Biomedical subjects

S Chae

Publications and source records attributed to S Chae.

12 recordsLinked to original sources

PubMed1998

Expressed sequence tags of radish flower buds and characterization of a CONSTANS LIKE 1 gene.

Expressed sequence tag (EST) analysis was conducted for young flower buds of radish plants. Among a total of 66 ESTs examined, 40 showed a significant similarity to previously identified genes. Twenty-eight ESTs were similar to proteins identified in other plants, 11 were similar to eukaryotic proteins other than plants, and one was similar to a prokaryotic protein. Four clones were selected for further studies. EST clone 81, which showed a homology to germin-like proteins was expressed more abundantly in leaves and roots as compared to flower buds. Clone 105 was highly homologous to the translation inhibitor protein and was expressed in all three organs, but the expression level was higher in flower buds and roots. Another EST clone, 133, which shared a significant similarity with the Ran-binding protein, hybridized to two different size transcripts that were detectable only in flower buds. Clone 39 was a homolog of CONSTANS, which is a gene involved in controlling the flowering time in Arabidopsis. The cDNA clone of EST clone 39 containing the entire open reading frame was obtained and designated as RsCOL1 (Raphanus sativus CONSTANS LIKE 1). It was 1049 bp long and contained an open reading frame of 307 amino acid residues (calculated molecular mass = 33.1 kDa). The RsCOL1 protein contained two putative zinc finger motifs in the amino terminal region which were 59% identical to the corresponding region of the Arabidopsis CO protein. The radish protein also contained a predicted nuclear localization domain in the carboxyl terminal region which was 87% identical to the corresponding region of CO. DNA blot analysis revealed that the radish genome contained several genes similar to RsCOL1. RNA blot analysis showed that RsCOL1 was strongly expressed in flower buds at the early bolting stage, and the expression level declined as the flower bud matured. The transcript was also detectable in leaves and roots. In mature flowers, the RsCOL1 transcript was present primarily in carpels.

Amino Acid Sequence↗

PubMed1998

Cloning and sequence analysis of the cDNA encoding the elongation factor-1 beta of Dictyostelium discoideum.

A cDNA encoding elongation factor-1 beta (DdEF-1 beta) for protein synthesis was isolated from Dictyostlium discoideum cells by the differential display (DD) method. The DdEF-1 beta cDNA sequence with a length of 733 bp encodes a protein (M(r) 24.1 kDa) consisting of 214 amino acids. Comparison of the predicted amino acid sequence revealed relatively high homology to that of DdEF-1 beta from silkworm (59%), human (57%) and Xenopus (55%). Northern analysis showed that the DdEF-1 beta mRNA is maximally expressed during the vegetative growth phase, followed by marked decrease in response to cell differentiation induced by starvation.

Amino Acid Sequence↗

PubMed1998

Controlling the judge variable in grading essay-type items: an application of Rasch analyses to the recruitment exam for Korean public school teachers.

The purpose of this paper is to show how the Rasch measurement model can be used to control the effects of judge variable on the grading of essay-type items in the recruitment test for Korean teachers. Special attention is given to two aspects of judges' involvement in the grading. One is to identify a way to minimize the variation of grading due to judge severity. The other concern is to figure out a way to reduce the number of judges without threatening objectivity of ability estimates. Results from the FACETS analyses tell us not only how much grading standards vary among judges and how to adjust them but also it produces comparably reliable ability estimates with fewer judges.

Humans↗

PubMed1992

Lymphoid development in mice congenitally lacking T cell receptor alpha beta-expressing cells.

Vertebrate T cells express either an alpha beta or gamma delta T cell receptor (TCR). The developmental relatedness of the two cell types is unresolved. alpha beta + T cells respond to specific pathogens by collaborating with immunoglobulin-producing B cells in distinct lymphoid organs such as the spleen and Peyer's patches. The precise influence of alpha beta + T cells on B cell development is poorly understood. To investigate the developmental effects of alpha beta + T cells on B cells and gamma delta + T cells, mice homozygous for a disrupted TCR alpha gene were generated. The homozygotes showed elimination of alpha beta + T cells and the loss of thymic medullae. Despite this, gamma delta + T cells developed in normal numbers, and there was an increase in splenic B cells.

Animals↗

PubMed1990

Autonomic indexes during the vestibular-visual conflict exposure: a squirrel monkey study.

To assess the dynamic changes of the autonomic neural responses evoked by vestibular-visual conflict (VVC) in the squirrel monkey, we analyzed the changes of salivary amount and sodium concentration, and the coefficient of variance (CV) of R-R intervals (RRI) along the time course of VVC exposure given in pitch plane. The sodium concentration and the amount of saliva showed clear increases at the first and second 15 min stimulation periods. The CV of RRI was found to increase over the entire periods of stimulation, and there was a significant difference between the rest value and those in stimulated periods. The correlation between the CV of RRI, and amount of salivation was highly positive. These results indicate the existence of a common pattern of autonomic neural response during VVC, and suggest usefulness of these indexes for objectively monitoring the severity of motion sickness.

Animals↗

PubMed1989

Second-phase optokinetic after-nystagmus and vestibular compensation.

To evaluate the direction-specific effect of optokinetic storage function on balance compensation after unilateral labyrinthectomy, squirrel monkeys (n = 12) were exposed to a prolonged (30 min) daily optokinetic stimulus (horizontal, constant speed-90 degrees/sec) for 14 days; either in the ipsilateral direction to the slow phase of spontaneous nystagmus, or in the contralateral direction, or without any optokinetic stimulus. The effect of optokinetic stimulus in ipsilateral direction (slow phase of OKAN-II in the opposite direction) was significantly more (p less than 0.001) in the vestibulo-oculomotor balance (static) regainment than the other two groups, but this group showed the severest gait deviation in the vestibulospinal balance function (p less than 0.05).

Adaptation, Physiological↗

PubMed1973