Multicellular Synthetic Biology in Mammalian Systems

In multicellular organisms, different types of cells use intercellular signals to communicate and regulate population dynamics, and further coordinate complex behaviors. This presents a rarely tapped into potential for mammalian synthetic biology, which was largely restricted to engineering a single cell type in the past to mimic and use similar multicellular designs to achieve more functionalities. However, with current synthetic biology tools and designs, there are several major challenges to achieve a multicellular circuit. Challenges include precise and tunable control over cell type switching, having an orthogonal cell-cell communication signal, and robust control of cell populations. To address these challenges, this thesis presents a system for tunable regulating of gene expression with DNA methylation, an auxin-based module for mammalian cell-cell communication, and a robust circuit for population control in mammalian cells. I further applied these work to engineering immune cells to show the potential of multicellular circuits in immunotherapies. Together, these works demonstrated the possibility of constructing multicellular circuits in mammalian systems, and that multicellular circuit can further extend the scope of synthetic biology to achieve more complex functions.</p

Effect of β3-adrenoceptor on cardiac fibrosis in rat cardiac fibroblast cells and its potential mechanism

Purpose: To investigate the effect of β3-adrenoceptors (β3-AR) up-regulation on fibrosis in cardiac fibroblast cells in rats and its potential mechanism.Methods: Cardiac fibroblast cells (CFB) were isolated and identified from rats’ hearts. The β3-ARupregulated cardiac fibroblast cells were constructed by lentiviral transfection technology. Thereafter, Ang II was used to induce fibrosis in cardiac fibroblast cells, and subsequently, Western blot assay was performed to investigate fibrosis related marker proteins (TGF-β, Smad-2, p-Smad-2, Col-I and Col-III) in cardiac fibroblast cells.Results: β3-AR up-regulated cardiac fibroblast cells were successfully constructed. Furthermore, the results show that up-regulation of β3-AR increased the expressions of TGF-β, p-Smad-2, Col-I and Col- III proteins in Ang II treated cardiac fibroblast cells.Conclusion: The results suggest that up-regulation of β3-AR aggravates fibrosis of cardiac fibroblast cells. In other words, inhibition of β3-AR expressions in cardiac tissues would be beneficial for treating cardiac fibrosis and its related cardiac diseases.Keywords: Cardiac fibrosis, β3-AR, TGF/Smads, Col-I/III, Cardiac fibroblast cell

Uncovering the role of superplasticizer in developing nano-engineered ultra-high-performance concrete

The effect of superplasticizer (SP) on the performance of ultra-high-performance concrete (UHPC) and ultra-high-performance fiber-reinforced concrete (UHPFRC) has been systematically investigated aiming to optimize the use of SP. The slump flow, and V-funnel time were employed to evaluate the impact of SP on the workability, while compressive strength had been used for mechanical property. Moreover, the packing density, as well as the water film thickness had been calculated to uncover the mechanism. The obtained results indicated that the addition of SP improved the workability of specimens with an ultimate-low water-to-binder (W/B) ratio, while it benefited the strength development of UHPC with a lower W/B ratio. This novel phenomenon (SP enhances the mechanical properties of UHPC) is due to the fact that SP reduced the water film thickness and enhanced the packing structure, therefore resulting in an increased compressive strength. For UHPFRC, similar trends can be witnessed regarding the flowability. However, the alternation of the fresh behavior of UHPFRC, attributed to the inclusion of SP, had an obvious impact on the fiber distribution, which altered the strength development of UHPFRC. This study revealed the significant effect of SP on the performance, especially on the strength development, of UHPC and UHPFRC

Changes in Quality Characteristics of Snakehead Surimi during Fermentation

In this study, the effects of Pediococcus pentosaceus inoculation on the quality characteristics of snakehead surimi during fermentation were analyzed in comparison with natural fermentation. The quality of fermented surimi was evaluated in terms of pH, total acid, total volatile basic nitrogen (TVB-N), fatty acids, color difference, texture, amino acids and sensory scores. The results showed that pH declined and total acid content gradually increased during fermentation. After fermentation for 48 h, total acid content in the inoculated fermentation group increased by 52.29% when compared with that in the natural fermentation group. Compared with the natural fermentation group, the increase in TVB-N content was significantly inhibited in the inoculated fermentation group. The content of saturated fatty acids increased during natural fermentation, but decreased during inoculated fermentation. The content of monounsaturated fatty acids was lower while the content of polyunsaturated fatty acids was higher in the inoculated fermentation group than in the natural fermentation group at the end of fermentation. The inoculated fermentation group showed an increase in L* value and the absolute values of hardness and adhesiveness, and increased the contents of total essential amino acids and umami amino acids in surimi samples and the essential amino acid index from 73.9 to 74.8. After fermentation for 48 h, the scores for odor, color and overall acceptability in the inoculated fermentation group were higher than those in the natural fermentation group, which were significantly correlated with quality characteristics. Therefore, the quality of snakehead surimi can be better improved by fermentation with P. pentosaceus

Synthetic mammalian signaling circuits for robust cell population control

In multicellular organisms, cells actively sense, respond to, and control their own population density. Synthetic mammalian quorum sensing circuits could provide insight into principles of population control and improve cell therapies. However, a key challenge is avoiding their inherent sensitivity to “cheater” mutations that evade control. Here, we repurposed the plant hormone auxin to enable orthogonal mammalian cell-cell communication and quorum sensing. Further, we show that a “paradoxical” circuit design, in which auxin stimulates and inhibits net cell growth at different concentrations, achieves population control that is robust to cheater mutations, controlling growth for 43 days of continuous culture. By contrast, a non-paradoxical control circuit limited growth but was susceptible to mutations. These results establish a foundation for future cell therapies that can respond to and control their own population sizes

ChatBBNJ: a question–answering system for acquiring knowledge on biodiversity beyond national jurisdiction

The marine biodiversity in Areas beyond national jurisdiction (ABNJ), encompassing approximately two-thirds of the global ocean, is persistently declining. In 2023, the agreement on the Conservation and Sustainable Use of Marine Biodiversity of Areas Beyond National Jurisdiction (BBNJ) was officially adopted. Implementing the BBNJ Agreement has the potential to effectively meet global needs for preserving marine biodiversity. Nevertheless, the implementation requires dealing with thousands of legal clauses, and the parties participating in the process lack adequate means to acquire knowledge connected to BBNJ. This paper introduces ChatBBNJ, a highly efficient question-answering system that combines a novel data engineering technique with large language models (LLMs) of Natural Language Processing (NLP). The system aims to efficiently provide stakeholders with BBNJ-related knowledge, thereby facilitating and enhancing their comprehension and involvement with the subject matter. The experimental results demonstrate that the proposed ChatBBNJ exhibits superior expertise in the BBNJ domain, outperforming baseline models in terms of precision, recall, and F1-scores. The successful deployment of the suggested system is expected to greatly assist stakeholders in acquiring BBNJ knowledge and facilitating the effective implementation of the BBNJ Agreement. Therefore, this is expected to contribute to the conservation and sustainable use of marine biodiversity in ABNJ

A two-branch cloud detection algorithm based on the fusion of a feature enhancement module and Gaussian mixture model

Accurate cloud detection is an important step to improve the utilization rate of remote sensing (RS). However, existing cloud detection algorithms have difficulty in identifying edge clouds and broken clouds. Therefore, based on the channel data of the Himawari-8 satellite, this work proposes a method that combines the feature enhancement module with the Gaussian mixture model (GMM). First, statistical analysis using the probability density functions (PDFs) of spectral data from clouds and underlying surface pixels was conducted, selecting cluster features suitable for daytime and nighttime. Then, in this work, the Laplacian operator is introduced to enhance the spectral features of cloud edges and broken clouds. Additionally, enhanced spectral features are input into the debugged GMM model for cloud detection. Validation against visual interpretation shows promising consistency, with the proposed algorithm outperforming other methods such as RF, KNN and GMM in accuracy metrics, demonstrating its potential for high-precision cloud detection in RS images