Understanding Virus Characteristics, Body Structure, Types and Impacts

sinaumedia Literacy – Most of the causes of disease on earth come from organisms that cannot be seen by the naked eye, one of which is a virus. Viruses are living things that are parasitic because they need a host as a place to live, which then causes illness and death in other creatures. Check out a more complete explanation of the following viruses, Sinaumed’s!

DEFINITION OF VIRUSES

The word “virus” comes from the Latin, namely virion which means poison. The virus itself always develops from time to time, so it can be said that it is very difficult to die or disappear. In fact, it is possible that new viruses will emerge which sometimes can make humans or other living things sick.

Viruses are part of microorganisms. Named part of the microorganism because it is a living thing with a size of only a few microns or maybe smaller than that, because 1 micron is equal to 0.001 mm. Based on the definition of virus above, it can be said that a virus is a parasitic organism, which requires a host to survive. These microorganisms must find a host to reproduce, including through human cells.

Without hitching a ride on its host’s body, it cannot self-replicate. Some species of these organisms can even kill their host cells in order to reproduce. If it doesn’t find a host, the virus can’t live very long, Sinaumed’s.

VIRUS CHARACTERISTICS

Viruses are often debated over their status as living things because they cannot carry out their biological functions freely. Because of this characteristic, it is always associated with certain diseases, whether in humans (eg influenza and HIV), animals (eg bird flu), or plants (eg tobacco mosaic). Then what are the characteristics possessed by the virus? Here are some of them:

  1. Has only one type of nucleic acid which is covered by a capsid or protein coat. This nucleic acid is DNA or RNA.
  2. Its size is very small, which is between 25 – 300 nm. For 1 nm is equal to 10-9 m.
  3. The body of the virus is not cell-shaped. So the virus does not have a cell nucleus, plasma membrane, and cytoplasm.
  4. Can only live and reproduce in living cells or also known as obligate intracellular parasites.
  5. Is a creature metaorganism. A metaorganism is a transitional form between inanimate matter or having properties that can be crystallized and living things or can reproduce.
  6. Has several body shapes. The body shape of the virus is spherical, rod, T-shape, and cylindrical.

There are lots of questions about the virus itself. Is the virus a living thing? How do viruses reproduce? And others. This question is fairly common, and is also discussed in one of the Illustrated Books Secrets of Nature 23 – Virus Secrets by Soepri Ketjil. Sinaumed’s can learn about this in the book and Sinaumed’s can also buy it by clicking “Buy a Book” below.

VIRUSES BODY STRUCTURE

In general, the body structure of a virus consists of a nucleic acid and a capsid. In addition, these microorganisms also have additional structures, such as nucleic acids consisting of DNA or deoxyribo nucleid acid or RNA or ribonucleid acid . In general, the body structure of the virus consists of 4 main parts, namely the head, body contents, tail and capsid.

1. Head

Structure of Virus Head Viruses have a head containing DNA or RNA which is the genetic material for life. The contents of this head are protected by a capsid, which is a protein sheath composed of protein. The shape of the capsid is highly dependent on the type of virus. Capsids can be spherical, polyhedral, helical, or some other more complex shape. The capsid is composed of many capsomeres or protein sub-units.

2. Fill the Body

Virus body contents or commonly called virions are genetic material in the form of one type of nucleic acid (DNA or RNA). The type of nucleic acid possessed will affect the body shape of the virus. The contents of the body are usually in the form of RNA that is shaped like a cube, round, or polyhedral, for example in viruses that cause polyomyelitis, influenza, and inflammation of the mouth and nails.

3. Tail

The tail is part of the body structure of the virus which functions as a tool to attach itself to the host cell. The tail attached to the head generally consists of several plugged tubes filled with fine threads and fibers.

4. Capsid

The capsid is a layer in the form of a series of capsomeres in the body of the virus that functions as a wrapping for DNA or RNA. The function of this capsid is to form a body and protect the virus from external environmental conditions.

The structure of the viral capsid is the structure of the virus that is located outside the virus and contains quite a lot of subunits in the form of protein. These contents are better known as capsomeres. The shape of the capsid can be said to be quite diverse, so it can affect the shape of the virus itself.

History of the Discovery of Viruses

Certainly not many people know the history of the first discovery of the virus. Therefore, below I will explain a little about the first time the virus was discovered.

1. Adolf Mayer

When it comes to who was the first to discover a virus in this world, the answer is Adolf Meyer who is a scientist from Germany. He first discovered the virus in 1883 by observing tobacco leaves which had yellow spots.

After seeing this, Adolf Meyer began to do his research by extracting tobacco sap which then sprayed it on tobacco leaves that were in good health. The sap that has been sprayed turns out to make (healthy) tobacco leaves appear yellow spots.

Thanks to his curiosity, Adolf Meyer began to find out why tobacco leaves had yellow spots using a microscope. From his observations through a microscope it was found that the tobacco leaves (which had yellow spots) had no bacteria.

From that research and observation, Adolf Meyer concluded that tobacco leaves are unhealthy because they contain creatures that are smaller than bacteria.

2. Dmitry Ivanovsky

After the discovery of the virus was carried out by Adolf Meyer, then in 1892 there was a scientist named Dmitri Ivanovsky and he came from Russia. You could say that the research conducted by Dmitri Ivanovsky is almost the same as that of Adolf Meyer, it’s just that the difference lies in the filtering. The sap filtered by Dmitri Ivanovsky uses a bacterial filter.

The filter results are then sprayed onto the tobacco leaves which are still in good health. After being sprayed, healthy tobacco leaves turn sick. The results of this study are the same as Adolf Meyer’s where (healthy) tobacco leaves turn sick because of creatures that can make tobacco leaves unhealthy anymore.

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3. Martinus Beijerinck

Research on viruses continues to develop using tobacco leaves, it’s just that the research conducted by Martinus Bejerinck is more directed at eliminating or deactivating creatures that cause disease. He is a scientist who comes from the Netherlands.

Martinus Beijerinck uses alcohol to inactivate creatures that can make living things sick. As it turned out, the research still could not deactivate creatures that were smaller than bacteria and Martinus Beijeinck called them viruses that passed the filter.

4. Wendell Meredith Stanley

In 1935, there was a researcher from the United States, Wendell Merdith Stanley, who conducted research on creatures that could cause tobacco leaves to become sick. From the research conducted, he managed to crystallize the creature and then the disease that occurs in tobacco leaves is called Tobacco Mosaic Virus (TMV).

Virus Classification

Virus Classification Based on Host Cell Type

1. Plant Attack Virus

This virus can damage the plants you are planting and caring for, for example Tungro and TMV.

2. Human Attack Virus

There are many viruses that attack humans and some viruses are harmful to humans, such as the HIV influenza virus, the corona virus, the omicron virus, and others.

3. Animal Attack Virus

This animal-attacking virus can make the animal you care for fall sick or even die, for example bird flu, rabies, and so on.

4. Bacteria Attack Virus

One example of a bacterial attack virus is the T.

Classification of Viruses Based on Presence or Absence of Envelope in the Nucleocapsid

1. Enveloped Virus

Enveloped viruses are viruses in which there are glycoproteins and lipoproteins inside the envelope, for example Paramyxovirus, Herpesvirus, Togavirus, Rhabdovirus, and Poxyvirus .

2. Naked Viruses

Naked viruses are viruses that do not have a nucleopasid sheath, such as Adenovirus, Reovirus, Papovirus, and Picornavirus.

Classification of Viruses Based on the Type of Nucleic Acid

Some viruses are classified based on the type of nucleic acid, including:

1. DNA viruses

DNA viruses are viruses in which the nucleic acid is in the form of DNA, for example parvovirus .

2. RNA viruses

RNA viruses are viruses in which the nucleic acid content is in the form of RNA, for example picornavirus .

Virus Classification Based on Basic Forms

If classified according to the basic form, then the virus is divided into three types, viz

1. Helical Virus

This virus only has one axis of rotation in which the shape of the axis is like a long rod, the shape of a helix, and the nucleocapsid is easy to move or not rigid, for example the flu virus.

2. Complex Viruses

As the name suggests, this virus has a fairly complex structure when compared to other types of viruses, such as the smallpox virus.

3. Virus with Icohedral Shape

In contrast to helical viruses, the number of axes in this virus has two double rotations and its layout is only limited by 20 equilateral triangles, for example the polio virus.

Virus Classification Based on Genome Type and Replication

Type I viruses

This type I virus consists of double-stranded DNA and its reproduction is carried out by means of replication, for example Herpesvirus .

Type II viruses

Type II viruses consist of single-stranded DNA and their reproduction is carried out by means of replication, for example MVM viruses.

Type III viruses

Type II viruses, consisting of RNA with reliable threads and their reproduction is carried out by replication, for example Reovirus .

Type IV viruses

Type IV viruses consist of single-stranded (+) RNA and their reproduction is carried out by replication, for example polio virus.

Type V viruses

Type V virus consists of RNA with a single strand (-) and its reproduction is carried out by replication, for example the rabies virus.

Type VI viruses

Type VI viruses consist of single-stranded RNA (+) and DNA as an intermediary and their reproduction is carried out by reverse transcription, for example the AIDS virus.

Type VII viruses

Type VII viruses consist of double-stranded RNA with RNA as an intermediary and reproduce by reverse transcription, for example Heparnavirus .

Virus Classification Based on the Number of Capsomeres

1. Viruses with 32 capsomeres, such as Parvovirus .

2. Viruses with 60 capsomeres, such as Picornavirus .

3. Viruses with 72 capsomeres, such as Papovirus .

4. Viruses with 162 capsomeres, such as Herpesvirus .

5. Viruses with 252 caposmers, such as Adenovirus .

TYPES OF VIRUSES

1. DNA VIRUSES

DNA viruses are viruses whose genetic material is in the form of nucleic acids in the form of double-stranded strands. Inside the host cell, the DNA in the virus will undergo replication into several DNA and will also experience transcription into mRNA. The mRNA then undergoes translation to produce viral envelope proteins.

Still inside the host cell, viral DNA and proteins construct themselves into new viruses. mRNA will also form a destructing enzyme (lysozyme) so that the host cell lysis (destroys) and the viruses come out to infect other host cells. Examples of these viruses:

  • Papilloma
  • Polyloma
  • Parvovirus B19
  • Adenoviruses
  • Herpes simplex I (sores around the mouth)
  • Herpes simplex II (genital sores)
  • Varicella zoster (chickenpox)
  • Epstein-Barr virus
  • Cytomegalovirus
  • Vaccinia
  • Roseola
  • Cowpox
  • Smallpox
  • Bacteriophage
  • Hepatitis B virus
  • Smallpox virus
  • Transfusion Transmitted Virus
  • JC virus (progressive multifocal leukoencephalopathy)
  • Anellovirus
  • Salterprovirus

2. RNA VIRUSES

RNA virus is a virus whose genetic material is in the form of nucleic acid in the form of a single or double untwisted chain. Inside the host cell, the RNA in the virus will undergo reverse transcription to become an RNA-DNA hybrid and eventually form DNA. Furthermore, the viral DNA will enter the nucleus of the host cell, inserting into the host DNA. Viral DNA will damage the host DNA and form mRNA. mRNA will undergo translation to produce viral envelope proteins to form new viruses. Examples of these viruses:

  • HIV AIDS
  • Influenza
  • Hepatitis E Virus
  • Poliovirus
  • Paramyxovirus Paramyxovirus
  • Enteric viruses
  • Rubella virus
  • Yellow fever virus
  • Encephalitis virus
  • DHF RNA tumor virus (dengue fever)
  • Rabies Measles Rhinovirus (fever and runny nose)
  • Reovirus (diarrhoea)
  • Mumps
  • Rotavirus
  • enterovirus
  • Hepatovirus
  • ebola virus

One of the most well-known deadly viruses is the Ebola virus. Is the world’s most deadly disease, only a few weeks of patients infected with this virus can die. Approximately 90% of patients infected with the Ebola virus end in death.

The initial symptoms of the patient are similar to runny nose, fever, headache, diarrhea and weakness. In full, the book Deadly Ebola Virus by the Editors of Health Secret explains more about the Ebola virus, how to prevent it, and also what we need to prepare to deal with it. And you can also buy Sinaumed’s by clicking “Buy a Book” below.

Virus form

Viruses that we often know are usually in the form of a circle, but in reality there are many different shapes of viruses. Then, what are the forms of viruses that exist?

1. Viruses with filaments or threads

Like a thread, this virus can be said to have a fairly thin size, for example the Ebola virus.

2. Virus with a Round Shape

Round-shaped viruses are viruses that are generally known by many people, one example of this virus shape is the Human Immunodeficiency Virus (HIV).

3. A virus shaped like the letter T

This virus looks almost the same as the letter T. Viruses with this shape, for example, exist in viruses that interfere with the health of Eschirichia coli bacteria , also known as bacteriophages.

4. Virus with Stem Shape

We can see this stem virus in the Tobacco Mosaic Virus (TMV).

5. Viruses with Stem Shapes and Oval Edges

In this rod-shaped virus with an oval tip, one example is the Rhabdovirus .

6. Virus with Polyhedral Shape

One example of a virus that has a polyhedral shape is Adenovirus .

POSITIVE IMPACT OF THE VIRUS

The term virus has the connotation of something deadly, but this bad reputation does not apply universally because viruses are not always harmful. There are several viruses that are beneficial to human life, here are some of them:

1. HEALTH SECTOR

Some viruses that play a role in the health sector as cancer prevention and body health control are as follows:

  • Viruses play a role in the manufacture of some vaccines. Such as polio vaccine, measles, smallpox, cancer, and others. The content contained in the benefits of the vaccine is a virus that is dead or weakened and causes fever for the person who is injected with the vaccine. Then, the immune system will record it and form antibodies in the body. So if these diseases come to attack, the body’s immune system prevents them from entering.
  • Some viruses play a role in controlling some cancer cells which will be killed by using the cell-killing effects of viruses directly, rather than using the immune system.
  • Virus-directed enzyme prodrug therapy (VDEPT), is a viral therapy in which the target cells are infused with enzymes and can activate and deactivate precursors and cytotoxics which are arranged systematically.
  • Make antitoxin. This antitoxin is formed by combining viral DNA and beneficial genes. Then, viral DNA connects human DNA with bacterial DNA. Thus, bacterial cells contain human genes that can produce antitoxins.
  • Ingredients for insulin. A cancer-causing virus is grafted with insulin-producing genes into bacteria. Thus, the bacteria can multiply and produce insulin.
  • Gene therapy by changing the gene that causes infection into a gene that cures
  • Bacteriophages has been successful in curing typhus in chickens and dysentery. In 1921, bacteriophages were used to fight the Staphylococcus virus that attacks the skin. Its working system is to stick to the pathogenic bacteria and infect it until the bacteria die.
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2. AGRICULTURE SECTOR

The benefits of viruses in agriculture can be seen from the use of biological organisms in controlling damage by pests or what is commonly called biological control. This activity is already widely used in agricultural systems, here are some of them:

  • Insect pest control via Baculoviruses, or a group of viruses that can infect insects and other arthropods. Baculoviruse implanted in agricultural crop genes. Then the insect larvae eat the plant. The virus then infects the cells and grows in the larvae’s body and over time damages the body’s tissues.
  • Integrated Pest Management. The application of IPM relies on biological agents. Thus, reducing the use of pesticides which can cause environmental pollution in Sinaumed’s.

3. FIELD OF SCIENCE

Science development. Viruses have been used extensively in molecular and cellular studies to manipulate and understand the functions of cells. In addition, viruses can also be used for genetic research, such as DNA replication, transcription, RNA formation, protein formation, basic DNA for body resistance.

NEGATIVE IMPACT OF THE VIRUS

1. DISEASES IN ANIMALS

Rabies virus or Rhabdhovirus virus is a virus that can attack the human central nervous system and brain. As a result, the body will not be able to move and cause hydrophobia. This virus is transmitted to humans through the bites of warm-blooded animals that have contracted the rabies virus, such as bites from dogs, monkeys, bats and raccoons.

Therefore, it is always good to be careful with wild animals and vaccinate pets at home. Apart from that, there was also the Avian Influenza Virus Type A (H5N1), which was popular in Indonesia due to the outbreak at that time. This virus apparently attacks poultry, such as birds and chickens. The dangerous thing is that this virus can be transmitted to humans.

This type A influenza virus can cause epidemics in animals (epizootic) and various animal species in a wide area (panzootic), so that it can transmit quite a number of animals in one area. Symptoms of contracting this virus include respiratory problems, vomiting, diarrhea and general flu symptoms.

2. DISEASES IN PLANT

Tobacco Mozaic Virus is the cause of mosaic disease in tobacco plants. In fact, this virus is the forerunner to the naming of the word ‘virus’ and the branch of science studying viruses (virology). This virus is able to stunt plants due to infection in plant leaves.

Symptoms of this virus consist of a light green color on the leaves of plants resembling a ‘mosaic’ pattern or stripes of light green and dark green on the leaves. There is a mutation that occurs in this virus, apparently able to attack other plants besides tobacco. For example, pumpkin, beans, cucumbers, potatoes and so on.

In addition, there is also the Rice Tungro Bacilliform Virus which can threaten rice growth, because it causes tungro disease. The symptoms of this virus are the stunting of the rice plants and the red to orange-yellow color, which results in a reduced amount of grain produced by Sinaumed’s.

3. DISEASES IN HUMANS

Some of the diseases that humans suffer are generally caused by a virus attack in the body. Viruses have a microscopic size that ranges from 20-300 millimicrons. Viruses are acellular or do not have cells, so viruses will only reproduce in living cells. The virus will attack immunity or immunity when the immune system is weak. The following are various biological viruses that threaten human health, Sinaumed’s:

HIV virus

The HIV virus is a virus that will weaken the human body’s immunity. This will cause the body to be susceptible to infection or other diseases. HIV means Human Immunodeficiency Virus. The cause of this virus is the process of physical contact with HIV sufferers through unhealthy sexual intercourse, the use of used syringes with HIV sufferers, the use of tattoo and body piercing tools.

Not only that, the virus can also be transmitted if there is contact through bodily fluids (blood, semen, etc.) of someone with HIV, such as a mother with HIV who transmits it to her baby. This virus will not be transmitted due to direct daily contact, for example touching, shaking hands, and hugging.

If this virus continues to grow, this virus can cause AIDS (Acquired Immunodeficiency Syndrome or Acquired Immune Deficiency Syndrome).

Ebola Virus

The Ebola virus was first discovered near the Ebola river in Zaire (Congo) around 1976. Ebola is one of the deadliest viruses for humans. The definition of the Ebola virus is a virus that causes fever, diarrhea and bleeding. The spread of the virus through contact with objects that have been contaminated with the patient’s body fluids. Unfortunately, until now the treatment for the Ebola virus has not been found, as is the case with the HIV virus.

Corona Virus

Corona Paramyxovirus virus attacks the respiratory system so that this virus can be transmitted if humans breathe air containing this virus. The worst thing is that this virus can cause Severe Acute Respiratory Syndrome (SARS). Corona virus is a type of virus that can cause a person to suffer from pneumonia which infects a person’s respiratory tract. This dangerous virus spreads faster than the HIV virus and the Ebola virus.

The symptoms of this corona virus are almost the same as when someone has the flu, so sometimes for some people when they feel these symptoms they think that they have the flu. In addition, the cause of the corona virus can come from splashing water (when sneezing) and touching other people’s hands.

After the Covid-19 Virus appeared, Wuhan and other areas in China were locked down. Until March 7, 2020, less than 90 days after the initial outbreak in Wuhan, Italy did the same. Indonesia itself has regulations regarding health quarantine, such as home, regional, hospital quarantine to Large-Scale Social Restrictions.

The book, Preparedness Guide for Corona Virus by Tess Pennington, also discusses everything you need to know in preparing for quarantine, when someone is declared free from isolation, choosing masks, respirators and gloves. Of course, Sinaumed’s can buy and study this by clicking “Buy a Book” below.

Herpes Simplex virus

The Herpes Simplex virus is different from other viruses because the Herpes Simplex virus attacks human skin. The virus, commonly known as HSV, can cause sexually transmitted diseases for both men and women, causing blisters in the intimate area. The spread of this virus is generally due to sexual contact with people who are infected with this virus and pregnant women who transmit it to their unborn babies.

Dengue virus

Dengue virus can cause dengue hemorrhagic fever (DHF). This virus is transmitted by the bite of the Aedes aegypti mosquito . One of the most important forms of prevention so as not to contract this virus is to maintain the cleanliness of the surrounding environment, such as cleanliness of bathtubs, trash cans and gutters.

Poliomyelitis Virus

The Poliomyelitis Virus is one of the oldest types of viruses in the world because it has been known since the late 18th century. Generally, this virus will attack children aged around 3-5 years. This virus can cause muscle weakness to paralysis of the legs. Symptoms of this virus include fever, joint pain, bone to muscle pain, muscle cramps and others. The polio virus can be transmitted through human-to-human contact, such as feces (feces) contaminated with the virus. And, generally this virus can infect other family members who live in the same house.

Omicron virus

The Omicron virus is a variant form of the corona virus. In several sources, many scientists say that the Omicron virus appears because of a unique combination of more than 50 mutations. The mutations are arguably more numerous than the Delta variant which only has 7 mutations. Therefore, the omicron virus is dangerous, so everyone must take care of each other so that this virus does not spread quickly.

Thus the definition, characteristics, structure, types, positive and negative impacts of the virus.