Some antibiotics work by keeping translation from happening. Prokaryotic ribosomes are different from eukaryotic ribosomes. So antibiotics can kill bacteria without hurting the eukaryotic host. For example, antibiotics taken by a human might kill the bacteria that is making the human sick but wouldn't hurt the human.
Gene expression
Gene expression is the process by which the heritable information in a gene, the sequence of DNA base pairs, is made into a functional gene product, such as protein or RNA. The basic idea is that DNA is transcribed into RNA, which is then translated into proteins. Proteins make many of the structures and all the enzymes in a cell or organism.
Several steps in the gene expression process may be modulated (tuned). This includes both the transcription and translation stages, and the final folded state of a protein. Gene regulation switches genes on and off, and so controls cell differentiation, and morphogenesis. Gene regulation may also serve as a basis for evolutionary change: control of the timing, location, and amount of gene expression can have a profound effect on the development of the organism.
The expression of a gene may vary a lot in different tissues. This is called pleiotropism, a widespread phenomenon in genetics.
In biology, epigenetics is the study of inherited changes in phenotype (appearance) or gene expression caused by mechanisms other than changes in the underlying DNA sequence.
These changes may remain through cell divisions for the remainder of the individual's life and may also last for multiple generations. However, "there is no change in the underlying DNA sequence of the organism". Instead, non-genetic factors cause the organism's genes to behave (express themselves) differently.
The best example of epigenetic changes in eukaryote biology is the process of cellular differentiation. During morphogenesis, totipotent stem cells become the various cell lines of the embryo, which in turn become fully differentiated cells. In other words, a single fertilized egg cell – the zygote – divides and develops. The daughter cells change into the many cell types of the mature embryo. These include neurones, muscle cells, epithelium, blood vessels an so on. This happens by activating some genes while inhibiting others.
Epigenetic changes are long-term, and usually survive the process of cell division (mitosis). Changes occur in the chromatin, which is a combination of the DNA and its surrounding histone proteins in the chromosome. The details of how this happens are still being worked out, but it is fairly certain that the wrapping of the DNA and histone is a key feature.
Up-regulation increases the expression of one or more genes and as a result the protein(s) encoded by those genes. Down-regulation is a process resulting in decreased gene and protein expression.
Gene regulation can be summarized as:
There are a number of RNAs which regulate genes, that is, they regulate the rate at which genes are transcribed or translated. The following are two important examples
Micro RNAs (miRNA) act by joining an enzyme and blocking mRNA (messenger RNA), or speeding its breakdown. This is called RNA interference.
Small interfering RNAs (sometimes called silencing RNAs) interfere with the expression of a specific gene. They are quite small (20/25 nucleotides) double-stranded molecules. Their discovery has caused a surge in biomedical research and drug development.
Curtis (50 Cent album)
Curtis is the third album by rapper 50 Cent. The album was released on September 11, 2007. The album features production from Dr. Dre, Eminem, and Timbaland, among others. Guest appearances include Akon, Justin Timberlake, Nicole Scherzinger, and other notable musicians. 50 Cent divides between "hard" songs and "soft" songs on the album.
"Curtis" was released and sold 691,000 copies in its first week on the "Billboard" 200. It sold the most copies in one week for an East Coast album since Jay-Z's "Kingdom Come" sold 680,000 copies sold. The album's sales competition with Kanye West's "Graduation" was considered to be a "great day for hip hop".
Šarplaninac
The Šarplaninac (pronounced shar-pla-NEE-natz) (also known as Sharplaninec) is a large-sized shepherd dog breed of the Balkan region, from the Šar mountains ("Šar Planina" in Serbian and Macedonian or "Bjeshket e Sharrit" in Albanian).
El Limón, Samaná
El Limón (in English, "The Lemon") is a Municipal district of Santa Bárbara de Samaná, Samaná province, Dominican Republic. It is on the north coast of the Samaná Peninsula, on the Atlantic coast.
It was made a municipal district on July 20, 2001.
There are other two Municipal districts with the same name (El Limón) in the country: one in the Independencia province and the other in the Santiago province.
Théodore Chassériau, a French painter, was born in El Limón on 1819.
In the last national census (2010), the district had a total population of 7,024: 3,622 men and 3,402 women. The urban population was 66.23% of the total population.
The most important economic activities of the province are agriculture, fishing and tourism. Tourism, above all nature tourism, is important here because many tourists visit El Limón Waterfall.
Théodore Chassériau
Théodore Chassériau (September 20, 1819 – October 8, 1856) was a French romantic painter noted for his portraits, historical and religious paintings, and images inspired by his travels to Algeria.
Chassériau was born in El Limón, Samaná, in "Saint Domingue" (now the Dominican Republic). Her mother, Maria Magdalena Couret de la Blagniére, was born in Haiti but she moved with her parents to Santo Domingo when the Haitian revolution. At that time, the eastern part of Hispaniola was a French colony. There she met Bénoit Chassériau and soon they got married and moved to Samaná.
When the eastern part of the Hispaniola became again a colony of Spain, the family moved to Venezuela and Jamaica. Then, in 1821, the family went to live in Paris, France. Théodore was three years old at that time.
In 1830, at the age of eleven, he started to study with Jean-Auguste-Dominique Ingres, and soon he became the favorite pupil of the great classicist.
After Ingres left Paris in 1834 to become director of the French Academy in Rome, Chassériau fell under the influence of Eugène Delacroix, a well-known romantic painter. From that moment on, Chassériau tried to combine the two styles.
His works could be grouped in two periods:
Chassériau died when he was 37 years old in Paris, on October 8, 1856.
Théodore Chassériau exhibition at the Metropolitan Museum of Art Retrieved on 2007-10-03.
Intermolecular force
In physics, chemistry, and biology, intermolecular forces are forces that act between stable molecules or between functional groups of macromolecules.
These forces are generally much weaker than the chemical bonding forces. Their bonding energies are less than a few kcal/mol. But they are responsible for many different physical, chemical, and biological phenomena. In general one distinguishes short and long range intermolecular forces.
Hydrogen bonding is an intermolecular interaction with a hydrogen atom being present in the intermolecular bond.
Spineshank
SpineShank is a alernative metal band formed in Los Angeles in 1996. They released four albums under Roadrunner Records:
Tanystropheus
Tanystropheus is a long necked reptile that lived in the Middle Triassic period. The main feature that stands out about this animal is its very long neck. Fossils of this creature have been found in Europe and the Middle East. Habitat: probably aquatic.
Yuryuzan, Chelyabinsk Oblast
Yuryuzan () is a town in Chelyabinsk Oblast, Russia. Its population is near 13,700 ().
Yuryuzan is located on Yuryuzan River's bank.
Sim (town)
Sim (, 54°59'N 57°41'E) is town in Chelyabinsk Oblast, Russia. Its population is near 15,900 (2005).
Sim is located on Sim River's bank. Town was founded in 1759 and named "Simsky Zavod" until 1942.