Publications by authors named "Mohamed El-Naggar"

89 Publications

New Amino Acid Schiff Bases as Anticancer Agents via Potential Mitochondrial Complex I-Associated Hexokinase Inhibition and Targeting AMP-Protein Kinases/mTOR Signaling Pathway.

Molecules 2021 Sep 2;26(17). Epub 2021 Sep 2.

Biochemistry Division, Chemistry Department, Faculty of Science, Tanta University, Tanta 31527, Egypt.

Two series of novel amino acid Schiff base ligands containing heterocyclic moieties, such as quinazolinone - and indole - were successfully synthesized and confirmed by spectroscopic techniques and elemental analysis. Furthermore, all compounds were investigated in silico for their ability to inhibit mitochondrial NADH: ubiquinone oxidoreductase (complex I) by targeting the AMPK/mTOR signaling pathway and inhibiting hexokinase, a key glycolytic enzyme to prevent the Warburg effect in cancer cells. This inhibitory pathway may be an effective strategy to cause cancer cell death due to an insufficient amount of ATP. Our results revealed that, out of 18 compounds, two ( and ) were top-ranked as they exhibited the highest binding energies of -8.8, -13.0, -7.9, and -10.0 kcal/mol in the docking analysis, so they were then selected for in vitro assessment. Compound promoted the best cytotoxic effect on MCF-7 with IC = 64.05 ± 0.14 μg/mL (0.135 mM) while compound exhibited the best cytotoxic effect on MDA-231 with IC = 46.29 ± 0.09 μg/mL (0.166 mM) Compounds and showed significant activation of AMPK protein and oxidative stress, which led to elevated expression of p53 and Bax, reduced Bcl-2 expression, and caused cell cycle arrest at the sub-G/G phase. Moreover, compounds and showed significant inhibition of the mTOR protein, which led to the activation of aerobic glycolysis for survival. This alternative pathway was also blocked as compounds and showed significant inhibitory effects on the hexokinase enzyme. These findings demonstrate that compounds and obeyed Lipinski's rule of five and could be used as privileged scaffolds for cancer therapy via their potential inhibition of mitochondrial complex I-associated hexokinase.
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http://dx.doi.org/10.3390/molecules26175332DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8434356PMC
September 2021

Engineering Biological Electron Transfer and Redox Pathways for Nanoparticle Synthesis.

Bioelectricity 2021 Jun 16;3(2):126-135. Epub 2021 Jun 16.

Department of Physics and Astronomy, University of Southern California, Los Angeles, California, USA.

Many species of bacteria are naturally capable of types of electron transport not observed in eukaryotic cells. Some species live in environments containing heavy metals not typically encountered by cells of multicellular organisms, such as arsenic, cadmium, and mercury, leading to the evolution of enzymes to deal with these environmental toxins. Bacteria also inhabit a variety of extreme environments, and are capable of respiration even in the absence of oxygen as a terminal electron acceptor. Over the years, several of these exotic redox and electron transport pathways have been discovered and characterized in molecular-level detail, and more recently synthetic biology has begun to utilize these pathways to engineer cells capable of detecting and processing a variety of metals and semimetals. One such application is the biologically controlled synthesis of nanoparticles. This review will introduce the basic concepts of bacterial metal reduction, summarize recent work in engineering bacteria for nanoparticle production, and highlight the most cutting-edge work in the characterization and application of bacterial electron transport pathways.
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http://dx.doi.org/10.1089/bioe.2021.0010DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8380940PMC
June 2021

Gastrodermis ultrastructure of the different life stages of the polyopisthocotylean monogenean gill parasite Discocotyle sagittata.

Parasitol Res 2021 Sep 18;120(9):3181-3193. Epub 2021 Aug 18.

Zoology Department, Faculty of Science, Mansoura University, Mansoura, Egypt.

The polyopisthocotylean Discocotyle sagittata is a blood-feeding monogenean that infects the gill lamellae of rainbow trout, Oncorhynchus mykiss, and brown trout, Salmo trutta. The ultrastructure of their alimentary tract, at different stages of the life cycle, was previously unknown. Here, we show that the gastrodermis of the oncomiracidium, subadult, and adult D. sagittata follows the same structural organization as that of other blood-feeding polyopisthocotyleans, being composed of digestive cells alternating with a connecting syncytium. Digestive cells of the oncomiracidium are found in three developmental forms: undifferentiated, developing differentiated, and differentiated (presumably functioning) cells whereas those of adult and subadult are present in a single functioning state with variable size and content. The apical cytoplasm of adult digestive cells forms conical outgrowths, a feature which is absent in the oncomiracidium. The connecting syncytium of the oncomiracidium has no evidence of metabolic activity, while that of adult and subadult is metabolically active. The lamellae of the connecting syncytium of adults and subadults are more numerous and larger, and their terminal portions are expanded, compared with those of the oncomiracidium. Parallel, tubular, membranous structures are characteristic of the apical cytoplasm of the connecting syncytium of the oncomiracidium. Luminal lamella in the oncomiracidium, subadult, and adult form balloon-like structures enclosing some luminal contents, but those of the oncomiracidium are larger, bounded by nucleated cytoplasmic layer, and enclose more luminal contents. The possible functions of these structures and mechanism of digestion in both oncomiracidium and adult are discussed.
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http://dx.doi.org/10.1007/s00436-021-07286-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8397695PMC
September 2021

Adverse effect of rheumatoid arthritis on male Wistar rat's fertility: protective role of Costus extract.

Environ Sci Pollut Res Int 2021 Aug 17. Epub 2021 Aug 17.

Zoology Department, Faculty of Sciences, Suez Canal University, Ismailia, 41522, Egypt.

Rheumatoid arthritis (RA) is a systemic autoimmune complaint. Advanced treatments resort to the traditional herbal therapy. The aim of this study is to assess the protective effect of Costus extract on the fertility of male rats with Freund's adjuvant-induced rheumatoid arthritis. Thirty male adult Wistar rats (190-200 g) were divided into six groups. They were subdivided into three groups; group I was the control group that received distilled water, and groups II and III received two various doses of Costus extract (200 and 400 mg/kg, respectively) for 60 days. Another three groups were subjected to RA induction via Freund's adjuvant. Rats were injected a dose of 0.1 ml of Freund's complete adjuvant (FCA) in the planter area of the left hind paw and then subdivided into 3 groups. Group I of RA-induced rats were given distilled water. The other two groups were given orally (200 and 400 mg/kg dosage of extract, respectively) from the 2nd day of RA induction for 60 days. Sex organ relative weight, sperm concentration assay, testicular histopathology and immunohistochemistry of androgen receptors, TNF α, and BAX protein were determined. The results showed that RA caused a significant decrease in the relative weight of sex organs and sperm count, which were relatively improved by doses of Costus (200, 400 mg/kg). RA induction caused testicular degeneration which markedly enhanced with Costus treatment as shown in histopathological sections. RA caused a reduction in %IHC of androgen receptors and increased expression level of both TNF α and BAX protein. Using IHC, it was revealed that RA caused a reduction in the expression level of androgen receptors and an increase in the expression of both TNF α and BAX protein. We can conclude that Costus speciosus had a potentially valuable role in improving fertility disorders caused by RA.
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http://dx.doi.org/10.1007/s11356-021-16001-yDOI Listing
August 2021

Eco-Friendly Synthesis, Biological Evaluation, and Molecular Docking Approach of Some New Quinoline Derivatives as Potential Antioxidant and Antibacterial Agents.

Front Chem 2021 10;9:679967. Epub 2021 Jun 10.

Chemistry Department, Faculty of Science, South Valley University, Qena, Egypt.

A new series of quinoline derivatives were efficiently synthesized one-pot multicomponent reaction (MCR) of resorcinol, aromatic aldehydes, β-ketoesters, and aliphatic/aromatic amines under solvent-free conditions. All products were obtained in excellent yields, pure at low-cost processing, and short time. The structures of all compounds were characterized by means of spectral and elemental analyses. In addition, all the synthesized compounds were screened for their antioxidant and antibacterial activity. Moreover, molecular docking studies of the new quinoline derivatives with the target enzymes, human NAD (P)H dehydrogenase (quinone 1) and DNA gyrase, were achieved to endorse their binding affinities and to understand ligand-enzyme possible intermolecular interactions. Compound displayed promising antioxidant and antibacterial activity, as well as it was found to have the highest negative binding energy of -9.1 and -9.3 kcal/mol for human NAD (P)H dehydrogenase (quinone 1) and DNA gyrase, respectively. Further, it complied with the Lipinski's rule of five, Veber, and Ghose. Therefore, the quinoline analogue could be promising chemical scaffold for the development of future drug candidates as antioxidant and antibacterial agents.
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http://dx.doi.org/10.3389/fchem.2021.679967DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8222571PMC
June 2021

Carbonate-hosted microbial communities are prolific and pervasive methane oxidizers at geologically diverse marine methane seep sites.

Proc Natl Acad Sci U S A 2021 Jun;118(25)

Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138;

At marine methane seeps, vast quantities of methane move through the shallow subseafloor, where it is largely consumed by microbial communities. This process plays an important role in global methane dynamics, but we have yet to identify all of the methane sinks in the deep sea. Here, we conducted a continental-scale survey of seven geologically diverse seafloor seeps and found that carbonate rocks from all sites host methane-oxidizing microbial communities with substantial methanotrophic potential. In laboratory-based mesocosm incubations, chimney-like carbonates from the newly described Point Dume seep off the coast of Southern California exhibited the highest rates of anaerobic methane oxidation measured to date. After a thorough analysis of physicochemical, electrical, and biological factors, we attribute this substantial metabolic activity largely to higher cell density, mineral composition, kinetic parameters including an elevated V, and the presence of specific microbial lineages. Our data also suggest that other features, such as electrical conductance, rock particle size, and microbial community alpha diversity, may influence a sample's methanotrophic potential, but these factors did not demonstrate clear patterns with respect to methane oxidation rates. Based on the apparent pervasiveness within seep carbonates of microbial communities capable of performing anaerobic oxidation of methane, as well as the frequent occurrence of carbonates at seeps, we suggest that rock-hosted methanotrophy may be an important contributor to marine methane consumption.
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http://dx.doi.org/10.1073/pnas.2006857118DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8237665PMC
June 2021

Synthesis, Molecular Docking Studies and In Silico ADMET Screening of New Heterocycles Linked Thiazole Conjugates as Potent Anti-Hepatic Cancer Agents.

Molecules 2021 Mar 18;26(6). Epub 2021 Mar 18.

Chemistry Department, Faculty of Science, South Valley University, Qena 83523, Egypt.

Thiazoles are important scaffolds in organic chemistry. Biosynthesis of thiazoles is considered to be an excellent target for the design of novel classes of therapeutic agents. In this study, a new series of 2-ethylidenehydrazono-5-arylazothiazoles - and 2-ethylidenehydrazono-5-arylazo- thiazolones - were synthesized via the cyclocondensation reaction of the appropriate hydrazonyl halides - and - with ethylidene thiosemicarbazide , respectively. Furthermore, the thiosemicarbazide derivative was reacted with different bromoacetyl compounds - to afford the respective thiazole derivatives -. Chemical composition of the novel derivatives was established on bases of their spectral data (FTIR, H-NMR, C-NMR and mass spectrometry) and microanalytical data. The newly synthesized derivatives were screened for their in vitro anti-hepatic cancer potency using an MTT assay. Moreover, an in silico technique was used to assess the interaction modes of the compounds with the active site of Rho6 protein. The docking studies of the target Rho6 with the newly synthesized fourteen compounds showed good docking scores with acceptable binding interactions. The presented results revealed that the newly synthesized compounds exhibited promising inhibition activity against hepatic cancer cell lines (HepG2).
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http://dx.doi.org/10.3390/molecules26061705DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8003218PMC
March 2021

Thiazole-Based Thiosemicarbazones: Synthesis, Cytotoxicity Evaluation and Molecular Docking Study.

Drug Des Devel Ther 2021 17;15:659-677. Epub 2021 Feb 17.

Chemistry Department, Faculty of Science, University of Cairo, Giza, Egypt.

Introduction: Hybrid drug design has developed as a prime method for the development of novel anticancer therapies that can theoretically solve much of the pharmacokinetic disadvantages of traditional anticancer drugs. Thus a number of studies have indicated that thiazole-thiophene hybrids and their bis derivatives have important anticancer activity. Mammalian Rab7b protein is a member of the Rab GTPase protein family that controls the trafficking from endosomes to the TGN. Alteration in the Rab7b expression is implicated in differentiation of malignant cells, causing cancer.

Methods: 1-(4-Methyl-2-(2-(1-(thiophen-2-yl) ethylidene) hydrazinyl) thiazol-5-yl) ethanone was used as building block for synthesis of novel series of 5-(1-(2-(thiazol-2-yl) hydrazono) ethyl) thiazole derivatives. The bioactivities of the synthesized compounds were evaluated with respect to their antitumor activities against MCF-7 tumor cells using MTT assay. Computer-aided docking protocol was performed to study the possible molecular interactions between the newly synthetic thiazole compounds and the active binding site of the target protein Rab7b. Moreover, the in silico prediction of adsorption, distribution, metabolism, excretion (ADME) and toxicity (T) properties of synthesized compounds were carried out using admetSAR tool.

Results: The results obtained showed that derivatives and have promising activity (IC = 14.6 ± 0.8 and 28.3 ± 1.5 µM, respectively) compared to Cisplatin (IC = 13.6 ± 0.9 µM). The molecular docking analysis reveals that the synthesized compounds are predicted to be fit into the binding site of the target Rab7b. In summary, the synthetic thiazole compounds could be used as potent inhibitors as anticancer drugs.

Conclusion: Promising anticancer activity of compounds and compared with cisplatin reference drug suggests that these ligands may contribute as lead compounds in search of new anticancer agents to combat chemo-resistance.
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http://dx.doi.org/10.2147/DDDT.S291579DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7900779PMC
February 2021

Novel Extracellular Electron Transfer Channels in a Gram-Positive Thermophilic Bacterium.

Front Microbiol 2020 11;11:597818. Epub 2021 Jan 11.

Winogradsky Institute of Microbiology, FRC Biotechnology Russian Academy of Sciences, Moscow, Russia.

Biogenic transformation of Fe minerals, associated with extracellular electron transfer (EET), allows microorganisms to exploit high-potential refractory electron acceptors for energy generation. EET-capable thermophiles are dominated by hyperthermophilic archaea and Gram-positive bacteria. Information on their EET pathways is sparse. Here, we describe EET channels in the thermophilic Gram-positive bacterium that drive exoelectrogenesis and rapid conversion of amorphous mineral ferrihydrite to large magnetite crystals. Microscopic studies indicated biocontrolled formation of unusual formicary-like ultrastructure of the magnetite crystals and revealed active colonization of anodes in bioelectrochemical systems (BESs) by . The internal structure of micron-scale biogenic magnetite crystals is reported for the first time. Genome analysis and expression profiling revealed three constitutive -type multiheme cytochromes involved in electron exchange with ferrihydrite or an anode, sharing insignificant homology with previously described EET-related cytochromes thus representing novel determinants of EET. Our studies identify these cytochromes as extracellular and reveal potentially novel mechanisms of cell-to-mineral interactions in thermal environments.
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http://dx.doi.org/10.3389/fmicb.2020.597818DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7829351PMC
January 2021

Roadmap on emerging concepts in the physical biology of bacterial biofilms: from surface sensing to community formation.

Phys Biol 2021 Jun 23;18(5). Epub 2021 Jun 23.

Department of Physics and Astronomy, University of Southern California, Los Angeles, California, CA 90089, United States of America.

Bacterial biofilms are communities of bacteria that exist as aggregates that can adhere to surfaces or be free-standing. This complex, social mode of cellular organization is fundamental to the physiology of microbes and often exhibits surprising behavior. Bacterial biofilms are more than the sum of their parts: single-cell behavior has a complex relation to collective community behavior, in a manner perhaps cognate to the complex relation between atomic physics and condensed matter physics. Biofilm microbiology is a relatively young field by biology standards, but it has already attracted intense attention from physicists. Sometimes, this attention takes the form of seeing biofilms as inspiration for new physics. In this roadmap, we highlight the work of those who have taken the opposite strategy: we highlight the work of physicists and physical scientists who use physics to engage fundamental concepts in bacterial biofilm microbiology, including adhesion, sensing, motility, signaling, memory, energy flow, community formation and cooperativity. These contributions are juxtaposed with microbiologists who have made recent important discoveries on bacterial biofilms using state-of-the-art physical methods. The contributions to this roadmap exemplify how well physics and biology can be combined to achieve a new synthesis, rather than just a division of labor.
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http://dx.doi.org/10.1088/1478-3975/abdc0eDOI Listing
June 2021

Ultrastructural observations on the oncomiracidium epidermis and adult tegument of Discocotyle sagittata, a monogenean gill parasite of salmonids.

Parasitol Res 2021 Mar 12;120(3):899-910. Epub 2021 Jan 12.

School of Biosciences, Cardiff University, Cardiff, CF10 3AX, UK.

During their different life stages, parasites undergo remarkable morphological, physiological, and behavioral "metamorphoses" to meet the needs of their changing habitats. This is even true for ectoparasites, such as the monogeneans, which typically have a free-swimming larval stage (oncomiracidium) that seeks out and attaches to the external surfaces of fish where they mature. Before any obvious changes occur, there are ultrastructural differences in the oncomiracidium's outer surface that prepare it for a parasitic existence. The present findings suggest a distinct variation in timing of the switch from oncomiracidia epidermis to the syncytial structure of the adult tegument and so, to date, there are three such categories within the Monogenea: (1) Nuclei of both ciliated cells and interciliary cytoplasm are shed from the surface layer and the epidermis becomes a syncytial layer during the later stages of embryogenesis; (2) nuclei of both ciliated cells and interciliary syncytium remain distinct and the switch occurs later after the oncomiracidia hatch (as in the present study); and (3) the nuclei remain distinct in the ciliated epidermis but those of the interciliary epidermis are lost during embryonic development. Here we describe how the epidermis of the oncomiracidium of Discocotyle sagittata is differentiated into two regions, a ciliated cell layer and an interciliary, syncytial cytoplasm, both of which are nucleated. The interciliary syncytium extends in-between and underneath the ciliated cells and sometimes covers part of their apical surfaces, possibly the start of their shedding process. The presence of membranous whorls and pyknotic nuclei over the surface are indicative of membrane turnover suggesting that the switch in epidermis morphology is already initiated at this stage. The body tegument and associated putative sensory receptors of subadult and adult D. sagittata are similar to those in other monogeneans.
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http://dx.doi.org/10.1007/s00436-020-07045-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7889578PMC
March 2021

Electrolocation? The evidence for redox-mediated taxis in Shewanella oneidensis.

Mol Microbiol 2021 06 7;115(6):1069-1079. Epub 2020 Dec 7.

BioTechnology Institute and Department of Plant and Microbial Biology, University of Minnesota - Twin Cities, St. Paul, MN, USA.

Shewanella oneidensis is a dissimilatory metal reducing bacterium and model for extracellular electron transfer (EET), a respiratory mechanism in which electrons are transferred out of the cell. In the last 10 years, migration to insoluble electron acceptors for EET has been shown to be nonrandom and tactic, seemingly in the absence of molecular or energy gradients that typically allow for taxis. As the ability to sense, locate, and respire electrodes has applications in bioelectrochemical technology, a better understanding of taxis in S. oneidensis is needed. While the EET conduits of S. oneidensis have been studied extensively, its taxis pathways and their interplay with EET are not yet understood, making investigation into taxis phenomena nontrivial. Since S. oneidensis is a member of an EET-encoding clade, the genetic circuitry of taxis to insoluble acceptors may be conserved. We performed a bioinformatic analysis of Shewanella genomes to identify S. oneidensis chemotaxis orthologs conserved in the genus. In addition to the previously reported core chemotaxis gene cluster, we identify several other conserved proteins in the taxis signaling pathway. We present the current evidence for the two proposed models of EET taxis, "electrokinesis" and flavin-mediated taxis, and highlight key areas in need of further investigation.
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http://dx.doi.org/10.1111/mmi.14647DOI Listing
June 2021

Electrochemical evidence for in situ microbial activity at the Deep Mine Microbial Observatory (DeMMO), South Dakota, USA.

Geobiology 2021 03 14;19(2):173-188. Epub 2020 Nov 14.

Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA.

The subsurface is Earth's largest reservoir of biomass. Micro-organisms are the dominant lifeforms in this habitat, but the nature of their in situ activities remains largely unresolved. At the Deep Mine Microbial Observatory (DeMMO) located in the Sanford Underground Research Facility (SURF) in Lead, South Dakota (USA), we performed in situ electrochemical incubations designed to assess the potential for deep groundwater microbial communities to utilize extracellular electron transfer to support microbial respiration. DeMMO 4 was chosen for its stable geochemistry and microbial community. Graphite and indium tin oxide electrodes poised at -200 mV versus SHE were incubated along with open circuit controls and various minerals in a parallel flow reactor that split access to fluids across different treatments. From the patterns of net current over time (fluctuating between anodic and cathodic currents over the course of a few days to weeks) and the catalytic features measured using periodic cyclic voltammetry, evidence of both oxidative and reductive microbe-electrode interactions was observed. The predominant catalytic activity ranged from -210 to -120 mV. The observed temporal variability in electrochemical activity was unexpected given the documented stability in major geochemical parameters. This suggests that the accessed fluids are more heterogeneous in electrochemically active microbial populations than previously predicted from the stable community composition. As previously reported, the fracture fluid and surface-attached microbial communities at SURF differed significantly. However, only minimal differences in community composition were observed between poised potential electrodes, open circuit electrodes, and mineral incubations. These data support that in this environment the ability to attach to surfaces is a stronger driver of microbial community structure than the type or reactivity of the surface. We demonstrate that insight into specific activities can be gained from electrochemical methods, specifically chronoamperometry coupled with routine cyclic voltammetry, which provide a sensitive approach to evaluate microbial activities in situ.
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http://dx.doi.org/10.1111/gbi.12420DOI Listing
March 2021

Synthesis, In Silico and In Vitro Assessment of New Quinazolinones as Anticancer Agents via Potential AKT Inhibition.

Molecules 2020 Oct 18;25(20). Epub 2020 Oct 18.

Chemistry Department, Faculty of Science, South Valley University, Qena 83523, Egypt.

A series of novel quinazolinone derivatives (-) was synthesized and examined for their cytotoxicity to HepG2, MCF-7, and Caco-2 in an MTT assay. Among these derivatives, compounds and exhibited significant cytotoxic activity against Caco-2, HepG2, and MCF-7 cancer cells. Compound had more significant inhibitory effects than compound on Caco-2, HepG2, and MCF-7 cell lines, with IC values of 23.31 ± 0.09, 53.29 ± 0.25, and 72.22 ± 0.14µM, respectively. The AKT pathway is one of human cancer's most often deregulated signals. AKT is also overexpressed in human cancers such as glioma, lung, breast, ovarian, gastric, and pancreas. A molecular docking study was performed to analyze the inhibitory action of newly synthetic quinazolinone derivatives against AKT1 protein. Molecular docking simulations were found to be in accordance with in vitro studies, and hence supported the biological activity. The results suggested that compounds and could be used as drug candidates for cancer therapy via its potential inhibition of AKT1 as described by docking study.
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http://dx.doi.org/10.3390/molecules25204780DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7594071PMC
October 2020

Impacts of physicochemical and heavy metal parameters on infestation level of the monogeneans, spp. infesting Nile catfish, of different water localities in Nile Delta, Egypt.

J Parasit Dis 2020 Sep 27;44(3):579-589. Epub 2020 May 27.

Zoology Department, Faculty of Science, Mansoura University, Mansoura, Egypt.

Fish parasites can be used as bio-indicators to evaluate pollution degree in aquatic ecosystems. Limited research has, however, investigated the potentiality of these parasitic worms to tolerate various environmental factors. This study, therefore, investigated whether the gill, monogenean parasites of Forskål, 1775 are potential bio-indicators of aquatic ecosystem health. The seasonal differences in prevalence, mean intensity and abundance of species of varied between each other and between the three localities. Most species exhibited their highest prevalence, mean intensity and abundance in Spring and/or Summer and their lowest values in Autumn and/or Winter. The seasonal differences in prevalence were significant for and while a significant difference in the mean intensity between different seasons was recorded only for . Also, seasonal differences in the abundance were highly significant for and significant for The total dissolved solids, Chlorides, Sulphate, Sodium, Cadmium and Lead were higher at Manzala Lake than standard permissible limits. The pH has significant correlations with the infestation levels of spp. Dissolved oxygen showed a highly significant positive correlation with the mean intensity of and a significant positive correlation with the abundance of . Iron was the only heavy metal to record a significant positive relationship with the mean intensity of . It is noteworthy that species were found to have a noticeable ability to resist the effect of hazardous concentrations of many physicochemical and heavy metals parameters. Therefore, it is highly recommended that these monogeneans could be regarded as bio-indicators for water quality.
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http://dx.doi.org/10.1007/s12639-020-01231-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7410912PMC
September 2020

Spatiotemporal mapping of bacterial membrane potential responses to extracellular electron transfer.

Proc Natl Acad Sci U S A 2020 08 3;117(33):20171-20179. Epub 2020 Aug 3.

Department of Physics and Astronomy, University of Southern California, Los Angeles, CA 90089;

Extracellular electron transfer (EET) allows microorganisms to gain energy by linking intracellular reactions to external surfaces ranging from natural minerals to the electrodes of bioelectrochemical renewable energy technologies. In the past two decades, electrochemical techniques have been used to investigate EET in a wide range of microbes, with emphasis on dissimilatory metal-reducing bacteria, such as MR-1, as model organisms. However, due to the typically bulk nature of these techniques, they are unable to reveal the subpopulation variation in EET or link the observed electrochemical currents to energy gain by individual cells, thus overlooking the potentially complex spatial patterns of activity in bioelectrochemical systems. Here, to address these limitations, we use the cell membrane potential as a bioenergetic indicator of EET by MR-1 cells. Using a fluorescent membrane potential indicator during in vivo single-cell-level fluorescence microscopy in a bioelectrochemical reactor, we demonstrate that membrane potential strongly correlates with EET. Increasing electrode potential and associated EET current leads to more negative membrane potential. This EET-induced membrane hyperpolarization is spatially limited to cells in contact with the electrode and within a near-electrode zone (<30 μm) where the hyperpolarization decays with increasing cell-electrode distance. The high spatial and temporal resolution of the reported technique can be used to study the single-cell-level dynamics of EET not only on electrode surfaces, but also during respiration of other solid-phase electron acceptors.
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http://dx.doi.org/10.1073/pnas.2000802117DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7443868PMC
August 2020

Type IV Pili-Independent Photocurrent Production by the Cyanobacterium sp. PCC 6803.

Front Microbiol 2020 25;11:1344. Epub 2020 Jun 25.

School of Molecular Sciences, Arizona State University, Tempe, AZ, United States.

Biophotovoltaic devices utilize photosynthetic organisms such as the model cyanobacterium sp. PCC 6803 () to generate current for power or hydrogen production from light. These devices have been improved by both architecture engineering and genetic engineering of the phototrophic organism. However, genetic approaches are limited by lack of understanding of cellular mechanisms of electron transfer from internal metabolism to the cell exterior. Type IV pili have been implicated in extracellular electron transfer (EET) in some species of heterotrophic bacteria. Furthermore, conductive cell surface filaments have been reported for cyanobacteria, including . However, it remains unclear whether these filaments are type IV pili and whether they are involved in EET. Herein, a mediatorless electrochemical setup is used to compare the electrogenic output of wild-type to that of a Δ mutant that cannot produce type IV pili. No differences in photocurrent, i.e., current in response to illumination, are detectable. Furthermore, measurements of individual pili using conductive atomic force microscopy indicate these structures are not conductive. These results suggest that pili are not required for EET by , supporting a role for shuttling of electrons via soluble redox mediators or direct interactions between the cell surface and extracellular substrates.
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http://dx.doi.org/10.3389/fmicb.2020.01344DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7344198PMC
June 2020

Novel Quinazolin-2,4-Dione Hybrid Molecules as Possible Inhibitors Against Malaria: Synthesis and Molecular Docking Studies.

Front Mol Biosci 2020 5;7:105. Epub 2020 Jun 5.

Chemistry Department, Faculty of Science, South Valley University, Qena, Egypt.

The research explores the synthesis of a series of novel hybrid quinazolin-2,4-dione analogs bearing acetyl/amide bridged-nitrogen heterocyclic moieties such as azetidinone, pyrrole, oxazole, oxadiazole, thiazole, pyrazole, and thiazolidine scaffolds . The newly synthesized compounds were structurally confirmed by means of IR, H-NMR, C-NMR, MS and elemental analysis. In addition, an molecular docking analysis of new compounds and standard drug (Chloroquine) has been performed to analyze the binding modes of interaction to the putative active site of Dihydroorotate dehydrogenase (DHODH). Aiming to search for potentially better antimalarials, a modern approach has been undertaken to identify new quinazolin-2,4-dione derivatives targeting DHODH. The identification of antimalarial activity of the newly synthesized compounds by using experimental techniques is expensive and requires extensive pains and labor. The compound showed the highest binding affinity against DHODH. Moreover, the electrostatic potential (ESP) of the docked molecules was also calculated. Further, the pharmacokinetic properties (ADMET) of the prepared compounds were predicted through technique.
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http://dx.doi.org/10.3389/fmolb.2020.00105DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7291371PMC
June 2020

Chiral Pyridine-3,5-bis- (L-phenylalaninyl-L-leucinyl) Schiff Base Peptides as Potential Anticancer Agents: Design, Synthesis, and Molecular Docking Studies Targeting Lactate Dehydrogenase-A.

Molecules 2020 Feb 29;25(5). Epub 2020 Feb 29.

Zoology Department, Bioproducts Research Chair, Faculty of Science, King Saud University, Riyadh 11451, Saudi Arabia.

A series of branched tetrapeptide Schiff bases - were designed and synthesized from corresponding tetrapeptide hydrazide as a starting material.In vitroevaluation of the synthesized compounds - against breast MCF-7 carcinoma cells identified their excellent anticancer potency, with IC ranging from 8.12 ± 0.14 to 17.55 ± 0.27 μM in comparison with the references, cisplatin and milaplatin (IC= 13.34 ± 0.11and 18.43 ± 0.13 μM, respectively). Furthermore, all derivatives demonstrated promising activity upon evaluation of theirin vitroandin vivosuppression of p53 ubiquitination and inhibition assessment for LDHA kinase. Finally, molecular docking studies were performed to predict the possible binding features of the potent derivatives within the ATP pocket of LDHA in an attempt to get a lead for developing a more potent LDHA inhibitor with anti-proliferative potency.
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http://dx.doi.org/10.3390/molecules25051096DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7179198PMC
February 2020

Modified Screen-Printed Potentiometric Sensors based on Man-Tailored Biomimetics for Diquat Herbicide Determination.

Int J Environ Res Public Health 2020 02 11;17(4). Epub 2020 Feb 11.

Pharmaceutical Chemistry Department, Drug Exploration & Development Chair (DEDC), College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia.

Screen-printed platforms integrated with molecularly imprinted polymers (MIP) were fabricated and characterized as potentiometric sensors for diquat (DQ). The synthesized MIP beads were studied as sensory carriers in plasticized poly(vinyl chloride) membranes. The sensors were constructed by using poly(3,4-ethylenedioxythiophene) (PEDOT) as solid-contact material to diminish charge-transfer resistance and water layer potential. Conventional ion-selective electrodes (ISEs) with internal filling solution were used for comparison. The designed electrodes showed near Nernstian slopes of 28.2 ± 0.7 (r² = 0.999) over the concentration range of 1.0 × 10-1.0 × 10 M with the limit of detection 0.026 µg/mL over the pH range 4.2-9.0. The electrode exhibited good selectivity for diquat cations over a large number of organic and inorganic cations. The sensor was successfully introduced for direct measurement of diquat content in commercial pesticide preparations and different spiked potato samples. The results showed that the proposed electrode has a fast and stable response, good reproducibility, and applicability for direct assessment of diquat content. The proposed potentiometric method is simple and accurate in comparison with the reported HPLC methods. Besides, it is applicable to turbid and colored sample solutions.
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http://dx.doi.org/10.3390/ijerph17041138DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7068347PMC
February 2020

New Potent 5α- Reductase and Aromatase Inhibitors Derived from 1,2,3-Triazole Derivative.

Molecules 2020 Feb 5;25(3). Epub 2020 Feb 5.

Chemistry of Natural and Microbial Products Department, Pharmaceutical and Drug Industries Research Division, National Research Centre, Dokki, Cairo 12622, Egypt.

This work describes the utility of pyrazole-4-carbaldehyde as starting material for the synthesis of a novel potent series of 5α-reductase and aromatase inhibitors derived from 1,2,3-triazole derivative. Condensation of with active methylene and different amino pyrazoles produced the respective Schiff bases -, and . On the other hand, was reacted with ethyl cyanoacetate and thiourea in one-pot reaction to afford the pyrazolo-6- thioxopyridin-2-[3]-one (). Moreover, α-β unsaturated chalcone derivative was prepared via the reaction of compound with -methoxy acetophenone, which in turn reacted with each of ethyl cyanoacetate, malononitrile, hydrazine hydrate, and thiosemicarbazide to afford the corresponding pyridine and pyrazole derivatives , , and The structure of newly synthesized compounds was characterized by analytical and spectroscopic data (IR, MS and NMR) All new compounds were evaluated against 5α-reductase and aromatase inhibitors and the results showed that many of these compounds inhibit 5α-reductase and aromatase activity; compound was found to be the highest potency among the tested samples comparing with the reference drugs.
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http://dx.doi.org/10.3390/molecules25030672DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7037409PMC
February 2020

Synthesis, Characterization, Antibacterial Activity, and Computer-Aided Design of Novel Quinazolin-2,4-dione Derivatives as Potential Inhibitors Against .

Evol Bioinform Online 2020 6;16:1176934319897596. Epub 2020 Jan 6.

Chemistry Department, Faculty of Science, South Valley University, Qena, Egypt.

Cholera is a bacterial disease featured by dehydration and severe diarrhea. It is mainly caused by alimentary infection with . Due to the wide applicability of quinazolin-2,4-dione compounds in medicinal and pharmaceutical chemistry, a new series of -containing heterocyclic compounds was synthesized. We used the docking method to test the efficacy of quinazolin-2,4-dione compounds in the prevention of cholera in humans. The newly synthesized compounds showed strong interactions and good binding affinity to outer membrane protein OmpU. Moreover, the pharmacokinetic properties of the newly synthesized compounds, such as absorption, distribution, metabolic, excretion, and toxicity (ADMET), were predicted through methods. Compounds with acceptable pharmacokinetic properties were tested as novel ligand molecules. The synthesized compounds were evaluated in vitro for their antibacterial activity properties against Gram-negative O78 strain using the minimum inhibition concentration (MIC) method. Compounds and showed reproducible, effective antibacterial activity. Hence, our study concludes that the quinazolin-2,4-dione derivatives to may be used as promising drug candidates with potential value for the treatment of cholera disease.
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http://dx.doi.org/10.1177/1176934319897596DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6945456PMC
January 2020

Spin-Dependent Electron Transport through Bacterial Cell Surface Multiheme Electron Conduits.

J Am Chem Soc 2019 12 11;141(49):19198-19202. Epub 2019 Nov 11.

Department of Chemical and Biological Physics , Weizmann Institute of Science , Rehovot 76100 , Israel.

Multiheme cytochromes, located on the bacterial cell surface, function as long-distance (>10 nm) electron conduits linking intracellular reactions to external surfaces. This extracellular electron transfer process, which allows microorganisms to gain energy by respiring solid redox-active minerals, also facilitates the wiring of cells to electrodes. While recent studies have suggested that a chiral induced spin selectivity effect is linked to efficient electron transmission through biomolecules, this phenomenon has not been investigated in extracellular electron conduits. Using magnetic conductive probe atomic force microscopy, Hall voltage measurements, and spin-dependent electrochemistry of the decaheme cytochromes MtrF and OmcA from the metal-reducing bacterium MR-1, we show that electron transport through these extracellular conduits is spin-selective. Our study has implications for understanding how spin-dependent interactions and magnetic fields may control electron transport across biotic-abiotic interfaces in both natural and biotechnological systems.
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http://dx.doi.org/10.1021/jacs.9b09262DOI Listing
December 2019

Novel Solid-State Potentiometric Sensors Using Polyaniline (PANI) as A Solid-Contact Transducer for Flucarbazone Herbicide Assessment.

Polymers (Basel) 2019 Nov 1;11(11). Epub 2019 Nov 1.

Pharmaceutical Chemistry Department, College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia.

Novel potentiometric solid-contact ion-selective electrodes (SC/ISEs) based on molecularly imprinted polymers (MIPs) as sensory carriers (MIP/PANI/ISE) were prepared and characterized as potentiometric sensors for flucarbazone herbicide anion. However, aliquat S 336 was also studied as a charged carrier in the fabrication of Aliquat/PANI/ISEs for flucarbazone monitoring. The polyaniline (PANI) film was inserted between the ion-sensing membrane (ISM) and the electronic conductor glassy carbon substrate (GC). The sensors showed a noticeable response towards flucarbazone anions with slopes of -45.5 ± 1.3 (r = 0.9998) and -56.3 ± 1.5 (r = 0.9977) mV/decade over the range of 10-10, 10-10 M and detection limits of 5.8 × 10 and 8.5 × 10 M for MIP/PANI/ISE and Aliguat/PANI/ISE, respectively. The selectivity and long-term potential stability of all presented ISEs were investigated. The short-term potential and electrode capacitances were studied and evaluated using chronopotentiometry and electrochemical impedance spectrometry (EIS). The proposed ISEs were introduced for the direct measurement of flucarbazone herbicide in different soil samples sprayed with flucarbazone herbicide. The results agree well with the results obtained using the standard liquid chromatographic method (HPLC).
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http://dx.doi.org/10.3390/polym11111796DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6918223PMC
November 2019

Novel Aminoacridine Sensors Based on Molecularly Imprinted Hybrid Polymeric Membranes for Static and Hydrodynamic Drug Quality Control Monitoring.

Materials (Basel) 2019 Oct 12;12(20). Epub 2019 Oct 12.

Pharmaceutical Chemistry Department, Drug Exploration & Development Chair (DEDC), College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia.

Novel biomimetic potentiometric ion-selective electrodes (ISEs) were fabricated and designed for the assessment of aminoacridine (ACR) based on newly synthesized imprinted polymer (MIP) membranes. Thermal polymerization of methacrylic acid (MAA) or acrylamide (AM) as function monomer, aminoacridine as a template and ethylene glycol dimethacrylate (EGDMA) as across-linker, were utilizedto give the molecular recognition part. The membranes of sensors I andII consist of MIP based MAA and AM, respectively, dispersed in a poly(vinyl chloride) membrane plasticized with dioctyl phthalate (DOP) in the ratio of 3.0 wt%, 32.2 wt% and 64.8 wt%, respectively. Sensors III and IV were similarly prepared with added 1.0 wt% tetraphenyl borate (TPB) as an anionic discriminator. Sensors I and II exhibited near-Nernstian potential response to ACR with slopes of 51.2 ± 1.3 and 50.5 ± 1.4 mV/decade in a 0.01 M phosphate buffer of pH 6.0. The linear response coversthe concentration range of 5.2 × 10 to 1.0 × 10 M with a detection limit of 0.05 and 0.17 μg/mL for sensors I and II, respectively. The performance characteristics of these sensors were evaluated under static and hydrodynamic mode of operations. They were used for quality control assessment of aminoacridine in some pharmaceutical preparations and biological samples.
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http://dx.doi.org/10.3390/ma12203327DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6829627PMC
October 2019

Towards breast cancer targeting: Synthesis of tetrahydroindolocarbazoles, antibreast cancer evaluation, uPA inhibition, molecular genetic and molecular modelling studies.

Bioorg Chem 2019 12 1;93:103332. Epub 2019 Oct 1.

Department of Applied Organic Chemistry, National Research Centre, 12622 Dokki, Giza, Egypt. Electronic address:

A series of some new tetrahydroindolocarbazole derivatives has been synthesized. The structure of the synthesized compounds has been confirmed by different spectroscopic techniques such as IR, NMR, elemental analysis and mass spectrometry. The target compounds were evaluated for their antitumor activity against breast cancer cell line MCF-7, their GI% and their LC have been determined. Six of the synthesized compounds exhibited GI% values against MCF-7 cell lines exceeding 70% ranging from 71.9 to 85.0% in addition that compound 11 expressed GI% values of 99.9% and considered the most active derivatives among the synthesized ones. Compound 11 showed a remarkable decrease of u PA level to 3.5 ng/ml compared to DOX. Compound 5, 11 and 15 showed significant decrease in expression of MTAP and CDKN2A, in addition to a remarkable decrease in DNA damage comet assay method. Molecular modeling studies were performed to interpretate the behavior of active ligands as uPA inhibitors.
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http://dx.doi.org/10.1016/j.bioorg.2019.103332DOI Listing
December 2019

In situ imaging of the bacterial flagellar motor disassembly and assembly processes.

EMBO J 2019 07 20;38(14):e100957. Epub 2019 May 20.

Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA.

The self-assembly of cellular macromolecular machines such as the bacterial flagellar motor requires the spatio-temporal synchronization of gene expression with proper protein localization and association of dozens of protein components. In Salmonella and Escherichia coli, a sequential, outward assembly mechanism has been proposed for the flagellar motor starting from the inner membrane, with the addition of each new component stabilizing the previous one. However, very little is known about flagellar disassembly. Here, using electron cryo-tomography and sub-tomogram averaging of intact Legionella pneumophila, Pseudomonas aeruginosa, and Shewanella oneidensis cells, we study flagellar motor disassembly and assembly in situ. We first show that motor disassembly results in stable outer membrane-embedded sub-complexes. These sub-complexes consist of the periplasmic embellished P- and L-rings, and bend the membrane inward while it remains apparently sealed. Additionally, we also observe various intermediates of the assembly process including an inner-membrane sub-complex consisting of the C-ring, MS-ring, and export apparatus. Finally, we show that the L-ring is responsible for reshaping the outer membrane, a crucial step in the flagellar assembly process.
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http://dx.doi.org/10.15252/embj.2018100957DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6627242PMC
July 2019

Novel phthalimide based analogues: design, synthesis, biological evaluation, and molecular docking studies.

J Enzyme Inhib Med Chem 2019 Dec;34(1):1259-1270

e Pharmaceutical Chemistry Department, Drug Exploration & Development Chair (DEDC) , College of Pharmacy, King Saud University , Riyadh , Saudi Arabia.

Pyrazolylphthalimide derivative was synthesized and reacted with different reagents to afford the target compounds imidazopyrazoles , pyrazolopyrimidines and pyrazolotriazines containing phthalimide moiety. The prepared compounds were established by different spectral data and elemental analyses. Additionally, all synthesized derivatives were screened for their antibacterial activity against four types of Gram + ve and Gram-ve strains, and for antifungal activity against two fungi micro-organisms by well diffusion method. Moreover, the antiproliferative activity was tested for all compounds against human liver (HepG-2) cell line in comparison with the reference vinblastine. Moreover, drug-likeness and toxicity risk parameters of the newly synthesized compounds were calculated using studies. The data from structure-actvity relationship (SAR) analysis suggested that phthalimide derivative bearing 3-aminopyrazolone moiety, illustrated the best antimicrobial and antitumor activities and might be considered as a lead for further optimization. To investigate the mechanism of the antimicrobial and anticancer activities, enzymatic assay and molecular docking studies were carried out on topoisomerase II DNA gyrase B and VEGFR-2 enzymes.
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http://dx.doi.org/10.1080/14756366.2019.1637861DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6691772PMC
December 2019

Potent Anti-Ovarian Cancer with Inhibitor Activities on both Topoisomerase II and BRAF of Synthesized Substituted Estrone Candidates.

Molecules 2019 May 29;24(11). Epub 2019 May 29.

Atos Pharma, Elkatyba Land, Belbis 44621, El Sharkya, Egypt.

A series of 16-(α-alkoxyalkane)-17-hydrazino-estra-1(10),2,4-trien[17,16-c]-3-ol (-) and estra-1(10),2,4-trien-[17,16-c]pyrazoline-3-ol derivatives (-) were synthesized from corresponding arylidines which was prepared from estrone as starting material. Condensation of 1 with aldehydes gave the corresponding arylidine derivatives which were treated with hydrazine derivatives in alcohols to give the corresponding derivatives -, respectively. Additionally, treatment of with methyl- or phenylhydrazine in ethanolic potassium hydroxide afforded the corresponding N-substituted pyrazoline derivatives -, respectively. All these derivatives showed potent anti-ovarian cancer both in vitro and in vivo The mechanism of anti-ovarian cancer was suggested to process via topoisomerase II and BRAF inhibition.
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http://dx.doi.org/10.3390/molecules24112054DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6600292PMC
May 2019

Old leaves accumulate more heavy metals than other parts of the desert shrub at a traffic-polluted site as assessed by two analytical techniques.

Int J Phytoremediation 2019 28;21(12):1254-1262. Epub 2019 May 28.

Institute of Environment & Sustainable Development, Banaras Hindu University , Varanasi , India.

is a perennial big shrub that has the potential to accumulate high concentrations of heavy metals. Metal sequestration in old organs has been considered as a mechanism for plant survival in polluted soils. The aim of the present study was to assess the role of the old leaves as a sink for HMs accumulation in . Two instruments were used: atomic absorption spectroscopy (AAS) and X-ray fluorescence (XRF) microscopy. Soil and plant samples were collected from around one of the worst congested traffic areas in the United Arab Emirates (UAE). Samples from roots, stem, and green and old leaves were prepared and analyzed by both instruments. was able to concentrate Fe, Mn, Sr, and Zn in the roots, but their translocation to stem and green leaves was low. Old leaves had greater ability to accumulate significantly higher concentrations of different metals, especially Fe and Sr, than other parts of the plants, indicating that uses these metabolically less-active leaves as sinks for heavy metals. Fe and Sr attained higher bioconcentration and accumulation values, compared to Zn and Mn. There were significant positive correlations between XRF and AAS for all elements in the different organs.
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http://dx.doi.org/10.1080/15226514.2019.1619164DOI Listing
October 2019
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