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katherine-medina

Effects of experimental increase in insulin-like growth factor 1 on feather growth rate... - 0 views

journals.biologists.com/...ental-increase-in-insulin-like

birds biology HSR2023 insulin plumage feathers molt

shared by katherine-medina on 10 Jul 23 - No Cached
  • In mammals, IGF-1 also induces the proliferation of hair follicles and inhibits apoptosis, and therefore helps to keep them longer in the active (so-called anagen) phase and delay their transition to the regressive (catagen) phase
  • while a recently published study indicated a positive relationship between plumage quality, feather vane length and IGF-1 in a passerine species
  • Detailed quantification of the moulting stage was achieved by scoring the moult of the primary wing feathers and tail feathers on a scale of 0–5, using the standard protocol for recording the progress of feather growth as suggested by the British Trust for Ornithology and further described in
    • katherine-medina
      katherine-medina on 10 Jul 23
       
      I had no idea one could predict when a bird will molt.
  • ...10 more annotations...
  • As a result, 2 weeks after treatment, IGF-1-treated birds were in a more advanced stage of moult than controls
    • katherine-medina
      katherine-medina on 10 Jul 23
       
      Interesting
  • In the longer term, IGF-1 treatment altered the intensity of moult: 2 weeks after treatment, control birds were moulting fewer feathers than at the start of the experiment, while IGF-1-treated birds showed the opposite pattern and increased the number of feathers being moulted simultaneously, albeit with substantial individual variation
  • We manipulated IGF-1 levels using an injection of poly-(lactic-co-glycolid acid) (PLGA) microspheres prepared by S.V.-K. and B.A.G. as described previousl
  • For example, stressors may cause a decrease in circulating IGF-1 levels (Tóth et al., 2018), and it may not be beneficial if that would affect the growth rate or the size of the developing flight feathers.
  • The fact that the growth of the tail feathers was also unaffected by the manipulation is more surprising as they are sexually selected ornaments in this species
    • katherine-medina
      katherine-medina on 10 Jul 23
       
      Wow, I wonder why it had no effect on the growth of the tail feathers.
  • espite the robust lack of effect on feather growth speed, IGF-1 treatment maintained or even increased the number of feathers moulted simultaneously within 2 weeks, while the number of simultaneously growing feathers dropped in controls within the same period
    • katherine-medina
      katherine-medina on 10 Jul 23
       
      Cool
  • In contrast to hair, the number of feather follicles that produce wing and tail feathers is small and shows no variation within species
    • katherine-medina
      katherine-medina on 10 Jul 23
       
      I had no idea.
  • Some species, however, moult several wing and tail feathers simultaneously, which also applies to the bearded reedling
    • katherine-medina
      katherine-medina on 10 Jul 23
       
      Why do some species of birds molt more feathers at the same time than others.
  • . Protein synthesis in tissues, for example, is partly promoted by and regulated through IGF-1 and this might also be of importance during the growth of feathers, in particular considering the increased demand for proteins during moulting
  • The interaction of corticosterone and IGF-1 has been suggested to predict fitness in growing songbirds (Lodjak et al., 2016). Corticosterone levels are known to have a seriously detrimental effect on growing feathers
    • katherine-medina
      katherine-medina on 10 Jul 23
       
      How does corticosterone and IGF-1 interact?
  • katherine-medina on 10 Jul 23
     
    A study about the effect of insulin on the growth of feathers.
lincolnt

Structure and function of bacteriophage T4 - PMC - 0 views

www.ncbi.nlm.nih.gov/...PMC4275845

HSR Phages biology science Bacteria structure T4 head tail tailfiber

shared by lincolnt on 30 May 23 - No Cached
Sean Nash liked it
  • The 194 MDa mature head encapsidates 172 kbp dsDNA, representing 102% of the unique genome [24,25]. The head is first assembled as an empty capsid that is subsequently packaged with DNA by an ATP-dependent packaging machine. This machine binds to the same special pentameric vertex that is later occupied by the phage tail. The head is prolate, meaning that it has two icosahedral ends and a cylindrical mid-section.
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