bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mass spectrometry imaging reveals new biological roles for choline esters and Tyrian purple precursors in muricid molluscs
Authors: Rudd David , Ronci Maurizio , Johnston Martin R. , Guinan Taryn , Voelcker Nicolas H. , Benkendorff Kirsten 
Published: September 2015

AbstractDespite significant advances in chemical ecology, the biodistribution, temporal changes and ecological function of most marine secondary metabolites remain unknown. One such example is the association between choline esters and Tyrian purple precursors in muricid molluscs. Mass spectrometry imaging (MSI) on nano-structured surfaces has emerged as a sophisticated platform for spatial analysis of low molecular mass metabolites in heterogeneous tissues, ideal for low abundant secondary metabolites. Here we applied desorption-ionisation on porous silicon (DIOS) to examinein situchanges in biodistribution over the reproductive cycle. DIOS-MSI showed muscle-relaxing choline ester murexine to co-localise with tyrindoxyl sulfate in the biosynthetic hypobranchial glands. But during egg-laying, murexine was transferred to the capsule gland and then to the egg capsules, where chemical ripening resulted in Tyrian purple formation. Murexine was found to tranquilise the larvae and may relax the reproductive tract. This study shows that DIOS-MSI is a powerful tool that can provide new insights into marine chemo-ecology.
Enhancing flavonoid production by systematically tuning the central metabolic pathways based on a CRISPR interference system in Escherichia coli
Authors: Wu Junjun , Du Guocheng , Chen Jian , Zhou Jingwen 
Published: September 2015

AbstractThe limited supply of intracellular malonyl-CoA in Escherichia coli impedes the biological synthesis of polyketides, flavonoids and biofuels. Here, a clustered regularly interspaced short palindromic repeats (CRISPR) interference system was constructed for fine-tuning central metabolic pathways to efficiently channel carbon flux toward malonyl-CoA. Using synthetic sgRNA to silence candidate genes, genes that could increase the intracellular malonyl-CoA level by over 223% were used as target genes. The efficiencies of repression of these genes were tuned to achieve appropriate levels so that the intracellular malonyl-CoA level was enhanced without significantly altering final biomass accumulation (the final OD600 decreased by less than 10%). Based on the results, multiple gene repressing was successful in approaching the limit of the amount of malonyl-CoA needed to produce the plant-specific secondary metabolite (2S)-naringenin. By coupling the genetic modifications to cell growth, the combined effects of these genetic perturbations increased the final (2S)-naringenin titer to 421.6 mg/L, which was 7.4-fold higher than the control strain. The strategy described here could be used to characterize genes that are essential for cell growth and to develop E. coli as a well-organized cell factory for producing other important products that require malonyl-CoA as a precursor.
A new formulation of Gamma Delta Tocotrienol has superior bioavailability compared to existing Tocotrienol-Rich Fraction in healthy human subjects
Authors: Meganathan Puvaneswari , Jabir Rafid Salim , Fuang Ho Gwo , Bhoo-Pathy Nirmala , Choudhury Roma Basu , Taib Nur Aishah , Nesaretnam Kalanithi , Chik Zamri 
Published: September 2015

AbstractGamma and delta tocotrienols are isomers of Vitamin E with established potency in pre-clinical anti-cancer research. This single-dose, randomized, crossover study aimed to compare the safety and bioavailability of a new formulation of Gamma Delta Tocotrienol (GDT) in comparison with the existing Tocotrienol-rich Fraction (TRF) in terms of gamma and delta isomers in healthy volunteers. Subjects were given either two 300 mg GDT (450 mg γ-T3 and 150 mg δ-T3) capsules or four 200 mg TRF (451.2 mg γ-T3 & 102.72 mg δ-T3) capsules and blood samples were taken at several time points over 24 hours. Plasma tocotrienol concentrations were determined using HPLC method. The 90% CI for gamma and delta tocotrienols for the ratio of log-transformation of GDT/TRF for Cmax and AUC0–∞ (values were anti-logged and expressed as a percentage) were beyond the bioequivalence limits (106.21–195.46, 154.11–195.93 and 52.35–99.66, 74.82–89.44 respectively). The Wilcoxon Signed Rank Test for Tmax did not show any significant difference between GDT and TRF for both isomers (p > 0.05). No adverse events were reported during the entire period of study. GDT was found not bioequivalent to TRF, in terms of AUC and Cmax. Gamma tocotrienol in GDT showed superior bioavailability whilst delta tocotrienol showed less bioavailability compared to TRF.
Thermosensitive hydrogel containing dexamethasone micelles for preventing postsurgical adhesion in a repeated-injury model
Authors: Wu Qinjie , Wang Ning , He Tao , Shang Jinfeng , Li Ling , Song Linjiang , Yang Xi , Li Xia , Luo Na , Zhang Wenli , Gong Changyang 
Published: September 2015

AbstractTissue adhesion is a common complication after surgery. In this work, a dexamethasone loaded polymeric micelles in thermosensitive hydrogel composite (Dex hydrogel) was prepared, which combined the anti-adhesion barrier with controlled release of anti-adhesion drug. Dexamethasone (Dex) was encapsulated in polymeric micelles (Dex micelles) and then the Dex micelles were loaded into biodegradable and thermosensitive hydrogel. The obtained Dex hydrogel showed a temperature-dependent sol-gel-sol phase transition behavior. The Dex hydrogel could form a non-flowing gel in situ upon subcutaneous injection and gradually degrade in about 20 days. In addition, Dex hydrogel was assigned for anti-adhesion studies in a more rigorous recurrent adhesion animal model. Compared with normal saline (NS) and Dex micelles group, tissue adhesions in hydrogel and Dex hydrogel group were significantly alleviated. In Dex hydrogel group, the media adhesion score is 0, which was dramatically lower than that in blank hydrogel group (2.50, P < 0.001). In histopathological examination and scanning electron microscopy (SEM) analysis, an integral neo-mesothelial cell layer with microvilli on their surface was observed, which revealed that the injured parietal and visceral peritoneum were fully recovered without the concerns of adhesion formation. Our results suggested that Dex hydrogel may serve as a potential anti-adhesion candidate.
Physicochemical and biological characterization of chitosan-microRNA nanocomplexes for gene delivery to MCF-7 breast cancer cells
Authors: Santos-Carballal B. , Aaldering L. J. , Ritzefeld M. , Pereira S. , Sewald N. , Moerschbacher B. M. , Götte M. , Goycoolea F. M. 
Published: September 2015

AbstractCancer gene therapy requires the design of non-viral vectors that carry genetic material and selectively deliver it with minimal toxicity. Non-viral vectors based on cationic natural polymers can form electrostatic complexes with negatively-charged polynucleotides such as microRNAs (miRNAs). Here we investigated the physicochemical/biophysical properties of chitosan–hsa-miRNA-145 (CS–miRNA) nanocomplexes and the biological responses of MCF-7 breast cancer cells cultured in vitro. Self-assembled CS–miRNA nanocomplexes were produced with a range of (+/−) charge ratios (from 0.6 to 8) using chitosans with various degrees of acetylation and molecular weight. The Z-average particle diameter of the complexes was <200 nm. The surface charge increased with increasing amount of chitosan. We observed that chitosan induces the base-stacking of miRNA in a concentration dependent manner. Surface plasmon resonance spectroscopy shows that complexes formed by low degree of acetylation chitosans are highly stable, regardless of the molecular weight. We found no evidence that these complexes were cytotoxic towards MCF-7 cells. Furthermore, CS–miRNA nanocomplexes with degree of acetylation 12% and 29% were biologically active, showing successful downregulation of target mRNA expression in MCF-7 cells. Our data, therefore, shows that CS–miRNA complexes offer a promising non-viral platform for breast cancer gene therapy.
Octanoylation of early intermediates of mycobacterial methylglucose lipopolysaccharides
Authors: Maranha Ana , Moynihan Patrick J. , Miranda Vanessa , Correia Lourenço Eva , Nunes-Costa Daniela , Fraga Joana S. , José Barbosa Pereira Pedro , Macedo-Ribeiro Sandra , Ventura M. Rita , Clarke Anthony J. , Empadinhas Nuno 
Published: September 2015

AbstractMycobacteria synthesize unique intracellular methylglucose lipopolysaccharides (MGLP) proposed to modulate fatty acid metabolism. In addition to the partial esterification of glucose or methylglucose units with short-chain fatty acids, octanoate was invariably detected on the MGLP reducing end. We have identified a novel sugar octanoyltransferase (OctT) that efficiently transfers octanoate to glucosylglycerate (GG) and diglucosylglycerate (DGG), the earliest intermediates in MGLP biosynthesis. Enzymatic studies, synthetic chemistry, NMR spectroscopy and mass spectrometry approaches suggest that, in contrast to the prevailing consensus, octanoate is not esterified to the primary hydroxyl group of glycerate but instead to the C6 OH of the second glucose in DGG. These observations raise important new questions about the MGLP reducing end architecture and about subsequent biosynthetic steps. Functional characterization of this unique octanoyltransferase, whose gene has been proposed to be essential forM. tuberculosisgrowth, adds new insights into a vital mycobacterial pathway, which may inspire new drug discovery strategies.
Remote control of magnetostriction-based nanocontacts at room temperature
Authors: Jammalamadaka S. Narayana , Kuntz Sebastian , Berg Oliver , Kittler Wolfram , Kannan U. Mohanan , Chelvane J. Arout , Sürgers Christoph 
Published: September 2015

AbstractThe remote control of the electrical conductance through nanosized junctions at room temperature will play an important role in future nano-electromechanical systems and electronic devices. This can be achieved by exploiting the magnetostriction effects of ferromagnetic materials. Here we report on the electrical conductance of magnetic nanocontacts obtained from wires of the giant magnetostrictive compound Tb0.3Dy0.7Fe1.95 as an active element in a mechanically controlled break-junction device. The nanocontacts are reproducibly switched at room temperature between “open” (zero conductance) and “closed” (nonzero conductance) states by variation of a magnetic field applied perpendicularly to the long wire axis. Conductance measurements in a magnetic field oriented parallel to the long wire axis exhibit a different behaviour where the conductance switches between both states only in a limited field range close to the coercive field. Investigating the conductance in the regime of electron tunneling by mechanical or magnetostrictive control of the electrode separation enables an estimation of the magnetostriction. The present results pave the way to utilize the material in devices based on nano-electromechanical systems operating at room temperature.
PrP charge structure encodes interdomain interactions
Authors: Martínez Javier , Sánchez Rosa , Castellanos Milagros , Makarava Natallia , Aguzzi Adriano , Baskakov Ilia V. , Gasset María 
Published: September 2015

AbstractAlmost all proteins contain charged residues and their chain distribution is tailored to fulfill essential ionic interactions for folding, binding and catalysis. Among proteins, the hinged two-domain chain of the cellular prion protein (PrPC) exhibits a peculiar charge structure with unclear consequences in its structural malleability. To decipher the charge design role, we generated charge-reverted mutants for each domain and analyzed their effect on conformational and metabolic features. We found that charges contain the information for interdomain interactions. Use of dynamic light scattering and thermal denaturation experiments delineates the compaction of the α-fold by an electrostatic compensation between the polybasic 23–30 region and the α3 electronegative surface. This interaction increases stability and disfavors fibrillation. Independently of this structural effect, the N-terminal electropositive clusters regulate the α-cleavage efficiency. In the fibrillar state, use of circular dichroism, atomic-force and fluorescence microscopies reveal that the N-terminal positive clusters and the α3 electronegative surface dictate the secondary structure, the assembly hierarchy and the growth length of the fibril state. These findings show that the PrP charge structure functions as a code set up to ensure function and reduce pathogenic routes.
Silica bioreplication preserves three-dimensional spheroid structures of human pluripotent stem cells and HepG2 cells
Authors: Lou Yan-Ru , Kanninen Liisa , Kaehr Bryan , Townson Jason L. , Niklander Johanna , Harjumäki Riina , Jeffrey Brinker C. , Yliperttula Marjo 
Published: September 2015

AbstractThree-dimensional (3D) cell cultures produce more in vivo-like multicellular structures such as spheroids that cannot be obtained in two-dimensional (2D) cell cultures. Thus, they are increasingly employed as models for cancer and drug research, as well as tissue engineering. It has proven challenging to stabilize spheroid architectures for detailed morphological examination. Here we overcome this issue using a silica bioreplication (SBR) process employed on spheroids formed from human pluripotent stem cells (hPSCs) and hepatocellular carcinoma HepG2 cells cultured in the nanofibrillar cellulose (NFC) hydrogel. The cells in the spheroids are more round and tightly interacting with each other than those in 2D cultures and they develop microvilli-like structures on the cell membranes as seen in 2D cultures. Furthermore, SBR preserves extracellular matrix-like materials and cellular proteins. These findings provide the first evidence of intact hPSC spheroid architectures and similar fine structures to 2D-cultured cells, providing a pathway to enable our understanding of morphogenesis in 3D cultures.
Selective in vivo and in vitro activities of 3,3′-4-nitrobenzylidene-bis-4-hydroxycoumarin against methicillin-resistant Staphylococcus aureus by inhibition of DNA polymerase III
Authors: Hou Zheng , Zhou Ying , Li Jing , Zhang Xinlei , Shi Xin , Xue Xiaoyan , Li Zhi , Ma Bo , Wang Yukun , Li Mingkai , Luo Xiaoxing 
Published: September 2015

AbstractAs the persistent resistance of Staphylococcus aureus to available antibiotics is associated with high infection incidence, mortality rate and treatment cost, novel antibacterial agents with innovative therapeutic targets must be developed. 3,3′-(4-Nitrobenzylidene)-bis-(4-hydroxycoumarin) (NBH), a dicoumarin derivative, was reported to exert antibacterial activity. This study investigated the underlying mechanisms of in vivo and in vitro activities of NBH against S. aureus. NBH exerted bactericidal effects against the tested S. aureus and Staphylococcus epidermidis strains in vitro, with low cytotoxicity and resistance and high plasma stability. NBH also exhibited therapeutic effects in vivo on septicaemic mice. Results of molecular docking and analysis on morphological change, DNA production and polymerase inhibition suggested that DNA polymerase could be the target of NBH. These findings indicated that dicoumarin derivatives, which interfere with DNA replication, could be developed as a potential agent against S. aureus, particularly methicillin-resistant strains.
Photoluminescence of monovalent indium centres in phosphate glass
Authors: Masai Hirokazu , Yamada Yasuhiro , Okumura Shun , Yanagida Takayuki , Fujimoto Yutaka , Kanemitsu Yoshihiko , Ina Toshiaki 
Published: September 2015

AbstractValence control of polyvalent cations is important for functionalization of various kinds of materials. Indium oxides have been used in various applications, such as indium tin oxide in transparent electrical conduction films. However, although metastable In+ (5 s2 configuration) species exhibit photoluminescence (PL), they have attracted little attention. Valence control of In+ cations in these materials will be important for further functionalization. Here, we describe In+ species using PL and X-ray absorption fine structure (XAFS) analysis. Three absorption bands in the UV region are attributed to the In+ centre: two weak forbidden bands (1S0 → 3P1,1S0 → 3P2) and a strong allowed band (1S0 → 1P1). The strongest PL excitation band cannot be attributed to the conventional allowed transition to the singlet excited state. Emission decay of the order of microseconds suggests that radiative relaxation occurs from the triplet excitation state. The XAFS analysis suggests that these In+ species have shorter In–O distances with lower coordination numbers than in In2O3. These results clearly demonstrate that In+ exists in a metastable amorphous network, which is the origin of the observed luminescent properties.
Transmission and full-band coherent detection of polarization-multiplexed all-optical Nyquist signals generated by Sinc-shaped Nyquist pulses
Authors: Zhang Junwen , Yu Jianjun , Chi Nan 
Published: September 2015

AbstractAll optical method is considered as a promising technique for high symbol rate Nyquist signal generation, which has attracted a lot of research interests for high spectral-efficiency and high-capacity optical communication system. In this paper, we extend our previous work and report the fully experimental demonstration of polarization-division multiplexed (PDM) all-optical Nyquist signal generation based on Sinc-shaped Nyquist pulse with advanced modulation formats, fiber-transmission and single-receiver full-band coherent detection. Using this scheme, we have successfully demonstrated the generation, fiber transmission and single-receiver full-band coherent detection of all-optical Nyquist PDM-QPSK and PDM-16QAM signals up to 125-GBaud. 1-Tb/s single-carrier PDM-16QAM signal generation and full-band coherent detection is realized, which shows the advantage and feasibility of the single-carrier all-optical Nyquist signals.
Increased expression of surface CD44 in hypoxia-DCs skews helper T cells toward a Th2 polarization
Authors: Yang Meixiang , Liu Yanguo , Ren Guangwen , Shao Qianqian , Gao Wenjuan , Sun Jintang , Wang Huayang , Ji Chunyan , Li Xingang , Zhang Yun , Qu Xun 
Published: September 2015

AbstractA low partial oxygen pressure (hypoxia) occurs in many pathological environments, such as solid tumors and inflammatory lesions. Understanding the cellular response to hypoxic stress has broad implications for human diseases. As we previously reported, hypoxia significantly altered dendritic cells (DCs) to a DC2 phenotype and promoted a Th2 polarization of naïve T cells with increased IL-4 production. However, the underlying mechanisms still remain largely unknown. In this study, we found the over-expression of surface CD44 in DCs was involved in this process via ligand binding. Further investigation showed hypoxia could reduce the surface expression of membrane type 1 metalloprotease (MT1-MMP) via down-regulating the kinesin-like protein KIF2A, which subsequently alleviated the shedding of CD44 from DCs. Moreover, KIF2A expression was found negatively regulated by HIF-1α in hypoxic microenvironment. These results suggest a previously uncharacterized mechanism by which hypoxia regulates the function of DCs via KIF2A/MT1-MMP/CD44 axis, providing critical information to understand the immune response under hypoxia.
Trends in (LaMnO3)n/(SrTiO3)m superlattices with varying layer thicknesses
Authors: Jilili J. , Cossu F. , Schwingenschlögl U. 
Published: September 2015

AbstractWe investigate the thickness dependence of the structural, electronic and magnetic properties of (LaMnO3)n/(SrTiO3)m (n, m = 2, 4, 6, 8) superlattices using density functional theory. The electronic structure turns out to be highly sensitive to the onsite Coulomb interaction. In contrast to bulk SrTiO3, strongly distorted O octahedra are observed in the SrTiO3 layers with a systematic off centering of the Ti atoms. The systems favour ferromagnetic spin ordering rather than the antiferromagnetic spin ordering of bulk LaMnO3 and all show half-metallicity, while a systematic reduction of the minority spin band gaps as a function of the LaMnO3 and SrTiO3 layer thicknesses originates from modifications of the Ti dxy states.
5-HTTLPR and use of antidepressants after colorectal cancer including a meta-analysis of 5-HTTLPR and depression after cancer
Authors: Suppli N P , Bukh J D , Moffitt T E , Caspi A , Johansen C , Albieri V , Tjønneland A , Kessing L V , Dalton S O 
Published: September 2015

AbstractThe serotonin-transporter-linked polymorphic region (5-HTTLPR) is one of the most extensively investigated candidates to be involved in gene–environment interaction associated with depression. Nevertheless, the interaction remains controversial. In an original study, we tested the hypothesis that risk for use of antidepressants following a diagnosis of colorectal cancer is associated with bi- and triallelic genotypes of 5-HTTLPR. In addition, in an inclusive meta-analysis, we tested the hypothesis that depression following a diagnosis of cancer is associated with biallelic 5-HTTLPR genotype. We created an exposed-only cohort of 849 colorectal cancer patients from the Danish Diet, Cancer and Health cohort study. The hypothesized association was investigated with Cox regression models and competing risk analyses. Five studies comprising a total of 1484 cancer patients were included in the meta-analysis. Nationwide registries provided information on dates of diagnosis of colorectal cancer and use of antidepressants. Unadjusted odds ratios of depression according to the biallelic 5-HTTLPR genotype were included in the meta-analysis. 5-HTTLPR genotypes were not associated with use of antidepressants after colorectal cancer. Estimated hazard ratios ranged 0.92–1.08, and we observed no statistically significant associations across biallelic and triallelic genotypes in crude as well as adjusted models. The meta-analysis showed no statistically significant associations of 5-HTTLPR biallelic genotype with depression after cancer. Our findings in an original study and a meta-analysis do not support the hypothesis of an association between the 5-HTTLPR genotype and depression after cancer.