Early myogenesis was studied in the offspring of Atlantic salmon (Salmo salar L.) spawning in a lowland (Sheeoch) and an upland (Baddoch) tributary of the River Dee System, Aberdeenshire, Scotland. Eggs from each population were incubated at the simulated natural thermal regimes of each stream, which was on average 2.8 degrees C cooler for the Baddoch than for the Sheeoch. Relationships between muscle cellularity variables, the density of myonuclei and responses to temperature were investigated using multivariate statistical techniques. These revealed highly significant temperature effects (P<0.001) at hatch (H) and first feeding (FF) and significant interactions between population and temperature (P<0.001), indicating that Baddoch and Sheeoch salmon responded differently to the two temperature regimes. The total cross-sectional area of white muscle (WF.ta) at the adipose fin was relatively independent of temperature at hatch and first feeding in the Sheeoch population. In contrast, for alevins of Baddoch origin, WF.ta was 18.9% (H) and 30.5% (FF) higher in fish incubated at Baddoch than at Sheeoch temperatures. At hatch, there were 15.6% more white muscle fibres (WF.no) at the cooler incubation temperature in fish of Sheeoch origin and 6.0% more in fish of Baddoch origin. However, by first feeding, the difference in WF.no between temperatures had narrowed to 7.2% in the Sheeoch fish and increased to 17.4% in the Baddoch population. In contrast, at hatch, the density of myonuclei was 59.8% higher at the warmer incubation temperature in the Sheeoch population and 23.5% higher in the Baddoch population, but differences were less evident at first feeding. In Baddoch fish, 22.5% of the total muscle nuclei were actively dividing at first feeding, as assessed by staining for proliferating cell nuclear antigen (PCNA). Of the PCNA-positive nuclei, 78% were present in cells that stained for the c-met tyrosine kinase receptor, a marker of satellite cells and their division products. The proportion of c-met-positive cells staining for individual myogenic regulatory factors was 72.4% for the myogenic transcription factor MyoD, 76.3% for the myogenic transcription factor Myf-5, 62.1% for myogenin and 48.7% for the myogenic transcription factor Myf-6. For the Sheeoch population, there were 26.5% more c-met-expressing (P<0.01) and 23.2% more myogenic-regulatory-factor-expressing (P<0.05) cells at Sheeoch than at Baddoch temperatures. In contrast, incubation temperature had no significant effects on satellite cell density in the Baddoch population.
Meet the JEB Editors @ SEB 2023
New funding schemes for junior faculty staff
In celebration of our 100th anniversary, JEB has launched two new grants to support junior faculty staff working in animal comparative physiology and biomechanics who are within five years of setting up their first lab/research group. Check out our ECR Visiting Fellowships and Research Partnership Kickstart Travel Grants. First deadline for applications is 15 July 2023.
JEB@100: an interview with Monitoring Editor Katie Gilmour
Katie Gilmour tells us how she first encountered the JEB Editorial team as a graduate student at the University of Cambridge, UK, and how she would like to have a Star Trek tricorder to monitor fish non-invasively in the field.
The Forest of Biologists
The Forest of Biologists is a biodiversity initiative created by The Company of Biologists, with support from the Woodland Trust. For every Research and Review article published in Journal of Experimental Biology a native tree is planted in a UK forest. In addition to this we are protecting and restoring ancient woodland and are dedicating these trees to our peer reviewers. Visit our virtual forest to learn more.
Centenary Review - Adaptive echolocation behavior
Cynthia F. Moss and colleagues discuss the behaviours used by echolocating mammals to track and intercept moving prey, interrogate dynamic sonar scenes, and exploit visual and passive acoustic stimuli.
Crucial DNA at crux of insect wing size evolution
Keity Farfán-Pira and colleagues have revealed that a tiny region of regulatory DNA in the vestigial gene governs whether insect wings are large or small and has played a key role in the evolution of insect wing size.
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