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1. 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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2. Using heat plumes to simulate post-fire effects on cambial viability and hydraulic performance in Sequoia sempervirens stems

   https://doi.org/10.1093/treephys/tpad006  

   Salladay, Ryan A. ; Pittermann, Jarmila ; Martinez-Vilalta, ed., Jordi ( January 2023 , Tree Physiology)

   Injury to the xylem and vascular cambium is proposed to explain mortality following low severity fires. These tissues have been assessed independently, but the relative significance of the xylem and cambium is still uncertain. The goal of this study is to evaluate the xylem dysfunction hypothesis and cambium necrosis hypothesis simultaneously. The hot dry conditions of a low severity fire were simulated in a drying oven, exposing Sequoia sempervirens (Lamb. ex D. Don) shoots to 70 and 100 °C for 6–60 min. Cambial viability was measured with Neutral Red stain and water transport capacity was assessed by calculating the loss of hydraulic conductivity. Vulnerability curves were also constructed to determine susceptibility to drought-induced embolism following heat exposure. The vascular cambium died completely at 100 °C after only 6 min of heat exposure, while cells remained viable at 70 °C temperatures for up to 15 min. Sixty minutes of exposure to 70 °C reduced stem hydraulic conductivity by 40%, while 45 min at 100 °C caused complete loss of conductivity. The heat treatments dropped hydraulic conductivity irrecoverably but did not significantly impact post-fire vulnerability to embolism. Overall, the damaging effects of high temperature occurred more rapidly in the vascular cambium than xylem following heat exposure. Importantly, the xylem remained functional until the most extreme treatments, long after the vascular cambium had died. Our results suggest that the viability of the vascular cambium may be more critical to post-fire survival than xylem function in S. sempervirens. Given the complexity of fire, we recommend ground-truthing the cambial and xylem post-fire response on a diverse range of species.

    

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3. Novel methods to establish whole-body primary cell cultures for the cnidarians Nematostella vectensis and Pocillopora damicornis

   https://doi.org/10.1038/s41598-021-83549-7  

   Nowotny, James D. ; Connelly, Michael T. ; Traylor-Knowles, Nikki ( December 2021 , Scientific Reports)

   Abstract Cnidarians are emerging model organisms for cell and molecular biology research. However, successful cell culture development has been challenging due to incomplete tissue dissociation and contamination. In this report, we developed and tested several different methodologies to culture primary cells from all tissues of two species of Cnidaria: Nematostella vectensis and Pocillopora damicornis . In over 170 replicated cell cultures, we demonstrate that physical dissociation was the most successful method for viable and diverse N. vectensis cells while antibiotic-assisted dissociation was most successful for viable and diverse P. damicornis cells. We also demonstrate that a rigorous antibiotic pretreatment results in less initial contamination in cell cultures. Primary cultures of both species averaged 12–13 days of viability, showed proliferation, and maintained high cell diversity including cnidocytes, nematosomes, putative gastrodermal, and epidermal cells. Overall, this work will contribute a needed tool for furthering functional cell biology experiments in Cnidaria. 

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4. An artificial host system enables the obligate parasite Cuscuta campestris to grow and reproduce in vitro

   https://doi.org/10.1093/plphys/kiac106  

   Bernal-Galeano, Vivian ; Beard, Keely ; Westwood, James H ( March 2022 , Plant Physiology)

   Abstract Cuscuta campestris is an obligate parasitic plant that requires a host to complete its life cycle. Parasite–host connections occur via a haustorium, a unique organ that acts as a bridge for the uptake of water, nutrients, and macromolecules. Research on Cuscuta is often complicated by host influences, but comparable systems for growing the parasite in the absence of a host do not exist. We developed an axenic method to grow C. campestris on an artificial host system (AHS). We evaluated the effects of nutrients and phytohormones on parasite haustoria development and growth. Haustorium morphology and gene expression were also characterized. The AHS consists of an inert, fibrous stick that mimics a host stem, wicking water and nutrients to the parasite. It enables C. campestris to exhibit a parasitic habit and develop through all stages of its life cycle, including production of new shoots and viable seeds. The phytohormones 1-naphthaleneacetic acid and 6-benzylaminopurine affect haustoria morphology and increase parasite fresh weight and biomass. Unigene expression in AHS haustoria reflects processes similar to those in haustoria on living host plants. The AHS is a methodological improvement for studying Cuscuta biology by avoiding specific host effects on the parasite and giving researchers full control of the parasite environment. 

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5. Insulin production from hiPSC‐derived pancreatic cells in a novel wicking matrix bioreactor

   https://doi.org/10.1002/bit.27359  

   Amini, Nooshin ; Paluh, Janet L. ; Xie, Yubing ; Saxena, Vinit ; Sharfstein, Susan T. ( May 2020 , Biotechnology and Bioengineering)

   Clinical use of pancreatic β islets for regenerative medicine applications requires mass production of functional cells. Current technologies are insufficient for large‐scale production in a cost‐efficient manner. Here, we evaluate advantages of a porous cellulose scaffold and demonstrate scale‐up to a wicking matrix bioreactor as a platform for culture of human endocrine cells. Scaffold modifications were evaluated in a multiwell platform to find the optimum surface condition for pancreatic cell expansion followed by bioreactor culture to confirm suitability. Preceding scale‐up, cell morphology, viability, and proliferation of primary pancreatic cells were evaluated. Two optimal surface modifications were chosen and evaluated further for insulin secretion, cell morphology, and viable cell density for human‐induced pluripotent stem cell‐derived pancreatic cells at different stages of differentiation. Scale‐up was accomplished with uncoated, amine‐modified cellulose in a miniature bioreactor, and insulin secretion and cell metabolic profiles were determined for 13 days. We achieved 10‐fold cell expansion in the bioreactor along with a significant increase in insulin secretion compared with cultures on tissue culture plastic. Our findings define a new method for expansion of pancreatic cells a on wicking matrix cellulose platform to advance cell therapy biomanufacturing for diabetes.

    

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