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Biomedical subjects

Yong Jiang

Publications and source records attributed to Yong Jiang.

At least 109 records · Page 6Linked to original sources
PubMed2004

[Research advances in wheat (Triticum aestivum) allelopathy].

Wheat (Triticum aestivum) is the main food crop in the world, and plays an important role in agricultural production. In order to enhance wheat yield, herbicides and germicides were intensively applied and made negative effects on the environment. Wheat possesses allelopathic potential for weed suppression and disease control through the release of secondary metabolites from its living plants or residues, which could avoid the environment pollution brought by herbicides and germicides. This paper reviewed the research advances in wheat allelopathy. Hydroxamic acids and phenolic acids are the predominant allelochemicals frequently reported which could produce plant natural defense against weed, pest and disease. The allelopathic activity of allelochemicals is determined not only by the allelochemicals, but also by the factors of inheritance, environment and biology. The retention, transportation and transformation processes of allelochemicals, and the relationship between wheat allelopathy and soil biota and its mechanism were seldom studied and still needed to be researched profoundly. Utilizing wheat allelopathy in plant protection, environment protection and crop breeding would improve the stress-resistance, yield and quality of wheat in agricultural production.

Coumaric Acids↗
PubMed2004

[A case-control study on the risk factors of Alzheimer's disease in military elderly men].

OBJECTIVE: To investigate the risk of Alzheimer's disease (AD) associated with life style, early exposure to magnetic fields, family history of dementia and other risk factors. METHODS: We conducted a case-control study among the inpatients of Chinese PLA General Hospital in 2000 - 2003. Sixty-two AD cases and 124 controls were selected and matched for age. Univariate and multivariate analyses were conducted using logistic regression model. RESULTS: All subjects were males aged 66 to 102. In univariate analysis, lack of social activities, more physical exercises, early exposure to magnetic fields, suffering from negative life events and family history of dementia were statistically different between two groups (P < 0.05). Multivariate analysis showed that after adjusting for potential confounders, suffering from negative life events, family histories of dementia increased the risk of AD with odds ratio (OR) and 95% confidence interval (CI) 3.27 (1.53 - 6.97) and 5.78 (1.39 - 24.10). Early exposure to magnetic fields seemed a possible risk factor for AD, with OR (95% CI) 2.49 (0.96 - 6.45). The amount of social activities, cigarette smoking and history of cancers were negatively correlated with AD and their ORs (95% CI) were 0.81 (0.72 - 0.92), 0.46 (0.21 - 1.00) and 0.31 (0.12 - 0.82) respectively. CONCLUSION: The study demonstrated that suffering from negative life events and family history of dementia were risk factors for AD, and the early exposure to magnetic fields might also play a role.

Aged↗
PubMed2004

[Structure, function and modulation of actin-related protein 2/3 complex].

Microfilaments, composed of global actins, involve in many important physiological activities, such as the maintenance of cell shape and cell migration. Actin-related protein 2/3 ( Arp2/3) complex plays a key role in microfilament formation. Actin-related protein 2/3 ( Arp2/3 ) complex which is composed of seven different subunits is subjected to the modulation of many nucleation promoting factors (NPFs) and cooperates with these factors to regulate the actin nucleation. The study of the structure, function and modulation of Arp2/3 complex is important in understanding the mechanism of the formation of microfilament and the interaction between cytoskeleton and signaling molecules.

Actin Cytoskeleton↗
PubMed2003

A multifunctional plasmid-encoded replication initiation protein both recruits and positions an active helicase at the replication origin.

The DnaA replication initiation protein has been shown to be essential for DNA strand opening at the AT-rich region of the replication origin of the Escherichia coli chromosome as well as serving to recruit and position the DnaB replicative helicase at this open region. Homologues of the dnaA gene of E. coli have been found in most bacterial species, and the DnaA protein has been shown to be required for the initiation of replication of both chromosomal and plasmid DNA. For several plasmid elements it has been found that a plasmid-encoded initiation protein is required along with the DnaA protein to bring about opening of the AT-rich region at the replication origin. The broad host range plasmid RK2 encodes two forms of its replication initiation protein (TrfA-33 and TrfA-44) that differ by an additional 98 aa at the N terminus of the larger (TrfA-44) form. Both forms initiate replication of RK2 in E. coli in vitro by a DnaA-dependent mechanism. However, as shown in this study, TrfA-44 specifically interacts with the DnaB replicative helicase of Pseudomonas putida and Pseudomonas aeruginosa and initiates the formation of a prepriming open complex in the absence of DnaA protein. Thus, the TrfA-44 initiation protein has the multifunctional properties of recruiting and positioning an active form of the DnaB helicase at the RK2 replication origin by a DnaA-independent process. This unique property for a replication initiation protein undoubtedly plays an important role in extending the host range of the RK2 antibiotic resistance plasmid.

Bacterial Proteins↗
PubMed2003

The evolution of vertebrate blood coagulation as viewed from a comparison of puffer fish and sea squirt genomes.

The blood coagulation scheme for the puffer fish, Fugu rubripes, has been reconstructed on the basis of orthologs of genes for mammalian blood clotting factors being present in its genome. As expected, clotting follows the same fundamental pattern as has been observed in other vertebrates, even though genes for some clotting factors found in mammals are absent and some others are present in more than one gene copy. All told, 26 different proteins involved in clotting or fibrinolysis were searched against the puffer fish genome. Of these, orthologs were found for 21. Genes for the "contact system" factors (factor XI, factor XII, and prekallikrein) could not be identified. On the other hand, two genes were found for factor IX and four for factor VII. It was evident that not all four factor VII genes are functional, essential active-site residues having been replaced in two of them. A search of the genome of a urochordate, the sea squirt, Ciona intestinalis, did not turn up any genuine orthologs for these 26 factors, although paralogs and/or constituent domains were evident for virtually all of them.

Amino Acid Sequence↗
PubMed2003

Regulation of PRAK subcellular location by p38 MAP kinases.

The p38 mitogen-activated protein kinase (MAPK) pathway plays an important role in cellular responses to inflammatory stimuli and environmental stress. p38 regulated/activated protein kinase (PRAK, also known as mitogen-activated protein kinase activated protein kinase 5 [MAPKAPK5]) functions downstream of p38alpha and p38beta in mediating the signaling of the p38 pathway. Immunostaining revealed that endogenous PRAK was predominantly localized in the cytoplasm. Interestingly, ectopically expressed PRAK was localized in the nucleus and can be redistributed by coexpression of p38alpha or p38beta to the locations of p38alpha and p38beta. Mutations in the docking groove on p38alpha/p38beta, or the p38-docking site in PRAK, disrupted the PRAK-p38 interaction and impaired the ability of p38alpha and p38beta to redistribute ectopically expressed PRAK, indicating that the location of PRAK could be controlled by its docking interaction with p38alpha and p38beta. Although the majority of PRAK molecules were detected in the cytoplasm, PRAK is consistently shuttling between the cytoplasm and the nucleus. A sequence analysis of PRAK shows that PRAK contains both a putative nuclear export sequence (NES) and a nuclear localization sequence (NLS). The shuttling of PRAK requires NES and NLS motifs in PRAK and can be regulated through cellular activation induced by stress stimuli. The nuclear content of PRAK was reduced after stimulation, which resulted from a decrease in the nuclear import of PRAK and an increase in the nuclear export of PRAK. The nuclear import of PRAK is independent from p38 activation, but the nuclear export requires p38-mediated phosphorylation of PRAK. Thus, the subcellular distribution of PRAK is determined by multiple factors including its own NES and NLS, docking interactions between PRAK and docking proteins, phosphorylation of PRAK, and cellular activation status. The p38 MAPKs not only regulate PRAK activity and PRAK activation-related translocation, but also dock PRAK to selected subcellular locations in resting cells.

Genes, Reporter↗
PubMed2003

The multidrug/oligosaccharidyl-lipid/polysaccharide (MOP) exporter superfamily.

The multidrug/oligosaccharidyl-lipid/polysaccharide (MOP) exporter superfamily (TC #2.A.66) consists of four previously recognized families: (a) the ubiquitous multi-drug and toxin extrusion (MATE) family; (b) the prokaryotic polysaccharide transporter (PST) family; (c) the eukaryotic oligosaccharidyl-lipid flippase (OLF) family and (d) the bacterial mouse virulence factor family (MVF). Of these four families, only members of the MATE family have been shown to function mechanistically as secondary carriers, and no member of the MVF family has been shown to function as a transporter. Establishment of a common origin for the MATE, PST, OLF and MVF families suggests a common mechanism of action as secondary carriers catalyzing substrate/cation antiport. Most protein members of these four families exhibit 12 putative transmembrane alpha-helical segments (TMSs), and several have been shown to have arisen by an internal gene duplication event; topological variation is observed for some members of the superfamily. The PST family is more closely related to the MATE, OLF and MVF families than any of these latter three families are related to each other. This fact leads to the suggestion that primordial proteins most closely related to the PST family were the evolutionary precursors of all members of the MOP superfamily. Here, phylogenetic trees and average hydropathy, similarity and amphipathicity plots for members of the four families are derived and provide detailed evolutionary and structural information about these proteins. We show that each family exhibits unique characteristics. For example, the MATE and PST families are characterized by numerous paralogues within a single organism (58 paralogues of the MATE family are present in Arabidopsis thaliana), while the OLF family consists exclusively of orthologues, and the MVF family consists primarily of orthologues. Only in the PST family has extensive lateral transfer of the encoding genes occurred, and in this family as well as the MVF family, topological variation is a characteristic feature. The results serve to define a large superfamily of transporters that we predict function to export substrates using a monovalent cation antiport mechanism.

Amino Acid Sequence↗
PubMed2003

Ischemic preconditioning decreases C-X-C chemokine expression and neutrophil accumulation early after liver transplantation in rats.

AIM: Polymorphonuclear neutrophil (PMN) plays a major role in liver ischemia/reperfusion injury. Protective effect of ischemic preconditioning (IP) has been confirmed in liver ischemia/reperfusion injury. The purpose of this study was to investigate the effect of IP on C-X-C chemokine expression and PMNs recruitment early after liver transplantation. METHODS: Male Sprague-Dawley rats were used as donors and recipients of orthotopic liver transplantation (OLT). The donor liver was stored 24 hours in University of Wisconsin (UW) solution at 4 degrees pre-implantation. IP was done by clamp of the portal vein and hepatic artery of the donor liver for 10 minutes followed by reperfusion for 10 minutes before harvesting. The neutrophilic infiltration in liver was quantified using a myeloperoxidase (MPO) assay. Intragraft expression of macrophage inflammatory protein-2 (MIP-2) mRNA was investigated with in situ hybridization. The serum levels of MIP-2 and tumor necrosis factor (TNF)-alpha were also monitored. RESULTS: After liver transplantation without IP, the hepatic MPO increased significantly compared with sham operated group. In IP group, PMN in liver indicated by MPO was reduced significantly. In situ hybridization showed no MIP-2 mRNA in sham group but dramatic expression in hepatocytes in non-IP group. In IP group, MIP-2 mRNA was significantly down-regulated. Similarly, serum MIP-2 and TNF-alpha levels were significantly elevated in non-IP group and both were reduced in IP group. CONCLUSION: IP might protect graft liver from preservation-reperfusion injury after OLT through down-regulating C-X-C chemokine expression of hepatocytes, and alleviating PMNs recruitment after reperfusion.

Animals↗
PubMed2003

Regulation of inducible nitricoxide synthase gene transcription by p38 mitogen-activated protein kinase in human embryonic kidney 293 cells.

OBJECTIVE: To study the transcriptional regulation of inducible nitric oxide synthase (iNOS) gene by p38 mitogen-activated protein kinase (MAPK). METHODS: With human embryonic kidney (HEK) 293 cells as the target and the assistance of lipofectamine-mediated co-transfection techniques and luciferase reporter gene systems, FLAG-tagged p38 isoforms (namely FLAG-p38 alpha, FLAG-p38 beta;, FLAG-p38 gamma and FLAG-p38 phi;) in pcDNA3, pcDNA3, piNOS-Luc and pCMV-beta; were transfected into HEK 293 cells, and the relative activity of luciferase was subsequently tested. RESULTS: Highest luciferase activity occurred only in p38 alpha group compared with the other three isoform groups under no stimulation. Under the stimulation by lipopolysaccharide (LPS), the luciferase activity of each group was obviously increased and the highest activity occurred in p38 beta group. CONCLUSION: LPS can induce transcription and activation of iNOS gene, and p38 MAPK is involved in the transcription regulation of iNOS gene in HEK 293 cells.

Cells, Cultured↗
PubMed2003

Construction of signal peptide-FRET fusion expression vectors and their expressions in NIH3T3 cells.

OBJECTIVE: To construct the fluorescence protein vector pairs with toll-like receptor 4 (TLR4) signal peptide, namely pECFP-C1-SP and pEYFP-C1-SP, therefore to make the application of fluorescence resonance energy transfer (FRET) possible in the study of the membrane protein interaction during lipopolysaccharide (LPS) recognition. METHODS: pECFP-C1-SP and pEYFP-C1-SP were constructed by means of site-directed mutagenesis, and the constructed plasmids were transiently transfected into NIH3T3 cells via lipofectamin to observe their intracellular expressions under a fluorescence microscope. RESULTS: DNA sequence analysis attested the validity of the constructed fluorescence vectors with signal peptide for FRET, and the expression of the vectors was located principally on the cell membrane as observed under fluorescence microscope. CONCLUSION: The constructed vectors TLR4 signal peptide are valid and capable of expressing on the cell membrane, therefore they can be effectively used in the study of the interaction between the membrane proteins.

3T3 Cells↗
PubMed2003

[The TNF-alpha-induced apoptosis of LA795 cells is mediated by MAP kinase kinase 6].

OBJECTIVE: To study the molecular mechanism of apoptosis of lung cancer cells stimulated by tumor necrosis factor alpha for the discovery of potential methods of gene therapy of lung cancer. METHODS: The apoptosis model of LA795 adenocarcinoma cells was performed. Recombinant adenovirus of MAP kinase kinase 6, and its constitutively active form and dominant negative form were prepared in 293 package cells. Protein kinase assay was used to detect the activity of MKK6 in cells. RESULTS: TNF-alpha stimulation increased the activity of MKK6 in LA795 lung cancer cells. The stimulation of TNF-alpha induced apoptosis of LA795 cells significantly. The infection of recombinant virus of constitutive active form of MKK6 also induced apoptosis of LA795 cells significantly, while the infection of recombinant virus of dominant negative form of MKK6 blocked the apoptosis of LA795 cells apparently. CONCLUSIONS: TNF-alpha induced apoptosis of LA795 cells is mediated by MKK6. It is possible to use MKK6 recombinant virus for gene therapy of lung cancer.

Adenocarcinoma↗
PubMed2003

[Construction of vector of his-tagged cytoplasmic fragment of human toll like receptor 4 and its expression in E.coli].

OBJECTIVE: To construction of vector of his-tagged cytoplasmic fragment of human Toll like receptor 4 (hTLR4) and its expression in E.coli. METHODS: hTLR4 cytoplasmic cDNA codon domain was amplified by polymerase chain reaction (PCR) and cloned into pET-DsbA2.0 plasmid expressing His-DsbA fusion protein. After being identified by the assay of restrictional enzyme and sequencing, His-Dsb A fusion proteins were induced with isopropy-beta-D-thiogalactoside (IPTG) and further purified. RESULTS: A fusion protein with molecular weight of 42 kd was obtained. CONCLUSION: hTLR4 which was constructed and expressed successfully under nondenaturing conditions provides a tool for further studies.

Cloning, Molecular↗
PubMed2003

[Study on mortality, incidence and risk factors of stroke in a cohort of elderly in Xi'an, China].

OBJECTIVE: To prospectively study the relationship between risk factors and stroke incidence and mortality in the Chinese elderly. METHODS: An analytic study in a cohort population of 1,268 male retired cadres in a military setting. A health-screening program was carried out for all cadres aged 55 years or older in Xi'an in February 1987. Baseline data on smoking, cholesterol, triglyceride, blood pressure, body mass index (BMI), histories of hypertension, hyperlipidemia and coronary heart disease (CHD), stroke, diabetes and family histories of cardiovascular disease were investigated. Main outcome measures were stroke incidence, stroke and all-cause mortality. RESULTS: The cohort was followed up until June 30, 2001 and a total number of follow-up person-year was 15,546. During the follow-up period, there were 113 new stroke cases identified and the adjusted incidence was 727 per 100,000 person-year. Forty-five deaths were due to stroke and the adjusted mortality was 289 per 100,000 person-year. Using Cox model analysis, after adjustment on age, total cholesterol, triglyceride, smoking, drinking and physical exercise, we noticed that the systolic pressure, BMI, history of CHD and hyperlipidemia were independent risk factors for stroke incidence and morality. CONCLUSION: The incidence and mortality of stroke in this cohort were lower than those in the same age group of general population. Monitoring and controlling body mass index and blood pressure level seemed to be important factors for the prevention of stroke in the elderly.

Aged↗
PubMed2003

[Ultrasound surveillance of cervical lymph node metastasis in thoracic esophageal carcinoma].

OBJECTIVE: To improve the accuracy of preoperative evaluation of cervical lymph node metastasis in thoracic esophageal squamous carcinoma. METHODS: Forty-two patients with thoracic esophageal squamous carcinoma underwent neck ultrasonography. Enlarged lymph nodes with their long axis greater than 10 mm and a short-to-long axis ratio greater than 0.5 were considered as metastatic. RESULTS: Preoperative neck ultrasonography revealed the enlarged lymph nodes in 16 patients, but only in 5 (31%) cases the nodes were palpable. Among them 9 were classified as metastatic (cM(1-LN)), including 4 patients with palpable nodes. In 5 cM(1-LN) patients surgical intervention was canceled and the remaining 37 patients underwent trans-thoracic esophagectomy. Cervical node metastasis (pM(1-LN)) was confirmed pathologically in 6 surgical patients, 4 with tumors invading the adventitia (pT3) and the other 2 into the surrounding structure (pT(4)) (pT(1), pT(2) vs. pT(3), pT(4), P = 0.020). All 6 pM(1-LN) patients had concomitant mediastinal node metastasis and 4 of them had upper abdominal node metastasis. Statistically significant relationship was detected between cervical and abdominal nodal status (r = 0.536, P = 0.007). In comparison with the results of pathological examination and treatment response, the accuracy and sensitivity were 81% and 95% (P = 0.043), 36% and 82% (P = 0.081), respectively, for palpation and ultrasonography. Five out of 39 (13%) patients had their therapy changed due to ultrasonographic findings. CONCLUSIONS: Neck ultrasonography for cervical lymphadenopathy is of high sensitivity and accuracy, which plays an important role in the preoperative evaluation and therapeutic decision-making.

Adult↗