Endosymbiotic Theory

Andreas Schimper (1883)

• Plastid division in plants similar to binary fission

Konstantin Mereschkowsi (1905)

• Botanist that proposed symbiogenesis

Dr. Lynn Margulis (1967)

• “On the origin of mitosing cells”

• Symbiosis due to oxygen utilization

• Spirochaete and archaebacterium resulted in eukaryotic flagella and nucleus

Candidatus Midichloria mitochondrii

Bacteria that invade and consume mitochondria of hosts (ticks)

Midi-chlorian

• Microscopic lifeforms in all cells in Star Wars that communicate with the force

• Based on mitochondria

Lokiarchaetoa

• Which shapeshifting bacteria did the engulfing

• Share similarities with eukaryotic membrane-trafficking machinery, coat proteins, and vesicle biogenesis.

Filarial nematodes

• Cause filariasis

  • A form of this is called elephantiasis

• These invertebrate parasitic worms invade human lymph nodes, blocking the lymph ducts which results in edema.

• One nematode, Brugia malayli, harbors bacterium called En spp.

Culture-Dependent Methods (isolate genomics)

• Microbial pure culture > DNA extraction > Genomic DNA (isolated) > DNA sequencing > Raw sequencing reads > Quality control > Clean reads

• you grow an organism, pure culture, so lots of t-streaks, you isolate its DNA, and then you amplify the ribosomal RNA.

Culture-Independent Methods (metagenomics)

• Complex microbial community > DNA extraction > Metagenomic DNA > Metagenomic DNA sequencing > Raw sequencing reads > Data processing > Quality control > Clean reads

• Instead of growing a lot of that bacterium and extracting the DNA, we can sample directly from the environment, amplify as ribosomal RNA sequence and determine who is there.

Whole Genome Sequencing

• DNA extraction > Fragmentation > DNA sequencing > Assembly > Gene finding and annotation > Phylogenetic binning > Metabolic reconstruction

• Determines genome of even uncultivable bacteria from a complex sample

• Can fragment sequence and then assemble partial or whole genomes of a complex sample. So it's using very similar technology except we're not limited to looking at ribosomal RNA. We are limited by the quality and the amount of DNA that we can extract from an environment that can help us to understand who is there, they can also help us to understand what they're doing. And so we can look at the metabolism or the genes that encode for proteins that carry out metabolism to understand how they are living in that environment.