Fluorescence and circular dichroism spectroscopy were used to monitor the conformational transition of regenerated Bombyx mori silk fibroin (RSF) in aqueous solutions under different conditions. According to the analysis of fluorescence spectra using anilinonaphthalene-8-sulfonic acid magnesium salt (ANS) as an external probe, the destruction of the hydrophobic core prior to the secondary struc...

BNC-alginate and silk fibroin tissue-engineering scaffolds were stained with X-ray contrast agents in order to visualize internal microstructure in the native wet state with microcomputed tomography. A successful protocol employing amphiphilic contrast agents (CAs) dissolved in a waterbased staining solution was used. The CAs were then fixed to the scaffold by neutralizing their charged functio...

The nucleic acid sequence bank now contains 161 mRNAs, 43 new genes are added. One sequence, that of B. mori fibroin, is dropped due to uncertainty on the starting point for translation. Frequencies of all codons are given for each gene added and for each genome type in the total bank. A new series of correspondence analyses on codon use is presented, substantiating the genome hypothesis. Inter...

Biomineralization research on mollusc shells has mostly focused on nacre formation. Chitin, silk fibroin protein, and acidic macromolecules are important components for shell formation. Although the principle concept behind shell calcification was developed many years ago, the individual components have not been well scrutinized. Besides that, Mollusca are the second largest invertebrate phylum...

This work validates an in vitro observation that silk peptides derived from the α-chymotrypsin digestion of fibroin heavy chain promote wound healing properties. A molecular level evidence of binding of these peptide fragments to growth factors, their receptors and the corresponding ligand-receptor complexes has been provided. The strengths of interactions and possible conformational changes ca...

There are two microtubule systems in the posterior silk gland cells. One is a radial microtubule system in which the microtubules run radially from the basal to the apical cytoplasm and in which fibroin globules (secretory granules of fibroin) and mitochondria are arranged along these microtubules, thus composing a "canal system" which is assumed to be responsible for the intracellular transpor...

Native silk fibroin (NSF) is a unique biomaterial with extraordinary mechanical and biochemical properties. These key characteristics are directly associated with the physical transformation of unstructured, soluble NSF into highly organized nano- and microscale fibrils rich in β-sheet content. Here, it is shown that this NSF fibrillation process is accompanied by the development of intrinsic f...

Evidence is presented here that cupric ions play a part in the natural spinning of Bombyx mori silk. Proton induced X-ray emission studies revealed that the copper content increased from the posterior part to the anterior part of silk gland, and then further increased in the silk fiber. Spectrophotometric analysis demonstrated that cupric ions formed coordination complexes with silk fibroin cha...

Sericin and fibroin are the two major proteins in the silk fibre produced by the domesticated silkworm, Bombyx mori. Fibroin has been extensively investigated as a biomaterial. We have previously shown that fibroin can function successfully as a substratum for growing cells of the eye. Sericin has been so far neglected as a biomaterial because of suspected allergenic activity. However, this mis...

The degradation behavior of silk fibroin biomaterials in human body is definitely vital for the growth of tissues. Therefore, an investigation to regulate the degradation behaviors of silk fibroin films by changing the degree of cross-linking is presented in this paper. The in-vitro experiments in the simulated human body environment showed that the degradation rate of cross-linked silk fibroin...