Total Synthesis of (-)-Sigillin A: A Polychlorinated and Polyoxygenated Natural Product

The total synthesis of (−)-sigillin A, a highly chlorinated and oxygenated octahydroisocoumarin, is described herein. A hexahydroisocoumarin skeleton was constructed from (R)-4-(trichloromethyl)oxetan-2-one in seven steps. Its unique manganese oxidation provided an enone as the key intermediate of sigillin A. Stereoselective installation of two hydroxy groups and formation of gem-dichloroalkene from the corresponding ketone led to the total synthesis of (−)-sigillin A in a total of 16 steps

Increased tolerance to photooxidative stress by overexpression of mitochondrial superoxide dismutase in transgenic tobacco

76-80Under abiotic stress conditions, plants suffer from oxidative damage caused by increased generation of reactive oxygen species (ROS). Although chloroplasts are the main source of ROS generation in plant cells, changes in ROS level in mitochondria affect plant stress response. In this study, we investigated whether overexpression of mitochondrial manganese superoxide dismutase (Mn-SOD) can enhance tolerance to photooxidative stress. We produced transgenic tobacco plants overexpressing rice Mn-SOD under the control of cauliflower mosaic virus 35S promoter, and assessed the stress tolerance of those plants. The transgenic lines showed higher total SOD activity by 2.8 to 5.2 fold than wild type plants. Chlorophyll fluorescence measurement revealed that the stress-induced inhibition of photosystem II was alleviated under high light, chilling and heat stresses in the transgenic lines. This result indicates that the Mn-SOD contributes to the defense against photooxidative damages in chloroplasts under these stress conditions

The Japanese space gravitational wave antenna; DECIGO

DECi-hertz Interferometer Gravitational wave Observatory (DECIGO) is the future Japanese space gravitational wave antenna. DECIGO is expected to open a new window of observation for gravitational wave astronomy especially between 0.1 Hz and 10 Hz, revealing various mysteries of the universe such as dark energy, formation mechanism of supermassive black holes, and inflation of the universe. The pre-conceptual design of DECIGO consists of three drag-free spacecraft, whose relative displacements are measured by a differential Fabry– Perot Michelson interferometer. We plan to launch two missions, DECIGO pathfinder and pre- DECIGO first and finally DECIGO in 2024

DECIGO pathfinder

DECIGO pathfinder (DPF) is a milestone satellite mission for DECIGO (DECi-hertz Interferometer Gravitational wave Observatory) which is a future space gravitational wave antenna. DECIGO is expected to provide us fruitful insights into the universe, in particular about dark energy, a formation mechanism of supermassive black holes, and the inflation of the universe. Since DECIGO will be an extremely large mission which will formed by three drag-free spacecraft with 1000m separation, it is significant to gain the technical feasibility of DECIGO before its planned launch in 2024. Thus, we are planning to launch two milestone missions: DPF and pre-DECIGO. The conceptual design and current status of the first milestone mission, DPF, are reviewed in this article

Onset and development of cannibalistic and schooling behavior in the early life stages of Pacific bluefin tuna Thunnus orientalis

Behavioral development was observed in the early life stages of Pacific bluefin tuna in order to provide fundamental information for improving seedling production techniques. Behavioral observations to quantify swimming, schooling and cannibalistic behavior were made at different developmental stages: pre-flexion (5 days after hatching, DAH), flexion (12 DAH), post-flexion (14 DAH) and juvenile (20 DAH). Video recordings of either observation containers or the rearing tank were made to observe swimming and schooling behavior, respectively. Cannibalistic behavior was estimated by frequency of chase behavior. Swimming speed maintained constant values from 6 DAH (9.2 ± 6.0 mm/s, pre-flexion stage) to 20 DAH (22.4 ± 9.0 mm/s, beginning of juvenile stage) and increased rapidly thereafter to 29 DAH (85.2 ± 32.5 mm/s). Schooling behavior was first observed on 25 DAH juveniles (SL 23.5 ± 5.0 mm). Chase behavior was first observed at 14 DAH (standard length, SL 6.1 ± 0.6 mm, transition at flexion to post-flexion stage) and increased thereafter. We propose that a practical developmental stage for size grading to reduce the mortality by cannibalism should be between post-flexion and early juvenile (SL 6-23 mm), when the cannibalistic behavior onsets and swimming speed are relatively low

Current status of space gravitational wave antenna DECIGO and B-DECIGO

Deci-hertz Interferometer Gravitational Wave Observatory (DECIGO) is the future Japanese space mission with a frequency band of 0.1 Hz to 10 Hz. DECIGO aims at the detection of primordial gravitational waves, which could be produced during the inflationary period right after the birth of the universe. There are many other scientific objectives of DECIGO, including the direct measurement of the acceleration of the expansion of the universe, and reliable and accurate predictions of the timing and locations of neutron star/black hole binary coalescences. DECIGO consists of four clusters of observatories placed in the heliocentric orbit. Each cluster consists of three spacecraft, which form three Fabry-Perot Michelson interferometers with an arm length of 1,000 km. Three clusters of DECIGO will be placed far from each other, and the fourth cluster will be placed in the same position as one of the three clusters to obtain the correlation signals for the detection of the primordial gravitational waves. We plan to launch B-DECIGO, which is a scientific pathfinder of DECIGO, before DECIGO in the 2030s to demonstrate the technologies required for DECIGO, as well as to obtain fruitful scientific results to further expand the multi-messenger astronomy.Comment: 10 pages, 3 figure