8. The Migratory Cycle of Atonement

2019 ◽  
pp. 216-232
Keyword(s):  
2018 ◽  
Vol 19 (10) ◽  
pp. 2970 ◽  
Author(s):  
Luigi Catacuzzeno ◽  
Fabio Franciolini

Cell migration and invasion in glioblastoma (GBM), the most lethal form of primary brain tumors, are critically dependent on Ca2+ signaling. Increases of [Ca2+]i in GBM cells often result from Ca2+ release from the endoplasmic reticulum (ER), promoted by a variety of agents present in the tumor microenvironment and able to activate the phospholipase C/inositol 1,4,5-trisphosphate PLC/IP3 pathway. The Ca2+ signaling is further strengthened by the Ca2+ influx from the extracellular space through Ca2+ release-activated Ca2+ (CRAC) currents sustained by Orai/STIM channels, meant to replenish the partially depleted ER. Notably, the elevated cytosolic [Ca2+]i activates the intermediate conductance Ca2+-activated K (KCa3.1) channels highly expressed in the plasma membrane of GBM cells, and the resulting K+ efflux hyperpolarizes the cell membrane. This translates to an enhancement of Ca2+ entry through Orai/STIM channels as a result of the increased electromotive (driving) force on Ca2+ influx, ending with the establishment of a recurrent cycle reinforcing the Ca2+ signal. Ca2+ signaling in migrating GBM cells often emerges in the form of intracellular Ca2+ oscillations, instrumental to promote key processes in the migratory cycle. This has suggested that KCa3.1 channels may promote GBM cell migration by inducing or modulating the shape of Ca2+ oscillations. In accordance, we recently built a theoretical model of Ca2+ oscillations incorporating the KCa3.1 channel-dependent dynamics of the membrane potential, and found that the KCa3.1 channel activity could significantly affect the IP3 driven Ca2+ oscillations. Here we review our new theoretical model of Ca2+ oscillations in GBM, upgraded in the light of better knowledge of the KCa3.1 channel kinetics and Ca2+ sensitivity, the dynamics of the Orai/STIM channel modulation, the migration and invasion mechanisms of GBM cells, and their regulation by Ca2+ signals.


2020 ◽  
Vol 11 (4) ◽  
pp. 42-63
Author(s):  
Karen Kesler ◽  
Rick Bunch

The purpose of this research was to relate the influence of specific site suitability variables to eastern monarch butterfly migratory patterns and behavior. Elevation, temperature, precipitation, and land use data layers were overlaid to collectively consider how these variables affected the way that butterflies migrated and recolonized during the 2016/2017 migratory cycle. The variables were reclassified into layers ranking suitability as either unsuitable, suitable, or optimal with respective scores of one, three, and five. Three uninhabitable variables were identified that deemed a site unsuitable despite the influence and possible optimal suitability of the other variables. The results of this study indicated that site suitability was a large driving factor for migratory monarchs with a heavier emphasis placed on average temperature and land/cropland use. Possible displaced and sink populations were identified for further study, while the effects of agriculture, development, and climate change were considered regarding flyway connectivity and behavior.


2013 ◽  
Vol 26 (4) ◽  
pp. 333-342 ◽  
Author(s):  
Inês Farias ◽  
Beatriz Morales-Nin ◽  
Pascal Lorance ◽  
Ivone Figueiredo

2005 ◽  
Vol 272 (1572) ◽  
pp. 1547-1555 ◽  
Author(s):  
Michael C James ◽  
Ransom A Myers ◽  
C. Andrea Ottensmeyer

Leatherback sea turtles, Dermochelys coriacea , undertake broad oceanic movements. While satellite telemetry has been used to investigate the post-nesting behaviour of female turtles tagged on tropical nesting beaches, long-term behavioural patterns of turtles of different sexes and sizes have not been described. Here we investigate behaviour for 25 subadult and adult male and female turtles satellite-tagged in temperate waters off Nova Scotia, Canada. Although sex and reproductive condition contributed to variation in migratory patterns, the migratory cycle of all turtles included movement between temperate and tropical waters. Marked changes in rates of travel, and diving and surfacing behaviour, accompanied southward movement away from northern foraging areas. As turtles approached higher latitudes the following spring and summer, they assumed behaviours consistent with regular foraging activity and eventually settled in coastal areas off Canada and the northeastern USA. Behavioural patterns corresponding to various phases of the migratory cycle were consistent across multiple animals and were repeated within individuals that completed return movements to northern waters. We consider the potential biological significance of these patterns, including how turtle behaviour relates to predator avoidance, thermoregulation and prey distribution.


Oikos ◽  
2016 ◽  
Vol 125 (8) ◽  
pp. 1081-1091 ◽  
Author(s):  
Hidetoshi Inamine ◽  
Stephen P. Ellner ◽  
James P. Springer ◽  
Anurag A. Agrawal

2021 ◽  
Author(s):  
◽  
Érika Soares Coelho da Silva

Is poorly known how the diving behavior during the migratory cycle of humpback whales Megaptera novaeangliae is affected by environmental characteristics of their seasonal habitats and their social roles. In this study, archival Argos satellite tags were deployed off the coast of Brazil in 32 humpback whales from the South Western Atlantic Ocean. Tags reported data for ~44 days (max = 124 days) and 92,058 dives. Statistical analysis showed that average dive depth varied between habitats, being shallower in the breeding area (BA, 22.6 m), intermediate during the migration (MI, 30.26 m), and deeper in the feeding area (FA, 35.16 m). The dives classified as deep (>80 m), were more predominant during migration. At FA, dives during the night were shallower and shorter than those performed during the day, at BA dives made during the day were deeper than all other diel phases. We have not found clear differences in dive depth and duration between social classes. The moon phases had a clear effect within BA but not within MI and FA, being shallower at full moon. We also saw that the shapes (U, V, Square), showed differences in dive depth and among habitats. Our data provide the first novel insights into the dive behaviors of individuals from the same population throughout their migratory cycle, performing different diving behaviors, different patterns of social class, shapes, depth range, diel and moon phase. Moreover, these findings and the understanding diving patterns in its drivers have important implications for ecological modelling, conservation policies.


Viruses ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 1205
Author(s):  
Rebecca Poulson ◽  
Deborah Carter ◽  
Shelley Beville ◽  
Lawrence Niles ◽  
Amanda Dey ◽  
...  

Each May for over three decades, avian influenza A viruses (IAVs) have been isolated from shorebirds and gulls (order Charadriiformes) at Delaware Bay (DE Bay), USA, which is a critical stopover site for shorebirds on their spring migration to arctic breeding grounds. At DE Bay, most isolates have been recovered from ruddy turnstones (Arenaria interpres), but it is unknown if this species is involved in either the maintenance or movement of these viruses outside of this site. We collected and tested fecal samples from 2823 ruddy turnstones in Florida and Georgia in the southeastern United States during four winter/spring sample periods—2010, 2011, 2012, and 2013—and during the winters of 2014/2015 and 2015/2016. Twenty-five low pathogenicity IAVs were recovered representing five subtypes (H3N4, H3N8, H5N9, H6N1, and H12N2). Many of these subtypes matched those recovered at DE Bay during the previous year or that year’s migratory cycle, suggesting that IAVs present on these southern wintering areas represent a source of virus introduction to DE Bay via migrating ruddy turnstones. Analyses of all IAV gene segments of H5N9 and H6N1 viruses recovered from ruddy turnstones at DE Bay during May 2012 and from the southeast during the spring of 2012 revealed a high level of genetic relatedness at the nucleotide level, suggesting that migrating ruddy turnstones move IAVs from wintering grounds to the DE Bay ecosystem.


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