89 research outputs found

    Identification of lipid droplet structure-like/resident proteins in Caenorhabditis elegans.

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    The lipid droplet (LD) is a cellular organelle that stores neutral lipids in cells and has been linked with metabolic disorders. Caenorhabditis elegans has many characteristics which make it an excellent animal model for studying LDs. However, unlike in mammalian cells, no LD structure-like/resident proteins have been identified in C. elegans, which has limited the utility of this model for the study of lipid storage and metabolism. Herein based on three lines of evidence, we identified that MDT-28 and DHS-3 previously identified in C. elegans LD proteome were two LD structure-like/resident proteins. First, MDT-28 and DHS-3 were found to be the two most abundant LD proteins in the worm. Second, the proteins were specifically localized to LDs and we identified the domains responsible for this targeting in both proteins. Third and most importantly, the depletion of MDT-28 induced LD clustering while DHS-3 deletion reduced triacylglycerol content (TAG). We further characterized the proteins finding that MDT-28 was ubiquitously expressed in the intestine, muscle, hypodermis, and embryos, whereas DHS-3 was expressed mainly in intestinal cells. Together, these two LD structure-like/resident proteins provide a basis for future mechanistic studies into the dynamics and functions of LDs in C. elegans

    EGFR deficiency leads to impaired self-renewal and pluripotency of mouse embryonic stem cells

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    Background Self-renewal and pluripotency are considered as unwavering features of embryonic stem cells (ESCs). How ESCs regulate the self-renewal and differentiation is a central question in development and regenerative medicine research. Epidermal growth factor receptor (EGFR) was identified as a critical regulator in embryonic development, but its role in the maintenance of ESCs is poorly understood. Methods Here, EGFR was disrupted by its specific inhibitor AG1478 in mouse ESCs (mESCs), and its self-renewal and pluripotency were characterized according to their proliferation, expression of pluripotency markers, embryoid body (EB) formation, and mRNA expression patterns. We also used another EGFR inhibitor (gefitinib) and RNA interference assay to rule out the possibility of non-specific effects of AG1478. Results EGFR inhibition by AG1478 treatment in mESCs markedly reduced cell proliferation, caused cell cycle arrest at G0/G1 phase, and altered protein expressions of the cell cycle regulatory genes (CDK2 (decreased 11.3%) and proliferating cell nuclear antigen (decreased 25.2%)). The immunoreactivities and protein expression of pluripotency factors (OCT4 (decreased 26.9%)) also dramatically decreased, while the differentiation related genes (GATA4 (increased 1.6-fold)) were up-regulated in mESCs after EGFR inhibition. Meanwhile, EGFR inhibition in mESCs disrupted EB formation, indicating its impaired pluripotency. Additionally, the effects observed by EGFR inhibition with another inhibitor gefitinib and siRNA were consistent with those observed by AG1478 treatment in mESCs. These effects were manifested in the decreased expression of proliferative and pluripotency-related genes and the increased expression of genes involved in differentiation. Moreover, RNA-seq analysis displayed that transcript profiling was changed significantly after EGFR inhibition by AG1478. A large number of differentially expressed genes were involved in cell cycle, apoptotic process, epigenetic modification, and metabolic process, which were related to self-renewal and pluripotency, confirming that EGFR deficiency impaired self-renewal and pluripotency in mESCs. Conclusions Taken together, our results demonstrated the importance of EGFR in guarding the stemness of mESCs

    Influence of Appeal Type and Message Framing on Residents’ Intent to Engage in Pro-Environmental Behavior

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    In this intervention study, we examined the effects and psychological processes of different types of messaging intended to promote waste-separation behavior on the intent of residents to separate household waste and to engage in other pro-environmental behaviors (PEBs). Based on three studies (one survey with 76 residents and two experiments with 446 residents) in China, our results revealed that environmental appeals increased residents’ intent to separate waste and engage in other PEBs, whereas monetary incentives had no effect. Although the main effects of the framing of messages on the intent to separate waste and other PEBs were not significant, we found an interactive effect of appeal type and message framing. When matched with loss framing, an environmental appeal indirectly generated a stronger positive impact by stimulating an individual’s environmental risk perception. When monetary incentives matched with loss framing, individual pro-environmental identity weakened, thereby inhibiting the positive impact on intent to separate waste. With this study, we provide important theoretical support for the selection and optimization of waste-separation intervention strategies and guidance for persuading residents to engage in more PEBs

    Progress, problems and prospects of porcine pluripotent stem cells

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    Pluripotent stem cells (PSCs), including embryonic stem cells (ESCs) and induced PSCs (iPSCs), can differentiate into cells of the three germ layers, suggesting that PSCs have great potential for basic developmental biology research and wide applications for clinical medicine. Genuine ESCs and iPSCs have been derived from mice and rats, but not from livestock such as the pig─an ideal animal model for studying human disease and regenerative medicine due to similarities with human physiologic processes. Efforts to derive porcine ESCs and iPSCs have not yielded high-quality PSCs that can produce chimeras with germline transmission. Thus, exploration of the unique porcine gene regulation network of preimplantation embryonic development may permit optimization of in vitro culture systems for raising porcine PSCs. Here we summarize the recent progress in porcine PSC generation as well as the problems encountered during this progress and we depict prospects for generating porcine naive PSCs

    Spatial Planning Strategies for Wetlands Based on a Multimethod Approach: The Example of Tianjin in China

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    Wetlands form a crucial component of ecosystems, and wetland restoration serves as an effective strategy for promoting sustainable urban development. Spatial support is essential for wetland restoration, meaning that research on wetland spatial planning is of considerable importance. Existing studies on wetland spatial planning primarily focus on the analysis of wetland spatial distribution characteristics, with limited exploration of wetland spatial relationships. This paper aims to explore the potential of utilizing both spatial distribution characteristics and spatial relationships to identify wetland spatial issues, thereby facilitating the formulation of wetland spatial planning strategies. Using Tianjin City as a case study, this research applies nearest neighbor analysis, the geographic concentration index, the Gini index, and kernel density analysis to identify the spatial distribution characteristics of wetlands in Tianjin. Additionally, spatial autocorrelation analysis and connectivity analysis are employed to identify the interrelationships among wetlands in Tianjin. Based on the results derived from the analysis of spatial distribution characteristics and spatial relationships, wetland spatial planning strategies are proposed. The effectiveness of these strategies is validated using methods that consider both spatial distribution characteristics and spatial relationships. The findings reveal that, although wetlands in Tianjin are widely distributed, large wetland patches are primarily concentrated in areas with abundant water resources, while the six districts within the city have few or no large patches of wetlands. The spatial distribution of wetlands is highly uneven, exhibiting patterns of high–high aggregation and low–low aggregation. The number of connecting paths between wetland patches is relatively low, indicating a generally low overall connectivity. While medium-sized and larger wetland patches maintain the connectivity of existing wetlands in Tianjin, small wetlands that serve as stepping stones are lacking. Following the implementation of planning strategies, there would be an increase in the wetland area in Tianjin, accompanied by significant improvements in the spatial distribution pattern and spatial relationships of the wetlands

    Study on Dynamic Load of Air-Conditioning System in Subway Station Based on Hourly Passenger Flow

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    The research focuses on the air-conditioning system in a public area of a subway station. To address this, an optimization model based on the grid time segmentation method was constructed, specifically a GM (1,1) model. We explored the influence of the hourly passenger flow fluctuation on the load of the subway air-conditioning system, obtained the dynamic change law of the air conditioning system load in the subway station, and then dynamically adjusted the air conditioning system according to the dynamic change law to reduce the operation energy consumption of the system. Through the analysis of the simulation results, the model predicted that compared with the actual passenger flow data, the average maximum relative error was 14.97%. On this basis, the change law of the dynamic load of the subway air-conditioning system which caused by the change in passenger flow from time to time could be calculated and analyzed. Compared with the calculated load of the air conditioning system, the working day load was decreased by 1469.77 kW, or 22.00%. The findings indicate that in response to the dynamic load of fluctuations, timely adjustment of the air supply parameter of the air-conditioning system offers a significant reference point for optimizing energy efficiency in subway stations

    Exemplar-free Class Incremental Learning via Discriminative and Comparable One-class Classifiers

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    The exemplar-free class incremental learning requires classification models to learn new class knowledge incrementally without retaining any old samples. Recently, the framework based on parallel one-class classifiers (POC), which trains a one-class classifier (OCC) independently for each category, has attracted extensive attention, since it can naturally avoid catastrophic forgetting. POC, however, suffers from weak discriminability and comparability due to its independent training strategy for different OOCs. To meet this challenge, we propose a new framework, named Discriminative and Comparable One-class classifiers for Incremental Learning (DisCOIL). DisCOIL follows the basic principle of POC, but it adopts variational auto-encoders (VAE) instead of other well-established one-class classifiers (e.g. deep SVDD), because a trained VAE can not only identify the probability of an input sample belonging to a class but also generate pseudo samples of the class to assist in learning new tasks. With this advantage, DisCOIL trains a new-class VAE in contrast with the old-class VAEs, which forces the new-class VAE to reconstruct better for new-class samples but worse for the old-class pseudo samples, thus enhancing the comparability. Furthermore, DisCOIL introduces a hinge reconstruction loss to ensure the discriminability. We evaluate our method extensively on MNIST, CIFAR10, and Tiny-ImageNet. The experimental results show that DisCOIL achieves state-of-the-art performance
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