Diverse symbiont bleaching responses are evident from 2-degree heating week bleaching conditions as thermal stress intensifies in coral

2020 ◽  
Vol 71 (9) ◽  
pp. 1149 ◽  
Author(s):  
Sarah Gierz ◽  
Tracy D. Ainsworth ◽  
William Leggat
Keyword(s):  
Thermal Stress ◽  
Cellular Responses ◽  
Stress Exposure ◽  
Thermal Threshold ◽  
Host Coral ◽  
Cellular Processes ◽  
Ecological Scale ◽  
Bleaching Response ◽  
Degree Heating Weeks ◽  
Host Tissues

Coral bleaching is the dysfunction of the coral–algal endosymbiosis and is characterised as a loss of Symbiodiniaceae cells from host tissues or the loss of photosynthetic pigments. This breakdown of symbiosis occurs as a result of elevated temperature beyond the organism’s thermal threshold. The thermal tipping points within the symbiosis have not yet been well resolved, and the mechanisms underlying the various cellular processes of the corals bleaching response remain unknown. This study characterised the cellular responses of the symbiont Cladocopium sp. (syn. clade C3) within the host coral Acropora aspera during exposure to thermal stress. Exposure to temperatures between 2 and 3°C below the bleaching threshold, equating to 2-degree heating weeks (DHWs), results in changes to the symbiont cell morphology and cell division rates. Once corals were exposed to 4 DHWs, over 90% of the symbiont cells showed signs of degradation. Although sub-bleaching thermal stress is not sufficient to trigger bleaching alerts at an ecological scale, this stressor substantially affects the coral symbiosis. It is therefore vital that we begin to quantify how sub-bleaching thermal stress affects the fitness of Symbiodiniacea populations, their coral hosts and subsequently reefs worldwide.

Thermal stress exposure, bleaching response, and mortality in the threatened coral Acropora palmata

2017 ◽  
Vol 124 (1) ◽  
pp. 189-197 ◽  
Author(s):  
D.E. Williams ◽  
M.W. Miller ◽  
A.J. Bright ◽  
R.E. Pausch ◽  
A. Valdivia
Keyword(s):  
Thermal Stress ◽  
Acropora Palmata ◽  
Stress Exposure ◽  
Bleaching Response

scholarly journals Interplay between ADP-ribosyltransferases and essential cell signaling pathways controls cellular responses

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Flurina Boehi ◽  
Patrick Manetsch ◽  
Michael O. Hottiger
Keyword(s):  
Cell Signaling ◽  
Signaling Pathways ◽  
Intracellular Signaling ◽  
Cellular Responses ◽  
Dynamic Regulation ◽  
Post Translational Modifications ◽  
Adp Ribosylation ◽  
Cellular Processes ◽  
Adp Ribosyltransferase ◽  
Cell Signaling Pathways

AbstractSignaling cascades provide integrative and interactive frameworks that allow the cell to respond to signals from its environment and/or from within the cell itself. The dynamic regulation of mammalian cell signaling pathways is often modulated by cascades of protein post-translational modifications (PTMs). ADP-ribosylation is a PTM that is catalyzed by ADP-ribosyltransferases and manifests as mono- (MARylation) or poly- (PARylation) ADP-ribosylation depending on the addition of one or multiple ADP-ribose units to protein substrates. ADP-ribosylation has recently emerged as an important cell regulator that impacts a plethora of cellular processes, including many intracellular signaling events. Here, we provide an overview of the interplay between the intracellular diphtheria toxin-like ADP-ribosyltransferase (ARTD) family members and five selected signaling pathways (including NF-κB, JAK/STAT, Wnt-β-catenin, MAPK, PI3K/AKT), which are frequently described to control or to be controlled by ADP-ribosyltransferases and how these interactions impact the cellular responses.

MASKING BEHAVIOUR IN A COMMENSAL SHRIMP, METAPONTONIA FUNGIACOLA BRUCE, 1967 THAT USES THE SOFT TISSUES OF THE HOST CORAL (DECAPODA, PALAEMONIDAE, PONTONIINAE)

Crustaceana ◽  
1999 ◽  
Vol 72 (3) ◽  
pp. 307-312 ◽  
Author(s):  
Hideyuki Yamashiro
Keyword(s):  
Soft Tissues ◽  
Host Coral ◽  
The Third ◽  
Tissus Mous ◽  
Host Tissues

AbstractMasking behaviour was observed in a commensal pontoniine shrimp, Metapontonia fungiacola, living on the discs of fungiid corals (Scleractinia, Fungiidae). When the coral was disturbed, the shrimp moved to and situated itself between the coral septa, and then performed masking behaviour. The shrimp thus hid itself under host tissues by "hooking" soft tissues of the coral with the dactyli of three pairs of pereiopods (i.e., the third to the fifth) in such a way, that these approached each other on the shrimp's back, like drawing curtains. Le comportement de camouflage a ete observe chez la crevette commensale Pontoniinae, Metapontonia fungiacola, vivant sur les disques de coraux Fungiidae (Scleractinia). Quand ces derniers sont inquietes, la crevette vient se placer entre les cloisons coralliaires et developpe alors son comportement de camouflage. La crevette se cache sous les tissus mous de l'hote en s'y accrochant a l'aide des dactyles de trois paires de pereiopodes (troisieme a cinquieme paire) de telle facon que lorsqu'ils se rapprochent, les tissus se referment comme si on tirait des rideaux.

scholarly journals Who's really in control: microbial regulation of protein trafficking in the epithelium

2014 ◽  
Vol 306 (3) ◽  
pp. C187-C197 ◽  
Author(s):  
Matthew R. Hendricks ◽  
Jennifer M. Bomberger
Keyword(s):  
Epithelial Cell ◽  
Protein Trafficking ◽  
Host Cells ◽  
Eukaryotic Cells ◽  
Cell Physiology ◽  
Cellular Physiology ◽  
Cellular Processes ◽  
Complex Interactions ◽  
Host Pathogen ◽  
Host Tissues

Due to evolutionary pressure, there are many complex interactions at the interface between pathogens and eukaryotic host cells wherein host cells attempt to clear invading microorganisms and pathogens counter these mechanisms to colonize and invade host tissues. One striking observation from studies focused on this interface is that pathogens have multiple mechanisms to modulate and disrupt normal cellular physiology to establish replication niches and avoid clearance. The precision by which pathogens exert their effects on host cells makes them excellent tools to answer questions about cell physiology of eukaryotic cells. Furthermore, an understanding of these mechanisms at the host-pathogen interface will benefit our understanding of how pathogens cause disease. In this review, we describe a few examples of how pathogens disrupt normal cellular physiology and protein trafficking at epithelial cell barriers to underscore how pathogens modulate cellular processes to cause disease and how this knowledge has been utilized to learn about cellular physiology.

scholarly journals Rapid auxin-mediated phosphorylation of Myosin regulates trafficking and polarity in Arabidopsis

2021 ◽  
Author(s):  
Huibin Han ◽  
Inge Verstraeten ◽  
Mark Roosjen ◽  
Ewa Mazur ◽  
Nikola Rydza ◽  
...  
Keyword(s):  
Plant Development ◽  
Auxin Transport ◽  
Adaptor Protein ◽  
Feedback Regulation ◽  
Cellular Responses ◽  
Central Component ◽  
Auxin Signaling ◽  
Auxin Response ◽  
Cellular Processes ◽  
Myosin Xi

The signaling molecule auxin controls plant development through a well-known transcriptional mechanism that regulates many genes. However, auxin also triggers cellular responses within seconds or minutes, and mechanisms mediating such fast responses have remained elusive. Here, we identified an ultrafast auxin-mediated protein phosphorylation response in Arabidopsis roots that is largely independent of the canonical TIR1/AFB receptors. Among targets of this novel response are Myosin XI and its adaptor protein MadB2. We show that their auxin-mediated phosphorylation regulates trafficking and polar, subcellular distribution of PIN auxin transporters. This phosphorylation-based auxin signaling module is indispensable during developmental processes that rely on auxin-mediated PIN repolarization, such as termination of shoot gravitropic bending or vasculature formation and regeneration. Hence, we identified a fast, non-canonical auxin response targeting multiple cellular processes and revealed auxin-triggered phosphorylation of a myosin complex as the mechanism for feedback regulation of directional auxin transport, a central component of auxin canalization, which underlies self-organizing plant development.

scholarly journals Heat Stress Regulates the Expression of TPK1 Gene at Transcriptional and Post-Transcriptional Levels in Saccharomyces cerevisiae

2021 ◽  
Author(s):  
Luciana Cañononero ◽  
Constanza Pautasso ◽  
Fiorella Galello ◽  
Lorena Sigaut ◽  
Lia Pietrasanta ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Thermal Stress ◽  
Heat Shock ◽  
Protein Kinase ◽  
Yeast Cells ◽  
Mrna Levels ◽  
Protein Levels ◽  
Cellular Processes ◽  
Polysome Profiling ◽  
Subunit Expression

In Saccharomyces cerevisiae, cAMP regulates a number of different cellular processes, such as cell growth, metabolism, stress resistance and gene transcription. The intracellular target for this second messenger in yeast cells is the cAMP-dependent protein kinase (PKA). The way in which a broad specificity protein kinase mediates one right physiological response after cAMP increase indicates that specificity is highly regulated in the cAMP / PKA system. Here we address the mechanism through which cAMP-PKA signalling mediates its response to heat shock thermotolerance in Saccharomyces cerevisiae. Yeast PKA is a tetrameric holoenzyme composed of a regulatory (Bcy1) subunit dimer and two catalytic subunits (Tpk1, Tpk2 and Tpk3). PKA subunits are differentially expressed under certain stress conditions. In the present study we show that, although the mRNA levels of TPK1 are upregulated upon heat shock at 37℃, no change is detected in Tpk1 protein levels. The half-life of TPK1 mRNA increases and this mRNA condensates in cytoplasmic foci upon thermal stress. The resistance of TPK1 mRNA foci to cycloheximide-induced disassembly, together with the polysome profiling analysis suggest that TPK1 mRNA is impaired for entry into translation. TPK1 mRNA foci and TPK1 expression were also evaluated during thermotolerance. The crosstalk of cAMP-PKA pathway and cell wall integrity (CWI) signalling was also studied. Wsc3 sensor and other components of the CWI pathway are necessary for the upregulation of TPK1 mRNA upon heat shock conditions. The assembly in cytoplasmic foci upon thermal stress shows to be dependent of Wsc3. Finally, evidence of an increase in the abundance of Tpk1 in the PKA holoenzyme in response to heat shock is presented. The results indicate the existence of a mechanism that exclusively regulates Tpk1 subunit expression, which contributes to cAMP-PKA specificity and also suggest that a recurrent stress enhanced the fitness for the coming favorable conditions.

scholarly journals Coral community bleaching response on a highly urbanised reef

2014 ◽  
Author(s):  
James R Guest ◽  
Jeffrey Low ◽  
Karenne Tun ◽  
Jani I Tanzil ◽  
Peter A Todd ◽  
...  
Keyword(s):  
Community Structure ◽  
Thermal Stress ◽  
Anthropogenic Impacts ◽  
Coral Cover ◽  
Regional Scale ◽  
Coral Community ◽  
Bleaching Response ◽  
Sea Surface Temperature Anomalies ◽  
Relative Cover ◽  
June July

Projected increases in the magnitude and frequency of sea surface temperature anomalies present a significant threat to the persistence of tropical coral reefs, however, detailed studies of community level responses to thermal stress are needed if its effect on reef resilience are to be understood. While many studies report on broad, regional scale responses to thermal stress (e.g., proportion of corals bleached), far fewer examine variation in susceptibility among taxa and change in coral community structure, before, during and after bleaching on individual reefs. Furthermore, relatively few studies of bleaching response come from highly urbanised reefs that experience chronic disturbances such as elevated sedimentation and turbidity. Here we report in detail on the bleaching response of corals at a highly urbanised reef site south of mainland Singapore during (June, July) and immediately after (October) a major thermal coral bleaching event in 2010. To estimate the capacity for resistance and resilience to thermal stress, we report on a) the overall bleaching severity during and after the event, b) differences in bleaching susceptibility among taxa during the event and c) the response of the reef in terms of taxonomic community structure before (2009) and after (2012) bleaching. Despite severe bleaching in 2010 (66% of colonies bleached), post-bleaching recovery appeared to be relatively rapid and coral taxa that are usually highly susceptible (e.g., Acropora and Pocillopora) were relatively unaffected, i.e., either they did not bleach or they bleached and recovered. Although there was no significant change in coral taxonomic community structure among years, taxa that bleached most severely tended to have the greatest reductions in relative cover. Several factors may have contributed to the overall high resistance of this site to bleaching including turbidity, symbiont affiliation and heterotrophy. A parsimonious explanation for the reversed pattern of bleaching susceptibility among taxa is that these coral populations have adapted and/or acclimatised to thermal stress. Despite ongoing chronic anthropogenic impacts, we suggest that this site has potential for rapid recovery of coral cover due to the dominant coral taxa and growth forms being capable of rapid regrowth from remnant colonies.

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