Affiliation:
1. College of Life Science, Hebei Normal University, Shijiazhuang, Hebei 050024, China
Abstract
The ratio of RNA to DNA is widely used to reflect instantaneous animal growth; however, little is known about its daily variation. Photoperiod can modify expression of internal clocks, providing animals with the flexibility to adapt to variable environments. This study focused on the influence of photoperiod regimes on the daily variation of RNA:DNA ratio in Pelodiscus sinensis. We randomly divided 260 turtles into four groups: constant dark (0L), 8 h light with 16 h dark (8L), 12 h light with 12 h dark (12L), and 16 h light with 8 h dark (16L). Turtles were housed under specific photoperiods for 15 days (fed for first 10 days then starved for 5 days), thereafter we sampled the tissues every 2 h for 24 h. We dissected forelimb muscles and measured the concentration of isolated RNA and DNA. There were rhythmic variations in the RNA:DNA ratio, even in turtles under continuous darkness, indicating that P. sinensis has circadian RNA:DNA ratio rhythms, and the rhythms were likely controlled by internal clocks. Additionally, the acrophase was advanced by two hours in constant darkness in contrast to the other three photoperiods, indicating that the photoperiod considerably modified the rhythm set by the internal clocks. Notably, the RNA:DNA ratio differed between photoperiod regimes, with 0L > 16L > 8L ≈ 12L, indicating the photoperiod may be a seasonal indicator for turtles to synchronize their physiological processes with environmental variations.
Subject
Animal Science and Zoology,Ecology, Evolution, Behavior and Systematics
Reference39 articles.
1. Physiological responses of dietary tryptophan fed Labeo rohita to temperature and salinity stress;Akhtar;J. Anim. Physiol. Anim. Nutr.,2013
2. Exogenous and endogenous components in circadian rhythms;Aschoff;Cold Spring Harbor Symp. Quant. Biol.,1960
3. Daily expression patterns for mRNAs of GH, PRL, SL, IGF-I and IGF-II in juvenile rabbitfish, Siganus guttatus, during 24-h light and dark cycles;Ayson;Gen. Comp. Endocrinol.,2006
4. Importance of photoperiodic signal quality to entrainment of the circannual reproductive rhythm of the ewe;Barrel;Biol. Reprod.,2000
5. Growth energetics of juvenile herring, Clupea harengus L.: food conversion efficiency and temperature dependency of metabolic rate;Bernreuther;J. Appl. Ichthyol.,2012
Cited by
2 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献