Deep learning approaches for differentiating thyroid nodules with calcification: a two-center study.

BACKGROUND: Calcification is a common phenomenon in both benign and malignant thyroid nodules. However, the clinical significance of calcification remains unclear. Therefore, we explored a more objective method for distinguishing between benign and malignant thyroid calcified nodules. METHODS: This retrospective study, conducted at two centers, involved a total of 631 thyroid nodules, all of which were pathologically confirmed. Ultrasound image sets were employed for analysis. The primary evaluation index was the area under the receiver-operator characteristic curve (AUROC). We compared the diagnostic performance of deep learning (DL) methods with that of radiologists and determined whether DL could enhance the diagnostic capabilities of radiologists. RESULTS: The Xception classification model exhibited the highest performance, achieving an AUROC of up to 0.970, followed by the DenseNet169 model, which attained an AUROC of up to 0.959. Notably, both DL models outperformed radiologists (P < 0.05). The success of the Xception model can be attributed to its incorporation of deep separable convolution, which effectively reduces the model's parameter count. This feature enables the model to capture features more effectively during the feature extraction process, resulting in superior performance, particularly when dealing with limited data. CONCLUSIONS: This study conclusively demonstrated that DL outperformed radiologists in differentiating between benign and malignant calcified thyroid nodules. Additionally, the diagnostic capabilities of radiologists could be enhanced with the aid of DL.

A Study on the Effect of Energy on the Development of Silkworm Embryos Using an Estrogen-Related Receptor.

Energy metabolism is a fundamental process in all organisms. During silkworm (Bombyx mori) embryonic development, there is a high demand for energy due to continuous cell proliferation and differentiation. Estrogen-related receptors (ERRs) are transcriptional regulatory factors that play crucial roles in mammalian energy storage and expenditure. Although most insects have one ERR gene, it also participates in the regulation of energy metabolism, including carbohydrate metabolism in Drosophila, Aphid, and Silkworm. However, no study has reported the direct impact of energy metabolism on embryonic development in silkworms. In this study, we used transgenic technology to increase silkworm (B. mori; Bm) BmERR expression during embryonic development and explored the impact of energy on embryonic development. We found no significant change in the quality of silkworm eggs compared to that of wild-type silkworms. However, there was an increase in the consumption of vitellin, a major nutrient in embryos. This resulted in a decrease in glucose content and a significant increase in ATP content. These findings provide evidence that the acceleration of energy metabolism promotes embryonic development and enhances the motility of hatched silkworms. In addition, these results provide a novel perspective on the relationship between energy metabolism and embryonic development in other insects.

Estrogen-Related Receptor Influences the Hemolymph Glucose Content by Regulating Midgut Trehalase Gene Expression in the Last Instar Larvae of Bombyx mori.

The expression of trehalase in the midgut of insects plays an important role in glucose supply to the hemolymph. Energy metabolism is usually regulated by the estrogen-related receptor (ERR). A decrease in ATP levels is caused by the ERR hindering glycolysis. However, the relationship between trehalose accumulation and ERR expression is still unclear. Here, we found that silkworm ERR (BmERR) is concentrated and BmERR expression is strongly correlated with trehalase in the midgut during the last instar silkworm larval stage. We cloned the promoter of the trehalase from Bombyx mori (BmTreh) and found that the ERR bound directly to the core response elements of the promoter. Cell level interference and the overexpression of ERR can reduce or enhance BmTreh transcription and promoter activity. Overexpressed transgenic BmERR can significantly increase the expression of BmTreh in the midgut of the last instar silkworm larvae, thereby hydrolyzing trehalose into glucose and releasing it into the hemolymph. Additionally, increased hemolymph glucose content reduces silkworm pupa weight but does not affect silk protein production from the silk gland. Our results suggest a novel function for BmERR through its involvement in BmTreh regulation and expand the understanding of ERR functions in insect trehalose metabolism.

Vitellogenin receptor selectively endocytoses female-specific and highly-expressed hemolymph proteins in the silkworm, Bombyx mori.

VgR, a member of the LDLR family, functions to transport vitellogenin into the ovaries to protome ovarian growth and embryonic development. In insects, the only widely accepted ligand of VgR is Vg. Recently, BmVgR has been shown to interact with BmSP1 in vitro. Therefore, in this study, we evaluated whether BmVgR could transport BmSP1 into certain cells. Although BmVgR could combine with BmVg and BmSP1, BmVgR did not affect the amount of BmSP1 taken up by Sf9 cells. Parallel immunofluorescence showed that most BmVg and BmVgR were localized in the inner oocyte membrane, showing tissue localization similar to that of BmVg labeled with pHrodo Red absorbed by the ovaries on day 2 of pupation. Although BmSP1 showed localization similar to BmVgR during the same phase, little BmSP1 was present in the ovary. Additionally, BmSP1 did not exist in ovaries when the ovaries contained BmVgR on day 5 of pupation, suggesting that BmSP1 in the ovaries was not endocytosed by BmVgR. In summary, BmVgR could facilitate uptake of BmVg by developing oocytes, but did not modulate in the transport of BmSP1.

Real-world video superresolution enhancement method based on the adaptive down-sampling model.

With the 5G and the popularity of high-definition and ultrahigh-definition equipment, people have increasingly higher requirements for the resolution of images or videos. However, the transmission pressure on servers is also gradually increasing. Therefore, superresolution technology has attracted much attention in recent years. Simultaneously, with the further development of deep learning techniques, superresolution research is shifting from the calculation of traditional algorithms to the deep learning method, which exhibits a greatly superior final display. First, the traditional block-matching-3D (BM3D) algorithm is formed as the postprocessing module, which can avoid the uneven edge of GAN network recovery, make the picture appear more authentic, and improve the viewer's subjective feelings. Next, the adaptive-downsampling model (ADM) is utilized to train models for specific camera styles. The high-resolution (HR) data sequence is subsequently downsampled to a low-resolution (LR) data sequence, enabling the superresolution algorithm to utilize this training set. This method can obtain better results and improve overall performance by 0.1~0.3 dB.

Relationships between students' perceived campus walkability, mental health, and life satisfaction during COVID-19.

Improving walkability in the campus environment and socio-psychological environments can promote students' mental health and subjective well-being. This study aimed to propose a theoretical model to investigate the link of perceived campus walkability (PCW) with mental health and life satisfaction (LS), and to disentangle the mediating impact of socio-psychological environments and academic performance on this relationship, while simultaneously considering the effect of the COVID-19 pandemic. We applied structural equation modeling to analyze the data collected through a questionnaire survey conducted at six universities and colleges in Yantai, China. PCW had both direct and indirect positive effects on mental health and LS. However, indirect effects are greater than direct effects. Walking attitudes, social capital, and academic performance were critical to the relationship between PCW, mental health, and LS. Academic performance had the strongest indirect effect on mental health, while social capital had the strongest indirect effect on LS. We also found that during the COVID-19 pandemic, body mass index and family income were significantly correlated with mental health and LS. The findings indicate that campus planners and policymakers should improve PCW and support the socio-psychological environment to promote students' mental and social health during situations like the COVID-19 pandemic.

Silkworm Hemolymph and Cocoon Metabolomics Reveals Valine Improves Feed Efficiency of Silkworm Artificial Diet.

Artificial silkworm diets significantly impact farm profitability. Sustainable cocoon production depends on the continuous improvement of feed efficiency to reduce costs and nutrient losses in the feed. This study used metabolomics to explore the differences in silkworm cocoons and hemolymph under two modes of rearing: an artificial diet and a mulberry-leaf diet. Nine metabolites of silkworm cocoons and hemolymph in the mulberry-leaf group were higher than those in the artificial-diet group. Enrichment analysis of the KEGG pathways for these metabolites revealed that they were mainly enriched in the valine, leucine, and isoleucine biosynthesis and degradation pathways. Hence, the artificial silkworm diet was supplemented various concentrations of valine were supplemented to with the aim of examining the impact of valine on their feeding and digestion of the artificial diet. The results indicated that valine addition had no significant effect on feed digestibility in the fifth-instar silkworm. Food intake in the 2% and 4% valine groups was significantly lower than that in the 0% valine group. However, the 2% and 4% valine groups showed significantly improved cocoon-production efficiency, at 11.3% and 25.1% higher, respectively. However, the cocoon-layer-production efficiencies of the 2% and 4% valine groups decreased by 7.7% and 13.9%, respectively. The research confirmed that valine is an effective substance for enhancing the feed efficiency of silkworms.

Boosting sodium-ion battery performance by anion doping in NASICON Na4MnCr(PO4)3 cathode.

Na superionic conductor (NASICON)-structured Na4MnCr(PO4)3 (NMCP) possessing unique three-electron transfer process renders admirable energy density for sodium ion batteries (SIBs). However, the current issues like its sluggish Na+ diffusion kinetics, deficient intrinsic conductivity, and unsatisfactory structural stability, hinder its practical application. Herein, a selective replacement of O elements in PO4 group by Cl anions in the NMCP system was developed to significantly enhance its electrochemical performance. The results affirm that the enhanced performance of Cl doped samples can be attributed to the enlargement of cell size, the creation of Na vacancies and the weakness of Na2O bond after Cl doping. The as-prepared Na3.85□0.15MnCr(PO3.95Cl0.05)3/C (NMCPC - 15/C) cathode delivers a high capacity (128.0 mAh/g at 50 mA g-1) and excellent rate performance (73.0 mAh/g at 1000 mA g-1) in contrast to NMCP/C that merely provides 105.2 mAh/g at 50 mA g-1 and reduces to 47.4 mAh/g at 1000 mA g-1. Meanwhile, NMCPC - 15/C shows a capacity retention of 60.7 % at 1000 mA g-1 after 500 cycles, while only 37.1 % for NMCP/C in the same test conditions. Moreover, the satisfactory performance and energy density of NMCPC - 15/C||hard carbon (HC) full cell confirm the potential practicality of NMCPC - 15. Therefore, chloride ions doping into NMCP has practical application prospects in the preparation of high-performance cathode materials and our work also offers new inspiration to apply anion doping strategies in promoting the performance of the other NASICON-structured cathodes for SIBs.

Vitellogenin receptor transports the 30K protein LP1 without cell-penetrating peptide, into the oocytes of the silkworm, Bombyx mori.

Vitellogenin receptors (VgRs) transport vitellogenin (Vg) into oocytes, thereby promoting egg growth and embryonic development. VgRs recognize and transport multiple ligands in oviparous animals, but their role in insects is rarely reported. In this study, we investigated whether Bombyx mori VgR (BmVgR) binds and transports lipoprotein-1 (BmLP1) and lipoprotein-7 (BmLP7) of the 30 kDa lipoproteins (30 K proteins), which are essential for egg formation and embryonic development in B. mori. Protein sequence analysis showed BmLP7, similar to reported lipoprotein-3 (BmLP3), contains the cell-penetrating peptides and Cysteine position, while BmLP1 has not. Assays using Spodoptera frugiperda ovary cells (sf9) indicated the direct entry of BmLP7 into the cells, whereas BmLP1 failed to enter. However, co-immunoprecipitation (Co-IP) assays indicated that BmVgR could bind BmLP1. Western blotting and immunofluorescence assays further revealed that over-expressed BmVgR could transport BmLP1 into sf9 cells. Co-IP assays showed that SE11C (comprising LBD1+EGF1+OTC domains of BmVgR) or SE22C (comprising LBD2+EGF2+OTC domains of BmVgR) could bind BmLP1. Over-expressed SE11C or SE22C could also transport BmLP1 into sf9 cells. Western blotting revealed that the ability of SE11C to transport BmLP1 might be stronger than that of SE22C. In the vit mutant with BmVgR gene mutation (vit/vit), SDS-PAGE and western blotting showed the content of BmLP1 in the ovary, like BmVg, was lower than that in the normal silkworm. When transgenic with hsp70 promoter over-expressed BmVgR in the vit mutant, we found that the phenotype of the vit mutant was partly rescued after heat treatment. And contents of BmLP1 and BmVg in vit mutant over-expressed BmVgR were higher than in the vit mutant. We conclude that BmVgR and its two repeat domains could bind and transport BmLP1 into the oocytes of the silkworm, besides BmVg. These results will provide a reference for studying the molecular mechanism of VgR transporting ligands in insects.

Revisiting artificial intelligence diagnosis of hepatocellular carcinoma with DIKWH framework.

Hepatocellular carcinoma (HCC) is the most common type of liver cancer with a high morbidity and fatality rate. Traditional diagnostic methods for HCC are primarily based on clinical presentation, imaging features, and histopathology. With the rapid development of artificial intelligence (AI), which is increasingly used in the diagnosis, treatment, and prognosis prediction of HCC, an automated approach to HCC status classification is promising. AI integrates labeled clinical data, trains on new data of the same type, and performs interpretation tasks. Several studies have shown that AI techniques can help clinicians and radiologists be more efficient and reduce the misdiagnosis rate. However, the coverage of AI technologies leads to difficulty in which the type of AI technology is preferred to choose for a given problem and situation. Solving this concern, it can significantly reduce the time required to determine the required healthcare approach and provide more precise and personalized solutions for different problems. In our review of research work, we summarize existing research works, compare and classify the main results of these according to the specified data, information, knowledge, wisdom (DIKW) framework.

Leveraging deep learning to identify calcification and colloid in thyroid nodules.

Background: Both calcification and colloid in thyroid nodules are reflected as echogenic foci in ultrasound images. However, calcification and colloid have significantly different probabilities of malignancy. We explored the performance of a deep learning (DL) model in distinguishing the echogenic foci of thyroid nodules as calcification or colloid. Methods: We conducted a retrospective study using ultrasound image sets. The DL model was trained and tested on 30,388 images of 1127 nodules. All nodules were pathologically confirmed. The area under the receiver-operator characteristic curve (AUC) was employed as the primary evaluation index. Results: The YoloV5 (You Only Look Once Version 5) transfer learning model for thyroid nodules based on DL detection showed that the average sensitivity, specificity, and accuracy of distinguishing echogenic foci in the test 1 group (n = 192) was 78.41%, 91.36%, and 77.81%, respectively. The average sensitivity, specificity, and accuracy of the three radiologists were 51.14%, 82.58%, and 61.29%, respectively. The average sensitivity, specificity, and accuracy of distinguishing small echogenic foci in the test 2 group (n = 58) was 70.17%, 77.14%, and 73.33%, respectively. Correspondingly, the average sensitivity, specificity, and accuracy of the radiologists were 57.69%, 63.29%, and 59.38%. Conclusions: The study demonstrated that DL performed far better than radiologists in distinguishing echogenic foci of thyroid nodules as calcifications or colloid.

Filling Selenium into Sulfur Vacancies in Ultrathin Tungsten Sulfide Nanosheets for Superior Potassium Storage.

The development of WS2 as an anode for potassium-ion batteries (PIBs) is severely confined by the low K+ storage capacity and poor intrinsic electrical conductivity. Our previous study demonstrated that the creation of sulfur vacancies (VS) in WS2 can enhance its K+ storage capability. However, it is a big challenge to keep the stability of VS while reserving the excellent activity. Herein, we design Se-filled WS2 nanosheets with VS (VS-WS2-Se NS) for PIBs. The Se heteroatom filling into the VS can not only stabilize and activate them, rendering more active sites to adsorb K+, but also further enhance the electrical conductivity. Consequently, the VS-WS2-Se NS anode presents significantly promoted storage capacity and reaction kinetics, superior to the pristine WS2 and WS2 with only VS. Remarkably, the VS-WS2-Se NS anode exhibits the highest specific capacity of 363.9 mA h g-1 at 0.05 A g-1. Simultaneously, a high reversible capacity of 144.2 mA h g-1 after 100 cycles at 2.0 A g-1 is shown. Ex situ analyses demonstrated that the potassium storage mechanism involves the intercalation and conversion reaction between WS2 and K+. Moreover, DFT calculations revealed that the Se filling into VS can further enhance the electrical conductivity and reduce the K-insertion energy barriers of WS2 and thus account for the outstanding electrochemical performance. This study demonstrates that engineering the vacancies by the heteroatom filling strategy offers a novel and feasible route for designing high-performance electrode materials in various energy-storage systems.

Recycling deteriorated silage to remove hazardous mycotoxins and produce a value-added product.

Silage, an important forage feed, contains hazardous mycotoxins due to spoilage caused by unreasonable management. Deteriorated silage becomes a mycotoxin source and threatens human health and the eco-environment. Recycling deteriorated silage and exploiting beneficial substances would be profitable and environmentally friendly. Squalene [60.3-73.9 mg/kg fresh matter (FM)] and 6 types of mycotoxins (4.56-10,080 ug/kg FM) were found in deteriorated silages. To clarify the source and synthesis mechanism of squalene, alfalfa was ensiled at low temperature (LT, 3-20 â„ƒ), 25 â„ƒ (T25), 30 â„ƒ (T30) or 35 â„ƒ (T35) for 10, 40 and 70 d. The highest squalene was detected when alfalfa ensiled for 40 d (P = 0.033) or ensiled at LT and T30 (P < 0.001). Squalene source was traced as lactic acid bacteria (LAB) using next-generation sequencing. Multiple linear regression models inferred that squalene synthase of LAB positively contributed to the squalene synthesis but was negatively adjusted by ammonia-N during ensiling. Two promising squalene-producing LAB strains were screened from alfalfa silage, which fermented deteriorated silage to enhanced squalene yield (190~279 mg/L) with low cost and high mycotoxin removal ratios (up to 85.5%). Therefore, the environmentally friendly strategy of recycling deteriorated silage to produce beneficial squalene was created.

Effects of Microbial Transfer during Food-Gut-Feces Circulation on the Health of Bombyx mori.

Change in habitual diet may negatively affect health. The domestic silkworm (Bombyx mori) is an economically important oligophagous insect that feeds on mulberry leaves. The growth, development, and immune-disease resistance of silkworms have declined under artificial dietary conditions. In this study, we used B. mori as a model insect to explore the relationship between changes in diet and balance of intestinal microbes due to its simpler guts compared with those of mammals. We found that artificial diets reduced the intestinal bacterial diversity in silkworms and resulted in a simple intestinal microbial structure. By analyzing the correlations among food, gut, and fecal microbial diversity, we found that an artificial diet was more easily fermented and enriched the lactic acid bacteria in the gut of the silkworms. This diet caused intestinal acidification and microbial imbalance (dysbiosis). When combined with the artificial diet, Enterococcus mundtii, a colonizing opportunistic pathogen, caused dysbiosis and allowed the frequent outbreak of bacterial diseases in the silkworms. This study provides further systematic indicators and technical references for future investigations of the relationship between diet-based environmental changes and intestinal microbial balance. IMPORTANCE The body often appears unwell after habitual dietary changes. The domestic silkworm (Bombyx mori) raised on artificial diets is a good model to explore the relationship between dietary changes and the balance of intestinal microbes. In this study, the food-gut-feces microbial model was established, and some potential key genera that could regulate the balance of intestinal microbiota were screened out. Our findings will provide a reference for future research to further our understanding of healthy silkworm development and may even be useful for similar research on other animals.

The Response of the Estrogen-Related Receptor to 20-Hydroxyecdysone in Bombyx mori: Insight Into the Function of Estrogen-Related Receptor in Insect 20-Hydroxyecdysone Signaling Pathway.

Estrogen-related receptor (ERR) is an orphan nuclear receptor that was first discovered in animals, and play an important role in metabolism, development, and reproduction. Despite extensive research on the function of ERR, its transcriptional regulation mechanism remains unclear. In this study, we obtained the upstream region of Bombyx mori ERR (BmERR) and confirmed the promoter activity of this region. Interestingly, we found that 10 and 50 nM 20-hydroxyecdysone (20E) up-regulated the transcriptional activity of BmERR promoter. In addition, eight putative ecdysone response elements (EcREs) were predicted in the upstream sequence of BmERR. Based on their positions, the upstream sequence of BmERR was truncated into different fragments. Finally, an EcRE-like sequence (5'-AGTGCAGTAAACTGT-3') was identified. Electrophoretic mobility shift assay (EMSA) and cell transfection experiments confirmed that this motif specifically binds to the complex formed between ecdysone receptor (BmEcR) and the ultraspiracle (BmUSP), a key complex in the 20E signaling pathway. Interference of BmERR or BmEcR mRNA in the embryonic cells of Bombyx mori significantly affected the expression of BmEcR and BmUSP. Overall, these results suggested that an EcRE element was identified from BmERR, and this will help understanding the detailed regulatory mechanism of ERR in insects.

A novel GATA transcription factor GATAß4 promotes vitellogenin transcription and egg formation in the silkworm Bombyx mori.

GATA transcription factors (GATAs) are widely expressed among various organisms and belong to the zinc finger protein family. GATA transcription factors play important roles in the proliferation, differentiation, and development of eukaryotes. Previous studies have shown that GATA participates in oogenesis by selective splicing in silkworms. In this study, we investigated the function of GATAs during vitellogenesis using female silkworms (Bombyx mori). Six types of GATA transcription factors were successfully cloned in the fat body of silkworms during the wandering stage and only BmGATAß4 induced the activity of the Bombyx mori vitellogenin (BmVg) promoter. Furthermore, BmVg and BmGATAß4 exhibited similar expression patterns in the fat body of female silkworms during the wandering stage. Electrophoretic mobility shift assays, cell transfection assays, and chromatin immunoprecipitation showed that BmGATAß4 was involved in regulating the transcription of BmVg by directly binding to the GATA cis-response element 1 (CRE1) and GATA cis-response element 2 (CRE2) in the promoter of the BmVg gene. RNA interference of BmGATAß4 in female silkworms downregulated BmVg transcription, resulting in a decrease in egg size and shortening of the length of egg tubes relative to the control. In summary, our results indicated that BmGATAß4 bound to the GATA CRE1 and CRE2 motifs in the BmVg promoter to upregulate BmVg expression in the fat body of female silkworms.

[Establishment of a suitable control reporter plasmid of a dual luciferase reporter gene system for hormone research in silkworm cell lines].

The dual luciferase reporter gene system provides sensitive readout, while it relies on a constitutively-expressed control gene for readout normalization. However, most standard control reporter genes are not constitutively expressed under all conditions. Here, we report an effective method to construct a control reporter plasmid for the dual luciferase reporter gene system that would be suitable for hormone research in silkworm cell lines. First, we modified BmVgP78M, a stably-expressed constitutive promoter in silkworm cells by mutating its hormone-related element. Then, we constructed the pRL-VgP78M control reporter plasmid by replacing the SV40 promoter and chimeric intron sequences in pRL-SV40 with the BmVgP78M sequence. Finally, we confirmed that the pRL-VgP78M control reporter plasmid could be stably expressed in silkworm cell lines via cell transfection experiments, and it was unresponsive to the induction of ecdysone, juvenile hormone, or their transcription factors. We thus obtained a control reporter plasmid pRL-VgP78M that could be expressed stably and moderately in silkworm cells. It can be readily used as the control reporter plasmid of the dual luciferase reporter gene system for hormone research in silkworm cell lines. It will also provide a reference for construction of control reporter plasmids of dual luciferase reporter gene systems that are adaptable to cell lines isolated from other species.

The expression of ecdysteroid UDP-glucosyltransferase enhances cocoon shell ratio by reducing ecdysteroid titre in last-instar larvae of silkworm, Bombyx mori.

Ecdysteroid UDP glucosyltransferase (EGT) is a baculovirus-encoded protein which can hinder the normal molting of insects by inactivating 20-hydroxyecdysone (20E). Here we expressed EGT in the last-instar silkworm larvae using the GAL4/ UAS system. Compared with the control, for the EGT overexpressed silkworm, the hemolymph 20E content was significantly decreased, the feeding and spinning periods of the last-instar silkworm larvae were extended, the cocoon shell ratio was significantly increased, and the transformation from silkworm larvae to pupa was blocked. Increasing EGT expression resulted in the decrease of 20E content in the hemolymph of silkworm larvae, treating the EGT overexpressed male silkworm with 20E decreased the larval weight and cocoon shell ratio, confirming that the increase in the availability of nutrients to the cocoon and an increase in the cocoon shell weight in the hybrid transgenic silkworms is because of the EGT-induced reduction in active 20E content. Furthermore, though the sericin and flavonoid contents were increased in the cocoon of the EGT overexpressing silkworm, the production of silk fibroin didn't change.

Pigmentary analysis of eggs of the silkworm Bombyx mori.

Ommochromes are major pigments involved in coloration of eggs, eyes, wings, and epidermis of insects. Bombyx mori (silkworm) eggs contain a mixture of ommochrome pigments and their precursors. Here, we analyzed the pigment composition of every egg color strain using egg color mutants (w-2, pe, and re) and wild-type strains (dazao and C108) by using full wavelength scanning and high-performance liquid chromatography. We identified ommochrome pigments and their precursors in pigment extracts from non-diapause eggs and diapause eggs, and found that the quantities of ommochrome precursor 3-hydroxy-kynurenine were much higher in the diapause eggs. Ommochrome pigments were absent in the non-diapause eggs. We analyzed the pigment composition of every egg color strain and found an accumulation of 3-hydroxy-kynurenine and absence of ommochromes in the yellow eggs (w-2 and pe), suggesting that the essential factors for ommochrome biosynthesis are high levels of 3-hydroxy-kynurenine, enzymes for ommochrome synthesis and transferase, and spermatiation. Moreover, we confirmed that both decarboxylated xanthommatin and xanthommatin are major ommochrome pigments, and the quantity of decarboxylated xanthommatin is much higher than that of xanthommatin in silkworm eggs. Since ommochrome pigments can change color under oxidative/reductive conditions and the egg color mutant re turns crimson when preserved at a low temperature for a few weeks, we used an oxidation-reduction reaction in vitro to explore mechanisms behind the pigment-based color change. Specifically, during diapause, the contents of decarboxylated xanthommatin and xanthommatin are increased, and the ommochrome pigments convert into their reduced forms.