Bombyx batryticatus is a well-known animal in traditional Chinese medicine. The aim of the research was to reveal the quality formation mechanism of B. batryticatus and to screen out the characteristic component used for the quality control. The anticonvulsant effects of B. batryticatus with a stiff time of one, five, and nine days (D1, D5 and D9, respectively) and healthy silkworm of the same developmental stage (SW) were determined by animal experiment. The dynamic changes in chemical composition were analyzed using UPLC-Q-TOF-MS-based metabolomics. D5 and D9 B. batryticatus exhibited significant anticonvulsant effects (p < 0.05 and p < 0.01, respectively). Accordingly, principal component analysis (PCA) and partial least squares discrimination analysis (PLS-DA) indicated that the chemical composition of D5 and D9 B. batryticatus changed significantly. The different metabolites mainly consisted of primary metabolites such as lipids and amino acids and secondary metabolites such as flavonoids, beauvericin, and glycolipids. Interestingly, the relative abundance of quercetin-7-O-β-d-4-O-methylglucoside, the characteristic component of B. batryticatus, increased with stiff time and was promised to be used as an index component of quality control. The results expand our understanding of the quality formation mechanism of B. batryticatus. In addition, it highlights the potential of UPLC-Q-TOF-MS-based metabolomics for the quality control purpose of TCMs.

This study detailed a complete research from Lead (Pb) content level to ecological and health risk to direct- and primary-sources apportionment arising from wheat and rice grains, in the Lihe River Watershed of the Taihu region, East China. Ecological and health risk assessment were based on the pollution index and US Environmental Protection Agency (EPA) health risk assessment model. A three-stage quantitative analysis program based on Pb isotope analysis to determine the relative contributions of primary sources involving (1) direct-source apportionment in grains with a two-end-member model, (2) apportionment of soil and dustfall sources using the IsoSource model, and (3) the integration of results of (1) and (2) was notedly first proposed. The results indicated that mean contents of Pb in wheat and rice grains were 0.54 and 0.45 mg/kg and both the bio-concentration factors (BCF) were <<1; the ecological risk pollution indices were 1.35 for wheat grains and 1.11 for rice grains; hazard quotient (HQ) values for adult and child indicating health risks through ingestion of grains were all <1; Coal-fired industrial sources account for up to 60% of Pb in the grains. This study provides insights into the management of grain Pb pollution and a new method for its source apportionment.

Autophagy is essential for removing damaged organelles and intracellular materials as well as invasive pathogens. The autophagic degradation of intracellular lipids plays a key role in maintaining cellular homeostasis. However, the mechanism of lipid metabolism regulated by autophagy, as well as whether or how lipid metabolites affect autophagy, remain unclear. RNAi of the key autophagy-related (Atg) genes, notably Atg1 and Atg8, suppressed autophagy, while overexpression of these Atg genes facilitated lipid degradation in both Bombyx mori and Drosophila melanogaster. In addition, disrupting autophagosome-lysosome fusion by chloroquine treatment inhibited lipid degradation during both metamorphosis and starvation. LC-MS/MS analysis showed that overexpression of DmAtg1:DmAtg13 mainly degraded glycerolipids, while DmAtg1 mutation predominantly accumulated glycerophospholipids. Notably, the significantly upregulated GPs following autophagy blockage, including C24H50NO7P (LPE, 19:0), C25H52NO7P (LPC, 0:0/17:0), C27H56NO7P (LPC, 0:0/19:0), and C28H58NO7P (LPC, 20:0/0:0), exerted a suppressive effect on autophagy occurrence mainly through the downregulation of AMPK signaling. Autophagosome and autolysosome formations are both critical for lipid degradation. Conversely, the metabolites accumulated due to dysfunctional autophagy inhibit autophagy occurrence by downregulation of AMPK signaling, thereby forming a regulatory loop in insects. Collectively, our results provide valuable insights into applications for beneficial insects and pest management, while also present potential chemicals applied on human diseases related to autophagy or lipid metabolism.

Tip60, a key histone acetyltransferase of the MYST family and member of the nuclear multimeric protein complex (NuA4), regulates the activity and stability of proteins involved in the cell cycle, DNA damage responses, autophagy, etc. However, the function and regulatory mechanism of Tip60 homolog in Bombyx mori are not elucidated. In the present study, Bombyx Tip60 (BmTip60) was functionally identified. Developmental profiles showed that the protein levels and nuclear localization of BmTip60 peaked in fat body during the larval–pupal metamorphosis when autophagy was intensive; simultaneously, the BmTip60 protein migrated to form an upper band as detected by Western blot. Interestingly, the upper band of BmTip60 was reduced by λ-phosphatase treatment, indicating that it was a phosphorylated form of BmTip60. Results showed that BmTip60 was promoted by starvation but not 20-hydroxyecdysone treatment. Transcription factor AMP-activated protein kinase (AMPK) affected by starvation was pivotal for BmTip60 protein migration. In addition, one mammalian phosphorylation site was identified in BmTip60 at Ser99, the constitutive-activation mutation of Ser99 to Asp99 but not its inactive mutation to Ala99 significantly upregulated autophagy, showing the critical role of phosphorylation at Ser99 for BmTip60-mediated autophagy. In conclusion, the starvation-AMPK axis promotes BmTip60 in B. mori, which was requisite for autophagy induction. These results reveal a regulatory mechanism of histone acetyltransferase Tip60 homologs by phosphorylation in insects, and sheds light on further related studies of acetylation regulation.

Conventional immediate and high-temperature immediate acid treatment are crucial techniques for breaking the diapause state of silkworm eggs, but their molecular mechanisms remain unclear. This study prepared diapause eggs (CK), conventional immediate acid-treated eggs (46 °C, 5 min, and CG), and high-temperature immediate acid-treated eggs (47.5 °C, 7 min, and GW) and analyzed the transcriptome and metabolome to screen for key expressed genes and key metabolites. Transcriptome results showed that 688, 823, and 222 differentially expressed genes (DEGs) were obtained from CK vs. CG, CK vs. GW, and CG vs. GW, respectively, and 12 DEGs significantly upregulated in all three comparisons (CK vs. CG, CK vs. GW, and CG vs. GW), including glycine-N-methyltransferase, choline dehydrogenase, Hsp68, and Hsp70. The LC-MS analysis results showed that 854, 711, and 506 differential metabolites (DMs) were obtained from CK vs. CG, CK vs. GW, and CG vs. GW, respectively. A total of seven DMs upregulated in all three comparisons and with |log₂Fold Change| ≥ 0.5 in CG vs. GW, including tyrosine-isoleucine-histidine, phenylalanyl-tyrosine, tyrosine-phenylalanine-glutamate-lysine, and histidylleucine, as well as 12 downregulated DMs, were identified. Additionally, it was found that γ-linolenic acid and triglycerides were upregulated in CG vs. GW. The conjoint analysis results revealed that four small peptides, including tyrosine-isoleucine-histidine, phenylalanyl-tyrosine, tyrosine-phenylalanine-glutamate-lysine, and histidylleucine, exhibited a highly significant positive correlation with Hsp70 family genes such as Hsp68 and Hsp70. This suggests that these small peptides, along with γ-linolenic acid and triglycerides, may play a crucial role in the resistance of silkworm eggs to high-temperature stress and the associated oxidative stress.