Characterization of highly efficient heavy-ion mutagenesis in Arabidopsis thaliana

<p>Abstract</p> <p>Background</p> <p>Heavy-ion mutagenesis is recognised as a powerful technology to generate new mutants, especially in higher plants. Heavy-ion beams show high linear energy transfer (LET) and thus more effectively induce DNA double-strand breaks than other mutagenic techniques. Previously, we determined the most effective heavy-ion LET (LET_max: 30.0 keV μm^-1) for <it>Arabidopsis </it>mutagenesis by analysing the effect of LET on mutation induction. However, the molecular structure of mutated DNA induced by heavy ions with LET_maxremains unclear. Knowledge of the structure of mutated DNA will contribute to the effective exploitation of heavy-ion beam mutagenesis.</p> <p>Results</p> <p>Dry <it>Arabidopsis thaliana </it>seeds were irradiated with carbon (C) ions with LET_maxat a dose of 400 Gy and with LET of 22.5 keV μm^-1at doses of 250 Gy or 450 Gy. The effects on mutation frequency and alteration of DNA structure were compared. To characterise the structure of mutated DNA, we screened the well-characterised mutants <it>elongated hypocotyls </it>(<it>hy</it>) and <it>glabrous </it>(<it>gl</it>) and identified mutated DNA among the resulting mutants by high-resolution melting curve, PCR and sequencing analyses. The mutation frequency induced by C ions with LET_maxwas two-fold higher than that with 22.5 keV μm^-1and similar to the mutation frequency previously induced by ethyl methane sulfonate. We identified the structure of 22 mutated DNAs. Over 80% of the mutations caused by C ions with both LETs were base substitutions or deletions/insertions of less than 100 bp. The other mutations involved large rearrangements.</p> <p>Conclusions</p> <p>The C ions with LET_maxshowed high mutation efficiency and predominantly induced base substitutions or small deletions/insertions, most of which were null mutations. These small alterations can be determined by single-nucleotide polymorphism (SNP) detection systems. Therefore, C ions with LET_maxmight be useful as a highly efficient reverse genetic system in conjunction with SNP detection systems, and will be beneficial for forward genetics and plant breeding.</p

Selection of early maturing and high yielding mutants of Toraja Local Red Rice Grown from M2-M3 Population after Ion Beam Irradiation

This study aims to obtain the genotype of local Toraja red rice M2 mutants that have the potential to be developed into early maturing varieties and have high yields. Research carried out with a mass selection method consisting of two irradiation treatments, namely: (1) irradiation with a Carbon ion dose of 150 Gy (PL-C); (2) irradiation with Argon ion dose of 10 Gy (PL-A) and control as a comparison. Selected strains of M2 seed population were planted in experimental strains plus 2 strains as control, each row had 50 plants. Selection is done in two stages. The first stage, the selection is based on the criteria of plant growth components, to select rice plants that have early-middle age characters, dwarf-semi-dwarf, and many tillers. The second stage, selected strains from the scoring method were then grouped based on the degree of similarity with the cluster analysis method. Irradiation with ion beams produces mutants with shorter harvest times than their parents, with the harvest time 16-17 days or 10% shorter compared to their parents. This study produced 10 selected strains, 5 strains of carbon ion and 5 strains of argon ion irradiation treatment, and formed 5 groups with a 90% similarity coefficient

ゼツアツ コウトウ ウンドウ ケイソク システム ニ ヨル パーキンソンビョウ カンジャ ノ エンゲ ドウタイ ヒョウカ

The different forms of flowers in a species have attracted the attention of many evolutionary biologists, including Charles Darwin. In Fagopyrum esculentum (common buckwheat), the occurrence of dimorphic flowers, namely short-styled and long-styled flowers, is associated with a type of self-incompatibility (SI) called heteromorphic SI. The floral morphology and intra-morph incompatibility are both determined by a single genetic locus named the S-locus. Plants with short-styled flowers are heterozygous (S/s) and plants with long-styled flowers are homozygous recessive (s/s) at the S-locus. Despite recent progress in our understanding of the molecular basis of flower development and plant SI systems, the molecular mechanisms underlying heteromorphic SI remain unresolved. By examining differentially expressed genes from the styles of the two floral morphs, we identified a gene that is expressed only in short-styled plants. The novel gene identified was completely linked to the S-locus in a linkage analysis of 1,373 plants and had homology to EARLY FLOWERING 3. We named this gene S-LOCUS EARLY FLOWERING 3 (S-ELF3). In an ion-beam-induced mutant that harbored a deletion in the genomic region spanning S-ELF3, a phenotype shift from short-styled flowers to long-styled flowers was observed. Furthermore, S-ELF3 was present in the genome of short-styled plants and absent from that of long-styled plants both in world-wide landraces of buckwheat and in two distantly related Fagopyrum species that exhibit heteromorphic SI. Moreover, independent disruptions of S-ELF3 were detected in a recently emerged self-compatible Fagopyrum species and a self-compatible line of buckwheat. The nonessential role of S-ELF3 in the survival of individuals and the prolonged evolutionary presence only in the genomes of short-styled plants exhibiting heteromorphic SI suggests that S-ELF3 is a suitable candidate gene for the control of the short-styled phenotype of buckwheat plants

給食管理実習中の手拭の細菌汚染(自然科学)

集団給食作業中に使用された手拭の細菌汚染の実体を明らかにすることを目的として研究した。1)給食実習の調理に使用した手拭には,一般生菌10^7,大腸菌群10^4,ブドウ球菌10^4程度の細菌が汚染していた。2)手拭を汚染している細菌群は,水道水,中性洗剤の使用による洗浄によっても容易に除去されず,一般生菌,大腸菌群,ブドウ球菌など多数が残存した。3)手拭は洗浄後できるだけ速やかに乾燥しなければ,汚染細菌が著しく増殖するので,調理に使用した手拭は,洗浄,加熱殺菌,乾燥などの処理が衛生上必要である。4)手拭を汚染していた大腸菌群の中には,Escherichia coli, Citrobacter freundii, Klebsiella pneumonia, Enterobacter cloacaeなどに属する菌株が含まれ,特にEscherichia coliに属するものが最も多く分離され,ふん便からの汚染の可能性が示唆された。5)分離した34菌株のブドウ球菌は,7.5%NaCl培地中ですべてよく増殖し,10%NaCl培地では70%が増殖し,15%NaCl培地ではすべて増殖しなかった。また分離菌株中28菌株(82%)がmannitを分解した

Psychological Effects of Hands-On Training Using Public Transportation among Inpatients with Physical Disabilities: Analysis of the Self-Efficacy and Perception of Occupational Enablement Using a Multimethod Design

Introduction. This study is aimed at understanding how practicing the use of public transportation can affect the self-efficacy and perceptions of occupational enablement among patients with physical disabilities in a recovery rehabilitation hospital. Method. We recruited 21 inpatients with physical disabilities caused by stroke or orthopedic diseases from a recovery rehabilitation hospital in Japan and used a multimethod design including an intervention study and a follow-up survey. The intervention study utilized a before-after trial and provided hands-on training in the use of public transportation as the intervention. How self-efficacy and perceptions of occupational enablement changed before and after the intervention was measured using the visual analog scale (VAS). The follow-up survey was conducted to investigate whether patients used public transportation postdischarge. Results. Only differences in the VAS scores regarding self-efficacy were significant between before and after the hands-on training in the use of public transportation, whereas differences regarding the perceptions of occupation enablement were not. Self-efficacy after the intervention was higher than that before the intervention. In the follow-up survey, both VAS scores of the psychological factors were significantly higher in the group that used public transportation postdischarge than in the group that did not. Conclusion. Providing hands-on training in the use of public transportation for inpatients with physical disabilities increased their self-efficacy, indicating that psychological factors should be evaluated to predict their occupational skill improvement and to verify the outcomes of an occupational therapeutic intervention

Gamma Knife Irradiation of Injured Sciatic Nerve Induces Histological and Behavioral Improvement in the Rat Neuropathic Pain Model

<div><p>We examined the effects of gamma knife (GK) irradiation on injured nerves using a rat partial sciatic nerve ligation (PSL) model. GK irradiation was performed at one week after ligation and nerve preparations were made three weeks after ligation. GK irradiation is known to induce immune responses such as glial cell activation in the central nervous system. Thus, we determined the effects of GK irradiation on macrophages using immunoblot and histochemical analyses. Expression of Iba-1 protein, a macrophage marker, was further increased in GK-treated injured nerves as compared with non-irradiated injured nerves. Immunohistochemical study of Iba-1 in GK-irradiated injured sciatic nerves demonstrated Iba-1 positive macrophage accumulation to be enhanced in areas distal to the ligation point. In the same area, myelin debris was also more efficiently removed by GK-irradiation. Myelin debris clearance by macrophages is thought to contribute to a permissive environment for axon growth. In the immunoblot study, GK irradiation significantly increased expressions of βIII-tubulin protein and myelin protein zero, which are markers of axon regeneration and re-myelination, respectively. Toluidine blue staining revealed the re-myelinated fiber diameter to be larger at proximal sites and that the re-myelinated fiber number was increased at distal sites in GK-irradiated injured nerves as compared with non-irradiated injured nerves. These results suggest that GK irradiation of injured nerves facilitates regeneration and re-myelination. In a behavior study, early alleviation of allodynia was observed with GK irradiation in PSL rats. When GK-induced alleviation of allodynia was initially detected, the expression of glial cell line-derived neurotrophic factor (GDNF), a potent analgesic factor, was significantly increased by GK irradiation. These results suggested that GK irradiation alleviates allodynia via increased GDNF. This study provides novel evidence that GK irradiation of injured peripheral nerves may have beneficial effects.</p></div