BIOLUMINESCENCE : BIOLUMINESCENCE Microbiology Slide 2: INTRODUCTION Luminescence- Means ability to emit light Bioluminescence- emission of light by a living organism is known as bioluminescence including bacteria, fishes,fireflies. Major property – major property of bio luminiscene is the presence of great diversity in an organism that have developed the abiltiy to emit light. Slide 3: Occurrence: Bacteria ,fungi,flagallates,snail,centipoles,insects,earthworms & fireflies
Bioluminescence's is very rare in occurrence in presence of luminous bacteria in symbiotic association on their body .
In case of cattle fishes, the luminous bacteria are located in special pouches, under the eyes
The pouches may be occurred with shutter system, permitting the fish to flash the light.
Light emitted by organism are visible, colored , narrow band of wave length
Bacteria produce blue green luminescence with wave length 400mm.
Fungi produce yellow green luminescence with wavelength 580mm.
Both of them produce light continuously .
While none of the higher plant is found to emit light , through they are very to marine emitting light. Slide 4: HABITAT Free living organism bacteria usually observed in sea water than in fresh open water bodies.
Saprophytes luminous bacteria can be observed .
If swab is collected from marine animals grown in a special medium with sea water base, then the growth of luminous bacteria can be observed with its luminiscence property .
If swab is collected from marine animals grown in a special medium with sea water base , then the growth of luminous bacteria can be observed with its luminescence property.
Freshly collected fishes , if allowed to stay for longer time, allowing bacterial growth, then such start to glow, showing the growth of luminous bacteria.
Stored meat and salted Hams also reported to s glow because of luminous bacteria.
Luminous bacteria also found in human wound Fungi – Luminous fungi are also found to be grown on cotton logs wood.
They found to be glowing brilliantly .
Most well known luminous fungus is panus stipticus Slide 5: Bacteria Before the electrical refrigerator into general use, there were often reports in news paper
About the “mystery meat “ giving of the light emission in because of luminous bacteria.
Recently these bacteria are classified in 0th edition of enery’s manual of systematic
Bacteriology . They are placed in volume 1 section 5.
These organism are classified in 4 main genera as:
IDENTIFIED ORGANISM ARE :-
photo bacterium phosphorous
photo bacterium leioguathi
nibrio eisheri Slide 6: MORPHOLOGY All are wave –ve , short thick rod arranged singly , or in pair or in short chains .
All are the motile with polar flagella .
Bacteria are found to store lipid granules and are chemo- organotrophic.
They can be cultivated in anaerobic condition but they require O2 for luminous property
Higher reaction concentration is required with optinum temperature 15- 20*c, incubation period 12-16 hrs . Slide 7: Functions Of Bioluminescence : -> Bio luminescence might be used as a tool to attract pray, which then can be captured .
-> It may be used as “search light “ in dark in deep sea .
->Bio luminescence may be useful to promote the schooling of animals. To give the instructions
-> It may be useful during mating to attract the life partner.
-> It may be useful as defense mechanism by changing the pattern of flashing, they can confuse the enemy MECHANISM : MECHANISM For each cycle of light emission, one mole of FMNH2 and one mole of NADH2 are required.
the light emitter complex is made up of an enzyme luciferase + oxygen + aldehyde+ FMNH2
Aldehyde addition occurs only often formation of complex L-FMNH2
In absence of aldehyde, the light emission is not observed.
Any mutant when looses the ability to synthesize aldehyde , automatically looses the ability to emit light.
During return to ground state, the mole oxygen cleaved, one oxygen mole is used for conversion of aldehyde to acid.
RCHO+O-------------RCOOH and mole is for formation of water
Long chain fatty acids are again oxidized to aldehyde, where one mole of NADH2 is utilized.
Long chain aldehyde is generally palmitaldehyde Luciferase enzyme : Luciferase enzyme It is a heterodimer made up of two subunits α,β with mole weight α-42000 Dalton & β-38000 Dalton.
These two protenic subunits are the product of “LUX” gene.
Luciferase activity requires large amount of ATP, it may be induced by mercury. Control of luminous activity : Control of luminous activity Auto induction
The luminescent system is controlled by the bacteria themselves.
“Auto inducer” is accumulated in cytoplasm, which stimulates the synthesis of components of luminescent property.
If any how auto inducer is not synthesized then because of lack of induction for synthesis of components of luminescent unit, leads to lack of luminescent property.
Composition of medium
Presence of arginine and high salt concentration are known to be essential for luminescent property.
The excretory product accumulation late in growth phase, effect the luminescent property .
If the bacteria are grown in medium with low buffered capacity, then because of
Accumulation of acid, the pH of medium decreases, also luminescent activity also decreases. Application : Application Luminous bacteria can be used as experimental tool to study or check the ability of any drug to act on cell’s respiration. It can be done by using photoelectric cell. If organism don’t show luminous activity after addition of drug, then it suggest that the drug acts on cell’s respiration.
The organism can also be use to detect the presence of oxygen even in small concentration.
It also can be used to quantify the amount of O2 evolved in photosynthesis
A cake of luminescent bacteria is used to attract and to catch big fishes in ocean.
LUX genes can be used as selective markers in genetic engineering process.