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Torbjörn Caspersson
Torbjörn Oskar Caspersson (15 October 1910 – 7 December 1997) was a Sweden, Swedish cell biology, cytologist and geneticist. He was born in Motala and attended the Stockholm University, where he studied medicine and biophysics. Contributions Caspersson made several key contributions to biology. * 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 (biology), cell with an ultraviolet microscope to determine the nucleic acid content of cellular structures such as the cell nucleus, 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 in cells and published the work in 1939, where he independent of Jean Brachet, working out the same problem using a different technique, found that ce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Motala
Motala () is a Urban areas in Sweden, locality and the seat of Motala Municipality, Östergötland County, Sweden with a municipal population of 43,717 inhabitants in 2024. 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 Christina of Sweden, Kristina had a summer residence built at the spa resort of Medevi, 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 ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ultraviolet
Ultraviolet radiation, also known as simply UV, is electromagnetic radiation of wavelengths of 10–400 nanometers, 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, Cherenkov radiation, and specialized lights, such as mercury-vapor lamps, tanning lamps, and black lights. The photons of ultraviolet have greater energy than those of visible light, from about 3.1 to 12 electron volts, around the minimum energy required to ionize atoms. Although long-wavelength ultraviolet is not considered an ionizing radiation because its photons lack sufficient energy, it can induce chemical reactions and cause many substances to glow or fluoresce. Many practical applications, including chemical and biological effects, are derived from the way that UV radiation can interact with organic molecules. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Y Chromosome
The Y chromosome is one of two sex chromosomes in therian mammals and other organisms. Along with the X chromosome, it is part of the XY sex-determination system, in which the Y is the sex-determining chromosome because the presence of the Y chromosome causes offspring produced in sexual reproduction to be of male sex. In mammals, the Y chromosome contains the SRY gene, which triggers development of male gonads. The Y chromosome is passed only from male parents to male offspring. Overview Discovery The Y chromosome was identified as a sex-determining chromosome by Nettie Stevens at Bryn Mawr College in 1905 during a study of the mealworm ''Tenebrio molitor''. Edmund Beecher Wilson independently discovered the same mechanisms the same year, working with Hemiptera. Stevens proposed that chromosomes always existed in pairs and that the smaller chromosome (now labelled "Y") was the pair of the X chromosome discovered in 1890 by Hermann Henking. She realized that th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
X Chromosome
The X chromosome is one of the two sex chromosomes in many organisms, including mammals, 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 the object and consequently named it ''X element'', which later became X chromosome after it was established that it w ... [...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 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 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 XYY, XXY, XXX, XXXX, XXXXX or XXYY, among other irregular combinations, are known to occur and usually cause developmental abnormalities. Autosomes still contain sexual determination genes even though they are not sex chromosomes. For example, the SRY gene on the Y chromos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromosome
A chromosome is a package of DNA containing part or all of the genetic material of an organism. In most chromosomes, the very long thin DNA fibers are coated with nucleosome-forming packaging proteins; in eukaryotic cells, the most important of these proteins are the histones. Aided by chaperone proteins, the histones bind to and condense the DNA molecule to maintain its integrity. These eukaryotic chromosomes display a complex three-dimensional structure that has a significant role in transcriptional regulation. Normally, chromosomes are 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 stage occurs, each chromosome is duplicated ( S phase), and the two copies are joined by a centromere—resulting in either an X-shaped structure if the centromere is located equatorially, or a two-armed structure if the centromere is located distally; the jo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lore Zech
Lore Zech (24 September 1923 – 13 March 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, Sw ... [...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 residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metabolic reactions, DNA replication, Cell signaling, responding to stimuli, providing Cytoskeleton, structure to cells and Fibrous protein, organisms, and Intracellular transport, transporting molecules from one location to another. Proteins differ from one another primarily in their sequence of amino acids, which is dictated by the Nucleic acid sequence, nucleotide sequence of their genes, and which usually results in protein folding into a specific Protein structure, 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 pep ... [...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, an eminent embryologist. He was educated at L'École alsacienne in Paris and the . He studied medicine at the ('Free University of Brussels', the institution operating between 1834 and 1969), 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 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. At the same time as Torbjörn Caspersson he independently showed that RNA plays an active role in protei ... [...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 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 * Jack (hero), an archetypal Cornish and English hero and stock character Animals and plants Fish *Carangidae generally, including: **Almaco jack **Amberjack ** Bar jack ** Black jack (fish) ** Crevalle jack **Giant treval ... [...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. This reaction is also specific to DNA since RNA is characterized by a ribose sugar, instead of deoxyribose, preventing acid hydrolysis. This impedes purine detachment and thus do not allow the staining. The Feulgen reaction is a semi-quantitative technique. If the only aldehydes remaining in the cell are those p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
