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  • 1.
    Baldassarre, Maurizio
    et al.
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Li, Chenge
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Eremina, Nadejda
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Goormaghtigh, Erik
    Barth, Andreas
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Simultaneous Fitting of Absorption Spectra and Their Second Derivatives for an Improved Analysis of Protein Infrared Spectra2015In: Molecules, ISSN 1420-3049, E-ISSN 1420-3049, Vol. 20, no 7, p. 12599-12622Article in journal (Refereed)
    Abstract [en]

    Infrared spectroscopy is a powerful tool in protein science due to its sensitivity to changes in secondary structure or conformation. In order to take advantage of the full power of infrared spectroscopy in structural studies of proteins, complex band contours, such as the amide I band, have to be decomposed into their main component bands, a process referred to as curve fitting. In this paper, we report on an improved curve fitting approach in which absorption spectra and second derivative spectra are fitted simultaneously. Our approach, which we name co-fitting, leads to a more reliable modelling of the experimental data because it uses more spectral information than the standard approach of fitting only the absorption spectrum. It also avoids that the fitting routine becomes trapped in local minima. We have tested the proposed approach using infrared absorption spectra of three mixed α/β proteins with different degrees of spectral overlap in the amide I region: ribonuclease A, pyruvate kinase, and aconitase.

  • 2. Barzegar, Hamid Reza
    et al.
    Nitze, Florian
    Malolepszy, Artur
    Stobinski, Leszek
    Tai, Cheuk-Wai
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Wagberg, Thomas
    Water Assisted Growth of C-60 Rods and Tubes by Liquid-Liquid Interfacial Precipitation Method2012In: Molecules, ISSN 1420-3049, E-ISSN 1420-3049, Vol. 17, no 6, p. 6840-6853Article in journal (Refereed)
    Abstract [en]

    C-60 nanorods with hexagonal cross sections are grown using a static liquid-liquid interfacial precipitation method in a system of C-60/m-dichlorobenzene solution and ethanol. Adding water to the ethanol phase leads instead to C-60 tubes where both length and diameter of the C-60 tubes can be controlled by the water content in the ethanol. Based on our observations we find that the diameter of the rods/tubes strongly depends on the nucleation step. We propose a liquid-liquid interface growth model of C-60 rods and tubes based on the diffusion rate of the good C-60 containing solvent into the poor solvent as well as on the size of the crystal seeds formed at the interface between the two solvents. The grown rods and tubes exhibit a hexagonal solvate crystal structure with m-dichlorobenzene solvent molecules incorporated into the crystal structure, independent of the water content. An annealing step at 200 degrees C at a pressure <1 kPa transforms the grown structures into a solvent-free face centered cubic structure. Both the hexagonal and the face centered cubic structures are very stable and neither morphology nor structure shows any signs of degradation after three months of storage.

  • 3. El-Aarag, Bishoy
    et al.
    Magdy, Mohamed
    AlAjmi, Mohamed F.
    Khalifa, Shaden A. M.
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    El-Seedi, Hesham R.
    Melittin Exerts Beneficial Effects on Paraquat-Induced Lung Injuries in Mice by Modifying Oxidative Stress and Apoptosis2019In: Molecules, ISSN 1420-3049, E-ISSN 1420-3049, Vol. 24, no 8, article id 1498Article in journal (Refereed)
    Abstract [en]

    Melittin (MEL) is a 26-amino acid peptide with numerous biological activities. Paraquat (PQ) is one of the most widely used herbicides, although it is extremely toxic to humans. To date, PQ poisoning has no effective treatment, and therefore the current study aimed to assess for the first time the possible effects of MEL on PQ-induced lung injuries in mice. Mice received a single intraperitoneal (IP) injection of PQ (30 mg/kg), followed by IP treatment with MEL (0.1 and 0.5 mg/kg) twice per week for four consecutive weeks. Histological alterations, oxidative stress, and apoptosis in the lungs were studied. Hematoxylin and eosin (H&E) staining indicated that MEL markedly reduced lung injuries induced by PQ. Furthermore, treatment with MEL increased superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activity, and decreased malonaldehyde (MDA) and nitric oxide (NO) levels in lung tissue homogenates. Moreover, immunohistochemical staining showed that B-cell lymphoma-2 (Bcl-2) and survivin expressions were upregulated after MEL treatment, while Ki-67 expression was downregulated. The high dose of MEL was more effective than the low dose in all experiments. In summary, MEL efficiently reduced PQ-induced lung injuries in mice. Specific pharmacological examinations are required to determine the effectiveness of MEL in cases of human PQ poisoning.

  • 4. El-Saied, Fathy
    et al.
    El-Aarag, Bishoy
    Salem, Tarek
    Said, Ghada
    Khalifa, Shaden A. M.
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute. Novum, Sweden.
    El-Seedi, Hesham R.
    Synthesis, Characterization, and In Vivo Anti-Cancer Activity of New Metal Complexes Derived from Isatin-N(4)antipyrinethiosemicarbazone Ligand Against Ehrlich Ascites Carcinoma Cells2019In: Molecules, ISSN 1420-3049, E-ISSN 1420-3049, Vol. 24, no 18, article id 3313Article in journal (Refereed)
    Abstract [en]

    The current study aimed to synthesize new metal coordination complexes with potential biomedical applications. Metal complexes were prepared via the reaction of isatin-N(4)anti- pyrinethiosemicarbazone ligand 1 with Cu(II), Ni(II), Co(II), Zn(II), and Fe(III) ions. The obtained metal complexes 2-12 were characterized using elemental, spectral (H-1-NMR, EPR, Mass, IR, UV-Vis) and thermal (TGA) techniques, as well as magnetic moment and molar conductance measurements. In addition, their geometries were studied using EPR and UV-Vis spectroscopy. To evaluate the in vivo anti-cancer activities of these complexes, the ligand 1 and its metal complexes 2, 7 and 9 were tested against solid tumors. The solid tumors were induced by subcutaneous (SC) injection of Ehrlich ascites carcinoma (EAC) cells in mice. The impact of the selected complexes on the reduction of tumor volume was determined. Also, the expression levels of vascular endothelial growth factor (VEGF) and cysteine aspartyl-specific protease-7 (caspase-7) in tumor and liver tissues of mice bearing EAC tumor were determined. Moreover, their effects on alanine transaminase (ALT), aspartate transaminase (AST), albumin, and glucose levels were measured. The results revealed that the tested compounds, especially complex 9, reduced tumor volume, inhibited the expression of VEGF, and induced the expression of caspase-7. Additionally, they restored the levels of ALT, AST, albumin, and glucose close to their normal levels. Taken together, our newly synthesized metal complexes are promising anti-cancer agents against solid tumors induced by EAC cells as supported by the inhibition of VEGF and induction of caspase-7.

  • 5.
    Gudmundsson, Arnar
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bäckvall, Jan-E.
    Stockholm University, Faculty of Science, Department of Organic Chemistry. Mid Sweden University, Sweden.
    On the Use of Iron in Organic Chemistry2020In: Molecules, ISSN 1420-3049, E-ISSN 1420-3049, Vol. 25, no 6Article, review/survey (Refereed)
    Abstract [en]

    Transition metal catalysis in modern organic synthesis has largely focused on noble transition metals like palladium, platinum and ruthenium. The toxicity and low abundance of these metals, however, has led to a rising focus on the development of the more sustainable base metals like iron, copper and nickel for use in catalysis. Iron is a particularly good candidate for this purpose due to its abundance, wide redox potential range, and the ease with which its properties can be tuned through the exploitation of its multiple oxidation states, electron spin states and redox potential. This is a fact made clear by all life on Earth, where iron is used as a cornerstone in the chemistry of living processes. In this mini review, we report on the general advancements in the field of iron catalysis in organic chemistry covering addition reactions, C-H activation, cross-coupling reactions, cycloadditions, isomerization and redox reactions.

  • 6.
    Oschmann, Michael
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Johansson Holm, Linus
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Pourghasemi-Lati, Monireh
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Verho, Oscar
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Synthesis of Elaborate Benzofuran-2-Carboxamide Derivatives through a Combination of 8-Aminoquinoline Directed C–H Arylation and Transamidation Chemistry2020In: Molecules, ISSN 1420-3049, E-ISSN 1420-3049, Vol. 25, no 2, article id 361Article in journal (Refereed)
    Abstract [en]

    Herein, we present a short and highly modular synthetic route that involves 8-aminoquinoline directed C–H arylation and transamidation chemistry, and which enables access to a wide range of elaborate benzofuran-2-carboxamides. For the directed C–H arylation reactions, Pd catalysis was used to install a wide range of aryl and heteroaryl substituents at the C3 position of the benzofuran scaffold in high efficiency. Directing group cleavage and further diversification of the C3-arylated benzofuran products were then achieved in a single synthetic operation through the utilization of a one-pot, two-step transamidation procedure, which proceeded via the intermediate N-acyl-Boc-carbamates. Given the high efficiency and modularity of this synthetic strategy, it constitutes a very attractive method for generating structurally diverse collections of benzofuran derivatives for small molecule screening campaigns.

  • 7. Rostami, Jowan
    et al.
    Mathew, Aji P.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Edlund, Ulrica
    Zwitterionic Acetylated Cellulose Nanofibrils2019In: Molecules, ISSN 1420-3049, E-ISSN 1420-3049, Vol. 24, no 17, article id 3147Article in journal (Refereed)
    Abstract [en]

    A strategy is devised to synthesize zwitterionic acetylated cellulose nanofibrils (CNF). The strategy included acetylation, periodate oxidation, Schiff base reaction, borohydride reduction, and a quaternary ammonium reaction. Acetylation was performed in glacial acetic acid with a short reaction time of 90 min, yielding, on average, mono-acetylated CNF with hydroxyl groups available for further modification. The products from each step were characterized by FTIR spectroscopy, zeta-potential, SEM-EDS, AFM, and titration to track and verify the structural changes along the sequential modification route.

  • 8. Umek, Tea
    et al.
    Sollander, Karin
    Stockholm University, Faculty of Science, Department of Molecular Biology and Functional Genomics.
    Bergquist, Helen
    Wengel, Jesper
    Lundin, Karin E.
    Smith, C. I. Edvard
    Zain, Rula
    Oligonucleotide Binding to Non-B-DNA in MYC2019In: Molecules, ISSN 1420-3049, E-ISSN 1420-3049, Vol. 24, no 5, article id 1000Article in journal (Refereed)
    Abstract [en]

    MYC, originally named c-myc, is an oncogene deregulated in many different forms of cancer. Translocation of the MYC gene to an immunoglobulin gene leads to an overexpression and the development of Burkitt's lymphoma (BL). Sporadic BL constitutes one subgroup where one of the translocation sites is located at the 5'-vicinity of the two major MYC promoters P-1 and P-2. A non-B-DNA forming sequence within this region has been reported with the ability to form an intramolecular triplex (H-DNA) or a G-quadruplex. We have examined triplex formation at this site first by using a 17 bp triplex-forming oligonucleotide (TFO) and a double strand DNA (dsDNA) target corresponding to the MYC sequence. An antiparallel purine-motif triplex was detected using electrophoretic mobility shift assay. Furthermore, we probed for H-DNA formation using the BQQ-OP based triplex-specific cleavage assay, which indicated the formation of the structure in the supercoiled plasmid containing the corresponding region of the MYC promoter. Targeting non-B-DNA structures has therapeutic potential; therefore, we investigated their influence on strand-invasion of anti-gene oligonucleotides (ON)s. We show that in vitro, non-B-DNA formation at the vicinity of the ON target site facilitates dsDNA strand-invasion of the anti-gene ONs.

  • 9.
    Yu, Yang
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Keil, Philipp
    Hansen, Michael Ryan
    Edén, Mattias
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Improved Magnetization Transfers among Quadrupolar Nuclei in Two-Dimensional Homonuclear Correlation NMR Experiments Applied to Inorganic Network Structures2020In: Molecules, ISSN 1420-3049, E-ISSN 1420-3049, Vol. 225, no 2, article id 337Article in journal (Refereed)
    Abstract [en]

    We demonstrate that supercycles of previously introduced two-fold symmetry dipolar recoupling schemes may be utilized successfully in homonuclear correlation nuclear magnetic resonance (NMR) spectroscopy for probing proximities among half-integer spin quadrupolar nuclei in network materials undergoing magic-angle-spinning (MAS). These (SR212)M, (SR214) M, and (SR218)M recoupling sequences with M = 3 and M = 4 offer comparably efficient magnetization transfers in single-quantum-single-quantum (1Q-1Q) correlation NMR experiments under moderately fast MAS conditions, as demonstrated at 14.1 T and 24 kHz MAS in the contexts of 11B NMR on a Na2O-CaO-B2O3-SiO2 glass and 27Al NMR on the open framework aluminophosphate AlPO-CJ19 [(NH4)2Al4(PO4)4HPO4 H2O]. Numerically simulated magnetization transfers in spin-3/2 pairs revealed a progressively enhanced tolerance to resonance offsets and rf-amplitude errors of the recoupling pulses along the series (SR212) M < (SR214)M < (SR218)M for increasing differences in chemical shifts between the two nuclei. Nonetheless, for scenarios of a relatively minor chemical-shift dispersions (. 3 kHz), the (SR212) M supercycles perform best both experimentally and in simulations.

  • 10. Zahra, Maram Hussein
    et al.
    Salem, Tarek A. R.
    El-Aarag, Bishoy
    Yosri, Nermeen
    EL-Ghlban, Samah
    Zaki, Kholoud
    Marei, Amel H.
    Abd El-Wahed, Aida
    Saeed, Aamer
    Khatib, Alfi
    AlAjmi, Mohamed F.
    Shathili, Abdulrahman M.
    Xiao, Jianbo
    Khalifa, Shaden A. M.
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute. Karolinska University Hospital, Sweden.
    El-Seedi, Hesham R.
    Alpinia zerumbet (Pers.): Food and Medicinal Plant with Potential In Vitro and In Vivo Anti-Cancer Activities2019In: Molecules, ISSN 1420-3049, E-ISSN 1420-3049, Vol. 24, no 13, article id 2495Article in journal (Refereed)
    Abstract [en]

    Background/Aim: Plants play an important role in anti-cancer drug discovery, therefore, the current study aimed to evaluate the biological activity of Alpinia zerumbet (A. zerumbet) flowers. Methods: The phytochemical and biological criteria of A. zerumbet were in vitro investigated as well as in mouse xenograft model. Results: A. zerumbet extracts, specially CH2Cl2 and MeOH extracts, exhibited the highest potent anti-tumor activity against Ehrlich ascites carcinoma (EAC) cells. The most active CH2Cl2 extract was subjected to bioassay-guided fractionation leading to isolatation of the naturally occurring 5,6-dehydrokawain (DK) which was characterized by IR, MS, H-1-NMR and C-13-NMR. A. zerumbet extracts, specially MeOH and CH2Cl2 extracts, exhibited significant inhibitory activity towards tumor volume (TV). Furthermore, A. zerumbet extracts declined the high level of malonaldehyde (MDA) as well as elevated the levels of superoxide dismutase (SOD) and catalase (CAT) in liver tissue homogenate. Moreover, DK showed anti-proliferative action on different human cancer cell lines. The recorded IC50 values against breast carcinoma (MCF-7), liver carcinoma (Hep-G2) and larynx carcinoma cells (HEP-2) were 3.08, 6.8, and 8.7 mu g/mL, respectively. Conclusion: Taken together, these findings open the door for further investigations in order to explore the potential medicinal properties of A. zerumbet.

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