Transcript Part 2 - Laboratory of Aquaculture & Artemia Reference Center

Review on Artemia as Ultimate
model for Genomic research
Peter Marian. M 1,2
1 Marine Biotechnology Laboratory, ICAS of M.S
University, Rajakkamangalam, Kanyakumari District, Tamil
Nadu, South India
2 Institute for Artemia Research and Training, M.S
University, Rajakkamangalam, Kanyakumari District, Tamil
Nadu, South India
Abstract
This review claims attention of genomic researchers about a tiny
crustacean Artemia. Apart from serving as livefeed in aquaulture
industries, Artemia seems to be the ultimate model for several genomic
puzzles. Genomic research on Artemia at the molecular level is still in its
infancy and a complete genomic analysis is needed. Artemia has proved to
be a potential model for classical genetic studies in the past and molecular
level approaches are yet to be iniated such as functional genomics,
population genomics etc. Artemia shows well developed gene regulatory
system for its survival even under extreme conditions. Artemia seems to be
a promising system for stress response studies as observed in our
laboratory since it shows a swift adaptation to harsh environments. A
variety of Heat shock proteins (HSPs) were expressed which when
characterized will give a detailed information about its stress tolerance.
The cryptobiotic cysts of Artemia can remain viable for long period in
abnormal conditions like -irradiation, temperature, salinity and long-term
anoxia. Available data from genetic databases are also reviewed in this
paper and the status of Artemia genomic research in Indian subcontinent is
also discussed.
Life Cycle
18-24 days
Haploid genome size
0.9 x 1012 bp
Number of Chromosome
42 bisexual / parthenogenetic Artemia
46 in Artemia persimilis
Number of Mapped Markers
Parthenogenetic 94 RAPD
Bisexual – 27 RAPD 70 RAPD Primers
43 AFLP
Number of Cloned Genes
348
Mode of Reproduction
bisexual / parthenogenetic
Transgenesis
No
Mitochontrial genome size
15822 bp
Total Ribosomal rRNA gene copies
320 (18S + 26S)
Gene Bank Entries
508
IImportance of Artemia Genome project (ArGP)
 Extremophilic eukaryote lives comfortable in normal
conditions also

Will lay Foundation for Genetic improvement
programme

Swift adaptations to harsh and normal conditions
which can contribute enormous data to medical field.

To develop knowledge base on stress proteins and
molecular chaperones for human welfare
 Can contribute gene resource for saline stress proteins
to other eukaryotes
Gene expressions in abnormal conditions yet
characterized

In Quiescent embryos of the Artemia the level of aminoacylation of
tRNA is low and the expression of tRNA genes are dramatically reduced
(Brandsma et al., 1997).

Expression of P26 genes, (a family of HSPs) (Liang, et al., 1997)
 Lower expression of cytochrome c oxidase (COX 1) in anoxia which can
be activates by previous measures of COX1 catalytic activities (Hardewiz et
al., 1996).

Very low expression of Na+ / K(+) ATPase and Ca(2+) dependent
ATPase sense in Cryptobiosis

Reduced level of polysomes profiles for translational regulation

In continious anoixia protein P26 also behaves as GTPase to
regulate Diguanosine nuclecotide metabolism (Warner and Glegg,
Comparitive genomics of Artemia with other eukaryotes
 The mitochordrial genome of Artemia has the same coding capacity
as most animal mitochondrial genomes, and its overall organization is
similar to that of Drosophila (Carrodeguas and Vallego, 1997).
 Five intrance sequence 14 kb genomic clone of Ca(2+) – ATPase
genome of Drosophila melunegater are same position in Artemia
SERCA, Ca(2+) ATPase genes. (Maggar et al., 1995).

The comparision of Artemia sequence with both vertebrate and
invertebrate mitochondial 16S rDNA sequences has shown the
existence of regions of high similarity with them (Palmero et al., 1988).
 Similarity of the Artemia gene to insect rRNA in size, sequence and
secondary structure, the G + C content of the Artemia gene (42%) is
closes to that of mammals than the insect genes.
FFuture perspectives of Artemia genome research in IART
 Developing mitochondrial Genome data base for various species of Artemia
• AArtemia Gene Bank
 Expression profiling of cyst inducing genes
 Stress biochemistry and gene profile studies for chemical stresses
 Application of Microarray technology for High through put screnning and
expression of Genes in Artemia at abnormal conditions.
On going proteomic research at IART in Artemia on
-
saline stresses
cold shock, proteins
naturally and artificially induced cyst formation
strain characterization through molecular markers
cross breeding and genetic improvement programme
Conclusion
The molecular characterization of Artemia genome is poised on
the edge of a new era. The large collections of Artemia mutants
and practical breeding stocks are valuable resources that have
only begun to be exploited to full potential. The well-studied
gene resources of Artemia make it a ideal reference for the
Insecta where comparative genetics and genomics can work
together to elucidate conserved evolutionary pathways and their
divergence due to extreme adaptations, identify new genes and
gene systems as targets for transgenesis. Besides, it leads to
basic research on new genome based approaches for
exploitation of other species. Artemia genome project should be
initiated for development of tools for targeted knockouts.