Formation and evolution of carbonaceous asteroid Ryugu: Direct evidence from returned samples.

Samples of the carbonaceous asteroid Ryugu were brought to Earth by the Hayabusa2 spacecraft. We analyzed 17 Ryugu samples measuring 1 to 8 millimeters. Carbon dioxide-bearing water inclusions are present within a pyrrhotite crystal, indicating that Ryugu's parent asteroid formed in the outer Solar System. The samples contain low abundances of materials that formed at high temperatures, such as chondrules and calcium- and aluminum-rich inclusions. The samples are rich in phyllosilicates and carbonates, which formed through aqueous alteration reactions at low temperature, high pH, and water/rock ratios of <1 (by mass). Less altered fragments contain olivine, pyroxene, amorphous silicates, calcite, and phosphide. Numerical simulations, based on the mineralogical and physical properties of the samples, indicate that Ryugu's parent body formed ~2 million years after the beginning of Solar System formation.

Sample collection from asteroid (162173) Ryugu by Hayabusa2: Implications for surface evolution.

The near-Earth asteroid (162173) Ryugu is thought to be a primitive carbonaceous object that contains hydrated minerals and organic molecules. We report sample collection from Ryugu's surface by the Hayabusa2 spacecraft on 21 February 2019. Touchdown images and global observations of surface colors are used to investigate the stratigraphy of the surface around the sample location and across Ryugu. Latitudinal color variations suggest the reddening of exposed surface material by solar heating and/or space weathering. Immediately after touchdown, Hayabusa2's thrusters disturbed dark, fine grains that originate from the redder materials. The stratigraphic relationship between identified craters and the redder material indicates that surface reddening occurred over a short period of time. We suggest that Ryugu previously experienced an orbital excursion near the Sun.

The surface composition of asteroid 162173 Ryugu from Hayabusa2 near-infrared spectroscopy.

The near-Earth asteroid 162173 Ryugu, the target of the Hayabusa2 sample-return mission, is thought to be a primitive carbonaceous object. We report reflectance spectra of Ryugu's surface acquired with the Near-Infrared Spectrometer (NIRS3) on Hayabusa2, to provide direct measurements of the surface composition and geological context for the returned samples. A weak, narrow absorption feature centered at 2.72 micrometers was detected across the entire observed surface, indicating that hydroxyl (OH)-bearing minerals are ubiquitous there. The intensity of the OH feature and low albedo are similar to thermally and/or shock-metamorphosed carbonaceous chondrite meteorites. There are few variations in the OH-band position, which is consistent with Ryugu being a compositionally homogeneous rubble-pile object generated from impact fragments of an undifferentiated aqueously altered parent body.

Hayabusa2 arrives at the carbonaceous asteroid 162173 Ryugu-A spinning top-shaped rubble pile.

The Hayabusa2 spacecraft arrived at the near-Earth carbonaceous asteroid 162173 Ryugu in 2018. We present Hayabusa2 observations of Ryugu's shape, mass, and geomorphology. Ryugu has an oblate "spinning top" shape, with a prominent circular equatorial ridge. Its bulk density, 1.19 ± 0.02 grams per cubic centimeter, indicates a high-porosity (>50%) interior. Large surface boulders suggest a rubble-pile structure. Surface slope analysis shows Ryugu's shape may have been produced from having once spun at twice the current rate. Coupled with the observed global material homogeneity, this suggests that Ryugu was reshaped by centrifugally induced deformation during a period of rapid rotation. From these remote-sensing investigations, we identified a suitable sample collection site on the equatorial ridge.

Identification and localization of a neuron-specific isoform of TAF1 in rat brain: implications for neuropathology of DYT3 dystonia.

The neuron-specific isoform of the TAF1 gene (N-TAF1) is thought to be involved in the pathogenesis of DYT3 dystonia, which leads to progressive neurodegeneration in the striatum. To determine the expression pattern of N-TAF1 transcripts, we developed a specific monoclonal antibody against the N-TAF1 protein. Here we show that in the rat brain, N-TAF1 protein appears as a nuclear protein within subsets of neurons in multiple brain regions. Of particular interest is that in the striatum, the nuclei possessing N-TAF1 protein are largely within medium spiny neurons, and they are distributed preferentially, though not exclusively, in the striosome compartment. The compartmental preference and cell type-selective distribution of N-TAF1 protein in the striatum are strikingly similar to the patterns of neuronal loss in the striatum of DYT3 patients. Our findings suggest that the distribution of N-TAF1 protein could represent a key molecular characteristic contributing to the pattern of striatal degeneration in DYT3 dystonia.

Potential for the replication of the betanodavirus redspotted grouper nervous necrosis virus in human cell lines.

The determination of the host ranges of viruses is important because of the possible emergence of infectious agents, which may result from the zoonotic transmission of animal viruses to humans. The family Nodaviridae, whose members are non-enveloped, positive-stranded bipartite RNA viruses, is comprised of the genera Alphanodavirus and Betanodavirus, whose members predominantly infect insects and fish, respectively. The alphanodaviruses can also infect suckling mice and suckling hamsters, resulting in paralysis and death. Pigs near the site of isolation of the Nodamura virus (NoV), an alphanodavirus, have been reported to have high levels of NoV neutralizing antibody, suggesting that they may be part of the natural host range of this virus. Betanodaviruses are the causative agents of viral nervous necrosis, which occurs in several species of fish. However, little is known regarding the mechanism of infection of these viruses. Whether betanodaviruses can infect hosts other than fish remains unclear. In this study, we examined the possibility that a betanodavirus, redspotted grouper nervous necrosis virus (RGNNV), can infect human cell lines and showed that this virus can attach to the cells but cannot penetrate them, although human cells can support the replication of the betanodavirus when viral RNAs are transfected. The betanodavirus in its present form cannot infect human cells.

Inhibition of betanodavirus infection by inhibitors of endosomal acidification.

Betanodaviruses, members of the family Nodaviridae, have small positive-stranded bipartite RNA genomes and are the causal agent of viral nervous necrosis (VNN) in many species of marine farmed fish. In the aquaculture industry, outbreaks of betanodavirus infection and spread in larval and juvenile fish result in devastating damage and heavy economic loss. Although an urgent need exists to develop drugs that inhibit betanodavirus infection, there have been no reports about anti-betanodavirus drugs. Recently, it was reported that betanodaviruses were detected in the endosomes of infected cells, suggesting that betanodaviruses enter fish cells by endocytosis. This finding prompted us to examine whether blocking this endosomal pathway could provide a target for antiviral drug development. In this study, we examined the inhibitory effect of several lysosomotropic agents against betanodavirus infection in fish E-11 cells. The presence of 1 mM NH4Cl or 1 microM chloroquine in the medium inhibited the entry of betanodaviruses into cells and inhibited viral infection. The lysosomotropic agents bafilomycin A1 and monensin also inhibited virus-induced cytopathology and virus production. Our data demonstrate that inhibitors of endosomal acidification are candidates as antiviral agents against betanodavirus.

Viral infectious disease and natural products with antiviral activity.

Viral diseases, such as acquired immunodeficiency syndrome (AIDS), respiratory diseases, and hepatitis, are the leading causes of death in humans worldwide, despite the tremendous progress in human medicine. The lack of effective therapies and/or vaccines for several viral infections, and the rapid emergence of new drug-resistant viruses have urged a growing need for developing new and effective chemotherapeutic agents to treat viral diseases. Recent advances in the understanding of both the cellular and molecular mechanisms of virus replication have provided the basis for novel therapeutic strategies. Several hundred natural products have been isolated for screening and identifying antiviral activity, and some have been shown to have great medicinal value in preventing and/or ameliorating viral diseases in preclinical and clinical trials. There are innumerable potentially useful medicinal plants and herbs waiting to be evaluated and exploited for therapeutic applications against genetically and functionally diverse virus families. This review focuses on several selected pathogenic viruses, including the human immunodeficiency virus (HIV), influenza virus, hepatitis B and C viruses and herpes viruses, and antiviral natural compounds from medicinal plants (herbs), while paying particular attention to promising compounds in preclinical and clinical trials. We also focused our attention on the need to develop effective screening systems for antiviral activity.

Near-infrared spectral results of asteroid Itokawa from the Hayabusa spacecraft.

The near-infrared spectrometer on board the Japanese Hayabusa spacecraft found a variation of more than 10% in albedo and absorption band depth in the surface reflectance of asteroid 25143 Itokawa. Spectral shape over the 1-micrometer absorption band indicates that the surface of this body has an olivine-rich mineral assemblage potentially similar to that of LL5 or LL6 chondrites. Diversity in the physical condition of Itokawa's surface appears to be larger than for other S-type asteroids previously explored by spacecraft, such as 433 Eros.

Detailed images of asteroid 25143 Itokawa from Hayabusa.

Rendezvous of the Japanese spacecraft Hayabusa with the near-Earth asteroid 25143 Itokawa took place during the interval September through November 2005. The onboard camera imaged the solid surface of this tiny asteroid (535 meters by 294 meters by 209 meters) with a spatial resolution of 70 centimeters per pixel, revealing diverse surface morphologies. Unlike previously explored asteroids, the surface of Itokawa reveals both rough and smooth terrains. Craters generally show unclear morphologies. Numerous boulders on Itokawa's surface suggest a rubble-pile structure.

Raised plasma oxidised LDL in acute cerebral infarction.

BACKGROUND: The association between oxidised low density lipoprotein (OxLDL) and cerebral infarction is suspected but not established. OBJECTIVES: To determine whether plasma OxLDL is a useful marker for monitoring oxidative stress in stroke patients. METHODS: Plasma OxLDL concentrations were determined in 56 stroke patients with cerebral infarction (n = 45) or cerebral haemorrhage (n = 11), and in 19 age matched controls, using a novel sandwich enzyme linked immunosorbent assay. RESULTS: Compared with the controls (0.130 (0.007) ng/ micro g LDL, mean (SEM)), OxLDL was significantly raised in patients with cerebral infarction (0.245 (0.022); p < 0.0001) but not in those with haemorrhage (0.179 (0.023)). Patients with cortical ischaemic infarcts (n = 22) had higher OxLDL levels than either the controls (p < 0.0001) or the patients with non-cortical ischaemic infarcts (n = 23) (p < 0.001). Increased OxLDL concentrations in patients with cortical infarcts persisted until the third day after stroke onset. The National Institutes of Health stroke scales in patients with cortical infarction were higher than in those with non-cortical infarction (p < 0.01). CONCLUSIONS: There is a significant association between raised plasma OxLDL and acute cerebral infarction, especially cortical infarction. Plasma OxLDL may reflect oxidative stress in stroke patients.

Analysis of Helicobacter pylori binding site on HEp-2 cells and three cell lines from human gastric carcinoma.

Helicobacter pylori (H. pylori) is a pathogen responsible for chronic gastritis and peptic ulcer diseases. It colonises the gastric mucus layer and adheres to the gastric epithelial cell surface. As this adherence is the first step of infection, it is important to study the adherence mechanism. The aim of this study was to analyse the specific binding assay of H. pylori to HEp-2 cells and three gastric phenotype cell lines, AGS, MKN-45 and AZ-521. H. pylori NCTC 11637 grown on agar plates was harvested and used in experiments. H. pylori was inoculated to pre-cultured cell monolayers. Adhered bacteria were labelled with an anti-H. pylori antibody and an FITC-conjugated secondary antibody and quantified by using a fluorescent plate reader. Microbial adherence to HEp-2 cells increased with incubation time and incubated concentration of H. pylori. No further increase was obtained with four or more hours of incubation or with a concentration of 4 x 10(7) bacteria/well or more. Scatchard analysis revealed a linear plot and the Bmax value was 88.3. Similar adherence patterns were obtained when AGS, AZ-521 and MKN-45 cells were used for adherence assays, but they had a lower binding affinity than HEp-2 cells and AZ-521. MKN-45 cells had less receptors than HEp-2 and AGS cells. In conclusion, H. pylori adhered to the cell surface could be quantified by this assay method. H. pylori adhesion to cell surfaces has a single population of binding site and one type of binding site on HEp-2, AGS, AZ-521 and MKN-45 cells.

Effect of depolymerized holothurian glycosaminoglycan (DHG) on tissue factor pathway inhibitor: in vitro and in vivo studies.

Depolymerized holothurian glycosaminoglycan (DHG) is a glycosaminoglycan extracted from the sea cucumber Stichopus japonicus Selenka. In previous studies, we demonstrated that DHG has antithrombotic and anticoagulant activities that are distinguishable from those of heparin and dermatan sulfate. In the present study, we examined the effect of DHG on the tissue factor pathway inhibitor (TFPI), which inhibits the initial reaction of the tissue factor (TF)-mediated coagulation pathway. We first examined the effect of DHG on factor Xa inhibition by TFPI and the inhibition of TF-factor VIIa by TFPI-factor Xa in in vitro experiments using human purified proteins. DHG increased the rate of factor Xa inhibition by TFPI, which was abolished either with a synthetic C-terminal peptide or with a synthetic K3 domain peptide of TFPI. In contrast, DHG reduced the rate of TF-factor VIIa inhibition by TFPI-factor Xa. Therefore, the effect of DHG on in vitro activity of TFPI appears to be contradictory. We then examined the effect of DHG on TFPI in cynomolgus monkeys and compared it with that of unfractionated heparin. DHG induced an increase in the circulating level of free-form TFPI in plasma about 20-fold when administered i.v. at 1 mg/kg. The prothrombin time (PT) in monkey plasma after DHG administration was longer than that estimated from the plasma concentrations of DHG. Therefore, free-form TFPI released by DHG seems to play an additive role in the anticoagulant mechanisms of DHG through the extrinsic pathway in vivo. From the results shown in the present work and in previous studies, we conclude that DHG shows anticoagulant activity at various stages of coagulation reactions, i.e., by inhibiting the initial reaction of the extrinsic pathway, by inhibiting the intrinsic Xase, and by inhibiting thrombin.

Neutralization of DHG, a new depolymerized holothurian glycosaminoglycan, by protamine sulfate and platelet factor 4.

The neutralization of depolymerized holothurian glycosaminoglycan (DHG), unfractionated heparin (UFH), and low-molecular-weight heparin (LMWH) by protamine sulfate (PS) or platelet factor 4 (PF4) was studied. In in vitro studies, the prolongation of thrombin clotting time (TCT) by these glycosaminoglycans was completely neutralized by PS, whereas activated partial thromboplastin time (APTT) was relatively resistant to neutralization. In rats, prolongation of bleeding time by DHG was neutralized by PS with concomitant normalization of TCT ex vivo. Heparin-cofactor-II-dependent antithrombin activity of DHG or UFH was neutralized by PF4 at a high concentration to the same extent; however, prolongation of the APTT by DHG was more resistant to neutralization by PF4 at a physiological plasma level than that by UFH. In conclusion, since the prolongation of bleeding time by DHG was neutralized by PS with concomitant normalization of TCT, and since PF4 neutralized the antithrombin activity of DHG, these proteins may be useful as antidotes for DHG to prevent bleeding in case of an overdose.

The anticoagulant and hemorrhagic effects of DHG, a new depolymerized holothurian glycosaminoglycan, on experimental hemodialysis in dogs.

We studied the use of depolymerized holothurian glycosaminoglycan (DHG) as an anticoagulant in experimental beagle-dog hemodialysis using a hollow-fiber dialyzer compared to that using unfractionated heparin (UFH), low-molecular-weight heparin (LMWH), and nafamostat mesilate (FUT). Effectiveness was based on 5 h hemodialysis and no marked clot deposition in the extracorporeal circuit. At effective doses, UFH and LMWH significantly prolonged template bleeding time, in sharp contrast to FUT and DHG, which scarcely prolonged bleeding time during hemodialysis. DHG prolonged activated partial thromboplastin time (APTT) about 6 times that of normal plasma and prolonged thrombin clotting time (TCT) markedly; FUT showed marked APTT prolongation but hardly prolonged TCT in the hemodialysis circuit at the effective dose. The anticoagulant profile of DHG thus differs completely from that of FUT. These results suggest that DHG may be useful as anticoagulant for hemodialysis with low hemorrhagic risk.

Antithrombin III-independent effect of depolymerized holothurian glycosaminoglycan (DHG) on acute thromboembolism in mice.

A previous study in this laboratory showed that depolymerized holothurian glycosaminoglycan (DHG) has two different antithrombin III (ATIII)-independent inhibitory effects on the in vitro blood coagulation system: heparin cofactor II (HCII)-dependent inhibition of thrombin, and ATIII- and HCII-independent inhibition of factor X activation by factor IXa-factor VIIIa complex (Nagase et al. Blood 85, 1527-1534, 1995). In the present study, we compared the antithrombotic effects of DHG in normal and in ATIII-deficient mice with those of unfractionated heparin (UFH) and low molecular weight heparin (LMWH). DHG, unlike UFH and LMWH, exerted an in vivo antithrombotic effect even in mice with decreased plasma ATIII activity (about 30% of normal). We then compared the anticoagulant and antithrombotic effects of DHG in mice with those of high molecular weight (HMW)-DHG, low molecular weight (LMW)-DHG, and dermatan sulfate (DS). In terms of in vitro anticoagulant activity assessed by use of purified human components, DHGs (DHG, HMW-DHG, and LMW-DHG) had different anti-thrombin activity in the presence of HCII and anti-factor Xase activities, which differences were dependent on the molecular weight. With respect to in vivo antithrombotic activity, DHG, HMW-DHG, and LMW-DHG showed almost the same inhibitory effect on acute thromboembolism in mice (minimum effective dose [MED]: > 0.3 mg/kg). Since the antithrombotic activities of DHGs were not correlated with the anticoagulant-specific activities, the contribution of the two anticoagulant activities to the in vivo antithrombotic effect of DHGs remains unknown. However, DHG was more effective against acute thromboembolism in mice than DS (MED > 1 or > 3 mg/kg), which showed no inhibitory activity toward factor Xase. Therefore, it seems that factor Xase inhibition contributes greatly to the antithrombotic effect of DHG and that DHG exerts this effect in mice mainly by inhibiting factor Xase.

DHG, a new depolymerized holothurian glycosaminoglycan, exerts an antithrombotic effect with less bleeding than unfractionated or low molecular weight heparin, in rats.

We characterized the antithrombotic, haemorrhagic, and ex vivo anticoagulant effects of a recently identified depolymerized holothurian glycosaminoglycan (DHG), and compared these effects with those of unfractionated heparin (UFH), low molecular weight heparin (LMWH), and dermatan sulfate (DS). In thrombin-induced venous thrombus formation in rats, DHG had a significant preventive effect at 0.3 mg/kg or more at 5 min after i.v., administration. UFH, LMWH, and DS also showed a significant antithrombotic effect at 0.3, 0.3, and 1 mg/kg, respectively, under the same experimental conditions. After rat tail transection, DHG, UFH, LMWH, and DS prolonged the bleeding time significantly at 10, 1, 1, and 10 mg/kg, respectively, at 5 min after i.v., injection. Therefore, DHG exerts its antithrombotic effect with less bleeding than UFH and LMWH in experimental animals. DHG prolonged the activated partial thromboplastin time in a dose-dependent manner at 0.3-3 mg/kg, at which dose an antithrombotic effect was exhibited without any significant haemorrhagic effect. All of these glycosaminoglycans prolonged thrombin clotting time markedly at their haemorrhagic doses.

Interaction of a new depolymerized holothurian glycosaminoglycan with proteins in human plasma.

In a rat template bleeding model, depolymerized holothurian glycosaminoglycan (DHG) prolonged bleeding time at 30 mg/kg i.v. but unfractionated heparin (UFH) had the same effect at 1 mg/kg i.v., indicating that DHG is much less bleeding than UFH. To characterize this difference, we examined the affinity of DHG for plasma proteins by means of a glycosaminoglycan-conjugated cellulofine column in comparison with that of UFH. The DHG column strongly bound factor V, factor IX, protein S, histidine-rich glycoprotein, platelet factor 4 (PF4), beta-thromboglobulin, von Willebrand factor, fibronectin, and heparin cofactor II, but did not bind fibrinogen, prothrombin, factor VII, protein C, antithrombin III (ATIII), plasminogen or alpha 2-plasmin inhibitor. The profile of protein binding to the UFH column was almost the same as that of the DHG column except that ATIII showed affinity for UFH. One of the reasons why DHG caused much less bleeding than UFH is thus suggested to be the differences in their affinity for ATIII in plasma.

Effect of depolymerized holothurian glycosaminoglycan (DHG) on the activation of factor VIII and factor V by thrombin.

Our previous study has shown that depolymerized holothurian glycosaminoglycan (DHG) has two different inhibitory activities in the blood coagulation cascade: heparin cofactor II-dependent thrombin inhibition; and antithrombin III- and heparin cofactor II-independent inhibition of the intrinsic factor Xase complex [Nagase et al. (1995) Blood 85, 1527-1534]. In the present study, the effect of DHG on the activation of factor VIII and factor V by thrombin was examined with purified human components. DHG inhibited the activation of factor VIII by thrombin at concentrations exceeding 80 nM, but not the activation of factor V by thrombin at concentrations of up to 8 mu M. On Western blot analysis, DHG inhibited the cleavage of factor VIII light chain at concentrations exceeding 0.8 mu M. The interaction between DHG and factors VIII and V and thrombin was examined with a DHG-cellulofine column. DHG had strong affinity for factor V and thrombin, but slight affinity for factor VIII. The interaction of DHG with thrombin was analyzed, using fluorescein isothiocyanate-labeled DHG. One mole of DHG bound 2 mol of thrombin, with a dissociation constant (Kd) of 3.04 x 10(-6) M. These results suggest that DHG interferes with the interaction between thrombin and factor VIII, probably by making a binary complex through the anionic binding exosite II of thrombin.

Depolymerized holothurian glycosaminoglycan with novel anticoagulant actions: antithrombin III- and heparin cofactor II-independent inhibition of factor X activation by factor IXa-factor VIIIa complex and heparin cofactor II-dependent inhibition of thrombin.

The inhibition mechanism of a polysaccharide anticoagulant, depolymerized holothurian glycosaminoglycan (DHG), was examined by analyzing its effects on the clotting time of human plasma depleted of antithrombin III (ATIII), of heparin cofactor II (HCII), or of both heparin cofactors. The effect exerted by this agent on the activation of prothrombin and factor X in purified human components were also examined and all effects were compared with those of other glycosaminoglycans (GAGs). The capacity of DHG to prolong activated partial thromboplastin time was not reduced in ATIII-depleted, HCII-depleted, HCII-depleted, or ATIII- and HCII-depleted plasma, whereas its capacity to prolong prothrombin time and thrombin clotting time was reduced in HCII-depleted plasma. DHG inhibited the amidolytic activity of thrombin in the presence of HCII with a second order rate constant of 1.2 x 10(8) (mol/L)-1 min-1. These results indicated that DHG has two different inhibitory activities, one being an HCII-dependent thrombin inhibition and the other an ATIII- and HCII-independent inhibition of the coagulation cascade. The heparin cofactors-independent inhibitory activity of DHG was investigated in the activation of prothrombin by factor Xa and in the activation of factor X by tissue factor-factor VIIa complex or by factor IXa. DHG significantly inhibited the activation of factor X by factor IXa in the presence of factor VIIIa, but not in the absence of factor VIIIa. The interaction between DHG and factors IXa, VIIIa, and X was investigated with a DHG-cellulofine column, on which DHG had strong affinity for factors IXa and VIIIa. These findings show that the heparin cofactors-independent inhibition exhibited by DHG was caused by inhibition of the interaction of factor X with the intrinsic factor Xase complex, probably by binding to the factor IXa-factor VIIIa complex.