Phaidra - University of Veterinary Medicine Vienna
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Bioinformatic, Enzymatic, and Structural Characterization of Trichuris suis Hexosaminidase HEX-2
No full textHexosaminidases are key enzymes in glycoconjugate metabolism and occur in all kingdoms of life. Here, we have investigated the phylogeny of the GH20 glycosyl hydrolase family in nematodes and identified a ?-hexosaminidase subclade present only in the Dorylaimia. We have expressed one of these, HEX-2 from Trichuris suis, a porcine parasite, and shown that it prefers an aryl ?-N-acetylgalactosaminide in vitro. HEX-2 has an almost neutral pH optimum and is best inhibited by GalNAc-isofagomine. Toward N-glycan substrates, it displays a preference for the removal of GalNAc residues from LacdiNAc motifs as well as the GlcNAc attached to the ?1,3-linked core mannose. Therefore, it has a broader specificity than insect fused lobe (FDL) hexosaminidases but one narrower than distant homologues from plants. Its X-ray crystal structure, the first of any subfamily 1 GH20 hexosaminidase to be determined, is closest to Streptococcus pneumoniae GH20C and the active site is predicted to be compatible with accommodating both GalNAc and GlcNAc. The new structure extends our knowledge about this large enzyme family, particularly as T. suis HEX-2 also possesses the key glutamate residue found in human hexosaminidases of either GH20 subfamily, including HEXD whose biological function remains elusive
Experimentally evolving Drosophila erecta populations may fail to establish an effective piRNA based host defense against invading P-elements
No full textTo prevent the spread of transposable elements (TEs), hosts have developed sophisticated defense mechanisms. In mammals and invertebrates, a major defense mechanism operates through PIWI-interacting RNAs (piRNAs). To investigate the establishment of the host defense, we introduced the P-element, one of the most widely studied eukaryotic transposons, into naive lines of Drosophila erecta We monitored the invasion in three replicates for more than 50 generations by sequencing the genomic DNA (using short and long reads), the small RNAs, and the transcriptome at regular intervals. A piRNA-based host defense was rapidly established in two replicates (R1, R4) but not in a third (R2), in which P-element copy numbers kept increasing for over 50 generations. We found that the ping-pong cycle could not be activated in R2, although the ping-pong cycle is fully functional against other TEs. Furthermore, R2 had both insertions in piRNA clusters and siRNAs, suggesting that neither of them is sufficient to trigger the host defense. Our work shows that control of an invading TE requires activation of the ping-pong cycle and that this activation is a stochastic event that may fail in some populations, leading to a proliferation of TEs that ultimately threaten the integrity of the host genome
Functional fixedness in chimpanzees
No full textDifferences in the tool use of non-human primates and humans are subject of ongoing debate. In humans, representations of object functions underpin efficient tool use. Yet, representations of object functions can lead to functional fixedness, which describes the fixation on a familiar tool function leading to less efficient problem solving when the problem requires using the tool for a new function. In the current study, we examined whether chimpanzees exhibit functional fixedness. After solving a problem with a tool, chimpanzees were less efficient in solving another problem which required using the same tool with a different function compared to a control group. This fixation effect was still apparent after a period of nine months and when chimpanzees had learned about the function of a tool by observation of a conspecific. These results suggest that functional fixedness in our closest living relatives likely exists and cast doubt on the notion that stable function representations are uniquely human
Management of dairy heifers: can operant conditioning be an effective and feasible tool to decrease stress and ease animals\u27 close contact and handling?
No full textBesides health monitoring, a regular check of dairy heifers\u27 growth rate is desirable, but it is rarely done because procedures that require restraint and handling can be associated with substantial stress for both animals and farmers. Inexperienced heifers, especially if they are highly responsive to humans, may find restraint and handling potentially aversive. This study investigated whether training heifers of different age and responsiveness toward humans (RTH), through operant conditioning, could reduce stress in animals, ease close contact and handling, and be feasible in terms of farmers\u27 effort. We assessed 60 Holstein heifers of 2 age classes (young, n = 29, 291 ± 39 d; old, n = 31, 346 ± 62 d) according to the avoidance distance test and classified them as confident (n = 20), neutral (n = 21), or nonconfident (n = 19). Half of the heifers of each age and RTH class were trained (n = 29), whereas the other half was not (n = 31). The trained heifers were subjected to target training for 8 sessions and positively reinforced with feed to allow being touched on the muzzle, rump, and perineum. If a heifer refused positive reinforcement, the trainer stepped back as negative reinforcement. In the last week of the experiment, the effect of training on the reaction to handling was assessed in all heifers. We measured heart rate, root mean square of successive interbeat interval differences (RMSSD), and fecal cortisol metabolites (FCMet). The presence of behavioral distress signs was recorded as well. The avoidance distance test was performed a second time 24 h after the measuring session. All of the trained heifers, regardless of RTH class, successfully accomplished the target training task in 6 sessions, each spending on average 25.3 s per session. All of the trained heifers allowed touches on the rump and perineum at the end of the fourth session. Training nonconfident heifers required more time compared with the others. Trained heifers showed higher RMSSD than nontrained heifers (14.2 vs. 16.9 ms, respectively), indicating a lower vagal tone, and thus, a slightly lower stress level than nontrained heifers. Training did not lead to differences in HR, FCMet, or presence of stress behavioral signs. Nonconfident heifers had the highest mean baseline FCMet values compared with neutral and confident heifers (38.4 vs. 30.3 vs. 29.1 ng/g, respectively). Nonconfident heifers also showed the lowest value of FCMet 12 h after the measuring session (36.7 vs. 44.6 vs. 49.7 ng/g), likely due to a decreased responsiveness of the adrenal gland to a stressor. The average avoidance distance decreased between the beginning and the end of the experiment, especially for neutral and nonconfident heifers, regardless of whether they were trained or not. These results show how using operant conditioning on some heifers not only decreased their vagal tone, but also reduced the responsiveness to humans of all the animals, trained and not trained; in the latter case, this reduction was through nonassociative learning, such as habituation
Invited Reply: Modal reasoning in non-human animals: possible ways forward
No full textNo abstract available
First step toward the numerical analysis of subchondral cystic lesions of the medial femoral condyle of adult horses
No full textDiplomarbeit - Veterinärmedizinische Universität Wien - 2024Das Hauptziel dieser Untersuchung bestand darin, eine Methode zu entwickeln, mit der Röntgenaufnahmen des medialen Femurkondylus (MFC) erwachsener Pferde mit und ohne subchondrale zystische Läsionen (SCLs) durch numerische Mustererkennung unterschieden wer den können. Zu diesem Zweck wurde eine Stichprobengruppe von 44 Röntgenaufnahmen des medialen Femurkondylus erwachsener Pferde (22 mit und 22 ohne SCL) aus der Datenbank der Veterinärmedizinischen Universität Wien (TIS) gesammelt. Für die endgültige Method e wurden die Röntgenaufnahmen rechteckig zugeschnitten, wobei die lateralen und medialen Ränder des MFC verwendet wurden, wobei die Höhe der proximalen Ausdehnung der Eminentia intercondylaris bis zum oberen Rand reichte und der untere Rand innerhalb des G elenkraums des Femorotibialgelenks lag. Diese zugeschnittenen Bilder wurden dann in ImageJ geöffnet und in Rasterquadrate mit einer Größe von 7 x 7 Pixeln unterteilt und der durchschnittliche Grauwert für diese Quadrate berechnet. Anschließend wurden diese Werte mit Microsoft Excel verarbeitet, bis ein statistisch signifikanter Unterschied zwischen den Werten der MFCs mit und ohne SCLs auftrat. Die erfolgreichsten entwickelten Methoden ergaben, dass die Standardabweichung der Differenz zwischen benachbarten QuerQuer- und Längsgitterquadraten zur Berechnung eines statistisch signifikanten Werts verwendet wurde. Die letzten beiden Methoden hatten eine Spezifität von 77,2 % und 86,3 % und beide hatten eine Sensitivität von 63,6 %. Diese Methoden wurden auch mit dre izehn MFCs mit unsicheren Diagnosen getestet, die von zwei Radiologen in der Reihenfolge „am wahrscheinlichsten“ bis „am wenigsten wahrscheinlich an einem SCL“ eingestuft wurden. Bei diesem Test stellte sich heraus, dass die entwickelten Methoden größtente ils nicht mit der Interpretation der Röntgenbilder durch die Radiologen übereinstimmten. Abschließend sind weitere Untersuchungen erforderlich, aber vorläufige Ergebnisse zeigen, dass diese Methode sinnvoll ist.Diploma thesis - University of Veterinary Medicine Vienna - 2024In this investigation, the primary goal was to develop a method through which to differentiate radiographs of the medial femoral condyle (MFC) of adult horses with and without subchondral cystic lesions (SCLs) through numerical pattern recognition. To do this a sample group of forty-four radiographs of the medial femoral condyle of adult horses were collected (twenty-two with an SCL and twenty-two without) from the University of Veterinary Medicine Vienna’s database, TIS. For the final method the radiographs were cropped rectangularly using the lateral and medial borders of the MFC, the level of the proximal extent of the eminentia intercondylaris provided to top border and the bottom border was within the joint space of the femorotibial joint. These cropped images were then opened in ImageJ and sectioned into grid squares that were 7x7 pixels large and the average grey value for those squares was calculated. Then using Microsoft Excel these values were processed until there was a statistically significant difference between the values of the MFCs with and without SCLs. The most successful methods developed found that the standard deviation of the difference between neighboring transverse and longitudinal grid squares was used to calculate a statistically significant value. The final two methods had a specificity of 77.2% and 86.3%, and both had a sensitivity of 63.6%. These methods were also tested with thirteen MFCs with uncertain diagnoses that were ranked in order from most likely to least likely to have an SCL by two radiologists. This test revealed that the methods developed mostly did not correspond to the radiologists’ interpretation of the radiographs. To conclude further investigation is needed but preliminary results show this method has merit
Feline eosinophilic sclerosing fibroplasia associated with T-/natural killer-cell lymphoma
No full textFeline eosinophilic sclerosing fibroplasia (FESF) is a proliferative, inflammatory disease of the gastrointestinal tract and other sites, uncommonly diagnosed in the cat. This entity of uncertain etiology typically presents as a progressive mass lesion, mimicking a neoplastic process. In this case series, we present 17 cases of FESF associated with intralesional lymphoma. Histologic and immunohistochemical characterization of this unique lymphoma revealed that the neoplastic lymphocytes were immunopositive for CD56 and/ or CD3, suggesting a natural killer cell, natural killer T-cell, or T-cell origin. This case series represents the first description of this lymphoma subtype, for which the term eosinophilic sclerosing lymphoma is proposed
Use and meaning of the anatomical terms plexus choroideus and tela choroidea in veterinary and human medicine
No full textThe anatomical terms Plexus chor(i)oideus (CP) and Tela chor(i)oidea (TC) are listed without explanations in the official nomenclature handbooks Terminologia Neuroanatomica and Nomina Anatomica Veterinaria. Definitions of CP and TC exhibit discrepancies in medical dictionaries and anatomy handbooks. The aim of our study was to analyse this problem in detail and to discuss a possible unified use of the terms in science and teaching. The authors conducted a systematic literature review based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses, identifying and analysing relevant scholarly articles. Additionally, comprehensive original handbooks on human and veterinary anatomy in English and other European languages were examined. The definitions of the terms CP and TC differed considerably between articles and did not match the most frequently given explanations in handbooks. In general use, it seems to have become accepted that TC represents the smooth, thin part of the roof of the third and fourth ventricles, and CP the frond- or fringe-like vascularised structures invaginated into the lateral, third and fourth ventricles. However, it is controversial which tissue layers should be included in their description. Etymologically, only the vascular network should be termed (choroid) plexus, but embryologically and functionally, epithelium, pial connective tissue, and vascular network form an inseparable entity. Similarly, the smooth part of the ventricle roof consists of a (less) vascularised pia-derived stroma and lining epithelium. Including all these layers in the definition of CP as well as TC might be advisable and also corresponds to the use of the terms in clinical context
Impact of Heat Stress on the In-Line Registered Milk Fat-to-Protein Ratio and Metabolic Profile in Dairy Cows
No full textThe aim of our study was to investigate and quantify the impact of heat stress on the milk fat-to-protein ratio (F/P) and the metabolic profile in dairy cows, utilizing in-line registration methods for accurate and real-time data collection. This study was carried out in Lithuania at coordinates 55.819156, 23.773541, from 1 June 2023 until 31 August 2023. Milk composition, including fat and protein, was measured using a BROLIS HerdLine in-line milk analyzer from Brolis Sensor Technology, Vilnius, Lithuania. During the general clinical examinations (twice per week), blood samples were collected and determined for GLU-blood glucose concentration; BHB-blood beta-hydroxybutyrate concentration; AST-aspartate transaminase activity; GGT-gamma-glutamyltransferase activity; and NEFAs-non-esterified fatty acids. The parameters based on the Temperature-Humidity Index (THI) were categorized into two groups: group 1, consisting of THI values less than 72, representing the comfort zone, and group 2, with THI values of 72 or higher, indicating a greater risk of thermal stress. Specifically, group 2 exhibited an 8.6% increase in the F/P ratio compared to group 1 (p = 0.049). Additionally, there was a 4.2% decrease in glucose levels in group 2 (p = 0.056) and a notable 5.8% decrease in albumin levels compared to group 1 (p < 0.001). We found a very weak, non-significant correlation between humidity and the milk fat-to-protein ratio (r = 0.043, p = 0.447) and a similarly negligible correlation with Beta-Hydroxybutyrate (BHB; r = 0.046, p = 0.417). We observed significant changes in milk composition, particularly an increase in the milk fat-to-protein ratio, and alterations in metabolic indicators like glucose, albumin, and liver enzymes. These changes, indicative of a negative energy balance and altered metabolic processes such as gluconeogenesis and lipolysis, correspond to previous research. The adoption of advanced tools, such as the BROLIS HerdLine analyzer, is recommended for the real-time monitoring of milk composition, which assists in the early detection of negative energy balances and metabolic issues. It is also crucial to adjust feeding practices to maintain energy balance during periods of high THI and to conduct regular health checks with a special focus on cows in early lactation
Development and In Vivo Evaluation of Small-Molecule Ligands for Positron Emission Tomography of Immune Checkpoint Modulation Targeting Programmed Cell Death 1 Ligand 1
No full textA substantial portion of patients do not benefit from programmed cell death protein 1/programmed cell death 1 ligand 1 (PD-1/PD-L1) checkpoint inhibition therapies, necessitating a deeper understanding of predictive biomarkers. Immunohistochemistry (IHC) has played a pivotal role in assessing PD-L1 expression, but small-molecule positron emission tomography (PET) tracers could offer a promising avenue to address IHC-associated limitations, i.e., invasiveness and PD-L1 expression heterogeneity. PET tracers would allow for improved quantification of PD-L1 through noninvasive whole-body imaging, thereby enhancing patient stratification. Here, a large series of PD-L1 targeting small molecules were synthesized, leveraging advantageous substructures to achieve exceptionally low nanomolar affinities. Compound 5c emerged as a promising candidate (IC50 = 10.2 nM) and underwent successful carbon-11 radiolabeling. However, a lack of in vivo tracer uptake in xenografts and notable accumulation in excretory organs was observed, underscoring the challenges encountered in small-molecule PD-L1 PET tracer development. The findings, including structure-activity relationships and in vivo biodistribution data, stand to illuminate the path forward for refining small-molecule PD-L1 PET tracers