The Microbial Planet
Bacteria have been on the earth for 3.5 billion years. Molecules aggregate creating proto cells around 5 billion years ago. Complex carbon compounds. Prokaryotic Fossils
Prokaryotic fossils very similar to modern bacteria. Photosynthetic bacteria release oxygen. Oxygen content increased. Oxidising iron in racks - cynobacteria.
Characteristics of cell.
Cell types - Prokaryotic and Eukaryotic.
Endosymbiosis - evolution of Eukaryotics.
1gram of soil contains 100,000 bacterial cells and 11,000 species of bacteria
Charles Darwin - diversity of finches - closely related - beaks used to eat different kinds of food. To assess biodiversity. Distinct, different species, morphological trait comparison - This doesn’t work of microbes.
Bacillus Anthracis. Microbes have no breaks.
Genetic Phylogenic Tree: from looking at genes that erode ribosomes.
Domains of life Archaea, genetically distinct. Archaea more closely related to us.
Bacteria/ Archaea/ Eukayra.
Archaea are usually found in very extreme environments. However, it’s now been found that Archaea are absolutely everywhere . Much more prominent than previously thought.
Obsidian Pool - took water from pool - what organisms are there? found huge diversity and they found completely new forms of life- Archaea and bacterial. Huge diversity in one pool. People have tried to find it in other environments. Hydro Thermal vents.
Prokaryotes comprise 50% of total living Biomass.
Prokaryotes 1.5um in size and have spherical rod or hexical shapes. Cell wall contains peptidoglycens, gram positive, gram negative.
Protobacteria, delta protobacteria and epsilon protobacteria.
Pili - use to adhere to each other or surrounding surfaces. Move around using Folagella. Bio Films. - Fimbriae. Some form colonies and show co-operation or specialisation. Specialised cells fro photosynthesis.
Prokaryotes - don’t have nuclei and internal compartmentalisation. Small simple genomes concentrated in nucleod region. Little associated protein. asexual reproduction - fission.
Plastids - small circular independent pieces of DNA. Major source of genetic variation is mutation.
Transformation / Conjugation / Transduction
Biofilms, capacity to take DNA, cause for variation, transfer of DNA.
E-coli - whole range of variations. MG 1605 - non pathogenic, CFT unpathogenic.
Set of core genes, all other genes are accessory. Core and all accessory = gene reservoir.
Nutritional and Metabolic diversity - obligate aerobes.
Obligate anaerobes - Poisoned by oxygen,
Facultative Anaerobes can use oxygen if available or use fermentation.
Photoautotrophs - Chemoartotrophs - energy from energy of inorganic substances. Photohetrotrophs - light as energy source.
Chemohetrotrophs (Includes human)
Most are Chemhetertrophs and are one of two types 1) saprobes responsible for decomposition of living matter.
Host 1. Mutalism 2. Conversalism 3) paratism.
Bacteria get all plant sugars - example of fish with bacteria.
2) Bacteria adhering to nasal hair.
3) Red band disease - Kills living tissue as it progresses. Anthrax.