bluuebunny/crossref_metadata_2025_split huggingface dataset:
Biosynthesis of the antibiotic nonribosomal peptide penicillin in baker’s yeast
Authors: Awan Ali R. , Blount Benjamin A. , Bell David J. , Shaw William M. , Ho Jack C.H. , McKiernan Robert M. , Ellis Tom 
Published: May 2017

AbstractFungi are a valuable source of enzymatic diversity and therapeutic natural products including antibiotics. Here we engineer the baker’s yeast Saccharomyces cerevisiae to produce and secrete the antibiotic penicillin, a beta-lactam nonribosomal peptide, by taking genes from a filamentous fungus and directing their efficient expression and subcellular localization. Using synthetic biology tools combined with long-read DNA sequencing, we optimize productivity by 50-fold to produce bioactive yields that allow spent S. cerevisiae growth media to have antibacterial action against Streptococcus bacteria. This work demonstrates that S. cerevisiae can be engineered to perform the complex biosynthesis of multicellular fungi, opening up the possibility of using yeast to accelerate rational engineering of nonribosomal peptide antibiotics.
Artificial gravity field, astrophysical analogues, and topological phase transitions in strained topological semimetals
Authors: Guan Shan , Yu Zhi-Ming , Liu Ying , Liu Gui-Bin , Dong Liang , Lu Yunhao , Yao Yugui , Yang Shengyuan A. 
Published: May 2017

AbstractEffective gravity and gauge fields are emergent properties intrinsic for low-energy quasiparticles in topological semimetals. Here, taking two Dirac semimetals as examples, we demonstrate that applied lattice strain can generate warped spacetime, with fascinating analogues in astrophysics. Particularly, we study the possibility of simulating black-hole/white-hole event horizons and gravitational lensing effect. Furthermore, we discover strain-induced topological phase transitions, both in the bulk materials and in their thin films. Especially in thin films, the transition between the quantum spin Hall and the trivial insulating phases can be achieved by a small strain, naturally leading to the proposition of a novel piezo-topological transistor device. Possible experimental realizations and analogue of Hawking radiation effect are discussed. Our result bridges multiple disciplines, revealing topological semimetals as a unique table-top platform for exploring interesting phenomena in astrophysics and general relativity; it also suggests realistic materials and methods to achieve controlled topological phase transitions with great potential for device applications.
Nexus fermions in topological symmorphic crystalline metals
Authors: Chang Guoqing , Xu Su-Yang , Huang Shin-Ming , Sanchez Daniel S. , Hsu Chuang-Han , Bian Guang , Yu Zhi-Ming , Belopolski Ilya , Alidoust Nasser , Zheng Hao , Chang Tay-Rong , Jeng Horng-Tay , Yang Shengyuan A. , Neupert Titus , Lin Hsin , Hasan M. Zahid 
Published: May 2017

AbstractTopological metals and semimetals (TMs) have recently drawn significant interest. These materials give rise to condensed matter realizations of many important concepts in high-energy physics, leading to wide-ranging protected properties in transport and spectroscopic experiments. It has been well-established that the known TMs can be classified by the dimensionality of the topologically protected band degeneracies. While Weyl and Dirac semimetals feature zero-dimensional points, the band crossing of nodal-line semimetals forms a one-dimensional closed loop. In this paper, we identify a TM that goes beyond the above paradigms. It shows an exotic configuration of degeneracies without a well-defined dimensionality. Specifically, it consists of 0D nexus with triple-degeneracy that interconnects 1D lines with double-degeneracy. We show that, because of the novel form of band crossing, the new TM cannot be described by the established results that characterize the topology of the Dirac and Weyl nodes. Moreover, triply-degenerate nodes realize emergent fermionic quasiparticles not present in relativistic quantum field theory. We present materials candidates. Our results open the door for realizing new topological phenomena and fermions including transport anomalies and spectroscopic responses in metallic crystals with nontrivial topology beyond the Weyl/Dirac paradigm.
Establishment of induced pluripotent stem cells from normal B cells and inducing AID expression in their differentiation into hematopoietic progenitor cells
Authors: Kawamura Fumihiko , Inaki Makoto , Katafuchi Atsushi , Abe Yu , Tsuyama Naohiro , Kurosu Yumiko , Yanagi Aki , Higuchi Mitsunori , Muto Satoshi , Yamaura Takumi , Suzuki Hiroyuki , Noji Hideyoshi , Suzuki Shinichi , Yoshida Mitsuaki A. , Sasatani Megumi , Kamiya Kenji , Onodera Masafumi , Sakai Akira 
Published: May 2017

AbstractB cell derived induced pluripotent stem cells (BiPSCs) were recently established from peripheral blood B cells by the simultaneous transfection of Yamanaka factors (Oct3/4, Sox2, Klf4, c-Myc) and C/EBPα using a Sendai virus vector. Here, using a different method, we established BiPSCs with immunoglobulin heavy chain (IgH) gene rearrangement from normal B cells purified from lymph nodes. The critical points of our method are pre-stimulation of B cells with IL-21 and CD40-ligand (CD40L), followed by consecutive transfection of highly concentrated Yamanaka factors using a retroviral vector. Following each transfection the cells were centrifuged onto a retronectin coated plate and the activated by IL-4, IL-2, and CD40L. Furthermore, we established BiPSCs (BiPSC-A) in which activation-induced cytidine deaminase (AID) could be induced using the doxycycline-controlled. Both the parental BiPSC and BiPSC-A showed the capability of differentiating into hematopoietic progenitor cells (HPCs) based on confirmation of CD34 expression and colony-formation from CD34-positive cells. The findings that BiPSC-A can differentiate into HPCs suggest that there is a possibility that induction of AID expression would result in chromosomal translocations in the process of differentiation from BiPSCs, and therefore that these BiPSCs could be useful in elucidating the tumor origin of abnormal B cells in myelomagenesis.
Nanoscale Brownian heating by interacting magnetic dipolar particles
Authors: Chalopin Yann , Bacri Jean-Claude , Gazeau Florence , Devaud Martin 
Published: May 2017

AbstractClusters of magnetic nanoparticles have received considerable interest in various research fields. Their capacity to generate heat under an alternating magnetic field has recently opened the way to applications such as cancer therapy by hyperthermia. This work is an attempt to investigate the collective effects of interacting dipoles embedded in magnetic nano-particles (MNP) to predict their thermal dissipation with a liquid. We first present a general approach, based on the tracking of the microscopic dipole fluctuations, to access to the dissipation spectra of any spatial distribution of MNPs. Without any other assumption that the linear response regime, it is shown that increasing the particle concentration (dipolar interactions) dramatically diminishes and blueshifts the dissipation processes. This effect originates in a predominance of the coupling energy over the Brownian torques, which create a long-range ordering that saturates the response of the system to an external field. Consequently, the particle density is of fundamental importance to the control of the absorption of electromagnetic energy and its subsequent dissipation in the form of heat.
An Aqueous-Based Approach for Fabrication of PVDF/MWCNT Porous Composites
Authors: Rezvantalab Hossein , Ghazi Nastaran , Ambrusch Matthew J. , Infante Jeffrey , Shojaei-Zadeh Shahab 
Published: May 2017

AbstractIn this paper, we demonstrate the fabrication of conductive porous polymers based on foaming of an aqueous dispersion of polymeric particles and multi-walled carbon nanotubes (CNT). By tuning the surface energy of the constituents, we direct their preferential adsorption at the air-liquid (bubble) interface or within the liquid film between the bubbles. Sintering this bi-constituent foam yields solid closed-cell porous structure which can be electrically conductive if CNT are able to form a conductive path. We measure transport (electrical and thermal), mechanical, and morphological properties of such porous structures as a function of CNT loading and the method used for their surface functionalization. For a fixed polymer volume fraction, we demonstrate the limit in which increasing CNT results in decreasing the mechanical strength of the sample due to lack of adequate polymer-CNT bond. Such lightweight conductive porous composites are considered in applications including EMI shielding, electrostatic discharge protection, and electrets.
Hepatitis B Virus e Antigen Activates the Suppressor of Cytokine Signaling 2 to Repress Interferon Action
Authors: Yu Yi , Wan Pin , Cao Yanhua , Zhang Wei , Chen Junbo , Tan Li , Wang Yan , Sun Zhichen , Zhang Qi , Wan Yushun , Zhu Ying , Liu Fang , Wu Kailang , Liu Yingle , Wu Jianguo 
Published: May 2017

AbstractHepatitis B virus (HBV) infection causes acute hepatitis B (AHB), chronic hepatitis B (CHB), liver cirrhosis (LC), and eventually hepatocellular carcinoma (HCC). The presence of hepatitis B e antigen (HBeAg) in the serum generally indicates ongoing viral replication and disease progression. However, the mechanism by which HBeAg regulates HBV infection remains unclear. Interferons (IFNs) are pleiotropic cytokines that participate in host innate immunity. After binding to receptors, IFNs activate the JAK/STAT pathway to stimulate expression of IFN-stimulated genes (ISGs), leading to induction of antiviral responses. Here, we revealed that HBeAg represses IFN/JAK/STAT signaling to facilitate HBV replication. Initially, HBeAg stimulates the expression of suppressor of cytokine signaling 2 (SOCS2). Subsequently, SOCS2 impairs IFN/JAK/STAT signaling through reducing the stability of tyrosine kinase 2 (TYK2), downregulating the expression of type I and III IFN receptors, attenuating the phosphorylation and nucleus translocation of STAT1. Finally, SOCS2 inhibits the expression of ISGs, which leads to the repression of IFN action and facilitation of viral replication. These results demonstrate an important role of HBeAg in the regulation of IFN action, and provide a possible molecular mechanism by which HBV resists the IFN therapy and maintains persistent infection.
The association between psychological stress and miscarriage: A systematic review and meta-analysis
Authors: Qu Fan , Wu Yan , Zhu Yu-Hang , Barry John , Ding Tao , Baio Gianluca , Muscat Ruth , Todd Brenda K. , Wang Fang-Fang , Hardiman Paul J 
Published: May 2017

AbstractThis systematic review and meta-analysis was designed to investigate whether maternal psychological stress and recent life events are associated with an increased risk of miscarriage. A literature search was conducted to identify studies reporting miscarriage in women with and without history of exposure to psychological stress (the only exposure considered). The search produced 1978 studies; 8 studies were suitable for analysis. A meta-analysis was performed using a random-effects model with effect sizes weighted by the sampling variance. The risk of miscarriage was significantly higher in women with a history of exposure to psychological stress (OR 1.42, 95% CI 1.19–1.70). These findings remained after controlling for study type (cohort and nested case-control study OR 1.33 95% CI 1.14–1.54), exposure types (work stress OR 1.27, 95% CI 1.10–1.47), types of controls included (live birth OR 2.82 95% CI: 1.64–4.86). We found no evidence that publication bias or study heterogeneity significantly influenced the results. Our finding provides the most robust evidence to date, that prior psychological stress is harmful to women in early pregnancy.
Hormonal pleiotropy helps maintain queen signal honesty in a highly eusocial wasp
Authors: Oliveira Ricardo Caliari , Vollet-Neto Ayrton , Akemi Oi Cintia , van Zweden Jelle S. , Nascimento Fabio , Sullivan Brent Colin , Wenseleers Tom 
Published: May 2017

AbstractIn insect societies, both queens and workers produce chemicals that reliably signal caste membership and reproductive status. The mechanisms that help to maintain the honesty of such queen and fertility signals, however, remain poorly studied. Here we test if queen signal honesty could be based on the shared endocrine control of queen fertility and the production of specific signals. In support of this “hormonal pleiotropy” hypothesis, we find that in the common wasp, application of methoprene (a juveline hormone analogue) caused workers to acquire a queen-like cuticular hydrocarbon profile, resulting in the overproduction of known queen pheromones as well as some compounds typically linked to worker fertility. By contrast, administration of precocene-I (a JH inhibitor) had a tendency to have the opposite effect. Furthermore, a clear gonadotropic effect of JH in queens was suggested by the fact that circulating levels of JH were ca. 2 orders of magnitude higher in queens than those in workers and virgin, non-egg-laying queens, even if methoprene or precocene treatment did not affect the ovary development of workers. Overall, these results suggest that queen signal honesty in this system is maintained by queen fertility and queen signal production being under shared endocrine control.
Exploring the link between cadmium and psoriasis in a nationally representative sample
Authors: Liaw Fang-Yih , Chen Wei-Liang , Kao Tung-Wei , Chang Yaw-Wen , Huang Ching-Fu 
Published: May 2017

AbstractPsoriasis, a skin inflammatory disease, originates from dysregulated interactions of the immune system. Cadmium, an environment pollutant, increases the levels of inflammation markers and influences the immune system. To clarify the relationship between cadmium and psoriasis, 5,927 participants, ≥20 years, in the National Health and Nutrition Examination Survey (NHANES) 2003–2006 were studied. Psoriasis severity was assessed using self-reported dermatology questionnaires. Cadmium was measured using blood chemistry. Three adjusted models were applied for the interaction between serum cadmium and severity of psoriasis. Psoriasis patients had significantly higher blood cadmium (0.67 vs. 0.52 μg/L,p = 0.006). There was a strong linear increase in predicted blood cadmium values with an increase in severity of psoriasis (pfor trend = 0.002). The β coefficient of the predicted serum cadmium in the “few patches to extensive psoriasis” group was 0.234 (p = 0.002) after adjusting covariates. Participants with severe psoriasis have higher blood cadmium. Environmental exposure to cadmium can predispose to the worsening of psoriasis. Although there are still limitations in this study, such as not included treatment data, these results have substantial public health implications for the general population, as they demonstrate the importance of cadmium exposure prevention, particularly among psoriasis patients.
Unexpected Efficacy of a Novel Sodium Channel Modulator in Dravet Syndrome
Authors: Anderson Lyndsey L. , Hawkins Nicole A. , Thompson Christopher H. , Kearney Jennifer A. , George Alfred L. 
Published: May 2017

AbstractDravet syndrome, an epileptic encephalopathy affecting children, largely results from heterozygous loss-of-function mutations in the brain voltage-gated sodium channel gene SCN1A. Heterozygous Scn1a knockout (Scn1a+/−) mice recapitulate the severe epilepsy phenotype of Dravet syndrome and are an accepted animal model. Because clinical observations suggest conventional sodium channel blocking antiepileptic drugs may worsen the disease, we predicted the phenotype of Scn1a+/− mice would be exacerbated by GS967, a potent, unconventional sodium channel blocker. Unexpectedly, GS967 significantly improved survival of Scn1a+/− mice and suppressed spontaneous seizures. By contrast, lamotrigine exacerbated the seizure phenotype. Electrophysiological recordings of acutely dissociated neurons revealed that chronic GS967-treatment had no impact on evoked action potential firing frequency of interneurons, but did suppress aberrant spontaneous firing of pyramidal neurons and was associated with significantly lower sodium current density. Lamotrigine had no effects on neuronal excitability of either neuron subtype. Additionally, chronically GS967-treated Scn1a+/− mice exhibited normalized pyramidal neuron sodium current density and reduced hippocampal NaV1.6 protein levels, whereas lamotrigine treatment had no effect on either pyramidal neuron sodium current or hippocampal NaV1.6 levels. Our findings demonstrate unexpected efficacy of a novel sodium channel blocker in Dravet syndrome and suggest a potential mechanism involving a secondary change in NaV1.6.
Structural Basis for Importin-α Binding of the Human Immunodeficiency Virus Tat
Authors: Smith K. M. , Himiari Z. , Tsimbalyuk S. , Forwood J. K. 
Published: May 2017

AbstractHIV-1 has caused 35 million deaths globally, and approximately the same number is currently living with HIV-1. The trans-activator of transcription (Tat) protein of HIV-1 plays an important regulatory function in the virus life cycle, responsible for regulating the reverse transcription of the viral genome RNA. Tat is found in the nucleus of infected cells, but can also invade uninfected neighbouring cells. Regions within Tat responsible for these cellular localisations are overlapping and include a nuclear localisation signal (NLS) spanning 48GRKKRR, and a cell penetrating peptide (CPP) signal spanning 48GRKKRRQRRRAPQN. However, the mechanism by which this NLS/CPP region mediates interaction with the nuclear import receptors remains to be resolved structurally. Here, we establish that the HIV-1 Tat:NLS/CPP is able to form a stable and direct interaction with the classical nuclear import receptor importin-α and using x-ray crystallography, we have determined the molecular interface and binding determinants to a resolution of 2.0 Å. We show for the first time that the interface is the same as host factors such as Ku70 and Ku80, rather than other virus proteins such as Ebola VP24 that bind on the outer surface of importin-α.
Rapid face adaptation distributes representation in inferior-temporal cortex across time and neuronal dimensions
Authors: Vahabie Abdol-Hossein , Dehaqani Mohammad-Reza A. , Ahmadabadi Majid Nili , Araabi Babak Nadjar , Esteky Hossein 
Published: May 2017

AbstractNeuronal networks of the brain adapt their information processing according to the history of stimuli. Whereas most studies have linked adaptation to repetition suppression, recurrent connections within a network and disinhibition due to adaptation predict more complex response patterns. The main questions of this study are as follows: what is the effect of the selectivity of neurons on suppression/enhancement of neural responses? What are the consequences of adaptation on information representation in neural population and the temporal structure of response patterns? We studied rapid face adaptation using spiking activities of neurons in the inferior-temporal (IT) cortex. Investigating the responses of neurons, within a wide range from negative to positive face selectivity, showed that despite the peak amplitude suppression in highly positive selective neurons, responses were enhanced in most other neurons. This enhancement can be attributed to disinhibition due to adaptation. Delayed and distributed responses were observed for positive selective neurons. Principal component analysis of the IT population responses over time revealed that repetition of face stimuli resulted in temporal decorrelation of the network activity. The contributions of the main and higher neuronal dimensions were changed under an adaptation condition, where more neuronal dimensions were used to encode repeated face stimuli.
DMBA acts on cumulus cells to desynchronize nuclear and cytoplasmic maturation of pig oocytes
Authors: Song Zhi-Qiang , Li Xuan , Wang Yan-Kui , Du Zhi-Qiang , Yang Cai-Xia 
Published: May 2017

AbstractAs an environmental pollutant and carcinogen, 7,12-dimethylbenz[a]anthracene (DMBA) can destroy ovarian follicles at all developmental stages in rodents. However, the underlying molecular mechanism remains obscure. In the present study, we aim to address how DMBA affects the in vitro maturation and development of porcine oocytes. We discovered that for 20 μM DMBA-treated cumulus-oocyte complexes (COCs), the rate of oocyte germinal vesicle breakdown (GVBD) was significantly altered, and the extrusion rate of first polar body was increased. Moreover, oocytes from 20 μM DMBA-treated COCs had significant down-regulation of H3K9me3 and H3K27me3, up-regulation of H3K36me3, higher incidence of DNA double strand breaks (DSBs) and early apoptosis. In striking contrast, none of these changes happened to 20 μM DMBA-treated cumulus-denuded oocytes (CDOs). Furthermore, 20 μM DMBA treatment increased the reactive oxygen species (ROS) level, decreased mitochondrial membrane potential (Δ Ψm), and inhibited developmental competence for oocytes from both COC and CDO groups. Collectively, our data indicate DMBA could act on cumulus cells via the gap junction to disturb the synchronization of nuclear and ooplasmic maturation, and reduce the developmental competence of oocytes.
Characterization of Product and Potential Mechanism of Cr(VI) Reduction by Anaerobic Activated Sludge in a Sequencing Batch Reactor
Authors: Jin Ruofei , Liu Yao , Liu Guangfei , Tian Tian , Qiao Sen , Zhou Jiti 
Published: May 2017

AbstractBioremediation of Cr(VI) and nitrate is considered as a promising and cost-effective alternative to chemical and physical methods. However, organo-Cr(III) complexes in effluent generally causes environmental concerns due to second-pollution. Here, Cr(VI) reduction and immobilization efficiencies of anaerobic activated sludge were investigated. Anaerobic activated sludge showed strong reduction ability of Cr(VI) and possessed a great potential of Cr(III) immobilization. Almost 100.0 mg l−1Cr(VI) could be completely reduced and immobilized by anaerobic activated sludge in a sequencing batch reactor in 24 h. And most generated Cr(III) was accumulated outside of sludge cells. Extracellular polymeric substances (EPS) could bind to Cr(VI) and form EPS-Cr(VI) interaction to reduce the toxic effect of Cr(VI) and promote the Cr(VI) reduction. Protein-like and humic-like substances were responsible for binding with Cr(VI), meanwhile the process was a thermodynamically favorable binding reaction. Then Cr(VI) was reduced to Cr(III) by membrane-associated chromate reductase of sludge. Eventually, the generated Cr(III) might exist as poly-nuclear Cr(III) complexes adhered to sludge surfaces.