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Xing, X.-h.

Publications and source records attributed to Xing, X.-h..

3 recordsLinked to original sources

Deep-learning-assisted Sort-Seq enables high-throughput profiling of gene expression characteristics with high precision

As an essential physiological process, gene expression determines the function of each cell. However, owing to the complex nondeterministic and nonlinear nature of gene expression, the steady-state intracellular protein abundance of a clonal population forms a distribution. The characteristics of this distribution, including expression strength and noise, are closely related to cellular behavior. Therefore, quantitative description of these characteristics is an important goal in biology. This task, however, has so far relied on arrayed methods, which are time-consuming and labor-intensive. To address this issue, we propose a deep-learning-assisted Sort-Seq approach (dSort-Seq) in this work, enabling high-throughput profiling of expression properties with high precision. We demonstrated the validity of dSort-Seq for large-scale assaying of the dose-response relationships of biosensors. In addition, we comprehensively investigated the contribution of transcription and translation to noise production in E. coli, from which we discovered that the expression noise is strongly coupled with the mean expression level instead of translation strength, even in the case of weak transcription. We also discovered that the transcriptional interference caused by overlapping RpoD-binding sites contributes to noise production, which suggested the existence of a simple and feasible noise control strategy in E. coli. Overall, dSort-Seq is able to efficiently determine the strength-noise landscape, which has promising applications in studies related to gene expression.

genetics↗

Genome-scale mapping of functional genes and loci in bacteria for industrial phenotypes

Base editing, the targeted introduction of point mutations into cellular DNA, holds promise for improving genome-scale functional genome screening to single-nucleotide resolution. Current efforts in prokaryotes, however, remain confined to loss-of-function screens using the premature stop codons-mediated gene inactivation library, which falls far short of fully releasing the potential of base editors. Here, we developed a base editor-mediated functional single nucleotide variant screening pipeline in E. coli. We constructed a library with 31,123 sgRNAs targeting 462 stress response-related genes in E. coli, and screened for adaptive mutations under isobutanol and furfural selective conditions. Guided by the screening results, we successfully identified several known and novel functional mutations. Our pipeline might be expanded to the optimization of other phenotypes or the strain engineering in other microorganisms.

bioengineering↗

Microbial microdroplet culture system (MMC): an integrated platform for automated, high-throughput microbial cultivation and adaptive evolution

Conventional microbial cell cultivation techniques are typically labor intensive, low throughput, and poor parallelization, rendering them inefficient. The development of automated, modular microbial cell micro-cultivation systems, particularly those employing droplet microfluidics, has gained attention for their high-throughput, parallel and highly efficient cultivation capabilities. Here, we report the development of a microbial microdroplet culture system (MMC), which is an integrated platform for automated, high-throughput cultivation and adaptive evolution of microorganisms. We demonstrated that the MMC yielded both accurate and reproducible results for the manipulation and detection of droplets. The superior performance of MMC for microbial cell cultivation was validated by comparing the growth curves of six microbial strains grown in MMC, conventional shake flasks or well plates. The highest incipient growth rate for all six microbial cell lines was achieved using MMC. We also conducted an 18-day process of adaptive evolution of a methanol-essential Escherichia coli strain in MMC and obtained two strains exhibiting higher growth rates compared with the parent strain. Our study demonstrates the power of MMC to provide an efficient and reliable approach for automated, high-throughput microbial cultivation and adaptive evolution.

bioengineering↗