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Context. Proper motion observations of masers can provide information on dynamic motions on scales of a few milliarcseconds per year (mas yr-1) at radii of 100-1000 au scales from central young stellar objects (YSOs). Aims. The 6.7 GHz methanol masers are one of the best probes for investigations of the dynamics of high-mass YSOs, and in particular for tracing the rotating disk. We have measured the internal proper motions of the 6.7 GHz methanol masers associated with Cepheus A (Cep A) HW2 using Very Long Baseline Interferometery (VLBI) observations. Methods. We conducted three epochs of VLBI monitoring observations of the 6.7 GHz methanol masers in Cep A-HW2 with the Japanese VLBI Network (JVN) over the period 2006-2008. In 2006, we were able to use phase-referencing to measure the absolute coordinates of the maser emission with an accuracy of a few milliarcseconds. We compared the maser distribution with other molecular line observations that trace the rotating disk. Results. We measured the internal proper motions for 29 methanol maser spots, of which 19 were identified at all three epochs and the remaining ten at only two epochs. The magnitude of proper motions ranged from 0.2 to 7.4 km s-1, with an average of 3.1 km s-1. Although there are large uncertainties in the observed internal proper motions of the methanol maser spots in Cep A, they are well fitted by a disk that includes both rotation and infall velocity components. The derived rotation and infall velocities at the disk radius of 680 au are 0.5 ± 0.7 and 1.8 ± 0.7 km s-1, respectively. Conclusions. Assuming that the modeled disk motion accurately represents the accretion disk around the Cep A-HW2 high-mass YSO, we estimated the mass infall rate to be 3×10-4 n8 M☉ yr-1 (n8 is the gas volume density in units of 108 cm-3). The combination of the estimated mass infall rate and the magnitude of the fitted infall velocity suggests that Cep A-HW2 is at an evolutionary phase of active gas accretion from the disk onto the central high-mass YSO. The infall momentum rate is estimated to be 5 × 10-4 n8 M☉ yr-1 km s-1, which is larger than the estimated stellar radiation pressure of the HW2 object, supporting the hypothesis that this object is in an active gas accretion phase. [ABSTRACT FROM AUTHOR]

Abstract  Nitrogen content and δ15N (nitrogen stable isotope ratio) were measured in different parts of the sporophyte of Undaria pinnatifida (Harvey) Suringar from two bays in the northeastern Japan. There were clear differences between the thalli collected in winter and in summer: high nitrogen content and low average δ15N were observed for the thalli collected in winter, while the opposite pattern was found for the thalli from summer. In addition, the pattern of internal δ15N distribution in the thallus changed with season. It is possible that the cause for these seasonal differences in the algae was the seasonal change in environmental conditions, because in winter water is normally rich in nitrogen, while in summer it is poor. U. pinnatifida sporophyte may be useful as an indicator of nitrogen sources in coastal waters, but consideration must be given to the effect of isotope fractionation on δ15N of the plant, especially in winter. Potential may exist for the use of different parts of the thallus to indicate nitrogen sources at different periods, but more investigation is necessary to accomplish this. [ABSTRACT FROM AUTHOR]

Abstract  The photosynthetic and respiratory responses to irradiance, salinity and temperature of the red alga, Gracilaria vermiculophylla, collected from Kumamoto, Shizuoka and Iwate in Japan were studied using an electronic Dissolved Oxygen sensor. The parameters derived from the photosynthesis versus irradiance relationship indicated the potential to acclimate to broad irradiance variations in all of the populations of G. vermiculophylla collected from these three sites. In addition, the light-saturated photosynthesis rate (P max) and the dark respiration rate of all populations increased with increasing temperature up to 20–30°C, while the P max decreased at 35°C. All populations also showed a broad variation of photosynthetic responses to salinity changes in the range from 10 to 30 psu. On the other hand, the population from Iwate showed high photosynthetic efficiency, especially in the temperature range of 5–10°C, and showed low values of saturation irradiance compared to the populations from Shizuoka and Kumamoto. These results suggest that there is greater potential to acclimate to low irradiance and low temperature in the population from Iwate compared to those from the Shizuoka and Kumamoto populations. However, the P max of the populations from Iwate and Shizuoka was reached at 20°C and 25°C, respectively, while the Kumamoto population reached P max at 30°C. This implies that the latter population has greater potential to tolerate higher temperatures than the former. Such characteristics in photosynthesis and respiration of G. vermiculophylla collected from the three locations probably indicate an acclimation to prevailing environmental conditions in their respective habitats. [ABSTRACT FROM AUTHOR]

Abstract  The photosynthetic and respiratory responses of Gracilaria salicornia in the subtropical waters of Japan (in Okinawa) and in the tropical waters of Thailand (in Rayong and Phuket Provinces), were studied under various conditions of irradiance, salinity and temperature. This alga showed adaptability in its photosynthetic and respiratory responses to oceanic salinity as well as to subtropical to tropical temperature. Significant differences in the photosynthetic and respiratory rates among the G. salicornia populations collected from the above sites were observed. The Phuket population showed adaptability to high irradiance and temperature, characteristic of its natural sun-exposed environment, as it exhibited the highest I k and I c, and lowest α and higher P max at 30–35�C. On the other hand, the Okinawa population demonstrated adaptability to low submarine irradiance as it had a lower I k and I c than either population from Thailand. Its P max at 20–25�C was also higher than that of the Phuket population. The Rayong population, however, showed the highest P max, Rd, α, I k and I c, suggesting its adaptability to both sun and shade light conditions in its natural environment. [ABSTRACT FROM AUTHOR]

The β chain, a component of the high-affinity receptor for IgE (FcεRI), plays an important role in IgE-mediated allergic reaction. The β chain accelerates the function of FcεRI by amplification of its surface expression and of signal transduction in effector cells such as mast cells and basophils. Two regulatory regions, +60/+66 and +70/+76, for the human β chain gene that are required for the cell-type-specific transcriptional activation were identified by transient reporter assay. Electrophoretic mobility shift assay demonstrated that Oct-1 binds both the regions, among which the +70/+76 Oct-1 motif was critical for the transactivation of the β promoter responsive to Oct-1 overexpression. Regulation of β chain gene expression is discussed. [ABSTRACT FROM AUTHOR]

Mouse androgenetic and parthenogenetic embryos, which have two sets of paternal and maternal genomes, respectively, are lethal until Day 9.5 of pregnancy, because the growth of the extraembryonic tissues including placenta is inadequate. These results suggest that both parental genomes are involved in placental development. However, the reason for placental deficiency in androgenetic and parthenogenetic embryos has been unclear. Trophoblast stem (TS) cells, which have the ability to differentiate into trophoblast lineage, have been used to elucidate the mechanism of differentiation and gene function in the development of the placenta. In this study, to characterize trophoblast lineage in androgenetic and parthenogenetic embryos, we examined TS cells from these embryos, and assessed their ability to differentiate into trophoblast lineage. The ovulated MII oocytes from B6D2F1 (C57BL/6 DBA2) female mice were used for the uniparental embryo production. In order to produce parthenogenetic embryos, the oocytes were activated in SrCl2 and cytochalasin B. The androgenetic embryos were produced by in vitro fertilization using enucleated oocytes. These uniparental embryos were cultured for 3.5–4.5 days to develop into blastocysts. TS-like cell lines were established from these blastocysts, as described previously (Tanaka et al. 1998 Science 282, 2072–2075). TS-like cells were cultured without feeder cells in conditioned medium containing FGF4 and heparin to maintain the stem cell conditions. The expression of 5 TS cell maker genes (Eomes, CdX2, Fgfr2, Ap2a, and Errb) in TS-like cells was analyzed by RT-PCR and northern blotting. In addition, the localization of CDX2 was detected using immunostaining. To cause their differentiation into giant cells, TS-like cells were cultured for 6 days in TS medium without FGF4 and heparin. The giant cells were detected by the expression of 2 giant cell marker genes, Hand1 and Pl-1. TS cells from fertilized embryos between B6D2F1 male and female mice were also established as controls. Five TS cell marker genes were expressed both in androgenetic TS-like cells (ATS) and in parthenogenetic ones (PTS). The CDX2 gene was localized in the nucleus in both ATS and PTS; however, the number of CDX2-positive cells decreased in PTS. After 6 days of differentiation, Hand1 and Pl-1 were expressed and giant cells were detected in differentiated derivatives in ATS. On the other hand, giant cells were not detected in differentiated derivatives in PTS. These results suggest that parental genomes may regulate the gene expression independently to differentiate into trophoblast lineage. In conclusion, TS-like cells from uniparental embryos are useful tools to aid the understanding of the function of the parental genomes during placental development. [ABSTRACT FROM AUTHOR]