Acid resistance and response to pH-induced stress in two Lactobacillus plantarum strains with probiotic potential.
Two new Lactobacillus plantarum strains, KR6-DSM 28780 and M5 isolated from sour turnip and traditional dried fresh cheese, respectively, were evaluated for species identity, antibiotic susceptibility, resistance to gastrointestinal conditions and adaptive response to low pH. Resistance mechanisms involved in the adaptation to acid-induced stress in these two strains were investigated by quantitative PCR of the atpA, cfa1, mleS and hisD genes. In addition to absence of antibiotic resistance, the two L. plantarum strains showed excellent survival rates at pH values as low as 2.4. Adaptive response to low pH was clearly observed in both strains; strain KR6 was superior to M5, as demonstrated by its ability to survive during 3 h incubation at pH 2.0 upon adaptation to moderately acidic conditions. In contrast, acid adaptation did not significantly affect the survival rate during simulated passage through the gastrointestinal tract. In both strains, induction of histidine biosynthesis (hisD) was upregulated during the acid adaptation response. In addition, significant upregulation of the cfa1 gene, involved in modulation of membrane fatty acid composition, was observed during the adaptation phase in strain KR6 but not in strain M5. Cells adapted to moderately acidic conditions also showed a significantly increased viability after the lyophilisation procedure, a cross-protection phenomenon providing additional advantage in probiotic application.
Acies Bio, d.o.o., Tehnološki park 21, 1000 Ljubljana, Slovenia Medis, d.o.o., Brnčičeva 1, 1231 Ljubljana-Črnuče, Slovenia.
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Šeme
Acies Bio, d.o.o., Tehnološki park 21, 1000 Ljubljana, Slovenia.
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Gjuračić
Department of Biochemical Engineering, Faculty of Food Technology and Biotechnology, University of Zagreb, Pierottijeva 6, 10000 Zagreb, Croatia.
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Kos
Acies Bio, d.o.o., Tehnološki park 21, 1000 Ljubljana, Slovenia.
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Fujs
Medis, d.o.o., Brnčičeva 1, 1231 Ljubljana-Črnuče, Slovenia.
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Štempelj
Acies Bio, d.o.o., Tehnološki park 21, 1000 Ljubljana, Slovenia Biotechnical Faculty, Department of Food Science and Technology, University of Ljubljana, Jamnikarjeva 101, 1000 Ljubljana, Slovenia.
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Petković
Department of Biochemical Engineering, Faculty of Food Technology and Biotechnology, University of Zagreb, Pierottijeva 6, 10000 Zagreb, Croatia.
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Šušković
Biotechnical Faculty, Institute of Dairy Science and Probiotics, University of Ljubljana, Groblje 3, 1230 Domžale, Slovenia.
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Bogovič Matijašić
Acies Bio, d.o.o., Tehnološki park 21, 1000 Ljubljana, Slovenia.
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Kosec
D000143:Acids / Q000494:pharmacology*; D000222:Adaptation, Physiological / Q000187:drug effects; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D029688:Brassica napus / Q000382:microbiology; D002611:Cheese / Q000382:microbiology; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D006863:Hydrogen-Ion Concentration; D048191:Lactiplantibacillus plantarum / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*; D019936:Probiotics / Q000737:chemistry; D013312:Stress, Physiological / Q000187:drug effects
D000143:Acids; D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins
acid stress; cross resistance; lyophilisation; qPCR