Gold-Specific Biosensor for Monitoring Wastewater Using Genetically Engineered Cupriavidus metallidurans CH34.

Transcription factor-based whole-cell biosensors have recently become promising alternatives to conventional analytical methods due to their advantage of simplicity, cost-effectiveness, and environmental friendliness. In this study, we used genetic engineering to develop a whole-cell biosensor based on the activation of promoters by CupR via interactions with gold ions, leading to the expression of reporter genes that yield output signals. Altering the promoter sequences was shown to significantly improve the performance of the biosensor strain in terms of gold-specificity. The detection sensitivity of our engineered strains was 42-fold higher than that of wild-type strains. The linear range of the purposed sensor was 125-1000 nM with a limit of detection at 46.5 nM. The effectiveness of the sensor strain was verified in wastewater samples.

Role of stress-activated MAP kinase P38 in cisplatin- and DTT-induced apoptosis of the esophageal carcinoma cell line Eca109.

AIM: To study the role of P38 kinase in esophageal cancer cell apoptosis induced by genotoxin, cisplatin and the unfolded protein response (UPR) inducer, dithiothreitol (DTT). METHODS: Esophageal carcinoma cell line Eca109 was cultured in RPMI 1640 medium to 70% confluency and treated with either cisplatin, DTT, or cisplatin plus DTT in the presence or absence of P38 inhibitor, SB203580. The untreated cells served as the control. The esophageal carcinoma cell apoptosis was detected by agarose gel DNA ladder analysis and quantified by flow cytometry. The P38 phosphorylation was detected by immunohistochemistry using antibodies specific to phosphorylated P38 protein. RESULTS: (1) Both cisplatin and DTT induced apoptosis in the esophageal cancer cell line Eca109 as shown by DNA ladder formation; (2) As detected by antibodies specific for the phosphorylated P38 protein (p-P38), both cisplatin and DTT treatments activated the stress-activated enzyme, MAP kinase P38. The number of positive cells was about 50% for the treatment groups, comparing to that of 10% for untreated group. DTT treatment, but not cisplatin treatment, induces nuclear localization of p-P38; (3) As measured by flow cytometry, inhibition of P38 activity by SB203580 blocks DTT- and cisplatin-induced apoptosis. The rates for DTT, cisplatin, and DTT plus cisplatin-induced apoptosis were 16.8%, 17.1%, and 21.4%, respectively. Addition of the SB compound during the incubation reduced the apoptotic rate to about 7.6% for all the treatment groups, suggesting that P38 activation is essential for cisplatin- and DTT-induced apoptosis in Eca109 cells. CONCLUSION: (1) Both DTT and cisplatin were able to induce apoptosis in esophageal cancer cell line Eca109; (2) P38 MAP kinase is essential for DTT- and cisplatin-induced apoptosis in Eca109 cells; (3) P38 activation may be the common signaling component relaying the multiple upstream signaling events to the downstream cell death program.

[Genetic polymorphisms of six short tandem repeat loci in the Han population of Henan province in China].

OBJECTIVE: To investigate the allele frequencies of six short tandem repeats (STR) loci D12S391, D5S818, D18S51, PAHI3, D8S1179, D3S1358 in the Han population of Henan province and to obtain preliminary data. METHODS: DNA was extracted with phenol-chloroform from 140 EDTA-blood specimens of healthy unrelated individuals in Henan population; multiplex PCR technique and PAGE vertical electrophoresis were used to screen the genotype frequencies of six STR systems in Henan population. RESULTS: The test for Hardy-Weinberg equilibrium revealed that the genotype distribution was correspondent with the expected. The observed heterozygosities of six loci were 0.871, 0.769, 0.871, 0.773, 0.901, 0.722. The calculated discrimination power is 0.9999998, the calculated power of exclusion is 0.99845, the calculated matching probability is 2.39 x 10(-7). CONCLUSION: All of the six loci in this study have high power of discrimination and exclusion; they may be very useful genetic markers for individual identification, paternity test and genetics purposes.