Caenorhabditis elegans is a combination of Greek and Latin words intending Caeno, recent ; rhabditis, rod-like ; elegans, elegant. C.elegans is a little rounded, nonsegmental worm. Maupas ( 1900 ) was the first scientist to depict the worm from break uping dirt collected from Algeria ( Fatt, 1961 ) .The first categorization was published by Osche ( 1952 ) and after by Dougherty ( 1955 ) . They placed the worm in the subgenus Caenorhabditis, and generic position severally. Recent systematics based on morphometric and molecular informations placed the worm in the category of Scernentea, order of Rabditida, household Rabditidae ( Kiotke et al. 2004, De ley & A ; Blaxter, 2002. ) . There are two normally wild type strains used in scientific community: Bergerac and Bristol strains. The Bergerac was originally isolated from dirt sampled in Lion, France by Victor Nigon and L.N. Staniland collected the other, Bristol, from mushroom compost near Bristol, England. C. elegans is among 18 Caenorhabditis species to the full described in footings of their ecology ( Kiontke et al. 2005 ) .The worm was found as dirt dweller in break uping niches that are rich in food where it feeds on bacteriums and likely other micro-organisms. In research lab maintained environment, C.elegans can be grown on a figure of bacteria species but Escherichia coli was chosen as standard civilization nutrient in petri dish due to its efficaciousness. The worms can besides be grown in liquid civilizations viz. monoxenic and axenic civilization. For research lab efficaciousness and efficiency, worm is kept in stop deading liquid N at -196 0c ( Brenner, 1974 ) . In natural ecosystem, C. elegans lives in association with other dirt invertebrates with which it has different types of relation defined as phoresy and necronemy ( Caswell-Chen et al. , 2005 ; Kiontke and Sudhaus, 2006 ) .
Life rhythm. The two sexes are present in C.elegans: intersex worms that reproduce by either automic signifier or sexual reproduction and males. The sexes can be distinguished by morphological, anatomical and behavioral trials. The hermaphroditic animate beings are evidently bigger and female generative variety meats good developed exteriorly ( vulva slit ) , and the tapering tail form. The male organic structure is slender with sex specific features such coital variety meats, the centripetal beams and fan. In add-on, males show characteristic behavior with its fast distortion motions. Despite these differences, intersex and male portion some tissues, throat, excretory system and chief organic structure musculuss ( Nguyen et al. , 1999, Emmons, 2005 ) .
Hermaphrodite produces sperms that mature before the eggs, so that self-fertilisation occurs in the early reproduction. In this instance, the figure of fertilized eggs produced by intersex is about 300egges and so after the fertilisation occurs by cross-fertization with males to bring forth up to 1000 oocytes. It was noticed that males are really rare in C.elegans population by self-generated non-disjunction in the hermaphroditic germ line and the proportion increase up to 50 % through coupling.
C. elegans life rhythm is temperature dependant. At optimum conditions 25oC, the complete life rhythm is completeted in three yearss ( Ledoux, M. 2005 ) . The worm undergoes a development that takes four larval phases ( L1, L2, and L3, L4 larvae ) to make the maturity. The terminal of each phase is marked by a moult, but the normal development procedure may be interrupted under rough environmental conditions ensuing from high temperature, overcrowding and nutrient deficit. In this instance L2 larvae moults to bring forth a dauer, an alternate resistant L3 larvae signifier that resume life rhythm when conditions favourable. Dauer is a non-feeding, has a thickened and modified organic structure cuticle, the bowel is reduced, secretory-excretory secretory organ is inactive and there is alteration of centripetal variety meats. Interestingly, dauers can stay feasible for three months.
Anatomy. C.elegans has a transparent organic structure 1.2mm length and 50Aµm breadth.The organic structure shows a simplified form that refers to all roundworms construction ( Bird and Bird 1991 ) . The organic structure building consists of two tubings separated by a unstable pit incorporating functional variety meats. The outer tubing was described as protective walls strengthened externally by a collagenic extracellular matrix ( James M. et Al. 2007 ) . The interior one is an alimental channel, from anterior to posterior, a sequence of parts: throat, bowel, and rectum ( Fukushige T et Al 1996 ) . C.elegans ingests nutrient ( micro-organism ) by pumping utilizing the guttural musculuss made up by two lobes and fall ining portion to the bowel ( pharyngeal-intestinal valve ) that control the main course of nutrient into the bowel ( Susan E. Mango et Al. 2007 ) . The apical surfaces of the enteric are mounted with coppice construction -like cells, microvilli, that are believed to play a function in digestion ( Leung et al. 1999 ) . The enteric contents are excreted to the outside via a rectal valve that connects the intestine to the rectum and anus ( McGhee, 2007, Sewell, S.T. et Al. 2003 ) .
Nervous system.In grownup intersex C. elegans, a high proportion of its bodily karyon construct up its complex nervous system. In a entire figure of 959 cells, 302 have neural map and 56 neural support cells ( Hobert, 2005 ) . C.elegans nervous system comprises two subsystems: the bodily system with 282 nerve cells inserted in between hypodermis and the organic structure wall musculuss, the other, pharyngeal nervous system that count 20 karyon and all in tied connexion with their guttural musculuss. Pair of interneurons type connects the two neural systems ( White et al. , 1986 ) . Neuronal categorization based on specific anatomical characteristics, defined 118 nerve cell categories ( Hobert 2005 ) . Based on the functional grouping, C.elegans nerve cells are assembled into four groups: motor nerve cells, centripetal nerve cells, and interneuron. The two sexes have centripetal dimorphism that is of two types in male: male-specific and sexually dimorphous. In male C.elegans, the centripetal variety meats have no homology in the intersex and are formed by cell types generated merely in the male. Sexual dimorphous sense organs contain at least some cells that have the same direct beginning in both sexes. They express distinguishable differentiated features in the both sexes, reflected in cell morphology, and organisation ( ( Emmons, 2005 ) .
Reproduction. The generative system presents a sexual dimorphism between hermaphroditic worm and male. Hermaphrodite generative system is composed of bodily sex gland, the germ line and the egg-laying setup. It consists of two symmetric subdivisions folded into two U-shaped sex gland weaponries fused into a common womb by mean of spermtheca. Gonads develop from germ cells and the general organisation is completed at L4 larvae phase ( Newman et al. , 1996 ) . The male generative system arises from three types of cells: source line, bodily cells and neural cells. The male sex gland has three constituents: testicle, seminal cyst and vessel deferens.
C.elegans as theoretical account being. Brenner ( 1974 ) was the first scientist to propose C.elegans as theoretical account being for the survey of genetic sciences. He cited legion proficient advantages of working with C.elegans ( little, simple, easy to turn, short life rhythm, transparence of the organic structure, ) . Considerable figure of research workers followed the thought by utilizing the worm in different research country. The completion of, C. elegans has opened many doors to scientists. C. elegans genome sequence revealed high similarities with other eucaryotes. It portions most of the biological systems, feeding, nervous system, musculus, generative, with advanced being. It is easy handled in research lab and it reproduce quickly. Its crystalline organic structure makes every cell to be studied in populating carnal under microscope. This characteristic made the C. elegans an being easy the survey of cistron look forms utilizing the newsman cistrons green fluorescent protein ( GFP ) and i??GAL ( Boulin, T. et al. , 2006 ) . It is easy transformed with extra and remotion of cistrons ( RNAi ) . At the terminal of its life, it shows marks of ageing and so be a good campaigner for the survey of ageing procedure in other animate beings. However, the nematode theoretical account is non without its experimental challenges. C. elegans cells and variety meats are little when compared to their mammalian opposite numbers and they are enclosed within a pressurized and comparatively impermeable cuticle. This is rather disputing for in vivo electrophysiological analysis of channel map, peculiarly in nerve cells ( Bianchi, L. and Driscoll, M. , 2006 ) .iˆ iˆ®
