Genomic characterization and sequence diversity of the ß2-microglobulin gene in the miiuy croaker, Miichthys miiuy.

ß2-Microglobulin (ß2m) is related to major histocompatibility complex class I alpha chains, and forms cell-surface glycoproteins that mediate a variety of functions in immune defense. In general, ß2m has no isoforms and is not polymorphic in higher vertebrates, but polymorphisms between different alleles have been found in some fish species. In this study, full-length ß2m cDNA and genomic sequences were cloned from the miiuy croaker (Miichthys miiuy). The miiuy croaker ß2m gene shares many of the same characteristics as other fish species. Three exons and two introns were identified in the miiuy croaker ß2m gene; these genomic structural features are similar to those present in other fish. The deduced ß2m amino acid sequence exhibited 34.7-90.1% identity with mammal and teleost ß2m amino acid sequences. Sequence polymorphism analysis in six individuals identified three alleles that encoded two proteins, confirming that ß2m polymorphisms exist in this species. Phylogenetic analysis elucidated the evolutionary history of the ß2m protein among warm-blooded vertebrates and bony fish.

Composition and structure of microbial communities associated with different domestic sewage outfalls.

The diversity of microbiota in waste waters has not been thoroughly examined, despite the potential impact of microbes on effluent quality. Wastewater microbial communities harbor pathogenic bacteria, viruses, and parasites. To study microbial communities in domestic sewage outfalls, 454 pyrosequencing technology was used to investigate the composition of microbial communities associated with municipal wastewater during different seasons sampled over the course of one year. A total of 195,103 16S rRNA gene sequences were obtained from 20 samples. The R software was used to calculate the number of indices describing the alpha diversity associated with each bacterial assemblage. In this study, the a-diversity index (H', D, J), in which higher numbers represent more diversity, was found to change with seasonal cycle. The diversity of bacterial assemblages was high in all samples, indicating that species diversity was also very high. The taxonomic composition of the assemblages varied considerably among samples, with some dominated by Proteobacteria, while others were dominated by Bacteroidetes or Firmicutes. In 2 samples, the relative prevalence of Proteobacteria exceeded 90%. α-Proteobacteria, b-proteobacteria, and g-proteobacteria represented 90% or more of all Proteobacteria. The present characterization of wastewater from five sewage outfalls indicated the presence of some pathogenic bacteria. The g-Proteobacteria in sewage wastefalls identified in this study included Enterobacteriaceae, Vibrionaceae, Pseudomonadaceae, Salmonella, Yersinia, Vibrio, and Pseudomonas aeruginosa.

Identification and assessment of differentially expressed genes involved in growth regulation in Apostichopus japonicus.

Rapid and efficient growth is a major consideration and challenge for global mariculture. The differential growth rate of the sea cucumber, Apostichopus japonicus, has significantly hampered the total production of the industry. In the present study, forward and reverse suppression subtractive hybridization libraries were constructed and sequenced from a fast-growth group and a slow-growth group of the sea cucumber. A total of 142 differentially expressed sequence tags (ESTs) with insertions longer than 150 bp were identified and further analyzed. Fifty-seven of these ESTs (approximately 40%) were functionally annotated for cell structure, energy metabolism, immunity response, and growth factor categories. Six candidate genes, arginine kinase, cytochrome c oxidase subunit I, HSP70, ß-actin, ferritin, and the ADP-ribosylation factor, were further validated by quantitative PCR. Significant differences were found between the fast- and slow-growth groups (P < 0.05) for the expression levels of arginine kinase, cytochrome c oxidase, HSP70, the ADP-ribosylation factor, and ß-actin. However, no significant difference was observed for ferritin. Our results provide promising candidate gene markers for practical size screening, and also further promote marker-assisted selective breeding of this species.

Alteration of Phascolosoma esculenta heat shock protein 90 expression under heavy metal exposure and thermal stress.

The full-length complementary DNA (cDNA) of heat shock protein 90 was cloned from Phascolosoma esculenta (PeHSP90) using expressed sequence tag and rapid amplification of cDNA end approaches. The cDNA of PeHSP90 was 2521 bp including a 5'-untranslated region of 110 bp, a 3'-untranslated region of 230 bp, and an open reading frame of 2181 bp. All of the characteristic motifs of the HSP90 family were completely conserved in the deduced amino acid of PeHSP90. The expression of PeHSP90 was induced by 3 heavy metals or elevated temperature, under which Zn²âº displayed effects were more toxic than those of Cd²âº and Cu²âº. The polyclonal antibodies generated from the recombinant product of PeHSP90 were specifically identified not only in the recombinant product but also in the native protein from hemocytes. These results strongly suggested that PeHSP90 was involved in heavy metal challenge and thermal stress regulation in P. esculenta.

[Content characteristics and cytotoxicity detection of silver ion products].

Objective: To analyze the silver content, homogeneity, and cytotoxicity of silver-containing products. Methods: (1) Five kinds of silver-containing products A, B, C, D, and E were purchased from the market, and products A, B, C, and D are liquid or gel form while product E was dressing form. The silver content of each product and the homogeneity of product E were determined by flame method. The sample number was 3. (2) Human hepatocellular carcinoma cell line (HepG2) was selected as the evaluation model. Four silver-containing products A, B, C, and D were diluted with high-glucose dulbecco's modified eagle medium (DMEM) at multiple ratios of 1∶100, 1∶200, 1∶400, and 1∶800, and then they were used for cell culture. Cells cultured with high-glucose DMEM and high-glucose DMEM containing 20 µg/mL silver nitrate were used as blank control and positive control, respectively. The cell viability was determined by methyl thiazolyl tetrazolium assay, and each sample number was 5. (3) Four mass concentrations of 0.031 3, 0.062 5, 0.125 0, and 0.250 0 µg/mL were prepared from silver-containing product A, and then they were used to culture HepG2 cell. Cells cultured with high-glucose DMEM containing fetal calf serum and 294 µg/mL potassium dichromate were used as positive control, while those containing fetal calf serum were used as blank control. Hoechst 33258 staining method was used to detect apoptosis rate of cells. The tail moment, tail length, and the percentage of DNA in the tail of cells were observed by comet assay to evaluate DNA damage. The sample numbers were all 3. Data were processed with one-way analysis of variance and least significant difference-t test. Results: The silver content of products A, B, C, and D was (256.5±1.5) µg/mL, (271.5±1.3) µg/mL, (652.4±2.6) µg/g , (330.0±2.1) µg/g, which was in accordance with labelled amount. The silver content of product E was (0.158±0.013) mg/g, and the silver content of each piece of product E was (0.125±0.017) mg/g, showing good uniformity of product E. (2) Compared with the rate of blank control, the cell survival rates of product A at the dilution ratio of 1∶100, product B at the dilution ratio of 1∶100, and product C at the dilution ratio of 1∶100 and 1∶200 were significantly reduced (t=35.506, 8.914, 37.594, 30.693, P<0.01). Compared with the rate of positive control, the cell survival rates of product A at the dilution ratio of 1∶200, 1∶400, and 1∶800, product C at the dilution ratio of 1∶400 and 1∶800, products B and D at each dilution ratio were increased significantly (t=27.537, 18.262, 18.709, 26.333, 41.762, 15.776, 19.759, 20.443, 15.715, 26.792, 24.963, 31.803, 30.537, P<0.01). (3) The apoptosis rates of cells treated by 0.250 0 µg/mL product A and positive control were (6.1±0.4)% and (62.2±3.9)% respectively, which were significantly higher than the apoptosis rate of blank control [(3.3±0.7)%, t=13.327, 30.475, P<0.05]. The apoptosis rates of cells treated by 0.031 3, 0.062 5, 0.125 0 µg/mL product A were (2.9±0.4)%, (3.1±0.4)%, and (4.2±0.9)% respectively, which were close to the apoptosis rate of blank control (t=1.181, 0.133, 1.097, P>0.05). (4) The tail moment, tail length, and tail DNA percentage of cells cultured with 0.125 0 and 0.250 0 µg/mL product A were significantly higher than those cultured with blank control (t=29.026, 51.194, 21.851, 36.138, 24.721, 50.455, P<0.05 or P<0.01). However, the tail moment, tail length, and tail DNA percentage of cells cultured with 0.031 3 and 0.062 5 µg/mL product A were close to those cultured with blank control (t=5.878, 3.429, 2.779, 1.960, 1.328, 7.763, P>0.05). Conclusions: The silver content of silver-containing products meets the requirements of the labeling. The concentration of product C is higher than that of other products, leading to a greater possibility of decreasing the survival rate of HepG2 cells. It is suggested that the products A and B should be taken as reference in the concentration setting of silver ion products. The product solution with higher concentration may have higher risk of damage to cell DNA. Therefore, it is not recommended to upregulate silver content of relevant products blindly in order to achieve better antibacterial effect.

[Advances in the research of antibacterial properties of silver ion and its application in wound treatment].

Nowadays, antibacterial products containing silver ion are widely used in clinical wound treatment. The concentration of silver ion in products, pH value, and other factors may affect the release of silver ion and its antibacterial effects. In the treatment of clinical wound, silver ion product plays a good role in anti-infection, promoting healing and reducing medical expenses. In this paper, the related applications of silver ion products in wound surface are analyzed, and the antibacterial properties of silver ion and its therapeutic effects in wound treatment are summarized.

Photochromism and two-photon luminescence of Ag-TiO(2) granular composite films activated by near infrared ps/fs pulses.

We reported photochromism and largely enhanced visible two-photon luminescence (TPL) of Ag-TiO(2) granular composite films by using ps/fs laser at the wavelength of 800 nm. Three types of photochromism spectra were observed when the Ag atom fraction are less than, comparable to and larger than the percolation threshold. The strong surface-plasmon-resonance enhanced visible TPL emissions near Ag(2)O transition band from the photoactivated Ag-TiO(2) samples were also observed. Furthermore, we found that the TPL intensity saturatedly increased while the absorbance at 800 nm exponentially decreased with the same rate as the increasing of photoactivation time, which means that both photochromism and TPL of Ag-TiO(2) composite films are originated from the photo-oxidation of Ag to Ag(+). These observations exhibit the multifunctional features of Ag nanoparticle materials.