Module 15- Environmental Factors Flashcards
Used to show probiotics are effective against illness to a number of diseases
Meta-analysis
Variables to Consider for factors that influence probiotic functions
- Strain Choice and dose
- Duration and frequency of administration
- Knowledge on Probiotic cell constituents and host (microbial Interactions)
Factors that influence probiotic functions
Environmental and host factors
Environmental Factors that Affect Probiotic Function (6)
Diet, host ethnicity and genetics, Geographical location, Strain growth and preservation, delivery matrix, gut microbiota, host age and health
Molecular Determinants of Probiotic Effects
Effectors
Probiotic cell effector molecules (8)
Secreted proteins, polyphosphate, PG, LTA, Metabolites, EPS, DNA, Pili, antimicrobials, cell surface proteins
Effectors production and activity
Modified by environmental factors
Effectors that strengthen intestinal barrier
Secreted proteins (p40/p75) and polyphosphate
Effectors that are involved in immunomodulation (7)
PG, tiechoic acids, secreted proteins and peptides, histamine (metabolite), EPS, DNA, pili
Effectors that. protect against pathogens
Antimicrobials such as bacteriocins and reuterin + Cell surface proteins + EPS + acetate (metabolite)
Strain production and preservation environmental stimuli that can alter bacterial composition
Culture conditions (pH and aeration) + Growth phages of processing
Culture conditions influence…
Bacterial survival in products and digestive tract + effector molecules for host-probiotic interactions
Culture conditions influencing effectors example
Growth of Bifidobacterium bifidim in human milk oligosaccharides –> IL-10 expression
Growth phase of processing effects
Effector molecules
Growth phase effects example
Aggregation promoting factors in L. acidophilus
Product Delivery Matrix
Few studies to compared different food matrices and formulations
Most common food matrix
Dairy but others like fruit juice can be used
Product formulation direct effect on probiotics
Physiochemical barriers to gastric acid, nutrients that is selectively metabolized in product or gut, cell sufrace specific expression
Cell surface expression by
Dairy products as delivery matrix
Cell-surface expression example
L. casei shorter upon incubation with milk vs conventional media
Growth media can effect
Cell morphology
Ability to respond to dietary conditions might regulate…
Probiotic protection against human pathogens
Bifidobacterium with enhances capacities to ferment sugars to acetate….
End product protected germ free mice of E. coli O157:H7
Host Physiology
Genetics, ethnicity, age, health status influence probiotics health effect and effects of indigenous microbiota
Regular consumption of yogurt by healthy people…
Did NOT significantly change fecal microbiota
Probiotics on intestinal microbiota
Metabolic pathway specifically toward polysaccharide metabolism
Probiotic performance linked to
Individual dietary components
Lactose in drinking water…
S. thermophilus LMD9 colonization in rats
Lactate Production by S. thermophius
Induction of transporters and cell cycle arrest protein in epithelial cells
Histamine from AA histidine
Induce epithelial cell responses toward inhibiting TNF (pro-inflammatory)
Histamine produced by
L. reuteri
