Scaffold pore size is an important factor affecting tissue regeneration efficiency. The effect of pore size on cartilage tissue regeneration was compared by using four types of collagen porous ...scaffolds with different pore sizes. The collagen porous scaffolds were prepared by using pre-prepared ice particulates that had diameters of 150-250, 250-355, 355-425 and 425-500μm. All the scaffolds had spherical large pores with good interconnectivity and high porosity that facilitated cell seeding and spatial cell distribution. Chondrocytes adhered to the walls of the spherical pores and showed a homogeneous distribution throughout the scaffolds. The in vivo implantation results indicated that the pore size did not exhibit any obvious effect on cell proliferation but exhibited different effects on cartilage regeneration. The collagen porous scaffolds prepared with ice particulates 150-250μm in size best promoted the expression and production of type II collagen and aggrecan, increasing the formation and the mechanical properties of the cartilage.
Genome wide analysis of orthologous clusters is an important component of comparative genomics studies. Identifying the overlap among orthologous clusters can enable us to elucidate the function and ...evolution of proteins across multiple species. Here, we report a web platform named OrthoVenn that is useful for genome wide comparisons and visualization of orthologous clusters. OrthoVenn provides coverage of vertebrates, metazoa, protists, fungi, plants and bacteria for the comparison of orthologous clusters and also supports uploading of customized protein sequences from user-defined species. An interactive Venn diagram, summary counts, and functional summaries of the disjunction and intersection of clusters shared between species are displayed as part of the OrthoVenn result. OrthoVenn also includes in-depth views of the clusters using various sequence analysis tools. Furthermore, OrthoVenn identifies orthologous clusters of single copy genes and allows for a customized search of clusters of specific genes through key words or BLAST. OrthoVenn is an efficient and user-friendly web server freely accessible at http://probes.pw.usda.gov/OrthoVenn or http://aegilops.wheat.ucdavis.edu/OrthoVenn.
Tissue engineering (TE) has been used as an attractive and efficient process to restore the original tissue structures and functions through the combination of biodegradable scaffolds, seeded cells, ...and biological factors. As a unique type of scaffolds, hydrogels have been frequently used for TE because of their similar 3D structures to the native extracellular matrix (ECM), as well as their tunable biochemical and biophysical properties to control cell functions such as cell adhesion, migration, proliferation, and differentiation. Various types of hydrogels have been prepared from naturally derived biomaterials, synthetic polymers, or their combination, showing their promise in TE. This review summarizes the very recent progress of hydrogels used for TE applications. The strategies for tuning biophysical and biochemical properties, and structures of hydrogels are first introduced. Their influences on cell functions and promotive effects on tissue regeneration are then highlighted.
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•PAgT composite exhibited effective disinfection on various pathogenic bacteria.•Antimicrobial behaviors between Gram +ve and Gram −ve were comparatively studied.•Silicone ...glue-immobilized PAgT system showed excellent stability and reusability.•Photocatalysis and mechanical stress showed synergistic effect on disinfection process.•The newly immobilized catalytic system holds great potential for real water sterilization.
In this study, we reported an effective visible light-assisted photocatalytic disinfection toward various representative pathogenic bacteria over a highly reusable glue-immobilized P/Ag/Ag2O/Ag3PO4/TiO2 (PAgT) system. The results showed that the PAgT photocatalyst could rapidly kill all pathogenic bacteria isolated from real water environment, including Gram-positive (+ve) (Enterococcus sp. and Staphylococcus aureus) and Gram-negative (−ve) (Escherichia coli and Salmonella), both in single and mixed bacteria system. Compared to Gram −ve bacterium, the inactivation of Gram +ve bacterium was more resistant to the photocatalytic treatment, which was mainly ascribed to their thicker peptidoglycan layers in cell walls. In addition, using silicone glue as a binder provided a strong adhesion between the solid matrix and catalyst particles thus making the immobilized PAgT highly reusable. More strikingly, it was found that the enhanced antibacterial performance of immobilized PAgT system was due to a synergistic effect of disinfection mechanism combining the improved photocatalysis on the introduction of heterojunction structure, and the mechanical stress driven from the composite sharp edge morphology. Hence, the present results of the photocatalytic disinfection toward a broad range of pathogenic bacteria, with excellent activity, stability and reusability, reveals the possibility of the developed silicone glue-immobilized PAgT in real water sterilization.
Photothermal therapy (PTT) has attracted broad attention as a promising method for cancer therapy with less severe side effects than conventional radiation therapy, chemotherapy and surgical ...resection. PTT relies on the photoconversion capacity of photothermal agents (PTAs), and a wide variety of nanomaterials have been employed as PTAs for cancer therapy due to their excellent photothermal properties. The PTAs are systematically or locally administered and become enriched in cancer cells to increase ablation efficiency. In recent years, PTAs and three-dimensional scaffolds have been hybridized to realize the local delivery of PTAs for the repeated ablation of cancer cells. Meanwhile, the composite scaffolds can stimulate the reconstruction and regeneration of the functional tissues and organs after ablation of cancer cells. A variety of composite scaffolds of photothermal nanomaterials have been prepared to combine the advantages of different modalities to maximize their therapeutic efficacy with minimal side effects. The synergistic effects make the composite scaffolds attractive for biomedical applications. This review summarizes these latest advances and discusses the future prospects.
Exploring the antecedents that affect the team innovation performance can better promote the organization to research the potential factors to enhance the organizational innovation competitiveness. ...Drawing upon information processing theory, we develop a moderated mediation model to examine the relationship between team pro-social rule breaking and team innovation performance. A three-wave field study is constructed from two large manufacturing enterprises from 82 team leaders and their 382 subordinates in Shanghai, China. The results reveal that team pro-social rule breaking is positively related to team innovation performance through team reflexivity. In addition, the relationship between team pro-social rule breaking and team innovation performance via team reflexivity is positive only when team learning orientation is high. The implications, limitations, and future research directions of these findings are discussed.
Extracellular matrix （ECM） plays a very important role in regulating cell function and fate. It is highly desirable to fabricate biomimetic models to investigate the role of ECM in stem cell ...differentiation. In this study, arginine- glycine--aspartate （RGD）-modified gold nanoparticles （Au NPs） with tunable surface ligand density were prepared to mimic the ECM microenvironment. Their effect on osteogenic and adipogenic differentiation of human mesenchymal stem cells （MSCs） was investigated. The biomimetic Au NPs were taken up by MSCs in a ligand density-dependent manner. The biomimetic NPs with a high RGD density had an inhibitive effect on the alkaline phosphatase （ALP） activity, calcium deposition, and osteogenic marker gene expression of MSCs. Their effect on oil droplet formation and adipogenic marker gene expression was negative when RGD density was low, while their effect was promotive when RGD density was high. The biomimetic Au NPs regulated the osteogenic and adipogenic differentiation of MSCs mainly through affecting the focal adhesion and cytoskeleton. This study highlights the roles of biomimetic NPs on stem cell differentiation that could provide a meaningful strategy in fabricating functional biomaterials for tissue engineering and biomedical applications.
Fruit ripening in tomato (Solanum lycopersicum) is a complicated development process affected by both endogenous hormonal and genetic regulators and external signals. Although the role of NOR, a ...member of the NAC domain family, in mediating tomato fruit ripening has been established, its underlying molecular mechanisms remain unclear. To explore further the role of NAC transcription factors in fruit ripening, we characterized a new tomato NAC domain protein, named SlNAC4, which shows high accumulation in sepal and at the onset of fruit ripening. Various stress treatments including wounding, NaCl, dehydration and low temperature significantly increased the expression of SlNAC4. Reduced expression of SlNAC4 by RNA interference (RNAi) in tomato resulted in delayed fruit ripening, suppressed Chl breakdown and decreased ethylene synthesis mediated mainly through reduced expression of ethylene biosynthesis genes of system-2, and reduced carotenoids by alteration of the carotenoid pathway flux. Transgenic tomato fruits also displayed significant down-regulation of multiple ripening-associated genes, indicating that SlNAC4 functions as a positive regulator of fruit ripening by affecting ethylene synthesis and carotenoid accumulation. Moreover, we also noted that SlNAC4 could not be induced by ethylene and may function upstream of the ripening regulator RIN and positively regulate its expression. Yeast two-hybrid assay further revealed that SlNAC4 could interact with both RIN and NOR protein. These results suggested that ethylene-dependent and -independent processes are regulated by SlNAC4 in the fruit ripening regulatory network.
Controlling the differentiation of human mesenchymal stem cells (hMSCs) shows a great potential in regenerative medicine. Because overproduced reactive oxygen species (ROS) have an obvious inhibitory ...effect on the differentiation and functions of hMSCs, it is highly desirable to develop an effective strategy for ROS scavenging and stem cell differentiation controlling. In this study, gold nanoparticles (Au NPs) with an average size of 40 nm were conjugated with 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO) to endow them with ROS-scavenging capacity while holding the beneficial effect of Au NPs. The TEMPO-conjugated Au NPs (Au-PEG-TEMPO NPs) were used for the culture of hMSCs to investigate their effect on ROS scavenging, proliferation, and osteogenic and adipogenic differentiation of hMSCs. The Au-PEG-TEMPO NPs had a negligible influence on cell viability and proliferation of hMSCs and could effectively reduce the ROS level of hMSCs under H2O2-exposed conditions because of their excellent cellular uptake. Similar to the counterparts without surface TEMPO modification (Au-mPEG NPs), the Au-PEG-TEMPO NPs could promote the osteogenic differentiation of hMSCs, whereas they could inhibit the adipogenic differentiation of hMSCs. The results indicated that the TEMPO-conjugated Au NPs had high scavenging capacity for overproduced ROS and maintained the promotive effect of Au NPs on osteogenic differentiation of hMSCs without the inhibitory effect of free TEMPO. This study offers a promising strategy for ROS scavenging to control stem cell differentiation in stem cell transplantation and regenerative medicine.
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