Biomedical subjects

Kai Yang

Publications and source records attributed to Kai Yang.

At least 37 records · Page 2Linked to original sources

PubMed2005

Activation of c-Jun N-terminal kinase (JNK) pathway by HSV-1 immediate early protein ICP0.

The immediate early protein ICP0 encoded by herpes simplex virus 1 (HSV-1) is believed to activate transcription and consequently productive infection. The precise mechanisms of ICP0-mediated transactivation are under intensive study. Here, we demonstrate that ICP0 can strongly activate AP-1 responsive genes specifically. This activation is inhibited by c-Jun (S73A), c-Jun (S63/73A), TAK1 (K63W), but not by p38 (AF), ERK1 (K71R), ERK2 (K52R) and TRAF6 (C85A/H87A). We further investigate the relevancy of ERK, JNK and p38 MAPK pathways using their respective inhibitors PD98059, SP600125 and SB202190. Only SP600125 significantly attenuates the AP-1 responsive gene activation by ICP0. Consistent with these, the JNK is remarkably activated in response to ICP0, and this JNK activation is shown to be significantly attenuated by TAK1 (K63W). It turns out that ICP0 interacts specifically with TAK1 and stimulates its kinase activity. These findings reveal a new molecular mechanism ICP0 explores to regulate gene expression.

Cell Line↗

PubMed2005

Characterization of p24 gene of Spodoptera litura multicapsid nucleopolyhedrovirus.

Spodoptera litura multicapsid nucleopolyhedrovirus (SpltMNPV) p24 gene is 753 bp long, potentially encoding 244 amino acids with a predicted molecular weight of 27.3 kDa. Homology analysis indicated that SpltMNPV P24 has 20-36% amino acid identity with that of other known baculoviruses. RT-PCR results showed that the p24 gene is transcribed actively at the late stage of infection and the mRNA start site was mapped within a consensus baculovirus late promoter sequence (ATAAG). Western blot analysis of extracts from SpltMNPV-infected S. litura cells detected a specific 28 kDa protein, and this protein was not N-glycosylated. Structural localization revealed that SpltMNPV P24 was associated with the nucleocapsid of occlusion-derived virus (ODV) as a complex form of 83 kDa.

Amino Acid Sequence↗

PubMed2005

Identification of the apoptosis inhibitor gene p49 of Spodoptera litura multicapsid nucleopolyhedrovirus.

Baculoviruses possess two types of genes that suppressed apoptosis, p35 and inhibitor of apoptosis (iap). Computer-assisted analysis indicated that Spodoptera litura multicapsid nucleopolyhedrovirus (SpltMNPV) ORF55 (designated as the p49 gene) display 79 and 31% amino acid identity with Spodoptera littoralis (Spli)MNPV P49 and Autographa californica (Ac)MNPV P35, respectively, Splt MNPV putative P49 contains a peptide cleavage site TVTDG recognized by death caspases. In marker rescue assay, Splt-p49 was able to suppress apoptosis induced by infection of a mutant AcMNPV deficient in p35 and rescue the mutant virus replication from apoptosis in Sf-9 cells.

Amino Acid Sequence↗

PubMed2005

vlf-1 deletion brought AcMNPV to defect in nucleocapsid formation.

Recent studies have provided direct evidence that the baculovirus very late factor 1 (VLF-I) of Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV) was essential for BV production. To elucidate how vlf-1 deletion blocks BV production we generated a vlf-1 knockout bacmid by ET-recombination technology on AcMNPV bacmid propagated in Escherichia coli. Bacmid DNA transfection and supernatant passage assay revealed that the vlf-1 knockout bacmid was unable to replicate in cell culture, while vlf-1 repair bacmid, which was generated by transposition of the vlf-1 ORF under control of its native promoter into polyhedrin gene locus of vlf-1 knockout bacmid, resumed viral replication ability at wildtype levels. Results of these assays proved the correct construction of the vlf-1 knockout bacmid. Subsequent electron microscopy revealed that the vlf-1 knockout bacmid failed to form nueleocapsid in the nuclei of the transfected cells. Instead, intensely electron-dense virogenic stroma characteristic of viral DNA synthesis were observed. Thus, it is demonstrated for the first time that vlf-1 knockout blocked nucleocapsid formation and the defective nucleocapsid formation resulted in the abolishment of BV and ODV production. Possible roles of vlf-1 in genome processing are suggested and discussed.

Animals↗

PubMed2005

Herpes virus proteins ICP0 and BICP0 can activate NF-kappaB by catalyzing IkappaBalpha ubiquitination.

The immediate early proteins ICP0 and BICP0 from Herpes virus are promiscuous activators of both viral and cellular genes and play a critical role in virus life cycle. Here we report that ICP0 and BICP0 could induce NF-kappaB translocation from cytoplasm into nucleus and strongly activate NF-kappaB responsive genes specifically. This process was dependent on the RING domain of both proteins. In addition, ICP0 interacted specifically with IkappaBalpha and its activating effect was attenuated by Ubch5A(C85A) and MG132, but not by IkappaBalpha(S32A/S36A). Remarkably, IkappaBalpha was poly-ubiquitinated by both ICP0 and BICP0, in vitro and in vivo. These data indicate that ICP0 and BICP0, functioning as ubiquitin ligases, are bona fide activators of NF-kappaB signaling pathway. Our study identifies a new way ICP0 and BICP0 explore to regulate gene expression.

Animals↗

PubMed2005

Influence of pH on pesticide sorption by soil containing wheat residue-derived char.

Field burning of crop residues incorporates resulting chars into soil and may thus influence the environmental fate of pesticides in the soil. This study evaluated the influence of pH on the sorption of diuron, bromoxynil, and ametryne by a soil in the presence and absence of a wheat residue-derived char. The sorption was measured at pHs approximately 3.0 and approximately 7.0. Wheat char was found to be a highly effective sorbent for the pesticides, and its presence (1% by weight) in soil contributed >70% to the pesticide sorption (with one exception). The sorption of diuron was not influenced by pH, due to its electroneutrality. Bromoxynil becomes dissociated at high pHs to form anionic species. Its sorption by soil and wheat char was lower at pH approximately 7.0 than at pH approximately 3.0, probably due to reduced partition of the anionic species of bromoxynil into soil organic matter and its weak interaction with the carbon surface of the char. Ametryne in its molecular form at pH approximately 7.0 was sorbed by char-amended soil via partitioning into soil organic matter and interaction with the carbon surface of the char. Protonated ametryne at pH approximately 3.0 was substantially sorbed by soil primarily via electrostatic forces. Sorption of protonated ametryne by wheat char was also significant, likely due not only to the interaction with the carbon surface but also to interactions with hydrated silica and surface functional groups of the char. Sorption of ametryne by char-amended soil at pH approximately 3.0 was thus influenced by both the soil and the char. Environmental conditions may thus significantly influence the sorption and behavior of pesticides in agricultural soils containing crop residue-derived chars.

Absorption↗

PubMed2005

Characterization of gp41 gene of Spodoptera litura multicapsid nucleopolyhedrovirus.

Spodoptera litura multicapsid nucleopolyhedrovirus (SpltMNPV) gp41 gene is 993 bp long and the protein encoded by this gene has 6-66% amino acid identities with other known baculovirus GP41 proteins. Slgp41 transcripts were detected from 12 to 96 h post-infection (p.i.) and the mRNA start site was mapped within a consensus baculovirus late promoter sequence (ATAAG). Western blot analysis of extracts from SpltMNPV-infected S. litura cells detected a 41 kDa protein, and this protein was present in the nucleus of infected cells from 12 to 96 h p.i., whereas in the cytoplasm from 24 to 96 h p.i. Structural localization confirmed that SlGP41 is associated with the envelope of occlusion-derived virus (ODV). Lectin-binding assay showed that three lectins erythrina cristaglli lectin (ECL), lycopersicon esculentum lectin (LEL), and bandeiraea simlicifolia lectin (BSL) recognizing N-acetylglucosamine were specifically bound to SlGP41. It was proposed that SlGP41 is an O-glycoprotein.

Amino Acid Sequence↗

PubMed2005

Use of fluorometry for determination of skim milk powder adulteration in fresh milk.

A FAST (fluorescence of advanced Maillard products and Soluble Tryptophan) method for identification of reconstituted milk made from skim milk powder in the fresh milk was developed. Considering milk and skim milk powders variations from different seasons and countries, milk was collected from different dairy farms in different seasons and skim milk powders were collected from different countries to measure the Tryptophan (Trp), advanced Maillard products (AMP) fluorescence values. The results showed that there were differences (P<0.01) between raw and reconstituted milk. The plot of values in each mixed level of raw and reconstituted milk had a correlation coefficient >0.97. The FAST method is a simple, rapid, low-cost and sensitive method enabling the detection of 5% reconstituted milk in fresh milk. The measurement of the Trp, AMP fluorescence values and calculation of the FAST index is a suitable method for large-scale monitoring of fresh milk samples.

Animals↗

PubMed2005

[Willingness to pay for ecosystem services of urban river in Shanghai].

The contingent valuation method (CVM) is one of the most dominating and standard techniques for eliciting the willingness to pay (WTP) for the ecosystem services provided by environment and resources. Taking Zhangjiabang Creek, a model project in the comprehensive management of urban river in China, as a case study, 800 payment card CVM questionnaires were surveyed and 646 as useful questionnaires were feed back in August 2003, then, the mean WTP, 195.07 - 253.04 Yen per person every year in the future 3 years, to the ecosystem services of the urban river was got in the payment card CVM study, and the figure was compared to some other river CVM studies. Distribution shape and range of WTP were probed, and the regression relationship between respondents WTP and their socioeconomic information such as income, education level, donation experience, and environmental attitude was discussed, what's important, an environmental economics explanation was given to the regression results. Some biases which influence the mean WTP of payment card CVM are inspected and corresponding countermeasures were seriously noticed and implemented in the survey. Finally the critiques and controversies that CVM is faced with were advanced, but the reliability of CVM is also given based upon environmental decision-making theory.

China↗

PubMed2005

[Synthesis of diacylglycerol using immoblized regiospecific lipase in continuously operated fixed bed reactors].

Diacylglycerol, DAG, because of its multifunctional and nutritional properties, attracted considerable attention recently. Enzymatic synthesis of diacylglycerols from linoleic acid was investigated in a solvent-free reaction in a continuously operated fixed bed reactors containing Lipozyme RM IM. By appropriate manipulation of the fluid-residence time, the relative proportions of the various acylglycerols in the effluent stream can be controlled. In addition, the presence of excess glycerol is effective for the removal of water produced during the esterification reactions. Under the conditions of molar ratio of linoleic acid to glycerol of 0.5, the immoblized enzyme maintained high stability and allowed the reaction to continue for 10 days without significant deterioration in enzyme activity. It was determined that the conversion of fatty acid, content of 1,3-DAG and volume efficiency of reactor reached optima under the conditions: a packaged-bed reactor(with a ratio of packed length to inner diameter of 7.8), reacting temperature at 65 degrees C, molar ratio of linoleic acid to glycerol of 0.5, and feeding flow rate of 1.2 mL/min.

Catalysis↗

PubMed2005

[Experimental study of cisplatin loaded polylactic acid-polyethylene glycol nano-particles for targeting oral carcinoma].

OBJECTIVE: To investigate the target deliver of Cisplatin to oral carcinoma tissues by intravenous injection of Cisplatin loaded polylactic acid- polyethylene glycol nanoparticles (CDDP-PLA-PEG-NP). METHODS: CDDP-PLA-PEG-NP was prepared by the emulsion-solvent evaporation method. The buccal cancer model was established in 64 golden hamsters, which were divided randomly into two groups for 32 animals in each group, CDDP-PLA-PEG-NP (6.6 mg/kg) and CDDP (1 mg/kg) were respectively injected into mice tail vein. At 0.083, 0.5, 1, 2, 4, 6, 12, 24 h after drug administration. 4 animals in each group were sacrificed and CDDP concentration in the plasma and tumor were determined by high performance liquid chromatography. Targeting ability was evaluated by targeting index (TI), selectivity index (SI) and relative extraction efficiency (re). RESULTS: The average diameter of CDDP-PLA-PEG-NP was (143.2 +/- 1.8) nm. The diameter distribution was from 103.5 nm to 175.8 nm. Drug loading and embedding ratio were (15.2 +/- 0.9) %, (89.0 +/- 0.8) % respectively. Values of TI and SI are more than 1 at 8 time points. The area under CDDP concentration-time curve of oral carcinoma tissues in CDDP-PLA-PEG-NP group was 10.36 times as many as that in CDDP group. CONCLUSION: CDDP-PLA-PEG-NP can specifically deliver CDDP to oral carcinoma tissues by vein injection. Stealth anticancer nano-particle system can be regarded as a valuable drug deliver system to treat oral carcinoma.

Animals↗

PubMed2005

[Correlation between oral airflow ratio and craniofacial, airway and dental morphology].

OBJECTIVE: To investigate the correlation between airflow ratio and craniofacial, airway and dental morphology. METHODS: Seventy-two subjects aged 11 to 14 years were selected. The airflow ratio was measured by the system for the simultaneous measurement of oral and nasal respiration. Eighty-six variables of craniofacial, airway and dental morphology were acquired based on cephalometric films and models, from which 16 significant variables were selected. Multiple regression analysis (backward) and linear regression analysis were carried out in order to acquire morphological variables that had closer correlation with the airflow ratio. RESULTS: Four variables were found to have closer correlated association with the airflow ratio (P < 0.05), which were ANS-Me/N-Me, Ar-Go-Me, P-T, SHJK orderly and the coefficients were 3.359, 0.012, -0.013 and -0.021, respectively. CONCLUSIONS: Craniofacial morphology was related to the respiratory mode.

Adolescent↗

PubMed2004

The coiled-coil domain of TRAF6 is essential for its auto-ubiquitination.

Tumor necrosis factor receptor-associated factor 6 (TRAF6) is a crucial signaling transducer that regulates a diverse array of physiological processes, including adaptive immunity, innate immunity, and bone metabolism. Importantly, it is essential for activating NF-kappaB signaling pathway in response to interleukin-1 and Toll-like receptor ligands. Previously, we characterized TRAF6 to be a ubiquitin ligase. In combination with the ubiquitin conjugating enzyme complex Ubc13/Uev1A, TRAF6 could catalyze the formation on itself of unique Lys-63 linked polyubiquitin chain that positively regulated NF-kappaB signaling pathway. However, it remains unknown how this auto-ubiquitination process is regulated. In this study, we found that the coiled-coil domain of TRAF6 was essential for its auto-ubiquitination and activating NF-kappaB signaling pathway. This domain served not as the specific target where the polyubiquitin chain was linked, but as a specific bridge to recruit Ubc13/Uev1A.

Animals↗

PubMed2004

Self-assembly of ordered, robust, three-dimensional gold nanocrystal/silica arrays.

We report the synthesis of a new nanocrystal (NC) mesophase through self-assembly of water-soluble NC micelles with soluble silica. The mesophase comprises gold nanocrystals arranged within a silica matrix in a face-centered cubic lattice with cell dimensions that are adjustable through control of the nanocrystal diameter and/or the alkane chain lengths of the primary alkanethiol stabilizing ligands or the surrounding secondary surfactants. Under kinetically controlled silica polymerization conditions, evaporation drives self-assembly of NC micelles into ordered NC/silica thin-film mesophases during spin coating. The intermediate NC micelles are water soluble and of interest for biolabeling. Initial experiments on a metal-insulator-metal capacitor fabricated with an ordered three-dimensional gold nanocrystal/silica array as the "insulator" demonstrated collective Coulomb blockade behavior below 100 kelvin and established the current-voltage scaling relationship for a well-defined three-dimensional array of Coulomb islands.

Journal Article↗

PubMed2004

Characterization of bro-a gene of Spodoptera litura multicapsid nucleopolyhedrovirus.

Spodoptera litura multicapsid nucleopolyhedrovirus (SpltMNPV) ORF120 (designated as the bro-a gene) is a member of the unique multigene family called the baculovirus repeated ORFs (bro) family. Computer-assisted analysis revealed that BRO-A does not contain the conserved Bro-N domain in its N-terminus, but contains a single-stranded DNA binding motif near its C-terminus. Transcriptional analysis indicated that bro-a transcript initiated within a baculovirus consensus early start site motif (ATCAGT). In vitro the bro-a gene transcript was present at 12 h post infection (p.i.) and remained detectable up to 96 h p.i. Western blot analysis of BRO-A expression in SpltMNPV infected S. litura cells showed that it was present from 72 h to 96 h p.i. in vitro. Analysis of extracts from nuclear structures indicated that BRO-A could not be extracted with DNA or proteins which bind to DNA.

Amino Acid Sequence↗

PubMed2004

Kinematics of the thoracic T10-T11 motion segment: locus of instantaneous axes of rotation in flexion and extension.

The purpose of this study was to determine the locations and loci of instantaneous axes of rotation (IARs) of the T10-T11 motion segment in flexion and extension. An anatomically accurate three-dimensional model of thoracic T10-T11 functional spinal unit (FSU) was developed and validated against published experimental data under flexion, extension, lateral bending, and axial rotation loading configurations. The validated model was exercised under six load configurations that produced motions only in the sagittal plane to characterize the loci of IARs for flexion and extension. The IARs for both flexion and extension under these six load types were directly below the geometric center of the moving vertebra, and all the loci of IARs were tracked superoanteriorly for flexion and inferoposteriorly for extension with rotation. These findings may offer an insight to better understanding of the kinematics of the human thoracic spine and provide clinically relevant information for the evaluation of spinal stability and implant device functionality.

Biomechanical Phenomena↗

PubMed2004

Effects of cervical cages on load distribution of cancellous core: a finite element analysis.

METHODS: The study was designed to analyze the load distribution of the cancellous core after implantation of vertical ring cages made of titanium, cortical bone, and tantalum using the finite element (FE) method. The intact FE model of C5-C6 motion segment was validated with experimental results. RESULTS: The percentage of load distribution in cancellous core dropped by about one-third of the level for the intact model after the cage implantation. The difference among cages made of different materials (or different stiffnesses) was not very obvious. CONCLUSIONS: These results implied that the influence of the cage on the load transfer in the cancellous core is greatly related to the cage's dimensions and position within the intervertebral space. The dimension and position of the cage that least disturb the load distribution in cancellous core could be criteria in cage development.

Cadaver↗

PubMed2003

Power of linkage analysis using traits generated from simulated longitudinal data of the Framingham Heart Study.

The Framingham Heart Study is a very successful longitudinal research for cardiovascular diseases. The completion of a 10-cM genome scan in Framingham families provided an opportunity to evaluate linkage using longitudinal data. Several descriptive traits based on simulated longitudinal data from the Genetic Analysis Workshop 13 (GAW13) were generated, and linkage analyses were performed for these traits. We compared the power of detecting linkage for baseline and slope genes in the simulated data of GAW13 using these traits. We found that using longitudinal traits based on multiple follow-ups may not be more powerful than using cross-sectional traits for genetic linkage analysis.

Adult Children↗