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Florent Le Guern, Tan-Sothea Ouk, Catherine Ouk, Regis Vanderesse, Yves Champavier, Emilie Pinault, Vincent Sol
In order to highlight the potential of photodynamic antimicrobial chemotherapy in case of infections by antibiotic resistant-strains, a new antimicrobial peptide conjugate has been synthesized, consisting of a derivative of polymyxin B and a cationic porphyrin covalently attached together to a spacer. A polymyxin-derived moiety was subjected to a primary structural modification in the replacement of four diaminobutyrate residues with lysine ones. This modification was done in order to strongly reduce bactericidal activity, with the aim to eliminate the potential rise of polymyxin-resistant strains...
January 11, 2018: ACS Medicinal Chemistry Letters
Martina Sundqvist, Amanda Welin, Jonas Elmwall, Veronica Osla, Ulf J Nilsson, Hakon Leffler, Johan Bylund, Anna Karlsson
Galectin-3 is an endogenous β-galactoside-binding lectin comprising a carbohydrate recognition domain (CRD) linked to a collagen-like N-domain. Both domains are required for galectin-3 to induce cellular effects; a C-terminal fragment of galectin-3, galectin-3C, containing the CRD but lacking the N-domain, binds cell surface glycoconjugates but does not induce cellular effects since cross-linking promoted by the N-domain is thought to be required. Instead, galectin-3C is proposed to antagonize the effects of galectin-3 by competing for binding sites...
January 10, 2018: Journal of Leukocyte Biology
Yingming Sun, Hongtao Miao, Shijing Ma, Lei Zhang, Chengcheng You, Fang Tang, Cui Yang, Xiaoli Tian, Feng Wang, Yuan Luo, Xiangjie Lin, Hui Wang, Chunyang Li, Zhijun Li, Hongnv Yu, Xuefeng Liu, Yu Xiao, Yan Gong, Junhong Zhang, Hong Quan, Conghua Xie
FePt-Cys nanoparticles (FePt-Cys NPs) have been well used in many fields, despite their poor solubility and stability. We synthetized a cysteine surface modified FePt NPs, which exhibited good solubility, stability and biocompatibility. We explored the insight mechanisms of the antitumor effects of this new nanoparticle system in lung cancer cells. In the in vitro study, FePt-Cys NPs induced a reactive oxygen species (ROS) burst, which suppressed the antioxidant protein expression and induced cell apoptosis...
January 10, 2018: Cancer Letters
Patrick E MacDonald
Post-translational modification of proteins contributes to the control of cell function and survival. The balance of these in insulin-producing pancreatic beta cells is important for the maintenance of glucose homeostasis. Protection from the damaging effects of reactive oxygen species is required for beta cell survival, but if this happens at the expense of insulin secretory function then the ability of islets to respond to changing metabolic conditions may be compromised. In this issue of Diabetologia, He et al ( https://doi...
January 12, 2018: Diabetologia
Ping-Ching Wu, Hua-Han Chen, Shih-Yao Chen, Wen-Lung Wang, Kun-Lin Yang, Chia-Hung Huang, Hui-Fang Kao, Jui-Cheng Chang, Chih-Li Lilian Hsu, Jiu-Yao Wang, Ting-Mao Chou, Wen-Shuo Kuo
BACKGROUND: The results showed that the deciding factor is the culture medium in which the bacteria and the graphene oxide (GO) are incubated at the initial manipulation step. These findings allow better use of GO and GO-based materials more and be able to clearly apply them in the field of biomedical nanotechnology. RESULTS: To study the use of GO sheets applied in the field of biomedical nanotechnology, this study determines whether GO-based materials [GO, GO-polyoxyalkyleneamine (POAA), and GO-chitosan] stimulate or inhibit bacterial growth in detail...
January 10, 2018: Journal of Nanobiotechnology
Joakim Halldin Stenlid, Adam Johannes Johansson, Tore Brinck
Using local DFT-based probes for electrostatic as well as charge transfer/polarization interactions, we are able to characterize Lewis basic and acidic sites on copper, silver and gold nanoparticles. The predictions obtained using the DFT-probes are compared to the interaction energies of the electron donating (CO, H2O, NH3 and H2S) and the electron accepting (BH3, BF3, HCl [H-down] and Na+) compounds. The probes include the local electron attachment energy [E(r)], the average local ionization energy [Ī(r)], and the electrostatic potential [V(r)] and are evaluated on isodensity surfaces located at distances corresponding to typical interaction distances...
January 10, 2018: Physical Chemistry Chemical Physics: PCCP
Shiho Sairenji, Shigehisa Akine, Tatsuya Nabeshima
In biological systems, there are many signal transduction cascades in which a chemical signal is transferred as a series of chemical events. Such successive reaction systems are advantageous because the efficiency of the functions can be finely controlled by regulatory enzymes at an earlier stage. However, most of artificial responsive molecules developed so far rely on single-step conversion, whose response speeds have been difficult to be controlled by external stimuli. In this context, developing artificial conversion systems that have a regulation step similar to the regulatory enzymes has been anticipated...
January 9, 2018: Scientific Reports
Xiaokang Lv, Tingting Li, Qinghua Wu, Changjiang Yu, Lijuan Jiao, Erhong Hao
A series of mono- to hexa-brominated BOPHY dyes have been regioselectively synthesized in 41%-96% yields from bromination of parent BOPHY, bromination of hydrazine linked bispyrrole intermediate, or brominated 2-formylpyrrole precursors in moderate to excellent yields. The reactivities of these polybrominated BOPHY dyes were further studied via regioselective nucleophilic substitution or Suzuki/Stille cross-coupling reactions, from which a series of 5- or 5,5'-substituted BOPHYs with various nucleophiles such as amine, pyrrole, thiophene and phenyl groups were obtained in moderate to high yields of 37%-94%...
January 9, 2018: Journal of Organic Chemistry
Qing Lv, Baogang Zhang, Xuan Xing, Yingxin Zhao, Ruquan Cai, Wei Wang, Qian Gu
Metallic nanoparticle based disinfection represents a promising approach for microbial pollution control in drinking water and thus, biosynthesis of non precious metal nanoparticles is of considerable interest. Herein, an original and efficient route for directly microbial synthesis of copper nanoparticles (Cu-NPs) by Shewanella loihica PV-4 is described and their satisfactorily antimicrobial activities are established. Cu-NPs were successfully synthesized and most of them attaching on the bacterial cell surfaces suggested extracellular Cu(II) bioreduction mainly contributed to this biosynthesis...
December 29, 2017: Journal of Hazardous Materials
Masakazu Kanematsu, Glenn Waychunas, Jean-François Boily
Silica-bearing waters in nature often alter the reactivity of mineral surfaces via deposition of Si complexes and solids. In this work, Fourier transform infrared (FTIR) spectroscopy was used to identify hydroxo groups at goethite (-FeOOH) and lepidocrocite (-FeOOH) surfaces that are targeted by ligand exchange reactions with monomeric silicate species. Measurements of samples first reacted in aqueous solutions then dried under N2(g) enabled resolution of the signature O-H stretching bands of singly (OH), doubly- (μ-OH) and triply-coordinated (μ3-OH)...
January 5, 2018: Environmental Science & Technology
V Fasano, J H W LaFortune, J M Bayne, M J Ingleson, D W Stephan
A new class of electrophilic phosphonium cations (EPCs) containing a -CF3 group attached to the phosphorus(v) center is readily accessible in high yields, via a scalable process. These species are stable to air, water, alcohol and strong Brønsted acid, even at raised temperatures. Thus, P-CF3 EPCs are more robust than previously reported EPCs containing P-X moieties (X = F, Cl, OR), and despite their reduced Lewis acidity they function as Lewis acid catalysts without requiring anhydrous reaction conditions...
January 5, 2018: Chemical Communications: Chem Comm
Ramonita Díaz-Ayala, Lisa Torres-González, Ruth Pietri, Carlos R Cabrera, Juan López-Garriga
The recombinant HbI was fused with a poly-Lys tag ((Lys)6-tagged rHbI) for specific-site covalent immobilization on two carbon nanotube transducer surfaces, i.e., powder and vertically aligned carbon nanotubes. The immobilization was achieved by following two steps: (1) generation of amine-reactive ester from the carboxylic acid groups of the surfaces and (2) coupling these groups with the amine groups of the Lys-tag. We analyzed the immobilization process using different conditions and techniques to differentiate protein covalent attachment from physical adsorption...
December 31, 2017: ACS Omega
Danish Hussain, Yongbing Wen, Hao Zhang, Jianmin Song, Hui Xie
Sidewall roughness measurement is becoming increasingly important in the micro-electromechanical systems and nanoelectronics devices. Atomic force microscopy (AFM) is an emerging technique for sidewall scanning and roughness measurement due to its high resolution, three-dimensional imaging capability and high accuracy. We report an AFM sidewall imaging method with a quartz tuning fork (QTF) force sensor. A self sensing and actuating force sensor is fabricated by microassembling a commercial AFM cantilever (tip apex radius ≤10 nm) to a QTF...
January 1, 2018: Sensors
Xiaoyu He, Qiaohong Lai, Cai Chen, Na Li, Fei Sun, Wenting Huang, Shu Zhang, Qilin Yu, Ping Yang, Fei Xiong, Zhishui Chen, Quan Gong, Boxu Ren, Jianping Weng, Décio L Eizirik, Zhiguang Zhou, Cong-Yi Wang
AIMS/HYPOTHESIS: Post-translational attachment of a small ubiquitin-like modifier (SUMO) to the lysine (K) residue(s) of target proteins (SUMOylation) is an evolutionary conserved regulatory mechanism. This modification has previously been demonstrated to be implicated in the control of a remarkably versatile regulatory mechanism of cellular processes. However, the exact regulatory role and biological actions of the E2 SUMO-conjugating enzyme (UBC9)-mediated SUMOylation function in pancreatic beta cells has remained elusive...
January 3, 2018: Diabetologia
Boknam Jung, Jungwook Park, Namgyu Kim, Taiying Li, Soyeon Kim, Laura E Bartley, Jinnyun Kim, Inyoung Kim, Yoonhee Kang, Kihoon Yun, Younghae Choi, Hyun-Hee Lee, Sungyeon Ji, Kwang Sik Lee, Bo Yeon Kim, Jong Cheol Shon, Won Cheol Kim, Kwang-Hyeon Liu, Dahye Yoon, Suhkman Kim, Young-Su Seo, Jungkwan Lee
Bacterial-fungal interactions are widely found in distinct environments and contribute to ecosystem processes. Previous studies of these interactions have mostly been performed in soil, and only limited studies of aerial plant tissues have been conducted. Here we show that a seed-borne plant pathogenic bacterium, Burkholderia glumae (Bg), and an air-borne plant pathogenic fungus, Fusarium graminearum (Fg), interact to promote bacterial survival, bacterial and fungal dispersal, and disease progression on rice plants, despite the production of antifungal toxoflavin by Bg...
January 2, 2018: Nature Communications
Tayo Alex Adekiya, Raphael Taiwo Aruleba, Sbonelo Khanyile, Priscilla Masamba, Babatunji Emmanuel Oyinloye, Abidemi Paul Kappo
Major histocompatibility complex class 1 chain-related gene sequence A is a polymorphic gene found at about 46.6 kb centromeric to HLA-B. It encodes a transmembrane protein, which is a non-classical human leukocyte antigen whose expression is normally induced by stress conditions like cancer and viral infections. The expression of MIC-A leads to the activation of NKG2D receptors of natural killer and T cells, leading to the generation of innate immune response that can easily eliminate/cleanse tumour cells and other cells that express the protein...
December 25, 2017: Vaccines
Devaraj Manoj, K Theyagarajan, Duraisamy Saravanakumar, Sellappan Senthilkumar, Kathavarayan Thenmozhi
An aldehyde functionalized ionic liquid, (3-(3-formyl-4-hydroxybenzyl)-3-methylimidazolium hexafluorophosphate) (CHO-IL) has been employed herein as a multiple host platform for the covalent immobilization of mediator as well as enzyme. The CHO-IL was immobilized on electrochemically reduced graphene oxide (ERGO) through the π-π stacking of hydroxybenzyl and imidazolium groups with ERGO and subjected to further covalent attachment of Azure A (Azu-A) mediator or glucose oxidase (GOx) enzyme. Electroactive, water soluble organic dye Azu-A was effectively immobilized to the host IL through simple Schiff base reaction...
December 21, 2017: Biosensors & Bioelectronics
Shangwei Zhang, Lorenz Adrian, Gerrit Schüürmann
The bacterium Dehalococcoides, strain CBDB1, transforms aromatic halides through reductive dehalogenation. So far, however, the structures of its vitamin B12-containing dehalogenases are unknown, hampering clarification of the catalytic mechanism and substrate specificity as basis for targeted remediation strategies. This study employs a quantum chemical donor-acceptor approach for the Co(I)-substrate electron transfer. Computational characterization of the substrate electron affinity at carbon-halogen bonds enables discriminating aromatic halides ready for dehalogenation by strain CBDB1 (active substrates) from non-dehalogenated (inactive) counterparts with 92% accuracy, covering 86 of 93 bromobenzenes, chlorobenzenes, chlorophenols, chloroanilines, polychlorinated biphenyls, and dibenzo-p-dioxins...
December 28, 2017: Environmental Science & Technology
Melanie J Blanden, Kiall F Suazo, Emily R Hildebrandt, Daniel S Hardgrove, Meet Patel, William P Saunders, Mark D Distefano, Walter K Schmidt, James L Hougland
Protein prenylation is a post-translational modification that has been most commonly associated with enabling protein trafficking to and interaction with cellular membranes. In this process, an isoprenoid group is attached to a cysteine near the C-terminus of a substrate protein by protein farnesyltransferase (FTase) or protein geranylgeranyltransferase type I or II (GGTase-I and GGTase-II). FTase and GGTase-I have long been proposed to specifically recognize a four amino acid CaaX C-terminal sequence within their substrates...
December 27, 2017: Journal of Biological Chemistry
Eric E Benson, Hanyu Zhang, Samuel A Schuman, Sanjini U Nanayakkara, Noah D Bronstein, Suzanne Ferrere, Jeffrey L Blackburn, Elisa M Miller
We modify the fundamental electronic properties of metallic (1T phase) nanosheets of molybdenum disulfide (MoS2) through covalent chemical functionalization, and thereby directly influence the kinetics of the hydrogen evolution reaction (HER), surface energetics, and stability. Chemically exfoliated, metallic MoS2 nanosheets are functionalized with organic phenyl rings containing electron donating or withdrawing groups. We find that MoS2 functionalized with the most electron donating functional group (p-(CH3CH2)2NPh-MoS2) is the most efficient catalyst for HER in this series, with initial activity that is slightly worse compared to the pristine metallic phase of MoS2...
December 27, 2017: Journal of the American Chemical Society
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