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Introduction to Picornavirus
Picornaviruses are a family of small, non-enveloped, single-stranded RNA viruses. They are among the most common viruses on Earth, causing a wide range of diseases in humans and other animals. Picornaviruses are typically less than 30 nm in diameter and have a genome of approximately 7,500 nucleotides.
Picornaviruses are highly infectious and can be transmitted through contact with infected secretions, such as saliva, mucus, or blood. They can also be spread through contact with contaminated surfaces, such as doorknobs, door handles, or countertops. Once inside the body, picornaviruses can infect a variety of cells, including cells in the respiratory system, the gastrointestinal system, and the central nervous system.
Most picornaviruses are relatively harmless and cause only mild, self-limited infections. However, a few picornaviruses, such as polio and hepatitis A, can cause serious, life-threatening diseases. There is currently no vaccine or treatment available for most picornavirus infections.
Picornavirus Classification
Picornaviruses are a family of small, non-enveloped viruses that are classified as positive-sense, single-stranded RNA viruses. They are typically about 30 nm in diameter and have a genome of 7-8 kilobases.
Picornaviruses are highly diverse and include viruses that cause a range of diseases in humans, including common colds, polio, and foot-and-mouth disease. They are also responsible for a significant number of deaths each year, particularly in developing countries.
The genome of a picornavirus is composed of a single piece of positive-sense, single-stranded RNA. This RNA is capped and polyadenylated, and encodes a single protein. The virus uses its own RNA polymerase to replicate, and does not require a host cell for replication.
Picornaviruses are relatively resistant to environmental stresses and can survive for long periods outside of a host cell. They are also relatively easy to manipulate and are often used as a model system for studying viral replication.
Characteristics of Picornavirus
Picornaviruses are small (18-30 nm in diameter), single-stranded, positive-sense RNA viruses. They are non-enveloped and have a icosahedral capsid. Picornaviruses are highly resistant to environmental stress and are capable of withstanding freezing, high temperature, dehydration, and radiation. They are also resistant to many disinfectants.
Structure of Picornavirus
Picornaviruses are a family of small, single-stranded, positive-sense RNA viruses. They are non-enveloped and have a helical nucleocapsid. The genome is about 7.5 kb in length and encodes for a single polyprotein. This polyprotein is cleaved by cellular proteases into structural and non-structural proteins. Picornaviruses are highly infectious and can cause a wide range of diseases, from the common cold to polio.
The picornavirus genome is composed of a single, positive-sense RNA molecule. This RNA is about 7.5 kb in length and is capped and polyadenylated. The genome encodes for a single polyprotein. This polyprotein is cleaved by cellular proteases into structural and non-structural proteins.
The structural proteins include the viral capsid proteins, which form the helical nucleocapsid. The non-structural proteins include the RNA-dependent RNA polymerase (RdRp), which is responsible for replication of the virus genome, and the 2A protease, which is responsible for cleaving the polyprotein into functional proteins.
The capsid proteins are encoded by the 5′ end of the genome, while the RdRp and 2A protease are encoded by the 3′ end of the genome. This organization is conserved among all picornaviruses.
Picornaviruses are highly infectious and can cause a wide range of diseases, from the common cold to polio. The mechanisms by which they cause disease are not fully understood, but it is believed that they interfere with the normal function of the host cell, either by disrupting the cell’s metabolism or by interfering with its ability to replicate DNA.
Picornaviruses are currently being studied as potential vectors for gene therapy. Their small genome and easy-to-edit RNA make them ideal for this purpose.
