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Author: search.filters.author.Phongsopitanun, WongsakornSubject: search.filters.subject.lactic acid bacteria

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    Lentilactobacillus terminaliae sp. nov., isolated from tree bark (Terminalia ivorensis Chev.) and its antioxidant activity
    (2025-01-01)
    Phuengjayaem, Sukanya
    ;
    Kingkaew, Engkarat
    ;
    Chamroensaksri, Nitcha
    ;
    Phongsopitanun, Wongsakorn
    ;
    Tanasupawat, Somboon
    A Gram-stain-positive, facultatively anaerobic, rod-shaped strain, designated SPB1-3<sup>T</sup>, was isolated from tree bark. This strain exhibited heterofermentative production of dl-lactic acid from glucose. Optimal growth was observed at 25–40 °C, pH 4.0–7.0, and in the presence of 3% (w/v) NaCl. The cell wall peptidoglycan contained lysine and aspartic acid. The predominant fatty acids identified were C<inf>16:0</inf> and the Summed feature 7 (C<inf>19:1</inf> ω7c/C<inf>19:1</inf> ω6c and/or C<inf>19:1</inf> ω6c/ω7c/19cy). The polar lipid profile included phosphatidylglycerol, diphosphatidylglycerol and phosphatidylinositol, along with two unidentified phospholipids, two unidentified amino lipids and two unidentified lipids. Phylogenetic analysis based on 16S rRNA gene sequences positioned strain SPB1-3<sup>T</sup> within the genus Lentilactobacillus, showing a close relation to Lentilactobacillus kosonis NBRC 111893<sup>T</sup> (99.86%) and Lentilactobacillus curieae CCTCC M 2011381<sup>T</sup> (98.65%). The whole genome of strain SPB1-3<sup>T</sup> comprised 1 932 998 base pairs with 1955 coding genes and a DNA G+C content of 37.8%. Digital DNA–DNA hybridization between strain SPB1-3<sup>T</sup> and closely related type strains ranged from 19.50 to 27.20%. The average nucleotide identity ranged from 84.21 to 85.56%, and the average amino acid identity ranged from 57.25 to 85.99%, both falling below the established thresholds for species delineation. Strain SPB1-3<sup>T</sup> was clearly distinguishable from related Lentilactobacillus species based on its phenotypic and chemotaxonomic char-acteristics, 16S rRNA gene sequence similarity and whole genome analysis. Additionally, the strain exhibited radical scavenging activity at 66.92% and demonstrated 82.32% inhibition in the tyrosinase inhibitory assay. These findings support the classification of strain SPB1-3<sup>T</sup> as a novel species within the genus Lentilactobacillus, for which the name Lentilactobacillus terminaliae sp. nov. is proposed. The type strain is SPB1-3<sup>T</sup> (=JCM 35081<sup>T</sup>=TISTR 10005<sup>T</sup>).
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    Lactiplantibacillus argentoratensis and Candida tropicalis Isolated from the Gastrointestinal Tract of Fish Exhibited Inhibitory Effects against Pathogenic Bacteria of Nile Tilapia
    (2023-02-01)
    Siangpro, Noppadon
    ;
    Chuakrut, Songkran
    ;
    Sirimanapong, Wanna
    ;
    Tanasupawat, Somboon
    ;
    Phongsopitanun, Wongsakorn
    Nile tilapia is one of the most consumed farmed fish in the world. The outbreak of pathogenic bacterial diseases causes high mortality rates and economic losses in Nile tilapia farming. Antibiotic administrations are commonly utilized to inhibit and prevent bacterial infections. However, antibiotics are expensive and cause serious concerns for antibiotic resistance in fish that can be potentially transferred to humans. As an alternative solution, probiotics can be used to prevent infection of pathogenic bacteria in fish. In this work, both bacteria and yeast were isolated from fish gastrointestinal tracts and their inhibitory activity against Nile tilapia pathogenic bacteria was evaluated, as well as other probiotic properties. In this study, 66 bacteria and 176 acid tolerant yeasts were isolated from fish gastrointestinal tracts. Of all isolated microorganisms, 39 bacterial and 15 yeast isolates with inhibitory effect against pathogens were then examined for their probiotic properties (acidic and bile salt resistance, adhesion potential, and biofilm formation), formation of antibacterial factor survival rate under simulated gastrointestinal fluid, and safety evaluation. AT8/5 bacterial isolate demonstrated probiotic properties and the highest inhibition against all 54 tested pathogens while YON3/2 yeast isolate outperformed the inhibitory effect among all yeast isolates. These two probiotic isolates were further identified by 16S rDNA and the D1/D2 domain of 26S rDNA sequence analysis for bacterial and yeast identification, respectively. AT8/5 and YON3/2 showed the highest similarity to Lactiplantibacillus argentoratensis and Candida tropicalis, respectively. This is the first report on isolated L. argentoratensis and C. tropicalis with antipathogenic bacteria of Nile tilapia properties. Collectively, AT8/5 and YON3/2 could be potentially used as promising alternatives to existing antibiotic methods to prevent pathogenic bacteria infection in Nile tilapia farming.