Probiotic Properties of Lactic Acid Bacteria with High Conjugated Linoleic Acid Converting Activity Isolated from Jeot-Gal, High-Salt Fermented Seafood

Conjugated linoleic acid (CLA) isomers are potent health-promoting fatty acids. This study evaluated the probiotic properties of 10 strains of high CLA-producing lactic acid bacteria (LAB) isolated from Jeot-gal, a high-salt, fermented seafood. Two isolates, Lactiplantibacillus plantarum JBCC105683 and Lactiplantibacillus pentosus JBCC105676, produced the largest amounts of CLA (748.8 and 726.9 μg/mL, respectively). Five isolates, L. plantarum JBCC105675, L. pentosus JBCC105676, L. pentosus JBCC105674, L. plantarum JBCC105683, and Lactiplantibacillus paraplantarum JBCC105655 synthesized more cis-9, trans-11-CLA than trans-10, cis-12-CLA (approximately 80:20 ratio). All the strains survived severe artificial acidic environments and showed antimicrobial activity and strong adhesion capability to Caco-2 cells as compared to the commercial strain Lactocaseibacillus rhamnosus GG. Among them, Pediococcus acidilactici JBCC105117, L. paraplantarum JBCC105655, and L. plantarum JBCC105683 strongly stimulated the immunological regulatory gene PMK-1 and the host defense antimicrobial peptide gene clec-60 in Caenorhabditis elegans. Moreover, three strains showed a significant induction of tumor necrosis factor-α, interleukin (IL)-1β, IL-6, IL-12, and IL-10 production in RAW 264.7 macrophages, indicating that they were promising candidates for probiotics with high CLA-converting activity. Our results indicate that the newly isolated CLA-producing LAB might be useful as a functional probiotic with beneficial health effects that modulate the immune system.

Genomic analysis of halophilic bacterium, Lentibacillus sp. CBA3610, derived from human feces

BACKGROUND

Lentibacillus species are gram variable aerobic bacteria that live primarily in halophilic environments. Previous reports have shown that bacteria belonging to this species are primarily isolated from salty environments or food. We isolated a bacterial strain CBA3610, identified as a novel species of the genus Lentibacillus, from a human fecal sample. In this report, the whole genome sequence of Lentibacillus sp. CBA3610 is presented, and genomic analyses are performed.

RESULTS

Complete genome sequence of strain CBA3610 was obtained through PacBio RSII and Illumina HiSeq platforms. The size of genome is 4,035,571 bp and genes estimated to be 4714 coding DNA sequences and 64 tRNA and 17 rRNA were identified. The phylogenetic analysis confirmed that it belongs to the genus Lentibacillus. In addition, there were genes related to antibiotic resistance and virulence, and genes predicted as CRISPR and prophage were also identified. Genes related to osmotic stress were found according to the characteristics of halophilic bacterium. Genomic differences from other Lentibacillus species were also confirmed through comparative genomic analysis.

CONCLUSIONS

Strain CBA3610 is predicted to be a novel candidate species of Lentibacillus through phylogenetic analysis and comparative genomic analysis with other species in the same genus. This strain has antibiotic resistance gene and pathogenic genes. In future, the information derived from the results of several genomic analyses of this strain is thought to be helpful in identifying the relationship between halophilic bacteria and human gut microbiota.

Lentibacillus saliphilus. sp. nov., a moderately halophilic bacterium isolated from a saltern in Korea

A novel moderately halophilic bacterial strain, designated YIM 93176^T, was isolated from a saltern in Korea and subjected to a polyphasic taxonomic study. This isolate YIM 93176^T was observed to grow in the presence of 0-22% (w/v) NaCl and at pH 6.0-10.0 and 10-45 °C; optimum growth was observed with 5-10% (w/v) NaCl and at pH 7.0-9.0 and 28-37 °C. Based on 16S rRNA gene sequences analysis, the nearest relatives were Lentibacillus alimentarius M2024^T (96.5% similarity), followed by Virgibacillus carmonensis LMG 20964^T (96.0%) and the other type strains of the family Bacillaceae, but phylogenetic analysis indicated that strain YIM 93176^T belonged to the cluster comprising type species of the genus Lentibacillus. Genome sequencing of strain YIM 93176^T revealed a genome size of 3.2 Mb and a DNA G + C content of 40.5 mol%. The major fatty acids were anteiso-C_15:0 (40.7%) and iso-C_15:0 (26.4%), while the predominant respiratory quinone was menaquinone 7. The polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. These genotypic and chemotaxonomic characteristics supported affiliation of strain YIM 93176^T to the genus Lentibacillus. In addition, phenotypic characteristics could distinguish strain YIM 93176^T from its closely related species in genus Lentibacillus. Based on the cumulative evidences from the polyphasic taxonomic study, strain YIM 93176^T represents a novel species of the genus Lentibacillus, for which name Lentibacillus saliphilus sp. nov. (type strain YIM 93176^T = CCTCC AB 208139^T = DSM 21375^T) is proposed.

Lentibacillus cibarius sp. nov., isolated from kimchi, a Korean fermented food

Two bacterial strains designated NKC220-2^T and NKC851-2 were isolated from commercial kimchi from different areas in Korea. The strains were Gram-positive, aerobic, oxidaseand catalase-positive, rod-shaped, spore-forming, non-motile, and halophilic bacteria. Both strains grew without NaCl, unlike type species in the genus Lentibacillus. The optimal pH for growth was 8.0, higher than that of the type species in the genus Lentibacillus, although growth was observed at pH 5.5-9.0. 16S rRNA gene sequence-based phylogenetic analysis indicated that the two strains (99.3-99.9% similarity) are grouped within the genus Lentibacillus and most closely related to Lentibacillus juripiscarius IS40-3^T (97.4-97.6% similarity) isolated from fish sauce in Thailand. OrthoANI value between two novel strains and Lentibacillus lipolyticus SSKP1-9^T (79.5-79.6% similarity) was far lower than the species demarcation threshold. Comparative genomic analysis displayed differences between the two strains as well as among other strains belonging to Lentibacillus. Furthermore, each isolate had strain-specific groups of orthologous genes based on pangenome analysis. Genomic G + C contents of strains NKC-220-2^T and NKC851-2 were 41.9 and 42.2 mol%, respectively. The strains contained meso-diaminopimelic acid in their cell walls, and the major menaquinone was menaquinone-7. Phosphatidylglycerol, diphosphatidylglycerol, and an unidentified glycolipid, aminophospholipid, and phospholipid were the major polar lipid components of both strains. The major cellular fatty acids of the strains were anteiso-C_15:0 and anteiso-C_17:0. Based on phenotypic, genomic, phylogenetic, and chemotaxonomic features, strains NKC220-2^T and NKC851-2 represent novel species of the genus Lentibacillus, for which the name Lentibacillus cibarius sp. nov. is proposed. The type strain is NKC220-2^T (= KACC 21232^T = JCM 33390^T).

Lentibacillus lipolyticus sp. nov., a moderately halophilic bacterium isolated from shrimp paste (Ka-pi)

A Gram-stain-positive, aerobic, spore-forming, moderately halophilic bacterium, SSKP1-9^T, was isolated from traditional salted shrimp paste (Ka-pi) produced in Samut Sakhon Province, Thailand. This strain grew optimally at 37-40 °C, pH 7.0 and in the presence of 8-16 % (w/v) NaCl. The 16S rRNA gene sequence similarity values between strain SSKP1-9^T and Lentibacillus juripiscarius TISTR 1535^T and Lentibacillus halophilus TISTR 1549^T were 98.7 and 97.2 %, respectively. Based on 16S rRNA gene sequence similarity, strain SSKP1-9^T represents a distinct novel species, as shown by phenotypic traits, DNA-DNA hybridization and average nucleotide identity values. In addition, the whole-cell protein profile confirmed the novelty of the taxon. The genomic DNA G+C content was 44.6 mol%. The major isoprenoid quinone was MK-7. The cell-wall peptidoglycan contained meso-diaminopimelic acid. Polar lipid analysis revealed the presence of phosphatidylglycerol, diphosphatidylglycerol, four unidentified lipids, an unidentified phospholipid and an unidentified glycolipid. The major cellular fatty acids were anteiso-C_15 : 0, anteiso-C_17 : 0 and iso-C_16 : 0. The results of phenotypic and chemotaxonomic characteristics and whole-genome analysis support that strain SSKP1-9^T represents a novel species of Lentibacillus, for which the name Lentibacilluslipolyticus sp. nov. is proposed. The type strain is SSKP1-9^T (=JCM 32625^T=TISTR 2597^T).

Evolution in the Bacillaceae

The family Bacillaceae constitutes a phenotypically diverse and globally ubiquitous assemblage of bacteria. Investigation into how evolution has shaped, and continues to shape, this family has relied on several widely ranging approaches from classical taxonomy, ecological field studies, and evolution in soil microcosms to genomic-scale phylogenetics, laboratory, and directed evolution experiments. One unifying characteristic of the Bacillaceae , the endospore, poses unique challenges to answering questions regarding both the calculation of evolutionary rates and claims of extreme longevity in ancient environmental samples.

Pseudogracilibacillus auburnensis gen. nov., sp. nov., isolated from the rhizosphere of Zea mays

A Gram-positive-staining, aerobic, endospore-forming bacterium, strain P-207T, was isolated from a rhizosphere soil sample in Auburn, AL, USA. On the basis of 16S rRNA gene sequence comparisons, strain P-207T was grouped in the vicinity of representatives of the genera Virgibacillus , Ornithinibacillus , Cerasibacillus , Lentibacillus and Oceanobacillus , but could not be assigned clearly to any of these genera. The highest similarity was found to the sequence of Virgibacillus carmonensis LMG 20964T (94.4 %); however, the 16S rRNA gene sequence similarity to the type strain of the type species of Virgibacillus , Virgibacillus pantothenticus , was only 92.9 %. The quinone system of strain P-207T consisted predominantly of menaquinone MK-7. The polar lipid profile exhibited the major lipids diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine and moderate to minor amounts of several unidentified phospholipids, glycolipids and phosphoglycolipids, an aminophospholipid and an aminolipid. The diagnostic diamino acid of the peptidoglycan was meso-diaminopimelic acid and the polyamine pattern contained predominantly spermidine and spermine. The major fatty acids were anteiso-C15 : 0, anteiso-C17 : 0, iso-C16 : 0 and iso-C15 : 0. The G+C content of the genomic DNA was 34 mol%. Because of the low sequence similarity of strain P-207T to all representatives of Virgibacillus , Ornithinibacillus , Cerasibacillus , Lentibacillus and Oceanobacillus , which was always <95 %, and its unique lipid pattern, we propose that strain P-207T represents a novel species in a new genus, for which the name Pseudogracilibacillus auburnensis gen. nov., sp. nov. is proposed. The type strain of Pseudogracilibacillus auburnensis is P-207T ( = CCM 8509T = LMG 28212T = CIP 110797T).

Genome sequence of Lentibacillus jeotgali Grbi(T), isolated from traditional Korean salt-fermented seafood

Lentibacillus jeotgali Grbi(T), isolated from a traditional Korean salt-fermented seafood, is a strictly aerobic, Gram-positive, nonmotile, endospore-forming, moderately halophilic bacterium belonging to the family Bacillaceae in the phylum Firmicutes. Here, the draft genome sequence of L. jeotgali Grbi(T) (3,775,822 bp with a G+C content of 42.5%) is reported. This is the first reported genome sequence from a Lentibacillus species.