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1.
PLoS One ; 12(4): e0175500, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28399157

RESUMO

In this paper, based on our previous multi-pattern uniform resource locator (URL) binary-matching algorithm called HEM, we propose an improved multi-pattern matching algorithm called MH that is based on hash tables and binary tables. The MH algorithm can be applied to the fields of network security, data analysis, load balancing, cloud robotic communications, and so on-all of which require string matching from a fixed starting position. Our approach effectively solves the performance problems of the classical multi-pattern matching algorithms. This paper explores ways to improve string matching performance under the HTTP protocol by using a hash method combined with a binary method that transforms the symbol-space matching problem into a digital-space numerical-size comparison and hashing problem. The MH approach has a fast matching speed, requires little memory, performs better than both the classical algorithms and HEM for matching fields in an HTTP stream, and it has great promise for use in real-world applications.


Assuntos
Algoritmos , Internet , Linguagens de Programação
2.
Int J Toxicol ; 33(4): 297-306, 2014 07.
Artigo em Inglês | MEDLINE | ID: mdl-25001243

RESUMO

Lipoxygenase (LOX)-catalyzed cooxidation of the human carcinogen benzidine (BZD) has been shown in in vitro enzyme systems. This study aimed to determine whether BZD could be activated by arachidonate 5-lipoxygenase (ALOX5) in the human tracheobronchial epithelial cells (HBECs) using RNA interference strategy and a 5-LOX-specific inhibitor, AA861. We show that the soybean LOX catalyzed the cooxidation of BZD, generating BZD diimine. Benzidine induced expression of ALOX5 messenger RNA and 5-LOX protein in HBECs, and significantly decreased cell proliferation, but enhanced DNA damage and apoptosis in HBECs which were significantly inhibited by lentiviral-mediated small hairpin RNA-knockdown of ALOX5 and by AA861. Thus, BZD could upregulate the expression of ALOX5 in HBECs, while inhibition of the protein or gene expression or enzyme activity could prevent BZD-induced cytotoxicity and DNA damage in HBECs, which might be caused by the 5-LOX-catalyzed oxidative activation of BZD.


Assuntos
Apoptose/efeitos dos fármacos , Araquidonato 5-Lipoxigenase/metabolismo , Benzidinas/toxicidade , Carcinógenos/toxicidade , Cocarcinogênese/induzido quimicamente , Mucosa Respiratória/efeitos dos fármacos , Ativação Metabólica , Araquidonato 5-Lipoxigenase/química , Araquidonato 5-Lipoxigenase/genética , Benzidinas/metabolismo , Benzoquinonas/farmacologia , Brônquios , Carcinógenos/metabolismo , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Indução Enzimática/efeitos dos fármacos , Células HEK293 , Humanos , Peróxido de Hidrogênio/toxicidade , Lipoxigenase/metabolismo , Inibidores de Lipoxigenase/farmacologia , Oxirredução , Interferência de RNA , RNA Mensageiro/metabolismo , Mucosa Respiratória/citologia , Mucosa Respiratória/metabolismo , Traqueia
3.
Artigo em Chinês | MEDLINE | ID: mdl-19224689

RESUMO

OBJECTIVE: To investigate the effect of intracellular 5-lipoxygenase on oxidation of benzidine in HBE cells and to provide further evidence that lipoxygenase is an alternative pathway for the oxidation of xenobiotics mediated by cytochrome P450. METHODS: Enzyme system test: Soybean lipoxygenase (SLO), substrate (benzidine) and other components reacted in the enzyme system, followed by detection of the reaction products by spectrophotometry. In vitro test: After HBE cells were exposed to benzidine, the protein levels of 5-lipoxygenase in HBE cells were assessed by Western-blot, and the DNA damage by the single cell gel electrophoresis. At last, the effect of the specific inhibitor of 5-lipoxygenase (AA861) on 5-lipoxygenase protein expression and DNA damage in HBE cells were detected. RESULTS: SLO could catalyze the co-oxidation of benzidine to generate benzidine diimine in the presence of hydrogen peroxide. Under optimal condition, numax value of the oxidation of benzidine catalyzed by SLO was 1.42 nmol*min(-1) SLO, and the Km value of benzidine was 1.48 mmol/L. EGCG could inhibit the oxidation of benzidine by SLO. Benzidine could induce 5-lipoxygenase protein expression in HBE cells, but AA861 was invalid. Benzidine caused DNA damage in HBE cells, which could be significantly inhibited by AA861. CONCLUSION: 5-LOX protein expression in HBE cells can be regulated by benzidine, which suggests that the co-oxidation of benzidine by 5-LOX could produce into electrophile that could covalently bind to DNA and induce DNA damage, which could be one of the mechanisms for carcinogenesis of BZD. 5-LOX inhibitor AA861 can inhibit this effect.


Assuntos
Araquidonato 5-Lipoxigenase/metabolismo , Benzidinas/toxicidade , Células Epiteliais/enzimologia , Benzidinas/farmacocinética , Células Cultivadas , Dano ao DNA/efeitos dos fármacos , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/metabolismo , Humanos
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