Institut für Biologie

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Molting incidents of Hyalomma spp. carrying human pathogens in Germany under different weather conditions
(2024) Chitimia-Dobler, Lidia; Springer, Andrea; Lang, Daniel; Lindau, Alexander; Fachet, Katrin; Dobler, Gerhard; Nijhof, Ard M.; Strube, Christina; Mackenstedt, Ute
Background: Hyalomma marginatum and H. rufipes are two-host tick species, which are mainly distributed in southern Europe, Africa to central Asia but may also be found in Central and Northern Europe through introduction by migratory birds. Methods: Ticks were collected while feeding or crawling on animals and humans, or from the environment, in different regions in Germany, between 2019 and 2021 in a citizen science study and from 2022 to 2023 in the wake of this study. Results: From 2019 to 2023, a total of 212 Hyalomma adult ticks were detected in Germany. This included 132 H. marginatum and 43 H. rufipes ticks sent to research institutions and 37 photographic records that were only identified to genus level. The number of detected ticks varied over the years, with the highest number of 119 specimens recorded in 2019, followed by 57 in 2020. Most of the specimens were collected from horses, while some were collected from other animals, humans or found crawling on human clothes or other objects inside or outside houses. The screening of 175 specimens for Crimean-Congo hemorrhagic fever virus and of 132 specimens for Babesia/Theileria spp. by PCR gave negative results, while human-pathogenic Rickettsia were detected in 44% (77/175) of the total samples. Subsequent amplicon sequencing and phylogenetic analysis of representative samples determined the species of 41 Rickettsia aeschlimannii and one R. slovaca sequences. Conclusions: Analysis of climatic factors indicated a significantly higher probability of Hyalomma occurrence at locations with higher average spring temperature during the years 2019 and 2020 compared to randomly generated pseudo-absence locations. Dry and hot conditions probably facilitated Hyalomma nymphs’ survival and molting into adults during these yea
An enzymatic cascade enables sensitive and specific proximity labeling proteomics in challenging biological systems
(2025) Sroka, Tommy J.; Sanwald, Lea K.; Prasai, Avishek; Hoeren, Josefine; Trivigno, Valentina; Chaumet, Valerie; Krauß, Louisa M.; Weber, Damian; Yildiz, Daniela; von der Malsburg, Karina; Walentek, Peter; Haberkant, Per; Schrul, Bianca; Feistel, Kerstin; Mick, David U.
Ascorbate peroxidase (APEX) is a proximity labeling enzyme used for subcellular proteomics at high spatial and temporal resolution. However, toxicity of its substrate hydrogen peroxide and background labeling by endogenous peroxidases limit its use to in vitro studies of specific cell types. To minimize toxicity and reduce non-specific background labeling we establish a more versatile in situ APEX activation (iAPEX) workflow by combining APEX2 with a D-amino acid oxidase to locally produce hydrogen peroxide. Using iAPEX, we profile the proteomes of a cellular microdomain, the primary cilium, in cell lines not readily accessible to conventional APEX labeling and identify unknown ciliary proteins. Our study validates common ciliary proteins across two distinct cell lines, while observed differences may reflect heterogeneity in primary cilia proteomes. Furthermore, iAPEX proximity labeling is applicable to a range of cellular compartments including mitochondria and lipid droplets and can be employed in Xenopus laevis , which provides a proof-of-concept for future in vivo applications.
Divergent water balance trajectories under two dominant tree species in montane forest catchment shifting from energy- to water-limitation
(2025) Zelíková, Nikol; Toušková, Jitka; Kocum, Jiří; Vlček, Lukáš; Tesař, Miroslav; Bouda, Martin; Šípek, Václav
Vegetation interacts with both soil moisture and atmospheric conditions, contributing to water flow partitioning at the land surface. Therefore, changes in both climate and land cover with vegetation affect the availability of water resources. This study aimed to determine the differential effects of climate change on the soil water regime of two common Central European montane forest types: Norway spruce ( Picea abies L.) and European beech ( Fagus sylvatica L.). A unique dataset, including 22 years (2000–2021) of measured soil water potentials, was used with a bucket-type soil water balance model to investigate differences in evapotranspiration and groundwater recharge both between the forest types and across years. Results revealed an accelerating transition from a fully energy-limited state towards water-limitation, with evidence of strict water-limitation in recent outlier years, unprecedented in this system. While long-term column-averaged pressure heads indicated drier soil at the spruce site overall, this was driven by the wettest years in the dataset. Seasonal and interannual variability of meteorological conditions drove complex but robust differences between the flow partitioning of the two forest types, which diverged further with increasing water-limitation. Higher snow interception by spruce (27 mm per season) resulted in drier soil below the spruce canopy in the cold season. Higher transpiration by beech (100 mm per season) led to increasingly drier soils over the warm seasons causing lower ground water recharge (34 mm per season). Low summer precipitation inputs exacerbated soil drying under beech more than under to spruce. These suggest that expected trends in regional climate and forest species composition may interact to produce a disproportionate shift of recharge from the summer to the winter season.
Understanding the chemodiversity of plants: quantification, variation and ecological function
(2024) Petrén, Hampus; Anaia, Redouan Adam; Aragam, Kruthika Sen; Bräutigam, Andrea; Eckert, Silvia; Heinen, Robin; Jakobs, Ruth; Ojeda‐Prieto, Lina; Popp, Moritz; Sasidharan, Rohit; Schnitzler, Jörg‐Peter; Steppuhn, Anke; Thon, Frans M.; Unsicker, Sybille B.; van Dam, Nicole M.; Weisser, Wolfgang W.; Wittmann, Meike J.; Yepes, Sol; Ziaja, Dominik; Müller, Caroline; Junker, Robert R.
Plants produce a great number of phytochemicals serving a variety of different functions. Recently, the chemodiversity of these compounds (i.e., the diversity of compounds produced by a plant) has been suggested to be an important aspect of the plant phenotype that may shape interactions between plants, their environment, and other organisms. However, we lack an agreement on how to quantify chemodiversity, which complicates conclusions about the functional importance of it. Here, we discuss how chemodiversity (deconstructed into components of richness, evenness and disparity) may relate to different ecologically relevant aspects of the phenotype. Then, we systematically review the literature on chemodiversity to examine methodological practices, explore patterns of variability in diversity across different levels of biological organization, and investigate the functional role of this diversity in interactions between plants and other organisms. Overall, the reviewed literature suggests that high chemodiversity is often beneficial for plants, although a heterogeneity of methodological approaches partly limits what general conclusions can be drawn. Importantly, to support future research on this topic, we provide a framework with a decision tree facilitating choices on which measures of chemodiversity are best used in different contexts and outline key questions and avenues for future research. A more thorough understanding of chemodiversity will provide insights into its evolution and functional role in ecological interactions between plants and their environment.
Regulation of Klotho production by mineralocorticoid receptor signaling in renal cell lines
(2025) Kohm, Elena; Feger, Martina; Föller, Michael; Kohm, Elena; Department of Physiology, University of Hohenheim, Garbenstraße 30, 70599 Stuttgart, Germany; Feger, Martina; Department of Physiology, University of Hohenheim, Garbenstraße 30, 70599 Stuttgart, Germany; Yayama, Katsutoshi; Department of Physiology, University of Hohenheim, Garbenstraße 30, 70599 Stuttgart, Germany; Yayama, Katsutoshi
Through the mineralocorticoid receptor, aldosterone controls extracellular volume and arterial blood pressure by stimulating Na⁺ absorption and K⁺ secretion in epithelial cells of the kidney, colon, and several glands. Hyperaldosteronism promotes fibrosis and inflammation in epithelial and non-epithelial tissues, thereby favoring loss of kidney and heart function. Mineralocorticoid receptor blockade therefore gains relevance especially in renal and cardiac disease. Kidney-derived Klotho is a powerful anti-aging protein with anti-fibrosis and anti-inflammatory effects providing cardio- and nephroprotection. We wondered whether Klotho expression and production is influenced by mineralocorticoid receptor agonists and antagonists. Using four renal cell lines, Madin-Darby canine kidney (MDCK), normal rat kidney, subtype 52E (NRK-52E), human kidney 2 (HK2) cells, and primary renal proximal tubule epithelial cells (RPTECs), and the four most frequently prescribed mineralocorticoid receptor blockers, spironolactone, eplerenone, finerenone, and esaxerenone, we assessed Klotho gene expression by qRT-PCR and Klotho protein by Western blotting. Aldosterone and eplerenone did not significantly affect Klotho expression in either cell line. Spironolactone enhanced Klotho expression in MDCK and NRK-52E cells and downregulated Klotho in HK2 cells and RPTECs. Novel non-steroidal mineralocorticoid receptor antagonist finerenone downregulated Klotho expression in MDCK, NRK-52E, and low-dose finerenone in HK2 cells. To conclude, common mineralocorticoid receptor antagonists are characterized by highly diverse effects on Klotho in four renal cell lines. Further studies are needed to define the role of mineralocorticoid receptor blockade for Klotho production.
Evaluation of Plateosaurus trossingensis from the Upper Triassic (upper Norian) of Central Europe
(2024) Schaeffer, Joep; Schoch, Rainer
Plateosaurus is the fifth described dinosaur species that is still considered valid today. It is one of the best known non-sauropod sauropodomorphs and arguably the best known European dinosaur. Since its naming in 1837, partial and complete skeletons from over 250 individuals have been excavated in Germany, France and Switzerland. The majority of the specimens comes from three major localities along with several smaller sites. The largest of the three main localities is the Obere Mühle in Trossingen in Baden-Württemberg, Southwestern Germany, where over 100 individuals have been excavated. The second significant locality is the Gruhalde quarry in Frick in Aargau, Northern Switzerland, where around 80 individuals have been found. The Last locality, which was discovered the earliest, is the Baerecke-Limpricht clay-pit in Halberstadt in Saxony-Anhalt, Central Germany yielding over 40 specimens. Despite the discovery of numerous specimens over the past 190 years, significant controversy still surrounds the taxonomy of Plateosaurus. Over the past 187 years at least 30 taxa has been named within the genus of Plateosaurus or referred to it at some point. The type specimen of Plateosaurus engelhardti was deemed undiagnostic in 2019, after which it was replaced by a new type, SMNS 13200, using the name Plateosaurus trossingensis. SMNS 13200 was excavated in 1912 by Eberhard Fraas, and described by Friedrich von Huene in 1926. This was the most comprehensive description of a complete, adult specimen of Plateosaurus for 98 years. Chapter 1 of this dissertation offers a detailed redescription of this same specimen, SMNS 13200, the holotype of Plateosaurus trossingensis. I identified a unique combination of characters, making up a revised diagnosis for the species; six premaxillary teeth; nasal length greater than half the length of the skull roof; dorsal end of the lacrimal with a broad, weakly rugose, lateral sheet covering the posterodorsal corner of the antorbital fenestra; anterolateral notch in prefrontal; palatine with a ventrally located, ventral, peg-like process; the cultriform process of the parabasisphenoid is positioned ventrally to the level of the occipital condyle; posteromedially directed median process at the base of the basipterygoid processes; deep median recess on the ventral surface of the basioccipital, directly anterior to the basal tubera; anterior end of the dentary is downturned; sacrum consisting of two fused primordial vertebrae and an unfused caudosacral vertebra; anterior three caudal neural spines have an anteroposterior length greater than 40% of their height; stout metacarpal V with a convex proximal articular surface; laterally compressed, sub-oval, distal ischial expansions. An new phylogenetic analysis places Plateosaurus trossingensis within the Plateosauridae, accompanied by Sellosaurus and Unaysaurus, just outside of Massopoda. This redescription establishes an updated reference point for comparing new and existing specimens, representing a crucial first step toward resolving the taxonomic difficulties within the genusPlateosaurus. During the redescription of SMNS 13200, several pathologies in the chevrons of this specimen were observed. Palaeopathologies have been identified in nearly all groups of fossil vertebrates with dinosaurs being a significant group of which many pathologies have been documented. However, despite the discovery of over 250 specimens, no pathologies has previously been described for Plateosaurus. A more detailed investigation of several collections around the world revealed additional Plateosaurus specimens with pathologies in their chevrons. In Chapter 2, we studied two specimens in detail, SMNS 13200 and SMNS 92196, both exhibiting three consecutive pathological chevrons. In SMNS 13200 there was significant growth of periosteal new bone and SMNS 91296 showed distinct breaks. Using µCT scans, we identified potential causes for the pathologies in these specimens. First of all, in both specimens the pathologies could have been caused by a predator attack where the bite did not pierce the thick muscle covering of the tail, but left considerable damage to the periosteum in SMNS 13200 and broke three chevrons in SMNS 91296. Other possibilities would be tendon avulsions on all three chevrons of SMNS 13200, and ordinary trauma such as a fall or accidental self-trauma for SMNS 91296. From other collections we identified an additional two specimens of Plateosaurus with pathologies in the chevrons. In total 14.8% of the specimens of Plateosaurus with at least 10 preserved chevrons has some form of a pathology in the chevrons of the anterior to mid-section of the tail. This indicates pathologies in the chevrons were relatively common and could often besurvived, as long as there is no severe functional damage inflicted, the chevrons would still be able to perform their primary functions. Over the past 40 years, numerous attempts employing various methods have been made to resolve the taxonomy of Plateosaurus, yet no consensus has been reached. In chapter 3, we utilize three-dimensional geometric morphometrics to analyse 268 bones across 16 skeletal elements attributed to Plateosaurus trossingensis, collected from eight different localities. By examining the constructed morphospaces we can identify which specimens, grouped by locality, share a similar morphospace occupation, and which specimen plot in entirely different areas of the morphospace. Our results show that the specimen from the lower beds of the type locality of Plateosaurus trossingensis do not exhibit any clustering, suggesting that they likely represent a single taxon. In contrast, the specimens from Bebenhausen, Wüstenroth and Stuttgart-Erlenberg plot far away from the main cluster of specimens, indicating substantial morphological differences that may signify their classification under one or more different taxa than Plateosaurus trossingensis. The specimens from Halberstadt, Stuttgart-Degerloch, Trossingen Upper Beds, Frick and the Ruehleia bedheimensis specimens from Römhild present a more ambiguous morphospace occupation. While there are notable morphological differences between these specimens and those from the type locality, an equal number of similarities also exist. Based on these results, a detailed redescription of several specimens currently attributed to Plateosaurus trossingensis is warranted. This reassessment will involve comparing them with the holotype of Plateosaurus trossingensis to determine whether they truly belong to this species or represent a different taxon.
Smoking is associated with increased eryptosis, suicidal erythrocyte death, in a large population-based cohort
(2024) Schmitt, Marvin; Ewendt, Franz; Kluttig, Alexander; Mikolajczyk, Rafael; Kraus, F. Bernhard; Wätjen, Wim; Bürkner, Paul-Christian; Stangl, Gabriele I.; Föller, Michael
Smoking has multiple detrimental effects on health, and is a major preventable cause of premature death and chronic disease. Despite the well-described effect of inhaled substances from tobacco smoke on cell toxicity, the association between smoking and suicidal erythrocyte death, termed eryptosis, is virtually unknown. Therefore, the blood samples of 2023 participants of the German National Cohort Study (NAKO) were analyzed using flow cytometry analysis to determine eryptosis from fluorescent annexin V-FITC-binding to phosphatidylserine-exposing erythrocytes. Blood analyses were complemented by the measurement of hematologic parameters including red blood cell count, hematocrit, hemoglobin, mean corpuscular cell volume (MCV) and mean corpuscular hemoglobin (MCH). Eryptosis was higher in smokers than in non- and ex-smokers, and positively associated with the number of cigarettes smoked daily ( r = 0.08, 95% CI [0.03, 0.12]). Interestingly, despite increased eryptosis, smokers had higher red blood cell indices than non-smokers. To conclude, smokers were characterized by higher eryptosis than non-smokers, without showing any obvious detrimental effect on classic hematological parameters.
Intraspecific microbiome dynamics across the life cycle of the milkweed bug Oncopeltus fasciatus
(2026) Larner, Will; Thölke da Silva Grego, Nádia; Panfilio, Kristen A.
The microbiome is an important part of the complete nutritional and genomic profile of insects. The species-rich insect order Hemiptera (aphids, cicadas and true bugs) is highly diverse for mode of microbiome acquisition, with the conundrum that species in the seed-feeding subfamily Lygaeinae have lost obvious anatomy for housing bacteria, either in bacteriocytes or midgut crypts. Here, we characterize the microbiome of the milkweed bug Oncopeltus fasciatus as a tractable lygaeinid, using 16S rRNA gene sequencing. We assess how bacterial taxa vary between the sexes and across life history stages in a controlled environment, focusing on maternal-to-embryo transmission and distinguishing egg-stage constituents that are superficial or internal (transovarially transmitted). Among a core microbiome of 28 genera, the egg stage shows the greatest diversity, with a particular expansion of the family Comamonadaceae. We also analyse inter-individual variability in nymphs and adults and validate structured, stage-specific detection of seed material. Comparative analysis identifies Rhizobium as a notable microbiome constituent in seed-feeding Hemiptera, which we had previously shown to lack nitrogen metabolism components in the genome. Overall, we provide a nuanced assessment of bacterial abundance dynamics between individuals and across the life cycle and discuss the implications for acquisition and potential relevance as nutritional endosymbionts. This will underpin comparative investigations in seed-feeding bugs and future work in O. fasciatus on tissue-specific and diet-specific microbiome profiles, including in natural populations.
MMP21 behaves as a fluid flow transported morphogen to impart laterality during development
(2025) Ott, Tim; Brugger, Amelie; Szenker-Ravi, Emmanuelle; Kurrle, Yvonne; Aberle, Olivia; Tisler, Matthias; Blum, Martin; Whalen, Sandra; Bouvagnet, Patrice; Reversade, Bruno; Schweickert, Axel
Heterotaxy (HTX) is frequently caused by deleterious variants in the gene encoding Matrix metallopeptidase 21 (MMP21). However, the underlying pathomechanism has not been ascertained. In this study, we report on a novel HTX-associated MMP21 knockout allele in humans and investigate the peptidase’s role during laterality development using Xenopus embryos as animal model. The targeted inactivation of mmp21 in f0 mutant Xenopus successfully phenocopied the human HTX condition, yet the cilia-driven leftward fluid flow, which initiates asymmetric gene activity at the left-right organizer (LRO), was unaltered in mmp21 null frogs. Instead, our analysis of downstream events revealed that flow response, the left-sided repression of dand5, could not take place. Remarkably, gain-of-function experiments demonstrated that Mmp21 spreads over LRO cells and triggers flow response. Additionally, Mmp21 functions upstream of Cirop, another metallopeptidase, which we found specifically localized to LRO cilia. Thus, our findings suggest that Mmp21 may be the long-sought morphogen, which is actively transported by the leftward fluid flow to Cirop-laden cilia, in order to specify the left side of the embryo.
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.
High-resolution dendrometer measurements reveal different responses of Douglas-fir to extreme drought in 2018 depending on soil and rooting characteristics
(2024) Spangenberg, Göran; Zimmermann, Reiner; Küppers, Manfred; Hein, Sebastian
Introduction: Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco) is considered an important non-native substitute tree species in Europe, especially for Norway spruce ( Picea abies (L.) Karst.), mainly due to its higher drought tolerance. However, Douglas-fir has also shown increasing mortality in certain regions of the world. One of the main reasons is the increase in drought and heat periods due to climate change. There is still a need for research on the influence of important soil properties and rooting characteristics on the drought tolerance of Douglas-fir. Therefore, we analyzed the influence of soil texture, plant-available water capacity (PAWC), fine root density, and effective rooting depth on water status and thus drought stress in Douglas-fir during the extreme drought of 2018. Methods: We selected seven closely spaced sites along a soil texture gradient from sand to clay at an elevation of ca. 500 m a.s.l. in southern Germany and determined soil physical and rooting characteristics. Water status parameters and growth duration were derived from dendrometer data at five Douglas-firs per site. The influence of soil and rooting characteristics on these drought stress-related parameters was analyzed using mixed-effects models. The focus was on two summer drought periods in 2018. Results and discussion: In the initial stage of the extreme summer drought of 2018 (in June), a higher PAWC and a higher fine root density reduced drought stress. However, these influences were no longer noticeable in the later stage of drought (in August), probably due to deeper soil desiccation. In August, a higher effective rooting depth reduced drought stress. Soil texture had a significant influence, particularly on growth duration. This study provides information on site selection for Douglas-fir cultivation under the predicted increase in severe drought, showing the importance of deep and intensive rooting, and points to the need for combined above- and belowground investigations for a better understanding of the drought response patterns of tree species.
Sex pheromone of the click beetle Agriotes pilosellus (Schönherr, 1718)
(2022) Tolasch, Till; von Fragstein, Maximilian; Steidle, Johannes L. M.
Agriotes pilosellus is a fairly common click beetle species distributed in open deciduous and mixed forests throughout a large area in Europe. To identify its sex pheromone, gland extracts of female beetles were analyzed using gas chromatography-mass spectrometry (GC-MS). The only volatile compounds present in the extracts were geranyl butanoate and ( E )-8-hydroxygeranyl dibutanoate in a 1:3 ratio, identified by comparison with synthetic samples. Field experiments revealed a clear attraction of A. pilosellus - males towards traps baited with geranyl butanoate, which could be synergistically enhanced by the factor of almost ten by addition of ( E )-8-hydroxygeranyl dibutanoate. The latter compound alone did not show any attractive effect. Both compounds correspond well to the structures known from other Agriotes species and may serve as an effective monitoring tool for entomofaunistic research.
Practical preparation of unsaturated very-long-chain fatty acids (VLCFAs) and very-long-chain alkene pollinator attractants
(2024) Bohman, Björn; Bersch, Aylin J.; Flematti, Gavin R.; Schlüter, Philipp M.
To prepare very-long-chain fatty acids and alkenes (VLCFAs and VLC alkenes) that are known pollinator attractants for sexually deceptive orchids, and biosynthetic precursors thereof, we applied a methodology allowing us to prepare monounsaturated VLCFAs with chain lengths up to 28 carbons and VLC alkenes up to 31 carbons. We implemented a coupling reaction between commercially available terminal alkynes and bromoalkanoic acids to prepare VLCFAs, allowing the products to be formed in two steps. For VLC alkenes, with many alkyltriphenylphosphonium bromides commercially available, we applied a Wittig reaction approach to prepare ( Z )-configured monoenes in a single step. Using practical methods not requiring special reagents or equipment, we obtained 11 VLCFAs in > 90% isomeric purity, and 17 VLC alkenes in > 97% isomeric purity. Such general and accessible synthetic methods are essential for chemical ecology and biochemistry research to aid researchers in unambiguously identifying isolated semiochemicals and their precursors.
Mutations of PDS5 genes enhance TAD-like domain formation in Arabidopsis thaliana
(2024) Göbel, Anna-Maria; Zhou, Sida; Wang, Zhidan; Tzourtzou, Sofia; Himmelbach, Axel; Zheng, Shiwei; Pradillo, Mónica; Liu, Chang; Jiang, Hua
In eukaryotes, topologically associating domains (TADs) organize the genome into functional compartments. While TAD-like structures are common in mammals and many plants, they are challenging to detect in Arabidopsis thaliana. Here, we demonstrate that Arabidopsis PDS5 proteins play a negative role in TAD-like domain formation. Through Hi-C analysis, we show that mutations in PDS5 genes lead to the widespread emergence of enhanced TAD-like domains throughout the Arabidopsis genome, excluding pericentromeric regions. These domains exhibit increased chromatin insulation and enhanced chromatin interactions, without significant changes in gene expression or histone modifications. Our results suggest that PDS5 proteins are key regulators of genome architecture, influencing 3D chromatin organization independently of transcriptional activity. This study provides insights into the unique chromatin structure of Arabidopsis and the broader mechanisms governing plant genome folding.
The potential of farnesene isomer mixtures to support the control of aphids in the cultivation of lettuce crops
(2025) Kuhn, Denise; Bauer, Philipp; Tolasch, Till; Petschenka, Georg; Steidle, Johannes L. M.
(E)-ß-farnesene (EBF) acts as an alarm pheromone of many aphid species and is also used as an aphid repellent by plants. Upon perception of EBF, aphids exhibit avoidance behavior. They walk away, stop feeding or drop from leaves. Moreover, EBF is an attractant for natural enemies of aphids. However, EBF is not used in pest management because it is expensive in its pure form. Therefore, we assessed the effect of a less expensive farnesene isomer mixture (FIM) on Myzus persicae (Sternorrhyncha: Aphidiae) on lettuce ( Lactuca sativa var. Ulmo) in the laboratory and under field conditions. First, we tested under laboratory conditions if FIM has the same effect on M. persicae as it is described for pure EBF. The aphids were influenced by EBF. They stopped feeding, withdrew their stylets, went away from the danger zone, or developed and reproduced more slowly. Therefore, we studied the behavioral response of the aphids after FIM application and aphid reproduction under permanent exposure of FIM. Second, we tested in the field the reaction to FIM either directly applied to lettuce or released by dispensers. In the lab experiments, we found that M. persicae reacts to FIM by walking away and that reproduction tends to be reduced in the presence of FIM. In the field, we found lower numbers of aphids in the treatments with FIM. In particular, dispenser application caused higher aphid reduction compared to spray application on lettuce. In addition, more natural enemies of aphids could be found in dispenser-treated plots. Taken together, these results indicate that the use of FIM could contribute to insecticide-free aphid control in lettuce, but possibly also in other crops.
3D chromatin maps of a brown alga reveal U/V sex chromosome spatial organization
(2024) Liu, Pengfei; Vigneau, Jeromine; Craig, Rory J.; Barrera-Redondo, Josué; Avdievich, Elena; Martinho, Claudia; Borg, Michael; Haas, Fabian B.; Liu, Chang; Coelho, Susana M.
Nuclear three dimensional (3D) folding of chromatin structure has been linked to gene expression regulation and correct developmental programs, but little is known about the 3D architecture of sex chromosomes within the nucleus, and how that impacts their role in sex determination. Here, we determine the sex-specific 3D organization of the model brown alga Ectocarpus chromosomes at 2 kb resolution, by mapping long-range chromosomal interactions using Hi-C coupled with Oxford Nanopore long reads. We report that Ectocarpus interphase chromatin exhibits a non-Rabl conformation, with strong contacts among telomeres and among centromeres, which feature centromere-specific LTR retrotransposons. The Ectocarpus chromosomes do not contain large local interactive domains that resemble TADs described in animals, but their 3D genome organization is largely shaped by post-translational modifications of histone proteins. We show that the sex determining region (SDR) within the U and V chromosomes are insulated and span the centromeres and we link sex-specific chromatin dynamics and gene expression levels to the 3D chromatin structure of the U and V chromosomes. Finally, we uncover the unique conformation of a large genomic region on chromosome 6 harboring an endogenous viral element, providing insights regarding the impact of a latent giant dsDNA virus on the host genome’s 3D chromosomal folding.
SNMP1 is critical for sensitive detection of the desert locust aromatic courtship inhibition pheromone phenylacetonitrile
(2024) Lehmann, Joris; Günzel, Yannick; Khosravian, Maryam; Cassau, Sina; Kraus, Susanne; Libnow, Johanna S.; Chang, Hetan; Hansson, Bill S.; Breer, Heinz; Couzin-Fuchs, Einat; Fleischer, Joerg; Krieger, Jürgen
Background: Accurate detection of pheromones is crucial for chemical communication and reproduction in insects. In holometabolous flies and moths, the sensory neuron membrane protein 1 (SNMP1) is essential for detecting long-chain aliphatic pheromones by olfactory neurons. However, its function in hemimetabolous insects and its role for detecting pheromones of a different chemical nature remain elusive. Therefore, we investigated the relevance of SNMP1 for pheromone detection in a hemimetabolous insect pest of considerable economic importance, the desert locust Schistocerca gregaria , which moreover employs the aromatic pheromone phenylacetonitrile (PAN) to govern reproductive behaviors. Results: Employing CRISPR/Cas-mediated gene editing, a mutant locust line lacking functional SNMP1 was established. In electroantennography experiments and single sensillum recordings, we found significantly decreased electrical responses to PAN in SNMP1-deficient (SNMP1 −/− ) locusts. Moreover, calcium imaging in the antennal lobe of the brain revealed a substantially reduced activation of projection neurons in SNMP1 −/− individuals upon exposure to PAN, indicating that the diminished antennal responsiveness to PAN in mutants affects pheromone-evoked neuronal activity in the brain. Furthermore, in behavioral experiments, PAN-induced effects on pairing and mate choice were altered in SNMP1 −/− locusts. Conclusions: Our findings emphasize the importance of SNMP1 for chemical communication in a hemimetabolous insect pest. Moreover, they show that SNMP1 plays a crucial role in pheromone detection that goes beyond long-chain aliphatic substances and includes aromatic compounds controlling reproductive behaviors.
Expression of fibroblast growth factor 23 (FGF23) and αKlotho in two commercial laying hen strains fed with and without dietary mineral P supplements before and after the onset of the laying phase
(2025) Meier, Leonie; Wallauch, Nadine; Feger, Martina; Oster, Michael; Sommerfeld, Vera; Schmucker, Sonja; Wimmers, Klaus; Huber, Korinna; Stefanski, Volker; Rodehutscord, Markus; Föller, Michael
Maintenance of phosphate homeostasis is particularly critical in laying hens for bone formation and calcium mobilization. The supplementation of their feed with mineral phosphate is common although recent research questions the usual levels of supplementation. Phosphate homeostasis is classically regulated by active vitamin D (calcitriol) and parathyroid hormone, whereas fibroblast growth factor 23 (FGF23) and its co-receptor αKlotho are novel factors. FGF23 has emerged as an important disease biomarker and αKlotho as an anti-aging factor in mammals, however, little is known about their role in poultry. Here, we studied FGF23 and αKlotho expression in two commercial laying hen strains under conditions of dietary mineral phosphorus renunciation and sufficient phosphorus supply. Fifteen- and 20-week-old Lohmann Brown-Classic (LB) or LSL-Classic (LSL) hens were fed a standard maize-soybean-based diet containing 0 or 1 g/kg additional mineral phosphorus for 4 weeks. The animals were sacrificed, and gene expression studied in different organs by quantitative real-time PCR and protein expression by western blotting. Statistical correlation with further parameters of mineral metabolism was analyzed by Pearson’s correlation coefficient or Spearman’s Rho. As a result, FGF23 bone expression was significantly lower and hepatic FGF23 expression higher in 24-week-old than in 19-week-old hens. Bone, hepatic, and renal αKlotho expression was significantly higher in older than younger animals. Compared to LB hens, LSL hens exhibited higher hepatic αKlotho irrespective of diet and age. Dietary phosphorus content did not significantly affect FGF23 and αKlotho expression. Bone FGF23 expression was positively and hepatic FGF23 negatively associated with plasma phosphate concentration whereas bone FGF23 expression was negatively and hepatic FGF23 positively associated with plasma calcitriol concentration. To conclude, we uncovered a strong impact of age and strain on FGF23 and αKlotho expression in two high performance laying hen strains, effects possibly associated with initiation of the egg-laying phase. Moreover, the regulation of hepatic FGF23 expression differed from the regulation of bone FGF23 expression. Further studies are needed to elucidate the physiological relevance.
From import to establishment? Experimental evidence for seasonal outdoor survival of two Rhipicephalus species in Germany
(2025) Fachet-Lehmann, Katrin; Lindau, Alexander; Mackenstedt, Ute
The brown dog tick (Rhipicephalus sanguineus s.l.), though not endemic in Germany, is regularly introduced via travelers with dogs and imported rescue dogs. Due to its relevance in veterinary and human medicine, its potential to establish in Germany’s climate is of interest. Although previous studies confirm indoor survival and reproduction of R. sanguineus s.s. in Germany, climate change and milder winters may also allow outdoor survival. This study assessed the survival of R. sanguineus s.s. and R. innaei from February 2023 to May 2024 using laboratory-bred ticks placed at indoor and outdoor sites. Tick survival (adults, nymphs, larvae) was monitored weekly, along with temperature and humidity. Reproductive success was evaluated via oviposition and larval hatching. R. sanguineus s.s. adults survived up to 44 weeks, nymphs up to 20 weeks, and larvae up to 5 weeks. R. innaei showed shorter survival (37, 10, and 4 weeks, respectively). Successful oviposition and larval hatching occurred outdoors between May´23 and September´23 for both species. However, winter survival was not observed; all ticks died following sub-zero temperatures in December´23. Despite the inability to overwinter outdoors, both species can survive for extended periods in spring and summer and may enter homes via dogs, where conditions favor year-round survival. Their ability to transition indoors via dogs, where conditions favor year-round survival, suggests a potential for establishment in Germany through combined indoor and seasonal outdoor persistence.
Monomorium dine sp. nov. (Hymenoptera, Formicidae): a new inquiline social parasite ant species from North America
(2025) Cover, Stefan P.; Rabeling, Christian
Among the very rarest of Nearctic ants are three species of inquiline social parasites belonging to the genus Monomorium, namely Monomorium inquilinum DuBois, Monomorium pergandei (Emery), and Monomorium talbotae DuBois. All three species are known only from the type collections. Here, we describe Monomorium dine Cover & Rabeling, sp. nov., from the Navajo Nation in New Mexico, USA, a new species closely similar to the three known social parasites. Like them, M. dine appears to be a workerless inquiline that exploits a free-living Monomorium host. We also provide keys to the queens of the Nearctic Monomorium inquilines, provide the first images of these species, report new collections for Monomorium talbotae DuBois, discuss host-parasite associations, and summarize what is presently known about these mysterious social parasites.

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