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Torbjörn Caspersson
Torbjörn Oskar Caspersson (15 October 1910 – 7 December 1997) was a Swedish cytologist and geneticist. He was born in Motala and attended the University of Stockholm, where he studied medicine and biophysics. Contributions Caspersson made several key contributions to biology. * In the 1934 he and Einar Hammarsten showed that DNA was a polymer. Previous theories suggested that each molecule was only ten nucleotides long. * He provided William Astbury with well prepared samples of DNA for Astbury's pioneering structural measurements. * In 1936, in his doctoral thesis in chemistry, presented at the Karolinska Institute in Stockholm, he first studied genetic material inside a cell with an ultraviolet microscope to determine the nucleic acid content of cellular structures such as the nucleus and nucleolus using the Feulgen reaction to stain the DNA. * He worked with Jack Schultz in Stockholm from 1937 to 1939 on protein synthesis is cells and published the work in 1939, where he ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Motala
Motala () is a locality and the seat of Motala Municipality, Östergötland County, Sweden with 29,823 inhabitants (41,956 in the entire municipality) in 2010. It is the third largest city of Östergötland, following Linköping and Norrköping. Motala is situated on the eastern shore of Lake Vättern and is regarded as the main centre of both the Göta Canal and the surrounding lake region. History Motala Church dates from the 13th century. For several centuries, Motala remained a small village, mainly regarded as a stopping post on the road to the nearby town of Vadstena, one of the cultural centres of medieval Sweden. However, King Gustav Vasa had a manor house built at Motala and later Queen Kristina had a summer residence built at the spa resort of Medevi, 20 km north of the town. When the Göta Canal was built in the early 19th century, Motala became an important town for the trade on the canal. The builder of the canal, Baltzar von Platen, has his grave beside it ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ultraviolet
Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nanometer, nm (with a corresponding frequency around 30 Hertz, PHz) to 400 nm (750 Hertz, THz), shorter than that of visible light, but longer than X-rays. UV radiation is present in sunlight, and constitutes about 10% of the total electromagnetic radiation output from the Sun. It is also produced by electric arcs and specialized lights, such as mercury-vapor lamps, tanning lamps, and black lights. Although long-wavelength ultraviolet is not considered an ionizing radiation because its photons lack the energy to ionization, ionize atoms, it can cause chemical reactions and causes many substances to glow or fluorescence, fluoresce. Consequently, the chemical and biological effects of UV are greater than simple heating effects, and many practical applications of UV radiation derive from its interactions with organic molecules. Short-wave ultraviolet light damages DNA and sterilizes surf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Y Chromosome
The Y chromosome is one of two sex chromosomes (allosomes) in therian mammals, including humans, and many other animals. The other is the X chromosome. Y is normally the sex-determining chromosome in many species, since it is the presence or absence of Y that determines the male or female sex of offspring produced in sexual reproduction. In mammals, the Y chromosome contains the gene SRY, which triggers male development. The DNA in the human Y chromosome is composed of about 59 million base pairs, making it similar in size to chromosome 19. The Y chromosome is passed only from father to son. With a 30% difference between humans and chimpanzees, the Y chromosome is one of the fastest-evolving parts of the human genome. The human Y chromosome carries an estimated 100–200 genes, with between 45 and 73 of these being protein-coding. All single-copy Y-linked genes are hemizygous (present on only one chromosome) except in cases of aneuploidy such as XYY syndrome or XXYY syndrome. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
X Chromosome
The X chromosome is one of the two sex-determining chromosomes (allosomes) in many organisms, including mammals (the other is the Y chromosome), and is found in both males and females. It is a part of the XY sex-determination system and XO sex-determination system. The X chromosome was named for its unique properties by early researchers, which resulted in the naming of its counterpart Y chromosome, for the next letter in the alphabet, following its subsequent discovery. Discovery It was first noted that the X chromosome was special in 1890 by Hermann Henking in Leipzig. Henking was studying the testicles of ''Pyrrhocoris'' and noticed that one chromosome did not take part in meiosis. Chromosomes are so named because of their ability to take up staining (''chroma'' in Greek means ''color''). Although the X chromosome could be stained just as well as the others, Henking was unsure whether it was a different class of object and consequently named it ''X element'', which later be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Autosome
An autosome is any chromosome that is not a sex chromosome. The members of an autosome pair in a diploid cell have the same morphology, unlike those in allosome, allosomal (sex chromosome) pairs, which may have different structures. The DNA in autosomes is collectively known as atDNA or auDNA. For example, humans have a diploid human genome, genome that usually contains 22 pairs of autosomes and one allosome pair (46 chromosomes total). The autosome pairs are labeled with numbers (1–22 in humans) roughly in order of their sizes in base pairs, while allosomes are labelled with their letters. By contrast, the allosome pair consists of two X chromosomes in females or one X and one Y chromosome in males. Unusual combinations of XYY syndrome, XYY, Klinefelter syndrome, XXY, Triple X syndrome, XXX, XXXX syndrome, XXXX, XXXXX syndrome, XXXXX or XXYY syndrome, XXYY, among Aneuploidy, other Salome combinations, are known to occur and usually cause developmental abnormalities. Autosomes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromosome
A chromosome is a long DNA molecule with part or all of the genetic material of an organism. In most chromosomes the very long thin DNA fibers are coated with packaging proteins; in eukaryotic cells the most important of these proteins are the histones. These proteins, aided by chaperone proteins, bind to and condense the DNA molecule to maintain its integrity. These chromosomes display a complex three-dimensional structure, which plays a significant role in transcriptional regulation. Chromosomes are normally visible under a light microscope only during the metaphase of cell division (where all chromosomes are aligned in the center of the cell in their condensed form). Before this happens, each chromosome is duplicated ( S phase), and both copies are joined by a centromere, resulting either in an X-shaped structure (pictured above), if the centromere is located equatorially, or a two-arm structure, if the centromere is located distally. The joined copies are now called si ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lore Zech
Lore Zech (1923—2013) was a German geneticist and cytogenetics researcher who made major contributions to the field of cytogenetics. Her research and discoveries paved the way for the identification of anomalies in chromosomes of diseased cells and eventually for many treatments and therapies for these diseases. Her notable works include her discovery of Q-banding and her research on leukemia and lymphoma. Biography Zech was born in 1923 in Gütersloh, Germany. Her grandmother raised her in Sauerland as Zech's parents died when she was 4 years old. From 1944 till after World War II, Zech studied medicine at the University of Marburg in Germany. Having left the medical field of study, Lore then picked up biology, chemistry, and physics at the University of Bonn and completed her doctoral thesis at the Max Planck Institute in Tübingen. From 1953 till 1989, she worked at the Institute of Cell Research and Genetics at the Karolinska Institute in Stockholm, Sweden where most of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Karolinska Institute
The Karolinska Institute (KI; sv, Karolinska Institutet; sometimes known as the (Royal) Caroline Institute in English) is a research-led medical university in Solna within the Stockholm urban area of Sweden. The Karolinska Institute is consistently ranked amongst the world's best medical schools, ranking 6th worldwide for medicine in 2021. The Nobel Assembly at the Karolinska Institute awards the Nobel Prize in Physiology or Medicine. The assembly consists of fifty professors from various medical disciplines at the university. The current rector of Karolinska Institute is Ole Petter Ottersen, who took office in August 2017. The Karolinska Institute was founded in 1810 on the island of Kungsholmen on the west side of Stockholm; the main campus was relocated decades later to Solna, just outside Stockholm. A second campus was established more recently in Flemingsberg, Huddinge, south of Stockholm. The Karolinska Institute is Sweden's third oldest medical school, after Uppsala ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, responding to stimuli, providing structure to cells and organisms, and transporting molecules from one location to another. Proteins differ from one another primarily in their sequence of amino acids, which is dictated by the nucleotide sequence of their genes, and which usually results in protein folding into a specific 3D structure that determines its activity. A linear chain of amino acid residues is called a polypeptide. A protein contains at least one long polypeptide. Short polypeptides, containing less than 20–30 residues, are rarely considered to be proteins and are commonly called peptides. The individual amino acid residues are bonded together by peptide bonds and adjacent amino acid residues. The sequence of amino acid residue ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jean Brachet
Jean Louis Auguste Brachet (19 March 1909 – 10 August 1988) was a Belgian biochemist who made a key contribution in understanding the role of RNA. Life Brachet was born in Etterbeek near Brussels in Belgium, the son of Albert Brachet, embryologist. He was educated at L'Ecole Alsacienne in Paris then studied medicine at the Université Libre de Bruxelles graduating in 1934. He then worked at the University of Cambridge and at Princeton University and at several institutes of marine biological research. Brachet was appointed Professor of Animal Morphology and General Biology at the Université Libre de Bruxelles and Research Director of the International Laboratory for Genetics and Biophysics in Naples. In 1933 Brachet was able to show that DNA was found in chromosomes and that RNA was present in the cytoplasm of all cells.Sapp J., ''Jean Brachet, L'Hérédité Générale and the Origins of Molecular Embryology'', History and philosophy of the life sciences (Hist. phi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jack Schultz
Jack may refer to: Places * Jack, Alabama, US, an unincorporated community * Jack, Missouri, US, an unincorporated community * Jack County, Texas, a county in Texas, USA People and fictional characters * Jack (given name), a male given name, including a list of people and fictional characters with the name * Jack (surname), including a list of people with the surname * Jack (Tekken), multiple fictional characters in the fighting game series ''Tekken'' * Jack the Ripper, an unidentified British serial killer active in 1888 * Wolfman Jack (1938–1995), a stage name of American disk jockey Robert Weston Smith * New Jack, a stage name of Jerome Young (1963-2021), an American professional wrestler * Spring-heeled Jack, a creature in Victorian-era English folklore Animals and plants Fish * Carangidae generally, including: **Almaco jack ** Amberjack **Bar jack **Black jack (fish) ** Crevalle jack **Giant trevally or ronin jack **Jack mackerel **Leather jack ** Yellow jack *Coh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Feulgen Reaction
Feulgen stain is a staining technique discovered by Robert Feulgen and used in histology to identify chromosomal material or DNA in cell specimens. It is darkly stained. It depends on acid hydrolysis of DNA, therefore fixating agents using strong acids should be avoided. The specimen is subjected to warm (60 °C) hydrochloric acid, then to Schiff reagent. In the past, a sulfite rinse followed, but this is now considered unnecessary. Optionally, the sample can be counterstained with Light Green SF yellowish. Finally, it is dehydrated with ethanol, cleared with xylene, and mounted in a resinous medium. DNA should be stained red. The background, if counterstained, is green. The Feulgen reaction is a semi-quantitative technique. If the only aldehydes remaining in the cell are those produced from the hydrolysis of DNA, then the technique is quantitative for DNA. It is possible to use an instrument known as a microdensitometer or microspectrophotometer to actually measure the inten ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
