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Dasagrandhi, Chakradhar,Park, Seulki,Jung, Won-Kyo,Kim, Young-Mog MDPI 2018 INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES Vol.19 No.8
<P>The emergence of more virulent forms of human pathogenic bacteria with multi-drug resistance is a serious global issue and requires alternative control strategies. The current study focused on investigating the antibacterial and antibiofilm potential of ferulic acid-grafted chitosan (CFA) against <I>Listeria monocytogenes</I> (LM), <I>Pseudomonas aeruginosa</I> (PA), and <I>Staphylococcus aureus</I> (SA). The result showed that CFA at 64 µg/mL concentration exhibits bactericidal action against LM and SA (>4 log reduction) and bacteriostatic action against PA (<2 log colony forming units/mL reduction) within 24 h of incubation. Further studies based on propidium iodide uptake assay, measurement of material released from the cell, and electron microscopic analysis revealed that the bactericidal action of CFA was due to altered membrane integrity and permeability. CFA dose dependently inhibited biofilm formation (52–89% range), metabolic activity (30.8–75.1% range) and eradicated mature biofilms, and reduced viability (71–82% range) of the test bacteria. Also, the swarming motility of LM was differentially affected at sub-minimum inhibitory concentration (MIC) concentrations of CFA. In the present study, the ability of CFA to kill and alter the virulence production in human pathogenic bacteria will offer insights into a new scope for the application of these biomaterials in healthcare to effectively treat bacterial infections.</P>
Dasagrandhi, Chakradhar,Ellamar, Joel B.,Kim, Young Soon,Kim, Hak-Ryul Korean Society of Food Science and Technology 2016 Food Science and Biotechnology Vol.25 No.6
We analyzed the antimicrobial potential of a novel furan fatty acid, 7,10-epoxyoctadeca-7,9-dienoic acid (7,10-EODA) against methicillin-resistant and -sensitive S. aureus (MRSA and MSSA). The anti-staphylococcal activity of 7,10-EODA and its consequences on cell physiology was determined by disc diffusion, broth microdilution, and flow cytometry. Anti-virulence activity of 7,10-EODA was evaluated by bioassays. 7,10-EODA was anti-staphylococcal with minimum inhibitory concentration (MIC) range of 125-250 mg/L. 7,10-EODA exhibited a dose response and inhibited MRSA 01ST001 by 90.5% and ATCC 29213 (MSSA) by 85.3% at 125 mg/L. MIC of 7,10-EODA permeabilized >95 % of MRSA 01ST001 cells to small molecules. Sublethal dose of 7,10-EODA was non-toxic but markedly reduced the hemolytic, coagulase, and autolytic activities of MRSA and MSSA at 15.6 mg/L. The results provide a lead for the utilization of natural furan fatty acids as novel anti-MRSA agents.
( Chakradhar Dasagrandhi ),( Anup Pandith ),( Khalid Imran ) 한국미생물생명공학회(구 한국산업미생물학회) 2020 한국미생물·생명공학회지 Vol.48 No.4
The emergence of multi-drug resistant, pathogenic methicillin-resistant Staphylococcus aureus (MRSA) is a threat to global health and has created a need for novel functional therapeutic agents. In this study, we evaluated the underlying mechanisms of the anti-MRSA effect of an azaphilone pigment, sclerotiorin (SCL) from Penicillium sclerotiorum. The antimicrobial activity of SCL was evaluated using agar disc diffusion, broth microdilution, time-kill assays and biophysical studies. SCL exhibits selective activity against Gram positive bacteria including MRSA (range, MIC = 128-1028 μg/ml) and exhibited rapid bactericidal action against MRSA with a > 4 log reduction in colony forming units within three hours of administration. Biophysical studies, using fluorescent probes and laser or electron microscopy, demonstrated a SCL dose-dependent alternation in membrane potential (62.6 ± 5.0.4% inhibition) and integrity (> 95 ± 2.3%), and the release of UV<sub>260</sub> absorbing materials within 60 min (up to 3.2 fold increase, p < 0.01) of exposure. Further, SCL localized to the cytoplasm and hydrolyzed plasmid DNA. While in vitro checkerboard studies revealed that SCL potentiated the antimicrobial activity of topical antimicrobials such as polymixin, neomycin, and bacitracin (Fractional Inhibitory Concentration Index range, 0.26-0.37). Taken together these results suggest that SCL targets the membrane and DNA of MRSA to facilitate its anti- MRSA antimicrobial effect.
Chakradhar Dasagrandhi,Joel B. Ellamar,김영순,김학렬 한국식품과학회 2016 Food Science and Biotechnology Vol.25 No.6
We analyzed the antimicrobial potential of a novel furan fatty acid, 7,10-epoxyoctadeca-7,9- dienoic acid (7,10-EODA) against methicillin-resistant and -sensitive S. aureus (MRSA and MSSA). The anti-staphylococcal activity of 7,10-EODA and its consequences on cell physiology was determined by disc diffusion, broth microdilution, and flow cytometry. Anti-virulence activity of 7,10-EODA was evaluated by bioassays. 7,10-EODA was anti-staphylococcal with minimum inhibitory concentration (MIC) range of 125-250 mg/L. 7,10-EODA exhibited a dose response and inhibited MRSA 01ST001 by 90.5% and ATCC 29213 (MSSA) by 85.3% at 125 mg/L. MIC of 7,10-EODA permeabilized >95 % of MRSA 01ST001 cells to small molecules. Sublethal dose of 7,10-EODA was non-toxic but markedly reduced the hemolytic, coagulase, and autolytic activities of MRSA and MSSA at 15.6 mg/L. The results provide a lead for the utilization of natural furan fatty acids as novel anti-MRSA agents.
Kim, Deok-Hoon,Dasagrandhi, Chakradhar,Park, Seul-Ki,Eom, Sung-Hwan,Huh, Man-Kyu,Mok, Jong-Soo,Kim, Young-Mog Elsevier 2018 FOOD SCIENCE AND TECHNOLOGY -ZURICH- Vol.90 No.-
<P>Gamma-aminobutyric acid (GAGA) is an important four carbon amino acid known to be involved in the regulation of hypertension, neurotransmission, and stress. Development of functional foods with GABA might impart new health benefits. The present study details about the optimal conditions for the production of GABA using sea tangle (Saccharina japonica) extract (STE). Effect of supplementation of various nutritional factors along with STE on the growth of Lactobacillus brevis BJ-20 and GABA production was investigated. The study suggested that supplementation of nitrogen sources, especially yeast extract at 3% (w/v) with 5 brix STE resulted in significant production of GABA. However, carbohydrates and free amino acids had no significant effect on the GABA production. With optimal conditions, optimal GABA production (76.8 +/- 3.4 mu g/ml) was detected during 108-120 h with 87% glutamate conversion. Also we observed that the GAD genes related with GABA bio-conversion in L. brevis BJ-20 cells were positively regulated in 5 brix STE supplemented with 3% yeast extract. The results of the present study suggested that L. brevis BJ-20 strain can be a resourceful microorganism in developing GABA enriched STE food that can be used as health functional benefits.</P>
Atchudan, Raji,Edison, Thomas Nesakumar Jebakumar Immanuel,Chakradhar, Dasagrandhi,Perumal, Suguna,Shim, Jae-Jin,Lee, Yong Rok Elsevier 2017 Sensors and actuators. B, Chemical Vol.246 No.-
<P><B>Abstract</B></P> <P>Nitrogen-doped carbon dots (N-CDs) were synthesized from <I>Chionanthus retusus (C. retusus)</I> fruit extract using a simple hydrothermal-carbonization method. Their ability to sense metal ions, and their biological activity in terms of cell viability and bioimaging applications were evaluated. The resulting N-CDs were characterized by various physicochemical techniques such as high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and Raman spectroscopy. The optical properties were characterized by ultraviolet visible (UV-vis) fluorescence spectroscopy techniques. The average size of the N-CDs was approximately 5±2nm with an interlayer distance of 0.21nm, as calculated from the HRTEM images. The presence of phytoconstituent functionalities and the percentages of components in the N–CDs were confirmed by XPS studies, and a nitrogen content of 5.3% was detected. The N–CDs demonstrated highly durable fluorescence properties and low cytotoxicity with a quantum yield of 9%. The synthesized N–CDs were then used as probes for the detection of metal ions. The N–CDs exhibited high sensitivity and selectivity towards Fe<SUP>3+</SUP>, with a linear relationship between 0 and 2μM and a detection limit of 70μM. The synthesized N–CDs are anticipated to have diverse biomedical applications, particularly for bioimaging, given their high fluorescence, excellent water solubility, good cell permeability, and negligible cytotoxicity. Finally, the potential of N–CDs as biological probes was investigated using fungal (<I>Candida albicans</I> and <I>Cryptococcus neoformans</I>) strains via fluorescent microscopy. We found that N–CDs were suitable candidates for differential staining applications in yeast cells with good cell permeability, localization with negligible cytotoxicity. Hence, N–CDs may find dual utility as probes for the detection of cellular pools of metal ions (Fe<SUP>3+</SUP>) and also for early detection of opportunistic yeast infections in biological samples.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Durable fluorescent N-CDs prepared using <I>C. Retusus</I> via hydrothermal-carbonization. </LI> <LI> This method of synthesis and N-CDs is an ideal for sensing of Fe<SUP>3+</SUP> and bio-imaging. </LI> <LI> N-CDs was used as a promising fluorescent probe for the direct detection of Fe<SUP>3+</SUP>. </LI> <LI> N-CDs were used as selective probes for yeast <I>C. albicans</I> and <I>C. neoformans</I>. </LI> <LI> N-CDs exhibits selective uptake, good biocompatibility and negligible cytotoxicity. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>