Constraining Cenozoic Exhumation in Southeastern Colorado and Eastern New Mexico Using Low-temperature Thermochronology

The current elevation of the Southern Rocky Mountains and adjacent Great Plains are too high to be explained by crustal shortening during the Laramide Orogeny alone. Instead, we suggest that a later episode of epeirogeny affected the area. The mechanism behind this is ambiguous, but by constraining where and when potential Cenozoic uplift occurred, a more concrete history can be established. Surface uplift is often linked to exhumation via increased rates of erosion. This study focuses on finding spatial and temporal trends of exhumation in southeast Colorado and eastern New Mexico via low-temperature thermochronology, with the goal of linking regional thermal histories of multiple areas.&nbsp; New apatite (U-Th)/He (AHe) data from the Spanish Peaks and surrounding basins in south-central Colorado present dates from 18-8 Ma, allowing us to infer kilometer-scale exhumation took place during the Miocene. Slightly older dates are found in the Chico Hills of northeast New Mexico at 22-13 Ma. At Two Buttes, 200km east of the Spanish Peaks in the Great Plains, an older Oligocene exhumation is observed (27.1 ∓ 4 Ma). To constrain the southern extent of this area, in central-eastern New Mexico, AHe and apatite fission track (AFT) data (Landman, 2016; Kelley &amp; Chapin, 1995; Kelley &amp; Duncan, 1986) were analyzed, showing a similar Oligo-Miocene, eastward oldening trend. Landman (2016) also found Oligocene AHe at Capitan Pluton in southern New Mexico. Overall data patterns show mid-Miocene exhumation taking place in east-central New Mexico, with dates getting older to the west, east, and south. This pattern of erosion is best explained through regional epeirogeny with the focus of a more rapid and recent uplift being in east-central New Mexico. Only the Spanish Peaks region is inconsistent with this trend, with dates as young as 8 Ma being found. We hypothesize these youngest AHe dates are due to possible drainage reorganization of the Arkansas River that may have rerouted through the Great Plains of Colorado at 5-10 Ma.&nbsp;</p

Cenozoic Exhumation Across the High Plains of Southeastern Colorado from (U-Th)/He Thermochronology

Colorado’s High Plains stand at anomalously high elevations (~1300–2100 m) for their continental interior setting, but when and why this region became elevated is poorly understood. The Cenozoic history of the High Plains is also likely linked with that of the Rocky Mountains, where the timing and cause(s) of uplift are similarly debated. We present apatite (U-Th)/He (AHe) data for 10 samples from Tertiary intrusives along a ~200 km west-to-east transect across the High Plains of southeastern Colorado to constrain the timing of exhumation and to gain insight into when and why regional elevation gain occurred. Mean sample AHe dates for the ~24–22 Ma East Spanish Peak pluton and associated radial dikes from the westernmost High Plains are 18.8 ± 1.4 to 14.1 ± 1.7 Ma, recording substantial postemplacement erosion. AHe results for the mafic to ultramafic Apishapa Dikes (oldest ~37 Ma, youngest ~14 Ma) located ~20–40 km farther north and east on the High Plains range from 12.0 ± 1.4 to 6.2 ± 1.9 Ma, documenting continued exhumation on the western High Plains during the ~12–5 Ma deposition of the Ogallala Formation farther east and suggesting that the western limit of Ogallala deposition was east of the Apishapa Dikes. In far southeastern Colorado, the Two Buttes lamprophyre was emplaced at 36.8 ± 0.4 Ma and yields a Late Oligocene AHe date of 27.1 ± 4 Ma. Here, the Ogallala Formation unconformably overlies Two Buttes, indicating that the regional ~12 Ma age for the base of the Ogallala is a minimum age for the exposure of the pluton at the surface. The AHe data presented here document that kilometer-scale erosion affected all of the southeastern Colorado High Plains in Oligo-Miocene time. While exhumation can have multiple possible causes, we favor contemporaneous surface uplift capable of elevating the region to modern heights

Cenozoic Exhumation Across the High Plains of Southeastern Colorado from (U-Th)/He Thermochronology

Colorado&rsquo;s High Plains stand at anomalously high elevations (~1300&ndash;2100 m) for their continental interior setting, but when and why this region became elevated is poorly understood. The Cenozoic history of the High Plains is also likely linked with that of the Rocky Mountains, where the timing and cause(s) of uplift are similarly debated. We present apatite (U-Th)/He (AHe) data for 10 samples from Tertiary intrusives along a ~200 km west-to-east transect across the High Plains of southeastern Colorado to constrain the timing of exhumation and to gain insight into when and why regional elevation gain occurred. Mean sample AHe dates for the ~24&ndash;22 Ma East Spanish Peak pluton and associated radial dikes from the westernmost High Plains are 18.8 &plusmn; 1.4 to 14.1 &plusmn; 1.7 Ma, recording substantial postemplacement erosion. AHe results for the mafic to ultramafic Apishapa Dikes (oldest ~37 Ma, youngest ~14 Ma) located ~20&ndash;40 km farther north and east on the High Plains range from 12.0 &plusmn; 1.4 to 6.2 &plusmn; 1.9 Ma, documenting continued exhumation on the western High Plains during the ~12&ndash;5 Ma deposition of the Ogallala Formation farther east and suggesting that the western limit of Ogallala deposition was east of the Apishapa Dikes. In far southeastern Colorado, the Two Buttes lamprophyre was emplaced at 36.8 &plusmn; 0.4 Ma and yields a Late Oligocene AHe date of 27.1 &plusmn; 4 Ma. Here, the Ogallala Formation unconformably overlies Two Buttes, indicating that the regional ~12 Ma age for the base of the Ogallala is a minimum age for the exposure of the pluton at the surface. The AHe data presented here document that kilometer-scale erosion affected all of the southeastern Colorado High Plains in Oligo-Miocene time. While exhumation can have multiple possible causes, we favor contemporaneous surface uplift capable of elevating the region to modern heights. &nbsp;</p

Targeting GATA transcription factors – a novel strategy for anti-aging interventions?

GATA transcription factors (TFs) constitute a conserved family of zinc-finger TFs that fulfill diverse functions across eukaryotes. Accumulating evidence suggests that GATA TFs also play a role in lifespan regulation. In a recent study, we identified a natural polyphenol, 4,4’-dimethoxychalcone (DMC), that extends lifespan depending on reduced activity of distinct GATA TFs. Prolonged lifespan by DMC treatment depends on autophagy, a protective cellular self-cleansing mechanism. In yeast, DMC reduces the activity of the GATA TF Gln3 and, genetic deletion of Gln3 is sufficient to increase autophagy levels during cellular aging. In addition, we observed similar changes in the abundance of several amino acids in the metabolome of DMC-treated and GATA/Gln3 depleted cells. Here, we examine current data on the involvement of GATA TFs in the regulation of autophagy and longevity in different organisms and explore if GATA TFs might be suitable targets for anti-aging interventions

Targeting GATA transcription factors – a novel strategy for anti-aging interventions?

GATA transcription factors (TFs) constitute a conserved family of zinc-finger TFs that fulfill diverse functions across eukaryotes. Accumulating evidence suggests that GATA TFs also play a role in lifespan regulation. In a recent study, we identified a natural polyphenol, 4,4’-dimethoxychalcone (DMC), that extends lifespan depending on reduced activity of distinct GATA TFs. Prolonged lifespan by DMC treatment depends on autophagy, a protective cellular self-cleansing mechanism. In yeast, DMC reduces the activity of the GATA TF Gln3 and, genetic deletion of Gln3 is sufficient to increase autophagy levels during cellular aging. In addition, we observed similar changes in the abundance of several amino acids in the metabolome of DMC-treated and GATA/Gln3 depleted cells. Here, we examine current data on the involvement of GATA TFs in the regulation of autophagy and longevity in different organisms and explore if GATA TFs might be suitable targets for anti-aging interventions

4,4’Dimethoxychalcone: a natural flavonoid that promotes health through autophagy-dependent and -independent effects

The age-induced deterioration of the organism results in detrimental and ultimately lethal pathologies. The process of aging itself involves a plethora of different mechanisms that should be subverted concurrently to delay and/or prevent age- related maladies. We have identified a natural compound, 4,4ʹ-dimethoxychalcone (DMC), which promotes longevity in yeast, worms and flies, and protects mice from heart injury and liver toxicity. Interestingly, both the DMC-mediated lifespan extension and the cardioprotection depend on macroautophagy/autophagy whereas hepatoprotection does not. DMC induces autophagy by inhibiting specific GATA transcription factors (TFs), independently of the TORC1 kinase pathway. The autophagy-independent beneficial effects of DMC might involve its antioxidative properties. DMC treatment results in a phylogenetically conserved, systemic impact on the metabolome, which is most prominently characterized by changes in cellular amino acid composition. Altogether, DMC exerts multiple, geroprotective effects by igniting distinct pathways, and thus represents a potential pharmacological agent that delays aging through multipronged effects

Guidelines and Recommendations on Yeast Cell Death Nomenclature

Elucidating the biology of yeast in its full complexity has major implications for science, medicine and industry. One of the most critical processes determining yeast life and physiology is cellular demise. However, the investigation of yeast cell death is a relatively young field, and a widely accepted set of concepts and terms is still missing. Here, we propose unified criteria for the definition of accidental, regulated, and programmed forms of cell death in yeast based on a series of morphological and biochemical criteria. Specifically, we provide consensus guidelines on the differential definition of terms including apoptosis, regulated necrosis, and autophagic cell death, as we refer to additional cell death routines that are relevant for the biology of (at least some species of) yeast. As this area of investigation advances rapidly, changes and extensions to this set of recommendations will be implemented in the years to come. Nonetheless, we strongly encourage the authors, reviewers and editors of scientific articles to adopt these collective standards in order to establish an accurate framework for yeast cell death research and, ultimately, to accelerate the progress of this vibrant field of research

The flavonoid 4,4′-dimethoxychalcone promotes autophagy-dependent longevity across species

Ageing constitutes the most important risk factor for all major chronic ailments, including malignant, cardiovascular and neurodegenerative diseases. However, behavioural and pharmacological interventions with feasible potential to promote health upon ageing remain rare. Here we report the identification of the flavonoid 4,4′- dimethoxychalcone (DMC) as a natural compound with anti-ageing properties. External DMC administration extends the lifespan of yeast, worms and flies, decelerates senescence of human cell cultures, and protects mice from prolonged myocardial ischaemia. Concomitantly, DMC induces autophagy, which is essential for its cytoprotective effects from yeast to mice. This pro-autophagic response induces a conserved systemic change in metabolism, operates independently of TORC1 signalling and depends on specific GATA transcription factors. Notably, we identify DMC in the plant Angelica keiskei koidzumi, to which longevity- and health-promoting effects are ascribed in Asian traditional medicine. In summary, we have identified and mechanistically characterised the conserved longevity-promoting effects of a natural anti-ageing drug

Guidelines and recommendations on yeast cell death nomenclature

Elucidating the biology of yeast in its full complexity has major implications for science, medicine and industry. One of the most critical processes determining yeast life and physiology is cel-lular demise. However, the investigation of yeast cell death is a relatively young field, and a widely accepted set of concepts and terms is still missing. Here, we propose unified criteria for the defi-nition of accidental, regulated, and programmed forms of cell death in yeast based on a series of morphological and biochemical criteria. Specifically, we provide consensus guidelines on the differ-ential definition of terms including apoptosis, regulated necrosis, and autophagic cell death, as we refer to additional cell death rou-tines that are relevant for the biology of (at least some species of) yeast. As this area of investigation advances rapidly, changes and extensions to this set of recommendations will be implemented in the years to come. Nonetheless, we strongly encourage the au-thors, reviewers and editors of scientific articles to adopt these collective standards in order to establish an accurate framework for yeast cell death research and, ultimately, to accelerate the pro-gress of this vibrant field of research