Single cell technologies for monitoring protein secretion heterogeneity.

Cell-to-cell heterogeneity presents challenges across various fields, from biomedicine to bioproduction, where precise cellular responses are vital. While single cell technologies have significantly enhanced our understanding of population heterogeneity, the predominant focus has been on monitoring intracellular compounds. Recognizing the added complexity introduced by the secretion system, in this review, we first provide a systematic overview of the distinct steps necessary for driving protein secretion.

Transport-controlled growth decoupling for self-induced protein expression with a glycerol-repressible genetic circuit.

Decoupling cell formation from recombinant protein synthesis is a potent strategy to intensify bioprocesses. Escherichia coli strains with mutations in the glucose uptake components lack catabolite repression, display low growth rate, no overflow metabolism, and high recombinant protein yields. Fast growth rates were promoted by the simultaneous consumption of glucose and glycerol, and this was followed by a phase of slow growth, when only glucose remained in the medium.

Fitness cost associated with cell phenotypic switching drives population diversification dynamics and controllability.

Isogenic cell populations can cope with stress conditions by switching to alternative phenotypes. Even if it can lead to increased fitness in a natural context, this feature is typically unwanted for a range of applications (e.g.

Advances in automated and reactive flow cytometry for synthetic biotechnology.

Automated flow cytometry (FC) has been initially considered for bioprocess monitoring and optimization. More recently, new physical and software interfaces have been made available, facilitating the access to this technology for labs and industries. It also comes with new capabilities, such as being able to act on the cultivation conditions based on population data.

Identification of small molecule antivirals against HTLV-1 by targeting the hDLG1-Tax-1 protein-protein interaction.

Human T-cell leukemia virus type-1 (HTLV-1) is the first pathogenic retrovirus discovered in human. Although HTLV-1-induced diseases are well-characterized and linked to the encoded Tax-1 oncoprotein, there is currently no strategy to target Tax-1 functions with small molecules. Here, we analyzed the binding of Tax-1 to the human homolog of the drosophila discs large tumor suppressor (hDLG1/SAP97), a multi-domain scaffolding protein involved in Tax-1-transformation ability.

Avoiding the All-or-None Response in Gene Expression During E. coli Continuous Cultivation Based on the On-Line Monitoring of Cell Phenotypic Switching Dynamics.

Different expression vectors are available for the effective production of recombinant proteins by bacterial populations. However, the productivity of such systems is limited by the inherent noise of the gene circuits used for the synthesis of recombinant products. An extreme case of cell-to-cell heterogeneity that has been previously reported for the ara- and lac-based expression systems in E.

Co-diet supplementation of low density polyethylene and honeybee wax did not influence the core gut bacteria and associated enzymes of Galleria mellonella larvae (Lepidoptera: Pyralidae).

The current plastic pollution throughout the world is a rising concern that demands the optimization of biodegradation processes. One avenue for this is to identify plastic-degrading bacteria and associated enzymes from the gut bacteria of insect models such as Tenebrio molitor, Plodia interpunctella or Galleria mellonella that have the ability to ingest and rapidly degrade polyethylene. Therefore, this study takes part in understanding the role of the gut bacteria by investigating G.

Glucose consumption rate-dependent transcriptome profiling of Escherichia coli provides insight on performance as microbial factories.

Background: The modification of glucose import capacity is an engineering strategy that has been shown to improve the characteristics of Escherichia coli as a microbial factory. A reduction in glucose import capacity can have a positive effect on production strain performance, however, this is not always the case. In this study, E.

Control of phenotypic diversification based on serial cultivations on different carbon sources leads to improved bacterial xylanase production.

Thermobacillus xylanilyticus is a thermophilic and hemicellulolytic bacterium of interest for the production of thermostable hemicellulases. Enzymes' production by this bacterium is challenging, because the proliferation of a cheating subpopulation of cells during exponential growth impairs the production of xylanase after serial cultivations. Accordingly, a strategy of successive cultivations with cells transfers in stationary phase and the use of wheat bran and wheat straw as carbon sources were tested.

Coculture of and Based on Metabolic Cross-Feeding Modulates Lipopeptide Production.

Cocultures have been widely explored for their use in deciphering microbial interaction and its impact on the metabolisms of the interacting microorganisms. In this work, we investigate, in different liquid coculture conditions, the compatibility of two microorganisms with the potential for the biocontrol of plant diseases: the fungus IHEM5437 and the bacterium GA1 (a strong antifungal lipopeptide producing strain). While the overgrew the in a rich medium due to its antifungal lipopeptide production, a drastically different trend was observed in a medium in which a nitrogen nutritional dependency was imposed.

Competence shut-off by intracellular pheromone degradation in salivarius streptococci.

Competence for DNA transformation is a major strategy for bacterial adaptation and survival. Yet, this successful tactic is energy-consuming, shifts dramatically the metabolism, and transitory impairs the regular cell-cycle. In streptococci, complex regulatory pathways control competence deactivation to narrow its development to a sharp window of time, a process known as competence shut-off.

Exploiting Information and Control Theory for Directing Gene Expression in Cell Populations.

Microbial populations can adapt to adverse environmental conditions either by appropriately sensing and responding to the changes in their surroundings or by stochastically switching to an alternative phenotypic state. Recent data point out that these two strategies can be exhibited by the same cellular system, depending on the amplitude/frequency of the environmental perturbations and on the architecture of the genetic circuits involved in the adaptation process. Accordingly, several mitigation strategies have been designed for the effective control of microbial populations in different contexts, ranging from biomedicine to bioprocess engineering.

Monitoring Intracellular Metabolite Dynamics in during Industrially Relevant Famine Stimuli.

Carbon limitation is a common feeding strategy in bioprocesses to enable an efficient microbiological conversion of a substrate to a product. However, industrial settings inherently promote mixing insufficiencies, creating zones of famine conditions. Cells frequently traveling through such regions repeatedly experience substrate shortages and respond individually but often with a deteriorated production performance.

Combined utilization of metabolic inhibitors to prevent synergistic multi-species biofilm formation.

Biofilm is ubiquitous in industrial water systems, causing biofouling and leading to heat transfer efficiency decreases. In particular, multi-species living in biofilms could boost biomass production and enhance treatment resistance. In this study, a total of 37 bacterial strains were isolated from a cooling tower biofilm where acetic acid and propionic acid were detected as the main carbon sources.

Reducing phenotypic instabilities of a microbial population during continuous cultivation based on cell switching dynamics.

Predicting the fate of individual cells among a microbial population (i.e., growth and gene expression) remains a challenge, especially when this population is exposed to very dynamic environmental conditions, such as those encountered during continuous cultivation.

Semi-continuous production of xanthan in biofilm reactor using Xanthomonas campestris.

Semi-continuous production of xanthan gum using self-immobilized Xanthomonas campestris cells in biofilm reactors was studied. Fermentation was carried out using two different designs of biofilm reactor equipped with a) stainless-steel support (SSS) and b) polyethylene support (PES). Fermentation was performed in three cycles with refreshing the media at the beginning of each: cycle 1, 0-27 h; cycle 2, 27-54 h; and cycle 3, 54-78.

Deletion of the Pro-Protein Processing Protease Gene Results in a pH-Dependent Morphological Transition during Submerged Cultivations and Increases Cell Wall Chitin Content.

There is a growing interest in the use of post-fermentation mycelial waste to obtain cell wall chitin as an added-value product. In the pursuit to identify suitable production strains that can be used for post-fermentation cell wall harvesting, we turned to an strain in which the gene was deleted. Previous work has shown that the deletion of causes hyper-branching and thicker cell walls, traits that may be beneficial for the reduction in fermentation viscosity and lysis.

Raman Spectroscopy-Based Measurements of Single-Cell Phenotypic Diversity in Microbial Populations.

Microbial cells experience physiological changes due to environmental change, such as pH and temperature, the release of bactericidal agents, or nutrient limitation. This has been shown to affect community assembly and physiological processes (e.g.

The Lazarus Effect: Recovery of Productivity on Glycerol/Lactose Mixed Feed in Continuous Biomanufacturing.

Continuous cultivation with has several benefits compared to classical fed-batch cultivation. The economic benefits would be a stable process, which leads to time independent quality of the product, and hence ease the downstream process. However, continuous biomanufacturing with is known to exhibit a drop of productivity after about 4-5 days of cultivation depending on dilution rate.