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DEFECTIVE VIRUS. "From a virologic standpoint it is noninfectious material of no consequence, and from an immunologic standpoint it is the by-product of a viral mechanism to stay one step ahead of the cellular and humoral responses." https://lnkd.in/egPav5U View in LinkedIn

DOUBLE WHAMMY. "Viruses produce double-stranded RNA (dsRNA) during reproduction, which can trigger the silencing of viral RNA. RNA silencing can also be triggered by a sufficiently high expression of transgenes, a mechanism known as co-suppression or transgene induced silencing. The activation of transgene induced RNA silencing is directly linked to the activity of RNA directed RNA polymerase (RDR)." https://lnkd.in/e_PqVyJ View in LinkedIn

"DEFECTIVE VIRUSES, thought for decades to be essentially garbage unrelated to the transmission of normal viruses, now appear able to play an important role in the spread of disease." Few things in nature, it seems repeatedly, actually turn out to be garbage. https://lnkd.in/eAvD9w4 View in LinkedIn

NATURE's VITAL VACCINE. "RNA silencing protects the eukaryotic cell against viruses and transposons." https://lnkd.in/e_PqVyJ View in LinkedIn

"REPLICATIVE-DEFECTIVE viral mutant strains provide a new form of viral vaccine that combines some of the advantages of each of the two classic vaccine forms. Replication-defective mutant viruses are specifically defective for viral functions that are essential for viral genome replication and assembly of progeny virus particles." https://lnkd.in/eCpd2iP View in LinkedIn

"RNA SILENCING is a novel gene regulatory mechanism that limits the transcript level by either suppressing transcription (transcriptional gene silencing [TGS]) or by activating a sequence-specific RNA degradation process (posttranscriptional gene silencing [PTGS]/RNA interference [RNAi])." https://lnkd.in/eity6gi View in LinkedIn

DEFECTIVE INTERFERING (DI) "genomes are synthesized by nearly all known viruses and represent a vast natural reservoir of antivirals...during successive undiluted passages, the yield of infectious virus cycled from high to low...non-infectious virus particles resulted from large (up to 90%) deletions in one or more of the eight viral genome segments. In the presence of these defective particles the production of infectious virus is severely diminished and this led to the designation of the mutants as defective interfering (DI) viruses." https://lnkd.in/egCZeY2 View in LinkedIn

A WRECK. "Many DI viruses contain deletions so extensive that they do not encode any functional protein. The deletions arise due to errors in replication in which the polymerase carrying out the replication process leaves the template nucleic acid, and either rejoins at a distant point on the same or another template or, in the case of some DI viruses with RNA genomes, switches from the template to copy back along the newly synthesised RNA." https://lnkd.in/egCZeY2 View in LinkedIn

UNIVERSAL. "The production of DI viruses has been demonstrated in almost every virus system studied." https://lnkd.in/egCZeY2 View in LinkedIn

HELPER VIRUS. "DI viruses are defective because the deleted genome lacks an essential gene required for replication. In order to replicate, DI viruses require assistance of the infectious virus from which they were derived, or a genetically compatible related virus, to provide the missing gene products. This is referred to as a helper virus. DI virus production is optimal in the presence of a large amount of helper virus but as the DI virus replicates it reduces the yield of infectious helper virus." https://lnkd.in/egCZeY2 View in LinkedIn