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1. Transcriptome analyses of leaf architecture in Sansevieria support a common genetic toolkit in the parallel evolution of unifacial leaves in monocots

   https://doi.org/10.1002/pld3.511  

   Golenberg, Edward M. ; Popadić, Aleksandar ; Hao, Weilong ( August 2023 , Plant Direct)

   Planar structures dramatically increase the surface‐area‐to‐volume ratio, which is critically important for multicellular organisms. In this study, we utilize naturally occurring phenotypic variation among threeSansivieriaspecies (Asperagaceae) to investigate leaf margin expression patterns that are associated with mediolateral and adaxial/abaxial development. We identified differentially expressed genes (DEGs) between center and margin leaf tissues in two planar‐leaf speciesSansevieria subspicataandSansevieria trifasciataand compared these with expression patterns within the cylindrically leavedSansevieria cylindrica. TwoYABBYfamily genes, homologs ofFILAMENTOUS FLOWERandDROOPING LEAF, are overexpressed in the center leaf tissue in the planar‐leaf species and in the tissue of the cylindrical leaves. As mesophyll structure does not indicate adaxial versus abaxial differentiation, increased leaf thickness results in more water‐storage tissue and enhances resistance to aridity. This suggests that the cylindrical‐leaf inS. cylindricais analogous to the central leaf tissue in the planar‐leaf species. Furthermore, the congruence of the expression patterns of theseYABBYgenes inSansevieriawith expression patterns found in other unifacial monocot species suggests that patterns of parallel evolution may be the result of similar solutions derived from a limited developmental toolbox.

    

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2. Evidence of endozoochory in upland geese Chloephaga picta and white‐bellied seedsnipes Attagis malouinus in sub‐Antarctic Chile

   https://doi.org/10.1002/ece3.7725  

   Lázaro, Xenabeth A. ; Mackenzie, Roy ; Jiménez, Jaime E. ( June 2021 , Ecology and Evolution)

   Birds are known to act as potential vectors for the exogenous dispersal of bryophyte diaspores. Given the totipotency of vegetative tissue of many bryophytes, birds could also contribute to endozoochorous bryophyte dispersal. Research has shown that fecal samples of the upland goose (Chloephaga picta) and white‐bellied seedsnipe (Attagis malouinus) contain bryophyte fragments. Although few fragments from bird feces have been known to regenerate, the evidence for the viability of diaspores following passage through the bird intestinal tract remains ambiguous. We evaluated the role of endozoochory in these same herbivorous and sympatric bird species in sub‐Antarctic Chile. We hypothesized that fragments of bryophyte gametophytes retrieved from their feces are viable and capable of regenerating new plant tissue. Eleven feces disk samples containing undetermined moss fragments fromC. picta(N = 6) andA. malouinus(N = 5) and six moss fragment samples from wild‐collected mosses (Conostomumtetragonum,Syntrichiarobusta, andPolytrichumstrictum) were grown ex situ in peat soil and in vitro using a agar Gamborg medium. After 91 days, 20% of fragments fromA. malouinusfeces, 50% of fragments fromC. pictafeces, and 67% of propagules from wild mosses produced new growth. The fact that moss diaspores remained viable and can regenerate under experimental conditions following the passage through the intestinal tracts of these robust fliers and altitudinal and latitudinal migrants suggests that sub‐Antarctic birds might play a role in bryophyte dispersal. This relationship may have important implications in the way bryophytes disperse and colonize habitats facing climate change.

    

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3. Genotypic variability following fusion in the invasive colonial tunicate Didemnum vexillum

   https://doi.org/10.1111/ivb.12263  

   Weinberg, Rachel Beth ; Clancy, Darragh Lillian ; Cohen, C. Sarah ( September 2019 , Invertebrate Biology)

   Fusion to form a chimera has been documented in many marine invertebrate taxa, including poriferans, cnidarians, bryozoans, and colonial ascidians. Allogenic interactions in chimeric ascidian colonies vary widely across taxonomic groups but are poorly characterized in the invasive colonial ascidianDidemnum vexillum.The moderate level of discrimination expressed in the fusion–rejection response ofD. vexillumsuggests that there is some integration of cells beyond the fusion line in a chimeric colony. We tracked the shifts in representation of microsatellite alleles between fused colonies ofD. vexillumto elucidate the extent of genotypic integration in fused colonies and the patterns of changes to the genotypic composition of colonies immediately following chimera formation. By genotyping colonies before and after fusion, we found that allogeneic fusion inD. vexillummay lead to genotypic changes beyond the visible fusion line. Alleles from one colony were found in multiple tissue samples in the chimera 7–10 days after fusion had occurred. In some instances, alleles that were in a single colony prior to fusion were lost following fusion. We observed multiple patterns of allelic change, including both the unidirectional transfer and reciprocal exchange of alleles between fused colonies. Our findings suggest that tissue or cells are exchanged following allogeneic fusion between colonies ofD. vexillumand that the genotypic composition of chimeric colonies may be fluid.

    

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4. Benthic cyanobacteria of the genus Nostoc are a source of microcystins in Greenlandic lakes and ponds

   https://doi.org/10.1111/fwb.13636  

   Trout‐Haney, Jessica V. ; Ritger, Amelia L. ; Cottingham, Kathryn L. ( October 2020 , Freshwater Biology)

   Benthic primary producers are recognised for their important role in contributing to ecosystem productivity and nutrient cycling in lake and stream ecosystems, particularly in polar environments. In Arctic lakes, benthic producers often comprise mats or colonies of cyanobacteria capable of producing cyanotoxins. However, the extent to which benthic communities contribute cyanotoxins in polar regions remains poorly described.

   We evaluated the potential for benthic colonies of the cyanobacteriumNostoc pruniformefrom lakes in Kangerlussuaq, Greenland, to contribute microcystins (MCs) to lake water using three approaches. First, we dissected field‐collectedNostoccolonies and measured MCs within multiple layers of fresh colony tissue. Second, we conducted a laboratory experiment to evaluate the temporal dynamics of MC release by incubated, intact colonies. Finally, we quantified whether MC concentrations in water and sediment samples in the field were higher in and above dense bands of benthicNostocas compared to bare sediment.

   Field‐collectedNostoccolonies contained MCs throughout the colony tissue, suggesting that damage to colonies from grazers or physical disturbance could facilitate the release of toxins into the water. UndamagedNostoccolonies incubated in high‐nutrient conditions in the laboratory leaked MCs into the surrounding water at a steady mass‐specific rate over the course of 7 days.

   Microcystin concentrations in water and sediment from two Greenlandic lakes were highly variable, but slightly higher in lake water immediately above dense bands ofNostocthan in water immediately above bare sediments, suggesting that benthicNostoccolonies contribute cyanotoxins to lake water and that MCs vary at very fine, 1–2 m spatial scales.

   Benthic cyanobacteria may be important in releasing MCs into aquatic ecosystems, especially in systems where benthic producers dominate, such as polar environments.

    

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5. CYP2C19 and STAT6 Variants Influence the Outcome of Proton Pump Inhibitor Therapy in Pediatric Eosinophilic Esophagitis

   https://doi.org/10.1097/MPG.0000000000002480  

   Mougey, Edward B. ; Williams, Andre ; Coyne, Ashlan J. Kunz ; Gutiérrez‐Junquera, Carolina ; Fernández‐Fernández, Sonia ; Cilleruelo, Maria Luz ; Rayo, Ana ; Echeverría, Luis ; Román, Enriqueta ; González Lois, Carmen ; et al ( November 2019 , Journal of Pediatric Gastroenterology and Nutrition)

   Proton pump inhibitors (PPIs) are an effective treatment for eosinophilic esophagitis (EoE); however, only 30% to 60% of patients respond. Common genetic variants inCYP2C19andSTAT6associate with PPI plasma concentration and magnitude of inflammatory response, respectively. Our objective was to determine if genetic variation in the genes forCYP2C19andSTAT6influence differentiation between PPI responsive esophageal eosinophilia versus PPI nonresponsive EoE (PPI‐REE, PPI‐nonresponsive EoE).

   Genomic DNA was isolated from 92 esophageal tissue biopsies collected from participants of a prospective clinical trial of high‐dose PPI therapy for esophageal eosinophilia in children.

   Of the 92 patients examined, 57 (62%) were PPI‐REE and 35 (38%) were PPI‐nonresponsive EoE. Forty‐six of the 92 patients were further characterized by pH probe monitoring; there was no association between reflux index and carriage ofCYP2C19^*17(P= 0.35). In children who received a PPI dose between ≥1.54 and ⩽2.05 mg/kg/day, binary logistic regression modeling showed that carriage ofCYP2C19^*17associated with PPI‐nonresponsive EoE (odds ratio (OR) [95% confidence interval (CI)] = 7.71 [1.21, 49.11],P= 0.031). Carriage ofSTAT6allelic variant rs1059513 predicts PPI‐REE (OR [95% CI] = 6.16 [1.44, 26.4],P= 0.028), whereas carriage ofSTAT6rs324011 synergizes withCYP2C19^*17to predict PPI‐nonresponsive EoE (rs324011 OR [95% CI] = 5.56 [1.33, 20.72],P= 0.022;CYP2C19^*17OR [95% CI] = 8.19[1.42, 50.57],P= 0.023).

   Common variants inCYP2C19andSTAT6associate with a PPI‐nonresponsive EoE outcome of PPI therapy for esophageal eosinophilia suggesting that response rates may be improved by adopting a genotype‐guided approach to PPI dosing.

    

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