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Family Caulimoviridae
Published in Paul Pumpens, Peter Pushko, Philippe Le Mercier, Virus-Like Particles, 2022
Paul Pumpens, Peter Pushko, Philippe Le Mercier
By analogy with the typical members of the order Ortervirales, the caulimoviruses also possess a homologous aspartate protease domain in their polymerase polyprotein (see Krupovic et al. 2018 for references) but lack an integrase and long terminal repeats (LTRs). However, RT-based phylogenies consistently classify these plant-infecting viruses as a sister clade of the metaviruses (compare the genome structures in the corresponding figures of Chapter 35 and here). As a result, Krupovic et al. (2018) proclaimed that the encapsidation of a DNA genome and not of a RNA genome is a homoplasious trait and, therefore, is not a reliable criterion for the current ICTV classification.
Proteases as Biocatalysts for the Synthesis of Model Peptides
Published in Willi Kullmann, Enzymatic Peptide Synthesis, 1987
Pepsin, a protease found in the gastric juice, is the best-known member of the family of the so-called “acid proteases”. Since the β-carboxylate functions of two aspartic acid residues are involved in its catalytic mechanism,86 pepsin, which exhibits a pH optimum ranging from 2 to 3, is also designated as an aspartate protease. Although it is considered a protease of broad structural specificity, pepsin elicits a striking preference for those substrates whose P1- and -positions are occupied by a phenylalanine- and an aromatic amino acid residue, respectively.87 There still exist some uncertainties about the molecular mechanisms of the peptic catalysis. In particular, the question of whether or not an intermediate acyl-enzyme- and/or an imino-enzyme complex is formed during the catalytic process has not yet been conclusively resolved.86
Progress in the study of nutritional status and selenium in dialysis patients
Published in Annals of Medicine, 2023
Meiran Cao, Shuai Zheng, Wenhua Zhang, Guicai Hu
Why does acidosis accelerate protein catabolism and exacerbate malnutrition in CKD patients? The mechanism of this was shown in a study by Bailey et al. [84] in 1996, who suggested that metabolic acidosis exacerbates malnutrition in CKD patients by activating the ubiquitin-proteasome system (UPS) to increase protein catabolism. A recent study [85] shed new light on the mechanism and stated that cysteine aspartate protease-3 (Caspase-3) also plays a role. The researchers found that caspase-3 cleaves myosin and myogenic fibers, providing a suitable substrate for UPS-mediated proteolysis. In addition, caspase-3 can also activate 26S proteinosome-mediated protein decomposition by cleaving subunits of 19S proteinosome particles (Rpt2 and 6). Therefore, these tests reveal that the presence or absence of acidosis is closely related to good or bad nutritional status of the patient, and that correction of acidosis in the patient is beneficial for improvement of his nutritional status.
Omentin-1: a newly discovered warrior against metabolic related diseases
Published in Expert Opinion on Therapeutic Targets, 2022
Aizhen Zhao, Haoxiang Xiao, Yanli Zhu, Shuai Liu, Shaofei Zhang, Zhi Yang, Luyang Du, Xiyang Li, Xiaochen Niu, Changyu Wang, Yang Yang, Ye Tian
Apoptosis is a process of programmed cell death controlled by genes and it is characterized by blistering of the cell membrane, shrinkage of the cells, condensation of the chromatin, breakage of the DNA, and rapid phagocytosis of the cell debris by neighboring cells [27]. Some compelling evidence from cardiomyocyte studies indicates that omentin-1 can inhibit cardiomyocyte apoptosis in diverse ways. Cardiomyocyte apoptosis plays a pivotal role in the pathogenesis of many cardiovascular diseases, and the extent and rate of cardiomyocyte loss are the decisive factors in the degree of morbidity and mortality [28]. Cysteine aspartate protease-3 (caspase-3) is an important mediator of apoptosis and can catalyze the specific cleavage of many key proteins in cells [29]. Kazama et al. hold the view that omentin-1 inhibits the induction of caspase-3 expression in H9c2 cells by doxorubicin, thus inhibiting cardiomyocyte apoptosis [25]. In addition, omentin-1 can counteract endoplasmic reticulum (ER) stress and prevent cardiomyocyte apoptosis, reflecting that omentin-1 treatment reduces the susceptibility to docetaxel-induced cardiotoxicity [30]. Omentin-1 also protects cardiomyocytes from apoptosis through AMPK-dependent and protein kinase B (Akt/PKB)-dependent mechanisms [31]. These findings suggest a close link between omentin-1 and cardiomyocyte apoptosis involving cardioprotection, which suggests that targeting omentin-1 in the treatment of heart diseases might be an effective approach.
Drynaria fortunei improves lipid profiles of elderly patients with postmenopausal osteoporosis via regulation of Notch1-NLRP3 inflammasome-mediated inflammation
Published in Gynecological Endocrinology, 2022
Lin Lu, Zhi Wang, Hanqing Zhang, Tongou Liu, Hong Fang
Drynaria fortunei, alternatively known as Rhizoma drynariae, Gusuibu, or Qianggu Jiaonang, is a traditional Chinese herb medicine used to treat of PMOP [7–9]. A meta-analysis including 846 patients revealed that a combination of Drynaria fortunei and conventional therapy is superior to conventional therapy alone in improving BMD [10,11]. However, to date, few studies explored whether Drynaria fortunei plays a role in regulating lipid levels and how the mechanism is in elderly patients with coexisting PMOP and dyslipidemia. Nucleotide-binding oligomeric domain-like receptor family, pyrin domain containing 3 (NLRP3) is a pivotal member in inflammasome and is mainly located on monocytes and lymphocytes. NLRP3 inflammasome is composed of NLRP3, apoptosis-associated speck-like protein containing a CARD (ASC) and cysteine-requiring aspartate protease-1 (caspase-1) [12,13]. Once NLRP3 inflammasome is activated, inflammatory cascades, such as interleukin (IL)-1β and IL-18 would be initiated and contribute to development of many diseases [14]. Therefore, this study aimed to explore whether Drynaria fortunei improves plasma lipid levels via Notch1-NLRP3 inflammasome-related pathways.