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Marine Algal Secondary Metabolites Are a Potential Pharmaceutical Resource for Human Society Developments
Published in Se-Kwon Kim, Marine Biochemistry, 2023
Somasundaram Ambiga, Raja Suja Pandian, Lazarus Vijune Lawrence, Arjun Pandian, Ramu Arun Kumar, Bakrudeen Ali Ahmed Abdul
The most of phyla as well as more than 90% of all living classification of organisms may be identified in the marine ecosystem due to its tremendous biodiversity. A marine enzyme could be a one-of-a-kind protein component that has never been detected in a terrestrial species, or it could be a well-known enzyme with novel features from a terrestrial origin. Furthermore, because the seas cover well over 70% of the surface of the planet, they contain a vast amount of natural products and novel biologically active molecules. Marine sources provide the most peptides and natural small molecules because marine sources account for half of all world biodiversity. Antimicrobial peptides are produced by the majority of marine species.
Order Blubervirales: Core Protein
Published in Paul Pumpens, Peter Pushko, Philippe Le Mercier, Virus-Like Particles, 2022
Paul Pumpens, Peter Pushko, Philippe Le Mercier
It is an unexpected and intriguing finding that the HBc peptide 147–183 representing the arginine rich domain (ARD) of the HBc molecule possesses broad spectrum anti-Gram positive and anti-Gram negative microbial activity (including some multidrug resistant microorganisms) at micromolar concentrations (Chen HL et al. 2013, 2016). The antimicrobial activity is specific and becomes apparent by membrane permeabilisation or DNA binding. The sequences HBc153–176 or HBc147–167 were necessary and sufficient for antimicrobial activity against Pseudomonas aeruginosa and Klebsiella peumoniae. The introduction of such promising antimicrobial peptides would be currently important, as overall microbial resistance to antibiotics is rapidly growing.
Secreted effectors of the innate mucosal barrier
Published in Phillip D. Smith, Richard S. Blumberg, Thomas T. MacDonald, Principles of Mucosal Immunology, 2020
Michael A. McGuckin, Andre J. Ouellette, Gary D. Wu
Antimicrobial peptides collectively form a diverse population of gene-encoded protein effectors with selective microbicidal effects against bacteria and fungi. Varied epithelia release antimicrobial peptides onto mucosal surfaces, and evidence increasingly implicates them as components of a biochemical barrier against microbial challenges. Although antimicrobial peptide primary structures vary greatly (Figure 4.5), they have broad-spectrum microbicidal activities in vitro, generally at low micromolar concentrations, and most are 5 kDa or less, cationic at neutral pH, and amphipathic. Mammalian antimicrobial peptide structures range from linear, disordered peptides that form α-helices in membrane-mimetic hydrophobic environments to molecules such as defensins which consist of antiparallel β-sheet-containing peptides that are constrained by up to four disulfide bonds. Certain antimicrobial peptides may be expressed constitutively or they may be inducible by exposure to bacteria or microbial antigens. Most antimicrobial peptides kill their target cells by peptide-mediated membrane disruption, creating defects that dissipate cellular electrochemical gradients, leading to microbial cell death. Despite their diverse primary, secondary, and tertiary structures, their amphipathicity enables the peptides to interact with and disrupt microbial cell membranes. There are two major families of antimicrobial peptides in mammals: cathelicidins and defensins (see Figure 4.5).
Promising treatment strategies to combat Staphylococcus aureus biofilm infections: an updated review
Published in Biofouling, 2020
P. S. Seethalakshmi, Riya Rajeev, George Seghal Kiran, Joseph Selvin
NO can inhibit biofilm formation at high concentrations, therefore NO-releasing compounds have been evaluated for anti-biofilm strategies (Jardeleza et al. 2011). One of the main complications in its clinical application is the unavailability of a delivery system that can support its localized and systemic delivery in therapy (Saraiva et al. 2011). Antimicrobial peptides like japonicin-2LF, phylloseptin-PTa, and synthetic peptides like PS1-2 have been evaluated for anti-biofilm activities, and are proven to be highly effective under in vivo conditions (Galdiero et al. 2019; Park et al. 2019). The drawbacks of antimicrobial peptides in clinical therapy include ecological toxicities and their instability in human body fluids (Galdiero et al. 2019). Enzymes targeting the matrix of biofilms like dispersin B, DNase, lysostaphin, proteinase K, and trypsin are effective in dispersing biofilms of S. aureus (Kiedrowski and Horswill 2011). The use of enzymes as anti-biofilm agents include certain limitations such as high cost, and also the dispersal of cells from biofilm due to enzymatic activity can lead to infections when used under in vivo conditions (Kaplan 2009).
Salivary human beta-defensins and cathelicidin levels in relation to periodontitis and type 2 diabetes mellitus
Published in Acta Odontologica Scandinavica, 2020
Dogukan Yilmaz, Ali Orkun Topcu, Emine Ulku Akcay, Mustafa Altındis, Ulvi Kahraman Gursoy
Antimicrobial peptides are small cationic molecules, which exist in almost all organisms [1]. There are over 45 antimicrobial peptides found in human body, of these human beta-defensins (hBDs) and cathelicidin (LL-37) play important role to establish homeostasis [2]. In the oral cavity, hBD 1-3 and LL-37 are found in gingival epithelium, gingival crevicular fluid (GCF) and saliva [3,4]. hBDs and LL-37 are multifunctional peptides and besides their well-known antimicrobial effect, they contribute to innate and adaptive immunity by enhancing phagocytosis, suppressing production of proinflammatory cytokines, and by regulating complement system [5]. They act as chemoattractants for immune cells and stimulate wound healing and angiogenesis [6]. Despite their well-defined effects on immunity, the question of how periodontitis and related factors do regulate the salivary antimicrobial peptides levels is left unexplained [7–10].
Risankizumab for the treatment of moderate to severe psoriasis
Published in Expert Opinion on Biological Therapy, 2019
Andrea Chiricozzi, Luca Antonioli, Salvatore Panduri, Matteo Fornai, Marco Romanelli, Corrado Blandizzi
Various immune cells are able of producing and/or secreting IL-17A. Firstly, T helper cells expressing IL-17A, the so-called Th17 cells, were identified as the most relevant sources of IL-17A in psoriasis and, in addition to this, they are also able to produce also IL-17F and IL-17A/IL-17F heterodimers. Nevertheless, other immune cells, ranging from CD8+ T cells (Tc17 cells) to γδ T cells, innate lymphoid cells 3 (ILC3), mast cells, and neutrophils, have been subsequently described as potential sources of IL-17A leading to the characterization of a large pool of cells markedly infiltrating the psoriatic skin lesions explaining the IL-17A high expression levels detected in skin, serum and tear liquid of psoriatic patients [7]. IL-17A can induce a potent inflammatory response through the activation of tissue fibroblasts, endothelial cells, neutrophils and, in particular, keratinocytes, thus generating reverberating loops that sustain and boost skin inflammation. Skin cells secreting pro-inflammatory cytokines (IL-1β, TNF, IL-17C), antimicrobial peptides (β-defensins, S100A proteins, cathelicidin), chemoattractants, such as CC chemokine ligand 20 (CCL20), chemokine C-X-C motif ligands (CXCLs), and endothelial adhesion molecules (i.e. ICAM-1), stimulate the recruitment and migration of inflammatory cells at the lesional sites [8].