To remember, or not to remember? Potential impact of memory modification on narrative identity, personal agency, mental health, and well-being.

Memory modification technologies (MMTs)-interventions within the memory affecting its functions and contents in specific ways-raise great therapeutic hopes but also great fears. Ethicists have expressed concerns that developing and using MMTs may endanger the very fabric of who we are-our personal identity. This threat has been mainly considered in relation to two interrelated concerns: truthfulness and narrative self-constitution. In this article, we propose that although this perspective brings up important matters concerning the potential aftermaths of MMT utilization, it fails to tell the whole story. We suggest that capturing more tangible potential consequences of MMT use, namely, its psychological ramifications is crucial both in ethical considerations and in making decisions regarding the permissibility of such interventions. To this end, we first examine what current MMTs are capable of and what are the prospects of emerging MMTs. Subsequently, we outline the relationship between memory and personal identity; specifically, we indicate that concepts of self-defining memories and narrative identity are crucial to considering how MMTs may influence one's psychological functioning. On this basis, we analyze potential consequences of narrative disruption that may be the result of the use of MMTs; more precisely, we consider its potential effects on mental health, well-being, and personal agency, and outline the ethical dilemmas that decision-makers face in this context. We conclude by considering the broader cultural context that may have influence on policymaking regarding permissibility of memory modification interventions.

Quantification of thiols and disulfides.

BACKGROUND: Disulfide bond formation is a key posttranslational modification, with implications for structure, function and stability of numerous proteins. While disulfide bond formation is a necessary and essential process for many proteins, it is deleterious and disruptive for others. Cells go to great lengths to regulate thiol-disulfide bond homeostasis, typically with several, apparently redundant, systems working in parallel. Dissecting the extent of oxidation and reduction of disulfides is an ongoing challenge due, in part, to the facility of thiol/disulfide exchange reactions. SCOPE OF REVIEW: In the present account, we briefly survey the toolbox available to the experimentalist for the chemical determination of thiols and disulfides. We have chosen to focus on the key chemical aspects of current methodology, together with identifying potential difficulties inherent in their experimental implementation. MAJOR CONCLUSIONS: While many reagents have been described for the measurement and manipulation of the redox status of thiols and disulfides, a number of these methods remain underutilized. The ability to effectively quantify changes in redox conditions in living cells presents a continuing challenge. GENERAL SIGNIFICANCE: Many unresolved questions in the metabolic interconversion of thiols and disulfides remain. For example, while pool sizes of redox pairs and their intracellular distribution are being uncovered, very little is known about the flux in thiol-disulfide exchange pathways. New tools are needed to address this important aspect of cellular metabolism. This article is part of a Special Issue entitled Current methods to study reactive oxygen species - pros and cons and biophysics of membrane proteins. Guest Editor: Christine Winterbourn.

Mass spectrometry-based identification of S-nitrosocysteine in vivo using organic mercury assisted enrichment.

Protein S-nitrosylation is considered as one of the molecular mechanisms by which nitric oxide regulates signaling events and protein function. The present review presents an updated method which allows for the site-specific detection of S-nitrosylated proteins in vivo. The method is based on enrichment of S-nitrosylated proteins or peptides using organomercury compounds followed by LC-MS/MS detection. Technical aspects for determining the reaction and binding efficiency of the mercury resin that assists enrichment of S-nitrosylated proteins are presented and discussed. In addition, emphasis is given to the specificity of the method by providing technical details for the generation of four chemically distinct negative controls. Finally it is provided an overview of the key steps for generation and evaluation of mass spectrometry derived data.

S-sulfhydration/desulfhydration and S-nitrosylation/denitrosylation: a common paradigm for gasotransmitter signaling by H2S and NO.

Sulfhydryl groups on protein Cys residues undergo an array of oxidative reactions and modifications, giving rise to a virtual redox zip code with physiological and pathophysiological relevance for modulation of protein structure and functions. While over two decades of studies have established NO-dependent S-nitrosylation as ubiquitous and fundamental for the regulation of diverse protein activities, proteomic methods for studying H2S-dependent S-sulfhydration have only recently been described and now suggest that this is also an abundant modification with potential for global physiological importance. Notably, protein S-sulfhydration and S-nitrosylation bear striking similarities in terms of their chemical and biological determinants, as well as reversal of these modifications via group-transfer to glutathione, followed by the removal from glutathione by enzymes that have apparently evolved to selectively catalyze denitrosylation and desulfhydration. Here we review determinants of protein and low-molecular-weight thiol S-sulfhydration/desulfhydration, similarities with S-nitrosylation/denitrosylation, and methods that are being employed to investigate and quantify these gasotransmitter-mediated cell signaling systems.

Functional proteomics approaches for the identification of transnitrosylase and denitrosylase targets.

Protein S-nitrosylation is a dynamic post-translational modification (PTM) of specific cysteines within a target protein. Both proteins and small molecules are known to regulate the attachment and removal of this PTM, and proteins exhibiting such a function are transnitrosylase or denitrosylase candidates. With the advent of the biotin switch technique coupled to high-throughput proteomics workflows, the identification and quantification of large numbers of S-nitrosylated proteins and peptides is now possible. Proper analysis and interpretation of high throughout and quantitative proteomics data will help identify specific transnitrosylase and denitrosylase target peptide sequences and contribute to an understanding of the function and regulation of specific S-nitrosylation events. Here we describe the application of a quantitative proteomics approach using isotope-coded affinity tags (ICAT) in the biotin switch approach for the identification of transnitrosylation and denitrosylation targets of thioredoxin 1, an enigmatic protein with both reported transnitrosylase and denitrosylase activities.

Proteomic profiling of a mouse model of acute intestinal Apc deletion leads to identification of potential novel biomarkers of human colorectal cancer (CRC).

Colorectal cancer (CRC) is the fourth most common cause of cancer-related death worldwide. Accurate non-invasive screening for CRC would greatly enhance a population's health. Adenomatous polyposis coli (Apc) gene mutations commonly occur in human colorectal adenomas and carcinomas, leading to Wnt signalling pathway activation. Acute conditional transgenic deletion of Apc in murine intestinal epithelium (AhCre(+)Apc(fl)(/)(fl)) causes phenotypic changes similar to those found during colorectal tumourigenesis. This study comprised a proteomic analysis of murine small intestinal epithelial cells following acute Apc deletion to identify proteins that show altered expression during human colorectal carcinogenesis, thus identifying proteins that may prove clinically useful as blood/serum biomarkers of colorectal neoplasia. Eighty-one proteins showed significantly increased expression following iTRAQ analysis, and validation of nine of these by Ingenuity Pathaway Analysis showed they could be detected in blood or serum. Expression was assessed in AhCre(+)Apc(fl)(/)(fl) small intestinal epithelium by immunohistochemistry, western blot and quantitative real-time PCR; increased nucelolin concentrations were also detected in the serum of AhCre(+)Apc(fl)(/)(fl) and Apc(Min)(/)(+) mice by ELISA. Six proteins; heat shock 60kDa protein 1, Nucleolin, Prohibitin, Cytokeratin 18, Ribosomal protein L6 and DEAD (Asp-Glu-Ala-Asp) box polypeptide 5,were selected for further investigation. Increased expression of 4 of these was confirmed in human CRC by qPCR. In conclusion, several novel candidate biomarkers have been identified from analysis of transgenic mice in which the Apc gene was deleted in the intestinal epithelium that also showed increased expression in human CRC. Some of these warrant further investigation as potential serum-based biomarkers of human CRC.

Latest Performance Improvement Strategies and Techniques Used in 5G Antenna Designing Technology, a Comprehensive Study.

In the recent era, fifth-generation technology (5G) has not been fully implemented in the realm of wireless communication. To have excellent accessible bandwidth feasibility, and in order to achieve the aims of 5G standards, such as higher data rates and ultrahigh-definition video streaming, the millimeter wave (mmWave) band must be employed. Services with minimal latency and many other features are feasible only in the mmWave spectrum. To avoid numerous communication complexities such as high connection losses, short wavelength, and restricted bandwidth, as well as path-loss challenges in the mmWave range, an antenna with wide bandwidth, high gain, narrow steerable beam, high isolation, low side-lobe levels, and multiband features is required to alleviate these difficulties and meet 5G communication standards. To overcome these challenges, specific strategies and techniques should be employed in the traditional antenna designing procedure to excellently improve the performance of the antenna in terms of bandwidth, gain, and efficiency and to reduce the mutual coupling effect between the closely colocated antenna elements in MIMOs and arrays. The researchers reported on a variety of bandwidth and gain improvement approaches. To gain broader coverage, traditional antenna design techniques must be modified. In this study, the latest state-of-the-art work is reviewed, such as the role of the metamaterials (MMTs), parasitic patches, hybrid feeding, EBG structure, impact of the slots with different geometrical shapes in the radiator to achieve the goal of wide bandwidth, boosted gain, reduced side-lobes level, as well as stable radiation properties. Mutual coupling reduction techniques are also briefly reported. The role of reconfigurability is focused on in this study, and at the end, the future challenges in the field of antenna design and possible remedies to such issues are reviewed.

Personality and Authenticity in Light of the Memory-Modifying Potential of Optogenetics.

There has been a growing interest in research concerning memory modification technologies (MMTs) in recent years. Neuroscientists and psychologists are beginning to explore the prospect of controllable and intentional modification of human memory. One of the technologies with the greatest potential to this end is optogenetics-an invasive neuromodulation technique involving the use of light to control the activity of individual brain cells. It has recently shown the potential to modify specific long-term memories in animal models in ways not yet possible with other MMTs. As the therapeutic potential of optogenetics has already prompted approval of the first human trials, it is especially important and timely to consider the opportunities and dangers this technology may entail. In this article, we focus on possible consequences of optogenetics as an MMT by analyzing fundamental threats potentially associated with memory modifications: the potential disruption of personality and authenticity.

S-methyl Methanethiosulfonate: Promising Late Blight Inhibitor or Broad Range Toxin?

(1) Background: S-methyl methanethiosulfonate (MMTS), a sulfur containing volatile organic compound produced by plants and bacterial species, has recently been described to be an efficient anti-oomycete agent with promising perspectives for the control of the devastating potato late blight disease caused by Phytophthora infestans. However, earlier work raised questions regarding the putative toxicity of this compound. To assess the suitability of MMTS for late blight control in the field, the present study thus aimed at evaluating the effect of MMTS on a wide range of non-target organisms in comparison to P. infestans. (2) Methods: To this end, we exposed P. infestans, as well as different pathogenic and non-pathogenic fungi, bacteria, the nematode Caenorhabditis elegans as well as the plant Arabidopsis thaliana to MMTS treatment and evaluated their response by means of in vitro assays. (3) Results: Our results showed that fungi (both mycelium and spores) tolerated MMTS better than the oomycete P. infestans, but that the compound nevertheless exhibited non-negligible toxic effects on bacteria, nematodes and plants. (4) Conclusions: We discuss the mode of action of MMTS and conclude that even though this compound might be too toxic for chemical application in the field, its strong anti-oomycete activity could still be exploited when naturally released at the site of infection by plant-associated microbes inoculated as biocontrol agents.

Cruzain structures: apocruzain and cruzain bound to S-methyl thiomethanesulfonate and implications for drug design.

Chagas disease, which is caused by Trypanosoma cruzi, affects more than six million people worldwide. Cruzain is the major cysteine protease involved in the survival of this parasite. Here, the expression, purification and crystallization of this enzyme are reported. The cruzain crystals diffracted to 1.2 Šresolution, yielding two novel cruzain structures: apocruzain and cruzain bound to the reversible covalent inhibitor S-methyl thiomethanesulfonate. Mass-spectrometric experiments confirmed the presence of a methylthiol group attached to the catalytic cysteine. Comparison of these structures with previously published structures indicates the rigidity of the cruzain structure. These results provide further structural information about the enzyme and may help in new in silico studies to identify or optimize novel prototypes of cruzain inhibitors.

Camptothecin promotes the production of nitric oxide that triggers subsequent S-nitrosoproteome-mediated signaling cascades in endothelial cells.

Camptothecin (CPT) has been used for colorectal cancer therapy. At low concentration of 10-9M, CPT modulates endothelial nitric oxide production following the phosphorylation of LKB1 Ser431, AMPK-α Thr172, eNOS Ser633 and Ser1177. Elevated nitric oxide (NO) was observed by FA-OMe fluorescent probe. 726 S-nitrosoproteins were identified by iTRAQ quantitative proteomics. IPA analysis indicated that ERK/MAPK was closely linked in the signaling network. Further studies showed that CPT phosphorylated p38 MAPK Thr180/Tyr182 and dephosphorylated Tau Ser199/202. CPT also suppressed the TNF-α-induced expression of the inflammasome and cyclooxygenase 2. All this suggests that in addition to the original character of CPT in attenuating the binding of topoisomerase I and DNA in cancer cells, the role of CPT in triggering NO production and the subsequent S-nitrosylated signaling including anti-inflammatory effects in endothelial cells are proposed here. CPT, therefore, provides a potential application addition in preventing vascular disorders.

Identification of endogenously S-nitrosylated proteins in Arabidopsis plantlets: effect of cold stress on cysteine nitrosylation level.

S-nitrosylation is a nitric oxide (NO)-based post-translational modification regulating protein function and signalling. We used a combination between the biotin switch method and labelling with isotope-coded affinity tag to identify endogenously S-nitrosylated peptides in Arabidopsis thaliana proteins extracted from plantlets. The relative level of S-nitrosylation in the identified peptides was compared between unstressed and cold-stress seedlings. We thereby detected 62 endogenously nitrosylated peptides out of which 20 are over-nitrosylated following cold exposure. Taken together these data provide a new repertoire of endogenously S-nitrosylated proteins in Arabidopsis with cysteine S-nitrosylation site. Furthermore they highlight the quantitative modification of the S-nitrosylation status of specific cysteine following cold stress.

Specific cleavage of the lung surfactant protein A by human cathepsin S may impair its antibacterial properties.

Human cysteine cathepsins (Cats) are implicated in lung injuries and tissue remodeling and have recently emerged as important players in pulmonary inflammations. The proteolytic activities of Cat B, L, K, S and H are dramatically increased in the sputum of patients with cystic fibrosis (CF), suggesting a possible involvement in the CF pathophysiology. We found that pulmonary surfactant protein A (SP-A) that participates to innate host defense is extensively degraded in CF expectorations. Breakdown of SP-A was markedly decreased in CF sputum by E-64 and Mu-Leu-Hph-VSPh, a Cat S inhibitor. Cat S cleaved efficiently and specifically SP-A within critical residues of the solvent-exposed loop of its carbohydrate recognition (C-type lectin) domain that allows binding to pathogens. Cat S decreased aggregation properties of SP-A (self-aggregation, aggregation of phospholipid vesicles and rough LPS). Moreover cleavage of SP-A by Cat S reduced binding to yeast mannan and impaired agglutination of Escherichia coli and Pseudomonas aeruginosa, a foremost detrimental pathogen colonizing the lungs of CF patients. Besides human neutrophil serine proteases and bacterial proteases, we propose that Cat S may participate in the pathophysiology of CF by weakening the antibacterial activity of SP-A. More broadly, present results provide further indication that Cat S, along with Cats B and L, could display immuno-modulatory functions by inactivating key proteins involved in the innate immunity defense.