Micrometeorites (MMs) recovered from surface snow near the Dome Fuji Station, Antarctica are almost free from terrestrial weathering and contain very primitive materials, and are suitable for investigation of the evolution and interaction of inorganic and organic materials in the early solar system. We carried out a comprehensive study on seven porous and fluffy MMs [four Chondritic porous (CP) MMs and three fluffy fine-grained (Fluffy Fg) MMs] and one fine-grained type 1 (Fg C1) MM for comparison with scanning electron microscope, transmission electron microscope, X-ray absorption near-edge structure analysis, and secondary ion mass spectrometer.They show a variety of early aqueous activities. Four out of the seven CP MMs contain glass with embedded metal and sulfide (GEMS) and enstatite whiskers/platelets and do not have hydrated minerals. Despite the same mineralogy, organic chemistry of the CP MMs shows diversity. Two of them contain considerable amounts of organic materials with high carboxyl functionality, and one of them contains nitrile (C≡N) and/or nitrogen heterocyclic groups with D and 15 N enrichments, suggesting formation in the molecular cloud or a very low temperature region of the outer solar system. Another two CP MMs are poorer in organic materials than the above-mentioned MMs. Organic material in one of them is richer in aromatic C than the CP MMs mentioned above, being indistinguishable from those of hydrated carbonaceous chondrites. In addition, bulk chemical compositions of GEMS in the latter organic poor CP MMs are more homogeneous and have higher Fe/(Si+Mg+Fe) ratios than those of GEMS in the former organic-rich CP MMs. Functional group of the organic materials and amorphous silicate in GEMS in the organic-poor CP MMs may have transformed in the earliest stage of aqueous alteration, which did not form hydrated minerals.Three Fluffy Fg MMs contain abundant phyllosilicates, showing a clear evidence of aqueous alteration. Phyllosilicates in thee MMs are richer in Fe than those in hydrated IDPs, typical fine-grained hydrated (Fg C1) MMs, and hydrated carbonaceous chondrites. One of the Fluffy Fg MMs contains amorphous silicate, which is richer in Fe than GEMS and contains little or no nanophase Fe metal but contains Fe sulfide. Because the chemical compositions of the amorphous silicate are within the compositional field of GEMS in CP IDPs, the amorphous silicate may be alteration products of GEMS. The entire compositional field of GEMS in the CP MMs and the amorphous silicate in the Fluffy Fg MM matches that of the previously reported total compositional range of GEMS in IDPs.One Fluffy Fg MM contains Mg-rich phyllosilicate along with Fe-rich phyllosilicate and Mg-Fe carbonate. Mg-rich phyllosilicate and Mg-Fe carbonate may have been formed through the reaction of Fe-rich phyllosilicate, Mg-rich olivine and pyroxene, and water with C-bearing chemical species.These data indicate that CP MMs and Fluffy Fg MMs recovered from Antarctic surface snow contain materials that throw a light on the earl...

39A comprehensive study of organic chemistry and mineralogy of an ultracarbonaceous 40 micrometeorite (UCAMM D05IB80), collected from near the Dome Fuji Station, Antarctica, 41 has been carried out in order to understand the genetic relationship among organic materials, 42 silicates, and water. The micrometeorite is composed of a dense aggregate of ~5-µm-sized 43 hollow ellipsoidal organic material containing submicrometer-sized phases such as GEMS 44 and mineral grains. There is a wide area of organic material (~15 x 15 μm) in its interior. 45Low-Ca pyroxene is much more abundant than olivine and shows various Mg/(Mg+Fe) ratios 46 from ~1.0 to 0.78, which is common to previous works of UCAMM. By contrast, GEMS 47 amide. The ratio of nitrogen to carbon (N/C) in the smooth region of the organics is ~0.15, 53 which is five times higher than insoluble organic macromolecules in types 1 and 2 chondritic 54 meteorites. In addition, the UCAMM organics is soluble in epoxy, and thus it has 55 hydrophilicity. These polar natures indicate that the organic material in the UCAMM is very 56 primitive. The surface of the organics is coated with an inorganic layer with a few nanometers 57 thickness, which consists of C, O, Si, S, and Fe. Sulfur is also contained in the interior, 58implying the presence of organosulfur moieties. There is no isotopic anomaly of D, 13 C and 59 15 N in the organic material. 60Since interstellar photochemistry alone would not be able to explain the N/C ratio of the 61 UCAMM organics, we suggest that very small amount of fluid on a comet must have been 62 necessary for the formation of UCAMM. The GEMS grains depleted in Mg and S in the 63 UCAMM prove a very weak degree of aqueous alteration, which is weaker than that of 64 carbonaceous chondrites. Short-duration weak alteration probably caused by planetesimal 65 shock locally melts cometary ice grains and releases water that dissolves organics, while the 66 fluid unlikely mobilizes because of very low thermal conductivity of the porous icy body. 67 This event allows formation of a large organic puddle of the UCAMM, as well as organic 68 matter sulfurization, formation of mineral membrane-like thin layers, and deformation of 69 5 organic nanoglobules. 70 (408 words (max. 500 words)) 71 72 9 124 2. Experimental 125 The Antarctic snow, collected by the 51st JARE team of the National Institute of Polar 126 Research (NIPR), was melted and filtered in a class 1000 clean room at Ibaraki University, 127 and the residual particles were manually picked up under a binocular microscope. Details of 128 the micrometeorite collecting method are described by Sakamoto et al. (2010). They were 129 observed with JEOL JSM-5600LV scanning electron microscope (SEM) equipped with 130 energy dispersive spectrometer (EDS) at Ibaraki University and micrometeorites were 131selected from terrestrial materials based on the morphology and EDS spectra with chondritic 132 composition rich in Si, Mg, Fe, and O (see electronic supplementary data, S1). About 90 133 micrometeorites ...

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Angiogenesis is implicated in diverse pathological conditions such as cancer, rheumatoid arthritis, psoriasis, atherosclerosis, and retinal neovascularization. In the present study, we investigated the effects of modified rice bran hemicellulose (MRBH), a water-soluble hemicellulose preparation from rice bran treated with shiitake enzymes, on vascular endothelial growth factor (VEGF)-induced angiogenesis in vitro and its mechanism. We found that MRBH significantly inhibited VEGF-induced tube formation in human umbilical vein endothelial cells (HUVECs) co-cultured with human dermal fibroblasts. We also observed that MRBH dose-dependently suppressed the VEGF-induced proliferation and migration of HUVECs. Furthermore, examination of the anti-angiogenic mechanism indicated that MRBH reduced not only VEGF-induced activation of VEGF receptor 2 but also of the downstream signaling proteins Akt, extracellular signal-regulated protein kinase 1/2, and p38 mitogen-activated protein kinase. These findings suggest that MRBH has in vitro anti-angiogenic effects that are partially mediated through the inhibition of VEGF signaling.