Interaction involving microorganisms(competitions, amensalism, commensalism, mutualism, parasitism) and fundamental of microbial Ecology

Interaction involving microorganisms and fundamental of microbial Ecology(competitions, amensalism, commensalism, mutualism, parasitism)

1. P r e s e n tation of Environmental Biology Submitted to: Dr. Sagheer Ahmed Submitted by: Amna Azam Javied Roll no. : 857 Semester: 8 th Department: Zoology Topic: Interaction between microorganisms

2. The inter- and intra-relationships between various microorganisms which can include both positive (like SYMBIOSIS) and negative (like ANTIBIOSIS) interactions. Examples include virus - bacteria and bacteria - bacteria. The a s s o ciatio n s a r e v e r y i m p o rtant b i o l o g i c a lly .

3. These includes: Neutralism Mutualism Commensalism Parasitism Cooperation Predation Amensalism Competition Synergism

4. T y p e s o f i n t e r a c t i o ns Positive interaction: Mutualism, Syntrophism, Proto-cooperation, Commensalism Negative interaction: Ammensalism (antagonism), parasitism, predation, competition

5. PARTNERS INVOLVED: MICROBE-MICROBE INTERACTION. MICROBE-PLANT INTERACTION. MICROBE-ANIMAL INTERACTION. MICROBE-HUMAN INTERACTIONS. MICROBE-ENVIRONMENT INTERACTIONS AND DISEASES.

6. NEU T RALISM Microorganisms have no effect on each other. Observed in natural communities if, Culture density is low. Nutrient level is high. Each culture has distinct requirements. E x a m p le : B r e a d m o l d p e n i c i llium

7. Mutualism •An obligatory relationship. • Highly specific. • They operate as a single organism. • Both organisms benefit. • For Eeg.Diatom ( Climacodium ) • and cyanobacteria( Epithemia turgida ) • Lichen-Fungi with Cyanobacteria.

8. Cooperation Positive but not obligatery symbiosis. Can be separated from one another. For eg-Desulfovibrio & Chromatium,Cellulomonas & Azotobactor .

9. Commensalism One partner(commensal) benefits. while other(host) remains unaffected. – Common among organisms, not obligatory – Unidirectional – Usually, unaffected population modifies the environment in a way that other population benefits. For eg -during Nitrification ,oxidation of NH4+ ions get convert into nitrate. Nitrosomonas convert NH4+ Ions to nitrite and nitrobacter oxidise nitrite into nitrate.

10. Parasitism One speices is dependent on a another for nutrition and growth. In it, one organism is benefitted and other is harmed. Closly related to predation. Coexistence between host and parasite. For eg -Viruses are the highly specialized intracellular parasites,generally kill the host.

11. Conti…. Cell. Myxococcus xanthus and E.coli. Microbial parasite may kill the host or can have stable relationship without killing the host.( lysogeny provirus is carried on host chromosome ). Pathogenic parasite may attack and kill the plant or animal host. Obligate parasite Treponema pallidum(syphilis),Rickettsia( Rockey mountain fever) can’t grow without an appropriate host.

12. Predation  It involves predator species which target other microbe for material to survive. attacks and kills its prey. They can be obligate or facultative. Members of predatory bacteria are known as ‘ Bdellovibrio and like organisms’(BALO).They can be epibiotic,periplasmic,cytoplasmic . For eg - Bdellovibrio -E.coli interaction ( Vampirococcus,Daptobacter both attack Chromatium .

13. Amensalism Focuses on exclusion of an organism from growing on a specific site to prevent the utilization of limiting nutrients . Unidirectional process based on the release of a specific compound by one organism that has negative effect on another . Product of one impact another i.e one species remains uneffected while other is harmed. For eg - microbial production of antibiotics that can inhibits or kill another.penicillin by fungi inhibit a type of cell wall found

14. Conti…. only in bacteria. Bacteriocins -kill the strains of closely related species by generating holes in plasma membrane. Metabolic end products.

15. Competition It arises when different organisms within population try to acquire same resources. Both the species are harmed. Competition within the species or among different species can be attributed to availability of Nitrogen source, carbon source, electron donors, electron accepter , vitamins, light, water. Competition may result in exclusion of other species or the establishment of a steady state where multiple species coexist.

16. Conti… Eg - In aquatic environment where extensive phototrophic activity results in blooms of single species of diatoms or cyanobacteria. Thermophilic springs chemolithotrophic organisms are selected. Lactic acid fermentation of food. Large intestine of animals , a single species doesn’t dominate but a mixed population coexist.

17. Syntropism Two species are required for growth on a specific electron donor that is not metabolized by either organism alone or one of the organisms remove end products of metabolism from other , which enables both the organisms to grow. Both the species are benefited. This relationship was discovered by Meyer Wolin and colleagues , when fermentation of propionic acid occurred when there was a coculture . Synophobacter produces H during fermentation and accumulation of H makes the reaction thermodynamically unstable. Pesence of methanogen , Methanospirillum makes the oxidation favourable by consuming the H.’

18. Microbe-Plant Interactions Different interactions between microorganisms and plants have been identified and the most obvious environment for such interactions is soil. Microbe-plant association can be mutulistic (a highly specialized interaction where there is considerable specificity found in mutulistic activities)or it can be commensilistic (secretions from plants benefit bacteria and fungi but no apparent benefit to plant.

19. Bacteria-Root nodule system   Enzyme system for N2 fixation is present only in prokaryotes and nodules are associated with roots of Leguminous plants,bacteria (rhizobia) are specific for a legume species . Assciation is beneficial for both,plant provide c and energy source to bacteria and bacteria fix N2 and provide amino acid to plant. Rhizobium leguminosarum sp.and pea, beans tropical(root nodules ). Azorhizobium caulinodan and Aquatic tropical legume(stem nodule).

20. Microbe-Animal Interaction Bacteria and fungi interact with humans and other animals and this interaction can be symbiotic, commensalistic or parasitic . Symbiotic relationships are widespread and has evolved new metabolic capabilities and cellular structures.( symbiogenesis ). Evolutionary benefits in a symbiotic relationship are;-provision of dietary needs that their hosts lack including essential amino acids , cofactors, metabolic factors etc. N storage and recycling . Large alterations in genome of symbionts and adaptations by host to favour the symbiosis occur during long association which can be in form of genome size reduction or increase in AT content in genome . since endosymbionts protect their hosts from pathogens , this may have influenced the evolution of sociality in animals to acquire the endosymbiont through horizontal and vertical transmission.