Viruses are genetic elements enclosed in protein. Although some consider them to be non-living, viruses are important biological entities because they have the capability of producing disease (Raven, 2010). One of the most common viruses in humans is the Epstein- Barr virus or abbreviated (EBV). Throughout this essay, the biology of the Epstein-Barr virus will be examined by discussing characteristics that are associated with this virus such as the process of infection and entry, viral replication, and consequences to the host cell.
Epstein-Barr virus, which is also known as Human herpes virus (HHV-4), is an important virus because it infects a large portion of humans. (Odumade, 2011). Although most people become infected with the Epstein-Barr throughout some time in their life, it is often asymptomatic because it can exist in its latent phase. When people do show symptoms it is often due to infectious mononucleosis which is the disease that the Epstein- Barr virus can cause. The Epstein–Barr virus is named after Michael Anthony Epstein, a microbiologist at the University of Bristol, and Yvonne Barr a graduate from the University of London. Together they discovered and documented the virus (Wikipedia, 2014).
The DNA of the Epstein-Barr virus is a double helix that is wrapped in a protein capsid. The capsid is surrounded by an envelope made from lipids, which it takes from the host cell’s plasma membrane. The entire virus is approximately 120 nm to 180 nm in diameter, while the DNA, which contains all the genetic information of the virus, is about 192,000 base pairs long (Wikipedia, 2014). The viral envelope contains glycoproteins, which are essential to infection of the host cell (Odumade, 2011). Many believe that infection initi...
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...e, 2011). Instead, the circular genome can be found in the nucleus of the cell as an episome, where it is copied by the DNA polymerase of the host cell (Odumade, 2011). While in latency, only a partial genetic expression of EBV is occurring in order to keep it maintained. When the host cell is attacked by the EBV, an immune response is triggered during primary infection which controls infection, but does not eliminate it, so the virus ends up being present for the lifetime of the infected individual (Odumade, 2011).
The major factors involved in moving EBV through a membrane, how the virus replicates and how this virus affects the host cell have been identified. Although there is still much to be learned, what we know already provides insight into how this virus works and we can use different virus proteins to operate virus tropism and influence virus transferring.
In the early 1980’s, reports were appearing in California and New York of a small number of men who appeared to have rare forms of cancer and pneumonia (Blumberg). The men were young and in very good health (Blumberg). These men were alike because they were homosexual (Blumberg). They had a disease known as AIDS, which is caused by HIV (Blumberg). The virus slowly attacks the immune system which makes the human body more prone to infections (Blumberg). They did not know what the disease was for a while (Blumberg). It was believed to be “gay-related” because homosexuals were many of the first reported cases (Blumberg). That belief was abolished when scientist found out that heterosexuals could be infected too (Blumberg).
Carl Zimmer the guest speaker of this broadcast states that in 1981 doctors described for the first time a new disease, a new syndrome which affected mostly homosexual men. The young men in Los Angeles were dying and the number of cases was growing faster and faster. The number of deaths was increasing from eighty to six hundred and twenty five in just the first few months. After the first few cases in LA, AIDS was declared to be one of the deadliest pandemics the world had ever seen after the plague in the Middle Ages.
As a researcher, his main goal was to find a cure for cancer. The first discovery was made in 1952, in the developing field of virology. Virology is the study of viruses and how they behave. To develop the vaccines for the viruses, researchers infected the HeLa cells with many types of infections, such as measles, mumps, and the infamous poliomyelitis virus, also known as Polio. According to the Centers for Disease Control and Prevention (CDC), whose mission is to save lives and protect people’s health, Polio is a "crippling and potentially deadly infectious disease caused by a virus that spreads from person to person, invading the brain and spinal cord and causing paralysis" (Freeman).
Chester M. Southam, MD, was an American virologist who worked on curing cancer. “Studies had shown that a pathogen called the Russian spring-summer encephalitis virus could eradicate tumors in mice. Because that virus was considered too dangerous for people, Southam searched for something milder, settling on the newly discovered West Nile virus.” He had already spent some time in Africa injecting an assortment of viruses including mumps, dengue, West Nile, and Semliki Forest virus in severely ill cancer patients. The West Nile Virus usually
Like other negative-stranded RNA viruses, the G protein of rabies virus binds to the host cell membranes and penetrates into the host cytoplasm by pinocytosis. The virions are composed of cytoplasmic vesicles, fuse to cytoplasmic membrane and release RNP into the cytoplasm. The core starts primary transcription of the five complementary monocistronic messenger RNAs by using the virion-associated RNA-dependent RNA polymerase. Each mRNA is translated to an individual viral protein. After synthesis and replication of the genomic RNA, the full length, positive-stranded RNA is completed and becomes the template for the next negative-stranded RNA. In the assembly process, the N-P-L complex encapsulates negative-stranded genomic RNA to be made up of RNP core and the M protein consists of a capsule or matrix that su...
James Parkinson. It’s not certain how long the disease has existed but its probably been around
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.
West Nile Virus has emerged in recent years throughout the temporate zones of Europe and North America. Causing a variety of conditions in its hosts, the most serious manifestation of WN virus infection is fatal encephalitis (inflammation of the brain) in humans and horses, and many birds.
The influenza virus is an enveloped virus that contains a genome of eight genes that define what the virus is. Everything begins when the virus enters the airways. Here, influenza viruses specifically attach to the surface of epithelial cells. The viral membrane envelope contains the neuraminidase (NA) protein, which is important for the efficient release of newly produced viruses. It also contains the matrix 2 (M2) ion channel that promotes viral structural changes during cellular entry as well as the influenza hemagglutinin (HA) protein, the key player for viral internalization, which facilitates viral binding to sialic acid decorated receptors on host cells, causing adsorption to the host cell (Samji, p. 3). Barry compares the HA proteins to little spikes and the NA proteins to tiny trees that both protrude all around the surface of the virus (p. 103). When the HA protein spikes come into contact with the sialic acid molecules, both structures bind to one another. Once this binding holds the virus and host cell together, the virus has achieved its first task of adsorption. Next, the virus particles are internalized into endosomes by clathrin mediated endocytosis. The pH of the endosomes drops tr...
“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 ...
The length of the virus structure is of about 180 nm with a cross-sectional diameter of about 75 nm. Like a bullet, one end of the virus is rounded and the other end is planar or concave. The genome encodes 5-proteins: nucleoprotein (N), phosphoprotein (P), matrix protein (M), glycoprotein (G), and polymerase (L). The two major structural components of viruses like rabies that fall under the rhabdoviruses family are: a helical ribonucleoprotein core (RNP) and a surrounding envelope. Rabies is an RNA virus.
Hepatitis B, an infectious disease caused by the Hepatitis B virus (HBV, a DNA virus), was formerly called serum hepatitis, inoculation hepatitis and post-transfusion hepatitis. Infection with HBV may result in acute, fulminant or chronic hepatitis, sometimes even resulting in a chronic asymptomatic carrier state, apart from hepatocellular carcinoma and liver cirrhosis (Davis 179). The disease is transmitted when an individual comes in contact with infected blood or objects. It may also be transferred from an infected mother to her infant either during or after birth (Zuckerman et al. 211). Transmission may also occur by accidental inoculation from infected needles and hospital equipment, intravenous drug abuse, body piercing, tattooing, and mouth-mouth kissing (Zuckerman et al. 210). The risk of Hepatitis B is particularly high in individuals with multiple sex partners, and in homosexuals. The HBV virus occurs in morphologically different forms in the serum of infected individuals. HBV infection has an incubation period of about 75 days. Systemic symptoms of the disease include fatigue, fever, dyspepsia, arthralgia, malaise, and rash, while local symptoms include hepatomegaly, jaundice, dark urine, and pale stools (Davis 179; Zuckerman et al. 210).
Once you have the virus, the virus remains in a latent state within the nerve cell bodies in ganglion neurons and can reactivate at any future time. The reactivation frequency and severity depends on immunodeficiency status and stress levels. (Klein, 2016)
Infectious mononucleosis (colloquially known as mono) is frequently called the kissing disease. The virus that causes mono is called Epstein-Barr virus (EBV), which is one of the multiple human herpes viruses that are carried asymptomatically by most people. Primary infection is particularly usual in childhood and establishes a lifelong carrier state where the virus remains latent. The EBV replicates frequently in the oropharyngeal epithelial cells and circulating B-lymphocytes, since they are the principal targets of the virus.
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...