
@article {128069,
	title = {Unusual Relationship between Iron Deprivation and Organophosphate Hydrolase Expression.},
	journal = {Appl Environ Microbiol},
	year = {2023},
	month = {2023 Apr 19},
	pages = {e0190322},
	abstract = {<p>Organophosphate hydrolases (OPH), hitherto known to hydrolyze the third ester bond of organophosphate (OP) insecticides and nerve agents, have recently been shown to interact with outer membrane transport components, namely, TonB and ExbB/ExbD. In an OPH negative background, Sphingopyxis wildii cells failed to transport ferric enterobactin and showed retarded growth under iron-limiting conditions. We now show the OPH-encoding organophosphate degradation () gene from Sphingobium fuliginis ATCC 27551 to be part of the iron regulon. A -box motif found to be overlapping with the transcription start site (TSS) of the gene coordinates with an iron responsive element (IRE) RNA motif identified in the 5{\textquoteright} coding region of the mRNA to tightly regulate gene expression. The -box motif serves as a target for the Fur repressor in the presence of iron. A decrease in iron concentration leads to the derepression of . IRE RNA inhibits the translation of mRNA and serves as a target for apo-aconitase (IRP). The IRP recruited by the IRE RNA abrogates IRE-mediated translational inhibition. Our findings establish a novel, multilayered, iron-responsive regulation that is crucial for OPH function in the transport of siderophore-mediated iron uptake. Sphingobium fuliginis, a soil-dwelling microbe isolated from agricultural soils, was shown to degrade a variety of insecticides and pesticides. These synthetic chemicals function as potent neurotoxins, and they belong to a class of chemicals termed organophosphates. codes for OPH, an enzyme that has been shown to be involved in the metabolism of several organophosphates and their derivatives. Interestingly, OPH has also been shown to facilitate siderophore-mediated iron uptake in and in another Sphingomonad, namely, , implying that this organophosphate-metabolizing protein has a role in iron homeostasis, as well. Our research dissects the underlying molecular mechanisms linking iron to the expression of OPH, prompting a reconsideration of the role of OPH in Sphingomonads and a reevaluation of the evolutionary origins of the OPH proteins from soil bacteria.</p>
},
	issn = {1098-5336},
	doi = {10.1128/aem.01903-22},
	author = {Nandavaram, Aparna and Nandakumar, Anirudh and Kashif, G M and Sagar, Annapoorni Lakshman and Shailaja, G and Ramesh, Arati and Siddavattam, Dayananda}
}
@article {100194,
	title = {Engineered RNA biosensors enable ultrasensitive SARS-CoV-2 detection in a simple color and luminescence assay.},
	journal = {Life Sci Alliance},
	volume = {4},
	year = {2021},
	month = {2021 Dec},
	abstract = {<p>The continued resurgence of the COVID-19 pandemic with multiple variants underlines the need for diagnostics that are adaptable to the virus. We have developed toehold RNA-based sensors across the SARS-CoV-2 genome for direct and ultrasensitive detection of the virus and its prominent variants. Here, isothermal amplification of a fragment of SARS-CoV-2 RNA coupled with activation of our biosensors leads to a conformational switch in the sensor. This leads to translation of a reporter protein, for example, LacZ or nano-lantern that is easily detected using color/luminescence. By optimizing RNA amplification and biosensor design, we have generated a highly sensitive diagnostic assay that is capable of detecting as low as 100 copies of viral RNA with development of bright color. This is easily visualized by the human eye and quantifiable using spectrophotometry. Finally, this PHAsed NASBA-Translation Optical Method (PHANTOM) using our engineered RNA biosensors efficiently detects viral RNA in patient samples. This work presents a powerful and universally accessible strategy for detecting COVID-19 and variants. This strategy is adaptable to further viral evolution and brings RNA bioengineering center-stage.</p>
},
	issn = {2575-1077},
	doi = {10.26508/lsa.202101213},
	author = {Chakravarthy, Anirudh and Nandakumar, Anirudh and George, Geen and Ranganathan, Shyamsundar and Umashankar, Suchitta and Shettigar, Nishan and Palakodeti, Dasaradhi and Gulyani, Akash and Ramesh, Arati}
}
