[Synergistic Control of Nitrogenous Disinfection By-products and Opportunistic Pathogens in Drinking Water by Iron-Modified Quartz Sand Filtration].

The main function of quartz sand in drinking water treatment has been to remove turbidity, while the microbial effect of its solid-liquid interface has been ignored. In order to solve the limitations of control of the disinfection by-products (DBPs) and opportunistic pathogens (OPs) in common quartz sand, the common quartz sand was modified to iron sand. The maximum DBPs formation potential of typical nitrogenous disinfection by-products (N-DBPs) and carbonaceous disinfection by-products was determined using gas chromatography-ECD. Compared with those of sand, the inhibition effects of halonitromethanes, haloacetamides, and haloacetonitriles by the Fe-sand were increased by 51.51%, 43.66%, and 90.6%, respectively. In addition, the gene copy numbers of Hartmanella vermiformis, Legionella spp., Mycobacterium spp., M. avium, and Naegleria spp. were detected via quantitative qPCR, and the results indicated that the Fe-sand did have a similar significant inhibitory effect on OPs. The Fe-sand had limited ability to enhance the removal of NOM. However, the Fe-sand effectively inhibited the continuous contribution of biofilm to N-DBPs and opportunistic pathogens. The distribution of biofilms on the surface of the Fe-sand filter media was uniform, not likely to fall off, and more stable; however, the suspended biofilms in the effluent were more difficult to aggregate. In addition, the α-helix of the secondary structure in the extracellular protein disappeared in the effluent of the Fe-sand. Therefore, the whole suspended biofilm was easily penetrated by chlorine. The Fe-sand solid-liquid interface did significantly change the microbial community structure and suspended biofilm characteristics, which provides a new concept to ensure the safety of drinking water quality and plays a good theoretical supporting role in the improvement and transformation of the existing process in drinking water treatment plants.

BARX2 expression is downregulated by CpG island hypermethylation and is associated with suppressed cell proliferation and invasion of gastric cancer cells.

BarH­like homeobox 2 (BARX2), a homeobox gene, is associated with several types of cancers. The present study aimed to determine whether DNA methylation downregulates BARX2 expression and whether BARX2 is associated with suppression of gastric carcinogenesis. BARX2 protein expression in normal and cancerous gastric tissues and various gastric cancer (GC) cell lines was detected using immunohistochemical and western blot assays. BARX2 mRNA levels were detected using both reverse transcription­polymerase chain reaction (RT­PCR) and quantitative PCR (qPCR). Promoter hypermethylation in GC cells was detected using methylation­specific PCR or bisulfite DNA sequencing PCR. Effects of BARX2 expression on GC cell proliferation, clonal formation, and migration were evaluated after lentivirus­BARX2 transfection. The effect of stable BARX2 transfection on tumor formation was assessed in a nude xenograft mouse model. BARX2 was strongly expressed in the normal gastric mucosa, but weakly or not expressed in GC tissues and most GC cell lines. BARX2 expression was negatively correlated with DNMT (a marker for DNA methylation) expression in the gastric tissues. The BARX2 promoter fragment was hypermethylated in the GC cell lines. Overexpression of BARX2 significantly inhibited GC cell proliferation, clonal formation, and migration. Stable BARX2 transfection inhibited tumor formation in xenograft mice, which was correlated with decreased expression of E­cadherin, proliferation markers, and matrix metalloproteinases. In conclusion, BARX2 expression is aberrantly reduced in GC, which is associated with increased DNA methylation of its promoter. BARX2 inhibits GC cell proliferation, migration, and tumor formation, suggesting that BARX2 acts as a tumor suppressor in gastric carcinogenesis.

The Wilms tumor gene, Wt1, is critical for mouse spermatogenesis via regulation of sertoli cell polarity and is associated with non-obstructive azoospermia in humans.

Azoospermia is one of the major reproductive disorders which cause male infertility in humans; however, the etiology of this disease is largely unknown. In the present study, six missense mutations of WT1 gene were detected in 529 human patients with non-obstructive azoospermia (NOA), indicating a strong association between WT1 mutation and NOA. The Wilms tumor gene, Wt1, is specifically expressed in Sertoli cells (SCs) which support spermatogenesis. To examine the functions of this gene in spermatogenesis, Wt1 was deleted in adult testis using Wt1(flox) and Cre-ER(TM) mice strains. We found that inactivation of Wt1 resulted in massive germ cell death and only SCs were present in most of the seminiferous tubules which was very similar to NOA in humans. In investigating the potential mechanism for this, histological studies revealed that the blood-testis barrier (BTB) was disrupted in Wt1 deficient testes. In vitro studies demonstrated that Wt1 was essential for cell polarity maintenance in SCs. Further studies found that the expression of cell polarity associated genes (Par6b and E-cadherin) and Wnt signaling genes (Wnt4, Wnt11) were downregulated in Wt1 deficient SCs, and that the expression of Par6b and E-cadherin was regulated by Wnt4. Our findings suggest that Wt1 is important in spermatogenesis by regulating the polarity of SCs via Wnt signaling pathway and that WT1 mutation is one of the genetic causes of NOA in humans.

Effects of different ingredients of zedoary on gene expression of HSC-T6 cells.

AIM: To investigate the effects of four different ingredients of zedoary (Curcuma aromatica oil, Curcumol, beta-elemence, and Curcumin) on the gene expressions of hepatic stellate cells (HSCs), and to explore the molecular mechanism of zedoary against hepatic fibrosis at gene network level. METHODS: We detected the mRNA sequences of 50 liver fibrosis-related genes in GenBank and designed oligonucleotide probes. We synthesized oligonucleotides with PE8909 DNA synthesizing instrument, and carried out oligonucleotide microarray with OGR-04 dropping instrument and aldehyded glass chip. Cultured HSC-T6 cells were treated with different concentrations of Colchicine, Curcuma aromatica oil, Curcumol, beta-elemence, and Curcumin. According to the experiment of cell toxicity, we took the appropriate concentrations of medicines that resulted in over 50% of cell survival as experiment concentrations. We collected the cells at 1, 6, 12, and 24 h, and extracted total RNA with TRIzol reagent, then labeled cDNAs with Cy3-dUTP and Cy5-dUTP. These labeled cDNAs were hybridized to an oligonucleotide microarray which was washed several times and scanned by scanner GenePix 4000B. Different gene expressions of HSC-T6 cells were analyzed by ImaGene 4.2 software. RESULTS: After HSC-T6 cells were cultured in a medium containing 6.25 microg/mL Colchicine for 12 h, expression of TIMP-1 decreased 2.2-folds. After HSC-T6 cells were cultured in a medium containing 78.125 microg/mL of Curcuma aromatica oil for 24 h, the expression of TIMP-2 and IL-6 decreased 2.3- and 2.2-folds, respectively. Moreover, after HSC-T6 cells were cultured in a medium containing 1.5625 microg/mL of Curcumol for 12 h, the expression of TGFbeta1 and P450a decreased 2.3- and 2.1-folds, respectively. CONCLUSION: Our results may show the possible molecular mechanism of Curcuma aromatica oil and Curcumol against hepatic fibrosis.

[Investigations on the molecular mechanisms of saponins from Anemarrhena asphodeloides Bunge using oligonucleotide microarrays].

AIM: To investigate the molecular mechanisms of saponins from the rhizome of Anemarrhena asphodeloides Bunge. METHODS: Oligonucleotide microarrays consisting of 87 probes representing 87 human cardiovascular disease-related genes were constructed. Effects of saponins on gene expression in human umbilical vein endothelial cells were analyzed by comparing hybridization of Cy 5-labeled cDNAs from saponins-treated human umbilical vein endothelial cells and Cy 3-labeled cDNAs from untreated human umbilical vein endothelial cells. RESULTS: The results indicate that angiotensinogen gene, alpha 2A-adrenoceptor gene and endothelin-converting enzyme 1 gene were downregulated 2.8, 1.9 and 3.1 folds respectively after human umbilical vein endothelial cells were incubated in medium containing 80 mg.L-1 saponins. CONCLUSION: These results suggest that saponins may have beneficial effect on cardiovascular diseases by modulating the function of vein endothial cells and microarray can be used to investigate the biological action of extracts from traditional Chinese medicine.