Impact of Coated Zinc Oxide Nanoparticles on Photosystem II of Tomato Plants

Zinc oxide nanoparticles (ZnO NPs) have emerged as a prominent tool in agriculture. Since photosynthetic function is a significant measurement of phytotoxicity and an assessment tool prior to large-scale agricultural applications, the impact of engineered irregular-shaped ZnO NPs coated with oleylamine (ZnO@OAm NPs) were tested. The ZnO@OAm NPs (crystalline size 19 nm) were solvothermally prepared in the sole presence of oleylamine (OAm) and evaluated on tomato (Lycopersicon esculentum Mill.) photosystem II (PSII) photochemistry. Foliar-sprayed 15 mg L−1 ZnO@OAm NPs on tomato leaflets increased chlorophyll content that initiated a higher amount of light energy capture, which resulted in about a 20% increased electron transport rate (ETR) and a quantum yield of PSII photochemistry (ΦPSII) at the growth light (GL, 600 μmol photons m−2 s−1). However, the ZnO@OAm NPs caused a malfunction in the oxygen-evolving complex (OEC) of PSII, which resulted in photoinhibition and increased ROS accumulation. The ROS accumulation was due to the decreased photoprotective mechanism of non-photochemical quenching (NPQ) and to the donor-side photoinhibition. Despite ROS accumulation, ZnO@OAm NPs decreased the excess excitation energy of the PSII, indicating improved PSII efficiency. Therefore, synthesized ZnO@OAm NPs can potentially be used as photosynthetic biostimulants for enhancing crop yields after being tested on other plant species

Nanocapsules of ZnO Nanorods and Geraniol as a Novel Mean for the Effective Control of Botrytis cinerea in Tomato and Cucumber Plants

Inorganic-based nanoparticle formulations of bioactive compounds are a promising nanoscale application that allow agrochemicals to be entrapped and/or encapsulated, enabling gradual and targeted delivery of their active ingredients. In this context, hydrophobic ZnO@OAm nanorods (NRs) were firstly synthesized and characterized via physicochemical techniques and then encapsulated within the biodegradable and biocompatible sodium dodecyl sulfate (SDS), either separately (ZnO NCs) or in combination with geraniol in the effective ratios of 1:1 (ZnOGer1 NCs), 1:2 (ZnOGer2 NCs), and 1:3 (ZnOGer2 NCs), respectively. The mean hydrodynamic size, polydispersity index (PDI), and ζ-potential of the nanocapsules were determined at different pH values. The efficiency of encapsulation (EE, %) and loading capacity (LC, %) of NCs were also determined. Pharmacokinetics of ZnOGer1 NCs and ZnOGer2 NCs showed a sustainable release profile of geraniol over 96 h and a higher stability at 25 ± 0.5 °C rather than at 35 ± 0.5 °C. ZnOGer1 NCs, ZnOGer2 NCs and ZnO NCs were evaluated in vitro against B. cinerea, and EC50 values were calculated at 176 μg/mL, 150 μg/mL, and > 500 μg/mL, respectively. Subsequently, ZnOGer1 NCs and ZnOGer2 NCs were tested by foliar application on B. cinerea-inoculated tomato and cucumber plants, showing a significant reduction of disease severity. The foliar application of both NCs resulted in more effective inhibition of the pathogen in the infected cucumber plants as compared to the treatment with the chemical fungicide Luna Sensation SC. In contrast, tomato plants treated with ZnOGer2 NCs demonstrated a better inhibition of the disease as compared to the treatment with ZnOGer1 NCs and Luna. None of the treatments caused phytotoxic effects. These results support the potential for the use of the specific NCs as plant protection agents against B. cinerea in agriculture as an effective alternative to synthetic fungicides

Functional nanostructures based on zinc oxide and calcium oxide for agrochemical applications

The use of conventional agrochemical products is a major global issue, as it has consequences for the food security of the population and for the balance and quality of the natural environment. Advances in nanomaterials provide prospects for their development in the agricultural sector in order to overcome the problems. The scope of this thesis is the synthesis and characterization of coated primary nanoparticles based on calcium, zinc and copper and their development into secondary nanostructures, as well as their evaluation as nanoagrochemicals. Specifically, seven primary and differently coated ZnO NPs were prepared and physicochemically characterized in terms of sizes (15-27 nm), organic coating (oleylamine, octadecylamine, polyethylene glycol 8000) and shape (irregular, rods, flowers) as a result of different synthetic approaches and nanoparticle growth mode. Also, oleylamine-coated Ca(OH)2 NPs and pegylated Cu, CuZn and Cu-doped ZnO nanoparticles were isolated. The syntheses were carried out by solvothermal and microwave-assisted method. Based on the primary nanoparticles, secondary nanostructures were prepared: (i) nanocapsules of Ca(OH)2 or ZnO with geraniol, a natural active ingredient with fungicidal activity and (ii) heteronanocomposites of Ca(OH)2@ZnO. The characterization of the primary nanoparticles, nanocapsules and heteronanocomposite structures in terms of their composition, structure, morphology and surface properties was carried out by X-ray diffraction, TEM and SEM/EDS electron microscopy, FT-IR, UV-Vis spectroscopy, thermogravimetric analysis, dynamic light scattering and X-ray photoelectron spectroscopy. The release study of the geraniol was determined using zero-order, first-order, Higuchi and Korsmeyer-Peppas models. In vitro and in planta bioassays were performed; evaluation in lettuce of primary nanoparticles to control the growth of the plant pathogenic fungi B. cinerea and S. sclerotiorum and the nematode M. javanica. Nanocapsules of Ca(OH)2 or ZnO NPs with geraniol were evaluated for their antifungal activity against B. cinerea both in vitro and in planta, cucumbers. Finally, coated ZnO NPs of different shapes (irregular and rod-shaped) and of different percentage of oleylamine coating were studied for their effect on photosystem II photochemistry of tomatoes.Η χρήση των συμβατικών αγροχημικών προϊόντων αποτελεί ένα σημαντικό παγκόσμιο ζήτημα, καθώς επιφέρει συνέπειες στην επισιτιστική ασφάλεια του πληθυσμού αλλά και στην ισορροπία και ποιότητα του φυσικού περιβάλλοντος. Η πρόοδος των νανοϋλικών παρέχει προοπτικές ανάπτυξής τους στον αγροτικό τομέα προκειμένου να ξεπεραστούν τα προβλήματα. Το αντικείμενο της παρούσας διατριβής αφορά τη σύνθεση και το χαρακτηρισμό επικαλυμμένων πρωτογενών νανοσωματιδίων με βάση το ασβέστιο, τον ψευδάργυρο και το χαλκό και την ανάπτυξη αυτών σε προηγμένες δευτερογενείς αρχιτεκτονικές, καθώς και την αξιολόγηση τους μέσω βιοδοκιμών ως νανοαγροχημικά. Συγκεκριμένα, σολβοθερμικά ή/και με τη μέσω υποβοηθούμενης από μικροκυματική ακτινοβολία μέθοδο παρασκευάστηκαν και χαρακτηρίστηκαν επτά διαφορετικά (πρωτογενή) ZnO NPs από την άποψη μεγεθών (15 ̶ 27 nm), οργανικής επικάλυψης (ολεϋλαμίνη, οκταδεκυλαμίνη, πολυαιθυλενογλυκόλη 8000) και σχήματος (ακανόνιστα, ράβδοι, λουλούδια) ως αποτέλεσμα διαφορετικών συνθετικών προσεγγίσεων και του τρόπου ανάπτυξης των νανοσωματιδίων. Επιπροσθέτως, απομονώθηκαν επικαλυμμένα με ολεϋλαμίνη νανοσωματίδια Ca(OH)2 και επικαλυμμένα με γλυκόλες νανοσωματίδια Cu, CuZn και Cu-doped ZnO. Με βάση τα πρωτογενή νανοσωματίδια παρασκευάστηκαν δευτερογενείς αρχιτεκτονικές νανοδομές (i) νανοκάψουλες με βάση Ca(OH)2 ή ZnO NPs σε συνδυασμό με τη γερανιόλη, μία φυσική ουσία με μυκητοκτόνο δράση που περιέχεται σε αιθέρια έλαια και (ii) ετερονανοσύνθετες δομές Ca(OH)2@ZnO. Ο φυσικοχημικός χαρακτηρισμός των πρωτογενών νανοσωματιδίων, των νανοκαψουλών και ετερονανοσύνθετων δομών ως προς τη σύσταση, τη δομή, τη μορφολογία και τις επιφανειακές τους ιδιότητες έγινε με περίθλαση ακτίνων Χ, ηλεκτρονικές μικροσκοπίες ΤΕΜ και SEM/EDS, φασματοσκοπίες FT-IR, UV-Vis, θερμοβαρυμετρική ανάλυση, δυναμική σκέδαση φωτός και φωτοηλεκτρονίων Ακτίνων-Χ. Η μελέτη αποδέσμευσης της γερανιόλης προσδιορίστηκε με τα μαθηματικά κινητικά μοντέλα μηδενικής τάξης, πρώτης τάξης, Higuchi και Korsmeyer-Peppas. Οι βιοδοκιμές περιλάμβαναν την in vitro και in planta σε μαρούλια αξιολόγηση των πρωτογενών για τον έλεγχο των φυτοπαθογόνων μυκήτων B. cinerea και S. sclerotiorum και του νηματώδη M. javanica. Νανοκάψουλες με βάση Ca(OH)2 ή ZnO NPs συνδυαστικά με τη γερανιόλη, αξιολογήθηκαν ως προς την αντιμυκητιακή τους δράση έναντι του B. cinerea τόσο in vitro όσο και σε φυτά αγγουριού. Τέλος, επικαλυμμένα ZnO NPs διαφορετικού σχήματος (ακανόνιστα και ραβδοειδή) και ποσοστού επικάλυψης ολεϋλαμίνης μελετήθηκαν ως προς την επίδρασή τους στη φωτοχημεία του φωτοσυστήματος ΙΙ φυτών τομάτας

Insight into the Structural and Dynamical Processes of Peptides by Means of Vibrational and Ultrasonic Relaxation Spectroscopies, Molecular Docking, and Density Functional Theory Calculations

We report a detailed investigation of the vibrational modes, structure, and dynamics of glutathione (GSH) solutions using ultrasonic relaxation spectroscopy, FT-IR vibrational spectroscopy, and electronic absorption measurements. The experimental data were analyzed using density functional theory (DFT) and molecular docking calculations. Three distinct Debye-type relaxation processes can be observed in the acoustic spectra, which are assigned to conformational changes between GSH conformers, the self-association of GSH, and protonation processes. The standard volume changes for each process were estimated both experimentally and theoretically, revealing a close resemblance among them. The higher the effect of the relaxation process in the structure, the greater the induced volume changes. From the temperature dependence of specific acoustic parameters, the thermodynamic characteristics of each process were determined. The experimental FT-IR spectra were compared with the corresponding theoretically predicted vibrational spectra, revealing that the GSH dimers and extended conformers dominate the structure of GSH solutions in the high-concentration region. The absorption spectra in the ultraviolet region confirmed the gradual aggregation mechanism that takes place in the aqueous GSH solutions. The results of the present study were discussed and analyzed in the framework of the current phenomenological status of the field

Evidence of Self-Association and Conformational Change in Nisin Antimicrobial Polypeptide Solutions: A Combined Raman and Ultrasonic Relaxation Spectroscopic and Theoretical Study

The polypeptide Nisin is characterized by antibacterial properties, making it a compound with many applications, mainly in the food industry. As a result, a deeper understanding of its behaviour, especially after its dissolution in water, is of the utmost importance. This could be possible through the study of aqueous solutions of Nisin by combining vibrational and acoustic spectroscopic techniques. The velocity and attenuation of ultrasonic waves propagating in aqueous solutions of the polypeptide Nisin were measured as a function of concentration and temperature. The computational investigation of the molecular docking between Nisin monomeric units revealed the formation of dimeric units. The main chemical changes occurring in Nisin structure in the aqueous environment were tracked using Raman spectroscopy, and special spectral markers were used to establish the underlying structural mechanism. Spectral changes evidenced the presence of the dimerization reaction between Nisin monomeric species. The UV/Vis absorption spectra were dominated by the presence of π → π* transitions in the peptide bonds attributed to secondary structural elements such as α-helix, β-sheets and random coils. The analysis of the acoustic spectra revealed that the processes primarily responsible for the observed chemical relaxations are probably the conformational change between possible conformers of Nisin and its self-aggregation mechanism, namely, the dimerization reaction. The activation enthalpy and the enthalpy difference between the two isomeric forms were estimated to be equal to ΔH1* = 0.354 ± 0.028 kcal/mol and ΔH10 = 3.008 ± 0.367 kcal/mol, respectively. The corresponding thermodynamic parameters of the self-aggregation mechanism were found to be ΔH2* = 0.261 ± 0.004 kcal/mol and ΔH20 = 3.340 ± 0.364 kcal/mol. The effect of frequency on the excess sound absorption of Nisin solutions enabled us to estimate the rate constants of the self-aggregation mechanism and evaluate the isentropic and isothermal volume changes associated with the relaxation processes occurring in this system. The results are discussed in relation to theoretical and experimental findings

CuZn and ZnO Nanoflowers as Nano-Fungicides against Botrytis cinerea and Sclerotinia sclerotiorum: Phytoprotection, Translocation, and Impact after Foliar Application

Inorganic nanoparticles (INPs) have dynamically emerged in plant protection. The uptake of INPs by plants mostly depends on the size, chemical composition, morphology, and the type of coating on their surface. Herein, hybrid ensembles of glycol-coated bimetallic CuZn and ZnO nanoparticles (NPs) have been solvothermally synthesized in the presence of DEG and PEG, physicochemically characterized, and tested as nano-fungicides. Particularly, nanoflowers (NFs) of CuZn@DEG and ZnO@PEG have been isolated with crystallite sizes 40 and 15 nm, respectively. Organic coating DEG and PEG (23% and 63%, respectively) was found to protect the NFs formation effectively. The CuZn@DEG and ZnO@PEG NFs revealed a growth inhibition of phytopathogenic fungi Botrytis cinerea and Sclerotinia sclerotiorum in a dose-dependent manner with CuZn@DEG NFs being more efficient against both fungi with EC50 values of 418 and 311 μg/mL respectively. Lettuce (Lactuca sativa) plants inoculated with S. sclerotiorum were treated with the NFs, and their antifungal effect was evaluated based on a disease index. Plants sprayed with ZnO@PEG NFs showed a relatively higher net photosynthetic (4.70 μmol CO2 m−2s−1) and quantum yield rate (0.72) than with CuZn@DEG NFs (3.00 μmol CO2 m−2s−1 and 0.68). Furthermore, the penetration of Alizarin Red S-labeled NFs in plants was investigated. The translocation from leaves to roots through the stem was evident, while ZnO@PEG NFs were mainly trapped on the leaves. In all cases, no phytotoxicity was observed in the lettuce plants after treatment with the NFs

Impact of Geraniol and Geraniol Nanoemulsions on Botrytis cinerea and Effect of Geraniol on Cucumber Plants’ Metabolic Profile Analyzed by LC-QTOF-MS

In the present study, the bioactive substance geraniol was tested in vitro and in planta against B. cinerea on cucumber plants, and the changes in the metabolic profile of cucumber plants inoculated with the pathogen and/or treated with geraniol were monitored by a novel LC-QTOF-MS method employing target and suspect screening. The aforementioned treatments were also studied for their impact on membrane lipid peroxidation calculated as malondialdehyde (MDA) content. Additionally, geraniol-loaded nanoemulsions (GNEs) were synthesized and tested against B. cinerea as an integrated formulation mode of geraniol application. The EC50 values calculated for geraniol and GNEs against B. cinerea were calculated at 235 μg/mL and 105 μg/mL, respectively. The in planta experiment on cucumber plants demonstrated the ability of geraniol and GNEs to significantly inhibit B. cinerea under greenhouse conditions. The LC-QTOF-MS analysis of the metabolic profile of the cucumber plants treated with geraniol demonstrated an increase in the concentration levels of myricetin, chlorogenic acid, and kaempferol rhamnoside, as compared to control plants and the presence of B. cinerea caused an increase in sinapic acid and genistein. These compounds are part of important biosynthetic pathways mostly related to responses against a pathogen attack

Income deprivation and groin wound surgical site infection: cross-sectional analysis from the groin wound infection after vascular exposure multicenter cohort study

Background: Living in deprived areas is associated with poorer outcomes after certain vascular procedures and surgical site infection in other specialties. Our primary objective was to determine whether living in more income-deprived areas was associated with groin wound surgical site infection after arterial intervention. Secondary objectives were to determine whether living in more income-deprived areas was associated with mortality and clinical consequences of surgical site infection. Methods: Postal code data for patients from the United Kingdom who were included in the Groin Wound Infection after Vascular Exposure (GIVE) multicenter cohort study was used to determine income deprivation, based on index of multiple deprivation (IMD) data. Patients were divided into three IMD groups for descriptive analysis. Income deprivation score was integrated into the final multivariable model for predicting surgical site infection. Results: Only patients from England had sufficient postal code data, analysis included 772 groin incisions (624 patients from 22 centers). Surgical site infection occurred in 9.7% incisions (10.3% of patients). Surgical site infection was equivalent between income deprivation tertiles (tertile 1 = 9.5%; tertile 2 = 10.3%; tertile 3 = 8.6%; p = 0.828) as were the clinical consequences of surgical site infection and mortality. Income deprivation was not associated with surgical site infection in multivariable regression analysis (odds ratio [OR], 0.574; 95% confidence interval [CI], 0.038–8.747; p = 0.689). Median age at time of procedure was lower for patients living in more income-deprived areas (tertile 1 = 68 years; tertile 2 = 72 years; tertile 3 = 74 years; p < 0.001). Conclusions: We found no association between living in an income-deprived area and groin wound surgical site infection, clinical consequences of surgical site infection and mortality after arterial intervention. Patients living in more income-deprived areas presented for operative intervention at a younger age, with similar rates of comorbidities to patients living in less income-deprived areas. Groin wound surgical site infection (SSI) after arterial surgery is common [1], and research into reducing SSIs in vascular surgery is recognized as a priority by both clinicians and patient/caregiver representatives [2]. Despite the substantial potential morbidity and mortality of these SSIs [3,4], the available evidence relating to contributory factors is largely historic or reliant on retrospective data [5–7]. Further research on the epidemiology of SSI in this patient group is needed to allow better risk stratification, improve pre-operative discussions of risk with patients, and to guide targeted SSI prevention strategies that often include expensive prophylactic interventions [8]. However, little is currently known about the impact of socioeconomic characteristics on groin wound SSIs in this population. Socioeconomic deprivation is linked to health [9], and lifestyle-influenced cardiovascular diseases are more prevalent in more deprived areas [10]. Higher rates of unhealthy lifestyles (smoking, poor diet, and lack of physical exercise) in deprived areas are postulated to cause higher rates of cardiovascular risk increasing comorbidities, such as obesity and hyperlipidemia [10–12]. Several cardiovascular risk factors (e.g., smoking, body mass index, and diabetes mellitus), and peripheral arterial disease itself, are well recognized risk factors for SSI [13–16]. The association between socioeconomic deprivation and SSIs has previously been demonstrated in orthopedic surgery, cardiac surgery, and general surgery [17–19]. It is currently unknown whether living in an income-deprived area is associated with groin wound SSIs after arterial intervention. It was recently demonstrated in a large registry study in the United Kingdom, that outcomes following endovascular intervention for occlusive peripheral arterial disease were worse for patients living in deprived areas [20]. To the best of our knowledge, this aspect of outcomes after arterial intervention through a groin incision has not been investigated. Furthermore, studies demonstrating higher prevalence of cardiovascular disease risk factors in more deprived areas are now mostly historic and have not specifically investigated those presenting for arterial intervention through a groin incision for demographic differences in relation to deprivation [9–12]. Updated, prospective evidence is required to determine whether health inequalities persist for such patients today. Our primary objective was to determine whether residing in a more income-deprived area was associated with a higher risk of groin wound SSI after arterial intervention, by analyzing a subset of patients enrolled in the Groin wound Infection after Vascular Exposure (GIVE) multicenter cohort study [1,21]. Secondary objectives were to determine whether living in more income-deprived areas was associated with 30-day mortality and the clinical sequelae of SSI, and whether patients living in more income-deprived areas differed in terms of demographics and comorbidities compared with patients from less income-deprived areas