Engineered genetic enteric sensor bacteria and uses thereof

1. An engineered bacteria comprising a memory circuit comprising:

a. a bacteriophage-based cl/Cro-reporter gene-based memory element comprising:

i) a bacteriophage gene sequence of cl;

ii) a bacteriophage gene sequence of Cro; and

iii) a reporter gene,

wherein the cl and the Cro are arranged in a genetic toggle switch, and wherein the reporter gene is arranged downstream and operably linked to Cro;

b. an inducible Cro-based trigger element comprising:

iv) a bacteriophage gene sequence of a second Cro sequence distinct from the Cro sequence in the memory element; and

v) an inducible promoter,

wherein the second Cro sequence is operably linked to the inducible promoter, and

wherein the inducible promoter is responsive to a trigger agent, wherein the memory circuit is integrated into the genome of the bacteria.

2. The engineered bacteria of claim 1 , wherein the memory circuit in maintained in the bacteria without antibiotic selection.

3. The engineered bacteria of claim 1 , wherein the memory circuit comprises lambda phage sequences of cl and Cro.

4. The engineered bacteria of claim 1 , wherein the reporter gene is selected from the group consisting of β-galactosidase (LacZ) , chloramphenicol acetyltransferase (CAT), neomycin phosphotransferase (G418), bacteria luciferase (LuxAB), green fluorescent protein (GFP), alkaline phosphatase (PhoA), and p-glucuronidase (GUS).

5. The engineered bacteria of claim 1 , wherein the inducible promoter is responsive to tetracycline, tetrathionate, reactive oxygen species, diA and hydrogen sulfite gas (H 2 S).

6. A method of detecting a target in the gastrointestinal tract or colon of a subject, the method comprising

administering the engineered bacterium of claim 1 to the subject, wherein the inducible promoter is responsive to the target;

collecting a sample of fecal matter from the subject; and

measuring for expression of the reporter gene in the sample of fecal matter,

wherein detectable expression of the reporter gene indicates the presence of the target.

7. The method of claim 6 , wherein the target is an indicator of a condition in the gastrointestinal tract or colon.

8. The method of claim 7 , wherein the gastrointestinal tract or colon condition is selected from the group consisting of cancer, inflammation, pathogenic bacterial infection, inflammatory bowel disease (IBD), Crohn's disease, colitis, and diabetes.

9. The method of claim 6 further comprising selecting a subject for detecting.

10. The method of claim 6 , wherein the subject has or is at risk of developing a gastrointestinal tract or colon condition.

11. The method of claim 6 , wherein the target is selected from the group consisting of tetrathionate, reactive oxygen species, H2S, sdiA, bacteria enterotoxins, calprotectin and lactoferrin.

12. An engineered unicellular organism comprising a memory circuit comprising:

a. a memory element comprising sequences of two antagonistic transcription factors or gene regulatory factors, and a reporter gene,

wherein the factors are arranged in a genetic toggle switch configuration, and

wherein the reporter gene is arranged downstream and operably linked to one of the factors; and

b. an inducible gene regulatory factor trigger element comprising an inducible promoter and a duplicated copy of one of the transcription or gene regulatory factors in the memory element,

wherein duplicated copy of the transcription or gene regulatory factor is operably linked to an inducible promoter,

wherein the inducible promoter is responsive to a stimulus, and

wherein the memory circuit is integrated into the genome of the organism.

13. The engineered unicellular organism of claim 12 , wherein the memory circuit is maintained in the organism without antibiotic selection.

14. The engineered unicellular organism of claim 12 , wherein the memory circuit comprises antagonistic transcription factors.

15. The engineered unicellular organism of claim 12 , wherein the antagonistic transcription factors are cI and Cro.

16. The engineered unicellular organism of claim 12 , wherein the reporter gene is selected from the group consisting of β-galactosidase (LacZ), chloramphenicol acetyltransferase (CAT), neomycin phosphotransferase (G418), bacteria luciferase (LuxAB), a fluorescent protein (FP), alkaline phosphatase (PhoA), and p-glucuronidase (GUS).

17. The engineered unicellular organism of claim 12 , wherein the inducible promoter is responsive to an environmental marker selected from the group consisting of a small molecule, endogenous two-component systems and gene-regulatory networks.

18. The engineered unicellular organism of claim 17 , wherein the small molecule is tetracycline, tetrathionate, reactive oxygen species, or hydrogen sulfide gas (H 2 S).

19. The engineered unicellular organism of claim 12 , wherein the reporter gene comprises a genomic rearrangement detectable by polymerase chain reaction (PCR).

20. A formulation comprising engineered unicellular organism of claim 12 and a pharmaceutically acceptable ingredient or an enhancer or a polymer.