Objective Adult elastic cartilage has limited repair capacity. MRL/MpJ (MRL) mice, by contrast, are capable of spontaneously healing ear punctures. This study was undertaken to characterize ...microbiome differences between healer and non-healer mice and to evaluate whether this healing phenotype can be transferred via gut microbiome transplantation. Methods We orally transplanted C57BL/6J (B6) mice with MRL/MpJ cecal contents at weaning and as adults (n = 57) and measured ear hole closure 4 weeks after a 2.0mm punch and compared to vehicle-transplanted MRL and B6 (n = 25) and B6-transplanted MRL (n = 20) mice. Sex effects, timing of transplant relative to earpunch, and transgenerational heritability were evaluated. In a subset (n = 58), cecal microbiomes were profiled by 16S sequencing and compared to ear hole closure. Microbial metagenomes were imputed using PICRUSt. Results Transplantation of B6 mice with MRL microbiota, either in weanlings or adults, improved ear hole closure. B6-vehicle mice healed ear hole punches poorly (0.25±0.03mm, mm ear hole healing 4 weeks after a 2mm ear hole punch 2.0mm-final ear hole size, mean±SEM), whereas MRL-vehicle mice healed well (1.4±0.1mm). MRL-transplanted B6 mice healed roughly three times as well as B6-vehicle mice, and half as well as MRL-vehicle mice (0.74±0.05mm, P = 6.9E-10 vs. B6-vehicle, P = 5.2E-12 vs. MRL-vehicle). Transplantation of MRL mice with B6 cecal material did not reduce MRL healing (B6-transplanted MRL 1.3±0.1 vs. MRL-vehicle 1.4±0.1, p = 0.36). Transplantation prior to ear punch was associated with the greatest ear hole closure. Offspring of transplanted mice healed significantly better than non-transplanted control mice (offspring:0.63±0.03mm, mean±SEM vs. B6-vehicle control:0.25±0.03mm, n = 39 offspring, P = 4.6E-11). Several microbiome clades were correlated with healing, including Firmicutes (R = 0.84, P = 8.0E-7), Lactobacillales (R = 0.65, P = 1.1E-3), and Verrucomicrobia (R = -0.80, P = 9.2E-6). Females of all groups tended to heal better than males (B6-vehicle P = 0.059, MRL-transplanted B6 P = 0.096, offspring of MRL-transplanted B6 P = 0.0038, B6-transplanted MRL P = 1.6E-6, MRL-vehicle P = 0.0031). Many clades characteristic of female mouse cecal microbiota vs. males were the same as clades characteristic of MRL and MRL-transplanted B6 mice vs. B6 controls, including including increases in Clostridia and reductions in Verrucomicrobia in female mice. Conclusion In this study, we found an association between the microbiome and tissue regeneration in MRL mice and demonstrate that this trait can be transferred to non-healer mice via microbiome transplantation. We identified several microbiome clades associated with healing.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abstract
National forests in the western United States are divided roughly in half between lands without roads managed for wilderness characteristics and lands with an extensive road system managed ...for multiple uses including resource extraction. We investigated the influence of these land use designations on fire ignitions, fire extent, and fire severity over the last three decades. Although roadless areas experienced fewer fire ignitions and are generally cooler, moister, and higher elevation landscapes less conducive to fire, wildfire extent was far greater in these areas than in roaded areas. An area equivalent to approximately one-third of roadless areas burned in the last three decades, while an area equivalent to less than one-fifth of roaded areas experienced fire. Most of the largest fires that have burned on national forest land in recent years began in roadless areas. Despite greater fire extent in roadless areas, there was no significant difference in fire severity between roadless areas and roaded areas after accounting for biophysical differences between these management regimes. Although fire patterns in roadless areas may pose challenges to land managers, the available evidence suggests that the greater extent of fire in roadless areas may confer resilience to these landscapes in the face of climate change.
Senescent cells are beneficial for repairing acute tissue damage, but they are harmful when they accumulate in tissues, as occurs with advancing age. Senescence-associated extracellular vesicles ...(S-EVs) can mediate cell-to-cell communication and export intracellular content to the microenvironment of aging tissues. Here, we studied the uptake of EVs from senescent cells (S-EVs) and proliferating cells (P-EVs) and found that P-EVs were readily taken up by proliferating cells (fibroblasts and cervical cancer cells) while S-EVs were not. We thus investigated the surface proteome (surfaceome) of P-EVs relative to S-EVs derived from cells that had reached senescence via replicative exhaustion, exposure to ionizing radiation, or treatment with etoposide. We found that relative to P-EVs, S-EVs from all senescence models were enriched in proteins DPP4, ANXA1, ANXA6, S10AB, AT1A1, and EPHB2. Among them, DPP4 was found to selectively prevent uptake by proliferating cells, as ectopic overexpression of DPP4 in HeLa cells rendered DPP4-expressing EVs that were no longer taken up by other proliferating cells. We propose that DPP4 on the surface of S-EVs makes these EVs refractory to internalization by proliferating cells, advancing our knowledge of the impact of senescent cells in aging-associated processes.
Ageing of rechargeable batteries is routinely characterized in the frequency domain by electrochemical impedance spectroscopy, but the technique requires laboratory measurements to be made on a time ...scale of days. However, the normal cycling of a battery as it is used in situ provides equivalent information in the time domain, though extracting robust frequency information from a time series is challenging. In this work, we explore, in the time domain, the relationship between instantaneous voltage-current phase difference and cycle efficiency. Moreover, we demonstrate that phase measures can be used to identify battery ageing. We have cycled a 250 mA h Nickel-Cobalt cell several hundred times and used Hilbert Transforms to identify phase difference between voltage and current. This phase difference becomes closer to zero as the battery ages, commensurate with a drop in energy cycle efficiency. In another experiment, we applied a synthetic current profile mimicking behaviour of an electric car cell, to a 3.2 A h LiNiMnCoO 2 cell, for ~100 days. For this more complicated profile with a wide range of frequency content, we used wavelet analysis to identify changes in phase difference and impedance as the battery aged. For this cell, drop in cycle efficiency was associated with a rise in internal resistance. The results imply that time-series analysis of in situ measurements of voltage and current, when applied with equivalent circuit models and underlying theory, can identify markers of battery ageing.
Bat flies (Hippoboscoidea: Nycteribiidae and Streblidae) are obligate hematophagous ectoparasites of bats. We collected streblid bat flies from the New World (México) and the Old World (Uganda), and ...used metagenomics to identify their viruses. In México, we found méjal virus (Rhabdoviridae; Vesiculovirus), Amate virus (Reoviridae: Orbivirus), and two unclassified viruses of invertebrates. Méjal virus is related to emerging zoonotic encephalitis viruses and to the agriculturally important vesicular stomatitis viruses (VSV). Amate virus and its sister taxon from a bat are most closely related to mosquito- and tick-borne orbiviruses, suggesting a previously unrecognized orbivirus transmission cycle involving bats and bat flies. In Uganda, we found mamucuso virus (Peribunyaviridae: Orthobunyavirus) and two unclassified viruses (a rhabdovirus and an invertebrate virus). Mamucuso virus is related to encephalitic viruses of mammals and to viruses from nycteribiid bat flies and louse flies, suggesting a previously unrecognized orthobunyavirus transmission cycle involving hippoboscoid insects. Bat fly virus transmission may be neither strictly vector-borne nor strictly vertical, with opportunistic feeding by bat flies occasionally leading to zoonotic transmission. Many “bat-associated” viruses, which are ecologically and epidemiologically associated with bats but rarely or never found in bats themselves, may actually be viruses of bat flies or other bat ectoparasites.
The combined effects of Indigenous fire stewardship and lightning ignitions shaped historical fire regimes, landscape patterns, and available resources in many ecosystems globally. The resulting fire ...regimes created complex fire–vegetation dynamics that were further influenced by biophysical setting, disturbance history, and climate. While there is increasing recognition of Indigenous fire stewardship among western scientists and managers, the extent and purpose of cultural burning is generally absent from the landscape–fire modeling literature and our understanding of ecosystem processes and development. In collaboration with the Karuk Tribe Department of Natural Resources, we developed a transdisciplinary Monte Carlo simulation model of cultural ignition location, frequency, and timing to simulate spatially explicit cultural ignitions across a 264,399‐ha landscape within Karuk Aboriginal Territory in northern California. Estimates of cultural ignition parameters were developed with Tribal members and knowledge holders using existing interviews, historical maps, ethnographies, recent ecological studies, contemporary maps, and generational knowledge. Spatial and temporal attributes of cultural burning were explicitly tied to the ecology of specific cultural resources, fuel receptivity, seasonal movement patterns, and spiritual practices. Prior to colonization, cultural burning practices were extensive across the study landscape with an estimated 6972 annual ignitions, averaging approximately 6.5 ignitions per Indigenous fire steward per year. The ignition characteristics we document align closely with data on historical fire regimes and vegetation but differ substantially from the location and timing of contemporary ignitions. This work demonstrates the importance of cultural burning for developing and maintaining the ecosystems present at the time of colonization and underscores the need to work collaboratively with Indigenous communities to restore ecocultural processes in these systems.
•Peak fine woody fuel loadings occurred 17–18year post-fire in unmanipulated stands.•Salvage logging increased fine fuel loadings 160–237% for 18–22years post-fire.•Maximum 1000-h fuel loadings ...occurred 24–31years post-fire in unmanipulated stands.•Decomposition reduced loadings by 35–50% of initial snag necromass by peak years.•Salvage logging significantly reduced 1000-h fuel loadings after 7years post-fire.
Salvage logging has been proposed to reduce post-fire hazardous fuels and mitigate re-burn effects, but debate remains about its effectiveness when considering fuel loadings are dynamic, and re-burn occurrence is stochastic, in time. Therefore, evaluating salvage loggings capacity to reduce hazardous fuels requires estimating fuel loadings in unmanipulated and salvaged stands over long time periods. We sampled for snag dynamics, decomposition rates, and fuel loadings within unmanipulated high-severity portions of 7 fires, spanning a 24-year chronosequence, in dry-mixed conifer forests of Oregon’s eastern Cascades. We used these estimates to program an empirical model predicting temporal dynamics of fine and coarse woody fuels from sources directly targeted by salvage logging. We simulated 1000 unmanipulated and salvage logging scenarios, with variable snag dynamic rates, for three sample plots spanning a pre-fire biomass gradient. Total surface fine woody fuel loadings peaked 17–18years post-fire (6.76–9.92Mgha−1) in unmanipulated stands; thereafter decay losses exceeded input rates and loadings decreased. Salvage logging immediately increased surface fine woody fuel loadings by 160–237% above maximum loadings observed in unmanipulated stands, and were higher during the initial 18–22years post-fire. 1000-h fuel loadings peaked 24–31years post-fire in unmanipulated stands, but decomposition reduced total loadings by 34.8–49.6% of initial snag necromass by peak years. Our simulations suggest only 59.2% (34.3Mgha−1), 47.8% (44.3Mgha−1) and 22.3% (37.6Mgha−1) of maximum 1000-h fuel loadings were available for combustion at this time. Available 1000-h fuel loadings in unmanipulated stands peaked 31, 34 and 82years post-fire but were only 35.4% (40.7Mgha−1), 30.8% (49.9Mgha−1) and 27.3% (70.5Mgha−1) of initial snag necromass. Salvage logging increased 1000-h fuel loadings for the initial 7years post-fire, but 80–84% of initial snag necromass was removed or decayed when their maximum loadings were observed 17–22years post-fire. Understory woody vegetation reestablished quickly following high-severity fire, creating another significant fuel layer and a source of post-fire fine woody fuels. Surface fuels accumulate quickly following high-severity fire, but our modeling results suggest salvage logging has mixed effects on reducing hazardous fuel conditions since it increases fine woody fuel loadings and decreases coarse woody fuel loadings. Reducing hazardous fuel loadings and their contribution to re-burn hazard requires manipulation of residual and future fuel sources, but treatment benefits should be evaluated against any negative effects to early seral forest structure and function if resilient forest ecosystems are the management goal.
► Snag fall and breakage rates are positively correlated with time since fire and DBH. ► Snag fall rates increase by species from Pinus spp. to Abies spp. to P. menziesii. ► Abies sp. snag decay at a ...rate of k=0.0179yr−1. ► P. ponderosa snags did not exhibit significant decay. ► P. ponderosa log decay rate was k=0.024yr−1 but varied by sapwood and heartwood..
Early seral forest habitats are increasingly valued for the unique structural resources they provide in many western US forests. Coarse woody detritus (CWD) are a significant feature of this developmental stage and are highly dynamic, suggesting these environments exhibit temporally diverse structural conditions prior to forest canopy closure. In dry-mixed conifer forests, snags are hypothesized to decay slower than logs making long-term dynamics in these forests dependent on snag fall, breakage and the decay rates of both standing and surface CWD. We estimated snag fall and breakage rates for Pinus ponderosa, Abies sp., P. menziesii and P. contorta snags in three diameter classes (<23cm, 23–41cm and >41cm) from 6057 snags across a 24-year chronosequence of early seral environments. Snag and log decay rates were estimated by felling 60 Abies sp. and 60 P. ponderosa snags, and sampling 40 P. ponderosa logs. Half-life estimates for snags <23cm, 23–41cm, and >41cm were 7, 12, and 17years for Pinus sp., 10, 15, and 20years for Abies sp., and 11, 17, and 23years for P. menziesii. Breakage rates were lowest for small snags and not significantly different for medium and large snags, but did vary across species. We estimated an Abies sp. snag decomposition loss-rate constant of k=0.0179yr−1 (SE=0.00533, p-value=0.0014) but P. ponderosa snags did not exhibit statistically significant decay (k=0.0024yr−1, SE=0.00518, p-value=0.6414). P. ponderosa logs had an estimated decomposition loss-rate constant of k=0.0243yr−1 (SE=0.0073, p-value=0.0023), confirming reduced decay rates in snags and variation among species. Following high-severity fire, dry-mixed conifer stands experience relatively rapid temporal changes in CWD resources largely dependent on snag species and diameter-at-breast-height (DBH). Variation in fall, breakage and decay rates among species and DBH suggests maintaining a diverse selection of snag species and diameters would meet multiple ecological needs across a broader temporal scale. Additionally, given the rapid temporal changes in CWD, defining early seral habitat as the period immediately following disturbance until canopy closure may not adequately account for the diversity in habitat structures and resources available over time.
The knowledge systems and practices of Indigenous Peoples and local communities play critical roles in safeguarding the biological and cultural diversity of our planet. Globalization, government ...policies, capitalism, colonialism, and other rapid social-ecological changes threaten the relationships between Indigenous Peoples and local communities and their environments, thereby challenging the continuity and dynamism of Indigenous and Local Knowledge (ILK). In this article, we contribute to the “World Scientists' Warning to Humanity,” issued by the Alliance of World Scientists, by exploring opportunities for sustaining ILK systems on behalf of the future stewardship of our planet. Our warning raises the alarm about the pervasive and ubiquitous erosion of knowledge and practice and the social and ecological consequences of this erosion. While ILK systems can be adaptable and resilient, the foundations of these knowledge systems are compromised by ongoing suppression, misrepresentation, appropriation, assimilation, disconnection, and destruction of biocultural heritage. Three case studies illustrate these processes and how protecting ILK is central to biocultural conservation. We conclude with 15 recommendations that call for the recognition and support of Indigenous Peoples and local communities and their knowledge systems. Enacting these recommendations will entail a transformative and sustained shift in how ILK systems, their knowledge holders, and their multiple expressions in lands and waters are recognized, affirmed, and valued. We appeal for urgent action to support the efforts of Indigenous Peoples and local communities around the world to maintain their knowledge systems, languages, stewardship rights, ties to lands and waters, and the biocultural integrity of their territories—on which we all depend.
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