Stress steroid levels and the short-term impact of routine dehorning in female southern white rhinoceroses (Ceratotherium simum simum)

Rhinoceros populations in Africa are under severe threat as a result of surging poaching rates and risk-mitigation strategies are continuously adapted in an attempt to ensure the survival of the species. This study compared faecal glucocorticoid metabolite (fGCM) levels of two age classes of limited free-ranging female white rhinos with fGCM levels of adult free-ranging female white rhinos. Subsequently, fGCM alterations in the limited free-ranging animals were monitored following routine dehorning as a measure of the animals’ short-term physiological stress response. Baseline fGCM levels differed significantly between tested groups, with both free-ranging and limited free-ranging adult animals showing significantly higher fGCM levels compared with limited free-ranging juvenile females. In contrast, baseline fGCM levels did not differ significantly between limited free-ranging and free-ranging adult individuals. Routine dehorning procedures resulted in a short-term stress response expressed by a significant increase in fGCM levels 48 h post-dehorning, with stress steroid levels returning to pre-dehorning concentrations 72 h after the procedure.http://www.nisc.co.za/products/59/journals/african-zoology2017-12-31hb2017Anatomy and Physiolog

Profiling patterns of fecal 20-oxopregnane concentrations during ovarian cycles in free-ranging southern white rhinoceros (Ceratotherium simum simum)

Unlike their wild counterparts, many white rhinoceros females in captivity fail to reproduce successfully such that current captive populations are not self-sustaining. The causes of the problem are poorly understood. Variation in cycle length and long periods of acyclicity are characteristics of the majority of these non-reproducing females in captivity but it is unknown whether these characteristics are a feature of reproductively successful free-ranging females. This study therefore aimed to monitor cyclic activity in a wild population of southern white rhinoceros at Lapalala Wilderness, South Africa, by measuring the concentrations of immunoreactive fecal progestagen metabolites (fPM). Five adult females were tracked twice per week for 20 months and if located a fresh fecal sample was collected. Reproductive events and group structural dynamics were also recorded and subsequently correlated with the fPM data. The baseline concentration of fPM was 0.69 ± 0.20 μg/g DW while concentrations during pregnancy were 30- to 400- fold higher. The females exhibited estrous cycle lengths of 30.6 ± 7.7 days and, based on fPM data, gestation length in one female was 502 ± 3 days. Year-round monitoring showed no clear evidence of seasonality in ovarian activity. During cyclic luteal activity females were often seen in the presence of a dominant bull. One female stopped cycling after removal of the local dominant bull and luteal activity only returned after a new bull was introduced. This suggests that white rhinoceros females in the wild might need external stimuli from a male to ovulate. These findings indicate that the irregular cyclicity reported for white rhinoceros housed in zoos and animal parks may result from conditions in captivity and account for reduced fertility.The University of Western Australia, the Mammal Research Institute and Endocrine Research Laboratory, University of Pretoria, the Institute for Breeding Rare and Endangered African Mammals, the AAZK‘s Bowling For Rhinos, and the SAVE African Rhino Foundation.http://www.elsevier.com/locate/anireprosci2016-10-31hb201

Patterns of faecal glucocorticoid metabolite levels in captive roan antelope (Hippotragus equinus) in relation to reproductive status and season

DATA BASE : The data generated and subsequently analysed during this study are available on the repository of the University of Pretoria. The digital object identifier assigned to the data is https://doi.org/10.25403/UPresearchdata.14073662.Populations of roan antelope (Hippotragus equinus) in southern Africa have experienced a drastic decline over the past few decades and this situation has led to the development of intensive breeding programmes to support conservation efforts. However, little is known about related welfare aspects, including stress-related physiological biomarkers. The present study set out to establish a non-invasive method to monitor faecal glucocorticoid metabolite (fGCM) concentrations as a measure of stress and determine fGCM concentrations in relation to male reproductive activity and female reproductive status in the roan antelope. An adrenocorticotrophic hormone challenge was performed using two adult roan antelope (one male and one female) at Lapalala Wilderness Nature Reserve, South Africa, to determine the suitability of five enzyme immunoassays (EIA) for monitoring adrenocortical function in roan antelope. An 11-oxoaetiocholanolone I EIA detecting 11,17 dioxoandrostanes performed best showing 17–20 folds increases in fGCM concentrations after 12 h-17 h post-injection. The identified EIA was then used to monitor fGCM concentrations during active and non-active reproductive periods in males (n = 3), and during periods of cyclicity, gestation, and postpartum in females (n = 10). Males showed an overall 80% increase in fGCM concentrations when reproductively active and females showed a progressively significant increase in fGCM levels throughout pregnancy, with overall fGCM concentrations being 1.5 to 2.6-fold higher than the respective fGCM concentrations during periods of postpartum and cyclicity, respectively. Furthermore, fGCM concentrations remained above baseline for up to 21 days post-partum. A correlation between ecological parameters (rainfall and temperature) and fGCM concentrations revealed elevated fGCM concentrations during the dry season for males, but not females. The non-invasive method validated in this study provides a valuable tool to quantify stress-related biomarkers in roan antelope, and findings can be used to support management decisions in conservation breeding facilities.The National Research Foundation through the SARChI Chair for Mammal Behavioural Ecology and Physiology.https://www.elsevier.com/locate/ygcenhj2023Mammal Research InstituteZoology and Entomolog

Faecal progestagen profiles in wild southern white rhinoceros (Ceratotherium simum simum)

Knowledge of the reproductive biology of wild animals can provide valuable information for the development of appropriate in situ and ex situ management plans. The present study aimed to establish a non-invasive protocol for monitoring faecal progestagen metabolite (FPM) patterns in wild female southern white rhinoceroses (Ceratotherium simum simum). Six adult females at Lapalala Wilderness, South Africa, were tracked and accurately identified at least once every week. Three animals gave birth during the study period. Fresh faecal samples were collected for 12 months and stored frozen at –20°C until analysis with an enzyme immunoassay utilizing an antiserum raised against 5 -pregnan-3 -ol-20-one which cross-reacts with a number of progestagens. Mean FPM concentrations were 35 to 64-fold higher during pregnancy (55–145 days before parturition) compared to postpartum (120–140 days after parturition) (P < 0.001). Also, the non-pregnant animals had mean FPM concentrations significantly higher than postpartum values (P = 0.006). Our results show that non-invasive FPM measurements provide information on the pregnancy status of wild female white rhinoceroses, and may be used for the detection of pregnancy in free-living individuals, without the necessity of immobilization and/or relocation of the animal. This information has potential value for optimizing breeding management of wild and captive populations.We wish to thank the Institute for Breeding Rare and Endangered African Mammals (IBREAM) for making this research possible.We are indebted to the following students from the faculty of Veterinary Medicine at Utrecht University for their contribution in collecting faecal samples: Yvette Charbon, Belinda Bitter, Meike Meijers and Julie Swinkels. We are especially thankful to Thomas Litshani, whose exceptional rhinoceros knowledge and tracking skills greatly contributed to the number of samples collected.We are most grateful to the management of the Lapalala Wilderness reserve: Duncan Parker, Mike Gregor, Anton Walker, Roger Collinson and Anthony and Erin Roberts for permission to conduct research in the reserve as well as for their help and support. We also thank John Hanks and Henk Bertschinger for their encouragement and helpful advice, and Stefanie Ganswindt for expert help in laboratory techniques.http://africanzoology.journals.ac.za/am2013ab201

Comparative Studies in the A30P and A53T α-Synuclein C. elegans Strains to Investigate the Molecular Origins of Parkinson's Disease.

The aggregation of α-synuclein is a hallmark of Parkinson's disease (PD) and a variety of related neurological disorders. A number of mutations in this protein, including A30P and A53T, are associated with familial forms of the disease. Patients carrying the A30P mutation typically exhibit a similar age of onset and symptoms as sporadic PD, while those carrying the A53T mutation generally have an earlier age of onset and an accelerated progression. We report two C. elegans models of PD (PDA30P and PDA53T), which express these mutational variants in the muscle cells, and probed their behavior relative to animals expressing the wild-type protein (PDWT). PDA30P worms showed a reduced speed of movement and an increased paralysis rate, control worms, but no change in the frequency of body bends. By contrast, in PDA53T worms both speed and frequency of body bends were significantly decreased, and paralysis rate was increased. α-Synuclein was also observed to be less well localized into aggregates in PDA30P worms compared to PDA53T and PDWT worms, and amyloid-like features were evident later in the life of the animals, despite comparable levels of expression of α-synuclein. Furthermore, squalamine, a natural product currently in clinical trials for treating symptomatic aspects of PD, was found to reduce significantly the aggregation of α-synuclein and its associated toxicity in PDA53T and PDWT worms, but had less marked effects in PDA30P. In addition, using an antibody that targets the N-terminal region of α-synuclein, we observed a suppression of toxicity in PDA30P, PDA53T and PDWT worms. These results illustrate the use of these two C. elegans models in fundamental and applied PD research

Comparative Studies in the A30P and A53T α-Synuclein C. elegans Strains to Investigate the Molecular Origins of Parkinson's Disease

The aggregation of α-synuclein is a hallmark of Parkinson's disease (PD) and a variety of related neurological disorders. A number of mutations in this protein, including A30P and A53T, are associated with familial forms of the disease. Patients carrying the A30P mutation typically exhibit a similar age of onset and symptoms as sporadic PD, while those carrying the A53T mutation generally have an earlier age of onset and an accelerated progression. We report two C. elegans models of PD (PDA30P and PDA53T), which express these mutational variants in the muscle cells, and probed their behavior relative to animals expressing the wild-type protein (PDWT). PDA30P worms showed a reduced speed of movement and an increased paralysis rate, control worms, but no change in the frequency of body bends. By contrast, in PDA53T worms both speed and frequency of body bends were significantly decreased, and paralysis rate was increased. α-Synuclein was also observed to be less well localized into aggregates in PDA30P worms compared to PDA53T and PDWT worms, and amyloid-like features were evident later in the life of the animals, despite comparable levels of expression of α-synuclein. Furthermore, squalamine, a natural product currently in clinical trials for treating symptomatic aspects of PD, was found to reduce significantly the aggregation of α-synuclein and its associated toxicity in PDA53T and PDWT worms, but had less marked effects in PDA30P. In addition, using an antibody that targets the N-terminal region of α-synuclein, we observed a suppression of toxicity in PDA30P, PDA53T and PDWT worms. These results illustrate the use of these two C. elegans models in fundamental and applied PD research

Genetic modifiers of aging and age-related proteotoxicity

Plakkerige ziekte-eiwitten lijken een belangrijke rol te spelen bij het verdwijnen van hersencellen, wat kenmerkend is voor neurodegeneratieve ziekten zoals Alzheimer, Parkinson en Huntington. In de hersenen van patiënten worden namelijk ophopingen van deze eiwitten gevonden die er normaal niet zitten. Annemieke van der Goot onderzocht hoe de ziekte-eiwitten precies schade veroorzaken in cellen, hoe ze ophopingen vormen en hoe cellen daarop reageren. Van der Goot maakte voor haar onderzoek gebruik van de rondworm C. elegans, een modelorganisme voor genetisch onderzoek. Ze ontdekte dat het uitschakelen van twee genen (tdo-2 en moag-4) bij de wormen leidt tot minder schade door het opstapelen van verschillende ziekte-eiwitten. Deze twee genen sturen de productie van respectievelijk de eiwitten TDO-2 en MOAG-4 aan. Dat eerste eiwit is belangrijk voor het afbreken van het aminozuur tryptofaan, dat een bouwsteen is voor stoffen die onder andere invloed hebben op stemming, zelfvertrouwen en slaap. Het tweede eiwit, zo concludeert Van der Goot op basis van haar onderzoek, kan de vorming van eiwitstapeling bevorderen, waarschijnlijk via directe interactie met de ziekte-eiwitten. De identificatie van beide genen biedt volgens de promovenda niet alleen een beter inzicht in de manier waarop cellen en organismen omgaan met eiwitschade, maar vormt ook het startpunt voor vervolgonderzoek om neurodegeneratieve ziekten te behandelen of uit te stellen

Tryptophan metabolism:entering the field of aging and age-related pathologies

<p>Aging is an important risk factor for many debilitating diseases, including cancer and neurodegeneration. In model organisms, interfering with metabolic signaling pathways, including the insulin/insulin-like growth factor (IGF) 1 (IIS) and TOR pathways, can protect against age-related pathologies and increase lifespan. Recent studies in multiple organisms have implicated tryptophan metabolism as a powerful regulator of age-related diseases and lifespan. Its high conservation throughout evolution has enabled studies that begin to dissect the contribution of individual enzymes and metabolites. Here, we focus on the emerging view of tryptophan metabolism as a pathway that integrates environmental and metabolic signals to regulate animal biology and health.</p>