In vivo monitor oxidative burst induced by Cd2+ stress for the oilseed rape (Brassica napus L.) based on electrochemical microbiosensor

Electrochemical Profiling of Plants

The profiling, or fingerprinting, of distinct varieties of the Plantae kingdom is based on the bioactive ingredients, which are systematically segregated to perform their detailed analysis. The secondary products portray a pivotal role in defining the ecophysiology of distinct plant species. There is a crucial role of the profiling domain in understanding the various features, characteristics, and conditions related to plants. Advancements in variable technologies have contributed to the development of highly specific sensors for the non-invasive detection of molecules. Furthermore, many hyphenated techniques have led to the development of highly specific integrated systems that allow multiplexed detection, such as high-performance liquid chromatography, gas chromatography, etc., which are quite cumbersome and un-economical. In contrast, electrochemical sensors are a promising alternative which are capable of performing the precise recognition of compounds due to efficient signal transduction. However, due to a few bottlenecks in understanding the principles and non-redox features of minimal metabolites, the area has not been explored. This review article provides an insight to the electrochemical basis of plants in comparison with other traditional approaches and with necessary positive and negative outlooks. Studies consisting of the idea of merging the fields are limited; hence, relevant non-phytochemical reports are included for a better comparison of reports to broaden the scope of this work.

Reverse Iontophoretic Extraction of Metabolites from Living Plants and their Identification by Ion-chromatography Coupled to High Resolution Mass Spectrometry

INTRODUCTION

The identification and characterisation of cellular metabolites has now become an important strategy to obtain insight into functional plant biology. However, the extraction of metabolites for identification and analysis is challenging and, at the present time, usually requires destruction of the plant.

OBJECTIVE

To detect different plant metabolites in living plants with no pre-treatment using the combination of iontophoresis and ion-chromatography with mass spectrometry detection.

METHODOLOGY

In this work, the simple and non-destructive method of reverse iontophoresis has been used to extract in situ multiple plant metabolites from intact Ocimum basilicum leaves. Subsequently, the analysis of these metabolites has been performed with ion chromatography coupled directly to high resolution mass spectrometric detection (IC-MS).

RESULTS

The application of reverse iontophoresis to living plant samples has avoided the need for complex pre-treatments. With this approach, no less than 24 compounds, including organic acids and sugars as well as adenosine triphosphate (ATP) were successfully detected.

CONCLUSION

The research demonstrates that it is feasible to monitor, therefore, a number of important plant metabolites using a simple, relatively fast and non-destructive approach. Copyright © 2016 John Wiley & Sons, Ltd.

Reactive oxygen species: Reactions and detection from photosynthetic tissues

Reactive oxygen species (ROS) have long been recognized as compounds with dual roles. They cause cellular damage by reacting with biomolecules but they also function as agents of cellular signaling. Several different oxygen-containing compounds are classified as ROS because they react, at least with certain partners, more rapidly than ground-state molecular oxygen or because they are known to have biological effects. The present review describes the typical reactions of the most important ROS. The reactions are the basis for both the detection methods and for prediction of reactions between ROS and biomolecules. Chemical and physical methods used for detection, visualization and quantification of ROS from plants, algae and cyanobacteria will be reviewed. The main focus will be on photosynthetic tissues, and limitations of the methods will be discussed.

Electrochemical detection of extracellular hydrogen peroxide in Arabidopsis thaliana: a real-time marker of oxidative stress

An electrochemical approach to directly measure the dynamic process of H2 O2 release from cultures of Arabidopsis thaliana cells is reported. This approach is based on H2 O2 oxidation on a Pt electrode in conjunction with continuous measurement of sample pH. For [H2 O2 ] <1 mm, calibration plots were linear and the amperometric response of the electrode was maximum at pH 6. At higher concentrations ([H2 O2 ] >1 mm), the amperometric response can be described by Michaelian-type kinetics and a mathematical expression relating current intensity and pH was obtained to quantitatively determine H2 O2 concentration. At pH 5.5, the detection limit of the sensor was 3.1 µm (S/N = 3), with a response sensitivity of 0.16 Am(-1 ) cm(-2) and reproducibility was within 6.1% in the range 1-5 × 10(-3 ) m (n = 5). Cell suspensions under normal physiological conditions had a pH between 5.5-5.7 and H2 O2 concentrations in the range 7.0-20.5 µm (n = 5). The addition of exogenous H2 O2 , as well as other potential stress stimuli, was made to the cells and the change in H2 O2 concentration was monitored. This real-time quantitative H2 O2 analysis is a potential marker for the evaluation of oxidative stress in plant cell cultures.