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Anasontzis GE, Zerva A, Stathopoulou PM, Haralampidis K, Diallinas G, Karagouni AD, Hatzinikolaou DG. (2011) Homologous overexpression of xylanase in Fusarium oxysporum increases ethanol productivity during consolidated bioprocessing (CBP) of lignocellulosics. J Biotechnol. 152(1-2):16-23.
Abstract: In an effort to increase ethanol productivity during the consolidated bioprocessing (CBP) of lignocellulosics by Fusarium oxysporum, we attempted the constitutive homologous overexpression of one of the key process enzymes, namely an endo-xylanase. The endo-β-1,4-xylanase 2 gene was incorporated into the F. oxysporum genome under the regulation of the gpdA promoter of Aspergillus nidulans. The transformation was effected through Agrobacterium tumefaciens and resulted in 12 transformants, two of which were selected for further study due to their high extracellular xylanase activities under normally repressing conditions (glucose as sole carbon source). During natural induction conditions (growth on xylan) though, the extracellular enzyme levels of the transformants were only marginally higher (5-10%) compared to the wild type despite the significantly stronger xylanase 2 mRNA signals. SDS-PAGE verified enzyme assay results that there was no intracellular xylanase 2 accumulation in the transformants, suggesting the potential regulation in a post transcriptional or translational level. The fermentative performance of the transformants was evaluated and compared to that of the wild type in simple CBP systems using either corn cob or wheat bran as sole carbon sources. Both transformants produced approximately 60% more ethanol compared to the wild type on corn cob, while for wheat bran this picture was repeated for only one of them. This result is attributed to the high extracellular xylanase activities in the transformants' fermentation broths that were maintained 2-2.5-fold higher compared to the wild type.
Andreou M., Delipetrou P., Kadis C., Tsiamis G., Bourtzis K., Georghiou K. (2011) An integrated approach for the conservation of threatened plants: The case of Arabis kennedyae (Brassicaceae). Acta Oecologica (in press - DOI: 10.1016/j.actao.2011.02.007)
Abstract: The aim of this paper is to propose an integrated approach (including population and habitat monitoring and the study of reproductive biology and genetic diversity) for the comprehensive study of threatened plants, for which conservation measures are imperative. We applied this model to the plant species Arabis kennedyae which is classified as endangered according to the IUCN criteria. The current population of the species consists of three small subpopulations (AR1, AR2, and AR3) at three locations. Population size was characterized by considerable annual fluctuations. The distribution pattern of the plant followed habitat availability. Relative Reproductive Success remained stable but moderate. Germination of dormant seeds was promoted by light and was optimal at 15 and 20 C. Genetic analysis showed low interpopulation variability and detected two groups: haplotype I (AR1 and AR3) and haplotype II (AR2), which may represent two altitudinal ecotypes. The direct threats identified were related to recreation activities, road construction and fire. The subpopulations of the plant are regulated by density and depend on fecundity and on the soil seedbank while their persistence depends mainly on habitat availability. Low genetic diversity combined with small population size and a possible reduction in fitness suggest increased susceptibility to loss of genetic variation. The overall results suggest that ex situ conservation in a seed bank, and in situ conservation in the form of population restoration, are suitable conservation measures and the study of the different aspects of the species’ biology has provided the data required for their implementation.
Antonelou MH, Kriebardis AG, Stamoulis KE, Trougakos IP, Papassideri IS (2011). Apolipoprotein J/Clusterin is a novel structural component of human erythrocytes and a biomarker of cellular stress and senescence. PLoS ONE 6(10): e26032.
Abstract: Background: Secretory Apolipoprotein J/Clusterin (sCLU) is a ubiquitously expressed chaperone that has been functionally implicated in several pathological conditions of increased oxidative injury, including aging. Nevertheless, the biological role of sCLU in red blood cells (RBCs) remained largely unknown. In the current study we identified sCLU as a component of human RBCs and we undertook a detailed analysis of its cellular topology. Moreover, we studied the erythrocytic membrane sCLU content during organismal aging, in conditions of increased organismal stress and accelerated RBCs senescence, as well as during physiological in vivo cellular senescence. Methodology/Principal Findings: By using a combination of molecular, biochemical and high resolution microscopical methods we found that sCLU is a novel structural component of RBCs extra- and intracellular plasma membrane and cytosol. We observed that the RBCs membrane-associated sCLU decreases during organismal aging or exposure to acute stress (e.g. smoking), in patients with congenital hemolytic anemia, as well as during RBCs in vivo senescence. In all cases, sCLU reduction paralleled the expression of typical cellular senescence, redox imbalance and erythrophagocytosis markers which are also indicative of the senescence- and oxidative stress-mediated RBCs membrane vesiculation. Conclusions/Significance: We propose that sCLU at the mature RBCs is not a silent remnant of the erythroid precursors, but an active component being functionally implicated in the signalling mechanisms of cellular senescence and oxidative stress responses in both healthy and diseased organism. The reduced sCLU protein levels in the RBCs membrane following cell exposure to various endogenous or exogenous stressors closely correlates to the levels of cellular senescence and redox imbalance markers, suggesting the usefulness of sCLU as a sensitive biomarker of senescence and cellular stress.
Antonelou MH, Kriebardis AG, Stamoulis KE, Trougakos IP, Papassideri IS (2011). Apolipoprotein J/Clusterin in human erythrocytes is involved in the molecular process of defected material disposal during vesiculation. PLoS ONE 6(10): e26033.
Abstract: Background: We have showed that secretory Apolipoprotein J/Clusterin (sCLU) is down-regulated in senescent, stressed or diseased red blood cells (RBCs). It was hypothesized that sCLU loss relates to RBCs vesiculation, a mechanism that removes erythrocyte membrane patches containing defective or potentially harmful components. Methodology/Principal Findings: To investigate this issue we employed a combination of biochemical and microscopical approaches in freshly prepared RBCs or RBCs stored under standard blood bank conditions, an in vitro model system of cellular aging. We found that sCLU is effectively exocytosed in vivo during membrane vesiculation of freshly prepared RBCs. In support, the RBCs’ sCLU content was progressively reduced during RBCs ex vivo maturation and senescence under cold storage due to its selective exocytosis in membrane vesicles. A range of typical vesicular components, also involved in RBCs senescence, like Band 3, CD59, hemoglobin and carbonylated membrane proteins were found to physically interact with sCLU. Conclusions/Significance: The maturation of RBCs is associated with a progressive loss of sCLU. We propose that sCLU is functionally involved in the disposal of oxidized/defected material through RBCs vesiculation. This process most probably takes place through sCLU interaction with RBCs membrane proteins that are implicit vesicular components. Therefore, sCLU represents a pro-survival factor acting for the postponement of the untimely clearance of RBCs.
Antonelou MH, Kriebardis AG, Velentzas AD, Kokkalis AC, Georgakopoulou SC, Papassideri IS (2011). Oxidative stress-associated shape transformation and membrane proteome remodeling in erythrocytes of end stage renal disease patients on hemodialysis. J Proteomics. (in press)
Abstract: This study was designed to evaluate the oxidative stress status of erythrocytes and its association with cellular ultrastructure and membrane proteome modifications in patients with end stage renal disease (ESRD) on hemodialysis (HD). For that purpose, we studied red blood cells' (RBCs) modifications in twelve non-diabetic ESRD patients that were responsive in erythropoietin therapy. Intracellular ROS levels were measured by fluorometry, RBCs ultra-structure was examined by electron microscopy, while the membrane proteome by electrophoresis and immunoblotting. Compared to the healthy subjects, the uremic RBCs exhibited significantly increased ROS accumulation. Dialysis partially ameliorated the basal ROS levels but triggered cellular sensitivity to exogenous oxidative stimuli. Common membrane modifications involved loss, aggregation, fragmentation and carbonylation of critical components as well as over-expression of stress markers. HD significantly contributed to membrane proteome remodeling, especially for aquaporin-1, peroxiredoxin-2 and ubiquitinated proteins. The intracellular redox status and the closely associated membrane modifications seemed to be related to membrane instability, loss of surface area through vesiculation, echinocytosis and stomatocytosis. Our data evinced a network of interactions among the uremic toxins, the RBCs membrane composition and the cellular shape modifications in ESRD, which is developed around a core of oxidative provocations and cellular responses.
Arianoutsou M., Koukoulas S., Kazanis D. (2011) Evaluating Post-Fire Forest Resilience Using GIS and Multi-Criteria Analysis: An Example from Cape Sounion National Park, Greece. Environmental Management (in press - DOI 10.1007/s00267-011-9614-7)
Abstract: Forest fires are one of the major causes of ecological disturbance in the mediterranean climate ecosystems of the world. Despite the fact that a lot of resources have been invested in fire prevention and suppression, the number of fires occurring in the Mediterranean Basin in the recent decades has continued to markedly increase. The understanding of the relationship between landscape and fire lies, among others, in the identification of the system’s post-fire resilience. In our study, ecological and landscape data are integrated with decision-support techniques in a Geographic Information Systems (GIS) framework to evaluate the risk of losing post-fire resilience in Pinus halepensis forests, using Cape Sounion National Park, Central Greece, as a pilot case. The multi-criteria decision support approach has been used to synthesize both bioindicators (woody cover, pine density, legume cover and relative species richness and annual colonizers) and geoindicators (fire history, parent material, and slope inclination) in order to rank the landscape components. Judgments related to the significance of each factor were incorporated within the weights coefficients and then integrated into the multicriteria rule to map the risk index. Sensitivity analysis was very critical for assessing the contribution of each factor and the sensitivity to subjective weight judgments to the final output. The results of this study include a final ranking map of the risk of losing resilience, which is very useful in identifying the ‘‘risk hotspots’’, where post-fire management measures should be applied in priority.
Bitsikas V, Karachaliou M, Gournas C, Diallinas G. (2011) Hypertonic conditions trigger transient plasmolysis, growth arrest and blockage of transporter endocytosis in Aspergillus nidulans and Saccharomyces cerevisiae. Mol Membr Biol. 28(1):54-68.
Abstract: By using Aspergillus nidulans strains expressing functional GFP-tagged transporters under hypertonic conditions, we noticed the rapid appearance of cortical, relatively static, fluorescent patches (0.5-2.3 μm). These patches do not correspond to transporter microdomains as they co-localize with other plasma membrane-associated molecules, such as the pleckstrin homology (PH) domain and the SsoA t-Snare, or the lipophilic markers FM4-64 and filipin. In addition, they do not show characteristics of lipid rafts, MCCs or other membrane microdomains. Deconvoluted microscopic images showed that fluorescent patches correspond to plasma membrane invaginations. Transporters remain fully active during this phenomenon of localized plasmolysis. Plasmolysis was however associated with reduced growth rate and a dramatic blockage in transporter and FM4-64 endocytosis. These phenomena are transient and rapidly reversible upon wash-out of hypertonic media. Based on the observation that block in endocytosis by hypertonic treatment altered dramatically the cellular localization of tropomyosin (GFP-TpmA), although it did not affect the cortical appearance of upstream (SlaB-GFP) or downstream (AbpA-mRFP) endocytic components, we conclude that hypertonicity modifies actin dynamics and thus acts indirectly on endocytosis. This was further supported by the effect of latrunculin B, an actin depolymerization agent, on endocytosis. We show that the phenomena observed in A. nidulans also occur in Saccharomyces cerevisiae, suggesting that they constitute basic homeostatic responses of ascomycetes to hypertonic shock. Finally, our work shows that hypertonic treatments can be used as physiological tools to study the endocytic down-regulation of transporters in A. nidulans, as non-conditional genetic blocks affecting endocytic internalization are lethal or severely debilitating.
Chaideftou E., Thanos C.A., Bergmeier E., Kallimanis A., Dimopoulos P. (2011). The herb layer restoration potential of the soil seed bank in an overgrazed oak forest. Journal of Biological Research 15, 47-57.
Abstract: We investigated the potential contribution of the persistent soil seed bank in post-disturbance restoration of the herb layer in a long-term overgrazed, mixed oak forest (NW Greece). We examined the impacts of grazing on plant richness and density in the soil seed bank in regard to the different dispersal and life strategy types of the herb layer taxa. Soil seed bank was qualitatively and quantitatively analyzed and contrasting plant guilds were defined according to life strategy type and dispersal mode. Soil seed bank differences between a) the upper and lower soil layers and b) plant functional guild pairs (ruderals vs. non ruderals, including typical forest taxa, and physically- vs. animal-dispersed plants) were statistically tested in overgrazed and sporadically grazed plots. Moreover, correlations in soil seed bank species dominance between overgrazed and sporadically grazed plots were examined by Spearman’s Rank correlation. The majority of seeds were found in the upper (0-5 cm) soil layer. Seed density in the deeper (5-10 cm) soil layer was rather poor and did not differ significantly between overgrazed and sporadically grazed plots. In the upper soil layer, both seed density and plant species richness were significantly lower in the overgrazed plots. Overgrazing reduced both species richness and seed density of non-ruderal species in general and typical forest herbs in particular, while it did not affect ruderal species richness and density. Plant species richness and seed density of animal-dispersed taxa were reduced by overgrazing while physically-dispersed species were not affected; it is therefore concluded that large herds of grazers fenced in relatively small areas cannot act as efficient dispersal vectors of the former species. Our findings suggest that, upon cessation of grazing, the soil seed bank is rather inadequate to restore the herb layer of overgrazed forest sites.
Chatzigeorgiou, K.S., Sergentanis, T.N., Tsiodras, S., Hamodrakas, S.J., Bagos, P.G. (2011). Phoenix 100 versus Vitek 2 in the Identification of Gram-Positive and Gram-Negative Bacteria: a Comprehensive Meta-Analysis. J Clin Microbiol., 49(9):3284-91.
Abstract: Phoenix 100 and Vitek 2 (operating with the current colorimetric cards) are commonly used in hospital laboratories for rapid identification of microorganisms. The present meta-analysis aims to evaluate and compare their performance on Gram-positive and Gram-negative bacteria. The MEDLINE database was searched up to October 2010 for the retrieval of relevant articles. Pooled correct identification rates were derived from random-effects models, using the arcsine transformation. Separate analyses were conducted at the genus and species levels; subanalyses and meta-regression were undertaken to reveal meaningful system- and study-related modifiers. A total of 29 (6,635 isolates) and 19 (4,363 isolates) articles were eligible for Phoenix and colorimetric Vitek 2, respectively. No significant differences were observed between Phoenix and Vitek 2 either at the genus (97.70% versus 97.59%, P = 0.919) or the species (92.51% versus 88.77%, P = 0.149) level. Studies conducted with conventional comparator methods tended to report significantly better results compared to those using molecular reference techniques. Speciation of Staphylococcus aureus was significantly more accurate in comparison to coagulase-negative staphylococci by both Phoenix (99.78% versus 88.42%, P < 0.00001) and Vitek 2 (98.22% versus 91.89%, P = 0.043). Vitek 2 also reached higher correct identification rates for Gram-negative fermenters versus nonfermenters at the genus (99.60% versus 95.90%, P = 0.004) and the species (97.42% versus 84.85%, P = 0.003) level. In conclusion, the accuracy of both systems seems modified by underlying sample- and comparator method-related parameters. Future simultaneous assessment of the instruments against molecular comparator procedures may facilitate interpretation of the current observations.
Christodoulou A, Kostakis IK, Kourafalos V, Pouli N, Marakos P, Trougakos IP, Tsitsilonis OE (2011). Design, synthesis and antiproliferative activity of novel aminosubstituted benzothiopyranoisoindoles. Bioorg Med Chem Lett. 21(10):3110-2. Epub 2011 Mar 11.
Abstract: The synthesis of a number of new benzothiopyrano[4,3,2-cd]isoindole aminoderivatives designed as structural analogues of the key metabolite of the anticancer agent Ledacrine (nitracrine) and their in vitro cytotoxic activity evaluation against HCT-116, MES-SA, and MES-SA/Dx cancer cell lines is reported. The majority of the derivatives possessed noticeable cytotoxicity in a low μM range indicating an interesting structure-activity relationship.
Fandridis E, Apergis G, Korres DS, Nikolopoulos K, Zoubos AB, Papassideri I, Trougakos IP. (2011). Increased expression levels of apolipoprotein J/clusterin during primary osteoarthritis. In Vivo 25(5):745-9.
Abstract: Osteoarthritis (OA) is a slowly progressive degenerative joint disease that is associated with joint space narrowing, osteophyte formation and subchondral sclerosis. Despite extensive effort actual breakthroughs in the field of genetic or biochemical biomarkers of OA are limited. As secretory apolipoprotein J/clusterin (sCLU) has been implicated in both inflammatory and apoptotic molecular processes which contribute to the OA phenotype, the sCLU concentration in human serum and synovial fluid during advanced primary knee and hip OA was analysed. Elevated sCLU protein levels were shown in these two biological fluids. sCLU mRNA expression was also studied in normal cartilage and in advanced primary knee and hip OA samples. A significant up-regulation of sCLU mRNA expression (~25-fold) was found in samples collected from the tibial bone that was osteotomized during total knee arthroplasty in patients with primary knee OA, as compared to healthy tissue samples collected from the femoral head of macroscopically normal cartilage during the surgical treatment of subcapital fractures. By studying sCLU mRNA expression levels in samples collected during total hip arthroplasty in patients with advanced primary hip OA, an additional up-regulation of the sCLU mRNA expression (~4-fold), as compared to advanced primary knee OA, was found. Taken together, these observations indicate that the sCLU protein or mRNA expression level may be of a significant diagnostic and/or prognostic value during OA progression.
Fragopoulou AF, Samara A, Antonelou MH, Xanthopoulou A, Papadopoulou A, Vougas K, Koutsogiannopoulou E, Anastasiadou E, Stravopodis DJ, Tsangaris GT, Margaritis LH. (2011). Brain proteome response following whole body exposure of mice to mobile or wireless DECT phone radiation. Electromagnetic Biology and Medicine.
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 hours daily for 8 months, the second group was exposed to a wireless DECT base at a SAR level range of 0.012-0.028 W/kg for 8hrs/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, 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 translationally might explain human health hazards reported so far, such as headaches, sleep disturbance, fatigue, memory deficits and brain tumour long-term induction under similar exposure conditions.
Gournas C, Oestreicher N, Amillis S, Diallinas G, Scazzocchio C. (2011). Completing the purine utilisation pathway of Aspergillus nidulans. Fungal Genet Biol. [Epub ahead of print PMID:21419234]
Abstract: We have previously identified by classical genetics and biochemistry, all the genes of Aspergillus nidulans predicted to be involved in purine utilisation, together with cognate regulatory genes and one gene encoding a novel xanthine hydroxylation activity. In this article we complete the description of the purine utilisation pathway with the identification of the two genes (uaX and uaW) encoding the enzymes catalysing the conversion of the product of urate oxidation by urate oxidase, 5-hydroxyisourate, to optically active allantoin. The identification of these additional genes confirms the complete absence of clustering of the genes involved in purine utilisation in A. nidulans.
Hamodrakas, S.J. (2011). Protein aggregation and amyloid fibril formation prediction software from primary sequence: towards controlling the formation of bacterial inclusion bodies. FEBS J., 278(14): 2428–2435.
Abstract: Proteins might aggregate into ordered or amorphous structures, utilizing relatively short sequence stretches, usually organized in β-sheet-like assemblies. Here, we attempt to list all available software, developed during the last decade or so, for the prediction of such aggregation-prone stretches from protein primary structure, without distinguishing whether these algorithms predict amino acid sequences destined to be involved in ordered fibrillar amyloids or amorphous aggregates. The results of application of four of these programs on 23 proteins related to amyloidoses are compared. Because protein aggregation during protein production in bacterial cell factories has been shown to resemble amyloid formation, the algorithms might become useful tools to improve the solubility of recombinant proteins and for screening therapeutic approaches against amyloidoses under conditions that mimic physiologically relevant environments. One such example is given.
Iconomidou, V.A., Cordopatis, P., Hoenger, A., Hamodrakas, S.J. (2011). The silkmoth eggshell as a natural amyloid shield for the safe development of insect oocyte and embryo: Insights from studies of silkmoth chorion protein peptide-analogues of the B family. Peptide Science,Biopolymers 96 (6): 723-733
Abstract: Silkmoth chorion is the major component of the silkmoth eggshell. The proteins that constitute more than 95% of its dry mass have remarkable mechanical and physicochemical properties forming a protective natural shield for the oocyte and the developing embryo from a wide range of environmental hazards. Peptide-analogues of the central conservative domain of the two major families of silkmoth chorion proteins, the A’s and the B’s, form amyloid fibrils under a variety of conditions, which prompted us to propose, ten years ago, that silkmoth chorion is an amyloid with protective properties. Following our finding, a number of studies verified the existence of several functional amyloids. In this study, we designed, synthesized and studied two peptide-analogues of the central conservative domain of the B family of silkmoth chorion proteins, and we present experimental results, which show: (a) that the amyloidogenic properties of silkmoth chorion peptides are encoded into the tandemly repeating hexapeptides comprising the central domain of silkmoth chorion proteins, confirming our previous findings from peptide analogues of the A family of chorion proteins, and, (b) they suggest how silkmoth chorion proteins of the B family self-assemble in vivo, for the formation of the helicoidal architecture of silkmoth chorion.
Iconomidou, V.A., Pheida, D., Hamodraka, E.S., Antony, C., Hoenger, A., Hamodrakas, S.J. (2011). An amyloidogenic determinant in N-terminal pro-brain natriuretic peptide (NT-proBNP): Implications for cardiac amyloidoses Biopolymers. Peptide Science
Abstract: Deposition of amyloid in the atria (isolated atrial/cardiac amyloid) is fairly common in the ageing heart. It consists of amyloid fibrils, formed both by atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) and the precursor molecule of ANP, proANP. This study examines whether amyloidogenic determinants (short peptides/amyloid forming favouring regions) exist in the sequence of NT-proBNP, the N-terminal part of proBNP, and if these determinants form amyloid-like fibrils in vitro. We have predicted a possible amyloidogenic determinant in the sequence of the NT-proBNP and we conclusively show, after its synthesis, that it forms amyloid-like fibrils in-vitro, utilizing transmission electron microscopy, X-ray diffraction, ATR FT-IR and polarizing microscopy. Thus, in this study, a possible biological role is attributed, for the first time, to a certain, specific, part of this important cardiac prohormone/natriuretic peptide, which acts as an important biomarker indicative of heart failure. Its possible direct involvement in isolated cardiac amyloidosis, atrial fibrillation and other types of cardiac amyloidoses is indicated and discussed. Since these cardiac hormones and their prohormones play key roles in cardiovascular homeostasis through natriuresis, diuresis, vasorelaxation, and inhibition of renin and aldosterone secretion (pathophysiology of hypertension and cardiovascular regulation), we also try to suggest these specific, short, peptides as possible future structural targets of efforts towards inhibiting formation of natriuretic peptide(s) amyloid.
Kallimanis A, Labutti KM, Lapidus A, Clum A, Lykidis A, Mavromatis K, Pagani I, Liolios K, Ivanova N, Goodwin L, Pitluck S, Chen A, Palaniappan K, Markowitz V, Bristow J, Velentzas AD, Perisynakis A, Ouzounis CC, Kyrpides NC, Koukkou AI, Drainas C. (2011) Complete genome sequence of Arthrobacter phenanthrenivorans type strain (Sphe3). Stand Genomic Sci. 29;4(2):123-30.
Abstract: Arthrobacter phenanthrenivorans is the type species of the genus, and is able to metabolize phenanthrene as a sole source of carbon and energy. A. phenanthrenivorans is an aerobic, non-motile, and Gram-positive bacterium, exhibiting a rod-coccus growth cycle which was originally isolated from a creosote polluted site in Epirus, Greece. Here we describe the features of this organism, together with the complete genome sequence, and annotation.
Kazanis Dimitris, Xanthopoulos Gavriil, Arianoutsou Margarita (2011). Understorey fuel load estimation along two post-fire chronosequences of Pinus halepensis Mill. forests in Central Greece. J For Res (2012) 17:105–109
Abstract: Pinus halepensis forests are among the forest ecosystems in the Mediterranean Basin most affected by fire. Their distribution across lowland areas, in particular along the wildland–urban interface, increases the need to understand their ecology and responses to fire regime for their effective management. Apart from the extremely flammable tree layer, in several stands of these forests there is an increased fuel load attributed to the well-developed understorey of evergreen sclerophyllous shrubs. Taking into consideration that, in contrast with the long period required for full development of post-fire-regenerating pines, these shrubs resprout vigorously within the first postfire weeks, it is important to explore the temporal trend of fuel accumulation to determine the risk of a second fire across a burned landscape. Two post-fire chronosequences of, in total, 12 P. halepensis stands were considered for sampling in Central Greece. The first chronosequence corresponds to pine stands characterized by the dominance of evergreen sclerophyllous shrubs in the understorey (Type 1) whereas the second chronosequence corresponds to pine stands where the cover of such shrubs was lower (Type 2). This study helps in understanding the fuel dynamics according to the type of P. halepensis forest stand and to anticipate future biomass growth. The proposed equations are simple tools, enabling land managers to estimate understorey total fuel load easily by visually recording the cover and height of the evergreen sclerophyllous shrub component, to justify understorey fuel reduction measures.
Koussoulakou DS, Margaritis LH, Koussoulakos SL. (2011). Antagonists of retinoic acid and BMP4 affect fetal mouse osteogenesis and odontoblast differentiation..Pathophysiology, 18(2):103-109.
Abstract: Retinoic acid and bone morphogenetic protein (BMP4) are endogenous factors indispensable for the physiological development of vertebrates. The proximate aim of the present study was to investigate whether the natural compound citral (a retinoic acid synthesis inhibitor) and a monoclonal, anti-BMP4 antibody, administered to pregnant mice affect in the fetuses cranial osteogenesis and odontoblast differentiation. The present investigation was motivated by the fact that, retinoic acid inhibitors and BMP4 neutralizers may frequently contact human tissues (both intentional and unintentional, and/or unconsciously) inducing unanticipated effects. Our ultimate goal is the prevention of side effects and, future clinical implementation of the results. To this end, pregnant, white mice (balb-c Mus musculus) were intra-abdominally injected with either citral or anti-BMP4 antibody at the 9th gestational day. Newborns were processed within 5h, postnatal. Results were evaluated (a) macroscopically, (b) stereoscopically, following histochemical double staining of cartilage and osseous tissues and, (c) microscopically after (c(1)) histological staining of paraffin sections, and, (c(2)) immunohistochemical detection of apoptosis. Data indicate that in vivo administration of citral (biomimicking hypovitaminosis A) caused restriction/retardation of cranial chondrogenesis and osteogenesis. Apoptosis was not detected in teeth tissues. In vivo administration of anti-BMP4 antibody resulted in a transitory interference with the normal course of odontoblast differentiation and the production of pre-dentin, whereas, delay in the ossification also included the alveoli. Animals inspected in adulthood displayed a fairly normal phenotype. It is concluded that those two substances, under their concentrations experienced, are quite safe for the public.
Lampidonis AD, Rogdakis E, Voutsinas GE, Stravopodis DJ. (2011). The resurgence of Hormone-Sensitive Lipase (HSL) in mammalian lipolysis.. Gene. 15;477(1-2):1-11.
Abstract: The ability to store energy in the form of energy-dense triacylglycerol and to mobilize these stores rapidly during periods of low carbohydrate availability or throughout the strong metabolic demand is a highly conserved process, absolutely essential for survival. In the industrialized world the regulation of this pathway is viewed as an important therapeutic target for disease prevention. Adipose tissue lipolysis is a catabolic process leading to the breakdown of triacylglycerols stored in fat cells, and release of fatty acids and glycerol. Mobilization of adipose tissue fat is mediated by the MGL, HSL and ATGL, similarly functioning enzymes. ATGL initiates lipolysis followed by the actions of HSL on diacylglycerol, and MGL on monoacylglycerol. HSL is regulated by reversible phosphorylation on five critical residues. Phosphorylation alone, however, is not enough to activate HSL. Probably, conformational alterations and a translocation from the cytoplasm to lipid droplets are also involved. In accordance, Perilipin functions as a master regulator of lipolysis, protecting or exposing the triacylglycerol core of a lipid droplet to lipases. The prototype processes of hormonal lipolytic control are the β-adrenergic stimulation and suppression by insulin, both of which affect cytoplasmic cyclic AMP levels. Lipolysis in adipocytes is an important process in the management of body energy reserves. Its deregulation may contribute to the symptoms of type 2 diabetes mellitus and other pathological situations. We, herein, discuss the metabolic regulation and function of lipases mediating mammalian lipolysis with a focus on HSL, quoting newly identified members of the lipolytic proteome.
Leskov KS, Araki S, Lavik JP, Gomez J, Gama V, Gonos ES, Trougakos IP, Matsuyama S, Boothman DA. (2011) Crm1-mediated regulation of nuclear clusterin (nCLU), An Ionizing radiation-stimulated, bax-dependent pro-death factor..J Biol Chem.
Abstract: Expression of the clusterin (CLU) gene results in the synthesis of a conventional secretory isoform set (pre- and mature secretory clusterin proteins, psCLU/sCLU), as well as another set of intracellular isoforms, appearing in the cytoplasm (pre-nuclear CLU, pnCLU) in basal cells and in the nucleus as an ~55 kDa mature nuclear clusterin (nCLU) form. These two isoform sets have opposing cell functions: pro-survival and pro-death, respectively. Although much is known about the regulation and function of sCLU as a pro-survival factor, the regulation and function of endogenous nCLU in cell death is relatively unexplored. Here, we show that depletion of endogenous nCLU protein using siRNA specific to its truncated mRNA increased clonogenic survival of ionizing radiation (IR)-exposed cells. nCLU-mediated apoptosis was Bax-dependent, and lethality correlated with accumulation of mature nCLU protein. nCLU accumulation was regulated by CRM1, since binding between CRM1 and nCLU proteins was significantly diminished by leptomycin B (LMB), and nuclear levels of nCLU protein was significantly enhanced by LMB and IR co-treatment. Moreover, LMB treatment significantly enhanced IR-induced nCLU-mediated cell death responses. Importantly, bax-/- and bax-/-/bak-/- double knockout cells were resistant to nCLU-mediated cell death, while bak-/- or wild-type bax+/+/bak+/+ cells were hypersensitive. The regulation of nCLU by CRM1 nuclear export/import may explain recent clinical results showing that highly malignant tumors have lost the ability to accumulate nCLU levels, thereby avoiding growth inhibition and cell death.
Meletiou-Christou M.S., Banilas M.S., Bardis C., Rhizopoulou S. (2011) - Plant biomonitoring: Impact of urban environment on seasonal dynamics of storage substances and chlorophylls of oleander. Global NEST Journal, Vol 13, No 4, pp 395-404.
Abstract: In the present study seasonal changes of chlorophyll content and storage substances related to the metabolic response of the widespread, evergreen plant oleander (Nerium oleander) to air pollution were investigated. Mature leaves of oleander shrubs, grown at five sites of differing levels of air pollution in the center and the suburbs of the Athens Metropolitan area, were examined during the course of a year. Soluble sugars, starch and total lipid content of the leaves showed a peak at the end of the cold season, while a decline was detected during the main growth period. Leaf chlorophyll content was increased during spring. It seems likely that the level of air pollution in Athens did not affect the concentration and the seasonal pattern of storage substances at the leaf level. Elevated chlorophyll content was estimated in the polluted with oxides of nitrogen sites. In contrast, leaf chlorophyll content declined in sites with ozone pollution.
Moreira F., Viedma O., Arianoutsou M., Curt T., Koutsias N., Rigolot E., Barbati A., Corona P., Vaz P., Xanthopoulos G., Mouillot F., Bilgili E. (2011) Landscape - wildfire interactions in southern Europe: Implications for landscape management. Journal of Environmental Management, 92, 2389-2402.
Abstract: Every year approximately half a million hectares of land are burned by wildfires in southern Europe, causing large ecological and socio-economic impacts. Climate and land use changes in the last decades have increased fire risk and danger. In this paper we review the available scientific knowledge on the relationships between landscape and wildfires in the Mediterranean region, with a focus on its application for defining landscape management guidelines and policies that could be adopted in order to promote landscapes with lower fire hazard. The main findings are that (1) socio-economic drivers have favoured land cover changes contributing to increasing fire hazard in the last decades, (2) large wildfires are becoming more frequent, (3) increased fire frequency is promoting homogeneous landscapes covered by fire-prone shrublands; (4) landscape planning to reduce fuel loads may be successful only if fire weather conditions are not extreme. The challenges to address these problems and the policy and landscape management responses that should be adopted are discussed, along with major knowledge gaps.
Mpakou VE, Velentzas AD, Velentzas PD, Margaritis LH, Stravopodis DJ, Papassideri IS. (2011) Programmed cell death of the ovarian nurse cells during oogenesis of the ladybird beetle Adalia bipunctata (Coleoptera: Coccinellidae). .Dev Growth Differ. 53(6):804-15.
Abstract: Programmed cell death (PCD) is an evolutionary conserved and genetically regulated form of cell death, in which the cell plays an active role in its own demise. It is widely recognized that PCD can be morphologically classified into three major types: type I, known as apoptosis, type II, called autophagy, and type III, specified as cytoplasmic cell death. So far, PCD has been morphologically analyzed in certain model insect species of the meroistic polytrophic ovary-type, but has never been examined before in insects carrying meroistic telotrophic ovaries. In the present study, we attempted to thoroughly describe the three different types (I, II and III) of PCD occurring during oogenesis in the meroistic telotrophic ovary of the Coleoptera species Adalia bipunctata, at different developmental ages of the adult female insects. We reveal that in the ladybird beetle A. bipunctata, the ovarian tropharia undergo age-dependent forms of apoptotic, autophagic and cytoplasmic (paraptotic-like) cell death, which seem to operate in a rather synergistic fashion, in accordance with previous observations in Diptera and Lepidoptera species. Furthermore, we herein demonstrate the occurrence of morphogenetically abnormal ovarioles in A. bipunctata female insects. These atretic ovarioles collapse and die through a PCD-mediated process that is characterized by the combined activation of all three types of PCD. Conclusively, the distinct cell death programs (I, II and III) specifically engaged during oogenesis of A. bipunctata provide strong evidence for the structural and functional conserved nature of PCD during insect evolution among meroistic telotrophic and meroistic polytrophic ovary-type insects.
Ntzouni MP, Stamatakis A, Stylianopoulou F, Margaritis LH. (2011). Short-term memory in mice is affected by mobile phone radiation. . Pathophysiology. 18(3):193-9.
Abstract: The effects of mobile phone electromagnetic fields (EMFs) were studied on a non-spatial memory task (Object Recognition Task - ORT) that requires entorhinal cortex function. The task was applied to three groups of mice Mus musculus C57BL/6 (exposed, sham-exposed and control) combined with 3 different radiation exposure protocols. In the first protocol designated "acute exposure", mice 45 days old (PND45 - postnatal day 45) were exposed to mobile phone (MP) radiation (SAR value 0.22W/kg) during the habituation, the training and the test sessions of the ORT, but not during the 10min inter-trial interval (ITI) where consolidation of stored object information takes place. On the second protocol designated "chronic exposure-I", the same mice were exposed for 17 days for 90min/per day starting at PND55 to the same MP radiation. ORT recognition memory was performed at PND72 with radiation present only during the ITI phase. In the third protocol designated "chronic exposure-II", mice continued to be exposed daily under the same conditions up to PND86 having received radiation for 31 days. One day later the ORT test was performed without irradiation present in any of the sessions. The ORT-derived discrimination indices in all three exposure protocols revealed a major effect on the "chronic exposure-I" suggesting a possible severe interaction of EMF with the consolidation phase of recognition memory processes. This may imply that the primary EMF target may be the information transfer pathway connecting the entorhinal-parahippocampal regions which participate in the ORT memory task.
Politi Patrizia-I, Georghiou Kyriacos, Arianoutsou Margarita (2011). Reproductive biology of Abies cephalonica Loudon in Mount Aenos National Park, Cephalonia, Greece. Trees Structure & Function (in press - DOI 10.1007/s00468-011-0542-1)
Abstract: The reproductive biology of the endemic to Greece Abies cephalonica Loudon, including the phenology of the reproductive life cycle, cone production in relation to plant age and the required seed germination conditions, was studied. All individuals growing within 20 permanent plots of 100 m2 each established in 11 different locations covering the entire strictly protected area of Mount Aenos National Park (Cephalonia) were monitored over a period of 4 years. The cones are formed on the upper part of the previous year’s branches, mostly at the upper crown half of the reproductive individuals (over 53 years old). Female flowers are pollinated in spring and cone maturation lasts until the beginning of autumn, when seed dispersal occurs. The annual production of cones per individual varied significantly, revealing masting behavior for this tree. This behavior was also expressed in the number of trees producing cones, as well as the percentage of sound seeds per cone. A significant difference in the mass and the length of the cones between the years of low and high cone production was observed, being higher in the years of massive cone production. Similar germination percentages were observed in full darkness or under ‘‘canopy light’’ and ‘‘sun light’’, provided that the seeds were previously stratified for 6 weeks. It is concluded that A. cephalonica exhibits plasticity expressed in its reproductive behavior for alternating years of high to low cone production and in its seed germination for an array of habitat light conditions.
Samara A, Sarri Y, Stravopodis D, Tzanetakis GN, Kontakiotis EG, Anastasiadou E. (2011). A comparative study of the effects of three root-end filling materials on proliferation and adherence of human periodontal ligament fibroblasts. . J Endod. 37(6):865-70.
Abstract: INTRODUCTION: The present in vitro study was conducted with the aim of evaluating and comparing the cytotoxic effects of three root-end filling materials, ProRoot mineral trioxide aggregate (ProRoot MTA; Dentsply Tulsa Dental, Memphis, TN), MTA Angelus (Angelus, Londrina, Brazil), and a modified zinc oxide-eugenol cement (Super-EBA; Bosworth Co, Skokie, IL) on human periodontal ligament (PDL) fibroblasts. METHODS: PDL cells were cultured in an mineral trioxide aggregate (MTA)- or a Super-EBA-conditioned medium to assess the viability as determined by the trypan blue exclusion assay. The proliferation of the cells was recorded, and the cellular morphology was observed by confocal microscopy. Moreover, PDL cell aggregates were cultured on the substrate surfaces to assess cell adhesion. RESULTS: ProRoot MTA was found to be the most biocompatible material, whereas Super-EBA was found to be the most cytotoxic material because it significantly inhibited the cell growth and adherence on its. In the presence of ProRoot MTA, the PDL cell proliferation was almost unaltered. MTA Angelus was found to be more cytotoxic than ProRoot MTA, offering, however, excellent scaffold properties for the adhesion of cell aggregates. CONCLUSIONS: Under the conditions of the present study, it seems that commercially available forms of MTA may behave in different ways regarding their proliferative effect on human PDL fibroblasts. ProRoot MTA appears to be the most biocompatible of the three tested materials when considering use for root-end endodontic microsurgery.
Stravopodis DJ, Karkoulis PK, Konstantakou EG, Melachroinou S, Thanasopoulou A, Aravantinos G, Margaritis LH, Anastasiadou E, Voutsinas GE. (2011). Thymidylate synthase inhibition induces p53-dependent and p53-independent apoptotic responses in human urinary bladder cancer cells. . J Cancer Res Clin Oncol. 137(2):359-74.
Abstract: PURPOSE: In search for more effective clinical protocols, the antimetabolite drug 5-fluorouracil (5-FU) has been successfully included in new regimens of bladder cancer combination chemotherapy. In the present study, we have investigated the effects of 5-FU treatment on apoptosis induction in wild-type and mutant p53 urinary bladder cancer cells. METHODS: We have used MTT-based assays, FACS analysis, Western blotting and semi-quantitative RT-PCR in RT4 and RT112 (grade I, wild-type p53), as well as in T24 (grade III, mutant p53) and TCCSUP (grade IV, mutant p53) human urinary bladder cancer cell lines. RESULTS: In the urothelial bladder cancer cell lines RT4 and T24, 5-FU-induced TS inhibition proved to be associated with cell type-dependent (a) sensitivity to the drug, (b) Caspase-mediated apoptosis, (c) p53 stabilization and activation, as well as Rb phosphorylation and E2F1 expression and (d) transcriptional regulation of p53 target genes and their cognate proteins, while an E2F-dependent transcriptional network did not seem to be critically engaged in such type of responses. CONCLUSIONS: We have shown that in the wild-type p53 context of RT4 cells, 5-FU-triggered apoptosis was prominently efficient and mainly regulated by p53-dependent mechanisms, whereas the mutant p53 environment of T24 cells was able to provide notable levels of resistance to apoptosis, basically ascribed to E2F-independent, and still unidentified, pathways. Nevertheless, the differential vulnerability of RT4 and T24 cells to 5-FU administration could also be associated with cell-type-specific transcriptional expression patterns of certain genes critically involved in 5-FU metabolism.
Srivastava, A.K., Iconomidou, V.A., Chryssikos, G.D., Gionis, V., Kumar, K., Hamodrakas, S.J. (2011). Secondary structure of chorion proteins of the Lepidoptera Pericallia ricini and Ariadne merione by ATR FT-IR and micro-Raman spectroscopy. . Int J Biol Macromol, 49(3): 317-22.
Abstract: The gross morphological features of the eggs and eggshells (chorions) of two Lepidoptera species, Pericallia ricini and Ariadne merione were revealed for the first time by scanning and transmission electron microscopy. These two insect pests are extremely serious threats for many crops, mainly in India, but also in several other regions of the world. Micro-Raman and ATR FT-IR spectroscopy were also applied to study in detail the secondary structure of the eggshell (chorion) proteins of these Lepidoptera species. Both techniques indicate that the two species have nearly identical conformations of their chorion proteins with abundant antiparallel β-pleated sheet. These results are in support of our previous findings that the helicoidal architecture of the proteinaceous chorion of Lepidoptera and fishes is dictated by a common molecular denominator, the antiparallel β-pleated sheet secondary structure.
Tsirigos, K.D., Bagos, P.G. and Hamodrakas, S.J. (2011). OMPdb: A database of ß-barrel outer membrane proteins from Gram negative bacteria. . Nucleic Acids Res., 39(Database issue): D324-31.
Abstract: We describe here OMPdb, which is currently the most complete and comprehensive collection of integral β-barrel outer membrane proteins from Gram-negative bacteria. The database currently contains 69,354 proteins, which are classified into 85 families, based mainly on structural and functional criteria. Although OMPdb follows the annotation scheme of Pfam, many of the families included in the database were not previously described or annotated in other publicly available databases. There are also cross-references to other databases, references to the literature and annotation for sequence features, like transmembrane segments and signal peptides. Furthermore, via the web interface, the user can not only browse the available data, but submit advanced text searches and run BLAST queries against the database protein sequences or domain searches against the collection of profile Hidden Markov Models that represent each family's domain organization as well. The database is freely accessible for academic users at bioinformatics.biol.uoa.gr/OMPdb and we expect it to be useful for genome-wide analyses, comparative genomics as well as for providing training and test sets for predictive algorithms regarding transmembrane β-barrels.
Velentzas PD, Velentzas AD, Mpakou VE, Papassideri IS, Stravopodis DJ, Margaritis LH. (2011). Proteasome inhibition induces developmentally deregulated programs of apoptotic and autophagic cell death during Drosophila melanogaster oogenesis. . Cell Biol Int. 35(1):15-27.
Abstract: Ubiquitin/proteasome-mediated degradation of eukaryotic proteins is critically implicated in a number of signalling pathways and cellular processes. To specifically impair proteasome activities, in vitro developing Drosophila melanogaster egg chambers were exposed to the MG132 or epoxomicin proteasome inhibitors, while a GAL4/UAS binary genetic system was employed to generate double transgenic flies overexpressing β2 and β6 conditional mutant proteasome subunits in a cell type-specific manner. MG132 and epoxomicin administration resulted in severe deregulation of in vitro developing egg chambers, which was tightly associated with precocious induction of nurse cell-specific apoptotic and autophagic death programmes, featured by actin cytoskeleton disorganization, nuclear chromatin condensation, DRICE caspase activation and autophagosome accumulation. In vivo targeted overexpression of β2 and β6 conditional mutants, specifically in the nurse cell compartment, led to a notable up-regulation of sporadic apoptosis potency during early and mid-oogenesis 'checkpoints', thus reasonably justifying the observed reduction in eclosion efficiency. Furthermore, in response to the intracellular abundance of β2 and β6 conditional mutant forms, specifically in numerous tissues of third instar larval stage, the developmental course was arrested, and lethal phenotypes were obtained at this particular embryonic period, with the double transgenic heterozygote embryos being unable to further proceed to complete maturation to adult flies. Our data demonstrate that physiological proteasome function is required to ensure normal oogenesis and embryogenesis in D. melanogaster, since targeted and cell type-dependent proteasome inactivation initiates developmentally deregulated apoptotic and autophagic mechanisms.
Wilson J.R.U., Gairifo C., Gibson M.R., Arianoutsou M., Bakar B.B., Baret S., Celesti-Grapow L., Ditomaso J.M., Dufour-Dror J.-M., Kueffer C., Kull C.A., Hoffmann J.H., Impson F.A.C., Loope L.L., Marchante E., Marchante H., Moore J.L., Murphy D.J., Tassin J., Witt A., Zenni R.D. And Richardson D.M. (2011). Risk assessment, eradication, and biological control: global efforts to limit Australian acacia invasions.. Diversity and Distributions, 17, 1030–1046.
Abstract: Aim: Many Australian Acacia species have been planted around the world, some are highly valued, some are invasive, and some are both highly valued and invasive. We review global efforts to minimize the risk and limit the impact of invasions in this widely used plant group. Location: Global. Methods: Using information from literature sources, knowledge and experience of the authors, and the responses from a questionnaire sent to experts around the world, we reviewed: (1) a generalized life cycle of Australian acacias and how to control each life stage, (2) different management approaches and (3) what is required to help limit or prevent invasions. Results: Relatively few Australian acacias have been introduced in large numbers, but all species with a long and extensive history of planting have become invasive somewhere. Australian acacias, as a group, have a high risk of becoming invasive and causing significant impacts as determined by existing assessment schemes. Moreover, in most situations, long-lived seed banks mean it is very difficult to control established infestations. Control has focused almost exclusively on widespread invaders, and eradication has rarely been attempted. Classical biological control is being used in South Africa with increasing success. Main conclusions: A greater emphasis on pro-active rather than reactive management is required given the difficulties managing established invasions of Australian acacias. Adverse effects of proposed new introductions can be minimized by conducting detailed risk assessments in advance, planning for on-going monitoring and management, and ensuring resources are in place for long-term mitigation. Benign alternatives (e.g. sterile hybrids) could be developed to replace existing utilized taxa. Eradication should be set as a management goal more often to reduce the invasion debt. Introducing classical biological control agents that have a successful track-record in South Africa to other regions and identifying new agents (notably vegetative feeders) can help mitigate existing widespread invasions. Trans-boundary sharing of information will assist efforts to limit future invasions, in particular, management strategies need to be better evaluated, monitored, published and publicised so that global best-practice procedures can be developed.