1 Departments of Zoology, 3 Biotechnology & Bioinformatics and 2 Bioinformatics Centre, North- Eastern Hill University, Shillong, 793022 Email: - [email protected]Phylogenetic reconstruction using secondary structures and sequence motifs of ITS2 rDNA of Paragonimus westermani (Kerbert, 1878) Braun, 1899 (Digenea: Paragonimidae) and related species P. K. Prasad 1 , V. Tandon 1 , D. K. Biswal 2 , L. M. Goswami 1 and A. Chatterjee 3 8 th th International Conference 0n Bioinformatics, 7 – 11 September 2009, Biopolis, Singapore International Conference 0n Bioinformatics, 7 – 11 September 2009, Biopolis, Singapore
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1 Departments of Zoology, 3 Biotechnology & Bioinformatics and 2 Bioinformatics Centre, North-Eastern Hill University, Shillong, 793022 Email: - [email protected].
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1Departments of Zoology, 3Biotechnology & Bioinformatics and 2Bioinformatics Centre, North-Eastern Hill University, Shillong, 793022
Phylogenetic reconstruction using secondary structures and sequence motifs of ITS2 rDNA of Paragonimus westermani (Kerbert, 1878) Braun, 1899 (Digenea:
Paragonimidae) and related species
P. K. Prasad1, V. Tandon1, D. K. Biswal2, L. M. Goswami1 and A. Chatterjee3
88thth International Conference 0n Bioinformatics, 7 – 11 September 2009, Biopolis, Singapore International Conference 0n Bioinformatics, 7 – 11 September 2009, Biopolis, Singapore
• P. westermani (Kerbert, 1878) - Best known species, human parasite that can undergo development in >16 different snail species and 50 crustacean species.
• Status of prevalence and host range in India- not well documented.
Paragonimus
Egg80-110×48-60µ
Encysted metacercaria ~300- 400µ
Pre-adult Adult: 7.5-12 × 4-6×1-3mm (l: w = 2:1)
• Zoonotic lung fluke having diversified effect on its final host. • Over 40 species infect lungs of different mammalian hosts.• ~15 species known to infect humans.
88thth International Conference 0n Bioinformatics, 7 – 11 September 2009, Biopolis, Singapore International Conference 0n Bioinformatics, 7 – 11 September 2009, Biopolis, Singapore
Distribution of human paragonimiasis
Species of Paragonimus are encountered in Asia, the Americas, and Africa.
88thth International Conference 0n Bioinformatics, 7 – 11 September 2009, Biopolis, Singapore International Conference 0n Bioinformatics, 7 – 11 September 2009, Biopolis, Singapore
Distribution in India
88thth International Conference 0n Bioinformatics, 7 – 11 September 2009, Biopolis, Singapore International Conference 0n Bioinformatics, 7 – 11 September 2009, Biopolis, Singapore
1. P. westermani (Kerbert,1878)- Bengal tiger, Amsterdam Zoo collection from India, Indonesia, China[ Syn. P. edwardsi Gulati, 1926- civet]
2. P. compactus (Cobbold, 1859)- Herpestes edwardsii India (Vevers,1923; Ravikumar et al.,1979); Sri Lanka (Dissanaike and Paramananthan, 1962)
3. P. heterotremus Chen and Hsia, 1964- China, Thailand,
Laos, Vietnam
• Arunachal Pradesh (Narain et al. 2003)
• Manipur (Singh,1996)
4. P. hueitungensis Chung et al.,1975- China
• Manipur (Singh, 2002)
5. P. mungoi, P. pantheri – Orissa (Mishra et al.,1976)-
nomen nudem88thth International Conference 0n Bioinformatics, 7 – 11 September 2009, Biopolis, Singapore International Conference 0n Bioinformatics, 7 – 11 September 2009, Biopolis, Singapore
Paragonimus species: India
1. Infective stage: metacercaria2. Infective mode: eating raw fresh water
crabs and crayfish with metacercariae3. Infective route: by mouth4. Site of inhabitation: lungs
Many other species described. Nearly 50 species, mostly in Asia:
over half of these in China alone. This prompted a molecular
taxonomy approach.
(P. westermani not shown here)
88thth International Conference 0n Bioinformatics, 7 – 11 September 2009, Biopolis, Singapore International Conference 0n Bioinformatics, 7 – 11 September 2009, Biopolis, Singapore
Molecular Taxonomy
• Molecular tools- allow quick and accurate identification of genetically distinct but morphologically similar species
• Genetic markers in nuclear ribosomal DNA (rDNA) - to resolve taxonomic issues related to various animal groups - to find phenotypic variants, geographical isolates
• ITS rDNA– widely used region, to explore species boundaries in at least 19 digenean (helminth parasites’) families
88thth International Conference 0n Bioinformatics, 7 – 11 September 2009, Biopolis, Singapore International Conference 0n Bioinformatics, 7 – 11 September 2009, Biopolis, Singapore
The ribosomal DNA gene cluster
• Ribosomal genes and their associated spacers are among the most versatile sequences for phylogenetic analysis.
• Useful for diagnostic purposes at the level of species.
88thth International Conference 0n Bioinformatics, 7 – 11 September 2009, Biopolis, Singapore International Conference 0n Bioinformatics, 7 – 11 September 2009, Biopolis, Singapore
88thth International Conference 0n Bioinformatics, 7 – 11 September 2009, Biopolis, Singapore International Conference 0n Bioinformatics, 7 – 11 September 2009, Biopolis, Singapore
• ITS sequence motifs- useful for development of DNA bar coding; short DNA sequences from a standardized region of genome- diagnostic “biomarker” for species identification
(http://www.barcoding.si.edu/)
• Molecular morphometrics- - traditional morphological and molecular sequence comparisons by measuring structural parameters.
- Geometrical features, bond energies, base composition etc. of secondary structure to study phylogenetic relationships of species
(http://www.bioinfo.rpi.edu/applications/mfold)
88thth International Conference 0n Bioinformatics, 7 – 11 September 2009, Biopolis, Singapore International Conference 0n Bioinformatics, 7 – 11 September 2009, Biopolis, Singapore
Materials & Methods
Parasite:
• Collected from mountain stream crabs of suspected
focal area (Changlang Dist. in Arunachal Pradesh).
• Metacercariae isolated from muscles by digestion
technique.
DNA isolation:
• DNA extracted in FTA card (Whatman’s), punching
sample discs
• Sample discs- washed with FTA Purification reagent and
TE Buffer; used for PCR.
88thth International Conference 0n Bioinformatics, 7 – 11 September 2009, Biopolis, Singapore International Conference 0n Bioinformatics, 7 – 11 September 2009, Biopolis, Singapore
[Designed based on conserved sequences of the 5.8S and 28S genes of Schistosoma spp]
• Marker- Phi X 174 DNA/ Hae III Digest in agarose gel
• PCR products- purified by Genei Quick PCR Purification Kit; - sequenced in both directions using primer set 3S-A28
88thth International Conference 0n Bioinformatics, 7 – 11 September 2009, Biopolis, Singapore International Conference 0n Bioinformatics, 7 – 11 September 2009, Biopolis, Singapore
Molecular Phylogenetic Analysis
• Only unique sequences were used in tree construction.
• ITS sequences entered in MEGA for phylogenetic trees construction.
• Tree building methods- Maximum Parsimony, Neighbor-Joining, UPGMA,
Minimum Evolution. • Branch support given using 1000 bootstrap replicates in MEGA
Bayesian Phylogenetic Analysis
• Sequences aligned using Clustal W 2.0.7 and converted to NEXUS file.
• Analysis carried out with combined datasets using Mrbayes 3.1.
• Cladogram and phylogram with mean branch lengths generated, and read by Tree view V1.6.6.
88thth International Conference 0n Bioinformatics, 7 – 11 September 2009, Biopolis, Singapore International Conference 0n Bioinformatics, 7 – 11 September 2009, Biopolis, Singapore
Motif identification, testing and validation
• Sequences motifs identified from aligned sequences of the data set using PRATT software.
• Motifs were expressed using DNA alphabet (A,T,C,G) in PROSITE language.
• Validation of motifs were performed for each species using a ‘PATTERN MATCHING’ web application.
Evaluation through BLAST analysis
• Sequences motifs subjected to BLAST algorithms against nonredundant GenBank database of NCBI (nr).
• BLAST outputs analyzed to find perfect pair-wise matches in terms of percent identity and E-values for each species.
88thth International Conference 0n Bioinformatics, 7 – 11 September 2009, Biopolis, Singapore International Conference 0n Bioinformatics, 7 – 11 September 2009, Biopolis, Singapore
Predicted ITS2 RNA secondary structures and analyses
• Secondary structures of ITS2 sequences of various paragonimid species were reconstructed by aligning their sequences using Bioedit (Hall, 1999).
• The acquired structures with restrictions and constrains submitted in MFOLD (Zuker, 2003).
• RNA structure chosen from different output files with highest negative free energy for various similar structures obtained.
88thth International Conference 0n Bioinformatics, 7 – 11 September 2009, Biopolis, Singapore International Conference 0n Bioinformatics, 7 – 11 September 2009, Biopolis, Singapore
M 1 2 3 4 5 6
1b
PCR products of Paragonimus metacercaria DNA using primer set 3S - A28 for ITS2
Results
Product size: ~ 500 bp
Final reaction volume = 50μl1.6% agarose gel electrophoresisMarker = Ø x 174 DNA/ HaeIII Digest
PCR amplification and analysis
Amplification conditions:
Initial denaturation at 94ºC =1 minDenaturation at 94ºC = 30 secAnnealing at 55ºC = 38 secExtension at 72ºC = 42 secFinal extension at 72ºC = 10 min
}26 cycles
88thth International Conference 0n Bioinformatics, 7 – 11 September 2009, Biopolis, Singapore International Conference 0n Bioinformatics, 7 – 11 September 2009, Biopolis, Singapore
88thth International Conference 0n Bioinformatics, 7 – 11 September 2009, Biopolis, Singapore International Conference 0n Bioinformatics, 7 – 11 September 2009, Biopolis, Singapore
Sequence motif in PROSITE format (from 5’ to 3’ ends)
88thth International Conference 0n Bioinformatics, 7 – 11 September 2009, Biopolis, Singapore International Conference 0n Bioinformatics, 7 – 11 September 2009, Biopolis, Singapore
Phylogenetic trees of ITS2 sequences of Paragonimid species. (*) = Query sequence
NJ tree
MP tree
BLAST outputs of Paragonimus ITS sequence motifs against NCBI GenBank databaseSpecies motif patterns (5’-3’ ends) Length (bp) No. of best hits Identity
88thth International Conference 0n Bioinformatics, 7 – 11 September 2009, Biopolis, Singapore International Conference 0n Bioinformatics, 7 – 11 September 2009, Biopolis, Singapore
88thth International Conference 0n Bioinformatics, 7 – 11 September 2009, Biopolis, Singapore International Conference 0n Bioinformatics, 7 – 11 September 2009, Biopolis, Singapore
Predicted ITS2 RNA secondary structures with enthalpies: Indian isolates
88thth International Conference 0n Bioinformatics, 7 – 11 September 2009, Biopolis, Singapore International Conference 0n Bioinformatics, 7 – 11 September 2009, Biopolis, Singapore
Predicted ITS2 RNA secondary structures: Neighbouring countries isolates
Family Paragonimidae: Hypothetical Bayesian analysis phylogeny based upon secondary structure alignment data of ITS2
88thth International Conference 0n Bioinformatics, 7 – 11 September 2009, Biopolis, Singapore International Conference 0n Bioinformatics, 7 – 11 September 2009, Biopolis, Singapore
Discussion
• ITS sequences- high species-specific homogeneity.
• Primary sequence analysis-
close relationship between query sequence (P. westermani from India) and isolates of related species from neighbouring countries.
• Secondary structure analysis-
provided additional information for correct identification of the species.
confirmed the results from primary sequence analysis.
88thth International Conference 0n Bioinformatics, 7 – 11 September 2009, Biopolis, Singapore International Conference 0n Bioinformatics, 7 – 11 September 2009, Biopolis, Singapore
• ITS sequence motifs
All the sequence motifs were available in all the Paragonimus sequences of different geographical isolates under study.
Validation of motifs showed high percent identity and low E-value scores.
88thth International Conference 0n Bioinformatics, 7 – 11 September 2009, Biopolis, Singapore International Conference 0n Bioinformatics, 7 – 11 September 2009, Biopolis, Singapore
Conclusion
• The Paragonimus species prevalent in the region is in fact Paragonimus westermani, the most common lung fluke throughout the globe.
• ITS2 sequences:- - reliable tool to identify species and phylogenetic
relationships - potential as species markers.
• Different geographical isolates of Paragonimus spp need further study with additional molecular markers and barcoding to ascertain intra-specific strain variations, if any.
88thth International Conference 0n Bioinformatics, 7 – 11 September 2009, Biopolis, Singapore International Conference 0n Bioinformatics, 7 – 11 September 2009, Biopolis, Singapore
DST, DBT, CSIR (GOI)- for Travel Fellowship for InCoB2009.
DIT Project to VT. AICOPTAX programme (MoE&F, GOI) to VT DBT Project to VT & AC.
DSA programme (UGC-SAP) in Zoology; UPE (Biosciences) programme in School of Life Sciences,
NEHU, Shillong.
Co-ordinator, Bioinformatics Centre, NEHU.
Acknowledgements
88thth International Conference 0n Bioinformatics, 7 – 11 September 2009, Biopolis, Singapore International Conference 0n Bioinformatics, 7 – 11 September 2009, Biopolis, Singapore