PTF 11kx: a type Ia supernova with a symbiotic nova progenitor     

B Dilday  DA Howell  SB Cenko  JM Silverman  PE Nugent  M Sullivan  S Ben-Ami  L Bildsten  M Bolte  M Endl  AV Filippenko  O Gnat  A Horesh  E Hsiao  MM Kasliwal  D Kirkman  K Maguire  GW Marcy  K Moore  Y Pan  JT Parrent  P Podsiadlowski  RM Quimby  A Sternberg  N Suzuki  DR Tytler  D Xu  JS Bloom  A Gal-Yam  IM Hook  SR Kulkarni  NM Law  EO Ofek  D Polishook  D Poznanski 《Science (New York, N.Y.)》2012,337(6097):942-945

There is a consensus that type Ia supernovae (SNe Ia) arise from the thermonuclear explosion of white dwarf stars that accrete matter from a binary companion. However, direct observation of SN Ia progenitors is lacking, and the precise nature of the binary companion remains uncertain. A temporal series of high-resolution optical spectra of the SN Ia PTF 11kx reveals a complex circumstellar environment that provides an unprecedentedly detailed view of the progenitor system. Multiple shells of circumstellar material are detected, and the SN ejecta are seen to interact with circumstellar material starting 59 days after the explosion. These features are best described by a symbiotic nova progenitor, similar to RS Ophiuchi.  相似文献   

C-phycocyanin, a very potent and novel platelet aggregation inhibitor from Spirulina platensis     

Hsiao G  Chou PH  Shen MY  Chou DS  Lin CH  Sheu JR 《Journal of agricultural and food chemistry》2005,53(20):7734-7740

The aim of this study was to systematically examine the inhibitory mechanisms of C-phycocyanin (C-PC), one of the major phycobiliproteins of Spirulina platensis (a blue-green alga), in platelet activation. In this study, C-PC concentration-dependently (0.5-10 nM) inhibited platelet aggregation stimulated by agonists. C-PC (4 and 8 nM) inhibited intracellular Ca2+ mobilization and thromboxane A2 formation but not phosphoinositide breakdown stimulated by collagen (1 microg/mL) in human platelets. In addition, C-PC (4 and 8 nM) markedly increased levels of cyclic GMP and cyclic GMP-induced vasodilator-stimulated phosphoprotein (VASP) Ser(157) phosphorylation. Rapid phosphorylation of a platelet protein of Mw 47,000 (P47), a marker of protein kinase C activation, was triggered by phorbol-12,13-dibutyrate (150 nM). This phosphorylation was markedly inhibited by C-PC (4 and 8 nM). In addition, C-PC (4 and 8 nM) markedly reduced the electron spin resonance (ESR) signal intensity of hydroxyl radicals in collagen (1 microg/mL)-activated platelets. The present study reports on a novel and very potent (in nanomolar concentrations) antiplatelet agent, C-PC, which is involved in the following inhibitory pathways: (1) C-phycocyanin increases cyclic GMP/VASP Ser157 phosphorylation and subsequently inhibits protein kinase C activity, resulting in inhibition of both P47 phosphorylation and intracellular Ca2+ mobilization, and (2) C-PC may inhibit free radicals (such as hydroxyl radicals) released from activated platelets, which ultimately inhibits platelet aggregation. These results strongly indicate that C-PC appears to represent a novel and potential antiplatelet agent for treatment of arterial thromboembolism.  相似文献   

Determination of the antibiotic fungicide validamycin A in formulated products by micellar electrokinetic chromatography.   总被引：1，自引：0，他引：1  

Y M Hsiao  C C Lo 《Journal of agricultural and food chemistry》1999,47(9):3723-3726

A micellar electrokinetic capillary chromatographic method (MEKC) was used to determine validamycin A content in commercial products. The results indicated that this method was capable of analyzing the validamycin A content in formulated products with an instrument detection limit of 0.94 microg/mL and a method detection limit of 1. 70 microg/mL. Relative standard deviation (RSD) values of MEKC determination of validamycin A in formulated products ranged from 0. 61 to 2.09%. Recoveries of validamycin A in formulated products were in the region of 99.5-105.1%. All commercial products collected from markets contained validamycin A. The high percentage of recovery, the low detection limit, and the low RSD values confirmed that the MEKC technique is a senstivie and selective method.  相似文献   

Exploitation of Acacia confusa heartwood extract as natural photostabilizers     

Tzu-Cheng Chang  Nien-Chih Hsiao  Po-Cheng Yu  Shang-Tzen Chang 《Wood Science and Technology》2015,49(4):811-823

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Addiction liability of albino rats: breeding for quantitive differences in morphine drinking     

J R Nichols  S Hsiao 《Science (New York, N.Y.)》1967,157(788):561-563

Selective breeding produced two strains of rats that differ in their susceptibility to morphine addiction. Inbreeding the more susceptible rats in an unselected population produced susceptible offspring; inbreeding resistant rats produced resistant offspring. Further selection and inbreeding increased the strain difference in the F(2) and F(3) generations. The F(3) generation also differed in their susceptibility to alcohol addiction.  相似文献   

Speciation of Copper in Micropores     

Huang  Y.-J.  Wang  H. Paul  Hsiao  M. C.  Tai  C. C.  Huang  Hsin-Liang  Liu  S. H. 《Water, air, and soil pollution》2004,153(1-4):187-194

Speciation of copper in the micropores of zeolites and a contaminatedsoil was studied by extended X-ray absorption fine structural (EXAFS) spectroscopy. The Fourier transformed EXAFS data showed that copper oxide in zeolites ZSM-5 and ZSM-48 possessed a Cu-O bond distance of 1.95 Å with coordination numbers (CNs) of 1–2. Since ZSM-5 and ZSM-48 possessed channel openings of 5–6 Å, the possible sizes of the linear-type copper oxides in these confined pores were 2.93–2.95 Å. However, in the supercages (～13 Å) and channels (7.4 Å) of zeolite Y, a three dimensional structure of CuO was observed. Interestingly, we found that CuO in the Cu-contaminated soil had a similar structure to that in ZSM-5 or ZSM-48. Nevertheless, the EXAFS data indicated that the CNs of Cu-O and Cu-O-Cu were 0.4 and 0.3, respectively, suggesting a highly perturbed copper oxide in the irregular micropores of the contaminated soil.  相似文献   

Purification and characterization of acetylcholinesterase from oriental fruit fly [Bactrocera dorsalis (Hendel)] (Diptera: Tephritidae)     

Hsiao YM  Lai JY  Liao HY  Feng HT 《Journal of agricultural and food chemistry》2004,52(17):5340-5346

An acetylcholinesterase (AChE, EC 3.1.1.7) was purified from the head of the insecticide susceptible oriental fruit fly, Bactrocera dorsalis (Hendel), by affinity chromatography of Triton X-100 extract. The degree of purification was about 8183-fold with recoveries of 52%. The molecular mass of purified AChE was 116 kDa for its native protein (nonreduced form) and 61 kDa for its subunits (reduced form) as revealed on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), suggesting that the homodimer of AChE linked with disulfide bonds. Nondenaturing PAGE of the purified AChE revealed only one molecular form. The maximum velocities (V(max)) for hydrolyzing acetylthiocholine (ATC), propionylthiocholine, and S-butyrylthiocholine were 833.3, 222.2, and 57.5 micromol/min/mg, and the Michaelis constants (K(m)) were 87.9, 26.9, and 195.3 microM, respectively. More than 97% of AChE activity was inhibited by 10 microM eserine or BW284C51, but only 53% of the activity was inhibited by ethopropazine at the same concentration. On the basis of the substrate and inhibitor specificities, the purified enzyme appeared to be a true AChE. Nevertheless, the purified AChE exhibited some distinctive characteristics including (i) a lack of the substrate inhibition phenomenon when using ATC as the hydrolyzing substrate and (ii) a higher V(m) value for ATC than AChE from other insect species. These biochemical properties may show that AChE purified from the oriental fruit fly may have structural differences from those of other insect species.  相似文献   

All hermaphrodite progeny are derived by self-pollinating the sunrise papaya mutant     

C. Chan-Tai  C.-R. Yen    L.-S. Chang    C.-H. Hsiao  T.-S. Ko  W. E. Weber 《Plant Breeding》2003,122(5):431-434

Self‐pollination of a hermaphroditic cultivar normally gives a ratio of 2 : 1 hermaphrodite to female papayas with genotypes M₂m and mm, respectively. Much effort has been dedicated to marking the sexual types of papaya at the seedling stage to distinguish hermaphroditic from female papayas. A hermaphroditic papaya mutant (SR*) has been obtained, derived from the ‘Sunrise’ papaya cultivar mutant. Self‐pollination of the mutant resulted in all progenies being hermaphroditic. The genotype of the female was lethal, as a result of a lethal gene being linked to the mm female gene complex in this case. However, a 3 : 1 segregation ratio was obtained from the progeny of the hermaphroditic cultivar ‘Thailand’ crossed with SR*, indicating that all genotypes survived. Homozygous genotypes (M₂M₂) would be lethal according to Storey's model. Randomly selected F1 plants of the ‘Thailand’ SR* combination were self‐pollinated to obtain an F₂ generation. The F₂ segregation ratio suggested that the SR* mutant had a different form of the M₂ allele, now designated as M_@, which allowed the dominant M_@M₂ to survive in cross combinations. Genetic study has proved that SR* has the M_@ml genotype, a new mutant. It is capable of producing all hermaphroditic papaya progenies.  相似文献   

A direct multiplex loop-mediated isothermal amplification method to detect three CITES-listed shark species     

Tzu-Chun Lin  Wanchien Victoria Hsiao  Shang-Jung Han  Shoou-Jeng Joung  Jen-Chieh Shiao 《水产资源保护:海洋与淡水生态系统》2021,31(8):2193-2203

1. Species identification of sharks under catch or trade regulations is important for law enforcement and species conservation. Rapid detection of Convention on the International Trade in Endangered Species (CITES)-listed species is needed for on-site screening.
2. Species-specific primers were designed to target three mitochondrial genes (ND2, COI, and CytB) in both the simplex and multiplex loop-mediated isothermal amplification (LAMP) assay for the pelagic thresher shark (Alopias pelagicus), the bigeye thresher shark (Alopias superciliosus), and the scalloped hammerhead shark (Sphyrna lewini), respectively. Another primer set designed to target S. lewini was used for detection-limit testing of the LAMP assay.
3. The refined direct multiplex LAMP was used to detect the three CITES-listed shark species and omitted the lengthy DNA extraction process. A homogenizer was used to release the DNA from the shark tissues, and a simplex or multiplex LAMP reaction was conducted for 30 min in an incubator at 65°C using species-specific primer sets.
4. Positive LAMP reactions showed a colour change from pink to yellow, whereas negative reactions showed no colour change. Multiplex LAMP assays were performed using 84 samples, which successfully identified the target and non-target species and provided a fast (<1 h), simple, and reliable method to distinguish three CITES-listed shark species from the other non-target species, for either fresh or dry fin products.
5. Results of this study and the method developed will play a critical role in assisting fishery agencies and customs officials in identifying the illegal catch and trade of CITES-listed shark species.

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Antioxidant activity of fermented soybean extract     

Hu CC  Hsiao CH  Huang SY  Fu SH  Lai CC  Hong TM  Chen HH  Lu FJ 《Journal of agricultural and food chemistry》2004,52(18):5735-5739

Free radicals are considered to be important causative factors in the development of cancer and cardiovascular diseases. This relationship has led to interest in evaluating the antioxidant capacities of many dietary supplements. Fermented soybean extract is produced by symbiotic fermentation of organic soybean with 20 types of Lactobacillus and yeast. In vitro and in vivo models are used in this study to evaluate the antioxidant effect of fermented soybean extract. Several in vitro models are used to detect the antioxidant capacity of the fermented soybean extract, which is compared to vitamin C and Trolox. The results demonstrate that the fermented soybean extract has strong antioxidant activity against unsaturated fatty acid peroxidation compared to vitamin C and Trolox. By the means of the test system developed by Y. Toshiki et al., it is shown that the fermented soybean extract can function both as an antioxidant and as a free radical acceptor that can convert free radicals into harmless substances through an energy-decreasing procedure. An in vivo study examines the effects of fermented soybean extract on the activity of antioxidant enzymes. The activities of the antioxidant enzymes (AOE) including total superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPX) are measured in liver, kidney, and brain from male Sprague-Dawley rats. The activities of CAT, SOD, and GPX are increased in the liver. However, the SOD activity is decreased in the kidney. SOD and GPX activities are decreased in the brain. These results lead to the conclusion that fermented soybean extract not only has antioxidant activity but also has an effect on the activity of antioxidant enzymes in liver.  相似文献