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The origins of some immortal cell lines – for example, HeLa human cells – are from naturally occurring cancers. HeLa, the first immortal human cell line on record to be successfully isolated and proliferated by a laboratory, was taken from Henrietta Lacks in 1951 at Johns Hopkins Hospital in Baltimore, Maryland. [1]
Among the most commonly used cell lines are HeLa and Jurkat, both of which are immortalized cancer cell lines. [4] These cells have been and still are widely used in biological research such as creation of the polio vaccine, [5] sex hormone steroid research, [6] and cell metabolism. [7] Embryonic stem cells and germ cells have also been ...
The first edition of the Bacteriological Code in 1947 set a standardised system and authority for the classification of Bacteria. [30] A. R. Prévot's system [31] [32]) had four subphyla and eight classes, as follows: Eubacteriales (classes Asporulales and Sporulales) Mycobacteriales (classes Actinomycetales, Myxobacteriales, and Azotobacteriales)
Primary cell culture is the ex vivo culture of cells freshly obtained from a multicellular organism, as opposed to the culture of immortalized cell lines.In general, primary cell cultures are considered more representative of in vivo tissues than cell lines, and this is recognized legally in some countries such as the UK (Human Tissue Act 2004). [1]
Bacteria display a large diversity of cell morphologies and arrangements. Bacterial cellular morphologies are the shapes that are characteristic of various types of bacteria and often key to their identification. Their direct examination under a light microscope enables the classification of these bacteria (and archaea).
The three-domain system adds a level of classification (the domains) "above" the kingdoms present in the previously used five- or six-kingdom systems.This classification system recognizes the fundamental divide between the two prokaryotic groups, insofar as Archaea appear to be more closely related to eukaryotes than they are to other prokaryotes – bacteria-like organisms with no cell nucleus.
Archaea that live in extreme and harsh environments with low pH levels such as salt lakes, oceans, and in the gut of ruminants and humans are also known as extremophiles. In contrast, bacteria are found in various areas such as plants, animals, soil, and rocks. [27]
One reason for this classification was so that the group then often called blue-green algae (now cyanobacteria) would not be classified as plants but grouped with bacteria. [ 47 ] In 1977, Carl Woese proposed dividing prokaryotes into the Bacteria and Archaea (originally Eubacteria and Archaebacteria) because of the major differences in the ...