Bryophytes of the Northern Yukon Territory, Canada, Collected by A. J. Sharp and Others

Brittonia ◽  
1978 ◽  
Vol 30 (2) ◽  
pp. 271 ◽  
Author(s):  
William C. Steere ◽  
George W. Scotter
Keyword(s):  
Yukon Territory

NORTHERN CORDILLERAN ICE SHEET DISPLAYS A DIACHRONOUS RESPONSE TO MIS 4 FORCING, YUKON TERRITORY,CANADA

2019 ◽  
Author(s):  
Brent C. Ward ◽  
◽  
Jeffrey D. Bond ◽  
Derek Cronmiller ◽  
Derek Turner ◽  
...  
Keyword(s):  
Ice Sheet ◽  
Yukon Territory ◽  
Cordilleran Ice Sheet

Interactions of intrinsically disordered Thellungiella salsuginea dehydrins TsDHN-1 and TsDHN-2 with membranes — synergistic effects of lipid composition and temperature on secondary structure

2010 ◽  
Vol 88 (5) ◽  
pp. 791-807 ◽  
Author(s):  
Luna N. Rahman ◽  
Lin Chen ◽  
Sumaiya Nazim ◽  
Vladimir V. Bamm ◽  
Mahmoud W. Yaish ◽  
...  
Keyword(s):  
Secondary Structure ◽  
Synergistic Effects ◽  
Yukon Territory ◽  
Membrane Structures ◽  
Thellungiella Salsuginea ◽  
Intrinsically Disordered ◽  
Induced Folding ◽  
Large Unilamellar Vesicles ◽  
Unstructured Proteins ◽  
Extreme Cold

Dehydrins are intrinsically disordered (unstructured) proteins that are expressed in plants experiencing stressful conditions such as drought or low temperature. Dehydrins are typically found in the cytosol and nucleus, but also associate with chloroplasts, mitochondria, and the plasma membrane. Although their role is not completely understood, it has been suggested that they stabilize proteins or membrane structures during environmental stress, the latter association mediated by formation of amphipathic α-helices by conserved regions called the K-segments. Thellungiella salsuginea is a crucifer that thrives in the Canadian sub-Arctic (Yukon Territory) where it grows on saline-rich soils and experiences periods of both extreme cold and drought. We have cloned and expressed in Escherichia coli two dehydrins from this plant, denoted TsDHN-1 (acidic) and TsDHN-2 (basic). Here, we show using transmission-Fourier transform infrared (FTIR) spectroscopy that ordered secondary structure is induced and stabilized in these proteins by association with large unilamellar vesicles emulating the lipid compositions of plant plasma and organellar membranes. Moreover, this induced folding is enhanced at low temperatures, lending credence to the hypothesis that dehydrins stabilize plant outer and organellar membranes in conditions of cold.

scholarly journals Abrupt glacier motion and reorganization of basal shear stress following the establishment of a connected drainage system

2001 ◽  
Vol 47 (158) ◽  
pp. 472-480 ◽  
Author(s):  
Jeffrey L. Kavanaugh ◽  
Garry K. C. Clarke
Keyword(s):  
Pressure Sensors ◽  
Drainage System ◽  
Yukon Territory ◽  
Stable Configuration ◽  
Drainage Patterns ◽  
Pressure Pulses ◽  
Gradual Failure ◽  
Basal Shear ◽  
Pressure Changes ◽  
Glacier Motion

AbstractThree episodes of strong basal motion occurred at Trapridge Glacier, Yukon Territory, Canada, on 11 June 1995 following the establishment of a connected subglacial drainage system. Responses to these “spring events” are noted in the records for 42 instruments and were recorded throughout the ∼60 000 m2 study area. Strong basal motion during the events is indicated by ploughmeter, load-bolt and vertical-strain records, and abrupt pressure changes in several transducer records denote damage caused by extreme pressure pulses. These pressure pulses, generated by the abrupt basal motion, also resulted in the failure of seven pressure sensors. Records for pressure, turbidity and conductivity sensors indicate that basal drainage patterns did not change significantly during the events. Geophone records suggest that the episodes of basal motion were precipitated by the gradual failure of a “sticky spot” following hydraulic connection of part of the study area. This failure resulted in the transfer of basal stress to the unconnected region of the bed during the course of the events. No evidence for strong basal motion is seen in the instrument records for several weeks following the events, suggesting that the mechanical adjustments resulted in a stable configuration of basal stresses. This event illustrates how unstable situations can be quickly accommodated by mechanical adjustments at the glacier bed.

Life history of tundra-dwelling wolf spiders (Araneae: Lycosidae) from the Yukon Territory, Canada

2012 ◽  
Vol 90 (6) ◽  
pp. 714-721 ◽  
Author(s):  
J.J. Bowden ◽  
C.M. Buddle
Keyword(s):  
Reproductive Effort ◽  
Abiotic Factors ◽  
Wolf Spider ◽  
Local Variation ◽  
Yukon Territory ◽  
The Arctic ◽  
Wolf Spiders ◽  
Female Body Size ◽  
Trade Offs ◽  
History Of

We studied populations of three tundra-dwelling wolf spider (Lycosidae) species to determine reproductive trait relationships and developmental timing in the Arctic. We collected 451 Pardosa lapponica (Thorell, 1872), 176 Pardosa sodalis Holm, 1970, and 117 Pardosa moesta Banks, 1892 during summer 2008. We used log-likelihood ratio tests and multiple linear regressions to determine the best predictors of fecundity and relative reproductive effort. Female body size best explained the variation in fecundity and body condition was the best predictor for relative reproductive effort. We tested for a trade-off between the allocation of resources to individual eggs and the number of eggs produced (fecundity) within each species using linear regression. There was variation in detectable egg size and number trade-offs among sites and these may be related to local variation in resource allocation linked to density-related biotic or abiotic factors. These findings contribute to knowledge about the fitness of arctic wolf spiders in the region of study and are particularly relevant in light of the effects that climate changes are predicted to have on the arctic fauna.

Pleistocene Mammals from Gold Run Creek, Yukon Territory

1973 ◽  
Vol 10 (5) ◽  
pp. 697-759 ◽  
Author(s):  
C. R. Harington ◽  
F. V. Clulow
Keyword(s):  
Yukon Territory ◽  
Radiocarbon Date ◽  
Common Elements ◽  
Radiocarbon Dates ◽  
Equus Asinus ◽  
Wild Ass ◽  
Pleistocene Mammals ◽  
First Time

Remains of thirteen species of mammals are reported from Pleistocene deposits at Gold Run Creek near Dawson, Yukon Territory. Eight of the thirteen species are extinct and two are no longer living in the Yukon. The most common elements of the fauna are Equus (Asinus) lambei (Yukon wild ass), and Bison crassicornis (large-horned bison). Taxidea (badger) and Bison alaskensis (Alaskan bison) are reported for the first time from the Yukon Pleistocene. A kiang-like horse is also reported from deposits at Gold Run Creek.These mammals may have inhabited a cool grassland or open parkland during late Wisconsin time. Bison crassicornis and mammoth bone from deposits at Gold Run Creek have yielded radiocarbon dates of 22 200 ± 1400 yr B.P. and 32 250 ± 1750 yr B.P. respectively. Bison alaskensis is evidently older than the remainder of the fauna as bone from the specimen yielded a radiocarbon date of over 39 900 yr B.P.

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