Jianxin Tang

Preparation of TiO2/Ag colloids with ultraviolet resistance and antibacterial property using short chain polyethylene glycol

TiO(2)/Ag nano-antibacterial material was prepared at low temperature using polyethylene glycol (PEG-600) as reducing and stabilizing agent. The size and shape as well as the optical properties of the nano-materials were characterized with transmission electron microscopy (TEM) and UV-vis spectroscopy (UV-vis). The results showed that the average particle size of TiO(2) among these nano-materials was around 50-150 nm, and the average particle size of nano-silver was around 20 nm. Formation of Ag nano-particles on the surface of TiO(2) was confirmed by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), and the antibacterial activity was also investigated. By the antibacterial activity study and ultraviolet resistance test, it is noted that growth inhibition rates against E. coli was 99.99% as the concentration of nano-particles dispersion solution was 10 ppm, the minimum UV protective effect could be achieved as the concentration was 290 ppm.

Combined Effects Methylation of FHIT, RASSF1A and RARβ Genes on Non-Small Cell Lung Cancer in the Chinese Population

Epigenetic modifications of tumour suppressor genes are involved in all kinds of human cancer. Aberrant promoter methylation is also considered to play an essential role in development of lung cancer, but the pathogenesis remains unclear.We collected the data of 112 subjects, including 56 diagnosed patients with lung cancer and 56 controls without cancer. Methylation of the FHIT, RASSF1A and RAR-β genes in DNA from all samples and the corresponding gene methylation status were assessed using the methylation-specific polymerase chain reaction (PCR, MSP). The results showed that the total frequency of separate gene methylation was significantly higher in lung cancer compared with controls (33.9-85.7 vs 0 %) (p<0.01).Similar outcomes were obtained from the aberrant methylation of combinations of any two or three genes (p<0.01). There was a tendency that the frequency of combinations of any two or three genes was higher in stage I+II than that in stage III+IV with lung cancer. However, no significant difference was found across various clinical stages and clinic pathological gradings of lung cancer (p>0.05).These observations suggest that there is a significant association of promoter methylation of individual genes with lung cancer risk, and that aberrant methylation of combination of any two or three genes may be associated with clinical stage in lung cancer patients and involved in the initiation of lung cancer tumorigenesis. Methylation of FHIT, RASSF1A and RARβ genes may be related to progression of lung oncogenesis.

Association of 5'-CpG island hypermethylation of the FHIT gene with lung cancer in southern-central Chinese population

The promoter Methylation of the FHIT gene has been associated with susceptibility to different cancers, including a role in the early pathogenesis of lung cancer. We investigated the aberrant promoter methylation of FHIT in lung cancer in the Han population of southern-central China. Blood samples from 123 lung cancer patients of different clinical stage and histological grading and 105 healthy control samples were collected. Methylation-specific polymerase chain reaction (MSP) was performed to analyze the methylation status of FHIT. Aberrant promoter methylation of the FHIT gene was 34.15% (42/123) in cancer patients, but in none of the 105 controls. Significant association was found between the lung cancer cases and controls (OR=2.296; 95%CI=1.95-2.705; P

Taxonomy characterization and cadmium biosorption of fungus strain

Abstract The taxonomy characteriazation and cadmium (Cd) biosorption of the high Cd-resistant fungus M1 were investigated. The internal transcribed spacers (ITS) region and β -tubulin genes of the strain were amplified, sequenced and analyzed by molecular biology technology. The Cd biosorption assay was performed by shaking flask. Fourier transform infrared spectroscopy was used to analyze the mycelium. The similarity of gene sequences and phylogenetic trees show the very close relation between the strain and Paecilomyces lilacinus , and the fungus M1 was identified as P. Lilacinus . The initial pH 6 and Cd concentration about 100 mg/L are optimum. Zn and Mn have a little effect on the Cd biosorption of the strain, while Cu and Pb present obvious effects. FTIR analysis shows that the fungus adsorbs Cd by esters, anhydride, and amide. With the preferable absorption capacity, fungus M1 is considered to have good prospects in bioremediation.

Optimization for extracellular biosynthesis of silver nanoparticles by Penicillium aculeatum Su1 and their antimicrobial activity and cytotoxic effect compared with silver ions

The present study addresses an eco-friendly and energy-saving method for extracellular biosynthesis of silver nanoparticles (AgNPs) using a cell free filtrate of the fungus strain Penicillium aculeatum Su1 as a reducing agent. Parametric optimization of the biosynthesis process demonstrated different effects on the size, distribution, yield, and synthesis rate of biosynthesized AgNPs. The transmission electron microscopy (TEM) measurements demonstrated that AgNPs were spherical or approximately spherical, with a size between 4 and 55nm. High-resolution transmission electron microscopy (HR-TEM) and X-ray diffraction (XRD) analyses indicated that AgNPs were nanocrystalline by nature, with the character of a face-centered cubic (fcc). Fourier transform infrared spectroscopy (FTIR) analysis confirmed the existence of protein molecules that acted as a reducing agent and a capping agent during the biosynthesis process. Furthermore, the biosynthesized AgNPs exhibited higher antimicrobial activity than silver ions against Gram negative bacteria, Gram positive bacteria and fungi. Compared with silver ions, the biosynthesized AgNPs presented higher biocompatibility toward human bronchial epithelial (HBE) cells and high cytotoxicity in a dose-dependent manner with an IC50 of 48.73μg/mL toward A549 cells. These results demonstrate that Penicillium aculeatum Su1 is a potential bioresource that can be used to produce low-cost and eco-friendly AgNPs as efficient antimicrobial agent, drug delivery vehicle or anticancer drug for clinic treatment.

Association of Methylation of the RAR-β Gene with Cigarette Smoking in Non-Small Cell Lung Cancer with Southern-central Chinese Population

Pathogenesis of lung cancer is a complicated biological process including multiple genetic and epigenetic changes. Since cigarette smoking is confirmed as the most main risk factor of non-small cell lung cancer (NSCLC), the aim of this study was to determine whether tobacco exposure plays a role in gene methylation. Methylation of the RAR-β gene were detected using methylation-specific polymerase chain reaction in DNA from 167 newly diagnosed cases with NSCLC and corresponding 105 controls. A significant statistical association was found in the detection rate of the promoter methylation of RAR-β gene between NSCLC and controls (x2=166.01; p<0.01), and hypermethylation of the RAR-β gene was significantly associated with smoking status (p=0.038, p<0.05). No relationship was found between RAR-β gene methylation and pathologic staging including clinical stage, cell type, gender and drinking (p>0.05), and the methylation of RAR-β gene rate of NSCLC was slightly higher in stages III+IV (80.0%) than in I+II (70.8%). Similar results were obtained for methylation of the RAR-β gene between squamous cell carcinoma (77.9%) and other cell type lung cancer (73.9%). These results showed that the frequency of methylation increased gradually with the development of clinical stage in smoking-associated lung cancer patients, and tobacco smoke may be play a potential role in RAR-β gene methylation in the early pathogenesis and process in lung cancer, particularly squamous cell carcinoma. Aberrant promoter methylation is considered to be a promising marker of previous carcinogen exposure and cancer risk.

Association between a p73 Gene Polymorphism and Genetic Susceptibility to Non-small Cell Lung Cancer in the South of China

BACKGROUND This study aimed to identify any association between the p73 gene G4C14-to-A4T14 polymorphism and risk of non-small cell lung cancer (NSCLC) in the south of China. MATERIALS AND METHODS We genotyped the p73 gene polymorphism of peripheral blood DNA from 168 patients with NSCLC and 195 normal controls using HRM (high resolution melting) and PCR-CTPP (polymerase chain reaction with confronting two-pair primers). RESULTS The results of genotyping by HRM and PCR-CTPP were consistent with direct sequencing, the p73 genotype distribution in 168 lung cancer patients being as follows: GC/GC 101 cases (60.1%), GC/ AT 59 cases (35.1%), AT/AT 8 cases (4.8%). The carriers of AT/AT genotype had a significantly reduced risk of NSCLC (OR=0.370; 95%CI: 0.170-0.806; p=0.010) as compared with non-carriers. However, we found no relations between p73 genotypes and histological type (p=0.798, x2=0.452), tumor stage (p=0.806, x2=0.806), or lymph node metastasis (p=0.578, x2=1.098). CONCLUSIONS Our findings suggest that the p73 G4C14-to-A4T14 polymorphism may be a modifier of NSCLC susceptibility in the Chinese population.

Isolation, genetic identification and degradation characteristics of COD-degrading bacterial strain in slaughter wastewater

Contamination of water by meat production is an important and extensive environmental problem and even threat to human health. Biodegradation is a major mechanism which removes the pollutants from the environment. Therefore, the present study aimed to isolate and characterize a COD degrading bacteria which can effectively degrade slaughter wastewater. Six COD degrading bacteria were isolated from slaughtering waste water and sludge in Hunan a meat product Co., Ltd. And the COD degradation rate of each strain was determined by potassium permanganate method. Through observing morphologically and analyzing sequence to 16S rDNA, the highest COD degradation strain was Bacillus velezensis by preliminarily identified and classified, reaching 11.80%. The suitable conditions of the growth of Bacillus velezensis strain were 37 °C, pH 7.0, the peptone concentration 1.5%, and the yeast extract concentration 0.8%.

Extracellular Biosynthesis, Characterization and Cytotoxic Effect of Silver Nanoparticles by Streptomyces coelicoflavus KS-3

The present work aimed to investigate extracellular biosynthesis of silver nanoparticles (AgNPs) mediated by an actinomycete strain and their cytotoxic effects compared with silver ions. The selected strain was identified as Streptomyces coelicoflavus KS-3 by phenotypical characteristics and 16S rRNA analysis. The formation of biosynthesized AgNPs was proved by an absorption peak observed at 437 nm. Transmission electron microscopy (TEM) and dynamic light scattering (DLS) analyses revealed that the prepared AgNPs were spherical or approximately spherical followed by a small amount of truncated triangular, quadrangular and hexagonal with the particle diameters ranging from 2.33 to 91.3 nm. X-ray diffraction (XRD) pattern confirmed that the AgNPs presented a face-centered cubic (FCC) structure of crystalline silver. Energy dispersive of X-ray (EDX) spectrum and Fourier transform infrared spectroscopy (FTIR) analyses verified the existence of biomolecules, such as proteins, that participated in the formation and stabilization of AgNPs. Furthermore, the comparative study on cytotoxic effect of AgNPs indicated that the AgNPs exhibited higher biocompatibility towards human bronchial epithelial (HBE) cells than silver ions and exerted potent cytotoxic effect in a dose-dependent manner against human lung squamous cell carcinoma cells (HTB-182) and human lung adenocarcinoma cells (A549) with the concentrations ranging from 1 to 50 μg/mL.