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1.
Ecotoxicol Environ Saf ; 208: 111675, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33396007

RESUMO

Metal bioavailability controls its behaviors in soil-plant system, especially involved in biochar amendment. This study compared a rhizospheric pore-water extraction against a BCR sequential extraction method to understand cadmium (Cd) bioavailability in two typical Chinese soils. Soils were spiked with five levels of Cd (CdCl2) and remediated with 3% corn-straw derived biochar. After 60 days of lettuce growth, Cd accumulation and enzyme activities in tissues were analyzed. Results showed that biochar increased soil properties (pH, CEC and SOM) compared to un-amended soils, but decreased contents of bioavailable Cd in soil pore-water (Cdpore-water) and BCR extracted Cd (CdFi+Fii). Contents of Cdpore-water were lower in yellow-brown soils than that in red soils. Pearson analysis showed that bioavailable Cd is negatively correlated with soil pH and CEC (p < 0.05). Cd accumulation in lettuce roots and leaves both were decreased by biochar addition, and the established linear equations proved that soil Cdpore-water is the best predictor for Cd accumulation in lettuce roots (r2 = 0.964) and in leaves (r2 = 0.953), followed by CdFi+Fii. Transfer factor (TF) values of Cd from roots to leaves were lower than 1, and slightly better correlated with soil Cdpore-water (r = -0.674, p < 0.01) than CdFi+Fii (r = -0.615, p < 0.01). Aggregated boosted tree (ABT) analyses indicated that soil properties together with Cdpore-water contribute more than 50% to root enzyme activities. Collectively, soil Cdpore-water is a promising predictor of Cd bioavailability, accumulation and toxicity in soil-plant system with biochar addition.


Assuntos
Bioacumulação/efeitos dos fármacos , Cádmio/toxicidade , Carvão Vegetal/química , Alface/efeitos dos fármacos , Poluentes do Solo/toxicidade , Disponibilidade Biológica , Transporte Biológico , Cádmio/metabolismo , Alface/metabolismo , Modelos Teóricos , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/metabolismo , Caules de Planta/química , Rizosfera , Solo/química , Poluentes do Solo/metabolismo , Água/química , Zea mays/química
2.
Chemosphere ; 262: 127677, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32763571

RESUMO

Plant uptake of antibiotics raises serious food safety concerns. Measurements and predictions of antibiotic uptake by plants are often based on root concentration factors (RCF) determined using antibiotic concentrations in bulk soil (RCFbs) rather than in rhizosphere soil (RCFrs) where root uptake actually occurs. This study investigated the fate and transport of nine antibiotics in the continuum of bulk soil, rhizosphere soil, roots and shoots of lettuce (Lactuca sativa) under soil-surface irrigation. Antibiotic concentrations in the lettuce shoots remained unchanged during 25-35 days after seedling transplantation. Compared with the RCFrs values, the RCFbs values were significantly greater for ciprofloxacin, lincomycin, oxytetracycline, sulfamethoxazole, and tetracycline (p < 0.05), similar for trimethoprim and tylosin, but significantly lower for monensin (p < 0.05). Ciprofloxacin, trimethoprim, and tylosin had the lowest translocation factors (TF) ranging between 0.03 and 0.05, suggesting their limited upward transport to the lettuce shoots. Oxytetracycline, monensin, and sulfamethoxazole had intermediate TF values of 0.36-0.64, whereas lincomycin had the highest TF value of 1.46. This study showed significant differences between RCFbs and RCFrs values, suggesting the need to reassess the utility of RCFbs in predicting the antibiotic root uptake in diverse soil-plant systems.


Assuntos
Antibacterianos/metabolismo , Alface/metabolismo , Poluentes do Solo/metabolismo , Ciprofloxacino , Raízes de Plantas/química , Rizosfera , Solo , Poluentes do Solo/análise , Sulfametoxazol , Trimetoprima , Tilosina
3.
Chemosphere ; 262: 127612, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32750590

RESUMO

Widely used conazole fungicides (CFs) belong to the most frequently detected pesticides in Central European arable soils. However, data on their environmental behaviour and bioavailability to soil organisms are surprisingly scarce. In the present laboratory microcosm study prochloraz, tebuconazole, epoxiconazole and flusilazole were applied to 12 different agricultural soils at background levels. Bioaccumulation to earthworm E. andrei and lettuce L. sativa roots and leaves was evaluated in non-aged (biota exposure after addition of pesticides) and aged (exposure started three months later) systems. In contrast with expectations from ageing effect (decrease of bioavailability), bioaccumulation in E. andrei was both reduced and enhanced after ageing depending on soil properties. The reduction of bioaccumulation correlated positively to the percentage of clay but negatively to soil organic matter. The affinity of compost worm E. andrei towards organic matter where hydrophobic pesticide molecules are sorbed is discussed as a possible explanation. An apparent effect of ageing (reduction of bioavailability) was particularly observed in lettuce roots, where bioaccumulation was significantly reduced in time. However, bioaccumulation in leaves changed ambiguously in aged variants among CFs, possibly as a combined result of bioconcentration, dilution by plant growth and metabolism. This study brings first insights into how the bioaccumulation of conazole fungicides is affected by sequestration in agricultural soils. The results indicate that in complex systems, the ageing is not necessarily connected with decrease of bioaccumulation.


Assuntos
Fungicidas Industriais/metabolismo , Poluentes do Solo/metabolismo , Agricultura , Animais , Bioacumulação , Disponibilidade Biológica , Argila , Compostos de Epóxi , Fungicidas Industriais/análise , Alface/metabolismo , Oligoquetos/metabolismo , Praguicidas/análise , Silanos , Solo/química , Poluentes do Solo/análise , Triazóis
4.
Chemosphere ; 260: 127608, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32683016

RESUMO

This study explores whether mechanistic understanding of plant uptake of perfluoroalkyl acids (PFAAs) derived from hydroponic experiments can be applied to soil systems. Lettuces (Lactuca sativa) were grown in outdoor lysimeters in soil spiked with 4 different concentrations of 13 PFAAs. PFAA concentrations were measured in soil, soil pore water, lettuce roots, and foliage. The PFAA uptake by the lettuce was compared with uptake measured in a hydroponic study. The foliage:pore water concentration ratios in the lysimeter were similar to the foliage:water concentration ratios from the hydroponic experiment. In contrast, the root:pore water concentration ratios in the lysimeter were 1-2 orders of magnitude lower than in the hydroponic study for PFAAs with 6 or more perfluorinated carbons. Hence, hydroponic studies can be expected to provide a good quantitative measure of PFAA transfer from soil to foliage if one accounts for soil:pore water partitioning and differences in transpiration rate. However, hydroponic studies will be of little value for estimating PFAA transfer from soil to roots because sorption to the root surface is greatly enhanced under hydroponic conditions.


Assuntos
Fluorcarbonetos/metabolismo , Alface/metabolismo , Poluentes do Solo/metabolismo , Fluorcarbonetos/análise , Hidroponia , Solo , Poluentes do Solo/análise , Água
5.
Plant Physiol Biochem ; 151: 673-680, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32353673

RESUMO

This study was carried out to evaluate the effects of foliar sprays containing boron (B) nano-fertilizer (NF) on the growth and physiology of lettuce (Lactuca sativa) and zucchini (Cucurbita pepo). Plants were grown under greenhouse conditions for 60 days on a modified Hoagland solution with the presence and absence of boron (+B or -B). A synthesized B-NF foliar spray and a commercial B foliar fertilizer (Bortrac™ 150, BT) was applied at a concentration of 30 mg B L-1 at 10-d intervals throughout the experiment. The B-NF treatment increased the growth of lettuce 2.7- and 1.9-fold for shoots and roots, respectively, with an average production of lettuce biomass by ~58%. Similarly, the NF increased the growth of zucchini by 18 and 66% compared with Control-B (the absence of B), and 13 and 36% compared with BT, both for shoots and roots, respectively. Nevertheless, NF + B mostly decreased lettuce growth with symptoms of B toxicity in leaves. In lettuce, addition of B did not affect concentrations of phenols; however, in zucchini, Control-B induced a higher production of phenolic compounds possibly related to B deficiency. The B addition in lettuce reduced the DPPH activity by 32 and 21% in NF and BT, respectively, compared to Control-B. These responses were similar in zucchini; however, the effect of B was product of its presence in mineral solution rather than due the foliar product applied. This suggests that a NF-based delivery system for B may be highly effective at boosting plant productivity on B-limited soils.


Assuntos
Boratos , Compostos de Cálcio , Cucurbita , Fertilizantes , Alface , Nanopartículas , Boratos/química , Compostos de Cálcio/química , Cucurbita/metabolismo , Alface/metabolismo , Nanopartículas/química , Folhas de Planta/metabolismo , Raízes de Plantas/metabolismo
6.
Sci Rep ; 10(1): 5819, 2020 04 02.
Artigo em Inglês | MEDLINE | ID: mdl-32242034

RESUMO

Climatic change is pointed as one of the major challenges for global food security. Based on current models of climate change, reduction in precipitations and in turn, increase in the soil salinity will be a sharp constraint for crops productivity worldwide. In this context, root fungi appear as a new strategy to improve plant ecophysiological performance and crop yield under abiotic stress. In this study, we evaluated the impact of the two fungal endophytes Penicillium brevicompactum and P. chrysogenum isolated from Antarctic plants on nutrients and Na+ contents, net photosynthesis, water use efficiency, yield and survival in tomato and lettuce, facing salinity stress conditions. Inoculation of plant roots with fungal endophytes resulted in greater fresh and dry biomass production, and an enhanced survival rate under salt conditions. Inoculation of plants with the fungal endophytes was related with a higher up/down-regulation of ion homeostasis by enhanced expression of the NHX1 gene. The two endophytes diminished the effects of salt stress in tomato and lettuce, provoked a higher efficiency in photosynthetic energy production and an improved sequestration of Na+ in vacuoles is suggested by the upregulating of the expression of vacuolar NHX1 Na+/H+ antiporters. Promoting plant-beneficial interactions with root symbionts appears to be an environmentally friendly strategy to mitigate the impact of climate change variables on crop production.


Assuntos
Produtos Agrícolas/metabolismo , Produtos Agrícolas/fisiologia , Endófitos/fisiologia , Raízes de Plantas/metabolismo , Raízes de Plantas/fisiologia , Estresse Salino/fisiologia , Sódio/metabolismo , Regiões Antárticas , Biomassa , Mudança Climática , Produtos Agrícolas/microbiologia , Regulação para Baixo/fisiologia , Homeostase/fisiologia , Íons/metabolismo , Alface/metabolismo , Alface/microbiologia , Alface/fisiologia , Lycopersicon esculentum/metabolismo , Lycopersicon esculentum/microbiologia , Lycopersicon esculentum/fisiologia , Penicillium chrysogenum/fisiologia , Fotossíntese/fisiologia , Raízes de Plantas/microbiologia , Salinidade , Trocadores de Sódio-Hidrogênio/metabolismo , Solo , Estresse Fisiológico/fisiologia , Taxa de Sobrevida , Regulação para Cima/fisiologia , Água/metabolismo
7.
PLoS One ; 15(4): e0226471, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32348333

RESUMO

The chive maggot Bradysia cellarum and the fungus gnat B. impatiens are two primary root pests of plants, which can coexist on the same host plants and are the devastating pests on liliaceous crops and edible fungi. Their growth and development are affected by the nutrient contents of their host plants. In this study, we assessed the effects of different host plant nutrients on the nutrient contents of these two Bradysia species. The nutrients of the chive (Allium tuberosum Rottl. ex Spreng.), board bean (Vicia faba L.), lettuce (Lactuca sativa L. var. ramosa Hort.), cabbage (Brassica oleracea L.), wild cabbage (Brassica oleracea var. capitata rubra) and pepper (Capsicum annuum L.) roots were determined, and their effect on nutrient content of the two Bradysia species after feeding on the host plant for three continuous generations were evaluated. The results show that chive and B-bean contained higher levels of protein, free amino acid, soluble sugar and starch than others. As a result, the soluble sugar, fat and protein contents were significantly higher in both Bradysia species reared on chive and B-bean than on cabbage, lettuce, W-cabbage and pepper, suggesting nutritional preference of these insects. Based on our results, we concluded that the two Bradysia species displayed nutrient preference toward chive and B-bean, which provides a reference for understanding their host plant range and for control of the insect species via field crop rotations.


Assuntos
Produtos Agrícolas/metabolismo , Produtos Agrícolas/parasitologia , Dípteros/fisiologia , Interações Hospedeiro-Parasita , Nutrientes/metabolismo , Animais , Brassica/metabolismo , Brassica/parasitologia , Capsicum/metabolismo , Capsicum/parasitologia , Cebolinha-Francesa/metabolismo , Cebolinha-Francesa/parasitologia , Alface/metabolismo , Alface/parasitologia , Raízes de Plantas/metabolismo , Raízes de Plantas/parasitologia , Vicia faba/metabolismo , Vicia faba/parasitologia
8.
J Food Sci ; 85(5): 1605-1612, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32249421

RESUMO

Lettuce is one of the most popular vegetables, and the market niche of the baby leaf variety is expanding. The manner in which nitrogen (N) is supplied and the available concentration of the micronutrient molybdenum (Mo) affect N metabolism, with reflects on the nutritional quality of that vegetable. Here, two Mo concentrations (0.06 and 0.12 mg/L) and four proportions (%) of nitrate (NO3 - )/ammonium (NH4 + )(100/0, 75/25, 50/50, and 25/75) were supplied to hydroponic baby leaf lettuce floating type to evaluate their effects on plant growth and leaf mineral and NO3 - compositions. Shoot dry mass did not differ among the different treatments, although fresh mass was lower in treatments with larger proportions of NH4 + . Higher leaf concentrations of NO3 - were observed in plants treated with 100% N-NO3 - , but they were still below tolerable limits for human health. The enzyme nitrate reductase was not found to be sensitive to the nitrogen sources or to Mo concentrations. N proportions and Mo concentrations differently affected macro- (C, N, P, K, Ca, Mg, and S) and micronutrients (Cu, Fe, Mn, Mo, and Zn) leaf concentrations. Although treatment with 100% N-NO3 - favored higher mineral concentrations in lettuce leaves, the addition of 25% N-NH4 + allowed fresh mass production with the lowest NO3 - concentrations. As such, and considering the healthy reduction of NO3 - consumption by humans and the maintenance of plant productivity, the 75/25 NO3 - /NH4 + proportion is recommended for the hydroponic cultivation of baby leaf var. Mimosa lettuce. PRACTICAL APPLICATION: We demonstrate a direct link between the constitution of nutrient solution with nitrate accumulation by hydroponic lettuce and indicate the best source of N as well as the concentration of Mn to healthy reduction of NO3 - consumption by humans and the maintenance of plant productivity.


Assuntos
Alface/metabolismo , Molibdênio/metabolismo , Nitratos/análise , Folhas de Planta/química , Compostos de Amônio/análise , Compostos de Amônio/metabolismo , Humanos , Hidroponia , Alface/química , Alface/crescimento & desenvolvimento , Molibdênio/análise , Nitratos/metabolismo , Nitrogênio/análise , Nitrogênio/metabolismo , Valor Nutritivo , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Verduras/química , Verduras/crescimento & desenvolvimento , Verduras/metabolismo
9.
Food Chem ; 322: 126753, 2020 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-32283366

RESUMO

This paper investigated the effects of radio-frequency (RF) energy and conventional hot-water blanching (95 °C for 2 min) on the peroxidase (POD) activity, physiochemical properties, and changes in the cellular morphology of stem lettuce. The relative residual POD activity significantly decreased (P < 0.05) from 66.03% to 6.46% with increased RF heating temperature (65 °C-85 °C). The weight loss (3.06%-7.64%), color, texture, relative electrolyte leakage (23.45%-67.90%), and residual vitamin C content (72.22%-16.67%) significantly changed (P < 0.05) with increased RF heating temperature (65 °C-85 °C). Micrographs indicated that the changes in physiochemical property can be attributed to the destruction of cell membranes, loss of cell turgor, reduced rigidity of cell walls, and loose adhesion between adjacent cells. Samples treated by RF heating at 75 °C showed lesser cell damage and better nutrient retention than those treated by hot-water blanching at a similar level of POD inactivation.


Assuntos
Alface/metabolismo , Peroxidase/metabolismo , Ondas de Rádio , Ácido Ascórbico/análise , Parede Celular/química , Eletrólitos/metabolismo , Temperatura Alta , Alface/efeitos da radiação , Alface/ultraestrutura , Paladar , Água/química
10.
Sci Rep ; 10(1): 3737, 2020 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-32111947

RESUMO

Encapsulated bioactive agents applied to the Lactuca sativa L. present an innovative approach to stimulate the production of plant secondary metabolites increasing its nutritive value. Calcium and copper ions were encapsulated in biopolymeric microparticles (microspheres and microcapsules) either as single agents or in combination with biocontrol agents, Trichoderma viride spores, a fungal plant growth mediator. Both, calcium and copper ions are directly involved in the synthesis of plant secondary metabolites and alongside, Trichoderma viride can provide indirect stimulation and higher uptake of nutrients. All treatments with microparticles had a positive effect on the enhancement of plant secondary metabolites content in Lactuca sativa L. The highest increase of chlorophylls, antioxidant activity and phenolic was obtained by calcium-based microparticles in both, conventionally and hydroponically grown lettuces. Non-encapsulated fungus Trichoderma viride enhanced the synthesis of plant secondary metabolites only in hydroponics cultivation signifying the importance of its encapsulation. Encapsulation proved to be simple, sustainable and environmentally favorable for the production of lettuce with increased nutritional quality, which is lettuce fortified with important bioactive compounds.


Assuntos
Cálcio/farmacologia , Cobre/farmacologia , Alface , Doenças das Plantas/microbiologia , Folhas de Planta , Esporos Fúngicos/crescimento & desenvolvimento , Trichoderma/crescimento & desenvolvimento , Cápsulas , Alface/metabolismo , Alface/microbiologia , Folhas de Planta/metabolismo , Folhas de Planta/microbiologia
11.
Bull Environ Contam Toxicol ; 104(4): 444-448, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32152686

RESUMO

Urban horticulture and community gardening have become more and more popular in the past years, however, the risk of bioaccumulation of atmospheric polyaromatic hydrocarbons (PAHs) in vegetables grown in polluted areas cannot be neglected. In our study, the No. 227 OECD GUIDELINE FOR THE TESTING OF CHEMICALS: Terrestrial Plant Test: Vegetative Vigour Test was followed to assess foliar uptake of PAHs from aqueous extract of an urban aerosol. Using lettuce (Lactuca sativa) as a test organism, significant accumulation was experienced. The highest bioconcentration factors (BCFs) were experienced for naphthalene and for anthracene, pyrene and fluoranthene showed the lowest bioaccumulation potential. BCF of each PAH showed strong correlation with molecular weight. The standard protocol defined by the Guideline made it possible to assess bioaccumulation pattern under controlled laboratory conditions.


Assuntos
Poluentes Atmosféricos/análise , Bioacumulação , Monitoramento Biológico/métodos , Alface/química , Hidrocarbonetos Policíclicos Aromáticos/análise , Aerossóis , Poluentes Atmosféricos/metabolismo , Alface/metabolismo , Modelos Teóricos , Folhas de Planta/química , Folhas de Planta/metabolismo , Hidrocarbonetos Policíclicos Aromáticos/metabolismo
12.
Int J Mol Sci ; 21(4)2020 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-32098243

RESUMO

Temperature strongly influences lettuce (Lactuca sativa L.) seed germination. Different lettuce genotypes respond differently to higher temperatures or thermal stress. In this study, we evaluated the germination performance of 304 lettuce accessions incubated at three temperature settings, 21 °C, 28 °C and 35 °C, respectively, for 40 h. At 21 °C, seeds of all 304 accessions germinated with very well an average germination percentage of 87.72%; at 28 °C, the average germination percentage dropped to 42.84% and at 35 °C, the germination decreased to 1.01%. Then, we investigated changes in metabolic profiles of lettuce seed response to thermal stress using an untargeted metabolomics approach. Results suggested that seeds of thermal-sensitive and thermal-tolerant cultivars employed different metabolic strategies in response to thermal stress during germination. Thermal-sensitive buds accumulated more significant amounts of organic acids, amino acids, sugars, sterols, phenolic compounds and terpenoids compared to thermal-tolerant buds at 21 °C. Thermal-tolerant lettuce cultivar accumulated higher concentrations of amino acids, organic acids, sugars, sesquiterpene lactones, sterols, and fatty acids derivatives during the germination at 35 °C compared to germinated at 21 °C. This investigation paves the way to link the metabolomics to other external and internal factors affecting lettuce seed germination under thermal stress.


Assuntos
Germinação , Resposta ao Choque Térmico , Alface/metabolismo , Metaboloma , Sementes/metabolismo , Temperatura Alta
13.
Environ Pollut ; 260: 114002, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31991361

RESUMO

Antibiotics can be uptaken by plants from soil desorption or directly from irrigation water, but their metabolization pathways in plants are largely unknown. In this paper, an analytical workflow based on high-resolution mass spectrometry was applied for the systematic identification of biotransformation products of ofloxacin in lettuce. The targeted metabolites were selected by comparing the mass chromatograms of exposed with control samples using an advanced spectra-processing method (Fragment Ion Search). The innovative methodology presented allowed us to identify a total of 11 metabolites, including 5 ofloxacin metabolites that are being reported for the first time in plants. Accordingly, major transformation pathways were proposed revealing insight into how ofloxacin and related chemicals are metabolized in lettuce. Furthermore, the influence of biotransformation on potential residual antimicrobial activity of identified compounds was discussed. Human exposure to antibiotics at doses below the minimum inhibitory concentrations is crucial in human risk assessment, including food ingestion; however, in the case of ofloxacin presented results reveal that plant metabolites should also be considered so as not to underestimate their risk.


Assuntos
Alface/metabolismo , Ofloxacino/metabolismo , Antibacterianos/metabolismo , Biotransformação , Humanos
14.
Environ Sci Pollut Res Int ; 27(8): 8707-8718, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31912394

RESUMO

Excess Cd and Pb in agricultural soils enter the food chain and adversely affect all organisms. Therefore, it is important to find an eco-friendly way to reduce heavy metal accumulation in vegetables. We used urea agar plates to isolate urease-producing bacteria from the rhizosphere soil of lettuce in Cd- and Pb-contaminated farmland and investigated their ability to produce urease and immobilize heavy metals. The effects of these strains on the biomass, quality, and Cd and Pb accumulation of lettuce were also studied. The results showed that two urease-producing bacteria, Enterobacter bugandensis TJ6 and Bacillus megaterium HD8, were screened from the rhizosphere soil of lettuce. They had a high ability to produce urease (44.5 mS cm-1 min-1 OD600-1 and 54.2 mS cm-1 min-1 OD600-1, respectively) and IAA (303 mg L-1 and 387 mg L-1, respectively). Compared with the control, inoculation with strains TJ6 and HD8 reduced the Cd (75.3-85.8%) and Pb (74.8-87.2%) concentrations and increased the pH (from 6.92 to 8.13-8.53) in solution. A hydroponic experiment showed that the two strains increased the biomass (31.3-55.2%), improved the quality (28.6-52.6% for the soluble protein content and 34.8-88.4% for the vitamin C (Vc) content), and reduced the Cd (25.6-68.9%) and Pb (48.7-78.8%) contents of lettuce shoots (edible tissue). In addition, strain HD8 had a greater ability than strain TJ6 to reduce lettuce Cd and Pb uptake and water-soluble Cd and Pb levels in solution. These data show that the urease-producing bacteria protect lettuce against Cd and Pb toxicity by extracellular adsorption, Cd and Pb immobilization, and increased pH. The effects of heavy metal immobilization by the two strains can guarantee vegetable safety in situ for the bioremediation of heavy metal-polluted farmland.


Assuntos
Bactérias/metabolismo , Cádmio/metabolismo , Chumbo/metabolismo , Alface/metabolismo , Metais Pesados , Poluentes do Solo , Urease/metabolismo , Bactérias/isolamento & purificação , Alface/microbiologia , Solo , Microbiologia do Solo
15.
Plant Biotechnol J ; 18(2): 479-490, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31325407

RESUMO

Anthocyanins protect plants from biotic and abiotic stressors and provide great health benefits to consumers. In this study, we cloned four genes (Red Lettuce Leaves 1 to 4: RLL1 to RLL4) that contribute to colour variations in lettuce. The RLL1 gene encodes a bHLH transcription factor, and a 5-bp deletion in some cultivars abolishes its function to activate the anthocyanin biosynthesis pathway. The RLL2 gene encodes an R2R3-MYB transcription factor, which was derived from a duplication followed by mutations in its promoter region. The RLL3 gene encodes an R2-MYB transcription factor, which down-regulates anthocyanin biosynthesis through competing with RLL2 for interaction with RLL1; a mis-sense mutation compromises the capacity of RLL3 to bind RLL1. The RLL4 gene encodes a WD-40 transcription factor, homologous to the RUP genes suppressing the UV-B signal transduction pathway in Arabidopsis; a mis-sense mutation in rll4 attenuates its suppressing function, leading to a high concentration of anthocyanins. Sequence analysis of the RLL1-RLL4 genes from wild and cultivated lettuce showed that their function-changing mutations occurred after domestication. The mutations in rll1 disrupt anthocyanin biosynthesis, while the mutations in RLL2, rll3 and rll4 activate anthocyanin biosynthesis, showing disruptive selection for leaf colour during domestication of lettuce. The characterization of multiple polymorphic genes in this study provides the necessary molecular resources for the rational breeding of lettuce cultivars with distinct levels of red pigments and green cultivars with high levels of health-promoting flavonoids.


Assuntos
Antocianinas , Domesticação , Alface , Pigmentação , Folhas de Planta , Antocianinas/genética , Regulação da Expressão Gênica de Plantas , Alface/genética , Alface/metabolismo , Pigmentação/genética , Folhas de Planta/genética , Folhas de Planta/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas , Seleção Genética
16.
Food Chem ; 308: 125443, 2020 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-31654979

RESUMO

Amongst green leafy vegetables, new varieties of lettuce enriched in lutein and ß-carotene are being developed to provide increased supply of dietary carotenoids. We investigated the effect of lettuce genotypes (varieties) and thermal treatments on lutein and ß-carotene bioaccessibility to the micellar fraction (and also carotenoid bioavailability) using a human Caco-2 cell model system. Carotenoid absorption by mammalian cells is not correlated with initial carotenoid concentration in fresh lettuce leaves. While thermal treatment of lettuce leaves increases carotenoid availability, resulting in higher lutein and ß-carotene absorption, disruption of the food matrix by prior cooking results in reduced carotenoid levels and transfer to the micellar fraction. Unless the food matrix is disrupted through breeding or post-harvest treatments, absorption of carotenoids from biofortified lettuce remains similar to lettuce cultivars with low carotenoid levels. Genetic improvement programs for biofortified lettuce varieties need to focus on increasing the carotenoid bioavailability from the food matrix.


Assuntos
Alimentos Fortificados , Alface/metabolismo , Luteína/metabolismo , beta Caroteno/metabolismo , Disponibilidade Biológica , Células CACO-2 , Culinária/métodos , Humanos , Verduras/metabolismo
17.
Food Chem Toxicol ; 135: 110939, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31697969

RESUMO

The effects of foliar Se biofortification (Se+) of the lettuce on the transfer and toxicity of Hg from soil contaminated with HgCl2 (H) and soil collected near the former Hg smelter in Idrija (I), to terrestrial food chain are explored, with Spanish slug as a primary consumer. Foliar application of Se significantly increased Se content in the lettuce, with no detected toxic effects. Mercury exerted toxic effects on plants, decreasing plant biomass, photochemical efficiency of the photosystem II (Fv/Fm) and the total chlorophyll content. Selenium biofortification (Se+ test group) had no effect on Hg bioaccumulation in plants. In slugs, different responses were observed in H and I groups; the I/Se+ subgroup was the most strongly affected by Hg toxicity, exhibiting lower biomass, feeding and growth rate and a higher hepatopancreas/ muscle Hg translocation, pointing to a higher Hg mobility in comparison to H group. Selenium increased Hg bioavailability for slugs, but with opposite physiological responses: alleviating stress in H/Se+ and inducing it in I/Se+ group, indicating different mechanisms of Hg-Se interactions in the food chain under HgCl2 and Idrija soil exposures that can be mainly attributed to different Hg speciation and ligand environment in the soil.


Assuntos
Biofortificação/métodos , Cadeia Alimentar , Gastrópodes/metabolismo , Alface/metabolismo , Mercúrio/toxicidade , Selênio/farmacologia , Animais , Bioacumulação , Disponibilidade Biológica , Poluentes Ambientais/farmacocinética , Poluentes Ambientais/toxicidade , Cloreto de Mercúrio/farmacocinética , Cloreto de Mercúrio/toxicidade , Mercúrio/farmacocinética , Solo/química
18.
J Agric Food Chem ; 68(5): 1207-1212, 2020 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-31755264

RESUMO

Human noroviruses (HuNoVs) are among the main pathogens causing acute nonbacterial gastroenteritis. Histo-blood group antigens (HBGAs) are widely accepted receptors for HuNoV specific binding. HBGA-like substances in produce are also considered as the critical ligands for capture of HuNoVs. However, the composition of viral ligands from food substrates remains unknown. In this study, an oligosaccharide (H2N2F2) was captured and isolated from romaine lettuce extract by a bacterial surface display system. Using electrospray ionization mass spectrometry and tandem mass spectrometry, it was shown that H2N2F2 was most likely to be a chimera of type A, H, and Lewis a HBGAs. The composition was consistent with our ELISA results using a panel of monoclonal antibodies against HBGAs. Our results revealed a possible interaction mechanism between HuNoVs and romaine lettuce. Better understanding of the interaction of HuNoVs with easily contaminated produce will ultimately aid in the control of and reduction in disease outbreaks.


Assuntos
Antígenos de Plantas/metabolismo , Antígenos de Grupos Sanguíneos/metabolismo , Alface/virologia , Norovirus/fisiologia , Receptores Virais/metabolismo , Ligação Viral , Antígenos de Plantas/química , Antígenos de Plantas/genética , Antígenos de Grupos Sanguíneos/química , Antígenos de Grupos Sanguíneos/genética , Infecções por Caliciviridae/genética , Infecções por Caliciviridae/metabolismo , Infecções por Caliciviridae/virologia , Humanos , Alface/química , Alface/genética , Alface/metabolismo , Espectrometria de Massas , Norovirus/genética , Oligossacarídeos/química , Oligossacarídeos/genética , Oligossacarídeos/metabolismo , Ligação Proteica , Receptores Virais/química , Receptores Virais/genética
19.
Food Chem ; 311: 125885, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-31780224

RESUMO

In this study, the potential health benefits of crisphead lettuce (Lactuca sativa L.) before and after digestion were represented by the recovery, bioaccessibility, and change of bioactive compounds including total phenolic (TPC) and total flavonoids content (TFC), and bioactivities [in vitro antioxidant activities including 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2, 2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activities, ferric reducing antioxidant power (FRAP) and metal ion chelating activity (MIC)]. The release of bioactive compounds as well as bioactivities increased during gastric and intestinal digestion for 1 h and subsequently decreased when digestion was completed. The bioaccessibility of TPC and TFC at after digestion was 56-73 and 75-79%, respectively. Among all bioactivities, crisphead lettuce showed a residual activity of ABTS (61-95%) followed by FRAP (70-86%), DPPH (24-52%) and MIC (32-73%) during the digestion. Our study suggested that crisphead lettuce maintains stability in both bioactive compounds and bioactivities during the digestion.


Assuntos
Antioxidantes/química , Alface/metabolismo , Flavonoides/análise , Flavonoides/química , Alface/química , Pepsina A/metabolismo , Fenóis/análise , Fenóis/química , Espectrofotometria
20.
Nanoscale ; 12(1): 155-166, 2020 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-31799548

RESUMO

Maximizing the utilization of the ultraviolet portion in the solar radiation spectrum has always been a goal for plant growth in order to minimize the harm and harvest the benefits. For this reason, fluorescent, amine-functionalized, and water-soluble silicon quantum dots (SiQDs) were fabricated with a mono-dispersed size of 2.4 nm. The SiQDs were used as artificial antennas to amplify the light harvesting ability and consequently enhance the photosynthesis in Italian lettuce. Upon ultraviolet excitation, the intense blue emission from the quantum dots matched very well to the absorption of the chloroplasts, allowing for the ultraviolet portion in solar radiation to be effectively utilized. The consumed optical energy enhanced the photosystem II activity, which made the amplification of photosynthesis possible. More importantly, in vivo, the quantum dots significantly promoted Italian lettuce seedling growth at concentrations below 30 mg L-1 on the root length, seedling height, and biomass by increasing the soluble sugar and water content by 49.8% and 40.9%, respectively. Interestingly, the chlorophyll a and b content increased to 41.0 and 114.8%, respectively, with no inhibition, even at the highest dose of 200 mg L-1. This study provides a new perspective on the use of quantum dots to amplify the utilization of ultraviolet light in agriculture.


Assuntos
Alface/metabolismo , Pontos Quânticos/química , Silício/química , Raios Ultravioleta , Clorofila A/química , Cloroplastos/metabolismo , Alface/crescimento & desenvolvimento , Fotossíntese/efeitos da radiação , Complexo de Proteína do Fotossistema II/química , Complexo de Proteína do Fotossistema II/metabolismo , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Plântula/efeitos da radiação , Estresse Fisiológico , Água/química
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