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Biomedical subjects

Fang Wang

Publications and source records attributed to Fang Wang.

At least 199 records · Page 11Linked to original sources
PubMed2004

Preferential codons enhancing the expression level of human beta-defensin-2 in recombinant Escherichia coli.

Human beta-defensin-2 (hBD2) is a small antimicrobial peptide with potential as a therapeutic agent. The effect of codon usage on the expression of hBD2 in Escherichia coli was studied. Two coding sequences encoding the same hBD2 precursor were both expressed as fusion protein with thioredoxin in E. coli BL21 (DE3). One is the wild-type human cDNA and the other is a gene synthesized by a PCR-based method in which rare codons were altered to those frequently used in E. coli. The expression level of recombinant hBD2 was over 50% of the total cellular protein when the synthetic gene with preferential codons was employed which was a 9-fold enhancement over the wild-type cDNA. The result shows the codon bias of the host was a major barrier in high-level expression of recombinant hBD2 and suggests a similar approach may be used in the expression of other defensins in E. coli.

Amino Acid Sequence↗
PubMed2004

Electrophysiological effects of anthopleurin-Q on rat hepatocytes.

AIM: To study the effects of AP-Q on CCl(4)-induced acute liver injury, delayed outward potassium current (I(K)), inward rectifier potassium current (I(K1)) and calcium release-activated calcium current (I(CRAC)) in isolated rat hepatocytes. METHODS: A single dose of CCl(4) (10 microg/mL, ip) was injected to induce acute liver injury in rats. Serum aminotransferase activities were determined. Whole cell patch-clamp techniques were used to investigate the effects of AP-Q on delayed outward potassium current (I(K)), inward rectifier potassium current (I(K1)) and calcium release-activated calcium current (I(CRAC)). RESULTS: AP-Q (3.5 and 7 microg/kg) pretreatment significantly reduced ALT and AST activities. AP-Q 0.1-100 nM produced a concentration-dependent increase of I(K) with EC(50) value of 5.55+/-1.8 nM (n=6). AP-Q 30 nM shifted the I-V curve of I(K) leftward and upward. CCl(4) 4 mM decreased I(K) current 28.6+/-6.5% at 140 mV. After exposure to CCl(4) for 5 min, AP-Q 30 nM attenuated the decrease of I(K) induced by CCl(4) close to normal amplitude. AP-Q 0.01-100 nM had no significant effect on either inward or outward components of I(K1) at any membrane potential examined. AP-Q 0.1-100 nM had no significant influence on the peak amplitude of I(CRAC), either, and did not affect the shape of its current voltage curve. CONCLUSION: AP-Q has a protective effect on CCl(4)-induced liver injury, probably through selectively increased I(K) in hepatocytes.

Alanine Transaminase↗
PubMed2004

[Susceptibility change to HBV in primary culture of first trimester human fetal hepatocytes].

OBJECTIVES: By culturing primary early (8 to 12-weeks-old) human fetal hepatocytes with different conditions, to study the status of cell susceptibility to HBV. METHODS: During primary culture of 10-weeks-old human fetal hepatocytes with serum-free medium adding different differentiation-induced ingredients, to inoculate cell with HBV at certain time. Cell shape, function and markers of HBV infection are measured. RESULTS: 6 days after seeding, markers of mature hepatocytes are observed in cells cultured with 2.5mmol/L phenobarbital sodium, and these cells show susceptibility to HBV. Other ingredients cannot render hepatocytes susceptible to HBV. CONCLUSION: Phenobarbital sodium induces differentiation and susceptibility to HBV in primary culture of early human fetal hepatocytes.

Cell Differentiation↗
PubMed2004

[Expression changes of tau protein and microtubule-associated proteins in testis intersitium of rats].

OBJECTIVE: To examine the expression of the tau protein and microtubule-associated proteins in the testis interstitium of aged and young rats. METHODS: Sprague-Dawley male rats were divided into a young group(6 months, n = 10) and an aged group(28 months, n = 10). The two steps immunohistochemistry method with the antibody against tau protein and MAP alpha was performed on the testis tissues of the rats. RESULTS: The results showed that the immunoreactive cells of tau protein of the testis interstilial of the aged rats obviously increased(P < 0.001) than those of the young, while the immunoreactive cells of the microtubule-associated proteins decreased(P < 0.01) in the aged. CONCLUSION: The changes in the expression of the tau protein and microtubule-associated proteins may be related to the aging process of the testis.

Aging↗
PubMed2004

[Expression of the partial protein encoded by mutated COL4A5 gene and analysis of the structure by circular dichroism].

OBJECTIVE: To analyze the protein structure encoded by COL4A5 gene with a missense mutation and to discuss the effect of gene mutation on basic structure and predicted secondary structure of the encoded protein. METHODS: A fragment of cDNA with a g.3246G T mutation resulting in p.G1015V from an X-linked Alport patient, and that of corresponding cDNA from a control were expressed in E.coli. The recombinant and mutant polypeptide was a fragment of COL4A5, containing 158 amino acid residues with a glycine to valine substitution mutation in it. The secondary structure of the two recombinant proteins was analyzed using circular dichroism(CD) spectroscopy. RESULTS: CD spectra of the control exhibited a negative peak near 200 nm whereas that of the patient exhibited a negative peak near 220 nm. The magnitude of the negative peak of the patient decreased as compared with that of the control. Furthermore, secondary structure of the control polypeptide was mainly composed of beta-sheet and random coil without alpha-helix, whereas that of the patient presented 12.9% alpha-helix. CONCLUSION: Not only local structure of the substitution site but also folding kinetics of the entire alpha5 chain may be changed due to Gly-->Val substitution in Alport syndrome. We speculate that the abnormally folded polypeptide chain may not be assembled into the triple helix and the network of type IV collagen, or may be assembled into loosen triple-helix then degraded easily, resulting in the pathognomonic ultrastructural changes of the glomerular basement membrane.

Adult↗
PubMed2004

Separation of chlorinated hydrocarbons and organophosphorus, pyrethroid pesticides by silicagel fractionation chromatography and their simultaneous determination by GC-MS.

A silicagel fractionation procedure for environmental sample extracts, which separates chlorinated hydrocarbons (CHCs) and organophosphorus, pyrethroid pesticides into two groups for subsequent instrumental analysis, was developed in this study. This method was achieved by optimizing the fraction cut-off volume of elution and different solvents. Using fully activated silica gel and cut-off CHCs collection after 10 ml 10% dichloromethane (DCM) in n-hexane passing through the column resulted in satisfactory separation of CHCs and organophosphorus, pyrethroid pesticides. This procedure had a higher reliability for CHCs than for organophosphorus, pyrethroid pesticides, because there is a relatively reliable recovery for CHCs. This approach is less expensive due to reducing sample pre-treatment time and solvent consumption.

Chemical Fractionation↗
PubMed2004

[Clinical characteristics of bronchiolitis caused by human metapneumovirus in infants].

OBJECTIVE: The fact that the acute lower respiratory infections (ALRI) are associated with a newly discovered virus, human metapneumovirus (hMPV), has been shown in several studies. The authors conducted this study to understand the etiological and clinical characteristics of bronchiolitis, one of the most common ALRI in infants, caused by hMPV. METHODS: Nasopharyngeal aspirate specimens from 54 out of 126 infants with bronchiolitis admitted to the Children's Hospital Affiliated to Capital Institute of Pediatrics, Beijing from November 2002 to February 2003 were examined for hMPV gene fragments by reverse transcription-polymerase chain reaction (RT-PCR). Prior to the detection, the specimens were confirmed as negative for the common respiratory pathogens including RSV, influenza A and B, parainfluenza I, II, III, adenovirus, Mycoplasma pneumoniae by indirect immunofluorescence test, virus isolation and ELISA test. The clinical data of the patients diagnosed etiologically as hMPV infection analyzed included the infants' age, sex, the degree of fever, the severity of wheezing and clinical Lowell score, the findings of chest examination and chest X-ray, the white blood cell count and blood gas analysis, the course of the disease, the major treatments and the outcome of the disease. RESULTS: Twenty-one specimens showed the predicted 213 bp PCR products in agarose gel and the positive rate was 16.7% of all patients (21/126) and 39% of the patients with negative results for common respiratory pathogens detections (21/54). The range of patients' age was 2 - 15 months and the young infants with hMPV bronchiolitis (1 - 6 month of age) accounted for 62% and the male:female ratio was 3.2:1. The patients presented a low-medium grade fever (T < 39 degrees C) accounted for 86%; 81.0% of patients had a white blood cell count lower than 10.0 x 10(9)/L. The radiological findings were patchey opacity in both lungs (68%) and(or) hyperinflation (62%). Assessed by the Lowell score system, 5 out of 21 cases were considered as severe cases. The major clinical findings of hMPV bronchiolitis had no significant difference compared with that of subgroup A hRSV bronchiolitis, and showed longer course of disease than that of subgroup B hRSV bronchiolitis (P < 0.01). CONCLUSIONS: Of the infants with bronchiolitis hospitalized in our hospital from November of 2002 through February of 2003, 16.7% were caused by hMPV infection. These data showed that the major clinical characteristics and the outcome of treatment of hMPV bronchiolitis had no statistically significant difference compared to the cases with either subgroup A or subgroup B hRSV infection.

Bronchiolitis↗
PubMed2004

[Soil particle size fractionation with centrifugation method].

According to the rotor size of Mandal RC5C and Stoks' law, a segregation procedure for soil particle size fractionation was designed, and used for the particle separation of Huangmian soil(Calcaric cambisols, FAO), Huihe soil (Haplic greyxems, FAO), and Helu soil(Calcic kastanozems, FAO) in the Loess Plateau of China, and of Orthic Brown Chernozem, and Orthic Black Chernozem in Canadian Prairie. The fractionation results of the 5 soils by using this procedure were in line with those of the standard pipette method.

Centrifugation↗
PubMed2004

[Effect of acetic acid on adsorption of acid phosphatase by some soil colloids and clay minerals].

This paper studied the effect of acetic acid with different concentrations and pH values on the adsorption of acid phosphatase by some soil colloids and clay minerals (SCCM). The results showed that the pH values for the maximum adsorption of the enzyme were between the IEP of the enzyme and the PZC of SCCM. In the acetic acid systems, the amount of the enzyme adsorbed by SCCM was in the order of goethite >> yellow brown soil > latosol > kaolinite > delta-MnO2. A remarkable influence of acetic acid concentration on the adsorption amount and the binding energy of the enzyme was observed. With the increase of the concentration from 0 to 200 mmol.L-1 in the system, acetic acid exhibited an enhanced effect, followed by an inhibition action on the adsorption of the enzyme on SCCM. The changes of the binding energy (K value) for the enzyme on SCCM were on the contrary to those of the maximum adsorption. The possible mechanisms for the influence of acetic acid on the adsorption of enzyme by SCCM were also discussed.

Acetic Acid↗
PubMed2004

[Effects of different temperatures on the growth and energy budget of Chinese shrimp, Fenneropenaeus chinensis].

The effect of temperature on the growth and energy budget of Chinese shrimp Fenneropenaeus chinensis was studied at 18, 22, 25, 28, 31 and 34 degrees C. The results showed that its specific growth rate in terms of body weight and energy accumulation increased with temperature between 18 degrees C and 31 degrees C, and then decreased significantly at 34 degrees C. The similar trend was observed in food consumption and apparent digestion rate. The food conversion efficiency in weight and energy were 28.99%-53.09% and 15.70%-7.24%, respectively, which decreased with increasing temperature. The optimum temperature for the growth of shrimp was calculated from the relationship of SGR, which was 29.7 degrees C in this study. The energy budget of shrimp showed that the energy assimilated from food decreased with increasing temperature, while that spent in metabolism increased with increasing temperature. The results indicated that the high growth rate of Chinese shrimp at suitable temperature mainly resulted from the significant increase of food consumption and apparent digestion rate at corresponding temperature regimes.

Algorithms↗
PubMed2004

[Concepts and relative analytical techniques of soil organic matter].

The research of soil organic matter (SOM) has been highlighted in soil science. In the past 50 years, new perspectives in the relationship between SOM and sustainability of atmosphere and biomosphere, and strong motivation to find a vivid index for soil quality variation induced the transformation in concepts and analytical techniques of SOM: the curiousness to humic substances faded off since they were dull to anthropogenic activities, and interests were focused on the light fraction of organic matter (LFOM), organic carbon associated with different mineral particles in size, particulate and intra-particulate organic matter (POM and iPOM), water soluble organic matter (WSOM), and microbial biomass carbon (MB-C). The relative fractionation procedures have been developed, and the main research activities on SOM are transformed from the products of microorganisms (humus) to the organic matter comprised in plant residues at their various decomposition stages and the organic carbon in microorganisms, since they are biologically active and immediately respond to soil cultivation and tillage, crop rotation, and fertilizer application, etc.

Carbon↗
PubMed2004

[Proteins structure changes of COL4A5 gene point mutations and structure-phenotype relations in Alport syndrome].

OBJECTIVE: Alport syndrome (AS) is a progressive hereditary nephritis presented with hematuria and renal failure, frequently associated with sensorineural deafness and ocular lesions. So far, more than 300 gene mutations in AS have been identified which provides a better way to analyze the association between genotype and phenotype. It is hard to understand all the phenotype according to the gene mutations, because the structure and function changes of the relevant protein, alpha5(IV) chain, encoded by mutated COL4A5 gene are rare to know. This study aimed to detect the proteins structure encoded by COL4A5 gene with different missense mutations and to analyze the effect of gene mutations on the secondary structure of alpha5(IV) chain and structure-phenotype relations. METHODS: Two X-linked AS patients with different missense mutations (g.3246G > T resulting in p.G1015V and g.3290G > A resulting in p.G1030S, respectively) diagnosed by clinical manifestations, family history and skin or renal biopsy examinations, as well as a control were included in this study. The fragments of cDNA with the two mutations, respectively, and that of corresponding cDNA from the control were expressed in E. coli. The secondary structure of the recombinant polypeptides were analyzed by using circular dichroism (CD) spectroscopy. RESULTS: CD spectra of the control exhibited a negative peak near 200 nm whereas that of the patient 1 exhibited a negative peak near 220 nm. Furthermore, the magnitude of the negative peak of patient 1 decreased from -9000 deg x cm2 x dmol(-1) to -4000 deg x cm2 x dmol(-1) as compared with that of the control. CD spectra of the patient 2 were slightly changed with the negative peak remaining near 220 nm but the magnitude increasing from -9000 deg x cm2 x dmol(-1) to -11000 deg x cm2 x dmol(-1) as compared with that of the control. In addition, the secondary structure of the control polypeptide was mainly composed of beta-sheet and random coil without alpha-helix, whereas that of the patient 1 presented 12.9% alpha-helix. Although the secondary structure of polypeptide of the patient 2 was also mainly composed of beta-sheet and random coil, the composition of beta-sheet reduced and random coil increased. CONCLUSION: Although the glycine substitutions existed in the same domain of alpha5(IV) chain, the patient 1 with the severe AS phenotype and g.3246G > T mutation, and patient 2 with the mild AS phenotype and g.3290G > A mutation were revealed with different secondary structures of alpha5(IV) chain. Moreover, the secondary structure changes of alpha5(IV) chain were consistent with their corresponding phenotype severity.

Collagen Type IV↗
PubMed2004

Effects of amiloride on potassium and calcium currents in guinea pig ventricular myocytes.

AIM: To elucidate the possible mechanisms underlying antiarrhythmia of the non-selective Na+/H+ exchanger inhibitor--amiloride. METHODS: Single ventricular cells were isolated using a double-enzyme method. Effects of amiloride on voltage-dependent potassium and calcium currents in isolated guinea pig ventricular myocyte were recorded by using whole-cell patch clamp techniques. RESULTS: Exposure to amiloride (10 -100 micromol x L(-1)), the L-type and T-type calcium currents were depressed. Amiloride resulted in a concentration-dependent inhibition of peak (Ca,L), But amiloride did not change the shape of their I - V curves. It only decreased the amplitudes of the currents of the two types. When myocytes were incubated with 100 micromol x L(-1) amiloride, I(Kr) was slightly depressed and I(Ks) did not change. Amiloride (1 - 100 micromol x L(-10) depressed I(K1) in a concentration-dependent manner. CONCLUSION: Amiloride depressed potassium and calcium currents, which may give support to its uses in some diseases of the cardiovascular system.

Amiloride↗
PubMed2004

[Etiological study on an outbreak of acute respiratory infection in children in Beijing].

OBJECTIVE: An outbreak of acute respiratory infections in children occurred in Beijing from November to December, 2002. To investigate the etiological agents of affected children who were in day care centers and primary schools. METHODS: Throat swab specimens were collected from one primary school children with acute respiratory infections visiting one outpatient department. After centrifuging, supernatant from the specimens were inoculated into MDCK and Hep-2 cells for virus isolation and pallets for viral antigen detection and using indirect immunofluorescent assay on common respiratory viruses. Nested polymerase chain reaction was used at the same time for detection of respiratory viruses and Mycoplasma pneumoniae (Mp). RESULTS: A total number of 80 specimens were collected during the outbreak. Among them influenza B virus were detected from 18 specimens, with a positive rate of 22.5% (18/80) while Mp were detected from 13 specimens, with a positive rate of 16.3% (13/80). Influenza A3 were also detected from 2 patients (2.5%, 2/80). However, influenza A1, RSV, adenovirus and parainfluenza viruses were not found from these specimens. Influenza B virus and Mp were detected simultaneity in two specimens and influenza A3 virus and Mp were detected in one specimen. CONCLUSION: The outbreak of acute respiratory infection in children during the period of investigation was caused by both influenza B virus and Mp.

Adolescent↗
PubMed2004

[Polymorphisms on 15 STR loci of Han population in Yan'an].

OBJECTIVE: To investigate the polymorphisms of 15 STR loci of Han population in Yan'an. METHODS: Blood samples were obtained from 100 unrelated Han individuals in Yan'an. DNA templates were screened by AmpF/STR Identifiler kit and ABI3100Avant DNA analyzer. RESULTS: The allele frequencies of 15 STR loci ranged from 0.005 to 0.550, and the genotype frequencies ranged from 0.010 to 0.310. The combined match probability was 2.5x10(-17) and combined EPP was 0.999999999. CONCLUSIONS: The 15 STR loci used in this study were highly polymorphic in Han population in Yan'an and suitable for population study and forensic cases in this region.

Alleles↗
PubMed2004

[Advances in studies of biological clock gene].

The circadian clock genes, which generate and control the running of the circadian rhythms, exist in organisms ranging from prokaryotes to mammals. The oscillator genes and its coding proteins compose the feedback loops of circadian system. The kind, number and regulating route of clock genes are characterized by living things at different evolution levels. The molecular mechanism of the run of circadian clock genes in cyanobacteria, neurospore, fruit fly, mouse and human being is introduced in this article.

Animals↗