Anticandidal Activity of a Siderophore from Marine Endophyte <i>Pseudomonas aeruginosa</i> Mgrv7

An endophytic symbiont P. aeruginosa-producing anticandidal siderophore was recovered from mangrove leaves for the first time. Production was optimal in a succinate medium supplemented with 0.4% citric acid and 15 µM iron at pH 7 and 35 °C after 60 h of fermentation. UV spectra of the acidic preparation after purification with Amberlite XAD-4 resin gave a peak at 400 nm, while the neutralized form gave a peak at 360 nm. A prominent peak with RP-HPLC was obtained at RT 18.95 min, confirming its homogeneity. It was pH stable at 5.0–9.5 and thermally stable at elevated temperatures, which encourages the possibility of its application in extreme environments. The minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) against Candida spp. Were in the range of 128 µg/mL and lower. It enhanced the intracellular iron accumulation with 3.2–4.2-fold (as judged by atomic absorption spectrometry) with a subsequent increase in the intracellular antioxidative enzymes SOD and CAT. Furthermore, the malondialdehyde (MDA) concentration due to cellular lipid peroxidation increased to 3.8-fold and 7.3-fold in C. albicans and C. tropicalis, respectively. The scanning electron microscope (SEM) confirmed cellular damage in the form of roughness, malformation, and production of defensive exopolysaccharides and/or proteins after exposure to siderophore. In conclusion, this anticandidal siderophore may be a promising biocontrol, nonpolluting agent against waterborne pathogens and pathogens of the skin. It indirectly kills Candida spp. by ferroptosis and mediation of hyperaccumulation of iron rather than directly attacking the cell targets, which triggers the activation of antioxidative enzymes

Humic Substances: Determining Potential Molecular Regulatory Processes in Plants

Humic substances (HSs) have considerable effects on soil fertility and crop productivity owing to their unique physiochemical and biochemical properties, and play a vital role in establishing biotic and abiotic interactions within the plant rhizosphere. A comprehensive understanding of the mode of action and tissue distribution of HS is, however, required, as this knowledge could be useful for devising advanced rhizospheric management practices. These substances trigger various molecular processes in plant cells, and can strengthen the plant’s tolerance to various kinds of abiotic stresses. HS manifest their effects in cells through genetic, post-transcriptional, and post-translational modifications of signaling entities that trigger different molecular, biochemical, and physiological processes. Understanding of such fundamental mechanisms will provide a better perspective for defining the cues and signaling crosstalk of HS that mediate various metabolic and hormonal networks operating in plant systems. Various regulatory activities and distribution strategies of HS have been discussed in this review

Discovery of 1-(5-bromopyrazin-2-yl)-1-[3-(trifluoromethyl)benzyl]urea as a promising anticancer drug via synthesis, characterization, biological screening, and computational studies

Abstract Cancer and different types of tumors are still the most resistant diseases to available therapeutic agents. Finding a highly effective anticancer drug is the first target and concern of thousands of drug designers. In our attempts to address this concern, a new pyrazine derivative, 1-(5-bromopyrazin-2-yl)-1-[3-(trifluoromethyl)benzyl]urea (BPU), was designed via structural optimization and synthesized to investigate its anticancer/antitumor potential. The in-vitro anticancer properties of BPU were evaluated by MTT assay using selected cell lines, including the Jurkat, HeLa, and MCF-7 cells. The Jurkat cells were chosen to study the effect of BPU on cell cycle analysis using flow cytometry technique. BPU exhibited an effective cytotoxic ability in all the three cell lines assessed. It was found to be more prominent with the Jurkat cell line (IC50 = 4.64 ± 0.08 µM). When it was subjected to cell cycle analysis, this compound effectively arrested cell cycle progression in the sub-G1 phase. Upon evaluating the antiangiogenic potential of BPU via the in-vivo/ex-vivo shell-less chick chorioallantoic membrane (CAM) assays, the compound demonstrated very significant findings, revealing a complementary supportive action for the compound to act as a potent anticancer agent through inhibiting blood vessel formation in tumor tissues. Moreover, the docking energy of BPU computationally scored − 9.0 kcal/mol with the human matrix metalloproteinase 2 (MMP-2) and − 7.8 kcal/mol with the human matrix metalloproteinase 9 (MMP-9), denoting promising binding results as compared to the existing drugs for cancer therapy. The molecular dynamics (MD) simulation outcomes showed that BPU could effectively bind to the previously-proposed catalytic sites of both MMP-2 and MMP-9 enzymes with relatively stable statuses and good inhibitory binding abilities and parameters. Our findings suggest that the compound BPU could be a promising anticancer agent since it effectively inhibited cell proliferation and can be selected for further in-vitro and in-vivo investigations. In addition, the current results can be extensively validated by conducting wet-lab analysis so as to develop novel and better derivatives of BPU for cancer therapy with much less side effects and higher activities