GDB 103 Midterm Flashcards
(77 cards)
What is a disease?
any condition that impairs the normal functioning of the body
What is the Disease Triangle and how do all three components contribute to disease?
host, pathogen, environment. Interaction of susceptible plant host. A virulent plant pathogen. Favorable environment
pyramid or tetrahedron disease triangle
effects of microbes and symbiosis interactions
examples of plant disease and symptoms in plants
fire blight of apple, apple scab, late blight potato
examples of human disease
athlete’s foot, strep throat, measles
mutualism
both species benefit
commensalism
one organism benefits from the other without affecting it
parasitism
one species benefits at the expense of another
binary symbiotic interaction
fungus and cyanobacteria. fungus receives nutrients, cyanobacteria enjoys moist environment and surface attachment
three way symbiotic interaction
late blight of potato. phytopathora infestans and greater than average rainfall, low temps.
Carl Woese and advent of ribosomal SSU sequences
three domain system. universal phylogenetic tree based in SSU rRNA sequences
Aspects of 16S SSU RNA that make it well suited for microbiome analysis
good to place into evolutionary context.
Molecular markers for microbiome analysis in fungi
18S, 5.8S, 28S
importance of PCR
extract DNA, run primers, represent diversity in sample. oligonucleotide primers used to start DNA replication in PCR
Typical work flow
sample collection, extract DNA, SSU rRNA gene amp, DNA sequencing, data analysis
How do we know unculturable organisms exist?
most microbes can’t be cultured in the lab. great plate count anomaly and culture independent approaches
abundance table
quantify and interpret the microbial diversity within samples and/ or between samples
rarefaction curve
plots number of species as a function of the number of sampled organisms
species richness
measure of diversity (unweighted)
Simpson’s index of diversity
number of times each species is observed (weighted)
jaccard dissimilarity
% of species common between 2 sites (unweighted)
bray-curtis dissimilarity
% of individuals within a species that are common between 2 sites (weighted)
UniFrac
“species” similarity. accounts for evolutionary distance
importance of replication
reduce biases, build confidence, more reliable conclusions