CHOICE OF COATINGS FOR THE OPTICAL ELEMENTS IN THE IRRADIATION SYSTEM OF VACUUM-ULTRAVIOLET RADIATION ABOVE 50 nm

The spectral throughput of a vacuum-ultraviolet irradiation system at the SOR-RING facility was examined with various combinations of aluminum-and gold-coated optical elements in a 2.2-m modified Wadsworth monochromator. We found that the optimum was a combination of an aluminum-coated collimating mirror, concave grating, and plane deflecting mirror, and a combination of a gold-coated collimating mirror, concave grating and an aluminum-coated plane deflecting mirror in the wavelength regions 190-110 nm and 110-50 nm, respectively.     

LETHAL AND MUTAGENIC ACTION OF VACUUM-AND FAR-ULTRAVIOLET RADIATIONS ON DRY X174 PHAGE

Killing and mutation of dry X174 phages (amber mutant) were investigated with vacuum-UV (130, 150 and 190 nm) and far-UV (254 nm) radiations. The sensitivity to killing was greatest at 130 nm; the sensitivity (in terms of energy fluence) at 130 nm was about 17 times higher than that at 150 nm. The reversion frequency of amber mutants to pseudo-wild type at 190 nm was lower than at 254 nm. Comparison of the induction rate of revertants per survivor showed that mutagenicity after 130 nm radiation, which may raise the ionization process, and after X-rays was similar.     

A survey of metabolic changes in potato leaves by NMR‐based metabolic profiling in relation to resistance to late blight disease under field conditions

Non‐targeted nuclear magnetic resonance (NMR)‐based metabolic profiling was applied to potato leaves to survey metabolic changes associated with late blight resistance under field conditions. Potato plants were grown in an experimental field, and the compound leaves with no visible symptoms were collected from 20 cultivars/lines at two sampling time points: (i) the time of initial presentation of symptoms in susceptible cultivars and (ii) 12 days before this initiation. ¹H NMR spectra of the foliar metabolites soluble in deuterium oxide‐ or methanol‐d₄‐based buffers were measured and used for multivariate analysis. Principal component analysis for six cultivars at symptom initiation showed a class separation corresponding to their levels of late blight resistance. This separation was primarily explained by higher levels of malic acid, methanol, and rutin and a lower level of sucrose in the resistant cultivars than in the susceptible ones. Partial least squares regression revealed that the levels of these metabolites were strongly associated with the disease severity measured in this study under field conditions. These associations were observed only for the leaves harvested at the symptom initiation stage, but not for those collected 12 days beforehand. Subsequently, a simple, alternative enzymatic assay for l ‐malic acid was used to estimate late blight resistance, as a model for applying the potential metabolic marker obtained. This study demonstrated the potential of metabolomics for field‐grown plants in combination with targeted methods for quantifying marker levels, moving towards marker‐assisted screening of new cultivars with durable late blight resistance. Copyright © 2016 John Wiley & Sons, Ltd.     

In situ observation of cell-detachment process initiated by femtosecond laser-induced stress wave

When a stress wave generated by focusing a femtosecond laser is loaded on an animal cell adhered on a substrate, the cell is detached from the substrate. There are two possible mechanisms for the cell detachment: (a) The cell is detached from a scaffold coated on a glass plate, and (b) the cell is detached from the glass plate with the scaffold. In this work, we have studied the cell-detachment mechanism by visualizing the scaffold with a fluorescence probe of quantum dots. When the cell was detached from the substrate, fluorescence from the scaffold simultaneously disappeared from the glass plate, although the scaffold was not irradiated by the laser. This indicates that detachment due to the stress wave is attributed to mechanism (a). On the other hand, when the cell was detached from the substrate by a trypsin treatment, the fluorescence from the scaffold remained, suggesting mechanism (b). By comparing both results, it is considered that physiological damage of the cell membrane during the detachment process by femtosecond laser-induced stress wave is less than that due to the trypsin treatment.     

Bioactive saponins and glycosides. XXVIII. New triterpene saponins, foliatheasaponins I, II, III, IV, and V, from Tencha (the leaves of Camellia sinensis)

New triterpene saponins, foliatheasaponins I-V, were isolated from the methanolic extract of Tencha [the leaves of Camellia sinensis (L.) O. KUNTZE (Theaceae)]. The chemical structures of these new saponins were elucidated on the basis of chemical and physicochemical evidence. Among the new saponins, foliatheasaponins II and III, were found to inhibit release of beta-hexosaminidase, as a marker of antigen-induced degranulation, in RBL-2H3 cells.     

Primary cultures of chick osteocytes retain functional gap junctions between osteocytes and between osteocytes and osteoblasts.

The inaccessibility of osteocytes due to their embedment in the calcified bone matrix in vivo has precluded direct demonstration that osteocytes use gap junctions as a means of intercellular communication. In this article, we report successfully isolating primary cultures of osteocytes from chick calvaria, and, using anti-connexin 43 immunocytochemistry, demonstrate gap junction distribution to be comparable to that found in vivo. Next, we demonstrate the functionality of the gap junctions by (1) dye coupling studies that showed the spread of microinjected Lucifer Yellow from osteoblast to osteocyte and between adjacent osteocytes and (2) analysis of fluorescence replacement after photobleaching (FRAP), in which photobleaching of cells loaded with a membrane-permeable dye resulted in rapid recovery of fluorescence into the photobleached osteocyte, within 5 min postbleaching. This FRAP effect did not occur when cells were treated with a gap junction blocker (18alpha-glycyrrhetinic acid), but replacement of fluorescence into the photobleached cell resumed when it was removed. These studies demonstrate that gap junctions are responsible for intercellular communication between adjacent osteocytes and between osteoblasts and osteocytes. This role is consistent with the ability of osteocytes to respond to and transmit signals over long distances while embedded in a calcified matrix.     

Local stimulation of cultured myocyte cells by femtosecond laser-induced stress wave

When an 800 nm femtosecond laser is tightly focused into cell culture medium a stress wave is generated at the laser focal point. Since the stress wave localizes in a few tens of μm, it is possible to locally stimulate single cells in vitro. In this work, several kinds of cultured mammalian cells, HeLa, PC12, P19CL6, and C2C12, were stimulated by the stress wave and the cell growth after the stress loading with the laser irradiation was investigated. In comparison with the control conditions, cell growth after the laser irradiation was enhanced for the cells of C2C12 and P19CL6, which can differentiate into myocytes, and suppressed for PC12 and HeLa cell lines. These results suggest a possibility of cell growth enhancement due to myogenic cells response to the femtosecond laser-induced stress.