A single-cell transcriptomic atlas characterizes the silk-producing organ in the silkworm

Residue-Specific Incorporation of Noncanonical Amino Acids in Auxotrophic Hosts: Quo Vadis?

The residue-specific incorporation of noncanonical amino acids in auxotrophic hosts allows the global exchange of a canonical amino acid with its noncanonical analog. Noncanonical amino acids are not encoded by the standard genetic code, but they carry unique side chain chemistries, e.g., to perform bioorthogonal conjugation reactions or to manipulate the physicochemical properties of a protein such as folding and stability. The method was introduced nearly 70 years ago and is still in widespread use because of its simplicity and robustness. In our study, we review the trends in the field during the last two decades. We give an overview of the application of the method for artificial post-translational protein modifications and the selective functionalization and directed immobilization of proteins. We highlight the trends in the use of noncanonical amino acids for the analysis of nascent proteomes and the engineering of enzymes and biomaterials, and the progress in the biosynthesis of amino acid analogs. We also discuss the challenges for the scale-up of the technique.

Broad complex negatively regulates Fibrohexamerin/P25 by binding to the cis-element BMFA in the silkworm, Bombyx mori

Silk proteins, as natural macromolecular substances, hold significant potential for applications in biomaterials and biomedical fields. The expression of silk protein genes exhibits spatiotemporal specificity. Broad Complex (BrC), a key primary response factor to 20-hydroxyecdysone, plays a crucial role in metamorphosis. Our previous study showed that overexpression of BmBrC-Z2 significantly reduced fibroin gene Fibrohexamerin/P25 expression in the posterior silk gland. However, the underlying regulatory mechanism remains unclear. BMFA, a widely expressed factor that inhibits silk protein gene expression by recognizing BMFA elements, remains unidentified. Notably, the binding sequence of BmBrC-Z2 on the P25 promoter aligns with the BMFA element. Dual-Luciferase Reporter Assays, EMSA, and ChIP-PCR confirmed that BmBrC-Z2 directly binds to the BMFA element, thereby inhibiting P25 promoter activity. Furthermore, we demonstrated that BmBrC-Z2 and its isoform BmBrC-Z4 jointly bind to the BMFA element on the P25 promoter during the molting stage, whereas BmBrC-Z4 contributes a secondary role. Knocking out BmBrC-Z2 using the CRISPR/Cas9 system led to significant upregulation of silk protein genes during the molting stage in mutant larvae. These findings deepen our understanding of the complex regulatory mechanisms governing silk production and highlight the interplay between hormonal signaling and transcriptional regulation.

Knockout of silk fibroin genes in Plutella xylostella results in decreased fitness and performance

BACKGROUND

The ability of insects to spin silk is crucial for their survival, reproduction, and interactions with the environment. The diamondback moth (DBM), Plutella xylostella, a serious agricultural pest, relies on silk production, which influences its behavior and population dynamics.

RESULTS

This study employed CRISPR/Cas9 technology to knock out three genes, that is, silk fibroin heavy chain (PxFibH), silk fibroin light chain (PxFibL), and fibrohexamerin (PxP25), to investigate their roles in silk gland development and related biological traits. We successfully generated PxFibH, PxFibL, and PxP25 knockout mutants, which displayed defective cocoon formation and developed into naked pupae. Further analysis revealed significant alterations in silk gland structure and various biological parameters, including increased larval mortality, prolonged developmental time, reduced pupal weight, and shortened adult lifespan.

CONCLUSIONS

These findings highlight the importance of silk fibroin genes in silk production and growth development in P. xylostella, positioning them as potential targets for innovative pest control strategies. © 2025 Society of Chemical Industry.

BmHR3 Is Essential for Silk Gland Development and Silk Protein Synthesis in Silkworms (Bombyx mori)

The steroid hormone 20-hydroxyecdysone (20E), which is known to regulate insect molting and metamorphosis, is crucial for the normal development of silk glands (SGs) in the silkworm Bombyx mori. However, how the 20E signaling pathway and its core members function in the SG remains largely unclear. Here, we report that the orphan nuclear receptor BmHR3, a 20E-response factor, plays an essential role in regulating SG development and silk protein synthesis. First, we showed that tissue-specific BmHR3 overexpression and knockout result in severe developmental defects in posterior silk glands (PSGs). Second, we revealed that BmHR3 dysfunction in PSGs dramatically represses the transcription of silk fibroin protein-coding genes, thereby inhibiting fibroin protein synthesis. Finally, we confirmed that BmHR3 can regulate fibroin protein-coding gene expression via direct and indirect mechanisms. This study elucidates the vital function of BmHR3 in B. mori SG and provides valuable information for thoroughly understanding the regulatory roles of 20E signaling in specialized insect organs.

BmNPV interacts with super-enhancer regions of the host chromatin to hijack cellular transcription machinery

Effective transcriptional activation relies on the spatial interaction between specific DNA elements. DNA interactions have also been observed between DNA viruses and their hosts, with limited understanding of the involved details. Baculovirus is a representative species of DNA virus and has been reported to interact with the host genome in our previous study. However, the biological significance of the baculovirus-host trans-species DNA interaction and its underlying mechanisms remain elusive. Here, using Bombyx mori nucleopolyhedrovirus (BmNPV) as the model virus, we combine epigenome, transcriptome, and biochemical assays to investigate the baculovirus-host DNA interaction. Our data show that BmNPV hijacks the transcriptional regulatory capacity of host super-enhancers (SEs) by physically interacting with these regions on the host genome. This results in the usurpation of the activating capacity of an SE-binding transcription factor GATA by the virus, thereby impairing the SE-induced specific transcriptional activation of the target antiviral genes. Moreover, the hijacked regulatory capacity is spread on BmNPV genome through cis-interaction of viral DNA, leading to enhanced viral gene expression. Overall, our results provide novel insights into the intricate interplay of viruses with host gene expression regulatory networks and broaden the vision in the mechanisms of viral exploitation on cellular machinery.

SGDAcn is a suppressor for silk gland endoreplication and development

Silkworm silk gland cells undergo multiple rounds of endoreplication, a process in which the genome is duplicated without cell division, leading to cellular polyploidization. This results in the accumulation of genomic DNA, serving as the foundation for rapid silk proteins synthesis. For the first time, we report a previously uncharacterized gene, SGDAcn, in the silkworm silk gland that clustered regularly interspaced short palindromic repeats (CRISPR) / CRISPR-associated nuclease 9-mediated SGDAcn knockout in the posterior silk gland increased cell size and enhanced silk production. SGDAcn knockout facilitated the progression of endoreplication by upregulating the expression of various cyclin genes and promoting energy metabolism, leading to a substantial increase in fibroin gene expression and its transcription factor Dimm, as well as the stimulation of ribosome biogenesis for messenger RNA translation and enhancement of eukaryotic translation initiation factors for protein synthesis. Our findings demonstrate that SGDAcn influences endoreplication, cell growth, and nucleolus size through SGDAcn-EGFR/PI3K/AKT and SGDAcn-NF-κB signaling pathways. Overall, SGDAcn acts as a negative regulator of silk gland development, affecting cell size and protein synthesis, thus modulating silk production. These mechanisms might be conserved in cell growth and progression, making an attractive target for genetic editing to improve silk yield in silkworms and potentially in mammalian cell growth regulation.

Let-7 microRNA targets BmCentrin to modulate the development and functionality of the middle silk gland in the silkworm, Bombyx mori

The silk gland of the silkworm Bombyx mori serves as a valuable model for investigating the morphological structure and physiological functions of organs. Previous studies have demonstrated the notable regulatory role of let-7 microRNA in the silk gland, but its specific molecular mechanism remains to be elucidated across different segments of this organ. In this study, we further investigated the functional mechanism of let-7 in the middle silk gland (MSG). The MSG of a let-7 knockout strain was analyzed using a combined proteomic and metabolomic technique, revealing the enrichment of differential proteins and metabolites in the DNA synthesis and energy metabolism pathways. BmCentrin was identified as a novel target gene of let-7 in the MSG, and its downregulation inhibited the proliferation of BmN4-SID1 cells, which is exactly opposite to the role of let-7 in these cells. CRISPR/Cas9 genome editing and transgenic technologies were employed to manipulate BmCentrin in the MSG. Knockout of BmCentrin led to severe MSG atrophy, whereas the overexpression of BmCentrin resulted in beaded MSG. Further measurements of these knockout or overexpression strains revealed significant changes in the expression levels of sericin protein genes, the weight of the cocoon and the mechanical properties of the silk. Investigating the biological role of BmCentrin in the silk gland offers valuable insights for elucidating the molecular mechanisms by which let-7 controls silk gland development and silk protein synthesis in the silkworm.

β-fructofuranosidase regulation in silkworm silk gland development: Implications for silk gland morphogenesis and silk production

This study investigates the impact of β-fructofuranosidase (Bmsuc1) on the development of the silk gland in silkworms (Bombyx mori). Previous research shows that Bmsuc1 is highly expressed in the silk glands and may be involved in silk gland development and protein synthesis. However, the precise mechanism by which Bmsuc1 regulates silk gland development remains unclear. This study specifically used RNA interference to inhibit Bmsuc1 expression in silkworm larvae. The results revealed that silencing Bmsuc1 led to significant shortening of the anterior silk gland cells, left and right side size asymmetrical development of the middle silk gland, and alterations in cellular and inner membrane layer thickness. Furthermore, the glucose and fructose levels in the silk gland were significantly reduced, reducing cocoon weight. The interference of Bmsuc1 also triggers carbohydrate metabolism-related genes, beta-hexosaminidase subunit (HEXA-β) and glucose-6-phosphatase (G6Pase), which were upregulated. In addition, cell cycle-related genes, Cyclin E and cyclin-dependent kinase 2 (CDK2), were downregulated. These findings provide a new theoretical foundation for understanding the molecular mechanisms of silk gland development and offer insights into improving silk yield.

Single-nucleus RNA sequencing reveals midgut cellular heterogeneity and transcriptional profiles in Bombyx mori cytoplasmic polyhedrosis virus infection

The gut is not only used by insects as an organ for the digestion of food and absorption of nutrients but also as an important barrier against the invasion and proliferation of pathogenic microorganisms. Bombyx mori cytoplasmic polyhedrosis virus (BmCPV), an insect-specific virus, predominantly colonizes the midgut epithelial cells of the silkworm, thereby jeopardizing its normal growth. However, there is limited knowledge of the cellular immune responses to viral infection and whether the infection is promoted or inhibited by different types of cells in the silkworm midgut. In this study, we used single-nucleus RNA sequencing to identify representative enteroendocrine cells, enterocytes, and muscle cell types in the silkworm midgut. In addition, by analyzing the transcriptional profiles of various subpopulations in the infected and uninfected groups, we found that BmCPV infection suppresses the response of the antiviral pathways and induces the expression of BmHSP70, which plays a role in promoting BmCPV replication. However, certain immune genes in the midgut of the silkworm, such as BmLebocin3, were induced upon viral infection, and downregulation of BmLEB3 using RNA interference promoted BmCPV replication in the midgut of B. mori. These results suggest that viral immune evasion and active host resistance coexist in BmCPV-infected silkworms. We reveal the richness of cellular diversity in the midgut of B. mori larvae by single-nucleus RNA sequencing analysis and provide new insights into the complex interactions between the host and the virus at the single-cell level.

Advances in single-cell transcriptomics in animal research

Understanding biological mechanisms is fundamental for improving animal production and health to meet the growing demand for high-quality protein. As an emerging biotechnology, single-cell transcriptomics has been gradually applied in diverse aspects of animal research, offering an effective method to study the gene expression of high-throughput single cells of different tissues/organs in animals. In an unprecedented manner, researchers have identified cell types/subtypes and their marker genes, inferred cellular fate trajectories, and revealed cell‒cell interactions in animals using single-cell transcriptomics. In this paper, we introduce the development of single-cell technology and review the processes, advancements, and applications of single-cell transcriptomics in animal research. We summarize recent efforts using single-cell transcriptomics to obtain a more profound understanding of animal nutrition and health, reproductive performance, genetics, and disease models in different livestock species. Moreover, the practical experience accumulated based on a large number of cases is highlighted to provide a reference for determining key factors (e.g., sample size, cell clustering, and cell type annotation) in single-cell transcriptomics analysis. We also discuss the limitations and outlook of single-cell transcriptomics in the current stage. This paper describes the comprehensive progress of single-cell transcriptomics in animal research, offering novel insights and sustainable advancements in agricultural productivity and animal health.

The architecture of silk-secreting organs during the final larval stage of silkworms revealed by single-nucleus and spatial transcriptomics

Natural silks are renewable proteins with impressive mechanical properties and biocompatibility that are useful in various fields. However, the cellular and spatial organization of silk-secreting organs remains unclear. Here, we combined single-nucleus and spatially resolved transcriptomics to systematically map the cellular and spatial composition of the silk glands (SGs) of mulberry silkworms late in larval development. This approach allowed us to profile SG cell types and cell state dynamics and identify regulatory networks and cell-cell communication related to efficient silk protein synthesis; key markers were validated via transgenic approaches. Notably, we demonstrated the indispensable role of the ecdysone receptor (ultraspiracle) in regulating endoreplication in SG cells. Our atlas presents the results of spatiotemporal analysis of silk-secreting organ architecture late in larval development; this atlas provides a valuable reference for elucidating the mechanism of efficient silk protein synthesis and developing sustainable products made from natural silk.

Single-cell transcriptomics dissecting the development and evolution of nervous system in insects

Insects can display a vast repertoire of complex and adaptive behaviors crucial for survival and reproduction. Yet, how the neural circuits underlying insect behaviors are assembled throughout development and remodeled during evolution remains largely obscure. The advent of single-cell transcriptomics has opened new paths to illuminate these historically intractable questions. Insect behavior is governed by its brain, whose functional complexity is realized through operations across multiple levels, from the molecular and cellular to the circuit and organ. Single-cell transcriptomics enables dissecting brain functions across all these levels and allows tracking regulatory dynamics throughout development and under perturbation. In this review, we mainly focus on the achievements of single-cell transcriptomics in dissecting the molecular and cellular architectures of nervous systems in representative insects, then discuss its applications in tracking the developmental trajectory and functional evolution of insect brains.

Bombyx moriSuppressor of Hairless is involved in the regulation of the silkworm cell cycle and endoreplication of the silk glands

The Notch signaling pathway is important in cell cycle regulation and cell proliferation. The transcriptional repressor Suppressor of Hairless [Su(H)] is a molecular switch for downstream target genes of the Notch signaling pathway but the regulatory mechanism of the Su(H) gene in the cell cycle is unclear. We determined the function of the Notch signaling pathway and Bombyx mori Su(H) [BmSu(H)] in the regulation of the silkworm cell cycle. Inhibition of Notch signaling promoted the replication of DNA in silkworm gland cells and expression of the BmSu(H) gene was significantly reduced. Overexpression of the BmSu(H) gene inhibited DNA replication and cell proliferation of silkworm cells, whereas knockout of the BmSu(H) gene promoted DNA replication and cell proliferation. Knockout of the BmSu(H) in silkworms improved the efficiency of silk gland cell endoreplication and increased important economic traits. We demonstrated that BmSu(H) protein can directly bind to the promoters of BmCyclinA, BmCyclinE and BmCDK1 genes, inhibiting or promoting their transcription at the cell and individual level. This study identified molecular targets for genetic improvement of the silkworm and also provided insights into the regulatory mechanism of the cell cycle.

Deciphering the cellular heterogeneity of the insect brain with single-cell RNA sequencing

Insects show highly complicated adaptive and sophisticated behaviors, including spatial orientation skills, learning ability, and social interaction. These behaviors are controlled by the insect brain, the central part of the nervous system. The tiny insect brain consists of millions of highly differentiated and interconnected cells forming a complex network. Decades of research has gone into an understanding of which parts of the insect brain possess particular behaviors, but exactly how they modulate these functional consequences needs to be clarified. Detailed description of the brain and behavior is required to decipher the complexity of cell types, as well as their connectivity and function. Single-cell RNA-sequencing (scRNA-seq) has emerged recently as a breakthrough technology to understand the transcriptome at cellular resolution. With scRNA-seq, it is possible to uncover the cellular heterogeneity of brain cells and elucidate their specific functions and state. In this review, we first review the basic structure of insect brains and the links to insect behaviors mainly focusing on learning and memory. Then the scRNA applications on insect brains are introduced by representative studies. Single-cell RNA-seq has allowed researchers to classify cell subpopulations within different insect brain regions, pinpoint single-cell developmental trajectories, and identify gene regulatory networks. These developments empower the advances in neuroscience and shed light on the intricate problems in understanding insect brain functions and behaviors.

An efficient and safe strategy for germ cell-specific automatic excision of foreign DNA in F1 hybrid transgenic silkworms

The safety of transgenic technology is a major obstacle in the popularization and use of transgenic silkworms and their products. In sericulture, only the first filial generation (F1 ) hybrid eggs produced by cross-breeding Japanese and Chinese original strains are usually used for the large-scale breeding of silkworms, but this may result in uncontrolled transgene dispersal during the popularization and application of the F1 hybrid transgenic eggs. To address this issue, we developed a safe and efficient strategy using the GAL4/Upstream activating sequence (UAS) system, the FLP/flippase recognition target (FRT) system, and the gonad-specific expression gene promoters (RSHP1p and Nanosp) for the germ cell-specific automatic excision of foreign DNA in the F1 hybrid transgenic silkworms. We established 2 types of activator strains, R1p::GAL4-Gr and Nsp::GAL4-Gr, containing the testis-specific GAL4 gene expression cassettes driven by RSHP1p or Nanosp, respectively, and 1 type of effector strain, UAS::FLP-Rg, containing the UAS-linked FLP gene expression cassette. The FLP recombinase-mediated sperm-specific complete excision of FRT-flanked target DNA in the F1 double-transgenic silkworms resulting from the hybridization of R1p::GAL4-Gr and UAS::FLP-Rg was 100%, whereas the complete excision efficiency resulting from the hybridization of Nsp::GAL4-Gr and UAS::FLP-Rg ranged from 13.73% to 80.3%. Additionally, we identified a gene, sw11114, that is expressed in both testis and ovary of Bombyx mori, and can be used to establish novel gonad-specific expression systems in transgenic silkworms. This strategy has the potential to fundamentally solve the safety issue in the production of F1 transgenic silkworm eggs and provides an important reference for the safety of transgenic technology in other insect species.

SilkMeta: a comprehensive platform for sharing and exploiting pan-genomic and multi-omic silkworm data

The silkworm Bombyx mori is a domesticated insect that serves as an animal model for research and agriculture. The silkworm super-pan-genome dataset, which we published last year, is a unique resource for the study of global genomic diversity and phenotype-genotype association. Here we present SilkMeta (http://silkmeta.org.cn), a comprehensive database covering the available silkworm pan-genome and multi-omics data. The database contains 1082 short-read genomes, 546 long-read assembled genomes, 1168 transcriptomes, 294 phenotype characterizations (phenome), tens of millions of variations (variome), 7253 long non-coding RNAs (lncRNAs), 18 717 full length transcripts and a set of population statistics. We have compiled publications on functional genomics research and genetic stock deciphering (mutant map). A range of bioinformatics tools is also provided for data visualization and retrieval. The large batch of omics data and tools were integrated in twelve functional modules that provide useful strategies and data for comparative and functional genomics research. The interactive bioinformatics platform SilkMeta will benefit not only the silkworm but also the insect biology communities.

GATA binding protein 6 regulates apoptosis in silkworms through interaction with poly (ADP-ribose) polymerase

The GATA family of genes plays various roles in crucial biological processes, such as development, cell differentiation, and disease progression. However, the roles of GATA in insects have not been thoroughly explored. In this study, a genome-wide characterization of the GATA gene family in the silkworm, Bombyx mori, was conducted, revealing lineage-specific expression profiles. Notably, GATA6 is ubiquitously expressed across various developmental stages and tissues, with predominant expression in the midgut, ovaries, and Malpighian tubules. Overexpression of GATA6 inhibits cell growth and promotes apoptosis, whereas, in contrast, knockdown of PARP mitigates the apoptotic effects driven by GATA6 overexpression. Co-immunoprecipitation (co-IP) has demonstrated that GATA6 can interact with Poly (ADP-ribose) polymerase (PARP), suggesting that GATA6 may induce cell apoptosis by activating the enzyme's activity. These findings reveal a dynamic and regulatory relationship between GATA6 and PARP, suggesting a potential role for GATA6 as a key regulator in apoptosis through its interaction with PARP. This research deepens the understanding of the diverse roles of the GATA family in insects, shedding light on new avenues for studies in sericulture and pest management.

Insect Insights at the Single-Cell Level: Technologies and Applications

Single-cell techniques are a promising way to unravel the complexity and heterogeneity of transcripts at the cellular level and to reveal the composition of different cell types and functions in a tissue or organ. In recent years, advances in single-cell RNA sequencing (scRNA-seq) have further changed our view of biological systems. The application of scRNA-seq in insects enables the comprehensive characterization of both common and rare cell types and cell states, the discovery of new cell types, and revealing how cell types relate to each other. The recent application of scRNA-seq techniques to insect tissues has led to a number of exciting discoveries. Here we provide an overview of scRNA-seq and its application in insect research, focusing on biological applications, current challenges, and future opportunities to make new discoveries with scRNA-seq in insects.

Wound Microenvironment Self-Adjusting Hydrogels with Thermo-Sensitivity for Promoting Diabetic Wound Healing

The hard-healing chronic wounds of diabetics are still one of the most intractable problems in clinical skin injury repair. Wound microenvironments directly affect wound healing speed, but conventional dressings exhibit limited efficacy in regulating the wound microenvironment and facilitating healing. To address this serious issue, we designed a thermo-sensitive drug-controlled hydrogel with wound self-adjusting effects, consisting of a sodium alginate (SA), Antheraeapernyi silk gland protein (ASGP) and poly(N-isopropylacrylamide) (PNIPAM) for a self-adjusting microenvironment, resulting in an intelligent releasing drug which promotes skin regeneration. PNIPAM has a benign temperature-sensitive effect. The contraction, drugs and water molecules expulsion of hydrogel were generated upon surpassing lower critical solution temperatures, which made the hydrogel system have smart drug release properties. The addition of ASGP further improves the biocompatibility and endows the thermo-sensitive drug-controlled hydrogel with adhesion. Additionally, in vitro assays demonstrate that the thermo-sensitive drug-controlled hydrogels have good biocompatibility, including the ability to promote the adhesion and proliferation of human skin fibroblast cells. This work proposes an approach for smart drug-controlled hydrogels with a thermo response to promote wound healing by self-adjusting the wound microenvironment.

Dynamic chromatin conformation and accessibility changes mediate the spatial-specific gene regulatory network in Bombyx mori

Silk gland genes of Bombyx mori can have strict spatial expression patterns, which impact their functions and silk quality; however, our understanding of their regulation mechanisms is currently insufficient. To address this, the middle silk gland (MSG) and posterior silk gland (PSG) of the silkworm were investigated. Gene ontology annotation showed that spatially specific expressed genes were involved in the formation of H3k9me and chromatin topology. Chromatin conformation data generated by Hi-C showed that the topologically associated domain boundaries around FibL and Sericin1 genes were significantly different between MSG and PSG. Changes in chromatin conformation led to changes in chromatin activity, which significantly affected the expression of nearby genes in silkworm. Chromatin accessibility regions of MSG and PSG were analyzed using FAIRE-seq, and 1006 transcription factor motifs were identified in open chromatin regions. Furthermore, the spatial-specific expression patterns of silk gland genes were mainly associated with homeobox-contained transcription factors, such as POU-M2, which was specifically bound and relatively highly expressed in the MSG. The regulatory network mediated by POU-M2 regulated most of the spatial-specific expressed genes in MSG, such as ADH1. These results can aid in improving silk performance, optimizing silkworm breeding, and improving the gene spatial regulatory model research for insects.

A molecular atlas reveals the tri-sectional spinning mechanism of spider dragline silk

The process of natural silk production in the spider major ampullate (Ma) gland endows dragline silk with extraordinary mechanical properties and the potential for biomimetic applications. However, the precise genetic roles of the Ma gland during this process remain unknown. Here, we performed a systematic molecular atlas of dragline silk production through a high-quality genome assembly for the golden orb-weaving spider Trichonephila clavata and a multiomics approach to defining the Ma gland tri-sectional architecture: Tail, Sac, and Duct. We uncovered a hierarchical biosynthesis of spidroins, organic acids, lipids, and chitin in the sectionalized Ma gland dedicated to fine silk constitution. The ordered secretion of spidroins was achieved by the synergetic regulation of epigenetic and ceRNA signatures for genomic group-distributed spidroin genes. Single-cellular and spatial RNA profiling identified ten cell types with partitioned functional division determining the tri-sectional organization of the Ma gland. Convergence analysis and genetic manipulation further validated that this tri-sectional architecture of the silk gland was analogous across Arthropoda and inextricably linked with silk formation. Collectively, our study provides multidimensional data that significantly expand the knowledge of spider dragline silk generation and ultimately benefit innovation in spider-inspired fibers.

Attenuation of hexaconazole induced oxidative stress by folic acid, malic acid and ferrocenecarboxaldehyde in an invertebrate model Bombyx mori

Fungicides are a class of pesticides used to ward off fungal diseases from agricultural crops to achieve maximum productivity. These chemicals are quite efficient in controlling diseases; however, the excessive use of these affects non-target organisms as well. In this study, Bombyx mori was utilized to investigate the effect of the pesticide hexaconazole (HEX) on the antioxidant system of this organism and also to find ways to mitigate it. On oral exposure to this chemical, a significant reduction in antioxidants, CAT, GPX, GSH, and SOD in the gut, fat body, and silk gland was observed. The HEX treatment also resulted in lipid peroxidation (LPO) in all the three tissues. To mitigate this toxicity and protect the silkworm from oxidative stress, we tested three compounds, namely folic acid, ferrocenecarboxaldehyde, and malic acid having known antioxidant potential. Folic acid provided significant protection against HEX-induced toxicity. Ferrocenecarboxaldehyde and malic acid proved to be ill-efficient in controlling oxidative stress, with ferrocenecarboxaldehyde being the least effective of the three. Folic acid was also efficient in controlling LPO up to a considerable level. Ferrocenecarboxaldehyde and malic acid also prevented LPO less efficiently than folic acid. Overall folic acid was the only compound that mitigated HEX-induced oxidative stress in silkworm with statistical significance in all the tissues viz. gut, fat body, and silk gland.

A single-cell transcriptomic atlas characterizes the silk-producing organ in the silkworm

The silk gland of the domesticated silkworm Bombyx mori, is a remarkable organ that produces vast amounts of silk with exceptional properties. Little is known about which silk gland cells execute silk protein synthesis and its precise spatiotemporal control. Here, we use single-cell RNA sequencing to build a comprehensive cell atlas of the silkworm silk gland, consisting of 14,972 high-quality cells representing 10 distinct cell types, in three early developmental stages. We annotate all 10 cell types and determine their distributions in each region of the silk gland. Additionally, we decode the developmental trajectory and gene expression status of silk gland cells. Finally, we discover marker genes involved in the regulation of silk gland development and silk protein synthesis. Altogether, this work reveals the heterogeneity of silkworm silk gland cells and their gene expression dynamics, affording a deeper understanding of silk-producing organs at the single-cell level.