Smithsonian Research Online
DSpace is a digital service that collects, preserves, and distributes digital material. Repositories are important tools for preserving an organization's legacy; they facilitate digital preservation and scholarly communication.
results
Discover
Communities in DSpace
Select a community to browse its collections.
- Anacostia Community Museum staff publications
- Art Vertical Files
Recent Submissions
Shell Damage Patterns in Limpkin Mussel Middens at Bois d’Arc Lake, Arkansas
(2024) Graves, Gary R.
The Limpkin (Aramus guarauna) is rapidly colonizing the lower Mississippi Valley from recently established Gulf Coast populations. Anecdotal reports indicate that it feeds on freshwater mussels and gastropods in Arkansas, but without documentation. Here I report an analysis of Limpkin shell middens from Bois d’Arc Lake in Hempstead Co. Limpkins at this location preyed heavily on Pyganodon grandis (Giant Floater), a large mussel species widely distributed in the Mississippi Valley. Limpkins employ vigorous bill blows to pierce holes in mussels and usually attack the anterior end of the shell. Video and photographs of feeding birds provide new insight on the mechanics of shell opening and tissue extraction. Given the distribution and current populations of mussels in Arkansas, Limpkins have the potential to become regular summer residents in the mussel-rich areas of the state.
Evaluating tissue concentrations in Panamanian golden frogs (Atelopus zeteki) infected with Batrachochytrium dendrobatidis following single 0.01% Intraconazole immersion treatment: a thesis
(2025) Frum, Alana
Chytridiomycosis, caused by Batrachochytrium dendrobatidis (Bd), continues to threaten amphibian biodiversity globally. The Panamanian golden frog (Atelopus zeteki), a species highly susceptible to Bd infection, remains extinct in the wild and dependent on ex situ conservation for survival. Itraconazole, a triazole antifungal, is widely used to treat Bd infections, yet the impact of Bd infection on itraconazole tissue absorption, distribution, and clearance in amphibians is still poorly understood. This study evaluated itraconazole tissue concentrations in Bd-infected (Bd⁺) and uninfected (Bd⁻) A. zeteki following a single 0.01% 10-minute immersion. Tissue samples were analyzed at 24, 48, 72, 144, 192, and 240 hours post-treatment, and itraconazole concentrations were measured in the skin, liver, kidney, and gastrointestinal tract using high-performance liquid chromatography (HPLC). Bd⁺ frogs exhibited consistently lower tissue concentrations and more rapid clearance compared to Bd⁻ frogs, likely due to Bd-induced physiological alterations. Tissue concentrations remained above the limit of quantification (LOQ; 0.1 ng/mg) at 240 hours in most tissues of Bd⁻ frogs but fell below the LOQ in most tissues of Bd⁺ frogs by 144–192 hours. These findings suggest that infection status influences itraconazole tissue absorption, distribution, and clearance, supporting the potential for reducing dosing frequency in Bd treatment protocols. Future treatment protocols should consider infection status, tissue-specific distribution, and optimized dosing intervals to improve efficacy and minimize adverse effects in amphibian chytridiomycosis management.
Smithsonian Libraries and Archives Annual Report 2024
(2025) Smithsonian Libraries and Archives
Phylogeny, biogeography, reticulation, and classification of Agrostis (Poaceae: Pooideae: Poeae: Agrostidinae) with expansion of Polypogon to include Lachnagrostis (in part)
(2025) Peterson, Paul M.; Soreng, Robert J.; Romaschenko, Konstantin; Barberá, Patricia; Quintanar, Alejandro; Aedo, Carlos; Saarela, Jeffery M.
To investigate the evolutionary relationships and biogeographical history among the species of Agrostis and allied genera within the subtribe Agrostidinae, we generated a phylogeny based on sequences from nuclear ribosomal DNA (ITS) and three plastid regions ( rpl32‐trnL spacer, rps16‐trnK spacer, and rps16 intron). We also aimed to assess the generic limits of Agrostis , characterize possible subgeneric relationships among species in the genus, identify hypothesized reticulation events, and present our biogeographical theory. Based on our phylogeny of 198 samples, representing 138 species (82 from Agrostis as currently recognized, 10 from Polypogon , and 10 from Lachnagrostis ), we identify two strongly supported clades within Agrostis : clade Longipaleata ( Agrostis subg. Vilfa ) and clade Brevipaleata ( A . subg. Agrostis ). The species of Agrostis in clade Longipaleata usually have florets with paleas 2/5 to as long as the lemma, whereas species in clade Brevipaleata have florets with paleas less than 2/5 as long as the lemma, minute, or absent. Core (species with congruent alignment using ITS and plastid data) phylogenetic analysis of Agrostis reveals three strongly supported clades within Longipaleata (European‐Northwest African, Asian, and African), three strongly supported clades within Brevipaleata (Asian, North American, and South American), and a European grade leading to the latter two. Of the six genera commonly associated with Agrostis , that is, Bromidium , Polypogon, Lachnagrostis, Linkagrostis, Chaetopogon, and Chaetotropis , only Polypogon maintained its status as a separate genus, while the remaining genera are subsumed within Agrostis or Polypogon . Polypogon is identified as an intergeneric hybrid originating via ancient hybridization between unknown representatives of Agrostis clade Longipaleata (plastid DNA) and Calamagrostis clade Americana (nrDNA). We include several species of Lachnagrostis , including the type ( L. filiformis ), that follow the same pattern in Polypogon , while the remaining species of Lachnagrostis in our study are identified as ancient intersubgeneric hybrids within Agrostis . We propose nine new combinations in Polypogon : P. adamsonii (Vickery) P.M. Peterson, Soreng & Romasch.; P. aemulus (R. Br.) P.M. Peterson, Soreng & Romasch.; P. billardierei (R. Br.) P.M. Peterson, Soreng & Romasch.; P. bourgaei (E. Fourn.) P.M. Peterson, Soreng & Romasch.; P. filiformis (G. Forst.) P.M. Peterson, Soreng & Romasch.; P. littoralis P.M. Peterson, Soreng & Romasch.; P. exaratus (Trin.) P.M. Peterson, Soreng & Romasch.; P. polypogonoides (Stapf) P.M. Peterson, Soreng & Romasch.; and P. reuteri (Boiss.) P.M. Peterson, Soreng & Romasch. We designate lectotypes for the names Agrostis sect. Aristatae Willd., Agrostis barbuligera Stapf, A. bourgaei E. Fourn., A. eriantha Hack., A. exarata Trin., A. lachnantha Nees, A. polypogonoides Stapf, Chaetotropis chilensis Kunth, Polypogon elongatus Kunth, P. inaequalis Trin., P. suspicatus Willd., and Vilfa muricata J. Presl .
The axillary lymphoid organ is an external, experimentally accessible immune organ in the zebrafish
(2025) Castranova, Daniel; Kenton, Madeleine I.; Kraus, Aurora; Dell, Christopher W.; Park, Jong S.; Venero Galanternik, Marina; Park, Gilseung; Lumbantobing, Daniel N.; Dye, Louis; Marvel, Miranda; Iben, James; Taimatsu, Kiyohito; Pham, Van; Willms, Reegan J.; Blevens, Lucas; Robertson, Tanner F.; Hou, Yiran; Huttenlocher, Anna; Foley, Edan; Parenti, Lynne R.; Frazer, J. K.; Narayan, Kedar; Weinstein, Brant M.
Lymph nodes and other secondary lymphoid organs play critical roles in immune surveillance and immune activation in mammals, but the deep internal locations of these organs make it challenging to image and study them in living animals. Here, we describe a previously uncharacterized external immune organ in the zebrafish ideally suited for studying immune cell dynamics in vivo, the axillary lymphoid organ (ALO). This small, translucent organ has an outer cortex teeming with immune cells, an inner medulla with a mesh-like network of fibroblastic reticular cells along which immune cells migrate, and a network of lymphatic vessels draining to a large adjacent lymph sac. Noninvasive high-resolution imaging of transgenically marked immune cells can be carried out in ALOs of living animals, which are readily accessible to external treatment. This newly discovered tissue provides a superb model for dynamic live imaging of immune cells and their interaction with pathogens and surrounding tissues, including blood and lymphatic vessels.