Biomedical subjects

Min Sun

Publications and source records attributed to Min Sun.

At least 19 recordsLinked to original sources

PubMed2006

Cloning and expression of PDK4, FOXO1A and DYRK1A from the hibernating greater horseshoe bat (Rhinolophus ferrumequinum).

Pyruvate dehydrogenase kinase isoenzyme 4 (PDK4) cDNA was cloned from the brain of greater horseshoe bat (Rhinolophus ferrumequinum). The deduced amino acid sequence shares strong homology with these PDK4 of other mammals. Moreover, we partially cloned homologues of dual-specificity tyrosine-phosphorylated and regulated protein kinase 1A (DYRK1A), and forkhead box protein O1A (FOXO1A) from greater horseshoe bat. Among five different tissues tested, PDK4 mRNA was highly expressed in the heart, white adipose tissue and muscle, but weakly expressed in the brain and liver, while DYRK1A and FOXO1A were expressed in all five tissues. Moreover, the transcript levels of PDK4, DYRK1A, and FOXO1A were measured in the heart, white adipose tissue and muscle of hibernating and arousal greater horseshoe bats by Northern blot and real time PCR. The results showed that transcript level of PDK4 was significantly higher in white adipose tissue. Expression level of DYRK1A was significantly higher in hibernating state in white adipose tissue, and expression level of FOXO1A was significantly higher in muscle in aroused state. These results suggest that up-regulation of the transcript levels of PDK4 during hibernation were not regulated via DYRK1A and FOXO1A in white adipose tissue and muscle, and the possible presence of another isoenzyme of PDK which is responsible for the tissue-specific regulation of Pyruvate dehydrogenase complex (PDC) activity in the bat heart during hibernation.

Animals↗

PubMed2006

Degradation of phenolic compounds with hydrogen peroxide catalyzed by enzyme from Serratia marcescens AB 90027.

In this paper, the degradation of phenolic compounds using hydrogen peroxide as oxidizer and the enzyme extract from Serratia marcescens AB 90027 as catalyst was reported. With such an enzyme/H2O2 combination treatment, a high chemical oxygen demand (COD) removal efficiency was achieved, e.g., degradation of hydroquinone exceeded 96%. From UV-visible and IR spectra, the degradation mechanisms were judged as a process of phenyl ring cleavage. HPLC analysis shows that in the degradation p-benzoquinone, maleic acid and oxalic acid were formed as intermediates and that they were ultimately converted to CO2 and H2O. With the enzyme/H2O2 treatment, vanillin, hydroquinone, catechol, o-aminophenol, p-aminophenol, phloroglucinol and p-hydroxybenzaldehyde were readily degraded, whereas the degradation of phenol, salicylic acid, resorcinol, p-cholorophenol and p-nitrophenol were limited. Their degradability was closely related to the properties and positions of their side chain groups. Electron-donating groups, such as -OH, -NH2 and -OCH3 enhanced the degradation, whereas electron-withdrawing groups, such as -NO2, -Cl and -COOH, had a negative effect on the degradation of these compounds in the presence of enzyme/H2O2. Compounds with -OH at ortho and para positions were more readily degraded than those with -OH at meta positions.

Catalysis↗

PubMed2006

A novel approach for description of nonlinear field radiated from a concave source with wide aperture angle.

A new approach is proposed to study the nonlinear sound field radiated from a concave spherical source with a wide aperture angle. The nonlinear sound field is theoretically described by a set of equations deduced reversely from the second-order Westervelt nonlinear wave equation. To examine the validity of the theoretical model, numerical calculations are performed on a concave spherical radiator with the aperture angle wide up to 40 degrees. Numerical calculation is implemented by the finite difference time domain algorithm in the oblate spheroidal coordinate system. Numerical results are in agreement with those obtained by Kamakura's solutions.

Journal Article↗

PubMed2006

[Immunological regulation and treatment of Brucea javanica and Fructus Psoraleae on rats with Pneumocystis carinii pneumonia].

OBJECTIVE: To study the immunological regulation and treatment of Brucea javanica and Fructus Psoraleae, traditional Chinese medicine, on rats with Pneumocystis carinii pneumonia (PCP). METHODS: Rats were injected subcutaneously by dexamethasone. When the rats got Pc infected, they were divided into two groups: rats in one group were treated with the mixture of Brucea javanica and Fructus Psoraleae and another group was used as infected control. Control with normal rats was also established. Observations were made on the number of cysts in lungs and the changes of CD4+ T cells, CD8+ T cells and TNF-alpha in the serum to demonstrate the immunological regulation and killing effect of the medicine on cysts in the infected rats. RESULTS: The body weight of the rats treated with Brucea javanica and Fructus Psoraleae increased considerably than that of immunosuppressed rats and the normal control. The damaged lung got improved and repaired, and a significant cyst reduction was shown in the treated group. The CD4+ T cells, CD8+ T cells and level of TNF-alpha in serum also increased in the treated group significantly. CONCLUSION: The mixture of Brucea javanica and fructus psoraleae plays an immunological regulation on rats with Pneumocystis carinii pneumonia and shows certain killing effect on the cysts.

Animals↗

PubMed2006

Expression and purification of a mutant of human interleukin-2 in Pichia pastoris.

Interleukin (IL)-2 is a pharmacologically important cytokine secreted by T-lymphocytes. Recombinant IL-2 (rIL-2) has been modified and produced in many systems. Mass production of rIL-2 is the prerequisite for its wide application. Using a site-directed mutagenesis strategy, we first generated a gene coding for a new type of mutant of human IL-2 (MhIL-2), in which we replaced the cysteine-125 in human IL-2 with alanine, the leucine-18 with methionine, and the leucine-19 with serine. Then we investigated the possibility of its production of MhIL-2 in a Pichia pastoris system. High-level secreted expression of MhIL-2 was achieved by methanol induction. When purified with ultrafiltration, cation-exchange chromatography, and Sephadex G100 gel filtration, about 100 mg of MhIL-2 with high purity was obtained from 1 L of ferment supernatant. Biologic activity assay revealed that the purified recombinant protein displayed increased activity on proliferation of IL-2-dependent CTLL-2 cells. These results suggest that MhIL-2 is an improved IL-2 mutant that might hold great promise for clinical use, and that P. pastoris is an excellent system for the mass production of biologically active hIL-2.

Amino Acid Substitution↗

PubMed2006

Applicability of capillary electrophoresis to the analysis of trace rare earth elements in geological samples.

This study developed a methodology to analyze trace rare earth elements (REEs) in geological materials by capillary electrophoresis (CE). Changed from dilute HNO3 into a water medium by heating, REE ions are detectable at approximately 2 ng mL(-1). In the presence of coexisting elements from geological samples, REE separations were carried out. After sample fusion with Na2O2 and interference separation with ammonium pyrrolidinedithiocarbamate chelate, REE analytes were coprecipitated with Mg(OH)2 at pH 8.5, and then prepared into a water medium for CE determination. Using the standard addition method, this protocol was validated by analyses with better than 5% precision. This method was applied to geological materials; the REE results are in consistence with their certified values. With electrokinetic injection, internal standard (IS) selected among lanthanides is a prerequisite of high-quality REE data. An approach was proposed to derive the IS content for further correcting its contribution from unknown samples.

Journal Article↗

PubMed2006

[Prokaryotic expression and purification of recombination Salmonella invasion protein].

OBJECTIVE: To express recombinant Salmonella invasion protein A(InvA) in E. coli and purify it. METHODS: The invA gene of Salmonella was amplified by PCR from the Salmonella genome and cloned into expression vector pET-30c (+) to generate the pET-invA recombinants. They were comfirmed by restriction endonuclease digestion and sequence analysis. The verified recombinant was transformed into E. coli BL21 (DE3). After inducing with isopropyl-beta-D-thiogalactopyranoside (IPTG), the recombinant protein was purified via Ni-NTA affinity chromatography under denature conditions. The recombinant proteins were analyzed with SDS-PAGE and Western blot. RESULTS: The pET-invA recombinant for Salmonella was successfully constructed and the recombinant InvA protein was expressed in E. coli at a relatively high level. The SDS-PAGE results for the purified recombinant protein demonstrated that the purified protein had reached the electrophoresis purity. CONCLUSION: The successful expression of the Salmonella InvA protein will be very helpful for the further study on its antigenicity, immunological activity, and the development of rapid detection methods for Salmonella strains.

Animals↗

PubMed2006

[Toxicity and oxidative stress on rats by hexachlorobenzene].

OBJECTIVE: To study the toxicity on rats by hexachlorobenzene (HCB), and to explore the role of oxidative stress in the mechanism of HCB intoxication. METHODS: SD female rats were fed on a powdered diet containing 0.25 per thousand or 2.00 per thousand HCB for 14 days. The content of malondialdehyde (MDA) and the activity of total-superoxide dismutase (T-SOD), catalase (CAT) and glutathione peroxidase (GSH-PX) in cerebral cortex, hippocampus, liver tissue and serum were determined. Eleven biochemical indicators including alkaline phosphatase (ALP) were surveyed. RESULTS: (1) MDA levels in cerebral cortex, hippocampus, liver and serum of the high dosage group rats and that in hippocampus and serum of the low dosage group were significantly higher than that of the control group. (2) The activity of T-SOD was increased in cerebral cortex and hippocampus of the rats in both groups (P < 0.01), but decreased in the serum of the high dosage group (P < 0.01). (3) The activity of CAT was also increased in the hippocampus of rats in the high dosage group. (4) In cerebral cortex and hippocampus of the rats in the high dosage group and in the hippocampus of the rats in the low dosage group, the activity of GSH-PX was significantly higher compared with the control group. However, in liver of both dosage groups, the activity of GSH-PX was decreased (P < 0.01). (5) The activity of serum alkaline phosphatase of both dosage groups was also decreased, but the contents of both serum albumin and total cholesterol were significantly higher than those of the control group (P < 0.01). CONCLUSION: HCB can induce enhanced lipid peroxidation on SD rats, and the oxidative stress plays an important role in the mechanism of neurotoxicity and hepatotoxicity.

Animals↗

PubMed2005

Identification of a Spindlin homolog in gibel carp (Carassius auratus gibelio).

Spindlin has been suggested to play an important role during the transition from oocyte maturation to embryo development in mouse, but its homolog similar to the mouse Spindlin in molecular and expression characterization has not been identified up to now in other vertebrates. In this study, a full length of cDNA sequence is cloned and sequenced from the gibel carp (Carassius auratus gibelio). It contains 1240 nucleotides with an open reading frame of 771 nt encoding 257 amino acids. Based on its amino acid sequence alignment and comparison analysis with the known Spin family proteins, the newly cloned Spin is named Carassius auratus gibelio Spindlin (CagSpin). Its product could be detected from mature eggs to blastula embryos, but its content decreased from the two-cell stage, and could not be detected after the gastrula stage. It suggests that the CagSpin should be a maternal protein that is expressed during oocyte maturation, and plays a crucial role in early cleavage of embryogenesis. CagSpin is the first homolog similar to mouse spindlin identified in fish, and also in other vertebrates. GST pull-down assay reveals the first biochemical evidence for the association of CagSpin and beta-tubulin, the microtubule component. Therefore, CagSpin may play important functions by interacting with beta-tubulin and other spindle proteins during oocyte maturation and egg fertilization.

Animals↗

PubMed2005

Identification of three duplicated Spin genes in medaka (Oryzias latipes).

Gene and genomic duplications are very important and frequent events in fish evolution, and the divergence of duplicated genes in sequences and functions is a focus of research on gene evolution. Here, we report the identification and characterization of three duplicated Spindlin (Spin) genes from medaka (Oryzias latipes): OlSpinA, OlSpinB, and OlSpinC. Molecular cloning, genomic DNA Blast analysis and phylogenetic relationship analysis demonstrated that the three duplicated OlSpin genes should belong to gene duplication. Furthermore, Western blot analysis revealed significant expression differences of the three OlSpins among different tissues and during embryogenesis in medaka, and suggested that sequence and functional divergence might have occurred in evolution among them.

Amino Acid Sequence↗

PubMed2005

Nickel sulfide fire assay improved for pre-concentration of platinum group elements in geological samples: a practical means of ultra-trace analysis combined with inductively coupled plasma-mass spectrometry.

A method was developed for ultra-trace determination of all six platinum group elements (PGE) by inductively coupled plasma-mass spectrometry (ICP-MS). With involvement of Fe to the fusion charge compositions of the conventional NiS fire assay, a whole assay button in water may disintegrate into powder and then be dissolved with HCl. The insoluble residue was collected, and dissolved with HCl + H(2)O(2) in a sealed Teflon beaker. After the HCl + H(2)O(2) treatment the Os signal response is at least 10 times as high as that in HCl medium. With isotopic dilution method for determination of Os, all six PGE were analyzed in one sample preparation. This method was applied to a series of Chinese PGE certified reference materials, GBW 07288 to GBW 07294, and the results were found to be in reasonable agreement with the certified values. Limits of detection were assessed from the whole chemical procedure and they are 0.17 ng g(-1) for Ru, 0.01 ng g(-1) for Rh, 0.16 ng g(-1) for Pd, 0.03 ng g(-1) for Os, 0.07 ng g(-1) for Ir and 0.11 ng g(-1) for Pt. This method of precision (RSD%) was evaluated using two reference materials of GBW 07291 and GBW 07294, and it is within the range from 4.2% to 10.3%.

Journal Article↗

PubMed2005

Detecting novel low-abundant transcripts in Drosophila.

Increasing evidence suggests that low-abundant transcripts may play fundamental roles in biological processes. In an attempt to estimate the prevalence of low-abundant transcripts in eukaryotic genomes, we performed a transcriptome analysis in Drosophila using the SAGE technique. We collected 244,313 SAGE tags from transcripts expressed in Drosophila embryonic, larval, pupae, adult, and testicular tissue. From these SAGE tags, we identified 40,823 unique SAGE tags. Our analysis showed that 55% of the 40,823 unique SAGE tags are novel without matches in currently known Drosophila transcripts, and most of the novel SAGE tags have low copy numbers. Further analysis indicated that these novel SAGE tags represent novel low-abundant transcripts expressed from loci outside of currently annotated exons including the intergenic and intronic regions, and antisense of the currently annotated exons in the Drosophila genome. Our study reveals the presence of a significant number of novel low-abundant transcripts in Drosophila, and highlights the need to isolate these novel low-abundant transcripts for further biological studies.

Animals↗

PubMed2005

[A study on the hairy root culture and antitumor alkaloids production of Catharanthus roseus].

OBJECTIVE: To establish transformation system and obtain alkaloids from the hairy root of Catharanthus roseus. METHOD: Hairy roots were obtained by infecting the different explants of C. roseus. Culture conditions of hairy root were optimized. RESULT: The best transformation condition was leaf infected by two-day's pre-culture and two-day's co-culture and additional A(S) (hydroxyacetosyringone) 100 mg x L(-1). The inducing rate of hairy root was up to 86.25%. The best condition of hairy root culture was MS medium with sucrose as carbon material and lactalbumin as nitron material. The analysis result showed that the contents of total alkaloids in hairy roots were higher than explants and calli. CONCLUSION: Hairy root of C. roseus will be useful for the production of active components in C. roseus.

Alkaloids↗

PubMed2005

[On the association of tumor necrosis factor-alpha gene polymorphisms with the susceptibility to silicosis].

OBJECTIVE: To find out whether -308 and -238 locus (G --> A) mutation within the tumor necrosis factor-alpha gene (TNF-alpha) promoter region are associated with susceptibility to silicosis in the Han population of southwest China. METHODS: Governed by the principles of voluntatiness and cooperation, 75 patients with silicosis and 137 control with silica-exposure but without silicosis were recruited, and additionally, 140 elderly patients with silicosis and 135 healthy elderly (retired) controls were recruited in this case-control study. 5 ml peripheral vein blood was drawn from each subject. By means of polymerase chain reaction-restriction fragment length polymorphisms (PCR-RFLP) and sequencing techniques, TNF-alpha gene polymorphisms of all subjects were analyzed. RESULTS: The frequencies of TNF-alpha -308A and -238A in the 75 patients with silicosis were higher than those in the 137 controls (P < 0.01). After being adjusted for confounding factors, the -308A and the -238A were still associated with the presence of silicosis (P < 0.01). But the frequency of TNF-alpha -308A in the 140 elderly patients was significantly lower than that in the controls (P < 0.001). CONCLUSIONS: TNF-alpha gene -308 and -238 locus (G --> A) mutation might be related to the occurrence of silicosis and the severity of pulmonary fibrosis in silicosis among the Han population of southwest China, and TNF2 (-308A) allele might increase the risk of the disease.

Adult↗

PubMed2005

[Clustered shoot induction and rapid propagation on Pinellia ternate].

OBJECT: To establish the rapid propagation system of Pinellia ternate. METHOD: The Clustered shoots were induced by the explant lamina and petiole from the terminal bud of Pinellia ternate tuber in test tube. RESULT: The plantlets could regenerate from the lamina and petiole directly without via the callus. The MS Medium with 2.0 mg/L 6-BA and 0.1 mg/L NAA was optimal for the induction of culstered shoots from explants of lamina; the MS with 2.0 mg/L 6-BA and 0.25 mg/L NAA was best for the explants of petiole; and the 1/2 MS with 1.0 mg/L KT and 2.0 mg/L NAA was the better medium for induction of roots. CONCLUSION: The regenerated rate of Pinellia ternata can improve by inducing the clustered shoots from the explants of lamina and petiole directly.

Culture Media↗

PubMed2004

Development of Taqman RT-nested PCR system for clinical SARS-CoV detection.

Severe acute respiratory syndrome (SARS) is an acute newly emerged infectious respiratory illness. The etiologic agent of SARS was named 'SARS-associated coronavirus' (SARS-CoV) that can be detected with reverse transcription-polymerase chain reaction (RT-PCR) assays. In this study, 12 sets of nested primers covering the SARS-CoV genome have been screened and showed sufficient sensitivity to detect SARS-CoV in RNA isolated from virus cultured in Vero 6 cells. To optimize further the reaction condition of those nested primers sets, seven sets of nested primers have been chosen to compare their reverse transcribed efficiency with specific and random primers, which is useful to combine RT with the first round of PCR into a one-step RT-PCR. Based on the sensitivity and simplicity of results, the no. 73 primer set was chosen as the candidate primer set for clinical diagnoses. To specify the amplicon to minimize false positive results, a Taqman RT-nested PCR system of no. 73 nested primer set was developed. Through investigations on a test panel of whole blood obtained from 30 SARS patients and 9 control persons, the specificity and sensitivity of the Taqman RT-nested PCR system was found to be 100 and 83%, respectively, which suggests that the method is a promising one to diagnose SARS in early stages.

Adolescent↗

PubMed2004

Assisted infant toilet training in a Western family setting.

In the Western world, independent toilet training usually starts at age 18 months or later. In Asia and Africa, assisted toilet training traditionally starts between one and three months and is completed within approximately one year. This article reports a male infant who started caregiver-assisted toilet training at age 33 days in a Western family setting. During the first days, the caregiver made observations of the infant's bowel movement schedule and the cues he provided, from which she learned when to assist him to eliminate in the bathroom. During the elimination process, the infant was held in an "in-arms" position, with close contact between the infant's back and the caregiver's chest. Meanwhile, the caregiver gave vocal signals to prompt the infant to eliminate. Successful bowel training was completed at five months. This case report shows that early infant toilet training is possible in a Western family setting if the caregiver properly learns the infant's natural elimination timing and signals.

Age Factors↗

PubMed2004

Toilet training.

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Age Factors↗