No abstract

The influence of carbon sources on bacterial community structure in the gut of the wood-feeding higher termite Nasutitermes takasagoensis was investigated. 16S rRNA gene sequencing and terminal-restriction fragment length polymorphism (T-RFLP) analyses revealed that the bacterial community structure changed markedly depending on feed components at the phylum level. Spirochaetes was predominant in the clone libraries from wood- and wood powder-fed termites, whereas Bacteroidetes was the largest group in the libraries from xylan-, cellobiose-, and glucose-fed termites, and Firmicutes was predominant in the library from xylose-fed termites. In addition, clones belonging to the phylum Termite Group I (TG1) were found in the library from xylose-fed termites. Our results indicate that the symbiotic relationship between termite and gut microorganisms is not very strong or stable over a short time, and that termite gut microbial community structures vary depending on components of the feeds.

L‐amino acid oxidases (LAAOs) with broad substrate specificity can be used in the deracemization of D,L‐amino acids (D,L‐AAs) to their D‐enantiomers. Hyper‐thermostable LAAO (HTAncLAAO) was designed through a combination of manual sequence data mining and ancestral sequence reconstruction. Soluble expression of HTAncLAAO (>50 mg/L) can be achieved using an E. coli system. HTAncLAAO, which recognizes seven L‐AAs as substrates, exhibits extremely high thermal stability and long‐term stability; the t1/2 value was 95 °C and <5% activity loss after incubation of the enzyme at 30 °C for 1 week. Deracemization could be achieved at 40 °C with a small amount of enzymes compared to previously reported LAAOs. A total of 0.4 mg (2 U) of HTAncLAAO is enough to deracemize three D,L‐AAs at a preparative scale with high enantiomeric excess (>99 % ee, D‐enantiomer). These results suggest that HTAncLAAO is an excellent biocatalyst to perform this deracemization.

In August 2015, the CALorimetric Electron Telescope (CALET), designed for long exposure observations of high energy cosmic rays, docked with the International Space Station (ISS) and shortly thereafter began to collect data. CALET will measure the cosmic ray electron spectrum over the energy range of 1 GeV to 20 TeV with a very high resolution of 2% above 100 GeV, based on a dedicated instrument incorporating an exceptionally thick 30 radiation-length calorimeter with both total absorption and imaging (TASC and IMC) units. Each TASC readout channel must be carefully calibrated over the extremely wide dynamic range of CALET that spans six orders of magnitude in order to obtain a degree of calibration accuracy matching the resolution of energy measurements. These calibrations consist of calculating the conversion factors between ADC units and energy deposits, ensuring linearity over each gain range, and providing a seamless transition between neighboring gain ranges. This paper describes these calibration methods in detail, along with the resulting data and associated accuracies. The results presented in this paper show that a sufficient accuracy was achieved for the calibrations of each channel in order to obtain a suitable resolution over the entire dynamic range of the electron spectrum measurement