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991.
Kwang Sik Lee Bo Yeon Kim Young Moo Choo Hyung Joo Yoon Pil Don Kang Soo Dong Woo Hung Dae Sohn Jong Yul Roh Zhong Zheng Gui Yeon Ho Je Byung Rae Jin 《Comparative biochemistry and physiology. Part B, Biochemistry & molecular biology》2009,154(2):188-194
Proteolytic enzymes are involved in insect molting and metamorphosis, and play a vital role in the programmed cell death of obsolete organs. Here we show the expression profile of cathepsin B in the fat body of the silkworm Bombyx mori during development. We also compare the expression profiles of B. mori cathepsins B (BmCatB) and D (BmCatD) during normal development and after RNA interference (RNAi)-mediated inhibition. BmCatB is induced by 20-OH-ecdysone, and is expressed in the fat body of B. mori during molting and the larval–pupal and pupal–adult transformations, where its expression leads to programmed cell death. In particular, BmCatB is highly expressed in the fat body of B. mori during the larval–pupal transformation, and BmCatB RNAi treatment resulted in an arrest of the larval–pupal transformation. RNAi-mediated BmCatB knockdown sustained the expression of BmCatD during the larval–pupal transformation. On the other hand, when BmCatD was inhibited via RNAi, the expression of BmCatB was upregulated. Based on these results, we conclude that BmCatB is involved in the programmed cell death of the fat body during B. mori metamorphosis, and that BmCatB and BmCatD contribute to B. mori metamorphosis. 相似文献
992.
993.
Je Chul Lee Dong Sun Kim Dong Chan Moon Jung-Hwa Lee Mi Jin Kim Su Man Lee Yong Seok Lee Se-Won Kang Eun Jung Lee Sang Sun Kang Eunpyo Lee Sung Hee Hyun 《Journal of microbiology (Seoul, Korea)》2009,47(5):641-645
Nuclear targeting of bacterial proteins is an emerging pathogenic mechanism whereby bacterial proteins can interact with nuclear molecules and alter the physiology of host cells. The fully sequenced bacterial genome can predict proteins that target the nuclei of host cells based on the presence of nuclear localization signal (NLS). In the present study, we predicted bacterial proteins with the NLS sequences from Klebsiella pneumoniae by bioinformatic analysis, and 13 proteins were identified as carrying putative NLS sequences. Among them, HsdM, a subunit of KpnAl that is a type I restriction-modification system found in K. pneumoniae, was selected for the experimental proof of nuclear targeting in host cells. HsdM carried the NLS sequences, 7KKAKAKK13, in the N-terminus. A transient expression of HsdM-EGFP in COS-1 cells exhibited exclusively a nuclear localization of the fusion proteins, whereas the fusion proteins of HsdM with substitutions in residues lysine to alanine in the NLS sequences, 7AAAKAAA13, were localized in the cytoplasm. HsdM was co-localized with importin o in the nuclei of host cells. Recombinant HsdM alone methylated the eukaryotic DNA in vitro assay. Although HsdM tested in this study has not been considered to be a virulence factor, the prediction of NLS motifs from the full sequenced genome of bacteria extends our knowledge of functional genomics to understand subcellular targeting of bacterial proteins. 相似文献
994.
Hee Young Kang Jungmin Kim Sung Yong Seol Yoo Chul Lee Je Chul Lee Dong Taek Cho 《Journal of microbiology (Seoul, Korea)》2009,47(1):68-75
In this study, we identified extended-spectrum β-lactamase (ESBL) and plasmid-mediated AmpC β-lactamase which were associated
with 16S rRNA methylase gene on the conjugative plasmid. Among 82 clinical isolates of Enterobacteriaceae that carry 16S rRNA methylase gene (64 strains, armA, and 18 strains, rmtB), bla
SHV-12 was detected either alone or combined with bla
DHA-1, bla
CTX-M-3, and bla
CTX-M-14 in 30 strains carrying armA and 6 strains carrying rmtB. The bla
CTX-M-3 was detected in 13 of 64 strains carrying armA but no strains carrying rmtB. Whereas bla
CTX-M-14 was detected in 15 of 18 strains carrying rmtB but only 2 of 64 strains carrying armA. Overall, bla
SHV-12 and bla
CTX-M-14 was the most common ESBL gene which was associated with armA and rmtB, respectively. In addition, we found that bla
CTX-M-3 localized with armA on the same IncL/M plasmid and bla
CTX-M-14 localized with rmtB on the same IncA/C plasmid. Restriction fragment length polymorphism of conjugative plasmids and pulsed-field gel electrophoresis
of genomic DNAs revealed that intercellular horizontal transfer of conjugative plasmid and clonal transmission have been occurred
at the same time. 相似文献
995.
Al-Aboudi A Odeh H Khalid A Naz Q Choudhary MI 《Journal of enzyme inhibition and medicinal chemistry》2009,24(2):553-558
Testosterone and ten of its metabolites were examined as inhibitors of butyrylcholinesterase. A significant enzyme inhibition activity (IC(50) = 1.55 microM) was observed for androst-4-en-3,7-dione. The kinetic parameters of butyrylcholinesterase inhibition were determined and molecular docking was carried out in order to develop a better understanding of the inhibitor-enzyme interactions. The results showed that the inhibition was non-competitive, stabilized mainly by hydrogen bonds and hydrophobic interactions between the inhibitor and butyrylcholinesterase. 相似文献
996.
Jaroslava Folbergrová Pavel Ješina Renata Haugvicová Václav Lisý Josef Houštěk 《Neurochemistry international》2010,56(3):394-403
Our previous work demonstrated the marked decrease of mitochondrial complex I activity in the cerebral cortex of immature rats during the acute phase of seizures induced by bilateral intracerebroventricular infusion of dl-homocysteic acid (600 nmol/side) and at short time following these seizures. The present study demonstrates that the marked decrease (~60%) of mitochondrial complex I activity persists during the long periods of survival, up to 5 weeks, following these seizures, i.e. periods corresponding to the development of spontaneous seizures (epileptogenesis) in this model of seizures. The decrease was selective for complex I and it was not associated with changes in the size of the assembled complex I or with changes in mitochondrial content of complex I. Inhibition of complex I was accompanied by a parallel, up to 5 weeks lasting significant increase (15–30%) of three independent mitochondrial markers of oxidative damage, 3-nitrotyrosine, 4-hydroxynonenal and protein carbonyls. This suggests that oxidative modification may be most likely responsible for the sustained deficiency of complex I activity although potential role of other factors cannot be excluded. Pronounced inhibition of complex I was not accompanied by impaired ATP production, apparently due to excess capacity of complex I documented by energy thresholds. The decrease of complex I activity was substantially reduced by treatment with selected free radical scavengers. It could also be attenuated by pretreatment with (S)-3,4-DCPG (an agonist for subtype 8 of group III metabotropic glutamate receptors) which had also a partial antiepileptogenic effect.It can be assumed that the persisting inhibition of complex I may lead to the enhanced production of reactive oxygen and/or nitrogen species, contributing not only to neuronal injury demonstrated in this model of seizures but also to epileptogenesis. 相似文献
997.
998.
The P2X4 receptor (P2X4R) is a member of a family of ATP-gated cation channels that are composed of three subunits. Each subunit
has two transmembrane (TM) domains linked by a large extracellular loop and intracellularly located N- and C-termini. The
receptors are expressed in excitable and non-excitable cells and have been implicated in the modulation of membrane excitability,
calcium signaling, neurotransmitter and hormone release, and pain physiology. P2X4Rs activate rapidly and desensitize within
the seconds of agonist application, both with the rates dependent on ATP concentrations, and deactivate rapidly and independently
of ATP concentration. Disruption of conserved cysteine ectodomain residues affects ATP binding and gating. Several ectodomain
residues of P2X4R were identified as critical for ATP binding, including K67, K313, and R295. Ectodomain residues also account
for the allosteric regulation of P2X4R; H140 is responsible for copper binding and H286 regulates receptor functions with
protons. Ivermectin sensitized receptors, amplified the current amplitude, and slowed receptor deactivation by binding in
the TM region. Scanning mutagenesis of TMs revealed the helical topology of both domains, and suggested that receptor function
is critically dependent on the conserved Y42 residue. In this brief article, we summarize this study and re-interpret it using
a model based on crystallization of the zebrafish P2X4.1 receptor. 相似文献
999.
Several mechanisms have been proposed to account for the marked increase in severity of human infections with avian compared to human influenza strains, including increased cytokine expression, poor immune response, and differences in target cell receptor affinity. Here, the potential effect of target cell tropism on disease severity is studied using a mathematical model for in-host influenza viral infection in a cell population consisting of two different cell types. The two cell types differ only in their susceptibility to infection and rate of virus production. We show the existence of a parameter regime which is characterized by high viral loads sustained long after the onset of infection. This finding suggests that differences in cell tropism between influenza strains could be sufficient to cause significant differences in viral titer profiles, similar to those observed in infections with certain strains of influenza A virus. The two target cell mathematical model offers good agreement with experimental data from severe influenza infections, as does the usual, single target cell model albeit with biologically unrealistic parameters. Both models predict that while neuraminidase inhibitors and adamantanes are only effective when administered early to treat an uncomplicated seasonal infection, they can be effective against more severe influenza infections even when administered late. 相似文献
1000.
Surender Khurana Swati Verma Nitin Verma Corey J. Crevar Donald M. Carter Jody Manischewitz Lisa R. King Ted M. Ross Hana Golding 《PloS one》2010,5(7)