Newest publications
An evaluation of the lineage of Brucella isolates in turkey by a whole-genome single-nucleotide polymorphism analysis
(2024) Akar, Kadir; Holzer, Katharina; Hoelzle, Ludwig E.; Yıldız Öz, Gülseren; Abdelmegid, Shaimaa; Baklan, Emin Ayhan; Eroğlu, Buket; Atıl, Eray; Moustafa, Shawky A.; Wareth, Gamal; Elkhayat, Manar; Akar, Kadir; Faculty of Veterinary Medicine, Van Yuzuncu Yıl University, 65090 Van, Turkey; Holzer, Katharina; Department of Livestock Infectiology and Environmental Hygiene, Institute of Animal Science, University of Hohenheim, 70599 Stuttgart, Germany;; Hoelzle, Ludwig E.; Department of Livestock Infectiology and Environmental Hygiene, Institute of Animal Science, University of Hohenheim, 70599 Stuttgart, Germany;; Yıldız Öz, Gülseren; NRL for Brucellosis, Pendik Veterinary Control Institute, 34890 Istanbul, Turkey; (G.Y.Ö.); (E.A.B.); (B.E.); (E.A.); Abdelmegid, Shaimaa; Faculty of Veterinary Medicine, Assiut University, Assiut 71515, Egypt;; Baklan, Emin Ayhan; NRL for Brucellosis, Pendik Veterinary Control Institute, 34890 Istanbul, Turkey; (G.Y.Ö.); (E.A.B.); (B.E.); (E.A.); Eroğlu, Buket; NRL for Brucellosis, Pendik Veterinary Control Institute, 34890 Istanbul, Turkey; (G.Y.Ö.); (E.A.B.); (B.E.); (E.A.); Atıl, Eray; NRL for Brucellosis, Pendik Veterinary Control Institute, 34890 Istanbul, Turkey; (G.Y.Ö.); (E.A.B.); (B.E.); (E.A.); Moustafa, Shawky A.; Faculty of Veterinary Medicine, Benha University, Toukh 13736, Egypt; (S.A.M.); (M.E.); Wareth, Gamal; Institute of Bacterial Infections and Zoonoses, Friedrich-Loeffler-Institute, 07743 Jena, Germany;; Elkhayat, Manar; Faculty of Veterinary Medicine, Benha University, Toukh 13736, Egypt; (S.A.M.); (M.E.); Pedersen, Karl
Brucellosis is a disease caused by the Brucella ( B. ) species. It is a zoonotic disease that affects farm animals and causes economic losses in many countries worldwide. Brucella has the ability to persist in the environment and infect the host at low doses. Thus, it is more important to trace brucellosis outbreaks, identify their sources of infection, and interrupt their transmission. Some countries already have initial data, but most of these data are based on a Multiple-Locus Variable-Number Tandem-Repeat Analysis (MLVA), which is completely unsuitable for studying the Brucella genome. Since brucellosis is an endemic disease in Turkey, this study aimed to examine the genome of Turkish Brucella isolates collected between 2018 and 2020, except for one isolate, which was from 2012. A total of 28 strains of B. melitensis ( n = 15) and B. abortus ( n = 13) were analyzed using a core-genome single-nucleotide polymorphism (cgSNP) analysis. A potential connection between the Turkish isolates and entries from Sweden, Israel, Syria, Austria, and India for B. melitensis was detected. For B. abortus , there may be potential associations with entries from China. This explains the tight ties found between Brucella strains from neighboring countries and isolates from Turkey. Therefore, it is recommended that strict measures be taken and the possible effects of uncontrolled animal introduction are emphasized.
Predictor preselection for mixed‐frequency dynamic factor models: a simulation study with an empirical application to GDP nowcasting
(2025) Franjic, Domenic; Schweikert, Karsten; Franjic, Domenic; Core Facility Hohenheim and Institute of Economics, University of Hohenheim, Stuttgart, Germany; Schweikert, Karsten; Core Facility Hohenheim and Institute of Economics, University of Hohenheim, Stuttgart, Germany
We investigate the performance of dynamic factor model nowcasting with preselected predictors in a mixed‐frequency setting. The predictors are selected via the elastic net as it is common in the targeted predictor literature. A simulation study and an application to empirical data are used to evaluate different strategies for variable selection, the influence of tuning parameters, and to determine the optimal way to handle mixed‐frequency data. We propose a novel cross‐validation approach that connects the preselection and nowcasting step. In general, we find that preselecting provides more accurate nowcasts compared with the benchmark dynamic factor model using all variables. Our newly proposed cross‐validation method outperforms the other specifications in most cases.
On the temperature stability requirements of free-running Nd:YAG lasers for atmospheric temperature profiling through the rotational Raman technique
(2024) Zenteno-Hernández, José Alex; Comerón, Adolfo; Dios, Federico; Rodríguez-Gómez, Alejandro; Muñoz-Porcar, Constantino; Sicard, Michaël; Franco, Noemi; Behrendt, Andreas; Di Girolamo, Paolo; Zenteno-Hernández, José Alex; Instituto Nacional de Astrofísica, Óptica y Electrónica (INAOE), 72840 Puebla, Mexico; Comerón, Adolfo; CommSensLab, Dept. of Signal Theory and Communications, Universitat Politècnica de Catalunya (UPC), 08034 Barcelona, Spain; Dios, Federico; CommSensLab, Dept. of Signal Theory and Communications, Universitat Politècnica de Catalunya (UPC), 08034 Barcelona, Spain; Rodríguez-Gómez, Alejandro; CommSensLab, Dept. of Signal Theory and Communications, Universitat Politècnica de Catalunya (UPC), 08034 Barcelona, Spain; Muñoz-Porcar, Constantino; CommSensLab, Dept. of Signal Theory and Communications, Universitat Politècnica de Catalunya (UPC), 08034 Barcelona, Spain; Sicard, Michaël; CommSensLab, Dept. of Signal Theory and Communications, Universitat Politècnica de Catalunya (UPC), 08034 Barcelona, Spain; Franco, Noemi; Scuola di Ingegneria, Università della Basilicata, 85100 Potenza, Italy; Behrendt, Andreas; University of Hohenheim, Institute of Physics and Meteorology, 70599 Stuttgart, Germany; Di Girolamo, Paolo; Scuola di Ingegneria, Università della Basilicata, 85100 Potenza, Italy
We assess the temperature stability requirements of unseeded Nd:YAG lasers in lidar systems for atmospheric temperature profiling through the rotational Raman technique. Taking as a reference a system using a seeded laser assumed to emit pulses of negligible spectral width and free of wavelength drifts, we estimate first the effect of the pulse spectral widening of the unseeded laser on the output of the interference filters, and then we derive the limits of the allowable wavelength drift for a given bias in the temperature measurement that would add to the noise-induced uncertainty. Finally, using spectroscopic data, we relate the allowable wavelength drift to allowable temperature variations in the YAG rod. We find that, in order to keep the bias affecting atmospheric temperature measurements smaller than 1 K, the Nd:YAG rod temperature should also be kept within a variation range of 1 K.
Extracellular vesicles isolated from dsRNA-sprayed barley plants exhibit no growth inhibition or gene silencing in Fusarium graminearum
(2022) Schlemmer, Timo; Lischka, Richard; Wegner, Linus; Ehlers, Katrin; Biedenkopf, Dagmar; Koch, Aline; Schlemmer, Timo; Institute of Phytomedicine, University of Hohenheim, Stuttgart, Germany; Lischka, Richard; Centre for BioSystems, Land Use and Nutrition, Institute of Phytopathology, Justus Liebig University, Giessen, Germany; Wegner, Linus; Intitute of Botany, Justus Liebig University, Giessen, Germany; Ehlers, Katrin; Intitute of Botany, Justus Liebig University, Giessen, Germany; Biedenkopf, Dagmar; Centre for BioSystems, Land Use and Nutrition, Institute of Phytopathology, Justus Liebig University, Giessen, Germany; Koch, Aline; Institute of Phytomedicine, University of Hohenheim, Stuttgart, Germany
Numerous reports have shown that incorporating a double-stranded RNA (dsRNA)-expressing transgene into plants or applying dsRNA by spraying it onto their leaves successfully protects them against invading pathogens exploiting the mechanism of RNA interference (RNAi). How dsRNAs or siRNAs are transferred between donor host cells and recipient fungal cells is largely unknown. It is speculated that plant extracellular vesicles (EVs) function as RNA shuttles between plants and their pathogens. Recently, we found that EVs isolated from host-induced gene silencing (HIGS) or spray-induced gene silencing (SIGS) plants contained dsRNA-derived siRNAs. In this study, we evaluated whether isolated EVs from dsRNA-sprayed barley ( Hordeum vulgare ) plants affected the growth of the phytopathogenic ascomycete Fusarium graminearum . Encouraged by our previous finding that dropping barley-derived EVs on F. graminearum cultures caused fungal stress phenotypes, we conducted an in vitro growth experiment in microtiter plates where we co-cultivated F. graminearum with plant EVs isolated from dsRNA-sprayed barley leaves. We observed that co-cultivation of F. graminearum macroconidia with barley EVs did not affect fungal growth. Furthermore, plant EVs containing SIGS-derived siRNA appeared not to affect F. graminearum growth and showed no gene silencing activity on F. graminearum CYP51 genes. Based on our findings, we concluded that either the amount of SIGS-derived siRNA was insufficient to induce target gene silencing in F. graminearum, indicating that the role of EVs in SIGS is minor, or that F. graminearum uptake of plant EVs from liquid cultures was inefficient or impossible.
Soil drought sets site specific limits to stem radial growth and sap flow of Douglas-fir across Germany
(2024) Niessner, Armin; Ehekircher, Stefan; Zimmermann, Reiner; Horna, Viviana; Reichle, Daniel; Land, Alexander; Spangenberg, Göran; Hein, Sebastian; Niessner, Armin; Department of Silviculture, University of Applied Forest Sciences, Rottenburg am Neckar, Germany; Ehekircher, Stefan; Department of Silviculture, University of Applied Forest Sciences, Rottenburg am Neckar, Germany; Zimmermann, Reiner; Ecological Botanical Gardens ÖBG, University of Bayreuth, Bayreuth, Germany; Horna, Viviana; Department of Biogeochemical Processes, Max Planck Institute for Biogeochemistry, Jena, Germany; Reichle, Daniel; Institute of Biology, University of Hohenheim, Stuttgart, Germany; Land, Alexander; Department of Silviculture, University of Applied Forest Sciences, Rottenburg am Neckar, Germany; Spangenberg, Göran; Department of Silviculture, University of Applied Forest Sciences, Rottenburg am Neckar, Germany; Hein, Sebastian; Department of Silviculture, University of Applied Forest Sciences, Rottenburg am Neckar, Germany
Introduction: Soil drought during summer in Central Europe has become more frequent and severe over the last decades. European forests are suffering increasing damage, particularly Norway spruce. Douglas-fir ( Pseudotsuga menziesii (Mirbel) Franco), a non-native tree species, is considered as a promising alternative to build drought-resilient forests. The main goal of this study was to investigate the intraannual radial stem growth and sap flow performance of Douglas-fir along a precipitation gradient across Germany under severe drought.
Material and methods: Sap flow and stem radial changes of up to ten trees each at four sites with different precipitation regimes were measured in combination with volumetric soil water content during the growing season of 2022. Measurements of stem radial changes were used to calculate the trees’ stem water deficit, a proxy for tree water status and drought stress.
Results: The severe summer drought of 2022 led to an early growth cessation and a significant reduction in daily sap flow at all four sites monitored. We could identify a site-specific threshold in soil water availability ranging between 21.7 and 29.6% of relative extractable water (REW) under which stem water reserves cannot be replenished and thereby inhibiting radial growth. We could also demonstrate that at this threshold, sap flow is heavily reduced to between 43.5 and 53.3%, and for a REW below 50%, sap flow linearly decreases by 1.1–2.0% per 1% reduction in REW. This reduction tends to follow the humidity gradient, being more pronounced at the most oceanic characterized site and suggesting an adaptation to site conditions. Even though Douglas-fir is considered to be more drought stress resistant than Norway spruce, growth and sap flow are greatly reduced by severe summer drought, which became more frequent in recent years and their frequency and intensity is likely to increase.
Conclusions: Our results suggest that timber production of Douglas-fir in Central Europe will decline considerably under projected climate change, and thus pointing to site specific growth constraints for a so far promising non-native tree species in Europe.