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80-400: (Redirected from Warburg Effect ) The Warburg effect , named for Otto Heinrich Warburg , may refer to: Warburg effect (embryology) Warburg effect inversion Warburg effect (oncology) Warburg effect (plant physiology) See also [ edit ] Warburg hypothesis Oncometabolism#Warburg Effect Topics referred to by

160-564: A decree in 1937 that forbade Germans from accepting Nobel Prizes. According to the Nobel Foundation, this rumor is not true; although he was considered a worthy candidate, he was not selected for the prize at that time. Three scientists who worked in Warburg's lab, including Sir Hans Adolf Krebs , went on to win the Nobel Prize in future years. Among other discoveries, Krebs is credited with

240-481: A few words, the prime cause of cancer is the replacement of the respiration of oxygen in normal body cells by a fermentation of sugar. Warburg continued to develop the hypothesis experimentally and gave several prominent lectures outlining the theory and the data. Today, mutations in oncogenes and tumor suppressor genes are thought to be responsible for malignant transformation , and the metabolic changes Warburg thought of as causative are now considered to be

320-447: A free-swimming blastula embryo in as few as 12 hours. Initially a simple ball of cells, the blastula soon transforms into a cone-shaped echinopluteus larva. In most species, this larva has 12 elongated arms lined with bands of cilia that capture food particles and transport them to the mouth. In a few species, the blastula contains supplies of nutrient yolk and lacks arms, since it has no need to feed. Several months are needed for

400-504: A hemal system with a complex network of vessels in the mesenteries around the gut, but little is known of the functioning of this system. However, the main circulatory fluid fills the general body cavity, or coelom . This coelomic fluid contains phagocytic coelomocytes, which move through the vascular and hemal systems and are involved in internal transport and gas exchange. The coelomocytes are an essential part of blood clotting , but also collect waste products and actively remove them from

480-416: A mistranslation. Aristotle's lantern is actually referring to the whole shape of sea urchins, which look like the ancient lamps of Aristotle's time. Heart urchins are unusual in not having a lantern. Instead, the mouth is surrounded by cilia that pull strings of mucus containing food particles towards a series of grooves around the mouth. The lantern, where present, surrounds both the mouth cavity and

560-434: A multipart process which dramatically rearranges its structure by invagination to produce the three germ layers , involving an epithelial-mesenchymal transition ; primary mesenchyme cells move into the blastocoel and become mesoderm . It has been suggested that epithelial polarity together with planar cell polarity might be sufficient to drive gastrulation in sea urchins. An unusual feature of sea urchin development

640-430: A result of these mutations. A recent reevaluation of the data from nuclear/cytoplasm transfer experiments, where nuclei from cancer cells are placed in normal cytoplasm and where nuclei from normal cells are placed in cancer cytoplasm, support the role of metabolism in cancer and the mitochondria in aiding tumor suppression. Still, as evident from the references therein, this promising phenomenon still fails to explain

720-437: A strength that allow them to overcome the excellent protective features of sea urchins. Left unchecked by predators, urchins devastate their environments, creating what biologists call an urchin barren , devoid of macroalgae and associated fauna . Sea urchins graze on the lower stems of kelp, causing the kelp to drift away and die. Loss of the habitat and nutrients provided by kelp forests leads to profound cascade effects on

800-411: A toothband with a hard tooth pointing towards the centre of the mouth. Specialised muscles control the protrusion of the apparatus and the action of the teeth, and the animal can grasp, scrape, pull and tear. The structure of the mouth and teeth have been found to be so efficient at grasping and grinding that similar structures have been tested for use in real-world applications. On the upper surface of

880-406: A way similar to that of starfish; regular sea urchins do not have any favourite walking direction. The tube feet protrude through pairs of pores in the test, and are operated by a water vascular system ; this works through hydraulic pressure , allowing the sea urchin to pump water into and out of the tube feet. During locomotion, the tube feet are assisted by the spines which can be used for pushing

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960-544: A wide range of invertebrates, such as mussels , polychaetes , sponges , brittle stars, and crinoids, making them omnivores, consumers at a range of trophic levels . Mass mortality of sea urchins was first reported in the 1970s, but diseases in sea urchins had been little studied before the advent of aquaculture. In 1981, bacterial "spotting disease" caused almost complete mortality in juvenile Pseudocentrotus depressus and Hemicentrotus pulcherrimus , both cultivated in Japan;

1040-442: Is a large nerve ring encircling the mouth just inside the lantern. From the nerve ring, five nerves radiate underneath the radial canals of the water vascular system, and branch into numerous finer nerves to innervate the tube feet, spines, and pedicellariae . Sea urchins are sensitive to touch, light, and chemicals. There are numerous sensitive cells in the epithelium, especially in the spines, pedicellaria and tube feet, and around

1120-452: Is derived from the Old French herichun , from Latin ericius ('hedgehog'). Like other echinoderms, sea urchin early larvae have bilateral symmetry, but they develop five-fold symmetry as they mature. This is most apparent in the "regular" sea urchins, which have roughly spherical bodies with five equally sized parts radiating out from their central axes. The mouth is at the base of

1200-545: Is different from Wikidata All article disambiguation pages All disambiguation pages Otto Heinrich Warburg Otto Heinrich Warburg was born in Freiburg im Breisgau in 1883, close to the Swiss border. Otto's mother was the daughter of a Protestant family of bankers and civil servants from Baden . His father, Emil Warburg , had converted to Protestantism as an adult, although Emil's parents were Orthodox Jews . Emil

1280-409: Is established before the egg is fertilized. The oral-aboral axis is specified early in cleavage, and the left-right axis appears at the late gastrula stage. In most cases, the female's eggs float freely in the sea, but some species hold onto them with their spines, affording them a greater degree of protection. The unfertilized egg meets with the free-floating sperm released by males, and develops into

1360-418: Is in contrast to healthy cells, which generate energy mainly from oxidative breakdown of pyruvate . Pyruvate is an end product of glycolysis and is oxidized within the mitochondria . Hence, according to Warburg, cancer should be interpreted as a mitochondrial dysfunction. Cancer, above all other diseases, has countless secondary causes. But, even for cancer, there is only one prime cause. Summarized in

1440-409: Is known as Aristotle's lantern from Aristotle 's description in his History of Animals (translated by D'Arcy Thompson ): ... the urchin has what we mainly call its head and mouth down below, and a place for the issue of the residuum up above. The urchin has, also, five hollow teeth inside, and in the middle of these teeth a fleshy substance serving the office of a tongue . Next to this comes

1520-588: Is known to have factored in eye color and face shape when evaluating Aryanization applications. Warburg disagreed with the Nazi regime, and refused to acknowledge the Nazi salute, to the point of provoking retaliation from its officers. Authors have speculated on why he stayed in Germany under the Reich. Apple suggests that, like many others, he did not imagine how bad things could get. His own egotism may have led him to underestimate

1600-499: Is not obvious in the living animal, but is easily visible in the dried test . Specifically, the term "sea urchin" refers to the "regular echinoids", which are symmetrical and globular, and includes several different taxonomic groups, with two subclasses: Euechinoidea ("modern" sea urchins, including irregular ones) and Cidaroidea , or "slate-pencil urchins", which have very thick, blunt spines, with algae and sponges growing on them. The "irregular" sea urchins are an infra-class inside

1680-428: Is present. Densities decrease in winter when storms cause them to seek protection in cracks and around larger underwater structures. The shingle urchin ( Colobocentrotus atratus ), which lives on exposed shorelines, is particularly resistant to wave action. It is one of the few sea urchin that can survive many hours out of water. Sea urchins can be found in all climates, from warm seas to polar oceans. The larvae of

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1760-461: Is regarded as the highest award in Germany for biochemists and molecular biologists. It has been endowed with prize money, sponsored by the publishing company Elsevier/BBA. Sea urchin Sea urchins or urchins ( / ˈ ɜːr tʃ ɪ n z / ) are typically spiny , globular animals , echinoderms in the class Echinoidea. About 950 species live on the seabed, inhabiting all oceans and depth zones from

1840-400: Is the replacement of the larva's bilateral symmetry by the adult's broadly fivefold symmetry. During cleavage, mesoderm and small micromeres are specified. At the end of gastrulation, cells of these two types form coelomic pouches. In the larval stages, the adult rudiment grows from the left coelomic pouch; after metamorphosis, that rudiment grows to become the adult. The animal-vegetal axis

1920-564: The Bilateria , along with chordates , arthropods , annelids and molluscs . Sea urchins are found in every ocean and in every climate, from the tropics to the polar regions , and inhabit marine benthic (sea bed) habitats, from rocky shores to hadal zone depths. The fossil record of the Echinoids dates from the Ordovician period, some 450 million years ago. The closest echinoderm relatives of

2000-577: The Issels treatment , an ineffective regimen claimed to treat cancer, Warburg offered to testify on Issels' behalf at his appeal to the German Supreme Court. All of Issels' convictions were overturned. Warburg resided in the Kaiser Wilhelm Institute with his companion of 50 years, Jacob Heiss, the secretary and manager of the Kaiser Wilhelm Institute . Warburg pursued his research until

2080-734: The Kaiser-Wilhelm-Gesellschaft ). By 1931 he was named director of the Kaiser Wilhelm Institute for Cell Physiology , which had been founded the previous year by a donation of the Rockefeller Foundation to the Kaiser Wilhelm Gesellschaft (since renamed the Max Planck Society ). Warburg investigated the metabolism of tumors and the respiration of cells , particularly cancer cells, and in 1931

2160-474: The Middle Ordovician period ( circa 465 Mya ). There is a rich fossil record, their hard tests made of calcite plates surviving in rocks from every period since then. Spines are present in some well-preserved specimens, but usually only the test remains. Isolated spines are common as fossils. Some Jurassic and Cretaceous Cidaroida had very heavy, club-shaped spines. Most fossil echinoids from

2240-581: The Paleozoic era are incomplete, consisting of isolated spines and small clusters of scattered plates from crushed individuals, mostly in Devonian and Carboniferous rocks. The shallow-water limestones from the Ordovician and Silurian periods of Estonia are famous for echinoids. Paleozoic echinoids probably inhabited relatively quiet waters. Because of their thin tests, they would certainly not have survived in

2320-429: The esophagus , and then the stomach , divided into five parts, and filled with excretion, all the five parts uniting at the anal vent, where the shell is perforated for an outlet ... In reality the mouth-apparatus of the urchin is continuous from one end to the other, but to outward appearance it is not so, but looks like a horn lantern with the panes of horn left out. However, this has recently been proven to be

2400-694: The hadal zone and have been collected as deep as 6850 metres beneath the surface in the Sunda Trench . Nevertheless, this makes sea urchin the class of echinoderms living the least deep, compared to brittle stars , starfish and crinoids that remain abundant below 8,000 m (26,250 ft) and sea cucumbers which have been recorded from 10,687 m (35,100 ft). Population densities vary by habitat, with more dense populations in barren areas as compared to kelp stands. Even in these barren areas, greatest densities are found in shallow water. Populations are generally found in deeper water if wave action

2480-402: The pharynx . At the top of the lantern, the pharynx opens into the esophagus, which runs back down the outside of the lantern, to join the small intestine and a single caecum . The small intestine runs in a full circle around the inside of the test, before joining the large intestine, which completes another circuit in the opposite direction. From the large intestine, a rectum ascends towards

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2560-471: The slate pencil urchin are popular in aquaria, where they are useful for controlling algae. Fossil urchins have been used as protective amulets . Sea urchins are members of the phylum Echinodermata , which also includes starfish , sea cucumbers , sand dollars , brittle stars , and crinoids . Like other echinoderms, they have five-fold symmetry (called pentamerism ) and move by means of hundreds of tiny, transparent, adhesive " tube feet ". The symmetry

2640-643: The Euechinoidea, called Irregularia , and include Atelostomata and Neognathostomata . Irregular echinoids include flattened sand dollars , sea biscuits , and heart urchins . Together with sea cucumbers ( Holothuroidea ), they make up the subphylum Echinozoa , which is characterized by a globoid shape without arms or projecting rays. Sea cucumbers and the irregular echinoids have secondarily evolved diverse shapes. Although many sea cucumbers have branched tentacles surrounding their oral openings, these have originated from modified tube feet and are not homologous to

2720-543: The Marine Biological Station, Warburg performed research on oxygen consumption in sea urchin eggs after fertilization and showed that upon fertilization the rate of respiration increases as much as sixfold. His experiments also showed that iron is essential for the development of the larval stage. In 1918, Warburg was appointed professor at the Kaiser Wilhelm Institute for Biology in Berlin-Dahlem (part of

2800-579: The Reichsbürgergesetz from 1935 (cf. Nuremberg Laws ) Warburg, as a " half-Jew " was labeled a Halbjude or Mischling . Warburg was also at risk due to his relationship with Jacob Heiss, with whom he lived and worked. Beginning around 1918, Heiss served variously as Warburg's personal aid, secretary, and administrative assistant. The couple lived together in an elegant villa in Dahlem, in Berlin. Warburg

2880-449: The U.S. National Research Council to study with Warburg. During his time with Warburg, 1932–1933, Wald discovered vitamin A in the retina . When the Nazis came to power, people of Jewish descent were forced from their professional positions, although the Nazis made exceptions. Warburg had a Protestant mother and a father with Jewish heritage (who had converted to Protestantism). According to

2960-658: The age of 86. He left his entire estate to Heiss. In 1968, he suffered a broken femur . This was complicated by deep vein thrombosis . He died in 1970 from pulmonary embolism and was buried in a Christian cemetery. The Otto Warburg Medal is intended to commemorate Warburg's outstanding achievements. It has been awarded by the German Society for Biochemistry and Molecular Biology ( Gesellschaft für Biochemie und Molekularbiologie ) since 1963. The prize honors and encourages pioneering achievements in fundamental biochemical and molecular biological research. The Otto Warburg Medal

3040-460: The ambulacral areas; their function is to help in gravitational orientation. Sea urchins are dioecious , having separate male and female sexes, although no distinguishing features are visible externally. In addition to their role in reproduction, the gonads are also nutrient storing organs, and are made up of two main type of cells: germ cells , and somatic cells called nutritive phagocytes. Regular sea urchins have five gonads, lying underneath

3120-454: The animal and the anus at the top; the lower surface is described as "oral" and the upper surface as "aboral". Several sea urchins, however, including the sand dollars, are oval in shape, with distinct front and rear ends, giving them a degree of bilateral symmetry. In these urchins, the upper surface of the body is slightly domed, but the underside is flat, while the sides are devoid of tube feet. This "irregular" body form has evolved to allow

3200-412: The animal is low in oxygen. Tube feet can also act as respiratory organs, and are the primary sites of gas exchange in heart urchins and sand dollars, both of which lack gills. The inside of each tube foot is divided by a septum which reduces diffusion between the incoming and outgoing streams of fluid. The nervous system of sea urchins has a relatively simple layout. With no true brain, the neural center

3280-436: The animals to burrow through sand or other soft materials. The internal organs are enclosed in a hard shell or test composed of fused plates of calcium carbonate covered by a thin dermis and epidermis . The test is referred to as an endoskeleton rather than exoskeleton even though it encloses almost all of the urchin. This is because it is covered with a thin layer of muscle and skin; sea urchins also do not need to molt

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3360-451: The anus. Despite the names, the small and large intestines of sea urchins are in no way homologous to the similarly named structures in vertebrates. Digestion occurs in the intestine, with the caecum producing further digestive enzymes . An additional tube, called the siphon, runs beside much of the intestine, opening into it at both ends. It may be involved in resorption of water from food. The water vascular system leads downwards from

3440-545: The arms of the crinoids, sea stars, and brittle stars. Urchins typically range in size from 3 to 10 cm (1 to 4 in), but the largest species can reach up to 36 cm (14 in). They have a rigid, usually spherical body bearing moveable spines, which give the class the name Echinoidea (from the Greek ἐχῖνος ekhinos 'spine'). The name urchin is an old word for hedgehog , which sea urchins resemble; they have archaically been called sea hedgehogs . The name

3520-591: The body along or to lift the test off the substrate. Movement is generally related to feeding, with the red sea urchin ( Mesocentrotus franciscanus ) managing about 7.5 cm (3 in) a day when there is ample food, and up to 50 cm (20 in) a day where there is not. An inverted sea urchin can right itself by progressively attaching and detaching its tube feet and manipulating its spines to roll its body upright. Some species bury themselves in soft sediment using their spines, and Paracentrotus lividus uses its jaws to burrow into soft rocks. The mouth lies in

3600-431: The body through the gills and tube feet. Most sea urchins possess five pairs of external gills attached to the peristomial membrane around their mouths. These thin-walled projections of the body cavity are the main organs of respiration in those urchins that possess them. Fluid can be pumped through the gills' interiors by muscles associated with the lantern, but this does not provide a continuous flow, and occurs only when

3680-423: The centre of the oral surface in regular urchins, or towards one end in irregular urchins. It is surrounded by lips of softer tissue, with numerous small, embedded bony pieces. This area, called the peristome, also includes five pairs of modified tube feet and, in many species, five pairs of gills. The jaw apparatus consists of five strong arrow-shaped plates known as pyramids, the ventral surface of each of which has

3760-622: The chalk of the Cretaceous period, serve as zone or index fossils. Because they are abundant and evolved rapidly, they enable geologists to date the surrounding rocks. In the Paleogene and Neogene periods ( circa 66 to 2.6 Mya), sand dollars (Clypeasteroida) arose. Their distinctive, flattened tests and tiny spines were adapted to life on or under loose sand in shallow water, and they are abundant as fossils in southern European limestones and sandstones. Echinoids are deuterostome animals, like

3840-464: The confines of academia. Toward the end of the war, when the outcome was unmistakable, Albert Einstein , who had been a friend of Warburg's father Emil, wrote to Warburg at the behest of friends, asking him to leave the army and return to academia, since it would be a tragedy for the world to lose his talents. Einstein and Warburg later became friends, and Einstein's work in physics had a great influence on Warburg's biochemical research. While working at

3920-438: The disease recurred in succeeding years. It was divided into a cool-water "spring" disease and a hot-water "summer" form. Another condition, bald sea urchin disease , causes loss of spines and skin lesions and is believed to be bacterial in origin. Adult sea urchins are usually well protected against most predators by their strong and sharp spines, which can be venomous in some species. The small urchin clingfish lives among

4000-538: The identification of the citric acid cycle (or Szent-Györgyi-Krebs cycle). Warburg's combined work in plant physiology , cell metabolism , and oncology made him an integral figure in the later development of systems biology . He worked with Dean Burk on the quantum yield of photosynthesis . Warburg hypothesized that cancer growth is caused by tumor cells generating energy (as, e.g., adenosine triphosphate /ATP) mainly by anaerobic breakdown of glucose (known as fermentation , or anaerobic respiration ). This

4080-406: The interambulacral regions of the test, while the irregular forms mostly have four, with the hindmost gonad being absent; heart urchins have three or two. Each gonad has a single duct rising from the upper pole to open at a gonopore lying in one of the genital plates surrounding the anus. Some burrowing sand dollars have an elongated papilla that enables the liberation of gametes above the surface of

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4160-560: The intertidal downwards, at an extremely wide range of depths. Some species, such as Cidaris abyssicola , can live at depths of several kilometres. Many genera are found in only the abyssal zone , including many cidaroids , most of the genera in the Echinothuriidae family, and the "cactus urchins" Dermechinus . One of the deepest-living families is the Pourtalesiidae , strange bottle-shaped irregular sea urchins that live in only

4240-626: The intertidal to 5,000 metres (16,000 ft; 2,700 fathoms). Their tests (hard shells) are round and spiny, typically from 3 to 10 cm (1 to 4 in) across. Sea urchins move slowly, crawling with their tube feet , and sometimes pushing themselves with their spines. They feed primarily on algae but also eat slow-moving or sessile animals. Their predators include sharks , sea otters , starfish , wolf eels , and triggerfish . Like all echinoderms, adult sea urchins have fivefold symmetry with their pluteus larvae featuring bilateral (mirror) symmetry ; The latter indicates that they belong to

4320-808: The larva to complete its development, the change into the adult form beginning with the formation of test plates in a juvenile rudiment which develops on the left side of the larva, its axis being perpendicular to that of the larva. Soon, the larva sinks to the bottom and metamorphoses into a juvenile urchin in as little as one hour. In some species, adults reach their maximum size in about five years. The purple urchin becomes sexually mature in two years and may live for twenty. Red sea urchins were originally thought to live 7 to 10 years but recent studies have shown that they can live for more than 100 years. Canadian red urchins have been found to be around 200 years old. Sea urchins feed mainly on algae , so they are primarily herbivores , but can feed on sea cucumbers and

4400-435: The madreporite through the slender stone canal to the ring canal, which encircles the oesophagus. Radial canals lead from here through each ambulacral area to terminate in a small tentacle that passes through the ambulacral plate near the aboral pole. Lateral canals lead from these radial canals, ending in ampullae. From here, two tubes pass through a pair of pores on the plate to terminate in the tube feet. Sea urchins possess

4480-409: The marine ecosystem. Sea otters have re-entered British Columbia , dramatically improving coastal ecosystem health. The spines , long and sharp in some species, protect the urchin from predators . Some tropical sea urchins like Diadematidae , Echinothuriidae and Toxopneustidae have venomous spines. Other creatures also make use of these defences; crabs, shrimps and other organisms shelter among

4560-474: The mouth. Although they do not have eyes or eye spots (except for diadematids , which can follow a threat with their spines), the entire body of most regular sea urchins might function as a compound eye. In general, sea urchins are negatively attracted to light, and seek to hide themselves in crevices or under objects. Most species, apart from pencil urchins , have statocysts in globular organs called spheridia. These are stalked structures and are located within

4640-635: The origin of cancer as Warburg originally proposed. While Warburg's hypothesis certainly inspired the scientific community to further investigate the field of cancer metabolism, his tendency to oversimplify perhaps prevented him from accepting the vastly complex role and interactions between both the mitochondria and nucleus , or more generally, metabolism and mutations. Otto Warburg edited and had much of his original work published in The Metabolism of Tumours (tr. 1931) and wrote New Methods of Cell Physiology (1962). An unabashed anglophile , Otto Warburg

4720-456: The plates are covered in rounded tubercles to which the spines are attached. The spines are used for defence and for locomotion and come in a variety of forms. The inner surface of the test is lined by peritoneum . Sea urchins convert aqueous carbon dioxide using a catalytic process involving nickel into the calcium carbonate portion of the test. Most species have two series of spines, primary (long) and secondary (short), distributed over

4800-467: The polar sea urchin Sterechinus neumayeri have been found to use energy in metabolic processes twenty-five times more efficiently than do most other organisms. Despite their presence in nearly all the marine ecosystems, most species are found on temperate and tropical coasts, between the surface and some tens of meters deep, close to photosynthetic food sources. The earliest echinoid fossils date to

4880-478: The potential threat posed by the Nazis. Others have suggested that Warburg was so totally devoted to his work that he was prepared not only to stay in Germany but to tolerate the treatment of his Jewish colleagues and relatives by the Nazis. An anecdote from Birgit Vennesland , who became a director at Warburg's institute in West Berlin in 1968, is suggestive. She said that Warburg's advice for an acquaintance who

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4960-569: The prospect of moving to the United States, but was turned down. In 1944, Warburg was nominated for a second Nobel Prize in Physiology by Albert Szent-Györgyi , for his work on nicotinamide , the mechanism and enzymes involved in fermentation, and the discovery of flavin (in yellow enzymes ). Some sources report that he was selected to receive the award that year, but was prevented from receiving it by Adolf Hitler's regime , which had issued

5040-425: The same term [REDACTED] This disambiguation page lists articles associated with the title Warburg effect . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=Warburg_effect&oldid=1250825330 " Category : Disambiguation pages Hidden categories: Short description

5120-489: The sea urchin are the sea cucumbers (Holothuroidea), which like them are deuterostomes , a clade that includes the chordates . ( Sand dollars are a separate order in the sea urchin class Echinoidea.) The animals have been studied since the 19th century as model organisms in developmental biology , as their embryos were easy to observe. That has continued with studies of their genomes because of their unusual fivefold symmetry and relationship to chordates. Species such as

5200-418: The sediment. The gonads are lined with muscles underneath the peritoneum, and these allow the animal to squeeze its gametes through the duct and into the surrounding sea water, where fertilization takes place. During early development, the sea urchin embryo undergoes 10 cycles of cell division , resulting in a single epithelial layer enveloping the blastocoel . The embryo then begins gastrulation ,

5280-444: The spines of urchins such as Diadema ; juveniles feed on the pedicellariae and sphaeridia, adult males choose the tube feet and adult females move away to feed on shrimp eggs and molluscs. Sea urchins are one of the favourite foods of many lobsters , crabs , triggerfish , California sheephead , sea otter and wolf eels (which specialise in sea urchins). All these animals carry particular adaptations (teeth, pincers, claws) and

5360-467: The spines, and often adopt the colouring of their host. Some crabs in the Dorippidae family carry sea urchins, starfish, sharp shells or other protective objects in their claws. Pedicellariae are a good means of defense against ectoparasites, but not a panacea as some of them actually feed on it. The hemal system defends against endoparasites. Sea urchins are established in most seabed habitats from

5440-541: The surface of the body, with the shortest at the poles and the longest at the equator. The spines are usually hollow and cylindrical. Contraction of the muscular sheath that covers the test causes the spines to lean in one direction or another, while an inner sheath of collagen fibres can reversibly change from soft to rigid which can lock the spine in one position. Located among the spines are several types of pedicellaria , moveable stalked structures with jaws. Sea urchins move by walking, using their many flexible tube feet in

5520-461: The test at the aboral pole is a membrane, the periproct , which surrounds the anus . The periproct contains a variable number of hard plates, five of which, the genital plates, contain the gonopores, and one is modified to contain the madreporite , which is used to balance the water vascular system. The mouth of most sea urchins is made up of five calcium carbonate teeth or plates, with a fleshy, tongue-like structure within. The entire chewing organ

5600-569: The upper Triassic, their numbers increased again. Cidaroids have changed very little since the Late Triassic , and are the only Paleozoic echinoid group to have survived. The euechinoids diversified into new lineages in the Jurassic and Cretaceous periods, and from them emerged the first irregular echinoids (the Atelostomata ) during the early Jurassic. Some echinoids, such as Micraster in

5680-568: The wave-battered coastal waters inhabited by many modern echinoids. Echinoids declined to near extinction at the end of the Paleozoic era, with just six species known from the Permian period. Only two lineages survived this period's massive extinction and into the Triassic : the genus Miocidaris , which gave rise to modern cidaroida (pencil urchins), and the ancestor that gave rise to the euechinoids . By

5760-421: The way invertebrates with true exoskeletons do, instead the plates forming the test grow as the animal does. The test is rigid, and divides into five ambulacral grooves separated by five wider interambulacral areas. Each of these ten longitudinal columns consists of two sets of plates (thus comprising 20 columns in total). The ambulacral plates have pairs of tiny holes through which the tube feet extend. All of

5840-619: Was a member of the illustrious Warburg family of Altona . Emil was also president of the Physikalische Reichsanstalt, Wirklicher Geheimer Oberregierungsrat (True Senior Privy Counselor). Otto Warburg studied chemistry under Emil Fischer , and earned his doctorate in chemistry in Berlin in 1906. He then studied under Ludolf von Krehl and earned the degree of doctor of medicine in Heidelberg in 1911. Between 1908 and 1914, Warburg

5920-738: Was affiliated with the Naples Marine Biological Station , (in Naples , Italy), where he conducted research. In later years, he would return for visits, and maintained a lifelong friendship with the family of the station's director, Anton Dohrn . A lifelong equestrian, he served as an officer in the elite Uhlans (cavalry) on the front during the First World War , where he won the Iron Cross . Warburg later credited this experience with affording him invaluable insights into "real life" outside

6000-547: Was awarded the Nobel Prize in Physiology for his "discovery of the nature and mode of action of the respiratory enzyme". In particular, he discovered that animal tumors produce large quantities of lactic acid . The award came after receiving 46 nominations over a period of nine years beginning in 1923, 13 of which were submitted in 1931, the year he won the prize. The Nobel laureate George Wald , having completed his Ph.D. in zoology at Columbia University, received an award from

6080-452: Was banned from teaching, but allowed to carry on his research. In 1941, Warburg briefly lost his post for making remarks critical of the Nazi regime, but in a few weeks was able to resume his research following a personal order from Hitler's Chancellery. Hermann Göring also arranged for him to be classified as one-quarter Jewish. In September 1942, Warburg made an official request for equal status ("Gleichstellung") with German Aryans , which

6160-410: Was experiencing emotional difficulties was "Tell him not to think about anything but science—think about absolutely nothing else—only science." In 1943 Warburg relocated his laboratory to the village of Liebenburg on the outskirts of Berlin to avoid ongoing air raids. The Rockefeller Foundation reportedly offered to continue funding his work if he emigrated. After the war ended, Warburg inquiried about

6240-588: Was granted. The Nazis were willing to allow Warburg to work because of his focus on metabolism and cancer. Hitler was obsessed with cancer, having lost his own mother to breast cancer at an early age. The decisive factor was Warburg's distinguished military service in the Great War, as Jewish veterans were often exempted from the loss of citizenship mandated by the Nuremberg laws. Warburg's Germanic physiognomy may also have weighed in his favor, as Hitler's Chancellery

6320-430: Was known to quote an aphorism he attributed to Max Planck : "Science advances one funeral at a time". Seemingly utterly convinced of the accuracy of his conclusions, Warburg expressed dismay at the "continual discovery of cancer agents and cancer viruses" that he expected to "hinder necessary preventive measures and thereby become responsible for cancer cases". When Josef Issels was tried and convicted for promoting

6400-467: Was thrilled when Oxford University awarded him an honorary doctorate. He was awarded the Order Pour le Mérite in 1952 and was known to tell other universities not to bother with honorary doctorates. He would ask officials to mail him medals he had been awarded so as to avoid a ceremony that would separate him from his beloved laboratory. When frustrated by the lack of acceptance of his ideas, Warburg

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