Karlovsky, Petr

[["dc.bibliographiccitation.artnumber","51"],["dc.bibliographiccitation.journal","BMC Genomics"],["dc.bibliographiccitation.volume","6"],["dc.contributor.author","Venkatesh, B."],["dc.contributor.author","Hettwer, Ursula"],["dc.contributor.author","Koopmann, Birger"],["dc.contributor.author","Karlovsky, Petr"],["dc.date.accessioned","2018-11-07T11:08:48Z"],["dc.date.available","2018-11-07T11:08:48Z"],["dc.date.issued","2005"],["dc.description.abstract","Background: Gene expression studies on non-model organisms require open-end strategies for transcription profiling. Gel-based analysis of cDNA fragments allows to detect alterations in gene expression for genes which have neither been sequenced yet nor are available in cDNA libraries. Commonly used protocols for gel-based transcript profiling are cDNA differential display (DDRT-PCR) and cDNA-AFLP. Both methods have been used merely as qualitative gene discovery tools so far. Results: We developed procedures for the conversion of cDNA Differential Display data into quantitative transcription profiles. Amplified cDNA fragments are separated on a DNA sequencer and detector signals are converted into virtual gel images suitable for semi-automatic analysis. Data processing consists of four steps: (i) cDNA bands in lanes corresponding to samples treated with the same primer combination are matched in order to identify fragments originating from the same transcript, (ii) intensity of bands is determined by densitometry, (iii) densitometric values are normalized, and (iv) intensity ratio is calculated for each pair of corresponding bands. Transcription profiles are represented by sets of intensity ratios (control vs. treatment) for cDNA fragments defined by primer combination and DNA mobility. We demonstrated the procedure by analyzing DDRT-PCR data on the effect of secondary metabolites of oilseed rape Brassica napus on the transcriptome of the pathogenic fungus Leptosphaeria maculans. Conclusion: We developed a data processing procedure for the quantitative analysis of amplified cDNA fragments separated by electrophoresis. The system utilizes common software and provides an open-end alternative to DNA microarray analysis of the transcriptome. It is expected to work equally well with DDRT-PCR and cDNA-AFLP data and be useful particularly in reseach on organisms for which microarray analysis is not available or economical."],["dc.identifier.doi","10.1186/1471-2164-6-51"],["dc.identifier.isi","000228374900001"],["dc.identifier.pmid","15807902"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/4422"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/52871"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Biomed Central Ltd"],["dc.relation.issn","1471-2164"],["dc.rights","Goescholar"],["dc.rights.uri","https://goescholar.uni-goettingen.de/licenses"],["dc.title","Conversion of cDNA differential display results (DDRT-PCR) into quantitative transcription profiles"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","350"],["dc.bibliographiccitation.issue","3"],["dc.bibliographiccitation.journal","International Journal of Food Microbiology"],["dc.bibliographiccitation.lastpage","357"],["dc.bibliographiccitation.volume","116"],["dc.contributor.author","Adejumo, Timothy O."],["dc.contributor.author","Hettwer, Ursula"],["dc.contributor.author","Karlovsky, Petr"],["dc.date.accessioned","2018-11-07T11:02:19Z"],["dc.date.available","2018-11-07T11:02:19Z"],["dc.date.issued","2007"],["dc.description.abstract","A total of 180 maize samples meant for human consumption from four maize-producing states of southwestem Nigeria were screened for twelve major Fusarium mycotoxins (trichothecenes). Mycological examination of the samples showed that Fusarium verticillioides was the most commonly isolated fungi (71%), followed by F sporotrichioides (64%), F graminearian (32%), F pallidoroseum (15%), F compactum (12%), F. equiseti (9%), F. acuminatum (8%), F. subglutinans (4%) and F. oxysportan (1%). The trichothecenes include deoxynivalenol (DON), 3, monoacetyldeoxynivalenol (3-AcDON), 15, mono-acetyldeoxynivalenol (15-AcDON), nivalenol (NfV), HT-2 toxin (HT-2), neosolaniol (NEO), T-2 toxin (T-2), T-2 tetraol and T-2 triol, diacetoxyscirpenol (DAS), MAS-monoacetoxyscirpenol (MAS) and fusarenone-X. Quantification was by high performance liquid chromatography coupled with mass spectroscopy (HPLC/MS); the detection limits for each of the mycotoxins varied between 20 and 200 mu g kg(-1). Sixty six samples (36.3%) were contaminated with trichothecenes, DON (mean: 226.2 mu g kg(-1); range: 9.6745.1 mu g kg(-1)), 3-AcDON (mean: 17.3 mu g kg(-1); range: 0.7-72.4 mu g kg(-1)) and DAS (mean: 16.0 mu g kg(-1); range: 1.0-5 1.0 mu g kg(-1)) were detected in 22%, 17% and 9% of total samples respectively. There were no 15-AcDON, NIV, HT-2, NEO, T-2, T-2 tetraol, T-2 triol, MAS and fusarenone-X detected. This is the first comprehensive report about the natural occurrence of DON, AcDON and DAS in maize for direct human consumption in Nigeria. (c) 2007 Elsevier B.V. All rights reserved."],["dc.identifier.doi","10.1016/j.ijfoodmicro.2007.02.009"],["dc.identifier.isi","000246641400008"],["dc.identifier.pmid","17412440"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/51355"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Elsevier Science Bv"],["dc.relation.issn","0168-1605"],["dc.title","Occurrence of Fusarium species and trichothecenes in Nigerian maize"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","121"],["dc.bibliographiccitation.journal","BMC Plant Biology"],["dc.bibliographiccitation.volume","11"],["dc.contributor.author","Khorassani, Reza"],["dc.contributor.author","Hettwer, Ursula"],["dc.contributor.author","Ratzinger, Astrid"],["dc.contributor.author","Steingrobe, Bernd"],["dc.contributor.author","Karlovsky, Petr"],["dc.contributor.author","Claassen, Norbert"],["dc.date.accessioned","2018-11-07T08:53:06Z"],["dc.date.available","2018-11-07T08:53:06Z"],["dc.date.issued","2011"],["dc.description.abstract","Background: In soils with a low phosphorus (P) supply, sugar beet is known to intake more P than other species such as maize, wheat, or groundnut. We hypothesized that organic compounds exuded by sugar beet roots solubilize soil P and that this exudation is stimulated by P starvation. Results: Root exudates were collected from plants grown in hydroponics under low-and high-P availability. Exudate components were separated by HPLC, ionized by electrospray, and detected by mass spectrometry in the range of mass-to-charge ratio (m/z) from 100 to 1000. Eight mass spectrometric signals were enhanced at least 5-fold by low P availability at all harvest times. Among these signals, negative ions with an m/z of 137 and 147 were shown to originate from salicylic acid and citramalic acid. The ability of both compounds to mobilize soil P was demonstrated by incubation of pure substances with Oxisol soil fertilized with calcium phosphate. Conclusions: Root exudates of sugar beet contain salicylic acid and citramalic acid, the latter of which has rarely been detected in plants so far. Both metabolites solubilize soil P and their exudation by roots is stimulated by P deficiency. These results provide the first assignment of a biological function to citramalic acid of plant origin."],["dc.description.sponsorship","Deutsche Forschungsgemeinschaft (DFG), Bonn, Germany [FOR546]"],["dc.identifier.doi","10.1186/1471-2229-11-121"],["dc.identifier.isi","000295014600001"],["dc.identifier.pmid","21871058"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/6941"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/22328"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Biomed Central Ltd"],["dc.relation.issn","1471-2229"],["dc.rights","CC BY 2.0"],["dc.rights.uri","https://creativecommons.org/licenses/by/2.0"],["dc.title","Citramalic acid and salicylic acid in sugar beet root exudates solubilize soil phosphorus"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.issue","4"],["dc.bibliographiccitation.journal","Journal of Plant Protection Research"],["dc.bibliographiccitation.volume","49"],["dc.contributor.author","Adejumo, Timothy"],["dc.contributor.author","Hettwer, Ursula"],["dc.contributor.author","Nutz, Sabine"],["dc.contributor.author","Karlovsky, Petr"],["dc.date.accessioned","2019-07-09T11:40:21Z"],["dc.date.available","2019-07-09T11:40:21Z"],["dc.date.issued","2009"],["dc.description.abstract","Eighty maize grain samples collected in Nigeria were investigated for fumonisin B1 (FB1) content and Fusarium verticillioides colonization. F. verticillioides DNA was quantified by species-specific real-time PCR and living propagules of the fungus were counted by agar-plating method. FB1 was detected in 55 (68.7%) of the total samples (mean: 98.5 μg/kg, range: 10 to 714 μg/kg) at 10 μg/kg detection limit. The mean amount of F. verticillioides DNA determined by real-time PCR was 49.7 μg/kg (range: 10–126.7 μg/kg), while agar plate method showed the presence of F. verticillioides in 45 samples (mean incidence: 21.0%, range: 6.7–60.0%). There was correlation ties between F. verticillioides DNA by real time PCR and fungal colonization by agar plate method (R = 0.71, p = 00001 at 95% confidence level), and means of FB1 and F. verticillioides DNA in the yellow and white maize were significantly different. Despite the high consumption of maize in Nigeria, the amount of FB1 ingested by consumers appears to be low. The estimated daily intake of fumonisins was 0.21 μg/kg body weight per day."],["dc.identifier.doi","10.2478/v10045-009-0063-8"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/10962"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/58154"],["dc.language.iso","en"],["dc.notes.intern","Merged from goescholar"],["dc.relation.issn","1899-007X"],["dc.rights","Goescholar"],["dc.rights.uri","https://goescholar.uni-goettingen.de/licenses"],["dc.title","Real-Time PCR and Agar Plating Method to Predict Fusarium Verticillioides and Fumonisin B1 Content in Nigerian Maize"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","444"],["dc.bibliographiccitation.issue","5"],["dc.bibliographiccitation.journal","Phytopathology"],["dc.bibliographiccitation.lastpage","453"],["dc.bibliographiccitation.volume","100"],["dc.contributor.author","Becher, Rayko"],["dc.contributor.author","Hettwer, Ursula"],["dc.contributor.author","Karlovsky, Petr"],["dc.contributor.author","Deising, Holger B."],["dc.contributor.author","Wirsel, Stefan G. R."],["dc.date.accessioned","2018-11-07T08:43:49Z"],["dc.date.available","2018-11-07T08:43:49Z"],["dc.date.issued","2010"],["dc.description.abstract","Azole fungicides play a prominent role for reliable plant disease management. However, quantitative azole resistance has been shown to develop in fungal pathogens, including Fusarium graminearum the causal agent of Fusarium head blight (FHB). Due to widespread application of azole fungicides, resistance may accumulate to higher degrees in fungal field populations over time. Although azole fungicides are prominent components in FHB control, little effort has been made to investigate azole resistance in F. graminearum. We allowed E graminearum strain NRRL 13383 to adapt to an azole fungicide in vitro, applying a strongly growth-reducing but sublethal dose of tebuconazole. Two morphologically distinguishable azole-resistant phenotypes were recovered that differed with regard to levels of fitness, fungicide resistance, virulence, and mycotoxin production. Isolates of the adapted \"phenotype 1\" exhibited azole-specific cross-resistance, whereas \"phenotype 2\" isolates displayed the phenomenon of multidrug resistance because the sensitivity to amine fungicides was also affected. Assessment of individual infected spikelets for mycotoxin contents by high-performance liquid chromatography mass spectrometry and for Fusarium DNA by quantitative polymerase chain reaction indicated that some of the adapted isolates produced significantly higher levels of nivalenol per fungal biomass than the NRRL 13383 strain."],["dc.identifier.doi","10.1094/PHYTO-100-5-0444"],["dc.identifier.isi","000277028600006"],["dc.identifier.pmid","20373965"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/7608"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/20063"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Phytopathological Soc"],["dc.relation.issn","0031-949X"],["dc.rights","Goescholar"],["dc.rights.uri","https://goescholar.uni-goettingen.de/licenses"],["dc.title","Adaptation of Fusarium graminearum to Tebuconazole Yielded Descendants Diverging for Levels of Fitness, Fungicide Resistance, Virulence, and Mycotoxin Production"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.issue","5"],["dc.bibliographiccitation.journal","Mycoses"],["dc.bibliographiccitation.volume","51"],["dc.contributor.author","Zuther, Katja"],["dc.contributor.author","Mayser, Peter"],["dc.contributor.author","Hettwer, Ursula"],["dc.contributor.author","Wu, W."],["dc.contributor.author","Spiteller, Peter"],["dc.contributor.author","Kindler, Bernhard L. J."],["dc.contributor.author","Karlovsky, Petr"],["dc.contributor.author","Basse, Christoph W."],["dc.contributor.author","Schirawski, Jan"],["dc.date.accessioned","2018-11-07T11:20:25Z"],["dc.date.available","2018-11-07T11:20:25Z"],["dc.date.issued","2008"],["dc.format.extent","399"],["dc.identifier.isi","000258408900062"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/55533"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Wiley-blackwell"],["dc.publisher.place","Malden"],["dc.relation.issn","0933-7407"],["dc.title","Using Ustilago maydis as a model to unravel pityriasis versicolor associated tryptophan dependent pigment biosynthesis"],["dc.type","conference_abstract"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","152"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","Molecular Microbiology"],["dc.bibliographiccitation.lastpage","172"],["dc.bibliographiccitation.volume","68"],["dc.contributor.author","Zuther, Katja"],["dc.contributor.author","Mayser, Peter"],["dc.contributor.author","Hettwer, Ursula"],["dc.contributor.author","Wu, W."],["dc.contributor.author","Spiteller, Peter"],["dc.contributor.author","Kindler, Bernhard L. J."],["dc.contributor.author","Karlovsky, Petr"],["dc.contributor.author","Basse, Christoph W."],["dc.contributor.author","Schirawski, Jan"],["dc.date.accessioned","2018-11-07T11:16:46Z"],["dc.date.available","2018-11-07T11:16:46Z"],["dc.date.issued","2008"],["dc.description.abstract","Tryptophan is a precursor for many biologically active secondary metabolites. We have investigated the origin of indole pigments first described in the pityriasis versicolor-associated fungus Malassezia furfur. Some of the identified indole pigments have properties potentially explaining characteristics of the disease. As M. furfur is not amenable to genetic manipulation, we used Ustilago maydis to investigate the pathway leading to pigment production from tryptophan. We show by high-performance liquid chromatography, mass spectrometry and nuclear magnetic resonance analysis that the compounds produced by U. maydis include those putatively involved in the etiology of pityriasis versicolor. Using a reverse genetics approach, we demonstrate that the tryptophan aminotransferase Tam1 catalyses pigment biosynthesis by conversion of tryptophan into indolepyruvate. A forward genetics approach led to the identification of mutants incapable of producing the pigments. These mutants were affected in the sir1 gene, presumably encoding a sulphite reductase. In vitro experiments with purified Tam1 showed that 2-oxo 4-methylthio butanoate serves as a substrate linking tryptophan deamination to sulphur metabolism. We provide the first direct evidence that these indole pigments form spontaneously from indolepyruvate and tryptophan without any enzymatic activity. This suggests that compounds with a proposed function in M. furfur-associated disease consist of indolepyruvate-derived spontaneously generated metabolic by-products."],["dc.identifier.doi","10.1111/j.1365-2958.2008.06144.x"],["dc.identifier.isi","000253889700014"],["dc.identifier.pmid","18312268"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/54668"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Wiley-blackwell"],["dc.relation.issn","1365-2958"],["dc.relation.issn","0950-382X"],["dc.title","The tryptophan aminotransferase Tam1 catalyses the single biosynthetic step for tryptophan-dependent pigment synthesis in Ustilago maydis"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","993"],["dc.bibliographiccitation.issue","9"],["dc.bibliographiccitation.journal","FOOD ADDITIVES AND CONTAMINANTS"],["dc.bibliographiccitation.lastpage","1000"],["dc.bibliographiccitation.volume","24"],["dc.contributor.author","Adejumo, Timothy O."],["dc.contributor.author","Hettwer, Ursula"],["dc.contributor.author","Karlovsky, Petr"],["dc.date.accessioned","2018-11-07T11:06:34Z"],["dc.date.available","2018-11-07T11:06:34Z"],["dc.date.issued","2007"],["dc.description.abstract","A survey for the natural occurrence of Fusarium mycotoxins in maize for human consumption in four south-western states of Nigeria using High Performance Liquid Chromatography coupled with Mass Spectroscopy (HPLC/ MS) showed that 93.4% of the samples were contaminated with zearalenone (ZON), alpha- and beta-zearalenols (alpha- and beta- ZOL), fumonisin B-1 (FB1) or enniatins ( ENNs). The fractions of contaminated samples were 73% for FB1 ( mean: 117 mu g kg(-1), range: 10-760 mu g kg(-1)); 57% for ZON ( mean: 49 mu g kg(-1), range: 115 - 779 mg kg(-1)) and 13% for alpha- ZOL ( mean: 63.6 mu g kg (-1), range: 32 - 181 mu g kg(-1)), while ENNs A1, B and B-1 were present in 3, 7 and 3% of the samples respectively. There was no beta- ZOL present above the quantification limits of 50 mu g kg(-1). Only the FB1 content was significantly different at the 95% confidence level among the four states. The Fusarium species most frequently isolated from maize seeds were F. verticillioides ( 70%), followed by F. sporotrichioides ( 42%), F. graminearum ( 30%), F. pallidoroseum ( 15%), F. compactum ( 12%), F. proliferatum ( 12%), F. equiseti ( 9%), F. acuminatum ( 8%) and F. subglutinans ( 4%). This is the first report of the occurrence of alpha- zearalenol and enniatins in Nigerian maize."],["dc.identifier.doi","10.1080/02652030701317285"],["dc.identifier.isi","000249129700010"],["dc.identifier.pmid","17691013"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/10954"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/52347"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Taylor & Francis Ltd"],["dc.relation.issn","0265-203X"],["dc.rights","Goescholar"],["dc.rights.uri","https://goescholar.uni-goettingen.de/licenses"],["dc.title","Survey of maize from south-western Nigeria for zearalenone, alpha- and beta-zearalenols, fumonisin B-1 and enniatins produced by Fusarium species"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dc.type.version","submitted_version"],["dspace.entity.type","Publication"]]