2018, 37(06):40-44.
Abstract:Flow cytometry and spectrophotometry were used to measure the cell numbers and absorbances of three common cultures including Escherichia coli S17-1, Synechocystis sp. PCC 6803 and Bacillius subtilis 168 at different concentrations in the laboratory. Then the absorbance values and cell numbers of each culture were compared. The function relationship between absorbance and cell numbers was established. The results showed that the absorbance value and cell numbers of the three common cultures in the laboratory were significantly positively correlated with the concentration at the certain concentration. It was verified that the absorbance value of the culture can reflect the number of cells during the culture process using the fitting function. The relationship between the absorbance and cell number of three strains including Escherichia coli S17-1, Synechocystis sp. PCC 6803 and Bacillius subtilis 168 was established. It will provide the foundation for developing biological experiments to determine the cell number and downstream molecules in the culture using a spectrophotometer.
2018, 37(3):87-91.
Abstract:In this paper,the genome size (C-value) and ploidy of 5 commercial fishes including Onychostoma sima,triploid Cyprinus carpio var. singuonensis,Myxocyprinus asiaticus,Sinibotia superciliarisa and Hemibarbus maculatus were determined by flow cytometry using chicken erythrocyte DNA content as a standard. The results showed that the C-values of O. sima,triploid C. carpio var. singuonensis,M. asiaticus,S. superciliarisa and H. maculatus were 1.18±0.01 pg,1.92±0.07 pg,2.62±0.28 pg,0.89±0.01 pg and 1.24±0.02 pg,respectively. The C-value of M. asiaticus was the largest,followed by triploid C. carpio var. singuonensis, H. maculatus,O. sima and S. superciliarisa. Among the 5 economic fishes,there is no difference in C-values between O. sima and H. maculatus (the same family) (P＞0.05),but the difference between the other species (different families) was significant (P<0.05). Ploidy analysis showed that O. sima,S. superciliarisa and H.maculatus were diploid,C. carpio var. singuonensis was triploid and M. asiaticus was tetraploid.
2016, 35(2):56-62.
Abstract:One plasmid DNA with egfp and Kanr was introduced into the natural soil.The positive transformants were isolated directly from the bacterial suspension with flow cytometer and sorted with green fluorescence and kanamycin resistance.The frequency of natural transformation was less than 10-7 in soil.After the enrich cultivation,82 cells out of 39 736 426 were sorted.Positive transformants were finally obtained.The occurrence of horizontal gene transfer through natural transformation in soil was confirmed.Our studies break the lowest proportion limit of sorting with flow cytometry as well.
2012, 31(3):371-375.DOI: 1000-2421（2012）03-0371-05
Abstract:The chromosome number and karyotype of Pseudorasbora parva were analyzed using a routine method including intraperitoneal injection of PHA and colchicine,cultivation in vivo,and slides preparation with air-drying.Whilst erythrocyte nuclear DNA content of P.parva was determined by using a flow cytometer (Beckman Coulter Inc.,USA) with serving the chicken erythrocytes (their DNA content is 2.30 pg) as reference cells.Results obtained in this study showed that:the diploid chromosome number of P.parva was 50 (2n=50); the karyotype of this species was 2n=18 m+22 sm+10 st,NF=90,while the secondary constriction,heterosome and satellite chromosome were not observed; the diploid cellular DNA contents of P.parva was 3.18 pg,which was 1.38 times to the chicken erythrocytes’.