The conjugating green alga Zygnema sp. (Zygnematophyceae) from the Arctic shows high frost tolerance in mature cells (pre-akinetes)

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11310%2F19%3A10410525" target="_blank" >RIV/00216208:11310/19:10410525 - isvavai.cz</a>

Výsledek na webu

<a href="https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=WLTTfs0e.U" target="_blank" >https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=WLTTfs0e.U</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1007/s00709-019-01404-z" target="_blank" >10.1007/s00709-019-01404-z</a>

Jazyk výsledku

angličtina

Název v původním jazyce

The conjugating green alga Zygnema sp. (Zygnematophyceae) from the Arctic shows high frost tolerance in mature cells (pre-akinetes)

Popis výsledku v původním jazyce

Green algae of the genus Zygnema form extensive mats and produce large amounts of biomass in shallow freshwater habitats. Environmental stresses including freezing may perturb these mats, which usually have only annual character. To estimate the limits of survival at subzero temperatures, freezing resistance of young Zygnema sp. (strain MP2011 Skan) cells and pre-akinetes was investigated. Young, 2-week-old cultures were exposed to temperatures of 0 to -14 degrees C at 2-K steps, whereas 8-month-old cultures were frozen from -10 to -70 degrees C at 10-K intervals. Cell viability after freezing was determined by 0.1% auramine O vital fluorescence staining and measurements of the effective quantum yield of photosystem II (Phi(PSII)). At -8 degrees C, the young vegetative cells were unable to recover from severe frost damage. But temperatures even slightly below zero (- 2 degrees C) negatively affected the cells&apos; physiology. Single pre-akinetes could survive even at -70 degrees C, but their LT50 value was -26.2 degrees C. Severe freezing cytorrhysis was observed via cryo-microscopy at - 10 degrees C, a temperature found to be lethal for young cells. The ultrastructure of young cells appeared unchanged at -2 degrees C, but severe damage to biomembranes and formation of small foamy vacuoles was observed at -10 degrees C. Pre-akinetes did not show ultrastructural changes at - 20 degrees C; however, vacuolization increased, and gas bubbles appeared at -70 degrees C. Our results demonstrate that the formation of pre-akinetes increases freezing resistance. This adaptation is crucial for surviving the harsh temperature conditions prevailing in the High Arctic in winter and a key feature in seasonal dynamics of Zygnema sp.

Název v anglickém jazyce

The conjugating green alga Zygnema sp. (Zygnematophyceae) from the Arctic shows high frost tolerance in mature cells (pre-akinetes)

Popis výsledku anglicky

Green algae of the genus Zygnema form extensive mats and produce large amounts of biomass in shallow freshwater habitats. Environmental stresses including freezing may perturb these mats, which usually have only annual character. To estimate the limits of survival at subzero temperatures, freezing resistance of young Zygnema sp. (strain MP2011 Skan) cells and pre-akinetes was investigated. Young, 2-week-old cultures were exposed to temperatures of 0 to -14 degrees C at 2-K steps, whereas 8-month-old cultures were frozen from -10 to -70 degrees C at 10-K intervals. Cell viability after freezing was determined by 0.1% auramine O vital fluorescence staining and measurements of the effective quantum yield of photosystem II (Phi(PSII)). At -8 degrees C, the young vegetative cells were unable to recover from severe frost damage. But temperatures even slightly below zero (- 2 degrees C) negatively affected the cells&apos; physiology. Single pre-akinetes could survive even at -70 degrees C, but their LT50 value was -26.2 degrees C. Severe freezing cytorrhysis was observed via cryo-microscopy at - 10 degrees C, a temperature found to be lethal for young cells. The ultrastructure of young cells appeared unchanged at -2 degrees C, but severe damage to biomembranes and formation of small foamy vacuoles was observed at -10 degrees C. Pre-akinetes did not show ultrastructural changes at - 20 degrees C; however, vacuolization increased, and gas bubbles appeared at -70 degrees C. Our results demonstrate that the formation of pre-akinetes increases freezing resistance. This adaptation is crucial for surviving the harsh temperature conditions prevailing in the High Arctic in winter and a key feature in seasonal dynamics of Zygnema sp.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10611 - Plant sciences, botany

Projekt

<a href="/cs/project/GF15-34645L" target="_blank" >GF15-34645L: Kolonizace souše spájivými zelenými řasami</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2019

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Protoplasma

ISSN

0033-183X

e-ISSN

—

Svazek periodika

256

Číslo periodika v rámci svazku

6

Stát vydavatele periodika

AT - Rakouská republika

Počet stran výsledku

14

Strana od-do

1681-1694

Kód UT WoS článku

000500030400018

EID výsledku v databázi Scopus

2-s2.0-85069517326