scholarly journals Allelopathic Effects of Three Herb Species on Phytophthora cinnamomi, a Pathogen Causing Severe Oak Decline in Mediterranean Wood Pastures

Forests ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 285
Author(s):  
Manuela Rodríguez-Romero ◽  
Belén Godoy-Cancho ◽  
Isabel M. Calha ◽  
José António Passarinho ◽  
Ana Cristina Moreira
Keyword(s):  
Phytophthora Cinnamomi ◽  
Raphanus Raphanistrum ◽  
Inhibitory Capacity ◽  
Pathogen Suppression ◽  
Pathogen Populations ◽  
Defensive Chemical ◽  
Chemical Response ◽  
Herb Species

The ability of three herbaceous plants (Diplotaxis tenuifolia (L.) DC., Eruca vesicaria L. and Raphanus raphanistrum L.) from Iberian wood pastures to reduce Phytophthora cinnamomi Rands pathogen populations through allelopathic relationships is studied. The inhibitory capacity of their aqueous root extracts (AREs) on mycelial growth and production of P. cinnamomi reproductive structures is analysed in vitro. In addition, Quercus seedlings were grown in infested by P. cinnamomi-soils and with the presence or absence of allelopathic and susceptible herb species to the pathogen to assess the defensive chemical response of Quercus seedlings through their leaf phenolic compounds. Results show a strong inhibitory capacity of AREs on P. cinnamomi activity in vitro and a protective effect of these herb species on Quercus plants against P. cinnamomi in vivo. D. tenuifolia would be especially suited for biological control in the pathogen suppression.

Adverse Effect of Heparin on Thrombin Inactivation

1975 ◽  
Author(s):  
E. Marciniak
Keyword(s):  
Adverse Effect ◽  
Antithrombin Iii ◽  
Factor Xa ◽  
Binding Properties ◽  
Inhibitory Capacity ◽  
Antithrombin Iii Deficiency ◽  
Final Amount ◽  
Native Plasma

In the presence of heparin thrombin, although fast inactivated, impairs the inhibitory capacity of antithrombin III, in result of which the final amount of neutralized enzyme markedly decreases. This adverse effect of heparin was found during the reaction of purified thrombin with both purified human antithrombin III and native plasma hepariniz purified thrombin with both purified human antithrombin III and native plasma heparinized in vitro or in vivo. In the absence of heparin, at concentration equal to that in normal plasma antithrombin III binds 450 Iowa units of thrombin; in the presence of heparin (at 1 unit concentration) this binding is reduced to 145 thrombin units. A fast depletion of inhibitory capacity is also evident after a stepwise addition of thrombin in small installments into a medium containing antithrombin III and heparin. Portions of enzyme initially added disappear with great velocity; subsequent additions, however, accumulate building up a high thrombin level not seen in the absence of heparin. The escalation of thrombin is reversely proportional to the reacting antithrombin III level, thus especially noticeable in antithrombin III deficient plasma. Residual thrombin left in the presence of heparin disappears at a fast rate upon a new addition of antithrombin III. No decrease in anticoagulant properties of heparin is observed during these interactions. Binding of factor Xa to antithrombin III which reacted with thrombin and heparin is also decreased or abolished.These results indicate that in the presence of heparin thrombin not only exposes rapidly a binding site on the inhibitor, but also causes a further change leading to the deletion of antithrombin III binding properties. This may explain adverse, thrombotic effect of heparin sporadically seen in vivo, and suggests that heparin should be applied with caution in patients with antithrombin III deficiency.

Oxidation of alpha 1-protease inhibitor: role of lipid peroxidation products

1989 ◽  
Vol 66 (5) ◽  
pp. 2211-2215 ◽  
Author(s):  
V. Mohsenin ◽  
J. L. Gee
Keyword(s):  
Lipid Peroxidation ◽  
Fatty Acid ◽  
Linoleic Acid ◽  
Stearic Acid ◽  
Protease Inhibitor ◽  
Alpha Tocopherol ◽  
Inhibitory Capacity ◽  
Buffer Control

Previously we demonstrated that in vivo exposure of humans to NO2 resulted in significant inactivation of alpha 1-protease inhibitor (alpha 1-PI) in the bronchoalveolar lavage fluid. However, alpha 1-PI retains its elastase inhibitory activity in vitro when exposed to 10 times the concentration of NO2 used in vivo. We suggested exogenous oxidants such as O2 and NO2 exert their effect in vivo in part through lipid peroxidation. We investigated the mechanism of inactivation of alpha 1-PI in the presence or absence of lipids under oxidant atmosphere. alpha 1-PI in solutions containing phosphate buffer (control), 0.1 mM stearic acid (saturated fatty acid, 18:0), or 0.1 mM linoleic acid (polyunsaturated fatty acid, 18:2) was exposed to either N2 or NO2 (50 ppm for 4 h). Elastase inhibitory capacity of alpha 1-PI was significantly diminished in the presence of 0.1 mM linoleic acid and under NO2 atmosphere (75 +/- 8% of control, P less than 0.01), whereas there was no change in elastase inhibitory capacity of alpha 1-PI in the presence or absence (buffer only) of 0.1 mM stearic acid under a similar condition (109 +/- 11 and 94 +/- 6%, respectively). The inactivated alpha 1-PI as the result of peroxidized lipid could be reactivated by dithiothreitol and methionine sulfoxide peptide reductase, suggesting oxidation of methionine residue at the elastase inhibitory site. Furthermore the inhibitory effect of peroxidized lipid on alpha 1-PI could be prevented by glutathione and glutathione peroxidase and to some extent by alpha-tocopherol.

scholarly journals Plant Extract Treatments Induce Resistance to Bacterial Spot by Tomato Plants for a Sustainable System

Horticulturae ◽  
2020 ◽  
Vol 6 (2) ◽  
pp. 36
Author(s):  
Kamal A. M. Abo-Elyousr ◽  
Najeeb M. Almasoudi ◽  
Ahmed W. M. Abdelmagid ◽  
Sergio R. Roberto ◽  
Khamis Youssef
Keyword(s):  
Antibacterial Activity ◽  
Plant Extracts ◽  
Integrated Management ◽  
Nerium Oleander ◽  
Bacterial Spot ◽  
Tomato Plants ◽  
Sustainable System ◽  
Pathogen Populations

The aim of this study is to assess the effect of extracts of Nerium oleander, Eucalyptus chamadulonsis and Citrullus colocynthis against bacterial spot disease of tomato and to investigate the induction of resistance by tomato (Solanum lycopersicum) in order to promote a sustainable management system. The antibacterial activity of aqueous and ethanol plant extracts was tested against Xanthomonas axonopodis pv. vesicatoria, isolate PHYXV3, in vitro and in vivo. The highest antibacterial activity in vitro was obtained with C. colocynthis, N. oleander and E. chamadulonsis, respectively. In vivo, ethanol extracts of N. oleander and E. chamadulonsis were more effective than aqueous extracts in reducing pathogen populations on tomato leaves. Under greenhouse conditions, application of the plant extracts at 15% (v/v) to tomato plants significantly reduced disease severity and increased the shoot weight of ‘Super Marmande’ tomato. In most cases, plant extracts significantly increased total phenol and salicylic acid content of tomato plants compared to either healthy or infected ones. In addition, C. colocynthis and E. chamadulonsis extracts significantly increased peroxidase activity while only E. chamadulonsis increased polyphenol oxidase after infection with the causal agent. The results indicated that the plant extracts showed promising antibacterial activity and could be considered an effective tool in integrated management programs for a sustainable system of tomato bacterial spot control.

scholarly journals RhoA knockout fibroblasts lose tumor-inhibitory capacity in vitro and promote tumor growth in vivo

2017 ◽  
Vol 114 (8) ◽  
pp. E1413-E1421 ◽  
Author(s):  
Twana Alkasalias ◽  
Andrey Alexeyenko ◽  
Katharina Hennig ◽  
Frida Danielsson ◽  
Robert Jan Lebbink ◽  
...  
Keyword(s):  
Tumor Growth ◽  
Tumor Cell ◽  
Rho Gtpase ◽  
Focal Adhesions ◽  
Cancer Associated Fibroblasts ◽  
Inhibitory Capacity ◽  
Promote Tumor Growth ◽  
Pc3 Cells

Fibroblasts are a main player in the tumor-inhibitory microenvironment. Upon tumor initiation and progression, fibroblasts can lose their tumor-inhibitory capacity and promote tumor growth. The molecular mechanisms that underlie this switch have not been defined completely. Previously, we identified four proteins overexpressed in cancer-associated fibroblasts and linked to Rho GTPase signaling. Here, we show that knocking out the Ras homolog family member A (RhoA) gene in normal fibroblasts decreased their tumor-inhibitory capacity, as judged by neighbor suppression in vitro and accompanied by promotion of tumor growth in vivo. This also induced PC3 cancer cell motility and increased colony size in 2D cultures. RhoA knockout in fibroblasts induced vimentin intermediate filament reorganization, accompanied by reduced contractile force and increased stiffness of cells. There was also loss of wide F-actin stress fibers and large focal adhesions. In addition, we observed a significant loss of α-smooth muscle actin, which indicates a difference between RhoA knockout fibroblasts and classic cancer-associated fibroblasts. In 3D collagen matrix, RhoA knockout reduced fibroblast branching and meshwork formation and resulted in more compactly clustered tumor-cell colonies in coculture with PC3 cells, which might boost tumor stem-like properties. Coculturing RhoA knockout fibroblasts and PC3 cells induced expression of proinflammatory genes in both. Inflammatory mediators may induce tumor cell stemness. Network enrichment analysis of transcriptomic changes, however, revealed that the Rho signaling pathway per se was significantly triggered only after coculturing with tumor cells. Taken together, our findings in vivo and in vitro indicate that Rho signaling governs the inhibitory effects by fibroblasts on tumor-cell growth.

Extrarenal production and activation of human plasma prorenin: the evidence after venous occlusion

1989 ◽  
Vol 67 (1) ◽  
pp. 59-67 ◽  
Author(s):  
Gregory M. T. Hare ◽  
Arlene Y. Loh ◽  
Daniel H. Osmond
Keyword(s):  
Human Plasma ◽  
Venous Occlusion ◽  
Local Activation ◽  
Active Renin ◽  
Inhibitory Capacity ◽  
Enzyme Systems ◽  
Plasma Active Renin

Venous occlusion of the left arm in consenting men was induced for 10 or 20 min to stimulate local fibrinolytic and other proteases, thereby favouring the conversion of prorenin to renin. Using the two techniques cryoactivation and tryptic activation, we found that plasma active renin increased significantly after such occlusion (10 and 20 min) while prorenin rose more convincingly and progressively from 10 to 20 min. The renin increase can be partially attributed to hemoconcentration, but in vivo production and (or) local activation of prorenin to renin cannot be excluded. The prorenin rise can apparently be attributed to local extrarenal production, and not to hemoconcentration or influx, since it was progressive and neither prorenin nor renin levels were raised at all in blood circulating outside the occluded arm. Prekallikrein and plasminogen levels were elevated in occlusion plasmas, but responsibility of these enzyme systems for any enhanced activation of prorenin was not established. The trypsin inhibitory capacity was also elevated, increasing the requirement of trypsin to achieve optimal activation of prorenin, but not changing the prorenin estimate itself. Thus, prorenin appears to be released extrarenally, within the vasculature of an occluded arm, while in vitro evidence suggests that the mechanisms for its activation were stimulated. The importance of such extrarenal production and activation of prorenin for renin production under other physiological or pathophysiological conditions remains to be determined.Key words: venous occlusion, extrarenal prorenin, production, activation.

scholarly journals Expression and function of ABC-transporter protein ABCB1 correlates with inhibitory capacity of Ruxolitinib in vitro and in vivo

Haematologica ◽  
2015 ◽  
Vol 101 (3) ◽  
pp. e81-e85 ◽  
Author(s):  
C. Ebert ◽  
F. Perner ◽  
D. Wolleschak ◽  
T. M. Schnoder ◽  
T. Fischer ◽  
...  
Keyword(s):  
Abc Transporter ◽  
Transporter Protein ◽  
Inhibitory Capacity ◽  
And Function

scholarly journals In vitro Organic Acid Production and In Vivo Food Pathogen Suppression by Probiotic S. thermophilus and L. bulgaricus

2019 ◽  
Vol 10 ◽  
Author(s):  
Smith Etareri Evivie ◽  
Amro Abdelazez ◽  
Bailiang Li ◽  
Xin Bian ◽  
Wan Li ◽  
...  
Keyword(s):  
Organic Acid ◽  
Acid Production ◽  
Organic Acid Production ◽  
Food Pathogen ◽  
Pathogen Suppression

scholarly journals Assessment of Mycophenolic Acid-induced Immunosuppression: A New Approach

2000 ◽  
Vol 46 (9) ◽  
pp. 1376-1383 ◽  
Author(s):  
Olga Millan ◽  
Federic Oppenheimer ◽  
Merce Brunet ◽  
Jordi Vilardell ◽  
Isabel Rojo ◽  
...  
Keyword(s):  
Cell Line ◽  
Mycophenolic Acid ◽  
Mononuclear Cells ◽  
Renal Transplant Recipients ◽  
Inosine Monophosphate Dehydrogenase ◽  
Peripheral Blood Mononuclear ◽  
Impdh Activity ◽  
Inhibitory Capacity

Abstract Background: Mycophenolic acid (MPA), a metabolite of mycophenolate mofetil (MMF), is an immunosuppressive agent that inhibits inosine monophosphate dehydrogenase (IMPDH), a key enzyme in the ex novo synthesis of GTP. We measured IMPDH activity in peripheral blood mononuclear cells (PBMCs) from MMF-treated patients to evaluate the efficacy of MMF in individual patients. Methods: IMPDH activity was measured by 3H released from [2,8-3H]IMP that had been formed in the cells from added [2,8-3H]hypoxanthine in PBMCs of 35 renal transplant recipients treated with cyclosporin A and corticoids plus MMF: 2 g (n = 10), 1.5 g (n = 7), 1 g (n = 10), or 0 g (n = 8) per day. An alternative method, based on the capacity of the patients’ sera to inhibit spontaneous proliferation of the CEM cell line, was also analyzed. Results: The IMPDH activity of PBMCs in transplanted patients was highly variable. For the method based on CEM cell line proliferation: (a) cell proliferation was inhibited only in MMF-treated patients; (b) there was a clear postdose increase in inhibition; (c) inhibition was not affected by other immunosuppressants in vitro or in vivo; (d) inhibition from predose to predose sample was correlated; and (e) when the MMF dosage was <20 mg · kg−1 · day−1, two groups of patients were identified, one that maintained a high inhibitory capacity in all dose intervals, and one with periods of low inhibitory capacity. Conclusions: Measurement of the inhibition of CEM cell line proliferation by sera from MMF-treated patients may be useful for evaluating the relative efficacy of MMF treatment in individual patients, especially those receiving low doses of MMF.

scholarly journals Mefenoxam Sensitivity in Phytophthora cinnamomi Isolates

Plant Disease ◽  
2010 ◽  
Vol 94 (1) ◽  
pp. 39-44 ◽  
Author(s):  
Jiahuai Hu ◽  
Chuanxue Hong ◽  
Erik L. Stromberg ◽  
Gary W. Moorman
Keyword(s):  
Woody Plant ◽  
Phytophthora Cinnamomi ◽  
Uv Mutagenesis ◽  
Mycelium Growth ◽  
Root Pathogen ◽  
Highly Sensitive ◽  
Plant Nursery ◽  
Mycelial Plug

Phytophthora cinnamomi is a destructive root pathogen of numerous woody plant species in the ornamental plant nursery. Sixty-five isolates of P. cinnamomi were evaluated for mefenoxam sensitivity on 20% clarified V8 agar amended with mefenoxam at 0 or 100 μg/ml. In the presence of mefenoxam at 100 μg/ml, eight isolates were intermediately sensitive, with mycelium growth ranging between 11 and 18% of the nonamended control, and 57 isolates were highly sensitive, with little or no mycelium growth. Five intermediately sensitive and five sensitive isolates were chosen to characterize their responses to mefenoxam at 0, 0.1, 1, 10, and 100 μg/ml. For intermediately sensitive isolates, the mefenoxam concentration causing 50% inhibition of mycelium growth (EC50 values) ranged between 0.03 and 0.08 μg/ml; EC50 values for sensitive isolates varied from 0.01 to 0.02 μg/ml. Five intermediately sensitive and seven sensitive isolates were selected further to assess in vivo sensitivity to mefenoxam using Lupinus angustifolius ‘Russell Hybrids’. Lupine seedlings were treated with distilled water or mefenoxam at label rate (Subdue MAXX, 1 fl. oz. of product per 100 gal.) and then, 2 days later, inoculated with a 5-mm-diameter mycelial plug of P. cinnamomi on each cotyledon. Mefenoxam-treated plants averaged more than 96% less disease than water-treated plants. Mefenoxam provided adequate protection of lupines from infection by all 12 isolates regardless of their in vitro levels of sensitivity to mefenoxam. The ability to develop mefenoxam resistance was assessed in P. cinnamomi isolates with different mefenoxam sensitivity by UV mutagenesis and adapting mycelium to increasing concentrations of mefenoxam. Both UV mutagenesis and mycelium adaptation generated isolates with reduced sensitivity to mefenoxam. These isolates, however, did not grow as quickly as their corresponding parent. This study suggests that P. cinnamomi populations from ornamental nurseries in Virginia are sensitive to mefenoxam.

scholarly journals New Oomycota Fungicides With Activity Against Phytophthora cinnamomi and Their Potential Use for Managing Avocado Root Rot in California

Plant Disease ◽  
2019 ◽  
Vol 103 (8) ◽  
pp. 2024-2032 ◽  
Author(s):  
Rodger J. Belisle ◽  
Wei Hao ◽  
Brandon McKee ◽  
Mary Lu Arpaia ◽  
Patricia Manosalva ◽  
...  
Keyword(s):  
Root Rot ◽  
Phytophthora Cinnamomi ◽  
Dry Weight ◽  
The United States ◽  
Baseline Sensitivity ◽  
Phytophthora Root Rot ◽  
Mean Values ◽  
Potassium Phosphite ◽  
Pathogen Populations

Phytophthora root rot (PRR), caused by Phytophthora cinnamomi, is the most destructive disease of avocado worldwide. In the United States, mefenoxam and phosphonate products are currently the only registered fungicides for managing avocado PRR. Four new Oomycota-specific and two registered fungicides, all with different modes of action, were evaluated. Seventy-one isolates of P. cinnamomi from avocado in California, most of them collected between 2009 to 2017, were tested for their in vitro sensitivity to the six fungicides. Baseline sensitivity ranges and mean values (in parentheses) of effective concentrations to inhibit mycelial growth by 50% (EC50) for the new fungicides ethaboxam, fluopicolide, mandipropamid, and oxathiapiprolin were 0.017 to 0.069 μg/ml (0.035), 0.046 to 0.330 μg/ml (0.133), 0.003 to 0.011 μg/ml (0.005), and 0.0002 to 0.0007 μg/ml (0.0004), respectively. In comparison, the EC50 value range (mean) was 0.023 to 0.138 μg/ml (0.061) for mefenoxam and 12.9 to 361.2 μg/ml (81.5) for potassium phosphite. Greenhouse soil inoculation trials with 8-month-old Zutano seedlings and 10-month-old Dusa and PS.54 clonal rootstocks were conducted to assess the efficacy of these fungicides for managing PRR. Mefenoxam and potassium phosphite were effective treatments; however, oxathiapiprolin, fluopicolide, and mandipropamid were more effective. Ethaboxam was effective in reducing PRR on the rootstocks evaluated. Oxathiapiprolin reduced PRR incidence and pathogen population size in the soil by >90%, and plant shoot growth and root dry weight were significantly increased compared with the control; thus, oxathiapiprolin was one of the best treatments overall. The high activity and performance of these new fungicides supports their registrations on avocado for use in rotation and mixture programs, including with previously registered compounds, to reduce the risk of development and spread of resistance in pathogen populations.

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