Publications by authors named "Nelsen M"

Ants are abundant, diverse, and occupy nearly all habitats and regions of the world. Previous work has demonstrated that ant diversification coincided with the rise of the angiosperms, and that several plant traits evolved as ants began to expand their nesting and foraging habits. In this study, we investigate whether associations with plants enabled niche expansion and are linked to climatic niche evolution in ants.

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There is a looming environmental crisis characterized by widespread declines in global biodiversity, coupled with the establishment of introduced species at accelerated rates. We quantified how multi-species invasions affect litter ant communities in natural ecosystems by leveraging museum records and contemporary collections to assemble a large (18,990 occurrences, 6,483 sampled local communities, and 177 species) 54-year (1965-2019) dataset for the entire state of Florida, USA. Nine of ten species that decreased most strongly in relative abundance ("losers") were native, while nine of the top ten "winners" were introduced species.

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Tropical regions harbor a substantial diversity of lichenized fungi, but face numerous threats to their persistence, often even before previously unknown species have been described and their evolutionary relationships have been elucidated. (Ramalinaceae) is a lichen-forming genus of fungi that produces crustose thalli, and includes a number of lineages occupying tropical rain forests; however, taxonomic and phylogenetic work on this clade is limited. Here we leverage both morphological and sequence data to describe a new species from the tropics, .

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Premise: The long-term potential for acclimation by lichens to changing climates is poorly known, despite their prominent roles in forested ecosystems. Although often considered "extremophiles," lichens may not readily acclimate to novel climates well beyond historical norms. In a previous study (Smith et al.

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Evolution of high-productivity angiosperms has been regarded as a driver of Mesozoic ecosystem restructuring. However, terrestrial productivity is limited by availability of rock-derived nutrients such as phosphorus for which permanent increases in weathering would violate mass balance requirements of the long-term carbon cycle. The potential reality of productivity increases sustained since the Mesozoic is supported here with documentation of a dramatic increase in the evolution of nitrogen-fixing or nitrogen-scavenging symbioses, including more than 100 lineages of ectomycorrhizal and lichen-forming fungi and plants with specialized microbial associations.

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Lichen associations are overwhelmingly supported by carbon produced by photosynthetic algal symbionts. These algae have diversified to occupy nearly all climates and continents; however, we have a limited understanding of how their climatic niches have evolved through time. Here we extend previous work and ask whether phylogenetic signal in, and the evolution of, climatic niche, varies across climatic variables, phylogenetic scales, and among algal lineages in the most common genus of lichen-forming algae.

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The rapidly spreading COVID-19 pandemic demanded immediate organizational pivots in departments of laboratory medicine and pathology, including development and implementation of severe acute respiratory syndrome coronavirus 2 diagnostics in the face of unprecedented supply chain shortages. Laboratory medicine and pathology educational programs were affected in numerous ways. Here, we overview the effects of COVID-19 on the large, academic Department of Laboratory Medicine and Pathology educational practice at Mayo Clinic, highlighting lessons learned for the post-pandemic era and planning for the possibility of a future pandemic.

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Article Synopsis
  • Lichens are special because they’re made of both fungi and algae working together, and the algae part, called Trebouxia, is super important but not fully understood!
  • Researchers studied data from 20 years to see how Trebouxia changed in different climates and found that it mostly likes moderate weather and then started growing in both wet and dry places!
  • They discovered that Trebouxia adapted to various habitats over time, showing that it can thrive in many environments around the world!
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Historic and modern efforts to understand lichen diversity and evolution have overwhelmingly concentrated on that of the fungal partner, which represents one of the most taxonomically diverse nutritional modes among the Fungi. But what about the algal and cyanobacterial symbionts? An explosion of studies on these cryptic symbionts over the past 20+ years has facilitated a richer understanding of their diversity, patterns of association, and the symbiosis itself. In a From the Cover article in this issue of Molecular Ecology, Dal Forno et al.

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Objective: To determine the extent to which estimates of sample and effect size in stroke rehabilitation trials can be affected by simple summation of ordinal Upper Extremity Fugl-Meyer (UEFM) items compared with a Rasch-rescaled UEFM.

Design: Rasch analysis of Interdisciplinary Comprehensive Arm Rehabilitation Evaluation (ICARE) phase III trial data, comparing 3 upper extremity (UE) motor treatments in stroke survivors enrolled 45.8±22.

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We conducted whole-genome sequencing of four inbred mouse strains initially selected for high (H1, H2) or low (L1, L2) open-field activity (OFA), and then examined strain distribution patterns for all DNA variants that differed between their BALB/cJ and C57BL/6J parental strains. Next, we assessed genome-wide sharing (3,678,826 variants) both between and within the High and Low Activity strains. Results suggested that about 10% of these DNA variants may be associated with OFA, and clearly demonstrated its polygenic nature.

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Article Synopsis
  • Symbioses, like lichens, are important in nature but we don’t fully understand how they started or why they change over time.
  • Researchers studied over 3,300 types of lichen-forming fungi to see how their relationships with other organisms evolved.
  • They found that lichenization (the process of becoming a lichen) happened differently than thought, with some types of lichens evolving from non-lichenized ancestors, which changes how we understand symbiosis overall.
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  • Sticta, a fungal genus, forms symbiotic relationships primarily with green algae or cyanobacteria, with some species having associations with both types simultaneously.
  • The study explored the diversity of green algal partners in Sticta across various global locations, revealing multiple genera of algae, with Heveochlorella being the most prevalent.
  • Geographic factors significantly influence fungal-algal partnerships in Sticta, and while fungal and algal phylogenies showed some alignment, the study found no evidence for cospeciation, indicating that other evolutionary events such as host-switching played a role in these associations.
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Article Synopsis
  • Lichens serve as effective models for studying symbiotic relationships between fungi (mycobionts) and algae (photobionts), with a focus on availability and specificity.
  • The green algal genus Trebouxia, which is a significant photobiont, shows a disparity between the number of recognized species (29) and the actual diversity, with many lineages still undescribed.
  • The study utilized DNA from over 1600 specimens to illustrate that existing classifications of Trebouxia fail to capture its full diversity, recommending a combination of genetic and morphological analyses for better taxonomy and understanding of lichen symbiosis.
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The early-successional status of lichens in modern terrestrial ecosystems, together with the role lichen-mediated weathering plays in the carbon cycle, have contributed to the long and widely held assumption that lichens occupied early terrestrial ecosystems prior to the evolution of vascular plants and drove global change during this time. Their poor preservation potential and the classification of ambiguous fossils as lichens or other fungal-algal associations have further reinforced this view. As unambiguous fossil data are lacking to demonstrate the presence of lichens prior to vascular plants, we utilize an alternate approach to assess their historic presence in early terrestrial ecosystems.

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Historical mass extinction events had major impacts on biodiversity patterns. The most recent and intensively studied event is the Cretaceous - Paleogene (K-Pg) boundary (ca. 66 million years ago [MYA]).

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Research imaging costs limit lesion-based analyses in already expensive large stroke rehabilitation trials. Despite the belief that lesion characteristics influence recovery and treatment response, prior studies have not sufficiently addressed whether lesion features are an important consideration in motor rehabilitation trial design. Using clinically-obtained neuroimaging, evaluate how lesion characteristics relate to upper extremity (UE) recovery and response to therapy in a large UE rehabilitation trial.

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Article Synopsis
  • Ant-plant interactions are important relationships where ants and plants help each other out, and scientists studied a lot of different ants and plants to understand how these interactions began.
  • They found that ants started interacting with plants a long time ago, in the Mesozoic era, when ants began to look for food in trees.
  • The study suggests that as plants became more common, ants and plants developed closer connections, but that living on plants didn't really change how ants evolved.
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The induction of tolerance to transplanted organs is a major objective in transplantation immunology research. Lymphocyte function-associated antigen-1 (LFA-1) interactions have been identified as a key component of the T-cell activation process that may be interrupted to lead to allograft tolerance. In mice, αLFA-1 mAb is a potent monotherapy that leads to the induction of donor-specific transferable tolerance.

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Background: Task-oriented therapies have been developed to address significant upper extremity disability that persists after stroke. Yet, the extent of and approach to rehabilitation and recovery remains unsatisfactory to many.

Objective: To compare a skill-directed investigational intervention with usual care treatment for body functions and structures, activities, participation, and quality of life outcomes.

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  • Multiple factors influence species distribution, including climate, dispersal ability, and geographical barriers, but fungi often defy typical biogeographic expectations seen in plants and animals.
  • A study of cosmopolitan lichen-forming fungi revealed surprising phylogeographic patterns, with distinct lineages from different geographic regions and notable sub-structuring among populations, particularly in South Africa.
  • The research indicated that while some taxa weren't monophyletic, certain Australian specimens formed a unique monophyletic group, supporting the existence of multiple candidate lineages within these fungi.
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Background: Stroke patients with mild-moderate upper extremity motor impairments and minimal sensory and cognitive deficits provide a useful model to study recovery and improve rehabilitation. Laboratory-based investigators use lesioning techniques for similar goals.

Objective: To determine whether stroke lesions in an upper extremity rehabilitation trial cohort match lesions from the preclinical stroke recovery models used to drive translational research.

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Diabetes is prevalent among solid organ transplant recipients and is universal among islet transplant recipients. Whereas diabetes is often considered to result in an immune-compromised state, the impact of chronic hyperglycemia on host alloimmunity is not clear. Potential immune-modifying effects of obesity, autoimmunity, or diabetogenic agents like streptozotocin may confound understanding alloimmunity in experimental models of diabetes.

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Several approaches successfully achieve allograft tolerance in preclinical models but are challenging to translate into clinical practice. Many clinically relevant factors can attenuate allograft tolerance induction, including intrinsic genetic resistance, peritransplant infection, inflammation, and preexisting antidonor immunity. The prevailing view for immune memory as a tolerance barrier is that the host harbors memory cells that spontaneously cross-react to donor MHC antigens.

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Foliicolous lichens are formed by diverse, highly specialized fungi that establish themselves and complete their life cycle within the brief duration of their leaf substratum. Over half of these lichen-forming fungi are members of either the Gomphillaceae or Pilocarpaceae, and associate with Trebouxia-like green algae whose identities have never been positively determined. We investigated the phylogenetic affinities of these photobionts to better understand their role in lichen establishment on an ephemeral surface.

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