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Male Sterility
Cytoplasmic male sterility is total or partial male sterility in hermaphrodite organisms, as the result of specific nuclear and mitochondrial interactions. Male sterility is the failure to produce functional anthers, pollen, or male gametes. Such male sterility in hermaphrodite populations leads to gynodioecious populations (populations with coexisting fully functioning hermaphrodites and male-sterile hermaphrodites). Cytoplasmic male sterility, as the name indicates, is under extranuclear genetic control (under control of the mitochondrial or plastid genomes). It shows non-Mendelian inheritance, with male sterility inherited maternally. In general, there are two types of cytoplasm: N (normal) and aberrant S (sterile) cytoplasms. These types exhibit reciprocal differences. History Joseph Gottlieb Kölreuter was the first to document male sterility in plants. In the 18th century, he reported on anther abortion within species and specific hybrids. Cytoplasmic male sterility (CMS ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cell Nucleus
The cell nucleus (; : nuclei) is a membrane-bound organelle found in eukaryote, eukaryotic cell (biology), cells. Eukaryotic cells usually have a single nucleus, but a few cell types, such as mammalian red blood cells, have #Anucleated_cells, no nuclei, and a few others including osteoclasts have Multinucleate, many. The main structures making up the nucleus are the nuclear envelope, a double membrane that encloses the entire organelle and isolates its contents from the cellular cytoplasm; and the nuclear matrix, a network within the nucleus that adds mechanical support. The cell nucleus contains nearly all of the cell's genome. Nuclear DNA is often organized into multiple chromosomes – long strands of DNA dotted with various proteins, such as histones, that protect and organize the DNA. The genes within these chromosomes are Nuclear organization, structured in such a way to promote cell function. The nucleus maintains the integrity of genes and controls the activities of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mitochondria
A mitochondrion () is an organelle found in the cells of most eukaryotes, such as animals, plants and fungi. Mitochondria have a double membrane structure and use aerobic respiration to generate adenosine triphosphate (ATP), which is used throughout the cell as a source of chemical energy. They were discovered by Albert von Kölliker in 1857 in the voluntary muscles of insects. The term ''mitochondrion'', meaning a thread-like granule, was coined by Carl Benda in 1898. The mitochondrion is popularly nicknamed the "powerhouse of the cell", a phrase popularized by Philip Siekevitz in a 1957 ''Scientific American'' article of the same name. Some cells in some multicellular organisms lack mitochondria (for example, mature mammalian red blood cells). The multicellular animal '' Henneguya salminicola'' is known to have retained mitochondrion-related organelles despite a complete loss of their mitochondrial genome. A large number of unicellular organisms, such as microspo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Southern Corn Leaf Blight
Southern corn leaf blight (SCLB) is a fungal disease of maize caused by the plant pathogen '' Bipolaris maydis'' (also known as '' Cochliobolus heterostrophus'' in its teleomorph state). The fungus is an Ascomycete and can use conidia or ascospores to infect. There are three races of ''B. maydis'': Race O, Race C, and Race T; SCLB symptoms vary depending on the infectious pathogen's race. Race T is infectious to corn plants with the Texas male sterile cytoplasm (cms-T maize) and this vulnerability was the cause of the United States SCLB epidemic of 1969-19701 Ullstrup, A. J., ''Annual Review of Phytopathology'' 10 (1), 37 (1972). For this reason, Race T is of particular interest. While SCLB thrives in warm, damp climates, the disease can be found in many of the world's maize-growing areas. Typical management practices include breeding for host resistance, cultural controls and fungicide use. Hosts The primary host for Southern corn leaf blight is ''Zea mays'', or maize, k ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Detasseling
Detasseling corn is removing the pollen-producing flowers, the tassel, from the tops of corn (maize) plants and placing them on the ground. It is a form of pollination control, Iowa State University. Retrieved October 12, 2009. employed to cross-breed, or hybridize, two varieties of corn. Fields of corn that will be detasseled are planted with two varieties of corn. Removing the tassels from all the plants of one variety leaves the grain that is growing on those plants to be fertilized by the tassels of the other, resulting in a hybrid. In addition to being more physically uniform, hybrid corn produces dramatically higher yields than corn produced by open pollination. With modern seed corn, the varieties to hybridize are carefully ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maize
Maize (; ''Zea mays''), also known as corn in North American English, is a tall stout grass that produces cereal grain. It was domesticated by indigenous peoples in southern Mexico about 9,000 years ago from wild teosinte. Native Americans planted it alongside beans and squashes in the Three Sisters polyculture. The leafy stalk of the plant gives rise to male inflorescences or tassels which produce pollen, and female inflorescences called ears. The ears yield grain, known as kernels or seeds. In modern commercial varieties, these are usually yellow or white; other varieties can be of many colors. Maize relies on humans for its propagation. Since the Columbian exchange, it has become a staple food in many parts of the world, with the total production of maize surpassing that of wheat and rice. Much maize is used for animal feed, whether as grain or as the whole plant, which can either be baled or made into the more palatable silage. Sugar-rich varieties called sw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
F1 Generation
F1 hybrid (also known as filial 1 hybrid) is the first filial generation of offspring of distinctly different parental types. F1 hybrids are used in genetics, and in selective breeding, where the term F1 crossbreed may be used. The term is sometimes written with a subscript, as F hybrid. Subsequent generations are called F, F, etc. The offspring of distinctly different parental types produce a new, uniform phenotype with a combination of characteristics from the parents. In fish breeding, those parents frequently are two closely related fish species; however, in plant and animal breeding, the parents often are two inbred lines. Gregor Mendel focused on patterns of inheritance and the genetic basis for variation. In his cross-pollination experiments involving two true-breeding, or homozygous, parents, Mendel found that the resulting F1 generation was heterozygous and consistent. The offspring showed a combination of the phenotypes from each parent that were genetically dominant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Emasculation
Emasculation is the removal of the external male sex organs, which includes both the penis and the scrotum, the latter of which contains the testicles. It is distinct from castration, where only the testicles are removed. Although the terms are sometimes used interchangeably, the potential medical consequences of emasculation are more extensive due to the complications arising from the removal of the penis. There are a range of religious, cultural, punitive, and personal reasons why someone may choose to emasculate themselves or another person. The term ''emasculation'' may be used in a metaphorical sense, referring to the perceived loss of attributes traditionally associated with masculinity, such as strength, power, or autonomy. Method There are several different methods of emasculation. Both the penis and testicles may be removed simultaneously using a sharp instrument, such as a knife or razor or swords. Non-crushing vascular clamps may also be used in medical surgery to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monsanto
The Monsanto Company () was an American agrochemical and agricultural biotechnology corporation founded in 1901 and headquartered in Creve Coeur, Missouri. Monsanto's best-known product is Roundup, a glyphosate-based herbicide, developed in the 1970s. Later, the company became a major producer of genetically engineered crops. In 2018, the company ranked 199th on the Fortune 500 of the largest United States corporations by revenue. Monsanto was one of four groups to introduce genes into plants in 1983, and was among the first to conduct field trials of genetically modified crops in 1987. It was one of the top-ten U.S. chemical companies until it divested most of its chemical businesses between 1997 and 2002, through a process of mergers and spin-offs that focused the company on biotechnology. Monsanto was one of the first companies to apply the biotechnology industry business model to agriculture, using techniques developed by biotech drug companies. In this business m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pioneer Hi Bred International
Pioneer Hi-Bred International, Inc., a subsidiary of Corteva, is a U.S.-based producer of seeds for agriculture. It is a major producer of genetically modified crops with insect and herbicide resistance. History In 1926, farm journal editor and future U.S. Vice President Henry A. Wallace, along with a group of Des Moines, Iowa businessmen, founded the Hi-Bred Corn Company. The group included Henry's brother James W. Wallace, Fred Lehmann, J. J. Newlin, Simon Casady Jr. and George Kurtzweil. Wallace had been experimenting with hybridization of corn and became convinced that hybrid seed corn would become important. Several generations of the Casady family were shareholders or officers at Pioneer, including Simon Casady Jr.'s son Simon Wheeler Casady III, who was a Pioneer director, secretary, and major shareholder. Simon Casady Jr.'s wife Grace Margaret Wheeler Casady was also a major shareholder. Simon and Grace's daughters Hortense Oldfather and Rose Casady McCay were also s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Barnase
Barnase (a portmanteau of "BActerial" "RiboNucleASE") is a bacterial protein that consists of 110 amino acids and has ribonuclease activity. It is synthesized and secreted by the bacterium '' Bacillus amyloliquefaciens'', but is lethal to the cell when expressed without its inhibitor barstar. The inhibitor binds to and occludes the ribonuclease active site, preventing barnase from damaging the cell's RNA after it has been synthesized but before it has been secreted. The barnase/barstar complex is noted for its extraordinarily tight protein-protein binding, with an on-rate of 108s−1M−1. Protein folding studies Barnase has no disulfide bonds, nor does it require divalent cations or non-peptide components to fold. This simplicity, in combination with its reversible folding transition, means that barnase has been extensively studied in order to understand how proteins fold. The folding of barnase has been extensively studied in the laboratory of Alan Fersht, who used it as t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genotype
The genotype of an organism is its complete set of genetic material. Genotype can also be used to refer to the alleles or variants an individual carries in a particular gene or genetic location. The number of alleles an individual can have in a specific gene depends on the number of copies of each chromosome found in that species, also referred to as ploidy. In diploid species like humans, two full sets of chromosomes are present, meaning each individual has two alleles for any given gene. If both alleles are the same, the genotype is referred to as Zygosity, homozygous. If the alleles are different, the genotype is referred to as heterozygous. Genotype contributes to phenotype, the observable traits and characteristics in an individual or organism. The degree to which genotype affects phenotype depends on the trait. For example, the petal color in a pea plant is exclusively determined by genotype. The petals can be purple or white depending on the alleles present in the pea plan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iodine
Iodine is a chemical element; it has symbol I and atomic number 53. The heaviest of the stable halogens, it exists at standard conditions as a semi-lustrous, non-metallic solid that melts to form a deep violet liquid at , and boils to a violet gas at . The element was discovered by the French chemist Bernard Courtois in 1811 and was named two years later by Joseph Louis Gay-Lussac, after the Ancient Greek , meaning 'violet'. Iodine occurs in many oxidation states, including iodide (I−), iodate (), and the various periodate anions. As the heaviest essential mineral nutrient, iodine is required for the synthesis of thyroid hormones. Iodine deficiency affects about two billion people and is the leading preventable cause of intellectual disabilities. The dominant producers of iodine today are Chile and Japan. Due to its high atomic number and ease of attachment to organic compounds, it has also found favour as a non-toxic radiocontrast material. Because of the spec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
