Chlorella

Chlorella is a genus of about thirteen species of single-celled or colonial green algae of the division Chlorophyta. The cells are spherical in shape, about 2 to 10 μm in diameter, and are without flagella. Their chloroplasts contain the green photosynthetic pigments chlorophyll-a and -b. In ideal conditions cells of Chlorella multiply rapidly, requiring only carbon dioxide, water, sunlight, and a small amount of minerals to reproduce. The name Chlorella is taken from the Greek χλώρος, chlōros/ khlōros, meaning green, and the Latin diminutive suffix -ella, meaning small. German biochemist and cell physiologist Otto Heinrich Warburg, awarded with the Nobel Prize in Physiology or Medicine in 1931 for his research on cell respiration, also studied photosynthesis in Chlorella. In 1961, Melvin Calvin of the University of California received the Nobel Prize in Chemistry for his research on the pathways of carbon dioxide assimilation in plants using Chlorella. Chlorella has been considered as a source of food and energy because its photosynthetic efficiency can reach 8%, which exceeds that of other highly efficient crops such as sugar cane.

Chlorella is a genus of about thirteen species of single-celled or colonial green algae of the division Chlorophyta. The cells are spherical in shape, about 2 to 10 μm in diameter, and are without flagella. Their chloroplasts contain the green photosynthetic pigments chlorophyll-a and -b. In ideal conditions cells of Chlorella multiply rapidly, requiring only carbon dioxide, water, sunlight, and a small amount of minerals to reproduce. The name Chlorella is taken from the Greek χλώρος, chlōros/ khlōros, meaning green, and the Latin diminutive suffix -ella, meaning small. German biochemist and cell physiologist Otto Heinrich Warburg, awarded with the Nobel Prize in Physiology or Medicine in 1931 for his research on cell respiration, also studied photosynthesis in Chlorella. In 1961, Melvin Calvin of the University of California received the Nobel Prize in Chemistry for his research on the pathways of carbon dioxide assimilation in plants using Chlorella. Chlorella has been considered as a source of food and energy because its photosynthetic efficiency can reach 8%, which exceeds that of other highly efficient crops such as sugar cane.

Reproduction

Reproduction occurs by the formation of autospores; zoospores or gametes are not known to be produced in Chlorella. In autosporulation, the contents of the cell divide into two, four or sometimes eight protoplasts. Each daughter protoplast rounds off, and are liberated by the rupture of the parent cell wall. On release, each autospore grows to become a new individual. The daughter cell may remain attached to the parent cell wall, thereby forming colonies of cells. The presence of sulphur in the culture medium is considered essential for cell division. It takes place even in the dark with sulphur alone as the source material but under light conditions nitrogen also required in addition. Pearsall and Loose (1937) reported the occurrence of motile cells in Chlorella. Bendix (1964) also observed that Chlorella produces motile cells which might be gametes. These observations have an important bearing on the concept of the life cycle of Chlorella, which at present is considered to be strictly asexual in character. Asexual reproduction in Chlorella ellipsoides has been studied in detail and the following four phases have been observed during the asexual reproduction. Growth phase: During this phase the cells grow in size by utilizing the photosynthetic products. Ripening phase: In this phase the cells mature and prepare themselves for division. Post ripening phase: During this phase, each mature cell divides twice either in dark or in light. The cells formed in dark are known as dark to light phase, cells again grow in size. Division phase: During this phase the parent cell wall ruptures and unicells are released.

Dietary supplement

Chlorella is consumed as a dietary supplement. Some manufacturers of Chlorella products have falsely asserted that it has health benefits, including an ability to treat cancer, for which the American Cancer Society stated "available scientific studies do not support its effectiveness for preventing or treating cancer or any other disease in humans". The United States Food and Drug Administration has issued warning letters to supplement companies for falsely advertising health benefits of consuming chlorella products, such as one company in October 2020. There is some support from animal studies of chlorella's ability to detoxify insecticides. Chlorella protothecoides accelerated the detoxification of rats poisoned with chlordecone, a persistent insecticide, decreasing the half-life of the toxin from 40 to 19 days. The ingested algae passed through the gastrointestinal tract unharmed, interrupted the enteric recirculation of the persistent insecticide, and subsequently eliminated the bound chlordecone with the feces.

Text derived from https://en.wikipedia.org/w/index.php?oldid=1333547595 under CC BY-SA 4.0; modifications have been made.