Research Paper On Orthobunyavirus

How does viral replication work when compared to the normal process of replication? [8 pts]

* Flaviviruses: share a common size (40-60nm), symmetry (enveloped, icosahedral nucleocapsid), nucleic acid (positive-sense, single stranded RNA approximately 10,000-11,000 bases), and appearance in the electron microscope. Therefore, images of West Nile virus are representative for this group of viruses.

Viruses are microscopic particles that invade and take over both eukaryotic and prokaryotic cells. They consist of two structures, which are the nucleic acid and capsid. The nucleic acid contains all genetic material in the form of DNA or RNA, and is enclosed in the capsid, which is the protein coating that helps the virus attach to and penetrate the host cell. In some cases, certain viruses have a membrane surrounding the capsid, called an envelope. This structure allows viruses to become more stealthy and protected. There are two cycles in which a virus can go into: lytic and lysogenic. The lytic cycle consists of the virus attaching to a cell, injecting its DNA, and creating more viruses, which proceed to destroy the host. On the other hand, the lysogenic cycle includes the virus attaching to the cell, injecting its DNA, which combines with the cell’s DNA in order for it to become provirus. Then, the provirus DNA may eventually switch to the lytic cycle and destroy the host.

The virus fuses with the cell’s plasma membrane. The capsid proteins are removed, releasing the viral proteins and RNA. Reverse transcriptase catalyzes the synthesis of a DNA strand complementary to the viral RNA. Reverse transcriptase catalyzes the synthesis of a second DNA strand complementary to the first. The double-stranded DNA is incorporated as a provirus into the cell’s DNA. Proviral genes are transcribed into RNA molecules, which serve as genomes for the next viral generation and as mRNAs for translation into viral proteins. The viral proteins include capsid proteins and reverse transcriptase (made in the cytosol) and envelope glycoproteins (made in the ER). Vesicles transport the glycoproteins from the ER to the cell’s plasma membrane. Capsids are assembled around viral genomes and reverse transcriptase molecules. New viruses bud off from the host cell.

In the article, we learn the Cache Valley virus is spreading quickly through mosquitos. In this unit we learned that viruses with RNA in their nucleic acid reproduce a lot faster than viruses that have DNA in their nucleic acid, therefore the Cache Valley virus probably has RNA in its nucleic acid. Throughout the unit we learned viruses can spread through many types of mediums such

With the continuous research of these swarms we will better understand the relationship these viruses share with their

There is still a great deal of information to learn from the study of viruses and the continued exploration of the viral genome is crucial in understanding how viruses communicate, transmit from host to host and evade immune responses. The ever-change nature of the viral genome has shown us that the most dangerous viral infections of today may be undermined by newer and more effective viruses, resulting in catastrophic outcomes. Through the study of viruses, it is the hope of the scientific community to be ahead of the viral curve, preventing infections before they even

The norovirus is small and round. It is only 27-35 nm in diameter. The virus contains a single- stranded RNA genome. Noroviruses are divided into five genogroups, G1- G5. Of these five genogroups, only G1, G2, and G4 are known to infect humans. G2 is the most common in adult cases of gastroenteritis. 1 “Noroviruses are not enveloped and contain an outer protein capsid encapsulating an RNA genome.”2

The influenza virus thrives because of its unique characteristics that allow it frequently change and undergo evolution. The influenza virus has a segmented genome meaning that each section of RNA is copied separately allowing reassortment to play a major role in the evolution of the influenza virus. When two different strands of the virus attack the same cell, both strands of RNA are copied in the nucleus. These copies then move to the cytoplasm where new viruses are compiled. Each new virus needs all eight of its genomes which can come from a copy of either of the original infecting viruses. The new virus would then have a mixture of RNA from each originating virus causing it to be different from both (Rahnama, L, et al., 2013). Reassortment causes new strains of viruses

Viruses can replicate themselves but only within a host cell in which they hijack as they do not own any translational machinery, so it is unable to create new RNA or DNA fragments or create a new set of virions5. In the first stages of viral replication the virus will attach itself onto a host cell via the glycoprotein spikes which eject off the capsid – this is called adorption6. The virion will then transfer its genomic material whether its RNA or DNA into the host cell via penetration of plasma membranes and this occurs through receptors binding to receptor sites and activating a chain of reactions6,7. The virus will the inject its own genomic material into the host cell which causes the host cell to use its replication techniques to replicate the foreign genome meaning its expressed by the host cell – hijacking the cell6. The genomic material that is now in the cell will be replicated as the cell is infected and will express these new characteristics of the virus instead of being able to carry out its own job. The newly produced proteins and enzymes will now mature within the host cell and group together to form new virions and viruses. After these are fully matured the enzymes produced will catalyse the cell membrane of cells and allows the newly produced viruses to be released into the extracellular environment6. This process of replication is also the way in which viruses adapt to their environments another component of being classed ‘alive’ because they

West Nile virus is found on every continent except Antarctic. “West Nile virus was first isolated in Uganda in 1937 from the blood of a native Ugandan woman, and until the end of the 20th century was considered a cause of viral encephalitis limited only in Africa and Asia.” It did not become a global concern until 1999 when it was introduced to North America.in New York City Hundreds to thousands of cases before 1996 were mostly in rural populations and were rarely severe. The primary host of West Nile virus is avian species, birds. Other infected organisms can include humans and other mammals with horses being the most common. The main way the disease is transmitted is through a bite of infected mosquitoes, specifically Culex species. The virus may also be transmitted between individuals through blood transfusions, organ transplantations, and although rare it can be transmitted from the mother to newborns either through intrauterine route or breast-feedings. West Nile virus can be dived into seven genetic lineage strains. “Lineage one is the most widespread, containing isolate found in Europe, North America, Asia, Africa, and Australia… Lineage two strains are mainly distributed in Sub-Saharan Africa and Madagascar, but in the last decade they have been introduced in Europe. Lineage three contains a strain

The human herpes virus has a diameter of 150 nm. The DNA genome in the core is surrounded by an icosadeltahedral capsid. The capsid contains 162 capsomeres and it is enclosed with an envelope. Several glycoproteins are encoded into the envelope. Between the envelope and the capsid there is a space known as tegument which contains viral proteins and enzymes and it helps in replication

Influenza, more commonly known as the ‘flu’, is a chameleon like infectious disease, that presents itself with varying characteristics from year to year, due to the wavering identity of the strain. “Like HIV, influenza is an RNA virus, constantly changing its appearance and adept at eluding recognition by the human immune system” (Schneider, 2014). From its inception of 1918, influenza claims an average of 250,000 to 500,000 people worldwide, annually. Little is known of the virus’s origin however; recent studies examined pathology specimens belonging to deceased soldiers of 1918, revealing similarities with that of the avian flu virus (Schneider, 2014). Evidence has correlated a pattern of influenza strain elements, accompanied by consistent transmutation, that has established a paralleled relationship between that of animal reservoirs and Asia. It is believed that global transmission of the virus is carried via birds that consume food from the same sources that of pigs, consisting of contaminated feed and waterfowl. “Human and animal influenza viruses incubate in a pig’s digestive system, forming new genetic combinations” (Schneider, 2014). Asia occupies cohabitation of the two species that yield fertile breeding grounds for a virus to manifest, while posing a significant threat and concern to the heavily populated areas within close proximity.

This little package of mayhem consists of relatively few parts. A virus is simply a protein capsule called a capsid, sometimes surrounded by an envelope, containing a genome. The genome consists of nucleic acids arranged as DNA or less commonly, RNA. Dozens of variants of this fundamental arrangement exist with differences in the structure of the capsule and the arrangement of the genome. Small differences or changes in these components allow some viruses to continue to outmaneuver researchers, while millions of dollars are spent trying to understand and eliminate them.

The similarity between the poliovirus and already solved plant virus’s led to a better understanding of how the poliovirus can regenerate within a host. Although the virus was similar to other plant viruses. The poliovirus was covered with more elaborate loops that are the site of monoclonal antibody escape mutations (Hogle, Chow and 229: 1358-1365Filman, Science). Individual proteins of the virus particle are produced by proteolytic cleavages from a larger precursor, yet the amino and carboxy-termini produced by proteolysis are very distinct. By noting this, Hogle and his team were able to conclude that proteolysis was not just making a lot of proteins from one gene, it is also controlling the timing of assembly (Hogle, Chow and Filman, Science 229: 1358-1365).