Brief Notes on the History of Mitochondria!
Distributed in the matrix of cell are various particles of different sizes called cytoplasmic constituents or organelles. They include rounded, globular, filamentous or granular mitochondria, elongated secretory particles of Golgi apparatus, network of endoplasmic reticulum, plastids, centrosomes and lysosomes. Besides these, vacuoles and metaplastic bodies are also present in certain plant cells.
Mitochondria (Gr., Mito, thread; chondrion, granule) are thread-like or granular structures of eukaryotic cells. These are lacking in bacterial cells. Mitochondria are the ‘power plants’ which by oxidation, release the energy contained in the fuel molecules or nutrients and make other- forms of chemical energy. The main function of mitochondria is oxidative phosphorylation, which is an exergonic reaction, meaning that it releases energy.
In prokaryotes, oxidation of organic material is carried out by plasma membrane enzymes. In blue-green algae, the membrane is also able to perform photosynthesis.
Kolliker (1880) was the first who observed the granules (mitochondria) in muscle cells of insects. He termed them as ‘sarcosomes’. Flemming (1882) named the mitochondria as fila. Altmann in 1894 observed them and they were called Altmann’s granules bio blasts.
The term ‘mitochondria’ was applied by Benda (1897-98) to these thread-like granules which were described as cytomicrosomes by Velette St. George. Benda stained mitochondria with alizarin and crystal violet.
About the same time Michaelis (1900) found that mitochondria can be stained in vivo by Janus green B, and Lewis and Lewis (1914) made extensive study of mitochondria in living cells, emphasizing their sensitivity to metabolic conditions.
Bensley and Hoerr (1934) first of all isolated the mitochondria from the the site for the cellular respiration shown by Hogeboom et al., (1948). Lehninger and Kennedy (1948) using the technique of Hogeboom et al., reported that the mitochondria catalyzes all the reactions of citric acid cycle, fatty acid oxidation and coupled phosphorylation.
In 1894, Altmann first described mitochondria (calling them ‘bioblasts’) and predicted their association with cellular oxidation. Warburg (1913) observed that respiratory enzymes were associated with cytoplasmic particles.
Presence of DNA molecule in the mitochondria was observed by Nass in 1963. The entire mitochondrial groups of cells were designated as chondriosomes. Furthermore, in literature, we find various terms like plastosomes, plastochondria, plastoconts, myochondria, chondrioplasts, etc., used for chondriosomes.