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"W. Carvalho"
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Toxicity of Nanoemulsified Eugenia uniflora (Myrtaceae) Essential Oil to Spodoptera frugiperda (Lepidoptera: Noctuidae) and Selectivity to Trichogramma pretiosum (Hymenoptera: Trichogrammatidae)
by
Figueiredo, Karolina G.
,
Carvalho, Geraldo A.
,
Alves, Dejane S.
in
Agricultural practices
,
Bioassays
,
bioinsecticides
2026
Spodoptera frugiperda (fall armyworm) is a polyphagous pest with widespread resistance to synthetic insecticides, while essential oils (EOs) and biological control agents, such as the parasitoid Trichogramma pretiosum, represent promising strategies in integrated pest management (IPM) programs. This study evaluated the toxicity of Eugenia uniflora EO, popularly known as pitanga EO, and nanoemulsion (NEO) to S. frugiperda and the selectivity of the NEO to T. pretiosum. The EO of E. uniflora was characterized by GC-MS/DIC and then diluted in water and Tween 80® for bioassays to estimate the LC50 against S. frugiperda in Potter’s tower. The NEOs were produced by high-shear dispersion using an Ultra-Turrax and characterized for thermal stability, particle size, polydispersity index (PDI), zeta potential (ζ), temporal stability, and morphology. The NEO was diluted to the LC50 (36.05 mg/mL) in 1% Tween 80® solution and tested for toxicity to S. frugiperda and to the parasitoid. The majority compounds in the EO from E. uniflora were curzerene (34.07%), selina-1,3,7(11)-trien-8-one (10.51%), germacrene B (9.51%) and germacrene D (5.03%). The NEO stored at 25 °C remains stable for up to 30 days after preparation. In addition, the NEO showed a particle size of 283.2 nm, a PDI of 0.289, and a zeta potential (ζ) of −23.2 mV. The E. uniflora EO and NEO at a concentration of 36.05 mg/mL were toxic to S. frugiperda (36% probability of survival). Furthermore, NEO was selective for T. pretiosum in its immature stages. The NEO proved to be stable, effective, and selective, indicating potential for IPM. However, validation under semi-field and field conditions is still necessary.
Journal Article
A new glance on root-to-shoot in vivo zinc transport and time-dependent physiological effects of ZnSO4 and ZnO nanoparticles on plants
by
Montanha, Gabriel S.
,
Pereira de Carvalho, Hudson W.
,
de Almeida, Eduardo
in
631/449/1736
,
631/57/2283
,
639/638/11
2019
Understanding nanoparticle root uptake and root-to-shoot transport might contribute to the use of nanotechnology in plant nutrition. This study performed time resolved experiments to probe Zn uptake, biotransformation and physiological effects on
Phaseolus vulgaris
(L.). Plants roots were exposed to ZnO nanoparticles (40 and 300 nm) dispersions and ZnSO
4(aq)
(100 and 1000 mg Zn L
−1
) for 48 h. Near edge X-ray absorption spectroscopy showed that 40 nm ZnO was more easily dissolved by roots than 300 nm ZnO. It also showed that in the leaves Zn was found as a mixture Zn
3
(PO
4
)
2
and Zn-histidine complex. X-ray fluorescence spectroscopy showed that root-to-shoot Zn-translocation presented a decreasing gradient of concentration and velocity, it seems radial Zn movement occurs simultaneously to the axial xylem transport. Below 100 mg Zn L
−1
, the lower stem tissue section served as a buffer preventing Zn from reaching the leaves. Conversely, it was not observed for 1000 mg Zn L
−1
ZnSO
4(aq)
. Transcriptional analysis of genes encoding metal carriers indicated higher expression levels of tonoplast-localized transporters, suggesting that the mechanism trend to accumulate Zn in the lower tissues may be associated with an enhanced of Zn compartmentalization in vacuoles. The photosynthetic rate, transpiration, and water conductance were impaired by treatments.
Journal Article
Mycorrhizal symbiosis alleviates Mn toxicity and downregulates Mn transporter genes in Eucalyptus tereticornis under contrasting soil phosphorus
by
de Andrade, Sara Adrián L
,
De Oliveira, Vinicius H
,
Montanha, Gabriel S
in
Accumulation
,
Arbuscular mycorrhizas
,
Availability
2023
Background and aimsTropical soils often present two issues that can hinder plant growth: low phosphorus (P) and high manganese (Mn) availability. Eucalyptus tereticornis is frequently cultivated in such soils. We investigated the effects of Mn in E. tereticornis under contrasting soil P availability and hypothesized that arbuscular mycorrhizal (AM) symbiosis could alleviate Mn toxicity by improving P nutrition and altering the expression of Mn transporter genes.MethodsInoculated (AM) and non-inoculated (NM) seedlings grew for seven months in a soil with low or sufficient P availability, under three Mn doses: control, 75 and 150 mg kg−1 Mn. We assessed growth, AM colonization, nutrient concentrations, and the expression of eight genes related to Mn transport and homeostasis in roots. Mn distribution at one-leaf level was determined by μ-XRF.ResultsLow P exacerbated Mn toxicity and hindered plant growth. Mycorrhizal symbiosis did not influence Mn accumulation, but improved growth and Mn tolerance at low P, partly by improving P nutrition. At sufficient P, foliar Mn reached 3500 mg kg−1, and μ-XRF patterns suggest preferential accumulation in the leaf lamina compared to margins or midribs. In NM plants, the vacuolar transporters EtVIT1 and EtMTP8 and the Mn-nicotianamine influx transporter EtYSL6 were the most responsive genes to Mn, while in AM roots most were downregulated.ConclusionVacuolar sequestration and transport of complexed Mn are important mechanisms behind Mn tolerance in E. tereticornis. We propose that Mn is transported via the mycorrhizal pathway, explaining why it does not elicit the same molecular response observed in NM roots.
Journal Article
Biodegradable Films and Edible Coatings Based on Whey Protein Isolate for Extending the Shelf Life of Commercial Strawberries
by
Comettant-Rabanal, Raúl
,
da Silveira, Michelle Fernandes
,
Loayza-Salazar, Sheyla
in
Biodegradability
,
Biodegradation
,
Biopolymers
2025
This study aimed to create a unique WPI film formulation that would help maintain strawberry quality. Therefore, an edible coating from WPI was developed, and its physical, mechanical, and rheological characteristics were analysed. WPI is a biopolymer residue with attractive barrier characteristics, biodegradability, and neutral taste that can be used as an edible coating on fragile fruits such as strawberries. Key innovations from this research include a comprehensive evaluation of whey as the sole polymeric component in edible coatings for strawberries, assessing its standalone protective potential; improvement of film formulation based on whey proportion; and an inferred shelf-life extension of whey-coated strawberries aligned with commercial acceptability standards, bridging the gap between research and practical application. This study showed that increasing protein proportion reduced the film’s solubility from 47.6% to 22.4%, thus enhancing its water resistance by up to 2-fold. Still, the film became tensile stiffer and more elastic modulus at 50% RH than at 70% RH. The filmogenic solution’s viscosity enhanced from 2.25 at 25 °C to 4.19 Pa.sn at 4 °C, indicating homogeneous coating of the fruit surface at room temperature and its adhesion at storage temperature. During cold storage, WPI coating reduced the mass loss of strawberries from a range of 5.83–16.71% in the control to a range of 2.56–13.22%, thus decreasing the mass loss by up to 2-fold compared to uncoated fruit from the control treatment, which resulted in better visual quality and a 33% extension of the shelf life of commercial strawberries. Overall, WPI films and coatings have the potential to offer a sustainable and effective protective layer for highly perishable and delicate fruits, extending shelf life and, consequently, reducing waste. Together, these properties can revolutionise the fresh produce industry to enhance global supply chain efficiency.
Journal Article
Impact of Whole Cereal–Pulse Flours on the Functionality and Antioxidant Properties of Gluten-Free Extruded Flours
by
Mellinger, Caroline Grassi
,
Chuqui-Paulino, Franz J.
,
Chávez, Davy W. Hidalgo
in
Absorption
,
Antioxidants
,
bioactive compounds
2025
Extruded whole flours from blends of cereals and pulses have great potential to be key ingredients in the development of more innovative gluten-free products, both from a technological and nutritional perspective. The objective of this work was to obtain pre-cooked flours from four formulations based on blends of whole cereals (PR: parboiled brown rice; PM: pearl millet) and pulses (CP: chickpea; CB: common bean). CB was fixed at 10%, and the other components (PR-PM-CP) were set at 60-15-15 (F1), 15-60-15 (F2), 15-15-60 (F3), and 30-30-30 (F4), which were extruded at two combined conditions of feed moisture and screw speed: mild E1 (30% and 300 rpm) and severe E2 (18% and 600 rpm). The temperature profile was kept constant from 25 to 130 °C (from feed to output). The protein, dietary fiber, and ash contents in the raw formulations varied from 11.2 to 17.4%, 9.8 to 15.0%, and 2.2 to 3.3%, respectively, according to the low or high pulse content in the blend. As more mechanical energy was delivered to the raw formulations (W·h/kg, 63.7 for E1 and 179.4 for E2), the extruded particles had increased water absorption (g/g) from 1.7 to 4.5 (E1) or 3.8 (E2), increased water solubility due to E2 from 10.9 to 20.9%, and decreased oil absorption (g/g) from 1.5 to 0.9 (E1 and E2). The peak viscosity (PV, cP) was noticeable only in the raw formulation F2 (355), which decreased 10.3% due to E1. In the other formulations, PV appeared due to E1 in F1 (528), F3 (420), and F4 (371), while it disappeared due to E2 in all formulations. However, at the E2 condition, they did show cold viscosity in the initial stage (222 to 394 cP). The final viscosity (FV, cP) decreased from 795 to 390 (E1) or 123 (E2). In F2, the contents of phenolic compounds (285 µg GAE/g) and ABTS+ (13.2 μmol TE/g) were more than twice that in the other formulations, and their respective degradations were low due to E1 (4.2 and 12%) and high due to E2 (16 and 17%). Extrusion cooking did not cause significant changes in the luminosity (81) and redness (0.9) of particles, while yellowness increased from 15.7 to 18.2 (E1) or 18.7 (E2). Based on these findings, it is concluded that both extrusion conditions improved the technological and functional properties. Regarding the formulations, F2 stood out for being rich in antioxidant capacity, which poorly degraded under the conditions studied. Further work is needed to contribute to understanding the optimization of formulas and processes that would improve the nutritional, sensorial, and functional properties while still preserving the bioactive value of the final products.
Journal Article
Laboratory Microprobe X-Ray Fluorescence in Plant Science: Emerging Applications and Case Studies
by
Carvalho, Hudson W. P.
,
Duran, Nádia M.
,
Gomes, Marcos H. F.
in
absorption and transport of nutrients
,
Anthracnose
,
Atoms & subatomic particles
2018
and micro chemical analytical methods have the potential to improve our understanding of plant metabolism and development. Benchtop microprobe X-ray fluorescence spectroscopy (μ-XRF) presents a huge potential for facing this challenge. Excitation beams of 30 μm and 1 mm in diameter were employed to address questions in seed technology, phytopathology, plant physiology, and bioremediation. Different elements were analyzed in several situations of agronomic interest: (i) Examples of μ-XRF yielding quantitative maps that reveal the spatial distribution of zinc in common beans (
) primed seeds. (ii) Chemical images daily recorded at a soybean leaf (
) infected by anthracnose showed that phosphorus, sulfur, and calcium trended to concentrate in the disease spot. (iii)
measurements at the stem of
showed that under root exposure, manganese is absorbed and transported nearly 10-fold faster than iron. (iv) Quantitative maps showed that the lead distribution in a leaf of
hybrid was not homogenous, this element accumulated mainly in the leaf border and midrib, the lead hotspots reached up to 13,400 mg lead kg
fresh tissue weight. These case studies highlight the ability of μ-XRF in performing qualitative and quantitative elemental analysis of fresh and living plant tissues. Thus, it can probe dynamic biological phenomena non-destructively and in real time.
Journal Article
Bioplastics of Native Starches Reinforced with Passion Fruit Peel
by
Moro, Thaisa M. A.
,
Ortiz, Juan A. R.
,
Carvalho, Carlos W. P.
in
Agriculture
,
Bioplastics
,
Biotechnology
2017
Industrial passion fruit juice production generates a large amount of passion fruit waste, which contains about 60% of fibers when dried and could be used as reinforcement of thermoplastic starch. This study aimed to develop an extruded starchy bioplastic reinforced with passion fruit peel (Pfp) (0, 4, 10, 16, and 20%), glycerol (60, 64, 70, 76, and 80 wt%), and starch mix (55% corn and 45% cassava) that were processed at varied screw speeds (66, 80, 100, 120, and 134 rpm). The response surface methodology was applied to analyze the effects of Pfp, glycerol, and screw speed. Mechanical properties, contact angle, and water permeability and solubility were the response variables. Addition of Pfp, up to 4%, improved the bioplastic mechanical properties. High addition of Pfp (16 and 20%) combined with the lowest screw speed (66 rpm) reduced bioplastic water solubility. Water vapor permeability slightly increased with the combination of increasing glycerol content and screw speed. Contact angle was not statically affected by the independent variables. The extrusion showed as an interesting tool that provided greater homogeneity of Pfp incorporated in starch bioplastic, though the mix would benefit from finer Pfp particle size distribution.
Journal Article
Characterization of spray-dried nanofibrillated cellulose and effect of different homogenization methods on the stability and rheological properties of the reconstituted suspension
by
Carvalho Carlos W P
,
Tonon, Renata V
,
Furtado, Maraysa R
in
Amplitudes
,
Cellulose
,
Eucalyptus
2021
In the present study, a suspension of nanofibrillated cellulose from eucalyptus was spray-dried in order to obtain a powdered material that could be easily transported and stored. The original suspension and the dried material were characterized for their physical, morphological and thermal properties. An increase in crystallinity and reduction in thermal stability were observed after drying. In addition, the fibrils size passed from nano to micro scale The powder obtained was rehydrated and homogenized by two methods: rotor-stator homogenization (5000, 10,000 and 15,000 rpm) and ultrasound (10, 30 and 50% maximum amplitude), during 3 and 5 min, in order to verify the possibility of obtaining a stable reconstituted suspension comparable to the original one. Higher treatment intensities resulted in suspensions with higher viscosity and stability. The suspension homogenized by ultrasound at 50% amplitude for 5 minutes was the most stable one and restored the nano dimensions of the original suspension. Both the original and the reconstituted suspensions showed a shear thinning and “gel-like” behavior. Higher Ultra-Turrax speed and ultrasound amplitude resulted in higher viscoelastic modulus (G′ and G″), although these values were lower than those found in the initial nanocellulose suspension.Graphic abstract
Journal Article