A Dunaliella salina Extract Counteracts Skin Aging under Intense Solar Irradiation Thanks to Its Antiglycation and Anti-Inflammatory Properties

Glycation, and the resulting buildup of advanced glycation end products (AGEs), is recognized as a key driver of cumulative skin damage and skin aging. Dunaliella salina is a halophile microalga adapted to intense solar radiation through the production of carotenoids. We present a natural supercritical CO₂ extract of Dunaliella salina rich in the colorless carotenoids phytoene and phytofluene. The extract exhibited antiglycation and anti-inflammatory activities in ex vivo testing, showing strongly reduced formation of N-ε-carboxy-methyl-lysine with exposure to methylglyoxal, reduced AGE receptor levels, and significantly reduced interleukins 6 and 8. In a placebo-controlled clinical study under intense solar exposure, the extract significantly reduced the skin’s glycation scores and its sensitivity to histamine; key skin aging parameters were also significantly improved vs. placebo, including wrinkle counts and spots. These results demonstrate the value of this Dunaliella salina extract, rich in colorless carotenoids, as an antiglycative, anti-inflammatory, and antiaging active ingredient, including in high-irradiation contexts.     

Prior Inoculation with Non-pathogenic Fungi Induces Systemic Resistance to Powdery Mildew On Cucumber Plants

A spray inoculation of the first leaf of 2-leaf stage cucumber plants with a non-pathogenic isolate of Alternaria cucumarina or Cladosporium fulvum before a challenge inoculation with the pathogen Sphaerotheca fuliginea induced systemic resistance to powdery mildew on leaves 2–5. Systemic resistance was expressed by a significant (p < 0.05) reduction in the number of powdery mildew colonies produced on each leaf of the induced plants, as compared with water-sprayed plants. Systemic resistance was evident when a prior inoculation with each of the inducing fungi was administered 1, 3 or 6 days before the challenge inoculation with S. fuliginea. Increasing the inoculum concentration of A. cucumarina or C. fulvum enhanced the systemic protection and provided up to 71.6% or 80.0% reduction, respectively, in the number of colonies produced on upper leaves, relative to controls. Increasing the inoculum concentration of S. fuliginea used for challenge inoculation, increased the number of powdery mildew colonies produced on both induced and non-induced plants. Pre-treated plants, however, were still better protected than controls, indicating that the level of systemic protection was related to the S. fuliginea inoculum concentration. The induction of systemic resistance against powdery mildew by biotic agents, facilitates the development of a wide range of disease management tools.     

Compensation for seasonal changes in eggshell conductance and hatchability of goose eggs by dynamic control of egg water loss

1. The water loss for optimal hatchability of goose eggs was 12% of initial egg mass.

2. Mass specific eggshell water vapour conductance, G_sp, increased by approximately 50% over about 13 weeks during the winter breeding cycle. A similar increase occurred over 8 weeks during summer.

3. Constant setting of humidity in goose incubators and changes in mean G_sp may cause sub‐optimal egg water loss which increases late mortality.

4. Mean G_sp was measured for every batch from each flock. Humidity was changed accordingly in order to reach optimal water loss. A significant improvement of 6% in hatchability and of 8% in Class‐A goslings was noted during 14 successive weeks compared with the previous 11 weeks.

5. Dynamic humidity control for optimising water loss according to mean batch G_sp thus increases hatchability.     

A foliar spray of micronutrient solutions induces local and systemic protection against powdery mildew (Sphaerotheca fuliginia) in cucumber plants

A single spray of solutions of 0.005M H₃BO₃, 0.0025M CuSO₄, and 0.0025 MnCl₂, on the upper surface of the first true leaf of cucumber plants 2 h before inoculation with a conidial suspension of Sphaerotheca fuliginea, induced systemic protection against powdery mildew in leaves 2 and 3 without causing any damage on the induced leaf (first leaf). A similar level of systemic protection was observed when plants were induced by micronutrients, 2, 24 and 72 h before challenge with S. fuliginea. The level of protection induced by various concentrations varied from solution to solution. In general, the systemic protection induced by K₂HPO₄ was similar to that by the microelements. Spraying of a 1:1 mixture of phosphate and micronutrient solutions did not improve the systemic protection over that obtained with each of the solutions alone. Increasing the inoculum concentration of S. fuliginea increased the number of powdery mildew colonies produced on both induced and non-induced plants and has relatively affected the systemic protection on induced plants. A single foliar spray of micronutrient solutions, as a prophylactic treatment, on the upper surface of all the leaves of 3-leaf stage cucumber plants significantly inhibited powdery mildew development. A single spray of MnCl₂ on leaf 1 elevated peroxidase activity in the soluble fraction and caused an enhancement of -1,3-glucanase content in the ionically bound fractions of leaf 2 of non-inoculated plants. Forty-eight hours after inoculation, the level of both fractions of the enzymes increased in non-treated plants and decreased (-1,3-glucanase) or remained unchanged (peroxidase) in treated (induced) plants as compared to non-treated plants. The possible mechanism for this protection, and the use of microelements and phosphate solutions as inducers for systemic protection and as agents for disease control are discussed.     

Local and Systemic Activity of BABA (DL-3-aminobutyric Acid) Against Plasmopara viticola in Grapevines

The non-protein amino acid BABA (DL-3-amino-n-butanoic acid, -aminobutyric acid) is reported here to induce local and systemic resistance against downy mildew in grape leaves. Leaf discs of susceptible cultivars placed on BABA solutions and inoculated with Plasmopara viticola on the counter surface produced brownish restricted lesions below the inoculation site (Hypersensitive-like response, HR) which failed to support fungal sporulation. Histochemical analyses of such HR lesions revealed the accumulation of lignin-like deposits in the host cells. In contrast, water-treated inoculated discs produced expanded chlorotic lesions with profuse sporulation in which no lignin accumulation was observed. Mock-inoculated BABA-treated leaf discs showed no HR or lignin accumulation. Concentrations as low as 25µg/ml (0.25mM) of BABA sufficed to prevent tissue colonization with the fungus. Five other isomers of aminobutyric acid, namely L-2 aminobutyric acid, 2-amino isobutyric acid, DL-2-aminobutyric acid (AABA), DL-3-amino isobutyric acid, and 4-aminobutyric acid (GABA) gave no protection against the downy mildew fungus. Of the two (R and S) enantiomers of BABA only the R form was active in producing HR, suggesting a specific stereostructure requirement for activity. BABA could stop fungal colonization even when applied post-infectionally to leaf discs. Resistance of BABA-pulse-loaded leaf discs persisted for more than 14 days. BABA provided systemic protection against the disease when applied via the root system or via the lower leaves of grape plants. Application of ¹⁴C-BABA to a single leaf of intact plants showed the accumulation of the ¹⁴C label in upper leaves (and root tips), suggesting sink-oriented transport.     

Removal of duvatrienediols from the surface of tobacco leaves increases their susceptibility to blue mold

Dipping leaf strips of greenhouse or field-grown tobacco (Nicotiana tabacum L., cv. Ky-14) plants into acetone for 1 s, prior to inoculation with sporangia of Peronospora tabacina Adam, increased their susceptibility to blue mold. Disease severity and sporangial production on leaf discs from acetone-treated leaves were markedly increased compared to those on discs from untreated leaves. Treatment with acetone also decreased variation in susceptibility of leaves from plants of various ages. Disease severity on discs obtained from attached leaves which were dipped in acetone for 1 s was three times greater up to 15 days after dipping than on discs from leaves that were not dipped. TLC and GLC analyses of the acetone extracts indicated that 95% or more of the major cuticular diterpenoids, α- and β-4,8,13-duvatriene-1,3-diols (DVT), were removed from the surface by dipping for 1 s. These compounds had not reappeared on the leaf surface 15 days after leaves were dipped in acetone for 1 s. Aqueous suspensions of the acetone-soluble constituents as well as authentic DVT, inhibited sporangial germination of P. tabacina (ED₁₀₀ = 25 ppm) and the antifungal activity was accounted for by DVT. When DVT was removed from a leaf surface and added back to the same leaf strip, the resistance of the leaf tissue was restored. As tobacco plants aged, their susceptibility to blue mold decreased and the quantity of DVT on the leaf surface increased. The data support a role for DVT in the resistance of tobacco against blue mold.