BIOL1262- Diversity of OrganismsMetabolic and nutritional diversity of microorganisms

Bacterial growth

Carbon and energy metabolismAll microbes need sources of energy and carbon

Source of energyChemical compounds (Chemotrophs)Some microbes OXIDIZE organic compounds and some OXIDIZE inorganic compounds

Light (Phototrophs)Carry out oxygenic or anoxygenic photosynthesis

Source of carbonInorganic sources (Autotrophs)Mainly carbon dioxide

Organic carbon (Heterotrophs)Use preformed organic carbon

Carbon and energy metabolismOrganisms that use organic compounds for energy and carbon (Chemoheterotrophs)Utilize processes including glycolysis, TCA (Krebs) cycle, cytochrome chain.

Organisms can be: - Aerobic Anaerobic Facultative Microaerophilic (5-10%) Aerotolerant (

Carbon and energy metabolismOrganisms that use inorganic compounds for energy and carbon (chemoautotrophic)

Calvin cycle is used for fixing carbon (just like plants)

These are aerobesMechanism of ATP synthesis by organism using NH3 as energy source

Carbon and energy metabolismMicrobes that carryout photosynthesisSulfur and non-sulfur photosynthetic bacteriaVery diverse groupOne photosystem normally usedBacteriochlorophyl-basedMainly anaerobicAnoxygenic (sulfur and hydrogen compounds and some organic compounds serve as electron donors) Cyanobacteria and algaeJust like plantsChlorophyl-basedAerobicOxygenic (water is electron donor

Photosynthesis in cyanobacteria and algae

Photosynthesis in green sulfur bacteria

Microbial nutritionModes of nutritionChemoautotrophic microbes (lithotrophs) are referred to as rock eatingE.g. NH3 and NO2 oxidizing bacteria (nitrifying bacteria) and sulfur oxidizing bacteria

Microbial nutritionModes of nutritionChemoheterotrophs The saphrophytesUtlize dead or decaying organic matter for growth requirementsThese are the major decomposers of organic matter on earthMain degradative agents even for organisms killed by pathogens

Microbial nutritionModes of nutrition- Chemoheterotrophic interactions Parasities -Endo or exoparasites

Mutualistic associations (obligatory relationship)

Symbiosis/ProtocooperationNon-obligatory beneficial associations

Commensals

Amensalism- product of one organism affects another organism

Predation

Competition

Microbial nutritionModes of nutritionENDOPARASITESEXOPARASITES

Microbial nutritionModes of nutrition: Symbiosis

Both partners benefit from partnership when it would be beneficial from both

Symbiosis would not occur or not occur properly if one partner already has optimal growth conditions

Microbial nutritionModes of nutrition: MutualismOne or both partners cannot carryout important functions without the other

Microbial nutritionModes of nutrition: CommensalismThese benefit from host which does not benefit nor is harmed by the association

Microbial nutritionModes of nutrition: Amensalism

Evolution of eukaryotic nutritionhttp://www.growingpassion.org/2010/04/evolution-of-chloroplasts-endosymbiosis.html