Polona Kogovšek - Academia.edu (original) (raw)
Papers by Polona Kogovšek
Extracellular vesicle-bound DNA (evDNA) is an understudied extracellular vesicle (EV) cargo, part... more Extracellular vesicle-bound DNA (evDNA) is an understudied extracellular vesicle (EV) cargo, particularly in cancer-unrelated fundamental and biomarker research. Although evDNA has been detected in urine, little is known about its characteristics, localization, and biomarker potential for kidney pathologies. To address this, we enriched EVs from urine of well-characterized kidney transplant recipients undergoing allograft biopsy, characterized their evDNA and its association to allograft injury. Using DNase treatment and immunogold labelling TEM, we show that DNA is bound to the surface of urinary EVs. Although the urinary evDNA and cell-free DNA correlated in several characteristics, the DNA integrity index showed evDNA was less fragmented (P < 0.001). Urinary EVs from patients with rejection and non-rejection allograft injury were significantly larger (mean: P = 0.045, median: P = 0.031) and have bound more DNA as measured by normalized evDNA yield (P = 0.018) and evDNA copy nu...
Toxins, 2021
Due to increased frequency of cyanobacterial blooms and emerging evidence of cyanotoxicity in bio... more Due to increased frequency of cyanobacterial blooms and emerging evidence of cyanotoxicity in biofilm, reliable methods for early cyanotoxin threat detection are of major importance for protection of human, animal and environmental health. To complement the current methods of risk assessment, this study aimed to evaluate selected qPCR assays for detection of potentially toxic cyanobacteria in environmental samples. In the course of one year, 25 plankton and 23 biofilm samples were collected from 15 water bodies in Slovenia. Three different analyses were performed and compared to each other; qPCR targeting mcyE, cyrJ and sxtA genes involved in cyanotoxin production, LC-MS/MS quantifying microcystin, cylindrospermopsin and saxitoxin concentration, and microscopic analyses identifying potentially toxic cyanobacterial taxa. qPCR analyses detected potentially toxic Microcystis in 10 lake plankton samples, and potentially toxic Planktothrix cells in 12 lake plankton and one lake biofilm s...
Toxins, 2021
Due to increased frequency of cyanobacterial blooms and emerging evidence of cyanotoxicity in bio... more Due to increased frequency of cyanobacterial blooms and emerging evidence of cyanotoxicity in biofilm, reliable methods for early cyanotoxin threat detection are of major importance for protection of human, animal and environmental health. To complement the current methods of risk assessment, this study aimed to evaluate selected qPCR assays for detection of potentially toxic cyanobacteria in environmental samples. In the course of one year, 25 plankton and 23 biofilm samples were collected from 15 water bodies in Slovenia. Three different analyses were performed and compared to each other; qPCR targeting mcyE, cyrJ and sxtA genes involved in cyanotoxin production, LC-MS/MS quantifying microcystin, cylindrospermopsin and saxitoxin concentration, and microscopic analyses identifying potentially toxic cyanobacterial taxa. qPCR analyses detected potentially toxic Microcystis in 10 lake plankton samples, and potentially toxic Planktothrix cells in 12 lake plankton and one lake biofilm s...
Molecules, 2021
Early diagnosis with rapid detection of the virus plays a key role in preventing the spread of in... more Early diagnosis with rapid detection of the virus plays a key role in preventing the spread of infection and in treating patients effectively. In order to address the need for a straightforward detection of SARS-CoV-2 infection and assessment of viral spread, we developed rapid, sensitive, extraction-free one-step reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and reverse transcription loop-mediated isothermal amplification (RT-LAMP) tests for detecting SARS-CoV-2 in saliva. We analyzed over 700 matched pairs of saliva and nasopharyngeal swab (NSB) specimens from asymptomatic and symptomatic individuals. Saliva, as either an oral cavity swab or passive drool, was collected in an RNA stabilization buffer. The stabilized saliva specimens were heat-treated and directly analyzed without RNA extraction. The diagnostic sensitivity of saliva-based RT-qPCR was at least 95% in individuals with subclinical infection and outperformed RT-LAMP, which had at least 70% sens...
Frontiers in Microbiology, 2019
One of the main challenges in the gene therapy viral vector development is to establish an optimi... more One of the main challenges in the gene therapy viral vector development is to establish an optimized process for its large scale production. This requires optimization for upstream and downstream processes as well as methods that enable the step-by step analytical characterization of the virus, the results of which inform the iterative refinement of production for yield, purity and potency. The biggest problem here is a plethora of viral vector formulations, many of which interfere with analytical techniques. We took adeno-associated virus (AAV) as an example and showed benefits of combined use of molecular methods and transmission electron microscopy (TEM) for viral vectors' characterization and quantification. Results of the analyses showed that droplet digital PCR (ddPCR) performs better than quantitative real-time PCR (qPCR), in terms of robustness and assay variance, and this was especially relevant for partially purified (in-process) samples. Moreover, we demonstrate the importance of sample preparation prior to PCR analysis. We evaluated viral structure, presence of aggregates and impurities with TEM analysis and found that these impacted the differences in viral titers observed by qPCR and ddPCR and could be altered by sample preparation. These results serve as a guide for the establishment of the analytical methods required to provide measures of identity and purity for AAV viral vectors.
Plant Pathology, 2017
Waterborne and seed-borne Pepino mosaic virus (PepMV) and Potato spindle tuber viroid (PSTVd) pos... more Waterborne and seed-borne Pepino mosaic virus (PepMV) and Potato spindle tuber viroid (PSTVd) pose serious threats to tomato production due to seed transmission and mechanical transmission, coupled with their long-term stability outside the host plant. Therefore, rapid and sensitive diagnostic procedures are needed to prevent the spread of these quarantine pathogens. In particular, water and seed contamination are difficult to detect and confirm without efficient concentration methods. In this study, we present procedures that improve detection of PSTVd from tomato seeds and leaf tissue, and PepMV from water and tomato leaf tissue. For efficient concentration of PepMV from water samples, we optimised a procedure using convective interaction media monolithic chromatography columns, which provides concentration by three orders of magnitude. For concentration of PSTVd from seed extracts, we developed an easy-to-use and efficient method based on RNA binding to positively charged anion-exchange resin beads that provides up to 100-fold more sensitive detection in comparison with procedure without concentration step. This thus allows confirmation of RT-qPCR results with sequencing of RT-PCR products in samples with low viroid levels. In addition, reverse-transcription loop-mediated isothermal amplification assays for detection of PSTVd and PepMV were optimised and adapted to both laboratory and onsite testing requirements. This allows rapid detection of these pathogens in crude leaf homogenates, in <30 min. These procedures of concentration and detection are shown to be efficient and to fill the gaps in diagnostics of PepMV and PSTVd, especially when these pathogens are present at low levels in difficult matrices, like water and seeds.
European Journal of Plant Pathology, 2017
Bois noir (BN) is the most widespread European grapevine yellows disease caused by 'Candidatus Ph... more Bois noir (BN) is the most widespread European grapevine yellows disease caused by 'Candidatus Phytoplasma solani'. Although our knowledge of the mechanisms of interactions of this pathogenic bacteria with host is largely unknown, the plant-pathogen system of BN is commonly used as a model system for studying grapevine yellows diseases. We applied here a conceptual model of general plant pathologya disease triangle for describing interactions among the host plant, the pathogen and the environment. We generated a proofof-concept statistical model for disease triangle using original experimental data and different statistical and data mining approaches for a selected system of 'Ca. P. solani' infection of cv. 'Chardonnay' grapevine plants. We monitored individual plants from a single vineyard over a period of six years. Phytoplasma content, the expression of 21 selected grapevine genes and environmental conditions were recorded and related to disease severity. Our model predicts that in described conditions BN is a function of the expression of grapevine gene VvDMR6, summer rainfall and abundance of 'Ca. P. solani'. The greatest impact among elements of the disease triangle is attributed to the pathogen, and is independent of the pathogen titer. We showed that this first de facto representation of the disease triangle is useful for showing disease dynamics over several years and could be applied to other plant-pathogen systems. The overall results of this study will contribute to understanding of 'Ca. P. solani' biology and its interactions with grapevine host.
European Journal of Plant Pathology, 2017
Bois noir (BN) is the most widespread European grapevine yellows disease caused by 'Candidatus Ph... more Bois noir (BN) is the most widespread European grapevine yellows disease caused by 'Candidatus Phytoplasma solani'. Although our knowledge of the mechanisms of interactions of this pathogenic bacteria with host is largely unknown, the plant-pathogen system of BN is commonly used as a model system for studying grapevine yellows diseases. We applied here a conceptual model of general plant pathologya disease triangle for describing interactions among the host plant, the pathogen and the environment. We generated a proofof-concept statistical model for disease triangle using original experimental data and different statistical and data mining approaches for a selected system of 'Ca. P. solani' infection of cv. 'Chardonnay' grapevine plants. We monitored individual plants from a single vineyard over a period of six years. Phytoplasma content, the expression of 21 selected grapevine genes and environmental conditions were recorded and related to disease severity. Our model predicts that in described conditions BN is a function of the expression of grapevine gene VvDMR6, summer rainfall and abundance of 'Ca. P. solani'. The greatest impact among elements of the disease triangle is attributed to the pathogen, and is independent of the pathogen titer. We showed that this first de facto representation of the disease triangle is useful for showing disease dynamics over several years and could be applied to other plant-pathogen systems. The overall results of this study will contribute to understanding of 'Ca. P. solani' biology and its interactions with grapevine host.
PloS one, 2016
Potato production is one of the most important agricultural sectors, and it is challenged by vari... more Potato production is one of the most important agricultural sectors, and it is challenged by various detrimental factors, including virus infections. To control losses in potato production, knowledge about the virus-plant interactions is crucial. Here, we investigated the molecular processes in potato plants as a result of Potato virus Y (PVY) infection, the most economically important potato viral pathogen. We performed an integrative study that links changes in the metabolome and gene expression in potato leaves inoculated with the mild PVYN and aggressive PVYNTN isolates, for different times through disease development. At the beginning of infection (1 day post-inoculation), virus-infected plants showed an initial decrease in the concentrations of metabolites connected to sugar and amino-acid metabolism, the TCA cycle, the GABA shunt, ROS scavangers, and phenylpropanoids, relative to the control plants. A pronounced increase in those metabolites was detected at the start of the s...
FEMS microbiology letters, 2015
The opportunistic pathogen Pseudomonas aeruginosa uses quorum-sensing systems to regulate collect... more The opportunistic pathogen Pseudomonas aeruginosa uses quorum-sensing systems to regulate collective behaviour in response to the environment, by linking the expression of particular genes to population density. The quorum-sensing transcription factors LasR and RhlR and their cognate N-acyl-homoserine lactone (HSL) signals N-3-oxo-dodecanoyl-L-HSL (3OC12-HSL) and N-butanoyl-L-HSL (C4-HSL) control the expression of several hundred genes, which include those involved in virulence and biofilm formation. Here, we have focused on regulation of the expression of the putative virulence factor gene, rahU. We show that the intact las-rhl box immediately upstream of the -35 promoter element is needed for rahU expression in P. aeruginosa. Using β-galactosidase assays and quantification of the mRNA levels for rahU, lasR and rhlR, we provide evidence that for rahU promoter activity, 3OC12-HSL-LasR is not sufficient, and instead C4-HSL-RhlR is the trigger. Furthermore, surface plasmon resonance a...
Plant Pathology, 2010
Differences in the early responses of two potato cultivars, Igor and Nadine, to two isolates of P... more Differences in the early responses of two potato cultivars, Igor and Nadine, to two isolates of Potato virus Y (PVY), the aggressive PVY NTN and the mild PVY N , were monitored. Microarray and quantitative real-time PCR analyses were carried out to identify differentially expressed genes after inoculation with each virus isolate. Additionally, symptom severity and development was observed and the amount of virus isolate accumulated in systemically infected leaves was evaluated, where a significantly higher amount of PVY NTN was detected. Microarray analysis revealed 572, 1288 and 1706 differentially expressed genes at 0AE5, 12 and 48 h post-inoculation, respectively in cv. Igor, with a similar pattern observed in cv. Nadine. Microarray and quantitative real-time PCR results implied an earlier accumulation of sugars and lower photosynthesis in leaves inoculated with the aggressive isolate than in leaves inoculated with the mild isolate. The PVY NTN isolate did not activate early differential expression of the Fe-superoxide dismutase and pectin methylesterase inhibitor (PMEI) genes, indicating a delay in plant response relative to that following PVY N inoculation. Differences in the expression of the b-glucanase-I gene were also observed in early plant responses to inoculation with each virus isolate.
Strojniški vestnik - Journal of Mechanical Engineering, 2022
Face coverings, such as surgical masks and respirators, have an important role in preventing bact... more Face coverings, such as surgical masks and respirators, have an important role in preventing bacterial and viral transmission, especially during a global pandemic like COVID-19. Therefore, to secure their availability, new manufacturers and the use of novel materials must be encouraged. However, masks and their materials must first be properly tested for safety and efficiency, as required by the relevant standard, valid in a specific region. All standards prescribe determination of the bacterial filtration efficiency (BFE) of masks. In this study, we report the establishment of a test method for the BFE of face masks in accordance with European standard EN 14683:2019, by which we tested 52 samples, each composed of 3 to 5 subsamples, of surgical and cloth masks, respirators, filters, and mask materials. Forty-seven out of the 52 samples reached a BFE above 75 %. Of these, 16 samples had a BFE of 75 % to 95 %, 3 had a BFE of 95 % to 98 %, while 28 reached a filtration efficiency abov...
Extracellular vesicle-bound DNA (evDNA) is an understudied extracellular vesicle (EV) cargo, part... more Extracellular vesicle-bound DNA (evDNA) is an understudied extracellular vesicle (EV) cargo, particularly in cancer-unrelated fundamental and biomarker research. Although evDNA has been detected in urine, little is known about its characteristics, localization, and biomarker potential for kidney pathologies. To address this, we enriched EVs from urine of well-characterized kidney transplant recipients undergoing allograft biopsy, characterized their evDNA and its association to allograft injury. Using DNase treatment and immunogold labelling TEM, we show that DNA is bound to the surface of urinary EVs. Although the urinary evDNA and cell-free DNA correlated in several characteristics, the DNA integrity index showed evDNA was less fragmented (P < 0.001). Urinary EVs from patients with rejection and non-rejection allograft injury were significantly larger (mean: P = 0.045, median: P = 0.031) and have bound more DNA as measured by normalized evDNA yield (P = 0.018) and evDNA copy nu...
Toxins, 2021
Due to increased frequency of cyanobacterial blooms and emerging evidence of cyanotoxicity in bio... more Due to increased frequency of cyanobacterial blooms and emerging evidence of cyanotoxicity in biofilm, reliable methods for early cyanotoxin threat detection are of major importance for protection of human, animal and environmental health. To complement the current methods of risk assessment, this study aimed to evaluate selected qPCR assays for detection of potentially toxic cyanobacteria in environmental samples. In the course of one year, 25 plankton and 23 biofilm samples were collected from 15 water bodies in Slovenia. Three different analyses were performed and compared to each other; qPCR targeting mcyE, cyrJ and sxtA genes involved in cyanotoxin production, LC-MS/MS quantifying microcystin, cylindrospermopsin and saxitoxin concentration, and microscopic analyses identifying potentially toxic cyanobacterial taxa. qPCR analyses detected potentially toxic Microcystis in 10 lake plankton samples, and potentially toxic Planktothrix cells in 12 lake plankton and one lake biofilm s...
Toxins, 2021
Due to increased frequency of cyanobacterial blooms and emerging evidence of cyanotoxicity in bio... more Due to increased frequency of cyanobacterial blooms and emerging evidence of cyanotoxicity in biofilm, reliable methods for early cyanotoxin threat detection are of major importance for protection of human, animal and environmental health. To complement the current methods of risk assessment, this study aimed to evaluate selected qPCR assays for detection of potentially toxic cyanobacteria in environmental samples. In the course of one year, 25 plankton and 23 biofilm samples were collected from 15 water bodies in Slovenia. Three different analyses were performed and compared to each other; qPCR targeting mcyE, cyrJ and sxtA genes involved in cyanotoxin production, LC-MS/MS quantifying microcystin, cylindrospermopsin and saxitoxin concentration, and microscopic analyses identifying potentially toxic cyanobacterial taxa. qPCR analyses detected potentially toxic Microcystis in 10 lake plankton samples, and potentially toxic Planktothrix cells in 12 lake plankton and one lake biofilm s...
Molecules, 2021
Early diagnosis with rapid detection of the virus plays a key role in preventing the spread of in... more Early diagnosis with rapid detection of the virus plays a key role in preventing the spread of infection and in treating patients effectively. In order to address the need for a straightforward detection of SARS-CoV-2 infection and assessment of viral spread, we developed rapid, sensitive, extraction-free one-step reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and reverse transcription loop-mediated isothermal amplification (RT-LAMP) tests for detecting SARS-CoV-2 in saliva. We analyzed over 700 matched pairs of saliva and nasopharyngeal swab (NSB) specimens from asymptomatic and symptomatic individuals. Saliva, as either an oral cavity swab or passive drool, was collected in an RNA stabilization buffer. The stabilized saliva specimens were heat-treated and directly analyzed without RNA extraction. The diagnostic sensitivity of saliva-based RT-qPCR was at least 95% in individuals with subclinical infection and outperformed RT-LAMP, which had at least 70% sens...
Frontiers in Microbiology, 2019
One of the main challenges in the gene therapy viral vector development is to establish an optimi... more One of the main challenges in the gene therapy viral vector development is to establish an optimized process for its large scale production. This requires optimization for upstream and downstream processes as well as methods that enable the step-by step analytical characterization of the virus, the results of which inform the iterative refinement of production for yield, purity and potency. The biggest problem here is a plethora of viral vector formulations, many of which interfere with analytical techniques. We took adeno-associated virus (AAV) as an example and showed benefits of combined use of molecular methods and transmission electron microscopy (TEM) for viral vectors' characterization and quantification. Results of the analyses showed that droplet digital PCR (ddPCR) performs better than quantitative real-time PCR (qPCR), in terms of robustness and assay variance, and this was especially relevant for partially purified (in-process) samples. Moreover, we demonstrate the importance of sample preparation prior to PCR analysis. We evaluated viral structure, presence of aggregates and impurities with TEM analysis and found that these impacted the differences in viral titers observed by qPCR and ddPCR and could be altered by sample preparation. These results serve as a guide for the establishment of the analytical methods required to provide measures of identity and purity for AAV viral vectors.
Plant Pathology, 2017
Waterborne and seed-borne Pepino mosaic virus (PepMV) and Potato spindle tuber viroid (PSTVd) pos... more Waterborne and seed-borne Pepino mosaic virus (PepMV) and Potato spindle tuber viroid (PSTVd) pose serious threats to tomato production due to seed transmission and mechanical transmission, coupled with their long-term stability outside the host plant. Therefore, rapid and sensitive diagnostic procedures are needed to prevent the spread of these quarantine pathogens. In particular, water and seed contamination are difficult to detect and confirm without efficient concentration methods. In this study, we present procedures that improve detection of PSTVd from tomato seeds and leaf tissue, and PepMV from water and tomato leaf tissue. For efficient concentration of PepMV from water samples, we optimised a procedure using convective interaction media monolithic chromatography columns, which provides concentration by three orders of magnitude. For concentration of PSTVd from seed extracts, we developed an easy-to-use and efficient method based on RNA binding to positively charged anion-exchange resin beads that provides up to 100-fold more sensitive detection in comparison with procedure without concentration step. This thus allows confirmation of RT-qPCR results with sequencing of RT-PCR products in samples with low viroid levels. In addition, reverse-transcription loop-mediated isothermal amplification assays for detection of PSTVd and PepMV were optimised and adapted to both laboratory and onsite testing requirements. This allows rapid detection of these pathogens in crude leaf homogenates, in <30 min. These procedures of concentration and detection are shown to be efficient and to fill the gaps in diagnostics of PepMV and PSTVd, especially when these pathogens are present at low levels in difficult matrices, like water and seeds.
European Journal of Plant Pathology, 2017
Bois noir (BN) is the most widespread European grapevine yellows disease caused by 'Candidatus Ph... more Bois noir (BN) is the most widespread European grapevine yellows disease caused by 'Candidatus Phytoplasma solani'. Although our knowledge of the mechanisms of interactions of this pathogenic bacteria with host is largely unknown, the plant-pathogen system of BN is commonly used as a model system for studying grapevine yellows diseases. We applied here a conceptual model of general plant pathologya disease triangle for describing interactions among the host plant, the pathogen and the environment. We generated a proofof-concept statistical model for disease triangle using original experimental data and different statistical and data mining approaches for a selected system of 'Ca. P. solani' infection of cv. 'Chardonnay' grapevine plants. We monitored individual plants from a single vineyard over a period of six years. Phytoplasma content, the expression of 21 selected grapevine genes and environmental conditions were recorded and related to disease severity. Our model predicts that in described conditions BN is a function of the expression of grapevine gene VvDMR6, summer rainfall and abundance of 'Ca. P. solani'. The greatest impact among elements of the disease triangle is attributed to the pathogen, and is independent of the pathogen titer. We showed that this first de facto representation of the disease triangle is useful for showing disease dynamics over several years and could be applied to other plant-pathogen systems. The overall results of this study will contribute to understanding of 'Ca. P. solani' biology and its interactions with grapevine host.
European Journal of Plant Pathology, 2017
Bois noir (BN) is the most widespread European grapevine yellows disease caused by 'Candidatus Ph... more Bois noir (BN) is the most widespread European grapevine yellows disease caused by 'Candidatus Phytoplasma solani'. Although our knowledge of the mechanisms of interactions of this pathogenic bacteria with host is largely unknown, the plant-pathogen system of BN is commonly used as a model system for studying grapevine yellows diseases. We applied here a conceptual model of general plant pathologya disease triangle for describing interactions among the host plant, the pathogen and the environment. We generated a proofof-concept statistical model for disease triangle using original experimental data and different statistical and data mining approaches for a selected system of 'Ca. P. solani' infection of cv. 'Chardonnay' grapevine plants. We monitored individual plants from a single vineyard over a period of six years. Phytoplasma content, the expression of 21 selected grapevine genes and environmental conditions were recorded and related to disease severity. Our model predicts that in described conditions BN is a function of the expression of grapevine gene VvDMR6, summer rainfall and abundance of 'Ca. P. solani'. The greatest impact among elements of the disease triangle is attributed to the pathogen, and is independent of the pathogen titer. We showed that this first de facto representation of the disease triangle is useful for showing disease dynamics over several years and could be applied to other plant-pathogen systems. The overall results of this study will contribute to understanding of 'Ca. P. solani' biology and its interactions with grapevine host.
PloS one, 2016
Potato production is one of the most important agricultural sectors, and it is challenged by vari... more Potato production is one of the most important agricultural sectors, and it is challenged by various detrimental factors, including virus infections. To control losses in potato production, knowledge about the virus-plant interactions is crucial. Here, we investigated the molecular processes in potato plants as a result of Potato virus Y (PVY) infection, the most economically important potato viral pathogen. We performed an integrative study that links changes in the metabolome and gene expression in potato leaves inoculated with the mild PVYN and aggressive PVYNTN isolates, for different times through disease development. At the beginning of infection (1 day post-inoculation), virus-infected plants showed an initial decrease in the concentrations of metabolites connected to sugar and amino-acid metabolism, the TCA cycle, the GABA shunt, ROS scavangers, and phenylpropanoids, relative to the control plants. A pronounced increase in those metabolites was detected at the start of the s...
FEMS microbiology letters, 2015
The opportunistic pathogen Pseudomonas aeruginosa uses quorum-sensing systems to regulate collect... more The opportunistic pathogen Pseudomonas aeruginosa uses quorum-sensing systems to regulate collective behaviour in response to the environment, by linking the expression of particular genes to population density. The quorum-sensing transcription factors LasR and RhlR and their cognate N-acyl-homoserine lactone (HSL) signals N-3-oxo-dodecanoyl-L-HSL (3OC12-HSL) and N-butanoyl-L-HSL (C4-HSL) control the expression of several hundred genes, which include those involved in virulence and biofilm formation. Here, we have focused on regulation of the expression of the putative virulence factor gene, rahU. We show that the intact las-rhl box immediately upstream of the -35 promoter element is needed for rahU expression in P. aeruginosa. Using β-galactosidase assays and quantification of the mRNA levels for rahU, lasR and rhlR, we provide evidence that for rahU promoter activity, 3OC12-HSL-LasR is not sufficient, and instead C4-HSL-RhlR is the trigger. Furthermore, surface plasmon resonance a...
Plant Pathology, 2010
Differences in the early responses of two potato cultivars, Igor and Nadine, to two isolates of P... more Differences in the early responses of two potato cultivars, Igor and Nadine, to two isolates of Potato virus Y (PVY), the aggressive PVY NTN and the mild PVY N , were monitored. Microarray and quantitative real-time PCR analyses were carried out to identify differentially expressed genes after inoculation with each virus isolate. Additionally, symptom severity and development was observed and the amount of virus isolate accumulated in systemically infected leaves was evaluated, where a significantly higher amount of PVY NTN was detected. Microarray analysis revealed 572, 1288 and 1706 differentially expressed genes at 0AE5, 12 and 48 h post-inoculation, respectively in cv. Igor, with a similar pattern observed in cv. Nadine. Microarray and quantitative real-time PCR results implied an earlier accumulation of sugars and lower photosynthesis in leaves inoculated with the aggressive isolate than in leaves inoculated with the mild isolate. The PVY NTN isolate did not activate early differential expression of the Fe-superoxide dismutase and pectin methylesterase inhibitor (PMEI) genes, indicating a delay in plant response relative to that following PVY N inoculation. Differences in the expression of the b-glucanase-I gene were also observed in early plant responses to inoculation with each virus isolate.
Strojniški vestnik - Journal of Mechanical Engineering, 2022
Face coverings, such as surgical masks and respirators, have an important role in preventing bact... more Face coverings, such as surgical masks and respirators, have an important role in preventing bacterial and viral transmission, especially during a global pandemic like COVID-19. Therefore, to secure their availability, new manufacturers and the use of novel materials must be encouraged. However, masks and their materials must first be properly tested for safety and efficiency, as required by the relevant standard, valid in a specific region. All standards prescribe determination of the bacterial filtration efficiency (BFE) of masks. In this study, we report the establishment of a test method for the BFE of face masks in accordance with European standard EN 14683:2019, by which we tested 52 samples, each composed of 3 to 5 subsamples, of surgical and cloth masks, respirators, filters, and mask materials. Forty-seven out of the 52 samples reached a BFE above 75 %. Of these, 16 samples had a BFE of 75 % to 95 %, 3 had a BFE of 95 % to 98 %, while 28 reached a filtration efficiency abov...