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Alexandra Ioana Lupulescu, Wei Qin, Jeffrey D Rimer
Nonclassical mechanisms of crystal growth often involve the formation of amorphous precursors that play a direct role in what is generally referred to as crystallization by particle attachment (or CPA). One of the most studied CPA systems in literature is zeolite MFI, which is a microporous crystal with siliceous (silicalite-1) and aluminosilicate (ZSM-5) isostructures. The self-assembly, microstructural evolution, and mechanistic role of nanoparticle precursors (1 - 6 nm) during silicalite-1 crystallization have been the subjects of prior investigation by combined experimental and modeling techniques...
October 17, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Suhee Song, Joonhee Lee, Songa Kweon, Jaeeun Song, Kyuseok Kim, Byeong-Su Kim
Functional hyperbranched polyglycerols (PGs) have recently garnered considerable interest due to their potential in biomedical applications. Here, we present a one-pot synthesis of hyperbranched PGs possessing amine functionality using a novel amino glycidyl ether monomer. A Boc-protected butanolamine glycidyl ether (BBAG) monomer was designed and polymerized with glycidol (G) through anionic ring-opening multibranching polymerization to yield a series of hyperbranched P(G-co-BBAG) with controlled molecular weights (4800-16700 g/mol) and relatively low molecular weight distributions (1...
October 14, 2016: Biomacromolecules
Jordi Mayneris-Perxachs, David T Bolick, Joy Leng, Greg L Medlock, Glynis L Kolling, Jason A Papin, Jonathan R Swann, Richard L Guerrant
BACKGROUND: Environmental enteropathy, which is linked to undernutrition and chronic infections, affects the physical and mental growth of children in developing areas worldwide. Key to understanding how these factors combine to shape developmental outcomes is to first understand the effects of nutritional deficiencies on the mammalian system including the effect on the gut microbiota. OBJECTIVE: We dissected the nutritional components of environmental enteropathy by analyzing the specific metabolic and gut-microbiota changes that occur in weaned-mouse models of zinc or protein deficiency compared with well-nourished controls...
October 12, 2016: American Journal of Clinical Nutrition
Yan Xu, Jie Chen, Lan Xiao, Hee Kyoung Chung, Yuan Zhang, Joseph C Robinson, Jaladanki N Rao, Jian-Ying Wang
The RNA-binding protein HuR is crucial for normal intestinal mucosal regeneration by modulating the stability and translation of target mRNAs, but the exact mechanism underlying HuR trafficking between the cytoplasm and nucleus remains largely unknown. Here we report a novel function of transcription factor JunD in the regulation of HuR subcellular localization through the control of importin-α1 expression in intestinal epithelial cells (IECs). Ectopically expressed JunD specifically inhibited importin-α1 at the transcription level, and this repression is mediated via interaction with CREB-binding site that was located at the proximal region of importin-α1 promoter...
October 12, 2016: American Journal of Physiology. Cell Physiology
Caroline H Johnson, Mary E Spilker, Laura Goetz, Scott N Peterson, Gary Siuzdak
The role of the host microbiome has come to the forefront as a potential modulator of cancer metabolism and could be a future target for precision medicine. A recent study revealed that in colon cancer, bacteria form polysaccharide matrices called biofilms at a high frequency in the proximal colon. Comprehensive untargeted and stable isotope-assisted metabolomic analysis revealed that the bacteria utilize polyamine metabolites produced from colon adenomas/carcinomas to build these protective biofilms and may contribute to inflammation and proliferation observed in colon cancer...
October 11, 2016: Cancer Research
Verónica Seguel, Lorena Castro, Chantal Reigada, Leonel Cortes, María V Díaz, Mariana R Miranda, Claudio A Pereira, Michel Lapier, Carolina Campos-Estrada, Antonio Morello, Ulrike Kemmerling, Juan D Maya, Rodrigo López-Muñoz
Benznidazole is the first-line drug used in treating Chagas disease, which is caused by the parasite Trypanosoma cruzi (T. cruzi). However, benznidazole has limited efficacy and several adverse reactions. Pentamidine is an antiprotozoal drug used in the treatment of leishmaniasis and African trypanosomiasis. In T. cruzi, pentamidine blocks the transport of putrescine, a precursor of trypanothione, which constitutes an essential molecule in the resistance of T. cruzi to benznidazole. In the present study, we describe the effect of the combination of benznidazole and pentamidine on isolated parasites, mammalian cells and in mice infected with T...
October 8, 2016: Experimental Parasitology
Adel Zarei, Christopher P Trobacher, Barry J Shelp
Polyamines represent a potential source of 4-aminobutyrate (GABA) in plants exposed to abiotic stress. Terminal catabolism of putrescine in Arabidopsis thaliana involves amine oxidase and the production of 4-aminobutanal, which is a substrate for NAD(+)-dependent aminoaldehyde dehydrogenase (AMADH). Here, two AMADH homologs were chosen (AtALDH10A8 and AtALDH10A9) as candidates for encoding 4-aminobutanal dehydrogenase activity for GABA synthesis. The two genes were cloned and soluble recombinant proteins were produced in Escherichia coli...
October 11, 2016: Scientific Reports
Selina Schimka, Nino Lomadze, Maren Rabe, Alexey Kopyshev, Maren Lehmann, Regine von Klitzing, Artem M Rumyantsev, Elena Yu Kramarenko, Svetlana Santer
We report on light sensitive microgel particles that can change their volume reversibly in response to illumination with light of different wavelengths. To make the anionic microgels photosensitive we add surfactants with a positively charged polyamine head group and an azobenzene containing tail. Upon illumination, azobenzene undergoes a reversible photo-isomerization reaction from a trans- to a cis-state accompanied by a change in the hydrophobicity of the surfactant. Depending on the isomerization state, the surfactant molecules are either accommodated within the microgel (trans-state) resulting in its shrinkage or desorbed back into water (cis-isomer) letting the microgel swell...
October 10, 2016: Physical Chemistry Chemical Physics: PCCP
Qiang Zhang, Yong Yan, Ge Chen
A green and simple biomineralization-inspired method to create "net"-like interconnected TiO2 nanoparticles conformably covering reduced graphene oxide (RGO) with high loading density is reported. This method uses polyamine as both the biomineralization agent and linker to manipulate the nucleation, growth, and crystallization of TiO2 nanoparticles on the surface of graphene oxide. The obtained TiO2/RGO composites demonstrate sub-10-nm TiO2 nanoparticles with (001) facets, ultrathin thickness (10-12 nm), and a high surface area of 172 m(2) g(-1)...
November 2015: Advanced Science (Weinheim, Baden-Wurttemberg, Germany)
Nicolas Coudray, Sean Seyler, Ralph Lasala, Zhening Zhang, Kathy M Clark, Mark E Dumont, Alexis Rohou, Oliver Beckstein, David L Stokes
Bor1p is a secondary transporter in yeast that is responsible for boron transport. Bor1p belongs to the SLC4 family which controls in bicarbonate exchange and pH regulation in animals as well as borate uptake in plants. The SLC4 family is more distantly related to members of the Amino acid-Polyamine-organoCation (APC) superfamily, which includes well studied transporters such as LeuT, Mhp1, AdiC, vSGLT, UraA, SLC26Dg. Their mechanism generally involve relative movements of two domains: a core domain that binds substrate and a gate domain that in many cases mediates dimerization...
October 7, 2016: Protein Science: a Publication of the Protein Society
Rucha Harishbhai Mehta, Manivel Ponnuchamy, Jitendra Kumar, Nagaraja Reddy Rama Reddy
De novo assembly of reads produced by next-generation sequencing (NGS) technologies offers a rapid approach to obtain expressed gene sequences for non-model organisms. Senna (Cassia angustifolia Vahl.) is a drought-tolerant annual undershrub of Caesalpiniaceae, a subfamily of Fabaceae. There are insufficient transcriptomic and genomic data in public databases for understanding the molecular mechanism underlying the drought tolerance of senna. Therefore, the main purpose of this study was to know the transcriptome profile of senna, with special reference to drought stress...
October 5, 2016: Functional & Integrative Genomics
Yang Ou, Shang-Jui Wang, Dawei Li, Bo Chu, Wei Gu
Although p53-mediated cell-cycle arrest, senescence, and apoptosis remain critical barriers to cancer development, the emerging role of p53 in cell metabolism, oxidative responses, and ferroptotic cell death has been a topic of great interest. Nevertheless, it is unclear how p53 orchestrates its activities in multiple metabolic pathways into tumor suppressive effects. Here, we identified the SAT1 (spermidine/spermine N(1)-acetyltransferase 1) gene as a transcription target of p53. SAT1 is a rate-limiting enzyme in polyamine catabolism critically involved in the conversion of spermidine and spermine back to putrescine...
October 3, 2016: Proceedings of the National Academy of Sciences of the United States of America
G Díaz-Soto, A Rocher, C García-Rodríguez, L Núñez, C Villalobos
The extracellular calcium-sensing receptor (CaSR) is a unique G protein-coupled receptor (GPCR) activated by extracellular Ca(2+) and by other physiological cations including Mg(2+), amino acids, and polyamines. CaSR is the most important master controller of the extracellular Ca(2+) homeostatic system being expressed at high levels in the parathyroid gland, kidney, gut and bone, where it regulates parathyroid hormone (PTH) secretion, vitamin D synthesis, and Ca(2+) absorption and resorption, respectively. Gain and loss of function mutations in the CaSR are responsible for severe disturbances in extracellular Ca(2+) metabolism...
2016: International Review of Cell and Molecular Biology
Ayesha Kabir, Devawati Dutta, Chhabinath Mandal, Gopinatha Suresh Kumar
A major thrust of anticancer therapeutics is the dynamic quest for small molecules that binds and modifies nucleic acids and proteins effectively. The role of tRNA in the protein translational machinery and the influence of polyamines on the interaction of acylated and deacylated tRNA to ribosomes,47-48 make polyamine-tRNA interactions conspicuous. Therefore, we have studied the interaction of two biogenic polyamines spermine and spermidine with tRNAPhe and compared the interaction with the polyamine analog, 1-naphthyl acetyl spermine to fathom the thermodynamic and structural basis of the binding interaction...
October 3, 2016: Journal of Physical Chemistry. B
Alain P Gobert, Keith T Wilson
Helicobacter pylori is a Gram-negative bacterium that specifically colonizes the gastric ecological niche. During the infectious process, which results in diseases ranging from chronic gastritis to gastric cancer, the host response is characterized by the activation of the innate immunity of gastric epithelial cells and macrophages. These cells thus produce effector molecules such as reactive oxygen species (ROS) to counteract the infection. The generation of ROS in response to H. pylori involves two canonical pathways: 1) the NADPH-dependent reduction of molecular oxygen to generate O2(•-), which can dismute to generate ROS; and 2) the back-conversion of the polyamine spermine into spermidine through the enzyme spermine oxidase, leading to H2O2 production...
September 25, 2016: Free Radical Biology & Medicine
Steven D Aird, Alejandro Villar Briones, Michael C Roy, Alexander S Mikheyev
While decades of research have focused on snake venom proteins, far less attention has been paid to small organic venom constituents. Using mostly pooled samples, we surveyed 31 venoms (six elapid, six viperid, and 19 crotalid) for spermine, spermidine, putrescine, and cadaverine. Most venoms contained all four polyamines, although some in essentially trace quantities. Spermine is a potentially significant component of many viperid and crotalid venoms (≤0.16% by mass, or 7.9 µmol/g); however, it is almost completely absent from elapid venoms assayed...
2016: Toxins
Tracy R Murray-Stewart, Patrick M Woster, Robert A Casero
The chemically simple, biologically complex eukaryotic polyamines, spermidine and spermine, are positively charged alkylamines involved in many crucial cellular processes. Along with their diamine precursor putrescine, their normally high intracellular concentrations require fine attenuation by multiple regulatory mechanisms to keep these essential molecules within strict physiologic ranges. Since the metabolism of and requirement for polyamines are frequently dysregulated in neoplastic disease, the metabolic pathway and functions of polyamines provide rational drug targets; however, these targets have been difficult to exploit for chemotherapy...
October 1, 2016: Biochemical Journal
Yesseinia I Angleró-Rodríguez, Benjamin J Blumberg, Yuemei Dong, Simone L Sandiford, Andrew Pike, April M Clayton, George Dimopoulos
Whereas studies have extensively examined the ability of bacteria to influence Plasmodium infection in the mosquito, the tripartite interactions between non-entomopathogenic fungi, mosquitoes, and Plasmodium parasites remain largely uncharacterized. Here we report the isolation of a common mosquito-associated ascomycete fungus, Penicillium chrysogenum, from the midgut of field-caught Anopheles mosquitoes. Although the presence of Pe. chrysogenum in the Anopheles gambiae midgut does not affect mosquito survival, it renders the mosquito significantly more susceptible to Plasmodium infection through a secreted heat-stable factor...
September 28, 2016: Scientific Reports
Enzo Agostinelli
No abstract text is available yet for this article.
October 2016: Amino Acids
Anastasia Shebanova, Tatiana Ismagulova, Alexei Solovchenko, Olga Baulina, Elena Lobakova, Alexandra Ivanova, Andrey Moiseenko, Konstantin Shaitan, Vladimir Polshakov, Ladislav Nedbal, Olga Gorelova
Vacuole is a multifunctional compartment central to a large number of functions (storage, catabolism, maintenance of the cell homeostasis) in oxygenic phototrophs including microalgae. Still, microalgal cell vacuole is much less studied than that of higher plants although knowledge of the vacuolar structure and function is essential for understanding physiology of nutrition and stress tolerance of microalgae. Here, we combined the advanced analytical and conventional transmission electron microscopy methods to obtain semi-quantitative, spatially resolved at the subcellular level information on elemental composition of the cell vacuoles in several free-living and symbiotic chlorophytes...
September 27, 2016: Protoplasma
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