Biogeographical affinity shapes relationships between ecological and phylogenetic mammal diversity and associations with their environmental correlates in the Americas

Zootaxa ◽  
2021 ◽  
Vol 5060 (3) ◽  
pp. 301-332
Author(s):  
PAULA NILDA FERGNANI ◽  
ADRIANA RUGGIERO
Keyword(s):  
Phylogenetic Diversity ◽  
Environmental Correlates ◽  
Continental Scale ◽  
Diversity Gradient ◽  
Evolutionarily Conserved ◽  
Positive Correlations ◽  
Regional Associations ◽  
The Tropics ◽  
Mammal Diversity

We evaluate the role of biogeographical affinity in shaping relationships between ecological diversity as a proxy of functional diversity and phylogenetic diversity and their association with environmental variation, across tropical and temperate latitudes of the Americas. If environmental niches are evolutionarily conserved, high mammal taxa of tropical and temperate affinity will show consistent differences in these relationships. Accordingly, mammal groups of tropical affinity (old-autochthonous: marsupials and xenarthrans; and mid-Cenozoic immigrants: hystricognaths and primates) show stronger positive correlations between ecological and phylogenetic diversity within the tropics than those from extra-tropical latitudes where newcomers from North America (artiodactyls) show the strongest positive correlations. The other group of newcomers (carnivorans), however, show a peak in the association that include both tropical and extra-tropical latitudes of South America. Climate predominates over topographic relief in structuring the spatial variation of ecological and phylogenetic mammal diversity. The environmental structuring of ecological and phylogenetic mammal diversity across the Americas is more complex than expected from a latitudinal diversity gradient. Dry seasonal tropical habitats generated considerable heterogeneity in relationships between ecological and phylogenetic diversity and their association with environmental correlates. We conclude that biogeographical affinity and regional associations between the different components of diversity and the environment should be considered for a comprehensive explanation of covariation between ecological and phylogenetic diversity on a continental scale.  

scholarly journals The role of extreme rain events in driving tree growth across a continental‐scale climatic range in Australia

Ecography ◽  
2021 ◽  
Author(s):  
Alison J. O'Donnell ◽  
Michael Renton ◽  
Kathryn J. Allen ◽  
Pauline F. Grierson
Keyword(s):  
Tree Growth ◽  
Continental Scale ◽  
Extreme Rain ◽  
Climatic Range ◽  
Rain Events

scholarly journals Emerging multifaceted roles of BAP1 complexes in biological processes

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Aileen Patricia Szczepanski ◽  
Lu Wang
Keyword(s):  
Transcriptional Repression ◽  
Target Genes ◽  
Regulatory Mechanisms ◽  
Biological Processes ◽  
Multiprotein Complex ◽  
Downstream Target ◽  
Evolutionarily Conserved ◽  
Complex Forms ◽  
Polycomb Repressive Complex 1

AbstractHistone H2AK119 mono-ubiquitination (H2AK119Ub) is a relatively abundant histone modification, mainly catalyzed by the Polycomb Repressive Complex 1 (PRC1) to regulate Polycomb-mediated transcriptional repression of downstream target genes. Consequently, H2AK119Ub can also be dynamically reversed by the BAP1 complex, an evolutionarily conserved multiprotein complex that functions as a general transcriptional activator. In previous studies, it has been reported that the BAP1 complex consists of important biological roles in development, metabolism, and cancer. However, identifying the BAP1 complex’s regulatory mechanisms remains to be elucidated due to its various complex forms and its ability to target non-histone substrates. In this review, we will summarize recent findings that have contributed to the diverse functional role of the BAP1 complex and further discuss the potential in targeting BAP1 for therapeutic use.

scholarly journals Evaluating the role of contracting and expanding rainforest in initiating cycles of speciation across the Isthmus of Panama

2012 ◽  
Vol 279 (1742) ◽  
pp. 3520-3526 ◽  
Author(s):  
Brian Tilston Smith ◽  
Amei Amei ◽  
John Klicka
Keyword(s):  
Bird Species ◽  
Tropical Regions ◽  
Isthmus Of Panama ◽  
Species Pairs ◽  
The Matrix ◽  
High Species Richness ◽  
The Rich ◽  
The Tropics ◽  
The Impact

Climatic and geological changes across time are presumed to have shaped the rich biodiversity of tropical regions. However, the impact climatic drying and subsequent tropical rainforest contraction had on speciation has been controversial because of inconsistent palaeoecological and genetic data. Despite the strong interest in examining the role of climatic change on speciation in the Neotropics there has been few comparative studies, particularly, those that include non-rainforest taxa. We used bird species that inhabit humid or dry habitats that dispersed across the Panamanian Isthmus to characterize temporal and spatial patterns of speciation across this barrier. Here, we show that these two assemblages of birds exhibit temporally different speciation time patterns that supports multiple cycles of speciation. Evidence for these cycles is further corroborated by the finding that both assemblages consist of ‘young’ and ‘old’ species, despite dry habitat species pairs being geographically more distant than pairs of humid habitat species. The matrix of humid and dry habitats in the tropics not only allows for the maintenance of high species richness, but additionally this study suggests that these environments may have promoted speciation. We conclude that differentially expanding and contracting distributions of dry and humid habitats was probably an important contributor to speciation in the tropics.

scholarly journals SWAT-Tb with improved LAI representation in the tropics highlights the role of forests in watershed regulation

2021 ◽  
Author(s):  
Santiago Valencia ◽  
Juan F. Salazar ◽  
Juan Camilo Villegas ◽  
Natalia Hoyos ◽  
Mateo Duque-Villegas
Keyword(s):  
The Tropics

Climate as the great equalizer of continental-scale erosion

2021 ◽  
Author(s):  
Gilby Jepson ◽  
Barbara Carrapa ◽  
Jack Gillespie ◽  
Ran Feng ◽  
Peter DeCelles ◽  
...  
Keyword(s):  
Central Asia ◽  
Regional Scale ◽  
Continental Scale ◽  
Active Tectonic ◽  
Tectonically Active ◽  
High Precipitation ◽  
Tectonic Boundaries ◽  
Great Equalizer ◽  
Tian Shan

<p>Central Asia is one of the most tectonically active and orographically diverse regions in the world and is the location of the highest topography on Earth resulting from major plate tectonic collisional events. Yet the role of tectonics versus climate on erosion remains one of the greatest debates of our time. We present the first regional scale analysis of 2526 published low-temperature thermochronometric dates from Central Asia spanning the Altai-Sayan, Tian Shan, Tibet, Pamir, and Himalaya. We compare these dates to tectonic processes (proximity to tectonic boundaries, crustal thickness, seismicity) and state-of-the-art paleoclimate simulations in order to constrain the relative influences of climate and tectonics on the topographic architecture and erosion of Central Asia. Predominance of pre-Cenozoic ages in much of the interior of central Asia suggests that significant topography was created prior to the India-Eurasia collision and implies limited subsequent erosion. Increasingly young cooling ages are associated with increasing proximity to active tectonic boundaries, suggesting a first-order control of tectonics on erosion. However, areas that have been sheltered from significant precipitation for extensive periods of time retain old cooling ages. This suggests that ultimately climate is the great equalizer of erosion. Climate plays a key role by enhancing erosion in areas with developed topography and high precipitation such as the Tian Shan and Altai-Sayan during the Mesozoic and the Himalaya during the Cenozoic. Older thermochronometric dates are associated with sustained aridity following more humid periods.</p>

scholarly journals MicroRNAs in Cardiac Autophagy: Small Molecules and Big Role

Cells ◽  
2018 ◽  
Vol 7 (8) ◽  
pp. 104 ◽  
Author(s):  
Teng Sun ◽  
Meng-Yang Li ◽  
Pei-Feng Li ◽  
Ji-Min Cao
Keyword(s):  
Cardiac Fibrosis ◽  
Heart Diseases ◽  
Critical Role ◽  
Transcriptional Gene Silencing ◽  
Close Link ◽  
Post Transcriptional Gene Silencing ◽  
Evolutionarily Conserved ◽  
Cardiac Disorders ◽  
Cellular Components

Autophagy, which is an evolutionarily conserved process according to the lysosomal degradation of cellular components, plays a critical role in maintaining cell homeostasis. Autophagy and mitochondria autophagy (mitophagy) contribute to the preservation of cardiac homeostasis in physiological settings. However, impaired or excessive autophagy is related to a variety of diseases. Recently, a close link between autophagy and cardiac disorders, including myocardial infarction, cardiac hypertrophy, cardiomyopathy, cardiac fibrosis, and heart failure, has been demonstrated. MicroRNAs (miRNAs) are a class of small non-coding RNAs with a length of approximately 21–22 nucleotides (nt), which are distributed widely in viruses, plants, protists, and animals. They function in mediating the post-transcriptional gene silencing. A growing number of studies have demonstrated that miRNAs regulate cardiac autophagy by suppressing the expression of autophagy-related genes in a targeted manner, which are involved in the pathogenesis of heart diseases. This review summarizes the role of microRNAs in cardiac autophagy and related cardiac disorders. Furthermore, we mainly focused on the autophagy regulation pathways, which consisted of miRNAs and their targeted genes.

scholarly journals Plasma Obestatin, Ghrelin, and Ghrelin/Obestatin Ratio Are Increased in Underweight Patients with Anorexia Nervosa But Not in Symptomatic Patients with Bulimia Nervosa

2008 ◽  
Vol 93 (11) ◽  
pp. 4418-4421 ◽  
Author(s):  
Palmiero Monteleone ◽  
Cristina Serritella ◽  
Vassilis Martiadis ◽  
Pasquale Scognamiglio ◽  
Mario Maj
Keyword(s):  
Anorexia Nervosa ◽  
Bulimia Nervosa ◽  
Energy Homeostasis ◽  
Physiological State ◽  
Blood Levels ◽  
Women Patients ◽  
Underweight Patients ◽  
Positive Correlations ◽  
Clinical Measures

Introduction: Peptides of the gut-brain axis have a pivotal role in the regulation of energy homeostasis. Obestatin, a sibling of ghrelin derived from preproghrelin, is thought to oppose ghrelin effects on food intake. Because changes in ghrelin levels have been associated with anorexia nervosa (AN) and bulimia nervosa (BN), the investigation of obestatin production may further contribute to understanding the role of peripheral peptides in patients with eating disorders. Methods: In the present study, we measured circulating blood levels of obestatin and ghrelin and assessed their relationships with anthropometric and clinical measures in 20 AN patients, 21 BN patients, and 20 appropriate healthy controls. Results: Compared with healthy women, patients with BN showed no significant differences in plasma obestatin and ghrelin concentrations and in the ghrelin/obestatin ratio, whereas underweight AN patients displayed significantly increased circulating levels of both obestatin (P < 0.009) and ghrelin (P < 0.002) and an increased ghrelin/obestatin ratio (P < 0.04). Moreover, in AN women, positive correlations emerged between the ghrelin/obestatin ratio and current body weight and body mass index. Conclusions: Underweight AN patients are characterized by increased concentrations of ghrelin and obestatin and a higher ghrelin to obestatin ratio. No changes in circulating ghrelin or obestatin as well as in ghrelin to obestatin ratio seem to occur in acutely ill patients with BN. Although those changes likely reflect the physiological state of symptomatic AN individuals, they may also contribute to the pathophysiology of the disorder.

scholarly journals Has erosion globally increased? Long-term erosion rates as a function of climate derived from the impact crater inventory

2018 ◽  
Author(s):  
Stefan Hergarten ◽  
Thomas Kenkmann
Keyword(s):  
Time Scale ◽  
Impact Crater ◽  
Regional Effect ◽  
Tropical Zone ◽  
Erosion Rates ◽  
Continental Scale ◽  
River Loads ◽  
The Impact

Abstract. Worldwide erosion rates seem to have increased strongly since the beginning of the Quaternary, but there is still discussion about the role of glaciation as a potential driver and even whether the increase is real at all or an artefact due to losses in the long-term sedimentary record. In this study we derive estimates of average erosion rates on the time scale of some tens of million years from the terrestrial impact crater inventory. This approach is completely independent from all other methods to infer erosion rates such as river loads, preserved sediments, cosmogenic nuclides and thermochronometry. Our approach yields average erosion rates as a function of present-day topography and climate. The results confirm that topography accounts for the main part of the huge variation of erosion on Earth, but also identifies a significant systematic dependence on climate in contrast to several previous studies. We found a fivefold increase in erosional efficacy from the cold regimes to the tropical zone and that temperate and arid climates are very similar in this context. Combining our results to a worldwide mean erosion rate we found that erosion rates on the time scale of some tens of million years are at least as high as present-day rates and suggest that glaciation has a rather regional effect with a limited impact at the continental scale.

scholarly journals Postrecruitment Function of Yeast Med6 Protein during the Transcriptional Activation by Mediator Complex

2018 ◽  
Vol 2018 ◽  
pp. 1-9
Author(s):  
Gwang Sik Kim ◽  
Young Chul Lee
Keyword(s):  
Gene Expression ◽  
Reporter Gene ◽  
Transcriptional Activation ◽  
Reporter Gene Expression ◽  
Temperature Sensitive ◽  
Internal Deletion ◽  
Cell Extracts ◽  
Evolutionarily Conserved

Med6 protein (Med6p) is a hallmark component of evolutionarily conserved Mediator complexes, and the genuine role of Med6p in Mediator functions remains elusive. For the functional analysis ofSaccharomyces cerevisiaeMed6p (scMed6p), we generated a series of scMed6p mutants harboring a small internal deletion. Genetic analysis of these mutants revealed that three regions (amino acids 33–42 (Δ2), 125–134 (Δ5), and 157–166 (Δ6)) of scMed6p are required for cell viability and are located at highly conserved regions of Med6 homologs. Notably, the Med6p-Δ2 mutant was barely detectable in whole-cell extracts and purified Mediator, suggesting a loss of Mediator association and concurrent rapid degradation. Consistent with this, the recombinant forms of Med6p having these mutations partially (Δ2) restore or fail (Δ5 and Δ6) to restore in vitro transcriptional defects caused by temperature-sensitivemed6mutation. In an artificial recruitment assay, Mediator containing a LexA-fused wild-type Med6p or Med6p-Δ5 was recruited to thelexAoperator region with TBP and activated reporter gene expression. However, the recruitment of Mediator containing LexA-Med6p-Δ6 tolexAoperator region resulted in neither TBP recruitment nor reporter gene expression. This result demonstrates a pivotal role of Med6p in the postrecruitment function of Mediator, which is essential for transcriptional activation by Mediator.

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