Maria Klapa

Dr. Maria Klapa

Institute of Chemical Engineering Sciences (ICE-HT), Foundation for Research & Technology Hellas (FORTH), Patras, Greece
orcid

Research Focus & Metrics

Academic Career Length

20Years (2007-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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18 May 2022 in GigaScience
Verified
Journal Article
Open access
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Bjoern Marcus von ReumontBjoern Marcus von Reumont
Bjoern Marcus von Reumont
GAGregor Anderluh
Gregor Anderluh
Agostinho AntunesAgostinho Antunes
Agostinho Antunes
Naira AyvazyanNaira Ayvazyan
Naira Ayvazyan
DBDimitris Beis
Dimitris Beis
GZGiulia Zancolli
Giulia Zancolli
Venoms have evolved >100 times in all major animal groups, and their components, known as toxins, have been fine-tuned over millions of years into highly effective biochemical weapons. There are many outstanding questions on the evolution of toxin arsenals, such as how venom genes originate, how venom contributes to the fitness of venomous species, and which modifications at the genomic, transcriptomic, and protein level drive their evolution. These questions have received particularly little attention outside of snakes, cone snails, spiders, and scorpions. Venom compounds have further become a source of inspiration for translational research using their diverse bioactivities for various applications. We highlight here recent advances and new strategies in modern venomics and discuss how recent technological innovations and multi-omic methods dramatically improve research on venomous animals. The study of genomes and their modifications through CRISPR and knockdown technologies will increase our understanding of how toxins evolve and which functions they have in the different ontogenetic stages during the development of venomous animals. Mass spectrometry imaging combined with spatial transcriptomics, in situ hybridization techniques, and modern computer tomography gives us further insights into the spatial distribution of toxins in the venom system and the function of the venom apparatus. All these evolutionary and biological insights contribute to more efficiently identify venom compounds, which can then be synthesized or produced in adapted expression systems to test their bioactivity. Finally, we critically discuss recent agrochemical, pharmaceutical, therapeutic, and diagnostic (so-called translational) aspects of venoms from which humans benefit.

3 June 2016 in Plant Physiology
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Journal Article
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GTGeorgia Tooulakou
Georgia Tooulakou
AGAndreas Giannopoulos
Andreas Giannopoulos
DNDimosthenis Nikolopoulos
Dimosthenis Nikolopoulos
PBPanagiota Bresta
Panagiota Bresta
EDElissavet Dotsika
Elissavet Dotsika
GKGeorge Karabourniotis
George Karabourniotis
Calcium oxalate crystals are widespread among animals and plants. In land plants, crystals often reach high amounts - up to 80% of dry biomass. They are formed within specific cells, and their accumulation constitutes a normal activity rather than a pathological symptom, as occurs in animals. Despite their ubiquity, our knowledge on the formation and the possible role(s) of these crystals remains limited. We show that the mesophyll crystals of Amaranthus hybridus (pigweed) exhibit diurnal volume changes with a gradual decrease during daytime and a total recovery during the night. Moreover, stable carbon isotope composition indicated that crystals are of non-atmospheric origin. Stomatal closure (under drought conditions or exogenous application of abscisic acid) was accompanied by crystal decomposition and by increased activity of oxalate oxidase that converts oxalate into CO2. Similar results were also observed under drought stress in Dianthus chinensis, Pelargonium peltatum and Portulacaria afra. Moreover, in pigweed, despite closed stomata, the leaf metabolic profiles combined with chlorophyll fluorescence measurements indicated active photosynthetic metabolism. In combination, calcium oxalate crystals in leaves can act as a biochemical reservoir that collects non-atmospheric carbon, mainly during the night. During the day, crystal degradation provides subsidiary carbon for photosynthetic assimilation, especially under drought conditions. This new photosynthetic path, with the suggested name "alarm photosynthesis", seems to provide a number of adaptive advantages such as water economy, limitation of carbon losses to the atmosphere and a lower risk of photoinhibition, roles that justify its vast presence in plants.

14 April 2018
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Book Chapter
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MPMatthaios-Emmanouil P. Papadimitropoulos
Matthaios-Emmanouil P. Papadimitropoulos
CVCatherine G. Vasilopoulou
Catherine G. Vasilopoulou
CMChristoniki Maga-Nteve
Christoniki Maga-Nteve
Maria KlapaMaria Klapa
Maria Klapa

3 February 2022 in Nature Communications
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Journal Article
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ELEirini Lionaki
Eirini Lionaki
IGIlias Gkikas
Ilias Gkikas
IDIoanna Daskalaki
Ioanna Daskalaki
MIMaria-Konstantina Ioannidi
Maria-Konstantina Ioannidi
Maria KlapaMaria Klapa
Maria Klapa
Nektarios TavernarakisNektarios Tavernarakis
Nektarios Tavernarakis
Sustained mitochondrial fitness relies on coordinated biogenesis and clearance. Both processes are regulated by constant targeting of proteins into the organelle. Thus, mitochondrial protein import sets the pace for mitochondrial abundance and function. However, our understanding of mitochondrial protein translocation as a regulator of longevity remains enigmatic. Here, we targeted the main protein import translocases and assessed their contribution to mitochondrial abundance and organismal physiology. We find that reduction in cellular mitochondrial load through mitochondrial protein import system suppression, referred to as MitoMISS, elicits a distinct longevity paradigm. We show that MitoMISS triggers the mitochondrial unfolded protein response, orchestrating an adaptive reprogramming of metabolism. Glycolysis and de novo serine biosynthesis are causatively linked to longevity, whilst mitochondrial chaperone induction is dispensable for lifespan extension. Our findings extent the pro-longevity role of UPRmt and provide insight, relevant to the metabolic alterations that promote or undermine survival and longevity.

24 May 2016 in Frontiers in Physiology
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Journal Article
Open access
CVCatherine G. Vasilopoulou
Catherine G. Vasilopoulou
MMMarigoula Margarity
Marigoula Margarity
Maria KlapaMaria Klapa
Maria Klapa
Metabolism being a fundamental part of molecular physiology, elucidating the structure and regulation of metabolic pathways is crucial for obtaining a comprehensive perspective of cellular function and understanding the underlying mechanisms of its dysfunction(s). Therefore, quantifying an accurate metabolic network activity map under various physiological conditions is among the major objectives of systems biology in the context of many biological applications. Especially for CNS, metabolic network activity analysis can substantially enhance our knowledge about the complex structure of the mammalian brain and the mechanisms of neurological disorders, leading to the design of effective therapeutic treatments. Metabolomics has emerged as the high-throughput quantitative analysis of the concentration profile of small molecular weight metabolites, which act as reactants and products in metabolic reactions and as regulatory molecules of proteins participating in many biological processes. Thus, the metabolic profile provides a metabolic activity fingerprint, through the simultaneous analysis of tens to hundreds of molecules of pathophysiological and pharmacological interest. The application of metabolomics is at its standardization phase in general, and the challenges for paving a standardized procedure are even more pronounced in brain studies. In this review, we support the value of metabolomics in brain research. Moreover, we demonstrate the challenges of designing and setting up a reliable brain metabolomic study, which, among other parameters, has to take into consideration the sex differentiation and the complexity of brain physiology manifested in its regional variation. We finally propose ways to overcome these challenges and design a study that produces reproducible and consistent results.

29 December 2010 in BMC Systems Biology
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Journal Article
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HKHarin Kanani
Harin Kanani
BDBhaskar Dutta
Bhaskar Dutta
Maria KlapaMaria Klapa
Maria Klapa
Background: In this study, we investigated the individual and combinatorial effect of elevated CO2 conditions and salinity stress on the dynamics of both the transcriptional and metabolic physiology of Arabidopsis thaliana liquid hydroponic cultures over the first 30 hours of continuous treatment. Both perturbations are of particular interest in plant and agro-biotechnological applications. Moreover, within the timeframe of this experiment, they are expected to affect plant growth to opposite directions. Thus, a major objective was to investigate whether this expected "divergence" was valid for the individual perturbations and to study how it is manifested under the combined stress at two molecular levels of cellular function, using high-throughput analyses. Results: We observed that a) high salinity has stronger effect than elevated CO2 at both the transcriptional and metabolic levels, b) the transcriptional responses to the salinity and combined stresses exhibit strong similarity, implying a robust transcriptional machinery acting to the salinity stress independent of the co-occurrence of elevated CO2, c) the combinatorial effect of the two perturbations on the metabolic physiology is milder than of the salinity stress alone. Metabolomic analysis suggested that the beneficial role of elevated CO2 on salt-stressed plants within the timeframe of this study should be attributed to the provided additional resources; these allow the plants to respond to high salinity without having to forfeit other major metabolic functions, and d) 9 h-12 h and 24 h of treatment coincide with significant changes in the metabolic physiology under any of the investigated stresses. Significant differences between the acute and longer term responses were observed at both molecular levels. Conclusions: This study contributes large-scale dynamic omic data from two levels of cellular function for a plant system under various stresses. It provides an additional example of the power of integrated omic analyses for the comprehensive study of the molecular physiology of complex biological systems. Moreover, taking into consideration the particular interest of the two investigated perturbations in plant biotechnology, enhanced understanding of the molecular physiology of the plants under these conditions could lead to the design of novel metabolic engineering strategies to increase the resistance of commercial crops to salinity stress.