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JLUpub ist das institutionelle Repositorium der Justus-Liebig-Universität.
JLUpub bietet Mitgliedern und Angehörigen der Universität die Möglichkeit neben wissenschaftlichen Dokumenten auch Forschungsdaten elektronisch zu veröffentlichen und dauerhaft zugänglich zu machen. Alle Veröffentlichungen erhalten einen Digital Object Identifier (DOI) und werden über nationale und internationale Bibliothekskataloge sowie Suchmaschinen nachgewiesen und auffindbar.
Neue Veröffentlichungen:
Messung elektromagnetischer Störaussendung von elektrischen Raumfahrttriebwerken im Betrieb
(2024-08-22) Kiefer, Felix
Elektromagnetische Verträglichkeit (EMV) ist eine Anforderung für alle Geräte, die Elektrizität verwenden, und daher auch ein wichtiges Thema für Raumfahrtaktivitäten. Dies gilt auch für elektrische Triebwerke, eine beliebte Option für Satellitenantriebe. Da diese Systeme in der Regel nur im Vakuum betrieben werden können, ist die Untersuchung ihrer EMV während des Betriebs eine Herausforderung. Um diese Untersuchungen zu ermöglichen, wurden an der Justus-Liebig-Universität (JLU) in Gießen zwei Anlagen gebaut. Die eine basiert auf einer Absorberkammer (engl. SAC), die andere auf einem alternativen Ansatz, der Modenverwirbelungskammer (engl. RVC). Der Schwerpunkt liegt dabei auf der Messung von gestrahlten Emissionen (engl. RE), einer speziellen Unterkategorie der EMV. In dieser Dissertation werden der Aufbau dieser Anlagen, die ersten Ergebnisse der RE-Messungen und deren wissenschaftlicher Kontext vorgestellt. Messungen mit einem sogenannten "pulsed plasma thruster" (PPT) werden zum Vergleich der SAC- und RVC-Ansätze genutzt. Zusätzliche Untersuchungen an einem Elektronen-Zyklotronresonanz Triebwerk (engl. ECRT) zeigen, dass physikalische Prozesse im Triebwerksplasma ein breitbandiges elektromagnetisches Rauschen ausstrahlen. Effekte, die ein solches Rauschen erzeugen, wurden in anderen Veröffentlichungen identifiziert und sind hier aufgeführt, um die Beobachtungen einzuordnen. Ein langfristiges Ziel an der JLU ist es, weitere elektrische Raumfahrtantriebe zu untersuchen, um ein tieferes Verständnis der zugrunde liegenden Physik zu erlangen und die Triebwerke im Hinblick auf ihre EMV einzuordnen.
Conservation of the dehiscence zone gene regulatory network in dicots and the role of the SEEDSTICK ortholog of California poppy (Eschscholzia californica) in fruit development
(2024) Lotz, Dominik; Rössner, Le Han; Ehlers, Katrin; Kong, Doudou; Rössner, Clemens; Rupp, Oliver; Becker, Annette
Background: Fruits, with their diverse shapes, colors, and flavors, represent a fascinating aspect of plant evolution and have played a significant role in human history and nutrition. Understanding the origins and evolutionary pathways of fruits offers valuable insights into plant diversity, ecological relationships, and the development of agricultural systems. Arabidopsis thaliana (Brassicaceae, core eudicot) and Eschscholzia californica (California poppy, Papaveraceae, sister group to core eudicots) both develop dry dehiscent fruits, with two valves separating explosively from the replum-like region upon maturation. This led to the hypothesis, that homologous gene regulatory networks direct fruit development and dehiscence in both species.
Results: Transcriptome analysis of separately collected valve and replum-like tissue of California poppy yielded the SEEDSTICK (STK) ortholog as candidate for dehiscence zone regulation. Expression analysis of STK orthologs from dry dehiscing fruits of legumes (Vicia faba, Glycine max and Pisum sativum) shows their involvement in fruit development. Functional analysis using Virus-Induced Gene Silencing (VIGS) showed premature rupture of fruits and clarified the roles of EscaSTK: an evolutionary conserved role in seed filling and seed coat development, and a novel role in restricting cell divisions in the inner cell layer of the valve.
Conclusion: Our analysis shows that the gene regulatory network described in Arabidopsis is significantly different in other dicots, even if their fruits form a dehiscence zone at the valve margins. The ortholog of STK, known to be involved in ovule development and seed abscission in Arabidopsis, was recruited to a network regulating fruit wall proliferation in California poppy. There, EscaSTK allows fruit maturation without premature capsule rupture, highlighting the importance of proper endocarp development for successful seed dispersal.
Immediate dam-sourced colostrum provision reduces calf mortality - management practices and calf mortality in large dairy herds
(2024) Keller, Steffi; Donat, Karsten; Söllner-Donat, Stefanie; Wehrend, Axel; Klassen, Anne
Background: Farm-specific management practices greatly impact calf mortality rates. This cross-sectional study aimed to analyse the association between calf mortality and management practices in large dairy farms. A total of 93 dairy farms were voluntarily included in the study. All farms reared their own youngstock, and all but one kept more than 100 dairy cows. From March 2017 to March 2018, calf management practices were monitored during a farm visit, and farm managers were surveyed regarding calving procedures, neonate management, and environmental factors. Data were collated and analysed in conjunction with the 2017 calf mortality rate, as determined for each farm by using data from the German database of animal origin and movement (HI-Tier). All variables from the topics of colostrum supply, calf feeding, housing, health related information and calving preparation of the cows that resulted in P ≤ 0.1 in the analysis of variance were assumed to be associated with the calf mortality rate and were considered for a general linear mixed regression model.
Results: According to the data from the HI-Tier database of the 93 study herds from 2017, 54,474 calves were born alive and 3,790 calves died within the first six months of life. The calf mortality rate was lower on farms where calves were immediately provided with dam-sourced colostrum. Farm managers perceiving dust as the primary factor precipitating respiratory disease on the farm was positively associated with calf mortality. Regularly replacing bucket teats correlated with lower calf mortality rates compared to replacing them only upon detection of abrasion.
Conclusions: The study findings suggest that feeding calves with dam-sourced colostrum can potentially reduce overall calf mortality within the herd. This management practice holds comparable importance to ensuring successful passive transfer through timely and adequate colostrum feeding. Moreover, maintaining a low dust environment for the calves and consistently replacing bucket teats play significant roles in promoting better overall calf health.
Comparative evaluation of the modulatory role of 1,25-dihydroxy-vitamin D3 on endoplasmic reticulum stress-induced effects in 2D and 3D cultures of the intestinal porcine epithelial cell line IPEC-J2
(2024) Wen, Gaiping; Eder, Klaus; Ringseis, Robert
Background: The use of conventional two-dimensional (2D) culture of the porcine intestinal epithelial cell (IEC) line IPEC-J2 in animal nutrition research has the disadvantage that IEC function is studied under unphysiological conditions, which limits the ability of transferring knowledge to the in vivo-situation. Thus, the aim of the present study was to establish a more convincing and meaningful three-dimensional (3D) culture of IPEC-J2 cells, which allows to study cell function in a more tissue-like environment, and to compare the effect of the endoplasmic reticulum (ER) stress inducer tunicamycin (TM) on ER stress indicators and the expression of tight junction proteins (TJP), inflammatory and apoptosis-related genes and the modulatory role of 1,25-dihydroxy-vitamin D3 (1,25D3) on these parameters in 2D and 3D cultures of IPEC-J2 cells.
Results: A published protocol for 3D culture of Caco-2 cells was successfully adopted to IPEC-J2 cells as evident from fully differentiated 3D IPEC-J2 spheroids showing the characteristic spherical architecture with a single layer of IPEC-J2 cells surrounding a central lumen. Treatment of 2D IPEC-J2 cells and 3D IPEC-J2 spheroids with TM for 24 h markedly increased mRNA and/or protein levels of the ER stress target genes, heat shock protein family A (Hsp70) member 5 (HSPA5) and DNA damage inducible transcript 3 (DDIT3), whereas co-treatment with TM and 1,25D3 did not mitigate TM-induced ER stress in IPEC-J2 cells in the 2D and the 3D cell culture. In contrast, TM-induced expression of pro-inflammatory [interleukin-6 (IL6), IL8] and pro-apoptotic genes [BCL2 associated X, apoptosis regulator (BAX), caspase 3 (CASP3), CASP8] and genes encoding TJP [TJP1, claudin 1 (CLDN1), CLDN3, occludin (OCLN), cadherin 1 (CDH1), junctional adhesion molecule 1 (JAM1)] was reduced by co-treatment with TM and 1,25D3 in 3D IPEC-J2 spheroids but not in the 2D cell culture.
Conclusions: The effect of 1,25D3 in the IPEC-J2 cell culture is dependent on the culture model applied. While 1,25D3 does not inhibit TM-induced expression of genes involved in inflammation, apoptosis and TJP in conventional 2D cultures of IPEC-J2 cells, TM-induced expression of these genes is abrogated by 1,25D3 in the more meaningful 3D IPEC-J2 cell culture model.
Isolated and multiple causes of equine dystocia
(2024) Ellerbrock, Markus; Krohn, Judith; Büttner, Kathrin; Wehrend, Axel
Background: Dystocia is rare in horses, but is life-threatening for mares and foals. Therefore, veterinary research depends on up-to-date data to optimise equine dystocia management. In addition, knowledge of the prognosis of equine dystocia is necessary to advise animal owners. This retrospective study of equine dystocia aimed to enrich existing datasets with up-to-date information. For the first time, the focus was on the causes of dystocia that occurred alone or in combination. Over a period of 10 years, 72 cases of dystocia were analysed using a standardised, predetermined diagnosis code.
Results: Of the 72 cases of dystocia, an isolated cause of dystocia was identified in 37 cases (51.4%) and 35 mares showed a combination of two or more causes (48.6%). Foetal causes were significantly more frequent origin of dystocia (66/69) than maternal causes (3/66) (P < 0.0001). Incorrect posture of the foetal forelimbs and head was the most common combination at 25.7%. The most common isolated cause of dystocia was incorrect posture of the foetal forelimbs (18.9%). A foetotomy was performed in 68% of cases. A caesarean section or an extraction was performed in 13.9% of the cases. Three mares died before any obstetric care was provided. Nine mares (12.5%) were not discharged alive. 73 foals were delivered of which 55 were already dead before veterinary treatment began. In relation to the total number of births in which the foetus was alive at the start of obstetric care, the foetal mortality rate was 61.1% and 88.9% by the time the mare was discharged.
Conclusions: It has been demonstrated for the first time that multiple causes of dystocia in horses are almost as common as isolated causes of dystocia. Neonatal mortality remains high, indicating that the timely detection and treatment of dystocia has the highest priority.