Construction of DNA ladder based on 16S rRNA gene of Bacillus subtilis using touchdown PCR technique

Aim@#DNA molecular size markers or DNA ladders play a vital role in molecular biology laboratories where DNA electrophoresis experiments are usually conducted. This study aimed to produce a 100 bp DNA ladder at laboratory scale, which could be applied to determine the size of DNA fragments in molecular biology experiments.@*Methodology and results@#In this study, 14 primers including 4 forwards and 10 reverses were designed based on the 16S rRNA gene sequence of Bacillus subtilis. These primers were able to amplify 10 DNA fragments with accurate sizes from 100 to 1000 bp. Furthermore, touchdown PCR was involved to maximize the specificity and yield of PCR products. Ten DNA fragments with the sizes including 100, 200, 300, 400, 500, 600, 700, 800, 900 and 1000 bp were synthesized, and such bands were equivalent with commercial DNA ladders. Moreover, the quantity and quality of PCR products were measured using a nanodrop spectrophotometer. The optimal concentration ratios between such fragments (100- 1000 bp) were 800, 300, 150, 150, 500, 50, 50, 50, 50 and 50 (ng/µL), respectively. These ratios showed the clear and high resolution on 1.5% agarose gel. @*Conclusion, significance and impact of the study@#The results indicated that 16S rRNA gene of B. subtilis was a potential material for DNA ladder preparation due to the multiple copies number of this gene. Furthermore, in combination with touchdown PCR, the nonspecific bands were reduced, and the products could be used directly without the need of purification step.

Investigation on working conditions and health of employees in some handicraft villages

Cross-sectional study was conducted in 6 handicraft villages, 600 producing households, 1.672 handicraft employees and 135 agricultural employees. The study results showed that: 98.4% of producing households had generated hazardous factors such as noise, heat, dust, micro-organism etc. In food processing village: 83.3% of micro-climate samples and 100% of light samples exceeded the permissible limits. In mechanical villages: 100% of noise sample accessed the permissible limit. In fine arts furniture villages: 91.3% of micro-climate sample, 75% of light sample and 69.5% of dust sample exceeded the permissible limits. In general, almost of handicraft employee had poor knowledge on risk factors at workplaces and their harms. The disease prevalence of handicraft employees was 85.3% that was higher than that of agricultural employee (58,5%). The difference was statistic significant (p=0.0001; RR= 1.46). Handicraft employee liked to have healthcare services at commune’s health station or have health workers at worker place and health insurance.

Effects of isoniazid and pyrazinamide on bioavailability of rifampicin when co-administered rifampicin-isoniazid

The study was conducted to compare bioavailability of rifampicin at the same doses with and without isoniazid and pyrazinamide in the standard separate tablets in 12 healthy volunteers. Bioavailability of rifampicin was estimated by plasma concentration of rifampicin from 0h to 24h after administration. Plasma rifampicin concentration was determined by HPLC method. The results revealed that Cmax and AUC for rifampicin was reduced (31.24% and 25.95%, respectively) when rifampicin - isoniazid - pyrazinamide was administeredat the same time. It was concluded that bioavailability of rifampicin was affected by presence of isoniazid and pyrazinamide.