International Journal of Molecular Sciences

1058 KiB

Open AccessArticle

Synthesis Mechanism of Low-Voltage Praseodymium Oxide Doped Zinc Oxide Varistor Ceramics Prepared Through Modified Citrate Gel Coating

by Wan Rafizah Wan Abdullah, Azmi Zakaria and Mohd Sabri Mohd Ghazali

Int. J. Mol. Sci. 2012, 13(4), 5278-5289; https://doi.org/10.3390/ijms13045278 - 24 Apr 2012

Cited by 35 | Viewed by 7431

Abstract

High demands on low-voltage electronics have increased the need for zinc oxide (ZnO) varistors with fast response, highly non-linear current-voltage characteristics and energy absorption capabilities at low breakdown voltage. However, trade-off between breakdown voltage and grain size poses a critical bottle-neck in the [...] Read more.

High demands on low-voltage electronics have increased the need for zinc oxide (ZnO) varistors with fast response, highly non-linear current-voltage characteristics and energy absorption capabilities at low breakdown voltage. However, trade-off between breakdown voltage and grain size poses a critical bottle-neck in the production of low-voltage varistors. The present study highlights the synthesis mechanism for obtaining praseodymium oxide (Pr₆O₁₁) based ZnO varistor ceramics having breakdown voltages of 2.8 to 13.3 V/mm through employment of direct modified citrate gel coating technique. Precursor powder and its ceramics were examined by means of TG/DTG, FTIR, XRD and FESEM analyses. The electrical properties as a function of Pr₆O₁₁ addition were analyzed on the basis of I-V characteristic measurement. The breakdown voltage could be adjusted from 0.01 to 0.06 V per grain boundary by controlling the amount of Pr₆O₁₁ from 0.2 to 0.8 mol%, without alteration of the grain size. The non-linearity coefficient, α, varied from 3.0 to 3.5 and the barrier height ranged from 0.56 to 0.64 eV. Breakdown voltage and α lowering with increasing Pr₆O₁₁ content were associated to reduction in the barrier height caused by variation in O vacancies at grain boundary. Full article

(This article belongs to the Section Materials Science)

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390 KiB

Open AccessReview

Phage Displayed Peptides/Antibodies Recognizing Growth Factors and Their Tyrosine Kinase Receptors as Tools for Anti-Cancer Therapeutics

by Roberto Ronca, Patrizia Benzoni, Angela De Luca, Elisabetta Crescini and Patrizia Dell’Era

Int. J. Mol. Sci. 2012, 13(4), 5254-5277; https://doi.org/10.3390/ijms13045254 - 24 Apr 2012

Cited by 6 | Viewed by 8376

Abstract

The basic idea of displaying peptides on a phage, introduced by George P. Smith in 1985, was greatly developed and improved by McCafferty and colleagues at the MRC Laboratory of Molecular Biology and, later, by Barbas and colleagues at the Scripps Research Institute. [...] Read more.

The basic idea of displaying peptides on a phage, introduced by George P. Smith in 1985, was greatly developed and improved by McCafferty and colleagues at the MRC Laboratory of Molecular Biology and, later, by Barbas and colleagues at the Scripps Research Institute. Their approach was dedicated to building a system for the production of antibodies, similar to a naïve B cell repertoire, in order to by-pass the standard hybridoma technology that requires animal immunization. Both groups merged the phage display technology with an antibody library to obtain a huge number of phage variants, each of them carrying a specific antibody ready to bind its target molecule, allowing, later on, rare phage (one in a million) to be isolated by affinity chromatography. Here, we will briefly review the basis of the technology and the therapeutic application of phage-derived bioactive molecules when addressed against key players in tumor development and progression: growth factors and their tyrosine kinase receptors. Full article

(This article belongs to the Special Issue Phage Display)

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638 KiB

Open AccessArticle

Sol-Gel-Derived Hydroxyapatite-Carbon Nanotube/Titania Coatings on Titanium Substrates

by Xiaoli Ji, Weiwei Lou, Qi Wang, Jianfeng Ma, Haihong Xu, Qing Bai, Chuantong Liu and Jinsong Liu

Int. J. Mol. Sci. 2012, 13(4), 5242-5253; https://doi.org/10.3390/ijms13045242 - 24 Apr 2012

Cited by 37 | Viewed by 8910

Abstract

In this paper, hydroxyapatite-carbon nanotube/titania (HA-CNT/TiO₂) double layer coatings were successfully developed on titanium (Ti) substrates intended for biomedical applications. A TiO₂ coating was firstly developed by anodization to improve bonding between HA and Ti, and then the layer of [...] Read more.

In this paper, hydroxyapatite-carbon nanotube/titania (HA-CNT/TiO₂) double layer coatings were successfully developed on titanium (Ti) substrates intended for biomedical applications. A TiO₂ coating was firstly developed by anodization to improve bonding between HA and Ti, and then the layer of HA and CNTs was coated on the surface by the sol-gel process to improve the biocompatibility and mechanical properties of Ti. The surfaces of double layer coatings were uniform and crack-free with a thickness of about 7 μm. The bonding strength of the HA-CNT/TiO₂ coating was higher than that of the pure HA and HA-CNT coatings. Additionally, in vitro cell experiments showed that CNTs promoted the adhesion of preosteoblasts on the HA-CNT/TiO₂ double layer coatings. These unique surfaces combined with the osteoconductive properties of HA exhibited the excellent mechanical properties of CNTs. Therefore, the developed HA-CNT/TiO₂ coatings on Ti substrates might be a promising material for bone replacement. Full article

(This article belongs to the Section Materials Science)

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417 KiB

Open AccessArticle

Enhanced Production of a Novel Cyclic Hexapeptide Antibiotic (NW-G01) by Streptomyces alboflavus 313 Using Response Surface Methodology

by Zhengyan Guo, Ling Shen, Zhiqin Ji and Wenjun Wu

Int. J. Mol. Sci. 2012, 13(4), 5230-5241; https://doi.org/10.3390/ijms13045230 - 24 Apr 2012

Cited by 19 | Viewed by 7413

Abstract

NW-G01, produced by Streptomyces alboflavus 313, is a novel cyclic hexapeptide antibiotic with many potential applications, including antimicrobial activity and antitumor agents. This study developed a system for optimizing medium components in order to enhance NW-G01 production. In this study, Plackett-Burman design (PBD) [...] Read more.

NW-G01, produced by Streptomyces alboflavus 313, is a novel cyclic hexapeptide antibiotic with many potential applications, including antimicrobial activity and antitumor agents. This study developed a system for optimizing medium components in order to enhance NW-G01 production. In this study, Plackett-Burman design (PBD) was used to find the key ingredients of medium components, and then response surface methodology (RSM) was implemented to determine their optimal concentrations. The results of PBD revealed that the crucial ingredients related to the production of NW-G01 were (NH₄)₂SO₄, peptone and CaCO₃. A prediction model has been built in the experiments of central composite design and response surface methodology, and its validation has been further verified. The optimal medium composition was determined (g/L): corn starch 15, glucose 15, peptone 3.80, (NH₄)₂SO₄ 0.06, NaCl 1.5, CaCO₃ 1.30, MgSO₄·7H₂O 0.015, K₂HPO₄·3H₂O 0.015, MnCl₂·4H₂O 0.015, FeSO₄·7H₂O 0.015, and ZnSO₄·7H₂O 0.015. Compared with NW-G01 production (5.707 mg/L) in non-optimized fermentation medium, the production of NW-G01 (15.564 mg/L) in optimized fermentation medium had a 2.73-fold increase. Full article

(This article belongs to the Section Biochemistry)

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519 KiB

Open AccessArticle

Poisson Parameters of Antimicrobial Activity: A Quantitative Structure-Activity Approach

by Radu E. Sestraş, Lorentz Jäntschi and Sorana D. Bolboacă

Int. J. Mol. Sci. 2012, 13(4), 5207-5229; https://doi.org/10.3390/ijms13045207 - 24 Apr 2012

Cited by 7 | Viewed by 7868

Abstract

A contingency of observed antimicrobial activities measured for several compounds vs. a series of bacteria was analyzed. A factor analysis revealed the existence of a certain probability distribution function of the antimicrobial activity. A quantitative structure-activity relationship analysis for the overall antimicrobial [...] Read more.

A contingency of observed antimicrobial activities measured for several compounds vs. a series of bacteria was analyzed. A factor analysis revealed the existence of a certain probability distribution function of the antimicrobial activity. A quantitative structure-activity relationship analysis for the overall antimicrobial ability was conducted using the population statistics associated with identified probability distribution function. The antimicrobial activity proved to follow the Poisson distribution if just one factor varies (such as chemical compound or bacteria). The Poisson parameter estimating antimicrobial effect, giving both mean and variance of the antimicrobial activity, was used to develop structure-activity models describing the effect of compounds on bacteria and fungi species. Two approaches were employed to obtain the models, and for every approach, a model was selected, further investigated and found to be statistically significant. The best predictive model for antimicrobial effect on bacteria and fungi species was identified using graphical representation of observed vs. calculated values as well as several predictive power parameters. Full article

(This article belongs to the Special Issue Advances in Biomolecular Simulation)

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Graphical abstract

386 KiB

Open AccessReview

Localization of Axonal Motor Molecules Machinery in Neurodegenerative Disorders

by Fulvio Florenzano

Int. J. Mol. Sci. 2012, 13(4), 5195-5206; https://doi.org/10.3390/ijms13045195 - 24 Apr 2012

Cited by 6 | Viewed by 6011

Abstract

Axonal transport and neuronal survival depend critically on active transport and axon integrity both for supplying materials and communication to different domains of the cell body. All these actions are executed through cytoskeleton, transport and regulatory elements that appear to be disrupted in [...] Read more.

Axonal transport and neuronal survival depend critically on active transport and axon integrity both for supplying materials and communication to different domains of the cell body. All these actions are executed through cytoskeleton, transport and regulatory elements that appear to be disrupted in neurodegenerative diseases. Motor-driven transport both supplies and clears distal cellular portions with proteins and organelles. This transport is especially relevant in projection and motor neurons, which have long axons to reach the farthest nerve endings. Thus, any disturbance of axonal transport may have severe consequences for neuronal function and survival. A growing body of literature indicates the presence of alterations to the motor molecules machinery, not only in expression levels and phosphorylation, but also in their subcellular distribution within populations of neurons, which are selectively affected in the course of neurodegenerative diseases. The implications of this altered subcellular localization and how this affects axon survival and neuronal death still remain poorly understood, although several hypotheses have been suggested. Furthermore, cytoskeleton and transport element localization can be selectively disrupted in some disorders suggesting that specific loss of the axonal functionality could be a primary hallmark of the disorder. This can lead to axon degeneration and neuronal death either directly, through the functional absence of essential axonal proteins, or indirectly, through failures in communication among different cellular domains. This review compares the localization of cytoskeleton and transport elements in some neurodegenerative disorders to ask what aspects may be essential for axon survival and neuronal death. Full article

(This article belongs to the Section Biochemistry)

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215 KiB

Open AccessReview

Filamentous Bacteriophage Fd as an Antigen Delivery System in Vaccination

by Antonella Prisco and Piergiuseppe De Berardinis

Int. J. Mol. Sci. 2012, 13(4), 5179-5194; https://doi.org/10.3390/ijms13045179 - 24 Apr 2012

Cited by 50 | Viewed by 11400

Abstract

Peptides displayed on the surface of filamentous bacteriophage fd are able to induce humoral as well as cell-mediated immune responses, which makes phage particles an attractive antigen delivery system to design new vaccines. The immune response induced by phage-displayed peptides can be enhanced [...] Read more.

Peptides displayed on the surface of filamentous bacteriophage fd are able to induce humoral as well as cell-mediated immune responses, which makes phage particles an attractive antigen delivery system to design new vaccines. The immune response induced by phage-displayed peptides can be enhanced by targeting phage particles to the professional antigen presenting cells, utilizing a single-chain antibody fragment that binds dendritic cell receptor DEC-205. Here, we review recent advances in the use of filamentous phage fd as a platform for peptide vaccines, with a special focus on the use of phage fd as an antigen delivery platform for peptide vaccines in Alzheimer’s Disease and cancer. Full article

(This article belongs to the Special Issue Phage Display)

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673 KiB

Open AccessArticle

Application of Ionic Liquids in the Microwave-Assisted Extraction of Proanthocyanidins from Larix gmelini Bark

by Lei Yang, Xiaowei Sun, Fengjian Yang, Chunjian Zhao, Lin Zhang and Yuangang Zu

Int. J. Mol. Sci. 2012, 13(4), 5163-5178; https://doi.org/10.3390/ijms13045163 - 24 Apr 2012

Cited by 58 | Viewed by 8122

Abstract

Ionic liquid based, microwave-assisted extraction (ILMAE) was successfully applied to the extraction of proanthocyanidins from Larix gmelini bark. In this work, in order to evaluate the performance of ionic liquids in the microwave-assisted extraction process, a series of 1-alkyl-3-methylimidazolium ionic liquids with different [...] Read more.

Ionic liquid based, microwave-assisted extraction (ILMAE) was successfully applied to the extraction of proanthocyanidins from Larix gmelini bark. In this work, in order to evaluate the performance of ionic liquids in the microwave-assisted extraction process, a series of 1-alkyl-3-methylimidazolium ionic liquids with different cations and anions were evaluated for extraction yield, and 1-butyl-3-methylimidazolium bromide was selected as the optimal solvent. In addition, the ILMAE procedure for the proanthocyanidins was optimized and compared with other conventional extraction techniques. Under the optimized conditions, satisfactory extraction yield of the proanthocyanidins was obtained. Relative to other methods, the proposed approach provided higher extraction yield and lower energy consumption. The Larix gmelini bark samples before and after extraction were analyzed by Thermal gravimetric analysis, Fourier-transform infrared spectroscopy and characterized by scanning electron microscopy. The results showed that the ILMAE method is a simple and efficient technique for sample preparation. Full article

(This article belongs to the Section Green Chemistry)

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929 KiB

Open AccessArticle

Identification of Important Chemical Features of 11β-Hydroxysteroid Dehydrogenase Type1 Inhibitors: Application of Ligand Based Virtual Screening and Density Functional Theory

by Sugunadevi Sakkiah, Chandrasekaran Meganathan, Young-Sik Sohn, Sundaraganesan Namadevan and Keun Woo Lee

Int. J. Mol. Sci. 2012, 13(4), 5138-5162; https://doi.org/10.3390/ijms13045138 - 23 Apr 2012

Cited by 32 | Viewed by 7282

Abstract

11ß-Hydroxysteroid dehydrogenase type1 (11ßHSD1) regulates the conversion from inactive cortisone to active cortisol. Increased cortisol results in diabetes, hence quelling the activity of 11ßHSD1 has been thought of as an effective approach for the treatment of diabetes. Quantitative hypotheses were developed and validated [...] Read more.

11ß-Hydroxysteroid dehydrogenase type1 (11ßHSD1) regulates the conversion from inactive cortisone to active cortisol. Increased cortisol results in diabetes, hence quelling the activity of 11ßHSD1 has been thought of as an effective approach for the treatment of diabetes. Quantitative hypotheses were developed and validated to identify the critical chemical features with reliable geometric constraints that contribute to the inhibition of 11ßHSD1 function. The best hypothesis, Hypo1, which contains one-HBA; one-Hy-Ali, and two-RA features, was validated using Fischer’s randomization method, a test and a decoy set. The well validated, Hypo1, was used as 3D query to perform a virtual screening of three different chemical databases. Compounds selected by Hypo1 in the virtual screening were filtered by applying Lipinski’s rule of five, ADMET, and molecular docking. Finally, five hit compounds were selected as virtual novel hit molecules for 11ßHSD1 based on their electronic properties calculated by Density functional theory. Full article

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Graphical abstract

691 KiB

Open AccessArticle

A DNA Network as an Information Processing System

by Cristina Costa Santini, Jonathan Bath, Andrew J. Turberfield and Andy M. Tyrrell

Int. J. Mol. Sci. 2012, 13(4), 5125-5137; https://doi.org/10.3390/ijms13045125 - 23 Apr 2012

Cited by 11 | Viewed by 7905

Abstract

Biomolecular systems that can process information are sought for computational applications, because of their potential for parallelism and miniaturization and because their biocompatibility also makes them suitable for future biomedical applications. DNA has been used to design machines, motors, finite automata, logic gates, [...] Read more.

Biomolecular systems that can process information are sought for computational applications, because of their potential for parallelism and miniaturization and because their biocompatibility also makes them suitable for future biomedical applications. DNA has been used to design machines, motors, finite automata, logic gates, reaction networks and logic programs, amongst many other structures and dynamic behaviours. Here we design and program a synthetic DNA network to implement computational paradigms abstracted from cellular regulatory networks. These show information processing properties that are desirable in artificial, engineered molecular systems, including robustness of the output in relation to different sources of variation. We show the results of numerical simulations of the dynamic behaviour of the network and preliminary experimental analysis of its main components. Full article

(This article belongs to the Section Biochemistry)

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Graphical abstract

858 KiB

Open AccessArticle

Genome-Wide Identification and in Silico Analysis of Poplar Peptide Deformylases

by Chang-Cai Liu, Bao-Guang Liu, Zhi-Wei Yang, Chun-Ming Li, Bai-Chen Wang and Chuan-Ping Yang

Int. J. Mol. Sci. 2012, 13(4), 5112-5124; https://doi.org/10.3390/ijms13045112 - 23 Apr 2012

Cited by 4 | Viewed by 6706

Abstract

Peptide deformylases (PDF) behave as monomeric metal cation hydrolases for the removal of the N-formyl group (Fo). This is an essential step in the N-terminal Met excision (NME) that occurs in these proteins from eukaryotic mitochondria or chloroplasts. Although PDFs have [...] Read more.

Peptide deformylases (PDF) behave as monomeric metal cation hydrolases for the removal of the N-formyl group (Fo). This is an essential step in the N-terminal Met excision (NME) that occurs in these proteins from eukaryotic mitochondria or chloroplasts. Although PDFs have been identified and their structure and function have been characterized in several herbaceous species, it remains as yet unexplored in poplar. Here, we report on the first identification of two genes (PtrPDF1A and PtrPDF1B) respectively encoding two putative PDF polypeptides in Populus trichocarpa by genome-wide investigation. One of them (XP_002300047.1) encoded by PtrPDF1B (XM_002300011.1) was truncated, and then revised into a complete sequence based on its ESTs support with high confidence. We document that the two PDF1s of Populus are evolutionarily divergent, likely as a result of independent duplicated events. Furthermore, in silico simulations demonstrated that PtrPDF1A and PtrPDF1B should act as similar PDF catalytic activities to their corresponding PDF orthologs in Arabidopsis. This result would be value of for further assessment of their biological activities in poplar, and further experiments are now required to confirm them. Full article

(This article belongs to the Section Biochemistry)

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Open AccessArticle

The Establishment of a Primary Culture System of Proximal Tubule Segments Using Specific Markers from Normal Mouse Kidneys

by Masumi Kamiyama, Michelle K. Garner, Kristina M. Farragut and Hiroyuki Kobori

Int. J. Mol. Sci. 2012, 13(4), 5098-5111; https://doi.org/10.3390/ijms13045098 - 23 Apr 2012

Cited by 35 | Viewed by 9623

Abstract

The proximal tubule contains the highest expression of angiotensinogen mRNA and protein within the kidney and plays a vital role in the renal renin-angiotensin system. To study the regulation of angiotensinogen expression in the kidney in more detail, the proximal tubule needs to [...] Read more.

The proximal tubule contains the highest expression of angiotensinogen mRNA and protein within the kidney and plays a vital role in the renal renin-angiotensin system. To study the regulation of angiotensinogen expression in the kidney in more detail, the proximal tubule needs to be accurately isolated from the rest of the nephron and separated into its three segments. The purpose of this study was to design a novel protocol using specific markers for the separation of proximal tubule cells into the three proximal tubule segments and to determine angiotensinogen expression in each segment. Kidneys were removed from C57BL/6J mice. The proximal tubules were aspirated from region of a Percoll gradient solution of the appropriate density. The proximal tubule was then separated into its three segments using segment-specific membrane proteins, after which each segment was characterized by a different specific marker (sodium-glucose transporter 2 for Segment 1; carbonic anhydrase IV for Segment 2; ecto-adenosine triphosphatase for Segment 3). The isolation of proximal tubules into three segments was successful, and angiotensinogen mRNA in Segment 2 and 3 and angiotensinogen protein in all three segments were confirmed. This protocol will be helpful for future studies of the detailed mechanisms of the intrarenal renin-angiotensin system. Full article

(This article belongs to the Section Biochemistry)

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1732 KiB

Open AccessArticle

Rhinacanthus nasutus Extracts Prevent Glutamate and Amyloid-β Neurotoxicity in HT-22 Mouse Hippocampal Cells: Possible Active Compounds Include Lupeol, Stigmasterol and β-Sitosterol

by James M. Brimson, Sirikalaya J. Brimson, Christopher A. Brimson, Varaporn Rakkhitawatthana and Tewin Tencomnao

Int. J. Mol. Sci. 2012, 13(4), 5074-5097; https://doi.org/10.3390/ijms13045074 - 23 Apr 2012

Cited by 69 | Viewed by 14918

Abstract

The Herb Rhinacanthus nasutus (L.) Kurz, which is native to Thailand and Southeast Asia, has become known for its antioxidant properties. Neuronal loss in a number of diseases including Alzheimer’s disease is thought to result, in part, from oxidative stress. Glutamate causes cell [...] Read more.

The Herb Rhinacanthus nasutus (L.) Kurz, which is native to Thailand and Southeast Asia, has become known for its antioxidant properties. Neuronal loss in a number of diseases including Alzheimer’s disease is thought to result, in part, from oxidative stress. Glutamate causes cell death in the mouse hippocampal cell line, HT-22, by unbalancing redox homeostasis, brought about by a reduction in glutathione levels, and amyloid-β has been shown to induce reactive oxygen species (ROS) production. Here in, we show that ethanol extracts of R. nasutus leaf and root are capable of dose dependently attenuating the neuron cell death caused by both glutamate and amyloid-β treatment. We used free radical scavenging assays to measure the extracts antioxidant activities and as well as quantifying phenolic, flavonoid and sterol content. Molecules found in R. nasutus, lupeol, stigmasterol and β-sitosterol are protective against glutamate toxicity. Full article

(This article belongs to the Section Biochemistry)

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Open AccessArticle

Preparation and Characterization of Micronized Artemisinin via a Rapid Expansion of Supercritical Solutions (RESS) Method

by Huimin Yu, Xiuhua Zhao, Yuangang Zu, Xinjuan Zhang, Baishi Zu and Xiaonan Zhang

Int. J. Mol. Sci. 2012, 13(4), 5060-5073; https://doi.org/10.3390/ijms13045060 - 23 Apr 2012

Cited by 32 | Viewed by 8298

Abstract

The particle sizes of pharmaceutical substances are important for their bioavailability. Bioavailability can be improved by reducing the particle size of the drug. In this study, artemisinin was micronized by the rapid expansion of supercritical solutions (RESS). The particle size of the unprocessed [...] Read more.

The particle sizes of pharmaceutical substances are important for their bioavailability. Bioavailability can be improved by reducing the particle size of the drug. In this study, artemisinin was micronized by the rapid expansion of supercritical solutions (RESS). The particle size of the unprocessed white needle-like artemisinin particles was 30 to 1200 µm. The optimum micronization conditions are determined as follows: extraction temperature of 62 °C, extraction pressure of 25 MPa, precipitation temperature 45 °C and nozzle diameter of 1000 μm. Under the optimum conditions, micronized artemisinin with a (mean particle size) MPS of 550 nm is obtained. By analysis of variance (ANOVA), extraction temperature and pressure have significant effects on the MPS of the micronized artemisinin. The particle size of micronized artemisinin decreased with increasing extraction temperature and pressure. Moreover, the SEM, LC-MS, FTIR, DSC and XRD allowed the comparison between the crystalline initial state and the micronization particles obtained after the RESS process. The results showed that RESS process has not induced degradation of artemisinin and that processed artemisinin particles have lower crystallinity and melting point. The bulk density of artemisinin was determined before and after RESS process and the obtained results showed that it passes from an initial density of 0.554 to 0.128 g·cm⁻³ after the processing. The decrease in bulk density of the micronized powder can increase the liquidity of drug particles when they are applied for medicinal preparations. These results suggest micronized powder of artemisinin can be of great potential in drug delivery systems. Full article

(This article belongs to the Section Materials Science)

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223 KiB

Open AccessArticle

Nonselective Blocking of the Sympathetic Nervous System Decreases Detrusor Overactivity in Spontaneously Hypertensive Rats

by Khae-Hawn Kim, Long-Hu Jin, Gwoan-Youb Choo, Hun-Jae Lee, Bo-Hwa Choi, Jiyeon Kwak, Sang-Min Yoon, Chang-Shin Park and Tack Lee

Int. J. Mol. Sci. 2012, 13(4), 5048-5059; https://doi.org/10.3390/ijms13045048 - 23 Apr 2012

Cited by 4 | Viewed by 6850

Abstract

The involuntary dual control systems of the autonomic nervous system (ANS) in the bladder of awake spontaneously hypertensive rats (SHRs) were investigated through simultaneous registrations of intravesical and intraabdominal pressures to observe detrusor overactivity (DO) objectively as a core symptom of an overactive [...] Read more.

The involuntary dual control systems of the autonomic nervous system (ANS) in the bladder of awake spontaneously hypertensive rats (SHRs) were investigated through simultaneous registrations of intravesical and intraabdominal pressures to observe detrusor overactivity (DO) objectively as a core symptom of an overactive bladder. SHRs (n = 6) showed the features of overactive bladder syndrome during urodynamic study, especially DO during the filling phase. After injection of the nonselective sympathetic blocking agent labetalol, DO disappeared in 3 of 6 SHRs (50%). DO frequency decreased from 0.98 ± 0.22 min⁻¹ to 0.28 ± 0.19 min⁻¹ (p < 0.01), and DO pressure decreased from 3.82 ± 0.57 cm H₂O to 1.90 ± 0.86 cm H₂O (p < 0.05). This suggests that the DO originating from the overactive parasympathetic nervous system is attenuated by the nonselective blocking of the sympathetic nervous system. The detailed mechanism behind this result is still not known, but parasympathetic overactivity seems to require overactive sympathetic nervous system activity in a kind of balance between these two systems. These findings are consistent with recent clinical findings suggesting that patients with idiopathic overactive bladder may have ANS dysfunction, particularly a sympathetic dysfunction. The search for newer and better drugs than the current anticholinergic drugs as the mainstay for overactive bladder will be fueled by our research on these sympathetic mechanisms. Further studies of this principle are required. Full article

(This article belongs to the Section Biochemistry)

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Open AccessArticle

A Novel and Expedient Approach to New Thiazoles, Thiazolo[3,2-a]pyridines, Dihydrothiophenes, and Hydrazones Incorporating Thieno[2,3-b]thiophene Moiety

by Yahia Nasser Mabkhot, Assem Barakat, Abdullah Mohammad Al-Majid, Abdullah Saleh Alamary and Taleb T. Al-Nahary

Int. J. Mol. Sci. 2012, 13(4), 5035-5047; https://doi.org/10.3390/ijms13045035 - 23 Apr 2012

Cited by 14 | Viewed by 6215

Abstract

This paper reports details about the synthesis of a series of novel functionalized symmetrical bis-heterocyclic compounds containing a thieno[2,3-b]thiophene motif. Bis-thiazole derivatives 2, 3a-c and thiazolo[3,2-a]pyridine derivatives 4a-c are achieved. The hitherto unknown dihydrothiophene derivatives 6a-d via bis-pyridimium [...] Read more.

This paper reports details about the synthesis of a series of novel functionalized symmetrical bis-heterocyclic compounds containing a thieno[2,3-b]thiophene motif. Bis-thiazole derivatives 2, 3a-c and thiazolo[3,2-a]pyridine derivatives 4a-c are achieved. The hitherto unknown dihydrothiophene derivatives 6a-d via bis-pyridimium salt 5 are obtained. Additionally, the novel hydrazonothieno[2,3-b]thiophene derivatives 10a-c are obtained via bis-tosylacetylthieno[2,3-b]thiophene derivative 9. All compounds are characterized by ¹H-, ¹³C-NMR, GCMS, IR, and UV-vis spectrometry. These compounds represent a new class of sulfur and nitrogen containing heterocycles that should also be of interest as new materials. Full article

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Open AccessArticle

Na⁺, K⁺-ATPase Subunit Composition in a Human Chondrocyte Cell Line; Evidence for the Presence of α1, α3, β1, β2 and β3 Isoforms

by Ali Mobasheri, Elisa Trujillo, Mari-Francis Arteaga and Pablo Martín-Vasallo

Int. J. Mol. Sci. 2012, 13(4), 5019-5034; https://doi.org/10.3390/ijms13045019 - 20 Apr 2012

Cited by 12 | Viewed by 6992

Abstract

Membrane transport systems participate in fundamental activities such as cell cycle control, proliferation, survival, volume regulation, pH maintenance and regulation of extracellular matrix synthesis. Multiple isoforms of Na⁺, K⁺-ATPase are expressed in primary chondrocytes. Some of these isoforms have [...] Read more.

Membrane transport systems participate in fundamental activities such as cell cycle control, proliferation, survival, volume regulation, pH maintenance and regulation of extracellular matrix synthesis. Multiple isoforms of Na⁺, K⁺-ATPase are expressed in primary chondrocytes. Some of these isoforms have previously been reported to be expressed exclusively in electrically excitable cells (i.e., cardiomyocytes and neurons). Studying the distribution of Na⁺, K⁺-ATPase isoforms in chondrocytes makes it possible to document the diversity of isozyme pairing and to clarify issues concerning Na⁺, K⁺-ATPase isoform abundance and the physiological relevance of their expression. In this study, we investigated the expression of Na⁺, K⁺-ATPase in a human chondrocyte cell line (C-20/A4) using a combination of immunological and biochemical techniques. A panel of well-characterized antibodies revealed abundant expression of the α1, β1 and β2 isoforms. Western blot analysis of plasma membranes confirmed the above findings. Na⁺, K⁺-ATPase consists of multiple isozyme variants that endow chondrocytes with additional homeostatic control capabilities. In terms of Na⁺, K⁺-ATPase expression, the C-20/A4 cell line is phenotypically similar to primary and in situ chondrocytes. However, unlike freshly isolated chondrocytes, C-20/A4 cells are an easily accessible and convenient in vitro model for the study of Na⁺, K⁺-ATPase expression and regulation in chondrocytes. Full article

(This article belongs to the Special Issue Membrane Transport)

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Open AccessArticle

Aristolactam-Type Alkaloids from Orophea enterocarpa and Their Cytotoxicities

by Sanchai Nayyatip, Pak Thaichana, Mongkol Buayairaksa, Wirote Tuntiwechapikul, Puttinan Meepowpan, Narong Nuntasaen and Wilart Pompimon

Int. J. Mol. Sci. 2012, 13(4), 5010-5018; https://doi.org/10.3390/ijms13045010 - 20 Apr 2012

Cited by 20 | Viewed by 6337

Abstract

A new aristolactam, named enterocarpam-III (10-amino-2,3,4,6-tetramethoxy phenanthrene-1-carboxylic acid lactam, 1) together with the known alkaloid stigmalactam (2), were isolated from Orophea enterocarpa. Their structures were elucidated on the basis of interpretation of their spectroscopic data. Compounds 1 and 2 [...] Read more.

A new aristolactam, named enterocarpam-III (10-amino-2,3,4,6-tetramethoxy phenanthrene-1-carboxylic acid lactam, 1) together with the known alkaloid stigmalactam (2), were isolated from Orophea enterocarpa. Their structures were elucidated on the basis of interpretation of their spectroscopic data. Compounds 1 and 2 exhibited significant cytotoxicities against human colon adenocarcinoma (HCT15) cell line with IC₅₀ values of 1.68 and 1.32 μM, respectively. Full article

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Open AccessArticle

Effects of Inflorescence Stem Structure and Cell Wall Components on the Mechanical Strength of Inflorescence Stem in Herbaceous Peony

by Daqiu Zhao, Chenxia Han, Jun Tao, Jing Wang, Zhaojun Hao, Qingping Geng and Bei Du

Int. J. Mol. Sci. 2012, 13(4), 4993-5009; https://doi.org/10.3390/ijms13044993 - 19 Apr 2012

Cited by 28 | Viewed by 8345

Abstract

Herbaceous peony (Paeonia lactiflora Pall.) is a traditional famous flower, but its poor inflorescence stem quality seriously constrains the development of the cut flower. Mechanical strength is an important characteristic of stems, which not only affects plant lodging, but also plays an [...] Read more.

Herbaceous peony (Paeonia lactiflora Pall.) is a traditional famous flower, but its poor inflorescence stem quality seriously constrains the development of the cut flower. Mechanical strength is an important characteristic of stems, which not only affects plant lodging, but also plays an important role in stem bend or break. In this paper, the mechanical strength, morphological indices and microstructure of P. lactiflora development inflorescence stems were measured and observed. The results showed that the mechanical strength of inflorescence stems gradually increased, and that the diameter of inflorescence stem was a direct indicator in estimating mechanical strength. Simultaneously, with the development of inflorescence stem, the number of vascular bundles increased, the vascular bundle was arranged more densely, the sclerenchyma cell wall thickened, and the proportion of vascular bundle and pith also increased. On this basis, cellulose and lignin contents were determined, PlCesA3, PlCesA6 and PlCCoAOMT were isolated and their expression patterns were examined including PlPAL. The results showed that cellulose was not strictly correlated with the mechanical strength of inflorescence stem, and lignin had a significant impact on it. In addition, PlCesA3 and PlCesA6 were not key members in cellulose synthesis of P. lactiflora and their functions were also different, but PlPAL and PlCCoAOMT regulated the lignin synthesis of P. lactiflora. These data indicated that PlPAL and PlCCoAOMT could be applied to improve the mechanical strength of P. lactiflora inflorescence stem in genetic engineering. Full article

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Synthesis, Spectral and Antibacterial Studies of Copper(II) Tetraaza Macrocyclic Complexes

by Puchakayala Muralidhar Reddy, Rondla Rohini, Edulla Ravi Krishna, Anren Hu and Vadde Ravinder

Int. J. Mol. Sci. 2012, 13(4), 4982-4992; https://doi.org/10.3390/ijms13044982 - 19 Apr 2012

Cited by 40 | Viewed by 6946

Abstract

A novel family of tetraaza macrocyclic Cu(II) complexes [CuLX₂] (where L = N₄ donor macrocyclic ligands) and (X = Cl⁻, NO₃⁻) have been synthesized and characterized by elemental analysis, magnetic moments, IR, EPR, mass, electronic [...] Read more.

A novel family of tetraaza macrocyclic Cu(II) complexes [CuLX₂] (where L = N₄ donor macrocyclic ligands) and (X = Cl⁻, NO₃⁻) have been synthesized and characterized by elemental analysis, magnetic moments, IR, EPR, mass, electronic spectra and thermal studies. The magnetic moments and electronic spectral studies suggest square planar geometry for [Cu(DBACDT)]Cl₂ and [Cu(DBACDT)](NO₃)₂ complexes and distorted octahedral geometry to the rest of the ten complexes. The biological activity of all these complexes against gram-positive and gram-negative bacteria was compared with the activity of existing commercial antibacterial compounds like Linezolid and Cefaclor. Six complexes out of twelve were found to be most potent against both gram-positive as well as gram-negative bacteria due to the presence of thio group in the coordinated ligands. Full article

(This article belongs to the Section Materials Science)

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2-Decenoic Acid Ethyl Ester, a Compound That Elicits Neurotrophin-like Intracellular Signals, Facilitating Functional Recovery from Cerebral Infarction in Mice

by Yoshitaka Tanaka, Hidefumi Fukumitsu, Hitomi Soumiya, Shinichi Yoshimura, Toru Iwama and Shoei Furukawa

Int. J. Mol. Sci. 2012, 13(4), 4968-4981; https://doi.org/10.3390/ijms13044968 - 19 Apr 2012

Cited by 3 | Viewed by 6460

Abstract

In our previous study, we found that trans-2-decenoic acid ethyl ester (DAEE), a derivative of a medium-chain fatty acid, elicits neurotrophin-like signals including the activation of extracellular signal-regulated kinases 1 and 2 (ERK1/2) in cultured mouse cortical neurons. Here, we examined the efficacy [...] Read more.

In our previous study, we found that trans-2-decenoic acid ethyl ester (DAEE), a derivative of a medium-chain fatty acid, elicits neurotrophin-like signals including the activation of extracellular signal-regulated kinases 1 and 2 (ERK1/2) in cultured mouse cortical neurons. Here, we examined the efficacy of intraperitoneal administration of DAEE on the treatment of a mouse model of the cerebral infarction caused by unilateral permanent middle cerebral artery occlusion (PMCAO). DAEE-treatment (100 µg/kg body weight injected at 0.5, 24, 48, 72 h after PMCAO) significantly restored the mice from PMCAO-induced neurological deficits including motor paralysis when evaluated 48, 72, and 96 h after the PMCAO. Furthermore, DAEE facilitated the phosphorylation of ERK1/2 on the infarction side of the brain when analyzed by Western immunoblot analysis, and it enhanced the number of phosphorylated ERK1/2-positive cells in the border areas between the infarction and non-infarction regions of the cerebral cortex, as estimated immunohistochemically. As the infarct volume remained unchanged after DAEE-treatment, it is more likely that DAEE improved the neurological condition through enhanced neuronal functions of the remaining neurons in the damaged areas rather than by maintaining neuronal survival. These results suggest that DAEE has a neuro-protective effect on cerebral infarction. Full article

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Open AccessArticle

Mycoflora and Ochratoxin A Control in Wheat Grain Using Natural Extracts Obtained from Wine Industry By-Products

by Ersilia Alexa, Mariana-Atena Poiana and Renata-Maria Sumalan

Int. J. Mol. Sci. 2012, 13(4), 4949-4967; https://doi.org/10.3390/ijms13044949 - 19 Apr 2012

Cited by 15 | Viewed by 10164

Abstract

The aim of this study was to evaluate the effect of some natural extracts obtained from grape pomace (GPE) and grape seeds (GSE) as compared to a synthetic food, antioxidant-butylated hydroxytoluene (BHT), in order to control fungal population and ochratoxin A (OTA) production [...] Read more.

The aim of this study was to evaluate the effect of some natural extracts obtained from grape pomace (GPE) and grape seeds (GSE) as compared to a synthetic food, antioxidant-butylated hydroxytoluene (BHT), in order to control fungal population and ochratoxin A (OTA) production in naturally contaminated wheat. The results showed that the addition of these extracts was efficient with OTA content decreasing. On treatment with these extracts the loss of OTA content after 14 days was in the range 7.8–28.3% relative to the control sample, but increased up to 26.48–37% after 28 days. The highest loss in OTA content was recorded for treatment with GPE at the 500 ppm level. Regarding the fungal development, the obtained results show that the total fungal populations were significantly reduced by using natural extracts. The most efficient extract was GPE. Both BHT and GPE inhibit the growth of Penicillium verrrucosum, for all doses, but less with Aspergillus genera. GPE affects the growth of other types of moulds such as Rhizopus microsporus, Fusarium graminearum, Alternaria infectoria and Cladosporium herbarum. Our data suggested that GPE and GSE are able to provide fungicidal and fungistatic protection and to control the OTA accumulation in wheat, at least in a similar manner to BHT. Full article

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Open AccessArticle

Generation and Characterization of a Novel Recombinant Antibody Against 15-Ketocholestane Isolated by Phage-Display

by Md. Omedul Islam, Yan Ting Lim, Conrad En Zuo Chan, Amaury Cazenave-Gassiot, J. Ludovic Croxford, Markus R. Wenk, Paul A. Macary and Brendon J. Hanson

Int. J. Mol. Sci. 2012, 13(4), 4937-4948; https://doi.org/10.3390/ijms13044937 - 19 Apr 2012

Cited by 5 | Viewed by 7026

Abstract

The employment of monoclonal antibodies (Mabs) to identify disease-associated biomarkers in clinical samples represents the underlying principle for many diagnostic tests. To date, these have been principally developed for protein targets with few reported applications for lipids due to their hydrophobicity and poor [...] Read more.

The employment of monoclonal antibodies (Mabs) to identify disease-associated biomarkers in clinical samples represents the underlying principle for many diagnostic tests. To date, these have been principally developed for protein targets with few reported applications for lipids due to their hydrophobicity and poor immunogenicity. Oxysterols represent a family of lipids implicated in diverse human diseases where Mab-based detection assays could have a profound effect on their utility as clinical biomarkers. These are usually identified in patients’ samples by mass- spectrometry based approaches. Here, we describe an antibody phage-library based screening methodology for generating a recombinant monoclonal antibody (RAb) targeting the oxysterol-15-ketocholestane (15-KA), a lipid implicated in multiple sclerosis and Autoimmune Encephalomyelitis (EAE). The antibody is highly specific for 15-KA and shows little or no binding activity for other closely related oxysterols. We employ RAb2E9 to address the controversy over whether 15-KA is a true biomarker for MS/EAE and show that 15-KA is undetectable in serum taken from mice with EAE using antibody based detection methodologies; a finding confirmed by mass-spectrometry analysis. This study demonstrates the technical feasibility of using phage display to isolate highly specific antibodies against poorly immunogenic, small molecule lipids. Full article

(This article belongs to the Special Issue Phage Display)

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Structural and Functional Characterization of Two Alternative Splicing Variants of Mouse Endothelial Cell-Specific Chemotaxis Regulator (ECSCR)

by Wen Wu, Chunwei Shi, Fanxin Ma, James Balducci, Hanju Huang, Hong-Long Ji, Yongchang Chang and Yao Huang

Int. J. Mol. Sci. 2012, 13(4), 4920-4936; https://doi.org/10.3390/ijms13044920 - 19 Apr 2012

Cited by 6 | Viewed by 7734

Abstract

Endothelial cells (ECs) that line the lumen of blood vessels are important players in blood vessel formation, and EC migration is a key component of the angiogenic process. Thus, identification of genes that are specifically or preferentially expressed in vascular ECs and in-depth [...] Read more.

Endothelial cells (ECs) that line the lumen of blood vessels are important players in blood vessel formation, and EC migration is a key component of the angiogenic process. Thus, identification of genes that are specifically or preferentially expressed in vascular ECs and in-depth understanding of their biological functions may lead to discovery of new therapeutic targets. We have previously reported molecular characterization of human endothelial cell-specific molecule 2 (ECSM2)/endothelial cell-specific chemotaxis regulator (ECSCR). In the present study, we cloned two mouse full-length cDNAs by RT-PCR, which encode two putative ECSCR isoform precursors with considerable homology to the human ECSCR. Nucleotide sequence and exon-intron junction analyses suggested that they are alternative splicing variants (ECSCR isoform-1 and -2), differing from each other in the first and second exons. Quantitative RT-PCR results revealed that isoform-2 is the predominant form, which was most abundant in heart, lung, and muscles, and moderately abundant in uterus and testis. In contrast, the expression of isoform-1 seemed to be more enriched in testis. To further explore their potential cellular functions, we expressed GFP- and FLAG-tagged ECSCR isoforms, respectively, in an ECSCR deficient cell line (HEK293). Interestingly, the actual sizes of either ECSCR-GFP or -FLAG fusion proteins detected by immunoblotting are much larger than their predicted sizes, suggesting that both isoforms are glycoproteins. Fluorescence microscopy revealed that both ECSCR isoforms are localized at the cell surface, which is consistent with the structural prediction. Finally, we performed cell migration assays using mouse endothelial MS1 cells overexpressing GFP alone, isoform-1-GFP, and isoform-2-GFP, respectively. Our results showed that both isoforms significantly inhibited vascular epidermal growth factor (VEGF)-induced cell migration. Taken together, we have provided several lines of experimental evidence that two mouse ECSCR splicing variants/isoform precursors exist. They are differentially expressed in a variety of tissue types and likely involved in modulation of vascular EC migration. We have also defined the gene structure of mouse ECSCR using bioinformatics tools, which provides new information towards a better understanding of alternative splicing of ECSCR. Full article

(This article belongs to the Special Issue Hypothetical Proteins)

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Novel Drug Delivery System Based on Docetaxel-Loaded Nanocapsules as a Therapeutic Strategy Against Breast Cancer Cells

by Paola Sánchez-Moreno, Houria Boulaiz, Juan Luis Ortega-Vinuesa, José Manuel Peula-García and Antonia Aránega

Int. J. Mol. Sci. 2012, 13(4), 4906-4919; https://doi.org/10.3390/ijms13044906 - 19 Apr 2012

Cited by 43 | Viewed by 9668

Abstract

In the field of cancer therapy, lipid nanocapsules based on a core-shell structure are promising vehicles for the delivery of hydrophobic drugs such as docetaxel. The main aim of this work was to evaluate whether docetaxel-loaded lipid nanocapsules improved the anti-tumor effect of [...] Read more.

In the field of cancer therapy, lipid nanocapsules based on a core-shell structure are promising vehicles for the delivery of hydrophobic drugs such as docetaxel. The main aim of this work was to evaluate whether docetaxel-loaded lipid nanocapsules improved the anti-tumor effect of free docetaxel in breast cancer cells. Three docetaxel-loaded lipid nanocapsules were synthesized by solvent displacement method. Cytotoxic assays were evaluated in breast carcinoma (MCF-7) cells treated by the sulforhodamine B colorimetric method. Cell cycle was studied by flow cytometry and Annexin V-FITC, and apoptosis was evaluated by using propidium iodide assays. The anti-proliferative effect of docetaxel appeared much earlier when the drug was encapsulated in lipid nanoparticles than when it was free. Docetaxel-loaded lipid nanocapsules significantly enhanced the decrease in IC₅₀ rate, and the treated cells evidenced apoptosis and a premature progression of the cell cycle from G(1) to G(2)-M phase. The chemotherapeutic effect of free docetaxel on breast cancer cells is improved by its encapsulation in lipid nanocapsules. This approach has the potential to overcome some major limitations of conventional chemotherapy and may be a promising strategy for future applications in breast cancer therapy. Full article

(This article belongs to the Special Issue Nanotoxicology)

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Risk-Association of CYP11A1 Polymorphisms and Breast Cancer Among Han Chinese Women in Southern China

by Minying Sun, Xuexi Yang, Changsheng Ye, Weiwen Xu, Guangyu Yao, Jun Chen and Ming Li

Int. J. Mol. Sci. 2012, 13(4), 4896-4905; https://doi.org/10.3390/ijms13044896 - 18 Apr 2012

Cited by 11 | Viewed by 7227

Abstract

Exposure to endogenous sex hormones has been reported as a risk factor for breast cancer. The CYP11A1 gene encodes the key enzyme that catalyzes the initial and rate-limiting step in steroid hormone synthesis. In this study, the associations between single nucleotide polymorphisms (SNPs) [...] Read more.

Exposure to endogenous sex hormones has been reported as a risk factor for breast cancer. The CYP11A1 gene encodes the key enzyme that catalyzes the initial and rate-limiting step in steroid hormone synthesis. In this study, the associations between single nucleotide polymorphisms (SNPs) in CYP11A1 and breast cancer susceptibility were examined. Six SNPs in CYP11A1 were genotyped using the MassARRAY IPLEX platform in 530 breast cancer patients and 546 healthy controls. Association analyses based on a χ² test and binary logistic regression were performed to determine the odds ratio (OR) and 95% confidence interval (95% CI) for each SNP. Two loci (rs2959008 and rs2279357) showed evidence of associations with breast cancer risk. The variant genotype C/T-C/C of rs2959008 was significantly associated with a decreased risk (age-adjusted OR, 0.75; 95% CI, 0.58–0.96; P = 0.023) compared with the wild-type TT. However, the homozygous TT variant of rs2279357 exhibited increased susceptibility to breast cancer (age-adjusted OR, 1.44; 95% CI, 1.05–1.98; P = 0.022). The locus rs2959003 also showed an appreciable effect, but no associations were observed for three other SNPs. Our results suggest that polymorphisms of CYP11A1 are related to breast cancer susceptibility in Han Chinese women of South China. Full article

(This article belongs to the Section Biochemistry)

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Development of Eighteen Microsatellite Markers in Anemone amurensis (Ranunculaceae) and Cross-Amplification in Congeneric Species

by Mingzhou Sun, Xiao Yin, Fengxue Shi, Lin Li, Mingrui Li, Linfeng Li and Hongxing Xiao

Int. J. Mol. Sci. 2012, 13(4), 4889-4895; https://doi.org/10.3390/ijms13044889 - 18 Apr 2012

Cited by 2 | Viewed by 5642

Abstract

Polyploidy plays an important role in the evolution of plant genomes. To enable the investigation of the polyploidy events within the genus Anemone, we developed eighteen microsatellite markers from the hexaploid species A. amurensis (Ranunculaceae), and tested their transferability in five closely [...] Read more.

Polyploidy plays an important role in the evolution of plant genomes. To enable the investigation of the polyploidy events within the genus Anemone, we developed eighteen microsatellite markers from the hexaploid species A. amurensis (Ranunculaceae), and tested their transferability in five closely related species. The number of total alleles (N_A) for each resulting locus varied from one to eight. The polymorphism information content (PIC) and Nei’s genetic diversity (N_GD) for these microsatellites ranged from 0.00 to 0.71 and 0.00 to 0.91, respectively. For each population, the N_Awas one to seven, and the values of PIC and N_GD varied from 0.00 to 0.84 and 0.00 to 0.95, respectively. In addition, most of these microsatellites can be amplified successfully in the congeneric species. These microsatellite primers provide us an opportunity to study the polyploid evolution in the genus Anemone. Full article

(This article belongs to the Section Biochemistry)

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Study on the Immunomodulation Effect of Isodon japonicus Extract via Splenocyte Function and NK Anti-Tumor Activity

by Yu-Jin Hwang, Jaehyun Kim, Dong-Sik Park and Kyung-A Hwang

Int. J. Mol. Sci. 2012, 13(4), 4880-4888; https://doi.org/10.3390/ijms13044880 - 18 Apr 2012

Cited by 10 | Viewed by 6401

Abstract

Here we investigated the potential immune-enhancing activity of Isodon japonicus on murine splenocyte and natural-killer (NK) cells in vitro. The ethanol extract of I. japonicus significantly enhanced the proliferation of splenocyte and induced the significant enhancement of NK cells’ activity against [...] Read more.

Here we investigated the potential immune-enhancing activity of Isodon japonicus on murine splenocyte and natural-killer (NK) cells in vitro. The ethanol extract of I. japonicus significantly enhanced the proliferation of splenocyte and induced the significant enhancement of NK cells’ activity against tumor cells (YAC-1). In addition, I. japonicus increased the production of interferon (IFN)-γ and tumor necrosis factor (TNF)-α, suggesting that the increase in NK cell cytotoxicity could be due to the enhancement of the NK cell production of both cytokines. Taken together, I. japonicus extract inhibited the growth of human leukemia cells (K562) by 74%. Our observation indicated that the anti-tumor effects of I. japonicus may be attributed to its ability to serve as a stimulant of NK anti-tumor activity. In addition, our results support the development of functional food studies on I. japonicus. Full article

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Study of Drug Metabolism by Xanthine Oxidase

by Jing Zhao, Xiaolin He, Nana Yang, Lizhou Sun and Genxi Li

Int. J. Mol. Sci. 2012, 13(4), 4873-4879; https://doi.org/10.3390/ijms13044873 - 18 Apr 2012

Cited by 7 | Viewed by 6445

Abstract

In this work, we report the studies of drug metabolism by xanthine oxidase (XOD) with electrochemical techniques. Firstly, a pair of stable, well-defined and quasi-reversible oxidation/reduction peaks is obtained with the formal potential at −413.1 mV (vs. SCE) after embedding XOD in [...] Read more.

In this work, we report the studies of drug metabolism by xanthine oxidase (XOD) with electrochemical techniques. Firstly, a pair of stable, well-defined and quasi-reversible oxidation/reduction peaks is obtained with the formal potential at −413.1 mV (vs. SCE) after embedding XOD in salmon sperm DNA membrane on the surface of pyrolytic graphite electrode. Then, a new steady peak can be observed at −730 mV (vs. SCE) upon the addition of 6-mercaptopurine (6-MP) to the electrochemical system, indicating the metabolism of 6-MP by XOD. Furthermore, the chronoamperometric response shows that the current of the catalytic peak located at −730 mV increases with addition of 6-MP in a concentration-dependent manner, and the increase of the chronoamperometric current can be inhibited by an XOD inhibitor, quercetin. Therefore, our results prove that XOD/DNA modified electrode can be efficiently used to study the metabolism of 6-MP, which may provide a convenient approach for in vitro studies on enzyme-catalyzed drug metabolism. Full article

(This article belongs to the Section Biochemistry)

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Preparation, Characterization and Thermal Degradation of Polyimide (4-APS/BTDA)/SiO₂ Composite Films

by Mansor Bin Ahmad, Yadollah Gharayebi, Mohd. Sapuan Salit, Mohd. Zobir Hussein, Saeideh Ebrahimiasl and Arash Dehzangi

Int. J. Mol. Sci. 2012, 13(4), 4860-4872; https://doi.org/10.3390/ijms13044860 - 17 Apr 2012

Cited by 47 | Viewed by 10771

Abstract

Polyimide/SiO₂ composite films were prepared from tetraethoxysilane (TEOS) and poly(amic acid) (PAA) based on aromatic diamine (4-aminophenyl sulfone) (4-APS) and aromatic dianhydride (3,3,4,4-benzophenonetetracarboxylic dianhydride) (BTDA) via a sol-gel process in N-methyl-2-pyrrolidinone (NMP). The prepared polyimide/SiO₂ composite films were characterized using [...] Read more.

Polyimide/SiO₂ composite films were prepared from tetraethoxysilane (TEOS) and poly(amic acid) (PAA) based on aromatic diamine (4-aminophenyl sulfone) (4-APS) and aromatic dianhydride (3,3,4,4-benzophenonetetracarboxylic dianhydride) (BTDA) via a sol-gel process in N-methyl-2-pyrrolidinone (NMP). The prepared polyimide/SiO₂ composite films were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and thermogravimetric analysis (TGA). The FTIR results conﬁrmed the synthesis of polyimide (4-APS/BTDA) and the formation of SiO₂ particles in the polyimide matrix. Meanwhile, the SEM images showed that the SiO₂particles were well dispersed in the polyimide matrix. Thermal stability and kinetic parameters of the degradation processes for the prepared polyimide/SiO₂ composite films were investigated using TGA in N₂ atmosphere. The activation energy of the solid-state process was calculated using Flynn–Wall–Ozawa’s method without the knowledge of the reaction mechanism. The results indicated that thermal stability and the values of the calculated activation energies increased with the increase of the TEOS loading and the activation energy also varied with the percentage of weight loss for all compositions. Full article

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Int. J. Mol. Sci., Volume 13, Issue 4 (April 2012) – 83 articles , Pages 4003-5289

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