Due to the difficulty of isolating and culturing, many marine microorganisms are regarded as "viable but non-culturable" (VBNC). Which one of the…
Due to the difficulty of isolating and culturing, many marine microorganisms are regarded as "viable but non-culturable" (VBNC). Which one of the following is a suitable method to hunt for useful genes in these organisms?
Select an option to attempt
Correct Answer: Option D
Explanation
Metagenomics for studying unculturable marine microorganisms (VBNC):The VBNC (Viable But Non-Culturable) problem: estimated >99% of marine microorganisms cannot be grown in laboratory culture conditions — they have specific nutrient requirements, syntrophic partnerships, or pressure/temperature dependencies.Metagenomics solves this:1. Collect environmental seawater sample.2. Extract total community DNA directly (without culturing).3. Fragment and sequence using NGS (shotgun metagenomics) or 16S rRNA amplicon sequencing.4. Assemble sequences bioinformatically into contigs and MAGs (Metagenome-Assembled Genomes).5. Annotate genes from assembled contigs → discover novel genes and biosynthetic pathways.Alternatives and why they fail:• In situ cultivation: still requires growing cells; VBNC by definition won't grow.• Large bioreactor: also requires cultivation.• Barcode sequencing: identifies species but doesn't discover novel genes.Answer: Metagenomics — direct environmental DNA sequencing without culturing — is the only culture-independent method to discover genes from VBNC marine microorganisms.