The Extremophilic Actinobacteria: From Microbes to Medicine

Abstract

Actinobacteria constitute prolific sources of novel and vital bioactive metabolites for pharmaceutical utilization. In recent years, research has focused on exploring actinobacteria that thrive in extreme conditions to unearth their beneficial bioactive compounds for natural product drug discovery. Natural products have a significant role in resolving public health issues such as antibiotic resistance and cancer. The breakthrough of new technologies has overcome the difficulties in sampling and culturing extremophiles, leading to the outpouring of more studies on actinobacteria from extreme environments. This review focuses on the diversity and bioactive potentials/medically relevant biomolecules of extremophilic actinobacteria found from various unique and extreme niches. Actinobacteria possess an excellent capability to produce various enzymes and secondary metabolites to combat harsh conditions. In particular, a few strains have displayed substantial antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA), shedding light on the development of MRSA-sensitive antibiotics. Several strains exhibited other prominent bioactivities such as antifungal, anti-HIV, anticancer, and anti-inflammation. By providing an overview of the recently found extremophilic actinobacteria and their important metabolites, we hope to enhance the understanding of their potential for the medical world.

Streptomyces, Greek Habitats and Novel Pharmaceuticals: A Promising Challenge

“…Actinobacteria, which include Streptomyces, are dominant in arid environments [56], which explains why they are easily isolated from Greek soils. In addition, Greece contains deep seas, hot springs, volcanic environments, caves and salt lakes, all of which may host rare, important or extremophile streptomycetes, which are of particular interest [2,57].…”

“…Bacteria belonging to the genus Streptomyces are major producers of natural products; it has been estimated that 45% of metabolites from microbial sources [1] or about 17% of all known active secondary metabolites [2] originate from this genus, which contains over 800 species [3]. It is estimated that each strain has the potential to produce on average more than 30 secondary metabolites [4].…”

Beyond Soil-Dwelling Actinobacteria: Fantastic Antibiotics and Where to Find Them

“…Over the last 20 years, hundreds of secondary metabolites have been isolated from organisms dwelling in hypersaline, arid deserts, permafrost and artic settings, deep sea trenches, hot springs, mine waste pits and many other extreme environments. For an exhaustive report of all the natural products isolated from extremophilic and extremotolerant microorganisms please refer to historic and recent reviews on the topic [ 302 , 432 , 433 , 434 , 435 , 436 ]. An inspection of the literature reveals that most of the molecules described to date are produced by fungi and Actinobacteria.…”

Streptomyces sp.—A Treasure Trove of Weapons to Combat Methicillin-Resistant Staphylococcus aureus Biofilm Associated with Biomedical Devices

“…Given the difficulty in eradicating biofilm infections and the limited choices of effective antibiofilm agents in the clinic, efforts are underway to search for and develop approaches to disrupt biofilms, rendering them susceptible to treatment. To search for effective antibiofilm agents, natural products continue to be an important source of drug leads [9,10]. Over the last four decades, more than half of approved drugs under the small molecules category were natural products or directly derived from natural products, while only 33% of the approved drugs were totally synthesized without any natural inspiration [11].…”