Analysis of attached bacteria on algal cells by fluorescence in situ hybridization with oligonucleotide prove

• Project/Area Number: 12640692
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: 系統・分類
• Research Institution: National Institute for Environmental Studies
• Principal Investigator: TOMIOKA Noriko National Institute for Environmental Studies, Waterand Soil Environmental Division, Senior Resercher, 水土壌圏環境研究領域, 主任研究員 (40168399)
• Project Period (FY): 2000 – 2001
• Project Status: Completed (Fiscal Year 2001)
• Budget Amount: ¥2,500,000 (Direct Cost: ¥2,500,000); Fiscal Year 2001: ¥1,200,000 (Direct Cost: ¥1,200,000); Fiscal Year 2000: ¥1,300,000 (Direct Cost: ¥1,300,000)
• Keywords: FISH / DGGE / clone analysis / eutropic lake / hybridization / アオコ

Research Abstract

There are many researches for algal bloom by Cyanobacteria. However, we have not quite understood the mechanism of algal bloom and we can not predict when algal blooms happen, yet. I suppose that attached bacteria on algal cells play an important role on control of algal growth and decomposition of algal cells. However, there are few studies about the relationship between attached bacteria on algal cells and algae. In this study, I focused to elucidate the bacterial species on the algal cells, and their effects to the algal bloom.
First, I studied seasonal and geographical dynamics of bacterioplankton in Lake Kasumigaura by 16S rDNA methods. The results of PCR-denaturing gradient gel electrophoresis (PCR-DGGE) showed that changes in the bacterial community were prominent between different sampling times, but not between different sampling sites. Next, I compared diversity of bacteria in lake water and water removed suspended solids (include algal cells) by pre-filtrate using PCR-DGGE me thods. There is tendency that many bands are in pre-filtrated lake water, on the other hand small number of high density bands are in lake water. This result was regarded that certain bacterial species are predominant on suspended solids. One species bacteria belong to Actinobacteria came frequently predominant in total lake water and pre-filtrated water.
Then I made a primer from 16S rDNA sequence of the Actinobacteria species came predominant to analyze the bacteria attached algal cells. PCR was carried out by using primer set of this primer and 27F universal primer on several bacterial colonies that were selected from Kasumigaura lake water. This primer set found 2 species bacteria and I determined 16S-rDNA sequence of this 2 species. However, unfortunately theses bacterial species belong to Proteobacteria Y Subdivision. Now, I am determining several other primer sequences, once again. And, I determined bacterial fixing condition by paraformaldehyde and fluorescent dye for FISH, in this study.