Evaluation of Biological Characteristics of Bacteria Contributing to Biofilm Formation

Biofilm-associated microorganisms play crucial roles in terrestrial and aquatic nutrient cycling and in the biodegradation of environmental pollutants. Biofilm formation was determined for a total of 18 bacterial isolates obtained from the biofilms of wastewater treatment systems and of little carpolite in soil. Among these isolates, seven showed strong biofilm-forming capacity. The phylogenetic affiliation of the isolates showing high biofilm formation capacity was determined through 16S rDNA sequencing and the isolates were grouped into 7 bacterial species including Pseudornonas sp., Pseudomonas putida, Aeromonas caviae, Bacillus cereus, Pseudornonas plecoglossicida, Aeromonas hydrophila, and Comamonas testosteroni. The biofilm-forming capacity was closely related with flagella, exopolysaccharide, and extracellular protein. According to the coefficient of determination, the relative importance of the five biological characteristics to biofilm formation was, in order from greatest to least, exopolysaccharide 〉 flagella 〉 N-acyl-homoserine lactones （AHLs） signaling molecules 〉 extracellular protein 〉 swarming motility.

Electrochemical methods for the characterization and interfacial study of dye-sensitized solar cell

Dye-sensitized solar cell （DSSC） is one of the most rapidly developed solar cells in the past 20 years. Many characterization methods have been employed for further understanding the operational details of the photo- electric conversion in DSSC as well as the evaluation of cell performance. Electrochemical methods have become pow- erful tools for studying the charge transfer and interfacial process. In this review, we introduce and explain the various electrochemical methods used to characterize and analyze DSSC, including current-voltage （I-V） scan measurement, cyclic voltammetry, electrochemical impedance spec- troscopy, intensity-modulated photocurrent spectroscopy, and intensity-modulated photovoltage spectroscopy. In ad- dition, some applications were provided as samples to elucidate electron transfer kinetics, energy levels and electrocatalytic activity of the materials used in DSSC.

ESTABLISHMENT AND CHARACTERIZATION OF TWO CELL LINES DERIVED FROM HUMAN TRANSITIONAL CELL CARCINOMA

Two continuous cell lines derived from the neoplastic urothelium had been maintained in culture for more than two years. The first cell line derived from the urothelium of a fusion papillocarcinoma on the left lateral wall of the bladder was designated as TBC-1 and grown in vitro for more than 150 generations. The second cell line derived from the urothelium of a papillocarcinoma in the left renal pelvis was designated as TPC-1 and grown in vitro for more than 100 generations. Characterization studies made on both cell lines showed that the cells had a rapid doubling time, exhibited mul-tilayering and produced tumors in sc of BALB / c. Tumor nodules that produced sc of BALB / c kept similar cellular and pathological features to those of the primary biopsy specimens under light and electron microscopes. TPC-1 cell line exhibited a three-dimensional structure of transitional epithelium on the nylon-mesh disk which was coated with a layer of rat tail collagen. Both TBC-1 and TPC-1 cell lines formed colonies in soft agar. Their forming rates were 35% and 28%, respectively. The chromosome number of TBC-1 cells ranged from 17 to 84, with a modal number of 54; whereas that of TPC-1 cells ranged from 28 to 139, with a modal number of 49. The TBC-1 cells showed mutant p53 and ras p21 protein expression and expressed weakly ABH blood group isoantigens. Analysis of lactic dehydrogenase (LDH) isozymes showed the highest levels of LDH isozyme 4 sonicated cell lysates of TBC-1 and TPC-1 respectively.

Biological character of human adipose-derived adult stem cells and influence of donor age on cell replication in culture

To investigate the biological character of human adipose-derived adult stem cells (hADAS cells) when cultured in vitro and the relationship between hADAS cell’s replication activity and the donor’s age factor, and to assess the stem cells as a new source for tissue engineering. hADAS cells are isolated from human adipose tissue of different age groups (from adolescents to olds: <20 years old, 21―40 years old, 41―60 years old and >61 years old groups). The protein markers (CD29, CD34, CD44, CD45, CD49d, HLA-DR, CD106) of hADAS cells were detected by flow cytometry (FCM) to identify the stem cell, and the cell cycle was examined for P20 hADAS cells to evaluate the safety of the subculture in vitro. The generative activity of hADAS cells in different age groups was also examined by MTT method. The formula “ log2T D = t logN t ? logN 0” was used to get the time doubling (TD) of the cells. The results showed that the cells kept heredity stabilization by chromosome analysis for at least 20 passages. The TD of these cells increased progressively by ageing, and the TD of the <20 years old group was lower than that of the >61 years old group (statistical analysis of variance (ANOVA), P=0.002, P<0.05). These find- ings suggested that a higher level of hADAS cells replication activity was found in the younger dona- tors, and they represent novel and valuable seed cells for studies of tissue engineering.