Purification and characterization of the amylase from a small abalone <Emphasis Type="Italic">Haliotis sieboldii</Emphasis>     

Meng-Shun Hsieh  Li-Jung Yin  Shann-Tzong Jiang 《Fisheries Science》2008,74(2):425-432

ABSTRACT:   Amylase, with MW of 59 kDa, was purified from small abalone Haliotis sieboldii by ammonium sulfate fractionation, CM Sepharose Fast Flow and Sephacryl S-100 HR chromatographies. The optimal pH and temperature of purified amylase were 6.0 and 37°C, respectively. The purified enzyme was stable at pH 6.0–8.0 and low temperatures. It was activated by Ba²⁺, Mg²⁺, Ca²⁺, Co²⁺, Ni²⁺, Mn²⁺, K⁺, Ag⁺, Na⁺ and Li⁺, but completely or partially inhibited by Al³⁺, Cu²⁺, Cd²⁺, Hg²⁺ and Zn²⁺. EDTA could completely inhibit, while iodoacetamide, N-ethylmaleimide and urea partially inhibit the purified amylase. According to the digestion mode of various polysaccharides, the purified enzyme was considered to be an α-amylase.  相似文献   

Lunasin and Bowman-Birk protease inhibitor concentrations of protein extracts from enzyme-assisted aqueous extraction of soybeans     

Leite Nobrega de Moura JM  Hernandez-Ledesma B  de Almeida NM  Hsieh CC  de Lumen BO  Johnson LA 《Journal of agricultural and food chemistry》2011,59(13):6940-6946

Lunasin and Bowman-Birk protease inhibitor (BBI) are two soybean peptides to which health-promoting properties have been attributed. Concentrations of these peptides were determined in skim fractions produced by enzyme-assisted aqueous extraction processing (EAEP) of extruded full-fat soybean flakes (an alternative to extracting oil from soybeans with hexane) and compared with similar extracts from hexane-defatted soybean meal. Oil and protein were extracted by using countercurrent two-stage EAEP of soybeans at 1:6 solids-to-liquid ratio, 50 °C, pH 9.0, and 120 rpm for 1 h. Protein-rich skim fractions were produced from extruded full-fat soybean flakes using different enzyme strategies in EAEP: 0.5% protease (wt/g extruded flakes) used in both extraction stages; 0.5% protease used only in the second extraction stage; no enzyme used in either extraction stage. Countercurrent two-stage protein extraction of air-desolventized, hexane-defatted soybean flakes was used as a control. Protein extraction yields increased from 66% to 89-96% when using countercurrent two-stage EAEP with extruded full-fat flakes compared to 85% when using countercurrent two-stage protein extraction of air-desolventized, hexane-defatted soybean flakes. Extruding full-fat soybean flakes reduced BBI activity. Enzymatic hydrolysis reduced BBI contents of EAEP skims. Lunasin, however, was more resistant to both enzymatic hydrolysis and heat denaturation. Although using enzymes in both EAEP extraction stages yielded the highest protein and oil extractions, reducing enzyme use to only the second stage preserved much of the BBI and Lunasin.  相似文献   

Production and isolation of aflatoxin M1 for toxicological studies     

D P Hsieh  L M Beltran  M Y Fukayama  D W Rice  J J Wong 《Journal of the Association of Official Analytical Chemists》1986,69(3):510-512

One hundred mg aflatoxin M1 was produced and purified for toxicological studies. Aspergillus flavus NRRL 3251 was cultured on rice to produce aflatoxins B1, B2, M1, and M2, B1 and B2 were separated from M1 and M2 by a normal phase low pressure liquid chromatography (LC) column. M1 was then separated from M2 by a reverse phase low pressure LC column. Recoveries of aflatoxins from the LC columns were about 90%. The purified M1 was confirmed by ultraviolet-visible spectrometry, mass spectrometry, nuclear magnetic resonance spectrometry, optical rotation, and its mutagenicity to Salmonella typhimurium TA98.  相似文献   

Lactitol-based poly(ether polyol) hydrogels for controlled release chemical and drug delivery systems     

Han JH  Krochta JM  Kurth MJ  Hsieh YL 《Journal of agricultural and food chemistry》2000,48(11):5278-5282

The hydroxyl groups of lactitol were propoxylated to produce poly(ether polyol) (LPEP). The average pK(a) value of hydroxyl groups of the polyol was 1.63. Cross-linked hydrogels were synthesized by esterification with chlorinated poly(ethylene glycol) bis(carboxymethyl) ether (PEGBCOCl). The swelling ratio decreased with increasing cross-linking ratio (PEGBCOCl:LPEP) from 2:1 to 4:1 in the hydrogels and was sensitive to temperature change between 25 and 55 degrees C and concentrations of salt and glucose. The swelling ratio did not change significantly with pH in the range of 4-9. The release profiles of a model active agent, acetylsalicylic acid, from the hydrogels showed that the diffusional release rate had a half-order dependence on time, and the diffusivity decreased with increasing cross-linking ratio. This work demonstrated that LPEP-based hydrogels can be used for controlled delivery of drugs and agrochemicals and the release rates can be controlled with the cross-linking ratio of the hydrogel.  相似文献   

Analysis of mitochondrial DNA of an endangered beech species,Fagus hayatae Palibin ex Hayata     

Kato  Sumie  Koike  Takayoshi  Lei  Thomas T.  Hsieh  Chang-Fu  Ueda  Kunihiko  Mikami  Tetsuo 《New Forests》2000,19(1):109-114

Mitochondrial DNA restriction fragment length polymorphisms were used to examine cytoplasmic diversity within a relic-like population of Fagus hayatae, located in northern Taiwan. Fifteen trees were surveyed for three restriction endonucleases (BamHI, EcoRI and HindIII) and five mitochondrial gene probes (atpA, atp6, atp9, coxI and coxII). The analysis failed to reveal any polymorphisms, an observation that suggests cytoplasmic uniformity in the F. hayatae population examined. It is also interesting to note that the chondriome type of our F. hayatae samples is very close to that characteristic of F. crenata populations in the southernmost area of Japan.  相似文献   

A rabbit model of non-typhoidal Salmonella bacteremia     

Aruna Panda  Ivan Tatarov  Billie Jo Masek  Justin Hardick  Annabelle Crusan  Teresa Wakefield  Karen Carroll  Samuel Yang  Yu-Hsiang Hsieh  Michael M. Lipsky  Charles G. McLeod  Myron M. Levine  Richard E. Rothman  Charlotte A. Gaydos  Louis J. DeTolla 《Comparative immunology, microbiology and infectious diseases》2014

Bacteremia is an important cause of morbidity and mortality in humans. In this study, we focused on the development of an animal model of bacteremia induced by non-typhoidal Salmonella. New Zealand White rabbits were inoculated with a human isolate of non-typhoidal Salmonella strain CVD J73 via the intra-peritoneal route. Blood samples were collected at specific time points and at euthanasia from infected rabbits. Additionally, tissue samples from the heart, lungs, spleen, gastrointestinal tract, liver and kidneys were obtained at euthanasia. All experimentally infected rabbits displayed clinical signs of disease (fever, dehydration, weight loss and lethargy). Tissues collected at necropsy from the animals exhibited histopathological changes indicative of bacteremia. Non-typhoidal Salmonella bacteria were detected in the blood and tissue samples of infected rabbits by microbiological culture and real-time PCR assays. The development of this animal model of bacteremia could prove to be a useful tool for studying how non-typhoidal Salmonella infections disseminate and spread in humans.  相似文献   

Left-handed DNA in vivo   总被引：35，自引：0，他引：35  

A Jaworski  W T Hsieh  J A Blaho  J E Larson  R D Wells 《Science (New York, N.Y.)》1987,238(4828):773-777

Left-handed DNA is shown to exist and elicit a biological response in Escherichia coli. A plasmid encoding the gene for a temperature-sensitive Eco RI methylase (MEco RI) was cotransformed with different plasmids containing inserts that had varying capacities to form left-handed helices or cruciforms with a target Eco RI site in the center or at the ends of the inserts. Inhibition of methylation in vivo was found for the stable inserts with the longest left-handed (presumably Z) helices. In vitro methylation with the purified MEco RI agreed with the results in vivo. Supercoil-induced changes in the structure of the primary helix in vitro provided confirmation that left-handed helices were responsible for this behavior. The presence in vivo of left-handed inserts elicits specific deletions and plasmid incompatibilities in certain instances.  相似文献   

Autoradiography: technique for drastic reduction of exposure time to alpha particles     

J J Hsieh  F P Hungate  S A Wilson 《Science (New York, N.Y.)》1965,150(705):1821-1822

High-speed, gross, alpha autoradiographs can be made if silver-activated zinc sulfide is used as an intensifier in conjunction with high-speed film. The intensifier is interposed between the sample and film. This technique requires about 1/1000 of the exposure time required with Kodak NTB plates. The gross autoradiographs have greater contrast but slightly less resolution than conventional plates.  相似文献   

Dynamics of Saturn's magnetosphere from MIMI during Cassini's orbital insertion     

Krimigis SM  Mitchell DG  Hamilton DC  Krupp N  Livi S  Roelof EC  Dandouras J  Armstrong TP  Mauk BH  Paranicas C  Brandt PC  Bolton S  Cheng AF  Choo T  Gloeckler G  Hayes J  Hsieh KC  Ip WH  Jaskulek S  Keath EP  Kirsch E  Kusterer M  Lagg A  Lanzerotti LJ  Lavallee D  Manweiler J  McEntire RW  Rasmuss W  Saur J  Turner FS  Williams DJ  Woch J 《Science (New York, N.Y.)》2005,307(5713):1270-1273

The Magnetospheric Imaging Instrument (MIMI) onboard the Cassini spacecraft observed the saturnian magnetosphere from January 2004 until Saturn orbit insertion (SOI) on 1 July 2004. The MIMI sensors observed frequent energetic particle activity in interplanetary space for several months before SOI. When the imaging sensor was switched to its energetic neutral atom (ENA) operating mode on 20 February 2004, at approximately 10(3) times Saturn's radius RS (0.43 astronomical units), a weak but persistent signal was observed from the magnetosphere. About 10 days before SOI, the magnetosphere exhibited a day-night asymmetry that varied with an approximately 11-hour periodicity. Once Cassini entered the magnetosphere, in situ measurements showed high concentrations of H+, H2+, O+, OH+, and H2O+ and low concentrations of N+. The radial dependence of ion intensity profiles implies neutral gas densities sufficient to produce high loss rates of trapped ions from the middle and inner magnetosphere. ENA imaging has revealed a radiation belt that resides inward of the D ring and is probably the result of double charge exchange between the main radiation belt and the upper layers of Saturn's exosphere.  相似文献   

Retraction     

Tracy RB  Hsieh CL  Lieber MR 《Science (New York, N.Y.)》2000,289(5482):1141

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