Effects of dizocilpine pretreatment on parvalbumin immunoreactivity and Fos expression after cerebral ischemia in the hippocampus of the Mongolian gerbil     

Kwon YB  Yang IS  Kang KS  Han HJ  Lee YS  Lee JH 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2000,62(2):141-146

The mechanisms of ischemic neuronal death have been focused on glutamate receptor activation and subsequent elevation of intracellular Ca2+ concentration. The purpose of this study was to evaluate the effects of dizocilpine, an NMDA receptor antagonist, pretreatment on Fos expression and parvalbumin (PV, calcium binding protein) immunoreactivity in the hippocampus of the mongolian gerbil after global ischemic insults. The number of PV-immunoreactive (PV-ir) neurons in CA1 were significantly decreased from 1 day after cerebral ischemia, while dizocilpine pretreatment completely suppressed the loss of PV-ir neurons in CA1. Dizocilpine pretreatment also protected the structural loss of microtubule-associated protein 2 immunoreactivity in CA1 after ischemic insults. In addition, dizocilpine pretreatment increased Fos expression in both hippocampal CA3 and CA4 after 3 hr ischemic reperfusion as compared to that of the saline pretreated group. Subsequently, the Fos-defined cellular activity of PV-ir neurons was slightly increased by dizocilpine pretreatment in the hippocampal area. This study demonstrated that NMDA receptor mediated calcium influx was associated with the loss of PV-ir neurons in CA1 hippocampal region, and that dizocilpine pretreatment increased Fos expression and the neuronal activity of PV-ir neurons in the non-vulnerable region of hippocampus after cerebral ischemia. Based on this data, we conclude that the protective effect of dizocilpine may be induced by the regulation of calcium overload, or by the upregulation of a neuroregenerative initiator such as Fos protein.  相似文献   

Congenital lymphangiomatosis and an enteric duplication cyst in a young dog     

H. Oui  C. Lamm  S. Stiver  B. Williams  S. Y. Kwon  Y. Bae  S. Jeon  S. Park  J. J. Min  J. Choi 《The Journal of small animal practice》2014,55(7):379-382

A two‐year‐old female poodle with abdominal distention was diagnosed with concurrent enteric duplication cyst and lymphangiomatosis. Both lesions were shown as cystic structures, but some characteristic features of enteric duplication cyst were identified including a thick cyst wall and shared blood supply with the duodenum. Although it was challenging to discriminate between the types of cyst based on diagnostic imaging, this report describes the characteristics of each type of lesion using several different imaging modalities.  相似文献   

Effects of dietary supplementation of lipid‐encapsulated zinc oxide on colibacillosis,growth and intestinal morphology in weaned piglets challenged with enterotoxigenic Escherichia coli     

Chang‐Hoon Kwon  Seung‐ Jae Han  Sung‐Jae Kim  Byung‐Chul Park  Insurk Jang  Jeong‐Hee Han 《Animal Science Journal》2014,85(8):805-813

This study was aimed to evaluate the effect of dietary supplementation of lipid‐encapsulated (coated) zinc oxide ZnO on post‐weaning diarrhea (colibacillosis) in weaned piglets challenged with enterotoxigenic Escherichia coli (ETEC). Thirty‐two 35‐day‐old weaned piglets were orally challenged with 3 × 10¹⁰ colony forming units of ETEC K88 while eight piglets received no challenge (control). Each eight challenged piglets received a diet containing 100 ppm ZnO (low ZnO), 2500 ppm ZnO (high ZnO) or 100 ppm of lipid (10%)‐coated ZnO (coated ZnO) for 7 days; control pigs received the low ZnO diet. Daily gain, goblet cell density in the villi of the duodenum, jejunum and ileum, and villus height in the jejunum and ileum, which decreased due to the challenge, were equally greater in the coated ZnO and high ZnO groups versus low ZnO group. Fecal consistency score, serum interleukin‐8 concentration, subjective score of fecal E. coli shedding, and digesta pH in the stomach, jejunum and ileum, which increased due to the challenge, were equally low in the coated ZnO and high ZnO groups versus low ZnO. Results suggest that a low level of coated ZnO might well substitute for a pharmacological level of native ZnO in dietary supplementation to alleviate colibacillosis of weaned piglets.  相似文献   

Selective catalytic C-H alkylation of alkenes with alcohols     

Lee DH  Kwon KH  Yi CS 《Science (New York, N.Y.)》2011,333(6049):1613-1616

Alkenes and alcohols are among the most abundant and commonly used organic feedstock in industrial processes. We report a selective catalytic alkylation reaction of alkenes with alcohols that forms a carbon-carbon bond between vinyl carbon-hydrogen (C-H) and carbon-hydroxy centers with the concomitant loss of water. The cationic ruthenium complex [(C(6)H(6))(PCy(3))(CO)RuH](+)BF(4)(-) (Cy, cyclohexyl) catalyzes the alkylation in solution within 2 to 8 hours at temperatures ranging from 75° to 110°C and tolerates a broad range of substrate functionality, including amines and carbonyls. Preliminary mechanistic studies are inconsistent with Friedel-Crafts-type electrophilic activation of the alcohols, suggesting instead a vinyl C-H activation pathway with opposite electronic polarization.  相似文献   

C-O bond formation by polyketide synthases     

Kwon HJ  Smith WC  Scharon AJ  Hwang SH  Kurth MJ  Shen B 《Science (New York, N.Y.)》2002,297(5585):1327-1330

Polyketide synthases (PKSs) assemble the polyketide carbon backbone by sequential decarboxylative condensation of acyl coenzyme A (CoA) precursors, and the C-C bond-forming step in this process is catalyzed by the beta-ketoacyl synthase (KS) domain or subunit. Genetic and biochemical characterization of the nonactin biosynthesis gene cluster from Streptomyces griseus revealed two KSs, NonJ and NonK, that are highly homologous to known KSs but catalyze sequential condensation of the acyl CoA substrates by forming C-O rather than C-C bonds. This chemistry can be used in PKS engineering to increase the scope and diversity of polyketide biosynthesis.  相似文献   

Biotransformation of an organochlorine insecticide,endosulfan, by Anabaena species   总被引：2，自引：0，他引：2  

Lee SE  Kim JS  Kennedy IR  Park JW  Kwon GS  Koh SC  Kim JE 《Journal of agricultural and food chemistry》2003,51(5):1336-1340

This study assesses the role of the blue-green algal species present in the soil in the dissipation of endosulfan and its metabolites in the soil environment. Two Anabaena species, Anabaena sp. PCC 7120 and Anabaena flos-aquae, were used in this study. Anabaena sp. PCC 7120 produced three principal biotransformation compounds, chiefly endosulfan diol (endodiol), and minor amounts of endosulfan hydroxyether and endosulfan lactone. Trace amounts of endosulfan sulfate were detected. In comparison, the biotransformation of endosulfan by Anabaena flos-aquae yielded mainly endodiol with minor amounts of endosulfan sulfate. An unknown compound was produced up to 70% from endosulfan spiked in the medium inoculated by A. flos-aquae after 8 days of incubation. Therefore, the endosulfan fate was dependent on the species. Within 1 day of incubation, two Anabaena species produced low amounts of beta-endosulfan after application of alpha-endosulfan. These results suggest the presence of isomerase in the Anabaena species. Further studies using a fermentor to control the medium pH at 7.2 to minimize chemical hydrolysis of endosulfan revealed a major production of endodiol with minor amounts of endosulfan sulfate and the unknown compound. These results showed that the production of the unknown compound might be dependent on the alkaline pH in the medium and that the production of endodiol by A. flos-aquae might be biologically controlled. This study showed that two algal species could contribute in the detoxification pathways of endosulfan in the soil environment.  相似文献   

Use of cDNA-AFLP for transcript profiling in narrow genetic pools; for example, cucumber (Cucumis sativus L.)   总被引：1，自引：1，他引：1  

K. M. Bae    Y. S. Kwon    I. H. Cho    S. I. Yi 《Plant Breeding》2006,125(5):488-492

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Selection and characterization of a 5-methyltryptophan resistant mutant in Zea mays L.     

Kwon Kyoo Kang  Toshiaki Kameya 《Euphytica》1993,69(1-2):95-101

Summary A maize plant resistant to 5-methyltrytophan (5MT) was selected from M₂ seeds (Zea mays L. Danggin, inbred line) originating from ears treated with ethylmethane sulfonate (0.2%) at 6 hr after self-pollination. Genetic analysis of the progeny of plants selected from a medium containing 50 ppm 5MT showed that 5MT resistance was inherited as a single dominant nuclear gene. This resistance was also expressed in callus and seedling. Analysis of the free amino acids in kernels and calli showed that homozygous resistant plants (MR1) contained higher levels of total free amino acids than sensitive plants and calli. In particular, the their kernels the levels of tryptophan, threonine and serine were, respectively, 4.5, 5.9 and 6.3 times higher than those of the sensitive plants. From the results, it may be expected that mutants resistant to amino acid anologs will be useful not only for studying amino acid biosynthesis but also for improving the nutritional quality of maize.Abbreviations EMS Ethylmethane sulfonate - 5MT 5-methyltryptophan - 2,4-D 2-4-dichlorophenoxyacetic acid  相似文献   

Profiling diversity and comparison of Eastern and Western cultivars of Prunus persica based on phenotypic traits     

Jung Hyun Kwon  Ji Hae Jun  Eun Young Nam  Kyeong Ho Chung  Seong Sig Hong  Ik Koo Yoon  Seok Kyu Yun  Yong Bum Kwack 《Euphytica》2015,206(2):401-415

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Preliminary analysis of recombinant β-tubulin of Pseudocohnilembus persalinus (Ciliophora: Scuticociliatida) as a vaccine antigen candidate against scuticociliatosis     

Sung Mi Kim  Eun Hye Lee  Se Ryun Kwon  Sun Joung Lee  Sung Koo Kim  Yoon Kwon Nam  Ki Hong Kim   《Aquaculture (Amsterdam, Netherlands)》2006,260(1-4):21-26

The recombinant β-tubulin of Pseudocohnilembus persalinus was investigated to test whether tubulin could be a suitable antigenic target against scuticociliatosis. The cDNA of P. persalinus β-tubulin has an open reading frame of 1332 bp and had 15 TAA triplets code for glutamine (Q). All 15 TAA/Q triplets of the β-tubulin cDNA were mutated to universal CAA/Q triplets by site-directed mutagenesis and the mutated β-tubulin was expressed in Escherichia coli as a fusion with glutathione S-transferase (GST-BTU). In Western blot analysis, rat sera immunized with recombinant GST-BTU reacted with reduced β-tubulin of P. persalinus. The immunized rat sera showed higher parasiticidal activity than those of control. Ciliates preincubated with heat-inactivated immune sera showed significantly lower proliferation than ciliates preincubated with control sera when exposed to naïve rat sera as a complement source. The present results suggest that the recombinant β-tubulin of scuticociliates may be used as a target antigen for development of vaccine against scuticociliatosis.  相似文献