ORCID Profile
0000-0001-9337-0606
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Publisher: Springer Science and Business Media LLC
Date: 19-04-2016
DOI: 10.1038/SREP24627
Abstract: When faced with adverse environmental conditions, the marsupial Dromiciops gliroides uses either daily or seasonal torpor to support survival and is the only known hibernating mammal in South America. As the sole living representative of the ancient Order Microbiotheria, this species can provide crucial information about the evolutionary origins and biochemical mechanisms of hibernation. Hibernation is a complex energy-saving strategy that involves changes in gene expression that are elicited in part by microRNAs. To better elucidate the role of microRNAs in orchestrating hypometabolism, a modified stem-loop technique and quantitative PCR were used to characterize the relative expression levels of 85 microRNAs in liver and skeletal muscle of control and torpid D. gliroides . Thirty-nine microRNAs were differentially regulated during torpor of these, 35 were downregulated in liver and 11 were differentially expressed in skeletal muscle. Bioinformatic analysis predicted that the downregulated liver microRNAs were associated with activation of MAPK, PI3K-Akt and mTOR pathways, suggesting their importance in facilitating marsupial torpor. In skeletal muscle, hibernation-responsive microRNAs were predicted to regulate focal adhesion, ErbB, and mTOR pathways, indicating a promotion of muscle maintenance mechanisms. These tissue-specific responses suggest that microRNAs regulate key molecular pathways that facilitate hibernation, thermoregulation, and prevention of muscle disuse atrophy.
Publisher: Wiley
Date: 10-05-2016
DOI: 10.1002/ECE3.2097
Publisher: Wiley
Date: 23-05-2023
DOI: 10.1002/BIOF.1976
Abstract: The marsupial Monito del monte ( Dromiciops gliroides ) utilizes both daily and seasonal bouts of torpor to preserve energy and prolong survival during periods of cold and unpredictable food availability. Torpor involves changes in cellular metabolism, including specific changes to gene expression that is coordinated in part, by the posttranscriptional gene silencing activity of microRNAs (miRNA). Previously, differential miRNA expression has been identified in D . gliroides liver and skeletal muscle however, miRNAs in the heart of Monito del monte remained unstudied. In this study, the expression of 82 miRNAs was assessed in the hearts of active and torpid D . gliroides , finding that 14 were significantly differentially expressed during torpor. These 14 miRNAs were then used in bioinformatic analyses to identify Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways that were predicted to be most affected by these differentially expressed miRNAs. Overexpressed miRNAs were predicted to primarily regulate glycosaminoglycan biosynthesis, along with various signaling pathways such as Phosphoinositide‐3‐kinase rotein kinase B and transforming growth factor‐β. Similarly, signaling pathways including phosphatidylinositol and Hippo were predicted to be regulated by the underexpression of miRNAs during torpor. Together, these results suggest potential molecular adaptations that protect against irreversible tissue damage and enable continued cardiac and vascular function despite hypothermia and limited organ perfusion during torpor.
Publisher: Elsevier BV
Date: 10-2021
Publisher: Cold Spring Harbor Laboratory
Date: 13-08-2020
DOI: 10.1101/2020.08.12.207332
Abstract: Several geological events affecting Southern South America during the middle Miocene climatic optimum acted as important drivers of ersification to the biota. This is the case of Microbiotheria, for which Dromiciops is considered the sole surviving lineage, the sister group of Eomarsupialia (Australian marsupials). Three main Dromiciops genetic lineages are known, whose ergence was initially attributed to recent Pleistocene glaciations. Using fossil-calibrated dating on nuclear and mitochondrial genes, here we reevaluate this hypothesis and report an older (Miocenic) biogeographic history for the genus. Southern South America. Phylogenetic reconstruction using sequences from two mitochondrial DNA and four nuclear DNA genes in 159 specimens, from 31 sites across Chile and Argentina. Divergence time estimation using fossil calibration. Our phylogenetic analysis resolved four well supported clades with discrete geographic distributions. The oldest and most differentiated clade corresponds to that of the northern distribution (35.2°S to 39.3°S), which would be a different species ( D. bozinovici , sensu D’elia et al. 2016). According to our estimations, this species shared a common ancestor with D. gliroides (southern clades) about 13 million years ago (95% CI: 6.4-25.3). The southern clades (39.6°S to 42.0°S), showed a ergence time ranging from 9.57 to 6.5 Mya. Strong genetic structure was detected from north to south but not across the Andes, or between Chiloé island/ mainland. Demographic equilibrium is inferred to the northern clade, and recent demographic expansions was detected in the central and southern clades. The whole ersification of Dromiciops occurred within the Miocene, being the Middle Miocene transgression (MMT), the massive marine flooding that covered several lowlands of the western face of los Andes between 38-48° S, the most likely ersifying force. This was the result of an increase in global sea levels due to the Miocene climatic optimum, which shaped the biogeographic origin of several species, including Nothofagus forests, the habitat main of Dromiciops .
Publisher: Wiley
Date: 15-04-2018
DOI: 10.1002/ECE3.3979
Publisher: Elsevier BV
Date: 10-2018
DOI: 10.1016/J.CBPB.2017.12.005
Abstract: The South American marsupial, monito del monte (Dromiciops gliroides) uses both daily torpor and multi-day hibernation to survive in its southern Chile native environment. The present study leverages multiplex technology to assess the contributions of key stress-inducible cell cycle regulators and heat shock proteins to hibernation in liver, heart, and brain of monito del monte in a comparison of control versus 4day hibernating conditions. The data indicate that MDM2, a stress-responsive ubiquitin ligase, plays a crucial role in marsupial hibernation since all three tissues showed statistically significant increases in MDM2 levels during torpor (1.6-1.8 fold). MDM2 may have a cytoprotective action to deal with ischemia/reperfusion stress and is also involved in a nutrient sensing pathway where it could help regulate the metabolic switch to fatty acid oxidation during torpor. Elevated levels of stress-sensitive cell cycle regulators including ATR (2.32-3.91 fold), and the phosphorylated forms of p-Chk1 (Ser345) (1.92 fold), p-Chk2 (Thr68) (2.20 fold) and p21 (1.64 fold) were observed in heart and liver during hibernation suggesting that the cell cycle is likely suppressed to conserve energy while animals are in torpor. Upregulation of heat shock proteins also occurred as a cytoprotective strategy with increased levels of hsp27 (2.00 fold) and hsp60 (1.72-2.76 fold) during hibernation. The results suggest that cell cycle control and selective chaperone action are significant components of hibernation in D. gliroides and reveal common molecular responses to those seen in eutherian hibernators.
Publisher: Oxford University Press (OUP)
Date: 17-04-2016
DOI: 10.1111/ZOJ.12417
Publisher: Elsevier BV
Date: 10-2018
DOI: 10.1016/J.CBPB.2017.12.006
Abstract: When faced with harsh environmental conditions, the South American marsupial, monito del monte (Dromiciops gliroides), reduces its body temperature and uses either daily torpor or multiday hibernation to survive. This study used ELISA and multiplex assays to characterize the responses to hibernation by three regulatory components of protein translation machinery [p-eIF2α(S51), p-eIF4E(S209), p-4EBP(Thr37/46)] and eight targets involved in upstream signaling control of translation [p-IGF-1R(Tyr1135/1136), PTEN(S380), p-Akt(S473), p-GSK-3α(S21), p-GSK-3β(S9), p-TSC2(S939), p-mTOR(S2448), and p70S6K(T412)]. Liver, brain and kidney were analyzed comparing control and hibernation (4days continuous torpor) conditions. In the liver, increased phosphorylation of IGF-1R, Akt, GSK-3β, TSC2, mTOR, eIF2α, and 4EBP (1.60-1.98 fold compared to control) occurred during torpor suggesting that the regulatory phosphorylation cascade and protein synthesis remained active during torpor. However, responses by brain and kidney differed torpor resulted in increased phosphorylation of GSK-3β (2.15-4.17 fold) and TSC2 (2.03-3.65 fold), but phosphorylated Akt decreased (to 34-62% of control levels). Torpor also led to an increase in phosphorylated eIF2α (1.4 fold) content in the brain. These patterns of differential protein phosphorylation in brain and kidney were indicative of suppression of protein translation but also could suggest an increase in antioxidant and anti-apoptotic signaling during torpor. Previous studies of liver metabolism in hibernating eutherian mammals have shown that Akt kinase and its downstream signaling components play roles in facilitating hypometabolism by suppressing energy expensive anabolic processes during torpor. However, the results in this study reveal differences between eutherian and marsupial hibernators, suggesting alternative actions of liver Akt during torpor.
Publisher: Wiley
Date: 11-2018
DOI: 10.1111/MEC.14876
Abstract: The small South American marsupial, Dromiciops gliroides, known as the missing link between the American and the Australian marsupials, is one of the few South American mammals known to hibernate. Expressing both daily torpor and seasonal hibernation, this species may provide crucial information about the mechanisms and the evolutionary origins of marsupial hibernation. Here, we compared torpid and active in iduals, applying high-throughput sequencing technologies (RNA-seq) to profile gene expression in three D. gliroides tissues and determine whether hibernation induces tissue-specific differential gene expression. We found 566 transcripts that were significantly up-regulated during hibernation (369 in brain, 147 in liver and 50 in skeletal muscle) and 339 that were down-regulated (225 in brain, 79 in liver and 35 in muscle). The proteins encoded by these differentially expressed genes orchestrate multiple metabolic changes during hibernation, such as inhibition of angiogenesis, prevention of muscle disuse atrophy, fuel switch from carbohydrate to lipid metabolism, protection against reactive oxygen species and repair of damaged DNA. According to the global enrichment analysis, brain cells seem to differentially regulate a complex array of biological functions (e.g., cold sensitivity, circadian perception, stress response), whereas liver and muscle cells prioritize fuel switch and heat production for rewarming. Interestingly, transcripts of thioredoxin-interacting protein (TXNIP), a potent antioxidant, were significantly over-expressed during torpor in all three tissues. These results suggest that marsupial hibernation is a controlled process where selected metabolic pathways show adaptive modulation that can help to maintain homeostasis and enhance cytoprotection in the hypometabolic state.
Publisher: Elsevier BV
Date: 10-2018
DOI: 10.1016/J.CBPB.2017.12.007
Abstract: Hibernation is a period of torpor and heterothermy that is typically associated with a strong reduction in metabolic rate, global suppression of transcription and translation, and upregulation of various genes roteins that are central to the cellular stress response such as protein kinases, antioxidants, and heat shock proteins. The current study examined cell signaling cascades in hibernating monito del monte, Dromiciops gliroides, a South American marsupial of the Order Microbiotheria. Responses to hibernation by members of the mitogen-activated protein kinase (MAPK) pathways, and their roles in coordinating hibernator metabolism were examined in liver, kidney, heart and brain of control and versus hibernating (4days continuous torpor) D. gliroides. The targets evaluated included key protein kinases in their activated phosphorylated forms (p-ERK/MAPK 1/2, p-MEK1, p-MSK1, p-p38, p-JNK) and related target proteins (p-CREB 2, p-ATF2, p-c-Jun and p-p53). Liver exhibited a strong coordinated response by MAPK members to hibernation with significant increases in protein phosphorylation levels of p-MEK1, p-ERK/MAPK1/2, p-MSK1, p-JNK and target proteins c-Jun, and p-ATF2, all combining to signify a strong activation of MAPK signaling during hibernation. Kidney also showed activation of MAPK cascades with significant increases in p-MEK1, p-ERK/MAPK1/2, p-p38, and p-c-Jun levels in hibernating animals. By contrast, responses by heart and brain indicated reduced MAPK pathway function during torpor with reduced phosphorylation of targets including p-ERK/MAPK 1/2 in both tissues as well as lower p-p38 and p-JNK content in heart. Overall, the data indicate a vital role for MAPK signaling in regulating the cell stress response during marsupial hibernation.
Publisher: Elsevier BV
Date: 10-2018
DOI: 10.1016/J.CBPB.2017.12.008
Abstract: Mammalian hibernation is characterized by extensive adjustments to metabolism that typically include suppression of carbohydrate catabolism and a switch to triglycerides as the primary fuel during torpor. A crucial locus of control in this process is the pyruvate dehydrogenase complex that gates carbohydrate entry into the tricarboxylic acid cycle. Within the complex, the E1 enzyme pyruvate dehydrogenase (PDH) is the main regulatory site and is subject to inhibitory phosphorylation at three serine residues (S232, S293, S300). To determine if marsupial hibernators show a comparable focus on PDH to regulate fuel metabolism, the current study explored PDH control by site-specific phosphorylation in the South American marsupial, monito del monte (Dromiciops gliroides). Luminex multiplex technology was used to analyze PDH responses in six tissues comparing control and hibernating (4days continuous torpor) animals. Total PDH content did not change significantly during hibernation in any tissue but phospho-PDH content increased in all. Heart PDH showed increased phosphorylation at all three sites by 8.1-, 10.6- and 2.1-fold for S232, S293 and S300, respectively. Liver also showed elevated p-S300 (2.5-fold) and p-S293 (4.7-fold) content. Phosphorylation of S232 and S293 increased significantly in brain and lung but only S232 phosphorylation increased in kidney and skeletal muscle. The results show that PDH suppression via enzyme phosphorylation during torpor is a conserved mechanism for inhibiting carbohydrate catabolism in both marsupial and eutherian mammals, an action that would also promote the switch to fatty acid oxidation instead.
Publisher: Elsevier BV
Date: 03-2022
DOI: 10.1016/J.YMPEV.2022.107405
Abstract: Three orders represent the South American fauna of marsupials. Of these, Microbiotheria was until recently known as a monotypic genus with the only surviving species Dromiciops gliroides (monito del monte). The recent proposal of a new Dromiciops species (Dromiciops bozinovici), together with new information on the origin and ersification of living microbioterians has changed the prevailing paradigm around the evolutionary history of these emblematic marsupials. Here, we used a RADseq approach to test for evidence of admixture and past or current gene flow among both species of Dromiciops and evaluate the genetic structure within D. gliroides. We analyzed 127 s les of Dromiciops distributed across the known distribution range of both species. We also inferred the joint demographic history of these lineages, thus corroborating the status of D. bozinovici as a distinct species. Demographic history reconstruction indicated that D. bozinovici erged from D. gliroides around 4my ago and has remained isolated and demographically stable ever since. In contrast, D. gliroides is sub ided into three subclades that experienced recent expansions and moderate gene flow among them (mostly from north to south). Furthermore, genetic distances among populations within D. gliroides were significantly correlated with geographic distances. These results suggest that some of the D. gliroides populations would have survived in glacial refuges, with posterior expansions after ice retreat. Our results have important implications for the systematics of the genus and have profound conservation consequences for the new species, especially considering the fragmentation level of the temperate rainforest.
Publisher: MDPI AG
Date: 05-08-2023
DOI: 10.3390/ANI13152528
Abstract: The comparative phylogeography of marine species with contrasting dispersal potential across the southern Caribbean Sea was evaluated by the presence of two putative barriers: the Magdalena River plume (MRP) and the combination of the absence of a rocky bottom and the almost permanent upwelling in the La Guajira Peninsula (ARB + PUG). Three species with varying biological and ecological characteristics (i.e., dispersal potentials) that inhabit shallow rocky bottoms were selected: Cittarium pica (PLD 6 days), Acanthemblemaria rivasi (PLD 22 days), and Nerita tessellata (PLD 60 days). We generated a set of SNPs for the three species using the ddRad-seq technique. S les of each species were collected in five locations from Capurganá to La Guajira. For the first time, evidence of a phylogeographic break caused by the MRP is provided, mainly for A. rivasi (AMOVA: ΦCT = 0.420). The ARB + PUG barrier causes another break for A. rivasi (ΦCT = 0.406) and C. pica (ΦCT = 0.224). Three populations (K = 3) were identified for A. rivasi and C. pica, while N. tessellata presented one population (K = 1). The Mantel correlogram indicated that A. rivasi and C. pica fit the hierarchical population model, and only the A. rivasi and C. pica comparisons showed phylogeographic congruence. Our results demonstrate how the biological traits of these three species and the biogeographic barriers have influenced their phylogeographic structure.
Publisher: Springer Science and Business Media LLC
Date: 31-05-2016
DOI: 10.1038/SREP26853
Abstract: Marine blue mussels (Mytilus spp.) are widespread species that exhibit an antitropical distribution with five species occurring in the Northern Hemisphere ( M. trossulus , M. edulis , M. galloprovincialis , M. californianus and M. coruscus ) and three in the Southern Hemisphere ( M. galloprovincialis , M. chilensis and M. platensis ). Species limits in this group remain controversial, in particular for those forms that live in South America. Here we investigated structural characteristics of marine mussels mitogenomes, based on published F mtDNA sequences of Northern Hemisphere species and two newly sequenced South American genomes, one from the Atlantic M. platensis and another from the Pacific M. chilensis . These mitogenomes exhibited similar architecture to those of other genomes of Mytilus , including the presence of the Atp8 gene, which is missing in most of the other bivalves. Our evolutionary analysis of mitochondrial genes indicates that purifying selection is the predominant force shaping the evolution of the coding genes. Results of our phylogenetic analyses supported the monophyly of Pteriomorphia and fully resolved the phylogenetic relationships among its five orders. Finally, the low genetic ergence of specimens assigned to M. chilensis and M. platensis suggests that these South American marine mussels represent conspecific variants rather than distinct species.
Publisher: Wiley
Date: 03-2022
DOI: 10.1002/ECE3.8645
Abstract: The arboreal marsupial monito del monte (genus Dromiciops , with two recognized species) is a paradigmatic mammal. It is the sole living representative of the order Microbiotheria, the ancestor lineage of Australian marsupials. Also, this marsupial is the unique frugivorous mammal in the temperate rainforest, being the main seed disperser of several endemic plants of this ecosystem, thus acting as keystone species. Dromiciops is also one of the few hibernating mammals in South America, spending half of the year in a physiological dormancy where metabolism is reduced to 10% of normal levels. This capacity to reduce energy expenditure in winter contrasts with the enormous energy turnover rate they experience in spring and summer. The unique life history strategies of this living Microbiotheria, characterized by an alternation of life in the slow and fast lanes, putatively represent ancestral traits that permitted these cold‐adapted mammals to survive in this environment. Here, we describe the ecological role of this emblematic marsupial, summarizing the ecophysiology of hibernation and sociality, updated phylogeographic relationships, reproductive cycle, trophic relationships, mutualisms, conservation, and threats. This marsupial shows high densities, despite presenting slow reproductive rates, a paradox explained by the unique characteristics of its three‐dimensional habitat. We finally suggest immediate actions to protect these species that may be threatened in the near future due to habitat destruction and climate change.
No related grants have been discovered for Julian F. Quintero-Galvis.