• Biomolecules & Therapeutics
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• v.31 no.2
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• pp.141-147
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• 2023

Antibiotic resistance has emerged as a global threat to modern healthcare systems and has nullified many commonly used antibiotics. β-Lactam antibiotics are among the most successful and occupy approximately two-thirds of the prescription antibiotic market. They inhibit the synthesis of the peptidoglycan layer in the bacterial cell wall by mimicking the D-Ala-D-Ala in the pentapeptide crosslinking neighboring glycan chains. To date, various β-lactam antibiotics have been developed to increase the spectrum of activity and evade drug resistance. This review emphasizes the three-dimensional structural characteristics of β-lactam antibiotics regarding the overall scaffold, working mechanism, chemical diversity, and hydrolysis mechanism by β-lactamases. The structural insight into various β-lactams will provide an in-depth understanding of the antibacterial efficacy and susceptibility to drug resistance in multidrug-resistant bacteria and help to develop better β-lactam antibiotics and inhibitors.

• Microbiology and Biotechnology Letters
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• v.16 no.5
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• pp.363-368
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• 1988

Molecular cloning of gene for $\alpha$-acylamino-$\beta$-lactam acylhydrolase (ALAH) III from Acetobacter turbidans has been attempted by immunochemical detection method, in which polyclonal antibody from mouse Balb/c against this enzyme was employed as a probe. As a cloning vector, λ gtll was chosen for this purpose. Two positive clones has been selected from genomic libraries of A. turbidans, which had somewhat different binding affinities on anti-ALAH III umm and anti-$\beta$-galactosidase. By restriction analysis, both clones has been turned out to lose one of EeoRI sites. From these results, it concluded that deletion of DNA between lacZ gene and inserted DNA has occurred during replication of these clones in host cells.

• Journal of Yeungnam Medical Science
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• v.27 no.1
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• pp.8-17
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• 2010

It is important to select appropriate antimicrobials for the treatment of infection according to the results of antimicrobial susceptibility tests (ASTs), yet the clinical isolates are sometimes susceptible to antibiotics that are clinically ineffective or this is due to technical error of the ASTs. So, interpretive reading of ASTs is needed and especially for the ${\beta}$-lactams for treating $Enterobacteriacae$. This review describes the interpretive reading of ASTs according to natural antimicrobial resistance and the mechanisms of mechanisms, with giving special attention to the antibiotics phenotypes for $Enterobacteriacae$. Further, as all the diffent tissues have a different antimicrobial concentration for identical antimicrobials, more information is needed on the antimicrobial tissue distribution for the appropriate treatment of infection. (ED note: I hope you send me the paper.)

• Bulletin of the Korean Chemical Society
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• v.12 no.1
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• pp.75-79
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• 1991

A series of compounds, N-(2-substituted-1-carboxy)vinylazetidinones were successfully synthesized in order to test the hypothesis that biological activities of ${\beta}$-lactam antibiotics could be attributed to the smooth flow of electrons after a nucleophilic attack at the carbonyl carbon in the ${\beta}$-lactam ring. After introduction of aminothiazolylacetamido group at 3-position of the azetidinones, their biological activities were evaluated. Their low activities led to the conclusion that the smooth electron flow in ${\beta}$-lactams in not the sufficient source for the biological activities.

• Archives of Pharmacal Research
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• v.12 no.3
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• pp.231-232
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• 1989

Although it has been known that organometallic $\beta$-lactam compounds improve the resistance to $\beta$-lactamases as well as their pharmacological activities, only a few results on organometallic $\beta$-lactam antibiotics were reported. In the course of our extensive study on the development of new cephalosporins, we were interested in organotin compounds since they show some biological activities.

• Journal of Microbiology and Biotechnology
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• v.14 no.4
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• pp.698-706
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• 2004

$\beta$-Lactam antibiotics such as penicillin G, amoxicillin, and ampicillin were determined by a potentiometric biosensor system which exploited penicillinase immobilized on Immobilon cellulose nitrate membrane and a flat-bottomed pH electrode-as the biological component and transducer. The optimum reaction buffer for maximum sensitivity was found as 2 mM of sodium phosphate buffer (pH 7.2). The detection limit of the biosensor could be extended to 1 $\mu{M}$ of the analytes by increasing the enzyme loading for immobilization to 100 units/$m\ell$. The model samples spiked with each of the standard penicillins were measured for their biosensor responses and HPLC peak area, resulting in the relative responses of 82.1-103.5% and 79.5-106.1% for the biosensor method along with HPLC analysis, respectively. This result showed a good precision of the current biosensor method for screening the penicillin compounds.

• Journal of Life Science
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• v.8 no.6
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• pp.723-728
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• 1998

Bacillus subtilis J105, high resistant bacteria against $\beta$-lactam antibiotics, become higher resistant through induction of $\beta$--lactamase in the presence of $\beta$--lactam antibiotics. When there is no antibiotics in medium, the production of resistance-inductive $\beta$--lactamase reached its plateau 15 hours later. But when there is ampicillin (500$\mu\textrm{g}$/$m\ell$) in medium, the production of enzyme reached its plateau 25 hours later since cultivating bacteria, whereas it is found that enzyme 2,900 units/$m\ell$ about 20 times as much as compared with not-presence of antibiotics was actived. In addition, as the result of MIC comparing applying ampicillin-treated and non-treated strain MIC of ampicillin-treated strain is about 2~27 times higher. It is considered that this strain induce $\beta$--lactamase production by ampicil-lin-treatment, then increasing it resistance. It is found that this resistant strain induce $\beta$--lactamase production against cephalosporin antibiotics as well as peni-cillin. As the result of examining the time of adding antibiotics for each phase of growth, it is concluded that logarith-mic phase is the most effective. As the aboves, it is suggested that this strain is a peculia strain that its resistance is induced high by various $\beta$--lactam antibiotics.

• Applied Biological Chemistry
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• v.40 no.1
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• pp.23-29
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• 1997

To develop novel cephem antibiotics, We have synthesized a new compound, named YH-487, by attaching the thiol and aminothiazole residue to $C_3$ and $C_7$ position of 7-ACA, respectively. Several characteristics such as structure, antibiotic spectrum, action mechanism, stability against ${\beta}-lactamase$ and synergistic effect were investigated. Anti-bactericidal activity of YH-487 against gram-positive and gram-negative bacteria were superior to that of the other cephem antibiotics. We have examined the action mechanisms of YH-487 using penicillin binding protein (PBP) assay, and found that the bactericidal activity was obtained by inhibiting PBP-1A, PBP-1B and PBP-3. YH-487 showed synergistic effect with gentamicin, tobramycin, and amikacin against Pseudomonas aeruginosa. In addition, YH-487 was effective against Enterobacter cloacae in combination with amikacin. Based on the above observations, YH-487 was classified as a novel third-generation ${\beta}-lactam$ antibiotics.

• Bulletin of the Korean Chemical Society
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• v.10 no.1
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• pp.33-34
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• 1989

Pig Liver Esterase (PLE) which has been known to cleave a broad range of diesters to prepare stereoselective enantiomers is applied to hydrolysis of ${\beta}-lactam$ esters imparting the corresponding acids in various yields.

• Bulletin of the Korean Chemical Society
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• v.17 no.1
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• pp.34-38
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• 1996

2-(Azetidin-2-one-1-yl)-3-phenylpropionic acid and 2-(azetidin-2-thione-1-yl)-3-phenylpropionic acid were designed as potential active site directed inactivators for carboxypeptidase A, but shown to be they are competitive reversible inhibitors for the enzyme. The observation was somewhat surprising, but is not unexpected considering the recent report of Page who questioned the validity of the generally believed notion that $\beta-lactam$ ring is highly unstable.