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1.
BMC Genomics ; 25(1): 826, 2024 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-39278943

RESUMO

The polar bear (Ursus maritimus) occupies a relatively narrow ecological niche, with many traits adapted for cold temperatures, movement across snow, ice and open water, and for consuming highly lipid-dense prey species. The divergence of polar bears from brown bears (Ursus arctos) and their adaptation to their Arctic lifestyle is a well-known example of rapid evolution. Previous research investigating whole genomes uncovered twelve key genes that are highly differentiated between polar and brown bears, show signatures of selection in the polar bear lineage, and are associated with polar bear adaptation to the Arctic environment. Further research suggested fixed derived alleles in these genes arose from selection on both standing variation and de novo mutations in the evolution of polar bears. Here, we reevaluate these findings based on a larger and geographically more representative dataset of 119 polar bears and 135 brown bears, and assess the timing of derived allele fixation in polar bears by incorporating the genomes of two Late Pleistocene individuals (aged 130-100,000 years old and 100-70,000 years old). In contrast with previous results, we found no evidence of derived alleles fixed in present-day polar bears within the key genes arising from de novo mutation. Most derived alleles fixed in present-day polar bears were also fixed in the Late Pleistocene polar bears, suggesting selection occurred prior to 70,000 years ago. However, some derived alleles fixed in present-day polar bears were not fixed in the two Late Pleistocene polar bears, including at sites within APOB, LYST, and TTN. These three genes are associated with cardiovascular function, metabolism, and pigmentation, suggesting selection may have acted on different loci at different times.


Assuntos
Alelos , Genoma , Ursidae , Ursidae/genética , Animais , Regiões Árticas , Adaptação Fisiológica/genética , Evolução Molecular , Seleção Genética
2.
Curr Biol ; 34(17): 3894-3904.e3, 2024 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-39127049

RESUMO

Globally, the majority of habitat loss is irreversible, and most species will never recover their former ranges. We have learned a great deal about what leads to population decline and extinction, but less about recovery. The recently downlisted giant panda provides a unique opportunity to understand the mechanisms of species recovery. In our study, we estimate giant panda suitable habitats, population density, and gene flow across landscapes to fully investigate the direct and indirect ecological mechanisms underlying bold conservation strategies. We found that the Giant Panda National Survey has modestly but systematically underestimated population size. China's effort to mitigate anthropogenic disturbances was associated with increased panda population density through improving habitat quality and reducing habitat fragmentation. Enhanced landscape connectivity reduced inbreeding via gene flow but indirectly increased inbreeding temporarily due to high local panda density. Although the panda's recovery has been geographically uneven, we provide evidence for improving connectivity and gene flow resulting from conservation efforts. If these processes can be sustained and improved, the panda's path to recovery will be less encumbered by loss of genetic diversity, fostering hope that the present rate of recovery will not be stalled. Findings from this study will not only help guide future giant panda conservation management but also provide a model for how a more mechanistic examination of the genetic processes underlying species recovery can foster the development of more effective strategies for endangered species recovery.


Assuntos
Conservação dos Recursos Naturais , Ecossistema , Fluxo Gênico , Ursidae , Ursidae/fisiologia , Ursidae/genética , Animais , Conservação dos Recursos Naturais/métodos , China , Densidade Demográfica , Espécies em Perigo de Extinção , Dinâmica Populacional
3.
Ecol Lett ; 27(8): e14486, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-39109607

RESUMO

The Arctic is warming four times faster than the rest of the world, threatening the persistence of many Arctic species. It is uncertain if Arctic wildlife will have sufficient time to adapt to such rapidly warming environments. We used genetic forecasting to measure the risk of maladaptation to warming temperatures and sea ice loss in polar bears (Ursus maritimus) sampled across the Canadian Arctic. We found evidence for local adaptation to sea ice conditions and temperature. Forecasting of genome-environment mismatches for predicted climate scenarios suggested that polar bears in the Canadian high Arctic had the greatest risk of becoming maladapted to climate warming. While Canadian high Arctic bears may be the most likely to become maladapted, all polar bears face potentially negative outcomes to climate change. Given the importance of the sea ice habitat to polar bears, we expect that maladaptation to future warming is already widespread across Canada.


Assuntos
Mudança Climática , Ursidae , Ursidae/genética , Animais , Canadá , Regiões Árticas , Adaptação Fisiológica , Camada de Gelo , Ecossistema , Temperatura
4.
Proc Natl Acad Sci U S A ; 121(36): e2406343121, 2024 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-39186654

RESUMO

The extinction risk of the giant panda has been demoted from "endangered" to "vulnerable" on the International Union for Conservation of Nature Red List, but its habitat is more fragmented than ever before, resulting in 33 isolated giant panda populations according to the fourth national survey released by the Chinese government. Further comprehensive investigations of the genetic background and in-depth assessments of the conservation status of wild populations are still necessary and urgently needed. Here, we sequenced the genomes of 612 giant pandas with an average depth of ~26× and generated a high-resolution map of genomic variation with more than 20 million variants covering wild individuals from six mountain ranges and captive representatives in China. We identified distinct genetic clusters within the Minshan population by performing a fine-grained genetic structure. The estimation of inbreeding and genetic load associated with historical population dynamics suggested that future conservation efforts should pay special attention to the Qinling and Liangshan populations. Releasing captive individuals with a genetic background similar to the recipient population appears to be an advantageous genetic rescue strategy for recovering the wild giant panda populations, as this approach introduces fewer deleterious mutations into the wild population than mating with differentiated lineages. These findings emphasize the superiority of large-scale population genomics to provide precise guidelines for future conservation of the giant panda.


Assuntos
Conservação dos Recursos Naturais , Genoma , Ursidae , Ursidae/genética , Animais , Conservação dos Recursos Naturais/métodos , Genoma/genética , China , Espécies em Perigo de Extinção , Variação Genética , Genética Populacional/métodos , Dinâmica Populacional , Sequenciamento Completo do Genoma/métodos
5.
J Hered ; 115(5): 498-506, 2024 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-39008331

RESUMO

The American black bear, Ursus americanus, is a widespread and ecologically important species in North America. In California, the black bear plays an important role in a variety of ecosystems and serves as an important species for recreational hunting. While research suggests that the populations in California are currently healthy, continued monitoring is critical, with genomic analyses providing an important surveillance tool. Here we report a high-quality, near chromosome-level genome assembly from a U. americanus sample from California. The primary assembly has a total length of 2.5 Gb contained in 316 scaffolds, a contig N50 of 58.9 Mb, a scaffold N50 of 67.6 Mb, and a BUSCO completeness score of 96%. This U. americanus genome assembly will provide an important resource for the targeted management of black bear populations in California, with the goal of achieving an appropriate balance between the recreational value of black bears and the maintenance of viable populations. The high quality of this genome assembly will also make it a valuable resource for comparative genomic analyses among black bear populations and among bear species.


Assuntos
Genoma , Ursidae , Ursidae/genética , Animais , California , Genômica/métodos
6.
Sci Total Environ ; 931: 172523, 2024 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-38657804

RESUMO

Landscape features can impede dispersal, gene flow, and population demography, resulting in the formation of several meta-populations within a continuous landscape. Understanding a species' ability to overcome these barriers is critical for predicting genetic connectivity and population persistence, and implementing effective conservation strategies. In the present study, we conducted a fine-scale spatial genetic analysis to understand the contemporary gene flow within red panda populations in the Eastern Himalayas. Employing geometric aspects of reserve design, we delineated the critical core habitats for red pandas, which comprise 14.5 % of the landscape (12,189.75 Km2), with only a mere 443 Km2 falling within the protected areas. We identified corridors among the core habitats, which may be vital for the species' long-term genetic viability. Furthermore, we identified substantial landscape barriers, including Sela Pass in the western region, Siang river in the central region, and the Dibang river, Lohit river, along with Dihang, Dipher, and Kumjawng passes in the eastern region, which hinder gene flow. We suggest managing red panda populations through the creation of Community Conservation Reserves in the identified core habitats, following landscape-level management planning based on the core principles of geometric reserve design. This includes a specific emphasis on identified core habitats of red panda (CH-RP 5 and CH-RP 8) to facilitate corridors and implement meta-population dynamics. We propose the development of a comprehensive, long-term conservation and management plan for red pandas in the transboundary landscape, covering China, Nepal, and Bhutan.


Assuntos
Conservação dos Recursos Naturais , Ecossistema , Fluxo Gênico , Ursidae , Animais , Ursidae/genética , China , Distribuição Animal , Himalaia
7.
Sci Rep ; 14(1): 7343, 2024 03 28.
Artigo em Inglês | MEDLINE | ID: mdl-38538629

RESUMO

Contact between humans and wildlife presents a risk for both zoonotic and anthropozoonotic disease transmission. In this study we report the detection of human strains of Mycobacterium tuberculosis in sun bears and an Asiatic black bear in a wildlife rescue centre in Cambodia, confirming for the first time the susceptibility of these bear species to tuberculosis when in close contact with humans. After genotyping revealed two different strains of M. tuberculosis from cases occurring between 2009 and 2019, 100 isolates from 30 sun bear cases, a single Asiatic black bear case, and a human case were subjected to whole genome sequencing. We combined single nucleotide polymorphism analysis and exploration of mixed base calls with epidemiological data to indicate the evolution of each outbreak. Our results confirmed two concurrent yet separate tuberculosis outbreaks and established a likely transmission route in one outbreak where the human case acted as an intermediatory between bear cases. In both outbreaks, we observed high rates of transmission and progression to active disease, suggesting that sun bears are highly susceptible to tuberculosis if exposed under these conditions. Overall, our findings highlight the risk of bi-directional transmission of tuberculosis between humans and captive bears in high human tuberculosis burden regions, with implied considerations for veterinary and public health. We also demonstrate the use of standard genomic approaches to better understand disease outbreaks in captive wildlife settings and to inform control and prevention measures.


Assuntos
Tuberculose , Ursidae , Animais , Humanos , Ursidae/genética , Camboja/epidemiologia , Surtos de Doenças , Tuberculose/epidemiologia , Tuberculose/veterinária , Genômica
8.
Mol Ecol Resour ; 24(5): e13956, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38553977

RESUMO

The development of epigenetic clocks, or the DNA methylation-based inference of age, is an emerging tool for ageing in free ranging populations. In this study, we developed epigenetic clocks for three species of large mammals that are the focus of extensive management throughout their range in North America: white-tailed deer, black bear and mountain goat. We quantified differential DNA methylation patterns at over 30,000 cytosine-guanine sites (CpGs) from tissue samples of all three species (black bear n = 49; white-tailed deer n = 47; mountain goat n = 45). We used a penalized regression model (elastic net) to build explanatory (black bear r = .95; white-tailed deer r = .99; mountain goat r = .97) and robust (black bear Median Absolute Error or MAE = 1.33; white-tailed deer MAE = 0.29; mountain goat MAE = 0.61) models of age or clocks. We also characterized individual CpG sites within each species that demonstrated clear differences in methylation levels between age classes and sex, which can be used to develop a suite of accessible diagnostic markers. This tool has the potential to contribute to wildlife monitoring by providing easily obtainable representations of age structure in managed populations.


Assuntos
Metilação de DNA , Cervos , Epigênese Genética , Animais , Metilação de DNA/genética , Cervos/genética , Cervos/classificação , Epigênese Genética/genética , Ursidae/genética , Ursidae/classificação , Feminino , Masculino , Ilhas de CpG/genética , Envelhecimento/genética , América do Norte , Cabras/genética
9.
Proc Natl Acad Sci U S A ; 121(11): e2317430121, 2024 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-38437540

RESUMO

Brown-and-white giant pandas (hereafter brown pandas) are distinct coat color mutants found exclusively in the Qinling Mountains, Shaanxi, China. However, its genetic mechanism has remained unclear since their discovery in 1985. Here, we identified the genetic basis for this coat color variation using a combination of field ecological data, population genomic data, and a CRISPR-Cas9 knockout mouse model. We de novo assembled a long-read-based giant panda genome and resequenced the genomes of 35 giant pandas, including two brown pandas and two family trios associated with a brown panda. We identified a homozygous 25-bp deletion in the first exon of Bace2, a gene encoding amyloid precursor protein cleaving enzyme, as the most likely genetic basis for brown-and-white coat color. This deletion was further validated using PCR and Sanger sequencing of another 192 black giant pandas and CRISPR-Cas9 edited knockout mice. Our investigation revealed that this mutation reduced the number and size of melanosomes of the hairs in knockout mice and possibly in the brown panda, further leading to the hypopigmentation. These findings provide unique insights into the genetic basis of coat color variation in wild animals.


Assuntos
Ursidae , Animais , Camundongos , Ursidae/genética , Peptídeo Hidrolases , Precursor de Proteína beta-Amiloide , Animais Selvagens , Camundongos Knockout
10.
Sci Rep ; 14(1): 2745, 2024 02 02.
Artigo em Inglês | MEDLINE | ID: mdl-38302507

RESUMO

The objective of this study was to analyze the antimicrobial resistance (AMR) characteristics produced by antibiotic resistance genes (ARGs), mobile genetic elements (MGEs) and gene cassettes in Escherichia coli isolated from the feces of captive black bears. Antimicrobial susceptibility testing was performed by using the disk diffusion method, and both MGEs and integron gene cassettes were detected by polymerase chain reaction. Our results showed that 43.7% (62/142) of the isolates were multidrug resistant strains and 97.9% (139/142) of the isolates were resistant to at least one antibiotic. The highest AMR phenotype was observed for tetracycline (79.6%, 113/142), followed by ampicillin (50.0%, 71/142), trimethoprim-sulfamethoxazole (43.7%, 62/142) and cefotaxime (35.9%, 51/142). However, all isolates were susceptible to tobramycin. tetA had the highest occurrence in 6 ARGs in 142 E. coli isolates (76.8%, 109/142). Ten mobile genetic elements were observed and IS26 was dominant (88.0%, 125/142). ISECP1 was positively associated with five ß-lactam antibiotics. ISCR3/14, IS1133 and intI3 were not detected. Seventy-five E. coli isolates (65 intI1-positive isolates, 2 intI2-positive isolates and 8 intI1 + intI2-positive isolates) carried integrons. Five gene cassettes (dfrA1, aadA2, dfrA17-aadA5, aadA2-dfrA12 and dfrA1-aadA1) were identified in the intI1-positive isolates and 2 gene cassettes (dfrA1-catB2-sat2-aadA1 and dfrA1-catB2-sat1-aadA1) were observed in the intI2-positive isolates. Monitoring of ARGs, MGEs and gene cassettes is important to understand the prevalence of AMR, which may help to introduce measures to prevent and control of AMR in E. coli for captive black bears.


Assuntos
Escherichia coli , Ursidae , Animais , Antibacterianos/farmacologia , Ursidae/genética , Farmacorresistência Bacteriana/genética , Integrons/genética
11.
Sci Rep ; 14(1): 2834, 2024 02 03.
Artigo em Inglês | MEDLINE | ID: mdl-38310153

RESUMO

Wildlife conservation in Andean countries is a global priority because of the high levels of biodiversity and endemism. Historically, these countries have had limited resources to monitor wildlife (e.g., through genetic tools) and establish conservation programs. Focusing on the study and emblematic use of a few charismatic species has been a strategic approach to direct efforts for conservation and development planning. Consequently, the Andean bear is a flagship and umbrella species for highly biodiverse Andean countries like Ecuador. The few studies exploring the population genetics of this species have concluded that it has low genetic diversity and few units for conservation as populations appear to be well connected. However, these results might be attributed to ascertainment bias as studies have been performed with heterologous molecular markers. Here, using both mtDNA sequences and species-specific microsatellite markers, we show that Andean bears in Ecuador have population structure. Additionally, we found through the study of three Ecuadorian populations that the species might have a higher genetic diversity than we previously thought. These results could support the revision of research priorities, conservation, and planning strategies to improve connectivity for this species which occurs in crucial biodiversity hotspots.


Assuntos
Ursidae , Animais , Equador , Ursidae/genética , Genética Populacional , Biodiversidade , Conservação dos Recursos Naturais , Variação Genética
12.
Vet Med Sci ; 10(1): e1348, 2024 01.
Artigo em Inglês | MEDLINE | ID: mdl-38227708

RESUMO

Testicular tumours are zoonoses that can occur in not only human, but other animals, include giant pandas. A middle-aged male giant panda named Fufu was diagnosed with a testicular tumour and underwent surgery to remove the entire left testis. The testis was mainly composed of three substantive parts: normal tissue on the outside, tumour tissue in the middle, and necrosis in the centre. HE stains revealed that the tumour was a seminoma. Single-cell mRNA sequence was applied to characterise cellular states and molecular circuitries of giant panda testicular seminoma. Only germ cell markers expressed in nearly all tumour cells, and the tumour cells appeared to be the same subtype of seminoma cells. We identified four clusters with unique genes expression. They were early apoptosis cells (EAC), inactive cells (IC), active cells subcluster 1 (AC-1) and active cells subcluster 2 (AC-2). We utilised monocle tools and found that IC cells was in the initiation stage, and EAC was one type of terminal stage, suggesting that tumour cells may undergo apoptosis in the future. AC-2 was another type of terminal stage, representing a group of progressive cells. Our study represents the first report to utilise scRNA-seq to characterise the cellular states and molecular circuitries of a giant panda testicular tumour. This investigation proposes CD117 and CD30 as dependable markers for future pathologic diagnosis. Our findings also suggest that CTSV and other genes with unique expression patterns in active and progressive giant panda seminoma cells may act as early prognostic biomarkers.


Assuntos
Seminoma , Neoplasias Testiculares , Ursidae , Masculino , Humanos , Animais , Ursidae/genética , Seminoma/genética , Seminoma/veterinária , Expressão Gênica , RNA Mensageiro , Neoplasias Testiculares/veterinária
13.
Conserv Biol ; 38(1): e14197, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37811741

RESUMO

Hybridization is an important evolutionary force with a principal role in the origin of new species, known as hybrid speciation. However, ongoing hybridization can create hybrid swamping, in which parental genomes are completely lost. This can become a biodiversity threat if it involves species that have adapted to certain environmental conditions and occur nowhere else. Because conservation scientists commonly have a negative attitude toward hybrids, it is important to improve understanding of the influence of interspecific gene flow on the persistence of species. We reviewed the literature on species hybridization to build a list of all known cases in the order Carnivora. To examine the relative impact, we also noted level of introgression, whether fertile offspring were produced, and whether there was mention of negative or positive evolutionary effects (hybrid speciation and swamping). To evaluate the conservation implications of hybrids, we developed a decision-making tree with which to determine which actions should be taken to manage hybrid species. We found 53 hybrids involving 68 unique taxa, which is roughly 23% of all carnivore species. They mainly involved monophyletic (83%) and sympatric species (75%). For 2 species, the outcome of the assessment was to eliminate or restrict the hybrids: Ethiopian wolf (Canis simensis) and Scottish wildcat (Felis silvestris silvestris). Both species hybridize with their domestic conspecifics. For all other cases, we suggest hybrids be protected in the same manner as native species. We found no evidence of genomic extinction in Carnivora. To the contrary, some species appear to be of hybrid origin, such as the Asiatic black bear (Ursus thibetanus) and African golden wolf (Canis lupaster). Other positive outcomes of hybridization are novel genetic diversity, adaptation to extreme environments, and increased reproductive fitness. These outcomes are particularly valuable for counterbalancing genetic drift and enabling adaptive introgression in a human-dominated world.


La especiación por hibridación es una fuerza evolutiva importante con un papel principal en el origen de una nueva especie. Sin embargo, la hibridación continua puede generar un estancamiento híbrido en el que se pierden por completo los genomas parentales. Esto puede convertirse en una amenaza para la biodiversidad si involucra a una especie que se ha adaptado a ciertas condiciones ambientales y sólo se encuentra en un lugar. Ya que los científicos de la conservación suelen tener una actitud negativa hacia los híbridos, es importante incrementar el entendimiento de la influencia que tiene el flujo interespecífico sobre la persistencia de las especies. Revisamos la literatura sobre la hibridación de especies para generar una lista de todos los casos conocidos en el orden Carnívora. También observamos el nivel de introgresión, si se produjo descendencia fértil y si hubo mención de los efectos evolutivos positivos o negativos (especiación híbrida y estancamiento) para analizar el impacto relativo. Desarrollamos un árbol de decisión con el cual determinar cuáles acciones deberían tomarse en el manejo de las especies híbridas para evaluar las implicaciones que tienen los híbridos para la conservación. Encontramos 53 híbridos de 68 taxones únicos, lo que representa aproximadamente el 23% de todos los carnívoros. Estos híbridos incluyen principalmente a especies monofiléticas (83%) y simpátricas (75%). Para dos especies, los resultados del análisis fueron la eliminación o restricción de los híbridos: el lobo etíope (Canis simensis) y el lince escocés (Felis silvestris silvestris). Ambas especies hibridan con sus coespecíficos domésticos. Para todos los demás casos sugerimos que se proteja a los híbridos de la misma manera que a las especies nativas. No encontramos evidencias de una extinción genómica en el orden Carnívora. Al contrario, algunas especies parecen tener un origen híbrido, como el oso negro asiático (Ursus thibetanus) y el lobo dorado africano (Canis lupaster). Otros resultados positivos de la hibridación son la diversidad genética novedosa, la adaptación a ambientes extremos y el incremento en la adaptabilidad reproductiva. Estos resultados son de valor particular para contrarrestar la deriva génica y permitir la introgresión adaptativa en un mundo dominado por humanos. Evaluación de la especiación y estancamiento en carnívoros silvestres con una estrategia de árbol de decisión.


Assuntos
Ursidae , Lobos , Animais , Humanos , Conservação dos Recursos Naturais , Evolução Biológica , Hibridização Genética , Ursidae/genética , Árvores de Decisões
14.
Annu Rev Anim Biosci ; 12: 69-89, 2024 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-37863091

RESUMO

Giant pandas and red pandas are endangered species with similar specialized bamboo diet and partial sympatric distribution in China. Over the last two decades, the rapid development of genomics and metagenomics research on these species has enriched our knowledge of their biology, ecology, physiology, genetics, and evolution, which is crucial and useful for their conservation. We describe the evolutionary history, endangerment processes, genetic diversity, and population structure of wild giant pandas and two species of red pandas (Chinese and Himalayan red pandas). In addition, we explore how genomics and metagenomics studies have provided insight into the convergent adaptation of pandas to the specialized bamboo diet. Finally, we discuss how these findings are applied to effective conservation management of giant and red pandas in the wild and in captivity to promote the long-term persistence of these species.


Assuntos
Ursidae , Animais , Ursidae/genética , Genômica
15.
Mol Ecol Resour ; 24(3): e13915, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38099394

RESUMO

Continued advancements in environmental DNA (eDNA) research have made it possible to access intraspecific variation from eDNA samples, opening new opportunities to expand non-invasive genetic studies of wildlife populations. However, the use of eDNA samples for individual genotyping, as typically performed in non-invasive genetics, still remains elusive. We present successful individual genotyping of eDNA obtained from snow tracks of three large carnivores: brown bear (Ursus arctos), European lynx (Lynx lynx) and wolf (Canis lupus). DNA was extracted using a protocol for isolating water eDNA and genotyped using amplicon sequencing of short tandem repeats (STR), and for brown bear a sex marker, on a high-throughput sequencing platform. Individual genotypes were obtained for all species, but genotyping performance differed among samples and species. The proportion of samples genotyped to individuals was higher for brown bear (5/7) and wolf (7/10) than for lynx (4/9), and locus genotyping success was greater for brown bear (0.88). The sex marker was typed in six out of seven brown bear samples. Results for three species show that reliable individual genotyping, including sex identification, is now possible from eDNA in snow tracks, underlining its vast potential to complement the non-invasive genetic methods used for wildlife. To fully leverage the application of snow track eDNA, improved understanding of the ideal species- and site-specific sampling conditions, as well as laboratory methods promoting genotyping success, is needed. This will also inform efforts to retrieve and type nuclear DNA from other eDNA samples, thereby advancing eDNA-based individual and population-level studies.


Assuntos
DNA Ambiental , Lynx , Ursidae , Lobos , Humanos , Animais , Ursidae/genética , Lobos/genética , Neve , Lynx/genética , DNA/genética , Genótipo , Animais Selvagens/genética
16.
J Comp Physiol B ; 193(6): 699-713, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37819371

RESUMO

Hibernation is a highly seasonal physiological adaptation that allows brown bears (Ursus arctos) to survive extended periods of low food availability. Similarly, daily or circadian rhythms conserve energy by coordinating body processes to optimally match the environmental light/dark cycle. Brown bears express circadian rhythms in vivo and their cells do in vitro throughout the year, suggesting that these rhythms may play important roles during periods of negative energy balance. Here, we use time-series analysis of RNA sequencing data and timed measurements of ATP production in adipose-derived fibroblasts from active and hibernation seasons under two temperature conditions to confirm that rhythmicity was present. Culture temperature matching that of hibernation body temperature (34 °C) resulted in a delay of daily peak ATP production in comparison with active season body temperatures (37 °C). The timing of peaks of mitochondrial gene transcription was altered as were the amplitudes of transcripts coding for enzymes of the electron transport chain. Additionally, we observed changes in mean expression and timing of key metabolic genes such as SIRT1 and AMPK which are linked to the circadian system and energy balance. The amplitudes of several circadian gene transcripts were also reduced. These results reveal a link between energy conservation and a functioning circadian system in hibernation.


Assuntos
Hibernação , Ursidae , Animais , Ursidae/genética , Hibernação/genética , Ritmo Circadiano/fisiologia , Transcrição Gênica , Trifosfato de Adenosina , Estações do Ano
17.
BMC Biol ; 21(1): 222, 2023 10 20.
Artigo em Inglês | MEDLINE | ID: mdl-37858133

RESUMO

BACKGROUND: Energy homeostasis is essential for the adaptation of animals to their environment and some wild animals keep low metabolism adaptive to their low-nutrient dietary supply. Giant panda is such a typical low-metabolic mammal exhibiting species specialization of extremely low daily energy expenditure. It has low levels of basal metabolic rate, thyroid hormone, and physical activities, whereas the cellular bases of its low metabolic adaptation remain rarely explored. RESULTS: In this study, we generate a single-nucleus transcriptome atlas of 21 organs/tissues from a female giant panda. We focused on the central metabolic organ (liver) and dissected cellular metabolic status by cross-species comparison. Adaptive expression mode (i.e., AMPK related) was prominently displayed in the hepatocyte of giant panda. In the highest energy-consuming organ, the heart, we found a possibly optimized utilization of fatty acid. Detailed cell subtype annotation of endothelial cells showed the uterine-specific deficiency of blood vascular subclasses, indicating a potential adaptation for a low reproductive energy expenditure. CONCLUSIONS: Our findings shed light on the possible cellular basis and transcriptomic regulatory clues for the low metabolism in giant pandas and helped to understand physiological adaptation response to nutrient stress.


Assuntos
Ursidae , Animais , Feminino , Ursidae/genética , Ursidae/metabolismo , Transcriptoma , Células Endoteliais , Animais Selvagens , Exercício Físico
18.
Forensic Sci Int Genet ; 67: 102935, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37797418

RESUMO

Demand for bear bile, a prized component of traditional Asian medicines, threaten Asiatic and sun bear population sustainability. While laws exist to prevent poaching and trafficking of bear parts and derivatives, smuggling persists with demand extending to surrogate species, including American black bears (Ursus americanus). Mitochondrial DNA (mtDNA) sequencing can identify products putatively containing biological bear material but can be undermined by PCR inhibitors in bile and a lack of sensitivity at trace levels. Quantitative PCR (qPCR) assays can be used to distinguish between closely related target species, while concomitantly evaluating inhibition and false negative results in low quality/quantity DNA applications. Herein, we develop a multiplexed qPCR assay to detect and differentiate among bear species, including highly diluted bile samples mixed within liquors as common dilutants. The assay detects as little as 10 locus copies/reaction of bear DNA with 95% confidence, distinguishing among sun, Asiatic and American black bears. Demonstrating the sensitivity and applicability of this assay in context of current bile mixture recipes, dilutions of 1:5,000 bile with ethanol, red wine, and spirits, all yielded clear quantifiable detections, where our data suggests as little as 1 drop of bile per 750 mL bottle of alcohol would still exceed the limits of detection (e.g., 1:15000 dilution or <0.05 mL bile per 750 mL bottle). Overall, this study provides a rapid, sensitive, and specific test to identify and distinguish among bear species commonly used for bile production to aid wildlife enforcement applications.


Assuntos
Bile , Ursidae , Humanos , Animais , Animais Selvagens/genética , Ursidae/genética , Reação em Cadeia da Polimerase , DNA Mitocondrial/genética
19.
In Vitro Cell Dev Biol Anim ; 59(7): 550-563, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37639049

RESUMO

Conservation of genetic resources is an important way to protect endangered species. At present, mesenchymal stem cells (MSCs) have been isolated from the bone marrow and umbilical cords of giant pandas. However, the types and quantities of preserved cell resources were rare and limited, and none of MSCs was derived from female reproductive organs. Here, we first isolated MSCs from the endometrium of giant panda. These cells showed fibroblast morphology and expressed Sox2, Klf4, Thy1, CD73, CD105, CD44, CD49f, and CD105. Endometrium mesenchymal stem cells (eMSCs) of giant panda could induce differentiation into three germ layers in vitro. RNA-seq analysis showed that 833 genes were upregulated and 716 genes were downregulated in eMSCs compared with skin fibroblast cells. The results of GO and the KEGG analysis of differentially expressed genes (DEGs) were mainly focused on transporter activity, signal transducer activity, pathways regulating pluripotency of stem cells, MAPK signaling pathway, and PI3K-Akt signaling pathway. The genes PLCG2, FRK, JAK3, LYN, PIK3CB, JAK2, CBLB, and MET were identified as hub genes by PPI network analysis. In addition, the exosomes of eMSCs were also isolated and identified. The average diameter of exosomes was 74.26 ± 13.75 nm and highly expressed TSG101 and CD9 but did not express CALNEXIN. A total of 277 miRNAs were detected in the exosomes; the highest expression of miRNA was the has-miR-21-5p. A total of 14461 target genes of the whole miRNAs were predicted and proceeded with functional analysis. In conclusion, we successfully isolated and characterized the giant panda eMSCs and their exosomes, and analyzed their functions through bioinformatics techniques. It not only enriched the conservation types of giant panda cell resources and promoted the protection of genetic diversity, but also laid a foundation for the application of eMSCs and exosomes in the disease treatment of giant pandas.


Assuntos
Exossomos , Células-Tronco Mesenquimais , MicroRNAs , Ursidae , Feminino , Animais , Ursidae/genética , Exossomos/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Células-Tronco Mesenquimais/metabolismo , MicroRNAs/genética , Endométrio/metabolismo
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