1. Integration of multi-omics data and deep phenotyping provides insights into responses to single and combined abiotic stress in potatoMaja Zagorščak, Lamis Abdelhakim, Natalia Yaneth Rodriguez-Granados, Carissa Bleker, Andrej Blejec, Jan Zrimec, Špela Baebler, Anže Županič, Maruša Pompe Novak, Kristina Gruden, 2025, izvirni znanstveni članek Povzetek: Potato (Solanum tuberosum) is highly water and space efficient but susceptible to abiotic stresses such as heat, drought, and flooding, which are severely exacerbated by climate change. Our understanding of crop acclimation to abiotic stress, however, remains limited. Here, we present a comprehensive molecular and physiological high-throughput profiling of potato (Solanum tuberosum, cv. Désirée) under heat, drought, and waterlogging applied as single stresses or in combinations designed to mimic realistic future scenarios. Stress responses were monitored via daily phenotyping and multi-omics analyses of leaf samples comprising proteomics, targeted transcriptomics, metabolomics, and hormonomics at several timepoints during and after stress treatments. Additionally, critical metabolites of tuber samples were analyzed at the end of the stress period. We performed integrative multi-omics data analysis using a bioinformatic pipeline that we established based on machine learning and knowledge networks. Waterlogging produced the most immediate and dramatic effects on potato plants, interestingly activating ABA responses similar to drought stress. In addition, we observed distinct stress signatures at multiple molecular levels in response to heat or drought and to a combination of both. In response to all treatments, we found a downregulation of photosynthesis at different molecular levels, an accumulation of minor amino acids, and diverse stress-induced hormones. Our integrative multi-omics analysis provides global insights into plant stress responses, facilitating improved breeding strategies toward climate-adapted potato varieties. Ključne besede: potato, Solanum tuberosum, abiotic stress responses, heat, drought, waterlogging, multi-omics, integrative omics, adaptomics, panomics Objavljeno v DiRROS: 14.04.2025; Ogledov: 161; Prenosov: 127
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2. Changes in cuticle structure during growth in two terrestrial isopods (Crustacea: Isopoda: Oniscidea)Miloš Vittori, Katarina Vodnik, Andrej Blejec, 2020, izvirni znanstveni članek Povzetek: Terrestrial isopods are a successful group of terrestrial crustaceans. Their exoskeletal cuticle has been studied in several species. However, it is not known whether the cuticle of these animals becomes thicker or how its structure changes as the animals grow. We aimed to determine the principles of upscaling of the exoskeletal cuticle during growth in the terrestrial isopods Armadillidium vulgare (Latreille, 1804) and Porcellio scaber Latreille, 1804 with scanning electron microscopy. The tergal cuticle becomes thicker with increasing body length. In A. vulgare, which rolls into a ball in defense against predators, the rate of increase of tergite thickness was greater than in P. scaber, which clings to the substrate when threatened. As the cuticles of both species become thicker, the proportion of the endocuticle in the cuticle increases. There is a strong correlation between cuticle thickness and the thickness of endocuticular lamellae. This indicates that in thicker cuticles, chitin-protein fibers in sequential layers change their orientation by a smaller angle. We found no significant differences in morphometric parameters between the cuticles of A. vulgare and P. scaber when controlling for cuticle thickness. This suggests that known differences in cuticle structure and composition between these two species may result from differences in cuticle thickness.
Ključne besede: development, exoskeleton, morphometry, ultrastructure, woodlice Objavljeno v DiRROS: 04.03.2025; Ogledov: 366; Prenosov: 125
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3. A "crossomics" study analysing variability of different components in peripheral blood of health caucasoid individualsKristina Gruden, Matjaž Hren, Ana Herman, Andrej Blejec, Tanja Albrecht, Joachim Selbig, Chris Bauer, Jochannes Schuchardt, Michal Or-Guil, Klemen Zupančič, Urban Švajger, Borut Štabuc, Alojz Ihan, Andreja Nataša Kopitar, Maja Ravnikar, Miomir Knežević, Primož Rožman, Matjaž Jeras, 2012, izvirni znanstveni članek Povzetek: Background: Different immunotherapy approaches for the treatment of cancer andautoimmune diseases are being developed and tested in clinical studies worldwide. Their resulting complex experimental data should be properly evaluated, therefore reliable normal healthy control baseline values are indispensable. Methodology/Principal Findings: To assess intra- and inter-individual variability of various biomarkers, peripheral blood of 16 age and gender equilibrated healthy volunteers was sampled on 3 different days within a period of one month. Complex ććcrossomicsćć analyses of plasma metabolite profiles, antibody concentrations and lymphocyte subset counts as well as whole genome expression profiling in CD4+T and NK cells were performed. Some of the observed age, gender and BMI dependences are in agreement with the existing knowledge, like negative correlation between sex hormone levels and age or BMI related increase in lipids and soluble sugars. Thus we can assume that the distribution of all 39.743 analysed markers is well representing the normal Caucasoid population. All lymphocyte subsets, 20% of metabolites and less than 10% of genes, were identified as highly variable in our dataset. Conclusions/Significance: Our study shows that the intra-individual variability was at least two-fold lower compared to the inter-individual one at all investigated levels, showing the importance of personalised medicine approach from yet another perspective. Objavljeno v DiRROS: 04.03.2025; Ogledov: 166; Prenosov: 140
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4. Dynamics of responses in compatible potato - potato virus Y interaction are modulated by salicylic acidŠpela Baebler, Katja Stare, Maja Kovač, Andrej Blejec, Nina Prezelj, Tjaša Stare, Polona Kogovšek, Maruša Pompe Novak, S. Rosahl, Maja Ravnikar, Kristina Gruden, 2011, izvirni znanstveni članek Povzetek: To investigate the dynamics of the potato – Potato virus Y (PVY) compatible interaction in relation to salicylic acid - controlled pathways we performed experiments using non-transgenic potato cv. Désirée, transgenic NahG-Désirée, cv. Igor and PVYNTN, the most aggressive strain of PVY. The importance of salicylic acid in viral multiplication and symptom development was confirmed by pronounced symptom development in NahG-Désirée, depleted in salicylic acid, and reversion of the effect after spraying with 2,6-dichloroisonicotinic acid (a salicylic acid - analogue). We have employed quantitative PCR for monitoring virus multiplication, as well as plant responses through expression of selected marker genes of photosynthetic activity, carbohydrate metabolism and the defence response. Viral multiplication was the slowest in inoculated potato of cv. Désirée, the only asymptomatic genotype in the study. The intensity of defence-related gene expression was much stronger in both sensitive genotypes (NahG-Désirée and cv. Igor) at the site of inoculation than in asymptomatic plants (cv. Désirée). Photosynthesis and carbohydrate metabolism gene expression differed between the symptomatic and asymptomatic phenotypes. The differential gene expression pattern of the two sensitive genotypes indicates that the outcome of the interaction does not rely simply on one regulatory component, but similar phenotypical features can result from distinct responses at the molecular level.
Ključne besede: plant viruses, plant diseases Objavljeno v DiRROS: 04.03.2025; Ogledov: 211; Prenosov: 92
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5. An international comparability study on quantification of mRNA gene expression ratios: CCQM-P103.1Alison S. Devonshire, Tina Demšar, Jana Žel, Andrej Blejec, Mojca Milavec, 2016, izvirni znanstveni članek Povzetek: Measurement of RNA can be used to study and monitor a range of infectious and non-communicable diseases, with profiling of multiple gene expression mRNA transcripts being increasingly applied to cancer stratification and prognosis. An international comparison study (Consultative Committee for Amount of Substance (CCQM)-P103.1) was performed in order to evaluate the comparability of measurements of RNA copy number ratio for multiple gene targets between two samples. Six exogenous synthetic targets comprising of External RNA Control Consortium (ERCC) standards were measured alongside transcripts for three endogenous gene targets present in the background of human cell line RNA. The study was carried out under the auspices of the Nucleic Acids (formerly Bioanalysis) Working Group of the CCQM. It was coordinated by LGC (United Kingdom) with the support of National Institute of Standards and Technology (USA) and results were submitted from thirteen National Metrology Institutes and Designated Institutes. The majority of laboratories performed RNA measurements using RT-qPCR, with datasets also being submitted by two laboratories based on reverse transcription digital polymerase chain reaction and one laboratory using a next-generation sequencing method. In RT-qPCR analysis, the RNA copy number ratios between the two samples were quantified using either a standard curve or a relative quantification approach. In general, good agreement was observed between the reported results of ERCC RNA copy number ratio measurements. Measurements of the RNA copy number ratios for endogenous genes between the two samples were also consistent between the majority of laboratories. Some differences in the reported values and confidence intervals (‘measurement uncertainties’) were noted which may be attributable to choice of measurement method or quantification approach. This highlights the need for standardised practices for the calculation of fold change ratios and uncertainties in the area of gene expression profiling.
Ključne besede: RNA copy number ratio, RT-qPCR, gene expression, normalisation, standardisation, molecular diagnostic, transcriptomics, cancer, diagnostics, biomarker identification and validation Objavljeno v DiRROS: 04.03.2025; Ogledov: 175; Prenosov: 77
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6. Gene expression profiling of recombinant protein producing E. coli at suboptimal growth temperatureMitja Mahnič, Špela Baebler, Andrej Blejec, Špela Jalen, Kristina Gruden, Viktor Menart, Simona Jevševar, 2012, izvirni znanstveni članek Povzetek: Recent studies have revealed that at lower cultivation temperatures (25 °C) much higher percentage of correctly folded recombinant hG-CSF protein can be extracted from inclusion bodies. Hence, the goal of our research was to investigate mechanisms determining characteristics of non-classical inclusion bodies production using gene expression profiling, focusing on proteases and chaperones gene expression. Statistical analysis of microarray data showed prominent changes in energy metabolism, in metabolism of amino acids and nucleotides, as well as in biosynthesis of cofactors and secondary metabolites if the culture was grown below its optimal temperature. Moreover, 24 differentially expressed up to now known genes classified among proteases, chaperones and other heat or stress related genes. Among chaperones UspE and among proteases YaeL and YeaZ might play an important role in accumulation of correctly folded recombinant proteins. Membrane localized protease yaeL gene was found to have higher activity at 25 °C and is thus potentially functionally related to the more efficient recombinant protein production at lower temperatures. The results of this study represent advance in the understanding of recombinant protein production in E. coli. Genes potentially influencing production of recombinant protein at lower growth temperature represent basis for further research towards improvement of E. coli production strains as well as fermentation process. Ključne besede: recombinant protein production, non-classical inclusion bodies, expression microarrays, YaeL protease, GroEL chaperone Objavljeno v DiRROS: 05.08.2024; Ogledov: 731; Prenosov: 535
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7. Identification of plasma biomarker candidates in glioblastoma using an antibody-array-based proteomic approachKlemen Zupančič, Marjan Koršič, Urška Verbovšek, Primož Rožman, Tamara Lah Turnšek, Andrej Blejec, Kristina Gruden, Helena Motaln, Miomir Knežević, Matija Veber, Ana Herman, 2014, izvirni znanstveni članek Povzetek: Background. Glioblastoma multiforme (GBM) is a brain tumour with a very high patient mortality rate, with a median survival of 47 weeks. This might be improved by the identification of novel diagnostic, prognostic and predictive
therapy-response biomarkers, preferentially through the monitoring of the patient blood. The aim of this study was to define the impact of GBM in terms of alterations of the plasma protein levels in these patients.
Materials and methods. We used a commercially available antibody array that includes 656 antibodies to analyse
blood plasma samples from 17 healthy volunteers in comparison with 17 blood plasma samples from patients with
GBM.
Results. We identified 11 plasma proteins that are statistically most strongly associated with the presence of GBM.
These proteins belong to three functional signalling pathways: T-cell signalling and immune responses; cell adhesion and migration; and cell-cycle control and apoptosis. Thus, we can consider this identified set of proteins as potential diagnostic biomarker candidates for GBM. In addition, a set of 16 plasma proteins were significantly associated with the overall survival of these patients with GBM. Guanine nucleotide binding protein alpha (GNAO1) was associated with both GBM presence and survival of patients with GBM.
Conclusions. Antibody array analysis represents a useful tool for the screening of plasma samples for potential cancer biomarker candidates in small-scale exploratory experiments; however, clinical validation of these candidates requires their further evaluation in a larger study on an independent cohort of patients. Ključne besede: glioblastoma, proteomics, biomarker Objavljeno v DiRROS: 02.08.2024; Ogledov: 563; Prenosov: 440
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8. Reverse transcriptase droplet digital PCR shows high resilience to PCR inhibitors from plant, soil and water samplesNejc Rački, Tanja Dreo, Ion Gutiérrez-Aguirre, Andrej Blejec, Maja Ravnikar, 2014, izvirni znanstveni članek Povzetek: 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. Ključne besede: PCR amplification, inhibition, qPCR, droplet digital PCR, environmental samples Objavljeno v DiRROS: 02.08.2024; Ogledov: 533; Prenosov: 286
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9. Transcriptome study and identification of potential marker genes related to the stable expression of recombinant proteins in CHO clonesAndrej Blejec, Marjanca Blas, Petra Nikolić, Dominik Gaser, Kristina Gruden, Aleš Belič, Špela Baebler, Uroš Jamnikar, Andrej Francky, Holger Laux, 2015, izvirni znanstveni članek Povzetek: Background
Chinese hamster ovary (CHO) cells have become the host of choice for the production of recombinant proteins, due to their capacity for correct protein folding, assembly, and posttranslational modifications. The most widely used system for recombinant proteins is the gene amplification procedure that uses the CHO-Dhfr expression system. However, CHO cells are known to have a very unstable karyotype. This is due to chromosome rearrangements that can arise from translocations and homologous recombination, especially when cells with the CHO-Dhfr expression system are treated with methotrexate hydrate. The present method used in the industry for testing clones for their long-term stability of recombinant protein production is empirical, and it involves their cultivation over extended periods of time prior to the selection of the most suitable clone for further bioprocess development. The aim of the present study was the identification of marker genes that can predict stable expression of recombinant genes in particular clones early in the development stage.
Results
The transcriptome profiles of CHO clones with stable and unstable recombinant protein production were investigated over 10-weeks of cultivation, using a DNA microarray. We identified 14 genes that were differentially expressed between the stable and unstable clones already at 2 weeks from the beginning of the cultivation. Their expression was validated by reverse-transcription quantitative real-time PCR (RT-qPCR). Furthermore, the k-nearest neighbour algorithm approach shows that the combination of the gene expression patterns of only five of these 14 genes is sufficient to predict stable recombinant protein production in clones in the early phases of cell-line development.
Conclusions
The exact molecular mechanisms that cause unstable recombinant protein production are not fully understood. However, the expression profiles of some genes in clones with stable and unstable recombinant protein production allow prediction of such instability early in the cell-line development stage. We have thus developed a proof-of-concept for a novel approach to eliminate unstable clones in the CHO-Dhfr expression system, which saves time and labour-intensive work in cell-line development. Ključne besede: CHO cell line, stable recombinant protein production, gene expression, RT-qPCR, DNA microarray, mMarker genes Objavljeno v DiRROS: 29.07.2024; Ogledov: 603; Prenosov: 458
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10. The effect of timing of female vibrational reply on male signalling and searching behaviour in the leafhopper Aphrodes makaroviMeta Virant-Doberlet, Maarten De Groot, Andrej Blejec, Ana Kuhelj, 2015, izvirni znanstveni članek Povzetek: Sexual communication in animals often involves duetting characterized by a coordinated reciprocal exchange of acoustic signals. We used playback experiments to study the role of timing of a female reply in the species-specific duet structure in the leafhopper Aphrodes makarovi (Hemiptera: Cicadellidae). In leafhoppers, mate recognition and location is mediated exclusively by species- and sex-specific substrate-borne vibrational signals and a female signal emitted in reply to male advertisement calls is essential for recognition and successful location of the female. In A. makarovi, males have to initiate each exchange of vibrational signals between partners, and in a duet the beginning of a female reply overlaps the end of the male advertisement call. Results of playback treatments in which female replies were delayed and did not overlap with the male call revealed that in order to trigger an appropriate behavioural response of the male, female reply has to appear in a period less than 400 ms after the end of the initiating male call. Results also suggest that males are not able to detect a female reply while calling, since female reply that did not continue after the end of male call triggered male behaviour similar to behaviour observed in the absence of female reply. Together, our results show that vibrational duets are tightly coordinated and that the species-specific duet structure plays an important role in mate recognition in location processes. Ključne besede: vibration, insects, bioacoustics, animal signaling and communication Objavljeno v DiRROS: 29.07.2024; Ogledov: 507; Prenosov: 324
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