Showing papers on "Thienamycin published in 2007"

Control of the production of cephamycin C and thienamycin by Streptomyces cattleya NRRL 8057

Abstract: Batch and continuous flow chemostat cultures were used to analyse the effect of environment and specific growth rate on thienamycin and cephamycin C production by Streptomyces cattleya NRRL 8057 Thienamycin was shown to be a phosphateregulated product, optimally produced in phosphate-limited cultures In batch culture, antibiotic production started as phosphate was exhausted in the medium In phosphate-limited chemostat culture, optimal production occurred at low dilution rates and low specific rate of phosphate utilisation Synthesis was severely repressed in phosphate-sufficient cultures irrespective of the specific growth rate In contrast, the growth rate, rather than the nature of the limitation, was a major controlling factor in regulating cephamycin C production Production of this antibiotic occurred, optimally at low specific growth rates, irrespective of whether phosphate, nitrogen or carbon were limiting the cultures It was therefore concluded that cephamycin C production could be regulated by phosphate, nitrogen or carbon-mediated control Ammonium nitrogen was shown to be more repressive than nitrate nitrogen Collectively the data emphasised the significance of the growth-limiting substrate and the specific growth rate on the production of these β-lactam antibiotics

Agent for suppressing formation of modified protein

Abstract: PROBLEM TO BE SOLVED: To provide an agent for suppressing the formation of a modified protein, free from hypotensive action and inducing no vitamin B6 deficiency. SOLUTION: The agent for suppressing the formation of a modified protein uses a compound having a free or salt-formed β-lactam structure as an active component. The compound having a β-lactam structure includes penicillin compounds (amoxicillin, ampicillin, oxacillin, etc.), cephem compounds (cefazolin, cefamandole, cephalexin, etc.), carbapenem compounds (thienamycin, imipenem, carpetimycin A, etc.), monocyclic β-lactam compounds (nocardin, sulfazecin, azthreonam, etc.), natural cephem compounds and other β-lactam compounds (cephalosporin C, deacetylcephalosporin C, cephamycin A, etc.). COPYRIGHT: (C)2007,JPO&INPIT

Modified protein production inhibiter

Abstract: PROBLEM TO BE SOLVED: To provide a modified protein production inhibiter which does not have a hypotensive action and does not cause vitamin B6 deficiency SOLUTION: This modified protein production inhibiter uses a compound having a free type or salt type β-lactam structure as an active ingredient The compound having the free type or salt type β-lactam structure includes penicillin-based compounds (amoxicillin, ampicillin, oxacillin, or the like), cephem-based compounds (cefazolin, cefamandole, cefalexin, or the like), carbapenem-based compounds (thienamycin, imipenem, carpetimycin A or the like), monocyclic β-lactam-based compounds (nocardin, sulfazecin, azthreonam or the like), natural cephem-based compounds and other β-lactam-based compounds (cephalosporin C, deacetylcephalosporin C, cephamycin A, or the like) COPYRIGHT: (C)2007,JPO&INPIT

Inhibition of Class A β-Lactamases

Abstract: The catalytic function of β-lactamases is the primary mechanism of bacterial resistance to β-lactam antibiotics (penicillins, cephalosporins, carbapenems). β-lactamases hydrolyze the β-lactam bond of these antibiotics, a structure modification that abrogates the antibacterial activity. β-lactams include tazobactam, a highly effective sulfone penam inhibitor, penicillanic acid sulfone sulbactam, 6-β-bromopenicillanic acid, and thienamycin. Clavulanate is a potent inhibitor of class A β-lactamases, which incidentally exhibits weak antimicrobial activity as well. A series of molecules-using sulfoxide and sulfone penams have been synthesized as starting points-with sulfhydryl and sulfide moieties at C-6; the goal of this exercise was to arrive at molecules that would simultaneously inhibit classes A and B of β-lactamases. The study also confirmed that the sulfone oxidation state of the penam thiazolidine resulted in greater inhibition. The success of BRL 42715 prompted additional efforts into compounds with a double bond at C-6, leading to the discovery of SYN-1012-with a methyl triazolyl moiety at C6 instead-and another more recent methylidene penem-with a bicyclic and heterocyclic moiety at C-6; both of these compounds show good activity against class A and C β-lactamases. Several routes have been taken towards the development of more effective inhibitors including the syntheses of variants of penam sulfones, penems, alkylidenes, monobactams, transition-state analogs, and the boronates.

Total Syntheses of Bioactive Natural Products from Carbohydrates

Abstract: Total syntheses of bioactive natural products recently accomplished in our laboratories are described. They are classified by structures of target molecules and are focused on our original approach to their own structures. The target molecules include nanaomycin, kalafungin, BE-54238B, tetracycline, rosmarinecine, thienamycin, luminacines C1 and C2, tetrodecamycin, cochleamycin A, and tubelactomicin A, which have been synthesized as optically pure form from carbohydrates.