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Mechanobiology of Heart Valves
Published in Jiro Nagatomi, Eno Essien Ebong, Mechanobiology Handbook, 2018
Joshua D. Hutcheson, Michael P. Nilo, W. David Merryman
Using porcine AV leaflets in a tension bioreactor, the affects of TGF-β1 and cyclic stretch on myofibroblast activation were studied in vitro.69 The measured outputs were αSMA, heat shock protein 47 (HSP47), type I collagen C-terminal propeptide (CICP), and TGF-β1. CICP and HSP47 are both surrogates for collagen biosynthesis.72–74 The baseline control for this study was tissue in static culture that was not treated with active TGF-β1 (Null). Tissues receiving 15% stretch for 2 weeks (Tension) showed a significant increase in myofibroblast activation and collagen synthesis over the Null group and compared to day 0 controls (Figure 10.8). The same trend was observed for tissue samples in the treated daily with 0.5 ng/mL active TGF-β1 for 2 weeks (TGF). Most interestingly, the combination of these two treatments (Tension+TGF) resulted in a very significant increase in myofibroblast activation and matrix remodeling than either independent treatment. This suggests a synergism between TGF-β1 signaling and mechanical signal transduction. Furthermore, the large increase in TGF-β1 within the tissues indicates a feed-forward mechanism in which the AVICs respond to the combination of the two stimuli by producing even more TGF-β1. In vivo, this result may translate into an autocrine/paracrine signaling mechanism by which myofibroblasts produce TGF-β1 to remain activated in times of pathologic strain and signal for the activation of other AVICs to aid in tissue remodeling. In normal valves, the AVICs remain active until repair is complete and AV homeostasis is restored.64 As discussed below, AV sclerosis may be a result of the overactivity of the AVICs resulting in a loss in AV compliance.
Role of Microbes in Environmental Sustainability and Food Preservation
Published in Ram Chandra, R.C. Sobti, Microbes for Sustainable Development and Bioremediation, 2019
Huang En, Ravi Kr. Gupta, Fangfei Lou, Sun Hee Moon
All lantibiotic precursors consist of an N-terminal leader peptide and a C-terminal propeptide. The modified precursor with the leader peptide is devoid of antimicrobial activity. Removal of the leader peptide gives rise to mature lantibiotics with activity. In class I lantibiotics, the cleavage of leader peptide is catalyzed by a serine protease, LanP, before or after the peptide is exported by the dedicated ABC-transporter, LanT. In class II lantibiotics, a multifunctional transporter, LanT (P), removes the leader peptide by its N-terminal peptidase domain during the export of the peptide (McAuliffe et al., 2001; Sahl & Bierbaum, 1998).
Biomolecules and Tissue Properties
Published in Joseph W. Freeman, Debabrata Banerjee, Building Tissues, 2018
Joseph W. Freeman, Debabrata Banerjee
Collagens are synthesized within cells in a precursor form termed procollagen. This has amino (N) and carboxyl (C) terminal non-helical ends that are about 15.0 and 10.0 nm long, respectively. Figure 3.7 is a diagram of procollagen type I molecule with amino propeptides (left-hand portion of molecule), an amino non-helical end (straight portion), a triple helical region, a carboxylic non-helical end, and a carboxylic propeptide (right-hand end of molecule). The amino (N-) and carboxylic (C-) propeptides are cleaved by specific proteases during collagen self-assembly.
Effects of anti-wrinkle and skin-whitening fermented black ginseng on human subjects and underlying mechanism of action
Published in Journal of Toxicology and Environmental Health, Part A, 2020
Jin Ju Park, Junmin An, Jung Dae Lee, Hyang Yeon Kim, Jueng Eun Im, Eunyoung Lee, Jaehyoun Ha, Chang Hui Cho, Dong-Wan Seo, Kyu-Bong Kim
The dermis, a layer of the skin, which occurs beneath the epidermis, consists primarily of connective tissues comprised mainly of fibers (collagen and elastin fibers) and extrafibrillar matrix (ground substance) (Marks and Miller 2018). Fibroblasts are the most common type of cell in dermis, which synthesize the extracellular matrix including collagen and elastin. Collagen and elastin fibers play a key role in maintenance of skin firmness and elasticity of normal skin (Bateman, Lamande, and Ramshaw 1996). Generally, collagen and elastin fibers form a three-dimensional structure. Collagen, especially type I, accounts for approximately 90% of the content of connective tissue in the skin. Collagen is formed from a precursor called procollagen, which is produced by fibroblasts. Procollagen is secreted in the form of a propeptide as peptide base sequences at the amino and carboxyl-terminal ends. The propeptide is cleaved and separated from procollagen simultaneously with collagen polymerization, which aids in folding in the endoplasmic reticulum (Oikarinen et al. 1992; Parfitt et al. 1987; Talwar et al. 1995). Therefore, the quantity of separated procollagen reflects the quantity of synthesized collagen. Connective tissue of the skin contains elastin as well as collagen. Elastin constitutes only approximately 3–4% of the connective tissue (So et al. 2007); however together with collagen, elastin maintains the shape and firmness of skin. The structure of elastin is transformed by elastase by using elastin as a substrate. Thus, an increase of elastase results in the degradation of elastin, which leads to development of wrinkles (Tsuji et al. 2001; Tsukahara et al. 2001).
Effects of anti-wrinkle and skin-whitening fermented black ginseng on human subjects and underlying mechanism of action
Published in Journal of Toxicology and Environmental Health, Part A, 2020
Jin Ju Park, Junmin An, Jung Dae Lee, Hyang Yeon Kim, Jueng Eun Im, Eunyoung Lee, Jaehyoun Ha, Chang Hui Cho, Dong-Wan Seo, Kyu-Bong Kim
The dermis, a layer of the skin, which occurs beneath the epidermis, consists primarily of connective tissues comprised mainly fibers (collagen and elastin fibers) and extrafibrillar matrix (ground substance) (Marks and Miller 2018). Fibroblasts are the most common type of cells in dermis, which synthesize the extracellular matrix including collagen and elastin. Collagen and elastin fibers play a key role in the maintenance of skin firmness and elasticity of normal skin (Bateman, Lamande, and Ramshaw 1996). Generally, collagen and elastin fibers form a three-dimensional structure. Collagen, especially type I, accounts for approximately 90% of the content of connective tissue in the skin. Collagen is formed from a precursor called procollagen, which is produced by fibroblasts. Procollagen is secreted in the form of a propeptide as peptide base sequences at the amino- and carboxyl-terminal ends. The propeptide is cleaved and separated from procollagen simultaneously with collagen polymerization, which aids in folding in the endoplasmic reticulum (Oikarinen et al. 1992; Parfitt et al. 1987; Talwar et al. 1995). Therefore, the quantity of separated procollagen reflects the quantity of synthesized collagen. Connective tissue of the skin contains elastin as well as collagen. Elastin constitutes only approximately 3–4% of the connective tissue (So et al. 2007); however together with collagen, elastin maintains the shape and firmness of skin. The structure of elastin is transformed by elastase by using elastin as a substrate. Thus, an increase of elastase results in the degradation of elastin, which leads to development of wrinkles (Tsuji et al. 2001; Tsukahara et al. 2001).
New approaches towards the discovery and evaluation of bioactive peptides from natural resources
Published in Critical Reviews in Environmental Science and Technology, 2020
Nam Joo Kang, Hyeon-Su Jin, Sung-Eun Lee, Hyun Jung Kim, Hong Koh, Dong-Woo Lee
Traditionally, peptide synthesis has been segmented into solid-phase synthesis, liquid-phase synthesis, and hybrid synthesis. These approaches have a number of advantages, such as ease of operation, easy purification, short production cycles, high-level automation, and the ability to synthesize long peptides using small quantities of amino acids (Fields, 2002). We will not discuss chemical synthesis approaches in detail here due to the availability of several excellent reviews on this topic (Bray, 2003; Palomo, 2014). Among biological alternatives of peptide synthesis, microbial fermentation and enzymatic hydrolysis are the most efficient in terms of increasing oral bioavailability, decreasing adverse effects, ensuring drug safety and efficacy, imparting protease resistance, and developing formulations (Pandey, Naik, & Vakil, 2015). Nevertheless, their components or the biological process for natural BP production has several concerns about immunogenicity or biological impurities including viruses (Cantani & Micera, 2000, 2001). Biological routes to the production of BPs derived from natural resources, referred to as natural BPs, are in great demand; these compounds will be used to combat diseases with major impacts on the functions or health of organisms, especially humans and animals. In general, these peptides are inactive within the sequence of the parent protein molecule (referred to as the propeptide) and can be liberated by gastrointestinal in vivo digestion of proteins, bacterial fermentation of natural resources, or hydrolysis by proteolytic enzymes. Several systematic approaches to standardizing the cultivation of microorganisms on food-derived plant and animal sources will increasingly require the application of modern techniques in genomics, molecular biology, biochemistry, and analytical and information sciences.