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Esther Lederberg
Esther Miriam Zimmer Lederberg (December 18, 1922 – November 11, 2006) was an American microbiologist and a pioneer of bacterial genetics. She discovered the bacterial virus λ and the bacterial fertility factor F, devised the first implementation of replica plating, and furthered the understanding of the transfer of genes between bacteria by specialized transduction. Lederberg also founded and directed the now-defunct Plasmid Reference Center at Stanford University, where she maintained, named, and distributed plasmids of many types, including those coding for antibiotic resistance, heavy metal resistance, virulence, conjugation, colicins, transposons, and other unknown factors. As a woman in a male-dominated field and the wife of Nobel laureate Joshua Lederberg, Esther Lederberg struggled for professional recognition. Despite her foundational discoveries in the field of microbiology, she was never offered a tenured position at a university. Textbooks often ignore her w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bronx, New York
The Bronx () is a Boroughs of New York City, borough of New York City, coextensive with Bronx County, in the U.S. state, state of New York (state), New York. It is south of Westchester County, New York, Westchester County; north and east of the New York City borough of Manhattan, across the Harlem River; and north of the New York City borough of Queens, across the East River. The Bronx has a land area of and a population of 1,472,654 in the 2020 census. If each borough were ranked as a city, the Bronx would rank as the List of United States cities by population, ninth-most-populous in the U.S. Of the five boroughs, it has the fourth-largest area, fourth-highest population, and third-highest population density.New York State Department of Health''Population, Land Area, and Population Density by County, New York State – 2010'' retrieved on August 8, 2015. It is the only borough of New York City not primarily on an island. With a population that is 54.8% Hispanic as of 2020, it i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transduction (genetics)
Transduction is the process by which foreign DNA is introduced into a cell by a virus or viral vector. An example is the viral transfer of DNA from one bacterium to another and hence an example of horizontal gene transfer. Transduction does not require physical contact between the cell donating the DNA and the cell receiving the DNA (which occurs in conjugation), and it is DNase resistant (transformation is susceptible to DNase). Transduction is a common tool used by molecular biologists to stably introduce a foreign gene into a host cell's genome (both bacterial and mammalian cells). Discovery (bacterial transduction) Transduction was discovered by Norton Zinder and Joshua Lederberg at the University of Wisconsin–Madison in 1952 in Salmonella. In the lytic and lysogenic cycles Transduction happens through either the lytic cycle or the lysogenic cycle. When bacteriophages (viruses that infect bacteria) that are lytic infect bacterial cells, they harness the replicationa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neurospora Crassa
''Neurospora crassa'' is a type of red bread mold of the phylum Ascomycota. The genus name, meaning "nerve spore" in Greek, refers to the characteristic striations on the spores. The first published account of this fungus was from an infestation of French bakeries in 1843. ''Neurospora crassa'' is used as a model organism because it is easy to grow and has a haploid life cycle that makes genetics, genetic analysis simple since recessive traits will show up in the offspring. Analysis of genetic recombination is facilitated by the ordered arrangement of the products of meiosis in ''Neurospora'' ascospores. Its entire genome of seven chromosomes has been sequenced. ''Neurospora'' was used by Edward Tatum and George Wells Beadle in their experiments for which they won the Nobel Prize in Physiology or Medicine in 1958. Beadle and Tatum exposed ''N. crassa'' to x-rays, causing mutations. They then observed failures in metabolic pathways caused by errors in specific enzymes. This led t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
New York Botanical Garden
The New York Botanical Garden (NYBG) is a botanical garden at Bronx Park in the Bronx, New York City. Established in 1891, it is located on a site that contains a landscape with over one million living plants; the Enid A. Haupt Conservatory, a greenhouse containing several habitats; and the LuEsther T. Mertz Library, which contains one of the world's largest collections of botany-related texts. , over a million people visit the New York Botanical Garden annually. NYBG is also a major educational institution, teaching visitors about plant science, ecology, and healthful eating through NYBG's interactive programming. Nearly 90,000 of the annual visitors are children from underserved neighboring communities. An additional 3,000 are teachers from New York City's public school system participating in professional development programs that train them to teach science courses at all grade levels. NYBG operates one of the world's largest plant research and conservation programs. NY ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Evander Childs Educational Campus
Evander Childs Educational Campus is a cluster of public high schools located on the campus of the former Evander Childs High School in the Gun Hill section of The Bronx, New York City. The campus was named after Evander Childs, principal of Public School 10 in the Bronx who died at his work desk on April 11, 1912. In 1938, James Michael Newell, working under the Public Works of Art Project and the Federal Art Project, painted eight murals titled ''The History of Western Civilization'' at the school. As part of the mayor of the city's push of Bill & Melinda Gates Foundation's small schools initiative, Evander was labeled an "impact" school in 2008 and slated to be phased out not long afterward. Evander Childs High School was closed that year and split into six smaller, specialized schools. The campus is located at 800 East Gun Hill Road. The New York City Department of Education operates six public high schools on the Evander Childs campus: * Bronx Academy of Health Careers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hebrew Language
Hebrew (; ; ) is a Northwest Semitic language of the Afroasiatic language family. Historically, it is one of the spoken languages of the Israelites and their longest-surviving descendants, the Jews and Samaritans. It was largely preserved throughout history as the main liturgical language of Judaism (since the Second Temple period) and Samaritanism. Hebrew is the only Canaanite language still spoken today, and serves as the only truly successful example of a dead language that has been revived. It is also one of only two Northwest Semitic languages still in use, with the other being Aramaic. The earliest examples of written Paleo-Hebrew date back to the 10th century BCE. Nearly all of the Hebrew Bible is written in Biblical Hebrew, with much of its present form in the dialect that scholars believe flourished around the 6th century BCE, during the time of the Babylonian captivity. For this reason, Hebrew has been referred to by Jews as '' Lashon Hakodesh'' (, ) since an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Great Depression
The Great Depression (19291939) was an economic shock that impacted most countries across the world. It was a period of economic depression that became evident after a major fall in stock prices in the United States. The economic contagion began around September and led to the Wall Street stock market crash of October 24 (Black Thursday). It was the longest, deepest, and most widespread depression of the 20th century. Between 1929 and 1932, worldwide gross domestic product (GDP) fell by an estimated 15%. By comparison, worldwide GDP fell by less than 1% from 2008 to 2009 during the Great Recession. Some economies started to recover by the mid-1930s. However, in many countries, the negative effects of the Great Depression lasted until the beginning of World War II. Devastating effects were seen in both rich and poor countries with falling personal income, prices, tax revenues, and profits. International trade fell by more than 50%, unemployment in the U.S. rose to 23% and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orthodox Jewish
Orthodox Judaism is the collective term for the traditionalist and theologically conservative branches of contemporary Judaism. Theologically, it is chiefly defined by regarding the Torah, both Written and Oral, as revealed by God to Moses on Mount Sinai and faithfully transmitted ever since. Orthodox Judaism, therefore, advocates a strict observance of Jewish law, or ''halakha'', which is to be interpreted and determined exclusively according to traditional methods and in adherence to the continuum of received precedent through the ages. It regards the entire ''halakhic'' system as ultimately grounded in immutable revelation, and beyond external influence. Key practices are observing the Sabbath, eating kosher, and Torah study. Key doctrines include a future Messiah who will restore Jewish practice by building the temple in Jerusalem and gathering all the Jews to Israel, belief in a future bodily resurrection of the dead, divine reward and punishment for the righteous and th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bronx
The Bronx () is a borough of New York City, coextensive with Bronx County, in the state of New York. It is south of Westchester County; north and east of the New York City borough of Manhattan, across the Harlem River; and north of the New York City borough of Queens, across the East River. The Bronx has a land area of and a population of 1,472,654 in the 2020 census. If each borough were ranked as a city, the Bronx would rank as the ninth-most-populous in the U.S. Of the five boroughs, it has the fourth-largest area, fourth-highest population, and third-highest population density.New York State Department of Health''Population, Land Area, and Population Density by County, New York State – 2010'' retrieved on August 8, 2015. It is the only borough of New York City not primarily on an island. With a population that is 54.8% Hispanic as of 2020, it is the only majority-Hispanic county in the Northeastern United States and the fourth-most-populous nationwide. The Bronx ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transposons
A transposable element (TE, transposon, or jumping gene) is a nucleic acid sequence in DNA that can change its position within a genome, sometimes creating or reversing mutations and altering the cell's genetic identity and genome size. Transposition often results in duplication of the same genetic material. Barbara McClintock's discovery of them earned her a Nobel Prize in 1983. Its importance in personalized medicine is becoming increasingly relevant, as well as gaining more attention in data analytics given the difficulty of analysis in very high dimensional spaces. Transposable elements make up a large fraction of the genome and are responsible for much of the C-value, mass of DNA in a eukaryotic cell. Although TEs are selfish genetic elements, many are important in genome function and evolution. Transposons are also very useful to researchers as a means to alter DNA inside a living organism. There are at least two classes of TEs: Class I TEs or retrotransposons generally ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Colicins
A colicin is a type of bacteriocin produced by and toxic to some strains of ''Escherichia coli''. Colicins are released into the environment to reduce competition from other bacterial strains. Colicins bind to outer membrane receptors, using them to translocate to the cytoplasm or cytoplasmic membrane, where they exert their cytotoxic effect, including depolarisation of the cytoplasmic membrane, DNase activity, RNase activity, or inhibition of murein synthesis. Structure Channel-forming colicins (colicins A, B, E1, Ia, Ib, and N) are transmembrane proteins that depolarize the cytoplasmic membrane, leading to dissipation of cellular energy. These colicins contain at least three domains: an N-terminal translocation domain responsible for movement across the outer membrane and periplasmic space; a central domain responsible for receptor recognition; and a C-terminal cytotoxic domain responsible for channel formation in the cytoplasmic membrane. One domain regulates the target and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bacterial Conjugation
Bacterial conjugation is the transfer of genetic material between bacterial cells by direct cell-to-cell contact or by a bridge-like connection between two cells. This takes place through a pilus. It is a parasexual mode of reproduction in bacteria. It is a mechanism of horizontal gene transfer as are transformation and transduction although these two other mechanisms do not involve cell-to-cell contact. Classical ''E. coli'' bacterial conjugation is often regarded as the bacterial equivalent of sexual reproduction or mating since it involves the exchange of genetic material. However, it is not sexual reproduction, since no exchange of gamete occurs, and indeed no generation of a new organism: instead an existing organism is transformed. During classical ''E. coli'' conjugation the ''donor'' cell provides a conjugative or mobilizable genetic element that is most often a plasmid or transposon. Most conjugative plasmids have systems ensuring that the ''recipient'' cell does not al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
