11 Microbial Diversity - Bacterial

Question 1

Bacterial taxonomy

Answer 1

Classical (phenotypic)

cell morphology / metabolic activity / staining / pathogenicity / nutritional needs

Question 2

Molecular taxonomy

Answer 2

Genotypic - DNA based (C-G content) / 16S rNA sequencing for prokaryotes (bacteria and archaea) / 18S rNA sequencing for eukaryotes / metagenomics of the whole sample / no reliance on culture

Question 3

Studying microbial diversity (2)

Answer 3

1. Phylogenetic - evolutionary lineages / 16S rRNA sequencing / multi-locus sequence typing (MLST) of housekeeping genes / whole genome sequencing
2. Functional - presence or absence of genes involves in specific pathways or functional mechanisms (Eg. Resistance genes, metabolic pathways, virulence factors)

Question 4

Functional and phylogenic correlation

Answer 4

Function and phylogenic correculate do often correlate but not always —> reasons for this include gene loss / convergent evolution / horizontal gene transfer

Question 5

Functional diversity (3)

Answer 5

Physiological - metabolism and biochemistry

Morphological - appearance

Ecological - organisms relationship with environemnt and what other organisms occupy the same niche

Question 6

Microbial habitats

Answer 6

5° to 120°C —> thermophiles and psychrophiles / salinity - halophiles / pH (acid and alkali) / pressure - barophiles)

Question 7

Diversity of bacteria

Answer 7

Bacterial phyla - largest taxon of prokaryote domain (55 listen in LPSN) / more identified based on 16S rRNA sequencing from heterogenous samples / 90% of those characterised are only from 4 phyla

Question 8

Harsh environments bacteria can live in

Answer 8

hot springs / sulphur pools / thermal ocean vents / underground oil reservoirs

Question 9

Proteobacteria (Pseudomonadata) classes

Answer 9

6 classes

Alpha / beta / gamma / delta / epsilon / zeta

Question 10

Bacteria impact on global nutrient cycle

Answer 10

Recycling of nutrients - breakdown

Without bacteria, nutrients cant be recycled into soil due to slower rates of degradation, so trees and plants have less nutrients to absorb (more competitive), lower rates of plant growth