Understanding the Mechanism of Formation of a Response to Juglone for Intact and Immobilized Bacterial Cells as Recognition Elements of Microbial Sensors: Processes Causing the Biosensor Response

Abstract

Microbial reactor sensors (based on freshly harvested intact microbial cells) or microbial membrane sensors (based on immobilized microbial cells) can be used as convenient instruments for studying processes that cause the response of a biosensor, such as the properties of enzymes or the characteristics of metabolism. However, the mechanisms of the formation of biosensors responses have not yet been fully understood to study only one of these processes. In this work, the results of studies on the formation of a response to juglone for intact and immobilized bacterial cells used as receptors are presented. It was shown that the contribution of reactive oxygen species (ROS) to the formation of the biosensor response depends on the culture receptor and the form of juglone, quinone, or phenolate used. The response to the quinone form of juglone both for intact and immobilized cells of catalase-positive actinobacterium is formed regardless of the presence of ROS. The response of freshly harvested intact actinobacterial cells was caused by the rate of the enzymatic conversion of juglone. The rate of the response of immobilized actinobacterial cells was influenced by the activity of transport systems and metabolism. The response of immobilized pseudomonad cells was caused by the transport of juglone into cells, the inhibitory effect of juglone-induced ROS, and juglone metabolism.

Ultrastable Bioderived Organic Anode Induced by Synergistic Coupling of Binder/Carbon-Network for Advanced Potassium-Ion Storage

“…However, when the hydroxyl group reacts with NaOH, the quinone form transforms into the negatively charged phenolate form, which makes the molecules water-soluble. 34 Subsequently, MWCNT was added into the solution of the phenolate form of juglone, followed by sonication to form a uniform suspension. Then, the slow dropwise addition of the mixture's suspension into an aqueous HCl solution allowed the phenolate form of juglone to precipitate and create a compound with MWCNT, resulting in the formation of the J@CNT nanohybrids.…”

“…The pristine organic small molecule juglone is insoluble in water. However, when the hydroxyl group reacts with NaOH, the quinone form transforms into the negatively charged phenolate form, which makes the molecules water-soluble . Subsequently, MWCNT was added into the solution of the phenolate form of juglone, followed by sonication to form a uniform suspension.…”

Engineering Antifouling Nanofiltration Membranes Using Amino-Quinone Networks–Phytic Acid Pseudo Zwitterionic Clusters for Water Treatment

“…The reaction degree of HNQ and PEI can be determined by measuring the absorbance of the HNQ/PEI mixtures using a UV–vis spectrophotometer (UV-1900, Shimadzu, Japan). Briefly, since HNQ is slightly soluble in water, a 1.0 mg mL –1 HNQ solution was prepared by dissolving a certain amount of HNQ in 10 mL of ethanol followed by diluting with 90 mL of Tris buffer solution (50 mM, pH 8.5). Then, the HNQ/PEI solution was prepared by adding a certain amount of PEI to achieve a desired HNQ/PEI ratio.…”

Microbial Biosensor for Characterization of a Microorganism: A Review focusing on the Biochemical Activity of Microbial Cells

“…The first case is when constitutive enzyme systems initiated processes, transport and metabolism. If cells of a culture-receptor were grown on a rich medium (substrate inducer-free medium ) and the response to a substrate was recorded using both the MMS and the RMS, then constitutive enzyme systems caused cells' response to substrate [11,21]. The second case is when inducible enzyme systems caused cells' response to substrate, i.e.…”