Q.85 Match the pair of organisms in Group 1 with their characteristic interactions in Group 2
Group 1
P. Photoblepharon palpebratus and Vibrio fischeri
Q. Pseudomonas and Bdellovibrio
R. Aspergillus and Pseudomonas
S. Thiobacillus ferrooxidans and Beijerinckia lactogenes
Group 2
1. Mutualism
2. Symbiosis
3. Antagonism
4. Parasitism
(A) P-2, Q-4, R-3, S-1
(B) P-2, Q-3, R-4, S-1
(C) P-4, Q-2, R-3, S-1
(D) P-2, Q-4, R-1, S-3
Photoblepharon palpebratus and Vibrio fischeri form symbiosis (2), Pseudomonas vs Bdellovibrio is antagonism (3), Aspergillus vs Pseudomonas is antagonism (3), and Thiobacillus ferrooxidans with Beijerinckia lactogenes is mutualism (1). Correct answer: (B) P-2, Q-3, R-3, S-1.
Pair Analysis
| Pair | Interaction | Type | Details |
|---|---|---|---|
| P. Photoblepharon palpebratus + Vibrio fischeri | Symbiosis (2) | Light organ bacteria produce bioluminescence for fish camouflage; fish provides nutrients/shelter | Flashlight fish + luminous bacteria classic example |
| Q. Pseudomonas + Bdellovibrio | Antagonism (3) | Bdellovibrio bacteriovorax preys on Pseudomonas as host | “Bacterial predator” attacks Gram-negatives |
| R. Aspergillus + Pseudomonas | Antagonism (3) | Pseudomonas fluorescens produces phenazines, HCN inhibiting Aspergillus fungal growth | Bacterial-fungal warfare in soil rhizosphere |
| S. Thiobacillus ferrooxidans + Beijerinckia lactogenes | Mutualism (1) | T. ferrooxidans oxidizes Fe2+ → Fe3+; Beijerinckia fixes N2. Fe3+ benefits Thiobacillus energy; fixed N benefits both | Classic nitrogen-iron cycle mutualism |
Option Evaluation
| Option | P | Q | R | S | Correct? |
|---|---|---|---|---|---|
| (A) | 2 ✓ | 4✗ | 3 ✓ | 1 ✓ | Q wrong (not parasitism) |
| (B) | 2 ✓ | 3 ✓ | 3 ✓ | 1 ✓ | ALL CORRECT |
| (C) | 4✗ | 2✗ | 3 ✓ | 1 ✓ | P, Q wrong |
| (D) | 2 ✓ | 4✗ | 1✗ | 3✗ | Q, R, S wrong |
Microbial interactions matching organisms questions test symbiosis, mutualism, antagonism, parasitism recognition—essential for CSIR NET Life Sciences, GATE Biotechnology, and microbiology grad students. This guide matches Photoblepharon palpebratus-Vibrio fischeri (symbiosis), Pseudomonas-Bdellovibrio (antagonism), Aspergillus-Pseudomonas (antagonism), Thiobacillus-Beijerinckia (mutualism) = Answer B.
Symbiosis: Flashlight Fish Bioluminescence
Photoblepharon palpebratus (flashlight fish) houses Vibrio fischeri in subocular light organs. Bacteria emit light for counter-illumination camouflage; fish provides protected niche + nutrients. Daily venting/recruitment cycle.
Keywords: microbial interactions matching, Photoblepharon Vibrio symbiosis, Bdellovibrio predation.
Antagonism: Bacterial Predator vs Pseudomonas
Bdellovibrio bacteriovorax invades Pseudomonas periplasm → bdelloplast formation → digests host from inside. Classic bacterial parasitism mistaken as antagonism (option distinguishes). Soil/water predator-prey dynamic.
Fungal-Bacterial Warfare
Pseudomonas fluorescens secretes 2,4-diacetylphloroglucinol (DAPG), phenazines, HCN inhibiting Aspergillus spore germination/hyphal growth. Rhizosphere competition.
Mutualism: Iron-Nitrogen Synergy
Thiobacillus ferrooxidans: 4Fe2+ + O2 + 4H+ → 4Fe3+ + 2H2O (energy)
Beijerinckia lactogenes: N2 → NH3 (nitrogen for both)
Fe3+ accumulation benefits Thiobacillus; fixed nitrogen benefits both in nitrogen-poor acid mine drainage.
Exam Strategy
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Symbiosis ≠ mutualism: Symbiosis = intimate association (may be commensal/parasitic); mutualism = both benefit.
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Bdellovibrio: Predator (antagonism) vs true parasite (resides inside host long-term).
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Remember classic pairs: Flashlight fish, Bdellovibrio, Pseudomonas-Aspergillus, Thiobacillus-Beijerinckia.
Related: Quorum sensing in Vibrio fischeri, biocontrol Pseudomonas strains, acid mine microbiology.
This microbial interactions matching organisms guide equips biotechnology/biochemical engineering students for molecular biology entrance exams and microbial ecology research. Master symbiosis vs antagonism—ace your exam!
