China
Africa
Explore chapters and articles related to this topic
Alkaliphilic Bacteria and Thermophilic Actinomycetes as New Sources of Antimicrobial Compounds
Published in Devarajan Thangadurai, Jeyabalan Sangeetha, Industrial Biotechnology, 2017
Suchitra B. Borgave, Meghana S. Kulkarni, Pradnya P. Kanekar, Dattatraya G. Naik
It is well known that terrestrial microorganisms, in particular the Streptomycetes, as well as Gram-positive soil bacteria of the order, Actinomycetales are the major source of antimicrobial agents. These are produced as complex secondary metabolites which result in billions of US dollars per year in sales. The soil-dwelling filamentous Streptomyces coelicolor is responsible for over half the naturally-derived antibiotics in current use today. Actinomycetes are found in a wide variety of habitats, including aquatic and terrestrial habitats and are especially abundant in soils of different types. Soil samples from various locations have been screened all over the world with the objective of isolating actinomycetes with the ability to produce bioactive compounds. However most of the screenings have concentrated on the isolation of mesophilic actinomycetes. The information on secondary metabolites produced by actinomycetes is compiled by Tabarez (2005, 2006). An immense variety of active secondary metabolites with different properties have been isolated from actinomycetes.
The enigma of environmental organoarsenicals: Insights and implications
Published in Critical Reviews in Environmental Science and Technology, 2022
Xi-Mei Xue, Chan Xiong, Masafumi Yoshinaga, Barry Rosen, Yong-Guan Zhu
The non-arsenic analogs of three arsenic-containing single-chain lipids (AsHCs, AsFAs and trimethylarsenio fatty alcohols) are rare in nature. A gene cluster involved in biosynthesis of an AsFA metabolite, predicted as either dimethylarsinoyl hydroxy fatty acid or As(V)-containing fatty acid based on the mass, was identified in Streptomyces coelicolor and Streptomyces lividans (Cruz-Morales et al., 2016). The proposed biosynthesis pathway of the AsFA metabolite is based on annotations of the genes in the cluster, where the gene annotated to encode a homolog of AroA (enolpyruvyl shikimate 3-phosphate synthase) is predicted to catalyze the first step, the formation of arsenoenolpyruvate from As(V). A mutant strain lacking the aroA gene lost the ability to produce the AsFA metabolite, partially supporting the proposed pathway, yet the entire pathway largely remains unknown (Cruz-Morales et al., 2016).