Viruses are obligatory intracellular parasites that require getting into a host cell to replicate and release new viral particles that will, in turn, infect other cells. To do this, they take advantage of host receptors and activate endogenous cellular responses that allow them to get through membranes and be delivered into their site of gene expression and replication (Marsh & Helenius, 2006). Different types of viruses have developed different cell entry strategies, depending on the target cells, the viral genome and the virion structure; in this case we will be looking at similarities and disparities that arise between the early phases of infection of an enveloped and a non-enveloped virus, taking Influenza A and Poliovirus respectively as examples.
Influenza A, as a member of the Orthomyxoviridae family, has a negative-sense, single-stranded, segmented genome and a host-derived lipid envelope. Influenza A is a pleomorphic virus that can be either spherical or filamentous (Rossman et al., 2012) and has 8 fragments which are incorporated into virions as viral ribonucleoprotein complexes or RNPs (Figure 1); the presence of a copy of each essential for the virion to be infective (Bouvier & Palese, 2008). Although Influenza is a RNA virus, it has the peculiarity of carrying out transcription and replication inside the host cell nucleus, allowing the RNPs to associate with the host RNA polymerase II to use the 5’ cap from nascent cellular mRNAs as primers, at the same time causing a reduction in host transcription, and letting the virus make use of host mRNA processing pathways and splicing (Hutchinson & Fodor, 2013; Palese & Shaw, 2007).
Poliovirus, the prototype member of the Picornaviridae family, is a non-enveloped virus wit...
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... in Influenza A this role is played by HA, a surface glycoprotein inserted in the lipid envelope (Skehel & Wiley, 2000), whereas Poliovirus has a cleft or canyon on its capsids outer surface that will recognise the cell receptor (Colston & Racaniello, 1994). The fact that Influenza A RNPs require a further step before the viral genome can be activated, and have to be transported into the nucleus after entry into the cytoplasm, is more a specific trait in Influenza virus than due to having an envelope (Palese & Shaw, 2007), but it does constitute another disparity between the two viruses. In conclusion, the two viruses follow similar receptor recognition and internalisation routes, but then diverge when they reach the stage in which penetration across the host cell membrane is triggered, the only similarity being the use of specific proteins to enable this step.
However due to globalization, import and export viruses is more easily transmitted. Over the past century the global community especially Asian has been affected with new strains of the influenza virus. The changes in the virus can occur in two ways “antigenic drift” which are gradual changes in the virus over time. This change produces new strains that the antibody may not recognize. “Antigenic shift” On the other is a sudden change in the influenza virus which ‘’ results in a new influenza A subtype or a virus with a hemagglutinin or a hemagglutinin and neuraminidase combination that has emerged from an animal population,” as seen with H5N1 virus. This change leaves people defenseless against this new virus. (CDC, 2013) Currently there is no vaccine to combat all strains therefore “Planning and preparedness for implementing mitigation strategies during a pandemic requires participation by all levels o...
Viruses are the simplest and tiniest of microbes, and are made up of proteins, nucleic acid, and lipids. The nucleic acids contain the genetic code that helps them grow and reproduce, but only once they find their way into a living organism. Viruses themselves are not considered living organisms because they don’t have cells, they don’t metabolize nutrients, produce and excrete wastes, and they can’t move around on their own. The remains of the nucleic acid then forms a covering, called the capsid. Once the capsid gets removed, viruses use the building materials of th...
The virus is primarily spherical shaped and roughly 200nm in size, surrounded by a host-cell derived membrane. Its genome is minus-sense single-stranded RNA 16-18 kb in length. It contains matrix protein inside the envelope, hemagglutinin and neuraminidase, fusion protein, nucleocapsid protein, and L and P proteins to form the RNA polymerase. The host-cell receptors on the outside are hemagglutinin and neuraminidase. The virus is allowed to enter the cell when the hemagglutinin/ neuraminidase glycoproteins fuse with the sialic acid on the surface of the host cell, and the capsid enters the cytoplasm. The infected cells express the fusion protein from the virus, and this links the host cells together to create syncitia.
Both 1984 and The Handmaid’s Tale are dystopian novels, however, these books are a lot more complex than mere portrayals of dystopia, it can be argued that they are explorations of dystopia rather than mere portrayals. In order to explore dystopia, many themes must be considered, such as; feminism, love and repression. Nonetheless, it is apparent that human characteristics are the driving point of the two novels, predominantly, the depiction of human resilience. In an imperfect world, it is important to have certain qualities which, if plentiful, it can mean success, whereas if it lacks, it can mean failure, this characteristic is resilience. The protagonists in each novel, Winston in 1984 and Offred in The Handmaid’s Tale face situations which leave them both in disarray, and both even consider suicide. The authors tentatively highlight human resilience, its limits and most importantly its strengths into the two novels.
Loo, Yueh-Ming and Michael Gale, Jr. “Influenza: Fatal Immunity and the 1918 Virus.” Nature 445 (2007): 267-268. 23 July. 2008 .
Kimball, Dr. John. A.S.A. “Influenza.” 8 Feb. 2007. Kimball’s Biology Page. 23 July 2007 http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/I/Influenza.html>.
At no time was a search for the cure for influenza more frantic than after the devastating effects of the pandemic of 1918. The pandemic killed somewhere between twenty and a hundred million people, making it twenty five times more deadly than the ordinary cough and sneeze flu. The symptoms of this flu were like something straight out of a horror movie: the victim’s facial complexion changed to a dark, brownish purple, the feet turned black, and they began to cough up blood. Eventually, death was caused, literally by drowning, when the victim’s lungs filled with their own blood. The first scientist to claim to solve the enigma of influenza was Dr. Friedrich Johann Pfeiffer. He isolated a bacterium he named Hemophilus influenzae from the respiratory tract of those who had the flu in the pandemic of 1890. He was believed to be correct in his discovery until the pandemic of 1918, when scientists searched the respiratory tracts of influenza victims and only sometimes found his bacterium. Robert E. Shope and his mentor Paul Lewis were the next to attempt to crack the code of influenza. They chose to study the disease in pigs, a controversial choice because many people believed that the swine influenza pigs were contracting was not the same as the human flu. The first experiment they ran was ba...
“This knowledge will help us design drugs that mimic the viral effects on these proteins to either activate a host’s immune response or shut it down,” said Dr. Michael Gale, associate ...
Scott Hightower’s poem “Father” could be very confusing to interpret. Throughout almost the entirety of the poem the speaker tries to define who his father is by comparing him to various things. As the poem begins the reader is provided with the information that the father “was” all of these things this things that he is being compared to. The constant use of the word “was” gets the reader to think ‘how come the speaker’s father is no longer comparable to these things?’ After the speaker reveals that his father is no longer around, he describes how his father impacted him. Details about the father as well as descriptions of the impacts the father has distraught on the speaker are all presented in metaphors. The repetitive pattern concerning the speaker’s father and the constant use of metaphors gives the reader a sense that the speaker possesses an obsessive trait. As the reader tries to interpret the seemingly endless amount of metaphors, sets of connotative image banks begin to develop in the reader’s mind. Major concepts that are expressed throughout the poem are ideas about what the speaker’s father was like, what he meant to the speaker, and how he influenced the speaker.
In order to decide whether or not the swine flu vaccine is completely necessary, one must first gain a better understanding of the topic. It is a scientifically known fact that the swine flu is a result of a virus. A virus is a capsule of genetic material that causes infection in the body. The infectious particles are made up of nucleic acid enclosed in a protein shell, called a capsid. It cannot be considered a living organism like the disease causing agent of bacteria, because it does not carry out all the characteristics of life. Specifically, it cannot reproduce on its own.
The swine influenza or swine flu is a respiratory disease in pigs that is caused by the type A influenza viruses. These viruses are referred to as swine flu viruses but scientifically the main virus is called the swine triple reassortant (tr) H1N1 influenza virus. When the viruses infect humans they are called variant viruses. This infection has been caused in humans mainly by the H1N1v virus in the United States. The H1N1 virus originates in animals due to improper conditions and the food they ingest. The virus stays in latency form, thus harmless to the respective animal. The longer the animals survive the more likely the virus is to develop and strengthen making it immune to vaccines. The virus reproduced through the lytic cycle. The virus injects its own nucleic acids into a host cell and then they form a circle in the center of the cell. Rather than copying its own nucleic acids, the cell will copy the viral acids. The copies of viral acids then organize themselves as viruses inside of the cell. The membrane will eventually split leaving the viruses free to infect other cells.
The Civil Procedure Rules recognised in Wales and England imposes a positive duty on the court to encourage parties to use an alternative dispute resolution (ADR) procedures if the court considers it appropriate, from the forgoing it could be inferred that achieving unbiased and objective dispute resolution is no longer the exclusive claim of the adversarial legal process as hitherto claimed by liberal societies. In addition, exact practices of adversarial legal system scarcely exist, since the daily life of court now involves routine departures from its original fundamental ideals. Nonetheless, growing evidence depict that mediated outcomes are more likely to be complied with than court decrees contrary to the position of pro adversarial advocates.
...ound in our bodies. The trick is that the virus “gets confused” and incorporates the fatal molecule into its growing RNA strands which leads to the prevention of RNA synthesis and thus the entire viral replication.
The DENV envelope protein E, which is found on the virus surface, has a role as a mediating factor in the initial attachment of the virus to the host cell. Further, several cellular proteins and carbohydrate molecules that act as attachment factors interacting with the viral envelope protein E have been identified. These factors allow the virus population to concentrate on the cell surface thus increasing their chance of access to their target cellular receptor(s). Some of these known molecules that interact with the vi...