Effects of several beta-lactam antibiotics on the acetaldehyde-metabolizing system were studied using germ-free rats. Administration of cefamandole (CMD) to the rats caused a decrease in liver mitochondrial low Km aldehyde dehydrogenase activity and an increase in blood acetaldehyde level during ethanol metabolism, similar to the case in conventional rats. Oral administration of CMD produced a ...

Two types of mutants highly sensitive to beta-lactam antibiotics were obtained from Pseudomonas aeruginosa PAO 2142 by treatment with N-methyl-N'-nitro-N-nitrosoguanidine. One type of mutant showed over 30 times higher sensitivity to mecillinam, carbenicillin and sulbenicillin than did the parent, but not to most other beta-lactam antibiotics tested. In contrast, the other type mutant was about...

Due to the emerging resistance against classical β-lactam-based antibiotics, a growing number of bacterial infections has become harder to treat. This alarming tendency necessitates continued research on novel antibacterial agents. Many classes of β-lactam antibiotics are characterized by the presence of the 3-aminoazetidin-2-one core, which resembles the natural substrate of the target penicil...

Beta-lactamases are a superfamily of enzymes which degrade the β-lactam class of antibiotics. They are produced endogenously by the bacterial cells, which when exposed to the β-lactam class of antibiotics inactivate them by cleaving the β-lactam ring. Based on the presence or absence of metallic ligand, β-lactamases have been divided into two broad functional classes. β-Lactamases are a constit...

OBJECTIVE To compare beta lactam monotherapy with beta lactam-aminoglycoside combination therapy for severe infections. DATA SOURCES Medline, Embase, Lilacs, Cochrane Library, and conference proceedings, to 2003; references of included studies; contact with all authors. No restrictions, such as language, year of publication, or publication status. STUDY SELECTION All randomised trials of be...

Two series of tricyclic inhibitors of the serine protease thrombin, imides (+/-)-1-(+/-)-8 and lactams (+/-)-9-(+/-)-13, were analysed to evaluate contributions of orthogonal multipolar interactions with the backbone C=O moiety of Asn98 to the free enthalpy of protein-ligand complexation. The lactam derivatives are much more potent and more selective inhibitors (K(i) values between 0.065 and 0....

BACKGROUND The first line of defense by bacteria against β-lactam antibiotics is the expression of β-lactamases, which cleave the amide bond of the β-lactam ring. In the reaction of biapenem inactivation by B2 metallo β-lactamases (MβLs), after the β-lactam ring is opened, the carboxyl group generated by the hydrolytic process and the hydroxyethyl group (common to all carbapenems) rotate around...

The emergence of clinically relevant ?-lactam-resistant bacteria poses a serious threat to human health and presents major challenge for medical treatment. How opportunistic pathogenic acquire antibiotic resistance the prevalence antibiotic-resistant in environment are still unclear. In this study, we further confirmed that selective pressure heavy metals contributes increase ampicillin-resista...

BACKGROUND & OBJECTIVES Multidrug-resistance of methicillin-resistant Staphylococcus aureus (MRSA) is a serious therapeutical problem. Chalcones belong to a group of naturally occurring flavonoids, usually found in various plant species, and have potent antibacterial, antiviral and antifungal activities. The goal of this study was to evaluate the antibacterial effect of three newly-synthesized ...

Nonribosomal peptide synthetases are versatile engines of bioactive natural product biosynthesis that function according to the multiple carrier thiotemplate mechanism. C-terminal thioesterase (TE) domains of these giant modular proteins typically catalyze product release by hydrolysis or macrocyclization. We now report an unprecedented, dual-function TE that is involved in the biosynthesis of ...