Nuclear matrix associated RNA datasets of posterior silk glands of Bombyx mori during 5th instar larval development

Objectives Bombyx mori is the key contributor to industrial silk production. The maximum production of silk occurs during 5th instar. The posterior silk glands in the larvae are responsible for the production of the main component of silk fibre—fibroin. The expression of genes and their regulation are dependent on the chromatin architecture. The nuclear matrix supports its structure and function by anchoring specific regions to regulate gene expression. The major constituent of the nuclear matrix, crucial to its structural and temporal maintenance, is its RNA. Therefore, the study of nuclear matrix RNA of the posterior silk glands on different days of 5th instar larval development is essential to understand its association to differential expression of genes. Data description The tissue-specific developmental association of nuclear matrix RNA (NuMat RNA) at the genome level has not been done so far for any organism. Bombyx mori, CSR2 X CSR4 is the most popular dihybrid strain in India. The nuclear matrix RNA was isolated from day 1, day 5 and day 7 of 5th instar posterior silk glands of Bombyx mori. The NuMat RNA was sequenced using Illumina platform. The reads obtained were processed and the datasets were deposited in NCBI.

Mesoscale structure development reveals when a silkworm silk is spun

Silk fibre mechanical properties are attributed to the development of a multi-scale hierarchical structure during spinning. By careful ex vivo processing of a B. mori silkworm silk solution we arrest the spinning process, freezing-in mesoscale structures corresponding to three distinctive structure development stages; gelation, fibrilization and the consolidation phase identified in this work, a process highlighted by the emergence and extinction of ‘water pockets’. These transient water pockets are a manifestation of the interplay between protein dehydration, phase separation and nanofibril assembly, with their removal due to nanofibril coalescence during consolidation. We modeled and validated how post-draw improves mechanical properties and refines a silk’s hierarchical structure as a result of consolidation. These insights enable a better understanding of the sequence of events that occur during spinning, ultimately leading us to propose a robust definition of when a silkworm silk is actually ‘spun’.

Effect of silk sericin pre-treatment on dyeability of woollen fabric

Silk fibres consist of sericin and fibroin. 20–25% of silk fibre is sericin. Sericin is biodegradable, antibacterial, and UV resistant. In this study, silk sericin protein was applied to wool fabric as a pre-treatment. Wool fabrics pre-treated with silk sericin were dyed with Eriofast Red B and Eriofast Blue 3R dyestuffs. Colour and reflectance measurements of the dyed wool samples were carried out. Washing, rubbing, light fastness properties were explored. Moreover, hydrophilicity, nitrogen content (Kjeldahl Method), FTIR and ESCA analysis were performed on the sericin applied wool fabric samples. Pre-treatment with sericin was found to increase the hydrophilicity level of wool fibres. Pre-treatment with silk sericin also increased the colour yield of wool fibre dyed with Eriofast Red B and Eriofast Blue 3R. It was determined that the wool fibre fabrics pre-treated with sericin displayed sufficient colour and colour fastness values even after dyeing at lower dyeing temperatures.

Structural and Thermal Properties of Ethiopian Eri and Mulberry Silk Fibres

Silk fibre has received attention in the biomedical sector rather than textile production because of its excellent biocompatibility properties in the past century. Although silk fibre properties are different from area to area, it has created an opportunity in the biomedical sector to develop new silk-based medical textile products. This research work aimed to study the structural, physical, mechanical, and thermal properties of Ethiopian silkworm cocoon’s filament. Eri and mulberry silk fibre properties such as morphological structure, chemical properties, linear density, filament length, tensile strength, elongation, thermal property, and luster were measured using ES ISO and ASTM standard methods. Statistical analysis result showed that eri silk fibre from Arba Minch had water removal temperature between 100°C and 125°C with a degradation temperature of around 400°C and eri silk fibre from both Addis Ababa and Awassa had an almost similar water removal temperature around 100°C and degradation temperature around 420°C. Tensile strength and elongation of both eri and mulberry silk fibres had significant differences among each region. The highest tensile strength of 4.47 cN was observed from Addis Ababa, and the highest elongation of 20.01% was found from the Arba Minch eri silk fibre. The coarser linear density of 2.496 dtex from Arba Minch and finer count of 2.392 dtex were exhibited from Awassa. Arba Minch eri silk fibre had the highest filament length of 403.04 m and the least fibre length of 399.2 m recorded at Addis Ababa, and a better whiteness (Rd) value of 58.21 was observed at Arba Minch eri silk fibre. Bivoltine and multivoltine mulberry silk fibres had an average tensile strength of 8.01 and 11.83 cN, elongation of 10.3 and 12.1%, fineness of 3.2 and 3.16 dtex, and filament length of 1208.6 and 1028.26 m, respectively, in the same place of Arba Minch. The morphological structure of eri silk fibre from each region had an almost smooth and clean surface, but bivoltine and multivoltine mulberry silk fibres were somehow rough and had spots. According to the comparison results, Ethiopian silk fibres can be utilised more in the biomedical application and competitive in the global market.

Effects of alkalisation and volume fraction reinforcement of Bombyx mori silk fibre on the flexural strength of dental composite resins

Background: Composite resins are widely used in dentistry to restore dental caries. Recently, short fibre-reinforced composite (FRC) resins have been widely used for high-stress areas, especially in posterior teeth. Bombyx mori silk fibre is under research to reinforce dental composite resin as it has good mechanical properties. Purpose: This study aims to obtain the effects of alkalisation and silk fibre volume fraction on the flexural strength of FRC. Methods: Bombyx mori silk fibres were obtained from Perhutani, Pati, Indonesia. Samples were divided into two alkalisation groups (4% and 8%). Alkalisation of the silk fibres was conducted through the scouring process in NaOH, hydrolysis (30% H2SO4) and drying. Silk fibres were then reinforced in a resin matrix. The samples were subdivided based on the fibre volume fraction reinforcements, which were 0%, 5%, 10% and 15%. Each group of samples consisted of three specimens (n = 3). Flexural strength was measured using a universal testing machine. Data were analysed by two-way ANOVA (p < 0.05) and post-hoc least significant difference test (p < 0.05). Results: The results showed the flexural strength (MPa) means of the 4% alkalisation group were 169.31 ± 54.28 (0%), 76.08 ± 43.69 (5%), 107.86 ± 40.61 (10%) and 101.99 ± 10.61 (15%). The flexural strength (MPa) means of the 8% alkalisation group were 169.31 ± 54.28 (0%), 82.62 ± 22.41 (5%), 111.07 ± 32.89 (10%) and 153.23 ± 23.80 (15%). Statistical analysis by ANOVA indicated that the fibre volume fraction affected the flexural strength of composite resins. Conclusion: It can be concluded that the volume fraction of silk fibre increases the flexural strength of composite resins, although the strength is not as high as a composite resin without fibres. However, the alkalisation percentage did not affect the flexural strength of composite resins, and there was no interaction between alkalisation percentage and fibre volume fraction with the flexural strength of composite resins.