Aerodynamic System Machine Learning Modeling with Gray Wolf Optimization Support Vector Regression and Instability Identification Strategy of Wavelet Singular Spectrum.

The prediction of a stall precursor in an axial compressor is the basic guarantee to the stable operation of an aeroengine. How to predict and intelligently identify the instability of the system in advance is of great significance to the safety performance and active control of the aeroengine. In this paper, an aerodynamic system modeling method combination with the wavelet transform and gray wolf algorithm optimized support vector regression (WT-GWO-SVR) is proposed, which breaks through the fusion technology based on the feature correlation of chaotic data.

Genome-Wide Analysis of Gene Expression Noise Brought About by Transcriptional Regulation in .

The part of expression noise that is brought about by transcriptional regulation (represented here as NTR) is an important criterion for estimating the regulatory mode of a gene. However, characterization of NTR is an under-explored area, and there is little knowledge regarding the genome-wide NTR in the model pathogen Pseudomonas aeruginosa. Here, with a library of dual-color transcriptional reporters, we estimated the NTR for over 90% of the promoters in P.

An adaptive tracking illumination system for optogenetic control of single bacterial cells.

Single-cell behaviors are essential during early-stage biofilm formation. In this study, we aimed to evaluate whether single-cell behaviors could be precisely and continuously manipulated by optogenetics. We thus established adaptive tracking illumination (ATI), a novel illumination method to precisely manipulate the gene expression and bacterial behavior of Pseudomonas aeruginosa on the surface at the single-cell level by using the combination of a high-throughput bacterial tracking algorithm, optogenetic manipulation, and adaptive microscopy.

Programmable living assembly of materials by bacterial adhesion.

The field of engineered living materials aims to construct functional materials with desirable properties of natural living systems. A recent study demonstrated the programmed self-assembly of bacterial populations by engineered adhesion. Here we use this strategy to engineer self-healing living materials with versatile functions.

Engineering Gac/Rsm Signaling Cascade for Optogenetic Induction of the Pathogenicity Switch in .

Bacterial pathogens operate by tightly controlling the pathogenicity to facilitate invasion and survival in host. While small molecule inducers can be designed to modulate pathogenicity to perform studies of pathogen-host interaction, these approaches, due to the diffusion property of chemicals, may have unintended, or pleiotropic effects that can impose limitations on their use. By contrast, light provides superior spatial and temporal resolution.

Optogenetic Modification of Enables Controllable Twitching Motility and Host Infection.

Cyclic adenosine monophosphate (cAMP) is an important secondary messenger that controls carbon metabolism, type IVa pili biogenesis, and virulence in . Precise manipulation of bacterial intracellular cAMP levels may enable tunable control of twitching motility or virulence, and optogenetic tools are attractive because they afford excellent spatiotemporal resolution and are easy to operate. Here, we developed an engineered strain (termed ) with light-dependent intracellular cAMP levels through introducing a photoactivated adenylate cyclase gene () into bacteria.

A Synthetic Genetic Circuit Enables Precise Quantification of Direct Repeat Deletion in Bacteria.

Quantification of the rate of direct repeat deletion (DRD) is an important aspect in the research of DNA rearrangement. The widely used tetracycline selection method usually introduces antibiotic pressure to the tested organism, which may interfere with the DRD process. Also the length of repeat arm (LRA) is limited by the length of the TetR coding sequence.

Simultaneous Visualization of Multiple Gene Expression in Single Cells Using an Engineered Multicolor Reporter Toolbox and Approach of Spectral Crosstalk Correction.

Synthetic biology aims to make biology easier to engineer and focuses on the design and construction of core components that can be modeled, understood, and tuned to meet specific performance criteria, and the assembly of these smaller parts and devices into larger integrated systems to solve specific problems. Here, we designed and engineered a multicolor fluorescent reporter toolbox to simultaneously monitor the activities of multiple genes in single cells. The toolbox contained standardized and well-characterized genetic building blocks for the convenient and reproducible assembly of multiple promoter-reporter fusions (ranging from 1 to 4) into a single plasmid.

Carbon Starvation Induces the Expression of PprB-Regulated Genes in Pseudomonas aeruginosa.

can cause severe infections in humans. This bacterium often adopts a biofilm lifestyle that is hard to treat. In several previous studies, the PprA-PprB two-component system (TCS), which controls the expression of type IVb pili, BapA adhesin, and CupE fimbriae, was shown to be involved in biofilm formation (M.

Imaging the Separation Distance between the Attached Bacterial Cells and the Surface with a Total Internal Reflection Dark-Field Microscope.

The attachment of bacterial cells to a surface is implicated in the formation of biofilms. Although the surface-related behaviors in this process, such as single cell motility and surface sensing, have been investigated intensively, the precise information of separation distance between the attached cells and the surface has remained unclear. Here, we set a prism-based total internal reflection dark-field microscope (p-TIRDFM) combined with the microfluidic method to image the separation distance of single attached cells.

Heterogeneity in surface sensing suggests a division of labor in populations.

The second messenger signaling molecule cyclic diguanylate monophosphate (c-di-GMP) drives the transition between planktonic and biofilm growth in many bacterial species. has two surface sensing systems that produce c-di-GMP in response to surface adherence. Current thinking in the field is that once cells attach to a surface, they uniformly respond by producing c-di-GMP.

Dual-Color Fluorescent Timer Enables Detection of Growth-Arrested Pathogenic Bacterium.

We present a method capable of detecting single slow-growing and growth-arrested cells in a bacterial culture composed of physiologically and phenotypically different cells. Unlike the use of transcriptional reporters to gauge the metabolic activities in cells, here, we fuse two different fluorescent proteins with distinctive maturation rates to construct a timer to directly determine the growth rate of single Pseudomonas aeruginosa cells. We demonstrate that the dual-color fluorescent timer can indicate the slow-growing and growth-arrested cells from bacterial cultures in the presence of various environmental stresses, including nutrient starvation or antibiotic treatments, which greatly expand the methods for detecting and isolating persister cells.

Differential Production of Psl in Planktonic Cells Leads to Two Distinctive Attachment Phenotypes in Pseudomonas aeruginosa.

Exponentially growing bacteria in a well-mixed planktonic culture are generally assumed to be physiologically and phenotypically uniform and distinct from their genetically identical counterparts living in biofilms. Using a combination of high spatiotemporal microscopy and a bacterial tracking algorithm, in this study, we showed that planktonic cells of differently attached to surfaces even when they remained in the exponential phase. We consistently observed that fast- and slow-attaching phenotypes coexist in planktonic cells, regardless of their growth phase.

Bioprinting Living Biofilms through Optogenetic Manipulation.

In this paper, we present a new strategy for microprinting dense bacterial communities with a prescribed organization on a substrate. Unlike conventional bioprinting techniques that require bioinks, through optogenetic manipulation, we directly manipulated the behaviors of Pseudomonas aeruginosa to allow these living bacteria to autonomically form patterned biofilms following prescribed illumination. The results showed that through optogenetic manipulation, patterned bacterial communities with high spatial resolution (approximately 10 μm) could be constructed in 6 h.

Conditional privatization of a public siderophore enables Pseudomonas aeruginosa to resist cheater invasion.

Understanding the mechanisms that promote cooperative behaviors of bacteria in their hosts is of great significance to clinical therapies. Environmental stress is generally believed to increase competition and reduce cooperation in bacteria. Here, we show that bacterial cooperation can in fact be maintained because of environmental stress.

Strong Shear Flow Persister Bacteria Resist Mechanical Washings on the Surfaces of Various Polymer Materials.

Environmental bacteria persistently exist in hospitals and thereby often contaminate biomedical devices, which usually causes device-associated infections that have become a major cause of patient illness and death in the hospital. In this study, for the first time, the identification of strong shear flow persister (SSP) cells in Pseudomonas aeruginosa is reported. Unlike common persister cells that are highly tolerant to antibiotics, it is reported that the SSP cells can resist mechanical washings on the surfaces of various polymer materials and can form distinctive biofilms that are tolerant to high doses of aminoglycoside antibiotics.

Optogenetics Manipulation Enables Prevention of Biofilm Formation of Engineered Pseudomonas aeruginosa on Surfaces.

Synthetic biologists have attempted to solve real-world problems, such as those of bacterial biofilms, that are involved in the pathogenesis of many clinical infections and difficult to eliminate. To address this, we employed a blue light responding system and integrated it into the chromosomes of Pseudomonas aeruginosa. With making rational adaptions and improvements of the light-activated system, we provided a robust and convenient means to spatiotemporally control gene expression and manipulate biological processes with minimal perturbation in P.