Phaidra - University of Veterinary Medicine Vienna
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Remodeling of skeletal muscle myosin metabolic states in hibernating mammals
No full textHibernation is a period of metabolic suppression utilized by many small and large mammal species to survive during winter periods. As the underlying cellular and molecular mechanisms remain incompletely understood, our study aimed to determine whether skeletal muscle myosin and its metabolic efficiency undergo alterations during hibernation to optimize energy utilization. We isolated muscle fibers from small hibernators, Ictidomys tridecemlineatus and Eliomys quercinus and larger hibernators, Ursus arctos and Ursus americanus. We then conducted loaded Mant-ATP chase experiments alongside X-ray diffraction to measure resting myosin dynamics and its ATP demand. In parallel, we performed multiple proteomics analyses. Our results showed a preservation of myosin structure in U. arctos and U. americanus during hibernation, whilst in I. tridecemlineatus and E. quercinus, changes in myosin metabolic states during torpor unexpectedly led to higher levels in energy expenditure of type II, fast-twitch muscle fibers at ambient lab temperatures (20 °C). Upon repeating loaded Mant-ATP chase experiments at 8 °C (near the body temperature of torpid animals), we found that myosin ATP consumption in type II muscle fibers was reduced by 77-107% during torpor compared to active periods. Additionally, we observed Myh2 hyper-phosphorylation during torpor in I. tridecemilineatus, which was predicted to stabilize the myosin molecule. This may act as a potential molecular mechanism mitigating myosin-associated increases in skeletal muscle energy expenditure during periods of torpor in response to cold exposure. Altogether, we demonstrate that resting myosin is altered in hibernating mammals, contributing to significant changes to the ATP consumption of skeletal muscle. Additionally, we observe that it is further altered in response to cold exposure and highlight myosin as a potentially contributor to skeletal muscle non-shivering thermogenesis
Controlled expression of avian pre-migratory fattening influences indices of innate immunity
No full textWhile immunity is frequently dampened when birds engage in strenuous migratory flights, whether and how immunity changes during the rapid accumulation of energy stores in preparation for migration remains largely unknown. Here we induced pre-migratory fattening through controlled changes of daylight in common quails (Coturnix coturnix) and regularly assessed changes in three markers of constitutive innate immunity (leukocyte coping capacity or LCC, hemagglutination and hemolysis titres) and measures of body composition (lean and fat mass). All the three markers showed similar changes over the pre-migratory fattening process. LCC responses, hemagglutination titres, and hemolysis titres, were on average higher in the mid-fattening phase compared to the peak-fattening phase, when values were similar to those observed prior the start of pre-migratory fattening. At mid-fattening, we found that the birds that showed a larger accumulation of fat mass (as % of body mass) had lower LCC peak responses and hemolysis titres. Reversibly, at mid-fattening, we also found that the birds that kept a higher proportion of lean mass (as % of body mass) had the highest LCC peaks. Our results indicate that migratory birds undergo changes in immune indices (over 8 weeks) as they accumulate energy stores for migration and propose that this could be due to competing or trade-off processes between metabolic remodelling and innate immune system function
Ultraschallausbildung beim Pferd: Fokusgruppendiskussionen zu den Anforderungen einer Simulator-basierten Lehre
No full textUltrasound is a non-invasive, fast, and safe method for diagnosis finding. This technology continues to develop and is thus increasingly being used for numerous applications in daily equine medical practice. In the training of veterinary medical ultrasound skills, which include complex psychomotor skills, many training sessions are needed. These are at best conducted in one-to-one teaching situations. Consequently, there is a high demand for instructors and live animals for educational purposes, which means that ethical factors play a role in addition to high costs. In order to achieve a reduction of required horses and equipment, as well creating a possibility for students to repeatedly practice self-directed learning without time pressure, an innovative ultrasound learning environment for students to reduce the use of horses in veterinary teaching is being developed within the research project "Development of an Artificial Intelligence Supported Ultrasound Learning Environment for Students to Reduce the Use of Horses in Veterinary Teaching (3R\u27s - Reduce, Refine, Replace)". The first phase of the project includes focus group discussions to provide an overview of which areas such a model should cover, which advantages and disadvantages may arise from the use of simulation models for ultrasound education, and how the framework conditions for implementing a simulator in veterinary teaching should be designed. Through the results of the focus group discussions, a basic overview of the main requirements and possible applications of a simulation model should be achieved. This information will be then implemented in a first prototype. The focus group discussion showed that a simulation model for the US examination of the horse should be realistic and easy to use for the participants. Feedback from the simulator and the possibility of self-guided and time-unlimited learning were seen as particular advantages by the respondents. By implementing a model in teaching, the interviewees would like students to master the basic handling of the transducer and develop three-dimensional thinking. It is important for the interviewees to emphasize that teaching on a simulation model cannot and should not replace practicing on a live horse. Basically, transrectal gynecological US, orthopedic US of the distal limb and abdominal US in an emergency should be practiced on the simulation model, as these three areas are considered to be particularly relevant for practice. Subsequently, an US simulator can also be used for postgraduate training and further education with numerous possible applications.Diplomarbeit - Veterinärmedizinische Universität Wien - 2024Ultraschall als nicht invasive, schnelle und sichere Methode zur Diagnosestellung findet mit fortschreitender Entwicklung der Technik immer breitere Einsatzmöglichkeiten in der täglichen Praxis der Pferdemedizin. In der veterinärmedizinischen Ausbildung und Vermittlung von fundierten Ultraschallkenntnissen, die unter anderem komplexe psychomotorische Kompetenzen verlangen, werden viele Trainingseinheiten benötigt, die bestenfalls in Eins-zu- Eins Lehrsituationen abgehalten werden. In der Folge ergibt sich ein hoher Bedarf an Lehrenden und auch Übungstieren, wodurch neben den hohen Kosten auch ethische Faktoren eine Rolle spielen. Um eine Reduktion der benötigten Übungspferde sowie eine Möglichkeit für Studierende zum selbstgeleiteten und zeitlich unlimitierten Lernen zu erreichen, wird im Rahmen des Forschungsprojektes „Entwicklung einer durch künstliche Intelligenz gestützten Ultraschall-Lernumgebung für Studierende zur Reduktion des Einsatzes von Pferden in der tiermedizinischen Lehre (3R’s – Reduce, Refine, Replace)“ eine innovative Ultraschall- Lernumgebung entwickelt. In der ersten Phase des Projektes werden unter anderem Fokusgruppendiskussionen durchgeführt, die einen Überblick geben sollen, welche Bereiche ein solches Modell abdecken soll, welche Vor- und Nachteile sich durch den Einsatz von Simulationsmodellen für die Ultraschalluntersuchung ergeben und wie die Rahmenbedingungen zur Implementierung eines Simulators in der veterinärmedizinischen Lehre gestaltet sein sollen. Durch die Ergebnisse der Fokusgruppendiskussion soll ein grundlegender Überblick über die Hauptanforderungen und Einsatzmöglichkeiten eines Simulationsmodelles erreicht werden, um diese in einem ersten Prototyp umsetzen zu können. In der Fokusgruppendiskussion zeigte sich, dass ein Simulationsmodell für die USUntersuchung des Pferdes für die Teilnehmer:innen realistisch und einfach zu bedienen sein soll. Feedback durch den Simulator und die Möglichkeit auf selbstgeleitetes und zeitlich unbeschränktes Lernen sahen die Befragten besondere Vorteile. Durch die Implementierung eines Modells in der Lehre wünschen sich die Befragten, dass Studierende das grundlegende Handling des Schallkopfes beherrschen und sich ein dreidimensionales Denken einstellt. Es ist den Befragten wichtig, zu betonen, dass die Lehre am Simulationsmodell das Üben am lebenden Pferd nicht zur Gänze ersetzen kann und soll. Grundlegend sollen am Simulationsmodell der transrektale gynäkologische US, der orthopädische US der distalen Gliedmaße und der Abdomen-US im Notfall geübt werden können, da diese drei Bereiche als besonders praxisrelevant erachtet werden. In weiterer Folge kann ein US-Simulator auch zur postgradualen Fort- und Weiterbildung verwendet werden, hier sind die Anwendungsmöglichkeiten zahlreich
Etablierung der Tyrosinphorphorylierung zur Überprüfung des Kapazitationsstatus von Hundespermien
No full textDiplomarbeit - Veterinärmedizinische Universität Wien - 2024Die Kapazitation von Spermien ist ein wichtiger Reifungsprozess, welche für die Befruchtungsfähigkeit unerlässlich ist. Im Zuge der Kapazitation kommt es zu physiologischen und biochemischen Veränderungen am Spermium. Calcium und Bicarbonat strömen in die Zelle ein, Cholesterol strömt aus der Membran aus, die molekulare Zusammensetzung der Spermienmembran ändert sich und Proteine im Spermium werden phosphoryliert. Außerdem entwickeln die Spermien eine hyperaktivierte Bewegung. Zum Nachweis der Kapazitation beim Hund wird derzeit vor allem der Chlortetrazyklinassay verwendet, hierbei wird Calcium im Spermium angefärbt und charakteristische Färbemuster entstehen. Eine neuere Nachweismethode stellt die Tyrosinphosphorylierung dar, hierbei wird mittels fluoreszierender Antikörper dargestellt, wie Proteine während der Kapazitation verändert werden. Im Rahmen dieser Diplomarbeit wurden ein Vergleich dieser beiden Nachweisverfahren vorgenommen. Die spermienreiche Phase aus dem Ejakulat gesunder Rüden wurde auf 100 x 106 Spermien/mL verdünnt und Anteile davon entnommen zur Prüfung der Membranintegrität und Bestimmung der kinematischen Daten, sowie jeweils für den CTC-Assay und die Tyrosinphosphorylierung. Die jeweiligen Verfahren wurden nach einer Inkubationszeit von einer Stunde durchgeführt und anschließend die Ergebnisse miteinander verglichen. Zum Zeitpunkt der Beurteilung zeigten sich beim CTC-Assay 54,2 % ± 17,1 % der untersuchten Spermien als kapazitiert. Bei der Tyrosinphosphorylierung war ein Prozentsatz von 18,7 % ± 25,4 % der Spermien phosphoryliert (p = 0,075). Zwischen den unkapazitierten Spermien war ein signifikanter Unterschied erkennbar (p = 0,028). Im Rahmen der Beurteilung bestätigte sich die Hypothese, dass die Ergebnisse nicht direkt vergleichbar sind, da mit den verschiedenen Verfahren unterschiedliche Vorgänge in den Spermien dargestellt werden, welche zu unterschiedlichen Zeitpunkten der Kapazitation stattfinden.Diplomarbeit - Veterinärmedizinische Universität Wien - 2024Die Kapazitation von Spermien ist ein wichtiger Reifungsprozess, welche für die Befruchtungsfähigkeit unerlässlich ist. Im Zuge der Kapazitation kommt es zu physiologischen und biochemischen Veränderungen am Spermium. Calcium und Bicarbonat strömen in die Zelle ein, Cholesterol strömt aus der Membran aus, die molekulare Zusammensetzung der Spermienmembran ändert sich und Proteine im Spermium werden phosphoryliert. Außerdem entwickeln die Spermien eine hyperaktivierte Bewegung. Zum Nachweis der Kapazitation beim Hund wird derzeit vor allem der Chlortetrazyklinassay verwendet, hierbei wird Calcium im Spermium angefärbt und charakteristische Färbemuster entstehen. Eine neuere Nachweismethode stellt die Tyrosinphosphorylierung dar, hierbei wird mittels fluoreszierender Antikörper dargestellt, wie Proteine während der Kapazitation verändert werden. Im Rahmen dieser Diplomarbeit wurden ein Vergleich dieser beiden Nachweisverfahren vorgenommen. Die spermienreiche Phase aus dem Ejakulat gesunder Rüden wurde auf 100 x 106 Spermien/mL verdünnt und Anteile davon entnommen zur Prüfung der Membranintegrität und Bestimmung der kinematischen Daten, sowie jeweils für den CTC-Assay und die Tyrosinphosphorylierung. Die jeweiligen Verfahren wurden nach einer Inkubationszeit von einer Stunde durchgeführt und anschließend die Ergebnisse miteinander verglichen. Zum Zeitpunkt der Beurteilung zeigten sich beim CTC-Assay 54,2 % ± 17,1 % der untersuchten Spermien als kapazitiert. Bei der Tyrosinphosphorylierung war ein Prozentsatz von 18,7 % ± 25,4 % der Spermien phosphoryliert (p = 0,075). Zwischen den unkapazitierten Spermien war ein signifikanter Unterschied erkennbar (p = 0,028). Im Rahmen der Beurteilung bestätigte sich die Hypothese, dass die Ergebnisse nicht direkt vergleichbar sind, da mit den verschiedenen Verfahren unterschiedliche Vorgänge in den Spermien dargestellt werden, welche zu unterschiedlichen Zeitpunkten der Kapazitation stattfinden.Capacitation is an important spermatozoa maturation process and essential for fertilization. During capacitation, physiological and biochemical changes occur in the cell. Calcium and bicarbonate flow into the cell, cholesterol is transported through and out of the sperm membrane, the molecular composition of the sperm membrane changes and sperm proteins are phosphorylated. The chlortetracycline (CTC) assay is a frequently used method to detect capacitation in canine spermatozoa. Within this method, intracellular calcium binds chlortetracycline, resulting in characteristic staining patterns. Another method for determining the capacitation state of sperm is the tyrosine phoshporylation assay. This method uses fluorescent antibodies to indicate modification of location of a special membrane protein during capacitation. The aim of this study was to compare these two methods. The sperm-rich phase from the ejaculate of healthy male dogs was diluted to 100 x 106 sperm/mL and aliquots were taken for determining membrane integrity and kinematic data, as well as for the chlortetracycline assay and tyrosine phosphorylation. The different methods were performed after an incubation period of one hour, then the results were compared. At the time of assessment, the CTC assay showed 54.2 % ± 17.1 % of capacitated sperm, whereas with tyrosine phosphorylation assay, a percentage of 18.7 % ± 25.4 % of cells was phosphorylated (p = 0.075). A significant difference was seen between the uncapacitated spermatozoa (p = 0.028). During the assessment, it became apparent that the hypothesis was true and results are not directly comparable, since the different methods evaluate different processes during capacitation occuring at different time points of capacitation
One Health in retrospektiver Betrachtung der Historia animalium von Aristoteles
No full textDiplomarbeit - Veterinärmedizinische Universität Wien - 202
A poisonous cocktail: interplay of cereulide toxin and its structural isomers in emetic Bacillus cereus
No full textFood intoxications evoked by emetic Bacillus cereus strains constitute a serious threat to public health, leading to emesis and severe organ failure. The emetic peptide toxin cereulide, assembled by the non-ribosomal peptide synthetase CesNRPS, cannot be eradicated from contaminated food by usual hygienic measures due to its molecular size and structural stability. Next to cereulide, diverse chemical variants have been described recently that are produced concurrently with cereulide by CesNRPS. However, the contribution of these isocereulides to the actual toxicity of emetic B. cereus, which produces a cocktail of these toxins in a certain ratio, is still elusive. Since cereulide isoforms have already been detected in food remnants from foodborne outbreaks, we aimed to gain insights into the composition of isocereulides and their impact on the overall toxicity of emetic B. cereus. The amounts and ratios of cereulide and isocereulides were determined in B. cereus grown under standard laboratory conditions and in a contaminated sample of fried rice balls responsible for one of the most severe food outbreaks caused by emetic B. cereus in recent years. The ratios of variants were determined as robust, produced either under laboratory or natural, food-poisoning conditions. Examination of their actual toxicity in human epithelial HEp2-cells revealed that isocereulides A-N, although accounting for only 10% of the total cereulide toxins, were responsible for about 40% of the total cytotoxicity. An this despite the fact that some of the isocereulides were less cytotoxic than cereulide when tested individually for cytotoxicity. To estimate the additive, synergistic or antagonistic effects of the single variants, each cereulide variant was mixed with cereulide in a 1:9 and 1:1 binary blend, respectively, and tested on human cells. The results showed additive and synergistic impacts of single variants, highlighting the importance of including not only cereulide but also the isocereulides in routine food and clinical diagnostics to achieve a realistic toxicity evaluation of emetic B. cereus in contaminated food as well as in patient samples linked to foodborne outbreaks. Since the individual isoforms confer different cell toxicity both alone and in association with cereulide, further investigations are needed to fully understand their cocktail effect
The Relation between Milk Lactose Concentration and the Rumination, Feeding, and Locomotion Behavior of Early-Lactation Dairy Cows
No full textThis study hypothesizes that higher in-line milk lactose concentrations are indicative of enhanced dairy cow behaviors-including increased rumination, feeding, and locomotion activities-reflecting superior overall health and well-being. It posits that fluctuations in milk lactose levels have a substantial impact on the physiological and behavioral responses of dairy cows, thereby affecting their milk yields and compositions. Each cow\u27s milk lactose, fat, protein, and fat-to-protein ratio were continuously monitored using the BROLIS HerdLine in-line milk analyzer (Brolis Sensor Technology, Vilnius, Lithuania). The RumiWatch noseband sensor (RWS; ITIN + HOCH GmbH, Fütterungstechnik, Liestal, Switzerland) was employed to measure the biomarkers of the rumination, feeding, and locomotion behavior. The measurements were recorded over 5 days at the same time (during morning milking). A total of 502 cows were examined. During these 5 days, 2510 measurements were taken. Based on the lactose content in their milk, the cows were divided into two categories: the first group consisted of cows with milk lactose levels below 4.70%, while the second group included cows with milk lactose levels of 4.70% or higher. Our study showed that cows with higher milk lactose concentrations (≥4.70%) produced significantly more milk (16.14% increase) but had a lower milk protein concentration (5.05% decrease) compared to cows with lower lactose levels. These cows also exhibited changes in rumination and feeding behaviors, as recorded by the RWS: there was an increase in the mastication and rumination behaviors, evidenced by a 14.09% rise in other chews and a 13.84% increase in rumination chews, along with a 16.70% boost in bolus activity. However, there was a notable 16.18% reduction in their physical activity, as measured by the change in time spent walking
Do dogs preferentially encode the identity of the target object or the location of others\u27 actions?
No full textThe ability to make sense of and predict others\u27 actions is foundational for many socio-cognitive abilities. Dogs (Canis familiaris) constitute interesting comparative models for the study of action perception due to their marked sensitivity to human actions. We tested companion dogs (N = 21) in two screen-based eye-tracking experiments, adopting a task previously used with human infants and apes, to assess which aspects of an agent\u27s action dogs consider relevant to the agent\u27s underlying intentions. An agent was shown repeatedly acting upon the same one of two objects, positioned in the same location. We then presented the objects in swapped locations and the agent approached the objects centrally (Experiment 1) or the old object in the new location or the new object in the old location (Experiment 2). Dogs\u27 anticipatory fixations and looking times did not reflect an expectation that agents should have continued approaching the same object nor the same location as witnessed during the brief familiarization phase; this contrasts with some findings with infants and apes, but aligns with findings in younger infants before they have sufficient motor experience with the observed action. However, dogs\u27 pupil dilation and latency to make an anticipatory fixation suggested that, if anything, dogs expected the agents to keep approaching the same location rather than the same object, and their looking times showed sensitivity to the animacy of the agents. We conclude that dogs, lacking motor experience with the observed actions of grasping or kicking performed by a human or inanimate agent, might interpret such actions as directed toward a specific location rather than a specific object. Future research will need to further probe the suitability of anticipatory looking as measure of dogs\u27 socio-cognitive abilities given differences between the visual systems of dogs and primates
Vaccine Based on Recombinant Fusion Protein Combining Hepatitis B Virus PreS with SARS-CoV-2 Wild-Type- and Omicron-Derived Receptor Binding Domain Strongly Induces Omicron-Neutralizing Antibodies in a Murine Model
No full textCOVID-19, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has become a recurrent endemic disease affecting the whole world. Since November 2021, Omicron and its subvariants have dominated in the spread of the disease. In order to prevent severe courses of disease, vaccines are needed to boost and maintain antibody levels capable of neutralizing Omicron. Recently, we produced and characterized a SARS-CoV-2 vaccine based on a recombinant fusion protein consisting of hepatitis B virus (HBV)-derived PreS and two SARS-CoV-2 wild-type RBDs.To develop a PreS-RBD vaccine which induces high levels of Omicron-specific neutralizing antibodies.We designed, produced, characterized and compared strain-specific (wild-type: W-PreS-W; Omicron: O-PreS-O), bivalent (mix of W-PreS-W and O-PreS-O) and chimeric (i.e., W-PreS-O) SARS-CoV-2 protein subunit vaccines. Immunogens were characterized in vitro using protein chemical methods, mass spectrometry, and circular dichroism in combination with thermal denaturation and immunological methods. In addition, BALB/c mice were immunized with aluminum-hydroxide-adsorbed proteins and aluminum hydroxide alone (i.e., placebo) to study the specific antibody and cytokine responses, safety and Omicron neutralization.Defined and pure immunogens could be produced in significant quantities as secreted and folded proteins in mammalian cells. The antibodies induced after vaccination with different doses of strain-specific, bivalent and chimeric PreS-RBD fusion proteins reacted with wild-type and Omicron RBD in a dose-dependent manner and resulted in a mixed Th1/Th2 immune response. Interestingly, the RBD-specific IgG levels induced with the different vaccines were comparable, but the W-PreS-O-induced virus neutralization titers against Omicron (median VNT50: 5000) were seven- and twofold higher than the W-PreS-W- and O-PreS-O-specific ones, respectively, and they were six-fold higher than those of the bivalent vaccine.Among the tested immunogens, the chimeric PreS-RBD subunit vaccine, W-PreS-O, induced the highest neutralizing antibody titers against Omicron. Thus, W-PreS-O seems to be a highly promising COVID-19 vaccine candidate for further preclinical and clinical evaluation
