Microbiology Quiz 4 (Lectures 27-33)

nitrifiers

convert ammonia to nitrate

denitrifiers

convert nitrate into nitrite & n2 gas

eutrophication

nutrient enrichment induced water pollution (caused by N and P in runoff from fertilizers)

systematics

study of diversity of microorganisms and their relationships

phylogeny

evolutionary history of organisms

homology

genes inherited from a shared ancestor

orthologous

homologous genes with a shared function

paralogous

homologous genes with different functions (from gene duplication)

node

where ancestor diverged into 2 new lineages

homoplasy (convergent evolution)

organisms share a trait not derived from common ancestry

monophyletic

all share recent common ancestor

genomically coherent

high degree of genetic similarity

phenotypically coherent

similar observable traits, can be differentiated from other species

Multilocus sequence analysis (MLSA)

differentiates organisms on species level, not used to differentiate closely related species

average nucleotide identity (ANI)

estimates overall genome relatedness between 2 organisms

evolution

a change in gene or allele frequency in a population over time

genetic drift

random process that can cause gene frequencies to change over time without selection (most impactful in small populations → bottleneck)

loss of function

loss of characteristic trait that is no longer beneficial to organisms fitness

gain of function

gain of new trait is beneficial to organisms fitness

gene duplication

redundant copy of a gene; can accumulate random mutations with loss of gene function

RuBisCO gene

gave rise to paralogous enzymes with different but related catalytic activities

mobilome

all mobile genetic elements in genome; have genes encoding their own replication, recombination, and transmission

chromosomal islands (gene islands)

clusters of genes for specialized functions

pathogenicity islands

molecules that facilitate disease and found primarily in pathogenic bacteria

symbiosome

microcolony of bacteriods surrounded by portions of the plant cytoplasmic membrane

fiber

structural component of plant cell walls; insoluble polysaccharides such as cellulose

foregut fermentation

microbial fermentation occurs before the small intestines (broken down before reaching stomach and small intestine)

hindgut fermentation

microbial fermentation occurs between small and large intestines (cecum contains fiber and cellulose digesting microorganisms)

rumen

foregut digestive organ, has microorganisms for digesting cellulose and other polysaccharides

microbial fermentation in the rumen

glucose → bacterial fermentation → volatile fatty acids & gases → released by belching

butyrate (SCFA)

immune surveillance, controls metabolism, tight junction proteins maintained = no leaky gut