MSGID: 1:317/3 6442116b   
   PID: hpt/lnx 1.9.0-cur 2019-01-08   
   TID: hpt/lnx 1.9.0-cur 2019-01-08   
    Hungry eyes: Spiders lose vision when they're starving    
    Findings could improve understanding of how nutrition affects macular   
   degeneration    
      
     Date:   
         April 20, 2023   
     Source:   
         University of Cincinnati   
     Summary:   
         Biologists have discovered that underfed jumping spiders lose light-   
         sensitive cells that are key to their vision.   
      
      
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   FULL STORY   
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   Biologists at the University of Cincinnati discovered that underfed   
   jumping spiders lose light-sensitive cells that are key to their vision.   
      
      
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   UC College of Arts and Sciences Professor Elke Buschbeck and her   
   co-authors studied photoreceptors in the eyes of bold jumping spiders,   
   tiny eight-legged predators found across North America. The little   
   hunters rely on their keen vision to stalk prey.   
      
   But researchers found that underfed spiders begin to lose photoreceptors   
   that give them such good eyesight. Their findings could improve our   
   understanding of the role that nutrition plays in common age-related   
   vision problems such as macular degeneration.   
      
   The study was published in the journal Vision Research.   
      
   Their discovery occurred by serendipity while examining the eyes   
   of wild-caught bold jumping spiders using her lab's custom-made   
   ophthalmoscope, which can take photos of the retinas of insects and   
   spiders. They found dark spots on some of the spiders' photoreceptors,   
   suggesting they had degenerated during its life or development.   
      
   "You could tell just by looking at them that some of the photoreceptors   
   had died," Buschbeck said.   
      
   "But are the photoreceptors really degenerating?" UC doctoral student   
   Shubham Rathore asked. "Or are they just getting bleached by the way we   
   do the experiment?"  Rathore turned to electron microscopy to confirm   
   that the cells indeed were dying.   
      
   The study suggests jumping spiders are a compelling model to study   
   retinal and neuronal health.   
      
   Did poor nutrition cause it?  To test their hypothesis, Miranda Brafford   
   and John Gote', both UC graduates, studied two groups of captive spiders,   
   one fed a normal unrestricted diet and another that was given half   
   portions. In the underfed group, spiders lost more photoreceptors,   
   particularly in the part of the retina that has the highest density   
   of them.   
      
   "It's the functional equivalent of the macula in our eyes," Buschbeck   
   said.   
      
   That is the part of the eye that processes visual information directly   
   in front of you.   
      
   "Photoreceptors are energetically costly. It's hard to keep up with   
   their energy needs," Buschbeck said. "If you deprive them of nutrition,   
   the system fails."  Macular degeneration affects an estimated 20 million   
   people in the United States. It's the most common cause of age-related   
   vision loss and has no cure.   
      
   "What's interesting is macular degeneration in humans also has evidence   
   of being linked to metabolic processes and difficulty with energy being   
   delivered," Buschbeck said.   
      
   Rathore and Buschbeck said they would like to see if the degeneration   
   begins in the support tissues around the photoreceptors and what nutrients   
   in particular support good visual health.   
      
   Study senior author Annette Stowasser, an assistant professor in   
   UC's College of Arts and Sciences, said it's premature to draw direct   
   comparisons between vision deficits in spiders and people.   
      
   "To be able to say anything about how this may inform treatments in   
   people, first carefully designed studies would need to tease out which   
   exact nutrients are involved, which may depend on environmental conditions   
   and other factors," Stowasser said.   
      
   "However, that nutrient deprivation can have the shown effect indicates   
   the importance of paying close attention to the effects of nutrients,"   
   she said.   
      
   Co-author Nathan Morehouse is director of UC's Institute for Research   
   in Sensing and has studied the vision of jumping spiders around the world.   
      
   "Wouldn't it be wild if a breakthrough in macular degeneration treatments   
   for humans was inspired by work on jumping spiders common to back yards   
   across the United States?" said Morehouse, an associate professor in   
   biological sciences.   
      
   "Sometimes answers to challenging problems can come from unexpected   
   places," he said.   
      
   The study was supported by grants from the National Science Foundation.   
      
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   ==========================================================================   
   Story Source: Materials provided by University_of_Cincinnati. Original   
   written by Michael Miller. Note: Content may be edited for style and   
   length.   
      
      
   ==========================================================================   
   Journal Reference:   
      1. Shubham Rathore, John T. Gote', Miranda Brafford, Nathan   
      I. Morehouse,   
         Elke K. Buschbeck, Annette Stowasser. Nutrition-induced   
         macular- degeneration-like photoreceptor damage in jumping   
         spider eyes. Vision Research, 2023; 206: 108185 DOI:   
         10.1016/j.visres.2023.108185   
   ==========================================================================   
      
   Link to news story:   
   https://www.sciencedaily.com/releases/2023/04/230420135311.htm   
      
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