Two pairs of primers specific to small subunit ribosomal DNA of Plasmodium falciparum were designed and the expected SSUrDNA fragment was amplified for detecting P.falciparum infection with double-ternperature-nested polymerase chain reaction using DNA prepared by boiling method. The results showed that the nested PCR could amplify a constant size of desired SSUrDNA fragment of P. falciparum which was further confirmed by digestion of restrlction endonuclease and could detect parasitemia level of 0. 8 ? 10-6. It has great potentials for identifying Plasmodium species in ring form of erythrocytic stage and detecting mixed Plasmodium infections. Therefore, it is suggested that this method is sensitive, accurate, simple and rapid in detecting Plasmodium falciparum in blood samples for malaria diagnosis.

As an efficient and promising protein engineering strategy, directed evolution includes the construction of mutant libraries and screening of desirable mutants. A rapid and high-throughput screening method has played a critical role in the successful application of directed evolution strategy. We reviewed several high-throughput screening tools which have great potential to be applied in directed evolution. The development of powerful high-throughput screening tools will make great contributions to the advancement of protein engineering.
Directed Molecular Evolution ; methods ; High-Throughput Screening Assays ; methods ; Mutagenesis, Site-Directed ; methods ; Mutant Proteins ; genetics ; Protein Engineering ; methods

Objective To investigate the suppression effect, the apoptosis and TGF-β_1 mRNA expression of rhDCN and dororubicin(ADM) on leukemic K562 cell line. Methods K562 cells in Logarithmic growth phase were divided into Saline group, pcDNA3.1 (+)-DCN group, ADM group, and pcDNA3.1 (+)-DCN-ADM group. Morphology change of cell was detected by Wright stain, cell proliferation activity was assessed by MTT. The apoptosis index of K562 cells was assessed by FCM, and TGF-β_1 mRNA of cell was assessed by RT-PCR. Results Wright stain showed that more pronounced morphological apoptosis changes of K562 cells in combined group. MTT method results showed that the proliferation inhibition rate of the combined group was (61±1.32) % higher than that of individual intervention group [DCN group, (20±1.90) %; ADM group, (47±1.04) %](P <0.05). FCM results showed that the apoptosis index of the combined group was (61.30± 0.9) %, higher than that of Individual intervention group [DCN group, (28.25±1.3) %; ADM group, (31.85± 1.5) %](P <0.05). TGF-β_1 mRNA synthesis of combined group was significantly decreased. Conclusion rhDCN can markedly enhance cytotoxicity of ADM on K562 cells, and the mechanisms of apoptosis may be due to down-regulation of TGF-β_1 mRNA. Specific mechanisms will be further studied.

To obtain oleaginous yeast mutants with improved lipid production and growth rates, an atmospheric and room temperature plasma (ARTP) jet was used with a 96-well plate for high throughput screening. Mutants with changes in growth rates and lipid contents were obtained. At a lethality rate of 99%, the positive mutation rate of the yeast cells was 27.2% evaluated by the growth rates of the mutants and the comparison with the wild strain. The fermentation in a medium composed of yeast extract (10 g/L), peptone (10 g/L) and D-glucose (20 g/L) resulted in the lipid yield of the mutant (C4) with 4.07% (W/W) compared with that of the wild strain (1.87%).
Atmosphere ; Biofuels ; Culture Media ; Fermentation ; Glucose ; pharmacology ; Lipids ; biosynthesis ; Mutation ; Peptones ; pharmacology ; Temperature ; Yeasts ; genetics ; growth & development ; metabolism