title: The role of beneficial bacteria wall elasticity in regulating innate immune response.
abstract: BACKGROUND
  Probiotics have great potential to contribute to development of healthy dietary regimes, preventive care, and an integrated approach to immunity-related disease management. The bacterial wall is a dynamic entity, depending on many components and playing an essential role in modulating immune response. The impact of cell wall elasticity on the beneficial effects of probiotic strains has not been sufficiently studied. The aim was to investigate the effect of lactic acid bacteria (LAB) and bifidobacteria strains on phagocytic system cells (macrophages) as related to bacterial wall elasticity, estimated using atomic force microscopy (AFM).
  
  
  METHODS
  We conducted studies on Balb/c line mice 18-20 g in weight using lyophilized strains of LAB-Lactobacillus acidophilus IMV B-7279, Lactobacillus casei IMV B-7280, Lactobacillus delbrueckii subsp. bulgaricus IMV B-7281, and bifidobacteria-Bifidobacterium animalis VKL and Bifidobacterium animalis VKB. We cultivated the macrophages obtained from the peritoneal cavity of mice individually with the strains of LAB and bifidobacteria and evaluated their effect on macrophages, oxygen-dependent bactericidal activity, nitric oxide production, and immunoregulatory cytokines. We used AFM scanning to estimate bacterial cell wall elasticity.
  
  
  RESULTS
  All strains had a stimulating effect on the functional activity of macrophages and ability to produce NO/NO2 in vitro. Lactobacilli strains increased the production of IL-12 and IFN-γ in vitro. The AFM demonstrated different cell wall elasticity levels in various strains of LAB and bifidobacteria. The rigidity of the cell walls among lactobacilli was distributed as follows: Lactobacillus acidophilus IMV B-7279 > Lactobacillus casei IMV B-7280 > Lactobacillus delbrueckii subsp. bulgaricus IMV B-7281; among the strains of bifidobacteria: B. animalis VKB > B. animalis VKL. Probiotic strain survival in the macrophages depended on the bacterial cell wall elasticity and on the time of their joint cultivation.
  
  
  CONCLUSIONS
  LAB and bifidobacteria strains stimulate immune-modulatory cytokines and active oxygen and nitrogen oxide compound production in macrophages. Strains with a more elastic cell wall according to AFM data demonstrated higher resistance to intracellular digestion in macrophages and higher level of their activation. AFM might be considered as a fast and accurate method to assess parameters of probiotic strain cell wall to predict their immune-modulatory properties.
authors.affiliation: Zabolotny Institute of Microbiology and Virology, National Academy of Sciences of Ukraine, 154, Zabolotny st., Kyiv, D03680 Ukraine.
authors.forename: Viktoria V
authors.initials: VV
authors.lastname: Мokrozub
authors.affiliation: Zabolotny Institute of Microbiology and Virology, National Academy of Sciences of Ukraine, 154, Zabolotny st., Kyiv, D03680 Ukraine.
authors.forename: Liudmyla M
authors.initials: LM
authors.lastname: Lazarenko
authors.affiliation: Pure Research Products, LLC, 6107, Chelsea Manor Court, Boulder, CO 80301 USA.
authors.forename: Liubov M
authors.initials: LM
authors.lastname: Sichel
authors.affiliation: Zabolotny Institute of Microbiology and Virology, National Academy of Sciences of Ukraine, 154, Zabolotny st., Kyiv, D03680 Ukraine.
authors.forename: Lidia P
authors.initials: LP
authors.lastname: Babenko
authors.affiliation: Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine, 41, pr. Nauky, Kyiv, 03028 Ukraine.
authors.forename: Petro M
authors.initials: PM
authors.lastname: Lytvyn
authors.affiliation: LCL «Diaprof», Svitlycky Str., 35, Kyiv, 04123 Ukraine.
authors.forename: Olga M
authors.initials: OM
authors.lastname: Demchenko
authors.affiliation: Zabolotny Institute of Microbiology and Virology, National Academy of Sciences of Ukraine, 154, Zabolotny st., Kyiv, D03680 Ukraine.
authors.forename: Yulia O
authors.initials: YO
authors.lastname: Melnichenko
authors.affiliation: Zabolotny Institute of Microbiology and Virology, National Academy of Sciences of Ukraine, 154, Zabolotny st., Kyiv, D03680 Ukraine.
authors.forename: Nadiya V
authors.initials: NV
authors.lastname: Boyko
authors.affiliation: Dipartimento di Scienze Agrarie, Alma Mater Studiorum-Bologna University, Bologna, 40127 Italy.
authors.forename: Bruno
authors.initials: B
authors.lastname: Biavati
authors.affiliation: Dipartimento di Scienze Agrarie, Alma Mater Studiorum-Bologna University, Bologna, 40127 Italy.
authors.forename: Diana
authors.initials: D
authors.lastname: DiGioia
authors.affiliation: Zabolotny Institute of Microbiology and Virology, National Academy of Sciences of Ukraine, 154, Zabolotny st., Kyiv, D03680 Ukraine ; Clinical Hospital "Pheophania" of State Affairs Department, Zabolotny str., 21, Kyiv, 03680 Ukraine.
authors.forename: Rostyslav V
authors.initials: RV
authors.lastname: Bubnov
authors.affiliation: Zabolotny Institute of Microbiology and Virology, National Academy of Sciences of Ukraine, 154, Zabolotny st., Kyiv, D03680 Ukraine ; LCL «Diaprof», Svitlycky Str., 35, Kyiv, 04123 Ukraine.
authors.forename: Mykola Ya
authors.initials: MY
authors.lastname: Spivak
keywords: Atomic force microscopy; Bifidobacterium; Cancer; Cell wall elasticity; Cytokines; Dietary biomarkers; Fecal microbiota transplantation; Gut microbiota; Gut–brain axis; Healthy diet; Immune disorders; Lactobacillus; Macrophages; Microbiome; Nutrition; Oxidative; Pattern-recognition receptors; Predictive; and personalized medicine; nitrosative stress; preventive