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.

Crosstalk between cytokinin and ethylene signaling pathways regulates leaf abscission in cotton in response to chemical defoliants

Abscission is a process that allows plants to shed tissues or organs via cell separation, and occurs throughout the life cycle. Removal of leaves through the use of chemical defoliants is very important for mechanical harvesting of cotton (Gossypium hirsutum). However, our knowledge of the molecular mechanisms of the defoliation response involved is limited. In this study, RNA-seq was conducted in order to profile the differentially expressed genes (DEGs) between cultivars X50 (sensitive to chemical defoliants) and X33 (relatively insensitive) at different time points after treatment with thidiazuron and ethephon (TE). A total of 2434 DEGs were identified between the two cultivars across the different time-points. Functional categories according to GO and KEGG analyses revealed that plant hormone signal transduction and zeatin biosynthesis were involved in the response to TE. Cytokinin oxidase/dehydrogenase (CKX) genes and ethylene-related genes were up-regulated following TE treatment, and were associated with increased level of ethylene, especially in cultivar X50. Down-regulation of GhCKX3 resulted in delayed defoliation and a reduced ethylene response. The results show that crosstalk between cytokinin and ethylene regulates cotton defoliation, and provide new insights into the molecular mechanisms underlying the mode of action of defoliants in cotton.

Oxygen-Vacancy Dynamics and Entanglement with Polaron Hopping at the Reduced CeO_{2}(111) Surface

The migration of oxygen vacancies (V_{O}) in ceria-based systems is crucial to their functionality in applications. Yet, although the V_{O}'s structure and the distribution of the Ce^{3+} polarons at the CeO_{2}(111) surface has received extensive attention, the dynamic behaviors of V_{O}'s and polarons are not fully understood. By combining density functional theory calculations and ab initio molecular dynamics simulations, we show that the movements of V_{O}'s and polarons exhibit very distinct entanglement characteristics within a temperature range of 300-900 K, and that the positions of the Ce^{3+} polarons play a key role in the V_{O} migration. Long-distance vacancy migration occurs at moderate temperatures when the "suitable" Ce^{3+} distribution remains long enough to promote oxygen migration. This study provides microscopic insight into the interplay between the electronic and ionic charge transport in ceria that will be beneficial for the rational design of conductive ceria-based materials.

Cross-coupling drift between magnetic field and temperature in depolarized interferometric fiber optic gyroscope

We propose a theory of cross-coupling drift in depolarized interferometric fiber optic gyroscopes (D-IFOGs) under the joint influence of magnetic field and temperature. The magnetic field and temperature cross-coupling drift (MTCD) originates from the interaction of the nonreciprocal circular birefringence produced by the magnetic field, the thermal stress birefringence from the varying temperature, and the inherent residual birefringence in the fiber coil. The MTCD is much greater than the sum of the individual drifts induced by magnetic field and temperature. We established a relevant theoretical model and carried out numerical simulations, and verified the results experimentally. For a typical D-IFOG, the experimental results showed a cross-coupling degree exceeding 170% when the temperature varied from -20 °C to 60 °C, as predicted in the simulations.

Selectively Potentiating Hypoxia Levels by Combretastatin A4 Nanomedicine: Toward Highly Enhanced Hypoxia-Activated Prodrug Tirapazamine Therapy for Metastatic Tumors

Hypoxia-activated prodrugs (HAPs) have the potential to selectively kill hypoxic cells and convert tumor hypoxia from a problem to a selective treatment advantage. However, HAPs are unsuccessful in most clinical trials owing to inadequate hypoxia within the treated tumors, as implied by a further substudy of a phase II clinical trial. Here, a novel strategy for the combination of HAPs plus vascular disrupting agent (VDA) nanomedicine for efficacious solid tumor therapy is developed. An effective VDA nanomedicine of poly(l-glutamic acid)-graft-methoxy poly(ethylene glycol)/combretastatin A4 (CA4-NPs) is prepared and can selectively enhance tumor hypoxia and boost a typical HAP tirapazamine (TPZ) therapy against metastatic 4T1 breast tumors. After treatment with the combination of TPZ plus CA4-NPs, complete tumor reduction is observed in 4T1 xenograft mice (initial tumor volume is 180 mm³ ), and significant tumor shrinkage and antimetastatic effects are observed in challenging large tumors with initial volume of 500 mm³ . The report here highlights the potential of using a combination of HAPs plus VDA nanomedicine in solid tumor therapy.

Improvement of anticorrosion ability of epoxy matrix in simulate marine environment by filled with superhydrophobic POSS-GO nanosheets

Super-hydrophobicity polyhedral oligomeric silsesquioxane-modified graphene oxide (POSS-GO) was synthesized by one-step reaction between graphene oxide (GO) and aminopropylisobutyl polyhedral oligomeric silsesquioxane (POSS-NH₂). Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) spectra indicated that the POSS were successfully connected to the edge and surface of GO nanosheets. Scanning probe microscope (SPM) and transmission electron microscope (TEM) images demonstrated that the POSS-GO with a thickness of 1.58 nm presented a stably dispersion in anhydrous ethanol. Results from electrochemical behaviors showed that the proper incorporation of POSS-GO could availably improve the anticorrosion ability of epoxy based coatings in simulate marine environment (3.5 wt% NaCl solution). The good dispersion of POSS-GO helped to fill the original defect and enhanced the complication of penetration path. The super-hydrophobicity of POSS-GO was beneficial to the reduction of actual contact zone. The synergistic effect of good dispersion and super-hydrophobicity promoted the enhancement of anticorrosion ability for composite coatings.

High-efficiency expression and secretion of human FGF21 in Bacillus subtilis by intercalation of a mini-cistron cassette and combinatorial optimization of cell regulatory components

Background

Recombinant human Fibroblast growth factor 21 (rhFGF21) is an endocrine hormone that has profound effects on treatment of metabolic diseases. However, rhFGF21 is prone to form inclusion body when expressed in bacteria, which results in, the downstream process of purification of bioactive rhFGF21 is time-consuming and labor intensive. The aim of this work is to explore a new method for improving the soluble expression and secretion level of rhFGF21 in B. subtilis.

Results

A codon optimized rhFGF21 gene was expressed under the control of a strong inducible promoter P_malA in B. subtilis. A mini-cistron cassette (from gsiB) was located upstream of rhFGF21 in expression vector (pMATEFc5), which could reduce the locally stabilized mRNA secondary structure of transcripts and enhance the efficiency of translation initiation. Then various chaperones were further overexpressed to improve the expression efficiency of rhFGF21. Results showed that overexpression of the chaperone DnaK contributed to the increase of solubility of rhFGF21. Moreover, an extracellular proteases deficient strain B. subtilis Kno6cf was used to accumulate the secreted rhFGF21 solidly. In addition, eleven signal peptides from B. subtilis were evaluated and the SP_dacB appeared the highest secretion yield of rhFGF21 in B. subtilis. Finally, the combinatorial optimized strain achieved an about ninefold increase of the soluble rhFGF21 production after 24 h of flask fermentation in comparison with the initial production strain.

Conclusion

This work provided a comprehensive strategy for secretory expressing the heterologous protein rhFGF21 in B. subtilis. To our knowledge, this is the first report of the highly efficient production of rhFGF21 in B. subtilis and this approach may provide some suggestions for heterologous proteins production in B. subtilis.

Electronic supplementary material

The online version of this article (10.1186/s12934-019-1066-4) contains supplementary material, which is available to authorized users.