Label-Free Electrochemical Immunosensor Based on a Functionalized Ionic Liquid and Helical Carbon Nanotubes for the Determination of Cardiac Troponin I

A label-free electrochemical immunosensor for cardiac troponin I was prepared by using a helical carbon nanotube-supported aldehyde-functionalized ionic liquid. Because of the good conductivity of ionic liquid and helical carbon nanotubes, high sensitivity of the immunosensor was obtained. Functionalized ionic liquid provided binding sites for antibody, which simplified the process of sensor construction. Cardiac troponin I was detected by this immunosensor with a linear range of 0.05-30 ng/mL and a detection limit of 0.03 ng/mL. The electrochemical immunosensor had satisfactory reproducibility, high sensitivity, and acceptable specificity.

Involvement of Lhcb6 and Lhcb5 in Photosynthesis Regulation in Physcomitrella patens Response to Abiotic Stress

There are a number of highly conserved photosystem II light-harvesting antenna proteins in moss whose functions are unclear. Here, we investigated the involvement of chlorophyll-binding proteins, Lhcb6 and Lhcb5, in light-harvesting and photosynthesis regulation in Physcomitrella patens. Lhcb6 or Lhcb5 knock-out resulted in a disordered thylakoid arrangement, a decrease in the number of grana membranes, and an increase in the number of starch granule. The absence of Lhcb6 or Lhcb5 did not noticeably alter the electron transport rates. However, the non-photochemical quenching activity in the lhcb5 mutant was dramatically reduced when compared to wild-type or lhcb6 plants under abiotic stress. Lhcb5 plants were more sensitive to photo-inhibition, while lhcb6 plants showed little difference compared to the wild-type plants under high-light stress. Moreover, both mutants showed a growth malformation phenotype with reduced chlorophyll content in the gametophyte. These results suggested that Lhcb6 or Lhcb5 played a unique role in plant development, thylakoid organization, and photoprotection of PSII in Physcomitrella, especially when exposed to high light or osmotic environments.

Corrosion Acceleration of Printed Circuit Boards With an Immersion Silver Layer Exposed to Bacillus cereus in an Aerobic Medium

In this research, the corrosion behavior of printed circuit boards with an immersion silver layer (PCB-ImAg) exposed to Bacillus cereus bacteria in Luria-Bertani broth was investigated. The growth test demonstrated that B. cereus had a high copper tolerance. Analysis of surface and cross-sectional view of the samples after immersion test indicated that metabolites produced by B. cereus accelerated the microporous corrosion of PCB-ImAg, and the biofilm that adhered to the surface led to oxygen concentration corrosion. Electrochemical impedance spectroscopy tests confirmed that the microbiologically influenced corrosion of PCB-ImAg was related to the biofilm formation and metabolism.

Transcription factor WRKY30 mediates resistance to Cucumber mosaic virus in Arabidopsis

WRKY transcription factors are key regulators in regulating abiotic or biotic stress response in Arabidopsis. Previous studies showed that WRKY30 expression was induced by oxidative stress treatment, fungal elicitor, SA and ABA. However, functions of WRKY30 on viral defense are not well studied. Here, we found that Arabidopsis WRKY DNA binding protein 30 (WRKY30) plays essential roles in regulating Cucumber mosaic virus (CMV) resistance. The expression of WRKY30 was induced by CMV infection and wrky30 mutant displayed more susceptibility (including higher oxidative damages, induced reactive oxygen species synthesis and more PSII photochemistry compromise), while WRKY30 overexpression plants (WRKY30OX) exhibited more resistance to CMV infection. Moreover BRs-induced CMV tolerance is partly dependent on WRKY30. And WRKY30 expression increased after BL treatment. All these demonstrated that WRKY30 works as a positive regulator in plant CMV resistance process.

Cas9-NG Greatly Expands the Targeting Scope of the Genome-Editing Toolkit by Recognizing NG and Other Atypical PAMs in Rice

CRISPR technologies enabling precise genome manipulation are valuable for gene function studies and molecular crop breeding. However, the requirement of a protospacer adjacent motif (PAM), such as NGG and TTN, for Cas protein recognition restricts the selection of targetable genomic loci in practical applications of CRISPR technologies. Recently Cas9-NG, which recognizes a minimal NG PAM, was reported to expand the targeting space of genome editing in human cells, but it remains unclear whether this Cas9 variant can be used in plants. In this study, we evaluated the nuclease activity of Cas9-NG toward various NGN PAMs by targeting endogenous genes in transgenic rice. We found that Cas9-NG edits all NGG, NGA, NGT, and NGC sites with impaired activity, while the gene-edited plants were dominated by monoallelic mutations. Cas9-NG-engineered base editors were then developed and used to generate OsBZR1 gain-of-function plants that can not be created by other available Cas9-engineered base editors. Moreover, we showed that a Cas9-NG-based transcriptional activator efficiently upregulated the expression of endogenous target genes in rice. In addition, we discovered that Cas9-NG recognizes NAC, NTG, NTT, and NCG apart from NG PAM. Together, these findings demonstrate that Cas9-NG can greatly expand the targeting scope of genome-editing tools, showing great potential for targeted genome editing, base editing, and genome regulation in plants.

A room-temperature ferroelectric semimetal

Coexistence of reversible polar distortions and metallicity leading to a ferroelectric metal, first suggested by Anderson and Blount in 1965, has so far remained elusive. Electrically switchable intrinsic electric polarization, together with the direct observation of ferroelectric domains, has not yet been realized in a bulk crystalline metal, although incomplete screening by mobile conduction charges should, in principle, be possible. Here, we provide evidence that native metallicity and ferroelectricity coexist in bulk crystalline van der Waals WTe₂ by means of electrical transport, nanoscale piezoresponse measurements, and first-principles calculations. We show that, despite being a Weyl semimetal, WTe₂ has switchable spontaneous polarization and a natural ferroelectric domain structure at room temperature. This new class of materials has tantalizing potential for functional nanoelectronics applications.

Co-administration of combretastatin A4 nanoparticles and sorafenib for systemic therapy of hepatocellular carcinoma

Effective systemic therapy is highly desired for the treatment of hepatocellular carcinoma (HCC). In this study, a combination of nanoparticles of poly(L-glutamic acid)-graft-methoxy poly(ethylene glycol)/combretastatin A4 sodium salt (CA4-NPs) plus sorafenib is developed for the cooperative systemic treatment of HCC. The CA4-NPs leads to the disruption of established tumor blood vessels and extensive tumor necrosis, however, inducing increased expression of VEGF-A and angiogenesis. Sorafenib reduces the VEGF-A induced angiogenesis and further inhibits tumor proliferation, cooperating with the CA4-NPs. A significant decrease in tumor volume and prolonged survival time are observed in the combination group of CA4-NPs plus sorafenib compared with CA4-NPs or sorafenib monotherapy in subcutaneous and orthotopic H22 hepatic tumor models. Seventy-one percent of the mice are alive without residual tumor at 96 days post tumor inoculation for the subcutaneous models treated with CA4-NPs 30 or 35 mg·kg^-1 plus sorafenib 30 mg·kg^-1. Our findings suggest that co-administration of sorafenib and CA4-NPs possesses significant antitumor efficacy for HCC treatment. STATEMENT OF SIGNIFICANCE: Effective systemic therapy is highly desired for the treatment of hepatocellular carcinoma (HCC). Herein, we demonstrate that a combination of nanoparticles of poly(L-glutamic acid)-graft-methoxy poly(ethylene glycol)/combretastatin A4 sodium salt (CA4-NPs) plus sorafenib is a promising synergistic approach for systemic treatment of HCC. The CA4-NPs leads to the disruption of established tumor blood vessels and extensive tumor necrosis, however, inducing increased expression of VEGF-A and angiogenesis. Sorafenib reduces the VEGF-A induced angiogenesis and further inhibits tumor proliferation, cooperating with the CA4-NPs.

PI3Kgamma Inhibitor Attenuates Immunosuppressive Effect of Poly(l-Glutamic Acid)-Combretastatin A4 Conjugate in Metastatic Breast Cancer

Vascular disrupting agents (VDAs) have great potential for cancer treatment. Poly(l-glutamic acid)-combretastatin A4 conjugate (PLG-CA4) is a novel class of VDAs. Though it has notable antitumor activity, it can induce host immune responses that promote tumor growth. Here, PLG-CA4 induces the polarization of tumor-associated macrophages (TAMs) toward the M2-like phenotype in 4T1 metastatic breast cancer (Control 30% vs PLG-CA4 53%; p < 0.05). Compared to the monotherapy of PLG-CA4, inhibition of phosphoinositide 3-kinase gamma (PI3Kγ) attenuates the immunosuppressive effect of PLG-CA4 treatment by decreasing the number of M2-like TAMs (2.0 × 104 to 1.5 × 104 per tumor) and potential enhancement of cytotoxic T lymphocyte (3.0 × 104 to 5.7 × 104 per tumor). Importantly, PI3Kγ inhibitor synergizing with PLG-CA4 significantly extends the mean survival time from 52 days in monotherapy-treated mice to 61.8 days. Additionally, the combination of PLG-CA4 and PI3Kγ inhibitor improves the tumor therapeutic effect of NLG919, an inhibitor of immune checkpoint indoleamine 2,3-dioxygenase (IDO). As far as it is known, this is the first demonstrated study that VDAs induce the reshaping of macrophages to the M2-like phenotype. The findings also indicate a potential therapeutic strategy of the combination VDAs with an accurate immune modifier in the tumor to reverse the immune resistance.

Chlorine-Doped Graphene Quantum Dots with Enhanced Anti- and Pro-Oxidant Properties

Production or elimination of highly reactive oxygen species is critical in antioxidant, photodynamic, therapeutic, and antibacterial applications. Recent studies have demonstrated that graphene quantum dots (GQDs) possess anti- and pro-oxidant properties simultaneously. However, their efficiency is low. Here, we report chlorine-doped GQDs (Cl-GQDs) with a tunable Cl doping amount and improved anti- and pro-oxidant activities. The scavenging performance and the free radical-produced efficiency of Cl-GQDs are about 7-fold and 3-fold, respectively, higher than those of the undoped GQDs. Meanwhile, Cl-GQDs are considered to be promising for antibacterial applications because of their enhanced singlet oxygen generating ability. We hope that this study could provide a new strategy to develop nanomaterials for application in the anti- and pro-oxidant field.

Comprehensive transcriptomic view of the role of the LGALS12 gene in porcine subcutaneous and intramuscular adipocytes

Background

Livestock production aims to provide meats of high and consistent eating quality. Insufficient intramuscular (IM) fat and excessive subcutaneous (SC) fat are paramount pork quality challenges. IM fat and SC fat, which are modulated by the adipogenesis of IM and SC adipocytes, play key roles in pork quality. Galectin-12 (LGALS12) was proven to be an important regulator of fat deposition in porcine. However, the current knowledge of the transcriptome-wide role of LGALS12 in adipocytes is still limited. This study was aimed to discover the different regulatory mechanisms of LGALS12 in porcine IM and SC adipocyte.

Results

The siRNA-mediated knockdown of the expression of LGALS12 identified 1075 and 3016 differentially expressed genes (DEGs) in IM and SC adipocytes, respectively. Among these, 585 were up- and 490 were downregulated in the IM adipocytes, while 2186 were up- and 830 were downregulated in the SC adipocytes. Moreover, 418 DGEs were observed only in the IM adipocytes, 2359 DGEs only in the SC adipocytes, and 657 DGEs in both types of adipocytes. According to Gene Ontology (GO) analysis, DEGs in both IM and SC adipocytes were mainly enriched in categories related to lipids or fat cell differentiation. Pathway analysis of the DEGs revealed 88 changed signaling pathways in the IM adipocytes and 86 in the SC adipocytes. The signaling pathways present in only one type of adipocyte were identified from among the top 50 signaling pathways in each type of adipocyte. Four signaling pathways, encompassing PI3K-AKT, cardiac muscle contraction, fatty acid metabolism and Ras, were significantly enriched in the IM adipocytes. On the other hand, four different signaling pathways, encompassing TNF, WNT, cGMP-PKG and NF-kappa B, were greatly enriched in the SC ones. The pathway changes were confirmed by chemical inhibition assays.

Conclusions

Our data reveals that LGALS12 knockdown alters the expression of numerous genes involved in key biological processes in the development of adipocytes. These observations provide a global view of the role of LGALS12 in porcine IM and SC adipocytes; thus, improving our understanding of the regulatory mechanisms by which this gene acts in fat development.

Electronic supplementary material

The online version of this article (10.1186/s12864-019-5891-y) contains supplementary material, which is available to authorized users.

Anisotropic Plasmonic Metal Heterostructures as Theranostic Nanosystems for Near Infrared Light-Activated Fluorescence Amplification and Phototherapy

The development of sophisticated theranostic systems for simultaneous near infrared (NIR) fluorescence imaging and phototherapy is of particular interest. Herein, anisotropic plasmonic metal heterostructures, Pt end-deposited Au nanorods (PEA NRs), are developed to efficiently produce hot electrons under 808 nm laser irradiation, exhibiting the strong electric density. These hot electrons can release the heat through electron-phonon relaxation and form reactive oxygen species through chemical transformation, as a result of potent photothermal and photodynamic performance. Simultaneously, the confined electromagnetic field of PEA NRs can transfer energy to adjacent polyethylene glycol (PEG)-linked NIR fluorophores (CF) based on their energy overlap mechanism, leading to remarkable NIR fluorescence amplification in CF-PEA NRs. Various PEG linkers (1, 3.4, 5.0, and 10 kD) are employed to regulate the distance between CF and PEA NRs of CF-PEA NRs, and the maximum fluorescence intensity is achieved in CF5k-PEA NRs. After further attachment with i-motif DNA/Nrf2 siRNA chimera to simultaneously suppress both cellular antioxidant defense and hyperthermia resistance effects, the final biocompatible CF5k-bPEA@siRNA NRs present promising NIR fluorescence imaging ability and 808 nm laser-activated photothermal and photodynamic therapeutic effect in MCF7 cells and tumor-bearing mice, holding great potential for cancer therapy.

Broadband Absorption Tailoring of SiO2/Cu/ITO Arrays Based on Hybrid Coupled Resonance Mode

Sub-wavelength artificial photonic structures can be introduced to tailor and modulate the spectrum of materials, thus expanding the optical applications of these materials. On the basis of SiO₂/Cu/ITO arrays, a hybrid coupled resonance (HCR) mechanism, including the epsilon-near-zero (ENZ) mode of ITO, local surface plasmon resonance (LSPR) mode and the microstructural gap resonance (GR) mode, was proposed and researched by systematically regulating the array period and layer thickness. The optical absorptions of the arrays were simulated under different conditions by the finite-difference time-domain (FDTD) method. ITO films were prepared and characterized to verify the existence of ENZ mode and Mie theory was used to describe the LSPR mode. The cross-sectional electric field distribution was analyzed while SiO₂/Cu/ITO multilayers were also fabricated, of which absorption was measured and calculated by Macleod simulation to prove the existence of GR and LSPR mode. Finally, the broad-band tailoring of optical absorption peaks from 673 nm to 1873 nm with the intensities from 1.8 to 0.41 was realized, which expands the applications of ITO-based plasmonic metamaterials in the near infrared (NIR) region.

Microsoft Concept Graph: Mining Semantic Concepts for Short Text Understanding

Knowlege is important for text-related applications. In this paper, we introduce Microsoft Concept Graph, a knowledge graph engine that provides concept tagging APIs to facilitate the understanding of human languages. Microsoft Concept Graph is built upon Probase, a universal probabilistic taxonomy consisting of instances and concepts mined from the Web. We start by introducing the construction of the knowledge graph through iterative semantic extraction and taxonomy construction procedures, which extract 2.7 million concepts from 1.68 billion Web pages. We then use conceptualization models to represent text in the concept space to empower text-related applications, such as topic search, query recommendation, Web table understanding and Ads relevance. Since the release in 2016, Microsoft Concept Graph has received more than 100,000 pageviews, 2 million API calls and 3,000 registered downloads from 50,000 visitors over 64 countries.

CRNDE enhances neuropathic pain via modulating miR-136/IL6R axis in CCI rat models

Neuropathic pain has been reported as a type of chronic pain due to the primary dysfunction of the somatosensory nervous system. It is the most serious types of chronic pain, which can lead to a significant public health burden. But, the understanding of the cellular and molecular pathogenesis of neuropathic pain is barely complete. Long noncoding RNAs (lncRNAs) have recently been regarded as modulators of neuronal functions. Growing studies have indicated lncRNAs can exert crucial roles in the development of neuropathic pain. Therefore, our present study focused on the potential role of the lncRNA Colorectal Neoplasia Differentially Expressed (CRNDE) in neuropathic pain progression. Firstly, a chronic constrictive injury (CCI) rat model was built. CRNDE was obviously increased in CCI rats. Interestingly, overexpression of CRNDE enhanced neuropathic pain behaviors. Neuroinflammation was induced by CRNDE and as demonstrated, interleukin-10 (IL-10), IL-1, IL-6, and tumor necrosis factor-α (TNF-α) protein levels in CCI rats were activated by LV-CRNDE. For another, miR-136 was obviously reduced in CCI rats. Previously, it is indicated that miR-136 participates in the spinal cord injury via an inflammation in a rat model. Here, firstly, we verified miR-136 could serve as CRNDE target. Loss of miR-136 triggered neuropathic pain remarkably via the neuroinflammation activation. Additionally, IL6R was indicated as a target of miR-136 and miR-136 regulated its expression. Subsequently, we confirmed that CRNDE could induce interleukin 6 receptor (IL6R) expression positively. Overall, it was implied that CRNDE promoted neuropathic pain progression via modulating miR-136/IL6R axis in CCI rat models.

High concentration of plasma cell free DNA alerted progressive and recurrent disease in children with high risk neuroblastoma

e21506

Background: Neuroblastoma (NB) happens most frequently among babies and it is also the third-most common cancer in children after leukemia and brain tumor. The unexpected occurrence of NB progression and relapse accounts for the low survival free event rates, therefore finding an effective biomarker to predict the progressive and recurrent events is urgent. Methods: A total of 116 NB patients with high risk (HR-NB) from Beijing Children’s Hospital between February 1, 2015 and December 31, 2017 were recruited. All patients received the regular multiple-disciplinary treatments and then followed the evaluation for therapeutic response according to the standards of Response Evaluation Criteria in Solid Tumors (RECIST). Blood samples were collected to quantify cell-free DNA levels at important time points including one week before or the beginning of maintenance stage, every or every three month after the beginning of maintenance stage, diagnosis of progression and recurrence. Results: Results showed that 36 HR-NB patients developed progressive disease (PD) and recurrent disease. More intriguingly, cfDNA concentration was extremely higher in NB patients with progression and recurrence than those with events free (29.34 ng/ml VS 10.32 ng/ml), and increasing cfDNA levels happened at least 0.55 months before the progression and recurrence was confirmed. By analyzing the area under the receiver operator characteristic (ROC) curve (AUC), it showed that the area of cfDNA level was 0.67 at 12.93 ng/ml with 62.5% sensitivity and 71.3% specificity. Conclusions: Taken together, it was suggested increasing cfDNA concentration in plasma may benefit to warn the incurrence of progression and recurrence in NB patients in clinic, which will help clinicians win much more valuable time to save patients’ lives.

Bioinspired Oxidation of Methane in the Confined Spaces of Molecular Cages

Non-heme iron, vanadium, and copper complexes bearing hemicryptophane cavities were evaluated in the oxidation of methane in water by hydrogen peroxide. According to ¹H nuclear magnetic resonance studies, a hydrophobic hemicryptophane cage accommodates a methane molecule in the proximity of the oxidizing site, leading to an improvement in the efficiency and selectivity for CH₃OH and CH₃OOH compared to those of the analogous complexes devoid of a hemicryptophane cage. While copper complexes showed low catalytic efficiency, their vanadium and iron counterparts exhibited higher turnover numbers, ≤13.2 and ≤9.2, respectively, providing target primary oxidation products (CH₃OH and CH₃OOH) as well as over-oxidation products (HCHO and HCOOH). In the case of caged vanadium complexes, the confinement effect was found to improve either the selectivity for CH₃OH and CH₃OOH (≤15%) or the catalytic efficiency. The confined space of the hydrophobic pocket of iron-based supramolecular complexes plays a significant role in the improvement of both the selectivity (≤27% for CH₃OH and CH₃OOH) and the turnover number of methane oxidation. These results indicate that the supramolecular approach is a promising strategy for the development of efficient and selective bioinspired catalysts for the mild oxidation of methane to methanol.

Photo-responsive liposomes composed of spiropyran-containing triazole-phosphatidylcholine: investigation of merocyanine-stacking effects on liposome-fiber assembly-transition

A spiropyran-containing triazole-phosphatidylcholine (SPTPC) was synthesized through a copper-catalyzed azide alkyne cyclo-addition (CuAAC) reaction. In water, SPTPCs self-assembled and a spontaneous spiropyran-to-merocyanine (SP-to-MC) isomerization occurred, resulting in coexistence of liposomes and fibers, and switching from the spiropyran (SP) to the merocyanine (MC) isomeric structure induced a reversible transition between these molecular assemblies. Study of the self-assembly of SPTPCs and photo-induced liposome-fiber assembly-transition revealed that the presence of MC enabled additional inter-membrane interaction during self-assembly and that the MC-stacking effect was the driving force for the assembly-transition. Exposure to UV light induced switching from SP to MC, where the planar structure of MC and the confinement of MC led to enhanced MC-stacking. The effect of MC-stacking was both advantageous and disadvantageous: MC-stacking perturbed the hydrophobic phase in the bilayer membrane and facilitated the liposome-to-fiber transition, otherwise the MC-stacking retarded switching of MC to SP, and caused an incomplete recovery of MC to SP during fiber-to-liposome recovery, thus a fatigue of SP was induced by MC-stacking during the liposome-to-fiber transition cycle. To decrease the intermolecular interactions and suppress MC-stacking, photo-inert triazole-phosphatidylcholine (TPC) was incorporated to prepare two-component TPC/SPTPC-liposomes, which exhibited better recovery kinetics. The photo-adaptive behavior of TPC/SPTPC-liposomes confirmed the disturbance of bilayer membranes by inter-membrane MC-stacking and the formation of MCTPC-enriched phases in the bilayer membrane.

[Research progress of maternal immunization]

Maternal immunization is an immune strategy that protects both mothers and early-life infants from disease by the vaccination of pregnant women. The effect of maternal immunization is influenced by the types of vaccines, the timing of vaccination, the subtypes of antibodies induced by vaccines, and the health status of mothers themselves. Inactivated influenza vaccination during pregnancy and DPT vaccination during the third trimester of pregnancy have been widely used in the world, while Hepatitis B vaccine, pneumococcal and meningococcal vaccines also show good efficacy and safety in pregnant women. This article reviews the research progress of Maternal Immunization in order to provide a reference for Maternal Immunization planning and policymaking in China.

MiRNA-199a-5p positively regulated RANKL-induced osteoclast differentiation by target Mafb protein

MicroRNAs are involved in osteoclast differentiation. Although miR-199a-5p plays an important role in many different systems and diseases, its function during osteoclastogenesis remains unclear. In this study, we investigated the function and the target gene of miR-199a-5p in osteoclast differentiation. The in vitro data showed that miR-199a-5p was significantly upregulated after the stimulation by receptor activator of nuclear factor kappa-B ligand in macrophages and RAW 264.7 cells. After transfection of miR-199a-5p mimic, the messenger RNA expression level of nuclear factor of activated T-cells cytoplasmic 1, tartrate-resistant acid phosphatase (TRAP), and receptor activator of nuclear factor kappa-B was significantly increased in RAW 264.7 cells and the number of TRAP-positive cells was also increased. MiR-199a-5p inhibitor showed the complete opposite outcome which brought additional proof to our finding. Overexpression of miR-199a-5p led to downregulation of Mafb protein. The luciferase activity was obviously repressed when WT-pGL3-Mafb and miR-199a-5p mimics were cotransfected into 293 T cells and the inhibitors cotransfected demonstrated reverse result. MiR-199a-5p overexpressed during osteoclast differentiation and positively regulated osteoclast formation in vitro by target Mafb.

Supervision Strategies and Their Correlates: An Empirical Study of Chinese Community Correctional Staff

While there are different approaches to dealing with offenders sentenced to community corrections, the three major ones are law enforcement (surveillance), therapeutic (rehabilitation), and crime opportunity prevention. Using the study of U.S. community corrections staff by Miller as a guide, the current study examined the supervision strategy used by Chinese community corrections staff in the Hubei province of China. Chinese community corrections staff were more likely to use the therapeutic and crime opportunity prevention approaches than the law enforcement model. Predictors of each of the three offender supervision approaches differed. The results from Chinese staff were similar in many ways to that found among U.S. staff reported by Miller but differed in some areas.

Effect of Dissolved Oxygen Concentration on the Microbiologically Influenced Corrosion of Q235 Carbon Steel by Halophilic Archaeon Natronorubrum tibetense

The influence of dissolved oxygen concentration (DOC) on the microbiologically influenced corrosion (MIC) of Q235 carbon steel in the culture medium of halophilic archaeon Natronorubrum tibetense was investigated. The increase of DOC from 0.0 to 3.0 ppm was found to strengthen the oxygen concentration cell by promoting cathodic reaction. Meanwhile, the increased DOC also promoted archaeal cell growth, which could consume more metallic iron as energy source and aggravated the localized corrosion. When the DOC further increased to 5.0 ppm, the uniform corrosion was dominant as the biofilms became uniformly presented on the steel surface. Combined with the stronger inhibition effect of oxygen diffusion by the increased biofilm coverage, the MIC of carbon steel in the 5.0 ppm medium was weaker than that in the 3.0 ppm medium. From weight loss and electrochemical tests, the results all demonstrated that the carbon steel in the 3.0 ppm medium had the largest corrosion rate.

Environmental Risk Factors and Geographic Distribution of Severe Fever with Thrombocytopenia Syndrome in Jiangsu Province, China

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging natural focus, tick-borne disease caused by a novel bunyavirus named SFTS virus (SFTSV). The main purpose of this study was to analyze the environmental risk factors and geographic distribution of SFTS natural foci in Jiangsu Province. A retrospective space-time analysis by SaTScan software was used to detect clusters at the town level. The maximum entropy modeling method was applied to construct the ecological niche model and analyze the environmental risk factors, and then to draw the predicted risk map. The performance of the model was assessed using the area under the curve (AUC) and known occurrence locations. During the years 2010-2016, a total of 140 laboratory-confirmed indigenous SFTS cases occurred in Jiangsu Province, with 66 occurrence locations. The reported number of SFTS cases increased year by year and SFTS cases occurred from April to October with a peak between May and August each year. Three clusters detected by space-time scan statistical analysis were connected together and shared the similar ecological environmental characteristic of hilly landscape. Fifteen environmental variables with different percent contribution can influence the ecological niche model in different degrees, whereas slope (suitable range: 0.1-4) and maximum temperature of warmest month (suitable range: 32.8-34.2°C) as the key environmental factors contributed 46.1% and 23.2%, respectively. The model had high accuracy on prediction with the averaged training AUC of 0.926. Within a predicted risk map, potential areas at high risk and 10 previously unidentified endemic regions were recognized. The distribution of SFTS natural foci was under the influence of multidimensional environmental factors. Slope and maximum temperature of warmest month were the key environmental risk factors. These results provide a valuable basis for the selection of prevention and control strategies, and the identification of potential risk areas.

Identification and characterization of a polysaccharide from the roots of Morinda officinalis, as an inducer of bone formation by up-regulation of target gene expression

Morinda officinalis is an important traditional tonic herbal medicine. In the present study, we found that crude polysaccharides extracted from M. officinalis, named MO90, could significantly increase the bone mineral density (BMD) of the whole femur, distal femur, and proximal femur in ovariectomized (OVX) rats. In addition, MO90 decreased the level of bone turnover markers and prevented the deterioration of trabecular microarchitecture. To investigate the fractions responsible for anti-osteoporosis activity, one novel inulin-type fructan, MOW90-1, was isolated from MOP90. Structural analysis indicated that MOW90-1 consists of a backbone of (2→1)-linked-β-D-Fruf, and is terminated with (1→)-linked-α-D-Glcp and (2→)-linked-β-D-Fruf. Furthermore, an in vitro anti-osteoporosis assay indicated that MOW90-1 promoted proliferation, differentiation, and mineralization of MC3T3-E1 cells by up-regulating the expression of runt-related transcription factor 2, osterix, osteopontin, and osteocalcin. In conclusion, our studies provide supporting evidence for future use of this novel M. officinalis fructan as a key nutrient of health products.

Evolution of E. coli Phytase for Increased Thermostability Guided by Rational Parameters

Phytases are enzymes that can hydrolyze phytate and its salts into inositol and phosphoric acid, and have been utilized to increase the availability of nutrients in animal feed and mitigate environmental pollution. However, the enzymes’low thermostability has limited their application during the feed palletization process. In this study, a combination of B-value calculation and protein surface engineering was applied to rationally evolve the heat stability of Escherichia coli phytase. After systematic alignment and mining for homologs of the original phytase from the histidine acid phosphatase family, the two models 1DKL and 1DKQ were chosen and used to identify the B-values and spatial distribution of key amino acid residues. Consequently, thirteen potential amino acid mutation sites were obtained and categorized into six domains to construct mutant libraries. After five rounds of iterative mutation screening, the thermophilic phytase mutant P56214 was finally yielded. Compared with the wild-type, the residual enzyme activity of the mutant increased from 20% to 75% after incubation at 90°C for 5 min. Compared with traditional methods, the rational engineering approach used in this study reduces the screening workload and provides a reference for future applications of phytases as green catalysts.

Regulation of anthocyanin accumulation via MYB75/HAT1/TPL-mediated transcriptional repression

Anthocyanin is part of secondary metabolites, which is induced by environmental stimuli and developmental signals, such as high light and sucrose. Anthocyanin accumulation is activated by the MYB-bHLH-WD40 (MBW) protein complex in plants. But the evidence of how plants maintain anthocyanin in response to signals is lacking. Here we perform molecular and genetic evidence to display that HAT1 plays a new breaker of anthocyanin accumulation via post-translational regulations of MBW protein complex. Loss of function of HAT1 in the Arabidopsis seedlings exhibits increased anthocyanin accumulation, whereas overexpression of HAT1 significantly repressed anthocyanin accumulation. We found that HAT1 interacted with MYB75 and thereby interfered with MBW protein complex. Overexpression of HAT1 suppresses abundant anthocyanin phenotype of pap1-D plant. HAT1 is characterized as a transcriptional repressor possessing an N-terminal EAR motif, which determines to interact with TOPLESS corepressor. Repression activity of HAT1 in regulation of gene expression and anthocyanin accumulation can be abolished by deletion or mutation of the EAR motif 1. Chromatin immunoprecipitation assays revealed that MYB75 formed a transcriptional repressor complex with HAT1-TPL by histone H3 deacetylation in target genes. We proposed that HAT1 restrained anthocyanin accumulation by inhibiting the activities of MBW protein complex through blocking the formation of MBW protein complex and recruiting the TPL corepressor to epigenetically modulate the anthocyanin late biosynthetic genes (LBGs).

Anthocyanins, a class of flavonoids distributed ubiquitously in the plant kingdom, are induced by environmental stimuli and developmental signals, such as high light and sucrose. It is well established that anthocyanin accumulation is regulated by the MYB-bHLH-WD40 (MBW) protein complex in plants. But little is known about the regulation of MBW protein complex by other factors. Here, we show that an HD-ZIP II transcription factor HAT1 negatively regulates anthocyanin accumulation via post-translational regulation of MBW protein complex. Loss of function of HAT1 in the Arabidopsis seedlings exhibits increased anthocyanin accumulation, whereas overexpression of HAT1 significantly repressed anthocyanin accumulation. We reveal that HAT1 interacted with MYB75 and thereby sequestered MBW protein complex. Overexpression of HAT1 in pap1-D mutant suppresses abundant anthocyanin phenotype of the pap1-D mutant. HAT1 identified was as a transcriptional repressor possessing an N-terminal EAR motif, which determines the interaction with TOPLESS corepressor. The deletion or mutation of the EAR motif 1 of HAT1 partially eliminates the repression activity of HAT1 in regulation of gene expression and anthocyanin accumulation. Our results illustrate a new repressor HAT1 which helps plants fine-tune anthocyanin accumulation.