To 1954, to control insect and mite pests on

To make agricultural industry more productive and
profitable in face of rising costs we use pesticides to prevent attack of
various insects. Nowadays pesticides have an important role in maintaining
balance between food production and population. Pesticides have been used
worldwide for insect pest management. Among all form of chemical pesticides,
organochlorines are considered to be the most hazardous, they are very
persistent and non- degradable and add to the residue build up in the food
chain (Jaffery et al, 1990). Endosulfan is a widely used organochlorine
insecticide since 1954, to control insect and mite pests on a variety of field
like fruits, vegetable and non-food crops. It has been listed as one of the
persistent organic pollutant by Persistent Organic
Pollutants Review Committee (POPRC) during the Stockholm Convention. The POPRC
has recommended a ban on the use as well as production of endosulfan in several
countries (Santamaria et al 2011). However the presence of endosulfan has been
detected in the different environmental compartment such a soil and water
(Weber et al 2009; Sethunathan et al 2002).

Technical grade of endosulfan is
composed of two steriochemical isomers, alpha endosulfan (endosulfan I) and
beta endosulfan (endosulfan II) in concentration of approximately 70% and 30%
respectively. Alpha isomer was the more toxic than beta isomer (Wan et al
2004). Endosulfan is highly lipophilic, persistent organic
insecticide; it can lead to                                                                                                                                                                                                            bio
accumulation and bio magnifications, resulting in to harmful effect on target
and non-target organisms.  It is one of
the more toxic pesticides, responsible for many fatal pesticide poisoning
incidents around the world. Several studies summarising endosulfan can cause
biological effects that include endocrine disruption, neurotoxicity,
hepatotoxicity and genotoxicity along with increased oxidative stress and cell
death (Bajpayee et al 2006; Silva et al 2009; Sohn et al 2004). Endosulfan also
a xenoestrogen, it can imitate or enhances the effect of oestrogens (Varayoud,
2002) and it causing reproductive and developmental damage in both animals and
humans. Endosulfan shows a wide range of acute, sub chronic and chronic
toxicity in insect and mammals including human, its acute poisoning results in
a 30 % or higher death rate (Moon 2009).

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In
the recent years the US Environmental protection Agency and the EU classified
endosulfan as “highly hazardous”, while the world health organisation
classifies it as Class II “moderately hazardous”. Acute exposure to high levels
of endosulfan is known to cause poisoning and even death in humans (Usha and
Harikrishnan, 2005). Adverse and severe health effects on exposure to
endosulfan have been reported in communities in several countries including
India, South East Asia, Southern pacific and Sub-Saharan Africa (UNEP-GEF,
2002; UNEP-GEF, 2002a). A recent investigation on the long-term use of
endosulfan in a cashew plantation district in India reported severe health
problems and residual contamination in the area (Vankar et al., 2001).
It is a GABA gated chloride channel antagonist, inhibitors of Na+/ K+
and Ca2+ / Mg2+ ATPase, these enzymes are essential for
transport of ion across the membrane. The residual amounts of organochlorines
are cause inhibition of acetyl cholinterase activity in the target tissues and
effect Na+/ K+ ATPase, Ca2+ / Mg2+
ATPase activity of cells (Naqvi and Vaishnavi, 1993).

Toxicity
assay was performed to study the inhibition of growth and development and also
determine sub lethal concentrations of endosulfan, alpha endosulfan and beta
endosulfan. Inhibition of development was studied by founding percentage of
hatchability, pupation rate and emergence of the model organisms. Pre mature
aging of organisms has been implicated by the alteration in the expression of
regulation of a no. of genes con current with factor like xenobiotic exposure,
dietary habits etc. Heat shock proteins (hsp) are reported to function as
chaperons by orchestrating correct folding and unfolding of proteins. Hsp can
counter act proteo toxicity and favour stress resistance to the organisms which
may be casually linked to an increase in life span but it undergo functional
decline (Tower 2009, 2011).

Endosulfans
elicit oxidative stress by generation of free radicals and induce tissue lipid
peroxidation in mammals and other organisms (Comele koylu et al., 2000). An
organism experiences xenobiotic stress following to endosulfan exposure. Stress
production is one of the primary protective responses of an organism by
induction of specific set of stress genes called as heat shock genes whose
products are called stress proteins (heat shock proteins). During pesticide
intoxication free radicals can be changes in protein components of cells on the
protein profile. Synthesis and degradation of proteins are sensitive over a
wide range of conditions and show different physical and chemical
modulators.  The biological alterations
observed in an animal under chemical stress can be correlated with the
structural and functional changes of cellular proteins. Proteins hold the
unique position in the modulators of cells because of the proteinaceuos nature
of all the enzymes which mediate at various metabolic pathways. (Lehninger
2008, Harper 2006).

Stress protein has been proposed as sensitive
indicator of lethal exposure to contaminants in the environment. When the cells
are challenged with certain environmental stimulus such as temperature and
toxic chemiacals cause the induction of stress protein genes, the product of
which function in new protein folding and in long effect it cause phenotypic
change (Craig et al., 1989, Cruz-Rodrique, 2002). Several stress protein have
been shown to be induced by wide variety of stressors like hyperthermia, heavy
metal etc. stress proteins are placed in to groups of families based on their
relative in number and DNA sequence; like high molecular weight stress protein,
stress protein 70, chaperones 60, stress protein 42 and low molecular weight
stress proteins.

            Responses of organism against
endosulfan reflect an overall effect on population. It may be linked to
population dynamics where in characteristic like survival, development and
behaviour of exposed individual affected (Brunelli E. et al 2009; Lenkowski J.R
et al  2009). D. melanogaster was used to non-targeted insect model organism, because it
is an invertebrate model organism that is closest to humans and has wide
acceptability for genetic and developmental studies. During the last decade,
this model has been extensively used for elucidating human diseases and for
toxicological studies (Pandey S. et
al 2001, Rand M.D et al 2010).

The
study aims to determine median effective concentration (EC50) of
endosulfan, alpha endosulfan and beta endosulfan, to determine how much chemicals
are needed to kill half of a group of test organisms in a given time. And to examine the in vivo effect of endosulfan given to
Drosophila melanogaster in the diet to understand the stress protein expression,
protein profile changes with differentially expressed proteins in D.melanogaster treated with different
doses of endosulfan, alpha and beta endosulfan (the dose dependent stress
inducing potential of endosulfan and its isomers). The
study was further extended to examine the organismal response to this
insecticide, effect of endosulfan and its isomers on the life cycle of exposed
drosophila by examining the emergence pattern, hatchability and pupation. 

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