Biology subjects

Tas, H.

Publications and source records attributed to Tas, H..

3 recordsLinked to original sources

bioRxiv2020

FlowScatt: enabling volume-independent flow cytometry data by decoupling fluorescence from scattering

MotivationMeasuring fluorescence by flow cytometry is fundamental for characterising single-cell performance. While it is known that fluorescence and scattering values tend to positively correlate, the impact of cell volume on fluorescence is typically overlooked. This makes of fluorescence values alone an inaccurate measurement for high-precision characterisations. ResultsWe developed FlowScatt, an open-source software package that removes volume-dependency in the fluorescence channel. Using FlowScatt, flourescence values are re-calculated based on the unified volume per cell that arises from scattering decomposition. AvailabilityFlowScatt is openly available as a Python package on https://github.com/rstoof/FlowScatt. Experimental data for validation is available online. Contactangel.goni-moreno@newcastle.ac.uk

bioinformatics↗

bioRxiv2020

A standardized broad host range inverter package for genetic circuitry design in Gram-negative bacteria

Genetically encoded logic gates, especially inverters--NOT gates--are the building blocks for designing circuits, engineering biosensors or decision-making devices in synthetic biology. However, the repertoire of inverters readily available for different species is rather limited. In this work, a large whole of NOT gates that was shown to function previously in a specific strain of Escherichia coli, was recreated as broad host range (BHR) collection of constructs assembled in low, medium and high copy number plasmid backbones of the SEVA (Standard European Vector Architecture) collection. The input/output function of each of the gates was characterized and parameterized in the environmental bacterium and metabolic engineering chassis Pseudomonas putida. Comparisons of the resulting fluorescence cytometry data with those published for the same gates in Escherichia coli provided useful hints on the portability of the corresponding gates. The hereby described BHR inverter package (20 different versions of 12 distinct gates) thus becomes a toolbox of choice for designing genetic circuitries in a variety of Gram-negative species other than E. coli.

synthetic biology↗

bioRxiv2020

Contextual dependencies expand the re-usability of genetic inverters

The design and implementation of Boolean logic functions in living cells has become a very active field within synthetic biology. By controlling networks of regulatory proteins, novel genetic circuits are engineered to generate predefined output responses. Although many current implementations focus solely on the genetic components of the circuit, the host context in which the circuit performs is crucial for its outcome. Here, we characterise 20 genetic NOT logic gates (inverters) in up to 7 bacterial-based contexts each, to finally generate 135 different functions. The contexts we focus on are particular combinations of four plasmid backbones and three hosts, two Escherichia coli and one Pseudomonas putida strains. Each NOT logic gate shows seven different logic behaviours, depending on the context. That is, gates can be reconfigured to fit response requirements by changing only contextual parameters. Computational analysis shows that this range of behaviours improves the compatibility between gates, because there are considerably more possibilities for combination than when considering a unique function per genetic construct. Finally, we address the issue of interoperability and portability by measuring, scoring, and comparing gate performance across contexts. Rather than being a limitation, we argue that the effect of the genetic background on synthetic constructs expand the scope of the functions that can be engineered in complex cellular environments, and advocate for considering context as a fundamental design parameter for synthetic biology.

synthetic biology↗