The first observations of intracellular structures that probably represented mitochondria were published in the 1840s. Richard Altmann, in 1890, established them as cell organelles and called them "bioblasts". The term "mitochondria" was coined by Carl Benda in 1898. Leonor Michaelis discovered that Janus green can be used as a supravital stain for mitochondria in 1900. In 1904, Friedrich Meves, made the first recorded observation of mitochondria in plants in cells of the white waterlily, "Nymphaea alba" and in 1908, along with Claudius Regaud, suggested that they contain proteins and lipids. Benjamin F. Kingsbury, in 1912, first related them with cell respiration, but almost exclusively based on morphological observations.
History of discovery and research
Mitochondrion
Mitochondrion | History of discovery and research
Richard Altmann. Richard Altmann Richard Altmann. Richard Altmann
the mitochrondria is the powerhouse of the cell
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who was the first to discover it?
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The first observations of intracellular structures that probably represented mitochondria were published in the 1840s. Richard Altmann, in 1890, established them as cell organelles and called them "bioblasts". The term "mitochondria" was coined by Carl Benda in 1898. Leonor Michaelis discovered that Janus green can be used as a supravital stain for mitochondria in 1900. In 1904, Friedrich Meves, made the first recorded observation of mitochondria in plants in cells of the white waterlily, "Nymphaea alba" and in 1908, along with Claudius Regaud, suggested that they contain proteins and lipids. Benjamin F. Kingsbury, in 1912, first related them with cell respiration, but almost exclusively based on morphological observations.
Mitochondrion | History of discovery and research
The first high-resolution electron micrographs appeared in 1952, replacing the Janus Green stains as the preferred way of visualizing the mitochondria. This led to a more detailed analysis of the structure of the mitochondria, including confirmation that they were surrounded by a membrane. It also showed a second membrane inside the mitochondria that folded up in ridges dividing up the inner chamber and that the size and shape of the mitochondria varied from cell to cell.
Mitochondrion | History of discovery and research
Lewis was among the first scientists to observe the dynamics of mitochondria in living cells. In 1915 Margaret and Warren Lewis published a comprehensive analysis of the shapes and movements of mitochondria in cultured cells. Lewis's pioneering time-lapse studies included observations of mitochondrial movement toward and away from the centrosome, mitochondrial fission, and mitochondrial fusion. In the same paper, Lewis presented perhaps the first descriptions of stress-induced mitochondrial fragmentation and mitophagy.
Margaret Reed Lewis | Cell biology
And, together with Daniel Mazia, he was the first to isolate the mitotic apparatus and subject it to biochemical study. This work demonstrated conclusively the existence of the mitotic spindle and initiated the modern biochemical study of mitosis.
Katsuma Dan | Introduction
Mazia's research focused mainly on processes of mitosis , and was the first to isolate a spindle apparatus from a cell undergoing cell division. This research was done in conjunction with Katsuma Dan where they completed the first successful isolation of a mitotic apparatus from sea urchin eggs. This was a discovery that shocked the cell biology community. This discovery ended doubt of what the apparatus looked like, as well as opened a variety of new questions about the makeup of the apparatus, and how the appearance and disappearance of the structure was controlled. He never lost interest in the apparatus, and continued to research it throughout his career.
Daniel Mazia | Isolating the mitotic spindle
He was the first to use electron microscope to study biological cells. Earlier electron microscopes were used only in physical researches. His first electron microscopic study was on the structure of mitochondria in 1945. He was given American citizenship in 1941. He discovered that mitochondria are the "power houses" of all cells. He also discovered cytoplasmic granules full of RNA and named them "microsomes", which were later renamed ribosomes, the protein synthesizing machineries of cell. With his associate, Keith Porter, he found a "lace-work" structure that was eventually proven to be the major structural feature of the interior of all eukaryotic cells.
Albert Claude | Career
(The more related two species are, the more mtDNA/RNA mutations will be the same in their mitochondrial genome). Using these techniques, it is estimated that the first mitochondria arose around 1.5 billion years ago. A generally accepted hypothesis is that mitochondria originated as an aerobic prokaryote in a symbiotic relationship within an anaerobic eukaryote.
Human mitochondrial genetics | Genetic code variants
Wallin was the first to experimentally investigate the origin of mitochondria, particularly in relation to their similarities with certain bacteria. His first paper in 1922 described the staining techniques for bacterial cells, and found that the techniques were equally good for staining mitochondria. He concluded that "bacteria and mitochondria have a similar chemical constitution". His subsequent paper (in the same year and same journal) further strengthened his assumptions. In addition, he observed in his study of blue green algae that chloroplasts are "bacteria or bacteria-like organisms that accepted the leisure of a symbiotic partnership in the struggle for existence". He made a summary conclusion that: Wallin was aware that he needed to culture mitochondria isolated from cell in an independent environment.
Ivan Wallin | Origin of mitochondria
Mitochondrial DNA was discovered by Nash and Margit in 1963. One to many double stranded mainly circular DNA is present in mitochondrial matrix. Mitochondrial DNA is 1% of total DNA of a cell. It is rich in guanine and cytosine content. Mitochondria of mammals have 55s ribosomes.
Mitochondrial matrix | Introduction
Mitochondrial DNA was discovered in the 1960s by Margit M. K. Nass and Sylvan Nass by electron microscopy as DNase-sensitive threads inside mitochondria, and by Ellen Haslbrunner, Hans Tuppy and Gottfried Schatz by biochemical assays on highly purified mitochondrial fractions.
Mitochondrial DNA | History
In the following years, the mechanism behind cellular respiration was further elaborated, although its link to the mitochondria was not known. The introduction of tissue fractionation by Albert Claude allowed mitochondria to be isolated from other cell fractions and biochemical analysis to be conducted on them alone. In 1946, he concluded that cytochrome oxidase and other enzymes responsible for the respiratory chain were isolated to the mitochondria. Eugene Kennedy and Albert Lehninger discovered in 1948 that mitochondria are the site of oxidative phosphorylation in eukaryotes. Over time, the fractionation method was further developed, improving the quality of the mitochondria isolated, and other elements of cell respiration were determined to occur in the mitochondria.
Mitochondrion | History of discovery and research
In Gif-sur-Yvette, Bernard Dujon started to study a strange genetic phenomenon, linked to mitochondrial genetics, whose study was still in infancy. When crossing two haploid yeast species carrying different mitochondrial mutations, conferring the resistance to erythromycin or to chloramphenicol, allele segregation did not follow mendelian rules and recombinants appeared in mysterious proportions. At that time, no one had any idea of the genetic content of mitochondria, except that it contained DNA. Bernard Dujon was studying a particular mitochondrial locus, called "omega", that could be present as two different alleles, "omega+" or "omega-". Genetic crosses between yeast cells carrying different alleles led to highly distorted inheritance in the progeny, since almost all cells ended up carrying the "omega+" allele! In 1974, he proposed a model in which gene conversion of the "omega-" allele to "omega+" was achieved by homologous recombination, replacing one allele by the other, copying in the process the flanking erythromycin and chloramphenicol mutations.
Bernard Dujon | The early years : discovery of the first homing endonuclease
Carl Benda (30 December 1857 Berlin – 24 May 1932 Turin) was one of the first microbiologists to use a microscope in studying the internal structure of cells. In an 1898 experiment using crystal violet as a specific stain, Benda first became aware of the existence of hundreds of these tiny bodies in the cytoplasm of eukaryotic cells and assumed that they reinforced the cell structure. Because of their tendency to form long chains, he coined the name "mitochondria" ("thread granules"). These bodies had first been noted in 1857 by the physiologist and pioneer of the light microscope, Albert von Kölliker, and were later termed "bioblasts" by Richard Altmann in 1886.
Carl Benda | Introduction
Ivan Emanuel Wallin (22 January 1883 – 6 March 1969) was an American biologist who made the first experimental works on endosymbiotic theory. Nicknamed the "Mitochondria Man", he claimed that mitochondria, which are cell organelles, were once independent bacteria, as supported by his comparative studies and culture of isolated mitochondria. From 1922, he published a series of papers titled "On the nature of mitochondria" in the "American Journal of Anatomy" which became the experimental foundations of his claims. He was the first person to specifically postulate that eukaryotic organelles originated from bacteria, and that symbiosis is a major force in creation of new species.
Ivan Wallin | Introduction
The hydrogen hypothesis is a model proposed by William F. Martin and Miklós Müller in 1998 that describes a possible way in which the mitochondrion arose as an endosymbiont within an archaeon (classified as an undoubted prokaryote at that time), giving rise to a symbiotic association of two cells from which the first eukaryotic cell could have arisen (symbiogenesis). According to the hydrogen hypothesis:
Hydrogen hypothesis | Introduction
He and Basil Lythgoe proved this to be the case. He gained his second PhD in 1952. He later worked on the selective phosphorylation of nucleosides to form nucleotides. This was the beginning of a lifelong career, and led to the chemical structures of RNA and, by inference, DNA.
Daniel McGillivray Brown | Biography
Around this time, the first proto-mitochondrion was formed. A bacterial cell related to today's "Rickettsia", which had evolved to metabolize oxygen, entered a larger prokaryotic cell, which lacked that capability. Perhaps the large cell attempted to digest the smaller one but failed (possibly due to the evolution of prey defenses). The smaller cell may have tried to parasitize the larger one. In any case, the smaller cell survived inside the larger cell. Using oxygen, it metabolized the larger cell's waste products and derived more energy. Part of this excess energy was returned to the host. The smaller cell replicated inside the larger one.
History of Earth | Emergence of eukaryotes
Piotr Słonimski did pioneering work on yeast mitochondrial genetics. He was one of the first to show that genetic information is passed outside of the nucleus in mitochondria, and his subsequent, much cited work led to establishment of the field of mitochondrial genomics. In 1980, he discovered that some parts of the introns in yeast mitochondria encode an enzyme—which he called a maturase—that aids the splicing and the maturation of mRNA.
Piotr Słonimski | Scientific achievements
Daniel Mazia (December 18, 1912 – June 9, 1996) was an American cell biologist, best known for his research that isolated the cell structures responsible for mitosis. His research was the gateway for many later discoveries about the cell cycle, cell division, and many other areas in cell biology.
Daniel Mazia | Introduction
His early experiment was a failure using tissue samples from guinea pig, dog, and human blood. However, he succeeded in obtaining a mitochondrial culture with liver of fetal and newborn rabbits. He reported his findings in 1924 with a remark that "mitochondria are, in reality, bacterial organisms, symbiotically combined with the tissues of higher organisms." He continued with prolific publications. The series of his papers titled "On the nature of mitochondria" reached nine in 1925. He gave a full description of his experiments and theories on mitochondria in his 1927 book "Symbionticism and the Origin of Species". Although he claimed that his experiments were performed with utmost care, critics rejected them on the grounds of possible contamination, and Wallin and his works were largely forgotten, until Lynn Margulis introduced a more complete endosymbiotic theory with better evidences in 1967.
Ivan Wallin | Origin of mitochondria
Other classics include: identification of how skeletal bones grow through osteoblast deposition and osteoclast remodeling, early discovery of the biogenesis and metabolism of thyroxine and detection of triiodothyronine, early prediction of DNA semiconservative replication published days after the Watson and Crick Nature article, the discovery of axonal transport, the Warshawsky et al. finding that nascent proteins are processed from the rough endoplasmic reticulum through the Golgi apparatus into pancreatic zymogen granules (made in hot competition with the Palade lab at Rockefeller University), the first realization that the Golgi apparatus is the site of terminal glycosylation, the discovery of the cell coat, the cellular biogenesis of collagen, and new insights into the ultrastructure of basement membrane.
Charles Philippe Leblond | Other studies
The nucleus was the first organelle to be discovered. What is most likely the oldest preserved drawing dates back to the early microscopist Antonie van Leeuwenhoek (1632–1723). He observed a "lumen", the nucleus, in the red blood cells of salmon. Unlike mammalian red blood cells, those of other vertebrates still contain nuclei. The nucleus was also described by Franz Bauer in 1804 and in more detail in 1831 by Scottish botanist Robert Brown in a talk at the Linnean Society of London. Brown was studying orchids under the microscope when he observed an opaque area, which he called the "areola" or "nucleus", in the cells of the flower's outer layer.
Cell nucleus | History
The spindle pole bodies — the large structures in yeast cells which act as the foci to which chromosomes are moved during mitosis — have been purified and a low resolution structure of them deduced by John Kilmartin. A continuing interest has been the structure of chromosomes. This was initiated by a visitor, Roger Kornberg, who discovered the first level of condensation of DNA, the nucleosome, and continues with the focus on understanding the higher orders of folding DNA.
MRC Laboratory of Molecular Biology | Cell biology
Between the 1930s and 1950s, Fritz Lipmann and others established the role of ATP as the universal carrier of energy in the cell, and mitochondria as the powerhouse of the cell. Such traditionally biochemical work continued to be very actively pursued throughout the 20th century and into the 21st.
History of biology | Biochemistry, microbiology, and molecular biology
In 1913, particles from extracts of guinea-pig liver were linked to respiration by Otto Heinrich Warburg, which he called "grana". Warburg and Heinrich Otto Wieland, who had also postulated a similar particle mechanism, disagreed on the chemical nature of the respiration. It was not until 1925, when David Keilin discovered cytochromes, that the respiratory chain was described. In 1939, experiments using minced muscle cells demonstrated that cellular respiration using one oxygen atom can form two adenosine triphosphate (ATP) molecules, and, in 1941, the concept of the phosphate bonds of ATP being a form of energy in cellular metabolism was developed by Fritz Albert Lipmann.
Mitochondrion | History of discovery and research
At the University of California, San Francisco, Hyman investigated the interaction between chromosomes and microtubules that create the mitotic forces that separate chromosomes in the lab of Tim Mitchison. He also created a number of tools that are used today:
Anthony A. Hyman | Research
Many seminal discoveries have been published in the journal, including the first descriptions of numerous cellular functions and structures, such as the secretory pathway, mitochondrial and chloroplast DNA, microtubules, intermediate filaments, tight junctions (including occludins and claudins), adherens junctions, and cadherins.
Journal of Cell Biology | History
His laboratory at IMBB was the first to commence "Caenorhabditis elegans" research in Greece. Among the notable discoveries of his team are the sophisticated molecular mechanisms, by which diverse physiological signals are integrated to modulate cellular mitochondrial content, protein synthesis, and energy homeostasis during ageing. These studies revealed intricate signaling pathways that coordinate mitophagy and mitochondrial biogenesis, to determine the number of mitochondria in cells, under stress and during ageing. Work from his lab implicated autophagy, lysosomal function, endocytosis, intracellular calcium homeostasis and specific proteolytic enzymes as major contributors to necrosis and neurodegeneration. His group developed, for the first time, experimental heat stroke models; and identified mechanisms protecting against heat cytotoxicity and other necrotic insults.
Nektarios Tavernarakis | Research and scientific achievements
The Rickettsiales are widely believed to be the closest relatives to mitochondria. Based on the fact that the "Midichlorian" genes for the flagellum and for the cbb3 cytochrome oxidase were proven to be ancestral, the genes were inferred to have been present in the bacterium that established the symbiosis with the ancestor of the eukaryotic cell, which became the mitochondrion. Hence, sequencing the genome of "M. mitochondrii" allowed an improved reconstruction of the mitochondrion's hypothetical free-living ancestor: It was a motile bacterium able to survive in microaerophilic conditions. Both these characteristics may have played an important role in the beginning of the symbiosis between the eukaryotic cell and the mitochondrion.
Midichloria | "Midichloria" and the origin of mitochondria
Bütschli, Schneider and Fol might have also claimed the discovery of the process presently known as "mitosis". In 1873, the German zoologist Otto Bütschli published data from observations on nematodes. A few years later, he discovered and described mitosis based on those observations.
Mitosis | Discovery
Since obtaining an independent position at the University of California, Davis, Nunnari and colleagues have investigated the molecular mechanisms underlying mitochondrial fission and fusion and explored the structure and function of membrane contact sites that link mitochondria with other organelles. Nunnari was named editor-in-chief of "The Journal of Cell Biology" in August, 2015, becoming the first woman to serve in this position. She is a member of the American Society for Cell Biology, and has been elected to serve as the society's president in 2018. She is also a member of the American Society for Biochemistry and Molecular Biology. In May 2017, Nunnari was elected as a member of the National Academy of Sciences.
Jodi Nunnari | Introduction
His laboratory developed the first cell-free systems for studying the biochemistry of DNA replication in human cells, enabling the identification and functional characterization of components of the human replication machinery.
Thomas J. Kelly (scientist) | Introduction
It was later determined that the lateral border Kent was referring to was in fact the oral aperture of "Trimastix", which also contained a fourth flagella . Today, the morphology of "Trimastix" is better understood, including details not initially observed by Kent, such as Trimastix lacking a conventional mitochondrion. Current research indicates that despite there being no strong evidence that the organelle can produce ATP, there are many mitochondrial functions that it appears to have maintained .
Trimastix | History of Knowledge
These ideas were summarized in a seminal review in 1967. He also was the first to develop video microscopy, and wrote a major textbook on the subject. Consistent with Inoué's pioneering ideas, it is now widely believed that chromosome movement during mitosis is powered by microtubule depolymerization. We also know that force generation by polymerization and depolymerization of cytoskeletal protein fibers is perhaps the most ancient of motile mechanisms within cells, whose use extends back to bacteria.
Shinya Inoué | Research
Alexander Friedenstein and his colleagues first identified osteoprogenitor cells in multiple mammalian tissues, before any genetic or morphological criteria were put in place for bone marrow or connective tissues. Osteoprogenitor cells can be identified by their associations with existing bone or cartilage structures, or their placement in the embryo, as the sites for osteogenesis and chondrogenesis are now known.
Osteochondroprogenitor cell | Discovery
In 1956 Denham Harman first postulated the free radical theory of ageing, which he later modified to the mitochondrial free radical theory of ageing (MFRTA). He found ROS as the main cause of damage to macromolecules, known as “ageing”. He later modified his theory because he found that mitochondria were producing and being damaged by ROS, leading him to the conclusion that mitochondria determine ageing. In 1972, he published his theory in the Journal of the American Geriatrics Society.
Mitochondrial theory of ageing | History
The first contribution of Roland Douce was the characterization of cardiolipin, the major lipid of the mitochondrial membrane of plants and animals, as phosphatidyl ethanolamine. He then considerably improved the methods of purification of chloroplasts and mitochondria, and obtained the first envelope preparations. He was the first to show that the chloroplast shell is the site of biosynthesis of galactolipids and in particular MGDG, monogalactosyldiacylglycerol. With his team, he will characterize the lipid and protein components of the envelope of the plastids. He will succeed in separating the inner and outer shells. This work will pave the way for a detailed analysis of the chloroplast, its envelopes and functions .
Roland Douce | Main discoveries
In 1981, Horwich moved back to New Haven, Connecticut for a postdoctoral fellowship at Yale University School of Medicine. He worked in the laboratory of Leon Rosenberg. In 1984, he moved across the hall from Rosenberg's lab to start his own laboratory as an assistant professor in the department of genetics. He still collaborated with members of the Rosenberg laboratory, including Wayne Fenton. As an independent researcher, Horwich asked whether the pathway that imports an enzyme called ornithine transcarbamylase (OTC) into the mitochondria of mammalian cells also could work in yeast. In 1987, during a genetic screen in yeast, Horwich and his colleagues stumbled across a protein folding function inside mitochondria.
Arthur L. Horwich | Research
Using Atomic force microscope on live cells, Jena was the first to report the discovery of a new cellular structure the Porosome in the mid 1990s. The Porosome are permanent supramolecular structures at the cell Plasma membrane, where secretory Vesicle (biology and chemistry) dock and fuse to release intravesicular contents to the outside of the cell. This discovery was a major breakthrough in our understanding of cell secretion. The Porosome, has been determined as the universal secretory machinery in cells, from exocrine cells of the pancreas, to neuroendocrine cells, and neurons. Jena and his research team has determined the structure and dynamics of the Porosome in live cells, at nm resolution and in real time.
Bhanu Pratap Jena | Scientific Discoveries
Till & McCulloch are James Till and Ernest McCulloch who, while studying the effect of radiation on the bone marrow of mice at the Ontario Cancer Institute, in Toronto, demonstrated the existence of multipotent stem cells in 1961.
Till &amp; McCulloch | Introduction
This innovation may have come from primitive eukaryotes capturing oxygen-powered bacteria as endosymbionts and transforming them into organelles called mitochondria. The earliest evidence of complex eukaryotes with organelles (such as mitochondria) dates from .
Paleontology | History of life
In 1899 he discovered the first acritarch fossil cells, a Precambrian algal phytoplankton he named "Chuaria". Lastly, in 1914, Walcott reported "minute cells and chains of cell-like bodies" belonging to Precambrian purple bacteria.
Paleobiology | Paleobiologists
Resident Distinguished Scientist Shinya Inoué's innovations in polarized light microscopy and video imaging since the 1950s have been instrumental in clarifying the cellular events of mitosis, including his discovery of the spindle fibers. The MBL has long been a center for the world's experts in cell division. In the early 1980s, Tim Hunt, Joan Ruderman and others at the MBL identified the first of a class of proteins that regulate the cycle of cell division (cyclin). Hunt was awarded a Nobel Prize in 2001 for this work (Hunt, 2004). In 1984, Ron Vale, Michael Sheetz, and others discovered kinesin, a motor protein involved in mitosis and other cellular processes, during summer MBL research.
Marine Biological Laboratory | Cell, developmental, and reproductive biology
The term "dendrites" was first used in 1889 by Wilhelm His to describe the number of smaller "protoplasmic processes" that were attached to a nerve cell. German anatomist Otto Friedrich Karl Deiters is generally credited with the discovery of the axon by distinguishing it from the dendrites. Some of the first intracellular recordings in a nervous system were made in the late 1930s by Kenneth S. Cole and Howard J. Curtis. Swiss Rüdolf Albert von Kölliker and German Robert Remak were the first to identify and characterize the axon initial segment. Alan Hodgkin and Andrew Huxley also employed the squid giant axon (1939) and by 1952 they had obtained a full quantitative description of the ionic basis of the action potential, leading the formulation of the Hodgkin–Huxley model.
Dendrite | History
This discovery effectively established the field of single-cell genomics. Awards
Nicholas Navin | Introduction
They were discovered in 2010 by Mari Dezawa and her research group. Clinical trials for acute myocardial infarction, stroke, epidermolysis bullosa and spinal cord injury are conducted by Life Science Institute, Inc., a group company of Mitsubishi Chemical Holdings company.
Muse cell | Introduction
In his first academic position at the Department of Biology at the Technion-Israel Institute of Technology, he first determined the molar stoichiometry of the mitochondrial P450 system proteins using specific antibodies that he generated. He then set out to clone the cDNAs and the genes that code for these enzymes. His lab was the first to clone the cDNAs and the gene coding for adrenodoxin reductase - the first enzyme in the electron transfer chain of the mitochondrial P450 system. By sequence and structural analyses of adrenodoxin reductase, Israel identified its binding sites for the electron donor and acceptor coenzymes, NADPH and FAD.
Israel Hanukoglu | Steroid hormone synthesis
DNA (deoxyribonucleic acid) was first found by Rosalind Franklin. She discovered that DNA exists in species by taking multiple x-rays until she found an "X" looking diagram. She did not actually know much about it other than it exists. She died a few years later due to a massive amount of exposure to x-rays. James Watson and Francis Cricket then used Rosalind's discovery and looked further into it. They discovered the structure of DNA. They were the first to know that DNA has a double helix after the analysis of the x-rays. With time, DNA fragments were discovered. They first studied DNA on very simplistic organisms.
Shredding (disassembling genomic data) | History
Charles Philippe Leblond, (February 5, 1910 – April 10, 2007) was a pioneer of cell biology and stem cell research and a Canadian former professor of anatomy. Leblond is notable for developing autoradiography and his work showing how cells continuously renew themselves, regardless of age.
Charles Philippe Leblond | Introduction
Sazanov is known for the discovery of the first atomic structure of respiratory complex I, using X-ray crystallography and the bacterial enzyme as a model. It is an entry point into the electron transport chain, responsible for most of the energy production in the cell. The complex I structure revealed many unexpected and unique features of this extravagantly elaborate membrane protein assembly. Sazanov then went on to determine the first complete atomic structure of the even larger mammalian mitochondrial complex I, using new cryogenic electron microscopy methods. Sazanov research investigates the coupling mechanism of complex I using a combination of structural and biophysical techniques.
Leonid Sazanov | Career and research
Autophagy was first observed by Keith R. Porter and his student Thomas Ashford at the Rockefeller Institute. In January 1962 they reported an increased number of lysosomes in rat liver cells after the addition of glucagon, and that some displaced lysosomes towards the centre of the cell contained other cell organelles such as mitochondria. They called this autolysis after Christian de Duve and Alex B. Novikoff. However Porter and Ashford wrongly interpreted their data as lysosome formation (ignoring the pre-existing organelles). Lysosomes could not be cell organelles, but part of cytoplasm such as mitochondria, and that hydrolytic enzymes were produced by microbodies.
Autophagy | History
The key properties of a stem cell were first defined by Ernest McCulloch and James Till at the University of Toronto in the early 1960s. They discovered the blood-forming stem cell, the hematopoietic stem cell (HSC), through their pioneering work in mice. McCulloch and Till began a series of experiments in which bone marrow cells were injected into irradiated mice. They observed lumps in the spleens of the mice that were linearly proportional to the number of bone marrow cells injected. They hypothesized that each lump (colony) was a clone arising from a single marrow cell (stem cell). In subsequent work, McCulloch and Till, joined by graduate student Andy Becker and senior scientist Lou Siminovitch, confirmed that each lump did in fact arise from a single cell.
Stem cell | History
Elaine Diacumakos (August 11, 1930 – June 11, 1984) was a cell biologist and head of the cytobiology laboratory at Rockefeller University. She developed the first techniques for removing and inserting material into and from cells.
Elaine Diacumakos | Introduction
In 1977, at the same laboratory at Yale University, this first neuronal phosphoprotein was purified and initially characterized by Tetsufumi Ueda and Nobel Prize winner Paul Greengard. Originally named Protein I, it was found as an endogenous substrate for cAMP-dependent protein kinase in the synaptic membrane of the rat brain and was the first collagenous protein to be described in the nervous system.
Synapsin I | Discovery
He is also interested in the signaling pathway controlled by cyclic adenosine monophosphate (cAMP). His group generated the first genetically encoded fluorescent cAMP probe, contributed to establishing the concept of cAMP microdomains and described the existence of an autonomous cAMP homeostatic mechanism within the matrix of mitochondria.
Tullio Pozzan | Career and research
Schatz played a leading role in elucidating the biogenesis of mitochondria and in discovering mitochondrial DNA. He recognized that this DNA encoded only a small number of mitochondrial proteins which was decisive for his further research on the import of proteins into the mitochondria and the degradation of proteins within these organelles. Schatz discovered a complex transport system that recognizes mitochondrial proteins made in the cytoplasm by specific signals attached to these proteins and then transfers them into the mitochondria. This system comprises two protein complexes, TOM and TIM, which are localized in the outer and inner mitochondrial membranes respectively.
Gottfried Schatz | Work
In 1983, Barbara McClintock, an American cytogeneticist and the first woman to receive an unshared Nobel Prize in Physiology or Medicine, received the Nobel Prize for observing that the chromosomes lacking end parts became "sticky" and hypothesized the existence of a special structure at the chromosome tip that would maintain chromosome stability.
Telomere | Discovery
In 1903, Nikolai K. Koltsov proposed that the shape of cells was determined by a network of tubules that he termed the cytoskeleton. The concept of a protein mosaic that dynamically coordinated cytoplasmic biochemistry was proposed by Rudolph Peters in 1929 while the term ("cytosquelette", in French) was first introduced by French embryologist Paul Wintrebert in 1931. When the cytoskeleton was first introduced, it was thought to be an uninteresting gel-like substance that helped organelles stay in place. Much research took place to try to understand the purpose of the cytoskeleton and its components. With the help of Stuart Hameroff and Roger Penrose, it was discovered that microtubules vibrate within neurons in the brain, suggesting that brain waves come from deeper microtubule vibrations.
Cytoskeleton | History
Leblond used autoradiography to introduce radioactive precursors of DNA and then examine the renewal and fate of cells of several basic tissue types. He demonstrated for the first time that most cells and tissues in the adult body undergo continued renewal. Using mathematical models and modern methods of quantitation, Leblond and his colleagues estimated with remarkable accuracy the turnover and mitotic rates of numerous cell types. He and his colleagues made fascinating discoveries that resulted in the introduction of "time dimension" to cells and tissues, opening the doors to the understanding of the cell cycle and to the identification of stem cells.
Charles Philippe Leblond | Studies on the <a href="Cell%20turnover">turnover</a> of cells
Devoted to medical research, he initially joined German institutes in Berlin. In 1929 he found an opportunity to join the Rockefeller Institute in New York. At Rockefeller University he made his most groundbreaking achievements in cell biology. In 1930 he developed the technique of cell fractionation, by which he discovered the agent of the Rous sarcoma, components of cell organelles such as mitochondrion, chloroplast, endoplasmic reticulum, Golgi apparatus, ribosome and lysosome. He was the first to employ the electron microscope in the field of biology. In 1945 he published the first detailed structure of cell. His collective works established the complex functional and structural properties of cells.
Albert Claude | Introduction
Historians of science now realize his early discovery, and his Fermi Award recognized this discovery.
Alexander Hollaender | Introduction
At the Max-Planck-Institut in Berlin, Barbieri obtained the largest microcrystals of eukaryotic ribosomes that have ever appeared in the scientific literature. At the Medical Research Council in Cambridge, and at the National Institutes of Health in Bethesda, he developed mathematical models for the reconstruction of structures from incomplete information and has shown that a convergent increase in complexity is possible if the reconstructions are performed with iterative methods that make use of memories and codes . He has proposed that the existence of organic codes is revealed by the presence of adaptors and has shown that such codes exist in signal transduction, in the cytoskeleton and in cell compartments.
Marcello Barbieri | Research
Numerous descriptions of cell division were made during 18th and 19th centuries, with various degrees of accuracy. In 1835, the German botanist Hugo von Mohl, described cell division in the green alga "Cladophora glomerata", stating that multiplication of cells occurs through cell division. In 1838, Matthias Jakob Schleiden affirmed that the formation of new cells "in their interior" was a general law for cell multiplication in plants, a view later rejected in favour of Mohl model, due to contributions of Robert Remak and others. In animal cells, cell division with mitosis was discovered in frog, rabbit, and cat cornea cells in 1873 and described for the first time by the Polish histologist Wacław Mayzel in 1875.
Mitosis | Discovery
On October 6, Edward George Bowen, a key developer of RDF at the Telecommunications Research Establishment (TRE) and a member of the mission, demonstrated the magnetron, producing some 15,000 watts (15 kW) of power at 3 GHz, i.e. a wavelength of 10cm.
MIT Radiation Laboratory | Formation
When Leblond and his colleagues used 14C-bicarbonate, and then 35S-labeled amino acids to investigate protein synthesis, they were astonished to find that virtually all cells in the body incorporated label. This led them to the conclusion, considered heretical at the time, that all cells continually synthesized proteins. This was among the first evidence to replace the Specificity concept with the idea that most cells are multipotential in their functions. It is of interest that autoradiographic studies by Leblond during this period also settled a controversy regarding the cellular site of synthesis of ribonucleic acid. Using radiolabeled cytidine in some forty cell types, he and his colleagues were the first to demonstrate decisively that RNA is continuously synthesized in the nucleus and then migrates to the cytoplasm.
Charles Philippe Leblond | Continuous Protein Synthesis in living Cells
Van der Giezen has published extensively in his field of research and made over 50 contributions as external seminars and lectures at international scientific meetings. Van der Giezen investigates adaptations of microbial eukaryotes to life under anoxia, or low oxygen. He discovered mitochondrial remnants (mitosomes) in the human intestinal parasite "Giardia intestinalis", an organism until then considered to be one of the most primitive eukaryotes. This discovery called for re-assessment of the evolution of mitochondria. Van der Giezen's research has demonstrated that several unusual organelles are in fact mitochondria. More recently, he has conducted large dataset analyses of microbial eukaryotes.
Mark van der Giezen | Scientific achievements
Vestweber has worked in three different areas of molecular biology. During his studies for his PhD in the laboratory of Rolf Kemler he investigated the molecular mechanisms of cell recognition and cell adhesion between epithelial cells and during the development of the mouse preimplantation embryo, working on the adhesion molecule E-cadherin (uvomorulin). In the course of his postdoctoral work in the group of Gottfried Schatz at the Biocenter in Basel, Vestweber studied the biogenesis of mitochondria and found the first membrane component (today known as TOM 40) of the mitochondrial import machinery for the transport of proteins into this organelle.
Dietmar Vestweber | Research
However, most scientists disputed his discovery as nothing but a staining artefact. Their microscopes were not powerful enough to identify the organelles. By the 1930s, Golgi's description was largely rejected. It was only firmly established after 50 years of its discovery, when electron microscopes were developed.
Camillo Golgi | Cell organelle
In 1959, he became chair of Microbiology at the Massachusetts Institute of Technology (MIT). At MIT, he switched his research focus from phages to cell membranes and bacteriocins. While on sabbatical in 1963 to study at the Institut Pasteur in Paris, he found that bacteriocins impair the function of cell membranes. Returning to MIT, his lab discovered that bacteriocins achieve this impairment by forming holes in the cell membrane, allowing ions to flow through and destroy the electrochemical gradient of cells. In 1972, he became chair of The Center for Cancer Research at MIT. The department he established included future Nobel Prize winners David Baltimore, Susumu Tonegawa, Phillip Allen Sharp and H.
Salvador Luria | Later work
This cytokine was co-discovered by Maureen Howard and William E. Paul as well as by Ellen Vitetta and her research group in 1982. The nucleotide sequence for human IL-4 was isolated four years later confirming its similarity to a mouse protein called B-cell stimulatory factor-1 (BCSF-1).
Interleukin 4 | Discovery
His laboratory discovered the first overlapping genes in bacterial viruses, the stimulation of a set of bacterial proteins synthesis upon virus infection, and showed directly, by electron microscopy, that a bacterial protein (IHF) bends DNA. He also worked on the factors that control immunoglobulin gene expression, the structure of the genes and their rearrangement during B-cell differentiation. These experiments led to the discovery of the mutational potential of retrovirus sequences in the mouse genome. Looking back on his life's work, he surmises that his scientific papers will become obsolete and his novels outdated, but that his cellos will improve with time.
Helios Murialdo | Research
This was further proved with the finding that mitochondria and chloroplasts had a separate genome from the host genome, but had lost the ability to live outside of the host.
Reductive evolution | History
When diagramed, the resulting structure looks like the letter D. The D-loop was first discovered in 1971 when researchers noticed that many DNA in the mitochondria they were examining under microscope contained a short segment that was tripled stranded.
D-loop replication | Introduction
The mitochondrion (, plural mitochondria) is a semi autonomous double-membrane-bound organelle found in most eukaryotic organisms. Some cells in some multicellular organisms may, however, lack mitochondria (for example, mature mammalian red blood cells). A number of unicellular organisms, such as microsporidia, parabasalids, and diplomonads, have also reduced or transformed their mitochondria into other structures. To date, only one eukaryote, "Monocercomonoides", is known to have completely lost its mitochondria, and one multicellular organism, "Henneguya salminicola", is known to have retained mitochondrion-related organelles in association with a complete loss of their mitochondrial genome. The word mitochondrion comes from the Greek , , "thread", and , , "granule" or "grain-like".
Mitochondrion | Introduction
Gopinath Kartha (26 January 1927 – 18 June 1984) was a prominent crystallographer of Indian origin. In 1967, he determined the molecular structure of the enzyme ribonuclease. This was the first protein structure elucidated and published in the United States.
Gopinath Kartha | Introduction
Also in 1998, Reski and coworkers generated a knockout moss by deleting an "ftsZ" gene and thus identified the first gene essential in the division of an organelle in any eukaryote. Based on the results of further research on the ftsZ-gene family, Ralf Reski coined the term "plastoskeleton", analogous to the term "cytoskeleton", in 2000 and presented a new concept in cell biology of how chloroplasts, the green cell organelles of plants, change shape and divide.
Ralf Reski | Research
De Duve was skeptical of referring to the new-found enzymes as microbodies because, as he noted, "too little is known of their enzyme complement and of their role in the physiology of the liver cells to substantiate a proposal at the present time". He suggested that these enzymes belonged to the same cell organelle, but one different from previously known organelles. But, as strong evidences were still lacking, he did not publish his hypothesis. In 1955 his team demonstrated similar cell fractions with same biochemical properties from the ciliated protozoan "Tetrahymena pyriformis"; thus, it was indicated that the particles were undescribed cell organelles unrelated to mitochondria.
Christian de Duve | Discovery of peroxisome
Hidvegi's first publications were about the theories of the origins of life, and the elaboration of a plausible mechanism for the biogenesis and evolution of biomembranes. He worked out the metabolic map as well as the reaction kinetics of a theoretical first living cell.
Máté Hidvégi | Early academic life
Monocercomonoides is a genus of flagellate Excavata belonging to the order Oxymonadida. It was established by Bernard V. Travis and was first described as those with "polymastiginid flagellates having three anterior flagella and a trailing one originating at a single basal granule located in front of the anteriorly positioned nucleus, and a more or less well-defined axostyle". It is the first eukaryotic genus to be found to completely lack mitochondria, and all hallmark proteins responsible for mitochondrial function. Data suggests that the absence of mitochondria is not an ancestral feature, but rather due to secondary loss. "Monocercomonoides "sp. was found to obtain energy through an enzymatic action of nutrients absorbed from the environment.
Monocercomonoides | Introduction
These spheres of cells that Reynolds and Weiss discovered in 1992 were the first neurosphere formations created and analyzed.
Neurosphere | Reynolds and Weiss
The Shine-Dalgarno sequence, of the prokaryotic RBS, was discovered by John Shine and Lynne Dalgarno in 1975. The Kozak consensus sequence was first identified by Marilyn Kozak in 1984 while she was in the Department of Biological Sciences at the University of Pittsburgh.
Ribosome-binding site | History
In his 1981 Ph.D. thesis, Youvan found inhibitors (hypermodified nucleosides) of retroviral reverse transcriptase present in ribosomal RNA. In a 1984 publication with John E. Hearst, and in collaboration with Barry L. Marrs, Youvan published the nucleotide and deduced protein sequence for the photosynthetic reaction center – the proteins that convert light to chemical energy in photosynthetic organisms. This work correctly predicted the secondary structure of the 11 transmembrane helices of the reaction center as confirmed by X-ray crystallography. In 1987 Youvan and E. Bylina constructed the first site-directed mutants of bacterial reaction centers. Later collaborative work with ultra-fast laser laboratories helped yield evidence for a vibrational coherence in the sub-picosecond processes of photosynthetic charge separation.
Douglas Youvan | Research focus
Toni Gabaldón and Martijn Huynen (2003) reconstructed the proteome (the entire set of proteins expressed by a genome) and corresponding metabolism of the proto-mitochondrion by comparing extant alpha-proteobacterial and eukaryotic genomes. They concluded that this organism was an aerobic alpha-proteobacterium catabolyzing lipids, glycerol and other compounds provided by the host. At least 630 gene families derived from this organism can still be found in the 9 eukaryotic genomes analyzed in the study.
Proto-mitochondrion | Metabolism
He named the granules "bioblasts", and explained them as the elementary living units, having metabolic and genetic autonomy, in his 1890 book ""Die Elementarorganismen"" ("The Elementary Organism"). His explanation drew much skepticism and harsh criticism. Altmann's granules are now believed to be mitochondria.
Richard Altmann | Introduction
The ability of these bacteria to conduct respiration in host cells that had relied on glycolysis and fermentation would have provided a considerable evolutionary advantage. This symbiotic relationship probably developed 1.7 to 2 billion years ago. A few groups of unicellular eukaryotes have only vestigial mitochondria or derived structures: the microsporidians, metamonads, and archamoebae. These groups appear as the most primitive eukaryotes on phylogenetic trees constructed using rRNA information, which once suggested that they appeared before the origin of mitochondria. However, this is now known to be an artifact of long-branch attraction—they are derived groups and retain genes or organelles derived from mitochondria (e.
Mitochondrion | Origin and evolution
Hodgkin and Huxley were awarded jointly the Nobel Prize for this work in 1963. The formulas detailing axonal conductance were extended to vertebrates in the Frankenhaeuser–Huxley equations. Louis-Antoine Ranvier was the first to describe the gaps or nodes found on axons and for this contribution these axonal features are now commonly referred to as the Nodes of Ranvier. Santiago Ramón y Cajal, a Spanish anatomist, proposed that axons were the output components of neurons. He also proposed that neurons were discrete cells that communicated with each other via specialized junctions, or spaces, between cells, now known as a synapse. Ramón y Cajal improved a silver staining process known as Golgi's method, which had been developed by his rival, Camillo Golgi.
Dendrite | History
A mitochondrion contains DNA, which is organized as several copies of a single, usually circular chromosome. This mitochondrial chromosome contains genes for redox proteins, such as those of the respiratory chain. The CoRR hypothesis proposes that this co-location is required for redox regulation. The mitochondrial genome codes for some RNAs of ribosomes, and the 22 tRNAs necessary for the translation of mRNAs into protein. The circular structure is also found in prokaryotes. The proto-mitochondrion was probably closely related to "Rickettsia". However, the exact relationship of the ancestor of mitochondria to the alphaproteobacteria and whether the mitochondrion was formed at the same time or after the nucleus, remains controversial.
Mitochondrion | Origin and evolution
They were discovered in 1980 by Novick and Schekman, of the Department of Biochemistry, University of California, Berkeley.
Berkeley body | Introduction
He was the first person to describe siderocytes and sideroblasts, atypical nucleated erythrocytes with granules of iron accumulated in perinuclear mitochondria. This he reported in the journal "Nature". The Grüneberg ganglion, an olfactory ganglion in rodents, was first described by Hans Grueneberg in 1973.
Hans Grüneberg | Introduction
Margulis was also the co-developer of the Gaia hypothesis with the British chemist James Lovelock, proposing that the Earth functions as a single self-regulating system, and was the principal defender and promulgator of the five kingdom classification of Robert Whittaker. Throughout her career, Margulis' work could arouse intense objection (one grant application elicited the response, "Your research is crap, do not bother to apply again"), and her formative paper, "On the Origin of Mitosing Cells", appeared in 1967 after being rejected by about fifteen journals. Still a junior faculty member at Boston University at the time, her theory that cell organelles such as mitochondria and chloroplasts were once independent bacteria was largely ignored for another decade, becoming widely accepted only after it was powerfully substantiated through genetic evidence.
Lynn Margulis | Introduction
While at MIT Levinthal made significant discoveries in molecular genetics relating to the mechanisms of DNA replication, the relationship between genes and proteins, and the nature of messenger RNA. At Columbia Levinthal applied computers to the 3-dimensional imaging of biological structures such as proteins. He is considered the father of computer graphical display of protein structure.
Cyrus Levinthal | Research
("The New York Times" subsequently ran a longer article on 12 June 1953). The Cambridge University undergraduate newspaper "Varsity" also ran its own short article on the discovery on Saturday 30 May 1953. Bragg's original announcement of the discovery at a Solvay Conference on proteins in Belgium on 8 April 1953 went unreported by the British press. Sydney Brenner, Jack Dunitz, Dorothy Hodgkin, Leslie Orgel, and Beryl M. Oughton, were some of the first people in April 1953 to see the model of the structure of DNA, constructed by Crick and Watson; at the time they were working at the University of Oxford's Chemistry Department.
Cavendish Laboratory | Biology
Prior to James Watson and Francis Crick's landmark paper that detailed the structure of DNA from Rosalind Franklin's X-ray crystallography image, there were several historical scientists that also contributed to its discovery. Friedrich Miescher, a Swiss physician, who, in 1869, was first to isolate and identify nucleic substance from the nuclei of white blood cells he later called “nuclein”, paving the way for the discovery of DNA. Following Mieschers work, was the German biochemist, Albrecht Kossel, who, in 1878, isolated the non-protein components of “nuclein”, and discovered the five nucleobases present in nucleic acids: adenine, cytosine, guanine, thymine and uracil.
Ribonucleotide | History
They discovered that the "omega" intron was present in other yeast species collected in Harvard. Following the sequencing of several other introns, François Michel discovered that these introns could be folded into stem-loops whose structures (if not their sequences) were conserved. This suggested that they could be directly involved in the splicing mechanism by defining exon-intron junctions. In addition, they discovered that two different intronic structures existed, defining what they called group I and group II introns, a nomenclature still in use today. They published their models of intron folding in "Biochimie" in 1982 and this article quickly became a reference for researchers in the field.
Bernard Dujon | The early years : discovery of the first homing endonuclease
He uncovered several molecular cell motors, including some that help certain white blood cells to move. He also elucidated how actin and myosin create movement in non-muscle cells. In 1950, Taylor, together with Gary Borisy who was a graduate student in Taylor's lab, discovered the protein that is the building block of microtubules, although the name of that protein, tubulin, was not coined until 1968. In 1967 Taylor found that the action of colchicine binding to cells could be modeled by a single kind of binding sites, perhaps showing that a unique target might exist. Taylor spends his summers in Woods Hole.Research Center in Massachusetts.
Edwin W. Taylor | Introduction
Ernest Armstrong McCulloch, (27 April 1926 – 20 January 2011) was a University of Toronto cellular biologist, best known for demonstrating – with James Till – the existence of stem cells.
Ernest McCulloch | Introduction
Bergeron pioneered in Quebec and Canada, he elucidated the major resident proteins of the secretory pathway common to all cells. This led to the discovery of several proteins characterized for the first time involved in organ biogenesis and disease.
John J. M. Bergeron | Research and scientific career
The cell nucleus was discovered by Robert Brown in 1831. Demonstration of the cellular composition of all organisms, with each cell possessing all the characteristics of life, is attributed to the combined efforts of botanist Matthias Schleiden and zoologist Theodor Schwann (1810–1882) in the early 19th century although Moldenhawer had already shown that plants were wholly cellular with each cell having its own wall and Julius von Sachs had shown the continuity protoplasm between cell walls. From 1870 to 1880 it became clear that cell nuclei are never formed anew but always derived from the substance of another nucleus. In 1882 Flemming observed the longitudinal splitting of chromosomes in the dividing nucleus and concluded that each daughter nucleus received half of each of the chromosomes of the mother nucleus: then by the early 20th century it was found that the number of chromosomes in a given species is constant.
History of botany | Cytology
Musacchio approached structural biology during his Ph.D., contributing to the determination of the first crystallographic structures of the SH3 and PH domains. During his post-doctoral training, he was involved in the determination of the clathrin triskelion structure, one of the first studies combining X-ray crystallography and electron microscopy. As an independent scientist, his interests focused on the understanding of the molecular basis of mitosis, with emphasis on the spindle assembly checkpoint. Since the early days, Musacchio's lab adopted a multi-disciplinary approach merging structural biology, biochemistry and cellular biology, this way gaining comprehensive views on protein functions in living cells. He is best known for his work on Mad1/Mad2 complexes, which led to the formulation of the "template model", and for his contributions to the understanding of the role of the kinase Aurora B, Mps1 and Haspin in mitosis.
Andrea Musacchio | Research
Victor R. Ambros (born 1953, Hanover, New Hampshire) is an American developmental biologist who discovered the first known microRNA (miRNA). He is a professor at the University of Massachusetts Medical School in Worcester, Massachusetts.
Victor Ambros | Introduction