摘要:
Heme proteins perform various biological functions ranging from electron transfer, oxygen binding and transport, catalysis, to signaling. Although adopting proper native states is very important for these functions, progresses in representative heme proteins, including cytochrome c (cyt c), cytochrome b5 (cyt b5), myoglobin (Mb), neuroglobin (Ngb), cytochrome P450 (CYP) and heme-based sensor proteins such as CO sensor CooA, showed that various native functions, or new functions evolved, are also closely associated with non-native states. The structure and function relationship of heme proteins in non-native states is thus as important as that in native states for elucidating the precise roles of heme proteins in biological systems.
期刊:
Journal of AOAC International,2013年96(4):897-901 ISSN:1060-3271
通讯作者:
Peng, Tao
作者机构:
[Nie, Chang-Ming; Xie, Jie; Zhang, Qing-Jie] Univ South China, Dept Chem & Chem Engn, Hengyang 421001, Hunan, Peoples R China.;[Peng, Tao; Chen, Dong-Dong] Chinese Acad Inspect & Quarantine, Agroprod Safety Res Ctr, Beijing 100123, Peoples R China.;[Wang, Xiong] Clover Technol Grp Ltd, Beijing 100044, Peoples R China.;[Wang, Guo-Min] Chongqing Entry Exit Inspect & Quarantine Bur, Chongqing 400020, Peoples R China.
通讯机构:
[Peng, Tao] C;Chinese Acad Inspect & Quarantine, Agroprod Safety Res Ctr, Beijing 100123, Peoples R China.
摘要:
A method based on HPLC with UV detection was developed for the quantitative determination of chloramphenicol (CAP) residues in aquatic products. The samples were extracted with ethyl acetate–ammonium hydroxide (98 + 2, v/v), followed by a cleanup step using an immunoaffinity column. The analytes were determined by HPLC-UV. Optimal conditions for the extraction and cleanup procedures are described. The linear regression equation was y = 91.47x – 8.60 with R2 = 0.9998 (y = peak area and x = CAP concentration) and showed a good reproducibility. The LOQ was 0.25 μg/kg for determining CAP spiked in the aquatic products. The mean recoveries of CAP from fish and shrimp samples fortified at 0.25–1.0 μg/kg were 88.7–93.1 and 92.0–97.3%, respectively; the repeatability RSDs were less than 8.1%. It was concluded that the method is simple, highly sensitive, and low cost for quantitatively measuring CAP residues in aquatic products. Analyte identification was confirmed by HPLC/MS/MS analysis.
期刊:
Lipids in Health and Disease,2012年11(1):1-9 ISSN:1476-511X
通讯作者:
Fu, Mingde
作者机构:
[Tian, Li; Long, Shiyin; Liu, Yinghui; Fu, Mingde] Sichuan Univ, W China Hosp, Lab Endocrinol & Metab, Chengdu 610041, Sichuan, Peoples R China.;[Tian, Li; Liu, Yinghui; Fu, Mingde] Sichuan Univ, State Key Lab Biotherapy, Chengdu 610041, Sichuan, Peoples R China.;[Long, Shiyin] Univ S China, Dept Biochem & Mol Biol, Hengyang, Hunan, Peoples R China.;[Zeng, Zhi; Chen, Yucheng; Li, Chuanwei] Sichuan Univ, W China Hosp, Cardiovasc Dept, Chengdu 610041, Sichuan, Peoples R China.
通讯机构:
[Fu, Mingde] S;Sichuan Univ, W China Hosp, Lab Endocrinol & Metab, Chengdu 610041, Sichuan, Peoples R China.
关键词:
Coronary heart disease;High density lipoprotein subclasses;Diabetic mellitus;Fasting plasma glucose
摘要:
A higher prevalence of coronary heart disease (CHD) in people with diabetes. We investigated the high-density lipoprotein (HDL) subclass profiles and alterations of particle size in CHD patients with diabetes or without diabetes. Plasma HDL subclasses were quantified in CHD by 1-dimensional gel electrophoresis coupled with immunodetection. Although the particle size of HDL tend to small, the mean levels of low density lipoprotein cholesterol(LDL-C) and total cholesterol (TC) have achieved normal or desirable for CHD patients with or without diabetes who administered statins therapy. Fasting plasma glucose (FPG), triglyceride (TG), TC, LDL-C concentrations, and HDL3 (HDL3b and 3a) contents along with Gensini Score were significantly higher; but those of HDL-C, HDL2b+preβ2, and HDL2a were significantly lower in CHD patients with diabetes versus CHD patients without diabetes; The preβ1-HDL contents did not differ significantly between these groups. Multivariate regression analysis revealed that Gensini Score was significantly and independently predicted by HDL2a, and HDL2b+preβ2. The abnormality of HDL subpopulations distribution and particle size may contribute to CHD risk in diabetes patients. The HDL subclasses distribution may help in severity of coronary artery and risk stratification, especially in CHD patients with therapeutic LDL, TG and HDL levels.
通讯机构:
[He, Shuya] U;Univ S China, Dept Biochem & Mol Biol, Hengyang 421001, Peoples R China.
关键词:
small interfering RNA;hypoxia-inducible factor-1 alpha;multidrug resistance-1;multidrug resistance-associated protein
摘要:
This study aimed to investigate the effects of knocking down hypoxia-inducible factor-1α (HIF-1α) through RNA interference on hypoxia-induced increases in drug resistance in A549/CDDP cells, and to study the underlying mechanisms. A small interfering RNA (siRNA) eukaryotic expression vector targeting HIF-1α was constructed and transfected into A549/CDDP cells treated with hypoxia. The mRNA and protein levels of HIF-1α, multidrug resistance-1 (MDR1), and multidrug resistance-associated protein (MRP) were determined by reverse transcription polymerase chain reaction (RT-PCR) and immunocytochemistry. Cell viability following treatment with cisplatin was determined by MTT assay. Hypoxia increased the resistance of A549/CDDP cells to cisplatin and this effect was reversed by the siRNA inhibition of HIF-1α expression. Expression of HIF-1α siRNA also downregulated HIF-1α, MDR1 and MRP mRNA, and protein expression in A549/CDDP cells treated with hypoxia (p<0.05). Hypoxia-induced resistance of A549/CDDP cells to cisplatin is reversed by the siRNA inhibition of HIF-1α expression. This effect may be mediated by a decreased expression of MDR1 and MRP.
摘要:
As a novel kind of nanomaterial with wide potential applications, the adverse effects of carbon nanotubes (CNTs) have recently received significant attention after respiratory exposure. In this study, single-wall carbon nanotubes (SWCNTs) containing different metal contents were intratracheally instilled into lungs of spontaneously hypertensive rats. Pulmonary and cardiovascular system alterations were evaluated at 24 and 72 h post-instillation. Biomarkers of inflammation, oxidative stress and cell damage in the bronchoalveolar lavage fluid (BALF) were increased significantly 24 h post-exposure of SWCNTs. The increased endothelin-1 levels in BALF and plasma and angiotensin I-converting enzyme in plasma suggested endothelial dysfunction in the pulmonary circulation and peripheral vascular thrombosis. These findings suggest that respiratory exposure to SWCNTs can induce acute pulmonary and cardiovascular responses and individuals with existing cardiovascular diseases are very susceptible to SWCNTs exposure. The co-existence of metal residues in SWCNTs can aggravate the adverse effects.
作者机构:
[Li, Jie; Huang, Chunlin] Univ S China, Sch Pharm & Life Sci, Dept Biochem & Mol Biol, Hengyang 421001, Peoples R China.;[Guo, Bin; Wang, Xiaoying; Zhu, Weitao; Chen, Bo; Yao, Shouzhuo] Hunan Normal Univ, Minist Educ China, Key Lab Chem Biol & Tradit Chinese Med Res, Changsha 410081, Hunan, Peoples R China.;[Ouyang, Shan] Shenzhen Entry Exit Inspect & Quarantine Bur Peop, Food Inspect & Quarantine Ctr, Shenzhen 518067, Peoples R China.
通讯机构:
[Guo, Bin] H;Hunan Normal Univ, Minist Educ China, Key Lab Chem Biol & Tradit Chinese Med Res, Changsha 410081, Hunan, Peoples R China.
关键词:
Animal tissues;Dispersive solid-phase extraction;Multi-residue;Semi-targeted screening;Sulfonamides;Triple-quadrupole linear ion trap mass spectrometer
摘要:
A generic and efficient homolog-targeted approach was used to expand screening and detection of target class of sulfonamides and structural analogs, based on a fast single-tube extraction/partitioning-multifunction adsorption cleanup (SEP/MAC) for class-specific fragmentation-dependent acquisition with a liquid chromatography-hybrid triple-quadrupole linear ion trap mass spectrometer (LC-QqLIT). By combining the two-stage process conducted in a single tube as one-pot protocol, the straightforward SEP/MAC procedure was optimized to offer clean extracts with reasonable recovery (71-109% with RSDs < 20%) and decreased matrix interferences (-9 to 19%) of multiresidual sulfonamide extraction from different tissue samples. The novel use of neutral loss scan of 66 Da (NLS) or precursor ion scanning of m/z 108 (PreS) in positive ion mode was found to achieve more comprehensive coverage of protonated molecular ions of a wide array of sulfonamides including N-4-acetyl and hydroxylamine metabolites plus their possible dimers. Moreover, the PreS-triggered automatically enhanced product ion spectral acquisition enabled simultaneous screening, profiling and confirmation of an unlimited number of analytes belonging to the sulfonamide class within a single analysis. The validation and application results of the generic SEP/MAC-based LC-QqLIT strategy consistently demonstrated favorable performances with acceptable accuracy (67-116%), precision (RSDs < 25%), and sensitivity (LOQs <= 7.5 ng g(-1)) to meet the acceptance criteria for all the sulfonamide-tissue combinations. Thus, the integration of the matrix-independent SEP/MAC procedure and the multiparameter matching algorithm with the unit-resolution LC-QqLIT instrument can serve as a valuable semi-targeted discovery strategy for rapid screening and reliable quantitative/confirmatory analysis of real samples. (C) 2012 Elsevier B.V. All rights reserved.
摘要:
Bovine liver cytochrome b 5 (cyt b 5), with heme bound noncovalently, has been converted into a cyt c-like protein (cyt b 5 N57C) by constructing a thioether linkage between the heme and the engineered cysteine residue. With no X-ray or NMR structure available, we herein performed a molecular modeling study of cyt b 5 N57C. On the other hand, using amino acid sequence information for a newly discovered member of the cyt b 5 family, domestic silkworm cyt b 5 (DS cyt b 5), we predicted the protein structure by homology modeling in combination with MD simulation. The modeling structure shows that both Cys57 in cyt b 5 N57C, and Cys56, a naturally occurring cysteine in DS cyt b 5, have suitable orientations to form a thioether bond with the heme 4-vinyl group, as the heme is in orientation A. In addition to providing structural information that was not previously obtained experimentally, these modeling studies provide insight into the formation of cyt c-like thioether linkages in cytochromes, and suggest that c-type cyt b 5 maturation involves a b-type intermediate.
作者:
Ling, H. -y.;Hu, B.;Hu, X. -b.;Zhong, J.;Feng, S. -d.;...
期刊:
Experimental and Clinical Endocrinology and Diabetes,2012年120(9):553-559 ISSN:0947-7349
通讯作者:
Liao, D. -f.
作者机构:
[Ling, H. -y.; Hu, B.] Univ S China, Sch Med, Dept Physiol, Hengyang, Peoples R China.;[Liao, D. -f.] Hunan Univ Chinese Med, State Key Lab Chinese Med Powder & Med Innovat Hu, Div Stem Cell Regulat & Applicat, Changsha 410208, Hunan, Peoples R China.;[Ling, H. -y.] Univ S China, Ctr Basic Med Postdoctoral Studies, Hengyang, Peoples R China.;[Hu, X. -b.] Univ S China, Sch Life Sci & Technol, Dept Biochem & Mol Biol, Hengyang, Peoples R China.;[Wen, G. -b.; Zhong, J.] Univ S China, Affiliated Hosp 1, Inst Clin Res, Hengyang, Peoples R China.
通讯机构:
[Liao, D. -f.] H;Hunan Univ Chinese Med, State Key Lab Chinese Med Powder & Med Innovat Hu, Div Stem Cell Regulat & Applicat, Changsha 410208, Hunan, Peoples R China.
摘要:
A novel small molecule probe, aptamer beacon (AB), was introduced for adenosine (Ade) recognition and quantitative analysis. The Ade aptamer was engineered into an aptamer beacon by adding a gold nanoparticle-modified nucleotide sequence which is complementary to aptamer sequence (FDNA) at the 3'-end of FDNA. The fluorescence signal "turning on" was observed when AB was bound to Ade, which is attributed to a significant conformational change in AB from a FDNA/QDNA duplex to a FDNA-Ade complex. The Ade measurement was carried out in 20 mmol L-1 Tris-HCl buffer solution of pH 7.4, Delta F signal linearly correlated with the concentration of Ade over the range of 2.0 x 10(-8) to 1.8 x 10(-6) mol L-1. The limit of detection (LOD) for Ade is 6.0 x 10(-9) mol L-1 with relative standard deviations (R.S.D) of 3.64-5.36%, and the recoveries were 98.6%, 100%, 102% (n = 6), respectively. The present method has been successfully applied to determine Ade in human urine samples, and the obtained results were in good agreement with those obtained by the HPLC method. Our investigation shows that the unique properties of the AB could provide a promising potential for small molecules detection, and be benefit to extend the application of aptamer beacon technique. (C) 2012 Elsevier B.V. All rights reserved.
摘要:
The biological toxicity of uranyl ion (UO 2+2 ) lies in interacting with proteins and disrupting their native functions. The structural and functional consequences of UO 2+2 interacting with cytochrome b 5 (cyt b 5), a small membrane heme protein, and its heme axial ligand His39Ser variant, cyt b 5 H39S, were investigated both experimentally and theoretically. In experiments, although cyt b 5 was only slightly affected, UO 2+2 binding to cyt b 5 H39S with a K D of 2.5 μM resulted in obvious alteration of the heme active site, and led to a decrease in peroxidase activity. Theoretically, molecular simulation proposed a uranyl ion binding site for cyt b 5 at surface residues of Glu37 and Glu43, revealing both coordination and hydrogen bonding interactions. The information gained in this study provides insights into the mechanism of uranyl toxicity toward membrane protein at an atomic level. Impacts of uranyl ion on the structure and function of cytochrome b5 H39S variant