Lactococcus intestinalis sp. nov., a new lactic acid bacterium isolated from intestinal contents in Alzheimer’s disease mice

• Published in: Antonie van Leeuwenhoek 2023-05, Vol.116 (5), p.425-433
• Main Authors: Sun, Peilin, Li, Xue, Shi, Weixiong, Zhang, Ling, Li, Ming, Su, Lei, Qin, Chuan
• Format: Article
• Language: English
• Subjects: Alzheimer Disease; Alzheimer's disease; Animals; Bacteria; Bacterial Typing Techniques; Biomedical and Life Sciences; Cardiolipin; Deoxyribonucleic acid; DNA; DNA, Bacterial - genetics; DNA-directed RNA polymerase; Fatty Acids; Gastrointestinal Contents; Gene sequencing; Genes; Genomes; Glyceraldehyde-3-phosphate dehydrogenase; Hybridization; Intestine; Lactic Acid; Lactococcus; Life Sciences; Lipids; Medical Microbiology; Mice; Microbiology; Neurodegenerative diseases; New species; Nucleic Acid Hybridization; Nucleotide sequence; Nucleotides; Original Paper; Phosphatidylethanolamine; Phosphatidylglycerol; Phospholipids; Phylogeny; Plant Sciences; RNA, Ribosomal, 16S - genetics; RpoB protein; rRNA 16S; Sequence Analysis, DNA; Soil Science & Conservation
• ISSN: 0003-6072; 1572-9699
• DOI: 10.1007/s10482-023-01814-3

A gram-positive, facultatively anaerobic, and coccoid or ovoid-shaped bacterium designated M2458 T was isolated from the intestinal contents of APP swe /PS ΔE9 mouse model of Alzheimer’s disease. With the polyphasic approach, the taxonomic position of the novel isolate was confirmed. Strain M2458 T grew well at 37 °C on YCFA agar. Strain M2458 T belongs to the family Streptococcaceae and class Bacilli, and it is closed to Lactococcus formosensis NBRC 109475 T (97.59% sequence similarity) according to its 16S rRNA gene sequence. In a comparison of two housekeeping genes, rpoA and rpoB , strain M2458 T was found to be well separated from Lactococcus formosensis NBRC 109475 T . On the basis of whole genome sequences, the DNA G+C content was 38.29 mol%. The phylogentic analysis of the whole genome showed that a different branch was clearly formed in the phylogenetic tree of strain M2458 T compared to other strains in the genus Lactococcus . A total of eight genes in strain M2458 T are involved in the ‘neurodegenerative disease’ pathway, which involves an annotated protein (glyceraldehyde 3-phosphate dehydrogenase) involved in Alzheimer's disease. In terms of average nucleotide identity and digital DNA–DNA hybridization, strain M2458 T was identified as a novel species of the genus Lacococcus . The major fatty acids (> 10% of the total fatty acids) were C18:1ω9c (39.68%), C16:0 (13.26%) and C18:1ω7c (11.52%). The polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, and an unidentified phospholipid. As a result of its genotypic and phenotypic characteristics, strain M2458 T was considered to be a new species within the genus Lactococcus ; the name Lactococcus intestinalis sp. nov. has been proposed, with type strain M2458 T (=JCM 35706 = CGMCC 1.60066).