30 research outputs found
mTOR has a developmental stage-specific role in mitochondrial fitness independent of conventional mTORC1 and mTORC2 and the kinase activity.
No full textThe mammalian target of rapamycin (mTOR), present in mTOR complex 1 (mTORC1) and mTORC2, is a serine/threonine kinase that integrates nutrients, growth factors, and cellular energy status to control protein synthesis, cell growth, survival and metabolism. However, it remains elusive whether mTOR plays a developmental stage-specific role in tissue development and whether mTOR can function independent of its complexes and kinase activity. In this study, by inducible genetic manipulation approach, we investigated the role of mTOR and its dependence on mTOR complexes and kinase activity in mitochondrial fitness of early, progenitor stage (lineage-negative; Lin-) versus later, lineage-committed stage (lineage-positive; Lin+) of hematopoietic cells. We found that oxidative phosphorylation (OXPHOS), ATP production and mitochondrial DNA synthesis were decreased in mTOR-/- Lin- cells but increased in mTOR-/- Lin+ cells, suggesting that mTOR plays a developmental stage-specific role in OXPHOS, ATP production and mitochondrial DNA synthesis. In contrast to mTOR deletion, simultaneous deletion of Raptor, a key component of mTORC1, and Rictor, a key component of mTORC2, led to increased mitochondrial DNA in Lin- cells and decreased mitochondrial DNA and ATP production in Lin+ cells, suggesting that mTOR regulates mitochondrial DNA synthesis in Lin- and Lin+ cells and ATP production in Lin+ cells independent of mTORC1 and mTORC2. Similar to mTOR deletion, deletion of Raptor alone attenuated glycolysis and increased mitochondrial mass and mitochondrial membrane potential in Lin- cells and increased mitochondrial mass and OXPHOS in Lin+ cells, whereas deletion of Rictor alone had no effect on these mitochondrial parameters in Lin- and Lin+ cells, suggesting that mTOR regulates glycolysis and mitochondrial membrane potential in Lin- cells, OXPHOS in Lin+ cells, and mitochondrial mass in both Lin- and Lin+ cells dependent on mTORC1, but not mTORC2. Either Raptor deficiency or Rictor deficiency recapitulated mTOR deletion in decreasing OXPHOS in Lin- cells and glycolysis in Lin+ cells, suggesting that mTOR regulates OXPHOS in Lin- cells and glycolysis in Lin+ cells dependent on both mTORC1 and mTORC2. Finally, mice harboring a mTOR kinase dead D2338A knock-in mutant showed decreased glycolysis in Lin+ cells, as seen in mTOR-/- Lin+ cells, but no change in glycolysis in Lin- cells, in contrast to the decreased glycolysis in mTOR-/- Lin- cells, suggesting that mTOR regulates glycolysis in Lin+ cells dependent on its kinase activity, whereas mTOR regulates glycolysis in Lin- cells independent of its kinase activity
Dialysis membrane enclosed laccase catalysis combines a controlled conversion rate and recyclability without enzyme immobilization
No full textLaccase is a versatile multicopper oxidase that holds great promise for many biotechnological applications. For such applications, it is essential to explore good biocatalytic systems for high activity and recyclability. The feasibility of membrane enclosed enzymatic catalysis (MEEC) for enzyme recycling with laccase was evaluated. The dialysis membrane enclosed laccase catalysis (DMELC) was tested for the conversion of the non-phenolic model substrate 2,2′-Azino-bis(3-ethylbenzthiazoline-6-sulfonate) (ABTS). Trametes versicolor laccase was found to be completely retained by the dialysis membrane during the process. The ABTS total conversion after DMELC reached the same values as the batch reaction of the enzyme in solution. The efficiency of DMELC conversion of ABTS under different process conditions including shaking speed, temperature, ABTS concentration and pH was investigated. The repetitive dialysis minimally affected the activity and the protein content of the enclosed laccase. DMELC retained 70.3 ± 0.8% of its initial conversion after 5 cycles. The usefulness of MEEC extends to other enzymes with the benefit of superior activity of an enzyme in solution and the recyclability which is normally only obtained with immobilized enzymes.[Figure not available: see fulltext.]BT/Biocatalysi
RhoA is required for bone marrow B cell development.
No full text<p>(A) <i>Mx-Cre; RhoA<sup>flox/flox</sup>(RhoA<sup>−/−</sup>)</i> mice were injected with polyI:C to delete RhoA in HSCs (left). <i>RhoA<sup>flox/flox</sup></i> mice were used as control and also subjected to polyI:C injection. Whole bone marrow was isolated from <i>RhoA<sup>−/−</sup></i> and control mice and analyzed for RhoA expression by Western blot (right). (B) Bone marrow cells from <i>RhoA<sup>−/−</sup></i> and control mice were stained for IL-7R, lineage (Lin) markers (B220, CD3, CD4, CD8, Gr1, CD11b and TER119), Sca-1, and c-Kit followed by flow cytometry analysis. Common lymphoid progenitor (CLP) cells (Sca1<sup>+</sup>c-kit<sup>+</sup>) were gated from a Lin<sup>−</sup>IL-7R<sup>+</sup> cell population (left). The number of CLPs was calculated by multiplying the total number of bone marrow cells by the percentage of CLP cells (right). n = 4. (C) Bone marrow cells from <i>RhoA<sup>−/−</sup></i> and control mice were stained with antibodies against B220 and IgM and analyzed by flow cytometry (left). The number of B cell subsets was calculated by multiplying the total number of bone marrow cells by the percentage of each subset of cells (right). n = 4. Error bars represent mean ± SD. **p<0.01. *p<0.05. Statistical analysis was performed using a Student's unpaired t-test with a two-tailed distribution.</p
Microplastics in three typical benthic species from the Arctic: Occurrence, characteristics, sources, and environmental implications
No full text12 Pág.
Centro de Investigación en Sanidad Animal (CISA)Microplastics (MPs) in the Arctic have raised increasing concern, but knowledge on MP contamination in benthic organisms from Arctic shelf regions, e.g., the Chukchi Sea is still limited. Therefore, the present study investigated the occurrence, characteristics, sources, and environmental implications of MPs in the three most common benthic species, namely sea anemone (Actiniidae und.), deposit-feeding starfish (Ctenodiscus crispatus), and snow crab (Chionoecetes opilio), from the Chukchi Sea. The abundances of MPs in the three benthic species were significantly greater than those from the Bering Sea, but lower than those from other regions globally. The top three compositions of MPs in the three species were polyester, nylon, and polyethylene terephthalate. The detection limit for MP size in the present study was 0.03 mm and the mean size of MP in the three species was 0.89 ± 0.06 mm. The surfaces of MPs found in the starfish and crabs were covered with many attachments, cracks, and hollows, while the surfaces of MPs found in the sea anemones were smooth, which was likely a consequence of different feeding behaviors. There was a significantly positive correlation between the abundances of MPs and other anthropogenic substances. The mean MP abundances in the sea anemones ranged from 0.2 items/individual to 1.7 items/individual, which was significantly higher than that in the deposit-feeding starfish (0.1-1.4 items/individual) and snow crabs (0.0-0.6 items/individual). Sea anemones inhabiting lower latitudes ingested relatively higher levels of MPs than those inhabiting higher latitudes. The MP abundances in the sea anemones are significantly and positively correlated with the seasonal reduced ratio of sea ice coverage from August to September. Our findings indicate that sea anemones could function as a bioindicator of MP pollution, and that the MPs in the benthos from the Chukchi Sea might originate from the melting sea ice, fishery activities and ocean currents.This work was sponsored by the Scientific Research Foundation of the Third Institute of Oceanography, Ministry of Natural Resources (No. 2018019), the Chinese Arctic and Antarctic Administration, the Ninth Chinese National Arctic Research Expedition (9th CHINARE-Arctic), the National Key Research and Development Program of China (No. 2019YFD0901101), the National Natural Science Foundation of China (Nos. 41977211 and 41722605), and the National Program on Global Change and Air-Sea Interaction (GASI-02-SCS-YDsum). CB was funded by SNF Post Doc Mobility Fellowship number P400PB_183824.Peer reviewe
A Visual Search Inspired Computational Model for Ship Detection in Optical Satellite Images
No full textIn this letter, we propose a novel computational model for automatic ship detection in optical satellite images. The model first selects salient candidate regions across entire detection scene by using a bottom-up visual attention mechanism. Then, two complementary types of top-down cues are employed to discriminate the selected ship candidates. Specifically, in addition to the detailed appearance analysis of candidates, a neighborhood similarity-based method is further exploited to characterize their local context interactions. Furthermore, the framework of our model is designed in a multiscale and hierarchical manner which provides a plausible approximation to a visual search process and reasonably distributes the computational resources. Experiments over panchromatic SPOT5 data prove the effectiveness and computational efficiency of the proposed model.Geochemistry & GeophysicsEngineering, Electrical & ElectronicRemote SensingImaging Science & Photographic TechnologySCI(E)EI8ARTICLE4749-753
Superconductivity in the vicinity of antiferromagnetic order in CrAs
No full textOne of the common features of unconventional superconducting systems such as the heavy-fermion, high transition-temperature cuprate and iron-pnictide superconductors is that the superconductivity emerges in the vicinity of long-range antiferromagnetically ordered state. In addition to doping charge carriers, the application of external pressure is an effective and clean approach to induce unconventional superconductivity near a magnetic quantum critical point. Here we report on the discovery of superconductivity on the verge of antiferromagnetic order in CrAs via the application of external pressure. Bulk superconductivity with T-c approximate to 2 K emerges at the critical pressure P-c approximate to 8 kbar, where the first-order antiferromagnetic transition at T-N approximate to 265 K under ambient pressure is completely suppressed. The close proximity of superconductivity to an antiferromagnetic order suggests an unconventional pairing mechanism for CrAs. The present finding opens a new avenue for searching novel superconductors in the Cr and other transition metal-based systems.Multidisciplinary SciencesSCI(E)[email protected]; [email protected]; [email protected]
A Multi-Level Cross-Attention Image Registration Method for Visible and Infrared Small Unmanned Aerial Vehicle Targets via Image Style Transfer
No full textSmall UAV target detection and tracking based on cross-modality image fusion have gained widespread attention. Due to the limited feature information available from small UAVs in images, where they occupy a minimal number of pixels, the precision required for detection and tracking algorithms is particularly high in complex backgrounds. Image fusion techniques can enrich the detailed information for small UAVs, showing significant advantages under extreme lighting conditions. Image registration is a fundamental step preceding image fusion. It is essential to achieve accurate image alignment before proceeding with image fusion to prevent severe ghosting and artifacts. This paper specifically focused on the alignment of small UAV targets within infrared and visible light imagery. To address this issue, this paper proposed a cross-modality image registration network based on deep learning, which includes a structure preservation and style transformation network (SPSTN) and a multi-level cross-attention residual registration network (MCARN). Firstly, the SPSTN is employed for modality transformation, transferring the cross-modality task into a single-modality task to reduce the information discrepancy between modalities. Then, the MCARN is utilized for single-modality image registration, capable of deeply extracting and fusing features from pseudo infrared and visible images to achieve efficient registration. To validate the effectiveness of the proposed method, comprehensive experimental evaluations were conducted on the Anti-UAV dataset. The extensive evaluation results validate the superiority and universality of the cross-modality image registration framework proposed in this paper, which plays a crucial role in subsequent image fusion tasks for more effective target detection
Realizing Small UAV Targets Recognition via Multi-Dimensional Feature Fusion of High-Resolution Radar
No full textFor modern radar systems, small unmanned aerial vehicles (UAVs) belong to a typical types of targets with ‘low, slow, and small’ characteristics. In complex combat environments, the functional requirements of radar systems are not only limited to achieving stable detection and tracking performance but also to effectively complete the recognition of small UAV targets. In this paper, a multi-dimensional feature fusion framework for small UAV target recognition utilizing a small-sized and low-cost high-resolution radar is proposed, which can fully extract and combine the geometric structure features and the micro-motion features of small UAV targets. For the performance analysis, the echo data of different small UAV targets was measured and collected with a millimeter-wave radar, and the dataset consists of high-resolution range profiles (HRRP) and micro-Doppler time–frequency spectrograms was constructed for training and testing. The effectiveness of the proposed method was demonstrated by a series of comparison experiments, and the overall accuracy of the proposed method can reach 98.5%, which demonstrates that the proposed multi-dimensional feature fusion method can achieve better recognition performance than that of classical algorithms and higher robustness than that of single features for small UAV targets
Fabrication of CaCl<sub>2</sub> · 6H<sub>2</sub>O/Na<sub>2</sub>SiO<sub>3</sub> · 9H<sub>2</sub>O composite phase change material for floor heating system
No full textInvestigating the effect of graphene nanoplatelets on the thermal conductivity of KAl(SO<sub>4</sub>)<sub>2</sub> · 12H<sub>2</sub>O
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