Pupae Research Articles

Wild Silkworm Cocoon Waste Conversion into Tough Regenerated Silk Fibers by Solution Spinning.

Wild silkworm silk fibers have garnered attention owing to their softness, natural color, lightweight, and excellent mechanical properties. Because most wild silkworm cocoons obtained are pierced or dirty after the eclosion process, it is difficult to reel the long filament from the pierced cocoons to use as textile materials. Therefore, damaged wild silkworm cocoons are typically removed during the industrial process. Artificial silk spinning has been developed to transform domesticated silkworm silk solutions into regenerated silk fibers. However, regenerated fibers derived from wild silkworm silk have not been reported. Here, we produced regenerated silk fibers using a dry-wet spinning method using a dope solution derived from wild silkworm silk cocoon wastes. These regenerated silk fibers have thick and uniform diameters, unlike native silk fibers, contributing to their usefulness for sterilization and handling in medical applications. Moreover, they exhibited the same level of mechanical strength as their native counterparts. The molecular orientation and crystallinity of the regenerated silk fibers were adjustable by the drawing process, enabling the realization of their various tensile properties. This study promotes the utilization of unused protein resources to produce mechanically stable and tough silk-based fibers.

Analysis of histomorphometric and proteome dynamics inside the silk gland lumen of Bombyx mori revealed the dynamic change of silk protein during the molt stage

Silkworms spin different silks at different growth stages for specific purposes. The silk spun before the end of each instar is stronger than that at the beginning of each instar and cocoon silk. However, the compositional changes in silk proteins during this process are unknown. Consequently, we performed histomorphological and proteomic analyses of the silk gland to characterize changes from the instar end to the next instar beginning. The silk glands were collected on day 3 of third- and fourth-instar larvae (III-3 and IV-3) and the beginning of fourth-instar larvae (IV-0). Proteomic analysis identified 2961 proteins from all silk glands. Silk proteins P25 and Ser5 were significantly more abundant in III-3 and IV-3 than in IV-0, and many cuticular proteins and protease inhibitors increased significantly in IV-0 compared with III-3 and IV-3. This shift may cause mechanical property differences between the instar end and beginning silk. Using section staining, qPCR, and western blotting, we found for the first time that silk proteins were degraded first and then resynthesized during the molting stage. Furthermore, we revealed that fibroinase mediated the changes of silk proteins during molting. Our results provide insights into the molecular mechanisms of silk proteins dynamic regulation during molting.

Silk Sericin Protein Materials: Characteristics and Applications in Food-Sector Industries.

There is growing concern about the use of plastic in packaging for food materials, as this results in increased plastic waste materials in the environment. To counter this, alternative sources of packaging materials that are natural and based on eco-friendly materials and proteins have been widely investigated for their potential application in food packaging and other industries of the food sector. Sericin, a silk protein that is usually discarded in large quantities by the sericulture and textile industries during the degumming process of manufacturing silk from silk cocoons, can be explored for its application in food packaging and in other food sectors as a functional food and component of food items. Hence, its repurposing can result in reduced economic costs and environmental waste. Sericin extracted from silk cocoon possesses several useful amino acids, such as aspartic acid, glycine, and serine. Likewise, sericin is strongly hydrophilic, a property that confers effective biological and biocompatible characteristics, including antibacterial, antioxidant, anticancer, and anti-tyrosinase properties. When used in combination with other biomaterials, sericin has proved to be effective in the manufacture of films or coating or packaging materials. In this review, the characteristics of sericin materials and their potential application in food-sector industries are discussed in detail.

Regulatory effect of sericin protein in inflammatory pathways; A comprehensive review.

Sericin protein is a type of protein derived from silk cocoons. Sericin hydrogen bonds cause adhesion to the silk cocoon. This substance contains a large amount of serine amino acids in its structure. At first, the medicinal properties of this substance were unknown, but today many properties have been discovered for this substance. The unique properties of this substance have made it widely used in the pharmaceutical and cosmetic industries. The applications of Sericin in pharmacy are as follows. Sericin is used to repair wounds by producing collagen. Other uses for the drug include anti-diabetic, anti-cholesterol, metabolic modulator, anti-tumor, heart protection, antioxidant, antibacterial, wound healing, cell proliferation, UV protection, freezing, and skin moisturizing. The physicochemical properties of Sericin have attracted the attention of pharmacists and their widespread use in the production of drugs and treatment of diseases. One of the critical and unique properties of Sericin is its anti-inflammatory property. In this article, this property of Sericin is discussed in detail, and according to the experiments performed by pharmacists, this substance has shown a significant effect in eliminating inflammation. This study aimed to evaluate the impact of Sericin protein in relieving inflammation.

Impact of temperature variations in worm containers and nutrition amount on silk glands and silk productivity

During the feeding of mulberry silkworms, when the temperature in the larvae fluctuates sharply and the amount of nutrients fed is below or above the norm, the metabolism and physiological processes in the body are disrupted. As a result, the silk cocoon water balance, respiration, digestion and absorption of nutrients are impaired, the activity of the silk glands is impaired, creating conditions for disease-causing microorganisms. In this case, the growth of silkworms by 4 times less when the worms are fed with 50% of the norm, reducing the amount of silk in the cocoon, as the larvae survive without healthy development and the productivity of the cocoons grown. This results in a 20.0% reduction in its average weight and a 23.3% decrease in the weight of the shell. At the same time, on farms where mulberry leaves are in short supply, the cocoon yield per box of worms is 15-30 kilograms, and the quality is 14% lower. This is due to the fact that the growth of mulberry silkworms as a result of the inability of the silk gland to accumulate enough silk fluid due to underdevelopment and the satiety of the mulberry leaf significantly affect the activity of the silk gland. Feeding silkworms with high-nutrient varieties of mulberry leaves increased silkworm size by 6.9-10.1%, viability by 2.5%, total cocoons, yield by 4.5%, yield by 8 kg. In particular, a sharp change in the air temperature of the worm relative to the norm (25-26 °C) weakens the activity of the silk gland due to disruption of the growth and development process of worms. Due to the reduction of the amount of silk liquid synthesized, the viability of worms is 6.5%, the weight of the cocoon is 61.5-64.4%, the weight of the silk shell is 73.7-74.5%, the yield is 8-10 kg, and the variety is 6-12%. decrease has been scientifically proven.

The Size Effect of Silver Nanoparticles on Reinforcing the Mechanical Properties of Regenerated Fibers.

Regenerated silk fibroin (RSF), made from discarded silk cocoons, can be processed into regenerated silk fibers by a simple, inexpensive, and environmentally friendly wet-spinning process. However, the breaking strength and toughness of most RSF fibers are lower than those of natural silk. In this study, Ag nanoparticles (NPs) of different sizes were introduced into RSF to form RSF/AgNPs hybrid fibers by wet spinning. The effects of AgNPs of different sizes on the mechanical properties and structure of the hybrid fibers were investigated. The results demonstrated that the mechanical properties of hybrid fibers were significantly improved, especially the breaking strain, after the addition of four different sizes of AgNPs. With the reduction in AgNPs size (2-60 nm), the breaking strength and breaking strain of hybrid fibers tended to increase. The results showed that the hybrid fibers containing 2 nm AgNPs were remarkable, with excellent mechanical properties and toughness, and the breaking strain reached 138.27%, which was far greater than blank RSF fibers (15.02%) and even natural silk (about 21%). The S-FTIR and WAXD showed that, compared with the larger AgNPs, the smaller AgNPs contributed more to the formation of silk fibroin β-sheet and crystallinity, and reduced the β-crystallite size. This study is helpful to understand the relationship between the size of nanoparticles and the mechanical properties of hybrid fibers.

Biodegradable radiative cooling membrane based on electrospun silk fibroin fiber

AbstractBiodegradable radiative cooling materials can achieve both zero‐energy cooling and environmental friendliness. Natural silk cocoon exhibits both high solar reflectivity and mid‐infrared emissivity owing to its unique structure and composition, while it possesses excellent biodegradability. Herein, we restructure the natural silk by electrospinning to obtain scalable and biodegradable silk fibroin (SF) fiber membranes with enhanced optical properties. Specially, nano‐sized fibers exhibit better optical properties than micrometer‐sized ones. The fabricated SF nanofiber membrane can achieve ultra‐high average solar reflectance and infrared emittance of 96% and ~97%, respectively. Such outstanding optical properties enables the fiber membrane to yield an average sub‐ambient cooling temperature of ~6°C in the outdoor environment even under a peak solar intensity of ~800 W m−2. Overall, the resulted SF fiber membranes promise a wide range of applications such as building energy efficiency, cold‐chain transportation, in‐vehicle temperature control, outdoor precision instrument protection and outdoor personal thermal management.

The prevalence of Galleria mellonella and Achoria grisella in Apis mellifera Colonies in the Ludhiana District

Wax moths are a worldwide pest of honeybee colonies. They belong to the Galleriinae subfamily of the Pyralidae family in the order Lepidoptera. The Greater wax moth (Achroia grisella) and the Lesser wax moth (Achroia grisella) are the two species of wax moths (Galleria mellonella). The Greater Wax Moth is the most disastrous in apiaries causing annual financial losses. Furthermore, larval feeding deteriorates wax combs and destroys hive frames and wooden elements. Wax moths feed on hive products such as wax, cast-off honey bee pupal skin, larval bee remnants, pollen, encapsulated honey bee excrement found on brood cell walls, honey bee cocoon silk and honey bee cocoon silk. They produce massive amounts of the web by entering the comb's midrib. Almost all Asian honeybee, hives are infested with wax moths. In 2021-22, GWM and LWM activities were carried out in storage at Big Bee Farm, Atwal Bee Farm and Tiwana Bee Farm. Galleria mellonella and Achroia grisella seasonally began in March, peaked in July and August and then began to decline. The highest G. mellonella and A. grisella population densities were seen during the months with mean temperatures of 32–34 degrees Celsius and relative humidity of 70–80% (50–55 RH per cent). During the winter, the study found the fewest wax moth larvae, pupae and adults in all bee storage farms.

Automated Prototype for Bombyx mori Cocoon Sorting Attempts to Improve Silk Quality and Production Efficiency through Multi-Step Approach and Machine Learning Algorithms.

Cocoon sorting is one of the most labor-demanding activities required both at the end of the agricultural production and before the industrial reeling process to obtain an excellent silk quality. In view of the possible relaunch of European sericulture, the automatization of this production step is mandatory both to reduce silk costs and to standardize fiber quality. The described research starts from this criticality in silk production (the manual labor required to divide cocoons into different quality classes) to identify amelioration solutions. To this aim, the automation of this activity was proposed, and a first prototype was designed and built. This machinery is based on the use of three cameras and imaging algorithms identifying the shape and size of the cocoons and outside stains, a custom-made light sensor and an AI model to discard dead cocoons. The current efficiency of the machine is about 80 cocoons per minute. In general, the amelioration obtained through this research involves both the application of traditional sensors/techniques to an unusual product and the design of a dedicated sensor for the identification of dead/alive pupae inside the silk cocoons. A general picture of the overall efficiency of the new cocoon-sorting prototype is also outlined.

How al-Andalus wrapped itself in a silk cocoon: the ṭirāz between Umayyad economic policy and Mediterranean trade

Sericulture and the state supervision of textile production was a longstanding tradition in the Middle East during the pre-Islamic period. However, neither were known in the Iberian Peninsula. With the rise of Islam, the luxury fabrics produced by the state institution of ṭirāz became a prominent symbol of sovereignty, encouraging the Umayyads of al-Andalus (138 h./756–422 h./1031) to create their own ṭirāz workshop, which specialized in silk fabrics, after sericulture was introduced in Iberia under their rule. Little was known about this productive process, as existing studies have tended to focus exclusively on one of the multiple types of evidence available: Arabic, Latin and Hebrew textual sources; chemical, technical and decorative analysis of preserved textiles; and others. This paper uses all the evidence available to undertake a comprehensive study of the operation of the Umayyad ṭirāz workshop in al-Andalus. Beginning with the tributary and administrative factors that surrounded the institution, the process by which demand for silk in the Mediterranean markets gave private merchants the instruments to control the Andalusi textile sector is analysed. By the fifth h./eleventh century, al-Andalus had become the main supplier of silk goods in the Mediterranean.

Synthesis of Biogenic Gold Nanoparticles by Using Sericin Protein from Bombyx mori Silk Cocoon and Investigation of Its Wound Healing, Antioxidant, and Antibacterial Potentials.

A number of biological wastes and factory waste materials have been tested recently for the eco-friendly biosynthesis of nanoparticles. Sericin protein (SSP) is usually removed from the silk cocoon during the degumming process in the process of making the silk, and this sericin protein is normally thrown away by the sericulture industries as waste materials. It is found that this sericin protein possesses a number of biological properties. Considering this, in the present study, an effort has been made to biosynthesize gold nanoparticles (SSP-AuNPs) using the waste sericin solution as the reducing and capping agent and investigate its biopotential in terms of its wound healing, antioxidant and antibacterial activities. The synthesis of SSP-AuNPs was perceived by the visual color change and confirmed by UV-Vis spectroscopy with absorption maxima at 522 nm. Further characterization of SSP-AuNPs was done by TEM, EDS, XRD, FTIR, DLS, zeta potential, TGA, AFM, etc. The size of SSP-AuNPs was found out to be 54.82 nm as per the particle size analyzer and the zeta potential is -19.8 mV. The SSP-AuNPs displayed promising wound healing potential of 70.96 and 69.76% wound closure rate at 5 and 10 µg/mL respectively as compared to 74.91% by the Centella asiatica taken as a positive control. It also exhibited promising antioxidant potential in terms of the DPPH, ABTS free radical scavenging, reducing power potential, and total antioxidant capacity. Besides, the SSP-AuNPs also displayed significant antibacterial activities against the tested pathogenic bacterial with the diameter of inhibition zones ranging between 12.10 and 14.96 mm as compared to the positive control cephalexin that displayed inhibition zones ranging between 12.08 and 13.24 mm. Taken together, SSP-AuNPs could serve as an interesting candidate for food, cosmetics, and biomedical fields in the applications of wound healing, cosmetics, antibacterial bandages, and ointments, etc.

Effects of Amino Acids on Food Intake, Silk Gland and Protein Content of Silkworm, Bombyx mori L

Studies were undertaken to assess the effects of amino acids on the food intake, silk gland, and protein content of silkworm, Bombyx mori L. Three amino acids, namely Glycine, Alanine and Serine at various concentrations viz., 10, 20, 50, 100 and 200 ppm were used for the investigations. The silkworm larvae were supplemented with amino acids, once daily in the morning from first day of fifth instar to spinning. Experimental results showed that irrespective of the concentrations studied, the amino acids had positive influence on the food intake, silk gland, and protein content of silkworms. Though all the treatments were found to significantly increase different parameters namely co-efficient of food utilization, weight and length of silk gland, protein content in silk gland, haemolymph and cocoon the enhancement was highest at concentration of 10 ppm, 100 ppm and 100 ppm, respectively in Glycine, Alanine and Serine

Research primary processing of live of silk cocoons in a solar installation

This article presents the results of research to determine the main technical and economic indicators of a new installation we have created for marinating cocoons with the help of solar radiation energy. The possibility of marinating cocoons both on sunny and cloudy days has been proven through direct and indirect use of the energy of solar radiation. The performance of the installation, the temperature inside the drying chamber and the time for complete marinating of cocoons were determined. On the basis of the data obtained, it can be said that the installation provides complete of marinating cocoons and the use of this installation contributes to 100 percent savings in energy resources spent for freezing cocoons.

Ultrahigh surface area of single-atom iron nanosheets assists in the efficient utilization of reactive oxygen species in the peroxymonosulfate activation process for pollutant removal

SAFe/CNS synthesized via a cocoon silk chemistry strategy exhibits ultrahigh specific surface area, which brings out a large adsorption capacity for organic pollutants, thereby effectively utilizing the vicinal as-generated active species.

High-performance artificially reeled silkworm silk via a multi-task and high-efficiency centrifugal reeling technique and its application in soft actuators.

Silkworm silks show increasing potential in applications of bioengineering, sensors, optics, electronics, and actuators. However, their inherent irregular morphologies, structures, and properties greatly hinder the translation of these technologies to commercial applications. Herein, we report a facile and comprehensive strategy to fabricate high-performance silk materials by spinning silkworms artificially via a multi-task and high-efficiency centrifugal reeling technique. With this strategy, centrifugally reeled silks (CRSs) with long-uniform morphologies, excellent strength (844.83 ± 319.48 MPa), high toughness (121.07 ± 35.31 MJ m-3), and outstanding Young's modulus (27.72 ± 12.61 GPa) are developed. Remarkably, the maximum strength (1.45 GPa) of CRS is 3 times that of cocoon silk and even comparable to spider silk. Moreover, the centrifugal reeling technique realizes the one-step preparation of centrifugally reeled silk yarn (CRSY) from spinning silkworm, and the CRSYs show higher strength (877.38 ± 377.23 MPa) and superior torsional recovery performances. Furthermore, these CRSY-based soft pneumatic actuators (SPAs) exhibit light weight, high-loading capability, easy programmability in strength and motions, and fast responses, and therefore outperform currently reported elastomer-based SPAs, showing promising applications in flexible sensors, artificial muscles, and soft robotics. This work also provides a new guide for producing high-performance silks from silk-secreting insects and arthropods.

Biocompatible and bioactive PVA/Sericin/Chitosan nanofibrous wound dressing matrix

This work focuses on preparation of electrospun matrix for wound dressing application by utilizing sericin, chitosan and silver nanoparticles in PVA nanofibers. Sericin (SS) is extracted from silk cocoon (Bombyx Mori) by alkali degumming method. The extracted sericin is characterised by UV-visible Spectroscopy and FT-IR. Then, individual stock solutions of 2% (w/v) Chitosan (CH) in acetic acid, 10% (w/v) of PVA in deionised water were prepared. To enhance the antimicrobial property to the wound dressing, silver nanoparticles (Ag NP) was prepared using Cynodan dactylon (Bermuda grass) leaves extract and characterised using UV-visible Spectroscopy. The prepared Ag NP was incorporated in the nanofibers at constant proportion. Furthermore, three blended PVA/SS/CH solutions were prepared in the following ratios 8:1:1, 5:2.5:2.5, and 2:4:4 and electrospun to create nanofibrous dressing material. The structural and physical characteristics of the prepared nanofibrous dressing material were studied using SEM and Universal Testing Machine. Based upon mechanical strength and SEM analysis PVA/SS/CH in the ratio 8:1:1 was chosen for In-vitro studies. From the studies it concludes that the prepared PVA/SS/CH electrospun nanofiber will be a promising material for wound dressing.

Comparative Silk Transcriptomics Illuminates Distinctive Impact of Artificial Selection in Silkworm Modern Breeding.

Early domestication and the following improvement are two important processes in the cocoon silk evolution of silkworms. In contrast to early domestication, understanding of the improvement process is still fuzzy. By systematically comparing the larval silk gland transcriptomes of the wild, early domestic, and improved silkworms, we highlighted a novel landscape of transcriptome in the silk glands of improved ones. We first clarified that silk cocoon protein genes were up-regulated in modern breeding but not in early domestication. Furthermore, we found that differentially expressed genes (DEGs) between improved and early domestic silkworms (2711), as well as between improved and wild silkworms (2264), were obviously more than those between the early domestic and wild silkworms (158), with 1671 DEGs specific in the improved silkworm (IS-DEGs). Hierarchical clustering of all the DEGs consistently indicated that improved silkworms were significantly diverged from the early domestic and wild silkworms, suggesting that modern breeding might cause prompt and drastic dynamic changes of gene expression in the silk gland. We further paid attention to these 1671 IS-DEGs and were surprised to find that down-regulated genes were enriched in basic organonitrogen compound biosynthesis, RNA biosynthesis, and ribosome biogenesis processes, which are generally universally expressed, whereas those up-regulated genes were enriched in organonitrogen compound catabolic processes and functions involving in the dynamic regulation of protein post-translation of modification. We finally highlighted one candidate improvement gene among these up-regulated IS-DEGs, i.e., GDAP2, which may play roles in silk behavior and the overall robustness of the improved silkworm. The findings strongly suggest that modern breeding may facilitate effective control of the basic consumption of nitrogen and a stronger switch of nitrogen resources from other tissues to the silk glands, for an efficient supply for silk production, and implies the importance of brain behavior and robustness in silk yield improvement of modern breeding.

Effect of Ethanol Post-Treatments over Sericin Scaffolds for Tissue Engineering Applications

Protein-based biomaterials are excellent candidates for biomedical applications since they have similar properties to the extracellular matrix. Recently, the use of sericin (SS), a protein present in the silk cocoon, can be used as biomaterial. To improve their properties, SS biomaterials must be subject to treatments after their manufacturing. Ethanol post-treatments by immersion and solvent vapor, are used for increasing their crystallinity, mechanical and water stability. In this work, the effect of ethanol post-treatment on the properties of SS scaffolds elaborated by the lyophilization technique was evaluated. Four post-treatments were carried out on the samples: immersed in absolute ethanol for 5 min (SS/EtOH 5 min) and for 1 h (SS/EtOH 1 h); and exposition in a saturated ethanol vapor environment for 1 h (SS/VapEtOH 1 h) and for 24 h (SS/VapEtOH 24 h). The scaffolds were characterized by X-ray diffraction (XRD) and Fourier‑transform infrared spectroscopy (ATR-FTIR), scanning electron microscopy (SEM), water absorption, degradation in a phosphate-buffered saline solution, sericin release from the scaffolds, and the cytotoxicity test. The ATR-FTIR results showed an increment in the relative content of β-sheet structures and an increment in the crystallinity. SEM images revealed that the post-treatment process induces changes in treated materials to present morphological changes. The treatment materials were more water-stable. The excipients of the SS scaffolds evaluated in human epithelial fibroblasts do not generate an acute cytotoxic effect. The results suggest that ethanol post-treatments induce conformational transitions and morphological changes, which should be considered for selecting the post-treatment conditions according to developing materials for wound regeneration.

Optimal Date of Mulberry Pruning and Silkworm Rearing for Improvement of Quality and Yield Potential of Mulberry Foliage and Silk Cocoons in Lower-Gangetic Region

Optimal Date of Mulberry Pruning and Silkworm Rearing for Improvement of Quality and Yield Potential of Mulberry Foliage and Silk Cocoons in Lower-Gangetic Region

Integrated Evaluation of Dual-Functional DPP-IV and ACE Inhibitory Effects of Peptides Derived from Sericin Hydrolysis and Their Stabilities during In Vitro-Simulated Gastrointestinal and Plasmin Digestions.

Sericin, a byproduct of the silk industry, is an underutilized protein derived from the yellow silk cocoon. This research aimed to produce and characterize the bioactive peptides from sericin using various enzymatic hydrolysis methods. Alcalase, papain, neutrase, and protease were tested under their respective digestion conditions. Among the enzymes tested, neutrase-catalyzed sericin into specific peptides with the strongest dipeptidyl peptidase IV (DPP-IV) and angiotensin-converting enzyme (ACE) inhibitory properties. The peptides were subjected to a simulated in vitro gastrointestinal (GI) digestion in order to determine their stability. The GI peptides that were produced by neutrase hydrolysis continued to have the highest DPP-IV and ACE inhibitory activities. The neutrase -digested peptides were then fractionated via ultrafiltration; the peptide fraction with a molecular weight <3 kDa (UF3) inhibited DPP-IV and ACE activities. After being subjected to in vitro blood plasma hydrolysis, the UF3 was slightly degraded but retained its bioactivity. As a result of these findings, sericin peptides can be utilized as novel dietary ingredients that may alleviate some metabolic syndromes via the dual inhibitory properties of DPP-IV and ACE.