A species of algae previously reported to inhabit the seas around the British Isles and the East China Sea has now been found thriving in the Indian Ocean. The algae belong to a type known as endophytic — meaning they are microscopic in size and found living inside macroscopic seaweeds. Belonging to the species, Ulvella leptochaete, they are believed to confer ecological advantage to the host such as disease resistance. The discovery in the Indian Ocean gains significance because these algae may very well be an important source of anticancer compounds such as Taxol and this discovery may contribute in anticancer drug development.
Taxol, or Paclitaxel, is a well known anti cancer drug currently in use for many cancers including ovarian cancer, breast cancer, lung cancer and pancreatic cancer. Most of the marine endophytes produce taxol, although no confirmation exists for the Ulvella leptochaete .
A team led by Dr. Felix Bast, Assistant Professor, Central University of Punjab, Bathinda has recently published the results in the Journal of Biosciences . The research involved analysis of green seaweeds, Cladophora glomerata collected from Calicut, Kerala and red seaweeds, Laurentia obtusa collected from Mandapam, Tamil Nadu.
The researchers were able to discover the microscopic endophytic alga within its host seaweeds using advanced microscopes. Subsequently, researchers extracted and sequenced a small genomic region called Internal Transcribed Spacer, which is a routinely used DNA barcode for aquatic plants, and compared the sequence information with the global DNA sequence database NCBI-GenBank to confirm the identity of the endophytic algae. Further, they reconstructed molecular evolutionary legacy of this alga using computational phylogenetics, to reconfirm the identity.
“DNA sequencing is a technique for reading the code of DNA. As you know, DNA consists of four letter alphabets, A, T , G & C. These are nucleotide bases. These are linearly arranged to form genes that in turn code for proteins, and our entire life. If we know the code of a particular gene precisely by means of sequencing, the code can be used as a barcode to confirm the species identity. For example, gene coding for cox — an enzyme — is a standard barcode for animals. From unknown blood sample, we only have to sequence this gene and compare with DNA database to determine to which animal the blood belongs,” noted Dr. Bast in an email to this Correspondent.
“Phylogenetics involves the construction of a tree for the depiction of evolution. We used DNA sequence of endophytic algae and compared it with closely related species to arrive at a definitive conclusion on its taxonomic identity,” he added.
