Photoperiod-modulated instar-specific clock-shifting in the circadian protein and amino acid rhythms in the larval segmental muscle of Bombyx mori

Abstract

Abstract:The photoperiod-modulated clock-shifting in the circadian protein rhythm was studied in the segmental muscle of Bombyx mori. The analysis of phase response curves of the fourth instar rhythm revealed that the muscle tissue completes six protein synthetic cycles (PS cycles) under normal 12 hr light and 12 hr dark cycle (LD), 8 cycles each under continuous light (LL) and continuous dark (DD) conditions. The fifth instar protein rhythm showed seven PS cycles each under LD and DD conditions, but only six under LL. The protein rhythm gets clock-shifted in instarspecific and photoperiod-specific fashions. In the fourth instar, both LL and DD conditions advanced the 24 hr free running time of the rhythm by six hours and set it at 18 hr, but in the fifth instar it is delayed by 4 hr and set at ~28 hr under LL, but remained unchanged under DD. Comparative analysis of protein and amino acid profiles shows that the photoperiod modulates the protein rhythm by altering the rate of amino acid mobilization.

Impact of photoperiod on circadian sucrose and sucrase rhythms in the digestive system of silkworm, Bombyx mori.

“…The glucose moieties so absorbed, are converted to storage carbohydrates, namely, glycogen and trehalose (Thompson and Redak, 2000;Thompson et al, 2001;Thompson et al, 2002). The present study on the circadian profiles of sucrose and sucrase activity confirms that their levels are modulated in a circadian pattern under the impact of light signals , similar to those in other biochemical constituents like proteins, free amino acids, carbohydrates, amylase, trehalose, trehalase and protease in different tissues of B. mori Sivaprasad and Sailaja, 2011;Bhuvaneswari and Sivaprasad, 2012a,b). The circadian sucrose and sucrase data, presented as peaks and troughs in PRC s (Figs.1-4 and Tables 1-6) were analyzed in terms of the number of sucrose synthesis cycles (SS cycles) in the gut wall and number of sucrose uptake cycles (SU cycles) in the gut content.…”

“…Further, the availability of large volume of data on circadian clock mechanism, circadian genes and their products in Drosophila and Bombyx mori (Shimizu et al, 2001;Williams and Sehgal., 2001;Hall, 2003;Sharma, 2003;Satyanarayana et al, 2004;Iwai et al, 2006;Peschel et al, 2009), suggest that many physiological and biochemical processes in insects are under the control of light-sensitive endogenous circadian clocks, that are fine tuned to work in a time schedule of 24 hr (Fonagy, 2009;Hirayama and Sessone-Corsi, 2009). More importantly, the recent reports on circadian physiology of B. mori, emanated from our laboratory Sivaprasad and Sailaja, 2011;Bhuvaneswari and Sivaprasad, 2012a,b) provides impetus for similar investigations. The present study aims at analyzing circadian changes in the profiles of sucrose and sucrase in the digestive system of B. mori under altered photoperiodic conditions.…”

Impact of photoperiod on circadian trehalose and trehalase rhythms in the digestive system of silkworm, Bombyx mori

“…The dynamic equilibrium between trehalose and glucose appears to be maintained by light sensitive time giver in a circadian fashion much like that of many other biochemical constituents (Kostal and Shimada, 2001;Iwai et al, 2006). Our study on the circadian profiles of trehalose and trehalase activity confirms the exsistence of circadian biochemical rhythms in the B. mori, even at the level of digestive system, similar to those in other tissues such as the silk gland, fat body, muscle and haemolymph Sivaprasad, 2010, a, b., Sailaja andSivaprasad and Sailaja, 2011;Bhuvaneswari and Sivaprasad, 2012). The circadian trehalose and trehalase data, presented as peaks and troughs in PRC s (Figs.…”

“…The available data on circadian clock mechanism in Drosophila and B. mori suggests that the physiological and biochemical processes are modulated by endogenous circadian oscillators under the influence of light and dark signals (Naidoo et al, 1999;Giebultowicz, 2001;Shimizu et al, 2001;Froy et al, 2003;Hall, 2003;Sharma, 2003;Sehadova et al, 2004;Iwai et al, 2006;Peschel et al, 2009). This has been demonstrated in our previous reports with reference to some biochemical constituents Sivaprasad, 2010, a, b., Sailaja andSivaprasad and Sailaja, 2011;Bhuvaneswari and Sivaprasad, 2012). However, no effort has since been made to study the impact of photoperiod on the circadian trehalose and trehalase rhythms in the digestive system of B. mori.…”