|
Ansamycin
Ansamycins is a family of bacterial secondary metabolites that show antimicrobial activity against many Gram-positive and some Gram-negative bacteria, and includes various compounds, including streptovaricins and rifamycins. In addition, these compounds demonstrate antiviral activity towards bacteriophages and poxviruses. Structure They are named ansamycins (from the Latin ansa, ''handle'') because of their unique structure, which consists of an aromatic moiety bridged by an aliphatic chain. The main difference between various derivatives of ansamycins is the aromatic moiety, which can be a naphthalene ring or a naphthoquinone ring as in rifamycin and the naphthomycins. Another variation consists of benzene or a benzoquinone ring system as in geldanamycin or ansamitocin. Ansamycins were first discovered in 1959 by Sensi et al. from ''Amycolatopsis mediterranei'', an actinomycete bacterium. Examples Rifamycins are a subclass of ansamycins with high potency against mycobact ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ansamycins
Ansamycins is a family of bacterial secondary metabolites that show antimicrobial activity against many Gram-positive and some Gram-negative bacteria, and includes various compounds, including streptovaricins and rifamycins. In addition, these compounds demonstrate antiviral activity towards bacteriophages and poxviruses. Structure They are named ansamycins (from the Latin ansa, ''handle'') because of their unique structure, which consists of an aromatic moiety bridged by an aliphatic chain. The main difference between various derivatives of ansamycins is the aromatic moiety, which can be a naphthalene ring or a naphthoquinone ring as in rifamycin and the naphthomycins. Another variation consists of benzene or a benzoquinone ring system as in geldanamycin or ansamitocin. Ansamycins were first discovered in 1959 by Sensi et al. from ''Amycolatopsis mediterranei'', an actinomycete bacterium. Examples Rifamycins are a subclass of ansamycins with high potency against mycobacte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Naphthomycin
Naphthomycins are a group of closely related antimicrobial chemical compounds isolated from ''Streptomyces''. They are considered a subclass of ansamycin Ansamycins is a family of bacterial secondary metabolites that show antimicrobial activity against many Gram-positive and some Gram-negative bacteria, and includes various compounds, including streptovaricins and rifamycins. In addition, these ...s. Members include: * Naphthomycin A * Naphthomycin B * Naphthomycin C * Naphthomycin D * Naphthomycin E * Naphthomycin F * Naphthomycin G * Naphthomycin H * Naphthomycin I * Naphthomycin J * Naphthomycin K * Naphthomycin L * Naphthomycin M * Naphthomycin N Chemical structures File:Naphthomycin A.svg, Naphthomycin A File:Naphthomycin B.svg, Naphthomycin B File:Naphthomycin C.svg, Naphthomycin C File:Naphthomycin D.svg, Naphthomycin D File:Naphthomycin E.svg, Naphthomycin E File:Naphthomycin F.svg, Naphthomycin F File:Naphthomycin G.svg, Naphthomycin G References {{reflist Ant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyketides
Polyketides are a class of natural products derived from a precursor molecule consisting of a chain of alternating ketone (or reduced forms of a ketone) and methylene groups: (-CO-CH2-). First studied in the early 20th century, discovery, biosynthesis, and application of polyketides has evolved. It is a large and diverse group of secondary metabolites caused by its complex biosynthesis which resembles that of fatty acid synthesis. Because of this diversity, polyketides can have various medicinal, agricultural, and industrial applications. Many polyketides are medicinal or exhibit acute toxicity. Biotechnology has enabled discovery of more naturally-occurring polyketides and evolution of new polyketides with novel or improved bioactivity. History Naturally produced polyketides by various plants and organisms have been used by humans since before studies on them began in the 19th and 20th century. In 1893, J. Norman Collie synthesized detectable amounts of orcinol by heating dehy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geldanamycin
Geldanamycin is a 1,4-benzoquinone ansamycin antitumor antibiotic that inhibits the function of Hsp90 (Heat Shock Protein 90) by binding to the unusual ADP/ATP-binding pocket of the protein. HSP90 client proteins play important roles in the regulation of the cell cycle, cell growth, cell survival, apoptosis, angiogenesis and oncogenesis. Geldanamycin induces the degradation of proteins that are mutated or overexpressed in tumor cells such as v-Src, Bcr-Abl, p53, and ERBB2. This effect is mediated via HSP90. Despite its potent antitumor potential, geldanamycin presents several major drawbacks as a drug candidate such as hepatotoxicity, further, Jilani ''et al.''. reported that geldanamycin induces the apoptosis of erythrocytes under physiological concentrations. These side effects have led to the development of geldanamycin analogues, in particular analogues containing a derivatisation at the 17 position: * 17-AAG * 17-DMAG Biosynthesis Geldanamycin was originally discovered i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Streptovaricins
Streptovaricins are a group of structurally related macrolide antibiotics. They belong to the larger class of antibiotics known as ansamycin Ansamycins is a family of bacterial secondary metabolites that show antimicrobial activity against many Gram-positive and some Gram-negative bacteria, and includes various compounds, including streptovaricins and rifamycins. In addition, these ...s. References Macrolide antibiotics Ansamycins {{antibiotic-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geldanamycin
Geldanamycin is a 1,4-benzoquinone ansamycin antitumor antibiotic that inhibits the function of Hsp90 (Heat Shock Protein 90) by binding to the unusual ADP/ATP-binding pocket of the protein. HSP90 client proteins play important roles in the regulation of the cell cycle, cell growth, cell survival, apoptosis, angiogenesis and oncogenesis. Geldanamycin induces the degradation of proteins that are mutated or overexpressed in tumor cells such as v-Src, Bcr-Abl, p53, and ERBB2. This effect is mediated via HSP90. Despite its potent antitumor potential, geldanamycin presents several major drawbacks as a drug candidate such as hepatotoxicity, further, Jilani ''et al.''. reported that geldanamycin induces the apoptosis of erythrocytes under physiological concentrations. These side effects have led to the development of geldanamycin analogues, in particular analogues containing a derivatisation at the 17 position: * 17-AAG * 17-DMAG Biosynthesis Geldanamycin was originally discovered i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Poxviruses
''Poxviridae'' is a family of double-stranded DNA viruses. Vertebrates and arthropods serve as natural hosts. There are currently 83 species in this family, divided among 22 genera, which are divided into two subfamilies. Diseases associated with this family include smallpox. Four genera of poxviruses may infect humans: ''Orthopoxvirus'', ''Parapoxvirus'', ''Yatapoxvirus'', ''Molluscipoxvirus''. ''Orthopoxvirus'': smallpox virus (variola), vaccinia virus, cowpox virus, monkeypox virus; ''Parapoxvirus'': orf virus, pseudocowpox, bovine papular stomatitis virus; ''Yatapoxvirus'': tanapox virus, yaba monkey tumor virus; ''Molluscipoxvirus'': molluscum contagiosum virus (MCV). The most common are vaccinia (seen on the Indian subcontinent) and molluscum contagiosum, but monkeypox infections are rising (seen in west and central African rainforest countries). The similarly named disease chickenpox is not a true poxvirus and is caused by the herpesvirus varicella zoster. Etymology ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tuberculosis
Tuberculosis (TB) is an infectious disease usually caused by '' Mycobacterium tuberculosis'' (MTB) bacteria. Tuberculosis generally affects the lungs, but it can also affect other parts of the body. Most infections show no symptoms, in which case it is known as latent tuberculosis. Around 10% of latent infections progress to active disease which, if left untreated, kill about half of those affected. Typical symptoms of active TB are chronic cough with blood-containing mucus, fever, night sweats, and weight loss. It was historically referred to as consumption due to the weight loss associated with the disease. Infection of other organs can cause a wide range of symptoms. Tuberculosis is spread from one person to the next through the air when people who have active TB in their lungs cough, spit, speak, or sneeze. People with Latent TB do not spread the disease. Active infection occurs more often in people with HIV/AIDS and in those who smoke. Diagnosis of active TB is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ethers
In organic chemistry, ethers are a class of compounds that contain an ether group—an oxygen atom connected to two alkyl or aryl groups. They have the general formula , where R and R′ represent the alkyl or aryl groups. Ethers can again be classified into two varieties: if the alkyl or aryl groups are the same on both sides of the oxygen atom, then it is a simple or symmetrical ether, whereas if they are different, the ethers are called mixed or unsymmetrical ethers. A typical example of the first group is the solvent and anaesthetic diethyl ether, commonly referred to simply as "ether" (). Ethers are common in organic chemistry and even more prevalent in biochemistry, as they are common linkages in carbohydrates and lignin. Structure and bonding Ethers feature bent C–O–C linkages. In dimethyl ether, the bond angle is 111° and C–O distances are 141 pm. The barrier to rotation about the C–O bonds is low. The bonding of oxygen in ethers, alcohols, and water is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lactams
A lactam is a cyclic amide, formally derived from an amino alkanoic acid. The term is a portmanteau of the words ''lactone'' + ''amide''. Nomenclature Greek prefixes in alphabetical order indicate ring size: * α-Lactam (3-atom rings) * β-Lactam (4-atom rings) * γ-Lactam (5-atom rings) * δ-Lactam (6-atom rings) * ε-Lactam (7-atom rings) This ring-size nomenclature stems from the fact that a hydrolyzed α-Lactam leads to an α-amino acid and a β-Lactam to a β-amino acid, ''etc''. Synthesis General synthetic methods exist for the organic synthesis of lactams. Beckmann rearrangement Lactams form by the acid-catalyzed rearrangement of oximes in the Beckmann rearrangement. Schmidt reaction Lactams form from cyclic ketones and hydrazoic acid in the Schmidt reaction. Cyclization of amino acids Lactams can be formed from cyclisation of amino acids via the coupling between an amine and a carboxylic acid within the same molecule. Lactamization is most efficient in this wa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbamates
In organic chemistry, a carbamate is a category of organic compounds with the general formula and structure , which are formally derived from carbamic acid (). The term includes organic compounds (e.g., the ester ethyl carbamate), formally obtained by replacing one or more of the hydrogen atoms by other organic functional groups; as well as salts with the carbamate anion (e.g. ammonium carbamate). Polymers whose units are joined by carbamate groups are an important family of plastics, the polyurethanes. Properties While carbamic acids are unstable, many carbamate esters or ionic) are stable and well known. Equilibrium with carbonate and bicarbonate In water solutions, the carbamate anion slowly equilibrates with the ammonium cation and the carbonate or bicarbonate anions: : : Calcium carbamate is soluble in water, whereas calcium carbonate is not. Adding a calcium salt to an ammonium carbamate/carbonate solution will precipitate some calcium carbonate immediately, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.svg "Click for more on -> Ethers")
