Cancer cells use elevated glutathione (GSH) levels as an inner line of defense to evade apoptosis and develop drug resistance.Inthis study,wedescribe anovel 2,4-nitrobenzenesulfonyl (DNS) protected 2-hydroxyisophthalamide system that exploits GSH for its activation into free 2-hydroxyisophthalamide forming supramolecular M + /Cl À channels.Better permeation of the DNS protected compound into MCF-7 cells compared to the free 2-hydroxyisophthalamide and GSHactivatable ion transport resulted in higher cytotoxicity,w hich was associated with increased oxidative stress that further reduced the intracellular GSH levels and altered mitochondrial membrane permeability leading to the induction of the intrinsic apoptosis pathway.T he GSH-activatable transport-mediated cell death was further validated in rat insulinoma cells (INS-1E);w herein the intracellular GSH levels showed ad irect correlation to the resulting cytotoxicity.L astly,t he active compound was found to restrict the growth and proliferation of 3D spheroids of MCF-7 cells with efficiency similar to that of the anticancer drug doxorubicin.Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under https://doi.

Mycobacterium smegmatis, the saprophytic soil mycobacterium, is routinely used as a surrogate system to study the human pathogen Mycobacterium tuberculosis. It has also been reported as an opportunistic pathogen in immunocompromised hosts. In addition, it can exist in several ecological setups, thereby suggesting its capacity to adapt to a variety of environmental cues. In this study, we employed untargeted proton nuclear magnetic resonance ( 1 H-NMR)-based metabolomics to identify metabolites and metabolic pathways critical for early adaptive responses to acidic stress, oxidative stress, and nutrient starvation in Mycobacterium smegmatis. We identified 31, 20, and 46 metabolites that showed significant changes in levels in response to acidic, oxidative, and nutrient starvation stresses, respectively. Pathway analyses showed significant perturbations in purine-pyrimidine, amino-acid, nicotinate-nicotinamide, and energy metabolism pathways. Besides these, differential levels of intermediary metabolites involved in ␣-glucan biosynthesis pathway were observed. We also detected high levels of organic osmolytes, methylamine, and betaine during nutrient starvation and oxidative stress. Further, tracing the differential levels of these osmolytes through computational search tools, gene expression studies (using reverse transcription-PCR [RT-PCR]), and enzyme assays, we detected the presence of a putative pathway of biosynthesis of betaine, methylamine, and dimethylamine previously unreported in Mycobacterium smegmatis. IMPORTANCE Alterations in metabolite levels provide fast and direct means to regulate enzymatic reactions and, therefore, metabolic pathways. This study documents, for the first time, the metabolic changes that occur in Mycobacterium smegmatis as a response to three stresses, namely, acidic stress, oxidative stress, and nutrient starvation. These stresses are also faced by intracellular mycobacteria during infection and therefore may be extended to frame therapeutic interventions for pathogenic mycobacteria. In addition to the purine-pyrimidine, amino acid, nicotinate-nicotinamide, and energy metabolism pathways that were found to be affected in response to different stresses, a novel putative methylamine biosynthesis pathway was identified to be present in Mycobacterium smegmatis.

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Cold-induced sweetening (CIS) causes considerable losses to the potato processing industry wherein the selection of potato genotypes using biochemical information has found to be advantageous. Here, 1 H NMR spectroscopy was performed to identify metabolic perturbations from tubers of five potato cultivars (Atlantic, Frito Lay-1533, Kufri Jyoti, Kufri Pukhraj, and PU1) differing in their CIS ability and processing characteristics at harvest and after cold storage (4 °C). Thirty-nine water-soluble metabolites were detected wherein significantly affected metabolites after cold storage were categorized into sugars, sugar alcohols, amino acids, and organic acids. Multivariate statistical analysis indicated significant differences in the metabolic profiles among the potato cultivars. Pathway enrichment analysis revealed that carbohydrates, amino acids, and organic acids are the key players in CIS. Interestingly, one of the processing cultivars, FL-1533, exhibited a unique combination of metabolites represented by low levels of glucose, fructose, and asparagine accompanied by high citrate levels. Conversely, non-processing cultivars (Kufri Pukhraj and Kufri Jyoti) showed elevated glucose, fructose, and malate levels. Our results indicate that metabolites such as glucose, fructose, sucrose, asparagine, glutamine, citrate, malate, proline, 4-aminobutyrate can be potentially utilized for the prediction, selection, and development of potato cultivars for long-term storage, nutritional, as well as processing attributes. Potato (Solanum tuberosum L.)-an important staple non-grain vegetable food crop-is used globally for both processing and table purposes. In order to ensure the year-round supply of quality tubers for consumption, cold storage of potato tubers after harvesting is mandatory to reduce sprouting, prevent diseases, avoid losses due to shrinkage, and extend post-harvest shelf life 1,2. Usually 8-10 °C is the recommended storage temperature for potato tubers along with sprout suppressants, such as isopropyl N-(3-chlorophenyl) carbamate. The use of such chemical suppressants-due to their environmental safety and toxicity issues-are being replaced and reliance on storage of potatoes at colder temperatures even below 4 °C has been increased gradually 3-5. During cold storage, potato tubers undergo cold-induced sweetening (CIS), wherein rapid degradation of starch and sucrose hydrolysis leads to the accumulation of reducing sugars (RS)-such as glucose and fructose 6. During the frying process, these RS react with free amino acids in a Maillard reaction to generate dark-pigmented products that are bitter and unsightly to consumers. In addition to this, one of the products of the Maillard reaction is acrylamide-a potent neurotoxin and carcinogen 4,7. Hence, CIS is considered as one of the critical parameters in potato production as well as in processing; therefore, the identification and development of potato tubers

Cancer cells use elevated glutathione (GSH) levels as an inner line of defense to evade apoptosis and develop drug resistance. In this study, we describe a novel 2,4‐nitrobenzenesulfonyl (DNS) protected 2‐hydroxyisophthalamide system that exploits GSH for its activation into free 2‐hydroxyisophthalamide forming supramolecular M+/Cl− channels. Better permeation of the DNS protected compound into MCF‐7 cells compared to the free 2‐hydroxyisophthalamide and GSH‐activatable ion transport resulted in higher cytotoxicity, which was associated with increased oxidative stress that further reduced the intracellular GSH levels and altered mitochondrial membrane permeability leading to the induction of the intrinsic apoptosis pathway. The GSH‐activatable transport‐mediated cell death was further validated in rat insulinoma cells (INS‐1E); wherein the intracellular GSH levels showed a direct correlation to the resulting cytotoxicity. Lastly, the active compound was found to restrict the growth and proliferation of 3D spheroids of MCF‐7 cells with efficiency similar to that of the anticancer drug doxorubicin.