26 December 2020 11:17
Viruses are everywhere and there the most abundant biological
entity on our planet. Also viruses infect every living thing.
Human and many other living animals, plants transmit viral
infections between and to other organisms.
What is the Virome?
• The virome is the community of viruses present in the
environment - human/elsewhere.
• Part of the larger microbiome
• Approx. 1031 virus particles on earth
• Constantly exposed to viruses through the air we breathe,
our food, other humans, plants and animal.
• Viruses have potential to move between species
There are eukaryotic virome which infects eukaryotic cells.
Prokaryotic virome are bacteriophage which infects bacterial
cells. There are also Endogenous Viral Elements.
How do viruses affect us?
Acute Disease: Ebola virus, measles virus
Long-term infection: HIV, HSV
Oncogenesis: hepatitis C virus, Epstein Barr virus
Economic impact: Foot and mouth disease bluetongue
Around 20% of human cancer are caused by viruses.
Plant viruses - Economic effect
Tomato necrotic streak virus - they affect tomato plants and
causes their plant cell deaths.
Viruses can be good as well as bad:
Bacteriophages: alternative to antibiotics
Oncolytic viruses: viruses that are engineered to infect and kill
tumour cells specifically.
For example T-Vec which is a modified herpes simplex virus
engineered to kill malignant melanoma. This virus can't replicate
in non-tumour cells.
Gene therapy vectors: Adenovirus in cystic fibrosis
Attenuated virus is engineered to express a functional version of
a gene that is defective in individuals with cystic fibrosis. This is a
gene for ion channels and CF particularly affect their lungs and
the ability of the lung to clear mucus.
Adenovirus is delivered through the respiratory route to deliver
a functioning gene into the cells within the lungs to make a
functioning protein.
Biological control: the control of a pest by the deliberate
introduction of a pathogen.
How baculoviruses are used as insecticides?
The baculovirus infects the insects and eventually kill them.
Leaves are sprayed with occlusion bodies, ingestion of occluded
viruses by the larvae. Dissolving of protein capsule in the
midgut, releasing of virions. Virions then infect the larvae
Global virome Page 1