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Streptomyces: A Potential Source of Natural Antimicrobial Drug Leads
Published in Mahendra Rai, Chistiane M. Feitosa, Eco-Friendly Biobased Products Used in Microbial Diseases, 2022
Mahmoud A. Elfaky, Hanaa Nasr, Ilham Touiss, Mohamed L. Ashour
In the early 1940s, Waksman and Henrici first described the genus Streptomyces (Williams et al. 1983). It was included in the family Streptomycetaceae (Arai 1997) based on physiological and morphological characteristics. Furthermore, some other features, such as the cell wall chemical composition, including the phospholipids/peptidoglycan type, fatty acid chains and the 16S rRNA sequence, are very useful in the taxonomy of this genus (Kämpfer et al. 2008). The genus Streptomyces represents the only member of the family Streptomycetaceae that belongs to Actinobacteria phylum and is classified in Actinomycetales order placed in the class Actinobacteria (Anderson and Wellington 2001). However, Streptomyces is among the richest taxonomic components of known actinomycetes in terms of the number of discovered species (Bhattacharyya et al. 1998), with more than 500 species producing approximately two thirds of the known natural antibiotics (Mohanraj and Sekar 2013). Streptomyces are aerobic, Gram-positive, but not acid-fast bacteria that are also characterized by high guanine/cytosine content (> 70%) (Reza Dehnad et al. 2010) and can grow in different environments (Maleki et al. 2013).
Diversity of Endophytes and Biotechnological Potential
Published in Luzia Valentina Modolo, Mary Ann Foglio, Brazilian Medicinal Plants, 2019
Daiani Cristina Savi, Chirlei Glienke
The search for interesting biological activity from microorganisms has been the basis for the development of several biotechnological applications, mainly in the pharmaceutical and agricultural industries (Vitorino and Bessa, 2017). The most promising compounds in the clinic for treatment of bacterial infections were isolated from microorganisms, such as penicillin isolated from Penicillium digitatum (Laich et al., 2002); vancomycin produced by Streptomyces orientalis (Levine, 2006); streptomycin isolated from Streptomyces griseus and erythromycin produced by Saccharopolyspora erythraea (Donadio et al., 1996), among several others. Besides the high exploration of microorganisms for active compounds in the past, studies have shown that unknown species and genetically different strains are still abundant in nature, and natural products remain the most promising source for new compounds (Monciardini et al., 2014).
Mechanisms of Anticancer Drugs
Published in John C Watkinson, Raymond W Clarke, Louise Jayne Clark, Adam J Donne, R James A England, Hisham M Mehanna, Gerald William McGarry, Sean Carrie, Basic Sciences Endocrine Surgery Rhinology, 2018
Most antitumour antibiotics have been produced from bacterial and fungal cultures (often Streptomyces species). They affect the function and synthesis of nucleic acids in different ways: Anthracyclines (e.g. doxorubicin, daunorubicin, epirubicin) intercalate with DNA and affect the topoisomerase II enzyme. This DNA gyrase splits the DNA helix and reconnects it to overcome the torsional forces that would interfere with replication. The anthracyclines stabilize the DNA topoisomerase II complex and thus prevent reconnection of the strands.Actinomycin D intercalates between guanine and cytosine base pairs. This interferes with the transcription of DNA at high doses. At low doses DNA-directed RNA synthesis is blocked.Bleomycin consists of a mixture of glycopeptides that cause DNA fragmentation.Mitomycin C inhibits DNA synthesis by cross-linking DNA, acting like an alkylating agent.
Actinomycetoma by Actinomadura madurae. Clinical and therapeutic characteristics of 18 cases with two treatment modalities
Published in Journal of Dermatological Treatment, 2022
Alexandro Bonifaz, Andrés Tirado-Sánchez, Denisse Vázquez-González, Leonel Fierro-Arias, Javier Araiza, Gloria M. González
The diagnosis of actinomycetomas due to A. madurae is confirmed with the observation of grains on direct examination, or histopathologically, requiring confirmation by culture (13–15). Actinomycetoma is susceptible to several chemotherapeutic agents, however, the response is variable and related to several factors such as extent and duration of the disease, bone involvement, and the treatment used. Moreover, the low-rates of treatment response are also due to the severe fibrosis, with inadequate access to the lesion and the low sensitivity of the microorganism to different antibiotics (10,12). Treatment regimen includes at least two medications for extended periods. One of the most widely used schemes for A. madurae includes sulfamethoxazole-trimethoprim (TMP/SMX) + DDS, with variable results (16). Maghoub (17) added streptomycin to the management of actinomycetomas due to Actinomadura sp. and Streptomyces sp, with improvement the efficacy in both cases (18). In recent years, Negroni et al. (19), showed good results with the use of TMP/SMX + ciprofloxacin in actinomycetoma, although currently studies with this scheme are scarce.
Maculosin, a non-toxic antioxidant compound isolated from Streptomyces sp. KTM18
Published in Pharmaceutical Biology, 2021
Babita Paudel, Rukusha Maharjan, Prajwal Rajbhandari, Niraj Aryal, Saefuddin Aziz, Keshab Bhattarai, Bikash Baral, Rajani Malla, Hari Datta Bhattarai
Streptomyces are Gram-positive bacteria that are found in various environmental conditions and have a filamentous mycelium similar to fungi. Phylogenetically, Streptomyces is a part of Actinobacteria, with high GC-rich (70%) content. Most of them are ubiquitous and highly versatile soil-dwelling saprophytes known to produce diverse secondary metabolites, many of which are well-known antibiotics (Omura et al. 2001; Khan et al. 2011). Antioxidant activities of 30 strains of rare Actinomycetes were reported (Mohammadipanah and Momenilandi 2018) without characterizing the active molecules. Similarly, the broth extract of Streptomyces carpaticus displayed a significant DPPH free radical scavenging activity (IC50, 84.5 µg/mL) (Subramanian et al. 2017); however, the active molecule was not characterized. Thus, besides antibiotics, Streptomyces could be a promising source of antioxidant compounds.
Auto-reactivity against gut bacterial peptides in patients with late-onset diabetes
Published in Autoimmunity, 2020
Mohammad Sajid, Krishna Biswas, Harpreet Singh, Sapna Negi
Gut microbes can come in contact with the immune system due to damage in the gut barrier and modulate host immunity, thereby can generate auto-immunity. This auto-immunity may give rise to metabolic disorders. In addition, impairment of the gut barrier was displayed in autoimmune diseases like T2D and coeliac disease [31,32]. The diabetic individuals showed increased intestinal permeability which is linked with the pathogenesis of diabetes [33,34]. In addition, aging or gut microbiota composition can induce gut leakage resulting in the transport of exogenous antigens and thereby damaging pancreatic β–cells [35]. For instance, the administration of bafilomycin-A1 from Streptomyces sp. diminishes glucose tolerance, decreases islet size, and reduces relative β-cell mass [36]. Further, gut barrier permeability enables increased transport of lipopolysaccharide (LPS) to the host which can destroy β–cells of pancreatic islets and provoke insulin resistance [37,38].