189 research outputs found
Assessing the social cohesion of a translocated pride of white lions integrated with wild tawny lions in South Africa, using social network analysis
In South Africa, lions are protected in national parks and smaller fenced reserves. Translocating lions between fenced reserves, whilst necessary to maintain genetic diversity, is disruptive and can impact survivorship and pride cohesion. Critical to translocation success is pride cohesion. White lions are a natural colour variant occurring in the Greater Kruger Park Region, where anthropogenic threats eliminated this population until reintroduction in 2006. Through social network analysis (SNA), the sociality of a released pride of captive-origin white and wild tawny lions was compared to two captive-origin and wild prides of tawny lions. Social interactions and pride dynamics were recorded for each pride. For all prides, cubs and subadults were central to the play network, while adults received the most social interactions. White and wild tawny adult males initiated more social interactions than captive-origin tawny males, whilst a keystone adult female was identified in each pride. For the constructed pride, social interactions were more evenly distributed, suggesting a high level of connectedness and cohesion. This is the first study to demonstrate that captive-origin white and wild tawny lions can form a socially functional pride, suggesting that white lions would survive in the wild in the absence of anthropogenic threats
Home range and movement patterns of reintroduced white lions (Panthera leo melanochaita) in the Kruger to Canyons Biosphere Reserve, South Africa
White lions are a colour variant of the African lion Panthera leo melanochaita and disappeared from the wild due to anthropogenic factors until their reintroduction to the Greater Kruger Park Region of South Africa in 2006. Natural home range behaviour is an index of reintroduction success. Therefore, the home range and movement of a pride of reintroduced white lions and a constructed pride consisting of reintroduced white lions and translocated wild tawny lionesses in small, fenced reserves was assessed. GPS data from collared adults were collected for the white lion pride between 2010â2011 and 2018â2020 for the constructed pride. Home ranges were estimated using kernel density estimation and minimum convex polygon, with minimum daily distance tested for differences between sex, season, and pride. Home ranges were small and average daily movements restricted for both prides (white lion pride: 5.41 km2 and 10.44 ± 4.82 km; constructed pride: 5.50 km2, 11.37 ± 4.72 km) due to the small reserve size of 7 km2. There was no difference between prides for annual and seasonal home range size, male and female home ranges, minimum daily distance travelled, or habitat selection. White lions from both prides established territories and displayed natural home ranging behaviour, suggesting that their reintroduction was successful, in the absence of anthropogenic threats
Phylogeographic Patterns in Africa and High Resolution Delineation of Genetic Clades in the Lion (Panthera leo)
Comparative phylogeography of African savannah mammals shows a congruent pattern in which populations in West/Central Africa are distinct from populations in East/Southern Africa. However, for the lion, all African populations are currently classified as a single subspecies (Panthera leo leo), while the only remaining population in Asia is considered to be distinct (Panthera leo persica). This distinction is disputed both by morphological and genetic data. In this study we introduce the lion as a model for African phylogeography. Analyses of mtDNA sequences reveal six supported clades and a strongly supported ancestral dichotomy with northern populations (West Africa, Central Africa, North Africa/Asia) on one branch, and southern populations (North East Africa, East/Southern Africa and South West Africa) on the other. We review taxonomies and phylogenies of other large savannah mammals, illustrating that similar clades are found in other species. The described phylogeographic pattern is considered in relation to large scale environmental changes in Africa over the past 300,000 years, attributable to climate. Refugial areas, predicted by climate envelope models, further confirm the observed pattern. We support the revision of current lion taxonomy, as recognition of a northern and a southern subspecies is more parsimonious with the evolutionary history of the lion.Netherlands Organization for Scientific Research (NWO) (project no. 820.01.002)
Threat of a lion population extinction in Waza National Park, North Cameroon.
Conservation Biology - ol
Social Structure of Lions (Panthera leo) Is Affected by Management in Pendjari Biosphere Reserve, Benin
Lion populations have undergone a severe decline in West Africa. As baseline for conservation management, we assessed the group structure of lions in the Pendjari Biosphere Reserve in Benin. This reserve, composed of one National Park and two Hunting Zones, is part of the WAP transboundary complex of protected areas. Overall mean group size was 2.661.7 individuals (n = 296), it was significantly higher in the National Park (2.761.7, n = 168) than in the Hunting Zones (2.261.5, n = 128). Overall adult sex ratio was even, but significantly biased towards females (0.67) in the National Park and towards males (1.67) in the Hunting Zones. Our results suggest that the Pendjari lion population is affected by perturbations, such as trophy hunting.Conservation Biolog
Divergent trends of large carnivore populations within the Bénoué Complex, North Cameroon, shown by long-term fine-scale monitoring
Large carnivore populations have suffered declines worldwide. For the African continent, these have been particularlystrong in West and Central Africa. The Bénoué Complex in North Cameroon, located in Central Africa, is a keylandscape for their conservation. We determined spatiotemporal trends in lion (Panthera leo), leopard (Panthera pardus)and spotted hyaena (Crocuta crocuta) abundance, using repeated spoor counts on transects from 2007 to 2015. Resultsof the temporal analysis indicate that lion and spotted hyaena abundance reduced over time across the complex, whereasleopards only declined in the last 2 years and primarily in the Faro Block. From the spatial analysis, it became clearspoor abundances differ between areas within the Bénoué Complex and between management types: Spoor densitieswere especially higher in Bouba Ndjida National Park and the hunting zones around Faro. This effect is most probablyrelated to a more effective management strategy in these areas. Our fine-scale long-term monitoring technique provides alow-cost, easy to implement, multi-scale and effective tool for the identification of both regional and range-widecarnivore conservation hotspots.Environmental Biolog
IGF-1 Counteracts TGF-ÎČ-Mediated Enhancement of Fibronectin for in Vitro Human Lens Epithelial Cells
PURPOSE: To determine whether insulin-like growth factor (IGF-1) affects transforming growth factor (TGF-beta)- mediated fibronectin accumulation in human lens epithelial cell line (HLE B-3) cells.
MATERIALS AND METHODS: HLE B-3 cells were incubated for 24 hours with TGF-beta (10 ng/ mL), IGF-1 (10 ng/mL), or both. Expression of the fibronectin gene was determined using a real-time reverse transcriptase-polymerase chain reaction (RT-PCR). Fibronectin levels were examined using western blot analysis and immunofluorescence staining.
RESULTS: Expression of the fibronectin gene was not different between the TGF-beta/IGF-1 treated group and the TGF-beta treated group (p= 0.116). However, western blot analysis demonstrated decreased fibronectin levels in human lens epithelial cells treated with TGF-beta and IGF-1 compared to those treated with TGF-beta only (p < 0.01). Immunofluorescence staining disclosed inhibition of TGF-beta-induced fibronectin in the presence of IGF-1.
CONCLUSION: This study suggests that IGF-1 counteracts TGF-beta-mediated fibronectin accumulation in human lens epithelial cells.ope
Factors associated with co-occurrence of large carnivores in a human-dominated landscape
We investigated the factors facilitating co-occurrence of two large carnivores, tigers (Panthera tigris) and common leopards (Panthera pardus), within a human-dominated landscape. We estimated their density and population size using camera-trap photographs and examined spatial segregation of habitats, temporal activity pattern, and diets in Chitwan National Park, Nepal. A Bayesian spatially-explicit capture-recapture model estimated densities of 3.2â4.6 (3.94 ± 0.37) tigers and 2.6â4.1 (3.31 ± 0.4) leopards per 100 km2 with abundance of 70â102 tigers and 66â105 leopards. Tigers occupied the prime habitats (grasslands and riverine forests) in alluvial floodplains of the Park whereas leopards appeared in Sal forests and marginal areas where livestock are present. Both tigers and leopards showed crepuscular activity patterns with a high overlap but tigers were less active during the day compared to leopards. Leopardsâ activity in the day increased in the presence of tigers. Tiger and leopard diet overlapped considerably (90%). Compared to leopards, tigers consumed a higher proportion of the large prey and a smaller proportion of livestock. Our study demonstrates that sympatric large carnivores can coexist in high densities in prey-rich areas that contain a mosaics of habitats. To increase the resilience and size of the Chitwan carnivore population, strategies are needed to increase prey biomass and prevent livestock depredation in adjacent forests. Long-term monitoring is also required to obtain a detailed understanding of the interaction between the large carnivores and their effects on local communities living in forest fringes within the landscape.Global Challenges (FSW
Whole genome sequencing and the application of a SNP panel reveal primary evolutionary lineages and genomic variation in the lion (Panthera leo)
Background Previous phylogeographic studies of the lion (Panthera leo) have improved our insight into the distribution of genetic variation, as well as a revised taxonomy which now recognizes a northern (Panthera leo leo) and a southern (Panthera leo melanochaita) subspecies. However, existing whole range phylogeographic studies on lions either consist of very limited numbers of samples, or are focused on mitochondrial DNA and/or a limited set of microsatellites. The geographic extent of genetic lineages and their phylogenetic relationships remain uncertain, clouded by massive sampling gaps, sex-biased dispersal and incomplete lineage sorting. Results In this study we present results of low depth whole genome sequencing and subsequent variant calling in ten lions sampled throughout the geographic range, resulting in the discovery of >150,000 Single Nucleotide Polymorphisms (SNPs). Phylogenetic analyses revealed the same basal split between northern and southern populations, as well as four population clusters on a more local scale. Further, we designed a SNP panel, including 125 autosomal and 14 mitochondrial SNPs, which was tested on >200 lions from across their range. Results allow us to assign individuals to one of these four major clades (West & Central Africa, India, East Africa, or Southern Africa) and delineate these clades in more detail. Conclusions The results presented here, particularly the validated SNP panel, have important applications, not only for studying populations on a local geographic scale, but also for tracing samples of unknown origin for forensic purposes, and for guiding conservation management of ex situ populations. Thus, these genomic resources not only contribute to our understanding of the evolutionary history of the lion, but may also play a crucial role in conservation efforts aimed at protecting the species in its full diversity.Environmental Biolog
Ultrastructural pathology of primary ciliary dyskinesia: report about 125 cases in Germany
<p>Abstract</p> <p>Background</p> <p>Primary ciliary dyskinesia (PCD) is a rare genetically induced disorder of cilia inducing mainly respiratory diseases. Transmission electron microscopy (TEM) analysis of ciliary ultrastructure is classically used for diagnosis. We report our experience of TEM investigations in a large series of patients.</p> <p>Methods</p> <p>TEM analysis performed of 742 biopsies from patients with suspected PCD was reviewed retrospectively. Ultrastructural defects were analysized further in 125 cases with changes typical for PCD.</p> <p>Results</p> <p>In 18.1% of patients diagnosis of PCD was made because of morphological alterations, in 68.2% secondary changes were seen. In 13.7% material was not feasible for analysis. Mostly defects of dynein arms were detected in PCD (96.8%). In particular defects of the inner arms (51.2%) and combined dynein defects (37.6%) were found. Total loss of dynein arms was dominant. Only in 3.2% deficiencies of central structures were found alone. Associated situs inversus or dextracardia was reported clinically in 21.4%.</p> <p>Conclusions</p> <p>TEM analysis is possible in most patients and a useful tool for diagnosis of PCD. Functional and genetic analysis should be done additionally. Registers should be installed to collect all available informations and push further research.</p
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