MBIO 3401 - Principles of Microbiology - Symbiosis, Microbiomes

Flashcards covering symbiosis, plant-bacteria/fungi interactions, the human microbiome, and the human virome.

Mutualism

A symbiotic relationship where both organisms benefit.

Commensalism

A symbiotic relationship where one organism benefits and the other is neither harmed nor helped.

Parasitism

A symbiotic relationship where one organism benefits at the expense of the other.

Amensalism

A symbiotic relationship where one organism is harmed and the other is unaffected.

Lichens

A hybrid colony of fungi and algae or cyanobacteria.

Rhizobium

Genus of bacteria capable of nitrogen fixation.

Nitrogen Fixation

Differentiate into non-dividing bacteroids

Mycorrhizae

Network of fungal roots that extend the reach of plant roots, allowing for the plant access to additional soil resources.

Ectomycorrhizae

The fungi colonize the surface of roots.

Endomycorrhizae

The fungi penetrate the root cells (arbuscules).

Aliivibrio fischeri

Capable of producing bioluminescence

lux genes

Genes for bioluminescence controlled by quorum sensing.

The Rumen

Large fermentation chamber colonized by microbes capable of anaerobic fermentation that the host cannot digest.

Cellulolytic Microbes

Produce enzymes that hydrolyze cellulose to glucose

Human Microbiome

Living on and within the human body are approximately 10^13 microbes

Variation in Microbiome

Different sites of the body are inhabited by different communities of bacteria depending on their microenvironment.

Example of Microbiome Variation

The skin is dry; the intestines are more moist.

Oral microbiome

Dry environment that sustains a unique community of bacteria.

Dental Plaque

To avoid being removed from the mouth by swallowing, bacteria adhere and form biofilms.

Stomach

pH of 2 that inhibits growth of most microbes.

Helicobacter pylori

Unique for its high acid tolerance and growth in mucosal lining.

Large Intestine

High microbial load.

Large Intestine Bacteria

Predominated by anaerobic bacteria, some facultative.

Microbes in the large intestine (gut microbiome)

Play a significant role in breaking down complex carbohydrates and modulating the immune system

Human Virome

The human virome includes bacteriophages and eukaryotic viruses

Bacteriophages

Play a crucial role in modulating the microbiome by influencing the population of bacteria.

Role of Bacteriophages in Disease

Facilitating horizontal gene transfer, potentially spreading genes for antibiotic resistance or virulence.