The effect of inorganic phosphate on the biosynthesis of vancomycin

Redox-active antibiotics enhance phosphorus bioavailability

Microbial production of antibiotics is common, but our understanding of their roles in the environment is limited. In this study, we explore long-standing observations that microbes increase the production of redox-active antibiotics under phosphorus limitation. The availability of phosphorus, a nutrient required by all life on Earth and essential for agriculture, can be controlled by adsorption to and release from iron minerals by means of redox cycling. Using phenazine antibiotic production by pseudomonads as a case study, we show that phenazines are regulated by phosphorus, solubilize phosphorus through reductive dissolution of iron oxides in the lab and field, and increase phosphorus-limited microbial growth. Phenazines are just one of many examples of phosphorus-regulated antibiotics. Our work suggests a widespread but previously unappreciated role for redox-active antibiotics in phosphorus acquisition and cycling.

Complex natural product production methods and options

Natural products have had a major impact upon quality of life, with antibiotics as a classic example of having a transformative impact upon human health. In this contribution, we will highlight both historic and emerging methods of natural product bio-manufacturing. Traditional methods of natural product production relied upon native cellular host systems. In this context, pragmatic and effective methodologies were established to enable widespread access to natural products. In reviewing such strategies, we will also highlight the development of heterologous natural product biosynthesis, which relies instead on a surrogate host system theoretically capable of advanced production potential. In comparing native and heterologous systems, we will comment on the base organisms used for natural product biosynthesis and how the properties of such cellular hosts dictate scaled engineering practices to facilitate compound distribution. In concluding the article, we will examine novel efforts in production practices that entirely eliminate the constraints of cellular production hosts. That is, cell free production efforts will be introduced and reviewed for the purpose of complex natural product biosynthesis. Included in this final analysis will be research efforts made on our part to test the cell free biosynthesis of the complex polyketide antibiotic natural product erythromycin.

Advances in antibiotic drug discovery: reducing the barriers for antibiotic development

Antibiotic drug discovery has been an essential field of research since the early 1900s, but the threat from infectious bacteria has only increased over the decades because of the emergence of widespread multidrug resistance. In this review, we discuss the recent advances in natural product, computational and medicinal chemistry that have reinvigorated the field of antibiotic drug discovery while giving perspective on how easily, both in cost and in expertise, these methods can be implemented by other researchers with the goal of increasing the number of scientists contributing to this public health crisis.

Old and new glycopeptide antibiotics: From product to gene and back in the post-genomic era

Glycopeptide antibiotics are drugs of last resort for treating severe infections caused by multi-drug resistant Gram-positive pathogens. First-generation glycopeptides (vancomycin and teicoplanin) are produced by soil-dwelling actinomycetes. Second-generation glycopeptides (dalbavancin, oritavancin, and telavancin) are semi-synthetic derivatives of the progenitor natural products. Herein, we cover past and present biotechnological approaches for searching for and producing old and new glycopeptide antibiotics. We review the strategies adopted to increase microbial production (from classical strain improvement to rational genetic engineering), and the recent progress in genome mining, chemoenzymatic derivatization, and combinatorial biosynthesis for expanding glycopeptide chemical diversity and tackling the never-ceasing evolution of antibiotic resistance.

Physiology of antibiotic production in actinomycetes and some underlying control mechanisms

Some of the accumulated information on the physiology and nutritional control of antibiotic production in actinomycetes can now be related to recent discoveries in the field of actinomycete molecular biology. This review focuses on aspects of genetic and metabolic control of antibiotic biosynthesis. It surveys some well established principles in the relationship between primary and secondary metabolism, and summarizes briefly the areas where progress is being made in elucidating the molecular organization of regulatory systems underlying this relationship.

Regulation of spiramycin synthesis in Streptomyces ambofaciens: effects of glucose and inorganic phosphate

The production of the 16-membered macrolide antibiotic, spiramycin, in Streptomyces ambofaciens is inhibited by glucose, 2-deoxyglucose and inorganic phosphate. The role of intracellular ATP content and phosphorylated metabolites as common regulating signals of both glucose and phosphate inhibitory effects is discussed. Two enzymatic targets of the effect of phosphate on spiramycin biosynthesis were studied. Valine dehydrogenase, the first enzyme of valine catabolism (supplier of aglycone spiramycin precursors), and alkaline phosphatase, which cleaves phosphorylated intermediates, were repressed in the presence of excess phosphate.

Metabolic regulation in tylosin-producing Streptomyces fradiae: phosphate control of tylosin biosynthesis

The effects of increased concentration of inorganic phosphate on the biosynthesis of tylosin, the level of the intracellular adenylates, the energy charge, and the activities of enzymes involved in the synthesis of tylonolide precursors were studied in Streptomyces fradiae NRRL 2702. No metabolic response was observed when elevated levels of inorganic phosphate were added in idiophase. Increased initial levels of inorganic phosphate suppressed tylosin production and markedly increased the levels of the adenylates, although the adenylate energy charge was unchanged. Higher growth and glucose uptake rates were also observed. The activities of methylmalonyl-coenzyme A carboxyltransferase (EC 2.1.3.1) and propionyl-coenzyme A carboxylase (EC 6.4.1.3) were suppressed by the increased concentration of inorganic phosphate. The results indicated that the rate of tylosin synthesis was inversely related to the absolute level of the adenylates rather than to the energy charge.