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

Abstract

Abstract:The impact of photoperiod on circadian sucrose and sucrase rhythms were analyzed in the digestive system of Bombyx mori under 12 hr light-dark cycle (LD), continuous light (LL) and continuous dark (DD). The rhythmic changes were interpreted as synthetic cycles in gut wall and release or uptake cycles in gut lumen. The gut wall comprised 6 sucrose synthetic cycles (SS cycles) under LD, LL and 5 under DD. The 24 hr rhythm of LD and LL was clock shifted to 28.8 hr under DD. In gut content, the sucrose rhythm showed 7 sucrose uptake cycles (SU cycles) under LD, 6 under LL and 5 under DD and the 24 hr rhythm of LD was clock shifted to 28.0 hr under LL and 34 hr under DD. In the gut wall sucrase rhythm maintained 7 SES cycles under LD and DD and 9 cycles under LL and its 24-hr rhythm is advanced to 18.2 hr. In the gut lumen 5 SER cycles under LD, 8 under LL and 6 under DD and its rhythm is advanced to 15 hr under LL and 20 hr under DD. Further analysis of data showed that LD favoured both synthesis and uptake of sucrose while LL, favoured the sucrase synthesis and its release.

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

“…Nevertheless, relatively optimal levels (Higher mean peak values) of trehalose (~ 41 mg) were consistently maintained win the gut content under LD compared to those of LL and DD (~ 35 mg each), as in gut wall cells (Table 5). This supports our earlier finding that both light and dark cues are necessary for the maintenance of carbohydrate energy reserves in silkworm tissues, in which such reserves are synthesized in dark phases and predominantly utilized in the light phase of the day (Bhuvaneswari and Sivaprasad, 2012 Circadian trehalase rhythm Gut wall: The gut wall is the primary source of synthesis for two forms of trehalase (Tre-1 and Tre-2) that ensures continuous availability of glucose by enzymatic hydrolysis of trehalose and that meets the energy requirements of peristalsis (Azuma and Yamashita, 1985;Su et al, 1993;Nath, 2000). As demonstrated in the present study, this enzyme rhythm maintains 8 trehalase enzyme synthetic cycles (TES cycles) under LD with a duration of 3.0 hr each, 10 cycles under LL with a duration of 2.4 hr each and 7 cycles under DD with a duration of 3.4 hr each ( Fig.…”

“…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.…”

Effect of spirulina fortification on the digestive protease, carbohydrases and cocoons economic traits of mulberry silkworm Bombyx mori

“…The silkworms identify plants using their keen sense of taste, which enables quality assessment (Tsuneto et al, 2020). The mulberry contains a stimulative compound, a carbohydrate moiety called sucrose, which performs its core duty as a stimulating agent for silkworm feeding (Ito, 1960;Bhuvaneswari et al, 2013). Sucrose often functions as a chemical inducer for feeding behaviour and drives energy cycles in many insect groups.…”