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Biomedical subjects

A Hayashida

Publications and source records attributed to A Hayashida.

10 recordsLinked to original sources
PubMed2005

Isolation of mutant lines with decreased numbers of chloroplasts per cell from a tagged mutant library of the moss Physcomitrella patens.

Eleven mutant lines exhibiting decreased numbers of chloroplasts per cell were isolated from 8 800 tagged mutant lines of Physcomitrella patens by microscopic observations. Chloronema subapical cells in wild-type plants had a mean of 48 chloroplasts, whereas chloroplast numbers in subapical cells in mutant lines 215 and 222 decreased to 75 % of that in the wild type. Seven mutant lines - 473, 122, 221, 129, 492, 207, and 138 - had about half as many chloroplasts as the wild type. Mutant line 11 had a few remarkably enlarged chloroplasts, and mutant line 347 had chloroplasts of various sizes. Whereas the cell volume was the same as in the wild type in mutant lines 222, 473, 221, 129, 492, and 207, the cell volume of the other mutants increased. The chloroplast number of leaf cells was the same as that of chloronema cells in each mutant line when gametophores could be formed. Treatment with ampicillin decreased the number of chloroplasts in all mutant lines. Southern hybridization using DNA in tags as probes showed that only one insertion occurred in mutant lines 473 and 221. To determine whether the tagged DNA inserted into the known genes for plastid division, we isolated the PpMinD1, PpMinD2, and PpMinE1 genes. Genomic polymerase chain reaction analysis showed that the PpFtsZ and PpMinD/E genes were not disrupted by the insertion of the tags in mutant lines 11 and 347, respectively.

Base Sequence↗
PubMed1982

Effects of the sites of injection of aminoguanidine sulfate on developing eggs.

The difference in biological effects and distribution when aminoguanidine sulfate (AGS) was injected into different sites of developing eggs was studied. (I) Five mg to 20 mg of AGS were injected once into the air sac (AS), albumen (AL) or yolk sac (YS) from the 4th to the 7th day of incubation. Observation continued up to the 18th day of incubation. In the AS group, total mortality was the highest and external abnormalities were most frequent; however, abnormal findings in liver were infrequent and slight. In the YS and particularly in the AL group, on the other hand, liver abnormalities such as low weight, degeneration, necrosis, increase of mitosis, delay of development and fibrosis were found. These are considered as specific effects of AGS. These frequencies were high when AGS was injected on the 4th and 5th day of incubation. (II) Twenty mg injection of AGS into the AS, AL, or YS on the 5th or 8th day of incubation was made for a distribution study. AGS concentration was determined in the various compartments as various times after injection. Distribution of AGS in the AS group was significantly different from that in the AL and YS groups. The AL and YS groups, however, differed a little. The exact route which AGS reaches from the site of injection to the chick embryos could not be determined, but it is concluded that the albumen is the best site for the injection of AGS to investigate its specific effects on liver.

Abnormalities, Drug-Induced↗
PubMed1980

Effects of aminoguanidine sulfate on the incorporation of amino acids and bases into chick embryonic liver and body.

Aminoguanidine sulfate (AGS) produces a peculiar anomaly in the liver of chick embryos. Incorporation of amino acids and bases into the liver and body was investigated to clarify the mechanism of this effect. After chick embryos of White Leghorns were injected with AGS on the 5th day of incubation, 3H-thymidine (3H-T), 3H-uridine (3H-U), 14C-glycine (14C-G) and 14C-leucine (14C-L) were each injected once into the albumen at a specified time from the 5th day to the 8th day of incubation. Incorporation of 3H-T into the liver was markedly reduced in the nuclear (or DNA) fraction, apparently being inhibited at 3 to 6 hr, while incorporation into the body was only slightly affected. Incorporation of 3H-U into RNA was only slightly affected in the liver 24 hr after injection, while incorporation into the body did not differ from control. Incorporation of 14C-G was remarkably reduced with AGS both in the liver and body protein, and the degree of inhibition was around 26-52% at 3 or 24 hr. Incorporation of 14C-L, however, was reduced only in the liver, and became pronounced on the 8th or the 9th day of incubation. The primary action AGS seems to be on nucleoprotein synthesis; namely, on inhibition of DNA synthesis. Those findings are discussed, through comparison of histopathological observations.

Amino Acids↗