Bacterial Investigation By Terminal Restricton Fragment Length Polymorphism

The bacteria] communities in seawater and shrimp pond during culturation were described by 16S rRNA gene (rDNA)-based Terminal Restricton Fragment Length Polymorphism (T-RFLP)analysis. And 13 strains of bacteria were compared by T-RFLP.Community DNA in seawater was extracted, and the extraction ratio was 5. 84ng/mL. Then 16S rDNA fragments were amplified by PCR with the reverse primer f luorescently labeled, and the PCR products were digested by Mspl. The fluoescently labeled terminal restriction fragments were analyzed by electrophoresis on an automatic sequence analyzer. The results show that there were more than 10 peaks in the figure representing even more species of bacteria. Between 19-25 minutes' electrophoresis bacteria corresponding to peaks of E, F, I and J comprise more than 80% of this bacterial community, indicating that they were predominant groups. And the area of the peak I was the largest of all the peaks.From July to September, 2002, the bacterial communities in shrimp pond were analyzed by T-RFLP technique. Bacteria in some samples were also counted by plate spread method. Three T-RFs' (Terminal Restricton Fragments) peaks comprised the largest area in the T-RFLP profile. This bacterial cmmunity was mainly composed of these three groups of bacteria, each of which became the largest group at different periods. The abundances of the bacteria corresponding to peaks of I, II, III and IV were calculated according to plate count results and the peaks' areas. The abundance of the three groups of bacteria changed during culturation.13 strains of bacteria were compared after individual T-RFLP analysis. They were divided into 6 groups according to their T-RFs, and 4 groups contain one different strain respectively. Then the other 2 groups were analysed by Msel-based T-RFLP. Each group can be divided again. Eventually the 13 strains were divided into 9 groups.