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61.
Lei Zhang Dr. Marina Toplak Raspudin Saleem-Batcha Lars Höing Dr. Roman Jakob Dr. Nico Jehmlich Prof. Dr. Martin von Bergen Prof. Timm Maier Prof. Robin Teufel 《Chembiochem : a European journal of chemical biology》2023,24(2):e202200632
Antimicrobial resistance represents a major threat to human health and knowledge of the underlying mechanisms is therefore vital. Here, we report the discovery and characterization of oxidoreductases that inactivate the broad-spectrum antibiotic chloramphenicol via dual oxidation of the C3-hydroxyl group. Accordingly, chloramphenicol oxidation either depends on standalone glucose-methanol-choline (GMC)-type flavoenzymes, or on additional aldehyde dehydrogenases that boost overall turnover. These enzymes also enable the inactivation of the chloramphenicol analogues thiamphenicol and azidamfenicol, but not of the C3-fluorinated florfenicol. Notably, distinct isofunctional enzymes can be found in Gram-positive (e. g., Streptomyces sp.) and Gram-negative (e. g., Sphingobium sp.) bacteria, which presumably evolved their selectivity for chloramphenicol independently based on phylogenetic analyses. Mechanistic and structural studies provide further insights into the catalytic mechanisms of these biotechnologically interesting enzymes, which, in sum, are both a curse and a blessing by contributing to the spread of antibiotic resistance as well as to the bioremediation of chloramphenicol. 相似文献
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Dr. Anne Hänchen Dr. Saskia Rausch Benjamin Landmann Dr. Luigi Toti Antje Nusser Prof. Dr. Roderich D. Süssmuth 《Chembiochem : a European journal of chemical biology》2013,14(5):625-632
The antibiotic feglymycin is a linear 13‐mer peptide synthesized by the bacterium Streptomyces sp. DSM 11171. It mainly consists of the nonproteinogenic amino acids 4‐hydroxyphenylglycine and 3,5‐dihydroxyphenylglycine. An alanine scan of feglymycin was performed by solution‐phase peptide synthesis in order to assess the significance of individual amino acid side chains for biological activity. Hence, 13 peptides were synthesized from di‐ and tripeptide building blocks, and subsequently tested for antibacterial activity against Staphylococcus aureus strains. Furthermore we tested the inhibition of peptidoglycan biosynthesis enzymes MurA and MurC, which are inhibited by feglymycin. Whereas the antibacterial activity is significantly based on the three amino acids D ‐Hpg1, L ‐Hpg5, and L ‐Phe12, the inhibitory activity against MurA and MurC depends mainly on L ‐Asp13. The difference in the position dependence for antibacterial activity and enzyme inhibition suggests multiple molecular targets in the modes of action of feglymycin. 相似文献
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A liquid chromatography–tandem mass spectrometry (LC–MS/MS) method, which has recently been developed and validated, was used for the identification and quantification of polyether ionophore, macrolide and lincosamide residues in commercial eggs sold in the metropolitan area of Rio de Janeiro, Brazil. The method was applied to 100 samples and the results showed a high incidence of polyether ionophore residues (25%). Salinomycin was detected in 21% of samples, but only two non-compliant results (5.3 and 53 µg?kg?1) were found if maximum limits (tolerances) established by European Union were adopted in Brazil and if a method decision limit (CCα) of 3.4?µg?kg?1 was considered. In 8% of analyzed samples, more than one studied coccidiostat was found. The lincosamide, lincomycin, and the macrolide, tylosin, were detected at trace levels in 4 and 1% of the samples, respectively. Lasalocid, clarithromycin and erythromycin were not found. 相似文献
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The methods of analysis for sulphonamide residues in edible animal products are reviewed. Sulphonamides are widely used for therapeutic and prophylactic purposes in both humans and animals, sometimes as growth promoters as additives in animal feed. As a result of their widespread use, there is concern about whether the levels used of these drugs can generate serious problems in human health, e.g., allergic or toxic reactions. Several methods for the determination of sulphonamides have been reported in the literature and this review considers high-performance liquid chromatography (HPLC), liquid chromatography-mass spectrometry (LC/MS), gas chromatography (GC), thin-layer chromatography (TLC), high-performance capillary electrophoresis (HPCE), enzyme-linked immunosorbant assay (ELISA), biosensor immunoassay (BIA) and microbiological methods. Specific aspects of analysing sulphonamides, such as sample handling, chromatographic conditions and detection methods are discussed. Methods for drug residue monitoring should be accurate, simple, economical in both time and cost, and capable of detecting residues below the maximum residue limits (MRL). The current sulphonamide detection technologies are based on chromatographic methods or bacteriological growth inhibition. The instrumental methods such as HPLC and GC are both sensitive and specific, but are laborious and expensive. Because of the labour-intensive processes, only a few cases of GC methods applied to residue analysis have been published. These methods are suitable for confirmation but not for screening of large numbers of samples. Microbiological methods do not require highly specialized and expensive equipment. They also use highly homogeneous cell populations for testing and thus result in better assay precision. Although HPCE has powerful separation ability, the precision is poor and the instrument still needs to be improved. To date, this technique has not been widely applied to routine analysis. Currently, TLC has been almost replaced by other instrumental analysis. A rapid, sensitive and specific assay is required to detect positive samples in routine analysis, which can then be confirmed for the presence of sulphonamides by HPLC. Immunochemical methods such as ELISA can be simple, rapid and cost-effective, with enough sensitivity and specificity to detect small molecules. This review can be considered as a basis for further research aimed at identifying the most efficient approaches. 相似文献
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Harish C. Upadhyay Dr. Gaurav R. Dwivedi Dr. Sudeep Roy Dr. Ashok Sharma Mahendra P. Darokar Dr. Santosh K. Srivastava 《ChemMedChem》2014,9(8):1860-1868
Phytol was chemically transformed into fifteen semi‐synthetic derivatives, which were evaluated for their antibacterial and drug resistance reversal potential in combination with nalidixic acid against E. coli strains CA8000 and DH5α. The pivaloyl ( 4 ), 3,4,5‐trimethoxybenzoyl ( 9 ), 2,3‐dichlorobenzoyl ( 10 ), cinnamoyl ( 11 ), and aldehyde ( 14 ) derivatives of phytol ((2E,7R,11R)‐3,7,11,15‐tetramethyl‐2‐hexadecen‐1‐ol) were evaluated by using another antibiotic, tetracycline, against the MDREC‐KG4 clinical isolate of E. coli. Derivative 4 decreased the maximal inhibitory concentration (MIC) of the antibiotics by 16‐fold, while derivatives 9 , 10 , 11 , and 14 reduced MIC values of the antibiotics up to eightfold against the E. coli strains. Derivatives 4 , 9 , 10 , 11 , and 14 inhibited the ATP‐dependent efflux pump; this was also supported by their in silico binding affinity and down‐regulation of the efflux pump gene yojI, which encodes the multidrug ATP‐binding cassette transporter protein. This study supports the possible use of phytol derivatives in the development of cost‐effective antibacterial combinations. 相似文献