Characterization of Feeding‐delaying Factors from the Silkworm <i>Bombyx mori</i>

Nagata, Shinji; Morooka, Nobukatsu; Matsumoto, Sumihiro; Nagasawa, Hiromichi

doi:10.1111/j.1749-6632.2009.04454.x

Cited by 7 publications

(3 citation statements)

References 4 publications

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“…Bombyx mori larvae harbour various peptides that regulate feeding behaviour. Some of these peptides are synthesized or recognized in the brain (Nagata et al, 2009(Nagata et al, , 2011a(Nagata et al, , 2011b(Nagata et al, , 2012. Previous studies revealed that BmNPV infection in the brain is crucial for the induction of host manipulation (Katsuma et al, 2012;Kokusho et al, 2015).…”

Section: Discussionmentioning

confidence: 99%

High-resolution analysis of baculovirus-induced host manipulation in the domestic silkworm,Bombyx mori

Hikida

Katsuma

2020

Parasitology

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Many parasites manipulate host behaviour to enhance their transmission. Baculoviruses induce enhanced locomotory activity (ELA) combined with subsequent climbing behaviour in lepidopteran larvae, which facilitates viral dispersal. However, the mechanisms underlying host manipulation system are largely unknown. Previously, larval locomotion during ELA was summarized as the distance travelled for a few minutes at several time points, which are unlikely to characterize ELA precisely, as ELA typically persists for several hours. In this study, we modified a recently developed method using time-lapse recording to characterize locomotion of Bombyx mori larvae infected with B. mori nucleopolyhedrovirus (BmNPV) for 24 h at 3 s resolution. Our data showed that the locomotion of the mock-infected larvae was restricted to a small area, whereas the BmNPV-infected larvae exhibited a large locomotory area. These results indicate that BmNPV dysregulates the locomotory pattern of host larvae. Furthermore, both the mock- and BmNPV-infected larvae showed periodic cycles of movement and stationary behaviour with a similar frequency, suggesting the physiological mechanisms that induce locomotion are unaffected by BmNPV infection. In contrast, the BmNPV-infected larvae exhibited fast and long-lasting locomotion compared with mock-infected larvae, which indicates that locomotory speed and duration are manipulated by BmNPV.

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Section: Discussionmentioning

confidence: 99%

High-resolution analysis of baculovirus-induced host manipulation in the domestic silkworm,Bombyx mori

Hikida

Katsuma

2020

Parasitology

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“…In our previous study, significant feeding inhibitory factors that prolong the latency to the initiation of feeding (feeding-delaying activity) were observed in the extracts of the intestine (foregut, midgut) of B . mori larvae [17]. A previous biochemical study showed that B .…”

Section: Introductionmentioning

confidence: 99%

Enteroendocrine peptides regulate feeding behavior via controlling intestinal contraction of the silkworm Bombyx mori

et al. 2019

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Our previous study demonstrated that predominant feeding inhibitory effects were found in the crude extracts of foregut and midgut of the silkworm Bombyx mori larvae. To address the entero-intestinal control crucial for the regulation of insect feeding behavior, the present study identified and functionally characterized feeding inhibitory peptides from the midgut of B . mori larvae. Purification and structural analyses revealed that the predominant inhibitory factors in the crude extracts were allatotropin (AT) and GSRYamide after its C-terminal sequence. In situ hybridization revealed that AT and GSRYamide were expressed in enteroendocrine cells in the posterior and anterior midgut, respectively. Receptor screening using Ca 2+ -imaging technique showed that the B . mori neuropeptide G protein-coupled receptor (BNGR)-A19 and -A22 acted as GSRYamide receptors and BNGR-A5 acted as an additional AT receptor. Expression analyses of these receptors and the results of the peristaltic motion assay indicated that these peptides participated in the regulation of intestinal contraction. Exposure of pharynx and ileum to AT and GSRYamide inhibited spontaneous contraction in ad libitum -fed larvae, while exposure of pharynx to GSRYamide did not inhibit contraction in non-fed larvae, indicating that the feeding state changed their sensitivity to inhibitory peptides. These different responses corresponded to different expression levels of their receptors in the pharynx. In addition, injection of AT and GSRYamide decreased esophageal contraction frequencies in the melamine-treated transparent larvae. These findings strongly suggest that these peptides exert feeding inhibitory effects by modulating intestinal contraction in response to their feeding state transition, eventually causing feeding termination.

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“…These two physiologically defined feeding states, hunger and satiety, support the evaluation of feeding behavior in B. mori larvae by measuring the latency period prior to the initiation of feeding (Nagata et al, 2011b). We were previously able to identify several biologically active peptides as feeding modulators by measuring the length of the latency period prior to the initiation of feeding in B. mori larvae (Nagata et al, 2009, 2011a,b). Among these peptides, two classes of peptides with different biological activities on feeding behavior were characterized: (1) inhibitory peptides, which prolong the latency to the initiation of feeding, and (2) acceleratory peptides, which shorten the latency to feeding initiation.…”

Section: Introductionmentioning

confidence: 99%

Effects of Starvation on Brain Short Neuropeptide F-1, -2, and -3 Levels and Short Neuropeptide F Receptor Expression Levels of the Silkworm, Bombyx mori

Nagata¹,

Matsumoto²,

Nakane³

et al. 2012

Front. Endocrin.

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In our previous report, we demonstrated the possibility that various regulatory neuropeptides influence feeding behavior in the silkworm, Bombyx mori. Among these feeding-related neuropeptides, short neuropeptide F (sNPF) exhibited feeding-accelerating activity when injected into B. mori larvae. Like other insect sNPFs, the deduced amino acid sequence of the cDNA encoding the sNPF precursor appears to produce multiple sNPF and sNPF-related peptides in B. mori. The presence of three sNPFs, sNPF-1, sNPF-2, and sNPF-3, in the brain of B. mori larvae was confirmed by direct MALDI-TOF mass spectrometric profiling. In addition, all three sNPFs are present in other larval ganglia. The presence of sNPF mRNA in the central nervous system (CNS) was also confirmed by Reverse transcription-polymerase chain reaction. Semi-quantitative analyses of sNPFs in the larval brain using matrix-assisted laser desorption ionization time-of-flight mass spectrometry further revealed that brain sNPF levels decrease in response to starvation, and that they recover with the resumption of feeding. These data suggest that sNPFs were depleted by the starvation process. Furthermore, food deprivation decreased the transcriptional levels of the sNPF receptor (BNGR-A10) in the brain and CNS, suggesting that the sNPF system is dependent on the feeding state of the insect and that the sNPF system may be linked to locomotor activity associated with foraging behavior. Since the injection of sNPFs accelerated the onset of feeding in B. mori larvae, we concluded that sNPFs are strongly related to feeding behavior. In addition, semi-quantitative MS analyses revealed that allatostatin, which is present in the larval brain, is also reduced in response to starvation, whereas the peptide level of Bommyosuppressin was not affected by different feeding states.

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Characterization of Feeding‐delaying Factors from the Silkworm Bombyx mori

Cited by 7 publications

References 4 publications

High-resolution analysis of baculovirus-induced host manipulation in the domestic silkworm,Bombyx mori

High-resolution analysis of baculovirus-induced host manipulation in the domestic silkworm,Bombyx mori

Enteroendocrine peptides regulate feeding behavior via controlling intestinal contraction of the silkworm Bombyx mori

Effects of Starvation on Brain Short Neuropeptide F-1, -2, and -3 Levels and Short Neuropeptide F Receptor Expression Levels of the Silkworm, Bombyx mori

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