Bioluminescence

• Bioluminescence - the emission of light from a living organism
• Biological Functions of Bioluminescence

  • Mating
  • Predation
  • Defense against Predators
• Mating and Predation

  • Photuris sp. female lures males from other species and devours them
• Defense against Predators

  • Noctiluca sp.
  • The Burglar Alarm Theory
• Bioluminescence for Countershading

  • The squid nurtures the bacteria to use the light they produce to countershade - a form of camouflage - against moonlight. The squid hunt at night and countershading hides them from their prey and perhaps predators
• The bobtail squid has a light organ that contains the Vibrio fischeri (which is responsible for the bioluminescence
• • Low cell density - no bioluminescence
  • High cell density - bioluminescence
• Quorum Sensing - A process by which bacteria communicate with each other to coordinate their behavior
• Sensory Information Flow

  • The signal will be accepted into the cell by the receptor. Once integrated in the DNA, there will be action (bioluminescence)
• Autoinducer: A substance causing autoinduction; especially an extracellular molecule produced by a population of microorganisms which induces a particular process in the population as a whole once a sufficient concentration is reached.
• Autoinducer-1 - for intra-species signal (specific strain)

  Autoinducer-2 - for inter-species signal
• Lux genes - group behavior genes
• We fight pathogens through (1) Antibiotics (2) Vaccines (3) Quorum Quenching
• Plasmid - carry genes for antibiotic resistance
• Plasmids - extrachromosomal small circular DNA molecules that replicate separately from the bacterial chromosome
• Porphyranases - Porphyra spp. (nori), a seaweed commonly eaten in sushi
• Seaweeds make an important contribution to the daily diet in Japan (14.2 g per person per day)
• Quorum Quenching - use of a rational drug design based on the autoinducer structure; as a result, there will be high cell density but is non pathogenic since communication is disrupted
• Interference with Quorum Sensing Signals

  1. Blocking signal reception
  2. Enzymatic degradation of the signal molecule
• Isolated Photobacterium leiognathi were found to be ampicillin and penicillin resistant!
• Some bioluminescent bacterial isolated from the aquacultured M. charruana (mussels) and Crassostrea sp. (oysters) were ampicillin resistant
• Bioluminescent mushrooms - Mycema chlorophos
• Bioluminescent forest litters

  • Ganoderma sp.
  • Polyporus sp.
  • Trametes sp.
  • Cerrena sp.
  • Mycena chlorophos
• Lepidoptera - macroinvertebrate with light
• Enzymes that can degrade signal molecule

  • Lactonase
  • Acylase
• Conjugation - the transfer of DNA between bacteria by a conjugative plasmid