DYn-2 based identification of Arabidopsis sulfenomes

Identifying the sulfenylation state of stressed cells is emerging as a strategic approach for the detection of key reactive oxygen species signaling proteins. Here, we optimized an in vivo trapping method for cysteine sulfenic acids in hydrogen peroxide (H2O2) stressed plant cells using a dimedone based DYn-2 probe. We demonstrated that DYn-2 specifically detects sulfenylation events in an H2O2 dose- and time-dependent way. With mass spectrometry, we identified 226 sulfenylated proteins after H2O2 treatment of Arabidopsis cells, residing in the cytoplasm (123); plastid (68); mitochondria (14); nucleus (10); endoplasmic reticulum, Golgi and plasma membrane (7) and peroxisomes (4). Of these, 123 sulfenylated proteins have never been reported before to undergo cysteine oxidative post-translational modifications in plants. All in all, with this DYn-2 approach, we have identified new sulfenylated proteins, and gave a first glance on the locations of the sulfenomes of Arabidopsis thaliana

Climatic Impacts and Responses of Migratory and Non-Migratory Fishers of the Padma River, Bangladesh

This study empirically assesses the impacts of climatic events on the inland fishers (i.e., migratory and non-migratory) in Bangladesh and explores their responses to those events. Here, the migratory refers to the fishers who change their fishing location seasonally and voluntarily, whereas the non-migratory fishers fish in the same area. It is assumed that there exist differences in both the impacts of an event and the responses to the event between migratory and non-migratory fishers and therefore, a ‘difference triangle’ conceptual framework is developed and tested empirically under this research. Employing mix-method (qualitative and quantitative), a field study was conducted during July⁻October 2015 from the Padma River depended fishers. Identified climatic events under this study are: storms, changes in rainfall and temperature and riverbank erosion. The migratory and non-migratory fishers were affected quite similarly by storms and changes in rainfall and temperature. However, riverbank erosion affected only non-migratory fishers. Both the migratory and non-migratory fishers adopted different strategies to cope with different climatic events, like, they took shelter in safe places, sold productive assets, reduced food consumption, took credit from informal sources and employed their school-going children. As adaptation strategies, they modernized their fishing boats, intensified fishing, built embankments and diversified livelihoods. Unlike the impacts, considerable differences were found in their coping and adaptation strategies. Comparing to non-migratory fishers, a smaller number of migratory fishers sold their assets, took informal credit and intensified fishing and diversified their livelihoods. The result of this study indicates the significance of differences in the impacts of climatic events for the migratory and non-migratory fishers and therefore, this research has policy implication for the betterment of fishers’ community in general

Oxidative post-translational modifications of cysteine residues in plant signal transduction

In plants, fluctuation of the redox balance by altered levels of reactive oxygen species (ROS) can affect many aspects of cellular physiology. ROS homeostasis is governed by a diversified set of antioxidant systems. Perturbation of this homeostasis leads to transient or permanent changes in the redox status and is exploited by plants in different stress signalling mechanisms. Understanding how plants sense ROS and transduce these stimuli into downstream biological responses is still a major challenge. ROS can provoke reversible and irreversible modifications to proteins that act in diverse signalling pathways. These oxidative post-translational modifications (Ox-PTMs) lead to oxidative damage and/or trigger structural alterations in these target proteins. Characterization of the effect of individual Ox-PTMs on individual proteins is the key to a better understanding of how cells interpret the oxidative signals that arise from developmental cues and stress conditions. This review focuses on ROS-mediated Ox-PTMs on cysteine (Cys) residues. The Cys side chain, with its high nucleophilic capacity, appears to be the principle target of ROS. Ox-PTMs on Cys residues participate in various signalling cascades initiated by plant stress hormones. We review the mechanistic aspects and functional consequences of Cys Ox-PTMs on specific target proteins in view of stress signalling events

Cysteines under ROS attack in plants : a proteomics view

Plants generate reactive oxygen species (ROS) as part of their metabolism and in response to various external stress factors, potentially causing significant damage to biomolecules and cell structures. During the course of evolution, plants have adapted to ROS toxicity, and use ROS as signalling messengers that activate defence responses. Cysteine (Cys) residues in proteins are one of the most sensitive targets for ROS-mediated post-translational modifications, and they have become key residues for ROS signalling studies. The reactivity of Cys residues towards ROS, and their ability to react to different oxidation states, allow them to appear at the crossroads of highly dynamic oxidative events. As such, a redox-active cysteine can be present as S-glutathionylated (-SSG), disulfide bonded (S-S), sulfenylated (-SOH), sulfinylated (-SO2H), and sulfonylated (-SO3H). The sulfenic acid (-SOH) form has been considered as part of ROS-sensing pathways, as it leads to further modifications which affect protein structure and function. Redox proteomic studies are required to understand how and why cysteines undergo oxidative post-translational modifications and to identify the ROS-sensor proteins. Here, we update current knowledge of cysteine reactivity with ROS. Further, we give an overview of proteomic techniques that have been applied to identify different redox-modified cysteines in plants. There is a particular focus on the identification of sulfenylated proteins, which have the potential to be involved in plant signal transduction