Biomedical subjects
Publications and source records attributed to S Yamaguchi.
Salmonella typhimurium mot mutants are unable to rotate their flagella. Dark-field light microscopy showed that the flagella could be rotated passively by an external rotatory driving force.
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Rhode Island Red laying hens were inoculated with the JPA-1 strain of egg drop syndrome-1976 virus and examined pathologically 1, 3, 5, 7, 10, 14, 21, 28 and 80 days postinoculation (p.i.). Eggs with a discolored or soft shell or no shell were laid over a period from 10 to 24 days p.i. Egg production failed transiently in some affected birds after 13 days p.i. At autopsy, the uterus revealed remarkable edema and swelling of the mucosal folds together with the deposition of whitish exudate in the cavity 14 days p.i. Microscopically, intranuclear inclusion bodies were found in epithelial cells of the uterus, isthmus and vaginal gland region 10 and 14 days p.i. There were also severe degeneration and desquamation of the epithelial cells, atrophy of the uterine glands and remarkable infiltration of heterophils, lymphocytes and plasmacytes accompanied with extensive edema. Twenty-one days after inoculation, lymphoid follicles were formed in the mucosal folds of some part of the oviduct. Electron microscopic examination revealed various amounts of virus particles 68 approximately 80 nm in diameter mainly in the nuclei of the epithelial cells on the mucosa and in the exudate, and also in the cytoplasm of macrophages in the uterus.
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Polyhooks were isolated from Salmonella SJW880, a non-flagellated mutant, and purified by cesium chloride density gradient centrifugation. The polyhooks were disintegrated into protein subunits (monomer) by heat in the absence of salt. The monomer was repolymerized in the presence of moderately high concentrations of sodium citrate at neutral pH. Three types of polymer were produced. One type of polymer, produced at room temperature and at citrate concentrations less than 0.3 M, had no regular shape and no definite thickness. Another type of polymer, produced at room temperature and at citrate concentrations greater than 0.4 M, had a straight shape and a similar thickness to that of polyhook but was easily dissociated into monomer in the absence of salt. A third type of polymer was produced at low temperature, independently of the concentration of citrate, and seemed to be a tubular polymer with a thickness similar to that of polyhook but had no helical curvature. However, this type of polymer was shown to have a structure locally the same as that of polyhook by electron microscopic observation, optical diffraction and circular dichroism measurements.
Bacterial flagella undergo transition between several discrete types of left-handed and right-handed helical structures when exposed to acidic or alkaline pH, or to mechanical force. Calladine and ourselves have presented models to explain such polymorphism, assuming that protein subunits (flagellin) in a flagellum can be transformed into two conformations (L- and R-states) depending on the species of flagellin and on the environmental conditions. An obvious prediction from these 'two-state' models is that there should be two types of straight flagella (L- and R-types) that are made up exclusively of flagellins in either the L-state or the R-state. We have shown that straight flagella from two species of mutants, Salmonella SJ814 (ref. 6) and Escherichia coli hag 177 (ref. 7), are closely similar to the predicted R- and L-types, respectively. Recently we have isolated 10 strains of straight-flagellar mutants of Salmonella. We show here that their flagella can also be classified into the L- and R-types, and that copolymerization of flagellins from two heterologous types (L and R) makes discrete types of helical filaments, whereas that of homologous pairs of flagellins (L and L, or R and R) makes only straight filaments.
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A continuous frontal analysis chromatographic method was developed for studying the simultaneous binding of two drugs or ligands with an immobilized macromolecule. The usefulness of this method was demonstrated in the interactions of sulphamethizole and salicylic acid with human serum albumin (HSA). The mutual inhibitory effect on the binding of one drug of the presence of the other was directly shown to be due to displacement of the bound drug from HSA by the other. On the basis of a double-reciprocal plot analysis, these two drugs are interpreted as competing for the same primary binding sites.
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Histologic investigation and analysis of 370 polyps, removed via colonoscope, demonstrated a malignancy rate of adenomas of about 20 per cent. Even small adenomas under 1 cm in diameter were found to have a higher malignant potential than previously appreciated. The malignancy rate was higher with increasing size, and adenomas in females had a much higher malignant potential than in males. It is obvious that colonoscopic polypectomy is valuable in detecting and treating early carcinomas of the colon.