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Argiropoulos A., Rhizopoulou S. (2012) Micromorphology of the petals of the invasive weed, Oxalis pes-caprae. Weed Biology and Management 12, 47–52 (doi:10.1111/j.1445-6664.2012.00434.x)
Abstract: The alien, seedless Oxalis pes-caprae has spread and colonized many areas of the Mediterranean Basin, relying on vegetative reproduction.The flowering of O. pes-caprae is greatly accelerated by its exposure to sunlight.When the sun is shining, both sides of the petals of the funnelshaped, open flowers of O. pes-caprae are exposed to the ambient conditions. In cloudy weather, only some portions of the abaxial petal surfaces of the trumpet-shaped, closed flowers of O. pes-caprae are exposed to the ambient conditions. The micromorphology of the petals of O. pes-caprae was imaged by using light, scanning and atomic force microscopy. In O. pes-caprae, conical cells are found only on the adaxial epidermis of the petals, which also consist of a narrow mesophyll with a loosely arranged parenchyma and convex cells on their abaxial epidermis. High-resolution imaging of the petal surfaces, using atomic force microscopy, revealed that the epidermal cells are further ornamented by submicron sculptures, indicating a different roughness, density, and arrangement of the folds between the adaxial and abaxial sides of the petals. Submicron sculpturing increases the surface area of the adaxial epidermal cells of the petals and the distances between the folds are almost equal to the visible waveband.On the abaxial epidermal cells, the distances between the folds are smaller than the subwavelength spectrum.The high and the negligible values of roughness that were obtained on the adaxial and the abaxial surfaces might facilitate the capture and the reflection of light, respectively.
Argiropoulos A., Rhizopoulou S. (2012) Topography and nanosculpture of petals’ surfaces of short-lived flowers of the wild species Cistus creticus, Cistus salviifolius, Eruca sativa and Sinapis arvensis. Botanical Studies 53: 479-488
Abstract: The adaxial and the abaxial petal surface of short-lived flowers of the successively blossoming species Sinapis arvensis, Eruca sativa, Cistus creticus and Cistus salviifolius were examined using light microscopy, scanning electron microscopy and atomic force microscopy. The topography of petals revealed a submicron relief that is expected to influence the visual appearance and the wettability of floral tissues. Adaxial, papillate epidermal cells of petals and mesophylls consistent of loosely arranged cells and large intercellular spaces produce conditions of coordinated light trapping areas, affecting the light use efficiency and the likelihood of changing optical properties of the tissues. Visualization of the petals’ epidermises using an atomic force microscope revealed a microrelief that increases the cell surface area of the epidermal cells and this may be a well adapted mechanism to a short floral span. Distinct striations on the petal surfaces of Sinapis arvensis and Eruca sativa may strengthen the delicate tissues and influence the adhesive contacts, during a three-day floral span. Smooth petal surfaces of ephemeral flowers of Cistus creticus and Cistus salviifolius may show strong reflections. High resolution imaging shows that roughening of the adaxial surface of petals is higher than that of the abaxial surface, in all the above mentioned species. Traits of micromorphology of the epidermal surface of short-lived petals may be particularly important for the performance of flowers of wild species grown under ambient conditions.
Chimona C., Stamellou A., Argiropoulos A., Rhizopoulou S. (2012) Study of variegated and white flower petals of Capparis spinosa expanded at dusk in arid landscapes. Journal of Arid Land 2012, 4(2): 171−179 (doi: 10.3724/SP.J.1227.2012.00171)
Abstract: In this study, we provide the first evidence of two pairs of petals of the rapidly expanded and short-lived nocturnal flowers of Capparis spinosa L. (caper) during the prolonged drought period in Eastern Mediterranean region. The corolla of the winter-deciduous, perennial C. spinosa consists of two pairs of petals: a pair of white distinct petals and a pair of connate variegated petals with green basal parts. The results indicated the presence of substantially different amounts of chlorophyll in the two pairs of petals, while their carbohydrates’ content is comparable with that of the green sepals. High resolution imaging of petal surfaces of short-lived flowers of C. spinosa, obtained by using scanning electron microscopy, revealed stomata on the adaxial epidermis on both the white and the green parts of the variegated petals; while dense hairs were found on the surface of the abaxial green parts of the variegated petals. Adaxial, epidermal cells of the variegated petals, viewed using atomic force microscopy, possess a submicron, cuticular microfolding that differs between the white and the green parts of the petals. It appears that microridges on the adaxial, white parts of petals of C. spinosa compensate for an increase in cell surface area of the short lived petals, while the roughness of the green parts of petals was found to be higher than that of the white parts. Thus, the micromorphology of surfaces of epidermal cells is expected to affect optical properties and wettability of the floral tissues. These findings may be particularly important for understanding the performance of the short-lived petals of C. spinosa, which are exposed to dryland environments..
Fragopoulou AF, Samara A, Antonelou MH, Xanthopoulou A, Papadopoulou A, Vougas K, Koutsogiannopoulou E, Anastasiadou E, Stravopodis DJ, Tsangaris GT, Margaritis LH. (2012) Brain proteome response following whole body exposure of mice to mobile phone or wireless DECT base radiation. Electromagn Biol Med. 2012 Jan 20. [Epub ahead of print]
Abstract: The objective of this study was to investigate the effects of two sources of electromagnetic fields (EMFs) on the proteome of cerebellum, hippocampus, and frontal lobe in Balb/c mice following long-term whole body irradiation. Three equally divided groups of animals (6 animals/group) were used; the first group was exposed to a typical mobile phone, at a SAR level range of 0.17-0.37 W/kg for 3 h daily for 8 months, the second group was exposed to a wireless DECT base (Digital Enhanced Cordless Telecommunications/Telephone) at a SAR level range of 0.012-0.028 W/kg for 8 h/day also for 8 months and the third group comprised the sham-exposed animals. Comparative proteomics analysis revealed that long-term irradiation from both EMF sources altered significantly (p < 0.05) the expression of 143 proteins in total (as low as 0.003 fold downregulation up to 114 fold overexpression). Several neural function related proteins (i.e., Glial Fibrillary Acidic Protein (GFAP), Alpha-synuclein, Glia Maturation Factor beta (GMF), and apolipoprotein E (apoE)), heat shock proteins, and cytoskeletal proteins (i.e., Neurofilaments and tropomodulin) are included in this list as well as proteins of the brain metabolism (i.e., Aspartate aminotransferase, Glutamate dehydrogenase) to nearly all brain regions studied. Western blot analysis on selected proteins confirmed the proteomics data. The observed protein expression changes may be related to brain plasticity alterations, indicative of oxidative stress in the nervous system or involved in apoptosis and might potentially explain human health hazards reported so far, such as headaches, sleep disturbance, fatigue, memory deficits, and brain tumor long-term induction under similar exposure conditions.
Katsarou A, Rhizopoulou S, Kefalas P (2012) Antioxidant Potential of the Aerial Tissues of the Mistletoe Loranthus europaeus Jacq. Rec. Nat. Prod. 6:4 (2012) 394-397
Abstract: The aim of the study was to evaluate the antioxidant activity of extracts of aerial tissues (i.e. flowers, leaves, stems, twigs and berries) of the mistletoe Loranthus europaeus that grow on oak trees in a natural forest, in the mainland of Greece. Total phenolic content and antioxidant potential of aerial issues of L. europaeus was evaluated by the Folin-Ciocalteu method, the Ferric reducing antioxidant power assay, the free radical DPPH scavenging and the Co(II)/EDTA induced luminol plateau chemiluminescence assay. Extracts of twigs and stems of L. europaeus exhibited higher antioxidant activity in comparison to that of fruits, leaves and flowers.
Kolyva Foteini, Stratakis Emmanuel, Rhizopoulou Sophia, Chimona Chrysanthi, Fotakis Costas (2012) Leaf surface characteristics and wetting in Ceratonia siliqua L. Flora 207 (2012) 551– 556
Abstract: Compound leaves of Ceratonia siliqua L. (carob tree) exhibit a long life span and are exposed to environmental stimuli for approximately twenty months. The micromorphology of the adaxial and the abaxial leaflet surfaces was studied, in comparison with treated waxless epidermises (after the removal of cuticle and epicuticular waxes) and corresponding replicas, respectively. The microstructural surface features are evaluated as possible consistent parameters related to the wetness of leaves. The abaxial leaflet surface is more hydrophobic than the adaxial leaflet surface in C. siliqua, which may be particularly important for the ecophysiological status of its hypostomatic leaves.
Koutsias N., Arianoutsou M., Kallimanis A.S., Mallinis G., Halleyd J.M., Dimopoulos P. (2012) Where did the fires burn in Peloponnisos, Greece the summer of 2007? Evidence for a synergy of fuel and weather. Agricultural and Forest Meteorology 156 (2012) 41– 53, DOI:10.1016/j.agrformet.2011.12.006
Abstract: The aim of this study is to explore the burning pattern of the catastrophic wildfires that occurred in Peloponnisos, southern Greece, in 2007. These fires caused the loss of 67 lives and were recognized as the most extreme natural disaster in the country’s recent history. We compare the 2007 fires against fuel availability across the landscape in the light of a null model using Monte-Carlo randomization and against the fire pattern for the preceding period, 2000–2006. Additionally we applied a multi-response permutation-procedure test, a data-driven method free from assumptions about the underlying distribution. The study contributes to the ongoing debate over the relative importance of fuel versus weather in explaining large and intense wildfires. While the majority of the 2007 wildfires burned low-elevation fire-prone ecosystems, a part of them moved to non-fire-prone ecosystems, indicating a departure from the burning pattern of recent history. The CORINE land-cover categories most affected by fire included agricultural lands highly interspersed with large areas of natural vegetation followed by sclerophyllous vegetation, transitional woodland shrubs, complex cultivation patterns and olive groves. These reflect greater fuel accumulation through the encroachment of natural vegetation in abandoned fields as well as changing patterns of land-use. The rising proportions of humid and sub-humid areas burned are clearly related to weather patterns. The synergistic effect between fuel and weather helps explain the unusually large 2007 wildfires in Peloponnisos. This change may imply a climatically driven alteration of the established fire-regime promoted by fuel accumulation that portends major ecological consequences. The ecological disaster foreseen is justified by the lack of specific adaptations to cope with fire in non fire-prone plant communities.
Meletiou-Christou, Maria-Sonia & Rhizopoulou, Sophia. (2012) Constraints of photosynthetic performance and water status of four evergreen species co-occurring under field conditions. Botanical Studies 53 (3): 325-334.
Abstract: Leaf water status and photosynthetic characteristics were investigated in four evergreen species, i.e. Laurus nobilis Ligustrum japonicum, Nerium oleander and Pittosporum tobira, grown under ambient conditions. The results reveal variations in photosynthetic traits in relation to the use of water, during the optimal period of growth, in the middle of the dry season, during the secondary growth period and in the middle of the cold and wet season. Photosynthesis was restricted by limitations of stomatal conductance, causing transpiration impairment in L. nobilis, L. japonicum and P. tobira; while, the opposite holds true for N. oleander. Stomatal conductance of N. oleander was higher than that of the three co-existing species, sustaining elevated rates of photosynthesis and transpiration, at the expense of water. As drought progressed, there was a reduction in photosynthesis and water use efficiency in L. japonicum and P. tobira. Leaf turgor of the four species was closely associated with leaf water potential and differences among species narrowed in the dry season. The results show that L. nobilis possess features that confer advantage for the maintenance of this species in the driest sites, N. oleander maximises gas exchanges in the dry season by exhibiting a capacity for water acquisition, while L. japonicum and P. tobira may be limited to the moist sites.
Paraskeva-Hadjichambi D., Korfiatis K., Hadjichambis A., Arianoutsou M. (2012) Conservation reasoning and proposed actions for the protection of threatened plant species: Insights from a sample of rural and urban children of Cyprus. Society & Natural Resources, DOI:10.1080/08941920.2011.642461
Abstract: Investigating children’s beliefs and values toward threatened biodiversity can contribute to their understanding about nature and to the prevention of ociopolitical issues that may emerge when nature policy is being implemented. This study investigates children’s beliefs about threats to plants, the personal values associated with conservation, and actions children consider desirable regarding the conservation of three threatened plant species of Cyprus. Photos of threatened plants were used during interviews with 60 students (30 urban and 30 rural residents) aged 10–12 years. Results showed that participants deemphasized anthropogenic threats, while attitudes of individual responsibility were prevalent. Participants proposed actions of higher effectiveness mainly when they felt that they would be able to implement them. Findings suggest that an educational policy on threatened plant conservation should adopt a social character, focusing on attitudinal development and participatory learning approaches that will enhance children’s sense of ownership and efficacy.
Rhizopoulou, Sophia. (2012) Changing mediterranean environment: irrefutable evidence from pre-industrial, unpublicised scenes contemporary with a mission (1786-1787) in the Levant. Global Nest Journal 14 (4): 516-524.
Abstract: This paper provides an introduction to one hundred thirty one, pre-industrial, unpublicised Mediterranean scenes kept in Oxford, which constitute valuable evidence of changing environment. The largely unknown and unpublished paintings witness environmental wilderness and the cultural landscapes of the region, late in the 18th century. They depict sixty two scenes from Greece, forty two from Turkey, twenty two from Italy, three from Cyprus and two from Gibraltar. The paintings reveal changes that have occurred over the last two centuries in Mediterranean ecosystems; uninhabited areas, mountainous expanses, coastal regions, and Aegean islands. The region belongs to the hotspots of the biodiversity on Earth. Scientific interest in archival material has been revived, on account of research into a diversity threatened by anthropogenic activities and climate change. In this context, unknown Mediterranean scenes of 18th century offer another perspective on this complex subject of enquiry, they support efforts towards protection and preservation of natural environment and heighten interest in the management of diverse Mediterranean ecosystems.
Thanasopoulou A, Xanthopoulou AG, Anagnostopoulos AK, Konstantakou EG, Margaritis LH, Papassideri IS, Stravopodis DJ, Tsangaris GT, Anastasiadou E (2012) Silencing of CCDC6 reduces the expression of 14-3-3σ in colorectal carcinoma cells. Anticancer Res. 2012 Mar;32(3):907-13.
Abstract: Coiled-coil domain containing 6 (CCDC6) is frequently rearranged in papillary thyroid carcinomas participating in the formation of RET/PTC1 oncogene. Other rearrangements involving CCDC6 have also been identified demonstrating its high susceptibility to chromosomal recombination. Malignancies bearing CCDC6 fusion genes are developed in a background where CCDC6 is either lost or deregulated. Our aim was to identify interacting proteins which are affected by the silencing of CCDC6 expression and could possibly link CCDC6 deregulation to cancer causality. Therefore, a proteomic approach was adopted using a human cancer cell-line (HCT116) where CCDC6 expression was silenced by lentiviral shRNA constructs. 14-3-3σ down-regulation in the absence of CCDC6 was revealed and verified by western blot analysis and confocal microscopy. Only the levels and not the topology of CCDC6 were altered. The down-regulation of 14-3-3σ in the absence of CCDC6 demonstrated their direct association and supports the notion that CCDC6 contributes to cancer development, possibly through malignant pathways involving 14-3-3σ.