Search for the Pair Production of Dark Particles X with K_{L}

We present the first search for the pair production of dark particles X via K_{L}^{0}→XX with X decaying into two photons using the data collected by the KOTO experiment. No signal was observed in the mass range of 40-110 MeV/c^{2} and 210-240 MeV/c^{2}. This sets upper limits on the branching fractions as B(K_{L}^{0}→XX)<(1-4)×10^{-7} and B(K_{L}^{0}→XX)<(1-2)×10^{-6} at the 90% confidence level for the two mass regions, respectively.

Toward High Precision XCO2 Retrievals From TanSat Observations: Retrieval Improvement and Validation Against TCCON Measurements.

TanSat is the 1st Chinese carbon dioxide (CO2) measurement satellite, launched in 2016. In this study, the University of Leicester Full Physics (UoL-FP) algorithm is implemented for TanSat nadir mode XCO2 retrievals. We develop a spectrum correction method to reduce the retrieval errors by the online fitting of an 8th order Fourier series. The spectrum-correction model and its a priori parameters are developed by analyzing the solar calibration measurement. This correction provides a significant improvement to the O2 A band retrieval. Accordingly, we extend the previous TanSat single CO2 weak band retrieval to a combined O2 A and CO2 weak band retrieval. A Genetic Algorithm (GA) has been applied to determine the threshold values of post-screening filters. In total, 18.3% of the retrieved data is identified as high quality compared to the original measurements. The same quality control parameters have been used in a footprint independent multiple linear regression bias correction due to the strong correlation with the XCO2 retrieval error. Twenty sites of the Total Column Carbon Observing Network (TCCON) have been selected to validate our new approach for the TanSat XCO2 retrieval. We show that our new approach produces a significant improvement on the XCO2 retrieval accuracy and precision when compared to TCCON with an average bias and RMSE of -0.08 ppm and 1.47 ppm, respectively. The methods used in this study can help to improve the XCO2 retrieval from TanSat and subsequently the Level-2 data production, and hence will be applied in the TanSat operational XCO2 processing.

Crustal anisotropy across northern Japan from receiver functions.

Northern Japan is a tectonically active area, with the presence of several volcanoes, and with frequent earthquakes among which the destructive Mw = 8.9-9.0 Tohoku-oki occurred on 11 March 2011. Tectonic activity leaves an imprint on the crustal structures, on both the upper and the lower layers. To investigate the crust in northern Japan, we construct a receiver function data set using teleseismic events recorded at 58 seismic stations belonging to the Japanese National (Hi-net) network. We isolate the signals, in the receiver function wavelet, that witness the presence of anisotropic structures at depth, with the aim of mapping the variation of anisotropy across the northern part of the island. This study focuses on the relation among anisotropy detected in the crust, stresses induced by plate convergence across the subduction zone, and the intrinsic characteristics of the rocks. Our results show how a simple velocity model with two anisotropic layers reproduces the observed data at the stations. We observe a negligible or small amount of signal related to anisotropy in the eastern part of the study area (i.e., the outer arc) for both upper and lower crust. Distinct anisotropic features are observed at the stations on the western part of the study area (i.e., the inner arc) for both upper and lower crust. The symmetry axes are mostly E-W oriented. Deviation from the E-W orientation is observed close to the volcanic areas, where the higher geothermal gradient might influence the deformation processes.

CDK4 and cyclin D1 allow human myogenic cells to recapture growth property without compromising differentiation potential.

In vitro culture systems of human myogenic cells contribute greatly to elucidation of the molecular mechanisms underlying terminal myogenic differentiation and symptoms of neuromuscular diseases. However, human myogenic cells have limited ability to proliferate in culture. We have established an improved immortalization protocol for human myogenic cells derived from healthy and diseased muscles; constitutive expression of mutated cyclin-dependent kinase 4, cyclin D1 and telomerase immortalized human myogenic cells. Normal diploid chromosomes were preserved after immortalization. The immortalized human myogenic cells divided as rapidly as primary human myogenic cells during the early passages, and underwent myogenic, osteogenic and adipogenic differentiation under appropriate culture conditions. The immortalized cells contributed to muscle differentiation upon xenotransplantation to immunodeficient mice under conditions of regeneration following muscle injury. We also succeeded in immortalizing cryopreserved human myogenic cells derived from Leigh disease patients following primary culture. Forced expression of the three genes shortened their cell cycle to < 30 h, which is similar to the doubling time of primary cultured human myogenic cells during early passages. The immortalization protocol described here allowed human myogenic cells to recapture high proliferation activity without compromising their differentiation potential and normal diploidy.

A quinol peroxidase inhibitor prevents secretion of a leukotoxin from Aggregatibacter actinomycetemcomitans.

BACKGROUND AND OBJECTIVE: Quinol peroxidase (QPO) catalyzes peroxidase activity using quinol in the respiratory chain as a substrate. Quinol peroxidase is essential for the secretion of leukotoxin (LtxA), which destroys leukocytes and erythrocytes in humans and is one of the major virulence factors of Aggregatibacter actinomycetemcomitans, which is associated with localized aggressive periodontitis. In the present study, we aimed to find a highly potent QPO inhibitor to attenuate the virulence of A. actinomycetemcomitans. MATERIAL AND METHODS: For screening of QPO inhibitors, QPO activity was measured kinetically by SpectraMax Plus with 96-well UV plates. Three hundred compounds in the Kitasato Institute for Life Sciences Chemical Library were screened. Secretion of LtxA in the culture supernatant was examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Cytotoxicity against human promyelocytic leukemia cell line (HL-60) cells from the culture supernatant was measured by Trypan Blue exclusion test. RESULTS: The present study characterized ascofuranone as a highly potent inhibitor of QPO (K(i) = 9.557 +/- 0.865 nm). Ascofuranone inhibited secretion of LtxA by A. actinomycetemcomitans in a dose-dependent manner, making A. actinomycetemcomitans less pathogenic to HL-60 cells. CONCLUSION: Quinol peroxidase inhibitors are promising candidates as alternative drugs for the treatment and prevention of the onset of localized aggressive periodontitis. Using ascofuranone as a seed compound, further study of QPO inhibitors could provide novel chemotherapeutic strategies for controlling localized aggressive periodontitis.

Quantification of seven arsenic compounds in seafood products by liquid chromatography/electrospray ionization-single quadrupole mass spectrometry (LC/ESI-MS).

A liquid chromatography/electrospray ionization-single quadrupole mass spectrometry (LC/ESI-MS) method was developed to quantify seven arsenic compounds: arsenate (As(V)), monomethylarsonic acid (MMA), dimethylarsinic acid (DMA), arsenobetaine (AB), trimethylarsine oxide (TMAO), arsenocholine (AC) and tetramethylarsonium ion (TEMA), widely found in seafood. The arsenicals separated by anion- or cation-exchange LC were all readily identified under the optimized ESI-MS conditions. Linear calibration curves constructed by plotting the peak area counts of molecular ions against the arsenic concentrations were obtained for all seven arsenic compounds. The limits of quantification (S/N = 10) were 800, 600, 50, 10, 5, 5 and 5 ng ml-1 for As(V), MMA, DMA, AB, TMAO, AC and TEMA, respectively. The LC/ESI-MS method was found to be useful to quantify arsenic compounds in seafood by model experiments using the mid-gut gland and muscle of a shellfish (Buccinid whelks). Spiking experiments verified the accuracy of the method.

Cephalopod tropomyosins: identification as major allergens and molecular cloning.

Heated extracts prepared from the mantle muscles (for decapods) or leg muscles (for octapods) of nine species of cephalopods were shown to be all reactive with serum IgE in crustacean-allergic patients. No marked difference in the reactivity with IgE was recognized among the cephalopods, suggesting that they are almost equally allergenic. Immunoblotting and inhibition immunoblotting data revealed that the major allergen is tropomyosin in common with the nine species of cephalopods and that the cephalopod tropomyosins are cross-reactive with one another and also with crustacean tropomyosins. Molecular cloning experiments first elucidated the primary structures of tropomyosins from five species of cephalopods. The cephalopod tropomyosins show high sequence identity (more than 92% identity) with one another, being the molecular basis for their cross-reactivity. Although the sequence identity between cephalopod and crustacean topomyosins is only about 63-64%, some of the IgE-binding epitopes proposed for brown shrimp Penaeus aztecus tropomyosin (Pen a 1) are well conserved in the cephalopod tropomyosins, supporting the cross-reactivity between cephalopod and crustacean tropomyosins.

Comparison of allergenicity and allergens between fish white and dark muscles.

BACKGROUND: Fish is one of the most frequent causes of immunoglobulin E (IgE)-mediated food allergy. Although the fish dark muscle is often ingested with the white muscle, no information about its allergenicity and allergens is available. METHODS: Heated extracts were prepared from both white and dark muscles of five species of fish and examined for reactivity with IgE in fish-allergic patients by enzyme-linked immunosorbent assay (ELISA) and for allergens by immunoblotting. Cloning of cDNAs encoding parvalbumins was performed by rapid amplification cDNA ends. Parvalbumin contents in both white and dark muscles were determined by ELISA using antiserum against mackerel parvalbumin. RESULTS: Patient sera were less reactive to the heated extract from the dark muscle than to that from the white muscle. A prominent IgE-reactive protein of 12 kDa, which was detected in both white and dark muscles, was identified as parvalbumin. Molecular cloning experiments revealed that the same parvalbumin molecule is contained in both white and dark muscles of either horse mackerel or Pacific mackerel. Parvalbumin contents were four to eight times lower in the dark muscle than in the white muscle. CONCLUSIONS: The fish dark muscle is less allergenic than the white muscle, because the same allergen molecule (parvalbumin) is contained at much lower levels in the dark muscle than in the white muscle. Thus, the dark muscle is less implicated in fish allergy than the white muscle.

[Emergent coronary artery bypass grafting using percutaneous cardiopulmonary support in a patient with a quadricuspid aortic valve; report of a case].

A 63-year-old man was admitted to our hospital for acute myocardial infarction. A cardiac catheter study showed 3 vessels coronary disease. He was treated by percutaneous coronary intervention for a left anterior descending arterial (LAD) lesion. Unfortunately, cardiac tamponade following stenting for LAD was complicated. A percutaneous cardiopulmonary support system was commenced along with an emergent coronary artery bypass grafting to the LAD and obtuse marginal branch. A quadricuspid aortic valve was discovered by an aortotomy and identified as Hurwitz-Roberts classification type b. Blood from the left coronary main trunk had already stopped. Intraaortic balloon pumping was instituted while weaning from the cardiopulmonary bypass. The patient's postoperative course was uneventful and all bypass grafts were sufficient. He was well 1 year after the operation.

Purification and characterization of an antibacterial protein in the skin secretion of rockfish Sebastes schlegeli.

An antibacterial protein in the skin secretion of rockfish (Sebastes schlegeli) was purified by lectin affinity chromatography on Con A-Sepharose and gel filtration on TSKgel G3000SW. The antibacterial protein featured the high molecular mass and selective action against Gram-negative bacteria. The molecular mass of the protein was estimated to be approximately 150 kDa in gel filtration and approximately 75 kDa by SDS-PAGE, suggesting that it is dimeric. The antibacterial principle was an acidic glycoprotein with pI 4.5, 3.4% reducing sugar and 2.8% amino sugar. Its sugar chains had N-type (high mannose-type) oligosaccharide and sialic acid components. It inhibited strongly the growth of Aeromonas salmonicida, Photobacterium damselae and Shewanella putrefaciens with a minimum inhibitory concentration (MIC) of approximately 3 microg/ml, and moderately the growth of Vibrio parahaemolyticus and A. hydrophila with a MIC of 12.5 microg/ml and 25 microg/ml, respectively. The values of the minimum bactericidal concentration were almost equivalent to those of MIC. The potent sensitivity against virulent pathogens such as A. hydrophila, A. salmonicida and P. damselae may contribute considerably to the innate host defense mechanism to combat microbes on the mucosal surfaces of the rockfish.

Purification, reactivity with IgE and cDNA cloning of parvalbumin as the major allergen of mackerels.

Three species of mackerels (Scomber japonicus, S. australasicus and S. scombrus) are widely consumed and considered to be most frequently involved in incidents of IgE-mediated fish allergy in Japan. In this study, parvalbumin, a possible candidate for the major allergen, was purified from the white muscle of three species of mackerels by gel filtration on Sephadex G-75 and reverse-phase HPLC on TSKgel ODS-120T. All the purified preparations from three species gave a single band of about 11 kDa and were clearly identified as parvalbumins by analyses of their partial amino acid sequences. In ELISA experiments, four of five sera from fish-allergic patients reacted to all the purified parvalbumins, demonstrating that parvalbumin is the major allergen in common with the mackerels. Antigenic cross-reactivity among the mackerel parvalbumins was also established by ELISA inhibition experiments. A cDNA library was constructed from the white muscle of S. japonicus and the cDNA encoding parvalbumin was cloned. The amino acid sequence translated from the nucleotide sequence revealed that the S. japonicus parvalbumin is composed of 108 residues, being a member of beta-type parvalbumins.

[Two cases of visceral larva migrans due to Ascaris suum showing a migratory nodular shadow].

The number of cases of visceral larva migrans caused by the pig ascarid, Ascaris suum has recently been increasing. We have encountered two cases of visceral larva migrans due to A. suum with a nodular shadow on the chest radiograph and eosinophilia in the peripheral blood. Patient 1 was a 26-year-old man who had been admitted to our hospital for an elective minor operation. His chest radiology and chest computed tomography revealed a nodule in the left lung field. Peripheral blood eosinophil counts and serum IgE values were elevated. Radiological abnormality disappeared without treatment. Patient 2 was a 57-year-old man who had been admitted to our hospital because of a migratory nodule on chest radiography and eosinophilia in the peripheral blood. The diagnosis of visceral larva migrans caused by A. suum was made because the serum of both patients was positive for an antibody against A. suum. Patient 1 and patient 2 were accustomed to eating the raw flesh of wild boar and deer, and of chicken and turkey, respectively. Treatment with albentazole was effective in these patients.

Potent antimalarial activities of polyether antibiotic, X-206.

In the course of our screening program to discover antimalarial antibiotics, which are active against drug resistant Plasmodium falciparum in vitro and rodents infected with P. berghei in vivo, from the culture broth of microorganisms, we found a selective and potent active substance produced by an actinomycete strain K99-0413. It was identified as a known polyether antibiotic, X-206. We also compared the in vitro antimalarial activities and cytotoxicities of 12 known polyethers with X-206. Among them, X-206 showed the most selective and potent inhibitory effect against both drug resistant and sensitive strains of P. falciparum. Comparison of biological activities and ion-affinities of the above antibiotics suggests that monovalent cations play an important biological role for the intracellular growth of P. falciparum in parasitized erythrocytes. Moreover, X-206 showed potent in vivo antimalarial activity on the rodent model, though the therapeutic window was narrow compared with its selective toxicity in vitro. These observations are the first report of antimalarial activity of X-206.

Total synthesis of nafuredin, a selective NADH-fumarate reductase inhibitor.

[structure: see text] Total synthesis of nafuredin, a selective NADH-fumarate reductase inhibitor, has been accomplished by a convergent approach. The C1-C8 and C9-C18 segments were derived efficiently from D-glucose and (S)-(-)-2-methyl-1-butanol, respectively, coupled by stereoselective Julia olefination, and converted to nafuredin.

Nafuredin, a novel inhibitor of NADH-fumarate reductase, produced by Aspergillus niger FT-0554.

A novel compound, nafuredin, was isolated as an inhibitor of anaerobic electron transport (NADH-fumarate reductase). It was obtained from culture broth of Aspergillus niger FT-0554 isolated from a marine sponge. The structure was elucidated as an epoxy-delta-lactone with an attached methylated olefinic side chain on the basis of spectral analysis.

Development of severe longitudinal atrophy of thoracic spinal cord following lupus-related myelitis.

A 26-year-old woman suffered from acute myelitis at Th 6 level associated with systemic lupus erythematosus. Methyl-prednisolone pulse therapy, intravenous high-dose immunoglobulin administration and plasmapheresis were not effective. Her neurological signs had persisted in spite of subsequent administration of oral prednisolone and azathiopurine. Magnetic resonance imaging (MRI) of spinal cord at the onset showed a marked swelling with intramedullary high intensity signals on T2WI along the whole thoracic cord. Three years later, MRI demonstrated a severe longitudinal and segmental atrophy of the mid to low thoracic cord which resulted in transverse spinal signs.

A convenient preparation of 3,3,3-trifluoro-1-propynylamines and their Lewis acid catalyzed reaction with carbonyl compounds leading to (z)-alpha-(trifluoromethyl)-alpha,beta-unsaturated amides.

N,N-Dialkyl(3,3,3-trifluoro-1-propynyl)amines were readily prepared by a three-step procedure starting from commercially available 2,2,3,3,3-pentafluoropropanol. These fluorinated alkynylamines reacted smoothly with a variety of aldehydes or ketones in the presence of a catalytic amount of Lewis acid and molecular sieves 4A at ambient temperature to produce the corresponding alpha-(trifluoromethyl)-alpha,beta-unsaturated amides in good to excellent yields with high Z-stereoselectivity.

Identification of collagen as a new fish allergen.

This study was intended to identify a high molecular weight allergen that had been detected in fish. Analyses by ELISA of five protein fractions prepared from bigeye tuna muscle showed that the high molecular weight allergen was contained in the myostromal protein fraction. Based on the results of SDS-PAGE, immunoblotting and amino acid analysis of the myostromal protein fraction, the high molecular weight allergen was judged to be collagen. Five of the eight patient sera used were found to react to the bigeye tuna collagen. In competitive ELISA inhibition experiments, the bigeye tuna collagen almost completely inhibited the IgE reactivity to the heated extracts from five species of fish, suggesting that collagen is commonly allergic regardless of fish species. However, no antigenic cross-reactivity was observed between collagens from fish and other animals.

Eph signalling functions downstream of Val to regulate cell sorting and boundary formation in the caudal hindbrain.

Rhombomeres are segmental units of the developing vertebrate hindbrain that underlie the reiterated organisation of cranial neural crest migration and neuronal differentiation. valentino (val), a zebrafish homologue of the mouse bzip transcription factor-encoding gene, kreisler, is required for segment boundary formation caudal to rhombomere 4 (r4). val is normally expressed in r5/6 and is required for cells to contribute to this region. In val(-) mutants, rX, a region one rhombomere in length and of mixed identity, lies between r4 and r7. While a number of genes involved in establishing rhombomeric identity are known, it is still largely unclear how segmental integrity is established and boundaries are formed. Members of the Eph family of receptor tyrosine kinases and their ligands, the ephrins, are candidates for functioning in rhombomere boundary formation. Indeed, expression of the receptor ephB4a coincides with val in r5/6, whilst ephrin-B2a, which encodes a ligand for EphB4a, is expressed in r4 and r7, complementary to the domain of val expression. Here we show that in val(-) embryos, ephB4a expression is downregulated and ephrin-B2a expression is upregulated between r4 and r7, indicating that Val is normally required to establish the mutually exclusive expression domains of these two genes. We show that juxtaposition of ephB4a-expressing cells and ephrin-B2a-expressing cells in the hindbrain leads to boundary formation. Loss of the normal spatial regulation of eph/ephrin expression in val mutants correlates not only with absence of boundaries but also with the inability of mutant cells to contribute to wild-type r5/6. Using a genetic mosaic approach, we show that spatially inappropriate Eph signalling underlies the repulsion of val(-) cells from r5/6. We propose that Val controls eph expression and that interactions between EphB4a and Ephrin-B2a mediate cell sorting and boundary formation in the segmenting caudal hindbrain.