Biomedical subjects

Jian-Hua Wang

Publications and source records attributed to Jian-Hua Wang.

At least 19 recordsLinked to original sources

PubMed2007

Multimerization and fusion expression of bovine lactoferricin derivative LfcinB15-W4,10 in Escherichia coli.

Antimicrobial peptides are promising candidates for therapeutic and industrial application owing to their broad spectrum. In this work, a cost-effective method for expression of a potent antimicrobial peptide, bovine lactoferricin derivative LfcinB15-W4,10, has been developed. The oligonucleotide encoding the peptide was linked to generate different oligomeric oligonucleotide segments containing from one to nine but eight tandem copies which was inserted individually to the E. coli expression vector pET32a. The thioredoxin fusion peptides were successfully expressed and detected with different molecular weight on SDS gel, respectively. Among the monomer and other multimeric peptides, the tetramer was expressed at the highest level. After purification, more than 10 mg of tetramer with 99% purity was obtained from 1 l culture and exhibited similar antimicrobial activity as synthetic LfcinB15-W4,10 monomer. The expression system in this study provides a potential production method for lactoferricin derivatives and other antimicrobial peptides in research and industrial applications.

Animals↗

PubMed2007

Direct extraction of double-stranded DNA into ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate and its quantification.

Ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate (BmimPF6), as a green solvent, was successfully used for the direct extraction of dsDNA. The extraction efficiency and the distribution coefficient values indicated that trace amounts of DNA at the levels of <5 ng microL-1 facilitate quantitative fast extraction, while proteins and metal species do not interfere. A total of 30% of the DNA in ionic liquid at approximately 20 ng microL-1 was back extracted into aqueous phase in phosphate-citrate buffer with a single-stage extraction. The extraction is demonstrated to be endothermic with an enthalpy of 34.3 kJ moL-1. The extraction mechanisms were proposed and verified by 31P NMR and FT-IR spectra. Interactions between cationic 1-butyl-3-methylimidazolium (Bmim+) and P-O bonds of phosphate groups in the DNA strands take place both in the dissolved BmimPF6 in aqueous phase and at the interface of the two phases. This interaction consequently led to the transformation of DNA conformations, along with a reduction of ethidium resonance light scattering at 510 nm, and a procedure for DNA quantification in ionic liquid was developed based on this observation.

Cations↗

PubMed2007

Codon optimization of Bacillus licheniformis beta-1,3-1,4-glucanase gene and its expression in Pichia pastoris.

Beta-1,3-1,4-glucanase (EC3.2.1.73) as an important industrial enzyme has been widely used in the brewing and animal feed additive industry. To improve expression efficiency of recombinant beta-1,3-1,4-glucanase from Bacillus licheniformis EGW039(CGMCC 0635) in methylotrophic yeast Pichia pastoris GS115, the DNA sequence encoding beta-1,3-1,4-glucanase was designed and synthesized based on the codon bias of P. pastoris, the codons encoding 96 amino acids were optimized, in which a total of 102 nucleotides were changed, the G+C ratio was simultaneously increased from 43.6 to 45.5%. At shaking flask level, beta-1,3-1,4-glucanase activity is 67.9 and 52.3 U ml(-1) with barley beta-glucan and lichenan as substrate, respectively. At laboratory fermentor level, the secreted protein concentration is approximately 250 mg l(-1). The beta-1,3-1,4-glucanase activity is 333.7 and 256.7 U ml(-1) with barley beta-glucan and lichenan as substrate, respectively; however, no activity of this enzyme on cellulose is observed. Compared to the nonoptimized control, expression level of the optimized beta-1,3-1,4-glucanase based on preferred codons in P. pastoris shown a 10-fold higher level. The codon-optimized enzyme was approximately 53.8% of the total secreted protein. The optimal acidity and temperature of this recombinant enzyme were pH 6.0 and 45 degrees C, respectively.

Bacillus↗

PubMed2007

Extraction of proteins from biological fluids by use of an ionic liquid/aqueous two-phase system.

An ionic liquid/aqueous two-phase system based on the hydrophilic ionic liquid 1-butyl-3-methylimidazolium chloride (BmimCl) and K(2)HPO(4) has been employed for direct extraction of proteins from human body fluids for the first time. Proteins present at low levels were quantitatively extracted into the BmimCl-rich upper phase with a distribution ratio of about 10 between the upper and lower phase and an enrichment factor of 5. Addition of an appropriate amount of K(2)HPO(4) to the separated upper phase results in a further phase separation, giving rise to an improved enrichment factor of 20. FTIR and UV spectroscopy demonstrated that no chemical (bonding) interactions between the ionic liquid and the protein functional groups were identifiable, while no alterations of the natural properties of the proteins were observed. The partitioning of proteins in the two-phase system was assumed to have been facilitated by the electrostatic potential difference between the coexisting phases, as well as by salting out effects. The system could be applied successfully for the quantification of proteins in human urine after on-line phase separation in a flow system. The use of an ionic liquid, as a green solvent, offers clear advantages over traditional liquid-liquid extractions, in which the use of toxic organic solvents is unavoidable.

Biochemistry↗

PubMed2006

Utilizing generalized autocalibrating partial parallel acquisition (GRAPPA) to achieve high-resolution contrast-enhanced MR angiography of hepatic artery: initial experience in orthotopic liver transplantation candidates.

OBJECTIVE: To evaluate feasibility of using GRAPPA to acquire high-resolution 3D contrast-enhanced MR angiography (CE-MRA) of hepatic artery and value of GRAPPA for displaying vessels anatomy. MATERIALS AND METHODS: High-resolution CE-MRA using GRAPPA was performed in 67 orthotopic liver transplantation recipient candidates. Signal intensity (SI) and relative SI, i.e., Cv-ro (vessel-to-liver contrast) of the aorta and the hepatic common artery (HCA), were measured. The SI and the relative SI were compared and analyzed using T-test. For purpose of qualitative evaluation, the vessel visualization quality and the order of depicted hepatic artery branches were evaluated by two radiologists independently and assessed by weighted kappa analysis. The depiction of hepatic arterial anatomy and variations was evaluated, and results were correlated with the findings in surgery. RESULTS: The mean SI values were 283.29+/-65.07 (mean+/-S.D.) for aorta and 283.16+/-64.07 for HCA, respectively. The mean relative SI values were 0.698+/-0.09 for aorta and 0.696+/-0.09 for HCA, respectively. Homogeneous enhancement between aorta and HCA was confirmed by statistically insignificant differences (p-values were 0.89 for mean SI values and 0.12 for mean relative SI values, respectively). The average score for vessel visualization ranged from good to excellent for different artery segments. Overall interobserver agreement in the visualization of different artery segments was excellent (kappa value>0.80). The distal intrahepatic segmental arteries were well delineated for majority of patients with excellent interobserver agreement. Normal hepatic arterial anatomy was correctly demonstrated in 53 patients, and arterial anomalies were accurately detected on high-resolution MRA image of all 14 patients. CONCLUSION: High-resolution hepatic artery MRA acquired using GRAPPA in a reproducible manner excellently depicts and delineates small vessels and can be routinely used for evaluating OLT candidates.

Adult↗

PubMed2006

CD4 coexpression regulates DC-SIGN-mediated transmission of human immunodeficiency virus type 1.

Dendritic cells (DCs) potently stimulate the cell-cell transmission of human immunodeficiency virus type 1 (HIV-1). However, the mechanisms that underlie DC transmission of HIV-1 to CD4(+) T cells are not fully understood. DC-SIGN, a C-type lectin, efficiently promotes HIV-1 trans infection. DC-SIGN is expressed in monocyte-derived DCs (MDDCs), macrophage subsets, activated B lymphocytes, and various mucosal tissues. MDDC-mediated HIV-1 transmission to CD4(+) T cells involves DC-SIGN-dependent and -independent mechanisms. DC-SIGN transmission of HIV-1 depends on the donor cell type. HIV-1 Nef can upregulate DC-SIGN expression and promote DC-T-cell clustering and HIV-1 spread. Nef also downregulates CD4 expression; however, the effect of the CD4 downmodulation on DC-mediated HIV-1 transmission has not been examined. Here, we report that CD4 expression levels correlate with inefficient HIV-1 transmission by monocytic cells expressing DC-SIGN. Expression of CD4 on Raji B cells strongly impaired DC-SIGN-mediated HIV-1 transmission to T cells. By contrast, enhanced HIV-1 transmission was observed when CD4 molecules on MDDCs and DC-SIGN-CD4-expressing cell lines were blocked with specific antibodies. Coexpression of CD4 and DC-SIGN in Raji cells promoted the internalization and intracellular retention of HIV-1. Interestingly, internalized HIV-1 particles were sorted and confined to late endosomal compartments that were positive for CD63 and CD81. Furthermore, in HIV-1-infected MDDCs, significant downregulation of CD4 by Nef expression correlated with enhanced viral transmission. These results suggest that CD4, which is present at various levels in DC-SIGN-positive primary cells, is a key regulator of HIV-1 transmission.

Antibodies, Monoclonal↗

PubMed2006

Whole-body three-dimensional contrast-enhanced magnetic resonance (MR) angiography with parallel imaging techniques on a multichannel MR system for the detection of various systemic arterial diseases.

Using a 1.5-T magnetic resonance (MR) imager equipped with 32 receiving channels and integrated parallel acquisition techniques, 37 patients underwent whole-body three-dimensional (3D) contrast-enhanced MR angiography (WB 3D CE MRA). The patients included had clinically documented or suspected peripheral arterial occlusive disease (PAOD, n = 19), Takayasu arteritis (n = 8), polyarteritis nodosa (n = 1), type-B dissection (n = 4), thoracic and/or abdominal aneurysm (n = 5). Sixty-eight surface coils were employed to encompass the whole body. Four 3D CE MRA stations were acquired successively through automatic table moving. The spatial resolution was 1.6 x 1.0 mm and slice thickness was 1.5 mm for all stations. A total scan range of 188 cm was acquired. Overall image quality of each arterial segment and venous overlay were assessed. The depiction of various systemic arterial diseases was evaluated and compared, in 20 patients, with other imaging modalities. This WB 3D CE MRA yielded a detailed display of the arterial system with an average MR room time of 17.4 min. The image quality was considered diagnostic in 99.3% of the arterial segments. In 7 of 19 patients with PAOD, WB MRA showed additional vascular narrowing apart from peripheral arterial disease. In nine patients with vasculitis, WB MRA depicted luminal irregularity, narrowing or occlusion, aneurysm, and collateral circulation involving multiple vascular segments. WB MRA also clearly revealed the severity and extent of dissection and aortic aneurysm. In 20 cases where additional imaging investigations have been carried out, the vascular pathologies demonstrated by WB MRA agree with these additional imaging investigations.

Adolescent↗

PubMed2006

Role of ethanol in the regulation of hepatic stellate cell function.

Evidence has accumulated to suggest an important role of ethanol and/or its metabolites in the pathogenesis of alcohol-related liver disease. In this review, the fibrogenic effects of ethanol and its metabolites on hepatic stellate cells (HSCs) are discussed. In brief, ethanol interferes with retinoid metabolism and its signaling, induces the release of fibrogenic cytokines such as transforming growth factor beta-1 (TGFbeta-1) from HSCs, up-regulates the gene expression of collagen I and enhances type I collagen protein production by HSCs. Ethanol further perpetuates an activated HSC phenotype through extracellular matrix remodeling. The underlying pathophysiologic mechanisms by which ethanol exerts these pro-fibrogenic effects on HSCs are reviewed.

Animals↗

PubMed2006

Lab-on-valve system integrating a chemiluminescent entity and in situ generation of nascent bromine as oxidant for chemiluminescent determination of tetracycline.

A novel configuration of a lab-on-valve (LOV) system was fabricated and applied for chemiluminescence (CL) detection by integrating a demountable Z-type flow cell onto the LOV unit. A bismuthate immobilized microcolumn was incorporated in one port of the LOV for in situ oxidation of KBr and generation of bromine as oxidant for the bromine-hydrogen peroxide-tetracycline (TC) chemiluminescent reaction. The nascent bromine reacts with hydrogen peroxide and produces a weak CL signal, the intensity of which was significantly enhanced in the presence of TC following an energy-transfer mechanism. A novel procedure for tetracycline quantification was therefore developed based on the present system. When compared with the reported flow injection-CL methods for TC, this procedure not only provided an improved detection limit of 2.0 microg L(-)(1) but also minimized sample and reagent consumption. A linear range of 6.0-10 000 microg L(-)(1) was derived along with RSD values of 5.9 (at the concentration level of quantification limit) and 2.2% (at 50 microg L(-)(1)), and a sampling frequency of 120 h(-)(1) was achieved. The system was validated with a National Standard Procedure (GB/T 18932.4-2002, HPLC with UV detection) by measuring TC contents in commercial milk samples.

Bromine↗

PubMed2006

A sequential injection fluorometric procedure for the determination of procaine in human blood and pharmaceuticals.

An automated procedure for the assay of procaine hydrochloride in human blood and pharmaceuticals was developed using a sequential injection (SI) technique with fluorometric detection and fluorescamine as the fluorescence probe. A few microliters of fluorescamine and procaine hydrochloride solutions were used in the SI system leading to the formation of a derivative, which was then excited by a 400-nm LED and whose emitted fluorescence was monitored at a wavelength of 494 nm. A linear calibration graph was obtained with 10-200 ng mL(-1) (procaine) by loading 10.0 microL of sample solution and 5.0 microL of fluorescamine solution (both 0.125 % m/v). A detection limit of 2.6 ng mL(-1), defined as 3 times the blank standard deviation (3sigma), was achieved along with a sampling frequency of 25 h(-1) and a precision of 2.1 % RSD at the 50.0 ng mL(-1) level. Procaine contents in injection solutions from various pharmaceutical manufactures were analyzed and reasonable agreement was achieved between the values obtained by using the present procedure and the documented spectrophotometry, and both were coincident with the nominal concentrations. In addition, the degradation of procaine in human blood was investigated. A fast degradation of procaine in human blood was observed for the first 30 min, while afterwards the degradation was retarded.

Buffers↗

PubMed2006

Determination of multiclass pesticide residues in apple juice by gas chromatography-mass spectrometry with large-volume injection.

This study presents two GC-MS SIM methods, in combination with large-volume injection programmed-temperature vaporization (LVI-PTV) injection, for the determination of 141 pesticide residues in apple juice. The sample was extracted with ACN, and coextractives were removed with primary/secondary amine sorbent. ACN extract (20 microL) was injected into a PTV injection port in solvent vent mode, and the pesticides were determined by GC-MS using retention time locking software. Deuterium-labeled pesticides (surrogate standards) were used for analytical quality control. In the validation experiments, pesticides recoveries were found to be 70-121% with RSDs of 4.6-21% (n = 6).

Beverages↗

PubMed2006

Pick's disease with Pick bodies combined with progressive supranuclear palsy without tuft-shaped astrocytes: a clinical, neuroradiologic and pathological study of an autopsied case.

We report clinical, neuroradiologic features, and neuropathologic findings of a 76-year-old man with coexistent Pick's disease and progressive supranuclear palsy. The patient presented with loss of recent memory, abnormal behavior and change in personality at the age of 60. The symptoms were progressive. Three years later, repetitive or compulsive behavior became prominent. About 9 years after onset, he had difficulty moving and became bedridden because of a fracture of his left leg. His condition gradually deteriorated and he developed mutism and became vegetative. The patient died from pneumonia 16 years after the onset of symptoms. Serial MRI scans showed progressive cortex atrophy, especially in the bilateral frontal and temporal lobes. Macroscopic inspection showed severe atrophy of the whole brain, including cerebrum, brainstem and cerebellum. Microscopic observations showed extensive superficial spongiosis and severe neuronal loss with gliosis in the second and third cortical layers in the frontal, temporal and parietal cortex. There were Pick cells and argyrophilic Pick bodies, which were tau- and ubiquitin-positive in neurons of layers II-III of the above-mentioned cortex. Numerous argyrophilic Pick bodies were observed in the hippocampus, especially in the dentate fascia. In addition, moderate to severe loss of neurons was found with gliosis and a lot of Gallyas/tau-positive globus neurofibrillary tangles in the caudate nucleus, globus pallidus, thalamus, substantia nigra, locus coeruleus and dentate nucleus. Numerous thorned-astrocytes and coiled bodies but no-tuft shaped astrocytes were noted in the basal ganglion, brainstem and cerebellar white matter. In conclusion, these histopathological features were compatible with classical Pick's disease and coexistence with progressive supranuclear palsy without tuft-shaped astrocytes.

Aged↗

PubMed2006

A new treatment strategy for severe arthrofibrosis of the knee. A review of twenty-two cases.

BACKGROUND: To reduce the morbidity of traditional quadricepsplasty for the treatment of severe arthrofibrosis of the knee, we instituted a treatment regimen consisting of an initial extra-articular mini-invasive quadricepsplasty and subsequent intra-articular arthroscopic lysis of adhesions during the same anesthesia session. The purpose of the present study was to determine the results of this technique. METHODS: From 1998 to 2001, twenty-two patients with severely arthrofibrotic knees were managed with this operative technique. The mean age of the patients at the time of the operation was thirty-seven years. After a mean duration of follow-up of forty-four months (minimum, twenty-four months), all patients were evaluated according to the criteria of Judet and The Hospital for Special Surgery knee-rating system. RESULTS: The average maximum degree of flexion increased from 27 degrees preoperatively to 115 degrees at the time of the most recent follow-up (p < 0.001). According to the criteria of Judet, the result was excellent for sixteen knees, good for five, and fair for one. The average Hospital for Special Surgery knee score improved from 74 points preoperatively to 94 points at the time of the most recent follow-up (p < 0.001). A superficial wound infection occurred in one patient. Only one patient had a persistent 15 degrees extension lag. CONCLUSIONS: This mini-invasive operation for the severely arthrofibrotic knee can be used to increase the range of motion and enhance functional outcome.

Adolescent↗

PubMed2006

[Protective effect of hyperin on focal cerebral ischemia reperfusion injury in rats].

OBJECTIVE: To investigate the protective effect of hyperin (Hyp) on focal cerebral ischemia reperfusion injury in rats. METHODS: Sixty Wistar male rats were randomly divided into sham-operated group, untreated group, and high-, medium- and low-dose Hyp-treated groups (50, 25 and 12.5 mg x kg(-1) x d(-1)) and ginkgo leaf-treated group. The animals were intragastrically administered with drugs for 5 days. Thirty minutes after the end administration, the operation was performed to induce the middle cerebral artery occlusion (MCAO) model in rats with the method of intraluminal thread. The middle cerebral artery blood flow was blocked for 2 hours, and then reperfused. Twenty-four hours later, the rats' neurology score was observed. Brain triphenyltetrazolium chloride (TTC) staining and dried wet method were carried out to measure the infarct size and the water content of rat brain tissue respectively. RESULTS: The above-mentioned indexes in the untreated group showed significant differences compared with those in the sham-operated group (P<0.01).The infarct sizes of rat brain tissue in the high- and medium-dose Hyp-treated groups were obviously decreased compared with that in the untreated group (P<0.01, P<0.05). The water content of rat brain and the neurology score were also obviously reduced compared with those in the untreated group (P<0.05 or P<0.01). CONCLUSIONS: Hyp could obviously reduce the brain infarct size and cerebral edema degree in focal cerebral ischemia reperfusion injury rats. Hyp has significant protective effect on focal cerebral ischemia reperfusion injury.

Animals↗

PubMed2006

[Phase II clinical trial of home-produced Nedaplatin in treating advanced esophageal carcinoma].

BACKGROUND & OBJECTIVE: Nedaplatin is a second-generation anticancer drug containing organic platinum. Clinical researches in overseas showed that Nedaplatin is an anticancer drug with broad spectrum and high efficiency, especially in treating esophageal carcinoma. But the therapeutic efficacy and toxicity of home-produced Nedaplatin in China are unclear. This study was to evaluate the efficacy of home-produced Nedaplatin in China on esophageal carcinoma, and observe its toxicity. METHODS: A multi-center, phase II, prospective clinical trial was conducted. Naive patients with esophageal carcinoma were enrolled and randomized into trial group and control group. The patients in trial group were treated with home-produced Nedaplatin plus 5-fluorouracil (5-FU); the patients in control group were treated with cisplatin (DDP) plus 5-FU. RESULTS: A total of 52 patients were enrolled: 30 in trial group, and 22 in control group. For trial group, therapeutic efficacy was evaluable in 27 cases, and toxicity was evaluable in all cases; for control group, therapeutic efficacy and toxicity were evaluable in all cases. The response rate was significantly higher in trial group than in control group (29.62% vs. 22.72%, P<0.05). The complete remission (CR) rates were 18.51% in trial group and 4.55% in control group. When considering myelosuppression, the occurrence rate of anemia was similar in the 2 groups; but the occurrence rates of neutropenia and thrombocytopenia were higher in trial group than in control group, especially for grade III-IV thrombocytopenia (20.68% vs. 0%, P<0.01). The occurrence rate of gastrointestinal reaction was lower in trial group than in control group. There were no significant differences in hepatotoxicity, renal toxicity, heart toxicity, peripheral nerve toxicity, and alopecia between the 2 groups. CONCLUSIONS: Nedaplatin is an effective platinum drug for esophageal carcinoma. The treatment efficacy of Nedaplatin plus 5-FU regimen is better than that of DDP plus 5-FU regimen. It has a good clinical tolerance. The main toxicity is myelosuppression, and thrombocytopenia is predominant.

Adult↗

PubMed2005

A beta-galactose-specific lectin isolated from the marine worm Chaetopterus variopedatus possesses anti-HIV-1 activity.

A 30 kDa beta-galactose-specific lectin named CVL was isolated from the polychaete marine worm Chaetopterus variopedatus (Annelida) and its anti-HIV-1 activity in vitro was determined. Results showed that CVL inhibited cytopathic effect induced by HIV-1 and the production of viral p24 antigen. The EC(50) values were 0.0043 and 0.057 microM, respectively. Time-of-addition analysis of anti-HIV-1 activity indicated its action was at the early stage of virus replication. CVL could blocked the cell-to-cell fusion process of HIV infected and uninfected cells with an EC(50) of 0.073 microM. The inhibition of HIV-1 entry into host cells was demonstrated by using fluorescence-based real-time quantify PCR. At CVL concentration of 0.33 microM and 0.07 microM, 86% and 21% virus attachment were blocked, respectively. The anti-HIV-1 action of CVL might relate to blockade of HIV-1 entry into cells.

Animals↗

PubMed2005

Consideration of role of radiotherapy for lymph node metastases in patients with HCC: retrospective analysis for prognostic factors from 125 patients.

OBJECTIVES: To evaluate the role of radiotherapy (RT) for hepatocellular carcinoma (HCC) patients with abdominal lymph node (LN) metastasis at our institution in the past 7 years. METHODS AND MATERIALS: We identified 125 patients with HCC metastasis to regional LNs treated with or without external beam RT (EBRT) between 1998 and 2004. Clinical characteristics collected included alpha-fetoprotein status, gamma-glutamyltransferase, status of intrahepatic tumors (size and number), previous therapy for intrahepatic tumors, metastatic LN status (location, number, and size), tumor thrombi, and Child-Pugh classification. Of the 125 patients, 62 received local limited EBRT and were classified as the EBRT group. They received locoregional LN irradiation. The tumor dose ranged from 40 to 60 Gy in daily 2.0-Gy fractions, 5 times weekly. Another 63 patients, who did not receive EBRT, were selected from hospitalized patients in the same period and were classified as the non-EBRT group. The parameters studied included survival rates and tumor response to EBRT both as demonstrated by clinical symptoms and as seen on CT. The Kaplan-Meier method was used to evaluate the survival rates, and the Cox regression model was used to identify predictors of outcome. RESULTS: After EBRT, partial responses and complete responses were observed in 37.1% and 59.7% of patients, respectively. The median survival was 9.4 months (95% confidence interval 5.8-13.0) for the EBRT group and 3.3 months (95% confidence interval, 2.7-3.9) for the non-EBRT group (p < 0.001). Multivariate analysis showed that multiple intrahepatic primary tumors, occurrence of tumor thrombi, no therapy for intrahepatic tumors, and greater Child-Pugh classification were related to a poorer prognosis in all patients. In the EBRT group, the survival periods decreased as the distance of LN involvement from the liver increased (following the natural flow of lymph) and was also associated with the intrahepatic primary tumor size. The incidence of death resulting from LN-related complications was lower in the EBRT group. CONCLUSION: Lymph node metastasis from HCC is sensitive to EBRT. EBRT with 25 fractions of 2 Gy is an effective palliative treatment for patients with LN metastases from HCC presenting with good performance status and may prolong overall survival.

Adult↗

PubMed2005

A novel heme-containing protein with anti-HIV-1 activity from skin secretions of Bufo andrewsi.

A novel protein, named BAS-AH, was purified and characterized from the skin of the toad Bufo andrewsi. BAS-AH is a single chain protein and the apparent molecular weight is about 63 kDa as judged by SDS-PAGE. BAS-AH was determined to bind heme (0.89 mol heme/mol protein) as determined by pyridine haemochrome analysis. Fifty percentage cytotoxic concentration (CC50) of BAS-AH on C8166 cells was 9.5 microM. However, at concentrations that showed little effect on cell viability, BAS-AH displayed dose dependent inhibition on HIV-1 infection and replication. The antiviral selectivity indexes (CC50/EC50) were 14.4 and 11.4, respectively, corresponding to the measurements of syncytium formation and HIV-1 p24 antigen expression. BAS-AH also showed an inhibitory effect on the activity of recombinant HIV-1 reverse transcriptase (IC50 = 1.32 microM). The N-terminal sequence of BAS-AH was determined to be NAKXKADVIGKISILLGQDNLSNIVAAM, which exhibited little identity with other known anti-HIV-1 proteins. BAS-AH is devoid of antibacterial, proteolytic, trypsin inhibitory activity, l-amino acid oxidase activity and catalase activity.

Amino Acid Sequence↗