Antibiotics from Marine Bacteria

Antarmycins: Discovery, Biosynthesis, Anti-pathogenic Bacterial Activity, and Mechanism of Action from Deep-Sea-Derived Pseudonocardia antarctica

The rapid emergence of antimicrobial-resistant pathogenic microbes has accelerated the search for novel therapeutic agents. Here we report the discovery of antarmycin A (1), an antibiotic containing a symmetric 16-membered macrodiolide core with two pendant vancosamine moieties, one of which is glucosylated, from deep-sea-derived Pseudonocardia antarctica SCSIO 07407. The biosynthetic gene cluster of 1 was identified on a giant plasmid featuring transferable elements. In-depth biosynthetic investigation enabled us to (i) identify a set of seven genes associated with the product of the vancosamine moiety; (ii) discover two glycosyltransferases dedicated to the transfer of pendant sugars; and (iii) isolate rhamnose-modified antarmycin B (2) and a deglucosylated derivative antarmycin C (3) from genetically engineered mutant strains. Antibacterial assays revealed that 1 displays superior antibacterial properties with potent in vitro activities against the critical priority pathogens, multidrug-resistant Enterococcus faecium and methicillin-resistant Staphylococcus aureus, fast bacterial killing, insusceptibility to antimicrobial resistance, and high in vivo efficiency in infection models. Mechanistic investigations revealed that 1 disrupts the bacterial cell membrane through a mechanism involving interactions between the vancosamine moieties and membrane-embedded phosphatidylglycerol/phosphatidylethanolamine. The results provide insights into the biological generation of vancosamine in natural products and demonstrate the potential of 1 as an effective lead to address the growing antimicrobial resistance threats.

Study of marine microorganism metabolites: new resources for bioactive natural products

The marine environment has remained a source of novel biological molecules with diversified applications. The ecological and biological diversity, along with a unique physical environment, have provided the evolutionary advantage to the plant, animals and microbial species thriving in the marine ecosystem. In light of the fact that marine microorganisms frequently interact symbiotically or mutualistically with higher species including corals, fish, sponges, and algae, this paper intends to examine the potential of marine microorganisms as a niche for marine bacteria. This review aims to analyze and summarize modern literature data on the biotechnological potential of marine fungi and bacteria as producers of a wide range of practically valuable products (surfactants, glyco-and lipopeptides, exopolysaccharides, enzymes, and metabolites with different biological activities: antimicrobial, antitumor, and cytotoxic). Hence, the study on bioactive secondary metabolites from marine microorganisms is the need of the hour. The scientific novelty of the study lies in the fact that for the first time, the data on new resources for obtaining biologically active natural products - metabolites of marine bacteria and fungi - were generalized. The review investigates the various kinds of natural products derived from marine microorganisms, specifically focusing on marine bacteria and fungi as a valuable source for new natural products. It provides a summary of the data regarding the antibacterial, antimalarial, anticarcinogenic, antibiofilm, and anti-inflammatory effects demonstrated by marine microorganisms. There is currently a great need for scientific and applied research on bioactive secondary metabolites of marine microorganisms from the standpoint of human and animal health.

Overcoming Antibiotic Resistance in Microorganisms: Molecular Mechanisms

This issue of the Biochemistry (Moscow) journal presents reviews and experimental articles on the new strategies for solving the problem of antibiotic resistance and on the search for novel antimicrobial preparations using the methods of molecular biology, genetics, and nanotechnology. A wide variety of scientific approaches and successful (as a rule) research results give hope for overcoming microbial antibiotic resistance in the fight against infectious diseases.

Screening of Marine Bioactive Antimicrobial Compounds for Plant Pathogens

Plant diseases have been threatening food production. Controlling plant pathogens has become an important strategy to ensure food security. Although chemical control is an effective disease control strategy, its application is limited by many problems, such as environmental impact and pathogen resistance. In order to overcome these problems, it is necessary to develop more chemical reagents with new functional mechanisms. Due to their special living environment, marine organisms have produced a variety of bioactive compounds with novel structures, which have the potential to develop new fungicides. In the past two decades, screening marine bioactive compounds to inhibit plant pathogens has been a hot topic. In this review, we summarize the screening methods of marine active substances from plant pathogens, the identification of marine active substances from different sources, and the structure and antibacterial mechanism of marine active natural products. Finally, the application prospect of marine bioactive substances in plant disease control was prospected.