AP BIOLOGY

Detailed explanation-1: -Bifidobacterium longum (B. longum), Salmonella enterica serovar typhimurium (S. typhimurium) and S. choleraesuis are facultative anaerobic microbes which can apply in the tissue of solid tumors for gene delivery.

Detailed explanation-2: -Stem cells provide two major benefits for gene and cell therapy. First, they provide a cell type that can self-renew and may survive the lifetime of the patient. Second, stem cells provide daughter cells that mature into the specialized cells of each tissue.

Detailed explanation-3: -Bacteria can be used for gene therapy via two strategies-either by transfection of eukaryotic host cells using bacteria (bactofection) or by alternative gene therapy that does not alter the host genome, but uses the prokaryotic expression system, which can be controlled or stopped from outside.

Detailed explanation-4: -In bactofection-based gene therapy, the bacterium is considered the ‘vector’, which mediates carriage of the plasmid-based gene to the new host cell. Delivery of genetic material is achieved through entry of the entire bacterium into target cells.