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Full-Text Articles in Life Sciences
Maturation Of Cardiovascular Control Mechanisms In The Embryonic Emu (Dromiceius Novaehollandiae), Dane Crossley, Brian Bagatto, Edward Dzialowski, Warren Burggren
Maturation Of Cardiovascular Control Mechanisms In The Embryonic Emu (Dromiceius Novaehollandiae), Dane Crossley, Brian Bagatto, Edward Dzialowski, Warren Burggren
Brian P. Bagatto
Our understanding of avian embryonic cardiovascular regulation has been based on studies in chickens. The present study was undertaken to determine if the patterns established in chickens are generally applicable to the emu, a ratite bird species. We studied cardiovascular physiology over the interval from 60% to 90% of the emu's 50-day incubation period. During this period, embryonic emus exhibit a slight fall in resting heart rate (from 171 beats min(-1) to 154 beats min(-1)) and a doubling of mean arterial pressure (from 1.2 kPa to 2.6 kPa). Exposures to 15% or 10% O(2) initially decreased heart rate during the …
Two Arabidopsis Circadian Oscillators Can Be Distinguished By Differential Temperature Sensitivity, Todd P. Michael, Patrice A. Salome, C. Robertson Mcclung
Two Arabidopsis Circadian Oscillators Can Be Distinguished By Differential Temperature Sensitivity, Todd P. Michael, Patrice A. Salome, C. Robertson Mcclung
Dartmouth Scholarship
Circadian rhythms are widespread in nature and reflect the activity of an endogenous biological clock. In metazoans, the circadian system includes a central circadian clock in the brain as well as distinct clocks in peripheral tissues such as the retina or liver. Similarly, plants have distinct clocks in different cell layers and tissues. Here, we show that two different circadian clocks, distinguishable by their sensitivity to environmental temperature signals, regulate the transcription of genes that are expressed in the Arabidopsis thaliana cotyledon. One oscillator, which regulates CAB2 expression, responds preferentially to light–dark versus temperature cycles and fails to respond to …
Asymmetry Of The Central Apparatus Defines The Location Of Active Microtubule Sliding In Chlamydomonas Flagella, Matthew J. Wargo, Elizabeth F. Smith
Asymmetry Of The Central Apparatus Defines The Location Of Active Microtubule Sliding In Chlamydomonas Flagella, Matthew J. Wargo, Elizabeth F. Smith
Dartmouth Scholarship
Regulation of ciliary and flagellar motility requires spatial control of dynein-driven microtubule sliding. However, the mechanism for regulating the location and symmetry of dynein activity is not understood. One hypothesis is that the asymmetrically organized central apparatus, through interactions with the radial spokes, transmits a signal to regulate dynein-driven microtubule sliding between subsets of doublet microtubules. Based on this model, we hypothesized that the orientation of the central apparatus defines positions of active microtubule sliding required to control bending in the axoneme. To test this, we induced microtubule sliding in axonemes isolated from wild-type and mutant Chlamydomonas cells, and then …