Mobilization of fat body glycogen and haemolymph trehalose under nutritional stress in Bombyx mori larvae in relation to their physiological age and the duration of food deprivation

Kh., Sanathoibi D.; Keshan, Bela

doi:10.2478/s11756-019-00196-0

Cited by 6 publications

(5 citation statements)

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“…period (Kh & Keshan, 2019). In the present study, we show that nutritional stress also leads to an alteration in the transcript levels of neuropeptide genes namely AT, AST-C, and PTTH.…”

Section: Discussionsupporting

confidence: 64%

“…One of the strategies is to regulate the utilization of available nutrients and food reserves. In our previous study, we showed that food deprivation to Bombyx larvae increased the mobilization of carbohydrate reserves such as glycogen in the fat body, depending upon the larval physiological age and the extent of food deprivation period (Kh & Keshan, 2019). In the present study, we show that nutritional stress also leads to an alteration in the transcript levels of neuropeptide genes namely AT , AST‐C , and PTTH .…”

Section: Discussionmentioning

confidence: 99%

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Larval feeding status regulates the transcript levels of genes encoding PTTH and allatoregulatory peptides in silkworm Bombyx mori

Kh.

Keshan

2020

Insect Science

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In Bombyx mori, two dorsolateral neurosecretory cells (NSCs) in each of the two brain lobes have been identified as prothoracicotropic hormone (PTTH) producing cells. This neuropeptide in insects stimulates the prothoracic gland for the synthesis and release of ecdysone, responsible for the molting events. Allatotropin (AT) and allatostatin (AST) are allatoregulatory neuropeptides that regulate juvenile hormone biosynthesis. Here, by using RT-qPCR, we showed that in B. mori, nutritional stress modulates the mRNA expression of AT and AST-C (allatostain type C) in the central nervous system consisting of the brain lobes and all the associated ganglia. Using whole-mount in situ hybridization, we showed that the feeding status of Bombyx larvae also influences the expression of PTTH in the NSCs of the brain. Food deprivation significantly decreased the mRNA expression levels of PTTH in larvae at active or terminal growth period. Further, we showed that insulin modulates the expression level of PTTH. However, its action was dependent on the feeding status of the larvae. At feeding, the insulin decreased the PTTH expression level, while at food deprivation, the insulin increased the PTTH expression level. The data thus indicates that larval feeding status plays an important role in altering the mRNA expression levels of allatoregulatory peptide genes and PTTH.

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“…period (Kh & Keshan, 2019). In the present study, we show that nutritional stress also leads to an alteration in the transcript levels of neuropeptide genes namely AT, AST-C, and PTTH.…”

Section: Discussionsupporting

confidence: 64%

Section: Discussionmentioning

confidence: 99%

Larval feeding status regulates the transcript levels of genes encoding PTTH and allatoregulatory peptides in silkworm Bombyx mori

Kh.

Keshan

2020

Insect Science

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“…TPS has previously been detected and/or quantified in fat bodies of several species ( Cui and Xia, 2009 ; Xu et al, 2009 ; Chen et al, 2010 ; Tang et al, 2010 , 2018 ; Xiong et al, 2019 ; Liu et al, 2020 ) including R. prolixus females, where a transcriptome analysis reveals an up-regulation of this enzyme in the fat body of fed females ( Leyria et al, 2020b ). Interestingly, in R. prolixus , the concentration of trehalose in the fat body and hemolymph is lower than that found in other non-hematophagous species ( Oda et al, 2000 ; Singtripop et al, 2002 ; Moriwaki et al, 2003 ; Michitsch and Steele, 2008 ; Huang et al, 2012 ; Kim and Hong, 2015 ; Kh and Keshan, 2019 ) and, more importantly, it is also lower compared to that found in R. prolixus males ( Mariano et al, 2009 ). There is a peak of trehalose in the fat body of females around 5 days post-blood meal (∼600 pmol/fat body), while in males the maximum trehalose concentration is shown around 5–6 days post-feeding, but in the range of 30–40 nmol/tissue ( Mariano et al, 2009 ).…”

Section: Discussioncontrasting

confidence: 57%

Regulation of a Trehalose-Specific Facilitated Transporter (TRET) by Insulin and Adipokinetic Hormone in Rhodnius prolixus, a Vector of Chagas Disease

et al. 2021

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Using the blood-sucking kissing bug, Rhodnius prolixus as an experimental model, we have studied the involvement of insulin-like peptides (ILPs) and adipokinetic hormone (AKH) signaling in carbohydrate metabolism, focusing on the regulation of the trehalose-specific facilitated transporter (Rhopr-TRET), particularly in the ovaries. We find that trehalose stores in ovaries increase after feeding, synchronously with the beginning of vitellogenesis, but that the transcript expression of enzymes involved in trehalose synthesis show no changes between unfed and blood-fed animals. However, an eightfold increase in Rhopr-TRET transcript expression is observed in the ovaries post-blood meal. In vivo and ex vivo assays using exogenous insulins and Rhopr-AKH, reveal that Rhopr-TRET is up-regulated in ovaries by both peptide families. In accordance with these results, when ILP and AKH signaling cascades are impaired using RNA interference, Rhopr-TRET transcript is down-regulated. In addition, trehalose injection induces an up-regulation of Rhopr-TRET transcript expression and suggests an activation of insulin signaling. Overall, the results support the hypothesis of a direct trehalose uptake by ovaries from the hemolymph through Rhopr-TRET, regulated by ILP and/or AKH. We also show that Rhopr-TRET may work cooperatively with AKH signaling to support the release of trehalose from the ovaries into the hemolymph during the unfed (starved) condition. In conclusion, the results indicate that in females of R. prolixus, trehalose metabolism and its hormonal regulation by ILP and AKH play critical roles in adapting to different nutritional conditions and physiological states.

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“…As reported earlier, at TGP we observe a shift in the glucose flux to glycogen accumulation. [ 21 ] Genes involved in alternate fates of glucose dissemination were downregulated, leading to disturbed glucose flux (Figure 4C).…”

Section: Discussionmentioning

confidence: 99%

Inhibition of Trehalose Synthesis in Lepidoptera Reduces Larval Fitness

Tellis,

Mohite,

Nair

et al. 2023

Advanced Biology

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Trehalose is synthesized in insects through the trehalose 6‐phosphate synthase and phosphatase (TPS/TPP) pathway. TPP dephosphorylates trehalose 6‐phosphate to release trehalose. Trehalose is involved in metamorphosis, but its relation with body weight, size, and developmental timing is unexplored. The expression and activity of TPS/TPP fluctuate depending on trehalose demand. Thus, TPS/TPP inhibition can highlight the significance of trehalose in insect physiology. TPS/TPP transcript levels are elevated in the pre‐pupal and pupal stages in Helicoverpa armigera. The inhibition of recombinantly expressed TPP by N‐(phenylthio)phthalimide (NPP), is validated by in vitro assays. In vivo inhibition of trehalose synthesis reduces larval weight and size, hampers metamorphosis, and reduces its overall fitness. Insufficient trehalose leads to a shift in glucose flux, reduced energy, and dysregulated fatty acid oxidation. Metabolomics reaffirms the depletion of trehalose, glucose, glucose 6‐phosphate, and suppressed tricarboxylic acid cycle. Reduced trehalose hampers the energy level affecting larval vitality. Through trehalose synthesis inhibition, the importance of trehalose in insect physiology and development is investigated. Also, in two other lepidopterans, TPP inhibition impedes physiology and survival. NPP is also found to be effective as an insecticidal formulation. Overall, trehalose levels affect the larval size, weight, and metabolic homeostasis for larval‐pupal transition in lepidoptera.

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Mobilization of fat body glycogen and haemolymph trehalose under nutritional stress in Bombyx mori larvae in relation to their physiological age and the duration of food deprivation

Cited by 6 publications

References 46 publications

Larval feeding status regulates the transcript levels of genes encoding PTTH and allatoregulatory peptides in silkworm Bombyx mori

Larval feeding status regulates the transcript levels of genes encoding PTTH and allatoregulatory peptides in silkworm Bombyx mori

Regulation of a Trehalose-Specific Facilitated Transporter (TRET) by Insulin and Adipokinetic Hormone in Rhodnius prolixus, a Vector of Chagas Disease

Inhibition of Trehalose Synthesis in Lepidoptera Reduces Larval Fitness

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