scholarly journals Higher stress and immunity responses are associated with higher mortality in reef-building coral exposed to a bacterial challenge

2016 ◽  
Author(s):  
Rachel M. Wright ◽  
Carly D. Kenkel ◽  
Carly E. Dunn ◽  
Erin N. Shilling ◽  
Line K. Bay ◽  
...  

ABSTRACTUnderstanding the drivers of intraspecific variation in susceptibility is essential to manage increasingly frequent coral disease outbreaks. We challenged replicate fragments of eight Acropora millepora genotypes with Vibrio spp. to quantify variation in lesion development and to identify host and coral-associated microbial community properties associated with resistance. While Vibrio spp. remained relatively rare in the microbiome of challenged corals, other stress-associated microbial taxa significantly increased in abundance. Contrary to expectations, higher constitutive immunity and more active immune responses did not confer higher resistance to bacterial challenge. Furthermore, more pronounced gene expression responses to bacterial challenge were associated with higher rather than lower mortality. A newly developed gene expression assay based on two genes related to inflammation and immune responses, deleted in malignant brain tumors 1 and a matrix metalloproteinase, predicted mortality under Vibrio treatment both in the initial experiment and in a validation experiment involving another 20 A. millepora genotypes. Instead of mounting more robust responses, resistant corals were largely unaffected by the bacterial challenge and maintained gene expression signatures of healthier condition, including elevated fluorescent proteins and ribosomal biosynthesis along with diminished ubiquitination. Overall, our results support the view that coral disease and mortality is commonly due to opportunistic pathogens exploiting physiologically compromised hosts rather than specific infections, and show, contrary to the prevailing wisdom, that greater immune responses do not necessarily translate into greater disease resistance.

2020 ◽  
Vol 27 (20) ◽  
pp. 3330-3345
Author(s):  
Ana G. Rodríguez-Hernández ◽  
Rafael Vazquez-Duhalt ◽  
Alejandro Huerta-Saquero

Nanomaterials have become part of our daily lives, particularly nanoparticles contained in food, water, cosmetics, additives and textiles. Nanoparticles interact with organisms at the cellular level. The cell membrane is the first protective barrier against the potential toxic effect of nanoparticles. This first contact, including the interaction between the cell membranes -and associated proteins- and the nanoparticles is critically reviewed here. Nanoparticles, depending on their toxicity, can cause cellular physiology alterations, such as a disruption in cell signaling or changes in gene expression and they can trigger immune responses and even apoptosis. Additionally, the fundamental thermodynamics behind the nanoparticle-membrane and nanoparticle-proteins-membrane interactions are discussed. The analysis is intended to increase our insight into the mechanisms involved in these interactions. Finally, consequences are reviewed and discussed.


Virology ◽  
2010 ◽  
Vol 403 (2) ◽  
pp. 155-162 ◽  
Author(s):  
Edwin R. Manuel ◽  
Zhongde Wang ◽  
Zhongqi Li ◽  
Corinna La Rosa ◽  
Wendi Zhou ◽  
...  

2014 ◽  
Vol 25 (22) ◽  
pp. 3699-3708 ◽  
Author(s):  
Anyimilehidi Mazo-Vargas ◽  
Heungwon Park ◽  
Mert Aydin ◽  
Nicolas E. Buchler

Time-lapse fluorescence microscopy is an important tool for measuring in vivo gene dynamics in single cells. However, fluorescent proteins are limited by slow chromophore maturation times and the cellular autofluorescence or phototoxicity that arises from light excitation. An alternative is luciferase, an enzyme that emits photons and is active upon folding. The photon flux per luciferase is significantly lower than that for fluorescent proteins. Thus time-lapse luminescence microscopy has been successfully used to track gene dynamics only in larger organisms and for slower processes, for which more total photons can be collected in one exposure. Here we tested green, yellow, and red beetle luciferases and optimized substrate conditions for in vivo luminescence. By combining time-lapse luminescence microscopy with a microfluidic device, we tracked the dynamics of cell cycle genes in single yeast with subminute exposure times over many generations. Our method was faster and in cells with much smaller volumes than previous work. Fluorescence of an optimized reporter (Venus) lagged luminescence by 15–20 min, which is consistent with its known rate of chromophore maturation in yeast. Our work demonstrates that luciferases are better than fluorescent proteins at faithfully tracking the underlying gene expression.


2000 ◽  
Vol 41 (3) ◽  
pp. 259-277 ◽  
Author(s):  
C. M. CHANG ◽  
T. B. ELLIOTT ◽  
M. E. DOBSON ◽  
W. E. JACKSON ◽  
G. D. LEDNEY

2004 ◽  
Vol 24 (19) ◽  
pp. 8418-8427 ◽  
Author(s):  
Mikihiko Naito ◽  
Ryohei Katayama ◽  
Toshiyasu Ishioka ◽  
Akiko Suga ◽  
Kohei Takubo ◽  
...  

ABSTRACT Cellular FLIP (cFLIP) is a close homologue of caspase 8 without caspase activity that inhibits Fas signaling. The cFLIP protein is often expressed in human tumors and is believed to suppress antitumor immune responses involving the Fas system. Here, we report that a long form of cFLIP (cFLIP-L) inhibits β-catenin ubiquitylation and increases endogenous cytosolic β-catenin, which results in translocation of β-catenin into nuclei and induction of β-catenin-dependent gene expression in cFLIP-L-expressing cells. When cells stably expressing cFLIP-L were stimulated with Wnt3a, enhanced Wnt signaling was observed compared with the control cells. Conversely, depletion of endogenous cFLIP results in reduced Wnt signaling. Furthermore, cFLIP-L increases secondary-body axis formation when coinjected with suboptimal doses of β-catenin into early Xenopus embryos. Down-regulation of FADD by RNA-mediated interference abolishes the β-catenin-dependent gene expression induced by cFLIP-L. These results indicate that cFLIP-L, in cooperation with FADD, enhances canonical Wnt signaling by inhibiting proteasomal degradation of β-catenin, thus suggesting an additional mechanism involved with tumorgenesis, in addition to inhibiting Fas signaling.


2018 ◽  
Vol 285 (1870) ◽  
pp. 20172265 ◽  
Author(s):  
Jamie M. Caldwell ◽  
Megan J. Donahue ◽  
C. Drew Harvell

Understanding how disease risk varies over time and across heterogeneous populations is critical for managing disease outbreaks, but this information is rarely known for wildlife diseases. Here, we demonstrate that variation in host and pathogen factors drive the direction, duration and intensity of a coral disease outbreak. We collected longitudinal health data for 200 coral colonies, and found that disease risk increased with host size and severity of diseased neighbours, and disease spread was highest among individuals between 5 and 20 m apart. Disease risk increased by 2% with every 10 cm increase in host size. Healthy colonies with severely diseased neighbours (greater than 75% affected tissue) were 1.6 times more likely to develop disease signs compared with colonies with moderately diseased neighbours (25–75% affected tissue). Force of infection ranged from 7 to 20 disease cases per 1000 colonies (mean = 15 cases per 1000 colonies). The effective reproductive ratio, or average number of secondary infections per infectious individual, ranged from 0.16 to 1.22. Probability of transmission depended strongly on proximity to diseased neighbours, which demonstrates that marine disease spread can be highly constrained within patch reefs.


2021 ◽  
Vol 12 ◽  
Author(s):  
Piia Karisola ◽  
Kati Palosuo ◽  
Victoria Hinkkanen ◽  
Lukas Wisgrill ◽  
Terhi Savinko ◽  
...  

We previously reported the results of a randomized, open-label trial of egg oral immunotherapy (OIT) in 50 children where 44% were desensitized and 46% were partially desensitized after 8 months of treatment. Here we focus on cell-mediated molecular mechanisms driving desensitization during egg OIT. We sought to determine whether changes in genome-wide gene expression in blood cells during egg OIT correlate with humoral responses and the clinical outcome. The blood cell transcriptome of 50 children receiving egg OIT was profiled using peripheral blood mononuclear cell (PBMC) samples obtained at baseline and after 3 and 8 months of OIT. We identified 467 differentially expressed genes (DEGs) after 3 or 8 months of egg OIT. At 8 months, 86% of the DEGs were downregulated and played a role in the signaling of TREM1, IL-6, and IL-17. In correlation analyses, Gal d 1–4-specific IgG4 antibodies associated positively with DEGs playing a role in pathogen recognition and antigen presentation and negatively with DEGs playing a role in the signaling of IL-10, IL-6, and IL-17. Desensitized and partially desensitized patients had differences in their antibody responses, and although most of the transcriptomic changes were shared, both groups had also specific patterns, which suggest slower changes in partially desensitized and activation of NK cells in the desensitized group. OIT for egg allergy in children inhibits inflammation and activates innate immune responses regardless of the clinical outcome at 8 months. Changes in gene expression patterns first appear as posttranslational protein modifications, followed by more sustained epigenetic gene regulatory functions related to successful desensitization.


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