ABSTRACT
Silk-based biomaterials are featured with excellent mechanical properties, good biocompatibility and biodegradability, which contribute to their potential applications in biomedical field. The current recognition of silk protein materials in structure and function provides a basic theory for the transformation of silk protein into new types of biomaterials. In addition, exogenous sequences encoding new peptide or structural domain can be inserted into the maternal gene sequences encoding silk proteins through genetic engineering technology to synthesize novel silk-based biomaterials with unique functions. This review summarizes the current trend and development perspective of genetically engineered functional silk-based materials for biomedical applications.
Subject(s)
Biocompatible Materials , Genetic Engineering , Hydrogels , SilkABSTRACT
Tumorigenesis is a complex process that is regulated by a variety of network signals. With the continuous development of the process, tumor cells gradually exhibit lots of hallmarks.Tumor cells have the characteristics of unlimited proliferation, resistance to apoptosis, evading immune surveillance, among others. As a unique organelles, mitochondria play an important role in cellular energy metabolism, reactive oxygen species producing and apoptosis process. Particularly, mitochondria have a close relationship with tumor development. In this review, we focus on the essential role of mitochondria in tumor cells development.
Subject(s)
Animals , Humans , Energy Metabolism , Mitochondria , Metabolism , Physiology , Neoplasms , Genetics , Tumor Microenvironment , PhysiologyABSTRACT
Fhx/P25 in silkworm, Bombyx mori, one of the main components of silk fibroin, is presumed in previous reports to be expressed exclusively in the posterior silk gland (PSG) of the animal with strict territorial and developmental specificities. On the basis of a large-scale analysis ofthe silkworm EST data, it was found that Fhx/P25 gene is transcribed not only in the posterior silk gland, but in the ovary and in other tissues of the larvae at day 3 of the fifth-instar as well and that this gene has distinct transcription start sites (TSSs) in the posterior silk gland and the ovary. The TSS in the ovary is located about 115 bp upstream sequence of that in the posterior silk gland. Subsequent RT-PCR, FQ-PCR and sequencing have verified the validity of this presumption. In addition, alternative splicing is predicted in pre-mRNA of Fhx/P25 gene and confirmed by RT-PCR. In conclusion, Fhx/P25 gene is not a gene with strictly tissue-specific transcription.Complicated regulation mechanisms may exist for its transcription and expression and it may have other functions to perform.
ABSTRACT
Microsatellites or simple sequence repeats (SSRs) have been found in most organisms during the last decade. Since large-scale sequences are being generated, especially those that can be used to search for microsatellites, the development of these markers is getting more convenient. Keeping SSRs in viewing the importance of the application, available CDS (coding sequences) or ESTs (expressed sequence tags) of some eukaryotic species were used to study the frequency and density of various types of microsatellites. On the basis of surveying CDS or EST sequences amounting to 66.6 Mb in silkworm, 37.2 Mb in fly, 20.8 Mb in mosquito, 60.0 Mb in mouse, 34.9 Mb in zebrafish and 33.5 Mb in Caenorhabditis elegans, the frequency of SSRs was 1/1.00 Kb in silkworm, 1/0.77 Kb in fly, 1/1.03 Kb in mosquito, 1/1.21 Kb in mouse, 1/1.25 Kb in zebrafish and 1/1.38 Kb in C. elegans. The overall average SSR frequency of these species is 1/1.07 Kb. Hexanucleotide repeats (64.5%-76.6%) are the most abundant class of SSR in the investigated species, followed by trimeric, dimeric, tetrameric, monomeric and pentameric repeats. Furthermore, the A-rich repeats are predominant in each type of SSRs, whereas G-rich repeats are rare in the coding regions.