Host as Community Flashcards
What is symbiosis?
A long-term intimate relationship between two organisms
3 types of relationships?
Parasitism (-ve for host +ve for symbiont)
Commensalism (neutral to host +ve for symbiont)
Mutualism (+ve for host and symbiont)
what are 4 ways in which the host can view the symbiont?
Pathogen that can kill
Neutral
Beneficial
Essential
What are the mutual benefits?
Symbiont
- Food
- Shelter
- Neighbours with whom to share/compete
Host
- Metabolic functions and digestion
- Nutrients
- Pathogen exclusion/antagonism
- Developmental regulation
Example of symbiont benefiting the host through developmental regulation
Developmental regulation of intestinal angiogenesis by indigenous microbiota
How do normal microbiota at birth differ from those in adulthood?
At birth - facultative anaerobes
Adulthood - Obligate anaerobes
Two ways in which a good relationship can go bad
Right bug, wrong place
= bacteremia
= scepticemia
= aspriation pneumonia
- Disturbed microbial community
= Microbiome disease (dont involve an exogenous pathogen)
= Opportunistic infections
What is dysbiosis or dysbacteriosis?
Something wrong with the community that is causing something negative
What is the relationship between normal microbiota and innate immune system?
Intimate
What can disturbances in the relationship between microbiota and innate immune system lead to?
Local and or systemic effects
What are two possible examples of disturbed microbial community?
Inflammatory bowel disease (IBD) in dogs
Necrotic enteritis in poultry
What is necrotic eneritis in poultry?
Acute or chronic enterotoxemia in chickens
What is thought to be the possible cause of Necrotic enteritis
Clostridium perfringens
- gram +ve spore forming anaerobe
- Produces a variety of toxins
- Occurs at low levels naturally in intestines
What is the cause for the hazardous affect of C. perfringens?
Elimeria spp causes damage to intestinal epithelium which causes for protein to leak into intestine. The increase availability of protein causes for Dysbiosis and proliferation of resident C. perfringens which causes necrotic enteritis
What are 3 ways in which we try to restore balance?
Antibiotics - can cause even more of a problem by killing other normal microbiota
Probiotics - Live microbes administered in adequate amount confering a health benefit on the host, science is very weak and not regulated industry
Prebiotics - An ingredient that results in specific (beneficial) changes in the composition and or activity of the GI microbiota