A cyanobacterium producing β-glucosidase was isolated from Lake Pamvotis located in Ioannina in G... more A cyanobacterium producing β-glucosidase was isolated from Lake Pamvotis located in Ioannina in Greece. This microorganism, named Pamv7, was identified as Pseudanabaena sp. using phylogenetic characterization. The high-throughput BiologMicroPlate™ method, used for the rapid assessment of heterotrophic potential, indicates that Pseudanabaena sp. metabolizes a wide range of organic substrates such as amino acids, carbohydrates, and carboxylic acids. When the strain grows in a culture medium containing cellobiose as a carbon source, it produces a significant amount of intracellular β-glucosidase. The effect of cellobiose concentration, nitrogen source, and nitrogen concentration of the growth medium, as well as the temperature of the culture, on biomass and β-glucosidase by Pseudanabaena sp., was studied. Biomass and β-glucosidase production by the strain in a lab-scale bioreactor at optimal conditions (10 g/L cellobiose, 1.5 g/L yeast, and 23 ± 1 °C) reached 2.8 g dry weight/L and 44 ...
Prothymosin a and parathymosin are two small, acidic, well conserved proteins which show a ~40% s... more Prothymosin a and parathymosin are two small, acidic, well conserved proteins which show a ~40% structural identity. To investigate the putative role of prothyhmosin a in cellular proliferation we studied the protein profile throughout the cell cycle. After cell synchronization we established that the prothymosin a mRNA induced in G1-S transition and peaks at S/S2-M phase of the cycle, a pattern that coincide with that of cyclins a and b. To address the question of regulation of prothymosin a gene we found that the promoter activity of the gene is strongly up-regulated in the presence of E2F transcription factor. Finally we found an apparent correlation between c-myc oncogene and prothymosin a expression during placenta development, heat shock and vital infection. Our data on parathymosin indicate that the gene expression remains constant during development and is highly associated with the type of cells studied.Η προθυμοσίνη α και η παραθυμοσίνη είναι δύο μικρές, όξινες και πολύ κα...
Large dorsal dark spots were observed in a number of alpine newts Ichthyosaura alpestris inhabiti... more Large dorsal dark spots were observed in a number of alpine newts Ichthyosaura alpestris inhabiting Lake Gistova, the highest altitude alpine lake in the Balkans ever studied. The trait is mainly exhibited by female paedomorphs. Histopathological examination excluded any pathological cause of pigmented skin and revealed that even in paedomorphic skin sections, the altered pigmentation pattern was located only in regions with metamorphic characteristics. Phylogenetic analysis of the previously unstudied Gistova’s newt population based on mtDNA sequences revealed that it belongs to the D2 subclade, comprising only two other newt populations of the wider geographic region that interestingly, also exhibit the trait. The putative genetic or environmental basis for dark spot appearance in these populations is discussed.
Pemphigus is an autoimmune bullous disorder caused by autoantibodies against desmosomal cadherins... more Pemphigus is an autoimmune bullous disorder caused by autoantibodies against desmosomal cadherins. The most common clinical forms are pemphigus vulgaris (PV) and pemphigus foliaceus (PF). Among the numerous proteins that are considered responsible for the cohesion of keratinocytes in epidermis, desmocollin-3 (Dsc-3) has been initially reported to participate in epidermal blistering in mice. There have been reports in which autoantibodies against Dsc-3 have been detected. In PV, a limited number of studies found no presence of IgG or IgA autoantibodies against Dsc-3. In this study we examined sera from Greek patients with PV and PF for the presence of IgG autoantibodies against Dsc-3. Immunoblotting for the detection of autoantibodies against Dsc-3 was performed in sera from all cases. Dsc-3 autoantibodies were not detected in either group (PV and PF). Our results confirm the hypothesis that the pathogenic role of Dsc-3 in epidermal blistering in PV and PF remains controversial.
We explore how the phyllosphere microbial community responds to a very seasonal environment such ... more We explore how the phyllosphere microbial community responds to a very seasonal environment such as the Mediterranean. For this, we studied the epiphytic bacterial community of a Mediterranean ecosystem in summer and winter, expecting to detect seasonal differences at their maximum. With high-throughput sequencing (HTS), we detected the operational taxonomic units (OTUs) present in the phyllosphere and also in the surrounding air. The epiphytic community is approximately five orders of magnitude denser than the airborne one and is made almost exclusively by habitat specialists. The two communities differ considerably but Proteobacteria and Actinobacteria are dominant in both. Of the five most abundant phyllosphere OTUs, two were closely related to Sphingomonas strains, one to Methylobacterium and the other two to Rhizobiales and Burkholderiales. We found the epiphytic community to become much richer, more distinct, even and diverse, denser and more connected in summer. In contrast, ...
Η προθυμοσίνη α και η παραθυμοσίνη είναι δύο μικρές, όξινες και πολύ καλά διατηρημένες πρωτεΐνες ... more Η προθυμοσίνη α και η παραθυμοσίνη είναι δύο μικρές, όξινες και πολύ καλά διατηρημένες πρωτεΐνες που παρουσιάζουν ομολογία 40%. Σε μια προσπάθεια να εξετάσουμε τον ρόλο της προθυμοσίνης α στον κυτταρικό πολλαπλασιασμό, μελετήσαμε την έκφραση της πρωτεΐνης στην πορεία του κυτταρικού κύκλου και διαπιστώσαμε επαγωγή του mRNA της, στην μετάβαση G1-S και το μέγιστο στην S/G2-M φάση του κύκλου. Η έκφραση αυτή παραλληλίζεται με την έκφραση των κυκλινών α και β που επίσης μελετήθηκαν. Διαπιστώθηκε επίσης ότι η μεταγραφή του γονιδίου της προθυμοσίνης α επάγεται από τον μεταγραφικό παράγοντα E2F. Τέλος διαπιστώθηκε παράλληλη έκφραση της προθυμοσίνης α και του αλογονιδίου c-myc κατά την διάρκεια ανάπτυξης του ανθρώπινου πλακούντα, σε ιικές μολύνσεις και μετά από την επίδραση θερμικού σοκ. Όσον αφορά την παραθυμοσίνη διαπιστώθηκε ότι η έκφραση του γονιδίου της δεν σχετίζεται με την ανάπτυξη, επηρεάζεται όμως καθοριστικά από το είδος των κυτταρικών πληθυσμών που μελετούνται.
The eutrophic character of a growing number of freshwaters around the world is a global health co... more The eutrophic character of a growing number of freshwaters around the world is a global health concern as in these high nutrient ecosystems toxic cyanobacteria often bloom. The well-studied cyanobacterial toxins are microcystins (MCs), a family of more than 90 closely related hepatotoxic heptapeptides. Since MCs are products of the first trophic level, they tend to accumulate in the food chain. Moreover, there is evidence suggesting that irrigation with contaminated water results in severely contaminated crops. As expected, scientific efforts have focused on the elucidation of mechanisms for cyanobacterial bloom formation and toxicity in these eutrophic freshwaters. However, recent studies indicated that oligotrophic freshwaters are also prone to toxic cyanobacterial blooms. In this context, we compared the toxic potential of two low nutrient lakes in NW Greece to a eutrophic lake of the same region. Interestingly, in seston samples, MC concentrations were found to be higher in these lakes. Cyanobacterial communities were compared based on molecular data. Our findings suggest that the MC producers are mainly cosmopolitan non-diazotrophic cyanobacteria. In conclusion, based on the results, monitoring programs should be established for oligotrophic lakes to prevent of health hazards from use of such “innocent” ecosystems.
MicroRNAs are small RNA molecules that negatively regulate the expression of the majority of prot... more MicroRNAs are small RNA molecules that negatively regulate the expression of the majority of proteins, mainly at the post-transcriptional level. Being stable in the circulation and resistant to storage handling, they are potentially promising biomarkers. We measured RNA levels of three microRNAs with tumorigenic or angiogenic potential (miR-155, miR-195, and miR-21) in blood samples taken from patients with early breast cancer, both preoperatively and postoperatively. We found that persistently elevated postoperative levels of miR-195 were detected only in patients who developed early tumor relapse and that miR-155 levels tended to increase three days postoperatively (p=0.05) and fell below baseline one month post-surgery (p<0.05). We had no major findings for miR-21. The results of this pilot study indicate a possible involvement of miR-155 in surgery-induced angiogenesis and potential prognostic significance of high postoperative levels of circulating miR-195 in patients with b...
Peroxisome proliferator-activated receptor-gamma (PPAR), one of three ligand-activated transcript... more Peroxisome proliferator-activated receptor-gamma (PPAR), one of three ligand-activated transcription factors named PPAR, has been identified as a molecular target for cancer chemopreventive agents. PPAR was initially understood as a regulator of adipocyte differentiation and glucose homeostasis while later on, it became evident that it is also involved in cell differentiation, apoptosis, and angiogenesis, biological processes which are deregulated in cancer. It is now established that PPAR ligands can induce cell differentiation and yield early antineoplastic effects in several tumor types. Moreover, several bioactive natural products with cancer protecting potential are shown to operate through activation of PPAR. Overall, PPAR appears to be a prevalent target ally to cancer chemopreventive agents and therefore pursuing research in this area is of great relevance.
A cyanobacterium producing β-glucosidase was isolated from Lake Pamvotis located in Ioannina in G... more A cyanobacterium producing β-glucosidase was isolated from Lake Pamvotis located in Ioannina in Greece. This microorganism, named Pamv7, was identified as Pseudanabaena sp. using phylogenetic characterization. The high-throughput BiologMicroPlate™ method, used for the rapid assessment of heterotrophic potential, indicates that Pseudanabaena sp. metabolizes a wide range of organic substrates such as amino acids, carbohydrates, and carboxylic acids. When the strain grows in a culture medium containing cellobiose as a carbon source, it produces a significant amount of intracellular β-glucosidase. The effect of cellobiose concentration, nitrogen source, and nitrogen concentration of the growth medium, as well as the temperature of the culture, on biomass and β-glucosidase by Pseudanabaena sp., was studied. Biomass and β-glucosidase production by the strain in a lab-scale bioreactor at optimal conditions (10 g/L cellobiose, 1.5 g/L yeast, and 23 ± 1 °C) reached 2.8 g dry weight/L and 44 ...
Prothymosin a and parathymosin are two small, acidic, well conserved proteins which show a ~40% s... more Prothymosin a and parathymosin are two small, acidic, well conserved proteins which show a ~40% structural identity. To investigate the putative role of prothyhmosin a in cellular proliferation we studied the protein profile throughout the cell cycle. After cell synchronization we established that the prothymosin a mRNA induced in G1-S transition and peaks at S/S2-M phase of the cycle, a pattern that coincide with that of cyclins a and b. To address the question of regulation of prothymosin a gene we found that the promoter activity of the gene is strongly up-regulated in the presence of E2F transcription factor. Finally we found an apparent correlation between c-myc oncogene and prothymosin a expression during placenta development, heat shock and vital infection. Our data on parathymosin indicate that the gene expression remains constant during development and is highly associated with the type of cells studied.Η προθυμοσίνη α και η παραθυμοσίνη είναι δύο μικρές, όξινες και πολύ κα...
Large dorsal dark spots were observed in a number of alpine newts Ichthyosaura alpestris inhabiti... more Large dorsal dark spots were observed in a number of alpine newts Ichthyosaura alpestris inhabiting Lake Gistova, the highest altitude alpine lake in the Balkans ever studied. The trait is mainly exhibited by female paedomorphs. Histopathological examination excluded any pathological cause of pigmented skin and revealed that even in paedomorphic skin sections, the altered pigmentation pattern was located only in regions with metamorphic characteristics. Phylogenetic analysis of the previously unstudied Gistova’s newt population based on mtDNA sequences revealed that it belongs to the D2 subclade, comprising only two other newt populations of the wider geographic region that interestingly, also exhibit the trait. The putative genetic or environmental basis for dark spot appearance in these populations is discussed.
Pemphigus is an autoimmune bullous disorder caused by autoantibodies against desmosomal cadherins... more Pemphigus is an autoimmune bullous disorder caused by autoantibodies against desmosomal cadherins. The most common clinical forms are pemphigus vulgaris (PV) and pemphigus foliaceus (PF). Among the numerous proteins that are considered responsible for the cohesion of keratinocytes in epidermis, desmocollin-3 (Dsc-3) has been initially reported to participate in epidermal blistering in mice. There have been reports in which autoantibodies against Dsc-3 have been detected. In PV, a limited number of studies found no presence of IgG or IgA autoantibodies against Dsc-3. In this study we examined sera from Greek patients with PV and PF for the presence of IgG autoantibodies against Dsc-3. Immunoblotting for the detection of autoantibodies against Dsc-3 was performed in sera from all cases. Dsc-3 autoantibodies were not detected in either group (PV and PF). Our results confirm the hypothesis that the pathogenic role of Dsc-3 in epidermal blistering in PV and PF remains controversial.
We explore how the phyllosphere microbial community responds to a very seasonal environment such ... more We explore how the phyllosphere microbial community responds to a very seasonal environment such as the Mediterranean. For this, we studied the epiphytic bacterial community of a Mediterranean ecosystem in summer and winter, expecting to detect seasonal differences at their maximum. With high-throughput sequencing (HTS), we detected the operational taxonomic units (OTUs) present in the phyllosphere and also in the surrounding air. The epiphytic community is approximately five orders of magnitude denser than the airborne one and is made almost exclusively by habitat specialists. The two communities differ considerably but Proteobacteria and Actinobacteria are dominant in both. Of the five most abundant phyllosphere OTUs, two were closely related to Sphingomonas strains, one to Methylobacterium and the other two to Rhizobiales and Burkholderiales. We found the epiphytic community to become much richer, more distinct, even and diverse, denser and more connected in summer. In contrast, ...
Η προθυμοσίνη α και η παραθυμοσίνη είναι δύο μικρές, όξινες και πολύ καλά διατηρημένες πρωτεΐνες ... more Η προθυμοσίνη α και η παραθυμοσίνη είναι δύο μικρές, όξινες και πολύ καλά διατηρημένες πρωτεΐνες που παρουσιάζουν ομολογία 40%. Σε μια προσπάθεια να εξετάσουμε τον ρόλο της προθυμοσίνης α στον κυτταρικό πολλαπλασιασμό, μελετήσαμε την έκφραση της πρωτεΐνης στην πορεία του κυτταρικού κύκλου και διαπιστώσαμε επαγωγή του mRNA της, στην μετάβαση G1-S και το μέγιστο στην S/G2-M φάση του κύκλου. Η έκφραση αυτή παραλληλίζεται με την έκφραση των κυκλινών α και β που επίσης μελετήθηκαν. Διαπιστώθηκε επίσης ότι η μεταγραφή του γονιδίου της προθυμοσίνης α επάγεται από τον μεταγραφικό παράγοντα E2F. Τέλος διαπιστώθηκε παράλληλη έκφραση της προθυμοσίνης α και του αλογονιδίου c-myc κατά την διάρκεια ανάπτυξης του ανθρώπινου πλακούντα, σε ιικές μολύνσεις και μετά από την επίδραση θερμικού σοκ. Όσον αφορά την παραθυμοσίνη διαπιστώθηκε ότι η έκφραση του γονιδίου της δεν σχετίζεται με την ανάπτυξη, επηρεάζεται όμως καθοριστικά από το είδος των κυτταρικών πληθυσμών που μελετούνται.
The eutrophic character of a growing number of freshwaters around the world is a global health co... more The eutrophic character of a growing number of freshwaters around the world is a global health concern as in these high nutrient ecosystems toxic cyanobacteria often bloom. The well-studied cyanobacterial toxins are microcystins (MCs), a family of more than 90 closely related hepatotoxic heptapeptides. Since MCs are products of the first trophic level, they tend to accumulate in the food chain. Moreover, there is evidence suggesting that irrigation with contaminated water results in severely contaminated crops. As expected, scientific efforts have focused on the elucidation of mechanisms for cyanobacterial bloom formation and toxicity in these eutrophic freshwaters. However, recent studies indicated that oligotrophic freshwaters are also prone to toxic cyanobacterial blooms. In this context, we compared the toxic potential of two low nutrient lakes in NW Greece to a eutrophic lake of the same region. Interestingly, in seston samples, MC concentrations were found to be higher in these lakes. Cyanobacterial communities were compared based on molecular data. Our findings suggest that the MC producers are mainly cosmopolitan non-diazotrophic cyanobacteria. In conclusion, based on the results, monitoring programs should be established for oligotrophic lakes to prevent of health hazards from use of such “innocent” ecosystems.
MicroRNAs are small RNA molecules that negatively regulate the expression of the majority of prot... more MicroRNAs are small RNA molecules that negatively regulate the expression of the majority of proteins, mainly at the post-transcriptional level. Being stable in the circulation and resistant to storage handling, they are potentially promising biomarkers. We measured RNA levels of three microRNAs with tumorigenic or angiogenic potential (miR-155, miR-195, and miR-21) in blood samples taken from patients with early breast cancer, both preoperatively and postoperatively. We found that persistently elevated postoperative levels of miR-195 were detected only in patients who developed early tumor relapse and that miR-155 levels tended to increase three days postoperatively (p=0.05) and fell below baseline one month post-surgery (p<0.05). We had no major findings for miR-21. The results of this pilot study indicate a possible involvement of miR-155 in surgery-induced angiogenesis and potential prognostic significance of high postoperative levels of circulating miR-195 in patients with b...
Peroxisome proliferator-activated receptor-gamma (PPAR), one of three ligand-activated transcript... more Peroxisome proliferator-activated receptor-gamma (PPAR), one of three ligand-activated transcription factors named PPAR, has been identified as a molecular target for cancer chemopreventive agents. PPAR was initially understood as a regulator of adipocyte differentiation and glucose homeostasis while later on, it became evident that it is also involved in cell differentiation, apoptosis, and angiogenesis, biological processes which are deregulated in cancer. It is now established that PPAR ligands can induce cell differentiation and yield early antineoplastic effects in several tumor types. Moreover, several bioactive natural products with cancer protecting potential are shown to operate through activation of PPAR. Overall, PPAR appears to be a prevalent target ally to cancer chemopreventive agents and therefore pursuing research in this area is of great relevance.
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