Αρχική » Έρευνα » Πρόσφατες Δημοσιεύσεις » Ερευνητικές Δημοσιεύσεις 2012

ΠΡΩΤΟΤΥΠΕΣ ΕΡΓΑΣΙΕΣ ΣΕ ΔΙΕΘΝΗ ΕΠΙΣΤΗΜΟΝΙΚΑ ΠΕΡΙΟΔΙΚΑ ΚΑΤΑ ΤΗ ΔΙΑΡΚΕΙΑ ΤΟΥ 2012

Apostolaki A., Harispe L., Calcagno-Pizarelli AM., Vangelatos I., Sophianopoulou V., Arst HN Jr., Peñalva MA., Amillis S., Scazzocchio C. (2012) Aspergillus nidulans CkiA is an essential casein kinase I required for delivery of amino acid transporters to the plasma membrane. Mol Microbiol 84:530-49.
 
Abstract: Type I casein kinases are highly conserved among Eukaryotes. Of the two Aspergillus nidulans casein kinases I, CkiA is related to the δ/ε mammalian kinases and to Saccharomyces cerevisiae Hrr25p. CkiA is essential. Three recessive ckiA mutations leading to single residue substitutions, and downregulation using a repressible promoter, result in partial loss-of-function, which leads to a pleiotropic defect in amino acid utilization and resistance to toxic amino acid analogues. These phenotypes correlate with miss-routing of the YAT plasma membrane transporters AgtA (glutamate) and PrnB (proline) to the vacuole under conditions that, in the wild type, result in their delivery to the plasma membrane. Miss-routing to the vacuole and subsequent transporter degradation results in a major deficiency in the uptake of the corresponding amino acids that underlies the inability of the mutant strains to catabolise them. Our findings may have important implications for understanding how CkiA, Hrr25p and other fungal orthologues regulate the directionality of transport at the ER-Golgi interface.
 
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.
 
Giannoutsou E., Galatis B., Zachariadis M., Apostolakos P. (2012) Formation of an endoplasmic reticulum ring associated with acetylated microtubules in the angiosperm preprophase band. Cytoskeleton 69:252-265
 
Abstract: We investigated the organization of the cortical endoplasmic reticulum (ER) in prophase cells of the angiosperms Zea mays, Triticum turgidum, and Vigna sinensis. In both symmetrically and asymmetrically dividing protodermal leaf cells, cortical ER was enriched in the preprophase band and colocalized there with microtubules, forming a ring-like structure (ER ring). In contrast, ER ring was absent from prophase root-tip cells of the same plants, suggesting that ER ring formation in the preprophase band is organ specific. Immunolabeling of the protodermal leaf cells revealed the presence of acetylated microtubules, which are more stable than the nonacetylated ones. In contrast, neither this post-translational modification of tubulin nor an accumulation of ER in the preprophase band was detected in root-tip cells. Experimentally delaying the maturation/disassembly of the microtubule ring of the preprophase band by taxol or cyclopiazonic acid treatment led to the appearance of ER ring and acetylated microtubules in the preprophase band. Together, our data show that in dividing cells of angiosperms, an ER ring associated with acetylated microtubules forms in the preprophase band.
 
Giannoutsou EPKatsifas EA, Geli A, Karagouni AD. (2012) Protein increase and lysine production by a Paecilomyces variotii strain grown on two-phase olive mill waste. World J Microbiol Biotechnol. 28(3): 849-56
 
Abstract: Two-phase olive-mill waste, the so-called "ecological", has been treated with a Paecilomyces variotii isolate in solid state fermentation experiments. The growth of the microorganism was estimated by measuring the production of carbon dioxide, using gas chromatography. A 46% increase of the protein content was achieved at the fermented product, after molasses addition at the initial mixture. The amino acid profile of the produced protein, as far as the essential amino acids are concerned, was significantly improved, resulting in a product that has the potential to be used as animal feed. Furthermore, it contains lysine, one of the essential amino acids that did not exist at the original product and is produced during fermentation. This is the first report on solid state fermentation of the two-phase olive mill waste (TPOMW) as a substrate, using a Paecilomyces variotii strain.
 
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.
 
Kelepertzis E., A. Argyraki, E. Valakos, E. Daftsis (2012) Distribution and accumulation of metals in tadpoles inhabiting the metalliferous streams of eastern chalkidiki, northeat Greece. Arch Envirom Contam. Toxicol. 63:409-420
 
Abstract: The present study investigates the accumulation of heavy metals [copper (Cu), lead (Pb), zinc (Zn), magnesium (Mn), cadmium (Cd), nickel (Ni), and chromium (Cr)] in tadpoles inhabiting the metalliferous streams flowing within the Asprolakkas River basin (northeast Chalkidiki peninsula, Greece) and the effect of potentially harmful elements in stream water and sediment on the corresponding levels in their tissue. Animals were collected from six sampling sites influenced by a wide range of surface water and stream sediment trace element concentrations. The results of the chemical analyses showed that tadpoles accumulated significant levels of all of the examined metals. The range of whole-body mean measured concentrations were (in dry mass) as follows: Cu (46–182 mg/kg), Pb (103–4,490 mg/kg), Zn (494–11,460 mg/kg), Mn (1,620–13,310 mg/kg), Cd (1.2–82 mg/kg), Ni (57–163 mg/kg), and Cr (38–272 mg/kg). The mean concentrations of Pb, Zn, Mn, Ni, Cr, and Cd in Kokkinolakkas stream, which drains a currently active mining area, were the highest ever reported in tadpoles. Our results indicate that whole-body levels of Pb, Zn, Cu, and Cd increase with stream sediment concentrations and that these organisms tend to accumulate metals bound to Fe and Mn oxides. In addition, high dissolved concentrations and significant concentrations associated with more labile geochemical phases of sediments for specific metals were contributing factors determining whole-body levels. Given the observed bioconcentration factors, as well as the correlation with sediment concentrations, it is proposed that these organisms could be considered as bioindicators of environmental contamination and may be used for monitoring purposes within this metal-rich zone and, perhaps, within other rivers affected by metal mining.
 
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.
 
Kosti V., Lambrinidis G., Myrianthopoulos V., Diallinas G., Mikros E. (2012) Identification of the substrate recognition and transport pathway in a eukaryotic member of the nucleobase-ascorbate transporter (NAT) family. PLoS One 7:e41939
 
Abstract: Using the crystal structure of the uracil transporter UraA of Escherichia coli,we constructed a 3D model of the Aspergillus nidulans uric acid-xanthine/H(+)symporter UapA, which is a prototype member of the Nucleobase-AscorbateTransporter (NAT) family. The model consists of 14 transmembrane segments (TMSs) divided into a core and a gate domain, the later being distinctly different from that of UraA. By implementing Molecular Mechanics (MM) simulations and quantitative structure-activity relationship (SAR) approaches, we propose a model for the xanthine-UapA complex where the substrate binding site is formed by the polar side chains of residues E356 (TMS8) and Q408 (TMS10) and the backbones of A407 (TMS10) and F155 (TMS3). In addition, our model shows several polar interactions between TMS1-TMS10, TMS1-TMS3, TMS8-TMS10, which seem critical for UapA transport activity. Using extensive docking calculations we identify a cytoplasm-facing substrate trajectory (D360, A363, G411, T416, R417, V463 and A469) connecting the proposed substrate binding site with the cytoplasm, as well as, a possible outward-facing gate leading towards the substrate major binding site. Most importantly, re-evaluation of the plethora of available and analysis of a number of herein constructed UapA mutations strongly supports the UapA structural model. Furthermore, modeling and docking approaches with mammalian NAT homologues provided a molecular rationale on how specificity in this family of carriers might be determined, and further support the importance of selectivity gates acting independently from the major central substrate binding site
 
Kotsakiozi, P., Pafilis, P., Giokas, S., Valakos, E. (2012): A comparison of the physiological responses of two land snail species with different distributional ranges. Journal of Molluscan Studies 78: 217-224
 
Abstract: Land snails usually exhibit cycles of activity and dormancy (aestivation or hibernation). The transition between these two states is accompanied by a range of behavioural and physiological responses to ensure their survival under adverse environmental conditions. Furthermore, aestivation plays an important role in shaping species’ distribution patterns. We examined the seasonal patterns in biochemical tissue composition in relation to aspects of behavioural ecology in three land snail populations: one mainland and one insular population of the widespread Helix aspersa and a population (sympatric with the latter) of Helix figulina, a congeneric species with a narrow and declining distribution.Helix figulina aestivates in underground borrows, while H. aspersa spends the summer under stones and may interrupt aestivation when conditions become favourable. Prior to aestivation H. figulina accumulates metabolic fuels, which it consumes later during summer, and at the same time loses substantial body water and increases lactate dehydrogenase (LDH) activity. The insular H. aspersa population follows a similar pattern (regarding metabolites and LDH activity), with the difference that water loss is limited. However, the mainland population of H. aspersa deviates from this model with energy metabolites and water levels showing little variation throughout the year, while LDH activity is reduced. These differences probably reflect the particular behavioural and physiological patterns adopted by each species. The specialist and range-restricted H. figulina shows a constant and more predictable seasonal pattern, which may be effective for surviving in its historical biogeographic range, but it seems to be more vulnerable to possibly changing environmental conditions. On the other hand the generalist and cosmopolitan H. aspersa adopts a more flexible pattern that compensates for the effects of adverse conditions during aestivation and permits a more effective exploitation of energy resources.
 
Kotsakiozi, P., Parmakelis, A., Giokas, S., Papanikolaou, I., Valakos, E. D. (2012): Mitochondrial phylogeny and biogeographic history of the Greek endemic land-snail genus Codringtonia Kobelt 1898 (Gastropoda, Pulmonata, Helicidae). Molecular Phylogenetics and Evolution 62: 681-692
 
Abstract: The aim of this work was to infer the phylogeny of the Greek endemic land-snail genus Codringtonia Kobelt 1898, estimate the time frame of the radiation of the genus, and propose a biogeographic scenario that could explain the contemporary distribution of Codringtonia lineages. The study took place in the districts of Peloponnese, Central Greece and Epirus of mainland Greece. Sequence data originating from three mtDNA genes (COI, COII, and 16S rDNA) were used to infer the phylogeny of the eight nominal Codringtonia species. Furthermore, the radiation time-frame of extant Codringtonia species was estimated using a relaxed molecular clock analysis and mtDNA substitution rates of land snails. The phylogenetic analysis supported the existence of six Codringtonia lineages in Greece and indicated that one nominal species (Codringtonia neocrassa) might belong to a separate genus distantly related to Codringtonia. The time frame of differentiation of Codringtonia species was placed in the Late Miocene–Pleistocene epoch. The dispersal–vicariance analysis performed indicated that most probably Codringtonia exhibited a north-to-south spread with the ancestral area being that of central Greek mainland, accompanied with duplication (speciation) and vicariance events.
 
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.
 
Krypotou E., Kosti V., Amillis S., Myrianthopoulos V., Mikros E., Diallinas G. (2012) Modeling, substrate docking, and mutational analysis identify residues essential  for the function and specificity of a eukaryotic purine-cytosine NCS1 transporter.  J Biol Chem 287:36792-803
 
Abstract: The recent elucidation of crystal structures of a bacterial member of the NCS1 family, the Mhp1 benzyl-hydantoin permease from Microbacterium liquefaciens, allowed us to construct and validate a three-dimensional model of the Aspergillus nidulans purine-cytosine/H(+) FcyB symporter. The model consists of 12 transmembrane α-helical, segments (TMSs) and cytoplasmic N- and C-tails. A distinct core of 10 TMSs is made of two intertwined inverted repeats (TMS1-5 and TMS6-10) that are followed by two additional TMSs. TMS1, TMS3, TMS6, and TMS8 form an open cavity that is predicted to host the substrate binding site. Based on primary sequence alignment, three dimensional topology, and substrate docking, we identified five residues as potentially essential for substrate binding in FcyB; Ser-85 (TMS1), Trp-159, Asn-163 (TMS3), Trp-259 (TMS6), and Asn-354 (TMS8). To validate the role of these and other putatively critical residues, we performed a systematic functional analysis of relevant mutants. We show that the proposed substrate binding residues, plus Asn-350, Asn-351, and Pro 353 are irreplaceable for FcyB function. Among these residues, Ser-85, Asn-163, Asn-350,  Asn-351, and Asn-354 are critical for determining the substrate binding affinity  and/or the specificity of FcyB. Our results suggest that Ser-85, Asn-163, and Asn-354 directly interact with substrates, Trp-159 and Trp-259 stabilize binding through π-π stacking interactions, and Pro-353 affects the local architecture of substrate binding site, whereas Asn-350 and Asn-351 probably affect substrate binding indirectly. Our work is the first systematic approach to address structure-function-specificity relationships in a eukaryotic member of NCS1 family by combining genetic and computational approaches.
 
Lamprinou V. Danielidis D.B., Economou-Amilli A. & A. Pantazidou (2012): Distribution survey of Cyanobacteria in three Greek caves of Peloponnese.- International Journal of Speleology, 41(2): 267-272.
 
Abstract: Caves and hypogean environments host various phototrophic microorganisms, with Cyanobacteria constituting the major group. The spatial and temporal distribution of Cyanobacteria (156 taxa in total) from three Greek caves, located in the limestone arc of Peloponnese and differing in morphology, was studied. The community patterns in different ecological niches were analyzed in relation to environmental parameters (photosynthetically active radiation, temperature, and relative humidity). Cyanobacterial communities were found to thrive in patchy biofilms and showed known protective strategies against desiccation and irradiation. The nMDS analysis of the cumulative seasonal samples per sampling site showed no general pattern of distribution, with a clear differentiation of cyanobacterial communities among the three caves. Only in the typical cave ‘Kastria’, cyanobacterial taxa showed growth habits in accordance with the gradient of light from entrance inwards.
 
Lamprinou, V., Skaraki K., Kotoulas G., Economou-Amilli A. & A. Pantazidou (2012): Toxopsis calypsus gen. nov. (Cyanobacteria, Nostocales) from cave ‘Francthi’, Peloponnese, Greece - Morphological and molecular evaluation.- International Journal of Systematic and Evolutionary Microbiology, 62: 2870-2877. 
 
Abstract: Representatives of a new cyanobacterial genus, Toxopsis Lamprinou & Pantazidou gen. nov., were found in fresh material from Cave ‘Francthi’ (Peloponnese, Greece) and isolated in cultures. Ecological data relating to the environmental parameters of the sampling sites are provided such as the photosynthetically active radiation (PAR), temperature and relative humidity. Morphological characteristics and the life cycle of the type species Toxopsis calypsus Lamprinou & Pantazidou sp. nov. were studied using light microscopy and scanning and transmission microscopy. Molecular analysis based on the 16S rRNA gene sequence was also conducted. Toxopsis calypsus sp. nov. is a false-branched nostocalean cyanobacterium with both isopolar and heteropolar filaments bearing mono-pored and bi-pored heterocysts, and also hormogonia and akinetes. Isopolar filaments adhere by the centre to the substrate and are found mainly in fresh material and in young cultures; heteropolar filaments bearing a basic monopore heterocyst are dominant in aged (more than one-year-old) cultures. According to the revised taxonomic classification system of Komárek & Anagnostidis (1989) based mainly on morphological data, the new genus described here shares morphological characters with both nostocalean families Scytonemataceae and Microchaetaceae, showing similarities in particular to Scytonematopsis contorta (Vaccarino & Johansen, 2011), Microchaetaceae. Molecular data from the 16S rRNA sequence determined in this paper showed that Toxopsis calypsus sp. nov. is more related to the family Microchaetaceae, and the five phylotypes analysed by PCR showed that the closest nostocalean relatives are Tolypothrix distorta SAG 93.79 (GenBank accession no  GQ287651) and Coleodesmium sp. ANT.L52B.5 (AY493596) with 95–96% and 96% similarity, respectively. In contrast, the five phylotypes showed a distant similarity to Scytonematopsis contorta (91%). The phenotypic and genetic traits strongly supported the classification of the five phylotypes as a new taxon for which the name Toxopsis calypsus Lamprinou & Pantazidou gen. nov., sp. nov. is proposed.
 
Livanos P., Galatis B., Quader H., Apostolakos P. (2012) Disturbance of reactive oxygen species homeostasis induces atypical tubulin polymer formation and affects mitosis in root-tip cells of Triticum turgidum and Arabidopsis thaliana. Cytoskeleton 69: 1-21
 
Abstract: In this study, the effects of disturbance of the reactive oxygen species (ROS) homeostasis on the organization of tubulin cytoskeleton in interphase and mitotic root-tip cells of Triticum turgidum and Arabidopsis thaliana were investigated. Reduced ROS levels were obtained by treatment with diphenylene iodonium (DPI) and N-acetyl-cysteine, whereas menadione was applied to achieve ROS overproduction. Both increased and low ROS levels induced: (a) Macrotubule formation in cells with low ROS levels and tubulin paracrystals under oxidative stress. The protein MAP65-1 was detected in treated cells, exhibiting a conformation comparable to that of the atypical tubulin polymers. (b) Disappearance of microtubules (MTs). (c) Inhibition of preprophase band formation. (d) Delay of the nuclear envelope breakdown at prometaphase. (e) Prevention of perinuclear tubulin polymer assembly in prophase cells. (f ) Loss of bipolarity of prophase, metaphase and anaphase spindles. Interestingly, examination of the A. thaliana rhd2/At respiratory burst oxidase homolog C (rbohc) NADPH oxidase mutant, lacking RHD2/AtRBOHC, gave comparable results. Similarly to DPI, the decreased ROS levels in rhd2 root-tip cells, interfered with MT organization and induced macrotubule assembly. These data indicate, for first time in plants, that ROS are definitely implicated in: (a) mechanisms controlling the assembly/disassembly of interphase, preprophase and mitotic MT systems and (b) mitotic spindle function. The probable mechanisms, by which ROS affect these processes, are discussed.
 
Livanos P., Apostolakos P., Galatis B. (2012) Plant cell division: ROS homeostasis is required. Plant Signaling and Behavior 7:771-778.
 
Abstract: Accumulated evidence indicates that ROS fluctuations play a critical role in cell division. Dividing plant cells rapidly respond to them. Experimental disturbance of ROS homeostasis affects: tubulin  polymerization; PPB, mitotic spindle and phragmoplast assembly; nuclear envelope dynamics; chromosome separation and movement; cell plate formation. Dividing cells mainly accumulate at prophase and delay in passing through the successive cell division stages. Notably, many dividing root cells of the rhd2 Arabidopsis thaliana mutants, lacking the RHD2/AtRBOHC protein function, displayed aberrations, comparable to those induced by low ROS levels. Some protein molecules, playing key roles in signal transduction networks inducing ROS production, participate in cell division. NADPH oxidases and their regulators PLD, PI3K and ROP-GTPases, are involved in MT polymerization and organization. Cellular ROS oscillations function as messages rapidly transmitted through MAPK pathways inducing MAP activation, thus affecting MT dynamics and organization. RNS implication in cell division is also considered.
 
Louvrou I.A. Economou-Amilli (2012): Transfer of four taxa of genus Nitzschia Hassal to genus Psammodictyon D.G. Mann (Bacillariophyceae).- Journal of Biological Research-Thessaloniki, 17: 148-153.
 
Abstract: The following four diatom taxa found in hydrothermal sites of Milos Island - three of them representing new records for the Greek diatom flora - are transferred from genus Nitzschia Hassall 1845 to the recently described genus Psammodictyon D.G. Mann in Round et al. 1990: Psammodictyon constrictum f. parvum (Grunow) Belegratis, Louvrou & Economou-Amilli comb. nov., Psammodictyon panduriforme var. latum (O.N. Witt) Louvrou & Economou-Amilli comb. nov., Psammodictyon panduriforme var. peralbatum (H. Peragallo & Peragallo) Louvrou & Economou-Amilli comb. nov., Psammodictyon subconstrictum (Grunow) Louvrou & Economou-Amilli stat. nov., comb. nov.
 
Louvrou I, Danielidis DB, Economou-Amilli A (2012): Meloneis gen. nov., a new epipsammic genus of Rhaphoneidaceae (Bacillariophyceae).- PLoS ONE 7(3): e32198. doi:10.1371/journal.pone.0032198.
 
Abstract: The diatom family Rhaphoneidaceae is characterized by high generic diversity and low species diversity with most genera known to have long stratigraphic ranges. The genera within this family are neritic marine, and mostly epipsammic. A new modern and epipsammic genus, Meloneis gen. nov., is described herein and is compared to all genera within Rhaphoneidaceae and especially to Rhaphoneis Ehrenberg s.l. Within Meloneis three new species and one variety are distinguished and described herein: M. mimallis sp. nov., M. mimallis var. zephyria var. nov., M. akytos sp. nov., and M. gorgis sp. nov.
 
Mavrofrydi O and Papazafiri P. (2012) Hypoxia-inducible factor-lα increase is an early and sensitive marker of lung cells responding to benzo[a]pyrene. J Environ Pathol Toxicol Oncol. 2012;31(4):335-47
 
Abstract: Hypoxia inducible factor-1α (HIF-lα) is a central regulator of tumor survival and metastasis, responsible for metabolic adaptation to hypoxic conditions and promotion of angiogenesis. It has been also shown to respond to non-hypoxic stimuli, such as growth factors and moderate oxidative stress. We examined the protein levels of HIF-lα in A549 human lung cells exposed to the typical carcinogen benzo[a]pyrene (B[a]P). Our results revealed that B[a]P, at low, non-cytotoxic concentrations, induced a transient increase of nuclear HIF-lα and its target, GLUT1. HIF-lα upregulation was partly mediated by Akt kinase and coincided with increased nuclear levels of the redox-sensitive marker, nuclear factor erythroid 2-related factor-2 (NrF-2). B[a]P-induced HIF-lα was also detected during serum depletion or treatment with the hypoxia-mimicking agent, CoCl2. In addition, exposure of A549 cells to B[a]P containing diesel exhaust particles enhanced HIF-lα accumulation, probably due to the presence of additional carcinogenic compounds. B[a]P-induced increase of HIF-lα was further confirmed in normal rat and human lung fibroblasts. Our findings indicate that HIF-lα stimulation may act as an early and sensitive marker of exposure to low, non-cytotoxic concentrations of B[a]P and/or other carcinogens.
 
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.
 
Takeshita N., Diallinas G., Fischer R. (2012) The role of flotillin FloA and stomatin StoA in the maintenance of apical sterol-rich membrane domains and polarity in the filamentous fungus Aspergillus nidulans. Mol Microbiol 83:1136-52
 
Abstract: Apical sterol-rich plasma membrane domains (SRDs), which can be viewed using the  sterol-binding fluorescent dye filipin, are gaining attention for their important roles in polarized growth of filamentous fungi. The microdomain scaffolding protein flotillin/reggie and related stomatin were thought to be good candidates involved in the formation of SRDs. Here, we show that the flotillin/reggie orthologue FloA tagged with GFP localized as stable dots along the plasma membrane except hyphal tips. Deletion of floA reduced the growth rate, often resulted in irregularly shaped hyphae and impaired SRDs. In contrast, the stomatin orthologue StoA, tagged with GFP, localized at the cortex of young branch tips and at the subapical cortex in long hyphal tips, and was transported bi-directionally along microtubules on endosomes. Deletion of stoA resulted in irregular hyphal morphology and increased branching especially in young hyphae, but did not obviously affect SRDs. Double deletion of floA and stoA enhanced the  defects of growth and hyphal morphology. Our data suggest that the plasma membrane of hyphal tips and in subapical regions are distinct and that FloA is involved in membrane compartmentalization and probably indirectly in SRD maintenance
 
Terauchi M., Nagasato C., Kajimura N., Mineyuki Y., Okuda K., Katsaros C., Motomura T (2012) Ultrastructural Study on Plasmodesmata in the Brown Alga Dictyota dichotoma (Dictyotales, Phaeophyceae). Planta 236 (4), 1013-1026, DOI 10.1007/s00425-012-1656-4
 
Abstract: Plasmodesmata are intercellular bridges that directly connect the cytoplasm of neighboring cells and play a crucial role in cell-to-cell communication and cell development in multicellular plants. Although brown algae (Phaeophyceae, Heterokontophyta) are phylogenetically distant to land plants, they nevertheless possess a complex multicellular organization that includes plasmodesmata. In this study, the ultrastructure and formation of plasmodesmata in the brown alga Dictyota dichotoma were studied using transmission electron microscopy and electron tomography with rapid freezing and freeze substitution. D. dichotoma possesses plasma membrane-lined, simple plasmodesmata without internal endoplasmic reticulum (desmotubule). This structure differs from those in land plants. Plasmodesmata were clustered in regions with thin cell walls and formed pit fields. Fine proteinaceous ‘‘internal bridges’’ were observed in the cavity. Ultrastructural observations of cytokinesis in D. dichotoma showed that plasmodesmata formation began at an early stage of cell division with the formation of tubular preplasmodesmata within membranous sacs of the cytokinetic diaphragm. Clusters of pre-plasmodesmata formed the future pit field. As cytokinesis proceeded, electron-dense material extended from the outer surface of the mid region of the pre-plasmodesmata and finally formed the nascent cell wall. From these results, we suggest that pre-plasmodesmata are associated with cell wall development during cytokinesis in D. dichotoma.
 
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.