Prajapati and Senan

instructed path and results are delineated below.

Partial Gene sequencing

Aȱ validȱ schemeȱ forȱ theȱ identificationȱ ofȱ aȱ probioticȱ strainȱ shouldȱ beȱ

currently based on its morphological, physiological, and biochemical

featuresȱasȱwellȱasȱonȱaspectsȱofȱitsȱgeneticȱprofile. The 16S rRNA presents

the most common target region for phylogenetic analysis at the species

level, because sequence data of this region can be used for taxonomic

classification.ȱ The partial 16S rRNA gene sequencing was outsourced to

MTCC, Institute of Medical Technology, Chandigarh, India. The sequence

was analyzed using the Basic Local Alignment Search Tool. After which

theȱgeneȱsequencesȱwereȱsubmittedȱtoȱGenBankȱandȱtheȱaccessionȱnumbersȱ

wereȱ dulyȱ receivedȱ andȱ strainsȱ wereȱ submittedȱ atȱ theȱ Internationalȱ

Depository, MTCC, Chandigarh. Genotyping revealed that the strains were

Lactobacillus helveticus and not previously assumed Lactobacillus acidophilus .

This is not surprising as the‘ L. acidophilus complex’ is a group of several

species including L.acidophilus , L. amylovorus , L. crispatus , L. gallinarum ,

L. gasseri , L.helveticus and L. johnsonii ȱ thatȱ wereȱ initiallyȱ identifiedȱ asȱ L.

acidophilus strains .

Whole Genome sequencing:

The rational next step was to go for whole genome sequencing of the strain.

Genome sequencing of a probiotic strain also constitutes an essential

step to generate primary information for the functional analysis of gene

and protein expression, reconstruction of metabolic pathways, cellular

transport etc. Genomics-based approaches and post genomic tools will

also facilitate the detailed investigation of the interactions between the

bacterium and its host organism by gaining an insight into the genes that

contribute to this gut functionality, and exploitation of this information

willȱleadȱtoȱaȱmoreȱcompleteȱunderstandingȱofȱtheseȱbeneficialȱmicrobes,ȱ

theirȱbehaviourȱinȱtheȱhumanȱgutȱandȱtheirȱeffectsȱonȱhumanȱhealthȱandȱ

will provide a major impetus for the development of probiotic foods by

supportingȱ claimsȱ concerningȱ theirȱ healthȱ benefits.ȱ Demandȱ forȱ faster,ȱ

affordableȱDNAȱsequencingȱhasȱledȱtoȱtheȱdevelopmentȱofȱso-calledȱ“nextȱ

generation” sequencing technologies like 454 Genome Sequencer (GS) FLX

instrumentȱfromȱRocheȱAppliedȱSciences.ȱItȱhasȱaȱsignificantȱadvantageȱ

over Sanger sequencing that it requires no gels or capillaries to separate

extension products by size, and that base incorporation can be detected in

real time. The complete sequence of the L. rhamnosus MTCC 5462 genome

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