Virus

                     

                 VIRUS                      

• The word virus comes from the Greek, meaning that venom toxins.
• Generally viruses are genetic elements that contain any of the nucleic acid, namely the deoxyribonucleic acid (DNA) or ribonucleic acid (RNA)
• The virus can be in two different conditions, ie intracellularly (in the host's body) and extracellular (outside the host's body).
• Virus particles when outside the host known as the virion

1. Viruses may act as agents of disease

•    As an agent of the disease, the virus enters the cell and lead to harmful changes to cells, which eventually can damage or even cause death.
•    As heir to the nature of the agent, the virus enters the cell and remain in the cells permanently.

A. Characteristics Virus

• The shape is 28-200 nm
• T-shaped, rod, ball, needle, and others.
• Is a non-cellular organisms (no protoplasm, cell membranes and no organelles).
• Parasitic obligas (life is very dependent on the host)
• Just having a core material in the form of DNA or RNA
• His body was protected by kapsaid
• Kapsaid unit composed of a protein called kapsomer
• Can be crystallized
• Can multiply (proliferate) in cells or live tissue
• Can pass through the filter bacteria
  
  

B. Virus classification.

Based on the type of hosts infected:

1. Plant viruses, for example, is Tobacco Mosaic Virus (TMV), which is a kind of virus that attacks the leaves of tobacco and Potato Yellow Dwarf Virus, the virus that attacks the yellow potato.
2. Animal viruses, for example, is Rhabdovirus that cause rabies in dogs and New Castle Disease (NCD) that causes the disease of poultry tetelopada
3. Human viruses, for example, is a polio virus, influenza, hepatitis, AIDS and SARS
4. Virus bacteria, for example, is Bacteriophage T4

Based on the type of nucleic acid contained by the virus:

1. RNA viruses, for example, is the influenza virus, the HIV virus and corona virus (SARS)
2. DNA viruses, for example, is a poxvirus, herpes virus, and adenovirus.

C. Bacteriophage T4

a. Cycle Stages Litik

• In the lytic cycle, the virus to penetrate the host and multiplies within inag, then outside the host. Host cells through lysis (rupture)   
• Lytic cycle stages as follows:
  - Adsorption (attachment) of the particles (virions) on a suitable host cell.
  - Penetration (injection) sour nekleat virus into the host cell
  - The initial stage of viral nucleic acid replication. In this event the host cell biosynthetic machinery is taken over to start a viral nucleic acid synthesis. Specific enzymes the virus began to be produced in this phase, called the eclipse phase.
  - Replication of the viral nucleic acid.
  - The synthesis of viral coat protein subunit.
  - Assembly of nucleic acid and protein subunits and membrane components on membranous virus into virus particles
  - The release of mature virus particles from the cell (lysis)

b. Lysogenic cycle stages

• In the lysogenic cycle, the virus nucleic acid inserts in linang nucleic acids, viral propagation does not occur in the host, and the host cell does not undergo lysis
• Lysogenic cycle stages as follows:
  - Adsorption (attachment) of virus particles (virions) on a suitable host cell
  - Penetration (Injection) viral nucleic acid into host cells
  - Viral nucleic acid inserts / melt at iang nucleic acid forming profage
  - When bacteria-division, will participate profage doubled and beyond
  - Once profage the bacteria out of the body and into the lytic cycle

D. Some diseases caused by viruses

a. Diseases Transmitted Through the Air

1. Cold
   Colds are a common disease that affects children and adults. The disease is caused by a virus rhinovirus (single-chain RNA viruses)
   Suffered symptoms include fatigue and the number of mucus from the nose
2. Influenza
   Influenza is caused by Orthomyxovirus (viral RNA)
   This virus is transmitted through the air, especially from splashes when coughing or sneezing
   Suffered symptoms include mild fever of 3-7 days, cold, lethargy, stiff, and headache
3. Measles
   Measles is a disease that usually Affects children. The cause of measles is a paramyxovirus that goes through the nose and throat from the air and quickly intervening spread throughout the body. The disease is marked by the symptoms of runny nose, red eyes, cough, and heat. Complications from measles are frequent ear infections, pneumonia, and measles enchephalomielitis (rare)
4. Mumps
   Mumps is caused by a paramyxovirus with a different type of paramyxovirus causes measles. The disease is characterized by swelling of the salivary glands that cause swelling of the jaw and neck
5. SARS (Severe Acute Respiratory Syndrome)
   SARS is a disease that is transmitted through the air as a result of splashing sputum or sneezing of people who suffer from the disease. The disease attacks the respiratory tract, especially the lungs. Microbiologists discovered the virus that causes SARS from paramyxoviridae group called corona virus.

• Currently, there is some flu-like illness, the bird flu (Avian influenza) is caused by the H5N1 virus and the swine flu caused by the H1N1 virus. Both types of the virus have a high level of virulence and off (H = hemagglutinin, N = neuraminidase)

b. Sexually Transmitted Diseases

1. Herpes
   The disease is caused by the herpes virus. Transmission is through direct contact with wounds caused by the virus. Herpes simplex viruses can cause sores around the mouth and also can cause genital tract infection
2. AIDS (Acquired Immune Deficiency Syndrome)
   AIDS is caused by HIV (Human Immucunodeficiency Virus) which is a group restovirus (single-chain RNA viruses). This virus attacks the T lymphocytes that normally function as the immune system becomes impaired. This will cause infections that lead to death in patients.

c. Diseases Transmitted Through Animals

1. Rabies
   Rabies is caused by a virus from the group rhabdovirus (single-chain RNA viruses). The virus can be transmitted to humans through the bite of an animal with rabies pets such as cats, dogs, and monkeys. The rabies virus attacks the central nervous system of warm-blooded animals and generally lead to death if untreated.

d. Diseases Transmitted Through Food

1. Hepatitis
   Hepatitis is caused by the hepatitis virus. The disease is transmitted through water, food, saliva, or feces of contaminated milk. The virus can cause hepatitis A, B, C, D and E. The infection caused by the Hepatitis A can lead to liver problems if the infection is chronic, while Hipetitis B can lead to liver problems more acute than with Hepatitis A and can cause death

A few that I share information about the virus. Hopefully this information can be useful. Thanks. :)