The art of design

CoIN: co-inducible nitrate expression system for secondary metabolites in Aspergillus nidulans

BACKGROUND

Sequencing of fungal species has demonstrated the existence of thousands of putative secondary metabolite gene clusters, the majority of them harboring a unique set of genes thought to participate in production of distinct small molecules. Despite the ready identification of key enzymes and potential cluster genes by bioinformatics techniques in sequenced genomes, the expression and identification of fungal secondary metabolites in the native host is often hampered as the genes might not be expressed under laboratory conditions and the species might not be amenable to genetic manipulation. To overcome these restrictions, we developed an inducible expression system in the genetic model Aspergillus nidulans.

RESULTS

We genetically engineered a strain of A. nidulans devoid of producing eight of the most abundant endogenous secondary metabolites to express the sterigmatocystin Zn(II)2Cys6 transcription factor-encoding gene aflR and its cofactor aflS under control of the nitrate inducible niiA/niaD promoter. Furthermore, we identified a subset of promoters from the sterigmatocystin gene cluster that are under nitrate-inducible AflR/S control in our production strain in order to yield coordinated expression without the risks from reusing a single inducible promoter. As proof of concept, we used this system to produce β-carotene from the carotenoid gene cluster of Fusarium fujikuroi.

CONCLUSION

Utilizing one-step yeast recombinational cloning, we developed an inducible expression system in the genetic model A. nidulans and show that it can be successfully used to produce commercially valuable metabolites.

The beauty and the morbid: fungi as source of inspiration in contemporary art

The arts have the power to irritate, to provoke and to let us think and dream about the impossible. The relationship of the arts and fungi is not immediate; however, fungi are ideal subjects for artists. They are both visible and invisible. They irritate. They evoke within each of us different feelings and inner pictures. Some are perceived as disgusting or dangerous because associated with dirt or death. Others are appreciated for their unique and delicious taste in our eating culture. Microbiologists further consider them as useful for industrial exploitation or per se as interesting because they are gratifying objects to study basic phenomena of life. To stimulate a fertile and interdisciplinary dialogue between artists and fungal scientists, we here present some examples of the inspirational powers of fungi and fungal science for contemporary art. Astonishing, poetic and perplexing artistic works could release scientific creativity and overcome the boundaries between art and science.

Let microorganisms do the talking, let us talk more about microorganisms

Microorganisms are of uttermost importance, yet in the eyes of the general public they are often associated with dirt and diseases. At the same time, microbiologists have access to and comprehensive knowledge of just a tiny minority of the microbial diversity existing in nature. In this commentary, we present these issues of public misconception and scientific limitations and their possible consequences, and propose ways to overcome them. A particular interest is directed toward the secondary metabolism of filamentous fungi as well as novel outreach activities, including so-called “science slams” and interactions between the arts and the sciences, to raise awareness about the relevance of microorganisms.