Mechanochromic luminescence of 1-alkanoylaminopyrenes adsorbed onto cellulose papers

We have previously reported that crystalline samples of 1-acetylaminopyrene (AAPy), 1-octanoylaminopyrene (OAPy), and 1-stearoylaminopyrene (SAPy) exhibited mechanochromic luminescence. In the present study, we have found that these 1-alkanoylaminopyrenes adsorbed onto cellulose papers also exhibited mechanochromic luminescence; however, their behaviors were essentially different from those observed for their crystalline samples. In addition, these cellulose papers were found to exhibit reversible emission color change upon alternate exposure to ethanol and water vapors. It was suggested that 1-alkanoylaminopyrene molecules were dispersed in the paper without aggregation or crystallization and that intermolecular distance of 1-alkanoylaminopyrenes in the paper was reduced by either mechanical stress or exposure to ethanol vapor, resulting in increasing the sites where excimers could be formed and/or in enhancing the efficiencies of energy migration to reach the excimer sites

Functional peptide KP24 enhances submandibular gland tissue growth in vitro

AbstractIntroductionSalivary gland hypofunction, also known as xerostomia, occurs as a result of radiotherapy for head and neck cancer, autoimmune diseases, or aging. Xerostomia leads to oral health problems and thus affects the quality of life. Biological salivary gland tissue generated in vitro would provide an alternative mode of treatment for this disease.MethodsTo develop a novel method for modulating salivary gland tissue growth in vitro, we prepared a KP24 peptide-immobilized hydrogel sheet, wherein the peptide comprised repeating proline and lysine sequences, and evaluated the effect of this peptide on salivary gland tissue growth.ResultsWe found that the KP24 peptide has the potential to enhance glandular tissue growth in vitro. This enhancement is associated with neurite outgrowth and increasing neural innervation.ConclusionKP24 peptide modified material would be a promising material for the modulation of salivary gland tissue growth in vitro

Peptide-modified Substrate for Modulating Gland Tissue Growth and Morphology In Vitro

In vitro fabricated biological tissue would be a valuable tool to screen newly synthesized drugs or understand the tissue development process. Several studies have attempted to fabricate biological tissue in vitro. However, controlling the growth and morphology of the fabricated tissue remains a challenge. Therefore, new techniques are required to modulate tissue growth. RGD (arginine-glycine-aspartic acid), which is an integrin-binding domain of fibronectin, has been found to enhance cell adhesion and survival; it has been used to modify substrates for in vitro cell culture studies or used as tissue engineering scaffolds. In addition, this study shows novel functions of the RGD peptide, which enhances tissue growth and modulates tissue morphology in vitro. When an isolated submandibular gland (SMG) was cultured on an RGD-modified alginate hydrogel sheet, SMG growth including bud expansion and cleft formation was dramatically enhanced. Furthermore, we prepared small RGD-modified alginate beads and placed them on the growing SMG tissue. These RGD-modified beads successfully induced cleft formation at the bead position, guiding the desired SMG morphology. Thus, this RGD-modified material might be a promising tool to modulate tissue growth and morphology in vitro for biological tissue fabrication

Enhanced Recombinant Protein Productivity by Genome Reduction in Bacillus subtilis

The emerging field of synthetic genomics is expected to facilitate the generation of microorganisms with the potential to achieve a sustainable society. One approach towards this goal is the reduction of microbial genomes by rationally designed deletions to create simplified cells with predictable behavior that act as a platform to build in various genetic systems for specific purposes. We report a novel Bacillus subtilis strain, MBG874, depleted of 874 kb (20%) of the genomic sequence. When compared with wild-type cells, the regulatory network of gene expression of the mutant strain is reorganized after entry into the transition state due to the synergistic effect of multiple deletions, and productivity of extracellular cellulase and protease from transformed plasmids harboring the corresponding genes is remarkably enhanced. To our knowledge, this is the first report demonstrating that genome reduction actually contributes to the creation of bacterial cells with a practical application in industry. Further systematic analysis of changes in the transcriptional regulatory network of MGB874 cells in relation to protein productivity should facilitate the generation of improved B. subtilis cells as hosts of industrial protein production

Design of galardine analogs as putative psudolysin inhibitors based on ab initio fragment molecular orbital calculations

Pseudolysin (PLN) is a metalloproteinase secreted from bacteria that degrades extracellular proteins to produce bacterial nutrition. It is thus expected that inhibitors against PLN can suppress the growth of bacteria and their pandemic spread. In addition, since these inhibitors do not attack to bacteria directly, there is a reduced risk for producing drug-resistant bacteria. On the other hand, as PLN has large structural similarity in the active sites with human matrix-metalloproteinases (MMPs), there is a possibility that the inhibitors for PLN also inhibit MMP activity, resulting in a loss of necessary nutrients to be produced by MMPs. Therefore, it is required the agents inhibiting the activity of only PLN not MMPs. In the present study, we employed a hydroxamate compound galardin, which has a significant inhibition effect against PLN and MMP, and investigated its specific interactions with PLN/MMP at atomic and electronic levels, by use of ab initio molecular simulations. Based on the results, we proposed several derivatives of galardin and elucidated which derivatives that can bind more strongly to PLN and be putative antimicrobial agents capable of inhibiting the PLN activity

MSCs feeder layers induce SMG self-organization and branching morphogenesis.

Dysfunction of salivary glands leads to several oral health problems, including dental caries, mastication and swallowing dysfunctions and multiple oral infections. Conventional treatments for such condition fell short of providing satisfying therapeutic results. Recent advances in organ regeneration therapy which utilize tissue stem cells to fabricate bioengineered 3D organ buds, have introduced a promising therapeutic tool for full functional organ regeneration. However, finding a sustainable and easily accessible cell source for such approaches is still challenging, especially in case of severely atrophied tissues such as irradiated salivary glands. In response to this, we hypothesized that bone marrow derived mesenchymal stem cells (MSCs) could be used as feeder cells to induce salivary epithelial tissues/cells branching. Indeed, in 2D cultures, MSCs supported branching of embryonic submandibular salivary gland (SMG) epithelium. Interestingly, this enhancing effect was dependent on the initial number of MSC feeder cells. In addition, MSCs supported the self-assembly of SMG epithelial progenitor cells into well-patterned and branched 3D salivary organoids. Therefore, these findings propose MSCs as a valuable candidate cell source for induced SMG epithelial branching, which can potentially be applied in future methods for SMG regeneration approaches

Time-lapse analysis of self-driven aggregate development.

<p>(a) Frames from time-lapse <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0176453#pone.0176453.s004" target="_blank">S1 Movie</a> showing self-driven condensation of epithelial cells/MSCs aggregate into 3D cell spheroid. Time represented in hours. Scale bar: 100 μm. (b) Examination of size changes during spheroid development. The aggregate projected area rapidly decreased in the first 24 hours of culture then showed steady and gradual decline. (c) Structural analysis of dynamic morphological changes during 3D spheroid development. Red dotted line marks the closest point of the aggregate as a circle (balance state). The source movie is <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0176453#pone.0176453.s004" target="_blank">S1 Movie</a>. Aggregate circularity C was defined as 4πA divided by L², where A is the aggregate projected area and is L² the square of the contour line length. (d) Comparative analysis of size changes during whole SMG (native SMG epithelium and mesenchyme) spheroid development. Notably, the aggregate projected area decreased sharply in the first 8hours of culture then showed steady and gradual decline. (e) Comparative analysis of whole SMG aggregate morphological (circularity) changes during 3D spheroid development.</p

Peptide-modified Substrate for Modulating Gland Tissue Growth and Morphology In Vitro

In vitro fabricated biological tissue would be a valuable tool to screen newly synthesized drugs or understand the tissue development process. Several studies have attempted to fabricate biological tissue in vitro. However, controlling the growth and morphology of the fabricated tissue remains a challenge. Therefore, new techniques are required to modulate tissue growth. RGD (arginine-glycine-aspartic acid), which is an integrin-binding domain of fibronectin, has been found to enhance cell adhesion and survival; it has been used to modify substrates for in vitro cell culture studies or used as tissue engineering scaffolds. In addition, this study shows novel functions of the RGD peptide, which enhances tissue growth and modulates tissue morphology in vitro. When an isolated submandibular gland (SMG) was cultured on an RGD-modified alginate hydrogel sheet, SMG growth including bud expansion and cleft formation was dramatically enhanced. Furthermore, we prepared small RGD-modified alginate beads and placed them on the growing SMG tissue. These RGD-modified beads successfully induced cleft formation at the bead position, guiding the desired SMG morphology. Thus, this RGD-modified material might be a promising tool to modulate tissue growth and morphology in vitro for biological tissue fabrication

Morphological and structural characteristics of epithelial cell/MSCs and whole SMG cell spheroids.

<p>(a) Morphological evaluation of both epithelial cells/MSCs spheroids and whole SMG cell. Scale bars: 100 μm and 200 μm, respectively. (b) Quantitative analysis of bud’s number per spheroid. Whole SMG spheroids show significantly higher number of buds compared to epithelial cells/MSCs spheroids (* p ˂ 0.01, One-way ANOVA, Scheffé's F post-hoc test). (c) Structural analysis of cell spheroids. Left; immunofluorescence analysis of epithelial cells/MSC spheroid using antibody for specific epithelial marker PNA (green) and MSCs marker CD44 (red). CD44-positive MSCs occupied the center of the cell spheroid encircled by PNA-positive epithelial buds aligned at outer layer. Scattered CD44-positive MSCs at the most-outer layer surrounded the formed epithelial buds. (Scale bar: 100 μm). Right; whole SMG cell aggregate stained with an antibody to PNA (green), and counterstained for F-actin with rhodamine phalloidin (red) (Scale bar: 100 μm). (d) Bud size quantification in both types of spheroids. (d) Quantification analysis of cell number per bud in both types of spheroids. Buds in SMG spheroids show slight increase in cell number per bud compared to buds formed in epithelial cells/MSCs spheroids.</p