| Title | Cultivable butyrate-producing bacteria of elderly Japanese diagnosed with Alzheimer’s disease |
|---|---|
| Author | Thi Thuy Tien Nguyen1,2, Yuta Fujimura1, Iyo Mimura3, Yusuke Fujii1, Ngoc Luong Nguyen4, Kensuke Arakawa1, and Hidetoshi Morita1* |
| Address | 1Graduate School of Environmental and Life Science, Okayama University, Okayama 700-8530, Japan, 2College of Agriculture and Forestry, Hue University, Hue 531940, Vietnam, 3Graduate School of Interdisciplinary Information Studies, The University of Tokyo, Tokyo 113-0033, Japan, 4College of Science, Hue University, Hue 530000, Vietnam |
| Bibliography | Journal of Microbiology, 56(10),760–771, 2018, |
| DOI | 10.1007/s12275-018-8297-7 |
| Key Words | 16S rRNA gene sequencing, Alzheimer’s disease, butyrate-producing bacteria, gut microbiota, short-chain fatty acids |
| Abstract | The group of butyrate-producing bacteria within the human gut microbiome may be associated with positive effects on memory improvement, according to previous studies on dementia- associated diseases. Here, fecal samples of four elderly Japanese diagnosed with Alzheimer’s disease (AD) were used to isolate butyrate-producing bacteria. 226 isolates were randomly picked, their 16S rRNA genes were sequenced, and assigned into sixty OTUs (operational taxonomic units) based on BLASTn results. Four isolates with less than 97% homology to known sequences were considered as unique OTUs of potentially butyrate-producing bacteria. In addition, 12 potential butyrate-producing isolates were selected from the remaining 56 OTUs based on scan-searching against the PubMed and the ScienceDirect databases. Those belonged to the phylum Bacteroidetes and to the clostridial clusters I, IV, XI, XV, XIVa within the phylum Firmicutes. 15 out of the 16 isolates were indeed able to produce butyrate in culture as determined by high-performance liquid chromatography with UV detection. Furthermore, encoding genes for butyrate formation in these bacteria were identified by sequencing of degenerately primed PCR products and included the genes for butyrate kinase (buk), butyryl-CoA: acetate CoAtransferase (but), CoA-transferase-related, and propionate CoA-transferase. The results showed that eight isolates possessed buk, while five isolates possessed but. The CoA-transfer- related gene was identified as butyryl-CoA:4-hydroxybutyrate CoA transferase (4-hbt) in four strains. No strains contained the propionate CoA-transferase gene. The biochemical and butyrate-producing pathways analyses of butyrate producers presented in this study may help to characterize the butyrate-producing bacterial community in the gut of AD patients. |