• Applied Chemistry for Engineering
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• v.22 no.2
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• pp.119-124
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• 2011

Currently, people are exposed to many harmful diseases. Therefore, there are many schemes, such as automation of productive facilities, development of information and communication technology, enhanced the quality of human life and wealth. However, these processes lead to weakened immune system. Thus, people are more vulnerable to infections from pathogens and environmental stress. Misuse and abuse of drugs resulted in the rapid emergence of multidrug-resistant microbes and tumors, therefore, to find new antibiotics are urgently needed. One of them is a peptide-antibiotic, that is not or less occurred a drug-resistance, comparing to conventional drugs. Peptides with various antibiotic activities have been identified from life organisms. The present review provides an overview of activities and application of peptide antibiotics.

• Journal of Pharmacopuncture
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• v.25 no.1
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• pp.37-45
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• 2022

Objectives: The quorum-sensing-inhibitory and anti-biofilm activities of the methanol extract of E. globulus leaves were determined against clinically isolated multidrug-resistant Pseudomonas aeruginosa. Methods: The preliminary anti-quorum-sensing (AQS) activity of eucalyptus was investigated against a biosensor strain Chromobacterium violaceum ATCC 12472 (CV12472) by using the agar well diffusion method. The effect of sub-minimum inhibitory concentrations (sub-MICs) of the methanol extract of eucalyptus on different quorum-sensing-regulated virulence factors, such as swarming motility, pyocyanin pigment, exopolysaccharide (EPS), and biofilm formation, against clinical isolates (CIs 2, 3, and 4) and reference PA01 of Pseudomonas aeruginosa were determined using the swarm diameter (mm)-measurement method, chloroform extraction method, phenol (5%)-sulphuric acid (concentrated) method, and the microtiter plate assay respectively, and the inhibition (%) in formation were calculated. Results: The preliminary AQS activity (violacein pigment inhibition) of eucalyptus was confirmed against Chromobacterium violaceum ATCC 12472 (CV12472). The eucalyptus extract also showed concentration-dependent inhibition (%) of swarming motility, pyocyanin pigment, EPS, and biofilm formation in different CIs and PA01 of P. aeruginosa. Conclusion: Our results revealed the effectiveness of the E. globulus extract for the regulation of quorum-sensing-dependent virulence factors and biofilm formation at a reduced dose (sub-MICs) and suggest that E. globulus may be a therapeutic agent for curing and controlling bacterial infection and thereby reducing the possibility of resistance development in pathogenic strains.

• Journal of Microbiology and Biotechnology
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• v.30 no.2
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• pp.226-236
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• 2020

Antibiotic resistance by pathogenic bacteria and fungi is one of the most serious global public health problems in the 21^st century, directly affecting human health and lifestyle. Pseudomonas aeruginosa and Staphylococcus aureus with strong resistance to the common antibiotics have been isolated from Intensive Care Unit patients at Zagazig Hospital. Thus, in this study we assessed the biocidal activity of nanoparticles of silver, copper and zinc synthesized by Fusarium solani KJ 623702 against these multidrug resistant-bacteria. The synthesized Metal Nano-particles (MNPs) were characterized by UV-Vis spectroscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and Zeta potential. The Fourier transform infrared spectroscopy (FTIR) result showed the presence of different functional groups such as carboxyl, amino and thiol, ester and peptide bonds in addition to glycosidic bonds that might stabilize the dispersity of MNPs from aggregation. The antimicrobial potential of MNPs by F. solani against the multidrug-resistant (MDR) P. aeruginosa and S. aureus in addition to the mycotoxigenic Aspergillus awamori, A. fumigatus and F. oxysporum was investigated, based on the visual growth by diameter of inhibition zone. Among the synthesized MNPs, the spherical AgNPs (13.70 nm) displayed significant effect against P. aeruginosa (Zone of Inhibition 22.4 mm and Minimum Inhibitory Concentration 21.33 ㎍/ml), while ZINC oxide Nano-Particles were the most effective against F. oxysporum (ZOI, 18.5 mm and MIC 24.7 ㎍/ml). Transmission Electron Microscope micrographs of AgNP-treated P. aeruginosa showed cracks and pits in the cell wall, with internalization of NPs. Production of pyocyanin pigment was significantly inhibited by AgNPs in a concentration-dependent manner, and at 5-20 ㎍ of AgNPs/ml, the pigment production was reduced by about 15-100%, respectively.

• Journal of Microbiology and Biotechnology
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• v.29 no.9
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• pp.1460-1469
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• 2019

The extensive distribution of multidrug-resistant (MDR) methicillin-resistant Staphylococcus aureus (MRSA) poses a threat to healthcare worldwide. This study aimed to investigate the MDR and molecular patterns of MRSA isolates in children admitted to the two biggest tertiary care pediatric hospitals in northern and southern Vietnam. A total of 168 MRSA strains were collected to determine antibiotic susceptibility by minimum inhibitory concentration tests. Antibiotic-resistant genes, pulsed-field gel electrophoresis, staphylococcal cassette chromosome mec (SCCmec) typing, and multilocus sequence typing were used for the molecular characterization of MRSA. Among the total strains, the MDR rate (51.8%) was significantly higher in the northern hospital than in the southern hospital (73% vs. 39%, p < 0.0001). The MDR-MRSA with the highest rates were "ciprofloxacin-erythromycin-gentamicintetracyclines" (35.6%), followed by "erythromycin-tetracycline-chloramphenicol" (24.1%), and "ciprofloxacin-erythromycin-gentamicin" (19.5%), showing an accumulative total of 79.3%. The most susceptible antibiotics were rifampicin (100%) and vancomycin (100%), followed by doxycycline (94.0%), meropenem (78.0%), and cefotaxime (75.0%). The SCCmecII strains showed greater resistance to gentamicin, ciprofloxacin, tetracycline, meropenem and cephalosporins compared with the other strains. The SCCmecII strains exhibited the highest rate in the tested genes (aacA/aphD: 55.2%, ermA/B/C: 89.7%, and tetK/M: 82.8%). ST5-SCCmecII was the predominant clone in the northern hospital, whereas SCCmecIVa was more pronounced in the southern hospital. In conclusion, our results raised concerns about the predominant MDR-MRSA strains in the pediatric hospitals in Vietnam. The north-south difference in the antibiotic resistance patterns and genetic structure of MRSA suggests different MRSA origins and various uses of antimicrobial agents between the two regions.

• Tuberculosis and Respiratory Diseases
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• v.59 no.6
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• pp.600-605
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• 2005

Background : Primary multidrug-resistant tuberculosis is defined as Mycobacterium tuberculosis isolates that are resistant to at least isoniazid and rifampin in never-been-treated tuberculosis patients, and this malady is caused by the transmission of a resistant strain from one patient, who is infected with a resistant Mycobacterium tuberculosis strain, to another patient. The prevalence of primary multidrug-resistant tuberculosis could be a good indicator of the performance of tuberculosis control programs in recent years. We conducted a case-control study to identify the risk factors for primary multidrug-resistant tuberculosis. Methods : From January 1, 2001 to, June 30, 2003, by conducting prospective laboratory-based surveillance, we identified 29 hospitalized patients with P-MDRTB and these patients constituted a case group in this study. The controls were represented by all the patients with culture-confirmed drug susceptible tuberculosis who were admitted to National Masan Hospital during the same study period. The odds ratios for the patients with primary multidrug-resistant tuberculosis, as compared with those of the patients with drug susceptible tuberculosis, were calculated for each categorical variable with 95% confidence intervals. Results : Multivariate logistic regression showed that the presence of diabetes mellitus (odds ratio 2.68; 95% confidence interval, 1.05-6.86) was independently associated with having primary multidrug-resistant tuberculosis. Conclusion : This study has shown that diabetes mellitus might be one of the risk factors for primary multidrug-resistant tuberculosis.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.5
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• pp.613-618
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• 2005

This study was carried out to examine the effects of gamma irradiation on the cytotoxicity and multidrug-resistance reversing activity of methanol extracts from Coix lachryma-jobi L. var. me-yuen Stapf seed. The seed was irradiated with doses of 1, 4, 8, 16, 32 and 64 Gy of the gamma radiation, and then extracted by methanol. The extracts were examined for cytotoxicity on the human cancer cell lines, MCF-7 (human breast adenocarcinoma pleural effusion), Calu-6 (human pulmonary carcinoma) and SNU-601 (human gastric carcinoma) cells, and investigated for multidrug-resistance reversing activity using drug sensitive AML-2/WT and multidrug-resistant AML-2/D100 cells. The growth inhibitory activity of irradiated seed extracts on human cancer cell lines was higher than that of the control. In the case of Calu-6 cell line, the effect of cytotoxicity was observed in the extracts of 4, 8 and 16 Gy. $IC_{50}$ value in the MCF-7 cell line was measured in the only 8 Gy extract. And in the SNU-601 cell line as Calu-6, the effect of cytotoxicity was observed in the extracts of 4, 8 and 16 Gy. But the extracts of gamma-irradiated seed over 32 Gy showed little growth inhibitory effect against human cancer cell lines. In this result, 8 Gy extract had significant growth inhibitory in all human cancer cell lines $(Calu-6:\;633\;{\mu}g/mL,\;MCF-7:\;653\;{\mu}g/mL\;and\;SNU-601:\;683\;{\mu}g/mL)$. The extracts of 4, 8 and 16 Gy strongly potentiated vincristine cytotoxicity in AML-2/D100 cells. The reversal fold (RF) of 4, 8 and 16 Gy extracts was 1.7, 1.8 and 1.6, respectively. But their cytotoxicities to both sensitive AML-2/WT and resistant AML-2/D100 cells were in the same order of magnitude. These results indicate that the above samples would contain some principles which have cytotoxicity and multidrug-resistance reversing activity. Irradiation technology can be applied to promote physiological activities of medicinal plant seeds.

• Journal of Microbiology and Biotechnology
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• v.30 no.8
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• pp.1180-1183
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• 2020

The prevalence and characterization of plasmid-mediated quinolone resistance (PMQR) determinants in ciprofloxacin-resistant Escherichia coli isolated from a Korean commercial layer farm were studied. A total of 45 ciprofloxacin-resistant E. coli isolates were recovered and all isolates were multidrug-resistant. Eight isolates have the PMQR genes aac(6')-Ib-cr, qnrS1, and qnrB4, and seven isolates exhibited double amino acid exchange at both gyrA and parC, and have high fluoroquinolone minimum inhibitory concentrations. Five transconjugants demonstrated transferability of PMQR and β-lactamase genes and similar antimicrobial resistance. Because PMQR genes in isolates from commercial layer chickens could enter the food supply and directly affect humans, control of ciprofloxacin resistance is needed.

• Archives of Pharmacal Research
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• v.29 no.9
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• pp.757-761
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• 2006

Six protoberberine alkaloids were isolated from the chloroform layer of the rhizome of Coptis japonica Makino (Ranunculaceae). The structures of the isolated compounds were determined to be 6-([1,3]dioxolo[4,5-g]isoquinoline-5-carbonyl)-2,3-dimethoxy-benzoic acid methyl ester (1), oxyberberine (2), 8-oxo-epiberberine (3), 8-oxocoptisine (4), berberine (5) and palmatine (6) by physicochemical and spectroscopic methods. The compound 3 (8-oxo-epiberberine) was first isolated from natural sources. The compounds were tested for cytotoxicity against five tumor cell lines in vitro by SRB method, and also tested for the MDR reversal activities. Compound 4 was of significant P-gp MDR inhibition activity with ED50 value $0.018\;{\mu}g/mL$ in MES-SA/DX5 cell and $0.0005\;{\mu}g/mL$ in HCT15 cell, respectively.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.9
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• pp.5089-5093
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• 2013

Objective: This study aimed to investigate the effects of BCRP expression on tumor recurrence, metastasis and treatment tolerability. Methods: A VX2 rabbit liver tumor model was established. Division was randomly into 4 groups: namely saline control group; A group, given hydration lipiodol; B group, Ad-p53; and C group, Ad-p53+hydration lipiodol. After the intervention, samples were collected to detect the BCRP, MMP-2, VEGF and PCNA. Results: The expression of BCRP, MMP-2, PCNA and VEGF in tumors in Group A had no significant difference when compared with the control group, while in B and C group, the values were significantly lower (P<0.05). BCRP positive expression in metastatic lesions significantly increased (P<0.05), and was correlated with MMP-2 ($X^2=6.172$, P=0.0131). Conclusions: BCRP may play an important role in mediating liver cancer multidrug resistance to chemotherapy, and may be correlated with tumor recurrence and metastasis, which leads to weakened treatment effect. Ad-P53 can down-regulate the expression of related genes, playing a role in multidrug resistance reversal and increased sensitivity in liver cancer treatment.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.8
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• pp.4853-4858
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• 2013

Objectives: To investigate whether hypoxia has an effect on regulation of multidrug resistance (MDR) to chemotherapeutic drugs in laryngeal carcinoma cells and explore the role of hypoxia-inducible factor-$1{\alpha}$ (HIF-$1{\alpha}$). Methods: Laryngeal cancer cells were cultured under normoxic and hypoxic conditions. The sensitivity of the cells to multiple drugs and levels of apoptosis induced by paclitaxel were determined by MTT assay and annexin-V/propidium iodide staining analysis, respectively. HIF-$1{\alpha}$ expression was blocked by RNA interference. The expression of HIF-$1{\alpha}$ gene was detected by real-time quantitative RT-PCR and Western blotting. The value of fluorescence intensity of intracellular adriamycin accumulation and retention in cells was evaluated by flow cytometry. Results: The sensitivity to multiple chemotherapy agents and induction of apoptosis by paclitaxel could be reduced by hypoxia (P<0.05). A the same time, the adriamycin releasing index of cells was increased (P<0.05). However, resistance acquisition subject to hypoxia in vitro was suppressed by down-regulating HIF-$1{\alpha}$ expression. Conclusion: HIF-$1{\alpha}$ could be considered as a key regulator for mediating hypoxia-induced MDR in laryngeal cancer cells via inhibition of drug-induced apoptosis and decrease in intracellular drug accumulation.