Microbial Interactions K R. pptx

Microbial Interactions K R.pptx

1. Microbial Interactions K R MICRO NOTES 1

2. Microbial Interactions Organisms does not exist alone in nature But it is a matrix of other organism of many species.. Interaction is the rule of nature When one or more types of organisms reciprocate each others effect is called interaction. Interaction may be between two population in following manner - both population unaffected, or - one or both population benefit or - one or both population adversely affected Interaction are broadly classified into two types based on their effect on each other 1. Positive Interaction 2. Negative Interaction. K R MICRO NOTES 2

3. Positive interaction Exist between tow populations enhance the ability of the Interacting populations to survive within the community of particular Habit without affecting the population . Generally positive interaction dominate at low population densities. Relationship may be unilateral – unaffected population modifies the habitat and other population benefit . Relationship may be non-obligatory between two populations which satisfy each others needs. Interaction may be highly specific and obligatory , population cannot be replaced other population. Positive interaction classified into following types. 1. Commensalism 2. Synergism 3. Mutualism. K R MICRO NOTES 3

4. Commensalism it is positive interaction Interaction occurs between two populations. One population benefits and other one is unaffected . It is unidirectional relationship between two populations. The unaffected population modifies the habitat and another population benefits . Modified habitat more suitable for the growth of another population. The interaction is nonobligatory one population can replace with another population. Commensalism is exhibited in a number of ways. 1. Commensalism plays important role- need for the production of growth factors. Example: Flavobacterium brevis (Cysteine) taken by Legionella pneumophila K R MICRO NOTES 4

5. Commensalism 2. Transformation of Insoluble compounds to soluble and further into gaseous compounds. Insoluble Soluble Gaseous Example: Methane from sediments benefits methane oxidizing population in overlaying water. 3. Conversion of complex organic molecules to simple molecules by one population and simple molecule as substrate for the other population. Example: Fungi breakdown the complex lignin by extracellular enzymes and release simple glucose molecule which benefits fro the other population. Lignin (extracellular enzymes ) simple glucose K R MICRO NOTES 5

6. Commensalism 4. Two organisms tend to remain together to satisfy their metabolic needs. Example: Mycobacterium vaccae growing on propane as a source of carbon and energy, will grow gratuitously oxidize cyclohexane to Cyclohexanone which are readily used up by other microorganism Pseudomonas . Pseudomonas benefits because they are unable to metabolize Cyclohexane. . Where as Mycobacterium remains unaffected and it does not assimilate Cyclohexanone. K R MICRO NOTES 6

7. Commensalism 5. Removal or neutralization of toxic material by one population and modify the environment and other population benefited. Example: Detoxification H 2 S through oxidation of by Beggiattoa detoxifies it, and befit to growth of H 2 S sensitive aerobic organisms. Some organisms detoxify through Immobilization- Leptothrix reduces High manganese toxi concentration and permitting the growth of other microbes (low manganese toxic concentration) K R MICRO NOTES 7

8. Synergism or Proto-cooperation it is positive interaction Interaction occurs between two populations. both population benefits form the interaction . It is Bidirectional relationship between two populations. The interaction is not obligatory one population can replace with another population. Both population are capable of surviving independently, and both populations are gain the advantage from this interaction. These interactions are loose in that one member can be readily replaced by another member. Two population supply each others nutritional needs (Cross feeding) Synergism or Proto-Coperation is exhibited in a number of ways. K R MICRO NOTES 8

9. Synergism or Proto-cooperation 1. Arginine is converted to Putresciene by E.coli and Enterococcus fecalis both working together. When the organism are alone cannot convert Arginine is converted to Putresciene . Arginine ( Enterococcus fecalis ) Ornithine Ornithine ( E.coli ) Putresciene Bothe the microorganism nutritional needs are fulfilled. 2. Interaction allow Supply of growth factor by one population for another ( Nocardia and Pseudomonas together degrade the Cyclohexane) Nocardia act on supply metabolic products to Cyclohexane Pseudomons release Biotin The pseudomonas supply Biotin to Nocardia . K R MICRO NOTES 9

10. Synergism or Proto-cooperation 3. The interaction occurred by mutual exchange of required growth factors between two populations. Lactobacillus arabinosus required Phenylalanine for their growth & Streptococcus fecalis required Folic acid for their growth. Both the population cultivated on Minimal media can grow by mutual acquiring of growth factors, when alone growth cannot exist or occurred. Lactobacillus arabinosus Streptococcus fecalis (Folic acid) (Phenylalanine) 4. The relationship between Chlorobium (Green algae) and Desulfovibrio (Chemolithotrophic bacterium). Chlorobium fix CO 2 through Photosynthesis and use H 2 S as the electron donor and oxidize to Sulphur. The Desulfovibrio require elemental sulphur which reduces to H 2 S and organic compounds for their growth supplied by the algae. K R MICRO NOTES 10

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15. Mutualism it is positive interaction and Extension of synergism Interaction occurs between two populations both population benefits form the interaction . It is Bidirectional relationship between two populations. The interaction is highly specific and obligatory one population cannot replace with another population. Both population are capable of surviving together and both populations are gain the advantage from this interaction. These interactions are strong in that one member cannot be replaced by another member. Two population supply each others nutritional needs (mutually feeding) Mutalism is exhibited in a number of ways. K R MICRO NOTES 15

16. Mutualism Lichens: are excellent example of mutualism. They are the association of specific fungi and certain genus of algae. In lichen, fungal partner is called  mycobiont  and algal partner is called Phycobiont is member of cycanobacteria ad green algae ( Trabauxua ). Because phycobionts are photoautotrophs, the fungus get its organic carbon directly from algal partner, in turn fungi protects the phycobiont from extreme conditions and also provide water and minerals to algae. Lichen grow very slowly but are able to colonies habitat that do not permit the growth of other organisms. Most lichens are resistant to high temperature and drying. K R MICRO NOTES 16

17. Mutualism ii. Protozoan-termite: Protozoan-termite relationship is the classical example of mutualism in which flagellated protozoan lives in the gut of termites. Theses flagellated protozoan feeds on diet of carbohydrates acquired as cellulose or lignin by their host termites, metabolize into acetic acid which is utilized by termites. K R MICRO NOTES 17

18. Mutualism iii. Paramecium-Chlorella: Paramecium  (protozoa) can host  Chlorella  (algae) within its cytoplasm. The algae  Chlorella  provide the protozoan partner with organism carbon and O2, in turn protozoa provide protection, mortility, CO2 and other growth factors. The presence of  Chlorella  within  Paramecium  helps to survive protozoa in anaerobic condition as long as there is sufficient light. K R MICRO NOTES 18

19. Mutualism K R MICRO NOTES 19

20. Mutualism K R MICRO NOTES 20

21. Mutualism K R MICRO NOTES 21

22. The Phosphorus Cycle  K R MICRO NOTES 22

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