Syntrophic Growth of Geobacter sulfurreducens Accelerates Anaerobic Denitrification

Nitrate is considered as a contamination since it’s over discharging to water incurs environmental problems. However, nitrate is an ideal electron sink for anaerobic pollutant degraders desiring electron acceptors due to the high redox potential. Unfortunately, not all degraders can directly reduce nitrate, and the anaerobic direct interspecies electron transfer (DIET) between degraders and denitrifiers has not been confirmed yet. Here we demonstrated that syntrophic growth of Geobacter sulfurreducens PCA with denitrifying microbial community at anaerobic condition eliminated the lag phase of 15 h and improved the denitrification rate by 13∼51% over a broad C/N ratio of 0.5 to 9. Quantitative PCR revealed that G. sulfurreducens selectively enhanced the expression of nirS coding for a cytochrome cd1-nitrite reductase, resulting in a fast and more complete denitrification. Geobacter also selectively enriched its potential denitrifying partners – Diaphorobacter, Delftia, and Shinella – to form spherical aggregates. More studies of the binary culture system need to be carried out to confirm the syntrophic mechanism of Geobacter and denitrifiers in the future. These findings extend our knowledge on understanding the anaerobic bacterial interspecies electron transfer in the denitrification process, which has broader implications in fast selection and stabilization of denitrifiers in wastewater treatment plant, and general understanding of ecology for nitrogen and metal cycling

A novel Fas ligand plays an important role in cell apoptosis of Crassostrea hongkongensis: molecular cloning, expression profiles and functional identification of ChFasL

BackgroundApoptosis regulates normal development, homeostasis, immune tolerance and response to environmental stress by eliminating unwanted or diseased cells, and plays a key role in non-specific immunity of invertebrates. The exogenous pathway mediated by death receptors and death ligands is a very important pathway for cell apoptosis. Death ligands are mainly members of the tumour necrosis factor (TNF) family, of which FasL is an important member. The deep involvement of FasL in vertebrates cell apoptosis and immunity has been reported many times, but there is limited research on the FasL gene in shellfish, and its functional importance in oyster cell apoptosis and immunity remains unclear.MethodsThe full length of ChFasL was identified and cloned based on the genome of Crassostrea hongkongensis. Quantitative PCR was used to detect the relative expression of ChFasL in different developmental stages and tissues, as well as the changes of relative expression in hemocytes after bacterial infection. The expression position of ChFasL in HEK293T cells was also located by subcellular localization, and the effect of increased recombinant protein content on the activity of reporter genes p53 and p21 was studied by dual-fluorescence reporter gene. Finally, the changes of apoptosis rate in hemocytes after ChFasL silencing was identified by RNA interference technology.ResultsWe identified a novel FasL gene from C. hongkongensis and named it ChFasL. We found that ChFasL has potential N-linked glycosylation site, a transmembrane domain and a TNF region, which was a typical characteristics of TNF family. ChFasL was expressed in all developmental stages of larvae and in all tissues of oysters. After stimulation by V. alginolyticus or S. haemolyticus, its relative expression in hemocytes increased significantly, suggesting that ChFasL was deeply engaged in the immune response process of C. hongkongensis to external microbial stimulation. The results of subcellular localization showed that ChFasL was mainly distributed in the cytoplasm of HEK293T cells. With the overexpression of the recombinant protein pcDNA3 1- ChFasL, the activity of p53 and p21 significantly increased, showing a positive regulatory effect. Moreover, after dsRNA successfully reduced the relative expression of ChFasL, the apoptosis rate of hemocytes was significantly lower than that the dsGFP group.ConclusionThese results comprehensively confirmed the important role of ChFasL in the apoptosis process of C. hongkongensis, which provided the basis and premise for the in-depth understanding of the immune function of apoptosis in molluscs, and also contributed to the research on the pathogenic death mechanism and disease resistance breeding of marine bivalves

A Marine Anthraquinone SZ-685C Overrides Adriamycin-Resistance in Breast Cancer Cells through Suppressing Akt Signaling

Breast cancer remains a major health problem worldwide. While chemotherapy represents an important therapeutic modality against breast cancer, limitations in the clinical use of chemotherapy remain formidable because of chemoresistance. The HER2/PI-3K/Akt pathway has been demonstrated to play a causal role in conferring a broad chemoresistance in breast cancer cells and thus justified to be a target for enhancing the effects of anti-breast cancer chemotherapies, such as adriamycin (ADR). Agents that can either enhance the effects of chemotherapeutics or overcome chemoresistance are urgently needed for the treatment of breast cancer. In this context, SZ-685C, an agent that has been previously shown, as such, to suppress Akt signaling, is expected to increase the efficacy of chemotherapy. Our current study investigated whether SZ-685C can override chemoresistance through inhibiting Akt signaling in human breast cancer cells. ADR-resistant cells derived from human breast cancer cell lines MCF-7, MCF-7/ADR and MCF-7/Akt, were used as models to test the effects of SZ-685C. We found that SZ-685C suppressed the Akt pathway and induced apoptosis in MCF-7/ADR and MCF-7/Akt cells that are resistant to ADR treatment, leading to antitumor effects both in vitro and in vivo. Our data suggest that use of SZ-685C might represent a potentially promising approach to the treatment of ADR-resistant breast cancer

MetaAdvDet: Towards Robust Detection of Evolving Adversarial Attacks

Deep neural networks (DNNs) are vulnerable to adversarial attack which is maliciously implemented by adding human-imperceptible perturbation to images and thus leads to incorrect prediction. Existing studies have proposed various methods to detect the new adversarial attacks. However, new attack methods keep evolving constantly and yield new adversarial examples to bypass the existing detectors. It needs to collect tens of thousands samples to train detectors, while the new attacks evolve much more frequently than the high-cost data collection. Thus, this situation leads the newly evolved attack samples to remain in small scales. To solve such few-shot problem with the evolving attack, we propose a meta-learning based robust detection method to detect new adversarial attacks with limited examples. Specifically, the learning consists of a double-network framework: a task-dedicated network and a master network which alternatively learn the detection capability for either seen attack or a new attack. To validate the effectiveness of our approach, we construct the benchmarks with few-shot-fashion protocols based on three conventional datasets, i.e. CIFAR-10, MNIST and Fashion-MNIST. Comprehensive experiments are conducted on them to verify the superiority of our approach with respect to the traditional adversarial attack detection methods.Comment: 10 pages, 2 figures, accepted as the conference paper of Proceedings of the 27th ACM International Conference on Multimedia (MM'19

Mapping 30-m Resolution Bioclimatic Variables During 1991–2020 Climate Normals for Hubei Province, the Yangtze River Middle Reaches

High-resolution bioclimatic data are crucial to providing fine-scaled insights into biodiversity assessment, forestry, and agricultural management. Existing global bioclimatic datasets often exhibit kilometer-level coarse resolution or have miss the data in recent decades, potentially resulting in the issues of lower spatial accuracy, limited information, and restricted applicability in fine-scaled studies. Hubei Province in Yangtze River Middle Reaches has sparse meteorological stations in high-altitude mountainous areas to map the high-resolution bioclimatic variables directly. This study developed a 30-year averaged bioclimatic dataset for Hubei Province during 1991–2020 at a 30-m spatial resolution, utilizing monthly temperatures and precipitation derived from a downscaling-calibration framework. The downscaling of 1-km resolution climate variables was achieved by using a random forest model with 30-m resolution terrain and spatial covariates. Then, the geographical differential analysis was applied to improve the accuracy of downscaled products by including additional ground data. The mean absolute errors of calibrated monthly maximum, mean, minimum temperatures, and precipitation based on ordinary kriging decreased from 0.74 °C, 0.47 °C, 0.47 °C, and 28.27 mm to 0.43 °C, 0.28 °C, 0.36 °C, and 21.43 mm, respectively. Finally, calibrated climate variables were employed to calculate 19 annual bioclimatic variables, which were subsequently averaged over the 30-year period. The constructed bioclimatic dataset exhibits high overall consistency with the WorldClim dataset according to pixel-based comparison (Spearman correlation coefficients >0.6), with differences mainly attributed to the superior local accuracy of our dataset and climate changes. The dataset will provide fine-scaled, updated, and reliable data supports for local-related studies and decision making

Phototheranostics for NIR fluorescence image guided PDT/PTT with extended conjugation and enhanced TICT

Introducing donor and acceptor into conjugated system can facilitate the intersystem crossing (ISC) rate to increase the generation of ROS. Twisted intramolecular charge transfer (TICT) state could favor enhance the nonradiative transition and photothermal conversion efficiency (PCE). Herein, diketopyrrolopyrrole (DPP) core functionalized benzene (PDDP), thiophene (TDPP), triphenylamine-conjugated benzene (TPA-PDDP) and thiophene (TPA-TDPP) derivatives were designed and synthesized. Electrochemistry experiments revealed the heavy atom effect and the introduction of triphenylamine reduced the energy level of TPA-TDPP and improved the ability to generate 1O2 (1O2 QY = 50%). In addition, in the aggregated state, introduction of thiophene, triphenylamine, and long alkyl chains promoted the twisting effect, preventing the intermolecular π-π interaction and enhancing the PCE of TPA-TDPP (38.7%). In vivo fluorescence imaging showed that TPA-TDPP NPs can target the tumor site with the enhanced permeability and retention (EPR) effect and presented excellent synergistic photodynamic/photothermal therapy