bluuebunny/crossref_metadata_2025_split huggingface dataset:
Differential recognition of syk‐binding sites by each of the two phosphotyrosine‐binding pockets of the Vav SH2 domain
Authors: Chen Chih‐Hong , Piraner Dan , Gorenstein Nina M. , Geahlen Robert L. , Beth Post Carol 
Published: August 2013

ABSTRACTThe association of spleen tyrosine kinase (Syk), a central tyrosine kinase in B cell signaling, with Vav SH2 domain is controlled by phosphorylation of two closely spaced tyrosines in Syk linker B: Y342 and Y346. Previous studies established both singly phosphorylated and doubly phosphorylated forms play a role in signaling. The structure of the doubly phosphorylated form identified a new recognition of phosphotyrosine whereby two phosphotyrosines bind simultaneously to the Vav SH2 domain, one in the canonical pTyr pocket and one in the specificity pocket on the opposite side of the central β‐sheet. It is unknown if the specificity pocket can bind phosphotyrosine independent of phosphotyrosine binding the pTyr pocket. To address this gap in knowledge, we determined the structure of the complex between Vav1 SH2 and a peptide (SykLB‐YpY) modeling the singly phosphorylated‐Y346 form of Syk with unphosphorylated Y342. The nuclear magnetic resonance (NMR) data conclusively establish that recognition of phosphotyrosine is swapped between the two pockets; phosphorylated pY346 binds the specificity pocket of Vav1 SH2, and unphosphorylated Y342 occupies what is normally the pTyr binding pocket. Nearly identical changes in chemical shifts occurred upon binding all three forms of singly and doubly phosphorylated peptides; however, somewhat smaller shift perturbations for SykLB‐YpY from residues in regions of high internal mobility suggest that internal motions are coupled to binding affinity. The differential recognition that includes this swapped binding of phosphotyrosine to the specificity pocket of Vav SH2 increases the repertoire of possible phosphotyrosine binding by SH2 domains in regulating protein‐protein interactions in cellular signaling. © 2013 Wiley Periodicals, Inc. Biopolymers 99: 897–907, 2013.
Particle tracking microrheology of purified gastrointestinal mucins
Authors: Georgiades Pantelis , Pudney Paul D. A. , Thornton David J. , Waigh Thomas A. 
Published: August 2013

AbstractThe rheological characteristics of gastric and duodenal mucin solutions, the building blocks of the mucus layer that covers the epithelia of the two organs, were investigated using particle tracking microrheology. We used biochemically well characterized purified porcine mucins (MUC5AC and MUC2) as models for human mucins, to probe their viscoelasticity as a function of mucin concentration and pH. Furthermore, we used both reducing (dithiothreitol, DTT) and chaotropic agents (guanidinium chloride and urea) to probe the mesoscopic forces that mediate the integrity of the polymer network. At neutral pH both gastric and duodenal mucins formed self‐assembled semi‐dilute networks above a certain critical mucin concentration (c*) with the viscosity (η) scaling as
for MUC5AC and
for MUC2, where c is the mucin concentration. Above an even higher mucin concentration threshold (ce, the entanglement concentration) reptation occurs and there is a dramatic increase in the viscosity scaling,
for MUC5AC and
for MUC2. The dynamics of the self‐assembled comb polymers is examined in terms of a scaling model for flexible polyelectrolyte combs. Both duodenum and gastric mucin are found to be pH switchable gels, gelation occurring at low pHs. There is a hundred‐fold increase in the elastic shear modulus once the pH is decreased. The addition of DTT, guanidinium chloride and urea disassembles both the semi‐dilute and gel structures causing a large increase in the compliance (decrease in their shear moduli). Addition of the polyphenol EGCG has a reverse effect on mucin viscoelasticity, that is, it triggers a sol–gel transition in semi‐dilute mucin solutions at neutral pH. © 2013 The Authors. Biopolymers published by Wiley Periodicals, Inc. Biopolymers 101: 366–377, 2014.
Characterization and assembly of a GFP‐tagged cylindriform silk into hexameric complexes
Authors: Öster Carl , Bonde Johan Svensson , Bülow Leif , Dicko Cedric 
Published: August 2013

ABSTRACTSpider silk has been studied extensively for its attractive mechanical properties and potential applications in medicine and industry. The production of spider silk, however, has been lagging behind for lack of suitable systems. Our approach focuses on solving the production of spider silk by designing, expressing, purifying and characterizing the silk from cylindriform glands. We show that the cylindriform silk protein, in contrast to the commonly used dragline silk protein, is fully folded and stable in solution. With the help of GFP as a fusion tag we enhanced the expression of the silk protein in Escherichia coli and could optimize the downstream processing. Secondary structures analysis by circular dichroism and FTIR shows that the GFP‐silk fusion protein is predominantly α‐helical, and that pH can trigger a α‐ to β‐transition resulting in aggregation. Structural analysis by small angle X‐ray scattering suggests that the GFP‐Silk exists in the form of a hexamer in solution. © 2013 Wiley Periodicals, Inc. Biopolymers 101: 378–390, 2014.
A high‐throughput screen for antibiotic drug discovery
Authors: Scanlon Thomas C. , Dostal Sarah M. , Griswold Karl E. 
Published: August 2013

ABSTRACTWe describe an ultra‐high‐throughput screening platform enabling discovery and/or engineering of natural product antibiotics. The methodology involves creation of hydrogel‐in‐oil emulsions in which recombinant microorganisms are co‐emulsified with bacterial pathogens; antibiotic activity is assayed by use of a fluorescent viability dye. We have successfully utilized both bulk emulsification and microfluidic technology for the generation of hydrogel microdroplets that are size‐compatible with conventional flow cytometry. Hydrogel droplets are ∼25 pL in volume, and can be synthesized and sorted at rates exceeding 3,000 drops/s. Using this technique, we have achieved screening throughputs exceeding 5 million clones/day. Proof‐of‐concept experiments demonstrate efficient selection of antibiotic‐secreting yeast from a vast excess of negative controls. In addition, we have successfully used this technique to screen a metagenomic library for secreted antibiotics that kill the human pathogen Staphylococcus aureus. Our results establish the practical utility of the screening platform, and we anticipate that the accessible nature of our methods will enable others seeking to identify and engineer the next generation of antibacterial biomolecules. Biotechnol. Bioeng. 2014;111: 232–243. © 2013 Wiley Periodicals, Inc.
Vitrification of immaturemouse oocytes by the modified‐cut standard straw method
Authors: Jang Woo‐In , Lee Seung‐Eun , Choi Hyun‐Yong , Lim Joon‐Gyo , Heo Young‐Tae , Cui Xiang‐Shun , Kim Nam‐Hyung 
Published: August 2013

AbstractThe feasibility of using the modified‐cut standard straw (M‐CSS) method for the vitrification of immature mouse oocytes has been tested. The effects of different vitrification methods on oocyte survival, cytoskeletal organization, the distribution of cortical granules (CGs), and apoptosis have also been compared. Immature mouse oocytes were vitrified–thawed using electron microscope grid or M‐CSS method, and cultured to meiosis II (MII) stage. Oocyte development, cytoskeletal organization, CG distribution, and the expression of apoptosis‐related genes were evaluated. Rates of recovery (91.7 vs. 74.9%) and survival (89.0 vs. 62.6%) were significantly higher in M‐CSS group than in EM grid group. The number of oocytes with normal chromosome alignment at the spindle and spindle morphology were similar in both groups. However, the actin cap was significantly degraded in EM grid groups (52.6 vs. 35.1%, respectively). Abnormal release of CGs also frequently occurred in EM grid groups (42.6 vs. 32.7%, respectively). Pro‐apoptosis‐related gene expression levels of Bax, caspase 3 were expressed lower than control in MII stage oocytes derived from M‐CSS group; anti apoptosis‐related genes, survivin and heat shock factor‐1 (Hsf‐1) were slightly increased. However, all genes expression was significantly increased in MII stage oocytes derived from EM grid groups. Vitrification reduces the survival rate of immature mouse oocytes, alters cytoskeletal organization and CG distribution, and promotes apoptosis. However, these effects are less pronounced in vitrified oocytes generated by M‐CSS than in those generated by EM grid method. Therefore, the novel M‐CSS is a feasible approach for the cryopreservation of immature mouse oocytes.
Overexpression of vasostatin‐1 protects hypoxia/reoxygenation injuries in cardiomyocytes–endothelial cells transwell co‐culture system
Authors: Liu Jian , Yang Dicheng , Shi Sheng , Lin Lei , Xiao Mingdi , Yuan Zhongxiang , Yu Min 
Published: August 2013

AbstractVasostatin‐1 (VS‐1) plays important roles in myocardial ischemia/reperfusion injury. We have explored the protective effects of VS‐1 on cardiomyocytes using cardiomyocyte–endothelial cells Transwell Co‐culture System. Cardiomyocytes and rat aortic endothelial cells (RAECs) were prepared from ventricles and thoraco‐abdominal aorta of Sprague–Dawley rats. The experiment used cardiomyocytes alone culture group (C) and cardiomyocytes‐RAECs co‐culture group (T), each with three subgroups: C‐Ad‐Null, C‐Ad‐VS‐1, C‐Hb (Ad‐VS‐1 + NO scavenger Hb), or T‐Ad‐Null, T‐Ad‐VS‐1 transfection, T‐Hb. After 48 h incubation, all groups were treated with hypoxia for 60 min and then reoxygenated for 120 min. We also investigated endothelial cells‐mediated cardiomyocytes protection. RAECs were treated with hypoxia for 30 min and reoxygenated with normal cardiomyocytes for 120 min. The cardiomyocytes apoptosis rate, aspartate aminotransferase (AST) and creatine kinase isozyme MB (CK‐MB) were recorded. As expected, cardiomyocytes apoptosis, AST and CK‐MB were significantly increased in the T‐Ad‐Null group than in the C‐Ad‐Null group. VS transfection significantly reduced these levels. However, apoptosis, AST and CK‐MB levels were increased again after Hb treatment, returning to the similar level of the C‐Ad‐null group in the C‐Hb group, but still significantly lower in the T‐Hb group compared with the T‐Ad‐null group. RAEC injury caused cardiomyocyte injury, and VS‐1 transfection of the RAEC decreased apoptosis and the levels of AST and CK‐MB. The findings suggest that VS‐1 exerts protective effects on the cardiomyocytes directly or indirectly by cardiomyocyte–endothelial cells interaction.
Folate decorated magnetite nanoparticles: Synthesis and targeted therapy against ovarian cancer
Authors: Fazilati Mohammad 
Published: August 2013

AbstractDoxorubicin (DOX) loaded folate‐coated magnetic Fe3O4 nanoparticles (MNPs) were prepared by co‐precipitation and emulsification cross‐linking method and uniform NPs with an average particle size of 15 (bare) and 35 nm (FA‐MNPs), with high encapsulation efficiencies (EE), were obtained. The release profiles of conjugated DOX showed that pH 6.0 provided suitable conditions for proper drug release. IC50 analysis of C30 and CP70 cell lines after 96 h (4 days) exposure to DOX‐FA‐MNPs showed that the most significant IC50 were at 5.4 ± 0.6 and 11.2 ± 2.7 mM DOX loaded onto the FA‐MNPs. Thus CP70 cells are more resistant to lower concentrations of drug compared to C30 cells (P < 0.05). C30 and CP70 cells reached 91 and 81.8% apoptosis after administration of DOX‐FA‐MNPs (5 mg/mL) compared to 49.2 and 46.6% after administration of the free drug, respectively (P < 0.05). this study indicates that FA modified MNPs enhances the DOX‐induced apoptosis in both of the human ovarian cancer cell lines with sharp decreases in the levels of bcl‐2 and surviving, and increased expression of caspase‐3.
Effects of PTHrP on expression of MMP9 and MMP13 in sika deer antler chondrocytes
Authors: Wang Shou‐Tang , Gao Ying‐Jie , Duan Cui‐Cui , Li Dang‐Dang , Tian Xue‐Chao , Zhang Qiao‐Ling , Guo Bin , Yue Zhan‐Peng 
Published: August 2013

AbstractDeer antlers are the only mammalian appendages to display an annual cycle of full regeneration. However, little is known about the molecular mechanisms of antler regeneration. Our previous study has demonstrated that parathyroid hormone‐related peptide (PTHrP) can promote proliferation of antler chondrocytes and inhibit its differentiation, but the mechanism underlying such regulation is not fully understood. We have determined the role of PTHrP on the mRNA expression of matrix metalloproteinase‐9 (MMP9) and MMP13 in the antler chondrocytes. The possible pathways that transduce PTHrP effects were examined. In situ hybridization showed that MMP9 and MMP13 were mainly localized in the dermal fibroblasts, perichondrium, and cartilage in the sika deer antler, of which MMP9 and MMP13 were highly expressed in the chondrocytes. Exogenous PTHrP could inhibit the expression of MMP9 and MMP13 in the antler chondrocytes. The inhibitory effect of PTHrP on MMP9 was abolished by JNK inhibitor, SP600125, while P38MAPK inhibitor SB203850 and PKC inhibitor GF109203X could rescue the inhibitory effect of PTHrP on MMP13. The results suggest that PTHrP can inhibit MMP9 expression by JNK signaling pathway and MMP13 expression by p38MAPK and PKC signaling pathways in the antler chondrocytes. Thus PTHrP is involved in the control of antler chondrocytes maturation and cartilage matrix degradation.
PEITC reverse multi‐drug resistance of human gastric cancer SGC7901/DDP cell line
Authors: Tang Tao , Song Xin , Liu Yu‐Fen , Wang Wen‐Yue 
Published: August 2013

AbstractGastric cancer is one of the leading causes of cancer death in the world and nearly all patients who respond initially to cisplatin later develop drug resistance, indicating multi‐drug resistance is an essential aspect of the failure of treatment. Phenethyl isothiocyanate (PEITC) has been implicated in inhibiting metastasis of several types of human cancer. However, the effect and potential mechanism of PEITC reversed multi‐drug resistance of human gastric cancer is not fully clear. We have identified the role of PEITC in multi‐drug resistance reversal of human gastric cancer SGC7901/DDP cell line. PEITC inhibited cisplatin‐resistant human SGC7901/DDP cell growth in a dose‐dependent manner, causing increased apoptosis, ROS generation, glutathione depletion, accumulation of Rhodamine‐123, decreased expression of P‐glycoprotein and cell cycle arrest. mRNA and protein expression of the multi‐drug resistance gene (MDR1), multi‐drug resistance‐associated protein (MRP1), excision repair cross‐complementing gene 1 (ERCC1), survivin, and Mad2 was decreased, and phosphorylation of Akt and transcriptional activation of NF‐κB were suppressed. PEITC may be useful as the therapeutic strategy for overcoming multi‐drug resistance through suppressing the PI3K‐Akt pathway in human gastric cancer.
Hypoxia induces adipocyte differentiation of adipose‐derived stem cells by triggering reactive oxygen species generation
Authors: Kim Ji Hye , Kim Seok‐Ho , Song Seung Yong , Kim Won‐Serk , Song Sun U. , Yi TacGhee , Jeon Myung‐Shin , Chung Hyung‐Min , Xia Ying , Sung Jong‐Hyuk 
Published: August 2013

AbstractGeneration of reactive oxygen species (ROS) by NADPH oxidase 4 (Nox4) induces the proliferation and migration of adipose‐derived stem cells (ASCs). However, the functional role of mitochondrial ROS (mtROS) generation in ASCs is unknown. Therefore, we have investigated whether hypoxia induces the differentiation of ASCs via ROS generation. We also have tried to identify the cellular mechanisms of ROS generation underlying adipocyte differentiation. Hypoxia (2%) and ROS generators, such as antimycin and rotenone, induced adipocyte differentiation, which was attenuated by an ROS scavenger. Although Nox4 generates ROS and regulates proliferation of ASCs, Nox4 inhibition or Nox4 silencing did not inhibit adipocyte differentiation; indeed fluorescence intensity of mito‐SOX increased in hypoxia, and treatment with mito‐CP, a mtROS scavenger, significantly reduced hypoxia‐induced adipocyte differentiation. Phosphorylation of Akt and mTOR was induced by hypoxia, while inhibition of these molecules prevented adipocyte differentiation. Thus hypoxia induces adipocyte differentiation by mtROS generation, and the PI3K/Akt/mTOR pathway is involved.
Clinical significance of circulating tumor cells in peripheral blood from patients with gastric cancer
Authors: Uenosono Yoshikazu , Arigami Takaaki , Kozono Tsutomu , Yanagita Shigehiro , Hagihara Takahiko , Haraguchi Naoto , Matsushita Daisuke , Hirata Munetsugu , Arima Hideo , Funasako Yawara , Kijima Yuko , Nakajo Akihiro , Okumura Hiroshi , Ishigami Sumiya , Hokita Shuichi , Ueno Shinichi , Natsugoe Shoji 
Published: August 2013

BACKGROUNDThe authors hypothesized that circulating tumor cells (CTCs) in patients with gastric cancer are associated with prognosis and disease recurrence. In this study, they evaluated CTCs in gastric cancer and clarified the clinical impact of CTCs.METHODSIn total, 265 consecutive patients with gastric cancer were enrolled. Fourteen patients were excluded from the analysis, including 12 patients who another cancer and 2 patients who refused the treatment. The remaining 251 patients were divided into 2 groups: 148 patients who underwent gastrectomy (the resection group) and 103 patients who did not undergo gastrectomy (the nonresectable group). Peripheral blood samples were collected before gastrectomy or chemotherapy. A proprietary test for capturing, identifying, and counting CTCs in blood was used for the isolation and enumeration of CTCs.RESULTSCTCs were detected in 16 patients (10.8%) from the resection group and in 62 patients (60.2%) from the nonresectable group. The overall survival rate for the entire cohort was significantly lower in patients with CTCs than in those without CTCs (P < .0001). In the resection group, relapse‐free and overall survival in patients with CTCs was significantly lower than in patients without CTCs (P < .0001). It was noteworthy that the expression of CTCs was an independent factor for determining the overall survival of patients with gastric cancer in multivariate analysis (P = .024). In the nonresectable group, the overall survival rate was significantly lower in patients with CTCs than in those without CTCs (P = .0044).CONCLUSIONSThe evaluation of CTCs in peripheral blood may be a useful tool for predicting tumor progression, prognosis, and the effect of chemotherapy in patients with gastric cancer. Cancer 2013;119:3984–3991. © 2013 American Cancer Society.
Local Li Coordination and Ionic Transport in Methacrylate‐Based Gel Polymer Electrolytes
Authors: Voigt Nadine , Isken Philipp , Lex‐Balducci Alexandra , van Wüllen Leo 
Published: August 2013

AbstractThe local Li cation coordination motifs and the interactions between the hosting methacrylate‐based polymer membrane and the liquid electrolyte [1 M LiPF6 in ethylene carbonate (EC)/dimethyl carbonate (DMC)] are studied by employing liquid and solid‐state NMR spectroscopy. At low temperatures, two different coordination modes for Li cations are identified with the help of dipolar‐based solid‐state NMR techniques, one of which is the exclusive coordination by DMC molecules, while the other is a co‐coordination by the polymer and DMC molecules. At room temperature, Li cations are found to be extremely mobile, coordinated by EC and DMC molecules as well as the copolymer, as found by liquid‐state NMR spectroscopy.
On the origins of human handedness and language: A comparative review of hand preferences for bimanual coordinated actions and gestural communication in nonhuman primates
Authors: Meguerditchian Adrien , Vauclair Jacques , Hopkins William D. 
Published: August 2013

ABSTRACTWithin the evolutionary framework about the origin of human handedness and hemispheric specialization for language, the question of expression of population‐level manual biases in nonhuman primates and their potential continuities with humans remains controversial. Nevertheless, there is a growing body of evidence showing consistent population‐level handedness particularly for complex manual behaviors in both monkeys and apes. In the present article, within a large comparative approach among primates, we will review our contribution to the field and the handedness literature related to two particular sophisticated manual behaviors regarding their potential and specific implications for the origins of hemispheric specialization in humans: bimanual coordinated actions and gestural communication. Whereas bimanual coordinated actions seem to elicit predominance of left‐handedness in arboreal primates and of right‐handedness in terrestrial primates, all handedness studies that have investigated gestural communication in several primate species have reported stronger degree of population‐level right‐handedness compared to noncommunicative actions. Communicative gestures and bimanual actions seem to affect differently manual asymmetries in both human and nonhuman primates and to be related to different lateralized brain substrates. We will discuss (1) how the data of hand preferences for bimanual coordinated actions highlight the role of ecological factors in the evolution of handedness and provide additional support the postural origin theory of handedness proposed by MacNeilage [MacNeilage [2007]. Present status of the postural origins theory. In W. D. Hopkins (Ed.), The evolution of hemispheric specialization in primates (pp. 59–91). London: Elsevier/Academic Press] and (2) the hypothesis that the emergence of gestural communication might have affected lateralization in our ancestor and may constitute the precursors of the hemispheric specialization for language. © 2013 Wiley Periodicals, Inc. Dev Psychobiol 55: 637–650, 2013.
Synthesis of ortho‐Hydroxybenzophenones Catalyzed by Magnetically Retrievable Fe3O4 Nanoparticles under Ligand‐Free Conditions
Authors: Ramani Thekkathu , Umadevi Paspulati , Prasanth K. Leon , Sreedhar Bojja 
Published: August 2013

Abstractortho‐Benzoylation of phenols with aryl aldehydes to afford the substituted 2‐hydroxybenzophenones can be catalyzed efficiently by Fe3O4 nanoparticles under ligand‐free conditions. This method is useful for the preparation of xanthones in good yields. The catalyst can be magnetically removed and recycled easily over four cycles without a significant decrease in activity.
Indigo Carmine as New Label in PNA Biosensor for Detection of Short Sequence of p53 Tumor Suppressor Gene
Authors: Hamidi‐Asl Ezat , Raoof Jahan Bakhsh , Ojani Reza , Hejazi Mohammad Saeid 
Published: August 2013

AbstractA new electrochemical PNA hybridization biosensor for detection of a 15‐mer sequence unique to p53 using indigo carmine (IC) as an electrochemical detector is described in this work. This genosensor is based on the hybridization of target oligonucleotide with its complementary probe immobilized on the gold electrode by self‐assembled monolayer formation. Because this label is electroactive in acidic medium, the interaction between IC and short sequence of p53 is studied by differential pulse voltammety (DPV) in 0.1 M H2SO4. The results of electrochemical impedance spectroscopy and cyclic voltammetry in the solution of [Fe(CN)6]3−/4− shows no breakage in PNA‐DNA duplex. A decrease in the voltammetric peak currents of IC is observed upon hybridization of the probe with the target DNA. The influence of probe concentration on effective discrimination against non‐complementary oligonucleotides is investigated and a concentration of 10−7 M is selected. The diagnostic performance of the PNA sensor is described and the detection limit is found to be 4.31×10−12 M.