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Commentary: EPA’s proposed expansion of dose-response analysis is a positive step towards improving its ecological risk assessment

Journal Paper
Agathokleous, E., Anav, A., Araminiene, V., De Marco, A., Domingos, M., Kitao, M., Koike, T., Manning, W.J., Paoletti, E., Saitanis, C.J., Sicard, P., Vitale, M., Wang, W., and Calabrese, E.J.
Environmental Pollution 246: 566-570
Publication year: 2019

Abstract

The United States Environmental Protection Agency (US EPA) has recently proposed changes to strengthen the transparency of its pivotal regulatory science policy and procedures. In this context, the US EPA aims to enhance the transparency of dose-response data and models, proposing to consider for the first time non-linear biphasic dose-response models. While the proposed changes have the potential to lead to markedly improved ecological risk assessment compared to past and current approaches, we believe there remain open issues for improving the quality of ecological risk assessment, such as the consideration of adaptive, dynamic and interactive effects. Improved risk assessment including adaptive and dynamic non-linear models (beyond classic threshold models) can enhance the quality of regulatory decisions and the protection of ecological health. We suggest that other countries consider adopting a similar scientific-regulatory posture with respect to dose-response modeling via the inclusion of non-linear biphasic models, that incorporate the dynamic potential of biological systems to adapt (i.e., enhancing positive biological endpoints) or maladapt to low levels of stressor agents.

A quantitative assessment of hormetic responses of plants to ozone

Journal Paper
Agathokleous, E., Araminiene, V., Belz, R.G., Calatayud, V., De Marco, A., Domingos, M., Feng, Z., Hoshika, Y., Kitao, M., Koike, T., Paoletti, E., Saitanis, C.J., Sicard, P., Calabrese, E.J.
Environmental Research, 176, art. no. 108527.
Publication year: 2019

Abstract

Evaluations of ozone effects on vegetation across the globe over the last seven decades have mostly incorporated exposure levels that were multi-fold the preindustrial concentrations. As such, global risk assessments and derivation of critical levels for protecting plants and food supplies were based on extrapolation from high to low exposure levels. These were developed in an era when it was thought that stress biology is framed around a linear dose-response. However, it has recently emerged that stress biology commonly displays non-linear, hormetic processes. The current biological understanding highlights that the strategy of extrapolating from high to low exposure levels may lead to biased estimates. Here, we analyzed a diverse sample of published empirical data of approximately 500 stimulatory, hormetic-like dose-responses induced by ozone in plants. The median value of the maximum stimulatory responses induced by elevated ozone was 124%, and commonly <150%, of the background response (control), independently of species and response variable. The maximum stimulatory response to ozone was similar among types of response variables and major plant species. It was also similar among clades, between herbaceous and woody plants, between deciduous and evergreen trees, and between annual and perennial herbaceous plants. There were modest differences in the stimulatory response between genera and between families which may reflect different experimental designs and conditions among studies. The responses varied significantly upon type of exposure system, with open-top chambers (OTCs) underestimating the maximum stimulatory response compared to free-air ozone-concentration enrichment (FACE) systems. These findings suggest that plants show a generalized hormetic stimulation by ozone which is constrained within certain limits of biological plasticity, being highly generalizable, evolutionarily based, and maintained over ecological scales. They further highlight that non-linear responses should be taken into account when assessing the ozone effects on plants.

Preconditioning in biology and medicine – Mechanisms and translational research

International Conference
Agathokleous E., Belz R.G., Calatayud V., De Marco A., Hoshika Y., Kitao M., Saitanis C.J., Sicard P., Paoletti E., and Calabrese E.J.
International Conference of the Dose-Response Society, 17-18 April 2018, Amherst, MA, USA.
Publication year: 2018

Penconazole: A potential ozone protectant of plants? A Metabolomics’ approach.

International Conference
Vougeleka V., Ntatsi G., Aliferis K.A., Saitanis C.J., Kalampokis J.F., Agathokleous E., and Savvas D.
International Conference on Ozone and Plant Ecosystems, 21-25 May 2018, Florence. Italy.
Publication year: 2018

Parasitoids and predators of Physokermes hellenicus (Hemiptera: Coccomorpha: Coccidae) in Greece

Journal Paper
Papanastasiou, I.,  Kavallieratos, N.G., Saitanis, C.J.,  Chatzaki, M.d,  Papadoulis, G.,  Emmanouel, N.G. 
Journal of Economic Entomology. 111(3), pp. 1121-1130
Publication year: 2018

Abstract

The genus Physokermes Targioni Tozzetti includes species that are distributed in the Holarctic region and feed on conifers. The recently described scale Physokermes hellenicus (Kozár and Gounari) (Hemiptera: Coccidae) is an endemic species of Greece whose host plants are fir trees of the genus Abies (Pinales: Pinaceae). It is considered as beneficial scale insect species since its honeydew secretions are exploited by honeybees leading to the production of a special honey with important physicochemical characteristics. Since there are no previous data on the natural enemies of P. hellenicus, an investigation was carried out during 2013 in forested areas of eight mountains in south and central Greece aiming to correlate the presence of P. hellenicus with certain parasitoids and predators. Seven species of Encyrtidae, Eulophidae, Pteromalidae, and Eurytomidae (Hymenoptera); five species of Anthribidae and Coccinellidae (Coleoptera); and four species of Dictinidae, Linyphiidae, and Theridiidae (Araneae) were identified. Twelve of them were identified at the species level while four at the genus level. Among them Microterys lunatus (Dalman) (Hymenoptera: Encyrtidae), Pseudorhopus testaceus (Ratzeburg) (Hymenoptera: Encyrtidae), and Anthribus fasciatus Forster (Coleoptera: Anthribidae) were the most abundant natural enemies of P. hellenicus adult female while Metaphycus unicolor Hoffer (Hymenoptera: Encyrtidae) and Trichomasthus sp. (Hymenoptera: Encyrtidae) were found to parasitize P. hellenicus male nymph. Cinetata gradata (Simon) (Araneae: Linyphiidae) is reported for first time in the Greek arachnofauna. Our results suggest that the abundance of the fir scale P. hellenicus could be affected by a complex of parasitoid and predator species of different taxa. Future long-term research on these species in relation with abiotic factors would help to understand possible fluctuation of the scale’s population.

Metabolic analysis of the effect of ethylenediurea (EDU) on Pinto bean (Phaseolus vulgaris L.) plants

National Conference
Vougeleka J.V., Ntatsi G., Agathokleous E., Savvas D., Aliferis K.A. and Saitanis, C.J.
19th Panhellenic Phytopathological Conference. Heraklion, Crete, Greece, 30 October - 1 November 2018
Publication year: 2018

How does elevated ozone affect the decomposition process in deciduous tree communities?

International Conference
Agathokleous E., De Marco A., Kato T., Kitao M., Koike T., Manning W.J., Ntatsi G., Paoletti, E., Saitanis C.J., Sarneel J., Sicard P., and Vitale M.
International Symposium on Forests and Health and Forum for Under-Forestry Economic Industry, 2-5 August 2018, Harbin, P.R. China. Extended Abstracts p.57
Publication year: 2018

Hormesis for predicting the effect of ozone on vegetation

International Conference
Agathokleous E., Belz R.G., Calatayud V., De Marco A., Hoshika Y., Kitao M., Saitanis C.J., Sicard P., Paoletti E., and Calabrese E.J.
Preconference workshop “Agriculture and Animal Husbandry in a Changing Climate”, “Climate Change in the Mediterranean and the Middle East: Challenges and Solutions”, 16-17 May 2018, Nicosia, Cyprus.
Publication year: 2018

High doses of ethylenediurea (EDU) as soil drenches did not increase leaf N content or cause phytotoxicity in willow grown in fertile soil

Journal Paper
Agathokleous E., Paoletti E., Manning W.J., Kitao M., Saitanis C.J., Koike T.
Ecotoxicology and Environmental Safety 147: 574-584
Publication year: 2018

Abstract

Ground-level ozone (O3) levels are nowadays elevated in wide regions of the Earth, causing significant effects on plants that finally lead to suppressed productivity and yield losses. Ethylenediurea (EDU) is a chemical compound which is widely used in research projects as phytoprotectant against O3 injury. The EDU mode of action remains still unclear, while there are indications that EDU may contribute to plants with nitrogen (N) when the soil is poor in N and the plants have relatively small leaf area. To reveal whether the N content of EDU acts as a fertilizer to plants when the soil is not poor in N and the plants have relatively large total plant leaf area, willow plants (Salix sachalinensis Fr. Schm) were exposed to low ambient O3 levels and treated ten times (9-day interval) with 200 mL soil drench containing 0, 800 or 1600 mg EDU L−1. Fertilizer was added to a nutrient-poor soil, and the plants had an average plant leaf area of 9.1 m2 at the beginning of EDU treatments. Indications for EDU-induced hormesis in maximum electron transport rate (Jmax) and ratio of intercellular to ambient CO2 concentration (Ci:Ca) were observed at the end of the experiment. No other EDU-induced effects on leaf greenness and N content, maximum quantum yield of photosystem II (Fv/Fm), gas exchange, growth and matter production suggest that EDU did not act as N fertilizer and did not cause toxicity under these experimental conditions.

Elevated O3 affects the decomposition process in different types of soil

International Conference
Agathokleous E., De Marco A., Kitao M., Koike T., Manning, W.J., Ntatsi G., Paoletti E., Saitanis C.J., Sarneel J., Sicard P., and Vitale M.
International Conference on Ozone and Plant Ecosystems, 21-25 May 2018, Florence. Italy.
Publication year: 2018

Effects of ozone (O3) and ethylenediurea (EDU) on the ecological stoichiometry of a willow grown in a free-air exposure system.

Journal Paper
Agathokleous, E., Kitao, M., Qingnan, C., Saitanis, C.J., Paoletti, E., Manning, W.J., Watanabe, T., Koike, T.
Environmental Pollution 238C: 663-676.
Publication year: 2018

Abstract

Ground-level ozone (O3) concentrations have been elevating in the last century. While there has been a notable progress in understanding O3 effects on vegetation, O3 effects on ecological stoichiometry remain unclear, especially early in the oxidative stress. Ethyelenediurea (EDU) is a chemical compound widely applied in research projects as protectant of plants against O3 injury, however its mode of action remains unclear. To investigate O3 and EDU effects early in the stress, we sprayed willow (Salix sachalinensis) plants with 0, 200 or 400 mg EDU L−1, and exposed them to either low ambient O3 (AOZ) or elevated O3 (EOZ) levels during the daytime, for about one month, in a free air O3 controlled exposure (FACE); EDU treatment was repeated every nine days. We collected samples for analyses from basal, top, and shed leaves, before leaves develop visible O3 symptoms. We found that O3 altered the ecological stoichiometry, including impacts in nutrient resorption efficiency, early in the stress. The relation between P content and Fe content seemed to have a critical role in maintaining homeostasis in an effort to prevent O3-induced damage. Photosynthetic pigments and P content appeared to play an important role in EDU mode of action. This study provides novel insights on the stress biology which are of ecological and toxicological importance.

Effect of ozone and/or EDU on Pinto bean plants’ metabolism

International Conference
Vougeleka V., Ntatsi G., Saitanis C.J., Aliferis K.A., Kalampokis J.F., Agathokleous E. and Savvas D.
International Conference on Ozone and Plant Ecosystems, 21-25 May 2018, Florence. Italy.
Publication year: 2018

Comparing the inoculation success of two bacteria strains, under different N supply levels, in the Greek bean landrace Zargana Chryssoupolis

International Conference
Vougeleka, V., Ntatsi, G., Saitanis, C., Tampakaki, A., Savvas, D.
TRUE Legume Innovation and Networking (LIN) - Workshop of the Mediterranean Region, Athens, Apr., 20, 2018, Book of Abstracts, page. 20
Publication year: 2018

Biological nitrogen fixation of vegetable legumes under reduced nitrogen or water supply

International Conference
Ntatsi, G., Vougeleka, V., Giannikos, G., Tsopelopoulos, K., Aliferis, K.A., Tampakaki, A., Saitanis, C.J., Savvas, D.
Proceedings of International Society for Horticultural Science (ISHS). XXX International Horticultural Congress. Tropical and Subtropical Vegetable Production: Tackling Present and Future Global Biotic and Abiotic Stressors, Insgtabul, Turkey, August 12-16
Publication year: 2018

Variety of Achhenorrhyncha species in alfalfa crops

National Conference
Ambatzi AP, Tsagarakis SA, Saitanis K. and Papadoulis G.Th.
17th Panhellenic Entomological Conference. 19-22 Sep. 1917. Agricultural University of Athens. p 13
Publication year: 2017