• YAKHAK HOEJI
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• v.43 no.6
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• pp.782-788
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• 1999

7-Oxocephalosporanate 1 was treated with phosphonium salts 2~4 by Wittig reaction to afford 7-exomethylene cephalosporanates 5~7. They were oxidized to sulfones 8~10 with mCPBA. Deprotecton of benzhydryl 7-exomethylene cephalosporanate with $AlCl_3$ and NaHCO_3$ gave sodium salts of 7-exomethylene cephalosporanates 11~16. The ${\beta}-lactamase$ inhibitory activity of synthesized compounds 11~16 were compared with sulbactam, tazobactam and clavulanic acid against Type I, II, III, IV and TEM-2 $\beta$-lactamase in vitro. Compound 15 showed more potent activity than sulbactam and clavulanic acid against Type III, IV ${\beta}-lactamase$ enzyme.

• Microbiology and Biotechnology Letters
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• v.51 no.4
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• pp.474-483
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• 2023

Members of the genus Streptomyces produce more than 70% of antibiotics. The rise in antibiotic resistance globally enhanced the search for novel species with the ability to produce new bioactive compounds. This study was initiated to investigate different regions in Jordan for previously uncultured and rare Streptomyces species capable of producing novel antimicrobial compounds especially active against bacteria resistant to antibiotics. A total of 191 Streptomyces strains were isolated from 26 soil samples collected from different geographic regions in Jordan. Isolates were characterized based on colony and cellular morphology as well as using 16S rRNA gene sequencing. These isolates were screened for their ability to produce antibiotics by the perpendicular-cross streak method, and then tested by well diffusion method against tested pathogens. Fifty-four isolates showed potential to produce antimicrobial products especially active against resistant bacteria, 20.1% of the isolates showed inhibitory effect against Staphylococcus aureus, 16.9% against clinical MSSA strains, and 18.0% against MRSA: whereas only 4.2% against Esherichia coli, 3.2% against Klebsiella pneumonia, 2.7% against Pseudomonas aeruginosa, and 10.0% against clinical Candida albicans. Three isolates were selected for further identification due to their antibacterial activity against S. aureus, MRSA, and MSSA. These isolates were identified as follows; Streptomyces aburaviensis DSa3, Streptomyces alboniger SAb7 and Streptomyces misionensis ZAb2, based on cultural, biochemical characteristics and molecular analysis of the 16S rRNA.

• Food Science and Preservation
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• v.10 no.3
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• pp.394-400
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• 2003

This study was earned out to investigate the antimutagenic and cytotoxic effects of Eleutherococcus senticosus Maxim fruits ethanol extract on Salmonella typhimurium TA98, TA100 and cancer cell lines using Ames test and SRB assay, respectively. They were extracted with ethanol and then fractionated with hexane, chloroform, ethyl acetate, butanol and water to get active fractions. In the Ames test, most of the extracts had strong antimutagenic effects against the mutagenesis induced by MNNG, 4NQO, B(${\alpha}$)P and Trp-P-l. The ethanol extract (200 $\mu\textrm{g}$/plate) of Eleutherococcus senticosus fruits showed 87.2％ inhibitory effect on the mutagenesis induced by MNNG against TA100. And also, The suppression ratio against B(${\alpha}$)P and Trp-P-l in the TA100 showed 96.1％ and 95.5％, respectively. In the cytotoxic effects against human cancer cell lines (A549, AGS, MCF-7, Hep3B), the value of inhibition were mostly above 60％ for each fraction (1 mg/mL). Hexane fraction (1 mg/mL) against showed the strongest cytotoxic effects of 92.7％ compared to those of other fraction and butano fraetion against Hep3B was relatively high growth inhibitory effect of 82％.

• Journal of Plant Biotechnology
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• v.50
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• pp.97-107
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• 2023

Malaria remains to be one of the most severe global public health concerns. Traditionally, Aspilia Africana and Warburgia ugandensis have been used to treat malaria in several African countries for millennia. In the current study, A. africana calli (AaC), A. africana in vitro roots (AaIR), A. africana wild leaf (AaWL), and W. ugandensis stem bark (WuSB) were dried and pulverized. Fourier transform near-infrared spectroscopy was used to analyze the powdered samples, while 80% ethanolic extracts of each sample were assayed for antiplasmodial activity (against Plasmodium falciparum strains DD2 (chloroquine-resistant) and 3D7 (chloroquine-sensitive)) and cytotoxicity. WuSB showed the highest antiplasmodial activity (IC₅₀ = 1.57 ± 0.210 ㎍/ml and 8.92 ± 0.365 ㎍/ml against P. falciparum 3D7 and DD2, respectively) and selectivity indices (43.90 ± 7.914 and 7.543 ± 0.051 for P. falciparum 3D7 and DD2, respectively). The highest total polyphenolic contents (total phenolic and flavonoid contents of 367.9 ± 3.55 mg GAE/g and 203.9 ± 1.43 mg RUE/g, respectively) were recorded for WuSB and the lowest were recorded for AaC. The antiplasmodial activities of the tested plant tissues correlated positively with total polyphenolic content. The high selectivity indices of WuSB justify its traditional applications in treating malaria and present it as a good candidate for discovering new antimalarial compounds. We recommend elicitation treatment for AaIR, which showed moderate antiplasmodial activity against P. falciparum DD2, to increase its secondary metabolite production for optimal antimalarial activity.

• Korean Journal of Microbiology
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• v.39 no.1
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• pp.51-55
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• 2003

To develop environment-friendly biofertilizer solubilizing insoluble phosphates, a bacterium possessing a high ability to solubilize $Ca_{3}(PO_{4})_{2}$) was isolated from the rhizosphere of peas. On the basis of its morphological, cultural, physiological characteristics, and Vitek analysis, this bacterium was identified as Pantoea agglomerans. The optimal medium composition and cultural conditions for the solubilization of insoluble phosphate by P. agglomerans R-38 were 3% of glucose.0.1% of TEX>$NH_{4}NO_{3}$, 0.02% of $MgSO_{4}\cdot\7H_{2}O$, and 0.06% of $CaCl_{2}\cdot\2H_{2}O$ along with initial pH 7.5 at $30^{\circ}C$. The highest soluble phosphate production under optimum condition was 898 mg/L after 5 days of cultivation. The solubilization of insoluble phosphate was associated with a drop in the pH of the culture medium. The strain produced soluble phosphate to the culture broth with the concentrations of 698 mg/L against CaHPO$_4$, 912 mg/L against hydroxyapatite, 28 mg/L against $FePO_{4}\cdot\4H_{2}O$, and 19 mg/L against $AIPO_{4}$, respectively.

• YAKHAK HOEJI
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• v.41 no.2
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• pp.225-232
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• 1997

The in vitro antibacterial activity of DWP20367 (1-Cyclopropyl-6-fluoro-8-chloro-7-(2,7-diazabicyclo[3,3,0]oct-4-ene-7-yl)-1,4-dihydro-4-oxoquinoline-3-carboxylic acid), a new broad-spectrum fluoroquinolone, was compared with those of ciprofloxacin (CPFX), sparfloxacin (SPFX) and ofloxacin (OFLX). DWP20367 was showed antibacterial activity much higher than CPFX, SPFX and OFLK against gram-positive bacteria, while it was slightly more superior to quinolones against gram-negative bacteria. DWP20367 was particularly effective against MRSA, and its $MlC_{90}$ against clinical isolates of methicillin-susceptible S. aureus, low methicillin-resistant S. aureus and high methicillin-resistant S. aureus were 0.098, 0.781 and 1.563 micro g/ml, respectively. Against S. pneumoniae, MIC90 of DWP20367 was 2- to 8-fold higher than those of CPFX. With a view of MIC90, DWP20367 showed slightly more potent activity against P. aeruginosa and E. coli isolates than the control quinolones. DWP20367 activity was not affected by inoculum size and medium pH. But addition of $Mg^{2+}, \;Ca^{2+} $Mg2+, Ca2+ or horse serum (25%) decreased its antibacterial activity. DWP20367 was showed rapidly bactericidal activity within 2 to 4 h, and regrowth was not observed even after 24 h incubation at concentrations near the 4-fold of MIC.

• BMB Reports
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• v.42 no.7
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• pp.418-420
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• 2009

We describe a method for producing polyclonal antibodies against peptide antigen cytochrome P450 1A2 and 3A4 using a tandem repeat of the epitope region and incorporation of proline residue between the repeated sequences. An ELISA assay revealed more efficient generation of polyclonal antibodies to tandem repeat peptide antigens than mono-epitope peptides. The incorporation of proline residues further stimulated antibody production.

• YAKHAK HOEJI
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• v.32 no.4
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• pp.222-229
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• 1988

A series of substituted benzylthioalkanamidocephalosporins 3a-3p were synthesized and tested in vitro antibacterial activity. Of these new cephalosporins exhibited good antibacterial activity against Gram-positive bacteria whereas none of the compounds possessed the activity against Gram-negative bacteria at the concentration tested.

• Fisheries and Aquatic Sciences
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• v.5 no.3
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• pp.150-155
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• 2002

Marine bacteria producing algicidal substance against Cochlodinium polykrikoides was screened and isolated from seawater. Metabolite of marine bacteria Micrococcus sp. LG-5 showed strong algicidal activity against C. polykrikoides. C. polykrikoides was inhibited above $90\%$ at $5\%$ solution of the metabolite within 24 hrs. Algicidal substance from the metabolite was extracted with ethyl acetate, and then purified by PTLC and reversed-phase HPLC. Algicidal activity of purified compound against C. polykrikoides was above $90\%$ at 3.7, 11.0 and 33.0${\mu}g/mL$ concentration after 12, 9 and 3 hrs, respectively. Ninety percent inhibition of other red tides, Gymnodinium sanguineum and Gyrodinium impudicum was observed when treated with 3.7${\mu}g/mL$ of purified compound within a period of 12 hrs. The microscopic view of red tides treated with purified compound showed the deformations such as cell node cuts and swelling of cells.

• Korean Journal of Microbiology
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• v.42 no.3
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• pp.223-229
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• 2006

To develop multifunctional microbial inoculant, an insluble phosphate-solubilizing bacterium with antifungal activity was isolated from plant rhizospheric soil. On the basis of its morphological, cultural and physiological characteristics and Biolog analysis, this bacterium was identified as Pseudomonas fluorescens RAF15. P. fluorescens RAF15 showed antifungal activities against phytopathogenic fungi Botrytis cinerea and Rhizoctonia solani. The optimal medium composition and cultural conditions for the solubilization of insoluble phosphate by P. fluorescens RAF15 were 1.5% of glucose, 0.005% of urea, 0.3% $MgCl_2{\cdot}6H_2\;0.01%\;of\;MgSO_4{\cdot}7H_2O\;0.01%,\;of\;CaCl_2{\cdot}2H_2O$, and 0.05% of NaCl along with initial pH 7.0 at $30^{\circ}C$. The soluble phosphate production under optimum condition was 863 mg/L after 5 days of cultivation. The solubilization of insoluble phosphates was associated with a drop in the pH of the culture medium. P. fluorescens RAF15 showed resistance against different environmental stresses like $10-35^{\circ}C$ temperature, 1-4% salt concentration and pH 2-11 range. The strain produced soluble phosphate to the culture broth with the concentrations of 971-1121 mg/L against $CaHPO_4$, 791-908 mg/L against $Ca_3(PO_4){_2}$, and 844 mg/L against hydroxyapatite, respectively. However, the strain produced soluble phosphate to the culture broth with the concentrations of 15 mg/L against $FePO_4$, and 5 mg/L against $AlPO_4$, respectively.