Wild Silk Research Articles

Cocoon quantitative traits and grainage behaviour in Jhanji crop of wild Modal ecorace of Tasar silkworm in Similipal

The present study describes the quantitative cocoon traits and egg production behaviour during Jhanji crop in three different locations. The wild cocoons were kept in pagoda during March and quantitative cocoon traits were recorded. The results indicated wide range of variation for all traits except shell ratio. The pupal weight and cocoon volume values were highest at Kendujauni than Sarat and Astabeda. In case of female, cocoon weight, pupal weight and cocoon volume values were significantly highest at Kendujauni followed by Sarat and lowest at Astabeda. Shell weight and cocoon length values were significantly highest for Kendujuani where as Sarat and Astabeda were at par. The grainage parameters were recorded from April to June. A total of 2111, 1803 and 1876 female moths emerged in Kendujuani, Sarat and Astabeda, respectively. The total number of couplings were 1405 (66.56%), 1158 (64.23%) and 898 (47.87%) respectively. From this it is evident that availability of wild males in the forest of Astabeda area of Similipal is significantly less. The pattern of emergence at one week interval also varied, early mass emergence followed by one more peak in June was recorded in Astabeda and Kendujuani. But in Sarat, almost uniform emergence with one peak in June was recorded. Thus, more attention is warranted for the proliferation of wild silk moth populations in Astabeda and eastern part of Similipal.

Collagen-tussah silk fibroin hybrid scaffolds loaded with bone mesenchymal stem cells promote skin wound repair in rats.

This study demonstrates the efficacy of collagen/tussah silk fibroin (Col/TSF) hybrid scaffolds loaded with bone mesenchymal stem cells (BMSCs) in skin repair. Collagen (Col) and tussah silk fibroin (TSF) were extracted from bovine tendons and tussah cocoons, respectively. Col/TSF scaffolds were obtained using a freeze-drying method and were characterised using fourier transform infrared spectroscopy, scanning electron microscopy, porosity, water retention, thermal stability, and biocompatibility. The results revealed that addition of TSF to scaffolds could enhance their moisturising ability and cell infiltration. The antibacterial properties of Col/TSF scaffolds loaded with antibiotics were also excellent. BMSCs cultured in contact with developed Col/TSF scaffolds showed increased cell adhesion, viability, and differentiation. An in vivo study on rats showed that the Col/TSF scaffold seeded with BMSCs was more conducive to wound healing compared to the Col/TSF scaffold alone. The present study suggests that Col/TSF scaffold seeded with BMSCs could be a promising candidate for skin tissue engineering, due to its excellent skin affinity, good air and water permeability, and improved wound healing potential.

A Comparison of Color Fastness Properties of Mulberry Silk and Tussah Silk Fabrics in Blends with Cellulosic Fibers

ABSTRACT Although it has been used for centuries; silk’s appearance, touch, and other high-quality properties maintain the popularity of the fiber. However, there are different types of silkworms, so different types of silk fibers are available. Other than Mulberry silk there are some others: eri, muga, tasar and tussah, which are generally deemed “wild silk”. In this study, color fastness properties of one of these wild silk fibers: tussah was investigated in comparison with mulberry silk fiber. For comparison, mulberry and tussah silk fibers were blended with cotton, viscose rayon, and modal fibers and spun using open-end rotor spinning system. After yarn productions; single jersey fabrics were knitted, pretreated and dyed. Color fastness tests were made to evaluate the performances. Results indicate that both types of silk fibers are appropriate for spinning and knitting processes and the fastness results revealed that mulberry fibers resulted with better color fastness properties in comparison with tussah silk fibers

Formic Acid Regenerated Mori, Tussah, Eri, Thai, and Muga Silk Materials: Mechanism of Self-Assembly.

Flexible and water-insoluble regenerated silk materials have caught considerable interest due to their mechanical properties and numerous potential applications in medical fields. In this study, regenerated Mori (China), Thai, Eri, Muga, and Tussah silk films were prepared by a formic acid-calcium chloride (FA) method, and their structures, morphologies, and other physical properties were comparatively studied through Fourier transform infrared spectroscopy (FTIR), wide-angle X-ray scattering (WAXS), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and thermogravimetric analysis (TGA). FTIR results demonstrated that the secondary structures of those five types of silk films are different from those of their respective natural silk fibers, whose structures are dominated by stacked rigid intermolecular β-sheet crystals. Instead, intramolecular β-sheet structures were found to dominate these silk films made by FA method, as confirmed by WAXS. We propose that silk I-like structures with intramolecular β-sheets lead to water insolubility and mechanical flexibility. This comparative study offers a new pathway to understanding the tunable properties of silk-based biomaterials.

Isolation and Molecular Identification of Microsporidian Pathogen Causing Nosemosis in Muga Silkworm, Antheraea assamensis Helfer (Lepidoptera: Saturniidae).

Microsporidia are intracellular fungal parasites and they are the most common pathogens for sericulture. Microsporidian sp. can cause pebrine, a dreadful disease and lead to destructive disorder in Muga silkworm, Antheraea assamensis Helfer by vertical and horizontal transmission. This disease is the key factor obstructing the developmental progress of Muga culture in India. Nevertheless, molecular identification and characterization of pathogen associated with pebrine disease in A. assamensis is not yet established. Insect bioassay studies revealed that microsporidian infection in Muga silkworm, A. assamensis Helfer significantly reduced (P < 0.005) cocoon weight, pupal weight, shell weight and silk ratios. A new set of PCR primers suitable for amplification of small subunit ribosomal RNA (SSU-rRNA) of microsporidia infecting A. assamensis have been designed. The amplicon was cloned, sequenced and analysed. Microsporidia pathogen of wild silk moth A. assamensis has been identified at genus level as Nosema sp. AA1. Phylogeny of Nosema sp. AA1 was constructed on the basis of SSU-rRNA sequence and it has a close evolutionary relationship with microsporidian pathogens of other wild silkmoths. The arrangement and organization of the rRNA genes inferred that Nosema sp. AA1 belongs to true Nosema group and not to members of the Nosema/Vairimorpha group.

The application of FTIR microspectroscopy in a non-invasive and non-destructive way to the study and conservation of mineralised excavated textiles

The potential of Fourier Transform Infrared (FTIR) microspectroscopy, to inform the study and conservation of mineralised excavated textiles is discussed, highlighted by two case studies of 5th c. BCE finds. In both cases the textiles were funerary from pyre burials, used to wrap the remains of the incinerated bones of the deceased, and placed inside copper alloy urns, to be buried. FTIR spectra of the textile fibres were acquired by an FTIR microscope in reflectance mode. In regard to the two case studies, this was a non-invasive and non-destructive method, since it did not involve removal of material for sampling, as both finds were in a fragmentary condition, it did not apply any pressure, nor did it require pressing of the minute fragments used as samples. Past fibre analyses in case study A reported cultivated and wild silk, which had been used as evidence of the presence of silk in Classical Greece, while more recent studies, controversially pointed to either cellulosic or wool fibres. The unlimited application of FTIR microspectroscopy in reflectance mode due to its non-invasive/destructive nature, enhanced fibre identification but most importantly led to further analyses of specific fragments that revealed the find was suffering from active biodeterioration, subsequently treated. Case study B, where the textiles had been preserved folded, was a particularly unique find from its period, since one of the textiles present was bearing evidence of embroidery. Similarly, the extended application of FTIR microspectroscopy indicated good preservation of the organic matter within the fibres, informing thus the conservation decision-making process, which involved partial unfolding of the textiles, an action that revealed an additional decoration pattern, and minute fragments of the embroidery thread preserved.

Structure and Properties of Bombyx Mandarina Silk Fiber and Hybrid Silk Fiber

ABSTRACT Bombyx mandarina silk fibers, as a precious resource of wild silk fibers, have some different characteristics to Bombyx mori silk fibers. To make a better use of this precious green material in various fields, it is necessary to investigate the characteristics of the fibers. In this research, the structure and properties of Bombyx mori silk fiber, Hybrid silk fiber, and Bombyx mandarina silk fiber are studied and analyzed. In terms of secondary structure, β-sheet structures are dominant in all three fibers while random coil and α-helix structures account for smaller portions of the fibers. Bombyx mandarina silk fiber exhibits a characteristic of amino acid distribution where the content of glycine is higher than that of alanine. The further analysis indicates the breaking strength of B. mandarina silk fibers is superior to that of B. mori silk fiber although Bombyx mandarina silk fiber is finer than Bombyx mori silk fiber. Our investigations provide a significant guide in the development and utilization of these precious silk resources, and Bombyx mandarina and Hybrid silk fibers show good potential for application in the same fields as Bombyx mori silk fibers.

Water-Rinsed Nonmulberry Silk Film for Potential Tissue Engineering Applications

The possibility of using nonmulberry silk fibroin as a biomaterial is a subject of broad interest due to its inherent RGD sequence. However, the extraction of silk fibroin from cocoons and silk glands remains a formidable task. In this work, we report a facile method to dissolve tussah silk using CaCl2–formic acid and a water-rinsing process for regeneration of tussah silk fibroin (TSF) film. The new technique is important and valuable because it can directly extract silk fibroin from cocoons and is advantageous over other previous reported methods using LiSCN and Ca(NO3)2. The morphology, chemical structure, and mechanical properties of regenerated film rinsed with water, ethanol, and methanol are characterized by scanning electron microscopy, Fourier transform infrared, and X-ray diffraction techniques in combination with mechanical testing. The results reveal that the regenerated TSF films possess a smooth surface and nanostructural cross section and exhibit predominantly β-sheet crystal structure and ...

Biological effects different diameters of Tussah silk fibroin nanofibers on olfactory ensheathing cells.

Transplantation of olfactory ensheathing cells (OECs) has potential for treating spinal cord and brain injury. However, they are void of an extracellular matrix to support cell growth and migration. Engineering of tissue to mimic the extracellular matrix is a potential solution for neural repair. Tussah silk fibroin (TSF) has good biocompatibility and an Arg-Gly-Asp tripeptide sequence. A small number of studies have assessed the effect of the diameter of TSF nanofibers on cell adhesion, growth and migration. In the present study, TSF nanofibers with a diameter of 400 and 1,200 nm were prepared using electrospinning technology; these were then used as scaffolds for OECs. The structure and morphology of the TSF nanofibers were characterized by scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy. An inverted-phase contrast microscope and SEM were used to observe the morphology of OECs on the TSF nanofibers. The effect on the adhesion of the cells was observed following crystal violet staining. The phenotype of the cells and the maximum axon length on the scaffolds were evaluated by immunostaining for nerve growth factor receptor p75. Cell proliferation and viability were assessed by an MTT assay and a Live/Dead reagent kit. The migration efficiency of OECs was observed using live-cell microscopy. The results indicated that a 400-nm TSF fiber scaffold was more conducive to OEC adhesion, growth and migration compared with a 1,200-nm TSF scaffold. The phenotype of the OECs was normal, and no difference in OEC phenotype was observe when comparing those on TSF nanofibers to those on PLL. The present study may provide guidance regarding the preparation of tissue-engineered materials for neural repair.

The Status of Sericulture in Ghana

Sericulture involves the rearing of silk-producing insects in captivity or collecting their silk cocoons in the field for production offabrics. The majority of the world’s silk is mulberry obtained from the domesticated silkworm, Bombyx mori L. (Lepidoptera:Bombycidae). Sericulture was formally introduced into Ghana in 1992 leading to the establishment of the Silk FarmersAssociation, and later a silk factory in 2002 with support from the FAO. This boost led to an increase in raw cocoon production,but is now dwindling due to numerous challenges facing the silk industry. A survey was carried out in the Eastern, BrongAhafo and Northern Regions of Ghana to establish the current status of sericulture. The survey revealed that farmers aremostly engaged in mulberry sericulture with wild silk being minimal, restricted to the rearing of the Eri silkworm, Philosamiaricini (Donovan) (Lepidoptera: Saturniidae) on castor oil and cassava leaves. Another important wild silkmoth, Gonometa sp.(Lepidoptera: Lasiocampidae) was found on Acacia sp. in northern Ghana. Brong-Ahafo region had the highest number ofsilk farmers. Farmers’ participation in sericulture has decreased over the years as a result of many setbacks. The prospectsand challenges confronting the sericulture industry in Ghana are discussed.

The protective ability of Camellia meal extract on the silk protein

With the enhancement of living standards, people pay more and more attention to the health. The edible oil become more and more popular, but also produced a large amount of Camellia meal which can not fully put into utilization. In this study, the extracting liquid of Camellia meal was used on the process of silk degumming. Firstly, tussah silk was treated by degumming in the Na2CO3 solution, and the preliminary condition of tussah silk degumming was obtained by orthogonal experiment: the concentration Na2CO3 was 0.1%, the degumming time was 1 hour, and the ratio of silk/water was 40:1. Then the extract of Camellia meal (GCJSY) was added before the bleaching process of tussah silk to investigate the protective ability of GCJSY on the silk protein basry on the residual ratio of the silk. While the concentration of GYJSY was 0.08%, the residual ratio of silk after degumming in the Na2CO3 solution and bleaching in the 2% H2O2 solution was 87.2%.

Structure and properties of Camphor silk

Wild non-mulberry silk has long been mainly used as a textile fiber and as biomedical sutures for decades. In this study, we reported a unique wild silk variety, the Camphor silk. Compared with the Bombyx mori (B. mori) silk and Antheraea pernyi (A. pernyi) silk cocoons, the Camphor silkworm cocoon is smaller and has a thinner cocoon wall. Similar to the A. pernyi cocoon, the Camphor cocoon also has a large amount of crystals covering its outer layers. The breaking strength and tenacity of the Camphor silk with and without degumming were significantly higher than that of A. pernyi and B. mori silks. Moreover, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and thermo gravimetric (TG) analyses were employed to provide an insight into the superior mechanical properties of the Camphor silk. The results showed that the Camphor silk has a high degree of crystallinity and high decomposition temperature (329 °C), which contribute to its outstanding mechanical properties. This study provides a new alternative protein material for composites and biomedical devices.

Incorporating biotic interactions in the distribution models of African wild silk moths (Gonometa species, Lasiocampidae) using different representations of modelled host tree distributions

AbstractBiotic interactions influence species niches and may thus shape distributions. Nevertheless, species distribution modelling has traditionally relied exclusively on environmental factors to predict species distributions, while biotic interactions have only seldom been incorporated into models. This study tested the ability of incorporating biotic interactions, in the form of host plant distributions, to increase model performance for two host‐dependent lepidopterans of economic interest, namely the African silk moth species, Gonometa postica and Gonometa rufobrunnea (Lasiocampidae). Both species are dependent on a small number of host tree species for the completion of their life cycle. We thus expected the host plant distribution to be an important predictor of Gonometa distributions. Model performance of a species distribution model trained only on abiotic predictors was compared to four species distribution models that additionally incorporated biotic interactions in the form of four different representations of host plant distributions as predictors. We found that incorporating the moth–host plant interactions improved G. rufobrunnea model performance for all representations of host plant distribution, while for G. postica model performance only improved for one representation of host plant distribution. The best performing representation of host plant distribution differed for the two Gonometa species. While these results suggest that incorporating biotic interactions into species distribution models can improve model performance, there is inconsistency in which representation of the host tree distribution best improves predictions. Therefore, the ability of biotic interactions to improve species distribution models may be context‐specific, even for species which have obligatory interactions with other organisms.

Biomineralized poly (l-lactic-co-glycolic acid)-tussah silk fibroin nanofiber fabric with hierarchical architecture as a scaffold for bone tissue engineering

In bone tissue engineering, the fabrication of a scaffold with a hierarchical architecture, excellent mechanical properties, and good biocompatibility remains a challenge. Here, a solution of polylactic acid (PLA) and Tussah silk fibroin (TSF) was electrospun into nanofiber yarns and woven into multilayer fabrics. Then, composite scaffolds were obtained by mineralization in simulated body fluid (SBF) using the multilayer fabrics as a template. The structure and related properties of the composite scaffolds were characterized using different techniques. PLA/TSF (mass ratio, 9:1) nanofiber yarns with uniform diameters of 72±9μm were obtained by conjugated electrospinning; the presence of 10wt% TSF accelerated the nucleation and growth of hydroxyapatite on the surface of the composite scaffolds in SBF. Furthermore, the compressive mechanical properties of the PLA/TSF multilayer nanofiber fabrics were improved after mineralization; the compressive modulus and stress of the mineralized composite scaffolds were 32.8 and 3.0 times higher than that of the composite scaffolds without mineralization, respectively. Interestingly, these values were higher than those of scaffolds containing random nanofibers. Biological assay results showed that the mineralization and multilayer fabric structure of the composite nanofiber scaffolds significantly increased cell adhesion and proliferation and enhanced the mesenchymal stem cell differentiation toward osteoblasts. Our results indicated that the mineralized nanofiber scaffolds with multilayer fabrics possessed excellent cytocompatibility and good osteogenic activity, making them versatile biocompatible scaffolds for bone tissue engineering.

Genome sequence of the Japanese oak silk moth, Antheraea yamamai: the first draft genome in the family Saturniidae.

Background Antheraea yamamai, also known as the Japanese oak silk moth, is a wild species of silk moth. Silk produced by A. yamamai, referred to as tensan silk, shows different characteristics such as thickness, compressive elasticity, and chemical resistance compared with common silk produced from the domesticated silkworm, Bombyx mori. Its unique characteristics have led to its use in many research fields including biotechnology and medical science, and the scientific as well as economic importance of the wild silk moth continues to gradually increase. However, no genomic information for the wild silk moth, including A. yamamai, is currently available.FindingsIn order to construct the A. yamamai genome, a total of 147G base pairs using Illumina and Pacbio sequencing platforms were generated, providing 210-fold coverage based on the 700-Mb estimated genome size of A. yamamai. The assembled genome of A. yamamai was 656 Mb (>2 kb) with 3675 scaffolds, and the N50 length of assembly was 739 Kb with a 34.07% GC ratio. Identified repeat elements covered 37.33% of the total genome, and the completeness of the constructed genome assembly was estimated to be 96.7% by Benchmarking Universal Single-Copy Orthologs v2 analysis. A total of 15 481 genes were identified using Evidence Modeler based on the gene prediction results obtained from 3 different methods (ab initio, RNA-seq-based, known-gene-based) and manual curation.ConclusionsHere we present the genome sequence of A. yamamai, the first genome sequence of the wild silk moth. These results provide valuable genomic information, which will help enrich our understanding of the molecular mechanisms relating to not only specific phenotypes such as wild silk itself but also the genomic evolution of Saturniidae.

Secondary Metabolite Profiling of Four Host Plants Leaves of Wild Silk Moth Attacus atlas L.

Secondary metabolites may affect insect herbivores’ host plant preferences. Attacus atlas L. larvae are known have a wider variety of host plants compared with other members of the Attacus genus. This research compared the metabolic profiles of four A. atlas host plants: keben (Barringtonia asiatica (L.) Kurz), dadap (Erythrina lithosperma Miq.), gempol (Nauclea orientalis L.), and soursop (Annona muricata L.). Leaves were collected from Sawit Sari Research Station, Yogyakarta. Terpenoid was extracted by macerating the leaves in ethyl acetate and subjecting them to GC-MS analysis, while alkaloid, tannin, and flavonoid were extracted through percolation. Total alkaloids, tannins, and flavonoids were measured using spectrophotometric analysis. Multivariate data analysis using PAST ver. 3.0 was performed on the GC-MS data. Based on the PCA scatter plot of the GC-MS data, keben leaves were clustered separately from the other three leaves by PC1. Dadap and gempol leaves were clustered together due to the phytol content while caryophyllene was detected only in soursop leaves. Neophytadiene was detected in all of the leaves, suggesting that this terpenoid may serve as a signal to locate the host plants. Keben leaves contained the lowest alkaloids and highest tannins and flavonoids compared with the other leaves. These secondary metabolites may determine the host plant suitability for culturing the A. atlas.

Physico-chemical characterization of Antheraea mylitta silk mats for wound healing applications

In the field of plastic reconstructive surgery, development of new innovative matrices for skin repair is in demand. The ideal biomaterial should promote attachment, proliferation and growth of cells. Additionally, it should degrade in an appropriate time period without releasing harmful substances, not exerting a pathological immune response. The materials used should display optimized mechanical properties to sustain cell growth and limit scaffold contraction. Wound healing is a biological process directed towards restoration of tissue that has suffered an injury. An important phase of wound healing is the generation of a basal epithelium wholly replacing the epidermis of the wound. Wild silk from Antheraea mylitta meets these demands to a large extent. To evaluate the effects of the treatment, Antheraea mylitta and Bombyx mori samples were characterized by SEM-EDX, FT-IR, XRD and TGA-DSC techniques. Preliminary cell growth behavior was carried out by culturing epidermal cells and proliferation was quantified via viability assay. Moreover, Antheraea mylitta possesses excellent cell-adhesive capability, effectively promoting cell attachment and proliferation. Antheraea mylitta serves as a delivery vehicle for cells. With all these unique features, it is expected that Antheraea mylitta mat will have wide utility in the areas of tissue engineering and regenerative medicine.

Demineralization of cocoons of Antheraea assamensis Helfer (muga) for effective reeling

Muga cocoons are evidenced of possessing heavy deposition of minerals (such as calcium oxalate) on its surface. This mineral deposition restricts reeling of muga fiber in comparison to the cocoons of mulberry silkworm. In this study, we have attempted to wash out the mineral layer using various chemical and natural agents like ethylenediaminetetraacetic acid (EDTA), potassium carbonate, citric acid, extract of Musa balbisiana (‘kolakhar’), and Citrus limon (lemon), respectively. It is observed that both the natural and chemical agents carefully removes the mineral deposition, leaving the gummy sericin substantially intact, preventing entanglement of fibroin brins, and permitting wet reeling with very minimum number of fiber breaks compared to commercial degumming. The removal of granular minerals was evidenced by surface morphology and FTIR spectroscopy of demineralized cocoon fiber. Further, the tensile strength of demineralized fiber showed superiority in contrast to sodium carbonate degummed fiber. Under the implemented experimental conditions ‘kolakhar’ functioned as the most efficient demineralizing agent amongst all. Therefore, the present study demonstrates an improved method for softening wild silk cocoons in contrast to harsh degumming for obtaining long continuous reeled fiber threads with very less number of fiber breaks and enhanced mechanical strength.

Biology and rearing performance of Actias selene Hubner (Lepidoptera: Saturniidae), a wild silk moth in Nagaland, India

Biology and rearing performance of Actias selene Hubner (Lepidoptera: Saturniidae), a wild silk moth in Nagaland, India

Oviposition and feeding behaviour of Xanthopimpla pedator (Fabricius) (Hymenoptera: Ichneumonidae) on tropical tasar silkworm, Antheraea mylitta (Drury) (Lepidoptera: Saturniidae)

Xanthopimpla pedator is a major pupal endoparasitoid of tropical tasar silkworm, Antheraea mylitta. Extensive parasitism by X. pedator results in pupal (seed) mortality and broken cocoons, which declines the wild tasar silk production. A detailed account is given on the oviposition behaviour of the female X. pedator and feeding behaviour of its immature forms in the pupa of A. mylitta. Scanning electron microscopic (SEM) details of the ovipositor of X. pedator revealed the presence of various mechano- and chemoreceptors, which regulate host discrimination and oviposition behaviour. The oviposition and feeding behaviour of X. pedator were evaluated in the field as well as in situ conditions. In addition, the invasion caused by X. pedator on A. mylitta, are also described. Host-parasitoid interactions are also discussed and recorded frame-by-frame video-graphically. The parasitoid X. pedator, arrests development and eventually the survival of A. mylitta. We also assume that parasitism by X. pedator in tasar culture is due to the microhabitat and food content of pupal host A. mylitta, which favors the development of parasitoid.