346 research outputs found
Control of cucumber damping-off caused by Pythium ultimum, with organic matter
The effectiveness of several media soil-sand-pertile (1:1:1 v/v); soil-sand-pertile-manure (1:1:1:3); soil-sand-perlite-compost (1:1:1:3); soil-sand-perlite-peat (1:1:1:3); soil-sand-perlite-straw (1:1:1:3), and sand-perlite-peat-compost-mamure-wheat straw (2:2:1:3:3:1) as suppressers of the cucumber (Cucumis sativus) damping-off causal agent, Pythium ultimum, was evaluated. The media were infested with 12 g/l of Pythium inoculum (broken corn-sand medium), fifteen days before sowing ten cucumber seeds (mezzolungo Marketer) 1 cm deep in pots containing approximately 500 ml of medium. Plants were grown at a constant temperature of 25oC simbolo 177\\ f "Symbol" \\s 12 2 with 12 hours of illumination per day. The percentage of emerged seedlings, post- and pre-emerg ent damping-off and disease severity were determined at fifteen days after planting. This procedure was repeated on the same substrates, without reinoculation, ten days after harvesting this first trial. The manure medium was the most suppressive to the disease, with percent of emergence, percent of pre-and post-emergence damping-off and disease severity values of 84.5%, 12.0%, 0% and 1.35, respectively, for the first bioassay. The replanting experiment results were 98.5%, 0%, 0% and 1,0, respectively. However, plants grown in this medium in both bioassays were shorter than ones grown in the other media. Peat medium and the mixture sand-peat-manure-compost-wheat straw medium were more conducive to the disease than wheat straw medium, resulting in higher occurrence and severity of attack by Pythium
Bacillus subtilis for the control of powdery mildew on cucumber and zucchini squash.
Application of concentrated metabolites of Bacillus subtilis - CMBS - (5,000 ug/mL) one and 24 h before or after inoculation of Sphaerotheca fuliginea (3 x 10 4 conidia/mL) reduced the number of lesions on cucumber leaves by 90-99%. The average number of lesions on control plants was 16.7 per leaf. A wettable powder product formulated with cells (10%) and metabolites (10%) of B. subtilis (WPBS), and CMBS sprayed on cucumber plants (1,000 ug/mL and 10,000 ug/mL) twice a week totally controlled powdery mildew. In the control treatment, 18 days after the first spray, the percent leaf surface covered by lesions was 99.0 and 46.7%, on the cotyledonary and expanded leaves, respectively. In the control treatment, 30 days after the first spray, the percent leaf surface with lesions was 26.1%, while leaves sprayed with CMBS presented no lesions. The fresh weight per plant was 4.3 g in the control treatment; 12.2 g, and 10.2 for plants sprayed with CMBS at the concentration of 1,000 and 10,000 ug/mL, respectively; and 9.7 g and 10.1 g for plants sprayed with WPBS 1,000 and 10,000 ug/mL, respectively. For zucchini squash, CMBS (5,000 ug/mL) sprayed every 2,4, and 6 days showed reductions in lesioned leaf surface of 100.0,98.3, and 94,7%, respectively
Plant extracts as biocontrol agents against Aspergillus carbonarius growth and ochratoxin A production in grapes
Aspergillus carbonarius (Bainier) Thom. is an important pathogen and ochratoxin A (OTA) producer in grapes that
can be controlled by adopting sustainable approaches. Here we evaluate the application of natural plant extracts
as an alternative to synthetic fungicides to reduce OTA contamination and to prevent infection of grapes by two
isolates of A. carbonarius. In a preliminary screening, natural extracts of chestnut flower, cistus, eucalyptus,
fennel, and orange peel were evaluated for their antifungal and anti-mycotoxigenic efficiency in a grape-based
medium at concentrations of 10 and 20 mg/mL. Cistus and orange peel extracts demonstrated the best anti-
fungal activity at both concentrations. Although the eucalyptus extract demonstrated no significant effect on
Aspergillus vegetative growth, it significantly reduced OTA by up to 85.75 % at 10 mg/mL compared to the
control. Chestnut flower, cistus, eucalyptus, and orange peel extracts were then tested at the lowest concen-
tration (10 mg/mL) for their antifungal activity in artificially inoculated grape berries. The cistus and orange peel
extracts demonstrated the greatest antifungal activity and significantly reduced mold symptoms in grapes.
Moreover, all tested natural extracts were able to reduce OTA content in grape berries (17.7 ± 8.3 % - 82.3 ±
3.85 % inhibition), although not always significantly. Eucalyptus extract was particularly efficient, inhibiting
OTA production by both strains of A. carbonarius by up to >80 % with no effects on fungal growth. The use of
natural eucalyptus extract represents a feasible strategy to reduce OTA formation without disrupting fungal
growth, apparently maintaining the natural microbial balance, while cistus and orange peel extracts appear
promising as inhibitors of A. carbonarius mycelial growth. Our findings suggest that plant extracts may be useful
sources of bioactive chemicals for preventing A. carbonarius contamination and OTA production. Nonetheless, it
will be necessary to evaluate their effect on the organoleptic properties of the grapes.This work was supported by the Foundation for Science and Tech-
nology (FCT, Portugal) #1 under Grant from national funds FCT/MCTES
(PIDDAC) to CIMO [number UIDB/00690/2020 and UIDP/00690/
2020] and SusTEC [number LA/P/0007/2020]; the European Regional
Development Fund (ERDF) through the Competitiveness and Interna-
tionalization Operational Program (CIOP) #2 under Grant dedicated to
the project “PreVineGrape - Development of a biofungicide to combat
grapevine diseases [number POCI-01-0247-FEDER-049695].info:eu-repo/semantics/publishedVersio
Controle, com matéria orgânica, do tombamento do pepino, causado por Pythium ultimum trow.
Foi avaliada a efetividade dos substratos: solo-areia-perlita (1:1:1.v/v); solo-areia-perlita-esterco (1:1:1:3); solo-areia-perlita-composto (1:1:1:3); solo-areia-perlita-turfa (1:1:1:3); solo-areia-perlita-palha de trigo (1:1:1:3); e areia-perlita-turfa-composto-esterco-palha de trigo (2:2:1:3:3:1), em suprimir o tombamento de pepino (Cucumis sativus L.) causado por Pythium ultimum Trow. Esses substratos foram infestados com 12 g/L de inoculo de Pythium (quirera-areia-agua), quinze dias antes da semeadura de dez sementes de pepino (Mezzolungo Marketer) a 1 cm de profundidade, em vasos contendo aproximadamente 500 ml de substrato. As plantulas se desenvolveram em camara de crescimento, com temperatura de 25oC +- 2 e doze horas de luz. A porcentagem de emergencia, o tombamento de pre e de pos-emergencia e a severidade da doenca foram determinadas quinze dias apos a semeadura. Uma segunda semeadura, dez dias apos a retirada das plantas, foi realizada nos mesmos substratos. O substrato enriquecido com esterco foi o que apresentou maior supressividade a doenca, com valores de porcentagem de emergencia, tombamento de pre e de pos-emergencia, e de severidade de 84,5%, 12,0%, 0% e 1,35, respectivamente, no primeiro cultivo. No replantio, os resultados foram 98,5%, 0,0%, 0,0% e 1,0, respectivamente. O substrato com turfa e o com mistura das materias organicas foram mais conducentes do que o que continha palha de trigo
New perspective for an old drug: Can naloxone be considered an antioxidant agent?
Background: Experimental evidence indicates that Naloxone (NLX) holds antioxidant properties. The present study aims at verifying the hypothesis that NLX could prevent oxidative stress induced by hydrogen peroxide (H2O2) in PC12 cells.Methods: To investigate the antioxidant effect of NLX, initially, we performed electrochemical experiments by means of platinum-based sensors in a cell-free system. Subsequently, NLX was tested in PC12 cells on H2O2induced overproduction of intracellular levels of reactive-oxygen-species (ROS), apoptosis, modification of cells' cycle distribution and damage of cells' plasma membrane.Results: This study reveals that NLX counteracts intracellular ROS production, reduces H2O2-induced apoptosis levels, and prevents the oxidative damage-dependent increases of the percentage of cells in G2/M phase. Likewise, NLX protects PC12 cells from H2O2- induced oxidative damage, by preventing the lactate dehydrogenase (LDH) release. Moreover, electrochemical experiments confirmed the antioxidant properties of NLX.Conclusion: Overall, these findings provide a starting point for studying further the protective effects of NLX on oxidative stress
Simultaneous wireless and high-resolution detection of nucleus accumbens shell ethanol concentrations and free motion of rats upon voluntary ethanol intake
Highly sensitive detection of ethanol concentrations in discrete brain regions of rats voluntarily accessing ethanol, with high temporal resolution, would represent a source of greatly desirable data in studies devoted to understanding the kinetics of the neurobiological basis of ethanol's ability to impact behavior. In the present study, we present a series of experiments aiming to validate and apply an original high-tech implantable device, consisting of the coupling, for the first time, of an amperometric biosensor for brain ethanol detection, with a sensor for detecting the microvibrations of the animal. This device allows the real-time comparison between the ethanol intake, its cerebral concentrations, and their effect on the motion when the animal is in the condition of voluntary drinking. To this end, we assessed in vitro the efficiency of three different biosensor designs loading diverse alcohol oxidase enzymes (AOx) obtained from three different AOx-donor strains: Hansenula polymorpha, Candida boidinii, and Pichia pastoris. In vitro data disclosed that the devices loading H. polymorpha and C. boidinii were similarly efficient (respectively, linear region slope [LRS]: 1.98 ± 0.07 and 1.38 ± 0.04 nA/mM) but significantly less than the P. pastoris-loaded one (LRS: 7.57 ± 0.12 nA/mM). The in vivo results indicate that this last biosensor design detected the rise of ethanol in the nucleus accumbens shell (AcbSh) after 15 minutes of voluntary 10% ethanol solution intake. At the same time, the microvibration sensor detected a significant increase in the rat's motion signal. Notably, both the biosensor and microvibration sensor described similar and parallel time-dependent U-shaped curves, thus providing a highly sensitive and time-locked high-resolution detection of the neurochemical and behavioral kinetics upon voluntary ethanol intake. The results overall indicate that such a dual telemetry unit represents a powerful device which, implanted in different brain areas, may boost further investigations on the neurobiological mechanisms that underlie ethanol-induced motor activity and reward
The transition of people’s preferences for the intervention of the government in the economy of re-unified Germany
Covering the first fifteen years immediately after German re- unification, this paper analyzes the people’s support to the transition. The focus is on individuals’ preferences for the intervention of the government in the economy and on the opinion about competition per se. Eastern German data are compared with Western German data. Using suitable data that allow for interpersonal comparisons, the paper shows that Eastern Germans have always preferred an intervention of the public hand in the economy deeper than Western Germans; these different positions have hardly converged during the examined period of time. However there are no significant differences with respect to how Germans perceive competition per se: it is considered as a good by the people living in both parts of the country.info:eu-repo/semantics/publishedVersio
Real-Time Monitoring of Brain Tissue Oxygen Using a Miniaturized Biotelemetric Device Implanted in Freely Moving Rats
A miniaturized biotelemetric device for the amperometric detection of brain tissue oxygen is presented. The new system, derived from a previous design, has been coupled with a carbon microsensor for the real-time detection of dissolved O(2) in the striatum of freely moving rats. The implantable device consists of a single-supply sensor driver, a current-to-voltage converter, a microcontroller, and a miniaturized data transmitter. The oxygen current is converted to a digital value by means of an analog-to-digital converter integrated in a peripheral interface controller (PIC). The digital data is sent to a personal computer using a six-byte packet protocol by means of a miniaturized 434 MHz amplitude modulation (AM) transmitter. The receiver unit is connected to a personal computer (PC) via a universal serial bus. Custom developed software allows the PC to store and plot received data. The electronics were calibrated and tested in vitro under different experimental conditions and exhibited high stability, low power consumption, and good linear response in the nanoampere current range. The in vivo results confirmed previously published observations on oxygen dynamics in the striatum of freely moving rats. The system serves as a rapid and reliable model for studying the effects of different drugs on brain oxygen and brain blood flow and it is suited to work with direct-reduction sensors or O(2)-consuming biosensors
LRRK2 affects vesicle trafficking, neurotransmitter extracellular level and membrane receptor localization
The leucine-rich repeat kinase 2 (LRRK2) gene was found to play a role in the pathogenesis of both familial and sporadic Parkinson's disease (PD). LRRK2 encodes a large multi-domain protein that is expressed in different tissues. To date, the physiological and pathological functions of LRRK2 are not clearly defined. In this study we have explored the role of LRRK2 in controlling vesicle trafficking in different cellular or animal models and using various readouts. In neuronal cells, the presence of LRRK2(G2019S) pathological mutant determines increased extracellular dopamine levels either under basal conditions or upon nicotine stimulation. Moreover, mutant LRRK2 affects the levels of dopamine receptor D1 on the membrane surface in neuronal cells or animal models. Ultrastructural analysis of PC12-derived cells expressing mutant LRRK2(G2019S) shows an altered intracellular vesicle distribution. Taken together, our results point to the key role of LRRK2 to control vesicle trafficking in neuronal cells
Pest categorisation of Xanthomonas citri pv. viticola
The EFSA Plant Health Panel performed a pest categorisation of Xanthomonas citri pv. viticola (Nayudu) Dye, a Gram-negative bacterium belonging to the Xanthomonadaceae family. The pathogen is a well-defined taxonomic unit and is the causal agent of the leaf spot and bacterial canker of Vitis vinifera. This bacterium is present in India and Brazil, where it affects table grape cultivation; the same pathogen is able to cause a disease on Azadirachta indica and on some weed species. Reports indicate that the bacterium is present in Thailand as well. The pathogen has never been reported from the EU territory and it is not included in EU Commission Implementing Regulation 2019/2072. The pathogen can be detected on its host plants using direct isolation, serological or PCR-based methods. Its identification is achieved using biochemical and nutritional assays, together with a multilocus sequence analysis based on seven housekeeping genes. The main pathway for the entry of the pathogen into the EU territory is plant propagation material. In the EU, there is large availability of host plants, with grapevine being one of the most important crops in Europe and more specifically in its Mediterranean areas. Since X. citri pv. viticola is only reported in tropical and subtropical areas (BSh and Aw climatic zones according to the Köppen–Geiger classification), there is uncertainty whether the climatic conditions in the EU territory are suitable for its establishment. Nevertheless, due to the great importance of grapevine for the EU agriculture, any disease outbreak may have a high-economic impact. Phytosanitary measures are available to prevent the introduction of the pathogen into the EU. X. citri pv. viticola satisfies the criteria that are within the remit of EFSA to assess for this species to be regarded as a potential Union quarantine pest
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