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Biomedical subjects

Y Sano

Publications and source records attributed to Y Sano.

At least 433 records · Page 24Linked to original sources
PubMed1981

Purification and properties of an S-type pyocin, pyocin AP41.

Pyocin AP41, a protease-sensitive bacteriocin produced by Pseudomonas aeruginosa PAF41, was purified to a homogeneous state and characterized. The molecular weight of this pyocin was about 95,000 as determined by the combination of gel filtration and sedimentation velocity analysis. This pyocin was a complex of two kinds of polypeptides. Highly purified preparations showed two protein bands on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and their apparent molecular weights were 90,000 and 6,000 to 7,000, respectively. Two proteins could be separated by gel filtration in the presence of 6 M urea. Amino acid compositions of these components were determined. The large component had pyocin activity similar to the complex, whereas the small component did not. Sensitive cells were killed by this pyocin only under growing conditions and with single-hit kinetics. The pyocin-treated cells lysed in about 30 min with concomitant production of their resident pyocins or phages. The induced production of resident pyocins caused by pyocin AP41 depended on a recA gene function.

Amino Acids↗
PubMed1981

Changes in enzyme activities related to steroidogenesis in human ovaries during the menstrual cycle.

Follicles and corpora lutea were isolated from the ovaries of 25 patients at several stages of the normal menstrual cycle. To measure the steroidogenic enzyme activities, cell-free homogenates of the ovaries were incubated aerobically with 4-14C-labeled pregnenolone, progesterone, 17 alpha-hydroxyprogesterone, androstenedione, and testosterone in the presence of appropriate cofactor(s). The delta 5-3 beta-hydroxysteroid dehydrogenase plus delta 4-delta 5 isomerase activity in the follicle was low during early follicular phase (greater than 11 days before ovulation), but gradually increased toward ovulation and showed maximal values in the corpus luteum at the midluteal phase (6-10 days after ovulation). The activities of 17 alpha-hydroxylase and C-17-C-20 lyase in the follicle reached the highest value at the late follicular phase (within 5 days of ovulation), but markedly decreased after luteinization. 17 alpha-Hydroxylase activity in the corpus luteum increased again during the midluteal phase, whereas the activity of C-17-C-20 lyase remained at a low level throughout the luteal phase. The aromatase activity was low during the follicular phase, but increased markedly with luteinization. These findings are discussed in light of the known plasma steroid concentrations and their changes during the menstrual cycle.

3-Hydroxysteroid Dehydrogenases↗
PubMed1981

Differential response to elutriated 9L cells to treatment with 1,3-bis(2-chloroethyl)-1-nitrosourea.

Earlier cytokinetic studies using 9L monolayer culture cells showed that cells began accumulating in the G2 phase (4C position in the DNA distribution) within 30 hr after administration of 1,3-bis(2-chloroethyl)-1-nitrosourea (3 micrograms/ml). Most of these cells reached the G2 phase at 48 hr and remained there for another 24 hr. Similar studies using 9L spheroid culture cells show that 9L cells also began to accumulate at the 4C DNA position 30 hr after administration of 1,3-bis(2-chloroethyl)-1-nitrosourea (3 micrograms/ml); however, only one-half of the cells accumulated in the 4C peak during the first 48 hr after treatment, while the other half remained at the 2C position. Those that remained at the 2C peak might correspond to the G0 cells that exist in 9L spheroids. When one-half the cells were in 2C and one-half were in 4C, the spheroids were dissociated using an enzyme cocktail and sorted using centrifugal elutriation. Cells from each elutriated fraction were analyzed for DNA content using flow cytometry and for viability using a colony-forming efficiency assay. Results indicated that in spheroids, 1,3-bis(2-chloroethyl)-1-nitrosourea (3 micrograms/ml) is more effective against noncycling cells and that repopulation is more vigorous in G2-arrested cells, which presumably were cycling at the time of treatment.

Animals↗
PubMed1980

Morphological and functional peculiarities of mesenchymal cells in the pars tuberalis of the pituitary gland.

Following injection of high doses of horseradish peroxidase (HRP), mesenchymal cells distributed in the perisinusoidal space of the pars tuberalis of the hypophysis in cats, rabbits and Japanese quails, sequester the exogenously administrated peroxidase intensively. These cells are designated by the authors as "horseradish peroxidase-uptake cells" (HRP-uptake cells or HUC). HRP-uptake cells constitute a system of macrophages in the pars tuberalis of mammals and birds, and are located around the hypophysial portal veins. HRP-uptake cells differ in morphological and functional characteristics from similar cells in other parts of hypophysis. They are thought to play a role in the hypothalamic control of adenohypophysial secretion.

Animals↗
PubMed1980

Dopamine and alpha-endorphin are contained in different neurons of the arcuate nucleus of hypothalamus as revealed by combined fluorescence histochemistry and immunohistochemistry.

An attempt was made to demonstrate dopamine and alpha-endorphin neurons in the same sections of the arcuate nucleus by combining the techniques of fluorescence histochemistry and immunohistochemistry. Dopamine neurons were found mainly in the medial part near the wall of the third ventricle and alpha-endorphin neurons in the lateral part. We failed to detect any neurons showing simultaneous dopamine fluorescence and alpha-endorphin positive immunoreactivity. We conclude therefore that dopamine synthesizing neurons are probably different from alpha-endorphin synthesizing neurons in the arcuate nucleus.

Animals↗
PubMed1980

Light scattering studies on alpha-crystallin from bovine eye lens.

Using the usual angular light scattering technique, we have measured the concentration dependence of reduced scattering intensity of fractionated bovine lens alpha-crystallin (alpha A-chain) in the presence of 30 mM calcium chloride and 0.1 M sodium chloride. The inverse intensity of scattered light at zero angle per unit concentration of alpha-crystallin has a significant upward curvature with increasing alpha-crystallin concentration. The third virial coefficient determined from this upward curvature was 1.24 x 10(-3) (mol 1/2 ml 1/2 g-1).

Animals↗
PubMed1980

Kinetic analysis of bovine alpha-crystallin reaggregation in the presence of calcium ions.

The kinetics of alpha-crystallin reaggregation in the presence of calcium ions were investigated by monitoring changes in optical density at 320 nm. alpha-Crystallin showed a critical concentration. In the initial stages, reaggregation and deaggregation of alpha-crystallin may be essentially fully reversible in the presence of high levels of calcium ions. The initial rate of reaggregation was strongly calcium ion-dependent. The kinetics of alpha-crystallin reaggregation revealed a pseudo-first order time dependence. This is most easily explained by postulating very rapid formation of the initial complex for alpha-crystallin reaggregation (nucleation). These studies indicate that reaggregation of alpha-crystallin occurs by a pathway involving a nucleation phase followed by an elongation phase, that the formation of the small active initiator, presumably alpha-crystallin dimer or some species formed from it (i.e., intermediate high molecular weight component) is very fast, and that the growth of these active initiators is biphasic.

Animals↗
PubMed1980

Light scattering studies on the reaggregation and deaggregation of bovine alpha-crystallin in the presence of calcium ions.

The concentration dependence of reduced scattering intensity of fractionated bovine lens alpha-crystallin was observed in the presence of various concentrations of calcium ions, using the usual angular light scattering technique. The intensity of scattered light at zero angle per unit concentration of alpha-crystallin increased sharply with increase of the calcium ion concentration, reaching a maximum at about 50-60 mM, and then decreasing rapidly at calcium levels above 60 mM. This indicates that reaggregation and deaggregation of alpha-crystallin occur in the presence of calcium ions. Application of light scattering analysis showed the inverse intensity of the scattered light to have a significant upward curvature with increasing alpha-crystallin concentration. The third virial coefficient determined from this upward curvature was very high at low calcium concentrations, and then decreased monotonously with increase of the calcium ion concentration. It was almost zero over the high concentration of 50 mM Ca2+.

Animals↗
PubMed1980

Aggregation of tobacco mosaic virus by sodium chondroitin sulfate.

The precipitation of tobacco mosaic virus by sodium chondroitin sulfate in an aqueous solution was investigated kinetically by means of turbidimetry. The virus solution became turbid after the addition of chondroitin sulfate. A threshold concentration of chondroitin, 1.33 mg/ml, was required for virus precipitation, irrespective of the virus concentration. The precipitation resulted from a mutual spatial exclusion phenomenon, leading to the separation of the virus as a crystalline phase. The dimension of chondroitin sulfate calculated at the threshold concentration agreed well with that obtained by other methods. The initial slopes and the aggregation half-times of the virus aggregates depended on both chondroitin and virus concentrations and the former increased with the increase in concentration of each. Above the threshold concentration of chondroitin sulfate, tobacco mosaic virus aggregation was a rapid-aggregation process and ended within 100 sec.

Antiviral Agents↗
PubMed1980

Steroid 16 alpha-hydroxylase from human fetal liver; inhibition by steroids.

The 16 alpha-hydroxylase system in fetal liver which used dehydroepiandrosterone (DHA) or pregnenolone as substrate, was apparently inhibited by various endogenous and synthetic steriods: DHA, pregnenolone, their sulfates, androstenediol, androstenetriol, estrone, estradiol-17 beta, ethynylestradiol and chlormadinone-acetate. The inhibition constants (Ki) towards DHA were as follows; pregnenolone 22 muM, DHA-sulfate 13 muM, pregnenolone-sulfate 21 muM, androstenediol 16 muM, androstenetriol 53 muM estrone 32 muM, estradiol-17 beta 74 muM, ethynylestradiol 22 muM and chlormadinone-acetate 27 muM. The Ki values towards pregnenolone were DHA 6.3 muM, DHA-sulfate 8.3 muM, pregnenolone-sulfate 3.9 muM, androstenediol 8.7 muM, androstenetriol 14.7 muM, estradiol-17 beta 15.4 muM and ethynylestradiol 16.0 muM, respectively. The reaction products, 16 alpha OH-DHA and 16 alpha OH-pregnenolone, showed little inhibitory effect upon the 16 alpha-hydroxylase.

17-alpha-Hydroxypregnenolone↗
PubMed1980

Failure to detect papovavirus-associated T antigens in human brain tumor cells by anticomplement immunofluorescence.

To probe the possible presence of papovavirus-related T antigen(s) in human brain tumors, the imprinted or cultured cells at various passage levels were examined by anticomplement immunofluorescence using antisera to T antigen of each BK virus, JC virus, and simian virus 40. No T antigen was demonstrated in any tests with cells derived from 69 patients with various brain tumors. Twenty-two tumor cell strains cultured in the presence of a tumor promoter, phorbol ester, also failed to show the T antigen.

Animals↗