Complete Genome Sequence of the Newly Developed Lactobacillus acidophilus Strain With Improved Thermal Adaptability

Abstract

Lactobacillus acidophilus (L. acidophilus) is a representative probiotic and is widely used in many industrial products for its beneficial effects on human and animal health. This bacterium is exposed to harsh environments such as high temperatures for manufacturing industrial products, but cell yield under high temperatures is relatively low. To resolve this issue, we developed a new L. acidophilus strain with improved heat resistance while retaining the existing beneficial properties through the adaptive laboratory evolution (ALE) method. The newly developed strain, L. acidophilus EG008, has improved the existing limit of thermal resistance from 65°C to 75°C. Furthermore, we performed whole-genome sequencing and comparative genome analysis of wild-type and EG008 strains to unravel the molecular mechanism of improved heat resistance. Interestingly, only two single-nucleotide polymorphisms (SNPs) were different compared to the L. acidophilus wild-type. We identified that one of these SNPs is a non-synonymous SNP capable of altering the structure of MurD protein through the 435th amino acid change from serine to threonine. We believe that these results will directly contribute to any industrial field where L. acidophilus is applied. In addition, these results make a step forward in understanding the molecular mechanisms of lactic acid bacteria evolution under extreme conditions.

High-throughput Automated Muropeptide Analysis (HAMA) Reveals Peptidoglycan Composition of Gut Microbial Cell Walls

“…[37][38][39][40][41][42] Based on the muropeptide compositional analysis mentioned above, we found and A. muciniphila have been supported by genome sequence evidence, [43][44][45][46] biochemical evidence is needed to confirm the existence of L,D-transpeptidases in those species.…”

“…37–42 Based on the muropeptide compositional analysis mentioned above, we found high abundances of M3/M3b monomer and D34 dimer in the PGNs of E. faecalis , E. faecium, L. acidophilus, B. breve, B. longum, and A. muciniphila , which may be the PGN products formed by Ldts. While the homologs of Ldts in L. acidophilus, B. breve, B. longum, and A. muciniphila have been supported by genome sequence evidence, 43–46 biochemical evidence is needed to confirm the existence of L,D-transpeptidases in those species.…”

“…However, L,D-transpeptidases are generally insensitive to β-lactams and offer alternative cross-links in the PGNs. 36 Numerous studies have investigated the role of [43][44][45][46] biochemical evidence is needed to confirm the existence of L,D-transpeptidases in those species.…”

Impact of high hydrostatic pressure on the single nucleotide polymorphism of stress-related dnaK, hrcA, and ctsR in the Lactobacillus strains

“…The changes in the environment, such as pressurization, may trigger the activation of adaptive mechanisms and thus maintain changes in the genome, proteome, transcriptome, or metabolome, leading to cell damage and death. Studies (Jeon et al, 2021) on SNPs related to cell wall synthesis in L. acidophilus under high temperatures suggested that changes in SNP can make the cell wall more rigid. Mutations that appear under natural selection increase the possibility of fixation and may often be adaptive.…”

Positive Effect of Lactobacillus acidophilus EG004 on Cognitive Ability of Healthy Mice by Fecal Microbiome Analysis Using Full-Length 16S-23S rRNA Metagenome Sequencing

“…The assembled contig was assessed by BUSCO 3.0.2. The complete sequence of L. acidophilus EG004 that is deposited in the NCBI database with accession number PRJNA657145 was used ( 60 ).…”