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#10755. What does the term in Biology Genetic variation mean?

#10756. What does the term in Biology Genetics mean?

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#2572. What does the medical term Goblet cell mean?

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#9857.

2436) Daniel Bovet

Gist:

Work

Hormones and signal substances are chemical materials that convey signals governing different parts of the body. These substances include histamines, which are involved in allergic reactions, and it can be difficult to moderate their effects. Daniel Bovet looked for substances that block histamines, and in 1937 he found the first antihistamine, which later led to other antihistamine formulations to relieve allergies. Bovet also produced additional substances that block signal substances in other ways and have a numbing effect, among other things.

Summary

Daniel Bovet (born March 23, 1907, Neuchâtel, Switz.—died April 8, 1992, Rome, Italy) was a Swiss-born Italian pharmacologist who received the 1957 Nobel Prize for Physiology or Medicine for his discoveries of certain chemotherapeutic agents—namely, sulfa drugs, antihistamines, and muscle relaxants.

Bovet studied at the University of Geneva, graduating with a doctorate in science in 1929. That same year, he went on to the Pasteur Institute in Paris and became head of the therapeutic chemistry laboratory there in 1939. In 1937 Bovet discovered the first antihistamine substance, which (in counteracting the effect of histamine) is effective in treating allergic reactions. This discovery led to development of the first antihistamine drug for humans in 1942, and in 1944 one of Bovet’s own discoveries, pyrilamine, was produced as a drug.

In 1947 Bovet was invited to establish a laboratory of chemotherapeutics at the Superior Institute of Health in Rome, and eventually he took Italian citizenship. There he turned his attention to curare, a drug used to relax muscles during surgery. Because the drug was expensive and somewhat unpredictable in its effects, a low-cost dependable synthetic alternative was desired. Bovet produced hundreds of synthetic alternatives, of which gallamine and succinylcholine came into widespread use.

In 1964 Bovet became professor of pharmacology at the University of Sassari, on the Italian island of Sardinia. He served as the head of the psychobiology and psychopharmacology laboratory of the National Research Council (Rome) from 1969 until 1971, when he became professor of psychobiology at the University of Rome (1971–82).

Details

Daniel Bovet (23 March 1907 – 8 April 1992) was a Swiss-born Italian pharmacologist who won the 1957 Nobel Prize in Physiology or Medicine for his discovery of drugs that block the actions of specific neurotransmitters. He is best known for his discovery in 1937 of antihistamines, which block the neurotransmitter histamine and are used in allergy medication. His other research included work on chemotherapy, sulfa drugs, the sympathetic nervous system, the pharmacology of curare, and other neuropharmacological interests.

In 1965, Bovet led a study team which concluded that smoking of tobacco cigarettes increased users' intelligence. He told The New York Times that the object was not to "create geniuses, but only [to] put the less-endowed individual in a position to reach a satisfactory mental and intellectual development".

Bovet was born in Fleurier, Switzerland. He was a native Esperanto speaker. He graduated from the University of Geneva in 1927 and received his doctorate in 1929. Between 1929 and 1947, he worked at the Pasteur Institute in Paris. He then moved to the Istituto Superiore di Sanità (Superior Institute of Health) in Rome in 1947. Two years later, in 1949, Bovet was awarded the Cameron Prize for Therapeutics of the University of Edinburgh. In 1964, he became a professor in at the University of Sassari in Italy. From 1969 to 1971, he was the head of the Psychobiology and Psychopharmacology Laboratory of the National Research Council, in Rome, before stepping down to become a professor at the University of Rome La Sapienza. He retired in 1982.

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#5949. What does the noun gore mean?

#5950. What does the adjective gorgeous mean?

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6350.

2435) Alec Todd

Gist:

Work

The substances known as deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) are found in nearly all cells in almost all organisms. The building blocks of DNA and RNA consist of nucleotides. In turn, these consist of what scientists call a nitrogen base, a sugar molecule, and one or more phosphate groups. Around 1940, Alexander Todd began to examine the composition of nucleotides more closely. Using chemical methods, Todd split nucleotides apart and compared their parts with substances that had been constructed from known components in a way that was already understood.

Summary

Alexander Robertus Todd, Baron Todd (born Oct. 2, 1907, Glasgow, Scot.—died Jan. 10, 1997, Cambridge, Eng.) was a British biochemist whose research on the structure and synthesis of nucleotides, nucleosides, and nucleotide coenzymes gained him the 1957 Nobel Prize for Chemistry.

After receiving doctorates from the universities of Frankfurt am Main (1931) and Oxford (1933), Todd held posts with the Lister Institute of Preventive Medicine, London, and the University of London before becoming professor of organic chemistry at the University of Manchester (1938–44) and then at Cambridge (1944–71), where he was also master of Christ’s College (1963–78). He was named chancellor of the University of Strathclyde in 1975 and was visiting professor at Hatfield Polytechnic (1978–86).

While at Manchester he began work on nucleosides, compounds that form the structural units of nucleic acids (DNA and RNA). In 1949 he synthesized a related substance, adenosine triphosphate (ATP), which is vital to energy utilization in living organisms. He synthesized two other important compounds, flavin adenine dinucleotide (FAD) in 1949 and uridine triphosphate in 1954. In 1955 he elucidated the structure of vitamin B12.

Todd also worked on the structure and synthesis of vitamin B1, vitamin E, and alkaloid substances found in marijuana and hashish. He studied other alkaloids as well, plant and insect pigments, and mold products, including penicillin. He served as chairman (1952–64) of the British government’s advisory committee on scientific policy, and in 1975 he was elected president of the Royal Society. Knighted in 1954, he was created a life peer in 1962 and made a member of the Royal Order of Merit in 1977.

Details

Alexander Robertus Todd, Baron Todd (2 October 1907 – 10 January 1997) was a British biochemist whose research on the structure and synthesis of nucleotides, nucleosides, and nucleotide coenzymes gained him the Nobel Prize for Chemistry in 1957.

Early life and education

Todd was born at Cathcart in outer Glasgow, the elder son of Alexander Todd,  a clerk with the Glasgow Subway, and his wife, Jane Lowry.

He attended Allan Glen's School and graduated from the University of Glasgow with a bachelor's degree (BSc) in 1928. He received a doctorate (Dr Phil.nat.) from Goethe University Frankfurt in 1931 for his thesis on the chemistry of the bile acids.

Todd was awarded an 1851 Research Fellowship from the Royal Commission for the Exhibition of 1851, and, after studying at Oriel College, Oxford, he received another doctorate (DPhil) in 1933.

Career

Todd held posts with the Lister Institute, the University of Edinburgh (staff, 1934–1936) and the University of London, where he was appointed Reader in biochemistry.

In 1938, Alexander Todd spent six months as a visiting professor at California Institute of Technology, eventually declining an offer of faculty position.

Todd became the Sir Samuel Hall Chair of Chemistry and director of the Chemical Laboratories of the University of Manchester in 1938, where he began working on nucleosides, compounds that form the structural units of nucleic acids (DNA and RNA). At 31, he was the youngest professor of chemistry since Frankland. He was elected to membership of the Manchester Literary and Philosophical Society in 1938.

In 1944, he was appointed to the 1702 Chair of Chemistry in the University of Cambridge, which he held until his retirement in 1971. In 1949, he synthesised adenosine triphosphate (ATP) and flavin adenine dinucleotide (FAD). Todd served as a visiting professor at the University of Chicago in Autumn 1948 and University of Sydney in 1950.

By 1951, Todd and collaborators at Cambridge had determined by biochemical methods how the backbone of DNA is structured via the successive linking of carbon atoms 3 and 5 of the sugar to phosphates. This helped corroborate Francis Crick and James_Watson's X-ray structural work published in 1953.

In 1955, he helped elucidate the structure of vitamin B12, although the final formula and definite structure was determined by Dorothy Hodgkin and her team, and later worked on the structure and synthesis of vitamin B1 and vitamin E, the anthocyanins (the pigments of flowers and fruits) from insects (aphids, beetles) and studied alkaloids found in cannabis. He served as chairman of the Government of the United Kingdom's advisory committee on scientific policy from 1952 to 1964.

He is credited as the first person to synthesize H4-CBD and H2-CBD from Cannabidiol by hydrogenation as early as 1940.

He received the 1957 Nobel Prize in Chemistry "for his work on nucleotides and nucleotide co-enzymes."

Elected a Fellow of Christ's College, Cambridge in 1944, he served as Master from 1963 to 1978. Lord Todd became the first Chancellor of the new University of Strathclyde in 1965, and a visiting professor at Hatfield Polytechnic (1978–1986). Among his many honours, including over 40 honorary degrees, he was elected a Fellow of the Royal Society in 1942, a member of the United States National Academy of Sciences in 1955, a member of the American Academy of Arts and Sciences in 1957, and the American Philosophical Society in 1965. President of the Royal Society from 1975 to 1980, The Queen awarded him the Order of Merit in 1977.

In 1981, Todd became a founding member of the World Cultural Council.

Personal life and death

In 1937, Todd married Alison Sarah Dale (d. 1987), daughter of Nobel Prize winner Henry Hallett Dale, who like Todd, served as President of the Royal Society of London. They had a son and two daughters:

* Dr the Hon Alexander Henry Todd (b. 1939), educated at Oriel College, Oxford, Master Salters' Company (1999/2000), m. 1stly 1967 (div 1981) Joan Margaret Koester, m. 2ndly Patricia Mary Harvey Jones, daughter of Brigadier Alan Harvey Jones CBE TD, of Somerford Booths, Cheshire;
* The Hon Helen Jean Todd (b. 1941), m. 1963 Philip Edgar Brown, and has two sons and a daughter;
* The Hon Hilary Alison Todd (b. 1946).

Todd died in Cambridge on 10 January 1997 at the age of 89 following a heart attack.

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#5947. What does the noun imbecile mean?

#5948. What does the verb (used with object) imbibe mean?

2497) Jaguar

Gist

Jaguars rarely attack humans and will almost never do so without provocation. They will, however, attack and kill livestock that local farmers rely on for their livelihoods. This prompts local communities to hunt and kill jaguars in retaliation and to protect their herds.

There is a high risk associated with keeping this species as a pet. This is not a suitable pet.

Summary

The jaguar (Panthera onca) is a large cat species and the only living member of the genus Panthera that is native to the Americas. Its distinctively marked coat features pale yellow to tan colored fur covered by spots that transition to rosettes on the sides, although a melanistic black coat appears in some individuals. With a body length of up to 1.85 m (6 ft 1 in) and a weight of up to 158 kg (348 lb), it is the biggest cat species in the Americas and the third largest in the world. The jaguar's powerful bite allows it to pierce the carapaces of turtles and tortoises, and to employ an unusual killing method: it bites directly through the skull of mammalian prey between the ears to deliver a fatal blow to the brain.

The modern jaguar's ancestors probably entered the Americas from Eurasia during the Early Pleistocene via the land bridge that once spanned the Bering Strait. The oldest jaguar fossils found in North America date to between 0.85 to 0.82 million years ago. Today, the jaguar's range extends from the Southwestern United States across Mexico and much of Central America, the Amazon rainforest and south to Paraguay and northern Argentina. It inhabits a variety of forested and open terrains, but its preferred habitat is tropical and subtropical moist broadleaf forest, wetlands and wooded regions. It is adept at swimming and is largely a solitary, opportunistic, stalk-and-ambush apex predator. As a keystone species, it plays an important role in stabilizing ecosystems and in regulating prey populations.

The jaguar is threatened by habitat loss, habitat fragmentation, poaching for trade with its body parts and killings in human–wildlife conflict situations, particularly with ranchers in Central and South America. It has been listed as Near Threatened on the IUCN Red List since 2002. The wild population is thought to have declined since the late 1990s. Priority areas for jaguar conservation comprise 51 large areas inhabited by at least 50 breeding individuals, called Jaguar Conservation Units. They are located in 36 geographic regions from Mexico to Argentina.

The jaguar has featured prominently in the mythology of indigenous peoples of the Americas, including those of the Aztec and Maya civilizations.

Details:

What is the jaguar?

Jaguars are the only big cat in the Americas and the third biggest in the world after tigers and lions. They look a lot like leopards, which live in Africa and Asia, but jaguars’ spots are more complex and often have a dot in the center.

These powerful cats were worshipped as gods in many ancient South American cultures, and representations of the jaguar show up in the art and archaeology of pre-Columbian cultures across the jaguar’s range.

Diet and behavior

Unlike many other cats, jaguars do not avoid water. In fact, they are quite good swimmers. They hunt fish, turtles, and even caimans, using their incredibly powerful jaws to pierce the animals’ skulls. Jaguars also eat deer, peccaries, capybaras, tapirs, and a number of other land animals, which they prefer to ambush at night.

Jaguars live alone, and they’re territorial—they define their area by marking with their waste or clawing trees.

Females have litters of one to four cubs, which are blind and helpless at birth. The mother stays with them and defends them fiercely from any animal that may approach—even their own father. Young jaguars learn to hunt by living with their mothers for two years or more.

Range and habitat

Jaguars once roamed broadly from central Argentina all the way up to the southwestern United States. Since the 1880s, they’ve lost more than half their territory. Their main stronghold today is the Amazon Basin, though they still exist in smaller numbers through Central America as well.

They’re typically found in tropical rainforests but also live in savannas and grasslands.

Threats to survival

Jaguars face a number of threats, including habitat fragmentation and illegal killing. South and Central America’s high rates of deforestation—for grazing land, agriculture, and other uses—have not only destroyed jaguars’ habitat but also broken it up. Fragmented forests mean that cats get boxed into patches of forest and can’t travel far to find new mates. That kind of isolation can lead to inbreeding and local extinctions.

Another threat jaguars face is retaliatory killings from ranchers. As grazing land replaces forests, jaguars are more likely to hunt cattle. In response—and sometimes in anticipation—cattle owners kill jaguars.

Poaching is another growing problem for jaguars. They’ve long been hunted for their pelts, and now there’s a growing illegal, international trade in jaguar teeth and jaguar bone products going to China.

Conservation

Jaguars are classified as near-threatened by the International Union for the Conservation of Nature. The species has national protections in almost every country it’s found, and trade in its parts is banned by CITES, a global treaty that regulates the cross-border wildlife trade. Still, poaching and the illegal trade continues so strengthening law enforcement is important.

There are major efforts to support and develop jaguar corridors to connect isolated populations as well as to work with ranchers to reduce human-jaguar conflict. Workshops help ranchers learn better husbandry practices, and a growing number of programs compensate ranchers when they lose cattle to jaguars, so that they’re less motivated to kill the cat in retaliation.

Fighting deforestation, which a number of international NGOs and indigenous groups are involved in, is critical.

Additional Information

Big cats are some of the most captivating wild animals. Elusive, powerful, and graceful. Lions and tigers are easily identifiable and greatly loved, but there’s far more to the world of big cats than these icons.

Jaguars are some of the most beautiful and mysterious big cats in the world, but few people know much about them. World Animal Protection wants to put that right.

We’ve produced a short documentary Jaguar Spirit, to highlight these incredible animals and the challenges they face. To get you ready for the documentary, let’s whet your appetite with some amazing jaguar facts.

1. Jaguars are the third largest cats in the world

Jaguars are “big” cats packed into a smaller form factor. They’re the largest cat in the Americas and are the third largest cat in the world, behind tigers and lions. Male Jaguars weigh up to 120kg, while the smaller females reach a maximum of 100kg. To put this in context, jaguars are about half the weight of a lion, but more than double that of a cheetah.

However, jaguars are no taller than a meter, making them powerful but relatively compact compared to lions and tigers.

2. Jaguars were revered by Mesoamerican civilizations

In Mesoamerican indigenous communities, jaguars were one of the most revered animals. Every major Mesoamerican civilization had a jaguar god, many of which were important parts of their religion. These communities viewed jaguars as symbols of strength and power.

For example, the Aztecs named their most elite warriors “cuāuhocēlōtl”, a combination of the Aztec words for eagle and jaguar. They wore costumes that made them resemble these majestic cats and lead their communities both on the battlefield and at home. In Aztec culture, many believed that shamans could transform into jaguars at will and would become jaguars after they died.

3. Jaguar spots are unique

Learning to tell jaguars apart from other big cats is easy. They have beautiful tan and orange fur covered with black spots known as rosettes.

These rosettes are different from the spots on any other cat. Each rosette is a jagged circle that makes up an outer ring with a single black spot in the middle.

Other spotted cats have the ring that characterises the rosettes, but none have the central spot of the jaguar.

4. Jaguars love swimming

Unlike most domestic cats, jaguars are excellent swimmers and love the water. They can fully submerge and dive in pursuit of prey if needed and won’t hesitate to attack prey animals in the water.

5. Jaguars look after their cubs

Jaguars don’t have big litters. They typically have two cubs at one time (though they can have up to four). The cubs are born completely helpless and blind. They remain with their mother for two years as they grow and learn to hunt and take care of themselves.

Jaguars are sentient beings, meaning they think and feel and have personalities and needs of their own. The breakthrough research and studies of animals' feelings and emotions show how the life of a wild animal, like a jaguar, is mentally and physically better in the wild with its cubs.

6. Jaguars are exploited for commercial purposes

Jaguars aren’t some of the most endangered animals in the world, but that doesn’t mean that the species is thriving. There are only 173,000 jaguars left in the wild, the population of jaguars is “near threatened”. Regardless of their status, jaguars should not be exploited for any commercial purposes. They are wildlife and deserve a life in the wild.

7. Jaguars live primarily in the rainforest

As opportunistic ambush predators, jaguars aren’t well-suited to large open spaces. Instead, the natural habitat of jaguars is rainforests and wetlands. Approximately half of the world’s population of jaguars live in Brazil.

The rest can be found in Mexico and Central and South America, including northern Argentina.

8. Jaguars are fast

Cheetahs are the first to come to mind when you think of fast runners in the animal kingdom. Jaguars can’t quite reach the 70 miles per hour of the cheetah, but they reach a very respectable 50mph.

This makes them the second-fastest big cats in the world. They also have an impressive ability to jump and climb when necessary.

9. Jaguars aren’t fussy eaters

Jaguars are carnivores, like all other cats. On land, they will commonly hunt deer, capybaras, and tapirs. And they’re just as comfortable in the water, seeking out fish, turtles, and caiman to meet their appetite.

As opportunistic hunters, however, they will prey on almost any animal they come across.

These techniques and their incredible bite power allows them to dispatch prey as large as cows.

10. Jaguars are crepuscular

Most of us think of animals as being either diurnal or nocturnal, but jaguars don’t fit into this pattern. They can be active either during the day or at night.

In fact, jaguars are considered crepuscular and nocturnal, meaning they’re most active during dusk and dawn. These are the times when they’re most likely to be hunting. That said, it’s also common to find them hunting during the day.

11. Jaguars travel long distances

Jaguars can regularly travel over six miles per day in search of food. They’re solitary animals, marking their territory and only getting together with others to mate. Males do not remain with females to avoid the risk of infanticide.

Where space allows, jaguars can have territories of up to 54 square miles.

12. Jaguars are struggling with the loss of their habitats

Jaguars are being threatened because their habitats are being lost to deforestation and other human activities. Much of this land has been appropriated for agricultural activities such as cattle ranching and crops used to produce animal feed.

Any reduction in habitat makes it harder for these solitary cats to maintain sufficient territory to feed themselves. It also increases the risk of conflict between individual animals.

13. Jaguar prey have also reduced in number

The loss of habitat has also impacted the animals that jaguars rely on for food. When prey becomes scarce, jaguars start looking for alternative food sources, including agricultural livestock.

The people living in areas frequented by jaguars attempt to protect their animals, which unfortunately often leads to killing the big cats threatening their livelihood.

14. Jaguars are facing increased risk from fire

Jaguar territories are increasingly at risk from fire, threatening both jaguars and the prey animals they rely on, further exacerbating the problems they already face.

Factory farming methods are becoming increasingly common throughout the Amazon, with catastrophic consequences. Fires are often deliberately set to clear large swathes of land quickly.

Once rainforests have been removed, they are replaced with monoculture crops, which are more vulnerable to wildfires than the original ecosystems.

15. Jaguars are popular targets for poaching

Despite their impressive camouflage, speed, and agility, jaguars are popular with poachers. Their beautiful fur means that they command high prices for their pelts and skins, and their sharp teeth and claws are seen as valuable trophies.

Beyond poaching for trophies, jaguars are often captured and sold as exotic pets, to private wildlife collectors, or as tourist attractions.

16. Jaguars are used in traditional Asian medicine

Jaguars are also often killed for use in traditional Asian medicine. They are typically boiled whole until they reduce down into a paste used for various purposes, from treating arthritis to improving sexual performance.

None of these animal-derived products are scientifically validated or effective.