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31.
Polymorphisms of interferon-inducible genes OAS-1 and MxA associated with SARS in the Vietnamese population 总被引:9,自引:0,他引:9
Hamano E Hijikata M Itoyama S Quy T Phi NC Long HT Ha LD Ban VV Matsushita I Yanai H Kirikae F Kirikae T Kuratsuji T Sasazuki T Keicho N 《Biochemical and biophysical research communications》2005,329(4):1234-1239
We hypothesized that host antiviral genes induced by type I interferons might affect the natural course of severe acute respiratory syndrome (SARS). We analyzed single nucleotide polymorphisms (SNPs) of 2',5'-oligoadenylate synthetase 1 (OAS-1), myxovirus resistance-A (MxA), and double-stranded RNA-dependent protein kinase in 44 Vietnamese SARS patients with 103 controls. The G-allele of non-synonymous A/G SNP in exon 3 of OAS-1 gene showed association with SARS (p=0.0090). The G-allele in exon 3 of OAS-1 and the one in exon 6 were in strong linkage disequilibrium and both of them were associated with SARS infection. The GG genotype and G-allele of G/T SNP at position -88 in the MxA gene promoter were found more frequently in hypoxemic group than in non-hypoxemic group of SARS (p=0.0195). Our findings suggest that polymorphisms of two IFN-inducible genes OAS-1 and MxA might affect susceptibility to the disease and progression of SARS at each level. 相似文献
32.
Tran TT Mamo G Búxo L Le NN Gaber Y Mattiasson B Hatti-Kaul R 《Enzyme and microbial technology》2011,49(2):177-182
Site-directed mutagenesis of a thermostable alkaline phytase from Bacillus sp. MD2 was performed with an aim to increase its specific activity and activity and stability in an acidic environment. The mutation sites are distributed on the catalytic surface of the enzyme (P257R, E180N, E229V and S283R) and in the active site (K77R, K179R and E227S). Selection of the residues was based on the idea that acid active phytases are more positively charged around their catalytic surfaces. Thus, a decrease in the content of negatively charged residues or an increase in the positive charges in the catalytic region of an alkaline phytase was assumed to influence the enzyme activity and stability at low pH. Moreover, widening of the substrate-binding pocket is expected to improve the hydrolysis of substrates that are not efficiently hydrolysed by wild type alkaline phytase. Analysis of the phytase variants revealed that E229V and S283R mutants increased the specific activity by about 19% and 13%, respectively. Mutation of the active site residues K77R and K179R led to severe reduction in the specific activity of the enzyme. Analysis of the phytase mutant-phytate complexes revealed increase in hydrogen bonding between the enzyme and the substrate, which might retard the release of the product, resulting in decreased activity. On the other hand, the double mutant (K77R-K179R) phytase showed higher stability at low pH (pH 2.6-3.0). The E227S variant was optimally active at pH 5.5 (in contrast to the wild type enzyme that had an optimum pH of 6) and it exhibited higher stability in acidic condition. This mutant phytase, displayed over 80% of its initial activity after 3 h incubation at pH 2.6 while the wild type phytase retained only about 40% of its original activity. Moreover, the relative activity of this mutant phytase on calcium phytate, sodium pyrophosphate and p-nitro phenyl phosphate was higher than that of the wild type phytase. 相似文献
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Sozaburo Ihara Yukiko Miyamoto Christine H. Y. Le Vivien N. Tran Elaine M. Hanson Marvin Fischer Kurt Hanevik Lars Eckmann 《PLoS neglected tropical diseases》2022,16(4)
Giardia lamblia is a leading protozoal cause of diarrheal disease worldwide. Infection is associated with abdominal pain, malabsorption and weight loss, and protracted post-infectious syndromes. A human vaccine is not available against G. lamblia. Prior studies with human and murine immune sera have identified several parasite antigens, including surface proteins and metabolic enzymes with intracellular functions. While surface proteins have demonstrated vaccine potential, they can exhibit significant variation between G. lamblia strains. By comparison, metabolic enzymes show greater conservation but their vaccine potential has not been established. To determine whether such proteins can serve as vaccine candidates, we focused on two enzymes, α-enolase (ENO) and ornithine carbamoyl transferase (OCT), which are involved in glycolysis and arginine metabolism, respectively. We show in a cohort of patients with confirmed giardiasis that both enzymes are immunogenic. Intranasal immunization with either enzyme antigen in mice induced strong systemic IgG1 and IgG2b responses and modest mucosal IgA responses, and a marked 100- to 1,000-fold reduction in peak trophozoite load upon oral G. lamblia challenge. ENO immunization also reduced the extent and duration of cyst excretion. Examination of 44 cytokines showed only minimal intestinal changes in immunized mice, although a modest increase of CCL22 was observed in ENO-immunized mice. Spectral flow cytometry revealed increased numbers and activation state of CD4 T cells in the small intestine and an increase in α4β7-expressing CD4 T cells in mesenteric lymph nodes of ENO-immunized mice. Consistent with a key role of CD4 T cells, immunization of CD4-deficient and Rag-2 deficient mice failed to induce protection, whereas mice lacking IgA were fully protected by immunization, indicating that immunity was CD4 T cell-dependent but IgA-independent. These results demonstrate that conserved metabolic enzymes can be effective vaccine antigens for protection against G. lamblia infection, thereby expanding the repertoire of candidate antigens beyond primary surface proteins. 相似文献
35.
Natalie J. Beveridge Paul A. Tooney Adam P. Carroll Nham Tran Murray J. Cairns 《Cellular signalling》2009,21(12):1837-1845
Whole-genome microRNA and gene expression analyses were used to monitor changes during retinoic acid induced differentiation of neuroblasts in vitro. Interestingly, the entire miR-17 family was over-represented among the down-regulated miRNA. The implications of these changes are considerable, as target gene prediction suggests that the miR-17 family is involved in the regulation of the mitogen-activated protein kinase (MAPK) signaling pathway, synaptic plasticity and other markers of neuronal differentiation. Significantly, many of the target responses predicted by changes in miRNA expression were supported by the observed changes in gene expression. As expected, markers of neuronal differentiation such as anti-apoptotic protein B-cell lymphoma 2 (BCL2), myocyte enhancer factor-2D (MEF2D) and zipper protein kinase (MAP3K12; aka ZPK/MUK/DLK) were each up-regulated in response to differentiation. The expression of these genes was also reduced in response to miR-17 and miR-20a transfection, and more specifically they were also shown to contain functional miRNA recognition elements for members of the miR-17 family by reporter gene assay. This suggests that the miR-17 family have an integral role in fine-tuning the pathways involved in the regulation of neuronal differentiation. 相似文献
36.
ATP is an important modulator of gating in type 1 ryanodine receptor (RyR1), also known as a Ca2+ release channel in skeletal muscle cells. The activating effect of ATP on this channel is achieved by directly binding to one or more sites on the RyR1 protein. However, the number and location of these sites have yet to be determined. To identify the ATP-binding regions within RyR1 we used 2N3ATP-2′,3′-Biotin-LC-Hydrazone (BioATP-HDZ), a photo-reactive ATP analog to covalently label the channel. We found that BioATP-HDZ binds RyR1 specifically with an IC50 = 0.6±0.2 mM, comparable with the reported EC50 for activation of RyR1 with ATP. Controlled proteolysis of labeled RyR1 followed by sequence analysis revealed three fragments with apparent molecular masses of 95, 45 and 70 kDa that were crosslinked by BioATP-HDZ and identified as RyR1 sequences. Our analysis identified four glycine-rich consensus motifs that can potentially constitute ATP-binding sites and are located within the N-terminal 95-kDa fragment. These putative nucleotide-binding sequences include amino acids 699–704, 701–706, 1081–1084 and 1195–1200, which are conserved among the three RyR isoforms. Located next to the N-terminal disease hotspot region in RyR1, these sequences may communicate the effects of ATP-binding to channel function by tuning conformational motions within the neighboring cytoplasmic regulatory domains. Two other labeled fragments lack ATP-binding consensus motifs and may form non-canonical ATP-binding sites. Based on domain topology in the 3D structure of RyR1 it is also conceivable that the identified ATP-binding regions, despite their wide separation in the primary sequence, may actually constitute the same non-contiguous ATP-binding pocket within the channel tetramer. 相似文献
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38.
Hien Van Doan Seyed Hossein Hoseinifar Wanaporn Tapingkae Mintra Seel-audom Sanchai Jaturasitha Mahmoud A. O. Dawood Sutee Wongmaneeprateep Tran Thi Nang Thu Maria ngeles Esteban 《Probiotics and antimicrobial proteins》2020,12(2):400-411
The present work, herein, studied the effects of corncob-derived xylooligosaccharides (CDXOS) and Lactobacillus plantarum CR1T5 (LP) integrated into fish d 相似文献
39.
A new temperate wood bamboo endemic to Vietnam is described and illustrated as Chimonocalamus bidoupensis N.H.Nghia & V.T.Tran. The new species is similar to C. baviensis in general appearance, but differs by its densely ciliate culms, culm sheaths that are concave at the apex with dense, white hairs on the abaxial surface of the sheath, and perfect florets 7–8 mm long. 相似文献
40.