Lutein Activates the Transcription Factor <i>Nrf2</i> in Human Retinal Pigment Epithelial Cells

The degeneration of the retinal pigment epithelium caused by oxidative damage is a stage of development in age-related macular degeneration (AMD). The carotenoid lutein is a major macular pigment that may reduce the incidence and progression of AMD, but the underlying mechanism is currently not fully understood. Carotenoids are known to be direct antioxidants. However, carotenoids can also activate cellular pathways resulting in indirect antioxidant effects. Here, we investigate the influence of lutein on the activation of nuclear factor erythroid 2-related factor 2 (<i>Nrf2</i>) target genes in human retinal pigment epithelial cells (ARPE-19 cells) using lutein-loaded Tween40 micelles. The micelles were identified as a suitable delivery system since they were nontoxic in APRE-19 cells up to 0.04% Tween40 and led to a cellular lutein accumulation of 62 μM ± 14 μM after 24 h. Lutein significantly enhanced <i>Nrf2</i> translocation to the nucleus 1.5 ± 0.4-fold compared to that of unloaded micelles after 4 h. Furthermore, lutein treatment for 24 h significantly increased the transcripts of NAD­(P)­H:quinone oxidoreductase 1 (<i>NQO1</i>) by 1.7 ± 0.1-fold, glutamate-cysteine ligase regulatory subunit (<i>GCLm</i>) by 1.4 ± 0.1-fold, and heme oxygenase-1 (<i>HO-1</i>) by 1.8 ± 0.3-fold. Moreover, we observed a significant enhancement of NQO1 activity by 1.2 ± 0.1-fold. Collectively, this study indicates that lutein not only serves as a direct antioxidant but also activates <i>Nrf2</i> in ARPE-19 cells

Effects of Developmental Stages and Reduced UVB and Low UV Conditions on Plant Secondary Metabolite Profiles in Pak Choi (Brassica rapa subsp. <i>chinensis</i>)

Pak choi (Brassica rapa subsp. <i>chinensis</i>) is rich in secondary metabolites and contains numerous antioxidants, including flavonoids; hydroxycinnamic acids; carotenoids; chlorophylls; and glucosinolates, which can be hydrolyzed to epithionitriles, nitriles, or isothiocyanates. Here, we investigate the effect of reduced exposure to ultraviolet B (UVB) and UV (UVA and UVB) light at four different developmental stages of pak choi. We found that both the plant morphology and secondary metabolite profiles were affected by reduced exposure to UVB and UV, depending on the plant’s developmental stage. In detail, mature 15- and 30-leaf plants had higher concentrations of flavonoids, hydroxycinnamic acids, carotenoids, and chlorophylls, whereas sprouts contained high concentrations of glucosinolates and their hydrolysis products. Dry weights and leaf areas increased as a result of reduced UVB and low UV. For the flavonoids and hydroxycinnamic acids in 30-leaf plants, less complex compounds were favored, for example, sinapic acid acylated kaempferol triglycoside instead of the corresponding tetraglycoside. Moreover, also in 30-leaf plants, zeaxanthin, a carotenoid linked to protection during photosynthesis, was increased under low UV conditions. Interestingly, most glucosinolates were not affected by reduced UVB and low UV conditions. However, this study underlines the importance of 4-(methylsulfinyl)­butyl glucosinolate in response to UVA and UVB exposure. Further, reduced UVB and low UV conditions resulted in higher concentrations of glucosinolate-derived nitriles. In conclusion, exposure to low doses of UVB and UV from the early to late developmental stages did not result in overall lower concentrations of plant secondary metabolites

Nitrogen Limited Red and Green Leaf Lettuce Accumulate Flavonoid Glycosides, Caffeic Acid Derivatives, and Sucrose while Losing Chlorophylls, Β-Carotene and Xanthophylls

<div><p>Reduction of nitrogen application in crop production is desirable for ecological and health-related reasons. Interestingly, nitrogen deficiency can lead to enhanced concentrations of polyphenols in plants. The reason for this is still under discussion. The plants’ response to low nitrogen concentration can interact with other factors, for example radiation intensity. We cultivated red and green leaf lettuce hydroponically in a Mediterranean greenhouse, supplying three different levels of nitrogen (12 mM, 3 mM, 0.75 mM), either in full or reduced (-50%) radiation intensity. In both red and green lettuce, we found clear effects of the nitrogen treatments on growth characteristics, phenolic and photosynthetic compounds, nitrogen, nitrate and carbon concentration of the plants. Interestingly, the concentrations of all main flavonoid glycosides, caffeic acid derivatives, and sucrose increased with decreasing nitrogen concentration, whereas those of chlorophylls, β-carotene, neoxanthin, lactucaxanthin, <i>all trans</i>- and <i>cis</i>-violaxanthin decreased. The constitutive concentrations of polyphenols were lower in the green cultivar, but their relative increase was more pronounced than in the red cultivar. The constitutive concentrations of chlorophylls, β-carotene, neoxanthin, <i>all trans</i>- and <i>cis</i>-violaxanthin were similar in red and green lettuce and with decreasing nitrogen concentration they declined to a similar extent in both cultivars. We only detected little influence of the radiation treatments, e.g. on anthocyanin concentration, and hardly any interaction between radiation and nitrogen concentration. Our results imply a greater physiological plasticity of green compared to the red lettuce regarding its phenolic compounds. They support the photoprotection theory regarding anthocyanins as well as the theory that the deamination activity of phenylalanine ammonia-lyase drives phenylpropanoid synthesis.</p></div

Synthesis and Characterization of Quantum Dot Nanoparticles Bound to the Plant Volatile Precursor of Hydroxy-apo-10′-carotenal

This study is focused on the synthesis and characterization of hydroxy-apo-10′-carotenal/quantum dot (QD) conjugates aiming at the <i>in vivo</i> visualization of β-ionone, a carotenoid-derived volatile compound known for its important contribution to the flavor and aroma of many fruits, vegetables, and plants. The synthesis of nanoparticles bound to plant volatile precursors was achieved via coupling reaction of the QD to C₂₇-aldehyde which was prepared from α-ionone via 12 steps in 2.4% overall yield. The formation of the QD-conjugate was confirmed by measuring its fluorescence spectrum to observe the occurrence of fluorescence resonance energy transfer

Concentrations of carotenoids in red and green lettuce cultivated at different nitrogen concentration and photosynthetic photon flux density.

<p>Nitrogen (N) concentration in the nutrient solution is given in millimol per liter (mM). Photosynthetic photon flux density (PPFD) is given in μmol m⁻² s⁻¹. Concentrations are given in milligram per gram dry matter. Data was evaluated via two-way ANOVA, factors: mM N and PPFD, α = 0.05, followed by Tukey HSD test (mean, n = 3). Identical letters indicate that values do not differ significantly. Asterisks indicate significantly influential factors.</p><p>Concentrations of carotenoids in red and green lettuce cultivated at different nitrogen concentration and photosynthetic photon flux density.</p

Table_1_Composite materials for innovative urban farming of alternative food sources (macroalgae and crickets).doc

Facing an inexorable growth of the human population along with substantial environmental changes, the assurance of food security is a major challenge of the present century. To ensure responsible food consumption and production (SDG 12), new approaches in the food system are required. Thus, environmentally controlled, sustainable production of alternative food sources are of key interest for both urban agriculture and food research. To face the current challenge of integrating food production systems within existing structures, multidisciplinary discourses are required. Here, we bring together novel technologies and indoor farming techniques with the aim of supporting the development of sustainable food production systems. For this purpose, we investigated the feasibility of 10 composite materials for their innovative use as structural support in macroalgal cultivation (settlement substrates) and cricket rearing (housing). Considering material resistance, rigidity, and direct material-organism interactions, the bio-based composite polylactic acid (PLA) was identified as a suitable material for joint farming. For macroalgae cultivation, PLA sustained the corrosive cultivation conditions and provided a suitable substrate without affecting the macroalgal physiology or nutritional composition (carotenoids and chlorophylls). For cricket rearing, PLA provided a suitable and recyclable shelter, which was quickly accepted by the animals without any observed harm. In contrast, other common composite components like phenolic resin or aramid were found to be unsuitable due to being harmful for the cultivated organisms or instable toward the applied sterilization procedure. This multidisciplinary study not only provides profound insights in the developing field of urban indoor food production from a new perspective, but also bridges material science and farming approaches to develop new sustainable and resilient food production systems.</p

Concentrations of sugars in red and green lettuce cultivated at different nitrogen concentration and photosynthetic photon flux density.

<p>Nitrogen (N) concentration in the nutrient solution is given in millimol per liter (mM). Photosynthetic photon flux density (PPFD) is given in μmol m⁻² s⁻¹. Concentrations are given in milligram per gram dry matter. Data was evaluated via two-way ANOVA, factors: mM N and PPFD, α = 0.05, followed by Tukey HSD test (mean, n = 3). Identical letters indicate that values do not differ significantly. Asterisks indicate significantly influential factors.</p><p>Concentrations of sugars in red and green lettuce cultivated at different nitrogen concentration and photosynthetic photon flux density.</p

Concentrations of phenolic compounds, percent of total N invested in chlorophylls and percent of total N attributable to PAL activity in red and green lettuce cultivated at different nitrogen concentration and photosynthetic photon flux density.

<p>Nitrogen (N) concentration in the nutrient solution is given in millimol per liter (mM). Photosynthetic photon flux density (PPFD) is given in μmol m⁻² s⁻¹. Phenolics concentration is given in milligram per gram dry matter. Data was evaluated via two-way ANOVA, factors: mM N and PPFD, α = 0.05, followed by Tukey HSD test (mean, n = 3). Identical letters indicate that values do not differ significantly. Asterisks indicate significantly influential factors. Cy3MG = cyanidin-3-O-(6΄΄-O-malonyl)-glucoside, Q3MG = quercetin-3-O-(6΄΄-O-malonyl)-glucoside, Q3Gc/L7Gc = quercetin-3-O-glucuronide and luteolin-7-O-glucuronide.</p><p>Concentrations of phenolic compounds, percent of total N invested in chlorophylls and percent of total N attributable to PAL activity in red and green lettuce cultivated at different nitrogen concentration and photosynthetic photon flux density.</p

Data_Sheet_1_Composite materials for innovative urban farming of alternative food sources (macroalgae and crickets).doc

Facing an inexorable growth of the human population along with substantial environmental changes, the assurance of food security is a major challenge of the present century. To ensure responsible food consumption and production (SDG 12), new approaches in the food system are required. Thus, environmentally controlled, sustainable production of alternative food sources are of key interest for both urban agriculture and food research. To face the current challenge of integrating food production systems within existing structures, multidisciplinary discourses are required. Here, we bring together novel technologies and indoor farming techniques with the aim of supporting the development of sustainable food production systems. For this purpose, we investigated the feasibility of 10 composite materials for their innovative use as structural support in macroalgal cultivation (settlement substrates) and cricket rearing (housing). Considering material resistance, rigidity, and direct material-organism interactions, the bio-based composite polylactic acid (PLA) was identified as a suitable material for joint farming. For macroalgae cultivation, PLA sustained the corrosive cultivation conditions and provided a suitable substrate without affecting the macroalgal physiology or nutritional composition (carotenoids and chlorophylls). For cricket rearing, PLA provided a suitable and recyclable shelter, which was quickly accepted by the animals without any observed harm. In contrast, other common composite components like phenolic resin or aramid were found to be unsuitable due to being harmful for the cultivated organisms or instable toward the applied sterilization procedure. This multidisciplinary study not only provides profound insights in the developing field of urban indoor food production from a new perspective, but also bridges material science and farming approaches to develop new sustainable and resilient food production systems.</p

Growth characteristics and nitrogen, carbon and nitrate concentration of red and green lettuce cultivated at different nitrogen concentration and photosynthetic photon flux density.

<p>Nitrogen (N) concentration in the nutrient solution is given in millimol per liter (mM). Photosynthetic photon flux density (PPFD) is given in μmol m⁻² s⁻¹. Head mass is given in gram fresh matter. Nitrogen, carbon (C) and nitrate (NO₃) concentration is given in milligram per gram dry matter. Data was evaluated via two-way ANOVA, factors: mM N and PPFD, α = 0,05, followed by Tukey HSD test (mean, n = 3). Identical letters indicate that values do not differ significantly. Asterisks indicate significantly influential factors.</p><p>Growth characteristics and nitrogen, carbon and nitrate concentration of red and green lettuce cultivated at different nitrogen concentration and photosynthetic photon flux density.</p