Mannans: Structural carbohydrates produced during seed maturation in Euterpe edulis Martius, an Atlantic Forest species vulnerable to extinction.

Palm seedlings are visually selected from mature fruits in a slow process that leads to nonuniform germination and high embryo mortality. In this study, we determined the levels of monosaccharides, their crystallinity, and their role in the formation of Euterpe edulis endosperm during seed maturation. Seeds harvested from 108 to 262 days after anthesis (DAA) were analyzed morphologically, physiologically, and chemically to measure soluble and insoluble lignins, ashes, structural carbohydrates, degree of crystallinity, and endo-ß-mannanase. The seeds achieved maximum germination and vigor at 164 DAA. During the early stages, only compounds with a low structural order were formed. The contents of soluble and insoluble lignins, ashes, glucans, and galactans decreased during maturation. Those of mannans, the main structural carbohydrate in the endosperm, increased along with the degree of crystallinity, as suggested by a mannan-I-type X-ray diffraction pattern. Similarly, endo-ß-mannanase activity peaked at 262 DAA. The superior physiological outcome of seeds and seedlings at 164 DAA implies a 98-day shorter harvesting time. The state of mannans during seed maturation could be used as a marker to improve seedling production by E. edulis.

Functional Fruit Trees from the Atlantic and Amazon Forests: Selection of Potential Chestnut Trees Rich in Antioxidants, Nutrients, and Fatty Acids.

The Amazon rainforest and the biodiversity hotspot of the Atlantic Forest are home to fruit trees that produce functional foods, which are still underutilized. The present study aimed to select potential functional nut donor trees from two Brazilian chestnuts, by evaluating the nutritional and antioxidant composition of the nuts and the fatty acid profile of the oil. The nutritional characteristics, antioxidants, oil fatty acid profile, and X-ray densitometry of the nuts were evaluated, as well as the characterization of leaf and soil nutrients for each parent tree. The nut oil was evaluated through Brix (%), mass (g), yield (%), and the fatty acid profile. For L. pisonis, the most nutritious nuts were produced by L. pisonis tree 4 (N > P > K > Mg > Ca > Zn > Fe) and L. pisonis tree 6 (P > Ca > Mg > Mn > Zn > Cu > Fe), and for the species L. lanceolata, L. lanceolata tree 6 (N > P > Ca > Mg > Zn > Fe > Cu) and L. lanceolata tree 2 (P > K > Mg > Zn > Cu). In L. pisonis, the highest production of anthocyanins, DPPH, total phenolics, and flavonoids was obtained from the nuts of L. pisonis tree 4 as well as for L. lanceolata, from L. lanceolata tree 1, except for flavonoids. The Brix of the oil from the nuts of both species showed no difference between the trees and the fatty acid profile with a similar amount between saturated (48-65%) and unsaturated (34-57%) fatty acids. Both species have nuts rich in nutrients and antioxidant compounds and can be considered unconventional functional foods. The data collected in the present study confirm that the nuts of these species can replace other foods as a source of selenium.

Germination, cytotoxicity, and mutagenicity in Lactuca sativa L. and Passiflora alata Curtis in response to sewage sludge application.

The physical and chemical characteristics of the soil can influence plant growth. When sewage sludge (SS) is applied as a soil fertilizer, the accumulation of non-essential elements contained in it can be toxic for plants. The aim of this study was to understand the effect of SS dosage on the cell cycle of Lactuca sativa L. meristematic cells and on the initial growth of L. sativa and Passiflora alata Curtis. Nine concentrations of SS + distilled water (mg dm-3) corresponding to 0, 20, 40, 60, 80, 120, 160, 320, and 520 t ha-1 were tested in four replicates of 25 seeds. Chemical analysis showed an increase in pH of the sludge from 0 to 80 t ha-1 SS followed by its stabilization thereafter. The highest electrical conductivity was observed at 520 t ha-1 SS. SS negatively affected the germination and initial growth of seedlings from P. alata and L. sativa. Cytogenetic analysis on 6000 L. sativa meristematic cells for each treatment revealed that SS could adversely affect the genetic stability of this species. SS concentrations above 120 t ha-1 adversely affected the germination and early seedling growth of L. sativa and P. alata. At high concentrations (120 t ha-1), SS induced genetic lesions in L. sativa, along with chromosomal and nuclear alterations.

Pickering Emulsions Based in Inorganic Solid Particles: From Product Development to Food Applications.

Pickering emulsions (PEs) have attracted attention in different fields, such as food, pharmaceuticals and cosmetics, mainly due to their good physical stability. PEs are a promising strategy to develop functional products since the particles' oil and water phases can act as carriers of active compounds, providing multiple combinations potentiating synergistic effects. Moreover, they can answer the sustainable and green chemistry issues arising from using conventional emulsifier-based systems. In this context, this review focuses on the applicability of safe inorganic solid particles as emulsion stabilisers, discussing the main stabilisation mechanisms of oil-water interfaces. In particular, it provides evidence for hydroxyapatite (HAp) particles as Pickering stabilisers, discussing the latest advances. The main technologies used to produce PEs are also presented. From an industrial perspective, an effort was made to list new productive technologies at the laboratory scale and discuss their feasibility for scale-up. Finally, the advantages and potential applications of PEs in the food industry are also described. Overall, this review gathers recent developments in the formulation, production and properties of food-grade PEs based on safe inorganic solid particles.

Luminosity, temperature, and substrates on the germination of Solanum capsicoides

Solanum capsicoides, commonly known as red soda apple, is a little-studied species with phytotherapeutic characteristics of interest to the pharmaceutical industry. However, little is known about its agronomic characteristics. Therefore, this study aimed to assess the effect of light, different temperatures, and substrates on the germination of S. capsicoides seeds. The study consisted of two experiments: Experiment I - Germination of S. capsicoides seeds under different wavelengths. The seeds were kept on Petri dishes covered with Germitest™ paper moistened with distilled water and exposed to the monochromatic, red, far-red, and dark wavelengths. The experiment was performed in a completely randomized design with four replications of 25 seeds. Experiment II - Germination of S. capsicoides seeds on different substrates and at different temperatures. The seeds were distributed according to six substrates: paper roll, on paper, between sand, on sand, on soil + sand + manure, and between soil + sand + manure. The seeds were also subjected to the constant temperatures of 20, 25, 30, and 35 °C and the alternate temperatures of 20-30, 20-35, 25-30, and 25-35 °C, characterizing a 6 x 8 factorial arrangement. Germination rate, germination speed index, and mean germination time were evaluated. Red soda apple seeds are classified as positive photoblastic, with the highest germination rate occurring at the temperature of 20-35 °C combined with on paper, paper roll, on sand, and between sand substrates.

Sapucaia nut: Morphophysiology, minerals content, methodological validation in image analysis, phenotypic and molecular diversity in Lecythis pisonis Cambess.

Sapucaia or Lecythis pisonis Cambess. is an ornamental tree that produces edible, tasty, and nutritious nuts, and can be used for timber production. Sapucaia has potential as a functional food, owing to optimal nutritional and particularly Se levels. The present study sought to characterize the seeds of 21 sapucaia matrices from forest remnants of a neotropical hotspot (Atlantic Forest) and farms in two Brazilian states. Biometrics, germination, vigor, lignin content in the teguments, minerals content, and phenotypic and molecular diversity were analyzed. The seeds of matrices 16 and 21 were the most vigorous. Nuts from matrices 21 and 17 contained the highest amounts of Se. Matrices 5, 8, and 21 were the most phenotypically distant; whereas matrix 21 was the most genetically distant. Importantly, we validated a new non-destructive and efficient X-ray-based methodology for internal and densitometric analysis of sapucaia seeds, and demonstrated a high genetic divergence among matrices.

Removal of bromate from drinking water using a heterogeneous photocatalytic mili-reactor: impact of the reactor material and water matrix.

The main goal of this study was to evaluate the removal of bromate from drinking water using a heterogeneous photocatalytic mili-photoreactor, based on NETmix technology. The NETmix mili-reactor consists of a network of channels and chambers imprinted in a back slab made of acrylic (AS) or stainless steel (SSS) sealed, through mechanical compression and o-rings, with an UVA-transparent front borosilicate glass slab (BGS). A plate of UVA-LEDs was placed above the BGS window. TiO2-P25 thin films were immobilized on the BGS (back-side illumination, BSI) or SSS (front-side illumination, FSI) by using a spray deposition method. The photoreduction rate of a 200 µg L-1 (1.56 µM) BrO3- solution was assessed taking into account the following: (i) catalyst film thickness, (ii) catalyst coated surface and illumination mechanism (BSI or FSI), (iii) solution pH, (iv) type and dose of sacrificial agent (SA), (v) reactor material, and (vi) water matrix. In acidic conditions (pH 3.0) and in the absence of light/catalyst/SA, 28% and 36% of BrO3- was reduced into Br- only by contacting with AS and SSS during 2-h, respectively. This effect prevailed during BSI experiments, but not for FSI ones since back SSS was coated with the photocatalyst. The results obtained have demonstrated that (i) the molar rate of disappearance of bromates was similar to the molar rate of formation of bromides; (ii) higher BrO3- reduction efficiencies were reached in the presence of an SA using the FSI at pH 3.0; (iii) formic acid ([BrO3-]:[CH2O2] molar ratio of 1:3) presented higher performance than humic acids (HA = 1 mg C L-1) as SA; (iv) high amounts of HA impaired the BrO3- photoreduction reaction; (v) SSS coated catalyst surface revealed to be stable for at least 4 consecutive cycles, keeping its photonic efficiency. Under the best operating conditions (FSI, 18 mL of 2% wt. TiO2-P25 suspension, pH 3.0), the use of freshwater matrices led to (i) equal or higher reaction rates, when compared with a synthetic water in the absence of SA, and (ii) lower reaction rates, when compared with a synthetic water containing formic acid with a [BrO3-]:[CH2O2] molar ratio of 1:3. Notwithstanding, heterogeneous TiO2 photocatalysis, using the NETmix mili-reactor can be used to promote the reduction of BrO3- into Br-, attaining concentrations below 10 µg L-1 (guideline value) after 2-h reaction. Graphical Abstract .

Somatic embryogenesis in the commercial papaya hybrid UENF/Caliman 01 relying on plantlet production from sexed adult hermaphrodite donor plants.

Somatic embryogenesis from explants from hermaphrodite papaya mother plants is an alternative for the production of true-to-type plants without the need for sexing. This study aimed to analyze hormonal and osmotic inducers in different somatic embryogenesis stages in the commercial hermaphrodite hybrid papaya UENF/Caliman 01. Leaf disks from in vitro shoots originated from ex vitro hermaphrodite plants were cultured in induction medium supplemented with different concentrations of 2,4-D (6, 9, 12, 15, and 18 µM) and 4-CPA (19, 22, 25, 28, and 31 µM). After 90 days, the formation of somatic embryos was verified. The 2,4-D induced the formation of light brown calli with low frequency (20%) of somatic embryogenesis. However, 4-CPA (25 µM) induced 96% of embryogenic calli, which were transferred to maturation medium (MM) and cultured for 30 days. The MM contained ABA (0.5 µM) and AC (15 g L-1) and produced 36.6 somatic embryos callus-1, mainly on cotyledonary stage. Cotyledonary embryos were transferred to germination medium supplemented with gibberellic acid (GA3) (0.0, 1.44, 2.88, and 4.32 µM), and the conversion into plantlets was enhanced with GA3 at 2.88 µM.

Intensification of heterogeneous TiO2 photocatalysis using the NETmix mili-photoreactor under microscale illumination for oxytetracycline oxidation.

This study focuses on the intensification of heterogeneous TiO2 photocatalysis for the removal of a contaminant of emerging concern (CEC), oxytetracycline (OTC), as a polishing step of urban wastewaters, using an innovative NETmix mili-photoreactor under UVA-LEDs illumination. The effect of catalyst coated surface per reactor volume and the illumination mechanism, back-side (BSI) or front-side (FSI) irradiation, on OTC oxidation were evaluated. For that, a thin film of photocatalyst was uniformly deposited on the front borosilicate slab (BS) (BSI mechanism; 333 m2catalyst m-3reactor) or on the network of channels and chambers imprinted in the back stainless-steel slab (SSS) (FSI mechanism; 989 m2catalyst m-3reactor) using a spray system. OTC removal was also assessed as a function of TiO2 film thickness immobilized on both slabs. The photocatalyst reactivity in combination with photoreactor was significantly enhanced (3.4 times) from 0.64 to 2.19 mmolOTC m-3illuminated reactor volume s-1, when considering the BSI and FSI mechanisms, respectively. In addition, the influence of UVA-LEDs intensity on OTC oxidation rate was investigated. UVA-LEDs plates were placed on the top of the NETmix borosilicate window. Moreover, the effect of water matrix was assessed using a secondary effluent from an urban wastewater treatment plant fortified with OTC. OTC oxidation rate was only inhibited in about 1.3 times in the presence of the real matrix, showing the ability of the NETmix to overcome matrix effects due to its unique characteristics. Catalyst film stability over four consecutive reaction cycles was evaluated using synthetic and real matrices fortified with OTC.

Selecting the best piping arrangement for scaling-up an annular channel reactor: An experimental and computational fluid dynamics study.

This study is focused on the selection of the best piping arrangement for a pilot scale annular channel reactor intended for the remediation of waters and wastewaters. Two annular channel reactors composed of a single UV lamp and distinct piping arrangements were considered: (i) a novel reactor with tangential inlet/outlet pipes - the FluHelik reactor, and (ii) a conventional Jets reactor. These two reactors were manufactured at lab scale and characterized in terms of residence time distribution (RTD), radiant power and ability to degrade aqueous solutions spiked with a model compound - 3-amino-5-methylisoxazole (AMI) - by H2O2/UVC and UVC processes. Computational fluid dynamics (CFD) simulations were used to assess the hydrodynamics, RTD and UV radiation intensity distribution of both reactors at pilot scale. In general, experimental results at lab scale revealed quite similar RTDs, radiant powers and AMI degradation rates for both reactors. On the other hand, CFD simulations at pilot scale revealed the generation of a helical motion of fluid around the UVC lamp in the FluHelik reactor, inducing: (i) a longer contact time between fluid particles and UV light, (ii) more intense dynamics of macromixing as a result of larger velocity gradients, turbulent intensities and dispersion of RTD values around the peak, and (iii) a more homogeneous UV radiation distribution. In addition, the design of the FluHelik reactor can favor the implementation of various reactors in series, promoting its application at industrial scale. The FluHelik reactor was chosen for scaling-up. A pre-pilot scale treatment unit containing this reactor was constructed and its feasibility was proven.

Overcoming limitations in photochemical UVC/H2O2 systems using a mili-photoreactor (NETmix): Oxytetracycline oxidation.

This study focuses on the intensification of a photochemical UVC/H2O2 system using a mili-photoreactor (NETmix) for a better and faster elimination of oxytetracycline (OTC) from urban wastewater. This mili-photoreactor comprises a network of small cylindrical chambers and prismatic transport channels sealed by a UVC transparent quartz slab allowing unique properties. Since light has a profound effect on the photochemical process, UVC photons distribution over the reaction medium was investigated using a multiple UVC lamp design (4, 6 or 11 W) allocated in parallel or perpendicular to the solution movement. In addition, the effect of other operating variables, such as oxidant dosage (100-900 mg L-1), oxidant feed configuration (single entry or continuous multi-injection) and flow rate (50-100 L h-1) was studied. A kinetic model able to describe the OTC oxidation by the UVC/H2O2 photochemical system in the mili-photoreactor was also developed. Moreover, matrix effect was evaluated by spiking OTC in a secondary effluent from an urban WWTP. In this case, OTC degradation was inhibited in about 2 to 3 times due to the presence of organic/inorganic substances (soluble and particulate), inherent to the real matrix, that act as scavenger of oxidant species and as UVC light filter. The NETmix mili-photoreactor presented high photochemical space time yield (PSTY) values when compared with a conventional tubular photoreactor. This highlights the NETmix capacity to enhance UVC/H2O2 processes through an homogeneous light distribution over the entire reaction medium.

Intensifying heterogeneous TiO2 photocatalysis for bromate reduction using the NETmix photoreactor.

This work focuses on the intensification of BrO3- (200 µg L-1) reduction by TiO2-assisted heterogeneous photocatalysis, using the NETmix mili-photoreactor illuminated by UVA light-emitting diodes (UVA-LEDs). The mili-photoreactor was assembled in two configurations: i) catalyst deposition on the channels and chambers of a back stainless steel slab (SSS) and ii) catalyst deposition on the front borosilicate glass slab (BGS), allowing the study of front-side (FSI) and back-side (BSI) illumination mechanisms, respectively. The BrO3- reduction rate in aqueous solution was assessed as a function of: i) pH; ii) dissolved oxygen (DO); iii) addition of formic acid (CH2O2) as a sacrificial agent (SA); iv) photocatalyst film thickness; v) illumination mechanism; vi) irradiation intensity; vii) temperature; and viii) water matrix. Higher BrO3- reduction rates were observed using the FSI mechanism and lower pH values. Nitrogen injection (to eliminate DO) did not significantly improve the reaction rate and the addition of CH2O2 had a negative effect at pH 6.5. Neither temperature nor irradiance increase showed a considerable improvement on the reduction rate. Moreover, TiO2 film remains stable for at least 13 consecutive reactions without significant catalyst leaching. The chemically pre-treated fresh water (FW) matrix negatively affected the reaction rate when compared with the synthetic water (SW), under the best operational conditions (SSS: pH = 5.5, 287 mg of TiO2, 25 °C, SA absence, [DO] = 232-263 µM). This was associated with the presence of both inorganic and organic matter at much higher concentrations than BrO3-. Notwithstanding, heterogeneous TiO2 photocatalysis, using the NETmix mili-photoreactor, was successfully applied to fresh water, achieving [BrO3-] < 10 µg L-1 (guideline value) after 2-hour reaction.

Morphology and Ontogeny of Statoliths in the Grooved Carpet Shell, Ruditapes decussatus.

Statoliths are nonskeletal calcified structures included in most invertebrates' gravireceptors. They have been identified and characterized in several gastropod and cephalopod molluscs and have proved to be very useful for age estimation, growth studies, and connectivity analysis, among other applications. Beyond the scarce available records on their occurrence in Class Bivalvia, statoliths are yet to be documented in the grooved carpet shell, Ruditapes decussatus, a species of high ecological and commercial value. An easy method for the extraction and processing of R. decussatus statoliths is described herein. The statolith growth was followed from the initial shell length (SL) of 2.5-3.5 mm (seed commercial size T1.5) for a period of 6 months in a nursery facility located in the Ria de Aveiro (an estuarine system in NW Portugal). The relationship between statolith diameter (StD) and SL follows the function StD=14.305 SL0.254 (N=173; r=0.855, p<0.001). All statoliths observed showed similar morphostructure and general chemistry: hard, translucent spheres of crystalline calcium oxalate (whewellite), with a central nucleus delimited by a growth check of 6.7±1.0 µm in diameter, possibly as a result of growth arrest during metamorphosis, a metamorphic ring, as described for their gastropod counterparts. Subsequent studies should validate this and will involve a search for the occurrence of additional checks that may potentially be present in older specimens and if they are, would open a new range of most promising applications for bivalve statoliths.

The effects of an osmoregulator, carbohydrates and polyol on maturation and germination of 'Golden THB' papaya somatic embryos.

This study evaluated the effect of osmoregulators and carbohydrates on the maturation and germination of somatic embryos of papaya 'Golden THB'. Cotyledon explants from papaya seedlings germinated in vitro on basal MS medium were cultured on somatic embryogenesis induction medium (IM) containing MS salts, myo-inositol, sucrose, agar and p-chlorophenoxyacetic acid. After 50 days, embryogenic calli were transferred onto maturation media (MM) for 45 additional days. For experiment 1, a MS-based medium supplemented with abscisic acid, activated charcoal and concentrations of PEG 6000 (0; 40; 50; 60 and 70 g L-1) was used, whereas for experiment 2 malt extract concentrations (0; 0.1; 0.2; 0.3 and 0.4 g L-1) were assessed. The normal cotyledonary somatic embryos produced in experiment 2 were transferred to the germination medium (GM). The GM consisted of full-strength MS medium, sucrose, agar and was supplemented with myo-inositol at varying concentrations (0; 0.275; 0.55 and 0.825 mM). The PEG concentrations tested impaired the maturation of 'Golden THB' papaya somatic embryos. The MM, supplemented with malt extract at 0.153 g L-1, promoted the greatest development of normal somatic embryos (18.28 SE calli-1), that is, two cotyledonary leaves produced 36.56 SE calli-1. The supplementation with 0.45 mM myo-inositol provided the highest germination percentage (47.42%) and conversion to emblings.

Retrato de uma região: impacto da indústria sucroalcooleira, indicadores de saúde e a percepção dos gestores / Pictures from a region: impact of the sugarcane industry, health indicators and managers' perception

Resumo Este artigo analisa indicadores de saúde dos municípios da região de São José do Rio Preto e a demanda da população segundo os gestores diante do processo de expansão da cana de açúcar. Dez municípios da região que possuem usinas de cana de açúcar e outros 10 municípios com o mesmo número de habitantes, mas sem usinas, foram selecionados. Os dados foram coletados por meio de entrevistas e em bancos de dados do Ministério da Saúde. Observou-se que, independentemente da presença de usinas sucroalcooleiras, houve melhora nos indicadores de saúde. Entretanto, para os gestores entrevistados, independentemente da presença ou ausência de usinas, a presença de migrantes para o corte da cana piorou os indicadores de saúde. Assim, constatou-se que a presença de usinas nos municípios não interferiu nos indicadores de saúde, mas os gestores consideram que a qualidade da saúde do município teve queda.

Abstract This article analyzes health indicators in the municipalities of the São José do Rio Preto region (state of São Paulo, Brazil) and the demand of the population according to the managers regarding the sugar cane expansion process. Ten municipalities in the region that have sugar cane mills and 10 other municipalities with the same number of inhabitants, but without the presence of plants, were selected. Data were collected through interviews and Ministry of Health databases. It was observed that, regardless of the presence of sugar and alcohol plants, there was an improvement in health indicators. However, to the interviewed managers, despite there being plants or not, the presence of migrants to cut sugarcane worsened health indicators. Therefore, it was observed that the presence of plants in the municipalities did not interfere in health indicators, but managers perceived a drop in health quality in the municipality.

Application of a micro-meso-structured reactor (NETmix) to promote photochemical UVC/H2O2 processes - oxidation of As(iii) to As(v).

A micro-meso-structured reactor (NETmix) was used for the first time to promote photochemical UVC/H2O2 processes. The NETmix photoreactor consists of a network of chambers and channels, where the liquid flows, sealed with a quartz slab with high UVC transparency. Due to the small size of channels and chambers, the NETmix presents a uniform irradiance through the entire reactor depth, short molecular diffusion distances and large specific interfacial areas, maximizing the pollutant/oxidant contact. In this study, the NETmix photoreactor was evaluated for As(iii) oxidation to As(v) using a photochemical UVC/H2O2 system. The effect of the UVC lamp power (4, 6 or 11 W), the number of UVC lamps (2 or 3 lamps) and the UVC lamp layout (parallel or perpendicular to the flow direction) was evaluated, in order to ensure uniform irradiation of the entire reaction mixture. The optimum H2O2 concentration for each light distribution system was also evaluated. At the best configuration, 3 lamps of 11 W positioned parallel to the flow direction, total As(iii) oxidation ([As(iii)]0 = 1.33 × 10-2 mM) was achieved in 15 min with an absorbed photon flux density of 1.9 × 10-1 einstein per m3 per s. Significant differences were highlighted between the photon flux actually received in the photoreactor and the radiant power emitted by the lamp. A kinetic model able to represent the As(iii) oxidation employing UVC radiation and H2O2 in a micro-meso-structured reactor was presented. The photochemical space time yield (PSTY) values obtained for the micro-meso-structured reactor are higher than for conventional batch reactors, showing that the NETmix technology can be a good solution for application in photochemical processes.

Strategies to reduce mass and photons transfer limitations in heterogeneous photocatalytic processes: Hexavalent chromium reduction studies.

The current work presents different approaches to overcome mass and photon transfer limitations in heterogeneous photocatalytic processes applied to the reduction of hexavalent chromium to its trivalent form in the presence of a sacrificial agent. Two reactor designs were tested, a monolithic tubular photoreactor (MTP) and a micro-meso-structured photoreactor (NETmix), both presenting a high catalyst surface area per reaction liquid volume. In order to reduce photon transfer limitations, the tubular photoreactor was packed with transparent cellulose acetate monolithic structures (CAM) coated with the catalyst by a dip-coating method. For the NETmix reactor, a thin film of photocatalyst was uniformly deposited on the front glass slab (GS) or on the network of channels and chambers imprinted in the back stainless steel slab (SSS) using a spray system. The reaction rate for the NETmix photoreactor was evaluated for two illumination sources, solar light or UVA-LEDs, using the NETmix with the front glass slab or/and back stainless steel slab coated with TiO2-P25. The reusability of the photocatalytic films on the NETmix walls was also evaluated for three consecutive cycles using fresh Cr(VI) solutions. The catalyst reactivity in combination with the NETmix-SSS photoreactor is almost 70 times superior to one obtained with the MTP.

Somatic embryogenesis in Carica papaya as affected by auxins and explants, and morphoanatomical-related aspects

ABSTRACT The aim of this study was to evaluate somatic embryogenesis in juvenile explants of the THB papaya cultivar. Apical shoots and cotyledonary leaves were inoculated in an induction medium composed of different concentrations of 2,4-D (6, 9, 12, 15 and 18 µM) or 4-CPA (19, 22, 25, 28 and 31 µM). The embryogenic calluses were transferred to a maturation medium for 30 days. Histological analysis were done during the induction and scanning electron microscopy after maturing. For both types of auxin, embryogenesis was achieved at higher frequencies with cotyledonary leaves incubated in induction medium than with apical shoots; except for callogenesis. The early-stage embryos (e.g., globular or heart-shape) predominated. Among the auxins, best results were observed in cotyledonary leaves induced with 4-CPA (25 µM). Histological analyses of the cotyledonary leaf-derived calluses confirmed that the somatic embryos (SEs) formed from parenchyma cells, predominantly differentiated via indirect and multicellular origin and infrequently via synchronized embryogenesis. The secondary embryogenesis was observed during induction and maturation phases in papaya THB cultivar. The combination of ABA (0.5 µM) and AC (15 g L-1) in maturation medium resulted in the highest somatic embryogenesis induction frequency (70 SEs callus-1) and the lowest percentage of early germination (4%).

Inorganic Hg toxicity in plants: A comparison of different genotoxic parameters.

Inorganic Mercury (Hg) contamination persists an environmental problem, but its cyto- and genotoxicity in plants remains yet unquantified. To determine the extent of Hg-induced cyto- and genotoxicity, and assess most sensitive endpoints in plants, Pisum sativum L. seedlings were exposed for 14 days to different HgCl2 concentrations up to 100 µM. Shoots and roots from hydroponic exposure presented growth impairment and/or morphological disorders for doses >1 µM, being the roots more sensitive. Plant growth, ploidy changes, clastogenicity (HPCV), cell cycle dynamics (G1-S-G2), Comet-tail moment (TM), Comet-TD, Mitotic-index (MI) and cell proliferation index (CPI) were used to evaluate Hg-induced cyto/genotoxicity. Both leaf and root DNA-ploidy levels, assessed by flow cytometry (FCM), remained unaltered after exposure. Root cell cycle impairment occurred at lower doses (≥1 µM) than structural DNA damages (≥10 µM). Cytostatic effects depended on the Hg concentration, with delays during S-phase at lower doses, and arrests at G1 at higher ones. This arrest was paralleled with decreases of both mitotic index (MI) and cell proliferation index (CPI). DNA fragmentation, assessed by the Comet assay parameters of TD and TM, could be visualized for conditions ≥10 µM, while FCM-clastogenic parameter (FPCV) and micronuclei (MNC) were only altered in roots exposed to 100 µM. We demonstrate that inorganic-Hg induced cytostaticity is detectable even at 1 µM (a value found in contaminated sites), while structural DNA breaks/damage are only visualized in plants at concentrations ≥10 µM. We also demonstrate that among the different techniques tested for cyto- and genotoxicity, TD and TM Comet endpoints were more sensitive than FPCV or MNC. Regarding cytostatic effects, cell cycle analysis by FCM, including the difference in % cell cycle phases and CPI were more sensitive than MI or MNC frequency. Our data contribute to better understand Hg cyto- and genotoxicity in plants and to understand the information and sensitivity provided by each of the genotoxic techniques used.

Somatic embryogenesis in Carica papaya as affected by auxins and explants, and morphoanatomical-related aspects.

The aim of this study was to evaluate somatic embryogenesis in juvenile explants of the THB papaya cultivar. Apical shoots and cotyledonary leaves were inoculated in an induction medium composed of different concentrations of 2,4-D (6, 9, 12, 15 and 18 µM) or 4-CPA (19, 22, 25, 28 and 31 µM). The embryogenic calluses were transferred to a maturation medium for 30 days. Histological analysis were done during the induction and scanning electron microscopy after maturing. For both types of auxin, embryogenesis was achieved at higher frequencies with cotyledonary leaves incubated in induction medium than with apical shoots; except for callogenesis. The early-stage embryos (e.g., globular or heart-shape) predominated. Among the auxins, best results were observed in cotyledonary leaves induced with 4-CPA (25 µM). Histological analyses of the cotyledonary leaf-derived calluses confirmed that the somatic embryos (SEs) formed from parenchyma cells, predominantly differentiated via indirect and multicellular origin and infrequently via synchronized embryogenesis. The secondary embryogenesis was observed during induction and maturation phases in papaya THB cultivar. The combination of ABA (0.5 µM) and AC (15 g L-1) in maturation medium resulted in the highest somatic embryogenesis induction frequency (70 SEs callus-1) and the lowest percentage of early germination (4%).