Viruses & its structure & process of infection
VIRUS
Viruses in Latin term Venom or Poison. A virus is non cellular , smallest type of parasite, infectious agent which taken over the host cell surface in our body for the survival and multiply.Many different viruses are capable of infecting bacteria, plant, and animal cells and more than 400 viruses are infecting human according to the research. The virus which infect the human or animals are called as ZOONOSES.
The viruses responsible for the viral diseases such as influenza(flu), chicken pox, measles, viral pneumonia, rubella and small pox these are caused by transmitting of virus through the airways by infecting host cell by sneezing or coughing. Others viral diseases can be transmitted by means of Arthropods or Ticks leads to Colorado tick fever and Yellow fever.
Some viruses transmitted through the Physical contact for example AIDS, Cold sore, Genital herps and etc.
History
The viral diseases are the very afraid in the earliest centuries like COVID 19. One of these was SMALL POX caused by Variolla virus; the origin of this virus in not known but it origins in 3rd century in Egyptian mummies. It was the major outbreaks in the world. In 18 th century in Europe 400 00 peoples were died per year from the disease.Smallpox was estimated to have killed 300 million peoples around 20 th century.
And another recent outbreaks was FLU PANDEMIC (1918 to 19
in Spanish); it was the most severe pandemic in recent history caused by H1N1 virus from the bird avian. this virus predominantly affect 500 million peoples or one third of the population can affected with the viruses. The number of deaths was estimated that over 50 Million in the world.
Another virus was HIV is the Human Immunodeficiency Virus ;
it was originated from the Democratic Republic of Congo in 1920s.Globally it should be noted that around 33 million peoples were deaths by HIV/AIDS.
Lastly the SARS Coronavirus (2002 to 2004) (SARS CoV) (Severe Acute Respiratory Syndrome) was origin in 2002 produces the major devastating effects in the world. It should thought to be originated from the animals and uncertain animal reservoir and perhaps it could be transmits by the bats to the humans. Around 8000 cases of peoples were sick in the outbreak of SARS. Of these 774 peoples were died.
And Bioterrorism or Biowar is the method of fight where a disease is intentionally inflicted upon peoples in the country for the purpose of victory.
Structure of Viruses
Viruses are generally protein packages which transmitting the foreign unwanted nucleic acid into host cell of the human body. The viruses contains either RNA or DNA located in the nucleus and cytoplasm. Most of the RNA viruses contains Single Strand RNA (ssRNA) and DNA viruses contains Double Strand DNA(dsDNA) located in the nucleus of the virus.
The viral nucleic acid is protected within a protein coat called as Capsid made up of Protomers , the nucleic acid and capsid both are called as "Nucleocapsid" .In some viruses, the nucleocapsid may contains Viral enzymes which are important to its replication in the host cells. for example the Influenza virus may contains an enzyme RNA- dependent RNA- polymerase within its nucleocapsid for the purpose of replication of viruses.
The complete structure of virus is called as Virion (Nucleocapsid + Protein coat + Surrounding envelope )
Infection Process
I.Adsorption:
The Virion molecule binds to specific protein present in the host cell membrane and gets diffused into the cell membrane.
- Different viruses introduce their viral nucleic acid by different method; some of its penetrate or infect through the cell membrane and gets uncoated.
- Other viruses are entered into the cell membrane by Endocytosis (actively transporting viral protein into the host cells by means of engulfing it with its membrane) where the cell membrane wraps itself around the virion and pinched off to produce vesicle called as Endosomes and it causes delivery of material from the cell surface to the lysosomes or vacuoles.
After adsorption it gets penetrated into the host cell membrane and uncoating takes place by removing of its lipid envelope.
III. Replication and transcription:
After fusion the viral gene Called as Early gene and Late gene. The early gene take over the host cell then Viral DNA afterwards Viral RNA is synthesized. The viral enzyme RNA dependent RNA polymerase (transcriptase) is synthesize the mRNA which is then codes the viral protein and then multiplies.
IV. Synthesis of Nucleocapsid:
The Late genes directs the synthesis of capsid protein and viral nucleic acid then taken into the capsid to form "Nucleocapsid" and multiples of nucleocapsid are gets synthesized.
V. Releasing of Virion:
The virion which is now naked, means those with no layers around the nucleocapsid are then released by cell lysis.
BUDDING: In contrast, Viruses with envelope around its nucleocapsid are released by a process known as "Budding "
In this processes the foreign unwanted viruses are affected the human beings and gets multiplies by the above processes and infected with the viruses.
As same as the above principles the Coronaviruses are entered and affected the humans . Coronaviruses are enveloped RNA strand viruses and these are delivered their material into the nucleus of the host cell in cytoplasm. The spike glycoprotein which is present on the membrane and mediates the viral entry. And the replication , multiplication takes place in the host cells and releasing of virion then affecting the other cells.
If you wants to download this file, click the download button below then you will be get this file
- https://smartpharmainfo.blogspot.com/2020/07/zydus-cadila-gets-usfda-approval-for.html
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- https://smartpharmainfo.blogspot.com/2020/07/biophore-india-to-get-approval-for.html
Good information
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