scholarly journals An impressive capacity for cold tolerance plasticity protects against ionoregulatory collapse in the disease vector, Aedes aegypti

2019 ◽  
Author(s):  
Amanda Jass ◽  
Gil Y. Yerushalmi ◽  
Hannah E. Davis ◽  
Andrew Donini ◽  
Heath A. MacMillan
Keyword(s):  
Aedes Aegypti ◽  
Cold Acclimation ◽  
Recovery Time ◽  
List Type ◽  
Cold Temperatures ◽  
Beneficial Effects ◽  
Disease Vector ◽  
Chill Coma ◽  
Insect Biogeography ◽  
Do So

AbstractThe mosquito Aedes aegypti is largely confined to tropical and subtropical regions but its range has recently been spreading to colder climates. As insect biogeography is closely tied to environmental temperature, understanding the limits of Ae. aegypti thermal tolerance and their capacity for phenotypic plasticity is important in predicting the spread of this species.In this study we report on the chill coma onset and recovery, as well as low temperature survival phenotypes of larvae and adults of Aedes aegypti that developed or were acclimated to 15°C (cold) or 25°C (warm).Developmental cold acclimation did not affect chill coma onset of larvae but substantially reduced chill coma onset temperatures in adults. Chill coma recovery time was affected by both temperature and the duration of exposure, and developmental and adult acclimation both strongly mitigated these effects and increased rates of survival following prolonged chilling.Female adults were far less likely to take a blood meal when cold acclimated and simply exposing females to blood (without feeding) attenuated some of the beneficial effects of cold acclimation on chill coma recovery time.Lastly, larvae suffered from hemolymph hyperkalemia when chilled, but development in the cold attenuated the imbalance, which suggests that acclimation can prevent cold-induced ionoregulatory collapse in this species.Our results demonstrate that Aedes aegypti larvae and adults have the capacity to acclimate to cold temperatures and do so at least in part by better maintaining ion balance in the cold. This ability for cold acclimation may facilitate the spread of this species to higher latitudes, particularly in an era of climate change.

scholarly journals Multiple paths to cold tolerance: the role of environmental cues, morphological traits and the circadian clock gene vrille

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Noora Poikela ◽  
Venera Tyukmaeva ◽  
Anneli Hoikkala ◽  
Maaria Kankare
Keyword(s):  
Circadian Clock ◽  
Cold Acclimation ◽  
Cold Tolerance ◽  
Recovery Time ◽  
Morphological Traits ◽  
Clock Gene ◽  
Circadian Clock Gene ◽  
Chill Coma ◽  
The Impact ◽  
Insect Cold Tolerance

Abstract Background Tracing the association between insect cold tolerance and latitudinally and locally varying environmental conditions, as well as key morphological traits and molecular mechanisms, is essential for understanding the processes involved in adaptation. We explored these issues in two closely-related species, Drosophila montana and Drosophila flavomontana, originating from diverse climatic locations across several latitudes on the coastal and mountainous regions of North America. We also investigated the association between sequence variation in one of the key circadian clock genes, vrille, and cold tolerance in both species. Finally, we studied the impact of vrille on fly cold tolerance and cold acclimation ability by silencing it with RNA interference in D. montana. Results We performed a principal component analysis (PCA) on variables representing bioclimatic conditions on the study sites and used latitude as a proxy of photoperiod. PC1 separated the mountainous continental sites from the coastal ones based on temperature variability and precipitation, while PC2 arranged the sites based on summer and annual mean temperatures. Cold tolerance tests showed D. montana to be more cold-tolerant than D. flavomontana and chill coma resistance (CTmin) of this species showed an association with PC2. Chill coma recovery time (CCRT) of both species improved towards northern latitudes, and in D. flavomontana this trait was also associated with PC1. D. flavomontana flies were darkest in the coast and in the northern mountainous populations, but coloration showed no linkage with cold tolerance. Body size decreased towards cold environments in both species, but only within D. montana populations largest flies showed fastest recovery from cold. Finally, both the sequence analysis and RNAi study on vrille suggested this gene to play an essential role in D. montana cold resistance and acclimation, but not in recovery time. Conclusions Our study demonstrates the complexity of insect cold tolerance and emphasizes the need to trace its association with multiple environmental variables and morphological traits to identify potential agents of natural selection. It also shows that a circadian clock gene vrille is essential both for short- and long-term cold acclimation, potentially elucidating the connection between circadian clock system and cold tolerance.

scholarly journals Chill coma onset and recovery fail to reveal true variation in thermal performance among populations of Drosophila melanogaster

2020 ◽  
Author(s):  
Hannah E. Davis ◽  
Alexandra Cheslock ◽  
Heath A. MacMillan
Keyword(s):  
Drosophila Melanogaster ◽  
Cold Exposure ◽  
Thermal Tolerance ◽  
Recovery Time ◽  
Population Level ◽  
Onset Temperature ◽  
List Type ◽  
Chill Coma ◽  
Geographic Origins ◽  
Insect Populations

AbstractSpecies from colder climates tend to be more chill tolerant regardless of the chill tolerance trait measured, but for Drosophila melanogaster, population-level differences in chill tolerance among populations are not always found when a single trait is measured in the laboratory.We measured chill coma onset temperature, chill coma recovery time, and survival after chronic cold exposure in replicate lines derived from multiple paired African and European D. melanogaster populations. The populations in our study were previously found to differ in chronic cold survival ability, which is believed to have evolved independently in each population pair.To our surprise, the populations did not differ in chill coma onset temperature and chill coma recovery time in a manner that reflected their geographic origins, even though these traits are known to vary with origin latitude among Drosophila species and among the most common metrics of thermal tolerance in insects. The populations did, however, still differ in their ability to survive chronic cold exposure.While it is common practice to measure only one chill tolerance trait when comparing chill tolerance among insect populations, our results emphasise the importance of measuring more than one thermal tolerance trait to minimize the risk of missing real adaptive variation in insect thermal tolerance.

scholarly journals Larval Diet Abundance Influences Size and Composition of the Midgut Microbiota of Aedes aegypti Mosquitoes

2021 ◽  
Vol 12 ◽  
Author(s):  
Hannah J. MacLeod ◽  
George Dimopoulos ◽  
Sarah M. Short
Keyword(s):  
Aedes Aegypti ◽  
Bacterial Load ◽  
Amplicon Sequencing ◽  
Larval Diet ◽  
Microbiota Composition ◽  
Vector Species ◽  
Larval Food ◽  
Disease Vector ◽  
16S Amplicon Sequencing ◽  
The Impact

The midgut microbiota of the yellow fever mosquito Aedes aegypti impacts pathogen susceptibility and transmission by this important vector species. However, factors influencing the composition and size of the microbiome in mosquitoes are poorly understood. We investigated the impact of larval diet abundance during development on the composition and size of the larval and adult microbiota by rearing Aedes aegypti under four larval food regimens, ranging from nutrient deprivation to nutrient excess. We assessed the persistent impacts of larval diet availability on the microbiota of the larval breeding water, larval mosquitoes, and adult mosquitoes under sugar and blood fed conditions using qPCR and high-throughput 16S amplicon sequencing to determine bacterial load and microbiota composition. Bacterial loads in breeding water increased with increasing larval diet. Larvae reared with the lowest diet abundance had significantly fewer bacteria than larvae from two higher diet treatments, but not from the highest diet abundance. Adults from the lowest diet abundance treatment had significantly fewer bacteria in their midguts compared to all higher diet abundance treatments. Larval diet amount also had a significant impact on microbiota composition, primarily within larval breeding water and larvae. Increasing diet correlated with increased relative levels of Enterobacteriaceae and Flavobacteriaceae and decreased relative levels of Sphingomonadaceae. Multiple individual OTUs were significantly impacted by diet including one mapping to the genus Cedecea, which increased with higher diet amounts. This was consistent across all sample types, including sugar fed and blood fed adults. Taken together, these data suggest that availability of diet during development can cause lasting shifts in the size and composition of the microbiota in the disease vector Aedes aegypti.

scholarly journals Pituitary injury and persistent hypofunction resulting from a peripartum non-hemorrhagic, vaso-occlusive event

2015 ◽  
Vol 2015 ◽  
Author(s):  
Anita Kuriya ◽  
David V Morris ◽  
Michael H Dahan
Keyword(s):  
Literature Review ◽  
Pituitary Gland ◽  
Dopamine Agonists ◽  
List Type ◽  
Fetal Demise ◽  
Common Cause ◽  
The Past ◽  
Vascular Accidents ◽  
Learning Points ◽  
Do So

Summary Cerebral vascular accidents are caused by vasospasm when induced by preeclampsia or by dopamine agonists. However, six arteries nourish the pituitary and prevent against vasospasm-induced damage, which up until now has not been thought to occur. Bromocriptine was used to arrest lactation in a 31-year-old with secondary amenorrhea following preeclampsia and fetal demise at 28 weeks gestation. Tests and history revealed panhypopituitarism not associated with hemorrhage or mass infarction but instead caused by vasospasm. The present study is the first report of pituitary damage from a non-hemorrhagic, vaso-occlusive event in the literature. In keeping with Sheehan's and Simon's syndromes, we have named pituitary damage resulting from vaso-occlusion as Dahan's syndrome, and a literature review suggests that it may be a common and previously overlooked disorder. Learning points Vasospasm can cause damage to the pituitary gland, although it was not previously believed to do so. Preeclampsia and the use of a dopamine agonist, particularly in the peripartum state, may trigger vasospasm. Vasospasm resulting from dopamine agonists may be a common cause of injury to the pituitary gland, and it may have been overlooked in the past.

scholarly journals Cold Acclimation of the Thermoacidophilic Red Alga Galdieria sulphuraria: Changes in Gene Expression and Involvement of Horizontally Acquired Genes

2018 ◽  
Vol 60 (3) ◽  
pp. 702-712 ◽  
Author(s):  
Alessandro W Rossoni ◽  
Gerald Sch�nknecht ◽  
Hyun Jeong Lee ◽  
Ryan L Rupp ◽  
Samantha Flachbart ◽  
...  
Keyword(s):  
Gene Expression ◽  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Cold Acclimation ◽  
Growth Temperature ◽  
Toxic Metal ◽  
Optimal Growth ◽  
Red Alga ◽  
Galdieria Sulphuraria ◽  
Cold Temperatures

Abstract Galdieria sulphuraria is a unicellular red alga that lives in hot, acidic, toxic metal-rich, volcanic environments, where few other organisms survive. Its genome harbors up to 5% of genes that were most likely acquired through horizontal gene transfer. These genes probably contributed to G.sulphuraria’s adaptation to its extreme habitats, resulting in today’s polyextremophilic traits. Here, we applied RNA-sequencing to obtain insights into the acclimation of a thermophilic organism towards temperatures below its growth optimum and to study how horizontally acquired genes contribute to cold acclimation. A decrease in growth temperature from 42�C/46�C to 28�C resulted in an upregulation of ribosome biosynthesis, while excreted proteins, probably components of the cell wall, were downregulated. Photosynthesis was suppressed at cold temperatures, and transcript abundances indicated that C-metabolism switched from gluconeogenesis to glycogen degradation. Folate cycle and S-adenosylmethionine cycle (one-carbon metabolism) were transcriptionally upregulated, probably to drive the biosynthesis of betaine. All these cold-induced changes in gene expression were reversible upon return to optimal growth temperature. Numerous genes acquired by horizontal gene transfer displayed temperature-dependent expression changes, indicating that these genes contributed to adaptive evolution in G.sulphuraria.

The Global Expansion of Dengue: How Aedes aegypti Mosquitoes Enabled the First Pandemic Arbovirus

2020 ◽  
Vol 65 (1) ◽  
pp. 191-208 ◽  
Author(s):  
Oliver J. Brady ◽  
Simon I. Hay
Keyword(s):  
Invasive Species ◽  
Aedes Aegypti ◽  
Infectious Diseases ◽  
Control Strategies ◽  
Viral Disease ◽  
Rapid Rise ◽  
Disease Vector ◽  
Research Priority ◽  
Global Spread ◽  
Human Habitation

Dengue is an emerging viral disease principally transmitted by the Aedes ( Stegomyia) aegypti mosquito. It is one of the fastest-growing global infectious diseases, with 100–400 million new infections a year, and is now entrenched in a growing number of tropical megacities. Behind this rapid rise is the simple adaptation of Ae. aegypti to a new entomological niche carved out by human habitation. This review describes the expansion of dengue and explores how key changes in the ecology of Ae. aegypti allowed it to become a successful invasive species and highly efficient disease vector. We argue that characterizing geographic heterogeneity in mosquito bionomics will be a key research priority that will enable us to better understand future dengue risk and design control strategies to reverse its global spread.

scholarly journals CAPA neuropeptides and their receptor form an anti-diuretic hormone signaling system in the human disease vector, Aedes aegypti

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Farwa Sajadi ◽  
Ali Uyuklu ◽  
Christine Paputsis ◽  
Aryan Lajevardi ◽  
Azizia Wahedi ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Human Disease ◽  
Hormone Signaling ◽  
Signaling System ◽  
Diuretic Hormone ◽  
Disease Vector

Is Reputation Good or Bad? An Experiment

2010 ◽  
Vol 100 (5) ◽  
pp. 2187-2204 ◽  
Author(s):  
Brit Grosskopf ◽  
Rajiv Sarin
Keyword(s):  
Laboratory Experiment ◽  
Harmful Effect ◽  
Beneficial Effects ◽  
The Past ◽  
Long Run ◽  
Short Run ◽  
Other Regarding ◽  
The Impact ◽  
Other Regarding Preferences ◽  
Do So

We investigate the impact of reputation in a laboratory experiment. We do so by varying whether the past choices of a long-run player are observable by the short-run players. Our framework allows for reputation to have either a beneficial or a harmful effect on the long-run player. We find that reputation is seldom harmful and its beneficial effects are not as strong as theory suggests. When reputational concerns are at odds with other-regarding preferences, we find the latter overwhelm the former. (JEL C91, D12, D82, D83, Z13)

scholarly journals The Developmental Transcriptome of Ae. albopictus, a Major Worldwide Human Disease Vector

2019 ◽  
Author(s):  
Stephanie Gamez ◽  
Igor Antoshechkin ◽  
Stelia C. Mendez-Sanchez ◽  
Omar S. Akbari
Keyword(s):  
Aedes Aegypti ◽  
Aedes Albopictus ◽  
Human Disease ◽  
Control Strategies ◽  
Expression Profiles ◽  
Expression Patterns ◽  
Significant Differential Expression ◽  
Disease Vector ◽  
Biological Studies ◽  
Similarities And Differences

AbstractAedes albopictus mosquitoes are important vectors for a number of human pathogens including the Zika, dengue, and chikungunya viruses. Capable of displacing Aedes aegypti populations, it adapts to cooler environments which increases its geographical range and transmission potential. There are limited control strategies for Aedes albopictus mosquitoes which is likely attributed to the lack of comprehensive biological studies on this emerging vector. To fill this void, here using RNAseq we characterized Aedes albopictus mRNA expression profiles at 47 distinct time points throughout development providing the first high-resolution comprehensive view of the developmental transcriptome of this worldwide human disease vector. This enabled us to identify several patterns of shared gene expression among tissues as well as sex-specific expression patterns. Moreover, to illuminate the similarities and differences between Aedes aegypti, a related human disease vector, we performed a comparative analysis using the two developmental transcriptomes. We identify life stages were the two species exhibited significant differential expression among orthologs. These findings provide insights into the similarities and differences between Aedes albopictus and Aedes aegypti mosquito biology. In summary, the results generated from this study should form the basis for future investigations on the biology of Aedes albopictus mosquitoes and provide a goldmine resource for the development of transgene-based vector control strategies.

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