International Journal of Molecular Sciences

292 KiB

Open AccessArticle

Fructose Production by Inulinase Covalently Immobilized on Sepabeads in Batch and Fluidized Bed Bioreactor

by Emanuele Ricca, Vincenza Calabrò, Stefano Curcio, Alessandra Basso, Lucia Gardossi and Gabriele Iorio

Int. J. Mol. Sci. 2010, 11(3), 1180-1189; https://doi.org/10.3390/ijms11031180 - 19 Mar 2010

Cited by 31 | Viewed by 15019

Abstract

The present work is an experimental study of the performance of a recently designed immobilized enzyme: inulinase from Aspergillus sp. covalently immobilized on Sepabeads. The aim of the work is to test the new biocatalyst in conditions of industrial interest and to assess [...] Read more.

The present work is an experimental study of the performance of a recently designed immobilized enzyme: inulinase from Aspergillus sp. covalently immobilized on Sepabeads. The aim of the work is to test the new biocatalyst in conditions of industrial interest and to assess the feasibility of the process in a fluidized bed bioreactor (FBBR). The catalyst was first tested in a batch reactor at standard conditions and in various sets of conditions of interest for the process. Once the response of the catalyst to different operating conditions was tested and the operational stability assessed, one of the sets of conditions tested in batch was chosen for tests in FBBR. Prior to reaction tests, preliminary fluidization tests were realized in order to define an operating range of admissible flow rates. As a result, the FBR was run at different feed flow rates in a closed cycle configuration and its performance was compared to that of the batch system. The FBBR proved to be performing and suitable for scale up to large fructose production. Full article

(This article belongs to the Special Issue Biocatalysis)

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2207 KiB

Open AccessArticle

Monolayer-directed Assembly and Magnetic Properties of FePt Nanoparticles on Patterned Aluminum Oxide

by Oktay Yildirim, Tian Gang, Sachin Kinge, David N. Reinhoudt, Dave H. A. Blank, Wilfred G. Van der Wiel, Guus Rijnders and Jurriaan Huskens

Int. J. Mol. Sci. 2010, 11(3), 1162-1179; https://doi.org/10.3390/iijms11031162 - 19 Mar 2010

Cited by 18 | Viewed by 20188

Abstract

FePt nanoparticles (NPs) were assembled on aluminum oxide substrates, and their ferromagnetic properties were studied before and after thermal annealing. For the first time, phosph(on)ates were used as an adsorbate to form self-assembled monolayers (SAMs) on alumina to direct the assembly of NPs [...] Read more.

FePt nanoparticles (NPs) were assembled on aluminum oxide substrates, and their ferromagnetic properties were studied before and after thermal annealing. For the first time, phosph(on)ates were used as an adsorbate to form self-assembled monolayers (SAMs) on alumina to direct the assembly of NPs onto the surface. The Al₂O₃ substrates were functionalized with aminobutylphosphonic acid (ABP) or phosphonoundecanoic acid (PNDA) SAMs or with poly(ethyleneimine) (PEI) as a reference. FePt NPs assembled on all of these monolayers, but much less on unmodified Al₂O₃, which shows that ligand exchange at the NPs is the most likely mechanism of attachment. Proper modification of the Al₂O₃ surface and controlling the immersion time of the modified Al₂O₃ substrates into the FePt NP solution resulted in FePt NPs assembly with controlled NP density. Alumina substrates were patterned by microcontact printing using aminobutylphosphonic acid as the ink, allowing local NP assembly. Thermal annealing under reducing conditions (96%N₂/4%H₂) led to a phase change of the FePt NPs from the disordered FCC phase to the ordered FCT phase. This resulted in ferromagnetic behavior at room temperature. Such a process can potentially be applied in the fabrication of spintronic devices. Full article

(This article belongs to the Special Issue Molecular Self-Assembly)

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272 KiB

Open AccessArticle

Characteristics of Lipo-Oligosaccharide Loci of Campylobacter jejuni Isolates Associated with Guillain-Barré Syndrome from Hebei, China

by Hai Jiang, Mao-Jun Zhang, Rui-Chun Liu, Xin-Ying Tian, Yi-Xin Gu and Jian-Zhong Zhang

Int. J. Mol. Sci. 2010, 11(3), 1155-1161; https://doi.org/10.3390/ijms11031155 - 19 Mar 2010

Cited by 4 | Viewed by 12300

Abstract

Ganglioside mimicry by C. jejuni lipo-oligosaccharides (LOS) could induce the production of autoantibodies against gangliosides and the development of Guillain-Barré syndrome (GBS). The LOS biosynthesis region exhibits significant variation with different strains. Using PCR amplifications of genes from published LOS loci and sequencing [...] Read more.

Ganglioside mimicry by C. jejuni lipo-oligosaccharides (LOS) could induce the production of autoantibodies against gangliosides and the development of Guillain-Barré syndrome (GBS). The LOS biosynthesis region exhibits significant variation with different strains. Using PCR amplifications of genes from published LOS loci and sequencing the LOS biosynthesis loci, the eight GBS-associated C. jejuni strains from HeBei could be classified into four classes. The expression of sialylated LOS structures (class A) or non-sialylated LOS structures(class F, H and P) in the C. jejuni LOS is considered to be two different factors for the induction of GBS. Full article

(This article belongs to the Section Biochemistry)

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607 KiB

Open AccessArticle

Proper Distance Metrics for Phylogenetic Analysis Using Complete Genomes without Sequence Alignment

by Zu-Guo Yu, Xiao-Wen Zhan, Guo-Sheng Han, Roger W. Wang, Vo Anh and Ka Hou Chu

Int. J. Mol. Sci. 2010, 11(3), 1141-1154; https://doi.org/10.3390/ijms11031141 - 18 Mar 2010

Cited by 23 | Viewed by 11289

Abstract

A shortcoming of most correlation distance methods based on the composition vectors without alignment developed for phylogenetic analysis using complete genomes is that the “distances” are not proper distance metrics in the strict mathematical sense. In this paper we propose two new correlation-related [...] Read more.

A shortcoming of most correlation distance methods based on the composition vectors without alignment developed for phylogenetic analysis using complete genomes is that the “distances” are not proper distance metrics in the strict mathematical sense. In this paper we propose two new correlation-related distance metrics to replace the old one in our dynamical language approach. Four genome datasets are employed to evaluate the effects of this replacement from a biological point of view. We find that the two proper distance metrics yield trees with the same or similar topologies as/to those using the old “distance” and agree with the tree of life based on 16S rRNA in a majority of the basic branches. Hence the two proper correlation-related distance metrics proposed here improve our dynamical language approach for phylogenetic analysis. Full article

(This article belongs to the Special Issue Cladistic Analysis and Molecular Evolution)

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884 KiB

Open AccessArticle

Comparative Study of the Dissociative Ionization of 1,1,1 Trichloroethane Using Nanosecond and Femtosecond Laser Pulses

by Anton Du Plessis, Christien Strydom and Lourens Botha

Int. J. Mol. Sci. 2010, 11(3), 1114-1140; https://doi.org/10.3390/ijms11031114 - 17 Mar 2010

Cited by 2 | Viewed by 12367

Abstract

Changes in the laser induced molecular dissociation of 1,1,1-trichloroethane (TCE) were studied using a range of intensities and standard laser wavelengths with nanosecond and femtosecond pulse durations. TCE contains C-H, C-C and C-Cl bonds and selective bond breakage of one or more of [...] Read more.

Changes in the laser induced molecular dissociation of 1,1,1-trichloroethane (TCE) were studied using a range of intensities and standard laser wavelengths with nanosecond and femtosecond pulse durations. TCE contains C-H, C-C and C-Cl bonds and selective bond breakage of one or more of these bonds is of scientific interest. Using laser ionization time of flight mass spectrometry, it was found that considerable variation of fragment ion peak heights as well as changes in relative peak ratios is possible by varying the laser intensity (by attenuation), wavelength and pulse duration using standard laser sources. The nanosecond laser dissociation seems to occur via C-Cl bond breakage, with significant fragmentation and only a few large mass ion peaks observed. In contrast, femtosecond laser dissociative ionization results in many large mass ion peaks. Evidence is found for various competing dissociation and ionization pathways. Variation of the nanosecond laser intensity does not change the fragmentation pattern, while at high femtosecond intensities large changes are observed in relative ion peak sizes. The total ionization yield and fragmentation ratios are presented for a range of wavelengths and intensities, and compared to the changes observed due to a linear chirp variation. Full article

(This article belongs to the Section Physical Chemistry, Theoretical and Computational Chemistry)

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Graphical abstract

217 KiB

Open AccessReview

Dye Sensitized Solar Cells

by Di Wei

Int. J. Mol. Sci. 2010, 11(3), 1103-1113; https://doi.org/10.3390/ijms11031103 - 16 Mar 2010

Cited by 219 | Viewed by 33289

Abstract

Dye sensitized solar cell (DSSC) is the only solar cell that can offer both the flexibility and transparency. Its efficiency is comparable to amorphous silicon solar cells but with a much lower cost. This review not only covers the fundamentals of DSSC but [...] Read more.

Dye sensitized solar cell (DSSC) is the only solar cell that can offer both the flexibility and transparency. Its efficiency is comparable to amorphous silicon solar cells but with a much lower cost. This review not only covers the fundamentals of DSSC but also the related cutting-edge research and its development for industrial applications. Most recent research topics on DSSC, for example, applications of nanostructured TiO₂, ZnO electrodes, ionic liquid electrolytes, carbon nanotubes, graphene and solid state DSSC have all been included and discussed. Full article

(This article belongs to the Section Biochemistry)

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423 KiB

Open AccessArticle

Evolutionary Divergence of Duplicate Copies of the Growth Hormone Gene in Suckers (Actinopterygii: Catostomidae)

by Henry L. Bart, Jr., Paulette C. Reneau, Michael H. Doosey and Charles D. Bell

Int. J. Mol. Sci. 2010, 11(3), 1090-1102; https://doi.org/10.3390/ijms11031090 - 16 Mar 2010

Cited by 20 | Viewed by 12625

Abstract

Catostomid fishes (suckers) have duplicate copies of the growth hormone gene and other nuclear genes, due to a genome duplication event early in the group’s history. Yet, paralogs of GH in suckers are more than 90% conserved in nucleotide (nt) and amino acid [...] Read more.

Catostomid fishes (suckers) have duplicate copies of the growth hormone gene and other nuclear genes, due to a genome duplication event early in the group’s history. Yet, paralogs of GH in suckers are more than 90% conserved in nucleotide (nt) and amino acid (aa) sequence. Within paralogs across species, variation in nt and aa sequence averages 3.33% and 4.46% for GHI, and 3.22% and 2.43% for GHII, respectively. Selection tests suggest that the two GH paralogs are under strong purifying selection. Consensus trees from phylogenetic analysis of GH coding region data for 23 species of suckers, other cypriniform fishes and outgroups resolved cypriniform relationships and relationships among GHI sequences of suckers more or less consistently with analyses based on other molecular data. However, the analysis failed to resolve all sucker GHI and GHII sequences as monophyletic sister groups. This unexpected topology did not differ significantly from topologies constrained to make all GH sequences monophyletic. We attribute this result either to limitations in our GHII data set or convergent adaptive changes in GHII of tribe Catostomini. Full article

(This article belongs to the Special Issue Cladistic Analysis and Molecular Evolution)

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468 KiB

Open AccessReview

Tyrosinase-Expressing Neuronal Cell Line as in Vitro Model of Parkinson’s Disease

by Takafumi Hasegawa

Int. J. Mol. Sci. 2010, 11(3), 1082-1089; https://doi.org/10.3390/ijms11031082 - 12 Mar 2010

Cited by 122 | Viewed by 18852

Abstract

Oxidized metabolites of dopamine known as dopamine quinone derivatives are thought to play a pivotal role in the degeneration of nigrostriatal dopaminergic neurons in Parkinson’s disease. Although such quinone derivatives are usually produced via the autoxidation of catecholamines, tyrosinase, which is a key [...] Read more.

Oxidized metabolites of dopamine known as dopamine quinone derivatives are thought to play a pivotal role in the degeneration of nigrostriatal dopaminergic neurons in Parkinson’s disease. Although such quinone derivatives are usually produced via the autoxidation of catecholamines, tyrosinase, which is a key enzyme in melanin biosynthesis via the production of DOPA and subsequent molecules, can potentially accelerate the induction of catecholamine quinone derivatives by its oxidase activity. We have developed neuronal cell lines in which the expression of human tyrosinase was inducible. Overexpression of tyrosinase resulted in increased intracellular dopamine content in association with the formation of melanin pigments in neuronal somata, which eventually causes apoptotic cell death. This cellular model will provide a useful tool for detailed analyses of the neurotoxicity of oxidized catechol metabolites. Full article

(This article belongs to the Special Issue Inhibitors of Melanogenesis Related Processes: Application to Food and Cosmetic Industry)

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224 KiB

Open AccessReview

Stem Cell Tracking by Nanotechnologies

by Chiara Villa, Silvia Erratico, Paola Razini, Fabrizio Fiori, Franco Rustichelli, Yvan Torrente and Marzia Belicchi

Int. J. Mol. Sci. 2010, 11(3), 1070-1081; https://doi.org/10.3390/ijms11031070 - 12 Mar 2010

Cited by 55 | Viewed by 18859

Abstract

Advances in stem cell research have provided important understanding of the cell biology and offered great promise for developing new strategies for tissue regeneration. The beneficial effects of stem cell therapy depend also by the development of new approachs for the track of [...] Read more.

Advances in stem cell research have provided important understanding of the cell biology and offered great promise for developing new strategies for tissue regeneration. The beneficial effects of stem cell therapy depend also by the development of new approachs for the track of stem cells in living subjects over time after transplantation. Recent developments in the use of nanotechnologies have contributed to advance of the high-resolution in vivo imaging methods, including positron emission tomography (PET), single-photon emission tomography (SPECT), magnetic resonance (MR) imaging, and X-Ray computed microtomography (microCT). This review examines the use of nanotechnologies for stem cell tracking. Full article

(This article belongs to the Special Issue Magnetic Nanoparticles)

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Graphical abstract

293 KiB

Open AccessArticle

Potential Effects of Chrysin on MDA-MB-231 Cells

by Teh Ban Hong, Anizah Rahumatullah, Thaneswary Yogarajah, Maimunah Ahmad and Khoo Boon Yin

Int. J. Mol. Sci. 2010, 11(3), 1057-1069; https://doi.org/10.3390/ijms11031057 - 11 Mar 2010

Cited by 34 | Viewed by 12193

Abstract

This study aims to elucidate the effects of chrysin on human ER-negative breast cancer cell line, MDA-MB-231. The study demonstrated that treatment of MDA-MB-231 cells with 20 µM chysin for 48 h significantly inhibited the growth of MDA-MB-231 cells and induced cytoplasmic [...] Read more.

This study aims to elucidate the effects of chrysin on human ER-negative breast cancer cell line, MDA-MB-231. The study demonstrated that treatment of MDA-MB-231 cells with 20 µM chysin for 48 h significantly inhibited the growth of MDA-MB-231 cells and induced cytoplasmic lipid accumulation in the cells, but that the observed of cell death was not caused by apoptosis. The expression of PPARalpha mRNA in chrysin-treated MDA-MB-231 cells was significantly increased, which was likely associated to the proliferation of the cells post chrysin treatment. Full article

(This article belongs to the Section Biochemistry)

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115 KiB

Open AccessArticle

Effect of Soybean Variety on Anti-Nutritional Factors Content, and Growth Performance and Nutrients Metabolism in Rat

by Chunmei Gu, Hongbin Pan, Zewei Sun and Guixin Qin

Int. J. Mol. Sci. 2010, 11(3), 1048-1056; https://doi.org/10.3390/ijms11031048 - 9 Mar 2010

Cited by 44 | Viewed by 14266

Abstract

The present study was undertaken to evaluate the effects of soybean varieties on content of anti-nutritional factors, growth, and nutrient digestibility in rat. For this purpose, the content of trypsin inhibitor and lectin was firstly measured in five soybean varieties. Then sixty male [...] Read more.

The present study was undertaken to evaluate the effects of soybean varieties on content of anti-nutritional factors, growth, and nutrient digestibility in rat. For this purpose, the content of trypsin inhibitor and lectin was firstly measured in five soybean varieties. Then sixty male Wistar rats were randomly divided into six groups and fed on different diets as follows: groups 1 to 5 were fed on treatment diets containing five different varieties of soybean flour; group 6 was fed on a control diet containing casein. All animals were fed for four weeks. During this period, faeces and urine were collected to determine the nutritional efficiency of diets and body weight were measured weekly on ten rats from each group. The results showed that trypsin inhibitor and lectin content of Jilin45 was the highest, and those of Jinong7 were the lowest of the soybean varieties. In comparison, all measured parameters, that is including gain in body weight, feed utilization efficiency, nutrient digestibility, nitrogen balance and nitrogen retention, were markedly different among the five groups of animals, but were significantly lower than the control group. These findings show that soybean varieties could significantly affect trypsin inhibitor and lectin content in soybean. Full article

(This article belongs to the Section Biochemistry)

359 KiB

Open AccessReview

A Review on Progress in QSPR Studies for Surfactants

by Jiwei Hu, Xiaoyi Zhang and Zhengwu Wang

Int. J. Mol. Sci. 2010, 11(3), 1020-1047; https://doi.org/10.3390/ijms11031020 - 8 Mar 2010

Cited by 81 | Viewed by 16053

Abstract

This paper presents a review on recent progress in quantitative structure-property relationship (QSPR) studies of surfactants and applications of various molecular descriptors. QSPR studies on critical micelle concentration (cmc) and surface tension (γ) of surfactants are introduced. Studies on charge distribution in ionic [...] Read more.

This paper presents a review on recent progress in quantitative structure-property relationship (QSPR) studies of surfactants and applications of various molecular descriptors. QSPR studies on critical micelle concentration (cmc) and surface tension (γ) of surfactants are introduced. Studies on charge distribution in ionic surfactants by quantum chemical calculations and its effects on the structures and properties of the colloids of surfactants are also reviewed. The trends of QSPR studies on cloud point (for nonionic surfactants), biodegradation potential and some other properties of surfactants are evaluated . Full article

(This article belongs to the Special Issue Recent Advances in QSAR/QSPR Theory)

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1221 KiB

Open AccessReview

Application of the Principles of Systems Biology and Wiener's Cybernetics for Analysis of Regulation of Energy Fluxes in Muscle Cells in Vivo

by Rita Guzun and Valdur Saks

Int. J. Mol. Sci. 2010, 11(3), 982-1019; https://doi.org/10.3390/ijms11030982 - 8 Mar 2010

Cited by 19 | Viewed by 17741

Abstract

The mechanisms of regulation of respiration and energy fluxes in the cells are analyzed based on the concepts of systems biology, non-equilibrium steady state kinetics and applications of Wiener’s cybernetic principles of feedback regulation. Under physiological conditions cardiac function is governed by the [...] Read more.

The mechanisms of regulation of respiration and energy fluxes in the cells are analyzed based on the concepts of systems biology, non-equilibrium steady state kinetics and applications of Wiener’s cybernetic principles of feedback regulation. Under physiological conditions cardiac function is governed by the Frank-Starling law and the main metabolic characteristic of cardiac muscle cells is metabolic homeostasis, when both workload and respiration rate can be changed manifold at constant intracellular level of phosphocreatine and ATP in the cells. This is not observed in skeletal muscles. Controversies in theoretical explanations of these observations are analyzed. Experimental studies of permeabilized fibers from human skeletal muscle vastus lateralis and adult rat cardiomyocytes showed that the respiration rate is always an apparent hyperbolic but not a sigmoid function of ADP concentration. It is our conclusion that realistic explanations of regulation of energy fluxes in muscle cells require systemic approaches including application of the feedback theory of Wiener’s cybernetics in combination with detailed experimental research. Such an analysis reveals the importance of limited permeability of mitochondrial outer membrane for ADP due to interactions of mitochondria with cytoskeleton resulting in quasi-linear dependence of respiration rate on amplitude of cyclic changes in cytoplasmic ADP concentrations. The system of compartmentalized creatine kinase (CK) isoenzymes functionally coupled to ANT and ATPases, and mitochondrial-cytoskeletal interactions separate energy fluxes (mass and energy transfer) from signalling (information transfer) within dissipative metabolic structures – intracellular energetic units (ICEU). Due to the non-equilibrium state of CK reactions, intracellular ATP utilization and mitochondrial ATP regeneration are interconnected by the PCr flux from mitochondria. The feedback regulation of respiration occurring via cyclic fluctuations of cytosolic ADP, Pi and Cr/PCr ensures metabolic stability necessary for normal function of cardiac cells. Full article

(This article belongs to the Special Issue Quantitative Modelling in Molecular System Bioenergetics)

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559 KiB

Open AccessCommunication

Robust Uptake of Magnetic Nanoparticles (MNPs) by Central Nervous System (CNS) Microglia: Implications for Particle Uptake in Mixed Neural Cell Populations

by Mark R. Pickard and Divya M. Chari

Int. J. Mol. Sci. 2010, 11(3), 967-981; https://doi.org/10.3390/ijms11030967 - 8 Mar 2010

Cited by 50 | Viewed by 12844

Abstract

Magnetic nanoparticles (MNPs) are important contrast agents used to monitor a range of neuropathological processes; microglial cells significantly contribute to MNP uptake in sites of pathology. Microglial activation occurs following most CNS pathologies but it is not known if such activation alters MNP [...] Read more.

Magnetic nanoparticles (MNPs) are important contrast agents used to monitor a range of neuropathological processes; microglial cells significantly contribute to MNP uptake in sites of pathology. Microglial activation occurs following most CNS pathologies but it is not known if such activation alters MNP uptake, intracellular processing and toxicity. We assessed these parameters in microglial cultures with and without experimental ‘activation’. Microglia showed rapid and extensive MNP uptake under basal conditions with no changes found following activation; significant microglial toxicity was observed at higher particle concentrations. Based on our findings, we suggest that avid MNP uptake by endogenous CNS microglia could significantly limit uptake by other cellular subtypes in mixed neural cell populations. Full article

(This article belongs to the Special Issue Magnetic Nanoparticles)

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Graphical abstract

881 KiB

Open AccessArticle

Light Dose is a Limiting Factor to Maintain Cell Viability in Fluorescence Microscopy and Single Molecule Detection

by Michael Wagner, Petra Weber, Thomas Bruns, Wolfgang S. L. Strauss, Rainer Wittig and Herbert Schneckenburger

Int. J. Mol. Sci. 2010, 11(3), 956-966; https://doi.org/10.3390/ijms11030956 - 8 Mar 2010

Cited by 61 | Viewed by 15822

Abstract

A test system for cell viability based on colony formation has been established and applied to high resolution fluorescence microscopy and single molecule detection. Living cells were irradiated either by epi-illumination or by total internal reflection (TIR) of a laser beam, and light [...] Read more.

A test system for cell viability based on colony formation has been established and applied to high resolution fluorescence microscopy and single molecule detection. Living cells were irradiated either by epi-illumination or by total internal reflection (TIR) of a laser beam, and light doses where at least 90% of irradiated cells survived were determined. These light doses were in the range of a few J/cm² up to about 200 J/cm² depending on the wavelength of illumination as well as on the presence or absence of a fluorescent dye (e.g., the membrane marker laurdan). In general, cells were less sensitive to TIR than to epi-illumination. However, comparably high light doses needed for repetitive excitation of single molecules limit the application of super-resolution microscopy to living cells. Full article

(This article belongs to the Special Issue Single Molecules)

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Graphical abstract

499 KiB

Open AccessArticle

Orientational Packing of a Confined Discotic Mesogen in the Columnar Phase

by Wenjun Zheng, Ya-Ting Hu, Cheng-Yan Chiang and Chi Wi Ong

Int. J. Mol. Sci. 2010, 11(3), 943-955; https://doi.org/10.3390/ijms11030943 - 8 Mar 2010

Cited by 15 | Viewed by 11747

Abstract

The stacking of discotic molecules (hexakis(alkoxy)diquinoxalino[2,3-a:2’,3’-c]phenazines) in the columnar phase sandwiched between two flat glass substrates has been studied. The surface free energy of the substrates, measured by means of sessile drop technique, is found to have significant influence on the way that [...] Read more.

The stacking of discotic molecules (hexakis(alkoxy)diquinoxalino[2,3-a:2’,3’-c]phenazines) in the columnar phase sandwiched between two flat glass substrates has been studied. The surface free energy of the substrates, measured by means of sessile drop technique, is found to have significant influence on the way that the discotic molecules anchor on the surface, and a steady thermal state of the system is crucial for a homogenous orientation of the discotic columns. On a surface of high free energy, the discotic molecules anchor with their disc-face toward the surface. A decrease in the surface free energy of the substrate causes the discotic columns to tilt away from the normal of the substrate. Full article

(This article belongs to the Special Issue Liquid Crystals)

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320 KiB

Open AccessArticle

Activated Carbon Modified with Copper for Adsorption of Propanethiol

by Juan Carlos Moreno-Piraján, Joaquín Tirano, Brisa Salamanca and Liliana Giraldo

Int. J. Mol. Sci. 2010, 11(3), 927-942; https://doi.org/10.3390/ijms11030927 - 4 Mar 2010

Cited by 36 | Viewed by 12923

Abstract

Activated carbons were characterized texturally and chemically before and after treatment, using surface area determination in the BET model, Boehm titration, TPR, DRX and immersion calorimetry. The adsorption capacity and the kinetics of sulphur compound removal were determined by gas chromatography. It was [...] Read more.

Activated carbons were characterized texturally and chemically before and after treatment, using surface area determination in the BET model, Boehm titration, TPR, DRX and immersion calorimetry. The adsorption capacity and the kinetics of sulphur compound removal were determined by gas chromatography. It was established that the propanethiol retention capacity is dependent on the number of oxygenated groups generated on the activated carbon surface and that activated carbon modified with CuO at 0.25 M shows the highest retention of propanethiol. Additionally is proposed a mechanism of decomposition of propenothiol with carbon-copper system. Full article

(This article belongs to the Section Physical Chemistry, Theoretical and Computational Chemistry)

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Open AccessArticle

Oxidation of Isoeugenol by Salen Complexes with Bulky Substituents

by Anika Salanti, Marco Orlandi, Eeva-Liisa Tolppa and Luca Zoia

Int. J. Mol. Sci. 2010, 11(3), 912-926; https://doi.org/10.3390/ijms11030912 - 4 Mar 2010

Cited by 28 | Viewed by 15796

Abstract

The catalytic properties of bulky water-soluble salen complexes in the oxidation of isoeugenol(2-methoxy-4-(1-propenyl) phenol) have been investigated in aqueous ethanol solutions in order to obtain a mixture of polymeric compounds through dehydrogenative polymerization. The average molecular weight of dehydrogenated polymers (DHPs) was monitored [...] Read more.

The catalytic properties of bulky water-soluble salen complexes in the oxidation of isoeugenol(2-methoxy-4-(1-propenyl) phenol) have been investigated in aqueous ethanol solutions in order to obtain a mixture of polymeric compounds through dehydrogenative polymerization. The average molecular weight of dehydrogenated polymers (DHPs) was monitored by GPC and correlated to reaction conditions such as time, concentration of substrate, concentration of catalyst, type of oxidation agent, etc. The DHP synthesized by adopting the best reaction conditions was characterized by different analytical techniques (GPC, ¹³C-NMR, ³¹P-NMR and LC-MS) to elucidate its structure. The lignin-like polymer resulting from isoeugenol radical coupling possesses valuable biological activity and finds applications in a variety of fields, such as packaging industry and cultural heritage conservation. Full article

(This article belongs to the Special Issue Phenolics and Polyphenolics)

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1853 KiB

Open AccessArticle

Degradation of Microcystin-LR and RR by a Stenotrophomonas sp. Strain EMS Isolated from Lake Taihu, China

by Jian Chen, Liang Bin Hu, Wei Zhou, Shao Hua Yan, Jing Dong Yang, Yan Feng Xue and Zhi Qi Shi

Int. J. Mol. Sci. 2010, 11(3), 896-911; https://doi.org/10.3390/ijms11030896 - 2 Mar 2010

Cited by 98 | Viewed by 15137

Abstract

A bacterial strain EMS with the capability of degrading microcystins (MCs) was isolated from Lake Taihu, China. The bacterium was tentatively identified as a Stenotrophomonas sp. The bacterium could completely consume MC-LR and MC-RR within 24 hours at a concentration of 0.7 µg/mL [...] Read more.

A bacterial strain EMS with the capability of degrading microcystins (MCs) was isolated from Lake Taihu, China. The bacterium was tentatively identified as a Stenotrophomonas sp. The bacterium could completely consume MC-LR and MC-RR within 24 hours at a concentration of 0.7 µg/mL and 1.7 µg/mL, respectively. The degradation of MC-LR and MC-RR by EMS occurred preferentially in an alkaline environment. In addition, mlrA gene involved in the degradation of MC-LR and MC-RR was detected in EMS. Due to the limited literature this gene has rare homologues. Sequencing analysis of the translated protein from mlrA suggested that MlrA might be a transmembrane protein, which suggests a possible new protease family having unique function. Full article

(This article belongs to the Section Biochemistry)

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456 KiB

Open AccessArticle

QSAR Studies on Andrographolide Derivatives as α-Glucosidase Inhibitors

by Jun Xu, Sichao Huang, Haibin Luo, Guoji Li, Jiaolin Bao, Shaohui Cai and Yuqiang Wang

Int. J. Mol. Sci. 2010, 11(3), 880-895; https://doi.org/10.3390/ijms11030880 - 2 Mar 2010

Cited by 21 | Viewed by 12870

Abstract

Andrographolide derivatives were shown to inhibit α-glucosidase. To investigate the relationship between activities and structures of andrographolide derivatives, a training set was chosen from 25 andrographolide derivatives by the principal component analysis (PCA) method, and a quantitative structure-activity relationship (QSAR) was established by [...] Read more.

Andrographolide derivatives were shown to inhibit α-glucosidase. To investigate the relationship between activities and structures of andrographolide derivatives, a training set was chosen from 25 andrographolide derivatives by the principal component analysis (PCA) method, and a quantitative structure-activity relationship (QSAR) was established by 2D and 3D QSAR methods. The cross-validation r² (0.731) and standard error (0.225) illustrated that the 2D-QSAR model was able to identify the important molecular fragments and the cross-validation r² (0.794) and standard error (0.127) demonstrated that the 3D-QSAR model was capable of exploring the spatial distribution of important fragments. The obtained results suggested that proposed combination of 2D and 3D QSAR models could be useful in predicting the α-glucosidase inhibiting activity of andrographolide derivatives. Full article

(This article belongs to the Special Issue Recent Advances in QSAR/QSPR Theory)

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218 KiB

Open AccessReview

Miniaturization in Biocatalysis

by Pedro Fernandes

Int. J. Mol. Sci. 2010, 11(3), 858-879; https://doi.org/10.3390/ijms11030858 - 2 Mar 2010

Cited by 73 | Viewed by 14900

Abstract

The use of biocatalysts for the production of both consumer goods and building blocks for chemical synthesis is consistently gaining relevance. A significant contribution for recent advances towards further implementation of enzymes and whole cells is related to the developments in miniature reactor [...] Read more.

The use of biocatalysts for the production of both consumer goods and building blocks for chemical synthesis is consistently gaining relevance. A significant contribution for recent advances towards further implementation of enzymes and whole cells is related to the developments in miniature reactor technology and insights into flow behavior. Due to the high level of parallelization and reduced requirements of chemicals, intensive screening of biocatalysts and process variables has become more feasible and reproducibility of the bioconversion processes has been substantially improved. The present work aims to provide an overview of the applications of miniaturized reactors in bioconversion processes, considering multi-well plates and microfluidic devices, update information on the engineering characterization of the hardware used, and present perspective developments in this area of research. Full article

(This article belongs to the Special Issue Biocatalysis)

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710 KiB

Open AccessReview

Managing Phenol Contents in Crop Plants by Phytochemical Farming and Breeding—Visions and Constraints

by Dieter Treutter

Int. J. Mol. Sci. 2010, 11(3), 807-857; https://doi.org/10.3390/ijms11030807 - 2 Mar 2010

Cited by 178 | Viewed by 25328

Abstract

Two main fields of interest form the background of actual demand for optimized levels of phenolic compounds in crop plants. These are human health and plant resistance to pathogens and to biotic and abiotic stress factors. A survey of agricultural technologies influencing the [...] Read more.

Two main fields of interest form the background of actual demand for optimized levels of phenolic compounds in crop plants. These are human health and plant resistance to pathogens and to biotic and abiotic stress factors. A survey of agricultural technologies influencing the biosynthesis and accumulation of phenolic compounds in crop plants is presented, including observations on the effects of light, temperature, mineral nutrition, water management, grafting, elevated atmospheric CO₂, growth and differentiation of the plant and application of elicitors, stimulating agents and plant activators. The underlying mechanisms are discussed with respect to carbohydrate availability, trade-offs to competing demands as well as to regulatory elements. Outlines are given for genetic engineering and plant breeding. Constraints and possible physiological feedbacks are considered for successful and sustainable application of agricultural techniques with respect to management of plant phenol profiles and concentrations. Full article

(This article belongs to the Special Issue Phenolics and Polyphenolics)

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407 KiB

Open AccessReview

Interleukin 12 a Key Immunoregulatory Cytokine in Infection Applications

by Therwa Hamza, John B. Barnett and Bingyun Li

Int. J. Mol. Sci. 2010, 11(3), 789-806; https://doi.org/10.3390/ijms11030789 - 26 Feb 2010

Cited by 278 | Viewed by 32543

Abstract

Interleukin 12 (termed IL-12p70 and commonly designated IL-12) is an important immunoregulatory cytokine that is produced mainly by antigen-presenting cells. The expression of IL-12 during infection regulates innate responses and determines the type of adaptive immune responses. IL-12 induces interferon-γ (IFN-γ) production and [...] Read more.

Interleukin 12 (termed IL-12p70 and commonly designated IL-12) is an important immunoregulatory cytokine that is produced mainly by antigen-presenting cells. The expression of IL-12 during infection regulates innate responses and determines the type of adaptive immune responses. IL-12 induces interferon-γ (IFN-γ) production and triggers CD4+ T cells to differentiate into type 1 T helper (Th1) cells. Studies have suggested that IL-12 could play a vital role in treating many diseases, such as viral and bacterial infections and cancers. The unique heterodimeric structure, which IL-12 shares with its family members including IL-23, IL-27, and IL-35, has recently brought more attention to understanding the mechanisms that regulate the functions of IL-12. This article describes the structure and biological activities of IL-12 in both the innate and adaptive arms of the immune system, and discusses the applications of IL-12 in treating and preventing infections. Full article

(This article belongs to the Special Issue Molecular Biomimetics and Materials Design)

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Int. J. Mol. Sci., Volume 11, Issue 3 (March 2010) – 23 articles , Pages 789-1189

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