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Adolf Mayer
Adolf Eduard Mayer (9 August 184325 December 1942) was a German agricultural chemist whose work on tobacco mosaic disease played an important role in the discovery of tobacco mosaic virus and viruses in general. Mayer was born in 1843 into the family of a high school teacher in Oldenburg. His mother was a daughter of renowned German chemist Leopold Gmelin. From 1860 to 1862 he studied mathematics and chemistry at the Karlsruhe Institute of Technology. In 1862 he enrolled at the University of Heidelberg, where in 1864 he graduated summa cum laude with a Ph.D. in chemistry, physics, and mathematics. In 1879, while Mayer held the position of the director of the Agricultural Experiment Station at Wageningen in the Netherlands, he was asked by Dutch farmers to study a peculiar disease affecting the tobacco plant. Mayer published a paper in 1886 on the disease, which he named "mosaic disease of tobacco", and described its symptoms in detail. He demonstrated that the disease can ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oldenburg (city)
Oldenburg () is an independent city in the state of Lower Saxony, Germany. The city is officially named Oldenburg (Oldb) (''Oldenburg in Oldenburg'') to distinguish from Oldenburg in Holstein. During the French annexation (1811–1813) in the wake of the Napoleonic war against Britain, it was also known as ''Le Vieux-Bourg'' in French. The city is at the rivers Hunte and Haaren, in the northwestern region between the cities of Bremen in the east and Groningen (Netherlands) in the west. It has a population of 170,000 (November 2019). Oldenburg is part of the Bremen/Oldenburg Metropolitan Region, with 2.37 million people. The city is the place of origin of the House of Oldenburg. Before the end of the German Empire (1918), it was the administrative centre and residence of the monarchs of Oldenburg. History Archaeological finds point to a settlement dating back to the 8th century. The first documentary evidence, in 1108, referenced ''Aldenburg'' in connection with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wageningen
Wageningen () is a municipality and a historic city in the central Netherlands, in the province of Gelderland. It is famous for Wageningen University, which specialises in life sciences. The municipality had a population of in , of which many thousands are students from over 150 countries. Demograpics Inhabitants by nationality 71,68% is Dutch, 28,32% has a migration background. Geography Wageningen is situated on the north bank of the Nederrijn (the Dutch portion of the Lower Rhine) part of the Gelderse valley (Dutch: Gelderse Vallei) and the Veluwe, of which the southwest hill is called the ''Wageningse Berg''. Wageningen can be reached by car from highways A12 via the N781, A15 via the N233 and N225, and A50 via the N225, and from the Ede-Wageningen railway station via a 20-minute bus drive to the Wageningen central terminal (see below)., ''Topographic map of the municipality of Wageningen, July 2013 (click to enlarge)'' History The oldest known settlements in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
German Agronomists
German(s) may refer to: * Germany (of or related to) **Germania (historical use) * Germans, citizens of Germany, people of German ancestry, or native speakers of the German language ** For citizens of Germany, see also German nationality law **Germanic peoples (Roman times) * German language **any of the Germanic languages * German cuisine, traditional foods of Germany People * German (given name) * German (surname) * Germán, a Spanish name Places * German (parish), Isle of Man * German, Albania, or Gërmej * German, Bulgaria * German, Iran * German, North Macedonia * German, New York, U.S. * Agios Germanos, Greece Other uses * German (mythology), a South Slavic mythological being * Germans (band), a Canadian rock band * "German" (song), a 2019 song by No Money Enterprise * ''The German'', a 2008 short film * "The Germans", an episode of ''Fawlty Towers'' * ''The German'', a nickname for Congolese rebel André Kisase Ngandu See also * Germanic (other) * Ge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1942 Deaths
Year 194 ( CXCIV) was a common year starting on Tuesday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Septimius and Septimius (or, less frequently, year 947 '' Ab urbe condita''). The denomination 194 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years. Events By place Roman Empire * Emperor Septimius Severus and Decimus Clodius Septimius Albinus Caesar become Roman Consuls. * Battle of Issus: Septimius Severus marches with his army (12 legions) to Cilicia, and defeats Pescennius Niger, Roman governor of Syria. Pescennius retreats to Antioch, and is executed by Severus' troops. * Septimius Severus besieges Byzantium (194–196); the city walls suffer extensive damage. Asia * Battle of Yan Province: Warlords Cao Cao and Lü Bu fight for control over Yan Province; the battle lasts for ov ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1843 Births
Events January–March * January ** Serial publication of Charles Dickens's novel ''Martin Chuzzlewit'' begins in London; in the July chapters, he lands his hero in the United States. ** Edgar Allan Poe's short story "The Tell-Tale Heart" is published in a Boston magazine. ** The Quaker magazine '' The Friend'' is first published in London. * January 3 – The ''Illustrated Treatise on the Maritime Kingdoms'' (海國圖志, ''Hǎiguó Túzhì'') compiled by Wei Yuan and others, the first significant Chinese work on the West, is published in China. * January 6 – Antarctic explorer James Clark Ross discovers Snow Hill Island. * January 20 – Honório Hermeto Carneiro Leão, Marquis of Paraná, becomes ''de facto'' first prime minister of the Empire of Brazil. * February – Shaikh Ali bin Khalifa Al-Khalifa captures the fort and town of Riffa after the rival branch of the family fails to gain control of the Riffa Fort and flees to Manama. Shaikh Mohamed bin Ahmed is killed a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virology
Virology is the scientific study of biological viruses. It is a subfield of microbiology that focuses on their detection, structure, classification and evolution, their methods of infection and exploitation of host cells for reproduction, their interaction with host organism physiology and immunity, the diseases they cause, the techniques to isolate and culture them, and their use in research and therapy. The identification of the causative agent of tobacco mosaic disease (TMV) as a novel pathogen by Martinus Beijerinck (1898) is now acknowledged as being the official beginning of the field of virology as a discipline distinct from bacteriology. He realized the source was neither a bacterial nor a fungal infection, but something completely different. Beijerinck used the word "virus" to describe the mysterious agent in his 'contagium vivum fluidum' ('contagious living fluid'). Rosalind Franklin proposed the full structure of the tobacco mosaic virus in 1955. Virology ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dmitry Ivanovsky
Dmitri Iosifovich Ivanovsky (alternative spelling ''Dmitrii'' or ''Dmitry Iwanowski''; russian: Дми́трий Ио́сифович Ивано́вский; 28 October 1864 – 20 June 1920) was a Russian botanist, the co-discoverer of :viruses (1892) and one of the founders of virology. Life Ivanovsky was born in the village of Nizy, Gdov Uyezd. He studied at the University of Saint Petersburg under Andrei Famintsyn in 1887, when he was sent to Ukraine and Bessarabia to investigate a tobacco disease causing great damage to plantations located there at the time. Three years later, he was assigned to look into a similar disease occurrence of tobacco plants, this time raging in the Crimea region. He discovered that both incidents of disease were caused by an extremely minuscule infectious agent, capable of permeating porcelain Chamberland filters, something which bacteria could never do. He described his findings in an article (1892) and a dissertation (1902). Then he worked at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chamberland Filter
A Chamberland filter, also known as a Pasteur–Chamberland filter, is a porcelain water filter invented by Charles Chamberland in 1884. It was developed after Henry Doulton, Henry Doulton's ceramic water filter of 1827. It is similar to the Berkefeld filter in principle. Design The filter consists of a permeable unglazed porcelain tube (called bisque) that contains a ring of enameled porcelain through which the inflow pipe fits. The core of the porcelain is made up of a metal pipe with holes through which water flows out and is collected. Inflow is pressurized so filtration occurs under force. There are 13 types: ''L1'' to ''L13''. L1 filters have the coarsest pore size while L13 have the finest. Usefulness The Pasteur-Chamberland filter is as useful as other ceramic and porcelain filters. It is a good bacterial water filter used mainly as a high volume water filter.Textbook of Microbiology by Ananthanarayan and Panikar, The filter works more quickly when the water su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optical Microscope
The optical microscope, also referred to as a light microscope, is a type of microscope that commonly uses visible light and a system of lenses to generate magnified images of small objects. Optical microscopes are the oldest design of microscope and were possibly invented in their present compound form in the 17th century. Basic optical microscopes can be very simple, although many complex designs aim to improve resolution and sample contrast. The object is placed on a stage and may be directly viewed through one or two eyepieces on the microscope. In high-power microscopes, both eyepieces typically show the same image, but with a stereo microscope, slightly different images are used to create a 3-D effect. A camera is typically used to capture the image ( micrograph). The sample can be lit in a variety of ways. Transparent objects can be lit from below and solid objects can be lit with light coming through ( bright field) or around ( dark field) the objective lens. Po ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optical Microscopy
Optics is the branch of physics that studies the behaviour and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behaviour of visible, ultraviolet, and infrared light. Because light is an electromagnetic wave, other forms of electromagnetic radiation such as X-rays, microwaves, and radio waves exhibit similar properties. Most optical phenomena can be accounted for by using the classical electromagnetic description of light. Complete electromagnetic descriptions of light are, however, often difficult to apply in practice. Practical optics is usually done using simplified models. The most common of these, geometric optics, treats light as a collection of rays that travel in straight lines and bend when they pass through or reflect from surfaces. Physical optics is a more comprehensive model of light, which includes wave effects such as diffraction and interference that cannot b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Toxin
A toxin is a naturally occurring organic poison produced by metabolic activities of living cells or organisms. Toxins occur especially as a protein or conjugated protein. The term toxin was first used by organic chemist Ludwig Brieger (1849–1919) and is derived from the word toxic. Toxins can be small molecules, peptides, or proteins that are capable of causing disease on contact with or absorption by body tissues interacting with biological macromolecules such as enzymes or cellular receptors. Toxins vary greatly in their toxicity, ranging from usually minor (such as a bee sting) to potentially fatal even at extremely low doses (such as botulinum toxin). Toxins are largely secondary metabolites, which are organic compounds that are not directly involved in an organism's growth, development, or reproduction, instead often aiding it in matters of defense. Terminology Toxins are often distinguished from other chemical agents strictly based on their biological origin. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bacteria
Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among the first life forms to appear on Earth, and are present in most of its habitats. Bacteria inhabit soil, water, acidic hot springs, radioactive waste, and the deep biosphere of Earth's crust. Bacteria are vital in many stages of the nutrient cycle by recycling nutrients such as the fixation of nitrogen from the atmosphere. The nutrient cycle includes the decomposition of dead bodies; bacteria are responsible for the putrefaction stage in this process. In the biological communities surrounding hydrothermal vents and cold seeps, extremophile bacteria provide the nutrients needed to sustain life by converting dissolved compounds, such as hydrogen sulphide and methane, to energy. Bacteria also live in symbiotic and parasitic r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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