In transposon-tagged lines of Arabidopsis we found two new mutants, cof1-1 and cof1-2 (cuticular defect and organ fusion), that show the phenotype of wilting when grown in soil, organ fusion of ...rosette leaves and infertility. Toluidine blue testing and scanning electron microscopy observation revealed that these mutants had cuticular defects in the stems and adult leaves, but not in cotyledones. Transmission electron microscopy observation revealed thinner cuticle layers in the mutants, and cuticular materials interspersed between the two fused epidermal layers were observed in the mutant rosette leaves. These two mutants had a transposon insertion in the coding regions of WBC11, which was classified as a member of ABC transporter genes in Arabidopsis. WBC11 showed high sequence similarity to CER5 (also called WBC12), which was involved in cuticular lipid export. Gas chromatographic analysis revealed that C29 alkane extracted from the stem surface of cof1 mutants was reduced whereas C29 ketone was accumulated, which was different from the case of cer5 mutants. While cer5 mutants had fairly normal morphology, cof1 mutants had pleiotropic phenotypes so that COF1/WBC11 could have important roles different from those of CER5/WBC12. We also found that C29 alkane was accumulated in the intracellular extract of cof1 mutants, suggesting a function for WBC11 in the direct transport of lipid molecules. Pollen observation showed that mutant pollen grains were irregularly shaped. The function of COF1/WBC11 in lipid transport for the construction of cuticle layers and pollen coats for normal organ formation is discussed.
A fast‐flowing tributary of Recovery ice stream penetrates more than 500 km into the interior of East Antarctica. Recent satellite‐based studies found surface features in the onset area of this ...tributary that indicate a significant subglacial hydraulic system, including four large smooth basins, the typical surface expression of large subglacial lakes, as well as eleven smaller areas over which ice‐sheet surface elevations rapidly changed by discharge/filling of subglacial water. Here we present the first ice‐penetrating radar evidence of subglacial conditions in this area. We identified a distinct ice‐water interface only over a limited area within the boundaries of the investigated large smooth basins, previously hypothesized to be water‐filled lakes. The radar characteristics in some areas are similar to those of a drained lake, indicating that parts of the bed are wet, but not a typical lake. We also find evidence for discrete water bodies outside of the lake boundaries. The lines of evidence indicate that the northern most two Recovery Lakes have recently drained.
N-glycosylation of proteins in the endoplasmic reticulum (ER) has a central role in protein quality control. Here we report that N-glycan serves as a signal for degradation by the ...Skp1-Cullin1-Fbx2-Roc1 (SCFFbx2) ubiquitin ligase complex. The F-box protein Fbx2 (ref. 4) binds specifically to proteins attached to N-linked high-mannose oligosaccharides and subsequently contributes to ubiquitination of N-glycosylated proteins. Pre-integrin β1 is a target of Fbx2; these two proteins interact in the cytosol after inhibition of the proteasome. In addition, expression of the mutant Fbx2ΔF, which lacks the F-box domain that is essential for forming the SCF complex, appreciably blocks degradation of typical substrates of the ER-associated degradation pathway. Our results indicate that SCFFbx2 ubiquitinates N-glycosylated proteins that are translocated from the ER to the cytosol by the quality control mechanism.
We present a deep optical spectrum of TN J0924−2201, the most distant radio galaxy at z = 5.19, obtained with FOCAS on the Subaru Telescope. We successfully detect, for the first time, the C ...ivλ1549 emission line from the narrow-line region. In addition to the emission-line fluxes of Lyα and C iv, we set upper limits on the N v and He ii emissions. We use these line detections and upper limits to constrain the chemical properties of TN J0924−2201. By comparing the observed emission-line flux ratios with photoionization models, we infer that the carbon-to-oxygen relative abundance is already C/O > −0.5 at a cosmic age of ~1.1 Gyr. This lower limit on C/O is higher than the ratio expected at the earliest phases of the galaxy chemical evolution, indicating that TN J0924−2201 has already experienced significant chemical evolution at z = 5.19.
Search for the ultra-rare process, neutrino-less double beta decay, is a powerful tool to test the Majorana nature of neutrinos. Among the potential double beta decay nuclei, 48Ca has the largest ...Q-value, hence we can expect the measurement with least background. On the other hand, due to its low natural abundance, isotope enrichment is essential to achieve the sensitivity in the region of interest (inverted/normal mass hierarchy of neutrinos).We have been developing a laser isotope separation method using a tunable semiconductor laser that can excite only a specific isotope (48Ca). The laser is irradiated perpendicular to the collimated calcium vapor beam. Only 48Ca atoms are separated by deflecting them from the original atomic beam by momentum transfer due to multiple absorption and emission of laser photons. The isotope separation is confirmed by irradiating an ionization laser and time-of-flight measurement.Following the success of the proof-of-principle experiment, we are now developing the mass production system which include efficient generation of atomic beams, frequency-stabilized high-power laser, efficient laser irradiation method, and collection method of deflected isotope beams. In this paper, we report on the status and prospects of these developments.
Ice shelves around Antarctica can provide back stress for outlet glaciers and control ice sheet mass loss. They often contain narrow bands of thin ice termed ice shelf channels. Ice shelf channel ...morphology can be interpreted through surface depressions and exhibits junctions and deflections from flowlines. Using ice flow modeling and radar, we investigate ice shelf channels in the Roi Baudouin Ice Shelf. These are aligned obliquely to the prevailing easterly winds. In the shallow radar stratigraphy, syncline and anticline stacks occur beneath the upwind and downwind side, respectively. The structures are horizontally and vertically coherent, except near an ice shelf channel junction where patterns change structurally with depth. Deeper layers truncate near basal incisions. Using ice flow modeling, we show that the stratigraphy is ∼9 times more sensitive to atmospheric variability than to oceanic variability. This is due to the continual adjustment toward flotation. We propose that syncline‐anticline pairs in the shallow stratigraphy are caused by preferential snow deposition on the windward side and wind erosion at the downwind side. This drives downwind deflection of ice shelf channels of several meters per year. The depth variable structures indicate formation of an ice shelf channel junction by basal melting. We conclude that many ice shelf channels are seeded at the grounding line. Their morphology farther seaward is shaped on different length scales by ice dynamics, the ocean, and the atmosphere. These processes act on finer (subkilometer) scales than are captured by most ice, atmosphere, and ocean models, yet the dynamics of ice shelf channels may have broader implications for ice shelf stability.
Plain Language Summary
Ice flows from Antarctica's interior toward the coast. At the contact point between ice and ocean, the ice becomes afloat and forms fast‐flowing ice shelves. Snowfall continuously accumulates at the ice shelf surface, and at the ice shelf bottom the relatively warm ocean water can melt ice from below. Ice shelves sometimes exhibit a network of surface depressions resembling a river network. At the base, the depressions are accompanied by large incisions termed ice shelf channels. Using radar as a tool for echolocation, we investigate how the shape of this network is formed. We find that snow preferentially collects in the upwind side of the surface depressions. This makes ice shelf channels move to the downwind side. We also find that ice shelf channels can form junctions through localized ocean melting. This is important because it helps us to better understand how the Antarctic ice sheet interacts with the surrounding ocean.
Key Points
The radar stratigraphy in ice shelves is 9 times more sensitive to variability in snow deposition than to variability in basal melting
Some ice shelf channels at Roi Baudouin Ice Shelf deflect from flowlines; the radar stratigraphy reflects related processes
Variable snow deposition causes slow deflection, and basal melting can form ice shelf channel junctions far from the grounding line
In this paper, effects of birefringence on radio waves obliquely propagating though polar ice sheets are examined to facilitate interpretations of bistatic and side-looking radar data. A formalism ...applicable for arbitrary radar configurations is developed to predict the returned power from within and beneath the ice sheets that have arbitrary alignments of ice crystals (ice fabrics). We applied this formalism to a range of ice fabrics found in ice cores and assessed the effects of birefringence in terms of ray-path configurations, ice fabrics, and radar frequency. Predicted frequency dependence of the bed return power replicates prominent features observed at Greenland NGRIP ice-core site. Results show that birefringence in ice of 1 km or more thickness with strong (weak) fabric can reduce the power returned from the bed 2 dB or more at frequencies higher than 200 MHz (20 MHz) as compared to isotropic ice. This suggests that quantitative interpretation of the power returned from the bed requires careful assessment of birefringence almost everywhere over the ice sheets. Application of this formalism also suggests a radar-frequency range usable for attenuation measurements, possible effects of fabric on synthetic aperture radar processing, and a feasibility of remote sensing of ice fabric.
We present results of a multi-methodological approach to characterize the flow regime of West Ragnhild Glacier, the widest glacier in Dronning Maud Land, Antarctica. A new airborne radar survey ...points to substantially thicker ice (>2000 m) than previously thought. With a discharge estimate of 13–14 Gt yr−1, West Ragnhild Glacier thus becomes of the three major outlet glaciers in Dronning Maud Land. Its bed topography is distinct between the upstream and downstream section: in the downstream section (<65 km upstream of the grounding line), the glacier overlies a wide and flat basin well below the sea level, while the upstream region is more mountainous. Spectral analysis of the bed topography also reveals this clear contrast and suggests that the downstream area is sediment covered. Furthermore, bed-returned power varies by 30 dB within 20 km near the bed flatness transition, suggesting that the water content at bed/ice interface increases over a short distance downstream, hence pointing to water-rich sediment. Ice flow speed observed in the downstream part of the glacier (~250 m yr−1) can only be explained through very low basal friction, leading to a substantial amount of basal sliding in the downstream 65 km of the glacier. All the above lines of evidence (sediment bed, wetness and basal motion) and the relatively flat grounding zone give the potential for West Ragnhild Glacier to be more sensitive to external forcing compared to other major outlet glaciers in this region, which are more stable due to their bed geometry (e.g. Shirase Glacier).
Objective. This clinical trial was designed to investigate whether goshajinkigan reduces the onset of diabetic complications or not. Materials and Methods. A total of 332 type 2 diabetic mellitus ...patients were registered from 9 clinical centers from March 2000 to August 2007. Patients were randomly assigned to take goshajinkigan extract powder, 2.5 grams for 3 times a day or no kampo therapy, additionally to the regular treatment. The primary endpoints were the onset of macrovascular diseases or progression of nephropathy or retinopathy. Statistical analysis was performed by the intention-to-treat method. Results. After 5 years of observation, 116 patients were submitted to analysis. Among them, no macrovascular events were observed in both groups. Although 43 participants had upstaging of retinopathy or nephropathy in total, there was no significant difference between goshajinkigan group and control group. Deterioration of ankle reflex was suppressed in goshajinkigan group. Also glycated hemoglobin, and fasting plasma glucose were decreased in the goshajinkigan group. Conclusion. Although the power of analysis was too low to demonstrate any effects of goshajinkigan on the progression of macrovascular diseases, retinopathy or nephropathy, goshajinkigan may be beneficial for diabetic neuropathy and glycemic control.
Aim
To investigate the effects of tenascin‐C (TN‐C) on cultured rat dental pulp cells in relation to the expression of Notch signalling.
Methodology
Subcultured dental pulp cells derived from rat ...incisors were seeded both in wells and on plastic coverslips coated with various concentrations of recombinant human TN‐C. Expression of bone‐related mRNA was then analysed by RT‐PCR and observed by immunohistochemical staining. Encoding of Notch1 and Notch2 (markers of initial differentiation of odontoblast‐like cells), alkaline phosphatase (ALP), osteopontin (OPN) and osteocalcin (OCN) (markers of mineralization) was investigated. Non‐TN‐C‐coated wells were used as controls. Primary antibodies to Notch1, ALP and OCN were used for immunofluorescence staining, and ALP activity was evaluated. Data were compared using Student's t‐test.
Results
Cell proliferation rate in the experimental groups was significantly higher (P < 0.05) than that in the control group at 72 h. Expression of Notch1, Notch2, ALP, OPN and OCN mRNAs was significantly higher (P < 0.05) in the experimental group than that in the control group. Strongly positive staining for Notch1, ALP and OCN was observed in the experimental group. ALP activity was significantly higher (P < 0.01) in the experimental group than in the control group at 24 h.
Conclusion
TN‐C promoted differentiation of rat dental pulp cells by the activation of Notch.
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