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Biomedical subjects

K Kamo

Publications and source records attributed to K Kamo.

13 recordsLinked to original sources
PubMed2004

Dispersal and size fractionation of embryogenic callus increases the frequency of embryo maturation and conversion in hybrid tea roses.

Plant regeneration from embryogenic cells of two Rosa hybrida cultivars, Kardinal and Classy, was increased by dispersing embryogenic callus in liquid medium for 3 h followed by size-fractionation to isolate proembryogenic masses that were smaller than 530 microm. Dispersed callus of three cultivars, Kardinal, Classy, and Tineke, produced 61-135 cotyledonary-stage embryos/100 mg fresh weight (FW) as compared to intact callus that had not been dispersed, which produced only zero to three cotyledonary-stage embryos/100 mg FW. Over 500 cotyledonary-stage embryos/100 mg FW callus developed from proembryogenic masses of Kardinal, Classy, and Tineke following 2 months of culture on solidified Murashige and Skoog's basal salts medium supplemented with 0.25% activated charcoal. Cotyledonary-stage embryos of Classy that developed from both dispersed callus and fractionated cells of various sizes showed a significantly higher conversion frequency to plants (28%) than cotyledonary-stage embryos isolated from intact callus (9%). The highest conversion frequencies for Kardinal (50-58%) occurred from cotyledonary-stage embryos that developed from dispersed callus and from the fraction of cells smaller than 850 microm.

Cotyledon↗
PubMed2001

Characterization of mutants defective in melanogenesis and a gene for tyrosinase of Streptomyces griseus.

Nitrosoguanidine-induced melanin-negative mutants of Streptomyces griseus were classified according to their ability to produce streptomycin and A-factor, and to form aerial mycelium. A large proportion of the mutants showed deficiency in either antibiotic production and morphological development or both, suggesting close regulatory correlation between melanogenesis and morphological and physiological differentiation. The tyrosinase-encoding mel operon of S. griseus was cloned and examined for its role in melanogenesis of this organism. As in other Streptomyces homologues, the operon consisted of two open reading frames, melC1 encoding the putative cofactor and melC2 encoding the tyrosinase. Regardless of the distinct sequence similarity, introduction of the operon on plasmids failed to confer melanin production in the melanin-negative mutants, and the disruption of melC2 barely affected the melanin productivity, which indicated the presence of another enzyme involved in the melanogenesis in S. griseus. On the other hand, mel on a high-copy-number plasmid caused precocious aerial mycelium formation in Streptomyces lividans TK21 suggesting a stimulatory role of tyrosinase in morphological development.

4-Butyrolactone↗
PubMed1995

A longitudinal follow-up study of seasonal affective disorder.

OBJECTIVE: The purposes of this study were to evaluate the long-term stability of a seasonal pattern of recurrent depression, identify possible factors associated with alteration of the seasonal pattern, and determine whether atypical vegetative symptoms during early seasonal depressive episodes predict future seasonal relapses. METHOD: The subjects were 41 patients satisfying the criteria used in the Japanese multicenter study of seasonal affective disorder who were consistently treated at the same outpatient clinic. Their longitudinal courses were evaluated by using case records and the Schedule for Affective Disorder and Schizophrenia--Life-time Version; the mean follow-up period was 10.4 years. RESULTS: Nine subjects (22.0%) consistently showed a fall-winter pattern of recurrence throughout follow-up. Seventeen patients with an initial fall-winter pattern subsequently tended to shift seasons or show less seasonality. This alteration in pattern was possibly associated with antidepressant therapy or life events. Eleven patients with an initial diagnosis of nonseasonal affective disorder subsequently developed seasonal affective disorder; no specific factors were associated with this change. Atypical vegetative symptoms were significantly more common in patients with stable seasonal patterns of recurrence than in those who lost seasonality. CONCLUSIONS: Although seasonal affective disorder appeared to be altered by antidepressant treatment, the presence of a core group of patients with a consistent seasonal pattern of recurrent depression suggests the validity of seasonal affective disorder as a distinct subtype of recurrent affective illness. The findings also suggest that atypical vegetative symptoms during early seasonal depressive episodes predict the subsequent seasonality of depression.

Adult↗
PubMed1992

Development of a monoclonal antibody to the conserved region of p34cdc2 protein kinase.

Mice and rabbits were injected with various forms of a 16 amino acid synthetic peptide representing PSTAIR, the evolutionarily conserved region of the protein kinase p34cdc2, for polyclonal antisera and hybridoma-monoclonal antibody production. Antisera from mice injected with an unconjugated monomeric form of the peptide showed no reaction to the peptide. Of four animals injected with the monomeric form of the peptide conjugated to keyhole limpet hemocyanin via m-maleimidobenzoyl-N-hydroxysulfosuccinimide (MBS), antisera from only one mouse had a very low titer to the peptide, and all four animals produced antibody to the MBS bridge. Both mice injected with an octameric multiple antigen peptide (MAP) of PSTAIR produced antisera reactive to the octameric MAP form of the peptide in ELISA and also to the cdc2 protein expressed in bacteria in an immunoblotting assay. Splenocytes from one mouse injected with the octameric MAP form of the peptide were successfully used for hybridoma-monoclonal antibody production. A monoclonal antibody was produced that reacted with octamer, monomer and cdc2-expressed protein and specifically with the carboxyl terminus of the 16 amino acid peptide.

Amino Acid Sequence↗
PubMed1983

Comparative study on the mechanical property of silk thread from cocoons of Bombyx mori L.

Specimens of bave (undegummed silk thread) were collected from cocoons of various origins of parent silkworm races, such as Japanese, Chinese, European, Korean and tropical origins, and from as many races as possible. An apparatus was set up to measure the dynamic elastic modulus of these specimens. In all the categories of the races tested, the elastic modulus was linearly related to the size of bave, regardless of the portion of cocoon layer from which the specimens were taken. This correlation was concluded to be universal to the silk thread of Bombyx mori L. species; however, values of the regression coefficient and of the elastic modulus were susceptible to the origin of silkworm races, depending on whether they were native or improved.

Animals↗