scholarly journals Hormetic Effects of Flusilazole Preconditioning on Mycelial Growth and Virulence of Sclerotinia sclerotiorum

Plant Disease ◽  
2018 ◽  
Vol 102 (6) ◽  
pp. 1165-1170 ◽  
Author(s):  
Xiaoming Lu ◽  
Shun He ◽  
Hongju Ma ◽  
Jianhong Li ◽  
Fuxing Zhu
Keyword(s):  
Sclerotinia Sclerotiorum ◽  
Mycelial Growth ◽  
Dose Range ◽  
Pathogenic Fungi ◽  
Phytopathogenic Fungi ◽  
Dependent Manner ◽  
Inhibitory Effects ◽  
Mycelia Growth ◽  
Dmi Fungicides ◽  
Dose Dependent

Hormetic effects of fungicides are highly relevant to fungicide applications and management of plant-pathogenic fungi. Preconditioning (i.e., early exposure to relatively low doses of a toxicant) is a special form of hormesis, and fungicide preconditioning of phytopathogenic fungi is inevitable in the field. The present study showed that spraying the demethylation inhibitor (DMI) fungicide flusilazole at 0.1 µg/ml had stimulatory effects on the virulence of Sclerotinia sclerotiorum inoculated at 1 and 24 h after spraying. Flusilazole sprayed at 10 µg/ml showed inhibitory effects on the virulence of S. sclerotiorum inoculated during the first 3 days after spraying. Inoculations on the 5th, 7th, and 10th day after spraying did not show any significant inhibitory or stimulatory effects on the virulence. After growing for 2 days on potato dextrose agar (PDA) amended with flusilazole at a dose range from 0.0005 to 0.25 µg/ml as preconditioning treatments, mycelia were transferred onto PDA without fungicide and subsequent mycelial growth was slower than the nonpreconditioned control. However, after the preconditioned colonies were transferred onto PDA supplemented with flusilazole at 0.2 µg/ml, percent stimulations of mycelia growth compared with the control had a parabolic shape across the preconditioning flusilazole concentration range. Similarly, the mycelial growth of the preconditioned mycelial plugs on PDA amended with other DMI fungicides (prochloraz or tebuconazole) also showed a typical hormetic response, whereas mycelial growth on PDA amended with carbendazim or dimethachlone was inhibited in a dose-dependent manner. Preconditioning S. sclerotiorum with flusilazole on rapeseed plants elicited virulence stimulations in a dose-dependent manner similar to those on mycelial growth on PDA. After disease lesions developed on rapeseed leaves sprayed with flusilazole as the preconditioning treatment were inoculated onto rapeseed plants, virulence was inhibited on leaves without fungicide or sprayed with carbendazim or dimethachlone compared with the nonpreconditioned control, whereas virulence was stimulated on leaves sprayed with flusilazole, prochloraz, or tebuconazole, and the maximum percent stimulation was 10.2%. These results will advance our understanding of hormetic effects of fungicides and of preconditioning hormesis in particular.

scholarly journals Activity of Alkanediol Alkanoates against Pathogenic Plant Fungi Rhizoctonia solani and Sclerotium rolfsii

2012 ◽  
Vol 7 (9) ◽  
pp. 1934578X1200700 ◽  
Author(s):  
Paraj Shukla ◽  
Suresh Walia ◽  
Vivek Ahluwalia ◽  
Balraj S. Parmar ◽  
Muraleedharan G. Nair
Keyword(s):  
Antifungal Activity ◽  
Ethylene Glycol ◽  
Rhizoctonia Solani ◽  
Diethylene Glycol ◽  
Sclerotium Rolfsii ◽  
Phytopathogenic Fungi ◽  
Dependent Manner ◽  
Acyl Chlorides ◽  
Mass Spectral ◽  
Dose Dependent

Thirty known dialkanoates of ethylene, propylene and diethylene glycols were synthesized by reacting the glycols with acyl chlorides and their structures confirmed by IR, NMR and mass spectral analyses. They exhibited significant antifungal activity against two phytopathogenic fungi Rhizoctonia solani Kuehn and Sclerotium rolfsii Sacc in a dose dependent manner. Propylene glycol dipentanoate was the most active against R. solani. followed by diethylene glycol dibutanoate and ethylene glycol dibutanoate. Against S. rolfsii ethylene glycol diheptanoate was found to be most active followed by diethylene glycol diisobutanoate As compared to the standard reference benomyl (EC50 5.16 μg/mL), the potential alkanediol dialkanoates showed EC50 in the range of 33 – 60 μg/mL.

scholarly journals Stimulatory Effects of Sublethal Doses of Dimethachlon on Sclerotinia sclerotiorum

Plant Disease ◽  
2014 ◽  
Vol 98 (10) ◽  
pp. 1364-1370 ◽  
Author(s):  
Feng Zhou ◽  
Hong-Jie Liang ◽  
Ya-Li Di ◽  
Hong You ◽  
Fu-Xing Zhu
Keyword(s):  
Oilseed Rape ◽  
Sclerotinia Sclerotiorum ◽  
Mycelial Growth ◽  
Plant Disease ◽  
Pathogenic Fungi ◽  
Potato Dextrose Agar ◽  
Detached Leaves ◽  
Sublethal Doses ◽  
Fungal Phytopathogens ◽  
Plant Disease Management

Growth and virulence stimulations of sublethal doses of fungicides on plant-pathogenic fungi and oomycetes have been reported and the stimulatory effects are potentially relevant to plant disease management. Sclerotinia sclerotiorum is one of the most devastating and economically important necrotrophic fungal phytopathogens, capable of infecting more than 400 species of plants worldwide. In order to study stimulatory effects of sublethal doses of fungicides on S. sclerotiorum, 55 dimethachlon-sensitive isolates and 3 dimethachlon-resistant isolates of S. sclerotiorum were assayed to determine effects of sublethal doses of dimethachlon on mycelial growth rate on potato dextrose agar (PDA) media and virulence on oilseed rape plants. Results showed that all 3 dimethachlon-resistant isolates and 13 of the 55 sensitive isolates exhibited stimulatory responses to sublethal doses of dimethachlon. Dimethachlon-resistant isolates grew significantly (P < 0.05) faster on PDA media amended with dimethachlon at 0.5 to 4 μg/ml than on fungicide-free PDA media. As for virulence on detached leaves of oilseed rape plants, lesion diameters of dimethachlon-resistant isolates after growth on PDA media amended with dimethachlon at 0.5 to 2 μg/ml were significantly larger (P < 0.05) than the control. The maximum stimulatory effects were 42.40 to 59.80%. In pot experiments, for both dimethachlon-sensitive and -resistant isolates, significant (P < 0.05) virulence stimulations were observed after spraying with dimethachlon at a concentration of 2 μg/ml. After growing on dimethachlon-amended PDA media, H2O2 sensitivity of S. sclerotiorum decreased significantly (P < 0.05) compared with the nonamended PDA control.

scholarly journals BIOLOGICAL CONTROL OF PHYTOPATHOGENIC FUNGI USING DIFFERENT EXTRACTS OF CHAETOMIUM CUPREUM

2018 ◽  
Vol 11 (9) ◽  
pp. 328
Author(s):  
Sharmila Tirumale ◽  
Nazir Wani
Keyword(s):  
Ethyl Acetate ◽  
Mycelial Growth ◽  
Ethyl Acetate Extract ◽  
Pathogenic Fungi ◽  
Phytopathogenic Fungi ◽  
Plant Pathogenic Fungi ◽  
Purification And Characterization ◽  
Butanol Extract ◽  
Ethyl Acetate Extracts

Objective: This study evaluated the Chaetomium cupreum extracts as biocontrol agents against four plant pathogenic fungi (Cladosporium cladosporioides, Fusarium oxysporum, Phomopsis azadirachtae, and Rhizoctonia solani).Method: The antifungal activity of n-butanol and ethyl acetate extracts of C. cupreum was evaluated against plant pathogenic fungi using food poison method.Result: In n-butanol extract, the percentage inhibition of mycelial growth against C. cladosporoides was 88.3±0.1, F. oxysporum was 59.4±0.2, R. solani was 56.2±0.9, and P. azadirachtae was 52.0±0.1at 0.25 mg/ml, respectively. In ethyl acetate extract, the percentage inhibition of mycelial growth against C. cladosporoides was 86.0±0.5, F. oxysporum was 66.4±0.1, P. azadirachtae was 55.2±0.9, and R. solani was 52.0±0.1 at 0.25 mg/ml, respectively.Conclusion: It was found that n-butanol extract is more effective than ethyl acetate extract of C. cupreum. Future studies will focus on the purification and characterization of compounds of C. cupreum and their biocontrol capacity with the mechanism for plant pathological applications.

Activation of Phosphatidylinositol-Linked Novel D1 Dopamine Receptors Inhibits High-Voltage-Activated Ca2+ Currents in Primary Cultured Striatal Neurons

2009 ◽  
Vol 101 (5) ◽  
pp. 2230-2238 ◽  
Author(s):  
Li-Qun Ma ◽  
Chao Liu ◽  
Fang Wang ◽  
Na Xie ◽  
Jun Gu ◽  
...  
Keyword(s):  
Dopamine Receptor ◽  
High Voltage ◽  
Dependent Manner ◽  
Striatal Neurons ◽  
Inhibitory Effects ◽  
Patch Clamp Technique ◽  
Whole Cell Patch Clamp ◽  
Intracellular Ca ◽  
Dose Dependent

Recent evidences indicate the existence of a putative novel phosphatidylinositol (PI)-linked D1 dopamine receptor that mediates excellent anti-Parkinsonian but less severe dyskinesia action. To further understand the basic physiological function of this receptor in brain, the effects of a PI-linked D1 dopamine receptor-selective agonist 6-chloro-7,8-dihydroxy-3-methyl-1-(3-methylphenyl)-2,3,4,5-tetrahydro-1H-3-benzazepine (SKF83959) on high-voltage activated (HVA) Ca2+ currents in primary cultured striatal neurons were investigated by whole cell patch-clamp technique. The results indicated that stimulation by SKF83959 induced an inhibition of HVA Ca2+ currents in a dose-dependent manner in substance-P (SP)-immunoreactive striatal neurons. Application of D1 receptor, but not D2, α1 adrenergic, 5-HT receptor, or cholinoceptor antagonist prevented SKF83959-induced reduction, indicating that a D1 receptor-mediated event assumed via PI-linked D1 receptor. SKF83959-induced inhibitory modulation was mediated by activation of phospholipase C (PLC), mobilization of intracellular Ca2+ stores and activation of calcineurin. Furthermore, the inhibitory effects were attenuated significantly by the L-type calcium channel antagonist nifedipine, suggesting that L-type calcium channels involved in the regulation induced by SKF83959. These findings may help to further understand the functional role of the PI-linked dopamine receptor in brain.

scholarly journals The Effects of Salacia reticulata on Anti-Cellular Oxidants and Melanogenesis Inhibition in α-MSH-stimulated and UV Irradiated B16 Melanoma Cells

2014 ◽  
Vol 9 (4) ◽  
pp. 1934578X1400900
Author(s):  
Prasit Sirwannalert ◽  
Ryusho Kariya ◽  
Ikuko Suzu ◽  
Seiji Okada
Keyword(s):  
Melanoma Cells ◽  
Pharmaceutical Products ◽  
B16 Melanoma ◽  
Tyrosinase Activity ◽  
Root Extract ◽  
Dependent Manner ◽  
Inhibitory Effects ◽  
B16 Melanoma Cells ◽  
Dose Dependent ◽  
Salacia Reticulata

The purposes of this study were to investigate the inhibitory effects of Salacia reticulata Tul. root extract on cellular oxidants and melanogenesis in B16 melanoma cells. Cells treated with non-toxic doses of S. reticulata root extract were investigated for their effects on melanogenesis, cellular tyrosinase activity and cellular oxidant scavenging activity. The results indicated that S. reticulata extract inhibited melanin synthesis and tyrosinase activity in α-MSH-induced or UV-irradiated B16 melanoma cells in a dose dependent manner. Additionally, the extract also exhibited anti-cellular oxidants in UV-induced radical melanoma cells. Altogether, these results suggested that S. reticulata root extract has roles in suppression of melanogenesis and oxidant inhibition. S. reticulata root extract may be a potential source for the development of pharmaceutical products for treatment of skin hyperpigmentation disorders.

Interaction between perchlorate and nifedipine on insulin secretion from mouse pancreastic islets

1993 ◽  
Vol 13 (2) ◽  
pp. 107-117 ◽  
Author(s):  
Gerd Larsson-Nyrén ◽  
Janove Sehlin
Keyword(s):  
Insulin Secretion ◽  
Insulin Release ◽  
Specific Effect ◽  
Maximum Effect ◽  
Dependent Manner ◽  
Inhibitory Effects ◽  
Maximum Inhibition ◽  
Second Phases ◽  
Dose Dependent ◽  
Higher Sensitivity

In order to elucidate the mechanisms responsible for the stimulatory effect of perchlorate (ClO4−) on insulin secretion, we have investigated the interaction between this chaotropic anion and the organic calcium antagonist nifedipine. This drug, known as a blocker of L-type calcium channels, was chosen as a tool to test the idea that ClO4− acts on insulin secretion by stimulating the gating of voltage-controlled Ca2+ channels. ClO4− amplified the stimulatory effect of D-glucose on insulin release from perfused pancreas (first and second phases) as well as from isolated islets incubated in static incubations for 60 min. This indicates that ClO4− amplifies physiologically regulated insulin secretion. Nifedipine reduced D-glucose-induced (20 mM) insulin release in a dose-dependent manner with half-maximum effect at about 0.8 μM and apparent maximum effect at 5 μM nifedipine. In the presence of 20 mM D-glucose, the inhibitory effects of 0.5, 1 or 5 μM nifedipine were only slightly, if at all, counteracted by perchlorate. When 12 mM ClO4− and 20 mM D-glucose were combined, calculation of the specific effect of ClO4− revealed that nifedipine produced almost maximum inhibition already at 0.05 μM. Thus, the perchlorate-induced amplification of D-glucose-stimulated insulin release shows higher sensitivity to nifedipine than the D-glucose-effect as such. This supports the hypothesis that perchlorate primarily affects the voltage-sensitive L-type calcium channel in the β-cell.

scholarly journals Towards Al3+-Induced Manganese-Containing Superoxide Dismutase Inactivation and Conformational Changes: An Integrating Study with Docking Simulations

2011 ◽  
Vol 2011 ◽  
pp. 1-7
Author(s):  
Jiang-Liu Yang ◽  
Shang-Jun Yin ◽  
Yue-Xiu Si ◽  
Zhi-Rong Lü ◽  
Xiangrong Shao ◽  
...  
Keyword(s):  
Superoxide Dismutase ◽  
Conformational Changes ◽  
Tertiary Structure ◽  
Kinetic Studies ◽  
Computational Prediction ◽  
Enzyme Inactivation ◽  
Dependent Manner ◽  
Inhibitory Effects ◽  
Docking Simulations ◽  
Dose Dependent

Superoxide dismutase (SOD, EC 1.15.1.1) plays an important antioxidant defense role in skins exposed to oxygen. We studied the inhibitory effects of Al3+ on the activity and conformation of manganese-containing SOD (Mn-SOD). Mn-SOD was significantly inactivated by Al3+ in a dose-dependent manner. The kinetic studies showed that Al3+ inactivated Mn-SOD follows the first-order reaction. Al3+ increased the degree of secondary structure of Mn-SOD and also disrupted the tertiary structure of Mn-SOD, which directly resulted in enzyme inactivation. We further simulated the docking between Mn-SOD and Al3+ (binding energy for Dock 6.3: −14.07 kcal/mol) and suggested that ASP152 and GLU157 residues were predicted to interact with Al3+, which are not located in the Mn-contained active site. Our results provide insight into the inactivation of Mn-SOD during unfolding in the presence of Al3+ and allow us to describe a ligand binding via inhibition kinetics combined with the computational prediction.

scholarly journals Kinetics of Mushroom Tyrosinase and Melanogenesis Inhibition byN-Acetyl-pentapeptides

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Ching-Yi Lien ◽  
Ching-Yu Chen ◽  
Shih-Ting Lai ◽  
Chin-Feng Chan
Keyword(s):  
Kojic Acid ◽  
Lag Time ◽  
Melanoma Cells ◽  
Dependent Manner ◽  
Mushroom Tyrosinase ◽  
Inhibitory Effects ◽  
B16f10 Melanoma ◽  
B16f10 Melanoma Cells ◽  
Kinetics Of ◽  
Dose Dependent

We investigated the kinetics of 4N-acetyl-pentapeptides, Ac-P1, Ac-P2, Ac-P3, and Ac-P4, regarding inhibition of mushroom tyrosinase activity. The peptides sequences of Ac-P1, Ac-P2, Ac-P3, and Ac-P4 were Ac-RSRFK, Ac-KSRFR, Ac-KSSFR, and Ac-RSRFS, respectively. The 4N-acetyl-pentapeptides were able to reduce the oxidation ofL-DOPA by tyrosinase in a dose-dependent manner. Of the 4N-acetyl-pentapeptides, only Ac-P4 exhibited lag time (80 s) at a concentration of 0.5 mg/mL. The tyrosinase inhibitory effects of Ac-P4 (IC500.29 mg/mL) were more effective than those of Ac-P1, Ac-P2, and Ac-P3, in which IC50s were 0.75 mg/mL, 0.78 mg/mL, and 0.81 mg/mL, respectively. Kinetic analysis demonstrated that all 4N-acetyl-pentapeptides were mixed-type tyrosinase inhibitors. Furthermore, 0.1 mg/mL of Ac-P4 exhibited significant melanogenesis inhibition on B16F10 melanoma cells and was more effective than kojic acid. The melanogenesis inhibition of Ac-P4 was dose-dependent and did not induce any cytotoxicity on B16F10 melanoma cells.

scholarly journals Expression of the Histidine Kinase Gene Sshk Correlates with Dimethachlone Resistance in Sclerotinia sclerotiorum

2019 ◽  
Vol 109 (3) ◽  
pp. 395-401 ◽  
Author(s):  
Jinli Li ◽  
Fuxing Zhu ◽  
Jianhong Li
Keyword(s):  
Cell Wall ◽  
Sclerotinia Sclerotiorum ◽  
Mycelial Growth ◽  
Sodium Dodecyl ◽  
Pathogenic Fungi ◽  
Kinase Gene ◽  
Group Iii ◽  
Major Mechanism ◽  
Increased Sensitivity ◽  
Sclerotium Production

Histidine kinases (HK) are implicated in virulence, vegetative mycelial growth, and osmotic and oxidative responses in pathogenic fungi. Our previous work showed that transcriptional levels of the group III HK gene Sshk are higher in field dimethachlone-resistant isolates of Sclerotinia sclerotiorum compared with sensitive isolates. However, it is not clear whether the overexpression of Sshk is the major mechanism for resistance to dimethachlone. In this study, we constructed Sshk silencing and overexpression vectors and assessed dimethachlone resistance levels, virulence, mycelial growth, and sensitivity to osmotic stress for the Sshk-silenced and -overexpression transformants. Overexpression of Sshk resulted in resistance to dimethachlone and increased sensitivity to various stresses and to the cell-wall-perturbing agents sodium dodecyl sulfate (SDS) and Congo red (CR). Compared with the parent isolate, Sshk-silenced transformants had reduced resistance to dimethachlone, significantly higher (P < 0.05) mycelial growth and virulence, and lower sclerotium production, and were less sensitive to various exogenous stresses such as sodium chloride. Compared with the parent sensitive isolate HLJMG1, dimethachlone resistance ratios of the three overexpression transformants ∆C101, ∆C21, and ∆C10 increased 168.1-, 189.5-, and 221.2-fold, respectively. The three overexpression transformants were more sensitive to CR and SDS than their parent isolate. These findings suggest that overexpression of Sshk is a major mechanism for dimethachlone resistance in some isolates of S. sclerotiorum, and that Sshk plays an important role in maintaining the integrity of the cell wall. Our findings reveal a novel molecular mechanism for dimethachlone resistance in plant-pathogenic fungi.

scholarly journals Histostereological Restorative and Inhibitory Effects of Crude Methanolic Bark Extract of Prunus Africanus on Testosterone-Induced Benign Prostatic Hyperplasia in Wistar Rats

2021 ◽  
pp. 49-61
Author(s):  
Kanyoni J. Mwangi ◽  
Kweri J. Kariuki ◽  
Mwangi A. Warimu ◽  
Bett S. Kipyegon ◽  
Sigei C. Chepngeno ◽  
...  
Keyword(s):  
Benign Prostatic Hyperplasia ◽  
Wistar Rats ◽  
Prostate Volume ◽  
Dose Range ◽  
Study Groups ◽  
Prostatic Hyperplasia ◽  
Bark Extract ◽  
Inhibitory Effects ◽  
Group A ◽  
Dose Dependent

Aim: To evaluate the histostereological effects of P. africanus on testosterone induced Benign Prostatic Hyperplasia (BPH) in Wistar rats. Place and Duration of Study: The study was carried out for six weeks in Jomo Kenyatta University of Agriculture and Technology. Methodology: A sample size of sixty Wistar were used as the experimental model and they were divided into two study groups of 30 rats in the restorative group and 30 rats in the inhibitory group. Each group was further categorized into 5 control and 25 experimental rats. The experimental rats were further subdivided into 5 sub-groups based on varying doses of the crude methanolic bark extract of P. africanus (0 mg, 25 mg, 50 mg, 125 mg, and 200 mg). BPH in experimental animal was induced by subcutaneous injection of testosterone propionate (7.5 mg/kg) for 10 days. Results: The findings of the study showed that the restorative group had a statistical significant (P<0.05) ((dose dependent reduction of the prostate volume, the stromal and epithelium volume was observed. While in the inhibitory group a statistical significant (P<0.05) dose-related inhibition, in the increase of the prostate volume, the stromal and epithelium volume was observed. In conclusion, the maximal restorative effect was observed to be up to 85.6% and at a dose of 200 mg, while the optimal inhibitory effects were observed to be between 66.7- 68.4% in the dose range of 100-200 mg/kg/body weight. Conclusion: Crude methanolic bark extract of P. africanus has both restorative.

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