Inhibitory effects of the natural product esculetin on Phytophthora capsici and its possible mechanism

Esculetin is an important plant-derived natural product that has multiple bioactivities and applications. Phytophthora capsici is a notorious plant pathogen capable of infecting a broad range of hosts. In this study, we evaluated the antifungal activity of esculetin against P. capsici. The baseline sensitivity of P. capsici to esculetin was established using 108 isolates collected from various geographical regions in the Jiangsu and Shandong Provinces of China. The median effective concentration (EC50) values for esculetin ranged from 2.08 to 16.46 μg/mL, with a mean of 6.87 ± 2.70 μg/mL, and were normally distributed. Furthermore, both zoospore production and germination were also strongly inhibited by esculetin. Importantly, esculetin exhibited protective as well as curative activities against P. capsici on tomato, and was capable of restricting the early infection of P. capsici on Nicotiana benthamiana. We found that the esculetin treatment led to cell membrane damage of P. capsici, as revealed by morphological observations and measurements of relative conductivity and malondialdehyde (MDA). Finally, our results also suggested esculetin may adversely affect P. capsici by inhibiting its DNA and protein synthesis. These findings will contribute to a broader evaluation of using esculetin to control diseases caused by P. capsici and towards a better understanding of its mode of action as a potential fungicide.

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Sensitivity of Isolates of Phytophthora capsici from the Eastern United States to Fluopicolide

Plant Disease ◽

10.1094/pdis-03-11-0242 ◽

2011 ◽

Vol 95 (11) ◽

pp. 1414-1419 ◽

Cited By ~ 12

Author(s):

Anthony P. Keinath ◽

Chandrasekar S. Kousik

Keyword(s):

United States ◽

North Carolina ◽

South Carolina ◽

Mycelial Growth ◽

Phytophthora Capsici ◽

The United States ◽

Eastern United States ◽

Baseline Sensitivity ◽

First Report ◽

Zoospore Production

Fluopicolide, a pyridinylmethyl-benzamide fungicide, was registered in the United States in 2008 to control diseases caused by Oomycete pathogens, such as Phytophthora capsici, on cucurbit and solanaceous vegetables. The main objective of this study was to determine baseline sensitivity to fluopicolide in isolates of P. capsici from the southeastern and midwestern United States. A total of 69 isolates from Florida (14 isolates), Georgia (14 isolates), Michigan (24 isolates), North Carolina (3 isolates), and South Carolina (17 isolates) that had not been previously exposed to fluopicolide were grown on fungicide-amended medium to determine sensitivity of mycelia, sporangia, and zoospores to the fungicide. All isolates of P. capsici tested (range of 54 to 69 isolates per assay) were sensitive to fluopicolide in all four assays. The median EC50 fluopicolide concentration was 0.22, 2.08, 0.048, and 0.10 mg/liter in the mycelial growth, zoospore germination, sporangia production, and zoospore production assays, respectively. For mycelial growth and zoospore germination, isolates from Michigan had a higher mean EC50 value than isolates from the four southeastern states. This is the first report of variation in baseline sensitivity to a fungicide by P. capsici isolates from different regions of the United States. In the sporangia production and zoospore production assays, isolates from different states did not differ in sensitivity. Single rates of fluopicolide were tested with additional isolates to validate discriminatory rates for monitoring sensitivity. A concentration of 0.3 or 1.0 mg/liter is recommended for mycelial growth, and 0.1 mg/liter is recommended for sporangia and zoospore production.

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Baseline Sensitivity and Resistance-Risk Assessment of Phytophthora capsici to Iprovalicarb

Phytopathology ◽

10.1094/phyto-12-09-0351 ◽

2010 ◽

Vol 100 (11) ◽

pp. 1162-1168 ◽

Cited By ~ 23

Author(s):

Xiao Hong Lu ◽

Shu Sheng Zhu ◽

Yang Bi ◽

Xi Li Liu ◽

Jianjun J. Hao

Keyword(s):

Mycelial Growth ◽

Phytophthora Capsici ◽

Acid Amide ◽

Resistance Management ◽

Cross Resistance ◽

Baseline Sensitivity ◽

Resistance Risk ◽

Zoospore Production ◽

Caa Fungicides ◽

Growth Characters

Iprovalicarb has been used to control Phytophthora capsici, a devastating pathogen of many economically important crops. To evaluate the risk of fungicide resistance, 158 isolates of P. capsici were examined for sensitivity to iprovalicarb by measuring mycelial growth. Values of effective concentrations for 50% mycelial growth inhibition varied from 0.2042 to 0.5540 μg/ml and averaged 0.3923 (±0.0552) μg/ml, with a unimodal distribution. This is the first report of P. capsici isolates highly resistant to iprovalicarb (resistance factor >100). Resistance of the isolates was stable through 10 transfers on iprovalicarb-free medium, and most resistant isolates had the same level of fitness (mycelial growth, zoospore production, and virulence) as their corresponding parents, indicating that iprovalicarb resistance was independent from other general growth characters. There was cross-resistance among all tested carboxylic acid amide (CAA) fungicides, including iprovalicarb, flumorph, dimethomorph, and mandipropamid, but not with non-CAA fungicides, including azoxystrobin, chlorothalonil, cymoxanil, etridiazole, metalaxyl, and zoxamide. Based on the present results, resistance risk of P. capsici to CAAs could be moderate and resistance management should be considered.

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Wild Type Sensitivity and Mutation Analysis for Resistance Risk to Fluopicolide in Phytophthora capsici

Plant Disease ◽

10.1094/pdis-05-11-0372 ◽

2011 ◽

Vol 95 (12) ◽

pp. 1535-1541 ◽

Cited By ~ 20

Author(s):

Xiao Hong Lu ◽

Mary K. Hausbeck ◽

Xi Li Liu ◽

Jianjun J. Hao

Keyword(s):

Phytophthora Capsici ◽

The United States ◽

Fruit Rot ◽

Cross Resistance ◽

Wild Type ◽

Baseline Sensitivity ◽

Resistance Risk ◽

Crown Root ◽

Zoospore Production ◽

Resistant Mutants

Crown, root, and fruit rot caused by Phytophthora capsici is an increasing problem for vegetable growers in Michigan and the United States. The newly registered fungicide fluopicolide is effective to limit crop loss but the potential for P. capsici to develop resistance is not well known. A laboratory study assessed the risk of P. capsici developing resistance to fluopicolide. Baseline sensitivity to fluopicolide was determined using 126 P. capsici Michigan isolates. Values of effective concentrations for 50% inhibition of mycelial growth ranged from 0.08 to 0.24 μg/ml and were distributed as a unimodal curve, indicating that all isolates were sensitive to fluopicolide. Mutants resistant to fluopicolide were obtained from five isolates by screening zoospores on fluopicolide-amended (5 μg/ml) media at a mutation frequency above 1.0 × 10–7. The mutant isolates were clustered with either intermediate (resistance factor [RF] = 3.53 to 77.91) or high (RF = 2481.40 to 7034.79) resistance. Resistance was stable through 10 mycelial transfers on fungicide-free medium. All resistant mutants showed similar fitness in zoospore production, cyst germination, and virulence compared with their sensitive parents, with few exceptions. No cross-resistance was detected between fluopicolide and five other fungicides. There could be a moderately high risk of field populations of P. capsici developing resistance to fluopicolide, and populations should be monitored.

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Identification and Target-Modification of SL-BBI: A Novel Bowman–Birk Type Trypsin Inhibitor from Sylvirana latouchii

Biomolecules ◽

10.3390/biom10091254 ◽

2020 ◽

Vol 10 (9) ◽

pp. 1254 ◽

Cited By ~ 1

Author(s):

Xi Chen ◽

Dong Chen ◽

Linyuan Huang ◽

Xiaoling Chen ◽

Mei Zhou ◽

...

Keyword(s):

Antimicrobial Activity ◽

Trypsin Inhibitor ◽

Inhibitory Activity ◽

Membrane Damage ◽

Antiproliferative Effects ◽

Docking Simulations ◽

Cell Membrane Damage ◽

Action Mode ◽

Trypsin Inhibition ◽

Cloning Method

The peptides from the ranacyclin family share similar active disulphide loop with plant-derived Bowman–Birk type inhibitors, some of which have the dual activities of trypsin inhibition and antimicrobial. Herein, a novel Bowman–Birk type trypsin inhibitor of the ranacyclin family was identified from the skin secretion of broad-folded frog (Sylvirana latouchii) by molecular cloning method and named as SL-BBI. After chemical synthesis, it was proved to be a potent inhibitor of trypsin with a Ki value of 230.5 nM and showed weak antimicrobial activity against tested microorganisms. Modified analogue K-SL maintains the original inhibitory activity with a Ki value of 77.27 nM while enhancing the antimicrobial activity. After the substitution of active P1 site to phenylalanine and P2′ site to isoleucine, F-SL regenerated its inhibitory activity on chymotrypsin with a Ki value of 309.3 nM and exhibited antiproliferative effects on PC-3, MCF-7 and a series of non-small cell lung cancer cell lines without cell membrane damage. The affinity of F-SL for the β subunits in the yeast 20S proteasome showed by molecular docking simulations enriched the understanding of the possible action mode of Bowman–Birk type inhibitors. Further mechanistic studies have shown that F-SL can activate caspase 3/7 in H157 cells and induce apoptosis, which means it has the potential to become an anticancer agent.

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Particle Size of Drug Nanocarriers Defines the Fate of Spinal Cord Injury’s Recovery

10.21203/rs.3.rs-530238/v1 ◽

2021 ◽

Author(s):

Delaram Poormoghadam ◽

Bita Rasoulian Shiadeh ◽

Fereshte Azedi ◽

Hani Tavakol ◽

Seyed Mahdi Rezayat ◽

...

Keyword(s):

Spinal Cord ◽

Cell Membrane ◽

Muscular Atrophy ◽

Muscle Tone ◽

Membrane Damage ◽

Definitive Treatment ◽

Detrusor Muscle ◽

Cell Membrane Damage ◽

Fty 720 ◽

Cord Injury

Abstract Spinal cord injury (SCI) is a debilitating condition for which no definitive treatment has yet been identified. Noteworthy, it influences other tissues through inflammatory reactions and metabolic disturbance. Therefore, fingolimod (FTY-720) as an FDA-approved inflammatory modulator would be promising. In the present study, nanocarriers at two distinct monodisperse particle sizes of 60 (nF60) and 190 (nF190) nm were prepared.The neural stem cell (NSC) viability and LDH release were studied in the face of the nanocarriers and free FTY-720. Results indicated that nanocarriers and free FTY-720 enhanced NSC viability than the control group.However, nF190 significantly induced less cell membrane damage than nF60. Nanocarriers and free FTY-720 enhanced motor neuron recovery in SCI rats, while body weight and return to bladder reflux by nF190 was significantly higher than nF60 groups. Return to bladder reflux might be due to the role of FTY-720 in regulation of detrusor muscle tone and preservation of the integrity of vessels by acting on endothelial cells. Moreover,nF190 gained higher soleus muscle weight than the free drugs;probably decreasing pro-inflammatory cytokines in soleus diminish muscular atrophy in SCI rats.To sum thing up, larger nanacarrirs with less cell membrane damage seems to be more efficient than smaller ones to manage SCI.

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Surface chemistry modification of silica nanoparticles alters the activation of monocytes

Therapeutic Delivery ◽

10.4155/tde-2021-0006 ◽

2021 ◽

Author(s):

Romina Mitarotonda ◽

Martín Saraceno ◽

Marcos Todone ◽

Exequiel Giorgi ◽

Emilio L Malchiodi ◽

...

Keyword(s):

Flow Cytometry ◽

Immune System ◽

Cell Membrane ◽

Cell Activation ◽

Membrane Damage ◽

Living Cells ◽

Cell Membrane Damage ◽

Study Materials ◽

Therapeutic Molecules ◽

Pro Inflammatory Cytokines

Aim: Nanoparticles (NPs) interaction with immune system is a growing topic of study. Materials & methods: Bare and amine grafted silica NPs effects on monocytes/macrophages cells were analyzed by flow cytometry, MTT test and LIVE/DEAD® viability/cytotoxicity assay. Results: Bare silica NPs inhibited proliferation and induced monocyte/macrophages activation (increasing CD40/CD80 expression besides pro-inflammatory cytokines and nitrite secretion). Furthermore, silica NPs increased cell membrane damage and reduced the number of living cells. In contrast, amine grafted silica NPs did not alter these parameters. Conclusion: Cell activation properties of bare silica NPs could be hindered after grafting with amine moieties. This strategy is useful to tune the immune system stimulation by NPs or to design NPs suitable to transport therapeutic molecules.

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In Vitro Anti-Biofilm Activity of Hydrogen-Peroxide Generating Electrochemical Bandage Against Yeast Biofilms

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01792-21 ◽

2021 ◽

Author(s):

Yash S. Raval ◽

Abdelrhman Mohamed ◽

Jayawant N. Mandrekar ◽

Cody Fisher ◽

Kerryl E. Greenwood-Quaintance ◽

...

Keyword(s):

Membrane Damage ◽

Microscopic Analysis ◽

Viable Cell ◽

Wound Infections ◽

Unique Challenge ◽

Cell Membrane Damage ◽

Cell Counts ◽

Extensive Cell ◽

Fluorescence Microscopic Analysis

Wound infections are caused by bacteria and/or fungi. The presence of fungal biofilms in wound beds presents a unique challenge, as fungal biofilms may be difficult to eradicate. The goal of this work was to assess the in vitro anti-biofilm activity of a H 2 O 2 -producing electrochemical bandage (e-bandage) against 15 yeast isolates representing commonly-encountered species. Time-dependent decreases in viable biofilm CFU counts of all isolates tested were observed, resulting in no visible colonies with 48 hours of exposure by plate culture. Fluorescence microscopic analysis showed extensive cell membrane damage of biofilm cells after e-bandage treatment. Reductions in intracellular ATP levels of yeast biofilm cells were recorded post e-bandage treatment. Our results suggest that exposure to H 2 O 2 -producing e-bandages reduce in vitro viable cell counts of yeast biofilms, making this a potential new topical treatment approach for fungal wound infections.

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