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Streptogramin B
Streptogramin B is a subgroup of the streptogramin antibiotics family. These natural products are cyclic hexa- or hepta depsipeptides produced by various members of the genus of bacteria ''Streptomyces''. Many of the members of the streptogramins reported in the literature have the same structure and different names; for example, pristinamycin IA = vernamycin Bα = mikamycin B = osteogrycin B. Biosynthesis The biosynthesis of streptogramin B is carried out by large multifunctional enzymes called non-ribosomal peptide synthetases (NRPS). In the NRPS system, each amino acid is activated as an aminoacyladenylate and is linked to the enzyme as a thioester with a phosphopantetheinyl group. An elongation reaction then occurs by transferring the activated carboxyl to the amino group in the next amino acid, thus executing the N-to-C stepwise condensation. NRPSs contain several modules on a single polypeptide. Each of these modules can catalyze activation, condensation and a modification re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Streptogramin
Streptogramins are a class of antibiotics. Streptogramins are effective in the treatment of vancomycin-resistant ''Staphylococcus aureus'' (VRSA) and vancomycin-resistant ''Enterococcus'' (VRE), two of the most rapidly growing strains of multidrug-resistant bacteria. They fall into two groups: streptogramin A and streptogramin B. Members include: * Quinupristin/dalfopristin * Pristinamycin Pristinamycin ( INN), also spelled pristinamycine, is an antibiotic used primarily in the treatment of staphylococcal infections, and to a lesser extent streptococcal infections. It is a streptogramin group antibiotic, similar to virginiamycin, ... * Virginiamycin * NXL 103, an experimental streptogramin in clinical trials for the treatment of respiratory tract infections. References Antibiotics {{antibiotic-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gram Positive
In bacteriology, gram-positive bacteria are bacteria that give a positive result in the Gram stain test, which is traditionally used to quickly classify bacteria into two broad categories according to their type of cell wall. Gram-positive bacteria take up the crystal violet stain used in the test, and then appear to be purple-coloured when seen through an optical microscope. This is because the thick peptidoglycan layer in the bacterial cell wall retains the stain after it is washed away from the rest of the sample, in the decolorization stage of the test. Conversely, gram-negative bacteria cannot retain the violet stain after the decolorization step; alcohol used in this stage degrades the outer membrane of gram-negative cells, making the cell wall more porous and incapable of retaining the crystal violet stain. Their peptidoglycan layer is much thinner and sandwiched between an inner cell membrane and a bacterial outer membrane, causing them to take up the counterstain (s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synercid
Quinupristin/dalfopristin, or quinupristin-dalfopristin, (pronunciation: kwi NYOO pris tin / dal FOE pris tin) (trade name Synercid) is a combination of two antibiotics used to treat infections by staphylococci and by vancomycin-resistant ''Enterococcus faecium''. Quinupristin and dalfopristin are both streptogramin antibiotics, derived from pristinamycin. Quinupristin is derived from pristinamycin IA; dalfopristin from pristinamycin IIA. They are combined in a weight-to-weight ratio of 30% quinupristin to 70% dalfopristin. Administration Intravenous, usually 7.5 mg/kg every 8 hours (infections/life threatening VRSA); every 12 hours (skin infections). No renal dosing adjustments, hepatic dosing adjustments are not defined, consider reducing dose. Mechanism of action Quinupristin and dalfopristin are protein synthesis inhibitors in a synergistic manner. While each of the two is only a bacteriostatic agent, the combination shows bactericidal activity. *Dalfopristin binds ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dalfopristin
Dalfopristin is a semi-synthetic streptogramin antibiotic analogue of ostreogyrcin A ( virginiamycin M, pristinamycin IIA, streptogramin A). The combination quinupristin/dalfopristin (marketed under the trade name Synercid) was brought to the market by Rhone-Poulenc Rorer Pharmaceuticals in 1999. Synercid (weight-to-weight ratio of 30% quinupristin to 70% dalfopristin) is used to treat infections by staphylococci and by vancomycin-resistant ''Enterococcus faecium''. Synthesis Through the addition of diethylaminoethylthiol to the 2-pyrroline group and oxidation of the sulfate of ostreogrycin A, a structurally more hydrophobic compound is formed. This hydrophobic compound contains a readily ionizable group that is available for salt formation. Large Scale Preparation Dalfopristin is synthesized from pristinamycine IIa through achieving a stereoselective Michael-type addition of 2-diethylaminoethanethiol on the conjugated double bond of the dehydroproline ring . The fir ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quinupristin
{{Drugbox , IUPAC_name = ''N''-{(6''R'',9''S'',10''R'',13''S'',15a''S'',18''R'',22''S'',24a''S'')-18- { 3''S'')-1-azabicyclo[2.2.2ct-3-ylthio">.2.2.html" ;"title="3''S'')-1-azabicyclo[2.2.2">3''S'')-1-azabicyclo[2.2.2ct-3-ylthioethyl}-22-[4-(dimethylamino)benzyl]- 6-ethyl-10,23-dimethyl-5,8,12,15,17,21,24-heptaoxo-13-phenyldocosahydro-12''H''- pyrido[2,1-''f'']pyrrolo-[2,1-''l''][1,4,7,10,13,16] oxapentaazacyclononadecin-9-yl}-3- hydroxypyridine-2-carboxamide , image = Quinupristin.png , CAS_number = 120138-50-3 , UNII_Ref = {{fdacite, correct, FDA , UNII = 23OW28RS7P , ATC_prefix = , ATC_suffix = , PubChem = 5388937 , DrugBank = , ChEMBL = 1200649 , ChemSpiderID = 4470884 , smiles = CC @@HC(=O)N2CCC @HC(=O)N( @HC(=O)N3C @HC(=O)C @HC(=O)N @HC(=O)O @@H @@HC(=O)N1)NC(=O)C4=C(C=CC=N4)O)C)C5=CC=CC=C5)CS @@HCN7CCC6CC7)CC8=CC=C(C=C8)N(C)C)C , StdInChI = 1S/C53H67N9O10S/c1-6-37-50(6 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pristinamycin IIA
Pristinamycin IIA is a macrolide antibiotic. It is a member of the streptogramin A group of antibiotics and one component of pristinamycin (the other being pristinamycin IA). Pristinamycin IIA was first isolated from the Streptomyces virginiae, but has been isolated from other microorganisms and thus has been given a variety of other names such as Virginiamycin M1, Mikamycin A, and Streptogramin A. Pristinamycin IIA structure was determined by chemical and instrumental techniques, including X-ray crystallography. Pristinamycin IIA is of interest from a biosynthetic viewpoint because it contains the unusual dehydroproline and oxazole ring systems. The only experimental evidence bearing on the formation of the oxazole ring is found in work on the biosynthesis of the alkaloid annuloline. __TOC__ Biosynthesis Pristinamycin IIA biosynthesis is presumed to proceed through the acetate pathway and was determined through the feeding of 3H and 13C precursors to Streptomyces virginiae ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multidrug-resistant Bacteria
Multidrug-resistant bacteria (MDR bacteria) are bacteria that are resistant to three or more classes of antimicrobial drugs. MDR bacteria have seen an increase in prevalence in recent years and pose serious risks to public health. MDR bacteria can be broken into 3 main categories: Gram-positive, Gram-negative, and other ( acid-stain). These bacteria employ various adaptations to avoid or mitigate the damage done by antimicrobials. With increased access to modern medicine there has been a sharp increase in the amount of antibiotics consumed. Given the abundant use of antibiotics there has been a considerable increase in the evolution of antimicrobial resistance factors, now outpacing the development of new antibiotics. Examples identified as serious threats to public health Examples of MDR bacteria identified as serious threats to public health include: ;Gram-positive MDR bacteria * ''Clostridioides difficile'' * '' Staphylococcus aureus'' * ''Streptococcus pneumoniae'' ;Gram-nega ... [...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 lipo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyclization Streptogramin B
A cyclic compound (or ring compound) is a term for a compound in the field of chemistry in which one or more series of atoms in the compound is connected to form a ring. Rings may vary in size from three to many atoms, and include examples where all the atoms are carbon (i.e., are carbocycles), none of the atoms are carbon (inorganic cyclic compounds), or where both carbon and non-carbon atoms are present (heterocyclic compounds). Depending on the ring size, the bond order of the individual links between ring atoms, and their arrangements within the rings, carbocyclic and heterocyclic compounds may be aromatic or non-aromatic; in the latter case, they may vary from being fully saturated to having varying numbers of multiple bonds between the ring atoms. Because of the tremendous diversity allowed, in combination, by the valences of common atoms and their ability to form rings, the number of possible cyclic structures, even of small size (e.g., < 17 total atoms) numbers in the many ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Depsipeptides
A depsipeptide is a peptide in which one or more of its amide, -C(O)NHR-, groups are replaced by the corresponding ester, -C(O)OR, Many depsipeptides have both peptide and ester linkages. Elimination of the N–H group in a peptide structure results in a decrease of H-bonding capability, which is responsible for secondary structure and folding patterns of peptides, thus inducing structural deformation of the helix and b-sheet structures. Because of decreased resonance delocalization in esters relative to amides, depsipeptides have lower rotational barriers for cis-trans isomerization and therefore they have more flexible structures than their native analogs. They are mainly found in marine and microbial natural products. Depsipeptide natural products 222px, Enterochelin is a depsipeptide that is an iron-transporter. Several depsipeptides have been found to exhibit anti-cancer properties. A depsipeptide enzyme inhibitor includes romidepsin, a member of the bicyclic peptide class, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Streptogramin B (modules)
Streptogramin B is a subgroup of the streptogramin antibiotics family. These natural products are cyclic hexa- or hepta depsipeptides produced by various members of the genus of bacteria '' Streptomyces''. Many of the members of the streptogramins reported in the literature have the same structure and different names; for example, pristinamycin IA = vernamycin Bα = mikamycin B = osteogrycin B. Biosynthesis The biosynthesis of streptogramin B is carried out by large multifunctional enzymes called non-ribosomal peptide synthetases (NRPS). In the NRPS system, each amino acid is activated as an aminoacyladenylate and is linked to the enzyme as a thioester with a phosphopantetheinyl group. An elongation reaction then occurs by transferring the activated carboxyl to the amino group in the next amino acid, thus executing the N-to-C stepwise condensation. NRPSs contain several modules on a single polypeptide. Each of these modules can catalyze activation, condensation and a modification r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Streptogramin B (aa Composition)
Streptogramin B is a subgroup of the streptogramin antibiotics family. These natural products are cyclic hexa- or hepta depsipeptides produced by various members of the genus of bacteria '' Streptomyces''. Many of the members of the streptogramins reported in the literature have the same structure and different names; for example, pristinamycin IA = vernamycin Bα = mikamycin B = osteogrycin B. Biosynthesis The biosynthesis of streptogramin B is carried out by large multifunctional enzymes called non-ribosomal peptide synthetases (NRPS). In the NRPS system, each amino acid is activated as an aminoacyladenylate and is linked to the enzyme as a thioester with a phosphopantetheinyl group. An elongation reaction then occurs by transferring the activated carboxyl to the amino group in the next amino acid, thus executing the N-to-C stepwise condensation. NRPSs contain several modules on a single polypeptide. Each of these modules can catalyze activation, condensation and a modification r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
