What is the Molecular Biology Behind Malaria?

The molecular biology of malaria involves the study of the genes and proteins that are involved in the life cycle of the Plasmodium parasites, as well as the ways in which the parasites interact with the human host.

The life cycle of the Plasmodium parasites involves several different stages and occurs both within the human host and within the mosquito vector.

1. When an infected mosquito bites a person, the parasites are transmitted from the mosquito's saliva into the person's bloodstream.

2. The parasites enter the liver and multiply, producing thousands of parasites called merozoites.

3. The merozoites are released into the bloodstream, where they enter red blood cells and multiply again.

4. As the parasites multiply within the red blood cells, they cause the cells to burst, releasing even more parasites into the bloodstream. This cycle of infection and destruction of red blood cells leads to the symptoms of malaria.

5. Some of the parasites that are released into the bloodstream during this process develop into a sexual form called a gametocyte.

6. When a mosquito bites an infected person and takes in a blood meal, it ingests the gametocytes along with the blood.

7. Inside the mosquito, the gametocytes mature and eventually produce more parasites, called sporozoites.

8. The sporozoites migrate to the mosquito's salivary glands, where they can be transmitted to a new human host when the mosquito bites again.

This cycle can continue, with the parasites being transmitted back and forth between humans and mosquitoes, unless the infection is interrupted by treatment or by the development of immunity in the human host.

Protein Modification of Plasmodium parasites (P. falciparum)

The malaria parasite Plasmodium falciparum modifies a number of proteins within the infected erythrocytes (red blood cells) in order to evade the host immune system and ensure its own survival. Some of the specific protein modifications that have been identified in P. falciparum-infected erythrocytes include:

1. Modification of cytoskeletal proteins: The cytoskeleton of the infected erythrocytes is altered by the parasite, leading to changes in the shape and deformability of the cells. This allows the infected erythrocytes to evade detection by the spleen, which normally removes damaged or abnormal red blood cells from circulation.

2. Modification of surface proteins: P. falciparum modifies the surface proteins of the infected erythrocytes, including those that are involved in adhesion to the endothelial cells lining the blood vessels. This allows the infected erythrocytes to "stick" to the blood vessel walls, a process called cytoadherence, which can lead to the obstruction of blood flow and the development of severe malaria.

3. Modification of enzymes: P. falciparum modifies a number of enzymes within the infected erythrocytes, including those involved in the breakdown of haemoglobin. This can lead to the release of toxic by-products, such as free haem, which can cause damage to the erythrocytes and other tissues.

4. Modification of metabolic pathways: P. falciparum modifies the metabolic pathways of the infected erythrocytes, including those involved in energy production and the synthesis of macromolecules. This allows the parasite to obtain the nutrients it needs to survive and multiply.

Why is this Important?

Understanding the protein modification characteristics of P. falciparum and the infected erythrocytes is important for the development of new antimalarial drugs and for the design of vaccines that can protect against malaria.

As P. falciparum is the most deadly/severe form of malaria I would like to go into detail as it relates to what that specific bacteria looks like. It can be observed under a microscope in several different stages of its life cycle.

1. Trophozoites: These are the actively multiplying forms of the parasite that are found within the red blood cells. Under the microscope, trophozoites appear as small, rounded structures with a distinct nucleus and cytoplasm. They may be difficult to see in a thin blood smear due to their small size, but they are more easily visible in a thick blood smear or in tissue sections.

2. Schizonts: These are the stages of the parasite that are responsible for the release of merozoites, the next stage in the life cycle. Schizonts are larger than trophozoites and contain multiple nuclei. They appear as rounded or oval structures within the red blood cells and can be seen in thick blood smears or tissue sections.

3. Merozoites: These are the stages of the parasite that are released from the red blood cells and enter new cells to start the cycle over again. Merozoites are small, elongated structures with a pointed end. They may be difficult to see in a blood smear due to their small size, but they can be observed in tissue sections or in cultures of infected red blood cells.

4. Gametocytes: These are the sexual stages of the parasite that are transmitted to the mosquito vector. Gametocytes are larger than merozoites and have a more rounded appearance. They can be seen in blood smears or in tissue sections.

5. Sporozoites: These are the stages of the parasite that are found in the mosquito vector and are responsible for the transmission of the infection to a new human host. Sporozoites are small, elongated structures with a pointed end. They can be observed in the salivary glands of the mosquito or in tissue sections.