Department of Biology, Pacific University, Forest Grove, Oregon, United States of America.
PLoS One. 2020 Feb 13;15(2):e0228711. doi: 10.1371/journal.pone.0228711. eCollection 2020.
Fasting has been shown to increase longevity and alter immune function in a variety of animals, but little is understood about how reduced caloric intake may impact regeneration and infections in animals that must regularly repair and regenerate tissue in marine environments that contain high levels of bacteria. We examined the possibility that fasting could enhance spine regeneration and reduce bacteremia in the purple sea urchin Strongylocentrotus purpuratus. A small number of spines were removed from urchins and rates of spine regrowth and levels of culturable bacteria from the coelomic fluid were measured for 21 days in fed and fasted urchins. Fasted urchins had higher rates of spine regrowth and lower levels of colony-forming units (CFU) per milliliter of coeolomic fluid. The predominant bacteria in the coelomic fluid was isolated and identified by DNA sequence-based methods as Vibrio cyclitrophicus. After 21 days, fasted and fed urchins were injected with V. cyclitrophicus. Two hours after injection, fed urchins had about 25% more culturable bacteria remaining in their coelomic fluid compared to fasted urchins. We found no evidence that fasting altered coelomic fluid cell number or righting response, indicators of physiologic and behavioral stress in urchins. Our results demonstrate that V. cyclitrophicus is present in purple urchin coelomic fluid, that fasting can increase spine regeneration and that fasted urchins have much lower levels of culturable bacteria in their coelomic fluid than fed urchins. Overall, our data suggests that fasting may ultimately reduce bacteremia and infection in injured or damaged urchins.
禁食已被证明可以延长寿命并改变多种动物的免疫功能，但对于减少卡路里摄入如何影响海洋环境中必须定期修复和再生组织的动物的再生和感染知之甚少，海洋环境中含有高水平的细菌。我们研究了禁食是否可以增强紫海胆 Strongylocentrotus purpuratus 的脊椎再生并减少菌血症的可能性。从海胆中取出少量刺，在喂食和禁食的海胆中测量 21 天内刺的再生率和腔液中可培养细菌的水平。禁食的海胆具有更高的刺再生率和更低的每毫升腔液中的菌落形成单位（CFU）水平。腔液中的主要细菌通过基于 DNA 序列的方法被分离和鉴定为环生柄杆菌（Vibrio cyclitrophicus）。21 天后，将禁食和喂食的海胆注射环生柄杆菌。注射后 2 小时，与禁食的海胆相比，喂食的海胆在其腔液中仍有大约 25%的可培养细菌。我们没有发现禁食会改变腔液细胞数量或定向反应的证据，这些是海胆生理和行为应激的指标。我们的结果表明，环生柄杆菌存在于紫海胆的腔液中，禁食可以增加脊椎再生，并且禁食的海胆的腔液中的可培养细菌水平明显低于喂食的海胆。总的来说，我们的数据表明，禁食可能最终会降低受伤或受损海胆的菌血症和感染率。
