Development of a new kappa-carrageenan hydrogel system to study benthic diatom vertical movements.

Benthic diatom vertical movement has been investigated mainly through indirect measurements based on chlorophyll a fluorescence and spectral reflectance signals. The presence of sediment hinders direct imaging and grazers activity renders the work under controlled conditions very difficult. This stu...

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Main Authors: Arianna Rizzo, Alessandro Ajò, Huixuan Kang, Luisa De Cola, Bruno Jesus
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2024-01-01
Series:PLoS ONE
Online Access:https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0297962&type=printable
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author Arianna Rizzo
Alessandro Ajò
Huixuan Kang
Luisa De Cola
Bruno Jesus
author_facet Arianna Rizzo
Alessandro Ajò
Huixuan Kang
Luisa De Cola
Bruno Jesus
author_sort Arianna Rizzo
collection DOAJ
description Benthic diatom vertical movement has been investigated mainly through indirect measurements based on chlorophyll a fluorescence and spectral reflectance signals. The presence of sediment hinders direct imaging and grazers activity renders the work under controlled conditions very difficult. This study provides a tool to study diatoms movement in a 3D hydrogel matrix. Synthetic and natural hydrogels were tested to find the best 3D transparent scaffold where diatoms could grow and freely move in all directions. Polyamidoamines (PAAm) hydrogels were no-cytocompatible and hyaluronic acid (HA) only allowed diatoms to survive for 2-days. Natural hydrogels made of gelatin/Na-alginate, Na-alginate and kappa-carrageenan (KC) were cytocompatible, with KC showing the best properties for diatom growth and movement on a long term (up to 2 months). Comparing Nitzschia spathulata, Gyrosigma limosum and Navicula phyllepta growth in liquid media vs in KC gels, we found that diatoms reached a significantly higher final biomass in the hydrogel condition. Hydrogels were also useful to isolate large size diatom species e.g., Nitzschia elongata, that did not survive in suspension. Finally, we showed three ways to study diatom species-specific movement in KC hydrogels: 1) controlled species mix; 2) natural diatom assemblages with grazers; and 3) natural diatom assemblages without grazers. With our system, single diatoms could be imaged, identified, and counted. In addition, different stimuli, e.g., light intensity and light composition can be applied and their effects on movement and physiology studied without being masked by sediment or impaired by meiofauna.
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spelling doaj.art-191ea4ea4515423d8dab8e98e6e98f2c2024-04-18T05:31:47ZengPublic Library of Science (PLoS)PLoS ONE1932-62032024-01-01194e029796210.1371/journal.pone.0297962Development of a new kappa-carrageenan hydrogel system to study benthic diatom vertical movements.Arianna RizzoAlessandro AjòHuixuan KangLuisa De ColaBruno JesusBenthic diatom vertical movement has been investigated mainly through indirect measurements based on chlorophyll a fluorescence and spectral reflectance signals. The presence of sediment hinders direct imaging and grazers activity renders the work under controlled conditions very difficult. This study provides a tool to study diatoms movement in a 3D hydrogel matrix. Synthetic and natural hydrogels were tested to find the best 3D transparent scaffold where diatoms could grow and freely move in all directions. Polyamidoamines (PAAm) hydrogels were no-cytocompatible and hyaluronic acid (HA) only allowed diatoms to survive for 2-days. Natural hydrogels made of gelatin/Na-alginate, Na-alginate and kappa-carrageenan (KC) were cytocompatible, with KC showing the best properties for diatom growth and movement on a long term (up to 2 months). Comparing Nitzschia spathulata, Gyrosigma limosum and Navicula phyllepta growth in liquid media vs in KC gels, we found that diatoms reached a significantly higher final biomass in the hydrogel condition. Hydrogels were also useful to isolate large size diatom species e.g., Nitzschia elongata, that did not survive in suspension. Finally, we showed three ways to study diatom species-specific movement in KC hydrogels: 1) controlled species mix; 2) natural diatom assemblages with grazers; and 3) natural diatom assemblages without grazers. With our system, single diatoms could be imaged, identified, and counted. In addition, different stimuli, e.g., light intensity and light composition can be applied and their effects on movement and physiology studied without being masked by sediment or impaired by meiofauna.https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0297962&type=printable
spellingShingle Arianna Rizzo
Alessandro Ajò
Huixuan Kang
Luisa De Cola
Bruno Jesus
Development of a new kappa-carrageenan hydrogel system to study benthic diatom vertical movements.
PLoS ONE
title Development of a new kappa-carrageenan hydrogel system to study benthic diatom vertical movements.
title_full Development of a new kappa-carrageenan hydrogel system to study benthic diatom vertical movements.
title_fullStr Development of a new kappa-carrageenan hydrogel system to study benthic diatom vertical movements.
title_full_unstemmed Development of a new kappa-carrageenan hydrogel system to study benthic diatom vertical movements.
title_short Development of a new kappa-carrageenan hydrogel system to study benthic diatom vertical movements.
title_sort development of a new kappa carrageenan hydrogel system to study benthic diatom vertical movements
url https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0297962&type=printable
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