1. Biotechnology Applications
| Organism | Kingdom/Group | Application | Mechanism |
|---|---|---|---|
| Saccharomyces cerevisiae (yeast) | Fungi — Ascomycetes | Bread making, alcohol fermentation, recombinant protein production | Anaerobic fermentation of glucose → + ethanol |
| Neurospora crassa | Fungi — Ascomycetes | Genetic research model (one gene – one enzyme hypothesis by Beadle & Tatum) | Biochemical mutant analysis |
| Trichoderma | Fungi — Deuteromycetes | Biological fungicide in agriculture | Produces antifungal compounds, mycoparasitism |
| Aspergillus niger | Fungi — Ascomycetes | Industrial production of citric acid | Organic acid fermentation |
| Nostoc, Anabaena | Cyanobacteria — Monera | Biofertiliser in rice paddies (nitrogen fixation) | Heterocyst-based nitrogenase activity |
| Diatoms (Chrysophytes) | Protista | Diatomite for filtration, polishing, pest control | Siliceous frustule properties |
| Methanobacterium | Archaebacteria — Monera | Biogas production in anaerobic digesters and landfills | Methane generation from organic matter |
2. Medical/Clinical Applications
| Organism/Agent | Disease Caused | Significance |
|---|---|---|
| Plasmodium (protozoan — Sporozoa) | Malaria (4 species: P. vivax, P. falciparum, P. malariae, P. ovale) | Most important parasitic disease globally |
| Trypanosoma (protozoan — Flagellata) | African sleeping sickness (T. brucei), Chagas disease (T. cruzi) | Vector-borne protozoal diseases |
| Entamoeba histolytica (Sarcodina) | Amoebic dysentery | Waterborne disease |
| Mycoplasma | Atypical pneumonia, plant diseases | No cell wall → resistant to penicillin |
| Prions (misfolded proteins) | BSE (mad cow disease), Creutzfeldt-Jakob disease (CJD) | No nucleic acid — novel infectious mechanism |
| Claviceps purpurea (Ascomycetes) | Ergotism — causes gangrene and hallucinations | Historical grain contamination disease |
| Puccinia (Basidiomycetes) | Wheat rust — major crop disease | Billions in agricultural losses annually |
3. Ecological Applications
| Concept | Ecological Role | Example |
|---|---|---|
| Lichens as bioindicators | Signal air quality ( sensitivity) | Absence of lichen = air pollution present |
| Fungi as decomposers | Nutrient cycling in ecosystems | Break down lignin and cellulose |
| Mycorrhizal fungi | Enhance plant nutrient (P, N) uptake | Ectomycorrhizae in forest trees |
| Dinoflagellate red tides | Cause shellfish toxicity and fish kills | Gonyaulax producing saxitoxin |
| Cyanobacteria in symbiosis | Fix atmospheric in Azolla (water fern) | Agricultural significance in paddy fields |