!!Rabies Virus
You are probably familiar with the image of a rabid animal foaming at the mouth, but most people don't know much about the virus or how it causes this disease. Rabies is caused by an infection spread through saliva. The saliva must come in contact with an open wound so it is usually spread through bites, though there have been reports of transmission through saliva contacting scrapes or mucous membranes like the mouth or nose. The virus can infect any mammal but typically is found in animals like bats, raccoons, foxes, and skunks. Domestic animals like cats and dogs can also be infected, which is why there are laws requiring them to be vaccinated against the virus.
!!!Disease Progression
If someone were to be infected, the
…show more content…
These viruses are bullet-shaped as can be seen in the electron micrograph image. [{Image src='vesicular_stomatitis_virus_vsv_em_18_lores.jpg' alt='Rhabdovirus Electron Micrograph'caption='Electron Micrograph of a Rhabdovirus'}]
The outside of the virus is an envelope coated in the viral glycoprotein( __G__). Inside the virus, the matrix protein (__M__ ) provides structure to the viral envelope. The viruses genome is single-stranded RNA. This is coated in many copies of the nucleocapsid protein (__N__). The RNA and the N protein together form the ribonucleoprotein core (RNP). The RNP is like a long strand which wraps around the inside of the virus, binding to M, forming a spiral. The other two protein, a polymerase (__L__) and a phosphoprotein (__P__), are also inside the virus.
The G protein binds to cells and starts the infection. The virus __uncoats__ inside the cell, which means that the RNP is released into the cytoplasm where viral replication take place. The first step is for the virus to make its proteins. The viral RNA is used as a template for the L protein to transcribe messenger RNAs (mRNAs). These mRNAs tell the cell's ribosomes to make viral proteins instead of the cell's proteins. Once enough viral proteins are made, the L protein starts to make new copies of the viral genome. This RNA is bound by new copies of the L, P, and N protein forming new RNPs. These are covered with M protein and then gain an envelope with the G protein as it leaves the cell forming a new infectious
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.
The SH (small hydrophobic) protein, matrix protein (M), and the M2 protein are envelope-associated proteins that are not involved in viral attachment or syncytium formation (3). Other proteins such as the nucleoprotein (N), phosphoprotein (P), and the large nucleoprotein (L) are in the nucleocapsid. NS-1 and NS-2 are non-structure protein that is only found in the infected cells but not present in virions (3).
Step 1: How will you identify the “vital” cellular protein that the virus targets for degradation? (Hint: think proteomics). (3 pts.)
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.
* 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.
A virus is a capsule containing genetic material, even smaller than bacteria. The main task of virus is to reproduce. However, viruses need a suitable host to
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.
When we hear the word virus, we usually think of something that makes us sick. A virus is an ultramicroscopic infectious organism that, having no independent metabolic activity, can replicate only within a cell of another host organism. A virus consists of a core of nucleic acid, either RNA or DNA, surrounded by a coating of antigenic protein and sometimes a lipid layer surrounds it as well. The viral genome provides the genetic code for replication, and the host cell provides the necessary energy and raw materials. To fight viruses, we use vaccines. While some may infect a broad range, other viruses can only infect certain kinds of cells. Vaccines are made of inactive, dead or weakened virus cells or protein antigens that can no longer infect
Once tightly bound the virus is endocytosed via coated vesicles. The virus is transported into late endosomes which acidify their content and hence induce conformational rearrangement of HA exposing the fusiogenic peptide sequence. The loop region of the HA becomes a coiled coil that mediates membrane fusion. The release of viral genome into the cytoplasm also requires protons that are pumped from the acidic endosome into the virion interior via the matrix protein M2 that acts as a proton channel. Viral RNA dissociates from M1 and is then imported in an ATP-dependent manner into the nucleus for transcription and translation. In humans, the replication of the influenza virus is usually restricted to the airways epithelial cells due to the limited expression of a serine protease, produced by nonciliated bronchial epithelial cells and which cleaves the HA precursor in HA1 and HA2 polypeptides, rendering the virions infectious. Replication and virions production occurs within hours after virus entry. The viral ribonucleoprotein (vRNP) complexes are released from the endosomes into the cytoplasm and subsequently transported to the nucleus, where replication and transcription take
Rabies is a infectious disease that is spread through animal bites. The saliva of the infected animal contains the virus. People get rabies from animals like wild dogs, wolves, foxes, bats, skunks. People most commonly get rabies from raccoons. Most people who get rabies live in Africa, Latin America, Asia, and India. There are about 59,000 deaths from rabies each year. Over 90% of the rabies death are from Africa, Asia, and the Middle East; where there are widespread canine rabies.
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 HIV-1 virion is approximately 120 nm in diameter, roughly spherical, and is composed of two copies of a single stranded positive sense RNA enclosed by a capsid (24). The HIV-1 genome is less than 10 kb and encodes for more than nine different gene products. It encodes for 3 major structural protein genes: gag (group-specific antigen), pol (DNA polymerase), and env (Envelope), which code for major structural proteins and essential enzymes. Gag generates the mature Gag protein matrix (MA or p17), capsid (CA or p24), nucleocapsid (NC or p7), and p6, which encompass proteins for the basic infrastructure of the virus such as the inner core of the viral particle (25). Pol encodes for reverse transcriptase (RT), which enables the virus to reproduce, integrase (IN), which is necessary to integrate the viral double stranded DNA into the host genome, RNAse H, and HIV protease, which are all encapsulated in the core of the inner particle formed by the viral capsid protein p24 (25). Env encodes for glycoproteins of the outer membrane such as outer gp120 (which enables the virus to attach and fuse to cells of the host), and transmembrane gp41 that anchors the glycoprotein complex to the surface of the virion (25). Between the core and the envelope is the HIV matrix proteins which are composed of the viral protein p17 (23). HIV-1 also encodes for proteins with important regulatory elements (tat (Trans-Activator of Transcription) and rev
Rabies is a highly infectious viral disease that can easily ruin and eventually end the lives of both humans and animals alike. Rabies comes in two forms for animals. It comes in the form of paralytic rabies, which is the kind that puts you in paralysis right from the beginning, skipping the symptoms of agitation and excitability. Rabies also appears in the form of furious rabies, which is completely different in the way that it makes the victim restless, vicious and agitated. When humans get rabies, their symptoms start out with simple headaches and fevers and later progresses to terrible things such as becoming hydrophobic because of painful throat spasms and paralysis. A definite diagnosis of rabies needs lab analysis of
Because rabies is transmitted through saliva, the disease is usually brought about into the body by a bite of an animal already infected with the lyssa virus (rabies). Rabies then deposits itself into the tissue of the host (person/animal who has the virus in them), infecting the host and later multiplying. From there, the virus travels from the nerves to the muscles, then to the brain and spinal cord (Easmon paragraphs 8-9). At this point, the virus is multiplying rapidly and soon the brain is extremely affected, which causes it to malfunction and the part of the brain that controls breathing shuts down (Buncombe paragraph 8).