 1-deamino-1-hydroxyxylostasin, which contains an intermediate of DOS biosynthesis (S-11-P) and has resistance to some aminoglycoside-inactivating enzymes. This is the first finding of antibiotic production by a DOS- mutant without any supplementation of DOS or a DOS analog, and could be described as a novel method of getting a new aminoglycoside antibiotic.

Aminoglycosides↗
PubMed1980

Immunopotentiating effect of fungal glucans as revealed by frequency limitation of postchemotherapy relapse in experimental mouse tuberculosis.

Two kinds of fungal glucan, particulate yeast glucan (PYG) and lentinan, were examined for their immunopotentiating effect illustrated by reduced frequency of post-chemotherapy relapse in experimental mouse tuberculosis. Infected mice were treated by intensive chemotherapy with a three-drug combination [Streptomycin (SM) + isoniazid (INH) + rifampicin (RFP), ethambutol (EB) + INH + RFP, or SM + INH + pyrazinamide (PZA)] for 5 months. After termination of chemotherapy, the mice of each treated group were divided into three subgroups to receive or not to receive glucan for 4 weeks and again for 4 weeks after a month interval. During this 3-month period and the succeeding 5 months, the mice were subjected to occasional sacrifice to examine the growth of latent tubercle bacilli in the lung and spleen by cultivation of tissue homogenates. The results indicated that the regimens with SM + INH + RFP and EB + INH + RFP were highly effective in eliminating persistent tubercle bacilli down to undetectable levels. However, later multiplication of the latent bacilli was observed during the advanced postchemotherapy period. The application of PYG was most effective in prevention of this type of relapse in the spleen, but not so in the lung. Lentinan effect was manifested in the lung, but not in the spleen.

Adjuvants, Immunologic↗
PubMed1980

Phospholipase A2-induced antimycobacterial activity in the membrane fraction obtained from peritoneal exudate cells of guinea pigs.

Tubercle bacilli were preincubated with the membrane fraction separated from casein-induced peritoneal exudate cells of guinea pigs, and subsequently exposed to exogenous phospholipase A2. Marked reduction in viable counts occurred in the incubation mixture at pH 5.6. The additional presence of cholesterol esterase, which alone was inactive, enhanced greatly the phospholipase A2-induced mycobactericidal activity of the fraction. Lipid analysis revealed degradation of phospholipids. The use of cell sap, in place of the membrane fraction, was not only ineffective in the same experimental system, but also neutralized the enzyme-induced activity of the latter. Bacteriostatic effect was also demonstrated in the enzyme-containing Kirchner semi-solid agar medium into which the bacilli were inoculated after being preincubated with the membrane fraction. An additional observation was that the mycobactericidal effect was also revealed when the artificial biomembrane (liposomes) prepared with phospholipids extracted from the exudate cells was used in place of the membrane fraction. These results support such an assumption that toxic fatty acids released from membrane phospholipids have an opportunity to kill the mycobacteria which are in close contact with the membrane.

Agar↗