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1051 - 1060 / 2000
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1051.
Reverse transcriptase droplet digital PCR shows high resilience to PCR inhibitors from plant, soil and water samples
Nejc Rački, Tanja Dreo, Ion Gutiérrez-Aguirre, Andrej Blejec, Maja Ravnikar, 2014, original scientific article

Abstract: Background Detection and quantification of plant pathogens in the presence of inhibitory substances can be a challenge especially with plant and environmental samples. Real-time quantitative PCR has enabled high-throughput detection and quantification of pathogens; however, its quantitative use is linked to standardized reference materials, and its sensitivity to inhibitors can lead to lower quantification accuracy. Droplet digital PCR has been proposed as a method to overcome these drawbacks. Its absolute quantification does not rely on standards and its tolerance to inhibitors has been demonstrated mostly in clinical samples. Such features would be of great use in agricultural and environmental fields, therefore our study compared the performance of droplet digital PCR method when challenged with inhibitors common to plant and environmental samples and compared it with quantitative PCR. Results Transfer of an existing Pepper mild mottle virus assay from reverse transcription real-time quantitative PCR to reverse transcription droplet digital PCR was straight forward. When challenged with complex matrices (seeds, plants, soil, wastewater) and selected purified inhibitors droplet digital PCR showed higher resilience to inhibition for the quantification of an RNA virus (Pepper mild mottle virus), compared to reverse transcription real-time quantitative PCR. Conclusions This study confirms the improved detection and quantification of the PMMoV RT-ddPCR in the presence of inhibitors that are commonly found in samples of seeds, plant material, soil, and wastewater. Together with absolute quantification, independent of standard reference materials, this makes droplet digital PCR a valuable tool for detection and quantification of pathogens in inhibition prone samples.
Keywords: PCR amplification, inhibition, qPCR, droplet digital PCR, environmental samples
Published in DiRROS: 02.08.2024; Views: 348; Downloads: 191
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1052.
TRIM28 and [beta]-actin identified via nanobody-based reverse proteomics approach as possible human glioblastoma biomarkers
Ivana Jovchevska, Neja Šamec, Nina Kočevar Britovšek, Daniela Cesselli, Neža Podergajs, Clara Limbaeck Stanic, Michael P. Myers, Serge Muyldermans, Gholamreza Hassanzadeh Ghassabeh, Helena Motaln, Maria Elisabetta Ruaro, Evgenia Bourkoula, Tamara Lah Turnšek, Radovan Komel, 2014, original scientific article

Abstract: Malignant gliomas are among the rarest brain tumours, and they have the worst prognosis. Grade IV astrocytoma, known as glioblastoma multiforme (GBM), is a highly lethal disease where the standard therapies of surgery, followed by radiation and chemotherapy, cannot significantly prolong the life expectancy of the patients. Tumour recurrence shows more aggressive form compared to the primary tumour, and results in patient survival from 12 to 15 months only. Although still controversial, the cancer stem cell hypothesis postulates that cancer stem cells are responsible for early relapse of the disease after surgical intervention due to their high resistance to therapy. Alternative strategies for GBM therapy are thus urgently needed. Nanobodies are single-domain antigen-binding fragments of heavy-chain antibodies, and together with classical antibodies, they are part of the camelid immune system. Nanobodies are small and stable, and they share a high degree of sequence identity to the human heavy chain variable domain, and these characteristics offer them advantages over classical antibodies or antibody fragments. We first immunised an alpaca with a human GBM stem-like cell line prepared from primary GBM cultures. Next, a nanobody library was constructed in a phage-display vector. Using nanobody phage-display technology, we selected specific GBM stem-like cell binders through a number of affinity selections, using whole cell protein extracts and membrane protein-enriched extracts from eight different GBM patients, and membrane protein-enriched extracts from two established GBM stem-like cell lines (NCH644 and NCH421K cells). After the enrichment, periplasmic extract ELISA was used to screen for specific clones. These nanobody clones were recloned into the pHEN6 vector, expressed in Escherichia coli WK6, and purified using immobilised metal affinity chromatography and size-exclusion chromatography. Specific nanobody:antigen pairs were obtained and mass spectrometry analysis revealed two proteins, TRIM28 and β-actin, that were up-regulated in the GBM stem-like cells compared to the controls.
Keywords: malignant gliomas, cancer stem cells, nanobodies
Published in DiRROS: 02.08.2024; Views: 442; Downloads: 293
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1053.
Seasonal variation in marine-snow-associated and ambient-water prokaryotic communities in the northern Adriatic Sea
Jana Vojvoda, Dominique Lamy, Eva Sintes, Juan A.L. Garcia, Valentina Turk, Gerhard J. Herndl, 2014, original scientific article

Abstract: The structure and activity of prokaryotic communities were determined in marine snow and in the ambient water of the northern Adriatic Sea in different seasons (autumn, spring and summer). The seasonal variation in the composition of marine-snow-associated and ambient-water bacterial communities was assessed by T-RFLP (Terminal Restriction Fragment Length Polymorphism) on the 16S rRNA gene (16S rDNA) and 16S rRNA transcript (16S rRNA) level. On the 16S rDNA level, the bacterial community composition of the marine snow and ambient water was similar in summer and autumn, but not in spring. In contrast, on the 16S rRNA level, indicative of the active bacterial community, the marine-snow-associated bacterial community was different from that of the ambient-water, and different from the bacterial community on the 16S rDNA level, except in autumn. To phylogenetically characterize the bacterial and archaeal community composition associated with marine snow and the ambient water, clone libraries of 16S rDNA and 16S rRNA were constructed from 2 contrasting seasons. Phylogenetic profiling revealed a higher similarity among bacterial communities in summer compared to late autumn. Certain bacterial and archaeal groups were exclusively associated with summer or autumn marine snow, suggesting that marine-snow-associated prokaryotic communities are subjected to successional changes similar to ambient-water communities. Moreover, the presence of bacterial groups enriched in marine snow including Vibrionales and sulphate-reducing bacteria is consistent with niche partitioning and metabolic adaptations of the particle-associated microbiota.
Keywords: marine snow, free-living-bacteria, Northern Adriatic sea
Published in DiRROS: 02.08.2024; Views: 399; Downloads: 204
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1054.
Expression analysis of all protease genes reveals cathepsin K to be overexpressed in glioblastoma
Urška Verbovšek, Helena Motaln, Ana Rotter, Nadia A. Atai, Kristina Gruden, Cornelis J. F. van Noorden, Tamara Lah Turnšek, 2014, original scientific article

Abstract: Background Cancer genome and transcriptome analyses advanced our understanding of cancer biology. We performed transcriptome analysis of all known genes of peptidases also called proteases and their endogenous inhibitors in glioblastoma multiforme (GBM), which is one of the most aggressive and deadly types of brain cancers, where unbalanced proteolysis is associated with tumor progression. Methods Comparisons were performed between the transcriptomics of primary GBM tumors and unmatched non-malignant brain tissue, and between GBM cell lines (U87-MG and U373) and a control human astrocyte cell line (NHA). Publicly-available data sets and our own datasets were integrated and normalized using bioinformatics tools to reveal protease and protease inhibitor genes with deregulated expression in both malignant versus non-malignant tissues and cells. Results Of the 311 protease genes identified to be differentially expressed in both GBM tissues and cells, 5 genes were highly overexpressed, 2 genes coding for non-peptidase homologues transferrin receptor (TFRC) and G protein-coupled receptor 56 (GPR56), as well as 3 genes coding for the proteases endoplasmic reticulum aminopeptidase 2 (ERAP2), glutamine-fructose-6-phosphate transaminase 2 (GFPT2) and cathepsin K (CTSK), whereas one gene, that of the serine protease carboxypeptidase E (CPE) was strongly reduced in expression. Seventy five protease inhibitor genes were differentially expressed, of which 3 genes were highly overexpressed, the genes coding for stefin B (CSTB), peptidase inhibitor 3 (PI3 also named elafin) and CD74. Seven out of 8 genes (except CSTB) were validated using RT-qPCR in GBM cell lines. CTSK overexpression was validated using RT-qPCR in GBM tissues as well. Cathepsin K immunohistochemical staining and western blotting showed that only proteolytically inactive proforms of cathepsin K were overexpressed in GBM tissues and cells. Conclusions The presence of high levels of inactive proforms of cathepsin K in GBM tissues and cells indicate that in GBM the proteolytic/collagenolytic role is not its primary function but it plays rather a different yet unknown role.
Keywords: glioblastoma multiforme, genes
Published in DiRROS: 02.08.2024; Views: 445; Downloads: 243
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1055.
The subgenual organ complex in the cave cricket Troglophilus neglectus (Orthoptera: Rhaphidophoridae) : comparative innervation and sensory evolution
Johannes Strauß, Nataša Stritih Peljhan, Reinhard Lakes-Harlan, 2014, original scientific article

Abstract: Comparative studies of the organization of nervous systems and sensory organs can reveal their evolution and specific adaptations. In the forelegs of some Ensifera (including crickets and tettigoniids), tympanal hearing organs are located in close proximity to the mechanosensitive subgenual organ (SGO). In the present study, the SGO complex in the non-hearing cave cricket Troglophilus neglectus (Rhaphidophoridae) is investigated for the neuronal innervation pattern and for organs homologous to the hearing organs in related taxa. We analyse the innervation pattern of the sensory organs (SGO and intermediate organ (IO)) and its variability between individuals. In T. neglectus, the IO consists of two major groups of closely associated sensilla with different positions. While the distal-most sensilla superficially resemble tettigoniid auditory sensilla in location and orientation, the sensory innervation does not show these two groups to be distinct organs. Though variability in the number of sensory nerve branches occurs, usually either organ is supplied by a single nerve branch. Hence, no sensory elements clearly homologous to the auditory organ are evident. In contrast to other non-hearing Ensifera, the cave cricket sensory structures are relatively simple, consistent with a plesiomorphic organization resembling sensory innervation in grasshoppers and stick insects.
Keywords: neuroanatomy, chordotonal organ, mechanoreceptor, sensory innervation, neural phylogeny
Published in DiRROS: 02.08.2024; Views: 306; Downloads: 279
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1056.
Potato Virus Y infection hinders potato defence response and renders plants more vulnerable to Colorado potato beetle attack
Marko Petek, Ana Rotter, Polona Kogovšek, Špela Baebler, Axel Mithöfer, Kristina Gruden, 2014, original scientific article

Abstract: In the field, plants are challenged by more than one biotic stressor at the same time. In this study, the molecular interactions between potato (Solanum tuberosum L.), Colorado potato beetle (Leptinotarsa decemlineata Say; CPB) and Potato virus YNTN (PVYNTN) were investigated through analyses of gene expression in the potato leaves and the gut of the CPB larvae, and of the release of potato volatile compounds. CPB larval growth was enhanced when reared on secondary PVYNTN-infected plants, which was linked to decreased accumulation of transcripts associated with the antinutritional properties of potato. In PVYNTN-infected plants, ethylene signalling pathway induction and induction of auxin response transcription factors were attenuated, while no differences were observed in jasmonic acid (JA) signalling pathway. Similarly to rearing on virus-infected plants, CPB larvae gained more weight when reared on plants silenced in JA receptor gene (coi1). Although herbivore-induced defence mechanism is regulated predominantly by JA, response in coi1-silenced plants only partially corresponded to the one observed in PVYNTN-infected plants, confirming the role of other plant hormones in modulating this response. The release of β-barbatene and benzyl alcohol was different in healthy and PVYNTN-infected plants before CPB larvae infestation, implicating the importance of PVYNTN infection in plant communication with its environment. This was reflected in gene expression profiles of neighbouring plants showing different degree of defence response. This study thus contributes to our understanding of plant responses in agro-ecosystems.
Keywords: insect midgut transcriptional response, gene expression, plant defence, volatile organic compounds, potato
Published in DiRROS: 02.08.2024; Views: 411; Downloads: 209
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1057.
Involvement of potato (Solanum tuberosum L.) MKK6 in response to Potato virus Y
Ana Lazar, Anna Coll Rius, David Dobnik, Špela Baebler, Apolonija Bedina Zavec, Jana Žel, Kristina Gruden, 2014, original scientific article

Abstract: Mitogen-activated protein kinase (MAPK) cascades have crucial roles in the regulation of plant development and in plant responses to stress. Plant recognition of pathogen-associated molecular patterns or pathogen-derived effector proteins has been shown to trigger activation of several MAPKs. This then controls defence responses, including synthesis and/or signalling of defence hormones and activation of defence related genes. The MAPK cascade genes are highly complex and interconnected, and thus the precise signalling mechanisms in specific plant%pathogen interactions are still not known. Here we investigated the MAPK signalling network involved in immune responses of potato (Solanum tuberosum L.) to Potato virus Y, an important potato pathogen worldwide. Sequence analysis was performed to identify the complete MAPK kinase (MKK) family in potato, and to identify those regulated in the hypersensitive resistance response to Potato virus Y infection. Arabidopsis has 10 MKK family members, of which we identified five in potato and tomato (Solanum lycopersicum L.), and eight in Nicotiana benthamiana. Among these, StMKK6 is the most strongly regulated gene in response to Potato virus Y. The salicylic acid treatment revealed that StMKK6 is regulated by the hormone that is in agreement with the salicylic acid-regulated domains found in the StMKK6 promoter. The involvement of StMKK6 in potato defence response was confirmed by localisation studies, where StMKK6 accumulated strongly only in Potato-virus-Y-infected plants, and predominantly in the cell nucleus. Using a yeast two-hybrid method, we identified three StMKK6 targets downstream in the MAPK cascade: StMAPK4_2, StMAPK6 and StMAPK13. These data together provide further insight into the StMKK6 signalling module and its involvement in plant defence.
Keywords: plant diseases, potato, molecular biology
Published in DiRROS: 02.08.2024; Views: 332; Downloads: 262
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1058.
The process of pair formation mediated by substrate-borne vibrationsin a small insect
Jernej Polajnar, Anna Eriksson, Marco Valerio Rossi Stacconi, Andrea Lucchi, Gianfranco Anfora, Meta Virant-Doberlet, Valerio Mazzoni, 2014, original scientific article

Abstract: The ability to identify and locate conspecifics depends on reliable transfer of information between emitter and receiver. For a majority of plant-dwelling insects communicating with substrate-borne vibrations, localization of a potential partner may be a difficult task due to their small body size and complex transmission properties of plants. In the present study, we used the leafhopper Scaphoideus titanus as a model to investigate duetting and mate searching associated with pair formation. Studying these insects on a natural substrate, we showed that the spatio-temporal structure of a vibrational duet and the perceived intensity of partner's signals influence the mating behaviour. Identification, localization and courtship stages were each characterized by a specific duet structure. In particular, the duet structure differed in synchronization between male and female pulses, which enables identification of the partner, while the switch between behavioural stages was associated with the male-perceived intensity of vibrational signals. This suggests that males obtain the information about their distance from the female and optimize their strategy accordingly. More broadly, our results show that even in insects smaller than 1 cm, vibrational signals provide reliable information needed to find a mating partner.
Keywords: mating behaviour, identification, localization, courtship, vibrational communication
Published in DiRROS: 02.08.2024; Views: 375; Downloads: 213
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1059.
Macrofauna associated with a bank of Cladocora caespitosa (Anthozoa, Scleractinia) in the Gulf of Trieste (northern Adriatic)
Valentina Pitacco, Martina Orlando-Bonaca, Borut Mavrič, Lovrenc Lipej, 2014, original scientific article

Abstract: The Mediterranean stony coral Cladocora caespitosa (Linnaeus, 1767) is a native colonial, zooxanthellate, shallow water coral, particularly sensitive to global changes and anthropogenic activities. Due to its shape and size, it is able to host a diversifi ed faunal assemblage, which is still relatively unknown. A recently discovered bank of C. caespitosa, discovered close to Cape Ronek (Gulf of Trieste, Slovenia), was investigated in November 2010. Altogether 121 invertebrate taxa, belonging to 9 different phyla were found. Taxa composition in colonies differed markedly from the surrounding areas within the bank. Only 5 taxa (4 % of the total) were found both within and without C. caespitosa colonies. Our results confi rm the role of C. caespitosa as a habitat builder and indicate the importance of the studied bank for biodiversity
Published in DiRROS: 02.08.2024; Views: 327; Downloads: 317
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1060.
Mixtures of Chemical Pollutants at European Legislation Safety Concentrations: How Safe are They?
Raquel Negrão Carvalho, Augustine Aruqwe, Selim Ait-Aissa, Anne Bado-Nilles, Stefania Balzamo, Anders Baun, Shimshon Belkin, Ludek Blaha, Francois Brion, Daniela Conti, Vesna Flander-Putrle, Valentina Turk, 2014, original scientific article

Abstract: The risk posed by complex chemical mixtures in the environment to wildlife and humans is increasingly debated, but has been rarely tested under environmentally relevant scenarios. To address this issue, two mixtures of 14 or 19 substances of concern (pesticides, pharmaceuticals, heavy metals, polyaromatic hydrocarbons, a surfactant, and a plasticizer), each present at its safety limit concentration imposed by the European legislation, were prepared and tested for their toxic effects. The effects of the mixtures were assessed in 35 bioassays, based on 11 organisms representing different trophic levels. A consortium of 16 laboratories was involved in performing the bioassays. The mixtures elicited quantifiable toxic effects on some of the test systems employed, including i) changes in marine microbial composition, ii) microalgae toxicity, iii) immobilization in the crustacean Daphnia magna, iv) fish embryo toxicity, v) impaired frog embryo development, and vi) increased expression on oxidative stress-linked reporter genes. Estrogenic activity close to regulatory safety limit concentrations was uncovered by receptor-binding assays. The results highlight the need of precautionary actions on the assessment of chemical mixtures even in cases where individual toxicants are present at seemingly harmless concentrations.
Keywords: morje, analizna kemija, biologija, evtrofikacija, hranilne snovi, fitoplankton, onesnaževanje, Piranski zaliv
Published in DiRROS: 02.08.2024; Views: 389; Downloads: 303
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