Objectives for Future Research in Understanding the Effects of Ethanol on the Gastrointestinal Tract
Victor R. Preedy, Ronald R. Watson in Alcohol and the Gastrointestinal Tract, 2017
This chapter will briefly summarize some of the effects of ethanol on the gastrointestinal tract and to identify some areas that merit further investigation. Some deficiencies in present knowledge have also been highlighted in individual chapters. Nevertheless, to mention every potential process thought to be of importance would be an enormous undertaking, particularly as there are some rapidly expanding fields and their significance in the etiology of disease is currently speculative. To circumvent such a problem, a few key disciplines that require investigation have been identified and attention is focused on protein metabolism. The terms protein synthesis, protein turnover or protein metabolism may conjure up gross physiological processes. To a certain extent this is both an over simplification and a misconception, as they also encompass molecular events. Villus atrophy, loss of contractile or membrane proteins, the reductions in the relative amounts of a single protein (i.e., a key enzyme) or groups of proteins (i.e., such as those pertaining to the subcellular organelles) all involve changes in protein pool size and thus by implication protein turnover. The latter may involve changes in mRNA encoding specific proteins or amino acid supply, the availability of initiation factors, or subcellular assembly and processing.
Power and power endurance: the explosive sports
Nick Draper, Helen Marshall in Exercise Physiology, 2014
In the section on protein metabolism in Chapter 2 the process of amino acid deamination was described. As a result of deamination the amine, or nitrogen component of an amino acid, is removed. This process enables the remaining part of an amino acid, the α-keto acid, to be metabolised to produce an alternative supply of ATP. In the adenylate deaminase reaction (ADR), with the addition of water, the amine component of AMP is removed to leave inosine monophosphate (IMP) and the amine group which forms ammonia (NH3) (Figure 9.8). The ADR reaction occurs during high-intensity exercise to reduce the buildup of AMP within the sarcoplasm. A high level of AMP would inhibit the adenylate kinase reaction and interfere with sustained ATP production.
Dietary Influence on Muscle Protein Synthesis and Hypertrophy
Peter M. Tiidus, Rebecca E. K. MacPherson, Paul J. LeBlanc, Andrea R. Josse in The Routledge Handbook on Biochemistry of Exercise, 2020
Skeletal muscle constitutes ∼40% of total body mass and plays a critical role in a multitude of mechanical and metabolic functions. Specifically, muscle serves as the principal site for amino acid (AA) storage, contributes (due to its mass) to basal metabolism, and enables locomotion and athletic performance by way of contractile activity (41). Moreover, skeletal muscle mass is, in certain situations, related to all-cause mortality (99). The size and quality of skeletal muscle decline with advancing age, which increases the risk of disease development and mobility impairment (22). Accordingly, the development, and conservation, of skeletal muscle throughout the lifespan with appropriate lifestyle habits should be a principal focus for individuals looking to maximize athletic performance and enhance quality of life with age. Skeletal muscle is a highly plastic tissue, the malleability of which involves the sensing of internal and external signals and orchestrating an appropriate adaptive response. Significant progress has been made in the field of skeletal muscle protein metabolism. As such, skeletal muscle turnover is regulated by two intricately controlled processes, muscle protein synthesis (MPS) and muscle protein breakdown (MPB) (88). The balance between these two processes determines whether skeletal muscle is built (hypertrophy) or lost (atrophy). Importantly, MPS, and to some extent MPB, can be modified by a number of physiological and environmental stimuli.
Human ESC-sEVs alleviate age-related bone loss by rejuvenating senescent bone marrow-derived mesenchymal stem cells
Published in Journal of Extracellular Vesicles, 2020
Liangzhi Gong, Bi Chen, Juntao Zhang, Yongjin Sun, Ji Yuan, Xin Niu, Guowen Hu, Yu Chen, Zongping Xie, Zhifeng Deng, Qing Li, Yang Wang
Previous studies reported that EVs can affect the biological behaviours of recipient cells by transferring the encapsulated proteins [34,35]. Therefore, we prepared proteins from hESC-sEVs (Supplementary Figure 5), and then performed LC-MS/MS analysis to identify the protein contents of hESC-sEVs. In total, 4122 proteins were identified from hESC-sEVs. 98.4% of the identified proteins could be aligned to the EV proteome database (Figure 6(a)). Enrichment analysis of GO terms by FunRich software showed that 30.8% of the proteins identified in hESC-sEVs were derived from exosomes (Figure 6(b)). The GO analysis of biological processes revealed an enrichment of proteins involved in “protein metabolism” (12.8%), “metabolism” (12.4%), “energy pathways” (12.1%), “transport” (8.6%), “cell growth and/or maintenance” (8%), and “protein modification” (0.3%) (Figure 6(c)). The GO analysis of molecular functions showed that “RNA binding” (4.3%) was a major category for hESC-sEVs proteins set. In line, “translation on regulator activity” (1.6%), “structural constituent of ribosome” (2.1%), “transporter activity” (5.5%), “GTPase activity” (2.7%) and “ubiquitin-specific protease activity” (3.6%) were the top enriched for the hESC-sEVs proteins (Figure 6(d)).
Proteomes of exosomes from HPV(+) or HPV(-) head and neck cancer cells: differential enrichment in immunoregulatory proteins
Published in OncoImmunology, 2019
Sonja Ludwig, Lukasz Marczak, Priyanka Sharma, Agata Abramowicz, Marta Gawin, Piotr Widlak, Theresa L. Whiteside, Monika Pietrowska
Analysis of gene ontology was performed to identify functional pathways associated with the detected proteins. The majority (approximately 2/3) of the detected proteins in exosomes from both HPV(+) and HPV(-) cells were cytoplasmic proteins. They were associated with six major biological functions: (a) regulation of cell growth; (b) cellular metabolism; (c) protein metabolism; (d) energy pathways; (e) cell communication and (f) signal transduction (Figure 1b). Among the proteins detected in both types of exosomes were the integrin family members involved in cell surface interactions and proteins mediating proteoglycan-syndecan signaling as well as the VEGF/VEGFR signaling networks. In general, the majority of biological pathways and processes were similarly enriched in proteins detected in HPV(+) (SCC-90) and HPV(-) (PCI-30) exosomes, as shown in the Supplementary File (Table S2). Several pathways showed statistically significant enrichment (p-value with Bonferroni correction <0.05) for either HPV(+) or HPV(-) exosomes, as shown in Figure 1c. These functional terms included an adaptive immune system or cell-extracellular matrix interactions, which were significantly overrepresented in HPV(+) exosomes, and metabolism of RNA or structural components of ribosomes, which were significantly overrepresented in HPV(-) exosomes. However, no statistically significant differences were detected between these selected sets of proteins in their contribution to the specific pathway.
Panax ginseng improves physical recovery and energy utilization on chronic fatigue in rats through the PI3K/AKT/mTOR signalling pathway
Published in Pharmaceutical Biology, 2023
Guolei Zhang, BoFan Lu, Enhui Wang, Wei Wang, Zheng Li, Lili Jiao, Hui Li, Wei Wu
The exercise-induced physical decline coincides with glycogen consumption, and increasing the storage of liver and muscle glycogen can effectively improve exercise endurance (Gonzalez et al. 2016; Zhao et al. 2018). In this study, P. ginseng significantly increased the glycogen reserves of the liver and muscles, which is consistent with the effect of P. ginseng reported in the literature (Zhuang et al. 2014). During rigorous exercise, the metabolism and oxidation of carbohydrates and fats cannot meet energy needs. Therefore, protein metabolism is mobilized to maintain the body’s exercise capacity, which produces incomplete oxidation products such as LD, FFA and BUN. The content of BUN is increased; therefore, LD, FFA and BUN levels can reflect the exercise tolerance (Jung et al. 2004). It has been reported that P. ginseng can remove or inhibit fatigue metabolites and exert an antifatigue effect (Ma et al. 2017). This study also showed that P. ginseng has an antifatigue effect, reduces LA, FFA and BUN levels, and spares glycogen consumption. Na+–K+-ATPase and Ca2+–Mg2+-ATPase activities in the process of energy utilization were critical to energy utilization (Boovarahan et al. 2021). Obviously, the activity of Na+–K+-ATPase and Ca2+–Mg2+-ATPase in the skeletal muscle of EEP-treated fatigued rats increased dramatically compared to the fatigued rats, consistent with the biochemical indicators.
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