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Int. J. Mol. Sci., Volume 11, Issue 12 (December 2010), Pages 4782-5347

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Open AccessArticle Mouse Plasminogen Has Oxidized Phosphatidylcholine Adducts That Are Not Metabolized by Lipoprotein-Associated Phospholipase A2 under Basal Conditions
Int. J. Mol. Sci. 2010, 11(12), 5339-5347; https://doi.org/10.3390/ijms11125339
Received: 12 November 2010 / Revised: 15 December 2010 / Accepted: 17 December 2010 / Published: 22 December 2010
Cited by 1 | PDF Full-text (263 KB) | HTML Full-text | XML Full-text
Abstract
We previously showed that plasminogen (Plg) isolated from the plasma of normal human subjects contains 1–2 moles of oxidized phosphatidylcholine (oxPtdPC) adducts/mole of protein. Moreover, we suggested that these species are generated at the hepatic site and speculated that they may play a
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We previously showed that plasminogen (Plg) isolated from the plasma of normal human subjects contains 1–2 moles of oxidized phosphatidylcholine (oxPtdPC) adducts/mole of protein. Moreover, we suggested that these species are generated at the hepatic site and speculated that they may play a role in the reported cardiovascular pathogenicity of Plg. We aimed to determine whether mouse Plg also harbors linked oxPtdPCs and whether these molecules are metabolized by lipoprotein-associated phospholipase A2/PAF acetylhydrolase (Lp-PLA2/PAF-AH), an enzyme specific for hydrolysis of oxPtdPCs. We determined the total concentration of Plg in plasma samples from control (WT) and Lp-PLA2-deficient (KO) mice, we isolated Plg, and assessed its content of oxPtdPCs by immunoblot analyses. We also evaluated whether human recombinant Lp-PLA2 metabolized Plg-linked oxPtdPCs in vivo and in vitro. WT and KO mice expressed comparable levels (14.4–15.8 mg/dL) of plasma Plg, as determined by ELISA. We observed no differences in the content of oxPtdPC in Plg isolated from the two mouse strains and in parallel no changes in oxPtdPC content in mouse Plg following incubation with pure recombinant Lp-PLA2. Plg from mouse plasma contains oxPtdPC adducts that are not affected by the action of Lp-PLA2, suggesting that linkage to Plg protects oxPtdPCs from metabolism during their transport in the plasma. This modification may have important physio-pathological implications related to the function of Plg, oxPtdPCs, or both. Full article
(This article belongs to the Special Issue Phospholipids: Molecular Sciences)
Open AccessArticle Antiproliferative Effects of Cucurbitacin B in Breast Cancer Cells: Down-Regulation of the c-Myc/hTERT/Telomerase Pathway and Obstruction of the Cell Cycle
Int. J. Mol. Sci. 2010, 11(12), 5323-5338; https://doi.org/10.3390/ijms11125323
Received: 19 November 2010 / Revised: 20 December 2010 / Accepted: 21 December 2010 / Published: 22 December 2010
Cited by 31 | PDF Full-text (648 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Naturally occurring cucurbitacins have been shown to have anticancer, antimicrobial and anti-inflammatory activities. In this study, we determined the effects of cucurbitacin B extracted from the Thai herb Trichosanthes cucumerina L. on telomerase regulation in three human breast cancer cell lines (T47D, SKBR-3,
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Naturally occurring cucurbitacins have been shown to have anticancer, antimicrobial and anti-inflammatory activities. In this study, we determined the effects of cucurbitacin B extracted from the Thai herb Trichosanthes cucumerina L. on telomerase regulation in three human breast cancer cell lines (T47D, SKBR-3, and MCF-7) and a mammary epithelium cell line (HBL-100). Cell viability after treatment with cucurbitacin B, which is an active ingredient of this herb, was assessed. Telomeric Repeat Amplification Protocol (TRAP) assays and RT-PCR (qualitative and realtime) were performed to investigate activity of telomerase as well as expression of human telomerase reverse transcriptase (hTERT) and c-Myc. The c-Myc protein level was also determined in SKBR-3 and HBL-100 cells. Our results show that the cucurbitacin B inhibits growth and telomerase activity in the three breast cancer cell lines and exerts an obvious inhibitory effect in the estrogen receptor (ER)-negative breast cancer SKBR-3 cells. The expression of hTERT and c-Myc were also inhibited by cucurbitacin B, In addition, a clear reduction of c-Myc protein was observed after treatment in SKBR-3 cells even with a concentration of cucurbitacin B that was ten-times lower compared to the concentration used for HBL-100. Our findings imply that cucurbitacin B exerts an anticancer effect by inhibiting telomerase via down regulating both the hTERT and c-Myc expression in breast cancer cells. Full article
(This article belongs to the Section Biochemistry, Molecular and Cellular Biology)
Open AccessArticle Chronic Mild Stress Induces Fluoxetine-Reversible Decreases in Hippocampal and Cerebrospinal Fluid Levels of the Neurotrophic Factor S100B and Its Specific Receptor
Int. J. Mol. Sci. 2010, 11(12), 5310-5322; https://doi.org/10.3390/ijms11125310
Received: 8 November 2010 / Revised: 3 December 2010 / Accepted: 18 December 2010 / Published: 21 December 2010
Cited by 21 | PDF Full-text (275 KB) | HTML Full-text | XML Full-text
Abstract
Chronic mild stress (CMS) affects the hippocampal structure and function in the rat. S100B, a calcium-binding protein secreted by astrocytes, has been shown to be increased in serum of patients with depression and associated with good therapeutic response and clinical outcome. This work
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Chronic mild stress (CMS) affects the hippocampal structure and function in the rat. S100B, a calcium-binding protein secreted by astrocytes, has been shown to be increased in serum of patients with depression and associated with good therapeutic response and clinical outcome. This work aimed to study the impact of CMS and fluoxetine on depressive-like behaviors in rats, as well as the concomitant expression of the astroglial protein S100B and of its receptor RAGE (receptor for advanced glycation end products) in the hippocampus and Cerebrospinal fluid of the same group of animals. S100B and sRAGE (circulating soluble form of RAGE) were measured in CSF by ELISA, and S100B and RAGE were measured in hippocampal slices by Western blot. Our study has demonstrated that stress and depression decrease S100B and RAGE/SRAGE expression and antidepressant treatment reverses or blocks these effects. This result suggested that S100B/RAGE interactions may be involved in the development and maintenance of depression and may play an important role in the mechanism of antidepressants’ therapeutic action. Full article
(This article belongs to the Section Biochemistry, Molecular and Cellular Biology)
Open AccessReview Intrinsically Disordered Proteins in a Physics-Based World
Int. J. Mol. Sci. 2010, 11(12), 5292-5309; https://doi.org/10.3390/ijms11125292
Received: 19 October 2010 / Revised: 17 December 2010 / Accepted: 17 December 2010 / Published: 21 December 2010
Cited by 28 | PDF Full-text (203 KB) | HTML Full-text | XML Full-text
Abstract
Intrinsically disordered proteins (IDPs) are a newly recognized class of functional proteins that rely on a lack of stable structure for function. They are highly prevalent in biology, play fundamental roles, and are extensively involved in human diseases. For signaling and regulation, IDPs
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Intrinsically disordered proteins (IDPs) are a newly recognized class of functional proteins that rely on a lack of stable structure for function. They are highly prevalent in biology, play fundamental roles, and are extensively involved in human diseases. For signaling and regulation, IDPs often fold into stable structures upon binding to specific targets. The mechanisms of these coupled binding and folding processes are of significant importance because they underlie the organization of regulatory networks that dictate various aspects of cellular decision-making. This review first discusses the challenge in detailed experimental characterization of these heterogeneous and dynamics proteins and the unique and exciting opportunity for physics-based modeling to make crucial contributions, and then summarizes key lessons from recent de novo simulations of the structure and interactions of several regulatory IDPs. Full article
(This article belongs to the Special Issue Advances in Molecular Recognition)
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Open AccessArticle Screening of Molecular Virulence Markers in Staphylococcus aureus and Pseudomonas aeruginosa Strains Isolated from Clinical Infections
Int. J. Mol. Sci. 2010, 11(12), 5273-5291; https://doi.org/10.3390/ijms11125273
Received: 12 November 2010 / Revised: 2 December 2010 / Accepted: 3 December 2010 / Published: 21 December 2010
Cited by 20 | PDF Full-text (538 KB) | HTML Full-text | XML Full-text
Abstract
Staphylococcus (S.) aureus and Pseudomonas (Ps.) aeruginosa are two of the most frequently opportunistic pathogens isolated in nosocomial infections, responsible for severe infections in immunocompromised hosts. The frequent emergence of antibiotic-resistant S. aureus and Ps. aeruginosa strains has determined the development of new
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Staphylococcus (S.) aureus and Pseudomonas (Ps.) aeruginosa are two of the most frequently opportunistic pathogens isolated in nosocomial infections, responsible for severe infections in immunocompromised hosts. The frequent emergence of antibiotic-resistant S. aureus and Ps. aeruginosa strains has determined the development of new strategies in order to elucidate the different mechanisms used by these bacteria at different stages of the infectious process, providing the scientists with new procedures for preventing, or at least improving, the control of S. aureus and Ps. aeruginosa infections. The purpose of this study was to characterize the molecular markers of virulence in S. aureus and Ps. aeruginosa strains isolated from different clinical specimens. We used multiplex and uniplex PCR assays to detect the genes encoding different cell-wall associated and extracellular virulence factors, in order to evaluate potential associations between the presence of putative virulence genes and the outcome of infections caused by these bacteria. Our results demonstrate that all the studied S. aureus and Ps. aeruginosa strains synthesize the majority of the investigated virulence determinants, probably responsible for different types of infections. Full article
(This article belongs to the Special Issue Advances in Molecular Diagnostics)
Open AccessArticle In Vitro Response of Retinal Pigment Epithelial Cells Exposed to Chitosan Materials Prepared with Different Cross-Linkers
Int. J. Mol. Sci. 2010, 11(12), 5256-5272; https://doi.org/10.3390/ijms11125256
Received: 18 November 2010 / Revised: 13 December 2010 / Accepted: 20 December 2010 / Published: 20 December 2010
Cited by 45 | PDF Full-text (502 KB) | HTML Full-text | XML Full-text
Abstract
The interaction between cells and biopolymers is the evaluation indicator of the biocompatibility of materials. The purpose of this work was to examine the responses of retinal pigment epithelial (RPE) cells to genipin (GP) or glutaraldehyde (GTA) cross-linked chitosan by means of cell
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The interaction between cells and biopolymers is the evaluation indicator of the biocompatibility of materials. The purpose of this work was to examine the responses of retinal pigment epithelial (RPE) cells to genipin (GP) or glutaraldehyde (GTA) cross-linked chitosan by means of cell viability assays, cytokine expression analyses, and apoptosis assays. Evaluations of non-cross-linked chitosan were conducted simultaneously for comparison. Both GP and GTA treated samples with the same extent of cross-linking (around 80%) were prepared by varying cross-linking time. Our results showed that GP cross-linking was carried out by either radical polymerization of the monomers or SN2 nucleophilic substitution reaction involving the replacement of the ester group on the monomer with a secondary amide linkage. On the other hand, GTA could react with free amino groups of chitosan, leading to the formation of either the Schiff bases or the Michael-type adducts with terminal aldehydes. The biocompatibility of non-cross-linked chitosan membranes was demonstrated by the absence of any signs of toxicity or inflammation reaction. The present study showed that the ARPE-19 cells exposed to GTA cross-linked chitosan membranes had significantly higher cytotoxicity, interleukin-6 levels, and number of TUNEL-positive nuclei than did those exposed to GP treated samples. In addition, the materials modified with GTA trigger apoptosis at an early stage and may induce toxicity in the RPE cells later. The findings suggest that while the chitosan molecules bridged by GP are satisfactorily cytocompatible, the counterparts treated by GTA do not seem to be tolerated. In terms of material safety, the GP cross-linked chitosan may be compatible with human RPE cells and may have a potential application as delivery carriers in the treatment of posterior segment diseases. Full article
(This article belongs to the Section Materials Science)
Open AccessArticle Fe-Chlorophyllin Promotes the Growth of Wheat Roots Associated with Nitric Oxide Generation
Int. J. Mol. Sci. 2010, 11(12), 5246-5255; https://doi.org/10.3390/ijms11125246
Received: 1 November 2010 / Revised: 7 December 2010 / Accepted: 14 December 2010 / Published: 17 December 2010
Cited by 3 | PDF Full-text (499 KB) | HTML Full-text | XML Full-text
Abstract
: Effects of Fe-chlorophyllin on the growth of wheat root were investigated in this study. We found that Fe-chlorophyllin can promote root growth. The production of nitric oxide in wheat root was detected using DAF-2DA fluorescent emission. The intensity of fluorescent in the
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: Effects of Fe-chlorophyllin on the growth of wheat root were investigated in this study. We found that Fe-chlorophyllin can promote root growth. The production of nitric oxide in wheat root was detected using DAF-2DA fluorescent emission. The intensity of fluorescent in the presence of 0.1 mg/L Fe-chlorophyllin was near to that observed with the positive control of sodium nitroprusside (SNP), the nitric oxide donor. IAA oxidase activity decreased with all treatments of Fe-chlorophyllin from 0.01 to 10 mg/L. At the relatively lower Fe-chlorophyllin concentration of 0.1 mg/L, the activity of IAA oxidase displayed a remarkable decrease, being 40.1% lower than the control. Meanwhile, Fe-chlorophyllin treatment could increase the activities of reactive oxygen scavenging enzymes, such as superoxide dismutase (SOD) and peroxidase (POD), as determined using non-denaturing polyacrylamide gel electrophoresis. These results indicate that Fe-chlorophyllin contributes to the growth of wheat root associated with nitric oxide generation. Full article
(This article belongs to the Section Biochemistry, Molecular and Cellular Biology)
Open AccessArticle Differential Expression of Copper-Zinc Superoxide Dismutase Gene of Polygonum sibiricum Leaves, Stems and Underground Stems, Subjected to High-Salt Stress
Int. J. Mol. Sci. 2010, 11(12), 5234-5245; https://doi.org/10.3390/ijms11125234
Received: 30 September 2010 / Revised: 20 November 2010 / Accepted: 29 November 2010 / Published: 17 December 2010
Cited by 14 | PDF Full-text (388 KB) | HTML Full-text | XML Full-text
Abstract
In aerobic organisms, protection against oxidative damage involves the combined action of highly specialized antioxidant enzymes, such as copper-zinc superoxide dismutase. In this work, a cDNA clone which encodes a copper-zinc superoxide dismutase gene, named PS-CuZnSOD, has been identified from P.
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In aerobic organisms, protection against oxidative damage involves the combined action of highly specialized antioxidant enzymes, such as copper-zinc superoxide dismutase. In this work, a cDNA clone which encodes a copper-zinc superoxide dismutase gene, named PS-CuZnSOD, has been identified from P. sibiricum Laxm. by the rapid amplification of cDNA ends method (RACE). Analysis of the nucleotide sequence reveals that the PS-CuZnSOD gene cDNA clone consists of 669 bp, containing 87 bp in the 5' untranslated region; 459 bp in the open reading frame (ORF) encoding 152 amino acids; and 123 bp in 3' untranslated region. The gene accession nucleotide sequence number in GenBank is GQ472846. Sequence analysis indicates that the protein, like most plant superoxide dismutases (SOD), includes two conserved ecCuZnSOD signatures that are from the amino acids 43 to 51, and from the amino acids 137 to 148, and it has a signal peptide extension in the front of the N-terminus (1–16 aa). Expression analysis by real-time quantitative PCR reveals that the PS-CuZnSOD gene is expressed in leaves, stems and underground stems. PS-CuZnSOD gene expression can be induced by 3% NaHCO3. The different mRNA levels’ expression of PS-CuZnSOD show the gene’s different expression modes in leaves, stems and underground stems under the salinity-alkalinity stress. Full article
(This article belongs to the Section Biochemistry, Molecular and Cellular Biology)
Open AccessReview Deleted in Malignant Brain Tumors-1 Protein (DMBT1): A Pattern Recognition Receptor with Multiple Binding Sites
Int. J. Mol. Sci. 2010, 11(12), 5212-5233; https://doi.org/10.3390/ijms1112521
Received: 11 November 2010 / Revised: 9 December 2010 / Accepted: 9 December 2010 / Published: 17 December 2010
Cited by 31 | PDF Full-text (423 KB) | HTML Full-text | XML Full-text
Abstract
Deleted in Malignant Brain Tumors-1 protein (DMBT1), salivary agglutinin (DMBT1SAG), and lung glycoprotein-340 (DMBT1GP340) are three names for glycoproteins encoded by the same DMBT1 gene. All these proteins belong to the scavenger receptor cysteine-rich (SRCR) superfamily of proteins: a
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Deleted in Malignant Brain Tumors-1 protein (DMBT1), salivary agglutinin (DMBT1SAG), and lung glycoprotein-340 (DMBT1GP340) are three names for glycoproteins encoded by the same DMBT1 gene. All these proteins belong to the scavenger receptor cysteine-rich (SRCR) superfamily of proteins: a superfamily of secreted or membrane-bound proteins with SRCR domains that are highly conserved down to sponges, the most ancient metazoa. In addition to SRCR domains, all DMBT1s contain two CUB domains and one zona pellucida domain. The SRCR domains play a role in the function of DMBT1s, which is the binding of a broad range of pathogens including cariogenic streptococci, Helicobacter pylori and HIV. Mucosal defense proteins like IgA, surfactant proteins and lactoferrin also bind to DMBT1s through their SRCR domains. The binding motif on the SRCR domains comprises an 11-mer peptide in which a few amino acids are essential for binding (GRVEVLYRGSW). Adjacent to each individual SRCR domain are glycosylation domains, where the attached carbohydrate chains play a role in the binding of influenza A virus and Helicobacter pylori. The composition of the carbohydrate chains is not only donor specific, but also varies between different organs. These data demonstrate a role for DMBT1s as pattern recognition molecules containing various peptide and carbohydrate binding motifs. Full article
(This article belongs to the Special Issue Advances in Molecular Recognition)
Open AccessArticle Anti-Tumor Activity of a Novel Protein Obtained from Tartary Buckwheat
Int. J. Mol. Sci. 2010, 11(12), 5201-5211; https://doi.org/10.3390/ijms11125201
Received: 12 November 2010 / Revised: 18 November 2010 / Accepted: 14 December 2010 / Published: 17 December 2010
Cited by 29 | PDF Full-text (311 KB) | HTML Full-text | XML Full-text
Abstract
TBWSP31 is a novel antitumor protein that was isolated from tartary buckwheat water-soluble extracts. The objective of this paper was to investigate the anti-proliferative effects of TBWSP31 on breast cancer Bcap37cells and to explore its possible mechanism. After treatment of Bcap37 cells with
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TBWSP31 is a novel antitumor protein that was isolated from tartary buckwheat water-soluble extracts. The objective of this paper was to investigate the anti-proliferative effects of TBWSP31 on breast cancer Bcap37cells and to explore its possible mechanism. After treatment of Bcap37 cells with TBWSP31, typical apoptotic morphological changes were observed by inverted microscopy and scanning electron microscopy (SEM), such as detachment from the culture plate, change to a round shape, cell shrinkage, the absence of obvious microvilli, plasma membrane blebbing, and formation of apoptotic bodies. Cell-cycle analysis revealed that treatment with TBWSP31 resulted in a G0/G1 arrest and prevented the cells from growing from G0/G1 phase to S phase, which was most prominent at 48 h. The expression of bcl-2 and Fas were detected quantitatively by FCM, which showed that TBWSP31 induced-apoptosis may be involved with the participation of Fas and bcl-2. These results suggest that TBWSP31 is a potential antitumor compound and that apoptosis induced by TBWSP31 is a key antitumor mechanism. Full article
(This article belongs to the Section Biochemistry, Molecular and Cellular Biology)
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Open AccessReview Liquid-Liquid Phase Transition and Glass Transition in a Monoatomic Model System
Int. J. Mol. Sci. 2010, 11(12), 5184-5200; https://doi.org/10.3390/ijms11125184
Received: 16 November 2010 / Revised: 13 December 2010 / Accepted: 13 December 2010 / Published: 16 December 2010
Cited by 7 | PDF Full-text (304 KB) | HTML Full-text | XML Full-text
Abstract
We review our recent study on the polyamorphism of the liquid and glass states in a monatomic system, a two-scale spherical-symmetric Jagla model with both attractive and repulsive interactions. This potential with a parametrization for which crystallization can be avoided and both the
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We review our recent study on the polyamorphism of the liquid and glass states in a monatomic system, a two-scale spherical-symmetric Jagla model with both attractive and repulsive interactions. This potential with a parametrization for which crystallization can be avoided and both the glass transition and the liquid-liquid phase transition are clearly separated, displays water-like anomalies as well as polyamorphism in both liquid and glassy states, providing a unique opportunity to study the interplay between the liquid-liquid phase transition and the glass transition. Our study on a simple model may be useful in understanding recent studies of polyamorphism in metallic glasses. Full article
(This article belongs to the Special Issue Amorphous Alloys)
Open AccessReview Protein Microarrays and Biomarkers of Infectious Disease
Int. J. Mol. Sci. 2010, 11(12), 5165-5183; https://doi.org/10.3390/ijms11125165
Received: 19 November 2010 / Revised: 11 December 2010 / Accepted: 15 December 2010 / Published: 16 December 2010
Cited by 16 | PDF Full-text (277 KB) | HTML Full-text | XML Full-text
Abstract
Protein microarrays are powerful tools that are widely used in systems biology research. For infectious diseases, proteome microarrays assembled from proteins of pathogens will play an increasingly important role in discovery of diagnostic markers, vaccines, and therapeutics. Distinct formats of protein microarrays have
[...] Read more.
Protein microarrays are powerful tools that are widely used in systems biology research. For infectious diseases, proteome microarrays assembled from proteins of pathogens will play an increasingly important role in discovery of diagnostic markers, vaccines, and therapeutics. Distinct formats of protein microarrays have been developed for different applications, including abundance-based and function-based methods. Depending on the application, design issues should be considered, such as the need for multiplexing and label or label free detection methods. New developments, challenges, and future demands in infectious disease research will impact the application of protein microarrays for discovery and validation of biomarkers. Full article
(This article belongs to the Special Issue Biomarkers)
Open AccessReview Applications of Chitin and Its Derivatives in Biological Medicine
Int. J. Mol. Sci. 2010, 11(12), 5152-5164; https://doi.org/10.3390/ijms11125152
Received: 1 November 2010 / Revised: 2 December 2010 / Accepted: 6 December 2010 / Published: 15 December 2010
Cited by 112 | PDF Full-text (215 KB) | HTML Full-text | XML Full-text
Abstract
Chitin and its derivatives—as a potential resource as well as multiple functional substrates—have generated attractive interest in various fields such as biomedical, pharmaceutical, food and environmental industries, since the first isolation of chitin in 1811. Moreover, chitosan and its chitooligosaccharides (COS) are degraded
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Chitin and its derivatives—as a potential resource as well as multiple functional substrates—have generated attractive interest in various fields such as biomedical, pharmaceutical, food and environmental industries, since the first isolation of chitin in 1811. Moreover, chitosan and its chitooligosaccharides (COS) are degraded products of chitin through enzymatic and acidic hydrolysis processes; and COS, in particular, is well suited for potential biological application, due to the biocompatibility and nontoxic nature of chitosan. In this review, we investigate the current bioactivities of chitin derivatives, which are all correlated with their biomedical properties. Several new and cutting edge insights here may provide a molecular basis for the mechanism of chitin, and hence may aid its use for medical and pharmaceutical applications. Full article
(This article belongs to the Section Materials Science)
Open AccessArticle Constitutive Expression of Thermobifida fusca Thermostable Acetylxylan Esterase Gene in Pichia pastoris
Int. J. Mol. Sci. 2010, 11(12), 5143-5151; https://doi.org/10.3390/ijms11125143
Received: 17 November 2010 / Revised: 1 December 2010 / Accepted: 9 December 2010 / Published: 15 December 2010
Cited by 9 | PDF Full-text (112 KB) | HTML Full-text | XML Full-text
Abstract
A gene encoding the thermostable acetylxylan esterase (AXE) in Thermobifida fusca NTU22 was amplified by PCR, sequenced and cloned into the Pichia pastoris X-33 host strain using the vector pGAPZαA, allowing constitutive expression and secretion of the protein. Recombinant expression resulted in high
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A gene encoding the thermostable acetylxylan esterase (AXE) in Thermobifida fusca NTU22 was amplified by PCR, sequenced and cloned into the Pichia pastoris X-33 host strain using the vector pGAPZαA, allowing constitutive expression and secretion of the protein. Recombinant expression resulted in high levels of extracellular AXE production, as high as 526 U/mL in the Hinton flask culture broth. The purified enzyme showed a single band at about 28 kDa by SDS-polyacrylamide gel electrophoresis after being treated with endo-β-N-acetylglycosaminidase H; this agrees with the predicted size based on the nucleotide sequence. About 70% of the original activity remained after heat treatment at 60 °C for three hours. The optimal pH and temperature of the purified enzyme were 8.0 and 60 °C, respectively. The properties of the purified AXE from the P. pastoris transformant are similar to those of the AXE from an E. coli transformant. Full article
(This article belongs to the Section Biochemistry, Molecular and Cellular Biology)
Open AccessArticle Molecular Interactions and Protein-Induced DNA Hairpin in the Transcriptional Control of Bacteriophage Ø29 DNA
Int. J. Mol. Sci. 2010, 11(12), 5129-5142; https://doi.org/10.3390/ijms11125129
Received: 8 October 2010 / Revised: 22 November 2010 / Accepted: 7 December 2010 / Published: 13 December 2010
Cited by 1 | PDF Full-text (507 KB) | HTML Full-text | XML Full-text
Abstract
Studies on the regulation of phage Ø29 gene expression revealed a new mechanism to accomplish simultaneous activation and repression of transcription leading to orderly gene expression. Two phage-encoded early proteins, p4 and p6, bind synergistically to DNA, modifying the topology of the sequences
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Studies on the regulation of phage Ø29 gene expression revealed a new mechanism to accomplish simultaneous activation and repression of transcription leading to orderly gene expression. Two phage-encoded early proteins, p4 and p6, bind synergistically to DNA, modifying the topology of the sequences encompassing early promoters A2c and A2b and late promoter A3 in a hairpin that allows the switch from early to late transcription. Protein p6 is a nucleoid-like protein that binds DNA in a non-sequence specific manner. Protein p4 is a sequence-specific DNA binding protein with multifaceted sequence-readout properties. The protein recognizes the chemical signature of only one DNA base on the inverted repeat of its target sequence through a direct-readout mechanism. In addition, p4 specific binding depends on the recognition of three A-tracts by indirect-readout mechanisms. The biological importance of those three A-tracts resides in their individual properties rather than in the global curvature that they may induce. Full article
(This article belongs to the Special Issue Advances in Molecular Recognition)
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