|
Halobacterium Noricense
''Halobacterium noricense'' is a halophilic, rod-shaped microorganism that thrives in environments with salt levels near saturation. Despite the implication of the name, ''Halobacterium'' is actually a genus of archaea, not bacteria. ''H. noricense'' can be isolated from environments with high salinity such as the Dead Sea and the Great Salt Lake in Utah. Members of the ''Halobacterium'' genus are excellent model organisms for DNA replication and transcription due to the stability of their proteins and polymerases when exposed to high temperatures. To be classified in the genus ''Halobacterium'', a microorganism must exhibit a membrane composition consisting of ether-linked phosphoglycerides and glycolipids. Scientific classification This organism is a member of the genus ''Halobacterium'' and its taxonomic classification is as follows: Archaea, Euryarchaeota, Euryarchaeota, Halobacteria, Halobacteriales, Halobacteriaceae, Halobacterium, ''Halobacterium noricense.'' There are cu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archaea
Archaea ( ; singular archaeon ) is a domain of single-celled organisms. These microorganisms lack cell nuclei and are therefore prokaryotes. Archaea were initially classified as bacteria, receiving the name archaebacteria (in the Archaebacteria kingdom), but this term has fallen out of use. Archaeal cells have unique properties separating them from the other two domains, Bacteria and Eukaryota. Archaea are further divided into multiple recognized phyla. Classification is difficult because most have not been isolated in a laboratory and have been detected only by their gene sequences in environmental samples. Archaea and bacteria are generally similar in size and shape, although a few archaea have very different shapes, such as the flat, square cells of ''Haloquadratum walsbyi''. Despite this morphological similarity to bacteria, archaea possess genes and several metabolic pathways that are more closely related to those of eukaryotes, notably for the enzymes involved ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multilocus Sequence Typing
Multilocus sequence typing (MLST) is a technique in molecular biology for the typing of multiple loci, using DNA sequences of internal fragments of multiple housekeeping genes to characterize isolates of microbial species. The first MLST scheme to be developed was for ''Neisseria meningitidis'', the causative agent of meningococcal meningitis and septicaemia. Since its introduction for the research of evolutionary history, MLST has been used not only for human pathogens but also for plant pathogens. Principle MLST directly measures the DNA sequence variations in a set of housekeeping genes and characterizes strains by their unique allelic profiles. The principle of MLST is simple: the technique involves PCR amplification followed by DNA sequencing. Nucleotide differences between strains can be checked at a variable number of genes depending on the degree of discrimination desired. The workflow of MLST involves: 1) data collection, 2) data analysis and 3) multilocus sequence ana ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GC-content
In molecular biology and genetics, GC-content (or guanine-cytosine content) is the percentage of nitrogenous bases in a DNA or RNA molecule that are either guanine (G) or cytosine (C). This measure indicates the proportion of G and C bases out of an implied four total bases, also including adenine and thymine in DNA and adenine and uracil in RNA. GC-content may be given for a certain fragment of DNA or RNA or for an entire genome. When it refers to a fragment, it may denote the GC-content of an individual gene or section of a gene (domain), a group of genes or gene clusters, a non-coding region, or a synthetic oligonucleotide such as a primer. Structure Qualitatively, guanine (G) and cytosine (C) undergo a specific hydrogen bonding with each other, whereas adenine (A) bonds specifically with thymine (T) in DNA and with uracil (U) in RNA. Quantitatively, each GC base pair is held together by three hydrogen bonds, while AT and AU base pairs are held together by two hydrogen bonds. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mesophile
A mesophile is an organism that grows best in moderate temperature, neither too hot nor too cold, with an optimum growth range from . The optimum growth temperature for these organisms is 37°C. The term is mainly applied to microorganisms. Organisms that prefer extreme environments are known as extremophiles. Mesophiles have diverse classifications, belonging to two domains: Bacteria, Archaea, and to kingdom Fungi of domain Eucarya. Mesophiles belonging to the domain Bacteria can either be gram-positive or gram-negative. Oxygen requirements for mesophiles can be aerobic or anaerobic. There are three basic shapes of mesophiles: coccus, bacillus, and spiral. Habitat The habitats of mesophiles can include cheese and yogurt. They are often included during fermentation of beer and wine making. Since normal human body temperature is 37 °C, the majority of human pathogens are mesophiles, as are most of the organisms comprising the human microbiome. Mesophiles vs. extremophiles Meso ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Incubation Period
Incubation period (also known as the latent period or latency period) is the time elapsed between exposure to a pathogenic organism, a chemical, or radiation, and when symptoms and signs are first apparent. In a typical infectious disease, the incubation period signifies the period taken by the multiplying organism to reach a threshold necessary to produce symptoms in the host. While ''latent'' or ''latency period'' may be synonymous, a distinction is sometimes made whereby the latent period is defined as the time from infection to infectiousness. Which period is shorter depends on the disease. A person may carry disease, such as ''Streptococcus'' in the throat, without exhibiting any symptoms. Depending on the disease, the person may or may not be contagious during the incubation period. During latency, an infection is subclinical. With respect to viral infections, in incubation the virus is replicating. This is in contrast to viral latency, a form of dormancy in which the v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tryptone
Tryptone is the assortment of peptides formed by the digestion of casein by the protease trypsin. Tryptone is commonly used in microbiology to produce lysogeny broth (LB) for the growth of '' E. coli'' and other microorganisms. It provides a source of amino acids for the growing bacteria. Tryptone is similar to casamino acids, both being digests of casein, but casamino acids can be produced by acid hydrolysis and typically only have free amino acids and few peptide chains; tryptone by contrast is the product of an incomplete enzymatic hydrolysis with some oligopeptides present. Tryptone is also a component of some germination media used in plant propagation.Pierik, R. L. M., et al. (1988)Seed germination and further development of plantlets of ''Paphiopedilum ciliolare'' Pfitz. ''in vitro''.''Scientia Horticulturae'', 34(1), 139-153. See also * Albumose *Trypticase soy agar Trypticase soy agar or tryptone soya agar (TSA) and Trypticase soy broth or tryptone soya broth (TS ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yeast Extract Agar
Yeast extract agar is a growth medium containing yeast extract. It may refer to: * The nonselective yeast extract agar of Windle Taylor * YM (selective medium), for yeasts and molds * Buffered charcoal yeast extract agar Buffered charcoal yeast extract (BCYE) agar is a selective growth medium used to culture or grow certain types of bacteria, particularly the Gram-negative species ''Legionella pneumophila''. It has also been used for the laboratory diagnosis of ..., for '' Legionella'' {{set index ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ATCC (company)
ATCC or the American Type Culture Collection is a nonprofit organization which collects, stores, and distributes standard reference microorganisms, cell lines and other materials for research and development. Established in 1925 to serve as a national center for depositing and distributing microbiological specimens, ATCC has since grown to distribute in over 150 countries.Clark, W.A. and D. H. Geary. 1974. The Story of the American Type Culture Collection – Its History and Development (1899-1973). Advances in Applied Microbiology 17:295-309. It is now the largest general culture collection in the world. Products and collections ATCC's collections include a wide range of biological materials for research, including cell lines, microorganisms and bioproducts. The organization holds a collection of more than 3,000 human and animal cell lines and an additional 1,200 hybridomas. ATCC's microorganism collection includes a collection of more than 18,000 strains of bacteria, as well as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Core Drill
A modern core drill is a drill specifically designed to remove a cylinder of material, much like a hole saw. The material left inside the drill bit is referred to as the ''core''. Core drills used in metal are called annular cutters. Core drills used for concrete and hard rock generally use industrial diamond grit as the abrasive material and may be electrical, pneumatic or hydraulic powered. Core drills are commonly water cooled, and the water also carries away the fine waste as a slurry. For drilling masonry, carbide core drills can be used, but diamond is more successful when cutting through rebar. The earliest core drills were those used by the ancient Egyptians, invented in 3000 BC. Core drills are used for many applications, either where the core needs to be preserved (the drilling apparatus used in obtaining a core sample is often referred to as a corer), or where drilling can be done more rapidly since much less material needs to be removed than with a standard bit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Permian
The Permian ( ) is a geologic period and stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last period of the Paleozoic Era; the following Triassic Period belongs to the Mesozoic Era. The concept of the Permian was introduced in 1841 by geologist Sir Roderick Murchison, who named it after the region of Perm in Russia. The Permian witnessed the diversification of the two groups of amniotes, the synapsids and the sauropsids ( reptiles). The world at the time was dominated by the supercontinent Pangaea, which had formed due to the collision of Euramerica and Gondwana during the Carboniferous. Pangaea was surrounded by the superocean Panthalassa. The Carboniferous rainforest collapse left behind vast regions of desert within the continental interior. Amniotes, which could better cope with these drier conditions, rose to dominance in place of their am ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salt Deposit
Salt mining extracts natural salt deposits from underground. The mined salt is usually in the form of halite (commonly known as rock salt), and extracted from evaporite formations. History Before the advent of the modern internal combustion engine and earth-moving equipment, mining salt was one of the most expensive and dangerous of operations because of rapid dehydration caused by constant contact with the salt (both in the mine passages and scattered in the air as salt dust) and of other problems caused by accidental excessive sodium intake. Salt is now plentiful, but until the Industrial Revolution, it was difficult to come by, and salt was often mined by slaves or prisoners. Life expectancy for the miners was low. Ancient China was among the earliest civilizations in the world with cultivation and trade in mined salt. They first discovered natural gas when they excavated rock salt. The Chinese writer, poet, and politician Zhang Hua of the Jin dynasty wrote in his book ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gram-negative Bacteria
Gram-negative bacteria are bacteria that do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. They are characterized by their cell envelopes, which are composed of a thin peptidoglycan cell wall sandwiched between an inner cytoplasmic cell membrane and a bacterial outer membrane. Gram-negative bacteria are found in virtually all environments on Earth that support life. The gram-negative bacteria include the model organism ''Escherichia coli'', as well as many pathogenic bacteria, such as ''Pseudomonas aeruginosa'', '' Chlamydia trachomatis'', and ''Yersinia pestis''. They are a significant medical challenge as their outer membrane protects them from many antibiotics (including penicillin), detergents that would normally damage the inner cell membrane, and lysozyme, an antimicrobial enzyme produced by animals that forms part of the innate immune system. Additionally, the outer leaflet of this membrane comprises a complex lipopol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.jpg "Click for more on -> Archaea")
