Engineering Shewanella oneidensis enables xylose-fed microbial fuel cell

BACKGROUND

The microbial fuel cell (MFC) is a green and sustainable technology for electricity energy harvest from biomass, in which exoelectrogens use metabolism and extracellular electron transfer pathways for the conversion of chemical energy into electricity. However, Shewanella oneidensis MR-1, one of the most well-known exoelectrogens, could not use xylose (a key pentose derived from hydrolysis of lignocellulosic biomass) for cell growth and power generation, which limited greatly its practical applications.

RESULTS

Herein, to enable S. oneidensis to directly utilize xylose as the sole carbon source for bioelectricity production in MFCs, we used synthetic biology strategies to successfully construct four genetically engineered S. oneidensis (namely XE, GE, XS, and GS) by assembling one of the xylose transporters (from Candida intermedia and Clostridium acetobutylicum) with one of intracellular xylose metabolic pathways (the isomerase pathway from Escherichia coli and the oxidoreductase pathway from Scheffersomyces stipites), respectively. We found that among these engineered S. oneidensis strains, the strain GS (i.e. harbouring Gxf1 gene encoding the xylose facilitator from C. intermedi, and XYL1, XYL2, and XKS1 genes encoding the xylose oxidoreductase pathway from S. stipites) was able to generate the highest power density, enabling a maximum electricity power density of 2.1 ± 0.1 mW/m².

CONCLUSION

To the best of our knowledge, this was the first report on the rationally designed Shewanella that could use xylose as the sole carbon source and electron donor to produce electricity. The synthetic biology strategies developed in this study could be further extended to rationally engineer other exoelectrogens for lignocellulosic biomass utilization to generate electricity power.

Study of the estrogenic-like mechanism of glycosides of cistanche using metabolomics

Cistanche deserticola, known as Rou Cong-Rong in China, has been used as a tonic for more than 1800 years, with previous studies demonstrating that glycosides of cistanche (GCs) are a main active component.

Prospective validation of a novel renal activity index of lupus nephritis

Objectives The renal activity index for lupus (RAIL) score was developed in children with lupus nephritis as a weighted sum of six urine biomarkers (UBMs) (neutrophil gelatinase-associated lipocalin, monocyte chemotactic protein 1, ceruloplasmin, adiponectin, hemopexin and kidney injury molecule 1) measured in a random urine sample. We aimed at prospectively validating the RAIL in adults with lupus nephritis. Methods Urine from 79 adults was collected at the time of kidney biopsy to assay the RAIL UBMs. Using receiver operating characteristic curve analysis, we evaluated the accuracy of the RAIL to discriminate high lupus nephritis activity status (National Institutes of Health activity index (NIH-AI) score >10), from low/moderate lupus nephritis activity status (NIH-AI score ≤10). Results In this mixed racial cohort, high lupus nephritis activity was present in 15 patients (19%), and 71% had proliferative lupus nephritis. Use of the identical RAIL algorithm developed in children resulted in only fair prediction of lupus nephritis activity status of adults (area under the receiver operating characteristic curve (AUC) 0.62). Alternative weightings of the six RAIL UBMs as suggested by logistic regression yielded excellent accuracy to predict lupus nephritis activity status (AUC 0.88). Accuracy of the model did not improve with adjustment of the UBMs for urine creatinine or albumin, and was little influenced by concurrent kidney damage. Conclusions The RAIL UBMs provide excellent prediction of lupus nephritis activity in adults. Age adaption of the RAIL is warranted to optimize its discriminative validity to predict high lupus nephritis activity status non-invasively.

Crystal clear: visualizing the intervention mechanism of the PD-1/PD-L1 interaction by two cancer therapeutic monoclonal antibodies

Antibody-based PD-1/PD-L1 blockade therapies have taken center stage in immunotherapies for cancer, with multiple clinical successes. PD-1 signaling plays pivotal roles in tumor-driven T-cell dysfunction. In contrast to prior approaches to generate or boost tumor-specific T-cell responses, antibody-based PD-1/PD-L1 blockade targets tumor-induced T-cell defects and restores pre-existing T-cell function to modulate antitumor immunity. In this review, the fundamental knowledge on the expression regulations and inhibitory functions of PD-1 and the present understanding of antibody-based PD-1/PD-L1 blockade therapies are briefly summarized. We then focus on the recent breakthrough work concerning the structural basis of the PD-1/PD-Ls interaction and how therapeutic antibodies, pembrolizumab targeting PD-1 and avelumab targeting PD-L1, compete with the binding of PD-1/PD-L1 to interrupt the PD-1/PD-L1 interaction. We believe that this structural information will benefit the design and improvement of therapeutic antibodies targeting PD-1 signaling.

Inhibitory effects of tributyl phosphate on algal growth, photosynthesis, and fatty acid synthesis in the marine diatom Phaeodactylum tricornutum

The widely used solvent extractant, tributyl phosphate (TBP), primarily used as a solvent for the conventional processing of nuclear fuel, has come under scrutiny recently due to concerns surrounding potential environmental contamination and toxicity. In this study, we found that, in Phaeodactylum tricornutum, administration of TBP severely inhibited algal cell growth by reducing photosynthetic efficiency and inducing oxidative stress. We further explored the effect of TBP by examining the gene expression of the photosynthetic electron transport chain and its contribution to reactive oxygen species (ROS) burst. Our data revealed that TBP affected both fatty acid content and profile by regulating the transcription of genes related to glycolysis, fatty acid biosynthesis, and β-oxidation. These results demonstrated that TBP did in fact trigger the synthesis of ROS, disrupting the subcellular membrane structure of this aquatic organism. Our study brings new insight into the fundamental mechanism of toxicity exerted by TBP on the marine alga P. tricornutum.

NLS‑RARα modulates acute promyelocytic leukemia NB4 cell proliferation and differentiation via the PI3K/AKT pathway

In patients with acute promyelocytic leukemia (APL), ~98% express the promyelocytic leukemia (PML)‑retinoic acid receptor α (RARα) fusion protein. Previous studies have shown that, in primary leukemia cells of patients with APL, the cleavage of PML‑RARα by neutrophil elastase is important for its ability to initiate APL. This cleavage separates the nuclear localization signal (NLS) from PML, leading to the formation of a novel protein, NLS‑RARα, although its underlying mechanism in APL remains to be fully elucidated. In the present study, the role of NLS‑RARα on the proliferation and differentiation of APL NB4 cells was investigated. Lentiviral vectors were constructed and transfected NLS‑RARα in NB4 cells, puromycin was used to select the stable transfected cell lines. Cell Counting Kit‑8 and flow cytometry analysis revealed that the efficient overexpression of NLS‑RARα significantly promoted NB4 cell proliferation and inhibited all‑trans retinoic acid‑induced cell differentiation. Furthermore, the NLS‑RARα protein promoted a significant increase in AKT and glycogen synthase kinase 3β (GSK‑3β) phosphorylation. The protein levels of phosphorylated (p) AKT and pGSK‑3β were decreased following pretreatment with the phosphatidylinositol 3‑kinase (PI3K) inhibitor, LY294002. These findings suggested that NLS‑RARα was an important molecule associated with the occurrence of APL via the PI3K‑AKT signaling pathway, and indicated that the NLS‑RARα protein may be a novel target for the treatment of APL.

Numerical method to compute acoustic scattering effect of a moving source

In this paper, the aerodynamic characteristic of a ducted tail rotor in hover has been numerically studied using CFD method. An analytical time domain formulation based on Ffowcs Williams–Hawkings (FW–H) equation is derived for the prediction of the acoustic velocity field and used as Neumann boundary condition on a rigid scattering surface. In order to predict the aerodynamic noise, a hybrid method combing computational aeroacoustics with an acoustic thin-body boundary element method has been proposed. The aerodynamic results and the calculated sound pressure levels (SPLs) are compared with the known method for validation. Simulation results show that the duct can change the value of SPLs and the sound directivity. Compared with the isolate tail rotor, the SPLs of the ducted tail rotor are smaller at certain azimuth.

Asymmetric Michael Addition Induced by (R)-tert-Butanesulfinamide and Syntheses of Chiral Pyrazolidinone Derivatives

A highly diastereoselective Michael addition of (R)-N-tert-butanesulfinyl imidates 8 to α,β-unsaturated pyrazolidinone 3a has been developed to afford pyrazolidinones 10 possessing three contiguous stereocenters with good to excellent yield and excellent diastereoselectivity. A two-step conversion of reduction and cyclization provides the bicyclic pyrazolopiperidine 12 in a good yield. A series of pyrazolopiperidine derivatives 18 with a quaternary carbon center at C-3a are stereoselectively synthesized via alkylation or Michael addition.

The Predictive Validity of the National Board of Osteopathic Medical Examiners' COMLEX-USA Examinations With Regard to Outcomes on American Board of Family Medicine Examinations

PURPOSE

To examine the predictive validity of the National Board of Osteopathic Medical Examiners' Comprehensive Osteopathic Medical Licensing Examination of the United States of America (COMLEX-USA) series with regard to the American Board of Family Medicine's (ABFM's) In-Training Examination (ITE) and Maintenance of Certification for Family Physicians (MC-FP) Examination.

METHOD

A repeated-measures design was employed, using test scores across seven levels of training for 1,023 DOs who took the MC-FP for the first time between April 2012 and November 2014 and for whom the ABFM had ITE scores for each of their residency years. Pearson and disattenuated correlations were calculated; Fisher r to z transformation was performed; and sensitivity, specificity, and positive and negative predictive values for the COMLEX-USA Level 2-Cognitive Evaluation (CE) with regard to the MC-FP were computed.

RESULTS

The Pearson and disattenuated correlations ranged from 0.55 to 0.69 and from 0.61 to 0.80, respectively. For MC-FP scores, only the correlation increase from the COMLEX-USA Level 2-CE to Level 3 was statistically significant (for Pearson correlations: z = 2.41, P = .008; for disattenuated correlations: z = 3.16, P < .001). The sensitivity, specificity, and positive and negative predictive values of the COMLEX-USA Level 2-CE with the MC-FP were 0.90, 0.39, 0.96, and 0.19, respectively.

CONCLUSIONS

Evidence was found that the COMLEX-USA can assist family medicine residency program directors in predicting later resident performance on the ABFM's ITE and MC-FP, which is becoming increasingly important as graduate medical education accreditation moves toward a single aligned model.

Hollow mesoporous carbon nanocarriers for vancomycin delivery: understanding the structure-release relationship for prolonged antibacterial performance

Mono-dispersed mesoporous hollow carbon (MHC) nanospheres with comparable structures have been designed as nanocarriers for the delivery of vancomycin (Van) to inhibit bacterial growth. It is demonstrated that MHC materials possess a Van loading capacity of 861 mg g^-1, much higher than that of any Van nanocarrier in previous reports. By comparing the drug loading, release and antibacterial performance of MHC nanospheres with controllable structures, it is shown that MHC with a pore size of 5.8 nm and a wall thickness of 25 nm exhibits compromising storage-release behaviour and achieves extended bactericidal activity of Van towards E. coli and S. epidermidis compared to free Van and other MHC nanocarriers. This study provides new knowledge about the rational design of carbon based nanocarriers to enhance the therapeutic efficacy of antibiotics.

The Influenza A Virus Non-structural Protein NS1 Upregulates The Expression of Collagen Triple Helix Repeat Containing 1 Protein

Influenza A virus (IAV) infection induces a strong immune response and regulates the expression of many host proteins. The collagen triple helix repeat containing 1 (CTHRC1) protein is a secreted protein that exhibits increased expression during the viral infection process. However, the regulatory function of IAV on CTHRC1 expression is obscure. In this study, we investigated the effect of IAV on CTHRC1 expression and its regulatory mechanism. A total of 106 serum specimens from healthy people and 80 serum specimens from patients infected with IAV were collected. The CTHRC1 levels in the sera from the IVA patients and healthy individuals were measured using an enzyme-linked immunosorbent assay (ELISA), and the differences were statistically analysed. A549 cells were infected with the IAV or delNS1 virus. Additionally, A549 cells were cotransfected with a eukaryotic non-structural NS1 protein gene expression plasmid and the CTHRC1 gene promoter reporter plasmid (pCTHRC1-Luc), and, the luciferase activities were assessed. The CTHRC1 mRNA and protein expression were detected using reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting, respectively. The serum CTHRC1 level was significantly higher in the IAV patients than in the healthy individuals. IAV upregulated the CTHRC1 mRNA and protein expression. The non-structural NS1 protein specifically activated CTHRC1 gene promoter activity and upregulated CTHRC1 mRNA and protein expression. The activation function had a dose-dependent effect, indicating that influenza virus upregulated CTHRC1 expression through its NS1 protein.

A Vesicle Supra-Assembly Approach to Synthesize Amine-Functionalized Hollow Dendritic Mesoporous Silica Nanospheres for Protein Delivery

Intracellular delivery of proteins is a promising strategy of intervention in disease, which relies heavily on the development of efficient delivery platforms due to the cell membrane impermeability of native proteins, particularly for negatively charged large proteins. This work reports a vesicle supra-assembly approach to synthesize novel amine-functionalized hollow dendritic mesoporous silica nanospheres (A-HDMSN). An amine silica source is introduced into a water-oil reaction solution prior to the addition of conventional silica source tetraethylorthosilicate. This strategy favors the formation of composite vesicles as the building blocks which further assemble into the final product. The obtained A-HDMSN have a cavity core of ≈170 nm, large dendritic mesopores of 20.7 nm in the shell and high pore volume of 2.67 cm³ g^-1 . Compared to the calcined counterpart without amine groups (C-HDMSN), A-HDMSN possess enhanced loading capacity to large negative proteins (IgG and β-galactosidase) and improved cellular uptake performance, contributed by the cationic groups. A-HDMSN enhance the intracellular uptake of β-galactosidase by up to 5-fold and 40-fold compared to C-HDMSN and free β-galactosidase, respectively. The active form of β-galactosidase delivered by A-HDMSN retains its intracellular catalytic functions.

Mesoporous Magnesium Oxide Hollow Spheres as Superior Arsenite Adsorbent: Synthesis and Adsorption Behavior

Arsenic contamination in natural water has posed a significant threat to global health due to its toxicity and carcinogenity. Adsorption technology is an easy and flexible method for arsenic removal with high efficiency. In this Article, we demonstrated the synthesis of mesoporous MgO hollow spheres (MgO-HS) and their application as high performance arsenite (As(III)) adsorbent. MgO-HS with uniform particle size (∼180 nm), high specific surface area (175 m(2) g(-1)), and distinguished mesopores (9.5 nm in size) have been prepared by hard-templating approach using mesoporous hollow carbon spheres as templates. An ultrahigh maximum As(III) adsorption capacity (Qmax) of 892 mg g(-1) was achieved in batch As(III) removal study. Adsorption kinetic study demonstrated that MgO-HS could enable As(III) adsorption 6 times faster as a commercial MgO adsorbent. The ultrahigh adsorption capacity and faster adsorption kinetics were attributed to the unique structure and morphology of MgO-HS that enabled fast transformation into a flower-like porous structure composed of ultrathin Mg(OH)2 nanosheets. This in situ formed structure provided abundant and highly accessible hydroxyl groups, which enhanced the adsorption performance toward As(III). The outstanding As(III) removal capability of MgO-HS showed their great promise as highly efficient adsorbents for As(III) sequestration from contaminated water.

Design and construction of synthetic microbial consortia in China

The rapid development of synthetic biology enables the design, construction and optimization of synthetic microbial consortia to achieve specific functions. In China, the "973" project-"Design and Construction of Microbial Consortia" was funded by the National Basic Research Program of China in January 2014. It was proposed to address the fundamental challenges in engineering natural microbial consortia and reconstructing microbial consortia to meet industrial demands. In this review, we will introduce this "973" project, including the significance of microbial consortia, the fundamental scientific issues, the recent research progresses, and some case studies about synthetic microbial consortia in the past two and a half years.