Morphologic Changes of the Cells Infected with Rubella Virus

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.

RSV belongs to the paramyxovirus family of viruses. The virion encompasses a helical nucleocapsid packaged in a lipoprotein envelope attained from the host cell plasma membrane during budding. The external surface of the envelope contains a periphery of surface spikes.

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 introductory stages of the rash the small bumps are filled with a clear fluid and are known as vesicles, but as the virus progresses the vesicles become hard and scab over. The fluid inside the vesicles turns into puss and the large bumps then

First characterized as a mild sickness characterized by adenopathy, a rash, and hardly a fever, George Maton did not think much of the disease in 1814. However, later on, a scientist by the name of Veale gave it the name of rubella in 1866. Rubella (German Measles) attracted hardly any attention before 1942, when it was discovered by Norman Gregg that birth defects were being linked with maternal rubella in the first trimester. It was until 1962 that the full gravity of rubella embryopathy remained a mystery. In that year, two different groups by the names of Neva and Weller; and Parkman, Buescher, and Artenstein; isolated and clarified rubella in a single tissue culture. (1) Utilizing the newly developed tools of the virus laboratory, several

In order to test the rate of phagocytosis in tetrahymena, the tetrahymena need to ingest particles that are visible under a light microscope. The substance used in this experiment was India ink. India ink is deep black colored ink containing dispersed carbon particles. The trethymena treat the India ink as if it were food and ingest it. There were three concentrations of India ink that were fed to the eukaryotes The percent’s that were used are: 1%, 5% and 10% of India ink. After certain time intervals, the tetrahymena were fixed with a compound called 3% paraformaldehyde (PFA).On the first day six different mixtures of tetrahymena and ink concentrations were made to test which conditions would express the best rate of phagocytosis. The well fed tetrahymena were fed with 1% India ink, the another group was fed 5% India ink, the last group was fed 10% India ink. Then the starved tetrahymena were fed in the same manner as the well-fed tetrahymena. After adding the ink to the microcentrifuge, we prepared a slide for each mixture at the following time intervals 2 minutes, 5 minutes, 10 minutes, 20

RSV is caused by TLR3 activation. It initiates infections by binding to a cellular receptor and then the viral envelope fuses with the plasma membrane. The virus attaches the cell through the main protein, the G protein and fuses with the plasma membrane of the host cell through the F protein. After penetration, the nucleocapsid of the virus is released into the cytoplasm where replication occurs (3). The viral RNA is like a template for mRNA (3). The mRNA’s job is to translate the viral proteins and complementary RNA serves as a template for virion RNA

Our project revolved around two major ideas, the first idea that detected the expression of the Hemagglutinin glycoprotein of Measles virus (MV-H) on the surface of helper virus (Vesicular Stomatitis Virus) in our tissue culture. The second idea that identified the effect of Axl antibodies on the penetration processes of VSV-ΔG-MV-H virus The manner of this project represented in three major stages, the first stage that generated the VSV-ΔG-MV-H pseudovirion. This stage required to remove the VSV G glycoprotein gene from VSV and replace with gene for the green fluorescent in helper virus, however, this process was more complex so we skipped this step. The next step that was extraction the plasmid from the bacteria by following a specific protocol and then started working with PEI Transfection.

Some viruses also have an outer bag of lipo-protein called an envelope. After a virus attaches to a living cell, it either enters the cell to release the genetic information, or, the virus injects the information through the cells outer lining. Thus changing the cells natural functions and forcing the cell to spend its energy to create copies of the virus. The cell will go on making copies of the virus until the cell is used up and dies. The virus then leaves the dead cell and invades a nearby cell and the process starts all over. There are five types of human herpes virus: Varicella zoster which causes chickenpox, Epstein Barr virus which causes infectious mononucleosis, cytomegalovirus which can cause cytomegalic inclusion disease in infants, and herpes simplex viruses 1 and 2.

2) Almeida, J. D., Howatson, A. F., & Williams, M. G. Morphology of varicella (chicken pox) virus. Virology;1962,16(3), 353-355.

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

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

Herpesviruses may cause direct cytopathic effects on certain cells (fibroblasts, keratinocytes, endothelial cells, inflammatory cells such as polymorphonuclear leukocytes, lymphocytes, macrophages, and possibly bone cells). These changes may lead to a reduction in the number of these cells and so affect the cells ability to repair itself.

Cytogenic analysis – Microscopic examination of lymphocytes to look for structural changes or changes in number of chromosomes.

Cells were infected with the lentivirus, and they were selected by puromycin, finally there different cell clones were picked.1