Stress tolerance in a polyextremophile: the southernmost insect

2015 ◽  
Vol 93 (9) ◽  
pp. 679-686 ◽  
Author(s):  
R.E. Lee ◽  
D.L. Denlinger
Keyword(s):  
Biotic Interactions ◽  
Cross Tolerance ◽  
Atp Production ◽  
Genome Wide ◽  
Rapid Cold Hardening ◽  
Belgica Antarctica ◽  
Genes Encoding ◽  
Shock Proteins ◽  
The Antarctic ◽  
Autophagy Inhibition

Since biotic interactions within the simple terrestrial communities on the Antarctic Peninsula are limited compared with tropical and temperate regions, survival is largely dictated by the numerous abiotic challenges. Our research focuses on adaptations to environmental stresses experienced by the Antarctic midge (Belgica antarctica Jacobs, 1900), the southernmost free-living insect. Midge larvae can survive freezing and anoxia year-round. Not only can frozen larvae undergo rapid cold-hardening (RCH) at temperatures as low as –12 °C, but RCH develops more rapidly in frozen compared with supercooled larvae. Whether larvae overwinter in a frozen state or cryoprotectively dehydrated may depend on hydration levels within their hibernacula. Larvae constitutively up-regulate genes encoding heat shock proteins, as well as the antioxidant enzymes superoxide dismutase and catalase. Larvae accumulate osmoprotectants in response to freezing, desiccation, and exposure to seawater; exposure to one of these osmotic stressors confers cross-tolerance to the others. Molecular responses to dehydration stress include extensive genome-wide changes that include differential expression of aquaporins among tissues, upregulation of pathways associated with autophagy, inhibition of apoptosis, and downregulation of metabolism and ATP production.

scholarly journals Environmental factors influencing fine-scale distribution of Antarctica’s only endemic insect

Oecologia ◽  
2020 ◽  
Vol 194 (4) ◽  
pp. 529-539
Author(s):  
Leslie J. Potts ◽  
J. D. Gantz ◽  
Yuta Kawarasaki ◽  
Benjamin N. Philip ◽  
David J. Gonthier ◽  
...  
Keyword(s):  
Antarctic Peninsula ◽  
Spatial Scales ◽  
Abiotic Factors ◽  
Ecological Factors ◽  
Biotic Interactions ◽  
Species Distributions ◽  
Biotic Factors ◽  
Belgica Antarctica ◽  
Abiotic And Biotic Factors ◽  
The Antarctic

AbstractSpecies distributions are dependent on interactions with abiotic and biotic factors in the environment. Abiotic factors like temperature, moisture, and soil nutrients, along with biotic interactions within and between species, can all have strong influences on spatial distributions of plants and animals. Terrestrial Antarctic habitats are relatively simple and thus good systems to study ecological factors that drive species distributions and abundance. However, these environments are also sensitive to perturbation, and thus understanding the ecological drivers of species distribution is critical for predicting responses to environmental change. The Antarctic midge, Belgica antarctica, is the only endemic insect on the continent and has a patchy distribution along the Antarctic Peninsula. While its life history and physiology are well studied, factors that underlie variation in population density within its range are unknown. Previous work on Antarctic microfauna indicates that distribution over broad scales is primarily regulated by soil moisture, nitrogen content, and the presence of suitable plant life, but whether these patterns are true over smaller spatial scales has not been investigated. Here we sampled midges across five islands on the Antarctic Peninsula and tested a series of hypotheses to determine the relative influences of abiotic and biotic factors on midge abundance. While historical literature suggests that Antarctic organisms are limited by the abiotic environment, our best-supported hypothesis indicated that abundance is predicted by a combination of abiotic and biotic conditions. Our results are consistent with a growing body of literature that biotic interactions are more important in Antarctic ecosystems than historically appreciated.

Rapid cold-hardening in larvae of the Antarctic midge Belgica antarctica: cellular cold-sensing and a role for calcium

2008 ◽  
Vol 294 (6) ◽  
pp. R1938-R1946 ◽  
Author(s):  
Nicholas M. Teets ◽  
Michael A. Elnitsky ◽  
Joshua B. Benoit ◽  
Giancarlo Lopez-Martinez ◽  
David L. Denlinger ◽  
...  
Keyword(s):  
Cell Survival ◽  
Freezing Tolerance ◽  
Fat Body ◽  
Malpighian Tubules ◽  
Cold Hardening ◽  
Rapid Cold Hardening ◽  
Belgica Antarctica ◽  
The Antarctic ◽  
Cold Sensing

In many insects, the rapid cold-hardening (RCH) response significantly enhances cold tolerance in minutes to hours. Larvae of the Antarctic midge, Belgica antarctica, exhibit a novel form of RCH, by which they increase their freezing tolerance. In this study, we examined whether cold-sensing and RCH in B. antarctica occur in vitro and whether calcium is required to generate RCH. As demonstrated previously, 1 h at −5°C significantly increased organismal freezing tolerance at both −15°C and −20°C. Likewise, RCH enhanced cell survival of fat body, Malpighian tubules, and midgut tissue of larvae frozen at −20°C. Furthermore, isolated tissues retained the capacity for RCH in vitro, as demonstrated with both a dye exclusion assay and a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT)-based viability assay, thus indicating that cold-sensing and RCH in B. antarctica occur at the cellular level. Interestingly, there was no difference in survival between tissues that were supercooled at −5°C and those frozen at −5°C, suggesting that temperature mediates the RCH response independent of the freezing of body fluids. Finally, we demonstrated that calcium is required for RCH to occur. Removing calcium from the incubating solution slightly decreased cell survival after RCH treatments, while blocking calcium with the intracellular chelator BAPTA-AM significantly reduced survival in the RCH treatments. The calmodulin inhibitor N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide hydrochloride (W-7) also significantly reduced cell survival in the RCH treatments, thus supporting a role for calcium in RCH. This is the first report implicating calcium as an important second messenger in the RCH response.

Characterization of drought-induced rapid cold-hardening in the Antarctic midge, Belgica antarctica

Polar Biology ◽  
2019 ◽  
Vol 42 (6) ◽  
pp. 1147-1156 ◽  
Author(s):  
Yuta Kawarasaki ◽  
Nicholas M. Teets ◽  
Benjamin N. Philip ◽  
Leslie J. Potts ◽  
J. D. Gantz ◽  
...  
Keyword(s):  
Cold Hardening ◽  
Rapid Cold Hardening ◽  
Belgica Antarctica ◽  
The Antarctic

scholarly journals Brief exposure to a diverse range of environmental stress enhances stress tolerance in the polyextremophilic Antarctic midge, Belgica antarctica

2020 ◽  
Author(s):  
J. D. Gantz ◽  
B. N. Philip ◽  
N. M. Teets ◽  
Y. Kawarasaki ◽  
L. J. Potts ◽  
...  
Keyword(s):  
Environmental Stress ◽  
Stress Tolerance ◽  
Cold Tolerance ◽  
Abiotic Stresses ◽  
Environmental Cues ◽  
Ambient Conditions ◽  
Diverse Range ◽  
Rapid Cold Hardening ◽  
Belgica Antarctica ◽  
The Antarctic

AbstractInsects use rapid acclimation to enhance their tolerance of abiotic stresses within minutes to hours. These responses are critical adaptations for insects and other small ectotherms to tolerate drastic changes in temperature, hydration, or other factors that can fluctuate precipitously with ambient conditions or as a result of behavior. Rapid cold-hardening, where insects use brief exposure to modest chilling as a cue to enhance their cold tolerance, is the most thoroughly-studied of these responses and relatively little is known about rapid acclimation that is either triggered by or enhances tolerance of other abiotic stresses. Here, we used larvae of the Antarctic midge, Belgica antarctica, a polar extremophile that routinely experiences numerous stresses in nature, to investigate how 2 h exposure to modest environmental stresses affect stress tolerance in insects. Brief pretreatment by various stresses, including hyperosmotic challenge, hypoosmotic challenge, acidity, basicity, and UV irradiation enhanced stress tolerance in B. antarctica larvae relative to untreated controls. These results indicate that numerous environmental cues can trigger rapid acclimation in insects and that these responses can enhance tolerance of multiple stresses.

scholarly journals Genome-wide CRISPR/Cas9 screening identifies CARHSP1 responsible for radiation resistance in glioblastoma

2021 ◽  
Vol 12 (8) ◽  
Author(s):  
Guo-dong Zhu ◽  
Jing Yu ◽  
Zheng-yu Sun ◽  
Yan Chen ◽  
Hong-mei Zheng ◽  
...  
Keyword(s):  
Cold Shock ◽  
Mrna Level ◽  
Critical Role ◽  
Inflammatory Signaling ◽  
Heat Stable ◽  
Genome Wide ◽  
Attractive Therapeutic Target ◽  
Heat Stable Protein ◽  
Signaling Activation ◽  
Shock Proteins

AbstractGlioblastomas (GBM) is the most common primary malignant brain tumor, and radiotherapy plays a critical role in its therapeutic management. Unfortunately, the development of radioresistance is universal. Here, we identified calcium-regulated heat-stable protein 1 (CARHSP1) as a critical driver for radioresistance utilizing genome-wide CRISPR activation screening. This is a protein with a cold-shock domain (CSD)-containing that is highly similar to cold-shock proteins. CARHSP1 mRNA level was upregulated in irradiation-resistant GBM cells and knockdown of CARHSP1 sensitized GBM cells to radiotherapy. The high expression of CARHSP1 upon radiation might mediate radioresistance by activating the inflammatory signaling pathway. More importantly, patients with high levels of CARHSP1 had poorer survival when treated with radiotherapy. Collectively, our findings suggested that targeting the CARHSP1/TNF-α inflammatory signaling activation induced by radiotherapy might directly affect radioresistance and present an attractive therapeutic target for GBM, particularly for patients with high levels of CARHSP1.

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