Biomedical subjects

Koichiro Shimomura

Publications and source records attributed to Koichiro Shimomura.

14 recordsLinked to original sources

PubMed2005

Characterization of lucidin formation in Rubia tinctorum L.

In order to approach lucidin formation (a strong mutagen or a carcinogen) from a physiological standpoint, hairy roots of Rubia tinctorum L. were established by a transformation of Agrobacterium rhizogenes strain 15834 and cultured in a liquid woody plant medium without plant hormones. The anthraquinone pigment composition of the intact hairy roots was essentially the same as that of the intact non-transformed (normal) roots, in which lucidin O-beta-D-primeveroside (LuP) was one of the major pigments. Lucidin was scarcely detected in the intact hairy roots, but was a main pigment after the squash treatment. The crude protein extract of intact hairy roots exhibited LuP-glycosidase activity (an activity converting LuP to lucidin). This activity was also detected in the roots of the normal plants at a high level, but slightly in the stems and not in the leaves. Methyl jasmonate enhanced the LuP production and LuP-glycosidase activity in the hairy roots. On the other hand, ethephon or salicylic acid had either no effect or rather an inhibitory effect on them. After partial purification of LuP glycosidase, the resultant active fraction producing a major band with an apparent Mr of 68 kDa exhibited the substrate specificity for both aglycon and sugar-moiety. The sugar released from LuP by this fraction was neither D-glucose nor D-xylose and was hydrolyzed into them. These results suggest that LuP specific beta-primeverosidase (EC 3.2.1.149) exists in the roots of R. tinctorum and is involved in the systematic defense system.

Anthraquinones↗

PubMed2005

Ethylene induced shikonin biosynthesis in shoot culture of Lithospermum erythrorhizon.

Lithospermum erythrorhizon shoots, cultured on phytohormone-free Murashige and Skoog solid medium, produced shikonin derivatives, whereas shoots cultured in well-ventilated petri dishes, produced small amount. Analysis by gas chromatography revealed the presence of ethylene in non-ventilated petri dishes where the shoots, producing shikonin derivatives, were cultured. Therefore, the possible involvement of ethylene in shikonin biosynthesis of shoot cultures was investigated. Treatment of ethylene or the ethylene precursor, 1-aminocyclopropane-1-carboxylic acid, resulted in increasing shikonin derivatives contents in cultured shoots. Silver ion, an ethylene-response inhibitor, or aminoethoxyvinylglycine, an ethylene biosynthesis inhibitor, decreased production of shikonin derivatives in cultured shoots. Our results indicate that ethylene is one of the regulatory elements of shikonin biosynthesis in L. erythrorhizon shoot culture.

Amino Acids, Cyclic↗

PubMed2005

A rapid and reliable solid-phase extraction method for high-performance liquid chromatographic analysis of opium alkaloids from papaver plants.

A rapid and reliable solid-phase extraction method for HPLC analysis of opium alkaloids from Papaver plants was established. Fifty mg of dried and powdered plant sample was extracted with 5 ml of 5% acetic acid for 30 min under sonication. After centrifugation, 3 ml of the supernatant was loaded on a reversed-phase cation-exchange solid-phase extraction cartridge. After seriate washings with 0.1 M hydrochloric acid and methanol, alkaloids were eluted with a mixture of 28% ammonia and methanol (1:19). The eluate was concentrated under nitrogen stream at 40 degrees C and the residue was dissolved in 50% aqueous methanol for high performance liquid chromatographic analysis. With this solid-phase extraction method, the recovery of morphine, codeine, oripavine, thebaine, papaverine, noscapine and sanguinarine was from 99.94 to 112.18% when the standard alkaloids were added to the plant samples. Opium alkaloids of a variety of genus Papaver plants cultivated in a field and phytotron were analyzed by this method.

Alkaloids↗

PubMed2004

Tropane alkaloid production and shoot regeneration in hairy and adventitious root cultures of Duboisia myoporoides-D. leichhardtii hybrid.

Co-culture conditions for Duboisia myoporoides-D. leichhardtii hybrid hairy root induction were investigated using leaf explants and Agrobacterium rhizogenes ATCC 15834. The bacteria density and duration of co-culture greatly affected the induction rate; the highest rate of 50% was obtained when the leaf explants were co-cultured for 2 d with 10(6) bacteria. One hairy root clone that showed the fastest root growth was selected and used for comparison study with adventitious roots cultured with 0.5 mg/l indole-3-acetic acid (IAA). The hairy roots cultured in Murashige and Skoog (MS) liquid medium grew well and yielded much more tropane alkaloids (35 mg/l scopolamine and 17 mg/l hyoscyamine) than adventitious roots cultured in 0.5 mg/l IAA after 6 weeks of culture at 25 degrees C in the dark. The hairy and adventitious roots (2.5 cm) grown in liquid media were divided into 5 parts (each 0.5 cm) along the root axis. Distribution of scopolamine and IAA was then determined by enzyme-linked immunosorbent assay (ELISA). Inverse relationship between contents of scopolamine and IAA was observed in the hairy roots; increase of scopolamine and decrease of IAA were proportional to the distance from the root meristem. In contrast, the contents of scopolamine and IAA were relatively constant in the adventitious roots. In shoot regeneration experiments, the hairy and adventitious root segments (1 cm) were placed onto 1/2 MS solid medium containing various concentrations of IAA and BA cultured at 25 degrees C under 16 h light. In adventitious roots, the shoots regenerated on media containing 6-benzyladenine (BA) (0.5 to 5 mg/l), and 100% regeneration was observed in medium with 0.1 mg/l IAA and 2 mg/l BA. On the other hand, shoot regeneration was only observed in 33% of hairy roots cultured on medium containing 5 mg/l BA.

Alkaloids↗

PubMed2004

Auxins affected ginsenoside production and growth of hairy roots in Panax hybrid.

Hairy roots of interspecific hybrid ginseng (Panax ginseng x P. quinquefolium), induced by Agrobacterium rhizogenes ATCC 15834, grew well in B5 liquid media supplemented with 2.5 microM auxins (3-indole butyric acid (IBA), 1-naphtaleneacetic acid (NAA) and 3-indoleacetic acid (IAA)). The hairy roots cultured in B5 liquid medium supplemented with 2.5 microM IBA showed best growth (6.39 g fresh weight per a flask, at week 8). The highest content of the total ginsenosides was 1.63% as dry weight at week 8 when cultured with 2.5 microM NAA. The different auxins affected the numbers and lateral branching roots. Especially, 2.5 microM IBA promoted the lateral root formation (43.7+/-4.0 roots, at week 8), and 2.5 microM NAA promoted the lateral root growth (45.3+/-5.6 mm, at week 8). The growth and ginsenosides production of 8-week old hairy roots cultured in B5 liquid media supplemented with IBA and NAA combinations were also investigated. Hairy roots produced higher amounts of ginsenosides in B5 liquid media supplemented with 0.5-1.0 microM IBA and NAA combinations than that cultured in B5 liquid media supplemented with only IBA and NAA. The highest yield of ginsenoside was obtained when cultured with 0.5 microM IBA and 1.0 microM IBA combination (6.38 mg per a flask, at week 8).

Culture Techniques↗

PubMed2003

New insights in muon-catalyzed dd fusion by using ortho-para controlled solid deuterium.

For the first time, we observed the dependence of the ddmu formation rate and the dmu hyperfine-transition rate on the ortho-para state in muon-catalyzed fusion in the solid D2 state, and found that the effect is even opposite to a recent theoretical prediction. We also determined the back-decay rate and the hyperfine-transition rate via scattering in solid state by using the ortho-para dependence. A theory to describe properly our experimental result is called for to understand the nature of muon-catalyzed fusion in the solid state.

Journal Article↗

PubMed2003

Transformation of ipecac (Cephaelis ipecacuanha) with Agrobacterium rhizogenes.

Transformed root cultures of ipecac (Cephaelis ipecacuanha A. Richard), one of the recalcitrant woody plant species for Agrobacterium-mediated transformation, were established by co-culturing of in vitro petiole segments with Agrobacterium rhizogenes ATCC 15 834. Southern blot analysis of the established roots revealed that only the TL-DNA was integrated into the plant genome without incorporation of the TR-DNA. The transformed roots grew slowly on phytohormone-free solid medium and adventitious shoots were regenerated after over 6 months of culture on HF, half-strength Murashige and Skoog (1/2 MS) medium in the dark. The individually separated transformed shoots developed into plantlets on phytohormone-free solid medium at 25 degrees C under 16 h/day light, and the plants demonstrated wider leaves, shorter internodes and vigorous root growth compared to non-transformed plants. Effects of basal media and auxins on the growth and the ipecac alkaloid production of the transformed roots were investigated either under light or in the dark. The roots cultured in the dark grew well in Gamborg B5 (B5) liquid medium containing 0.5 mg/L IBA and yielded 112 mg/L of cephaeline and 14 mg/L emetine after 8 weeks of culture.

Blotting, Southern↗

PubMed2003

Polyacetylenes in hairy roots of a panax hybrid.

From the hairy roots of an interspecific hybrid ginseng ( Panax ginseng x P. quinquefolium) known as Pgq, three polyacetylenes were isolated: panaxynol, panaxydol and 1,8-heptadecadiene-3,10-diol. These compounds isolated from the hairy roots were used for quantitative analysis to investigate the polyacetylene production of the hairy roots cultured in Gamborg B5 (B5) and 1/8 Murashige-Skoog (MS) liquid media. Maximum growth of the hairy roots was observed (ca. 5.4 g fresh weight/100 mL flask) at 8 weeks of culture in B5 medium. The highest total content of total polyacetylenes was 0.18 % of dry weight at week 8 when cultured in 1/8 MS medium. In addition, we compared the yields of polyacetylenes and ginsenosides in hairy roots cultured in B5 with those in 1/8 MS media and found the highest yields were obtained in the hairy roots cultured in B5 medium (1.24 mmol/flask polyacetylenes and 4.45 mmol/flask ginsenosides at week 8).

Acetylene↗

PubMed2003

[Influence of fertilizers on yield and yield components of opium from Papaver somniferum Linn].

The effect of fertilizer on the yield and yield components of opium from Papaver somniferum L.cv.Ikkanshu were investigated from 1993 to 1995. The weight of opium per one capsule was tendency to increase in the order of peat moss > pulverized charcoal > compound fertilizer, but the differences among the results were not significant. Furthermore, no difference in the capsule weight per 100 m2 and the yields of opium and alkaloids per 100 m2 were detected. The significant difference was only observed when the data were compared among the weights and yields of different years. The difference among the yield of opium was mainly due to the weight of opium per one capsule. The weight of opium per one capsule showed a high correlation with capsule husk weight. The alkaloids contents in opium obtained with a different fertilizer application showed no difference. Morphine content at the first lancing was about 11%, and the value decreased with the order of lancing. On the contrary, the codeine and the thebaine content did not change during lancing and the value were 6-7% and 3%, respectively. The papaverine and the noscapine content decreased in the order of lancing.

Codeine↗

PubMed2002

Electronic structure of the muonium center as a shallow donor in ZnO.

The electronic structure and the location of muonium centers (Mu) in single-crystalline ZnO were determined for the first time. Two species of Mu centers with extremely small hyperfine parameters have been observed below 40 K. Both Mu centers have an axial-symmetric hyperfine structure along with a <0001> axis, indicating that they are located at the antibonding (AB(O, parallel )) and bond-center (BC( parallel )) sites. It is inferred from their small ionization energy ( approximately 6 and 50 meV) and hyperfine parameters ( approximately 10(-4) times the vacuum value) that these centers behave as shallow donors, strongly suggesting that hydrogen is one of the primary origins of n type conductivity in as-grown ZnO.

Journal Article↗

PubMed2002

Salicylic acid carboxyl methyltransferase induced in hairy root cultures of Atropa belladonna after treatment with exogeneously added salicylic acid.

In Atropa belladonna hairy roots, exogeneously added salicylic acid (SA) is converted to methyl salicylate (MSA) through the reaction, which might be catalysed by S-adenosyl-L-methionine: salicylic acid carboxyl methyltransferase (SAMT). Here we cloned a cDNA for A. belladonna SAMT (AbSAMT1), which consisted of 357 aa residues. It was expressed in E. coli, and the recombinant AbSAMT1 showed SAMT activity. When A. belladonna hairy roots were exposed to a high concentration of SA, AbSAMT1 mRNA begins to be expressed 12 h after the exposure, and steady expression continued over 144 h.

Amino Acid Sequence↗

PubMed2002

Tropane alkaloids in adventitious root cultures of Physochlaina physaloides.

Adventitious root cultures of Physochlaina physaloides were established and their growth and tropane alkaloid production were investigated. Although the roots cultured in Murashige-skoog liquid medium containing 1.0-3.0 mg/l IBA grew well, the addition of lower concentrations of auxins was more suitable for alkaloid production. The best alkaloid yield was obtained with 0.01 mg/l NAA in 1/2 MS liquid medium. In addition, the alkaloid differences between the cultured roots and the regenerated plant cultivated in the soil was studied. Cultured roots in this condition showed higher level of alkaloids when compared to leaf, stem and roots from the regenerated plant (3 months in field conditions).

Culture Media↗

PubMed2002

Tropane alkaloids in auxin-independent root cultures of Physochlaina physaloides.

Adventitious and hairy root cultures of Physochlaina physaloides were established. These roots grew well and produced high amounts of tropane alkaloids (particularly hyoscyamine and 6 beta-hydroxyhyoscyamine) in auxin-free culture medium. The effects of basal media and temperature on the growth and alkaloid production of these roots were investigated. Both root cultures produced highest amount of tropane alkaloids in B5 medium though the optimum temperature for hairy roots were lower than that for adventitious roots.

Culture Media↗

PubMedDate not supplied

Characteristics of Atropa belladonna hairy roots cryopreserved by vitrification method.

Atropa belladonna hairy roots (clone M8) were successfully cryopreserved by using the vitrification method. A. belladonna hairy root tips were precultured on a half strength of Murashige and Skoog (MS) solid medium with 0.1 mg per L 2,4-D or without phytohormone for 1 day, and then dehydrated with PVS2 solution for 15 minutes prior to immersion into liquid nitrogen for 1 day, 1 week, 1 month and 3 months. Hairy root tips kept in liquid nitrogen were rapidly thawed at 36 degree C in a water bath. The root tips were recultured on half strength MS medium. The hairy root tips, precultured with 2,4-D before cryopreservation, showed a higher survival rate than those precultured without phytohormone. The hairy root tips, precultured with 2,4-D, showed an average survival rate of 83 percent. There was no significant difference in the viability of the hairy roots cryopreserved for different periods. The regrowth of cryopreserved hairy roots was similar to that of untreated hairy roots and tropane alkaloid productivity became stable after 4th subculture. PCR analysis of hairy roots demonstrated the conservation of the T-DNA in cryopreserved hairy roots. These results indicate that cryopreservation by vitrification method is useful to preserve A.belladonna hairy root clone M8.

Atropa belladonna↗