Microbes

1. Crenarchaeota

2. Euryarchaetota

3. Hyperthermophiles

4. Sulfolobales

• Sulfolobus acidocaldarius
• Grows in sulfur-rich hot springs
• Aerobic chemolithotrophs that oxidise reduced sulfur to iron
• Live at 90'C, pH1-5, spherical, adheres to sulfur crystals
• S-layer of proteins, anchored to the membrane

5. Desulfurococcales 

• Found in nutrient poor marine environments
• Can survive in very cold seawater and ice
• Planktonic
• Identified by SSU rRNA sampling
• Can fix inorganic carbon
• Plays key role in carbon cycle

• Halobacterium salinarum
  • Extreme halophile
  • have a requirement for high salt concentrations, at least 1.5M, NaCL needed for growth
  • Found in sea salt evaporation ponds
• Adaptations to high salt
  • High solute levels in cells lead to high osmotic pressure, maintain a positive water balance by pumping K+ into cells
  • Higher K+ inside than Na+ outside
  • Glycoprotein cell wall stabilised by Na+
  • Cellular protiens composed of more acidic amino acids so they are more soluble at higher solute concentrations

• Produce Methane
  • severalcarbon substrates can be used
  • ATP produced
• Unique to Archaea
  • Important in degradation of organic matter
• Found in
  • Sediments with low O2
  • Animal digestive tracts
  • Hydrothermal vents
• Obligate anaerobes
• Pseudomurin in cell wall

• causes anthrax
• >80% mortality is untreated
• Growth in lymph nodes and lymphatic tissue of lungs
• death from septisemia, haemorrhagic and menigitis
• Endospore structure:
  • Many layers
  • Contains dipicolinic acid with Ca2+ which dehydrates endospore and stabalises DNA
  • Core contains small acid-soluble proteins that bind to DNA and protect from damage are used as a carbon and energy source for germination
• Toxic parasporal chrystal
  • BT toxin toxic to inset larvae
  • help make insect resistant crops

• Nonsporulating 
• aerobic
• produces cocci
• resistant to reduced water potential
• tolerate high salt
• many species are pigmented
• E.g. Staphylococcus aureus is yellow

• Lacks a cell wall
• key components of peptodoglycan abscent
• membranes contain sterols and lipoglycans which stabalise the membrane
• Pleomorphic
  • cells may be cocci or filamentous of various lengths
• capable of autonomous growth
• inhabit animal and plant hosts
• often defective in several biosynthetic pathways 
• E.g Mycoplasma genitalium
  • host associated
  • genome 580bp
  • 470 genes

Actinobacteria

• Rod-shaped
• Obigate aerobe
• Faculative intracellular parasite with complex cell wall,
• E.g Mycobacterium tuberculosis

• Branching filaments
• produces spores called conida
• Important secondary metabolites
  • produce antibiotics and extracellular enzymes
• strict aerobes
• genomes large
• soil dwelling
• role in carbon cycling: produce hydrolytic exoenzymes
• spores form when colony ages

• Pseudomonas aeruginosa
  • infects urinary and respiratory tract
  • infects burn wounds
  • resistant to antibiotics
• Capable of breaking down many components including oil so can be used in bioremediation, however, may turn pathogenic
• Can infect plants, causes hypersensitivity in TMV

• Includes E. coli
  • Inhabit intestinal tract
  • may synthesize vitamins for host
  • can be pathogenic
  • salmonella and shigles closely related, usually pathogenic
• Faculative aerobes
  • Ferments sugars produces a mixture of acids, H2 and CO2
• May be motile
• Nonsporulating
• Simple nutrient requirements

• Cells are motile, straight or curved rods
• Faculative aerobes/ fermentative metabolism
• inhabit aquatic environments
• E.g. Vibrio cholerae
• Some can cause biolumenescence
  • catalysed by luciferase
  • regulated by population density via quorem sensing
  • Associated with fish- host provides nutrients and shelter, luminescence can be used for communication and hide host from predators
  • Requires luciferae, long chain aliphaitc aldehyde, flavin and oxygen
  • Lux operon

• Prey on other bacteria
• small genome
• highly motile
• obligate aerobes
• widespread in soil and water
• Cycle:
  • attachment and penetration of host
    • resides in periplasm
    • breaks down peptiglycan
    • assimilates organic compounds from prey cytoplasm
  • elongates without dividing
  • cell division occurs once nutrients are depleted
    • filament divides
    • differentiation into motile forms

• Motile
• Microaerophilic
  • requires small conc of O2
• Campylobacter causes bloddy diahorrea
• Helicobacter causes gastritis and peptic ulcers

• Long rods or filaments
• Lack flagella, can move when is contact with surfaces
• Myxospores
  • nutrients depleted
  • vegetative cells aggregate
  • construct fruiting bodies
  • differentite into myxospores
  • resistant to drying, UV and heat

• Oxygenic phototrophs
• most are obligate phototrophs
• important in producing oygen in the early atmosphere
• gave rise to chloroplasts via endosymbiosis
• Morphologically diverse
  • unicellular and filamentous 
• many produce potent neurotoxins
• Found in terrestrial, freshwater and marine habitats
• peptidoglycan in cell walls
• outer and cytoplasmic membranes present
• Mucilagenous envelopes
• Gas vesicles help maintain buoyancy
• many display gliding motility

• Symbiosis between fungi and phototrophic organism
  • algae or cyanobacteria
  • cyanobacteria can fix nitrogen
  • fungus gains organic matter from photosynthesis
  • bacteria gains anchorage, water and inorganic nutrients

• Motile
• Tightly coiled
• Treponema- flate wave form
  • host associated- parasites of humans
  • cause syphalis 
  • some are parasites of the mouth
  • some found in rumen
• others are helical
• widespread in aquatic environments and animals
• Cell structure
  • protoplasmic cylinder enclosed by cell wall and membrane
  • outer shealth- flexibke and made of lipid, protein and carbohydrate
  • Endoflagella: located under periplasm
• Motility
  • Endoflagella anchored at one end
  • Move via flexing or lashing

• Gram negative type cell wall
• Does not stain
• Outer lipopolysaccaride membrane
• lacks peptidoglycan
• obligate parasites
  • poor metabolic capasities
  • require biosynthetic intermediates
  • simple biochemical capasities
• Chlamydia trachomatis 
  • small genome
  • missing genes supplied by host
  • genes for peptidoglycan and ATP present
  • some genes acquired by horizontal gene transfer
• Infections
  • STD
  • Non-specific urethrisis 
  • Trachoma (blindness)
  • Associated with reactive arthritis