Detail about bioluminscence sea animals and bacteria etc.,

1. “Bioluminescence Microorganisms”
P.DIVAKARAN
M.sc BIOCHEMISTRY & MOLECULAR BIOLOGY
PONDICHERRY UNIVERSITY
PUDUCHERRY.
BY

2. Introduction
 Bioluminescence is the production and emission of light by a living organism
as the result of a chemical reaction during which chemical energy is converted
to light energy..

3.  Bioluminescence, or the ability of an organism to create light, is one of nature’s most amazing
phenomena, seemingly drawn more from science fiction than science and natural history.
 While only a few land dwellers, like fireflies and some fungi, can make their own light,
bioluminescence is very common in the deep sea. Bacteria, jellyfish, starfish, clams, worms,
crustaceans, squid, fish, and sharks are just some of the groups of marine animals that have
bioluminescent members.
 All bioluminescent organisms use a reaction between an enzyme and a substrate to make light, but
different species use different chemicals in the process. This suggests that the ability to make light
evolved many times throughout the ages. In fact, it is estimated that luminescence has evolved
independently at least 40 times.
 Deep-ocean environments are almost completely dark; yet light is still important in these environments.
Thus, bioluminescence may provide a survival advantage in the darkness of the deep sea, helping
organisms find food, assisting in reproductive processes, and providing defensive mechanisms.

4.  However, although many marine species are able to produce this “living light,”
very little is known about specific ways that deep-sea organisms use this
ability.
 turning on bright lights can cause mobile animals to move away and may
permanently blind light-sensitive sight organs

5. Bacterial bioluminescence
Bioluminescence in the visible spectrum area is a mysterious natural
phenomenon. This is a feature of living organisms occupying various
branches of the evolutionary tree.
organisms can be found in aquatic ecosystems. The process of emitting light
by living organisms is based on chemi-luminescence resulting from the
formation of an electronically excited intermediate in the course of enzyme.
 Reaction by the emission of visible light with certain wavelength, intensity
and duration. The participation of highly specific protein biocatalysts (enzymes
- luciferases)

6. luminous bacteria are the most widely distributed light-emitting organisms with
the majority existing in seawater and the remainder living in the terrestrial or
freshwater environment. While most species of luminescent bacteria are
capable of living free, the majority are found in nature associated in symbiosis
with host organisms (Figures 1 to 4) (i.e., fishes, squids, crabs, nematodes,
etc...).
Pinecone fish

7.  In symbiosis, the bacteria are nourished with readily available food
sources for growth, and at the same time the host utilizes the adopted
illumination to communicate, to attract prey, and to masquerade itself
from predators.
 The deep sea Angler fish carries luminous bacteria in a
light emitting rod, which attracts prey to the front of its
mouth.

8.  However, there are certain species of luminescent bacteria, which are obligatory
symbionts, requiring unique nutritional supplements, which are exclusively
available from the host.
 Although the presence of these obligatory symbionts has been detected, they are
not separable from their host, and therefore are unable to be cultured in the
laboratory for further study.
There are three major genera, into which most luminous bacteria are
classified; Photobacterium, Vibrio, and Photorhabdus.
 Species existing in the marine environment are mainly categorized into
the Photobacterium and Vibrio genera,

10.  Many luminous bacteria are parasitic, with Photo bacterium and Vibrio families infecting
marine crustacea, and Photorhabdus luminescens infecting terrestrial insects, such as
caterpillars, with nematodes as the intermediate host for the bacteria.
 In addition, free-living luminous bacteria that are dispersed in the seawater can often be found
in both the gut tract and on the skin surface of almost all marine animals as non-specific
parasites.
Infection with the terrestrial luminous bacteria
(Photohabdus luminescens) is pathogenically
lethal to the caterpillar

11.  Each species of luminous bacteria differs in a number of properties, including the
specific growing conditions (nutritional requirements and growth temperature).
 The reaction kinetics of the luciferase involved in light generation; however, all
luminous bacteria are rod-shaped, gram-negative microorganisms with flagella
facilitating motion.
 Luminous bacteria are also facultative anaerobes capable of growth when the
supply of molecular oxygen is limited.
 Despite the physiological diversity among different species of luminous
bacteria, all luminescent microorganisms utilize highly homologous biochemical
machineries to produce light.
 The onset and the energy output of this light-producing molecular machinery are
tightly regulated under a central signaling pathway.

12. Bacterial groups that exhibit bioluminescence

13. Bacterial luminescence. Colonies of P. mandapamensis from the light organ of the
cardinalfish Siphamia tubifer (Perciformes: Apogonidae) are shown growing on a
nutrient seawater agar plate. The plate was photographed in room light (left) and
(the same plate) in the dark by the light produced by the bacteria (right)

14. Biochemistry of Bacterial Luminescence
Light emission in bacteria is catalyzed by a uniquely bacterial kind of luciferase.
 a heterodimeric protein of approximately 80 kD, composed of a (40 kDa) and b (37 kDa)
subunits, with homology to long-chain alkane monooxygenases .
The enzyme mediates the oxidation of reduced flavin mononucleotide (FMNH2) and a long-
chain aliphatic (fatty) aldehyde (RCHO) by O2 to produce blue-green light according to the
following reaction.

15. The Utilization of Bacterial Bioluminescence as a Biosensor and Reporter of Gene
Expression.
The "insertion" of the foreign lux CDABE structural genes into the organism allows the fatty acid reductase enzyme
complex and luciferase to be expressed, and the function of luciferase confers the organism the ability to emit light.
As the primary function of bacterial luciferase is to catalyze the emission of light, this feature
together with generation of the aldehyde substrate by fatty acid reductase can be successfully
produced in other bacteria, by the transfer of the luxCDABE genes, which convert
nonluminescent bacteria into light emitters.

16. The ecological significance of bioluminescence.
The function of light emission in higher organisms usually falls under 3 categories:
To assist in predation (offense), to aid in avoiding predators (defense) and for
intraspecies communication such as courtship. While the functions of luminescence are
quite clear for higher organisms.
 The ecological significance of bacterial and fungal luminescence is less
straightforward. Bacterial bioluminescence predominates in marine ecosystems,
particularly among fish.

17.  Studies of marine bioluminescence have provided great understanding on symbiotic
relationships particularly from the Euprymna scolopes-V. fischeri mutualism .
 The squid has specialized organs in which the luminous bacteria grow and provides
behaviorally useful light that help attract pray to the squid.
 Upon bacterial colonization, these specialized organs undergo developmental changes
that would not take place in the absence of the bacteria.
 Once the relationship has been established, the squid maintains an acceptable
population of the symbiont by expelling 90% of the bacteria population every morning.
The expelled bacteria are viable and regrow flagella. In this manner, bacteria are given
room and board and helped in their dissemination so that both organisms benefit from
the association.

18.  The uses of bioluminescence and its biological and ecological significance for animals,
including host organisms for bacteria symbiosis, have been widely studied. Its benefits for
bacteria, however, still remain unclear.
 Evidence also suggests that bacterial luciferase contributes to the resistance of oxidative stress.
 The luxD mutants, which had an unaffected luciferase but were unable to produce
luminescence, showed little or no difference. This suggests that luciferase mediates the
detoxification of reactive oxygen.
 Bacterial bioluminescence has also been proposed to be a source of internal light in
photoreactivation, a DNA repair process carried out by photolyase.
 Experiments have shown that non-luminescent V,harveyi mutants are more sensitive to UV
irradiation, suggesting the existence of a bioluminescent-mediated DNA repair system.
ROLE

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Hughson, F.M. (2002) Structural identification of a bacterial quorum-sensing signal
containing boron. Nature 415: 545-549.
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resolution crystal structure of bacterial luciferase in low salt conditions. J. Biol. Chem. 271:
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Hastings, J.W., and Greenberg, E.P. (1999) Quorum sensing: the explanation of a curious
phenomenon reveals a common characteristic of bacteria. J. Bacteriol. 181: 2667-2669.
Reference

20. Thank you……