• Archives of Pharmacal Research
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• 제15권2호
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• pp.187-189
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• 1992

In the preceding paper, we reported the synthessis and biological properties of cephalosporins having quinoliniumthiomethyls at the C-3 position and demonstrated that quinoliniumthiomethylcephalosporins exhibited an extended antibacterial spectrum including antipseudomonal activity, especially strong antiGram-positive activity. With the aim of elaboration to optimize the antibacterial potency of the quaternary ammonium cephalosporins, we have studied the modification of substituents in the pyrrolidine ring of cefepime 1 which is characterized by its potent activity.

• IMMUNE NETWORK
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• 제20권6호
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• pp.47.1-47.13
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• 2020

Tetracyclines, which have long been used as broad-spectrum antibiotics, also exhibit a variety of nonantibiotic activities including anti-inflammatory and immunomodulatory properties. Tetracyclines bind to the 30S ribosome of the bacteria and inhibit protein synthesis. Unlike antimicrobial activity, the primary molecular target for the nonantibiotic activity of tetracycline remains to be clarified. Nonetheless, the therapeutic efficacies of tetracyclines, particularly minocycline and doxycycline, have been demonstrated in various animal models of autoimmune disorders, such as multiple sclerosis, rheumatoid arthritis, and asthma. In this study, we summarized the anti-inflammatory and immunomodulatory activities of tetracyclines, focusing on the mechanisms underlying these activities. In addition, we highlighted the on-going or completed clinical trials with reported outcomes.

• 한국미생물·생명공학회지
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• 제7권3호
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• pp.127-133
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• 1979

5'-GMP의 직접발효생산균주의 분리목적으로 Breuibacterium ammoniagenes ATCC 6871에 자외선조사 및 NTG, DES 등의 변이제처리를 한 결과 guanine계 핵산관련물질을 직접 배지중에 축적하는 변이주는 분리할 수 없었으며, adenine영양요구주로써 GMP-reductase가 결핍되고 adenosine 및 AMP에 의해 생육저해를 받지 않는 변이주가 XMP-aminase activity가 현저히 높았음을 알았다. 이러한 변이주중 BA-17-2가 XMP-aminase의 activity가 가장 높았으며 또한 전환된 5'-GMP를 GDP나 GTP로 거의 인산화하지 않았으며 그리고 guanosine이나 guanine으로 분해하지 않았다. 생성된 5'-GMP를 anion exchange resin Duolite 102 D를 사용하여 분리하고 ultraviolet 및 Infra-red spectrum을 조사한 결과 5'-GMP로 동정되었다.

• Clinical and Experimental Pediatrics
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• 제51권10호
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• pp.1031-1037
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• 2008

Macrolide antimicrobial agents including erythromycin, roxithromycin, clarithromycin, and azithromycin are commonly used in the treatment of respiratory tract infections in children. Newer macrolides that have structural modifications of older drug erythromycin show improved change in the spectrum of activity, dosing, and administration. However, recent studies reported that increasing use of macrolide antibiotics is the main force driving the development of macrolide resistance in streptococci. In particular, azithromycin use is more likely to select for macrolide resistance with Streptococcus pneumoniae than is clarithromycin use, a possible reflection of its much longer half life. Recently, erythromycin resistance rates of S. pneumoniae and Streptococcus pyogenes are rapidly increasing in Korea. Two main mechanisms of acquired macrolide resistance have been described, altered binding site on the bacterial ribosome encoded by the ermB gene and active macrolide efflux pump encoded by the mef gene. Relationship between the susceptibility of S. pneumoniae and the response to macrolides has been shown in studies of acute otitis media, but less clear in cases of pneumonia. This article reviews the spectrum of activity, pharmacokinetic properties, mechanisms of action and resistance, and clinical implication of resistance on the treatment of respiratory tract infections in children.

• Journal of Microbiology and Biotechnology
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• 제13권5호
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• pp.773-777
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• 2003

The color of Congo red hinders the spectrometric measurements of a concentration of hydrogen peroxide and enzyme activity (Horseradish peroxidase; HRP) during enzymatic decoloring of Congo red. In this study, a method was developed to measure peroxidase activity and hydrogen peroxide concentration in the presence of Congo red. The oxidation product of HRP/hydrogen peroxide and ABTS(2,2'-azino-bis-(3-ethylbenzotriazoline-6-sulfonic acid)) formed a dark green color. The spectrum of this product showed absorption bands at 420 nm and 734 nm. When compared with the Congo red spectrum, the absorption at 734 nm of this product did not overlap with Congo red, thus making the hydrogen peroxide measurement possible even in the presence of Congo red. Kinetic study of decoloring of Congo red performed by this method showed that the decoloring reaction followed the Michaelis-Menten kinetics. Pulse feeding of hydrogen peroxide, upon depletion, significantly increased the decoloring of Congo red. This result shows that this newly developed technique can monitor, predict, and improve the enzymatic decoloring process.

• Journal of Microbiology and Biotechnology
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• 제20권10호
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• pp.1397-1402
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• 2010

Papyriflavonol A (PapA), a prenylated flavonoid [5,7,3',4'-tetrahydroxy-6,5'-di-(${\gamma},{\gamma}$-dimethylallyl)-flavonol], was isolated from the root barks of Broussonetia papyrifera. Our previous study showed that PapA has a broad-spectrum antimicrobial activity against pathogenic bacteria and fungi. In this study, the mode of action of PapA against Candida albicans was investigated to evaluate PapA as an antifungal agent. The minimal inhibitory concentration (MIC) values were 10~25 ${\mu}g/ml$ for C. albicans and Saccharomyces cerevisiae, Gram-negative bacteria (Escherichia coli and Salmonella typhimurium), and Gram-positive bacteria (Staphylococcus epidermidis and Staphylococcus aureus). The kinetics of cell growth inhibition, scanning electron microscopy, and measurement of plasma membrane florescence anisotrophy revealed that the antifungal activity of PapA against C. albicans and S. cerevisiae is mediated by its ability to disrupt the cell membrane integrity. Compared with amphotericin B, a cell-membrane-disrupting polyene antibiotic, the hemolytic toxicity of PapA was negligible. At 10~25 ${\mu}g/ml$ of MIC levels for the tested strains, the hemolysis ratio of human erythrocytes was less than 5%. Our results suggest that PapA could be a therapeutic fungicidal agent having potential as a broad spectrum antimicrobial agent.

• Biomolecules & Therapeutics
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• 제7권3호
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• pp.242-248
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• 1999

Diazepam, a benzodiazepine (BDZ) agonist, produces sedation and flumazenil, a BDZ antagonist, blocks these actions. The aim of this study was to examine the effects of BDZs on cortical electroencephalogram (EEG) in rats. The recording electrodes were implanted over the frontal and parietal cortices bilaterally, and the reference and ground electrodes over cerebellum under ketamine anesthesia. To assess the effects of diazepam and flumazenil, rats were injected with diazepam (1 mgHg, i.p.) and/or flumazenil ( 1 mg/kg, i.p.), and the EEG was recorded before and after drugs. Normal awake had theta peak in the spectrum and low amplitude waves, while normal sleep showed large amplitude of slow waves. The powers of delta, theta and alpha bands were increased during sleep compared with during awake. Diazepam reduced the mobility of the rat and induced sleep with intermittent fast spindles and large amplitude of slow activity, and it produced broad peak over betaL band and increased the power of gamma band, which were different from EEG patterns in normal sleep. Saline injection awakened rats and abolished fast spindles for a short period about 2-5 min from EEG pattern during diazepam-induced sleep. Flumazenil blocked both diazepam-induced sleep and decreased the slow activities of delta, theta, alpha and betaL, but not of gamma activity for about 10 min or more. This study may indicate that decrease in power of betaL and betaH bands can be used as the measure of central action of benzodiazepines, and that the EEG parameters of benzodiazepines have to be measured without control over the behavioral state by experimenter.

• Fisheries and Aquatic Sciences
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• 제26권6호
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• pp.393-405
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• 2023

The aim of this research was to enhance the flavor of visceral extracts from skipjack tuna. Flavor precursors and the optimum condition for the Maillard reaction were determined. The flavor extract was prepared from the tuna viscera using Endo/Exo Protease controlled in 3 factors; temperature, enzyme amounts and incubation time. The optimal condition for producing tuna viscera protein hydrolysate (TVPH) was 60℃, 0.5% enzyme (w/w) and 4-hour incubation time. TVPH were further processed to tuna viscera flavor enhancer (TVFE) with Maillard reaction. The Maillard reactions of TVFE were conducted with or without supplements such as xylose, yeast extract and methionine. The Maillard volatile components were analyzed with gas chromatography-mass spectrometry. Sixteen volatiles such as 2-methylpropanal, methylpyrazine, 2,5-dimethylpyrazine, dimethyl disulfide and 2-acetylthaizone were newly formed via Maillard reaction and the similarity of volatile contents from TVPH and TVFE were virtualized using Pearson's correlation integrated with heat-map and principal component analysis. To virtualize aromagram of TVPH and TVFE, odor activity value and odor impact spectrum (OIS) techniques were applied. According to OIS results, 3-methylbutanal, 2-methylbutanal, 1-octen-3-ol 2,5-dimethylpyrazine, methional and dimethyl trisulfide were the potent odorants contributed to the meaty, creamy, and toasted aroma in TVFE.

• Journal of Microbiology and Biotechnology
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• 제34권6호
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• pp.1189-1196
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• 2024

Bacterial resistance to commonly used antibiotics is one of the major challenges to be solved today. Bacteriophage endolysins (Lysins) have become a hot research topic as a new class of antibacterial agents. They have promising applications in bacterial infection prevention and control in multiple fields, such as livestock and poultry farming, food safety, clinical medicine and pathogen detection. However, many phage endolysins display low bactericidal activities, short half-life and narrow lytic spectrums. Therefore, some methods have been used to improve the enzyme properties (bactericidal activity, lysis spectrum, stability and targeting the substrate, etc) of bacteriophage endolysins, including deletion or addition of domains, DNA mutagenesis, chimerization of domains, fusion to the membrane-penetrating peptides, fusion with domains targeting outer membrane transport systems, encapsulation, the usage of outer membrane permeabilizers. In this review, research progress on the strategies for improving their enzyme properties are systematically presented, with a view to provide references for the development of lysins with excellent performances.

• Journal of Microbiology and Biotechnology
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• 제28권9호
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• pp.1563-1572
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• 2018

Gold nanoparticles (AuNP) and their conjugates have been gaining a great deal of recognition in the medical field. Meanwhile, extended-spectrum ${\beta}$-lactamases (ESBL)-producing bacteria are also demonstrating a challenging problem for health care. The aim of this study was the biosynthesis of AuNP using Rosa damascenes petal extract and conjugation of ceftriaxone antibiotic (Cef-AuNP) in inhibiting ESBL-producing bacteria and study of in vitro anticancer activity. Characterization of the synthesized AuNP and Cef-AuNP was studied. ESBL-producing strains, Acinetobacter baumannii ACI1 and Pseudomonas aeruginosa PSE4 were used for testing the efficacy of Cef-AuNP. The cells of MCF-7 breast cancer were treated with previous AuNP and Cef-AuNP at different time intervals. Cytotoxicity effects of apoptosis and its molecular mechanism were evaluated. Ultraviolet-visible spectroscopy and Fourier transform infrared spectroscopy established the formation of AuNP and Cef-AuNP. Transmission electron microscope demonstrated that the formed nanoparticles were of different shapes with sizes of 15~35 nm and conjugation was established by a slight increase in size. Minimum inhibitory concentration (MIC) values of Cef-AuNP against tested strains were obtained as 3.6 and $4{\mu}g/ml$, respectively. Cef-AuNP demonstrated a decrease in the MIC of ceftriaxone down to more than 27 folds on the studied strains. The biosynthesized AuNP displayed apoptotic and time-dependent cytotoxic effects in the cells of MCF-7 at a concentration of $0.1{\mu}g/ml$ medium. The Cef-AuNP have low significant effects on MCF-7 cells. These results enhance the conjugating utility in old unresponsive ceftriaxone with AuNP to restore its efficiency against otherwise resistant bacterial pathogens. Additionally, AuNP may be used as an alternative chemotherapeutic treatment of MCF-7 cancer cells.