scholarly journals Inhibitory effect of thymol on pheromone-mediated attraction in two pest moth species

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sergio López ◽  
Aroa Domínguez ◽  
Ángel Guerrero ◽  
Carmen Quero
Keyword(s):  
Inhibitory Effect ◽  
Major Constituent ◽  
Mediated Communication ◽  
Plant Essential Oils ◽  
Thyme Oil ◽  
Antennal Response ◽  
Environmentally Safe ◽  
Major Pest ◽  
High Doses ◽  
Lepidoptera Noctuidae

AbstractPlant essential oils are considered as important bio-sources for the development of natural and environmentally safe pest control tools due to their multiple modes of action on insects. In this paper we have evaluated the activity of commercially available thyme oil and its constituents thymol, carvacrol, and p-cymene, as potential disruptants of the pheromone-mediated communication in the major pest moths Spodoptera littoralis Boisduval (Lepidoptera: Noctuidae), and Grapholita molesta (Busck) (Lepidoptera: Tortricidae). In electroantennographic assays, the antennal response of males to thyme oil, thymol, and carvacrol was altered at high doses (103–104 µg), shifting the signal waveform into a biphasic negative–positive potential that caused a decay in the response. In wind tunnel assays, pheromone-mediated attraction of males of both species was interrupted in presence of thyme oil. Further trials demonstrated that thymol alone reduced the number of G. molesta and S. littoralis males landing on the pheromone source. This effect did not differ from that of thyme oil, although the latter provoked a significant reduction on downwind behavior steps in S. littoralis. Overall, our findings provide a preliminary basis for delving into the effect of thyme oil, and especially of its major constituent thymol, as potential mating disruptants of both species.

scholarly journals In vitro evaluation of eight plant essential oils for controlling Colletotrichum, Botryosphaeria, Fusarium and Phytophthora fruit rots of avocado, mango and papaya

2018 ◽  
Vol 54 (No. 3) ◽  
pp. 153-162 ◽  
Author(s):  
Sarkhosh Ali ◽  
Schaffer Bruce ◽  
Vargas Ana I ◽  
Palmateer Aaron J ◽  
Lopez Patricia ◽  
...  
Keyword(s):  
Essential Oils ◽  
Plant Species ◽  
Major Constituent ◽  
Mycelium Growth ◽  
In Vitro Evaluation ◽  
Tea Tree ◽  
Plant Essential Oils ◽  
Thyme Oil ◽  
Application Rates

In vitro efficacy of the essential oils extracted from eight plant species was tested at application rates of 100, 250, 500, 1000, or 2000 µl/l for controlling fruit rots. Results showed a 100% reduction of mycelium growth of Colletotrichum, Fusarium, Phytophthora, Botryosphaeria after applying thyme or savory oils at all concentrations tested. Mint and cinnamon oils inhibited mycelium growth of the five isolates at application rates of either 1000 or 2000 µl/l. Tea tree, lavender, myrtle, and eucalyptus oils were slightly effective at controlling mycelium growth of each fungus species tested. Savory oil with major constituent of carvacrol 71.2% and thyme oil with major constituent of thymol 73.3% showed the greatest potential of the essential oils tested for use as natural fungicides.

Opposite Effect of Lysine on Platelet Aggregation Induced by Arachidonate and by Other Aggregants

1982 ◽  
Vol 48 (01) ◽  
pp. 078-083 ◽  
Author(s):  
C Ts'ao ◽  
S J Hart ◽  
D V Krajewski ◽  
P G Sorensen
Keyword(s):  
Platelet Aggregation ◽  
Secondary Phase ◽  
Aminocaproic Acid ◽  
Adenosine Diphosphate ◽  
Inhibitory Effect ◽  
Human Platelets ◽  
Primary Phase ◽  
High Doses ◽  
The Many ◽  
Induced Aggregation

SummaryEarlier, we found that ε-aminocaproic acid (EACA) inhibited human platelet aggregation induced by adenosine diphosphate (ADP) and collagen, but not aggregation by arachidonic acid (AA). Since EACA is structurally similar to lysine, yet these two agents exhibit vast difference in their antifibrinolytic activities, we chose to study the effect of lysine on platelet aggregation. We used L-lysine-HCl in these studies because of its high solubility in aqueous solutions while causing no change in pH when added to human plasma. With lysine, we repeatedly found inhibition of ADP-, collagen- and ristocetin-induced aggregation, but potentiation of AA-induced aggregation. Both the inhibitory and potentiation effects were dose-dependent. Low doses of lysine inhibited the secondary phase of aggregation; high doses of it also inhibited the primary phase of aggregation. Potentiation of AA-induced aggregation was accompanied by increased release of serotonin and formation of malondialdehyde. These effects were not confined to human platelets; rat platelets were similarly affected. Platelets, exposed to lysine and then washed and resuspended in an artificial medium not containing lysine, remained hypersensitive to AA, but no longer showed decreased aggregation by collagen. Comparing the effects of lysine with equimolar concentrations of sucrose, EACA, and α-amino-n-butyric acid, we attribute the potent inhibitory effect of lysine to either the excess positive charge or H+ and C1− ions. The -NH2 group on the α-carbon on lysine appears to be the determining factor for the potentiation effect; the effect seems to be exerted on the cyclooxygenase level of AA metabolism. Lysine and other chemicals with platelet-affecting properties similar to lysine may be used as a tool for the study of the many aspects of a platelet aggregation reaction.

scholarly journals Biochemical characterisation of α-glucosidase and β-glucosidase in the alimentary canal of larval Leptinotarsa decemlineata SAY, 1824 (Coleoptera: Chrysomelidae)

2014 ◽  
Vol 83 (4) ◽  
pp. 281-294 ◽  
Author(s):  
Majid Kazzazi ◽  
Fahimeh Dehghanikhah ◽  
Hossein Madadi ◽  
Vahid Hossseininaveh
Keyword(s):  
Incubation Time ◽  
Leptinotarsa Decemlineata ◽  
Digestive Enzymes ◽  
Specific Activity ◽  
Inhibitory Effect ◽  
Maximum Activity ◽  
Pest Population ◽  
Biochemical Characterisation ◽  
Leptinotarsa Decemlineata Say ◽  
Environmentally Safe

ABSTRACT Host plant resistance is an environmentally safe method used for reducing a pest population. Basically, when developing resistant cultivars one needs to study the biochemical characteristics of the digestive enzymes in the insect’s midgut. In this study, the activities of α- and β-glucosidase were determined from Leptinotarsa decemlineata midgut using p-nitrophenyl-α-Dglucopyranoside and p-nitrophenyl-β-D-glucopyranoside as substrates respectively. The results showed that the specific activity of α- and β-glucosidase from 4th instar larvae midguts of L. decemlineata were 5.14 and 5.48 Umg-1 protein respectively. The activity of α-glucosidase was optimal at pH 4, whereas the maximum activity of β-glucosidase in the midgut of L. decemlineata occurred at pH 4-5.5. Both enzymes were stable at pH 3-8 over an incubation time of 8 hours. The respective activities of α- and β-glucosidase were at their highest at 45 °C and 50 °C, but they were not stable at 50 °C during an incubation time of 8 days. Furthermore, our data showed that MgCl2, Tris and urea have a moderate but SDS a severe inhibitory effect on enzyme activity. Biochemical characterisation revealed one and three bands of α- and β-glucosidase activities in the midgut of L. decemlineata respectively.

Effect of Plant Essential Oils and Their Major Constituents on Cypermethrin Tolerance Associated Detoxification Enzyme Activities in Spodoptera litura (Lepidoptera: Noctuidae)

2019 ◽  
Vol 112 (5) ◽  
pp. 2167-2176 ◽  
Author(s):  
Torranis Ruttanaphan ◽  
Wanchai Pluempanupat ◽  
Chutikan Aungsirisawat ◽  
Polnarong Boonyarit ◽  
Gaelle Le Goff ◽  
...  
Keyword(s):  
Essential Oil ◽  
Synergistic Effect ◽  
Essential Oils ◽  
Spodoptera Litura ◽  
Cytochromes P450 ◽  
Detoxification Enzymes ◽  
Plant Essential Oils ◽  
Activity Measurements ◽  
Lepidoptera Noctuidae ◽  
Essential Oil Compounds

Abstract Essential oils are well known to act as biopesticides. This research evaluated the acute toxicity and synergistic effect of essential oil compounds in combination with cypermethrin against Spodoptera litura Fabricius (Lepidoptera: Noctuidae). The effects of distillation extracts of essential oils from Alpinia galanga Zingiberaceae (Zingiberales) rhizomes and Ocimum basilicum Lamiaceae (Lamiales) leaves; one of their primary essential oil compounds 1,8-cineole; and linalool were studied on second-instar S. litura by topical application under laboratory conditions. The results showed that A. galanga had the highest control efficiency, whereas1,8-cineole provided a moderate efficacy. The mixtures of linalool, 1,8-cineole, O. basilicum, or A. galanga with cypermethrin were synergistic on mortality. Activity measurements of the main detoxification enzymes show that linalool and 1,8-cineole inhibit the activity of cytochromes P450 and carboxylesterases, which could explain their synergistic effect. Based on our results, the use of these mixtures represents an ideal eco-friendly approach, helping to manage cypermethrin resistance of S. litura.

The inhibitory effect of plant essential oils on foodborne pathogenic bacteria in food

2018 ◽  
Vol 59 (20) ◽  
pp. 3281-3292 ◽  
Author(s):  
Jian Ju ◽  
Yunfei Xie ◽  
Yahui Guo ◽  
Yuliang Cheng ◽  
He Qian ◽  
...  
Keyword(s):  
Essential Oils ◽  
Pathogenic Bacteria ◽  
Inhibitory Effect ◽  
Plant Essential Oils ◽  
Foodborne Pathogenic Bacteria

scholarly journals Comparative Evaluation of the Inhibitory Effect of Some Essential Oils with Antibiotics against Pseudomonas aeruginosa

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Lobna El-Hosseiny ◽  
Moustafa El-Shenawy ◽  
Medhat Haroun ◽  
Fadhil Abdullah
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antibacterial Activity ◽  
Essential Oil ◽  
Essential Oils ◽  
Inhibitory Effect ◽  
Chemical Components ◽  
Spectroscopy Analysis ◽  
Thyme Oil ◽  
Bioactive Agents ◽  
Gas Chromatography Mass Spectroscopy

Gas chromatography/mass spectroscopy analysis was performed to identify the chemical components of three extracted essential oils including thyme, marjoram, and sage. The antibacterial activity of the extracted essential oils against Pseudomonas aeruginosa (ATCC 9027) was investigated using disc diffusion assay, either alone or in combination with standard antibiotics (piperacillin, cefepime, meropenem, gentamicin, and norfloxacin). Results showed that the studied oils exhibited a variety of activities against the tested bacterium. Thyme oil was the most active followed by marjoram oil, whereas sage displayed no activity towards the tested organism. Thyme oil enhanced the antibacterial activity of cell wall targeting antibiotics (piperacillin, cefepime, and meropenem) by more than twofold. Marjoram oil potentiated the activity of all the tested antibiotics except norfloxacin. Sage, despite its inactivity against pseudomonas, synergistically enhanced the activity of piperacillin, meropenem, and gentamicin. Thyme essential oil, containing thymol as a major component (33.6%), exhibited higher activity alone or in combination with antibiotics than marjoram which contained alcoholic terpenes or sage essential oil that contained 1,8-cineole as its major component (29%). The investigated oils, as natural bioactive agents, may be used to enhance the activity of antibiotics towards pseudomonas.

Positive association between resistance to Bacillus thuringiensis and overwintering survival of cabbage loopers, Trichoplusia ni (Lepidoptera: Noctuidae)

2008 ◽  
Vol 98 (3) ◽  
pp. 317-322 ◽  
Author(s):  
V. Caron ◽  
J.H. Myers
Keyword(s):  
Bacillus Thuringiensis ◽  
Trichoplusia Ni ◽  
Positive Association ◽  
Pest Species ◽  
Development Of Resistance ◽  
Trade Offs ◽  
Major Pest ◽  
Selection For ◽  
Overwintering Survival ◽  
Lepidoptera Noctuidae

AbstractDevelopment of resistance to insecticides has generally been associated with fitness costs that may be magnified under challenging conditions. Lepidopterans which are resistant to the biopesticide Bacillus thuringiensis subsp. kurstaki (Btk) have been shown to have reduced fitness, such as lower survival when subjected to overwintering stress. Recently, resistance to Btk has been found in some populations of Trichoplusia ni Hübner in greenhouses in British Columbia. This situation provides an opportunity to investigate potential trade-offs between overwintering survival and insecticide resistance in a major pest species. Here, we assess the survival and eventual fecundity of Btk resistant and susceptible T. ni pupae exposed to cool temperatures. Contrary to our expectations, resistant T. ni had higher overwintering survival than susceptible individuals. This is the first account of a potential advantage associated with Btk resistance. Resistant and susceptible moths had reduced fecundity and smaller progeny after cold exposure compared to controls, and this may counteract the survival advantage. Nevertheless, it seems unlikely that this is sufficient to select out the resistant phenotype in the presence of strong selection for resistance and in the absence of immigration of susceptible moths. The appearance of resistance without evidence of a trade-off in overwintering survival presents a major challenge to management in production greenhouses.

Insecticidal toxicity of thirteen commercial plant essential oils against Spodoptera exigua (Lepidoptera: Noctuidae)

2018 ◽  
Vol 46 (2) ◽  
pp. 233-245 ◽  
Author(s):  
Ana Murcia-Meseguer ◽  
Thiago J. S. Alves ◽  
Flor Budia ◽  
Antonio Ortiz ◽  
Pilar Medina
Keyword(s):  
Essential Oils ◽  
Spodoptera Exigua ◽  
Plant Essential Oils ◽  
Commercial Plant ◽  
Insecticidal Toxicity ◽  
Lepidoptera Noctuidae

Influence of purinoceptors' agonists and antagonists on opossum internal anal sphincter

1988 ◽  
Vol 255 (3) ◽  
pp. G389-G394 ◽  
Author(s):  
S. Rattan ◽  
R. Shah
Keyword(s):  
Anal Sphincter ◽  
Internal Anal Sphincter ◽  
Inhibitory Effect ◽  
Inhibitory Response ◽  
Rectal Balloon ◽  
Balloon Distension ◽  
Before And After ◽  
High Doses ◽  
Alpha Chloralose ◽  
Dose Dependent

Studies were performed in alpha-chloralose-anesthetized and pancuronium-treated opossums. Resting internal anal sphincter pressures (IASP) were monitored using low-compliant continuously perfused catheters. P1 and P2 purinoceptor agonists, adenosine and ATP, respectively, administered close intra-arterially, caused dose-dependent decreases in the IASP. The inhibitory effect of these agonists on the IASP was tetrodotoxin resistant. Rectal balloon distension (RD) (which mimics the rectoanal inhibitory reflex) caused volume-dependent IAS relaxation. Electrical stimulation of the sacral nerve (SNS) also produced frequency-dependent decreases in IASP. The inhibitory response to adenosine (P1 purinoceptor agonist), ATP (P2 purinoceptor agonist), RD, and SNS on the internal anal sphincter (IAS) was examined before and after 8-phenyltheophylline (P1 purinoceptor antagonist) and alpha,beta-methylene ATP (P2 purinoceptor antagonist that irreversibly binds and desensitizes P2 purinoceptor). P1 and P2 purinoceptor antagonists produced selective antagonism of the inhibitory responses on the IAS of their respective agonists only. Furthermore, high doses of adenosine and ATP produced desensitization and block of their own actions only. The purinoceptors' antagonists, and the desensitization of purinoceptors by high doses of adenosine and ATP, failed to modify the fall in IASP in response to RD or SNS. From these studies we conclude that distinct inhibitory P1 and P2 purinoceptors are present on the IAS smooth muscle. However, these inhibitory purinoceptors may not be responsible for the rectoanal reflex-mediated IAS relaxation.

Sign in / Sign up

Export Citation Format

Share Document