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( 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.
Complexity Issues of Perfect Roman Domination in Graphs
Chakradhar, Padamutham,Reddy, Palagiri Venkata Subba Department of Mathematics 2021 Kyungpook mathematical journal Vol.61 No.3
For a simple, undirected graph G = (V, E), a perfect Roman dominating function (PRDF) f : V → {0, 1, 2} has the property that, every vertex u with f(u) = 0 is adjacent to exactly one vertex v for which f(v) = 2. The weight of a PRDF is the sum f(V) = ∑<sub>v∈V</sub> f(v). The minimum weight of a PRDF is called the perfect Roman domination number, denoted by γ<sub>R</sub><sup>P</sup>(G). Given a graph G and a positive integer k, the PRDF problem is to check whether G has a perfect Roman dominating function of weight at most k. In this paper, we first investigate the complexity of PRDF problem for some subclasses of bipartite graphs namely, star convex bipartite graphs and comb convex bipartite graphs. Then we show that PRDF problem is linear time solvable for bounded tree-width graphs, chain graphs and threshold graphs, a subclass of split graphs.
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.
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.
Anti-inflammatory Activity of a Flavonol Glycoside from Tephrosia Spinosa
V. Chakradhar,Y. Hari Babu,S. Ganapaty,Y. Rajendra Prasad,N. Koteswara Rao 한국생약학회 2005 Natural Product Sciences Vol.11 No.2
A rare flavonol glycoside identified as eupalitin-3-O-β-D-glucoside (I) was isolated from Tephrosiaspinosa (Leguminosae) and its anti-inflammatory activity was evaluated against carrageenin induced paw edema.The compound exhibited significant activity when compared to the standard drug indomethacin.
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>
미생물 생변환을 통한 필리핀 너트유로부터 기능성 지방산 7,10-dihydroxy-8(E)-octadecenoic acid 생산
차크라다 다사그란디(Chakradhar Dasangrandhi),조엘 엘라마(Joel B. Ellamar),김영순(Young Soon Kim),김인환(In Hwan Kim),김학렬(Hak-Ryul Kim) 한국식품과학회 2017 한국식품과학회지 Vol.49 No.1
본 연구를 통하여 P. aeruginosa PR3를 이용하여 DOD를 생산하기 위해 저가의 기질로서 필리핀 너트유가 효과적으로 사용될 수 있음을 확인하였으며 배지에 첨가되는 여러 영양인자들의 영향을 조사하여 DOD 생산성을 크게 향상시킬 가능성이 있음도 확인하였다. 따라서 DOD 생산에 이용되는 올레산을 식물성오일로부터 별도의 생산과정을 거쳐 생산하지 않고 식물성오일자체를 직접 기질로 사용함으로서 PR3 균주를 이용하여 고부가가치의 DOD를 효율적으로 생산할 수 있다는 것을 확인하였다. Biocatalytic modification of natural resources can be used to generate novel compounds with specific properties, such as higher viscosity and reactivity. The production of hydroxy fatty acids (HFAs), originally found in low quantities in plants, is a good example of the biocatalytic modification of natural vegetable oils. HFAs show high potential for application in a wide range of industrial products, including resins, waxes, nylons, plastics, lubricants, cosmetics, and additives in coatings and paintings. In a recent study, Pseudomonas aeruginosa strain PR3 was used to produce 7,10- dihydroxy-8(E)-octadecenoic acid (DOD) from oleic acid. This present study focused primarily on the utilization of three natural nut oils obtained from the Philippines -pili nut oil (PNO), palm oil (PO), and virgin coconut oil (VCO)- to produce DOD by P. aeruginosa strain PR3. Strain PR3 produced DOD from PNO and PO only, with PNO being the more efficient substrate. An optimization study to achieve the maximum DOD yield from PNO revealed the optimal incubation time and medium pH to be 48 h and 8.0, respectively. Among the carbon sources tested, fructose was the most efficiently used, with a maximum DOD production of 130 mg/50 mL culture. Urea was the optimal nitrogen source, with a maximum product yield of 165 mg/50 mL culture. The results from this study demonstrated that PNO could be used as an efficient substrate for DOD production by microbial bioconversion.