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Int. J. Mol. Sci., Volume 11, Issue 7 (July 2010), Pages 2584-2779

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Research

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Open AccessArticle Sequential Events in the Irreversible Thermal Denaturation of Human Brain-Type Creatine Kinase by Spectroscopic Methods
Int. J. Mol. Sci. 2010, 11(7), 2584-2596; doi:10.3390/ijms11072584
Received: 21 May 2010 / Revised: 9 June 2010 / Accepted: 18 June 2010 / Published: 25 June 2010
Cited by 7 | PDF Full-text (1239 KB) | HTML Full-text | XML Full-text
Abstract
The non-cooperative or sequential events which occur during protein thermal denaturation are closely correlated with protein folding, stability, and physiological functions. In this research, the sequential events of human brain-type creatine kinase (hBBCK) thermal denaturation were studied by differential scanning calorimetry (DSC), [...] Read more.
The non-cooperative or sequential events which occur during protein thermal denaturation are closely correlated with protein folding, stability, and physiological functions. In this research, the sequential events of human brain-type creatine kinase (hBBCK) thermal denaturation were studied by differential scanning calorimetry (DSC), CD, and intrinsic fluorescence spectroscopy. DSC experiments revealed that the thermal denaturation of hBBCK was calorimetrically irreversible. The existence of several endothermic peaks suggested that the denaturation involved stepwise conformational changes, which were further verified by the discrepancy in the transition curves obtained from various spectroscopic probes. During heating, the disruption of the active site structure occurred prior to the secondary and tertiary structural changes. The thermal unfolding and aggregation of hBBCK was found to occur through sequential events. This is quite different from that of muscle-type CK (MMCK). The results herein suggest that BBCK and MMCK undergo quite dissimilar thermal unfolding pathways, although they are highly conserved in the primary and tertiary structures. A minor difference in structure might endow the isoenzymes dissimilar local stabilities in structure, which further contribute to isoenzyme-specific thermal stabilities. Full article
(This article belongs to the Section Biochemistry, Molecular Biology and Biophysics)
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Open AccessArticle Analysis of the Nucleophilic Solvation Effects in Isopropyl Chlorothioformate Solvolysis
Int. J. Mol. Sci. 2010, 11(7), 2597-2611; doi:10.3390/ijms11072597
Received: 9 June 2010 / Revised: 21 June 2010 / Accepted: 28 June 2010 / Published: 29 June 2010
Cited by 10 | PDF Full-text (223 KB) | HTML Full-text | XML Full-text
Abstract
Correlation of the solvent effects through application of the extended Grunwald-Winstein equation to the solvolysis of isopropyl chlorothioformate results in a sensitivity value of 0.38 towards changes in solvent nucleophilicity (l) and a sensitivity value of 0.72 towards changes in [...] Read more.
Correlation of the solvent effects through application of the extended Grunwald-Winstein equation to the solvolysis of isopropyl chlorothioformate results in a sensitivity value of 0.38 towards changes in solvent nucleophilicity (l) and a sensitivity value of 0.72 towards changes in solvent ionizing power (m). This tangible l value coupled with the negative entropies of activation observed indicates a favorable predisposition towards a modest rear-side nucleophilic solvation of a developing carbocation. Only in 100% ethanol was the bimolecular pathway dominant. These observations are very different from those obtained for the solvolysis of isopropyl chloroformate, where dual reaction channels were proposed, with the addition-elimination reaction favored in the more nucleophilic solvents and a unimolecular fragmentation-ionization mechanism favored in the highly ionizing solvents. Full article
(This article belongs to the Section Physical Chemistry, Theoretical and Computational Chemistry)
Open AccessArticle Antibiotic Producing Potentials of Three Freshwater Actinomycetes Isolated from the Eastern Cape Province of South Africa
Int. J. Mol. Sci. 2010, 11(7), 2612-2623; doi:10.3390/ijms11072612
Received: 10 June 2010 / Revised: 25 June 2010 / Accepted: 28 June 2010 / Published: 2 July 2010
Cited by 9 | PDF Full-text (75 KB) | HTML Full-text | XML Full-text
Abstract
Crude extracts of three actinomycetes species belonging to Saccharopolyspora (TR 046 and TR 039) and Actinosynnema (TR 024) genera were screened for antibacterial activities against a panel of several bacterial strains. The extracts showed antibacterial activities against both gram-negative and gram-positive test [...] Read more.
Crude extracts of three actinomycetes species belonging to Saccharopolyspora (TR 046 and TR 039) and Actinosynnema (TR 024) genera were screened for antibacterial activities against a panel of several bacterial strains. The extracts showed antibacterial activities against both gram-negative and gram-positive test bacteria with inhibition zones ranging from 8 to 28 mm (TR 046); 8 to15 mm (TR 039); and 10 to 13 mm (TR 024). The minimum inhibitory concentrations ranged from 0.078 to 10 mg/mL (TR 046); 5 to >10 mg/mL (TR 039); and 1.25 to 5 mg/mL (TR 024). Time-kill studies revealed that crude extract of TR 046 showed strong bactericidal activity against Bacillus pumilus (ATCC14884), reducing the bacterial load by 104 cfu/mL and 102 cfu/mL at 4× MIC and 2× MIC, respectively, after 6 h of exposure. Similarly, against Proteus vulgaris (CSIR 0030), crude extract of TR 046 achieved a 0.9log10 and 0.13log10 cfu/mL reduction at 5 mg/mL (4× MIC) and 1.25 mg/mL (2× MIC) after 12 h of exposure. The extract was however weakly bactericidal against two environmental bacterial strains (Klebsiella pneumoniae and Staphylococcus epidermidis); and against Pseudomonas aeruginosa (ATCC 19582): the extract showed bacteriostatic activities at all concentrations tested. These freshwater actinomycetes appear to have immense potential as a source of new antibacterial compound(s). Full article
(This article belongs to the Section Biochemistry, Molecular Biology and Biophysics)
Open AccessArticle Decreased Erythrocyte CCS Content is a Biomarker of Copper Overload in Rats
Int. J. Mol. Sci. 2010, 11(7), 2624-2635; doi:10.3390/ijms11072624
Received: 26 May 2010 / Revised: 25 June 2010 / Accepted: 30 June 2010 / Published: 2 July 2010
Cited by 3 | PDF Full-text (81 KB) | HTML Full-text | XML Full-text
Abstract
Copper (Cu)is an essential trace metal that is toxic in excess. It is therefore important to be able to accurately assess Cu deficiency or overload. Cu chaperone for Cu/Zn superoxide dismutase (CCS) protein expression is elevated in tissues of Cu-deficient animals. Increased CCS content in erythrocytes is particularly sensitive to decreased Cu status. Given the lack of a non-invasive, sensitive and specific biomarker for the assessment of Cu excess, we investigated whether CCS expression in erythrocytes reflects Cu overload. Rats were fed diets containing normal or high levels of Cu for 13 weeks. Diets contained 6.3 ± 0.6 (Cu-N), 985 ± 14 (Cu-1000) or 1944 ± 19 (Cu-2000) mg Cu/kg diet. Rats showed a variable response to the high Cu diets. Some rats showed severe Cu toxicity, while other rats showed no visible signs of toxicity and grew normally. Also, some rats had high levels of Cu in liver, whereas others had liver Cu concentrations within the normal range. Erythrocyte CCS protein expression was 30% lower in Cu-2000 rats compared to Cu-N rats (P < 0.05). Notably, only rats that accumulated high levels of Cu in liver had lower erythrocyte CCS (47% reduction, P < 0.05) compared to rats fed normal levels of Cu. Together, these data indicate that decreased erythrocyte CCS content is associated with Cu overload in rats and should be evaluated further as a potential biomarker for assessing Cu excess in humans. Full article
(This article belongs to the Special Issue Biomarkers)
Open AccessArticle The Effect of Treadmill Training Pre-Exercise on Glutamate Receptor Expression in Rats after Cerebral Ischemia
Int. J. Mol. Sci. 2010, 11(7), 2658-2669; doi:10.3390/ijms11072658
Received: 4 June 2010 / Revised: 2 July 2010 / Accepted: 2 July 2010 / Published: 7 July 2010
Cited by 19 | PDF Full-text (474 KB) | HTML Full-text | XML Full-text
Abstract
Physical exercise has been demonstrated to be neuroprotective in both clinical and laboratory settings. However, the exact mechanism underlying this effect is unclear. Our study aimed to investigate whether pre-ischemic treadmill training could serve as a form of ischemic preconditioning in a [...] Read more.
Physical exercise has been demonstrated to be neuroprotective in both clinical and laboratory settings. However, the exact mechanism underlying this effect is unclear. Our study aimed to investigate whether pre-ischemic treadmill training could serve as a form of ischemic preconditioning in a rat model undergoing middle cerebral artery occlusion (MCAO). Thirty-six rats were divided into three groups: a sham control group, a non-exercise with operation group and an exercise with operation group. After treadmill training, ischemia was induced by occluding the MCA for 2 h, followed by reperfusion. Half of the rats in each group were sacrificed for mRNA detection of mGluR5 and NR2B 80 min after occlusion. The remaining animals were evaluated for neurological deficits by behavioral scoring and then decapitated to assess the infarct volume. The mRNA expression of mGluR5 and NR2B was detected by real-time PCR. The results suggest that pre-ischemic treadmill training may induce brain ischemic tolerance by reducing the mRNA levels of mGluR5 and NR2B, and thus, the results indicate that physical exercise might be an effective method to establish ischemic preconditioning. Full article
(This article belongs to the Special Issue Neuroprotective Strategies (special issue))
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Open AccessArticle Molecular Epidemiological Study of Pyrazinamide-Resistance in Clinical Isolates of Mycobacterium tuberculosis from South India
Int. J. Mol. Sci. 2010, 11(7), 2670-2680; doi:10.3390/ijms11072670
Received: 18 May 2010 / Accepted: 24 May 2010 / Published: 7 July 2010
Cited by 13 | PDF Full-text (154 KB) | HTML Full-text | XML Full-text
Abstract
Pyrazinamide (PZA) has been in use for almost 50 years as a first-line drug for short-course chemotherapy against Mycobacterium tuberculosis. In this study, PCR mediated automated DNA sequencing is used to check the prevalence of PZA resistance among treatment failure cases [...] Read more.
Pyrazinamide (PZA) has been in use for almost 50 years as a first-line drug for short-course chemotherapy against Mycobacterium tuberculosis. In this study, PCR mediated automated DNA sequencing is used to check the prevalence of PZA resistance among treatment failure cases of pulmonary tuberculosis. Out of 50 clinical isolates examined, 39 had mutations in the pncA gene that encodes Pyrazinamidase, an enzyme required to activate PZA. Of these, 31 (79.5%) were localized to three regions of pncA. We found two isolates with hitherto unreported mutation at amino acid 26 (Ala→Gly) of pncA. Full article
(This article belongs to the Section Biochemistry, Molecular Biology and Biophysics)
Open AccessArticle Principal Component Analysis of HPLC Retention Data and Molecular Modeling Structural Parameters of Cardiovascular System Drugs in View of Their Pharmacological Activity
Int. J. Mol. Sci. 2010, 11(7), 2681-2698; doi:10.3390/ijms11072681
Received: 22 April 2010 / Revised: 11 June 2010 / Accepted: 28 June 2010 / Published: 9 July 2010
Cited by 7 | PDF Full-text (372 KB) | HTML Full-text | XML Full-text
Abstract
Evaluation of relationships between molecular modeling structural parameters and high-performance liquid chromatography (HPLC) retention data of 11 cardiovascular system drugs by principal component analysis (PCA) in relation to their pharmacological activity was performed. The six retention data parameters were determined on three [...] Read more.
Evaluation of relationships between molecular modeling structural parameters and high-performance liquid chromatography (HPLC) retention data of 11 cardiovascular system drugs by principal component analysis (PCA) in relation to their pharmacological activity was performed. The six retention data parameters were determined on three different HPLC columns (Nucleosil C18 AB with octadecylsilica stationary phase, IAM PC C10/C3 with chemically bounded phosphatidylcholine, and Nucleosil 100-5 OH with chemically bounded propanodiole), and using isocratically acetonitrile: Britton-Robinson buffer as the mobile phase. Additionally, molecular modeling studies were performed with the use of HyperChem software and MM+ molecular mechanics with the semi-empirical AM1 method deriving 20 structural descriptors. Factor analysis obtained with the use of various sets of parameters: structural parameters, HPLC retention data, and all 26 considered parameters, led to the extraction of two main factors. The first principal component (factor 1) accounted for 44-57% of the variance in the data. The second principal component (factor 2) explained 29-33% of data variance. Moreover, the total data variance explained by the first two factors was at the level of 73-90%. More importantly, the PCA analysis of the HPLC retention data and structural parameters allows the segregation of circulatory system drugs according to their pharmacological (cardiovascular) properties as shown by the distribution of the individual drugs on the plane determined by the two principal components (factors 1 and 2). Full article
(This article belongs to the Section Biochemistry, Molecular Biology and Biophysics)
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Open AccessArticle Biomass Thermogravimetric Analysis: Uncertainty Determination Methodology and Sampling Maps Generation
Int. J. Mol. Sci. 2010, 11(7), 2701-2714; doi:10.3390/ijms11072701
Received: 3 June 2010 / Revised: 5 July 2010 / Accepted: 11 July 2010 / Published: 15 July 2010
Cited by 5 | PDF Full-text (263 KB) | HTML Full-text | XML Full-text
Abstract
The objective of this study was to develop a methodology for the determination of the maximum sampling error and confidence intervals of thermal properties obtained from thermogravimetric analysis (TG), including moisture, volatile matter, fixed carbon and ash content. The sampling procedure of [...] Read more.
The objective of this study was to develop a methodology for the determination of the maximum sampling error and confidence intervals of thermal properties obtained from thermogravimetric analysis (TG), including moisture, volatile matter, fixed carbon and ash content. The sampling procedure of the TG analysis was of particular interest and was conducted with care. The results of the present study were compared to those of a prompt analysis, and a correlation between the mean values and maximum sampling errors of the methods were not observed. In general, low and acceptable levels of uncertainty and error were obtained, demonstrating that the properties evaluated by TG analysis were representative of the overall fuel composition. The accurate determination of the thermal properties of biomass with precise confidence intervals is of particular interest in energetic biomass applications. Full article
(This article belongs to the Section Green Chemistry)
Open AccessArticle Anti-Allergic Activity of a Platycodon Root Ethanol Extract
Int. J. Mol. Sci. 2010, 11(7), 2746-2758; doi:10.3390/ijms11072746
Received: 21 May 2010 / Revised: 30 June 2010 / Accepted: 6 July 2010 / Published: 16 July 2010
Cited by 10 | PDF Full-text (328 KB) | HTML Full-text | XML Full-text
Abstract
Platycodon grandiflorum (Campanulaceae) is used as traditional medicine in Asian countries. In Korean traditional medicine, Platycodon root has been widely used since ancient times as a traditional drug to treat cold, cough and asthma. However, its effects on bone marrow-derived mast cell [...] Read more.
Platycodon grandiflorum (Campanulaceae) is used as traditional medicine in Asian countries. In Korean traditional medicine, Platycodon root has been widely used since ancient times as a traditional drug to treat cold, cough and asthma. However, its effects on bone marrow-derived mast cell (BMMC)-mediated allergy and inflammation mechanisms remain unknown. In this study, the biological effect of Platycodon root ethanol extract (PE) was evaluated in BMMC after induction of allergic mediators by phorbol 12-myristate 13-acetate (PMA) plus calcium ionophore A23187 (A23187) stimulation. The effect of PE on the production of several allergic mediators, such as interleukin-6 (IL-6), prostaglandin D2 (PGD2), leukotriene C4 (LTC4), β-Hexosaminidase (β-Hex) and cyclooxygenase-2 (COX-2) protein, was investigated. The results demonstrate that PE inhibits PMA + A23187 induced production of IL-6, PGD2, LTC4, β-Hexosaminidase and COX-2 protein. Taken together, these results indicate that PE has the potential for use in the treatment of allergy. Full article
(This article belongs to the Section Biochemistry, Molecular Biology and Biophysics)
Open AccessArticle Crystallisation of Wild-Type and Variant Forms of a Recombinant Plant Enzyme β-D-Glucan Glucohydrolase from Barley (Hordeum vulgare L.) and Preliminary X-ray Analysis
Int. J. Mol. Sci. 2010, 11(7), 2759-2769; doi:10.3390/ijms11072759
Received: 28 May 2010 / Revised: 16 July 2010 / Accepted: 16 July 2010 / Published: 19 July 2010
PDF Full-text (4196 KB) | HTML Full-text | XML Full-text
Abstract
Wild-type and variant crystals of a recombinant enzyme β-d-glucan glucohydrolase from barley (Hordeum vulgare L.) were obtained by macroseeding and cross-seeding with microcrystals obtained from native plant protein. Crystals grew to dimensions of up to 500 x 250 x [...] Read more.
Wild-type and variant crystals of a recombinant enzyme β-d-glucan glucohydrolase from barley (Hordeum vulgare L.) were obtained by macroseeding and cross-seeding with microcrystals obtained from native plant protein. Crystals grew to dimensions of up to 500 x 250 x 375 µm at 277 K in the hanging-drops by vapour-diffusion. Further, the conditions are described that yielded the wild-type crystals with dimensions of 80 x 40 x 60 µm by self-nucleation vapour-diffusion in sitting-drops at 281 K. The wild-type and recombinant crystals prepared by seeding techniques achieved full size within 5-14 days, while the wild-type crystals grown by self-nucleation appeared after 30 days and reached their maximum size after another two months. Both the wild-type and recombinant variant crystals, the latter altered in the key catalytic and substrate-binding residues Glu220, Trp434 and Arg158/Glu161 belonged to the P43212 tetragonal space group, i.e., the space group of the native microcrystals was retained in the newly grown recombinant crystals. The crystals diffracted beyond 1.57-1.95 Å and the cell dimensions were between a = b = 99.2-100.8 Å and c = 183.2-183.6 Å. With one molecule in the asymmetric unit, the calculated Matthews coefficients were between 3.4-3.5 Å3.Da-1 and the solvent contents varied between 63.4% and 64.5%. The macroseeding and cross-seeding techniques are advantageous, where a limited amount of variant proteins precludes screening of crystallisation conditions, or where variant proteins could not be crystallized. Full article
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Open AccessArticle Reactivity of Heteropolytungstate and Heteropolymolybdate Metal Transition Salts in the Synthesis of Dimethyl Carbonate from Methanol and CO2
Int. J. Mol. Sci. 2010, 11(7), 2770-2779; doi:10.3390/ijms11072770
Received: 24 May 2010 / Revised: 24 June 2010 / Accepted: 12 July 2010 / Published: 23 July 2010
Cited by 10 | PDF Full-text (226 KB) | HTML Full-text | XML Full-text
Abstract
A series of Keggin-type heteropoly compounds (HPC) having different countercations (Co, Fe) and different addenda atoms (W, Mo) were synthesized and characterized by means of Fourier-Transform Infrared Spectrometer (FT-IR) and X-ray powder diffraction (XRD). The catalytic properties of the prepared catalysts for [...] Read more.
A series of Keggin-type heteropoly compounds (HPC) having different countercations (Co, Fe) and different addenda atoms (W, Mo) were synthesized and characterized by means of Fourier-Transform Infrared Spectrometer (FT-IR) and X-ray powder diffraction (XRD). The catalytic properties of the prepared catalysts for the dimethyl carbonate (DMC) synthesis from CO2 and CH3OH were investigated. The experimental results showed that the catalytic activity is significantly influenced by the type of the countercation and addenda atoms transition metal. Among the catalysts examined, Co1.5PW12O40 is the most active for the DMC synthesis, owing to the synergetic effect between Co and W. Investigating the effect of the support showed that the least acidic one (Al2O3) enhanced the conversion but decreased the DMC selectivity in favor of that of methyl formate (MF), while that of dimethoxy methane remained stable. Full article
(This article belongs to the Section Physical Chemistry, Theoretical and Computational Chemistry)

Review

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Open AccessReview Conducting Polymer Nanostructures: Template Synthesis and Applications in Energy Storage
Int. J. Mol. Sci. 2010, 11(7), 2636-2657; doi:10.3390/ijms11072636
Received: 12 May 2010 / Revised: 29 May 2010 / Accepted: 17 June 2010 / Published: 2 July 2010
Cited by 100 | PDF Full-text (1828 KB) | HTML Full-text | XML Full-text
Abstract
Conducting polymer nanostructures have received increasing attention in both fundamental research and various application fields in recent decades. Compared with bulk conducting polymers, conducting polymer nanostructures are expected to display improved performance in energy storage because of the unique properties arising from [...] Read more.
Conducting polymer nanostructures have received increasing attention in both fundamental research and various application fields in recent decades. Compared with bulk conducting polymers, conducting polymer nanostructures are expected to display improved performance in energy storage because of the unique properties arising from their nanoscaled size: high electrical conductivity, large surface area, short path lengths for the transport of ions, and high electrochemical activity. Template methods are emerging for a sort of facile, efficient, and highly controllable synthesis of conducting polymer nanostructures. This paper reviews template synthesis routes for conducting polymer nanostructures, including soft and hard template methods, as well as its mechanisms. The application of conducting polymer mesostructures in energy storage devices, such as supercapacitors and rechargeable batteries, are discussed. Full article
(This article belongs to the Special Issue Conjugated Polymers)
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Open AccessReview Nitric Oxide: Perspectives and Emerging Studies of a Well Known Cytotoxin
Int. J. Mol. Sci. 2010, 11(7), 2715-2745; doi:10.3390/ijms11072715
Received: 26 May 2010 / Revised: 17 June 2010 / Accepted: 13 July 2010 / Published: 16 July 2010
Cited by 30 | PDF Full-text (545 KB) | HTML Full-text | XML Full-text
Abstract
The free radical nitric oxide (NO) is known to play a dual role in human physiology and pathophysiology. At low levels, NOcan protect cells; however, at higher levels, NOis a known cytotoxin, having been implicated in [...] Read more.
The free radical nitric oxide (NO) is known to play a dual role in human physiology and pathophysiology. At low levels, NOcan protect cells; however, at higher levels, NOis a known cytotoxin, having been implicated in tumor angiogenesis and progression. While the majority of research devoted to understanding the role of NOin cancer has to date been tissue-specific, we herein review underlying commonalities of NOwhich may well exist among tumors arising from a variety of different sites. We also discuss the role of NOin human physiology and pathophysiology, including the very important relationship between NOand the glutathione-transferases, a class of protective enzymes involved in cellular protection. The emerging role of NOin three main areas of epigenetics—DNA methylation, microRNAs, and histone modifications—is then discussed. Finally, we describe the recent development of a model cell line system in which human tumor cell lines were adapted to high NO (HNO) levels. We anticipate that these HNO cell lines will serve as a useful tool in the ongoing efforts to better understand the role of NOin cancer. Full article
(This article belongs to the Special Issue Advances in Molecular Toxicology)
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Other

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Open AccessAddendum Addendum: Quasi-Drugs Developed in Japan for the Prevention or Treatment of Hyperpigmentary Disorders. Int. J. Mol. Sci. 2010, 11, 2566–2575
Int. J. Mol. Sci. 2010, 11(7), 2699-2700; doi:10.3390/ijms11072699
Received: 5 July 2010 / Accepted: 8 July 2010 / Published: 12 July 2010
PDF Full-text (23 KB) | HTML Full-text | XML Full-text
Abstract One additional skin lightening or whitening quasi-drug (QD) has been developed and officially approved by the Ministry of Health, Labor and Welfare of Japan. Full article

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