Microbial consortia exert great influence over the physiology of humans, animals, plants, and ecosystems. However, difficulty in controlling their composition and population dynamics have limited their application in medicine, agriculture, biotechnology, and the environment. The approach disclosed herein provides an effective method to dynamically control population compositions in microbial consortia, which we demonstrate in the context of co-culture fermentations for chemical production. Co-culture fermentations can improve chemical production from complex biosynthetic pathways over monocultures by distributing enzymes across multiple strains, thereby reducing metabolic burden, overcoming endogenous regulatory mechanisms, or exploiting natural traits of different microbial species. However, stabilizing and optimizing microbial sub-populations for maximal chemical production remains a major obstacle in the field. An optogenetic circuit, called OptoTA, is disclosed for regulating a toxin-antitoxin system, which enables tunability of, e.g., Escherichia coli growth using only blue light. With the disclosed system, one can control population ratios of co-cultures of, e.g., E. coli and Saccharomyces cerevisiae containing different metabolic modules of biosynthetic pathways. Results reveal that intermediate light duty cycles improve chemical production by establishing optimal co-culture populations.

Microbial consortia exert great influence over the physiology of humans, animals, plants, and ecosystems. However, difficulty in controlling their composition and population dynamics have limited their application in medicine, agriculture, biotechnology, and the environment. The approach disclosed herein provides an effective method to dynamically control population compositions in microbial consortia, which we demonstrate in the context of co-culture fermentations for chemical production. Co-culture fermentations can improve chemical production from complex biosynthetic pathways over monocultures by distributing enzymes across multiple strains, thereby reducing metabolic burden, overcoming endogenous regulatory mechanisms, or exploiting natural traits of different microbial species. However, stabilizing and optimizing microbial sub-populations for maximal chemical production remains a major obstacle in the field. An optogenetic circuit, called OptoTA, is disclosed for regulating a toxin-antitoxin system, which enables tunability of, e.g., Escherichia coli growth using only blue light. With the disclosed system, one can control population ratios of co-cultures of, e.g., E. coli and Saccharomyces cerevisiae containing different metabolic modules of biosynthetic pathways. Results reveal that intermediate light duty cycles improve chemical production by establishing optimal co-culture populations.

The present disclosure relates in some aspects to methods for analyzing a target nucleic acid in a biological sample. In some aspects, the methods involve the use of a set of oligonucleotides, for example a set of two or more oligonucleotides, wherein one or more oligonucleotides comprises one or more photoreactive nucleotides, for analyzing target nucleic acids. In some aspects, the presence, amount, and/or identity of a target nucleic acid is analyzed in situ. Also provided are oligonucleotides, sets of oligonucleotides, compositions, and kits for use in accordance with the methods.

The present disclosure relates in some aspects to methods for analyzing a target nucleic acid in a biological sample. In some aspects, the methods involve the use of a set of oligonucleotides, for example a set of two or more oligonucleotides, wherein one or more oligonucleotides comprises one or more photoreactive nucleotides, for analyzing target nucleic acids. In some aspects, the presence, amount, and/or identity of a target nucleic acid is analyzed in situ. Also provided are oligonucleotides, sets of oligonucleotides, compositions, and kits for use in accordance with the methods.

Embodiments of the present disclosure relate to nucleotides labeled with photoswitchable compounds. Also provided herein are methods and kits of using these labeled nucleotides for sequencing applications.

Embodiments of the present disclosure relate to nucleotides labeled with photoswitchable compounds. Also provided herein are methods and kits of using these labeled nucleotides for sequencing applications.

An example method includes introducing a first fluid to a flow channel of a flow cell including a working electrode having a surface that is at least partially exposed to the flow channel, the surface being unmodified or modified with a first member of a transition metal complex binding pair, whereby a linking moiety of a complex present in the first fluid chemically attaches the complex to the surface to form a temporarily modified surface of the working electrode; performing a sensing operation involving the complex of the temporarily modified surface; and applying a desorption voltage of the linking moiety to the working electrode, thereby detaching the linking moiety and regenerating the surface.

An example method includes introducing a first fluid to a flow channel of a flow cell including a working electrode having a surface that is at least partially exposed to the flow channel, the surface being unmodified or modified with a first member of a transition metal complex binding pair, whereby a linking moiety of a complex present in the first fluid chemically attaches the complex to the surface to form a temporarily modified surface of the working electrode; performing a sensing operation involving the complex of the temporarily modified surface; and applying a desorption voltage of the linking moiety to the working electrode, thereby detaching the linking moiety and regenerating the surface.

This application provides a bead with a covalently attached chemical compound and a covalently attached DNA barcode and methods for using such beads. The bead has many substantially identical copies of the chemical compound and many substantially identical copies of the DNA barcode. The compound consists of one or more chemical monomers, where the DNA barcode takes the form of barcode modules, where each module corresponds to and allows identification of a corresponding chemical monomer. The nucleic acid barcode can have a concatenated structure or an orthogonal structure. Provided are method for sequencing the bead-bound nucleic acid barcode, for cleaving the compound from the bead, and for assessing biological activity of the released compound.

This application provides a bead with a covalently attached chemical compound and a covalently attached DNA barcode and methods for using such beads. The bead has many substantially identical copies of the chemical compound and many substantially identical copies of the DNA barcode. The compound consists of one or more chemical monomers, where the DNA barcode takes the form of barcode modules, where each module corresponds to and allows identification of a corresponding chemical monomer. The nucleic acid barcode can have a concatenated structure or an orthogonal structure. Provided are method for sequencing the bead-bound nucleic acid barcode, for cleaving the compound from the bead, and for assessing biological activity of the released compound.