bluuebunny/crossref_metadata_2025_split huggingface dataset:
Glucansucrase (mutant) enzymes from Lactobacillus reuteri 180 efficiently transglucosylate Stevia component rebaudioside A, resulting in a superior taste
Authors: te Poele Evelien M. , Devlamynck Tim , Jäger Manuel , Gerwig Gerrit J. , Van de Walle Davy , Dewettinck Koen , Hirsch Anna K. H. , Kamerling Johannis P. , Soetaert Wim , Dijkhuizen Lubbert 
Published: January 2018

AbstractSteviol glycosides from the leaves of the plant Stevia rebaudiana are high-potency natural sweeteners but suffer from a lingering bitterness. The Lactobacillus reuteri 180 wild-type glucansucrase Gtf180-ΔN, and in particular its Q1140E-mutant, efficiently α-glucosylated rebaudioside A (RebA), using sucrose as donor substrate. Structural analysis of the products by MALDI-TOF mass spectrometry, methylation analysis and NMR spectroscopy showed that both enzymes exclusively glucosylate the Glc(β1→C-19 residue of RebA, with the initial formation of an (α1→6) linkage. Docking of RebA in the active site of the enzyme revealed that only the steviol C-19 β-D-glucosyl moiety is available for glucosylation. Response surface methodology was applied to optimize the Gtf180-ΔN-Q1140E-catalyzed α-glucosylation of RebA, resulting in a highly productive process with a RebA conversion of 95% and a production of 115 g/L α-glucosylated products within 3 h. Development of a fed-batch reaction allowed further suppression of α-glucan synthesis which improved the product yield to 270 g/L. Sensory analysis by a trained panel revealed that glucosylated RebA products show a significant reduction in bitterness, resulting in a superior taste profile compared to RebA. The Gtf180-ΔN-Q1140E glucansucrase mutant enzyme thus is an efficient biocatalyst for generating α-glucosylated RebA variants with improved edulcorant/organoleptic properties.
Staphylococcal LTA antagonizes the B cell-mitogenic potential of LPS
Authors: Kang Seok-Seong , Kim Sun Kyung , Baik Jung Eun , Ko Eun Byeol , Ahn Ki Bum , Yun Cheol-Heui , Han Seung Hyun 
Published: January 2018

AbstractLipoteichoic acid (LTA) of Gram-positive bacteria is regarded as the counterpart biomolecule of lipopolysaccharide (LPS) of Gram-negative bacteria because of their structural and immunological similarities. Although LPS induces a strong polyclonal expansion of B cells, little is known about the effect of LTA on B cell proliferation. In the present study, we prepared LTAs from Gram-positive bacteria and examined their effect on splenic B cell proliferation. Unlike LPS, LTA did not induce B cell proliferation. Instead,Staphylococcus aureusLTA (Sa.LTA) appeared to inhibit LPS-induced B cell proliferationin vitro,ex vivo, andin vivomodels. Such effect was observed neither in splenocytes from Toll-like receptor 2 (TLR2)-deficient mice nor in the purified splenic B cells. Furthermore, decreased ERK phosphorylation appeared to be responsible for this phenomenon. Collectively, our results support that Sa.LTA inhibited LPS-induced B cell proliferation through the decrease of ERK phosphorylation via TLR2 signaling pathway.
Force depression following a stretch-shortening cycle is independent of stretch peak force and work performed during shortening
Authors: Fortuna Rafael , Kirchhuebel Hannah , Seiberl Wolfgang , Power Geoffrey A. , Herzog Walter 
Published: January 2018

AbstractThe steady-state isometric force following active muscle shortening or lengthening is smaller (force depression; FD) or greater (residual force enhancement; RFE) than a purely isometric contraction at the corresponding length. The mechanisms behind these phenomena remain not fully understood, with few studies investigating the effects of FD and RFE in stretch-shortening cycles (SSC). The purpose of this study was to investigate the influence of RFE and peak force at the end of the stretch phase on the steady-state isometric force following shortening. Isometric thumb adduction force measurements were preceded by an isometric, a shortening contraction to induce FD, and SSCs at different stretch speeds (15°/s, 60°/s, and 120°/s). The different peak force values at the end of stretch and the different amounts of work performed during shortening did not influence the steady-state isometric force at the end of the SSC. We conclude that the FD following SSC depends exclusively on the amount of RFE established in the initial stretch phase in situations where the timing and contractile conditions of the shortening phase are kept constant .
The Lewis A phenotype is a restriction factor for Rotateq and Rotarix vaccine-take in Nicaraguan children
Authors: Bucardo Filemón , Nordgren Johan , Reyes Yaoska , Gonzalez Fredman , Sharma Sumit , Svensson Lennart 
Published: January 2018

AbstractHisto-blood group antigens (HBGAs) and the Lewis and secretor antigens are associated with susceptibility to rotavirus infection in a genotype-dependent manner. Nicaraguan children were prospectively enrolled in two cohorts vaccinated with either RotaTeq RV5 (n = 68) or Rotarix RV1 (n = 168). Lewis and secretor antigens were determined by saliva phenotyping and genotyping. Seroconversion was defined as a 4-fold increase in plasma IgA antibody titer 1 month after administration of the first dose of the vaccine. Regardless of the vaccine administered, significantly fewer of the children with Lewis A phenotype (0/14) seroconverted after receiving the first vaccine dose compared to 26% (45/175) of those with the Lewis B phenotype and 32% (15/47) of the Lewis negative individuals (P < 0.01). Furthermore, following administration of the RV1 vaccine, secretor-positive ABO blood group B children seroconverted to a significantly lesser extent (5%) compared to secretor-positive children with ABO blood groups A (26%) and O (27%) (P < 0.05). Other factors such as pre-vaccination titers, sex, breastfeeding, and calprotectin levels did not influence vaccine-take. Differences in HBGA expression appear to be a contributing factor in the discrepancy in vaccine-take and thus, in vaccine efficacy in different ethnic populations.
Perovskite Thin Film Synthesised from Sputtered Lead Sulphide
Authors: Silva Filho José Maria Clemente da , Ermakov Viktor A. , Marques Francisco Chagas 
Published: January 2018

AbstractIn the last few years, research on dye-sensitised devices has been focused on the development of solar cells, based on CH3NH3PbX3 (X = I−, Br−, Cl−) composites with perovskite structure. The deposition of perovskite thin films is usually carried out by solution-based processes using spin-coating techniques that result in the production of high quality films. Solar cells made by this method exceed 20% efficiency, with the potential for use in large scale production through ink print or screen printing techniques. As an alternative route, perovskite thin films can be deposited through thermal evaporation. A new method is proposed to produce CH3NH3PbI3, based on a radio-frequency (rf) -sputtering technique that results in a high reproducibility of the films and is compatible with roll-to-roll processes. We deposited thin films of lead-sulphide (PbS) and converted them into perovskite by placing the films in an iodine atmosphere, followed by dipping in a solution of methylammonium iodide (CH3NH3I). The conversions to PbI2 and CH3NH3PbI3 were confirmed by elemental analyses, absorption, and photoluminescence spectroscopy. Structural properties were revealed by X-ray diffraction and infrared and Raman spectroscopy.
Tryptophan hydroxylase (TRH) loss of function mutations induce growth and behavioral defects in Daphnia magna
Authors: Rivetti Claudia , Campos Bruno , Piña Benjamín , Raldúa Demetrio , Kato Yasuhiko , Watanabe Hajime , Barata Carlos 
Published: January 2018

AbstractTryptophan hydroxylase (TRH) is the rate limiting enzyme in the serotonin synthesis. CRISPR-Cas9 technology was used to generate seven indel TRH mutants in Daphnia magna. Mono-allelic indel TRH−/+ clones showed normal levels of serotonin, measured by both immunohistochemistry and mass spectrometry (LC-MS/MS), whereas bi-allelic indel TRH−/− clones showed no detectable levels of serotonin. Life history and behavioral responses of TRH−/− clones showed the anti-phenotype of those exposed to selective serotonin reuptake inhibitors (SSRI). Mutants lacking serotonin grew less and hence reproduced latter, produced smaller clutches of smaller offspring and responded to a greater extent to light than wild type individuals. Mono-allelic indel TRH−/+ individuals showed the intermediate phenotype. The SSRI fluoxetine enhanced offspring production in all clones and decreased the response to light only in those clones having serotonin, thus indication that behavioral effects of this drug in D. magna are associated to serotonin. Results obtained with the TRH mutants are in line with reported ones in TRH knockouts of Caenorhabditis elegans, Drosophila and mice, indicating that there is one gene encoding TRH, which is the serotonin limiting enzyme in both the central and the periphery nervous system in Daphnia and that deprivation of serotonin increases anxiety-like behavior.
Flexibly tunable high-quality-factor induced transparency in plasmonic systems
Authors: Lu Hua , Gan Xuetao , Mao Dong , Jia Baohua , Zhao Jianlin 
Published: January 2018

AbstractThe quality (Q) factor and tunability of electromagnetically induced transparency (EIT)-like effect in plasmonic systems are restrained by the intrinsic loss and weak adjustability of metals, limiting the performance of the devices including optical sensor and storage. Exploring new schemes to realize the high Q-factor and tunable EIT-like effect is particularly significant in plasmonic systems. Here, we present an ultrahigh Q-factor and flexibly tunable EIT-like response in a novel plasmonic system. The results illustrate that the induced transparency distinctly appears when surface plasmon polaritons excited on the metal satisfy the wavevector matching condition with the guided mode in the high-refractive index (HRI) layer. The Q factor of the EIT-like spectrum can exceed 2000, which is remarkable compared to that of other plasmonic systems such as plasmonic metamaterials and waveguides. The position and lineshape of EIT-like spectrum are strongly dependent on the geometrical parameters. An EIT pair is generated in the splitting absorption spectra, which can be easily controlled by adjusting the incident angle of light. Especially, we achieve the dynamical tunability of EIT-like spectrum by changing the Fermi level of graphene inserted in the system. Our results will open a new avenue toward the plasmonic sensing, spectral shaping and switching.
Methylphenidate regulation of osteoclasts in a dose- and sex-dependent manner adversely affects skeletal mechanical integrity
Authors: Uddin Sardar M. Z. , Robison Lisa S. , Fricke Dennis , Chernoff Evan , Hadjiargyrou Michael , Thanos Panayotis K. , Komatsu David E. 
Published: January 2018

AbstractMethylphenidate (MP) is the most prescribed psychostimulant for ADHD patients, with clinically demonstrated detrimental effects on bone quality, potentially leading to early onset osteoporosis and higher fracture risk. The underlying mechanism for the effects of MP on bone remains elusive. This study demonstrates that sex- and dose-dependent effects of MP on bone quality and quantity are mediated by osteoclast activity. Four-week-old male and female rats were treated with low and high dose MP for 13 weeks. Bone quality and quantity were analyzed using microCT, mechanical testing, histomorphometry, and TRAP staining. Male and female rat bone marrow-derived osteoclasts were treated in a dose-dependent manner (0–1000 ng/ml) and osteoclast activity was determined at days 5, 7, and 14 using TRAP staining, as well as a pit formation assay at day 18. Animal studies showed a dose- and a sex-dependent decrease in mechanical integrity in femora and increased TRAP staining in MP-treated rats. Primary cultures revealed that MP had direct dose- and sex-dependent effects on osteoclast activity, as seen by increased differentiation, activity, and resorption. This study demonstrates for the first time that osteoclasts are differentially regulated by MP in adolescent male and female rats, resulting in sex-dependent effects on the skeleton.
Variations among Streptococcus gallolyticus subsp. gallolyticus strains in connection with colorectal cancer
Authors: Kumar Ritesh , Herold Jennifer L. , Taylor John , Xu Juan , Xu Yi 
Published: January 2018

AbstractStreptococcus gallolyticus subsp. gallolyticus (Sg) has long been reported to display a strong association with colorectal cancer (CRC). It was recently demonstrated to actively promote the development of CRC, underscoring the importance of Sg in both clinical correlation and functional relevance in CRC. Here we investigated several clinical isolates of Sg in their interactions with human colon cancer cells and in mouse models. Some Sg strains were able to stimulate host cell proliferation (proliferation-promoting Sg, PP-Sg) whereas others were not (non-proliferation-promoting Sg, NP-Sg). PP-Sg strains adhered to colon cancer cells much better than NP-Sg strains, suggesting that close contact between Sg and host cells is important. In mice, PP-Sg is significantly better at colonizing the colon tissues of A/J mice compared to NP-Sg, however this difference was not observed in C57BL/6 mice, suggesting that Sg colonization of mouse colon tissues involves specific interactions between bacterial and host factors on the colonic epithelium. Finally, in an azoxymethane-induced mouse model of CRC, PP-Sg promoted tumor development whereas NP-Sg did not. These findings provide clues to the mechanism underlying the Sg-CRC association and have important implications to clinical studies that aim to correlate Sg with clinical and pathological features of CRC.
The association between short-term response and long-term survival for cervical cancer patients undergoing neoadjuvant chemotherapy: a system review and meta-analysis
Authors: Kong Shi-yi , Huang Kecheng , Zeng Chao , Ma Xiangyi , Wang Shixuan 
Published: January 2018

AbstractControversy exists regarding whether a short-term response has an impact on the long-term survival of cervical cancer patients undergoing neoadjuvant chemotherapy (NACT). This study was designed to identify the predictive role of an early response by pooling the results of previous studies. The PubMed and Embase databases were searched through July 2016, and the associations between an early response and disease-free survival (DFS) were pooled by hazard ratio (HR) using random effects models. Six studies involving 490 cervical cancer patients, with 336 responders and 154 non-responders, were finally included in the meta-analysis. The HR for 1-year DFS between early responders and non-responders was 0.25 (95% CI 0.10–0.58, P = 0.001). The HRs for 2-, 3-, 4-, and 5-year DFS were 0.28 (95% CI 0.15–0.56), 0.27 (95% CI 0.16–0.45), 0.29 (95% CI 0.17–0.50) and 0.33 (95% CI 0.20–0.54), respectively. No obvious heterogeneity was found among the studies, with I2 = 0, and a sensitivity analysis showed that all pooled results were robust with logHR confidence limits < 0. An early response was associated with DFS, and responders achieved a significantly higher survival rate than non-responders. This finding should be validated in future prospective studies.
Polycomb group protein Suz12 is regulated by a novel miRNA-like small RNA
Authors: Penfornis Patrice , Fernandes Joseph D. , Pochampally Radhika R. 
Published: January 2018

AbstractHuman mesenchymal stem/stromal cells (hMSCs) provide support for cancer progression, partly through their secretome that includes extracellular vesicles (EVs). Based on deep-sequencing of small RNA from EVs of MSCs, we now report the characterization of novel small RNA, named n-miR-G665, which exhibits typical properties of miRNAs. n-miR-G665 sequence is conserved and expressed in most cell types. Knockdown studies using anti-agomirs and shRNA studies demonstrated that n-miR-G665 plays an important role in cell proliferation. Functional assays to reveal the targets of n-miR-G665 showed that polycomb protein Suz12 is regulated by n-miR-G665, which in turn regulates the expression of n-miR-G665 through feedback loop mechanism. These data shed light on a previously unknown novel feedback regulatory mechanism for controlling Suz12 expression regulated by previously not described miRNA, which may highlight a new therapeutic approach to control the polycomb repressor complex 2 activity in cancers.
Environmental pH modulates inerolysin activity via post-binding blockade
Authors: Rampersaud Ryan , Lewis Emma L. , LaRocca Timothy J. , Ratner Adam J. 
Published: January 2018

AbstractThe cholesterol dependent cytolysins (CDCs) are a family of pore-forming toxins produced by a wide range of bacteria. Some CDCs are important virulence factors for their cognate organisms, but their activity must be tightly regulated to ensure they operate at appropriate times and within the appropriate subcellular compartments. pH-dependent activity has been described for several CDCs, but the mechanism of such regulation has been studied in depth only for listeriolysin O (LLO), which senses environmental pH through a triad of acidic residues that mediate protein unfolding. Here we present data supporting a distinct mechanism for pH-dependence for inerolysin (INY), the CDC produced by Lactobacillus iners. Inerolysin (INY) has an acidic pH optimum with loss of activity at neutral pH. INY pH-dependence is characterized by reversible loss of pore formation with preservation of membrane binding. Fluorescent membrane probe assays indicated that INY insertion into host cell membranes, but not oligomerization, was defective at neutral pH. These data support the existence of a newly appreciated form of CDC pH-dependence functioning at a late stage of pore formation.
Earthquake impacts on microcrustacean communities inhabiting groundwater-fed springs alter species-abundance distribution patterns
Authors: Fattorini Simone , Di Lorenzo Tiziana , Galassi Diana M. P. 
Published: January 2018

AbstractEarthquakes are important natural events, yet their impacts on animal communities are poorly known. Understanding earthquake impacts on groundwater communities is essential to assess their resilience and hence to perform conservation actions. We investigated how a 6.3 Mw earthquake that occurred in 2009 altered the community structure (diversity, evenness, dominance, species abundance distributions and beta-diversity) of microcrustaceans (Crustacea Copepoda) inhabiting springs fed by the Gran Sasso Aquifer (Central Italy). Sampling was done in low-discharge (1997), high-discharge (2005), and post-seismic (2012) hydrological years. Stygobites (obligate groundwater species) and non-stygobites (non-obligate groundwater species) showed different patterns. A high-water discharge in 2005 altered abundance patterns of non-stygobites. The earthquake re-established former abundance patterns. Stygobites were less affected by high-water discharge in 2005, and showed strong increases in diversity and evenness after the earthquake. This effect was due to the fact that the earthquake induced a strong population decline of previously dominant stygobites (especially of Nitocrella pescei) in the aquifer, and subsequently at the main spring outlets, thus allowing a more equitable species-abundance distribution. These results highlight the importance of considering species ecology to understand the effects of a significant earthquake event on animal communities.
Conformational folding and disulfide bonding drive distinct stages of protein structure formation
Authors: Lv Jian-Min , Lü Shou-Qin , Liu Zu-Pei , Zhang Juan , Gao Bo-Xuan , Yao Zhen-Yu , Wu Yue-Xin , Potempa Lawrence A. , Ji Shang-Rong , Long Mian , Wu Yi 
Published: January 2018

AbstractThe causal relationship between conformational folding and disulfide bonding in protein oxidative folding remains incompletely defined. Here we show a stage-dependent interplay between the two events in oxidative folding of C-reactive protein (CRP) in live cells. CRP is composed of five identical subunits, which first fold spontaneously to a near-native core with a correctly positioned C-terminal helix. This process drives the formation of the intra-subunit disulfide bond between Cys36 and Cys97. The second stage of subunit folding, however, is a non-spontaneous process with extensive restructuring driven instead by the intra-subunit disulfide bond and guided by calcium binding-mediated anchoring. With the folded subunits, pentamer assembly ensues. Our results argue that folding spontaneity is the major determinant that dictates which event acts as the driver. The stepwise folding pathway of CRP further suggests that one major route might be selected out of the many in theory for efficient folding in the cellular environment.
Hotspot relaxation time of NbN superconducting nanowire single-photon detectors on various substrates
Authors: Zhang Lu , You Lixing , Yang Xiaoyan , Wu Junjie , Lv Chaolin , Guo Qi , Zhang Weijun , Li Hao , Peng Wei , Wang Zhen , Xie Xiaoming 
Published: January 2018

AbstractHotspot relaxation time (τ
th
) is one of the essential parameter which defines the maximum count rate of superconducting nanowire single-photon detectors (SNSPDs). We studied the τ
th
for NbN-based SNSPDs on various substrates using the two-photon detection method based on the pump-probe spectroscopy technique. We observed that τ
th
strongly increased with increasing bias current in the two-photon detection regime. In addition, the minimum hotspot relaxation time (τ
th
)min was not significantly affected by the bath temperature; this is different from the previous observations reported for WSi SNSPDs. In addition, a strong dependency of (τ
th
)min on the substrate was found. The minimum (τ
th
)min was 11.6 ps for SNSPDs made of 5.5-nm-thick NbN on MgO (100), whereas the maximum (τ
th
)min was 34.5 ps for SNSPDs made of 7.5-nm-thick NbN on Si (100). We presented a direct correlation between the values of τ
th
and degrees of disorder of NbN films grown on different substrates.
Combined analysis of the salivary microbiome and host defence peptides predicts dental disease
Authors: Simon-Soro A. , Sherriff A. , Sadique S. , Ramage G. , Macpherson L. , Mira A. , Culshaw S. , Malcolm J. 
Published: January 2018

AbstractUnderstanding the triad of host response, microbiome and disease status is potentially informative for disease prediction, prevention, early intervention and treatment. Using longitudinal assessment of saliva and disease status, we demonstrated that partial least squares modelling of microbial, immunological and clinical measures, grouped children according to future dental disease status. Saliva was collected and dental health assessed in 33 children aged 4 years, and again 1-year later. The composition of the salivary microbiome was assessed and host defence peptides in saliva were quantified. Principal component analysis of the salivary microbiome indicated that children clustered by age and not disease status. Similarly, changes in salivary host defence peptides occurred with age and not in response to, or preceding dental caries. Partial least squares modelling of microbial, immunological and clinical baseline measures clustered children according to future dental disease status. These data demonstrate that isolated evaluation of the salivary microbiome or host response failed to predict dental disease. In contrast, combined assessment of both host response together with the microbiome revealed clusters of health and disease. This type of approach is potentially relevant to myriad diseases that are modified by host–microbiome interactions.