Selection-driven adaptation to the extreme Antarctic environment in the Emperor penguin

The eco-evolutionary history of penguins is profoundly influenced by their shift from temperate to cold environments. Breeding only in Antarctica during the winter, the Emperor penguin appears as an extreme outcome of this process, with unique features related to insulation, heat production and energy management. However, whether this species actually diverged from a less cold-adapted ancestor, thus more similar in ecology to its sister species, the King penguin, is still an open question. As the Antarctic niche shift likely resulted in vast changes in selective pressure experienced by the Emperor penguin, the identification and relative quantification of the genomic signatures of selection, unique to each of these sister species, could answer this question. Applying a suite of phylogeny-based methods on 7,651 orthologous gene alignments of seven penguins and 13 other birds, we identified a set of candidate genes showing significantly different selection regimes either in the Emperor or in the King penguin lineage. Our comparative approach unveils a more pervasive selection shift in the Emperor penguin, supporting the hypothesis that its extreme cold adaptation is a derived state from a more King penguin-like ecology. Among the candidate genes under selection in the Emperor penguin, four genes (TRPM8, LEPR, CRB1, and SFI1) were identified before in other cold adapted vertebrates, while, on the other hand, 161 genes can be assigned to functional pathways relevant to cold adaptation (e.g., cardiovascular system, lipid, fatty acid and glucose metabolism, insulation, etc.). Our results show that extreme cold adaptation in the Emperor penguin largely involved unique genetic options which, however, affect metabolic and physiological traits common to other cold-adapted homeotherms.

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Increased ACTH response to corticotropin-releasing factor in cold-adapted rats in vivo

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.1989.257.3.e336 ◽

1989 ◽

Vol 257 (3) ◽

pp. E336-E339 ◽

Cited By ~ 1

Author(s):

A. Uehara ◽

Y. Habara ◽

A. Kuroshima ◽

C. Sekiya ◽

Y. Takasugi ◽

...

Keyword(s):

Stress Responses ◽

Cold Adaptation ◽

Corticotropin Releasing Factor ◽

Plasma Acth ◽

Cold Adapted ◽

Repeated Restraint Stress ◽

Cross Adaptation ◽

Freely Moving ◽

Increased Activity

We have recently reported that chronically repeated restraint stress results in improved cold tolerance in rats via an increased activity of nonshivering thermogenesis, a characteristic metabolic change observed during cold adaptation, suggesting the presence of cross-adaptation between cold and stress. It is well established that the hypothalamic-pituitary-adrenal (HPA) axis is activated in various stress responses. In the present study, therefore, we examined whether cold adaptation would alter the adrenocorticotropic hormone (ACTH)-releasing state in vivo using freely moving, conscious rats chronically implanted with intra-atrial cannulas. There was no difference in the basal levels of plasma ACTH between warm control and cold-adapted rats. On the other hand, the ACTH response to the intravenous administration of corticotropin-releasing factor (CRF; 2 micrograms/animal) was significantly elevated in cold-adapted rats. However, the injection of 10 micrograms of CRF, which was considered as a dose to elicit the maximal ACTH response, resulted in similar ACTH release patterns between the two groups. These changes in the responsiveness of ACTH secretion have been observed in rats chronically exposed to stressful conditions. The results demonstrated in the present study, therefore, provide further evidence for our hypothesis that there may exist cross-adaptation between cold and nonthermal stress.

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The Effects of Thyroxine and Isopropylnoradrenaline on Cytochrome Oxidase Activity in Brown Adipose Tissue

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y73-114 ◽

1973 ◽

Vol 51 (10) ◽

pp. 751-758 ◽

Cited By ~ 26

Author(s):

H. M. C. Heick ◽

C. Vachon ◽

Mary Ann Kallai ◽

Nicole Bégin-Heick ◽

J. LeBlanc

Keyword(s):

Adipose Tissue ◽

Brown Adipose Tissue ◽

Protein Content ◽

Cytochrome Oxidase ◽

Cold Adaptation ◽

Metabolic Response ◽

Mitochondrial Enzymes ◽

Cold Adapted ◽

Brown Adipose ◽

Hormonal Treatments

Groups of animals were treated with injections of isopropylnoradrenaline, thyroxine, or both hormones together. The effects of these hormonal treatments on the size, protein content, and level of some mitochondrial enzymes, in particular the cytochrome oxidase, were determined and compared to the effect on these parameters produced by cold adaptation. The changes observed were correlated with the resistance of the animals to cold stress and with their metabolic response to injections of isopropylnoradrenaline. All treatments increased the size of the brown adipose tissue. Whereas thyroxine had little effect on the protein content and cytochrome oxidase, both isopropylnoradrenaline and cold adaptation produced increases in these parameters. It appears that the isopropylnoradrenaline-treated animals mimic more closely the cold-adapted animals than do those with thyroxine treatment. However, the isopropylnoradrenaline-treated animals are not as resistant to cold as the cold-adapted animals.

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Tissue-specific cis-regulatory divergence implicates a fatty acid elongase necessary for inhibiting interspecies mating in Drosophila

10.1101/344754 ◽

2018 ◽

Author(s):

Peter A. Combs ◽

Joshua J. Krupp ◽

Neil M. Khosla ◽

Dennis Bua ◽

Dmitri A. Petrov ◽

...

Keyword(s):

Fatty Acid ◽

Candidate Genes ◽

Molecular Mechanisms ◽

Sister Species ◽

F1 Hybrids ◽

Rna Seq ◽

Fatty Acid Elongase ◽

Tissue Specific ◽

Regulatory Changes ◽

Wide Range

AbstractPheromones known as cuticular hydrocarbons are a major component of reproductive isolation in Drosophila. Individuals from morphologically similar sister species produce different sets of hydrocarbons that allow potential mates to identify them as a suitable partner. In order to explore the molecular mechanisms underlying speciation, we performed RNA-seq in F1 hybrids to measure tissue-specific cis-regulatory divergence between the sister species D. simulans and D. sechellia. By focusing on cis-regulatory changes specific to female oenocytes, we rapidly identified a small number of candidate genes. We found that one of these, the fatty acid elongase eloF, broadly affects both the complement of hydrocarbons present on D. sechellia females and the propensity of D. simulans males to mate with those females. In addition, knockdown of eloF in the more distantly related D. melanogaster led to a similar shift in hydrocarbons as well as lower interspecific mate discrimination by D. simulans males. Thus, cis-regulatory changes in eloF appear to be a major driver in the sexual isolation of D. simulans from multiple other species. More generally, our RNA-seq approach proved to be far more efficient than QTL mapping in identifying candidate genes; the same framework can be used to pinpoint cis-regulatory drivers of divergence in a wide range of traits differing between any interfertile species.

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The effect of cold adaptation on kinetics of insulin and growth hormone in heifers

Canadian Journal of Animal Science ◽

10.4141/cjas93-003 ◽

1993 ◽

Vol 73 (1) ◽

pp. 33-47 ◽

Cited By ~ 4

Author(s):

S. L. Scott ◽

R. J. Christopherson

Keyword(s):

Growth Hormone ◽

Cold Adaptation ◽

Slow Component ◽

Plasma Concentrations ◽

Endocrine System ◽

Insulin Injection ◽

Metabolic Clearance ◽

Cold Environment ◽

Cold Adapted ◽

Total Turnover

Ten Holstein heifers 1 yr of age were housed in groups of five in temperature-controlled environmental chambers maintained at either 20 °C (warm environment) or − 17 °C (cold environment). Each heifer received an injection of insulin or growth hormone followed by frequent blood sampling. Plasma samples were analyzed for insulin, insulin-like growth factor I (IGF-1), growth hormone, glucagon, triiodothyronine, thyroxine and glucose. Basal plasma concentrations of all hormones except growth hormone and IGF-1 were elevated (P < 0.05) in the cold environment. Kinetic parameters for growth hormone and insulin were calculated using a two-pool model. Both the zero-time intercept and the rate constant for the slow component of growth hormone were lower (P < 0.05) in cold-adapted animals. The total turnover rate of growth hormone in both pools also tended to be reduced by cold adaptation (P < 0.07). The reduction in growth-hormone turnover may be related to the reduced average daily gains that were observed in the cold (P < 0.05). Plasma glucose concentration following both the insulin and growth-hormone injections was higher in the cold-adapted heifers (P < 0.001 and P < 0.05, respectively). The response of glucagon to insulin injection was greater in the cold (P < 0.05), as was the response of IGF-I to growth-hormone injection (P < 0.10). These cold-induced alterations in the endocrine system appear to be directed toward providing substrates, including glucose, for use in thermogenesis rather than growth. Key words: Cold adaptation, growth hormone, insulin, metabolic clearance rate, hormone kinetics, cattle

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Survival of halophilic Archaea in Earth's cold stratosphere

International Journal of Astrobiology ◽

10.1017/s1473550416000410 ◽

2016 ◽

Vol 16 (4) ◽

pp. 321-327 ◽

Cited By ~ 11

Author(s):

P. DasSarma ◽

V.J. Laye ◽

J. Harvey ◽

C. Reid ◽

J. Shultz ◽

...

Keyword(s):

Low Temperatures ◽

Cold Adaptation ◽

Halophilic Archaea ◽

Cold Temperature ◽

Freezing And Thawing ◽

Cold Adapted ◽

Liquid Cultures ◽

Genome Wide ◽

Temperature Exposure ◽

Genetic Responses

AbstractHalophilic Archaea are known to tolerate multiple extreme conditions on Earth and have been proposed as models for astrobiology. In order to assess the importance of cold-adaptation of these microorganisms in surviving stratospheric conditions, we launched live, liquid cultures of two species, the mesophilic model Halobacterium sp. NRC-1 and the cold-adapted Antarctic isolate Halorubrum lacusprofundi ATCC 49239, on helium balloons. After return to Earth, the cold-adapted species showed nearly complete survival while the mesophilic species exhibited slightly reduced viability. Parallel studies found that the cold-adapted species was also better able to survive freezing and thawing in the laboratory. Genome-wide transcriptomic analysis was used to compare the two haloarchaea at optimum growth temperatures versus low temperatures supporting growth. The cold-adapted species displayed perturbation of a majority of genes upon cold temperature exposure, divided evenly between up-regulated and down-regulated genes, while the mesophile exhibited perturbation of only a fifth of its genes, with nearly two-thirds being down-regulated. These results underscore the importance of genetic responses of H. lacusprofundi to cold temperature for enhanced survival in the stratosphere.

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Abstract 8: Reprogramming of Adult Mammalian Cardiomyocytes Towards Proliferation and Regeneration Through Comparative Analyses of Epicardial and Myocardial Cells

Circulation Research ◽

10.1161/res.117.suppl_1.8 ◽

2015 ◽

Vol 117 (suppl_1) ◽

Author(s):

Guo Huang ◽

Justin Judd ◽

Jonathan Lovas

Keyword(s):

Cell Cycle ◽

Candidate Genes ◽

Heart Development ◽

Comparative Approach ◽

Myocardial Cells ◽

Cardiomyocyte Proliferation ◽

Developmental Gene ◽

Cardiac Muscle Cells ◽

Comparative Analyses ◽

Epicardial Cells

Heart development and regeneration require an elegant balance of cell proliferation and differentiation. In both adult zebrafish and neonatal mouse cardiac regeneration, new cardiomyocytes are shown to originate from pre-existing cardiomyocytes through de-differentiation of mature cells to the immature progenitor cell state, with developmental gene program reactivation and cell cycle reentry. Interestingly, after adult mammalian cardiac injury, both cardiac muscle cells and the epicardial cells that envelope the heart reinitiate developmental gene programs. However, adult epicardial cells are able to proliferate following injury but adult cardiomyocytes are not capable. We investigated the genetic circuitry of mouse epicardial cells and myocardial cells in different developmental stages and in response to injury. Such comparative analyses revealed a group of ~50 candidate genes that may be responsible for the permanent cell cycle arrest of cardiomyocytes. We generated adenoviruses that express these candidate genes individually, and demonstrated that the mixed viral pool possessed a robust activity to promote proliferation of adult mouse cardiomyocytes. Our comparative approach and functional screens may lead to identification of the dormant genetic circuitry in adult mammalian heart that can be reactivated to drive robust cardiomyocyte proliferation and regeneration.

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Pathobiological and Genomic Characterization of a Cold-Adapted Infectious Bronchitis Virus (BP-caKII)

Viruses ◽

10.3390/v10110652 ◽

2018 ◽

Vol 10 (11) ◽

pp. 652

Author(s):

Seung-Min Hong ◽

Se-Hee An ◽

Chung-Young Lee ◽

Chang-Seon Song ◽

Kang-Seuk Choi ◽

...

Keyword(s):

Infectious Bronchitis Virus ◽

Cold Adaptation ◽

Reproductive Tract ◽

Genomic Sequence ◽

Live Attenuated Vaccine ◽

Genetic Changes ◽

Cold Adapted ◽

Infectious Bronchitis ◽

Field Virus ◽

Specific Pathogen

We established a cold-adapted infectious bronchitis virus (BP-caKII) by passaging a field virus through specific pathogen-free embryonated eggs 20 times at 32 °C. We characterized its growth kinetics and pathogenicity in embryonated eggs, and its tropism and persistence in different tissues from chickens; then, we evaluated pathogenicity by using a new premature reproductive tract pathogenicity model. Furthermore, we determined the complete genomic sequence of BP-caKII to understand the genetic changes related to cold adaptation. According to our results, BP-caKII clustered with the KII genotype viruses K2 and KM91, and showed less pathogenicity than K2, a live attenuated vaccine strain. BP-caKII showed delayed viremia, resulting in its delayed dissemination to the kidneys and cecal tonsils compared to K2 and KM91, the latter of which is a pathogenic field strain. A comparative genomics study revealed similar nucleotide sequences between BP-caKII, K2 and KM91 but clearly showed different mutations among them. BP-caKII shared several mutations with K2 (nsp13, 14, 15 and 16) following embryo adaptation but acquired multiple additional mutations in nonstructural proteins (nsp3, 4 and 12), spike proteins and nucleocapsid proteins following cold adaptation. Thus, the establishment of BP-caKII and the identified mutations in this study may provide insight into the genetic background of embryo and cold adaptations, and the attenuation of coronaviruses.

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