Temporal arsenic form changes dynamics and accumulation patterns in Tilia cordata Mill. seedlings: Insights into metalloid transformation and tolerance mechanisms in trees.

Arsenic (As) remediation is challenging due to the complex nature and the persistence of these metalloid compounds. While it may seem that differences between As forms influence have been extensively described, new findings challenge the previously accepted knowledge, particularly for woody plants. Therefore, this study focused on 2-year-old Tilia cordata Mill. seedlings early (0, 2, 4, 12, 24 h) and late (3, 7, 12, 18, 25, 33 days) responses during growth under: As(III), As(V) or dimethylarsinic acid (DMA) (0.3 mM). Time-dependent transformations of As forms, distribution in plants, and microbiological characteristics (actinobacteria, bacteria, fungi, enzyme activity) were investigated. The highest increase in total As content was observed in plants exposed to As(V) and As(III). Dynamic metalloid form changes in the solution and tree organs were indicated. The most phytotoxic was DMA. This form was the main factor limiting the growth and effective accumulation of As. Despite experimenting in hydroponics, microorganisms played an important role in As form transformations, suggesting the potential for microbial-assisted dendroremediation strategies. The study confirmed that trees can convert more toxic forms into less toxic ones (e.g. As(III) to phytochelatins - As(III)-(PC3)), whose presence in roots seedlings exposed to As(III) and As(V) has been identified. The formation of hydrophobic forms (e.g. dimethylarsinoyl lipid) in the roots of seedlings grown under As(V) was confirmed. It is the first discovery for trees, previously observed only in bacteria and algae. The dynamics of metalloid form changes indicated that T. cordata transforms As forms according to their needs, which may give tree species an advantage in phytoremediation techniques. It holds great promise for the potential of dendroremediation.

Lower dose of plant substance more effective in repelling Rhyzopertha dominica F . (Coleoptera, Bostrichidae) and Sitophilus granarius L. (Coleoptera, Dryophthoridae).

INTRODUCTION AND OBJECTIVE: The study compares the effect of two concentrations (0.1% and 1%) of plant material on repelling two dangerous stored pests - Rhyzopertha dominica F. and Sitophilus granarius L. Both species were treated with the essential oils of Foeniculum vulgare Mill., Carum carvi L., Mentha pulegium L., and Cananga odorata (Lam.) Hook.f. & Thomson, as well as the chemicals contained in these oils: anethole, L-carvone, pulegone and thymoquinone. MATERIAL AND METHODS: Laboratory tests were carried out at 29±1 °C with 60±5% relative humidity (RH). Repellence of insects were noted after 1, 2, 3, 4, 5, 24 and 48 h. RESULTS: A lower dose of essential oils and some of the tested compounds caused a stronger repellence in the specified species of beetles. In the case of R. dominica, the concentration of 0.1% pulegone and L-carvone had the greatest repellent effect. Differences in the repellence of R. dominica were found between the concentrations of 0.1%-1% among all the tested substances in each time interval. This difference ranged from 5.0%-52.92%. All substances used in the tests had a strong repellent effect on S. granarius (30%-100%). There were differences in the repellency of S. granarius between 0.1%-1% concentration in most of the tested substances in each time interval, but they were not as large as for R. dominica.. CONCLUSIONS: The most interesting results were obtained concerning the relationship: the lower tested substance concentration caused a much stronger repellent effect of R. dominica and S. granarius..

The Identification of Potential Immunogenic Antigens in Particular Active Developmental Stages of the Rice Weevil (Sitophilus oryzae).

BACKGROUND: The rice weevil (Sitophilus oryzae) originates from subtropical and tropical areas of Asia and Africa, but it also appears on other continents, mostly as a result of trade in rice. It may occur in grain fields as well as in storage facilities, and cause allergenic reactions. The aim of this study was to identify the potential antigens in all developmental stages of S. oryzae, which may cause an allergic response in humans. METHODS: Sera of 30 patients were tested for the presence of IgE antibodies to antigens from three life stages of the rice weevil. To identify protein fractions containing potential allergens, proteins collected from larvae, pupae, and adults separated by sex of S. oryzae were fractionated by SDS-PAGE. Then, they were probed with anti-human, anti-IgE monoclonal antibodies, fractionated by SDS-PAGE and detected by Western blotting. RESULTS: In total, 26 protein fractions of males and 22 fractions of other life stages of S. oryzae (larvae, pupae, and females) positively reacted with the examined sera. CONCLUSIONS: The conducted study showed that S. oryzae may be a source of many antigens which may cause the potential allergic reactions in humans.

Valorization of the Red Algae Gelidium sesquipedale by Extracting a Broad Spectrum of Minor Compounds Using Green Approaches.

Until now, the red algae Gelidium sesquipedale has been primarily exploited for agar production, leaving an undervalued biomass. In this work, the use of eco-friendly approaches employing ultrasound-assisted extraction (UAE) and green solvents was investigated to valorize the algal minor compounds. The green methods used herein showed an attractive alternative to efficiently extract a broad spectrum of bioactive compounds in short extraction times (15 to 30 min vs. 8 h of the conventional method). Using the best UAE conditions, red seaweed extracts were characterized in terms of total phenolics (189.3 ± 11.7 mg GAE/100 g dw), flavonoids (310.7 ± 9.7 mg QE/100 g dw), mycosporine-like amino acids (MAAs) (Σ MAAs = 1271 mg/100 g dw), and phycobiliproteins (72.4 ± 0.5 mg/100 g dw). Additionally, produced algal extracts exhibited interesting antioxidant and anti-enzymatic activities for potential applications in medical and/or cosmetic products. Thus, this study provides the basis to reach a superior valorization of algal biomass by using alternative methods to extract biologically active compounds following eco-friendly approaches. Moreover, the strategies developed not only open new possibilities for the commercial use of Gelidium sesquipedale, but also for the valorization of different algae species since the techniques established can be easily adapted.

Repellent Effect of the Caraway Carum carvi L. on the Rice Weevil Sitophilus oryzae L. (Coleoptera, Dryophthoridae).

The aim of the study was to check the effect of Carum carvi L. essential oil and L-carvone on the emigration, repellence and mortality of Sitophilus oryzae L. In the experiments with caraway essential oil, concentrations of 0.1%, 0.5% and 1% were used, and concentrations of 0.05, 0.1, 0.5 and 1% were used with L-carvone. We assessed whether, in what concentrations and after what exposure time the substances acted on S. oryzae as repellents and/or insecticides. The laboratory tests were carried out at 29 ± 1 °C with 60 ± 5% relative humidity (RH). The deterrence, mortality and abundance of insects were noted after 1, 2, 3, 4, 5, 24 and 48 h. For caraway essential oil and L-carvone, the highest repellency was not shown in the highest concentrations that were used in the tests but in the lower concentrations of 0.5% and 0.1%, respectively. In all used concentrations, caraway essential oil showed repellent effects on S. oryzae. The highest repellency (60-98%) was caused by 0.5% caraway essential oil after 1, 2, 3, 4 and 5 h of research and by 0.1% L-carvone (16-100%). The highest mortality of S. oryzae was caused by 0.5% caraway essential oil and 1% L-carvone. L-carvone at a concentration of 0.05% did not cause mortality in S. oryzae. In conclusion, the greatest repellent effects on S. oryzae were caused by lower doses of caraway essential oil and L-carvone. These compounds do not show the normal relationship described in the previous literature on warehouse pests, in which the repellency increased with increasing concentrations of the tested plant material.