Silkworm Bombyx Mori Research Articles

Silkworm (Bombyx mori L.) Has Beneficial Effects on Menopausal Symptoms by Enhancing Estrogen Receptor Signaling in Ovariectomized Mice.

Existing hormone replacement therapy for menopause has drawbacks, necessitating new treatment agents. Silkworms have demonstrated estrogenic properties, offering promising alternatives. We assessed the therapeutic effects of freeze-dried silkworm powder (SWP) on menopausal symptoms using an ovariectomized (OVX) mouse model. The experimental design comprised a sham surgery group (Sham), an OVX control group, a low-dose SWP group post-OVX (80 mg/kg, OVX-SWP-L), a high-dose SWP group post-OVX (160 mg/kg, OVX-SWP-H), and an estradiol treatment group post-OVX (OVX-E2). Treatments were administered orally thrice weekly over eight weeks; body weight was monitored weekly. The SWP-treated groups (SWP-L and SWP-H) exhibited less weight gain and increased uterine thickness than the OVX control. Molecular analyses demonstrated that SWP significantly enhanced the phosphorylation of estrogen receptor alpha (ERα), ERK, and AKT. Furthermore, biochemical assays revealed reduced serum neutral lipids across all SWP treatment groups. Notably, HDL-cholesterol levels were significantly increased in the SWP-L group compared to the OVX group. Serum estradiol concentrations were elevated in all the SWP groups, with significant increases in the high-dose group. These findings indicate that SWP may promote the activation of estrogen receptor signaling and improve symptoms associated with estrogen deficiency during menopause.

Characterization of the UDP-glycosyltransferase UGT33D1 in silkworm Bombyx mori.

Uridine diphosphate (UDP)-glycosyltransferases (UGTs) are important metabolizing enzymes functioning by adding a sugar moiety to a small lipophilic substrate molecule and play critical roles in drug/toxin metabolism for all realms of life. In this study, the silkworm Bombyx mori UGT33D1 gene was characterized in detail. UGT33D1 was found localized in the endoplasmic reticulum (ER) compartment just like other animal UGTs and was mainly expressed in the silkworm midgut. We first reported that UGT33D1 was important to BmNPV infection, as silencing UGT33D1 inhibited the BmNPV infection in silkworm BmN cells, while overexpressing the gene promoted viral infection. The molecular pathways regulated by UGT33D1 were analysed via transcriptome sequencing upon UGT33D1 knockdown, highlighting the important role of the gene in maintaining a balanced oxidoreductive state of the organism. In addition, proteins that physically interact with UGT33D1 were identified through immunoprecipitation and mass spectrometry analysis, which includes tubulin, elongation factor, certain ribosomal proteins, histone proteins and zinc finger proteins that had been previously reported for human UGT-interacting proteins. This study provided preliminary but important functional information on UGT33D1 and is hoped to trigger deeper investigations into silkworm UGTs and their functional mechanisms.

Sustainable production of liquid phenyl using oil extracted from discarded pupae of mulberry silk worms (Bombyx mori)

The mulberry silkworm (Bombyx mori) pupae, typically discarded as waste by the silk industry, are a valuable source of oil. Using the Soxhlet extraction method, 30.4 % oil was recovered from the pulverized dried pupae. This oil exhibited a high iodine value of 120 gI2/100 g and a saponification value of 201 mg KOH/g, which qualified it for soap making in phenyl. Gas Chromatography-Mass Spectrometry (GC-MS) analysis identified five fatty acids in the oil: palmitoleic acid, linoleic acid, oleic acid, stearic acid, and palmitic acid. The composition was 38.80 % saturated fatty acids (SFA), 46.01 % monounsaturated fatty acids (MUFA), and 15.20 % polyunsaturated fatty acids (PUFA). A disinfectant liquid, phenyl, was formulated using this oil, leveraging its high oleic acid content (45.10 %) and favorable physicochemical properties. The antibacterial efficacy of the phenyl was tested against eight harmful bacterial strains. It showed significant activity against all tested bacteria, particularly gram-negative strains, with inhibition zones ranging from 20.25 to 28.0 mm, outperforming the positive control, chloramphenicol, which had inhibition zones of 15.45–19.40 mm. For gram-positive bacteria, the inhibition zones were 14.25–22.50 mm. The phenyl was most effective against Pseudomonas aeruginosa and Escherichia coli, with inhibition zones of 28.0 mm and 23.50 mm, respectively. The minimum inhibitory concentration (MIC) was highest for Pseudomonas aeruginosa and Escherichia coli at 110 μL/mL, and for Staphylococcus aureus at 115 μL/mL. The prepared phenyl disinfectant proved to be efficient against a range of bacteria and can be used to sanitize various surfaces effectively.

Assessment of the performance of silkworm (Bombyx mori L.) on feeding with mulberry raised using different bioagents

Assessment of the performance of silkworm (Bombyx mori L.) on feeding with mulberry raised using different bioagents

Cloning and characterization of the histone variant gene H2A.Z in Bombyx mori.

H2A.Z, the most evolutionarily conserved variant of histone H2A, plays a pivotal role in chromatin remodeling and contributes significantly to gene transcription and genome stability. However, the role of H2A.Z in the silkworm (Bombyx mori) remains unclear. In this study, we cloned the BmH2A.Z from B. mori. The open reading frame of BmH2A.Z is 390 bp, encoding 129 amino acids, with a confirmed molecular weight of 13.4 kDa through prokaryotic expression analysis. Sequence analysis revealed that BmH2A.Z has a conserved H2A.Z domain and is closely related to the systemic evolution of other known H2A.Zs. The expression profile of BmH2A.Z at various developmental stages of the B. mori exhibited the highest expression level in the 1st instar, followed by the grain stage and the 2nd instar, and the lowest expression level in the moth. The highest transcript level of BmH2A.Z was observed in the head, with relatively lower levels detected in the blood than in the other tissues under consideration. In addition, the upregulation of BmH2A.Z resulted in the amplified expression of B. mori nucleopolyhedrovirus (BmNPV) genes, thus facilitating the proliferation of BmNPV. This study establishes a foundation for investigating the role of BmH2A.Z in B. mori and its participation in virus-host interactions.

Mutation in the Bombyx mori BmGMC2 gene impacts silk production and silk protein synthesis

Silk is a natural protein fiber that is predominantly comprised of fibroin and sericin. In addition, it contains seroins, protease inhibitors, enzymes, and other proteins. We found an ecdysone oxidase BmGMC2, notably, which is specifically and highly expressed only in the silk glands of silkworms (Bombyx mori L.). It is also one of the main components of non-cocoon silk, however, its precise function remains unclear. In this study, we examined the spatiotemporal expression pattern of this protein and obtained a homozygous mutant strain (K-GMC2) using the CRISPR-Cas9 system. Compared to the wild-type strain (WT), the silk production and main silk proteins significantly decreased in the larval stage, and the adhesive strength of native silk proteins decreased in the final instar. Proteomic data indicated the abundance of ribosomal proteins decreased significantly in K-GMC2, differentially expressed proteins (DEPs) were enriched in pathways related to neurodegenerative diseases and genetic information processing, indicating that knockout may lead to a certain degree of cell stress, affecting the synthesis of silk proteins. This study investigated the expression pattern and gene function of ecdysone oxidase BmGMC2 in silk and silk glands, laying the groundwork for understanding the role of enzymes in the production of silk fibers.

The Protective Effects of Silkworm (Bombyx mori) Pupae Peptides on UV-Induced Skin Photoaging in Mice.

Silkworm (Bombyx mori) pupae are popular edible insects with high nutritional and therapeutic value. Currently, there is growing interest in the comprehensive application of silkworm pupae. In this study, peptides that exhibited anti-photoaging activity were obtained from silkworm pupae protein, aiming to investigate the protective effects and potential mechanisms of silkworm pupae peptides (SPPs) on skin photoaging. The results showed that SPPs were composed of 900 short peptides and could effectively alleviate skin photoaging progression. They significantly eliminated excessive production of ROS and MDA; meanwhile, they also renovated the antioxidant enzyme activities. The biomarkers related to collagen synthesis and degradation, including hydroxyproline, interstitial collagenase, and gelatinase, demonstrated that SPPs could suppress collagen degradation. Histopathological results showed that SPPs could reduce the inflammatory infiltrate and the thickness of the dermis and epidermis, as well as increase the collagen bundles and muscle fibers. The histopathological and biochemical results confirmed that SPPs could alleviate photoaging by inhibiting abnormal skin changes, reducing oxidative stress, and immune suppression. Overall, these data prove the protective effects of SPPs against the photoaging process, suggesting their potential as an active ingredient in skin photoaging prevention and therapy.

Preparation of Autoclavable and Injectable Silk Fibroin Cryogels for Tissue Engineering Applications.

A cryogel is a supermacroporous gel network that is generated at subzero temperatures by polymerizing monomers or gelating polymeric precursors. Since cryogels possess inherent characteristics such asinterconnectedmacroporous structures, excellent mechanical properties,and high resistanceto autoclave sterilization,they are highly desirable for tissue engineering and regenerative medicine. Silk fibroin, a natural protein obtainedfrom Bombyx morisilkworms, is an excellent raw material for cryogel preparation. The aim of this study is toestablish acontrolled method for preparing silk fibroincryogels with suitable properties for application as tissue engineering scaffolds. Using a dual crosslinking strategy consisting of low-temperature radical polymerization coupled with methanol-induced conformational transformation, porous cryogels are prepared. The cryogelsdisplay many unique characteristics, such as an interconnected macroporous structure, a high water absorption capacity, water-triggered shape memory, syringe injectability, and strong resilience to autoclave sterilization. Furthermore, the cryogels demonstrate excellent biocompatibility and cell affinity, facilitating cell adhesion, migration, andproliferation. The interconnected supermacroporous architecture resembling the nativeextracellular matrix, together with their unique physical properties and autoclaving stability, suggests that cryogels are promising candidate scaffolds for tissue engineering and cell therapy.

Enhanced sensitivity of chimeric insect olfactory co-receptors for detecting odorant molecules

Insect olfactory receptors (ORs) are seven-transmembrane domain ion channels that function by forming heteromeric complexes with olfactory receptor co-receptors (Orcos). In this study, we investigated the potential for enhancing sensitivity of odor detection and responsivity through genetic modification of Orcos, considering its wider application in odor sensing. First, we measured the intensity of response to 1-octen-3-ol for the mosquito Aedes aegypti OR (AaOR8) when complexed individually with an Orco from the same mosquito (AaOrco), the honeybee Apis mellifera (AmOrco), the silkworm Bombyx mori (BmOrco), or the fruit fly Drosophila melanogaster (DmOrco). Relative to the other Orcos, AmOrco demonstrated higher sensitivity and responsivity, with a 1.8 to 21-fold decrease in the half-maximal effective concentration (EC50) and a 1.6–8.8-fold increase in the maximal effect (Emax), respectively. Furthermore, AmOrco co-expressed with AaOR10, BmOR56, or DmOR47a showed higher sensitivity and responsivity than AaOrco, BmOrco, or DmOrco co-expressed with their respective ORs. To further increase sensitivity and responsivity, we engineered chimeric Orcos by fusing AmOrco with DmOrco, considering the domain characteristics of Orcos. The response to 1-octen-3-ol was evaluated for AaOR8 when complexed individually with AmOrco, as well as for a mutant that combines DmOrco from the N-terminal (NT) to the C-terminal region of the fourth transmembrane domain (TM4) with the region of AmOrco following TM4 (Dm[NT-TM4]AmOrco). When compared to AmOrco, Dm(NT-TM4)AmOrco showed higher sensitivity and responsivity, with a 1.4-fold decrease in the EC50 and a 1.4-fold increase in the Emax, respectively. In addition, Dm(NT-TM4)AmOrco co-expressed with either DmOR47a or BmOR56 demonstrated higher sensitivity and responsivity than AmOrco co-expressed with their respective ORs. These results suggest that AmOrco could be a relatively more sensitive Orco, and further enhancement of sensitivity and responsivity could be achieved through recombination with heterologous Orcos near the TM4 of AmOrco.

Effect of acute exposure of Hg on physiological parameters and transcriptome expression in silkworms (Bombyx mori).

Mercury (Hg) contamination poses a global threat to the environment, given its elevated ecotoxicity. Herein, we employed the lepidopteran model insect, silkworm (Bombyx mori), to systematically investigate the toxic effects of Hg-stress across its growth and development, histomorphology, antioxidant enzyme activities, and transcriptome responses. High doses of Hg exposure induced evident poisoning symptoms, markedly impeding the growth of silkworm larvae and escalating mortality in a dose-dependent manner. Under Hg exposure, the histomorphology of both the midgut and fat body exhibited impairments. Carboxylesterase (CarE) activity was increased in both midgut and fat body tissues responding to Hg treatment. Conversely, glutathione S-transferase (GST) levels increased in the fat body but decreased in the midgut. The transcriptomic analysis revealed that the response induced by Hg stress involved multiple metabolism processes. Significantly differently expressed genes (DEGs) exhibited strong associations with oxidative phosphorylation, nutrient metabolisms, insect hormone biosynthesis, lysosome, ribosome biogenesis in eukaryotes, and ribosome pathways in the midgut or the fat body. The findings implied that exposure to Hg might induce the oxidative stress response, attempting to compensate for impaired metabolism. Concurrently, disruptions in nutrient metabolism and insect hormone activity might hinder growth and development, leading to immune dysfunction in silkworms. These insights significantly advance our theoretical understanding of the potential mechanisms underlying Hg toxicity in invertebrate organisms.

Comparative analysis of testicular fusion in Spodoptera litura (cutworm) and Bombyx mori (silkworm): Histological and transcriptomic insights

Spodoptera litura commonly known as the cutworm, is among the most destructive lepidopteran pests affecting over 120 plants species. The powerful destructive nature of this lepidopteran is attributable to its high reproductive capacity. The testicular fusion that occurs during metamorphosis from larvae to pupa in S.litura positively influences the reproductive success of the offspring. In contrast, Bombyx mori, the silkworm, retains separate testes throughout its life and does not undergo this fusion process. Microscopic examination reveals that during testicular fusion in S.litura, the peritoneal sheath becomes thinner and more translucent, whereas in B.mori, the analogous region thickens. The outer basement membrane in S.litura exhibits fractures, discontinuity, and uneven thickness accompanied by a significant presence of cellular secretions, large cell size, increased vesicles, liquid droplets, and a proliferation of rough endoplasmic reticulum and mitochondria. In contrast, the testicular peritoneal sheath of B.mori at comparable developmental stage exhibits minimal change. Comparative transcriptomic analysis of the testicular peritoneal sheath reveals a substantial difference in gene expression between the two species. The disparity in differential expressed genes (DEGs) is linked to an enrichment of numerous transcription factors, intracellular signaling pathways involving Ca2+ and GTPase, as well as intracellular protein transport and signaling pathways. Meanwhile, structural proteins including actin, chitin-binding proteins, membrane protein fractions, cell adhesion, extracellular matrix proteins are predominantly identified. Moreover, the study highlights the enrichment of endopeptidases, serine proteases, proteolytic enzymes and matrix metalloproteins, which may play a role in the degradation of the outer membrane. Five transcription factors-Slforkhead, Slproline, Slcyclic, Slsilk, and SlD-ETS were identified, and their expression pattern were confirmed by qRT-PCR. they are candidates for participating in the regulation of testicular fusion. Our findings underscore significant morphological and trancriptomic variation in the testicular peritoneal sheath of S.litura compared to the silkworm, with substantial changes at the transcriptomic level coinciding with testicular fusion. The research provides valuable clues for understanding the complex mechanisms underlying this unique phenomenon in insects.

Fatty Acid Profile and Thermal Behavior of Fat-Rich Edible Insect Oils Compared to Commonly Consumed Animal and Plant Oils.

This study compared the physicochemical properties of edible insect oils from silkworm (Bombyx mori) pupa (SP), sago palm weevil (Rhynchophorus ferrugineus) larva (PW), and bamboo caterpillar (Omphisa fuscidentalis; BC) to oils from chicken skin (CK), beef back fat (BF), pork back fat (PF), salmon belly (SB), sea bass belly (BB), coconut (C), and peanut (P). The fatty acid profiles and thermal behaviors (crystallization and melting) of the extracted oils were evaluated. PW and BC oils had more saturated fatty acids (SFAs) than CK, PF, SB, BB, and P oils. SP oil had equivalent SFA content to CK and BB oils. Insect oils exhibited similar monounsaturated fatty acid concentrations in all samples, except C oils. PW and BC oils exhibited a higher content of palmitoleic acid than the other oils. SP oils contained polyunsaturated fatty acids similar to those in SB and BB oils, which were higher than those in PW, BC, CK, BF, and PF oils. SP oil also exhibited the highest concentration of α-linolenic acid (C18:3 n-3). Arachidonic acid (0.01-0.02 g/100 g) in all insect oils was lower level compared to CK, BF, PF, SB, and BB oils. SP oil (0.03 g/100 g) exhibited a slightly higher level of eicosapentaenoic acid compared to PW (0.01 g/100 g) and BC (0.01 g/100 g) oils. The insect oils were liquid at ambient temperature, solid below -15°C, and required less energy (△Hm-max) for melting than other samples. This study indicated that insects, particularly SP, could serve as an alternative source of fat to meet its growing demand.

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.

MIG1, TUP1 and NRG1 mediated yeast to hyphal morphogenesis inhibition in Candida albicans by ganciclovir.

Candida albicans is a polymorphic human fungal pathogen and the prime etiological agent responsible for candidiasis. The main two aspects of C. albicans virulence that have been suggested are yeast-to-hyphal (Y-H) morphological transitions and biofilm development. Anti-fungal agents targeting these virulence attributes enhances the antifungal drug development process. Repositioning with other non-fungal drugs offered a one of the new strategies and a potential alternative option to counter the urgent need for antifungal drug development. In the current study, an antiviral drug ganciclovir was screened as an antifungal agent against ATCC 90028, 10231 and clinical isolate (C1). Ganciclovir at 0.5mg/ml concentration reduced 50% hyphal development on a silicon-based urinary catheter and was visualized using scanning electron microscopy. Ganciclovir reduced ergosterol biosynthesis in both strains and C1 isolate of C. albicans in a concentration-dependent manner. Additionally, a gene expression profile study showed that ganciclovir treatment resulted in upregulation of hyphal-specific repressors MIG1, TUP1, and NRG1 in C. albicans. Additionally, an in vivo study on the Bombyx mori silkworm model further evidenced the virulence inhibitory ability of ganciclovir (0.5mg/ml) against C. albicans. This is the first report that explore the novel anti-morphogenic activities of ganciclovir against the pathogenic C. albicans strains, along with clinical isolates. Further, ganciclovir may be considered for therapeutic purpose after combinations with standard antifungal agents.

The mechanoreceptor Piezo is required for spermatogenesis in Bombyx mori

BackgroundThe animal sperm shows high diversity in morphology, components, and motility. In the lepidopteran model insect, the silkworm Bombyx mori, two types of sperm, including nucleate fertile eupyrene sperm and anucleate unfertile apyrene sperm, are generated. Apyrene sperm assists fertilization by facilitating the migration of eupyrene spermatozoa from the bursa copulatrix to the spermatheca. During spermatogenesis, eupyrene sperm bundles extrude the cytoplasm by peristaltic squeezing, while the nuclei of the apyrene sperm bundles are discarded with the same process, forming matured sperm.ResultsIn this study, we describe that a mechanoreceptor BmPiezo, the sole Piezo ortholog in B. mori, plays key roles in larval feeding behavior and, more importantly, is essential for eupyrene spermatogenesis and male fertility. CRISPR/Cas9-mediated loss of BmPiezo function decreases larval appetite and subsequent body size and weight. Immunofluorescence analyses reveal that BmPiezo is intensely localized in the inflatable point of eupyrene sperm bundle induced by peristaltic squeezing. BmPiezo is also enriched in the middle region of apyrene sperm bundle before peristaltic squeezing. Cytological analyses of dimorphic sperm reveal developmental arrest of eupyrene sperm bundles in BmPiezo mutants, while the apyrene spermatogenesis is not affected. RNA-seq analysis and q-RT-PCR analyses demonstrate that eupyrene spermatogenic arrest is associated with the dysregulation of the actin cytoskeleton. Moreover, we show that the deformed eupyrene sperm bundles fail to migrate from the testes, resulting in male infertility due to the absence of eupyrene sperm in the bursa copulatrix and spermatheca.ConclusionsIn conclusion, our studies thus uncover a new role for Piezo in regulating spermatogenesis and male fertility in insects.

Biosynthesis of Pteridines in Insects: A Review

Pteridines are important cofactors for many biological functions of all living organisms, and they were first discovered as pigments of insects, mainly in butterfly wings and the eye and body colors of insects. Most of the information on their structures and biosynthesis has been obtained from studies with the model insects Drosophila melanogaster and the silkworm Bombyx mori. This review discusses, and integrates into one metabolic pathway, the different branches which lead to the synthesis of the red pigments “drosopterins”, the yellow pigments sepiapterin and sepialumazine, the orange pigment erythropterin and its related yellow metabolites (xanthopterin and 7-methyl-xanthopterin), the colorless compounds with violet fluorescence (isoxanthopterin and isoxantholumazine), and the branch leading to tetrahydrobiopterin, the essential cofactor for the synthesis of aromatic amino acids and biogenic amines.

Cocoon Care : Transformative Monitoring For Sericulture

Sericulture is the process of cultivating silkworms and extracting silk from them. The caterpillars of the domestic silk moth (also called „Bombyx Mori‟) are the most commonly used silkworm species in sericulture. Other types of silkworms (such as Eri, Muga, and Tasar) are also cultivated for the production of „wild silks‟. Silk is known as the queen of textiles due to its softness, durability, and luster. Furthermore, the silk fibers provide characteristics that are superior toany other type of fiber (e.g., water absorbency, heat resistance, dyeing efficiency, and luster). This textile is obtained from cocoons spun by larvae known as silkworm (Bombyx mori), which were discovered in China between 2600 and 2700 BC. The process of silk production is known as sericulture, beginning with the rearing of the silkworm1

Improvement of Silkworm (Bombyx mori L.) Growth and Cocoon Quality Using Nickel Sulfate Supplementation

The silkworm belongs to the order Lepidoptera and the family Bombycidae (Bombyx mori L.). The silkworm industry plays a crucial role in providing employment opportunities in India. This study investigated the effects of nickel sulfate supplementation on the growth and cocoon quality of silkworm (Bombyx mori L.). The experiment was conducted at a silkworm-rearing center in Palayamkottai, India, from December 2022 to January 2023. Silkworms were fed Victory-1 (V1) mulberry leaves soaked in different nickel sulfate solutions (100 ppm, 300 ppm, and 500 ppm). Larval weight, duration, cocoon weight, shell weight, shell ratio, and pupal weight were measured for 10 healthy silkworms with good quality cocoons selected from each treatment group. Compared to the control group, supplementation with 500-ppm nickel sulfate solution significantly improved silkworm growth performance (weight) and economic traits (cocoon weight and quality). GRAPHICAL ABSTRACT

Impact of Surface Functionality on Biodistribution of Gold Nanoparticles in Silkworms

To date, animal models are still indispensable for studying biodistribution and elimination of nanomaterials. However, the use of mammals for in vivo experiments faces various challenges including increasing regulatory hurdles and costs. This study aims to validate larvae of the domestic silkworm Bombyx mori as an alternative invertebrate model for preliminary in vivo research. Organ distribution and elimination of gold nanoparticles (AuNPs) are compared with four different surface functionalities in silkworms after systemic administration: AuNPs coated with poly(ethylene glycol) (PEG), with polyglycidols (PGs) that are slightly hydrophobic (PG(alkyl)), positively charged (PG(+)), or negatively charged (PG(−)). Subsequent inductive coupled plasma mass spectrometry 6 or 24 h after AuNPs administration reveals the biodistribution in silkworm hemolymph, midgut, epidermis, and excrements. Even after 24 h incubation, hemolymph contains the highest AuNPs concentrations, independent of surface functionalization indicating a prolonged circulation time and slow distribution into different silkworm organs and tissues. Positively charged PG(+)AuNPs show three times higher concentrations in the midgut and are excreted at the fastest rate when compared to other AuNPs. In the findings, a surface‐dependent biodistribution and elimination of AuNPs are indicated in silkworms, and the feasibility of using this inexpensive animal model for time‐ and cost‐effective, preliminary in vivo studies of NPs is confirmed.

Pediococcus pentosaceus ZZ61 enhances growth performance and pathogenic resistance of silkworm Bombyx mori by regulating gut microbiota and metabolites

Probiotics have attracted considerable attention in animal husbandry due to their positive effect on animal growth and health. This study aimed to screen candidate probiotic strain promoting the growth and health of silkworm and reveal the potential mechanisms. A novel probiotic Pediococcus pentosaceus strain (ZZ61) substantially promoted body weight gain, feed efficiency, and silk yield. These effects were likely mediated by changes in the intestinal digestive enzyme activity and nutrient provisioning (e.g., B vitamins) of the host, improving nutrient digestion and assimilation. Additionally, P. pentosaceus produced antimicrobial compounds and increased the antioxidant capacity to protect the host against pathogenic infection. Furthermore, P. pentosaceus affected the gut microbiome and altered the levels of gut metabolites (e.g., glycine and glycerophospholipids), which in turn promotes host nutrition and health. This study contributes to an improved understanding of the interactions between probiotic and host and promotes probiotic utilization in sericulture.