Identification and mapping of a quantitative trait locus controlling extreme late bolting in Chinese cabbage (Brassica rapa L. ssp. pekinensis syn. campestris L.) using bulked segregant analysis     

Hidetoshi Ajisaka  Yasuhisa Kuginuki  Susumu Yui  Sueo Enomoto  Masashi Hirai 《Euphytica》2001,118(1):75-81

DNA markers linked to a locus controlling an extreme late bolting trait, which was originally found in a local cultivar of a non-heading leafy vegetable,‘Osaka Shirona Bansei’ (Brassica rapa L. ssp. pekinensis syn. campestris L.) were identified using bulked segregant analysis. A doubled haploid (DH) line, DH27, which is a progeny of ‘Osaka Shirona Bansei’, shows extreme late bolting, and bolts without vernalization. DH27 was crossed with a normal bolting DH line, G309. The plantlets of the parents, F₁ and F₂, were vernalized and then grown in a greenhouse. The bolting time of F₂ plants showed a continuous distribution from 19 to 231 days after vernalization (DAV), suggesting the effects of a few major genes and polygenes. Possible linkage markers for this trait were screened by modified bulked segregant analysis (BSA). The BSA using four bulks suggested that a 530-bp RAPD band RA1255C was linked to a locus controlling the bolting trait. The RAPD band was cloned and used as a probe to detect RFLP. The fragment detected a single locus, BN007-1,the segregation of which in the F₂ population matched that of RA1255C. Three other RAPDs were found to be linked to BN007-1. A quantitative trait locus(QTL) affecting the bolting time was detected around BN007-1 using MAPMAKER/QTL. Since the difference between bolting times of both the parental genotypes in the F₂ was 138 days, these markers may be useful for a marker-assisted selection (MAS) in the breeding program for late bolting or bolting-resistant cultivars in B. rapa crops. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Tracking FACT and the RNA polymerase II elongation complex through chromatin in vivo     

Saunders A  Werner J  Andrulis ED  Nakayama T  Hirose S  Reinberg D  Lis JT 《Science (New York, N.Y.)》2003,301(5636):1094-1096

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Formation of a one-dimensional array of oxygen in a microporous metal-organic solid     

Kitaura R  Kitagawa S  Kubota Y  Kobayashi TC  Kindo K  Mita Y  Matsuo A  Kobayashi M  Chang HC  Ozawa TC  Suzuki M  Sakata M  Takata M 《Science (New York, N.Y.)》2002,298(5602):2358-2361

We report the direct observation of dioxygen molecules physisorbed in the nanochannels of a microporous copper coordination polymer by the MEM (maximum entropy method)/Rietveld method, using in situ high-resolution synchrotron x-ray powder diffraction measurements. The obtained MEM electron density revealed that van der Waals dimers of physisorbed O2 locate in the middle of nanochannels and form a one-dimensional ladder structure aligned to the host channel structure. The observed O-O stretching Raman band and magnetic susceptibilities are characteristic of the confined O2 molecules in one-dimensional nanochannels of CPL-1 (coordination polymer 1 with pillared layer structure).  相似文献   

Simultaneous inhibition and redistribution of spontaneous light emission in photonic crystals     

Fujita M  Takahashi S  Tanaka Y  Asano T  Noda S 《Science (New York, N.Y.)》2005,308(5726):1296-1298

Inhibiting spontaneous light emission and redistributing the energy into useful forms are desirable objectives for advances in various fields, including photonics, illuminations, displays, solar cells, and even quantum-information systems. We demonstrate both the "inhibition" and "redistribution" of spontaneous light emission by using two-dimensional (2D) photonic crystals, in which the refractive index is changed two-dimensionally. The overall spontaneous emission rate is found to be reduced by a factor of 5 as a result of the 2D photonic bandgap effect. Simultaneously, the light energy is redistributed from the 2D plane to the direction normal to the photonic crystal.  相似文献   

Control of light emission by 3D photonic crystals     

Ogawa S  Imada M  Yoshimoto S  Okano M  Noda S 《Science (New York, N.Y.)》2004,305(5681):227-229

Three-dimensional (3D) photonic crystals containing artificial point defects have been fabricated to emit light at optical communications wavelengths. They were constructed by stacking 0.7-micrometer-period gallium arsenide striped layers, resulting in a 3D "woodpile" photonic crystal. Indium-gallium arsenide-phosphide quantum-well layers emitting at a wavelength of 1.55 micrometers were incorporated in the center of the crystal. Samples having up to nine stacked layers were constructed, and artificial point-defect cavities of different sizes were formed in the light-emitting layer. Light emission was suppressed in the photonic crystal regions, whereas cavity modes were successfully observed at the point defects and were size dependent.  相似文献   

Induction of 12-chromosome plants from anther culture in a tuberousSolanum     

Yukio Irikura  Susumu Sakaguchi 《Potato Research》1972,15(2):170-173

Summary Haploid plants (2n=12) were produced by anther culture from the tuber-bearing wild speciesS. verrucosum.  相似文献   

Interactions between predatory sea stars (Asterias amurensis and Distolasterias nipon) and Japanese scallops (Mizuhopecten yessoensis) and implications for scallop seeding in mariculture     

Koji Miyoshi  Yasuhiro Kuwahara  Susumu Chiba 《Aquaculture Research》2019,50(9):2419-2428

Sea stars are a key group of species in benthic marine ecosystems and represent the primary cause of mortality for cultured scallops. In the mariculture grounds of Japanese scallops (Mizuhopecten yessoensis) in north‐eastern Japan, two sea star species, Asterias amurensis (AA) and Distolasterias nipon (DN), are serious predators. However, the predatory impact of these sea stars on scallops remains unquantified, with limited information being available on the biological characteristics of DN. We compared the predatory impact of both sea star species by evaluating their predatory behaviour (i.e. probability of predation and number of captured scallops) on scallops in laboratory experiments. Both sea star species preferred smaller scallops over large ones, with the probability of predation and the number of scallops being preyed on increasing with increasing water temperature. However, DN had a greater predation impact than AA. For instance, the probability of predation by DN was higher, with more scallops being consumed. In particular, compared to AA, DN continuously captured small scallops and fed on larger scallops. Furthermore, the predatory impact of both sea star species (particularly DN) on small scallops peaked at high temperatures. In conclusion, our results present information that could help improve the survival rate of seeded scallops in mariculture systems.  相似文献   

Identification of chloroplast DNA haplotypes ofAbies firma andA. homolepis using a polymerase chain reaction with species-specific primers     

Keiya Isoda  Susumu Shiraishi 《Journal of Forest Research》1999,4(4):291-294

DNA sequences of the chloroplast spacer region between thetrnP andtrnW genes (234 bps) were determined for two Japanese fir species,Abies firma Sieb. et Zucc. andA. homolepis Sieb. et Zucc., using four individuals from each species. No intraspecific variation was found in either species, but interspecific sequence polymorphism was detected between the two species. The interspecific variation was three nucleotide changes, from the 148th to 150th nucleotide position. These three nucleotides were TAC inA. firma and GTA inA. homolepis, which were inverted. In order to identify the cpDNA haplotypes between the two species, this inversion polymorphism was utilized to develop a new marker. Species-specific primers were designed so that the 3′ ends of the primers would anneal to the mutation site, in order for the two haplotypes to be easily identified by a polymerase chain reaction (PCR).  相似文献   

Monitoring genetic stability inQuercus serrata Thunb. somatic embryogenesis using RAPD markers     

Ramesh C. Thakur  Susumu Goto  Katsuaki Ishii  S. Mohan Jain 《Journal of Forest Research》1999,4(2):157-160

Genetic stability of propagules regeneratedvia somatic embryogenesis is of paramount importance for its application to clonal forestry. Random amplified polymorphic DNA (RAPD) markers were used to determine the genetic stability in somatic embryogenesis ofQuercus serrata Thunb. (Japanese white oak). Forty samples from an embryogenic line, consisting of regenerated plantlets, somatic embryos, and embryogenic calli, were examined using 54 decanucleotide primers. A total of 6520 clear reproducible bands obtained from these studies exhibited no aberration in RAPD banding pattern among the tested samples. Our results show that somaclonal variation is absent in our plant propagation system. The genetic stability is discussed in terms of the origin of somatic embryos.  相似文献   

Selection of ABC genes for candidate genes of morphological changes in hydrangea floral organs induced by phytoplasma infection     

Yoshikuni Kitamura  Munetaka Hosokawa  Tatsuya Uemachi  Susumu Yazawa 《Scientia Horticulturae》2009,122(4):603-609

The mechanism underlying the green colouration of floral organs in phytoplasma-infected hydrangeas was studied. Elucidation of morphological changes of floral organs induced by phytoplasma infection and a comparison of the expression level of genes related to floral organ morphogenesis between phytoplasma-infected and non-infected hydrangea plants was conducted. Sixteen hydrangea (Hydrangea spp.) cultivars were used to study structural changes in floral organs induced by Japanese Hydrangea Phyllody (JHP) phytoplasma infection. The homeotic conversion of sepals to leaves was observed in different number of florets between cultivars, and was observed in 75.8–100% of the decorative florets and 2.7–67.3% of the non-decorative florets of JHP phytoplasma-infected inflorescences. The homeotic conversion of carpels to leaves was observed in 1.2–17.9% of the decorative florets and 0.1–18.9% of the non-decorative florets of infected inflorescences. The expression levels of hydrangea orthologues of class A, B and C genes were suppressed in the infected inflorescences during the developmental stage in which no morphological differences in the internal structure of floral organs have been observed. The contribution of this suppression to homeotic conversion of sepals and carpels to leaves was suggested.  相似文献