===Sentinel Cells===

Sentinel cells in Dictyostelium discoideum are phagocytic cells responsible for removing toxic material from the slug stage of the social cycle. Round in shape, these cells are present within the slug sheath where they are found to be circulating freely. The detoxification process occurs when these cells engulf toxins and pathogens within the slug through phagocytosis. Then, the cells clump into groups of five to ten cells, which then attach to the inner sheath of the slug. The sheath is sloughed off as the slug migrates to a new site in search of food bacteria. Sentinel cells make up approximately 1% of the total number of slug cells, and the number of sentinel cells remain constant even as they are being released. This indicates a constant regeneration of sentinel cells within the slugs as they are being removed along with toxins and pathogens. Sentinel cells are present in the slug even if there are no toxins or pathogens to be removed. Sentinel cells have been located in five other species of Dictyostelia, which suggests that sentinel cells can be described as a general characteristic of the innate immune system in social amoebae.[1]

Effects of Farming Status on Sentinel Cells

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The number of sentinel cells varies depending on the farming status of Dictyostelium. Farmers have a fewer number of sentinel cells per millimeter compared to non-farmers. However, the number of sentinel cells does not affect the spore production and viability in farmers. Farmers exposed to a toxic environment produce the same number of spores as the control, and spore viability was the same between the farmers and non-farmers. Thus, it is suggested that bacteria carried by the farmers provide an additional role of protection for the farmers against potential harm due to toxins or pathogens. When Clade 2 Burkholderia, or farmer-associated bacteria, are removed from the farmers, spore production and viability were similar to that of non-farmers.[2]

  1. ^ Chen, Guokai; Zhuchenko, Olga; Kuspa, Adam (2007-08-03). "Immune-like Phagocyte Activity in the Social Amoeba". Science. 317 (5838): 678–681. doi:10.1126/science.1143991. ISSN 0036-8075. PMC 3291017. PMID 17673666.{{cite journal}}: CS1 maint: PMC format (link)
  2. ^ Brock, Debra A.; Callison, W. Éamon; Strassmann, Joan E.; Queller, David C. (2016-04-27). "Sentinel cells, symbiotic bacteria and toxin resistance in the social amoeba Dictyostelium discoideum". Proc. R. Soc. B. 283 (1829): 20152727. doi:10.1098/rspb.2015.2727. ISSN 0962-8452. PMC 4855374. PMID 27097923.{{cite journal}}: CS1 maint: PMC format (link)