Newest publications
Mitochondrial genome amplification of avian haemosporidian parasites from single-infected wildlife samples using a novel nested PCR approach
(2023) Musa, Sandrine
Haemosporidian parasites that infect birds (Apicomplexa: Haemosporida) are blood parasites that require an invertebrate host (vector) and a vertebrate host for their lifecycle and cause malaria-like diseases. This group of parasites has provided valuable insights into host specificity, virulence, and parasite dispersal. Additionally, they have played a significant role in reshaping our understanding of the evolutionary history of apicomplexans. In order to accurately identify species and to address phylogenetic questions such as the timing of the haemosporidian radiation, the use of a sufficiently large genetic data set is crucial. However, acquiring this genetic data poses significant challenges. In this research, a sensitive nested PCR assay was developed. This assay allows for the easy amplification of complete mitochondrial genomes of haemosporidian parasites in birds, even during the chronic stage of infection. The effectiveness of this new nested PCR assay was evaluated using blood and tissue samples of birds with verified single parasite infections from previous studies. The approach involves amplifying four overlapping fragments of the mitochondrial genome and requires DNA extracts from single-infected samples. This method successfully amplified the complete mitochondrial genomes of 24 distinct haemosporidian parasite lineages found in various bird species. This data is invaluable for conducting phylogenetic analyses and accurately defining species. Furthermore, this study proposes the existence of at least 15 new haemosporidian parasite species based on the genetic information obtained. Data regarding pGRW04, previously categorized as Plasmodium relictum like pSGS1 and pGRW11, indicates that the pGRW04 lineage is actually a separate, hidden Plasmodium species.
How fluid pseudoplasticity and elasticity affect propeller flows in biogas fermenters
(2024) Kolano, Markus; Ohnmacht, Benjamin; Lemmer, Andreas; Kraume, Matthias
Mixing in biogas fermenters is complex due to the non‐Newtonian rheology of biogenic substrates, which exhibit both pseudoplasticity and elasticity. It is yet unclear how these non‐Newtonian properties affect propeller flows and the mixing behavior in fermenters. Therefore, propeller flows in Newtonian as well as shear‐thinning inelastic and elastic fluids are compared numerically and validated against particle image velocity (PIV) data. Elastic normal stresses lead to an increase of pumping rates in the laminar regime and a suppression of the formation of a propeller jet in the transitional regime. Thus, flow rates are severely overestimated by the inelastic, shear‐thinning model in this regime. The results indicate that elasticity is critical for an accurate modeling of flows of biogenic substrates.
First report on the emergence of Neopestalotiopsis rosae as a severe economic threat to strawberry production in Germany
(2024) Schierling, Tom E.; Voegele, Ralf T.; El-Hasan, Abbas; Gonçalves, Micael F. M.
Strawberries hold significant economic importance in both German and global agriculture. However, their yield is often adversely affected by fungal diseases. This study describes Neopestalotiopsis rosae as a newly emerging pathogen responsible for leaf blight and fruit rot in strawberries in Germany. Infected plants were observed in Hohenheim, Germany. A combination of morphological and molecular analyses, along with pathogenicity tests, confirmed the identity of N. rosae as the causal agent. Morphological examination of conidia and mycelium revealed key characteristics including the presence of versicolorous median cells, conidial appendages, black spherical conidiomata formation as well as changing colony color and fluffy texture. These properties align with the established descriptions for the species. Molecular analysis, particularly the sequencing of the internal transcribed spacer and β-tubulin regions allowed the precise identification of the pathogen. Artificial inoculation of healthy strawberry plants with conidial suspension derived from the isolated strain resulted in the development of characteristic symptoms, including necrotic leaf spots and water-soaked fruit lesions, similar to those observed on the original infected plants. To our knowledge, this study presents the first documented occurrence of N. rosae in Germany, highlighting its emergence as a significant threat to strawberry production in Europe.
Antifungal properties of bioactive compounds isolated from Fucus vesiculosus supercritical carbon dioxide extract
(2024) Tyśkiewicz, Katarzyna; Rüttler, Felix; Tyśkiewicz, Renata; Nowak, Artur; Gruba, Marcin; Wziątek, Anita; Dębczak, Agnieszka; Sandomierski, Michał; Vetter, Walter; Cacciola, Francesco
The exploration of natural antifungal substances from algal origins is significant due to the increasing resistance of pathogens to conventional antifungal agents and the growing consumer demand for natural products. This manuscript represents the inaugural investigation into the antifungal attributes of bioactive compounds extracted from Fucus vesiculosus via supercritical carbon dioxide (scCO2) extraction utilizing contemporary countercurrent chromatography (CCC). In aligning with the prospective utilization of this extract within the agricultural sector, this study also serves as the preliminary report demonstrating the capability of Fucus vesiculosus scCO2 extract to enhance the activity of plant resistance enzymes. The fractions obtained through CCC were subjected to evaluation for their efficacy in inhibiting the macrospores of Fusarium culmorum. The CCC methodology facilitated the successful separation of fatty acids (reaching up to 82.0 wt.% in a given fraction) and fucosterol (attaining up to 79.4 wt.% in another fraction). All CCC fractions at the concentration of 1.0% were found to inhibit 100% of Fusarium culmorum growth. Moreover, Fucus vesiculosus scCO2 extract was able to activate plant resistance enzymes (Catalase, Ascorbic Peroxidase, Guaiacol Peroxidase, Phenylalanine Ammonia-Lyase, and Phenylalanine Ammonia-Lyase Activity).
Hydroxylated transformation products obtained after UV irradiation of the current-use brominated flame retardants hexabromobenzene, pentabromotoluene, and pentabromoethylbenzene
(2023) Klimm, Alexandra; Vetter, Walter
Hexabromobenzene (HBB), pentabromotoluene (PBT), and pentabromoethylbenzene (PBEB) are current-use brominated flame retardants (cuBFRs) which have been repeatedly detected in environmental samples. Since information on hydroxylated transformation products (OH-TPs) was scarcely available, the three polybrominated compounds were UV irradiated for 10 min in benzotrifluoride. Fractionation on silica gel enabled the separate collection and identification of OH-TPs. For more insights, aliquots of the separated OH-TPs were UV irradiated for another 50 min (60 min total UV irradiation time). The present investigation of polar UV irradiation products of HBB, PBT, and PBEB was successful in each case. Altogether, eight bromophenols were detected in the case of HBB (three Br3-, four Br4-, and one Br5-isomer), and nine OH-TPs were observed in the case of PBT/PBEB (six Br3- and three Br4-congeners). In either case, Br➔OH exchange was more relevant than H➔OH exchange. Also, such exchange was most relevant in meta- and ortho-positions. As a further point, and in agreement with other studies, the transformation rate decreased with decreasing degree of bromination. UV irradiation of HBB additionally resulted in the formation of tri- and tetrabrominated dihydroxylated compounds (brominated diphenols) that were subsequently identified. These dihydroxylated transformation products were found to be more stable than OH-TPs.