Biology subjects

Krsmanovic, S.

Publications and source records attributed to Krsmanovic, S..

3 recordsLinked to original sources

bioRxiv2024

Fine Tuning Genetic Circuits via Host Context and RBS Modulation

The choice of organism to host a genetic circuit - the chassis - is often defaulted to model organisms due to their amenability. The chassis-design space has therefore remained underexplored as an engineering variable. In this work, we explored the design space of a genetic toggle switch through variations in nine ribosome binding sites compositions and three host contexts, creating 27 circuit variants. Characterization of performance metrics in terms of toggle switch output and host growth dynamics unveils a spectrum of performance profiles from our circuit library. We find that changes in host-context causes large shifts in overall performance, while modulating ribosome binding sites leads to more incremental changes. We find that a combined ribosome binding site and host-context modulation approach can be used to fine tune the properties of a toggle switch according to user-defined specifications, such as towards greater signaling strength, inducer sensitivity or both. Other auxiliary properties, such as inducer tolerance, are also exclusively accessed through changes in host-context. We demonstrate here that exploration of the chassis-design space can offer significant value, reconceptualizing the chassis-organism as an important part in the synthetic biologists toolbox with important implications for the field of synthetic biology. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=139 SRC="FIGDIR/small/604438v1_ufig1.gif" ALT="Figure 1"> View larger version (50K): org.highwire.dtl.DTLVardef@1ff45d0org.highwire.dtl.DTLVardef@4060d7org.highwire.dtl.DTLVardef@95d5d8org.highwire.dtl.DTLVardef@10a98d5_HPS_FORMAT_FIGEXP M_FIG C_FIG

synthetic biology↗

bioRxiv2023

The bioreactor microbiome of mass cultivated marine diatoms for industrial carbon capture and utilization

Marine microalgae are a promising innovation platform for carbon capture and utilization (CCU) biotechnologies to mitigate industrial greenhouse gas emissions. However, industrial-scale cultivation of algal mono-cultures is challenging and often unscalable. Non-axenic microalgae in large semi-open photobioreactors lead to the co-cultivation of diverse microbial communities. There is limited knowledge about the "bioreactor ecology" involving microalgae interacting with the microbiome and its subsequent impact on process stability and productivity. In this study, we describe the semi-continuous industrial mass cultivation of the cold-adapted marine diatom, Porosira glacialis UiT201, by investigating the prokaryotic and microeukaryotic (phytoplankton and heterotrophic protist) communities. Data were collected in two consecutive time series experiments, representing the initiation and operation of an preindustrial scale CCU photobioreactor (300,000 liters). The first experiment experienced a culture "crash" of the focal strain after 39 days, while the second culture remained stable and "healthy" for 60 days. The results highlight that this mass cultivation system represents a unique industrial marine microbial ecosystem. The succession of the prokaryotic community was primarily driven by species replacement, indicating turnover due to selective bioreactor conditions and/or biological interactions. Nonetheless, the bioreactor consistently harbors a recurring and abundant core microbiome, suggesting that the closely associated bacterial community is influenced by microalgae-specific properties and can endure a dynamic and variable environment. The observed culture collapse of P. glacialis coincided with changes in the core microbiome structure and different environmental growth conditions compared to the stable and "healthy" experiment. These findings imply that cohabiting microbial taxa within industrial microalgae cultivation likely play a critical role in stabilizing the conversion of industrial CO2 into marine biomass, and changes in community structure serve as an indicator of process stability.

microbiology↗

bioRxiv2022

Microbial community dynamics during a harmful Chrysochromulina leadbeateri bloom

A harmful algae bloom occurred in late spring 2019 across multiple, interconnected fjords and bays in northern Norway. The event was caused by the haptophyte Chrysochromulina leadbeateri and led to severe fish mortality at several salmon aquaculture facilities. This study reports on the spatial and temporal succession dynamics of the holistic marine microbiome associated with this bloom by relating all detectable 18S and 16S rRNA gene ASVs to the relative abundance of the C. leadbeateri focal taxon. A k-medoids clustering enabled inferences on how the causative focal taxon co-bloomed with diverse groups of bacteria and microeukaryotes. These co-blooming patterns showed high temporal variability and were distinct between two geographically separated time series stations during the regional harmful algae bloom. The distinct blooming patterns observed with respect to each station were poorly connected to environmental conditions suggesting that other factors, such as biological interactions, may be at least as important in shaping the dynamics of this type of harmful algae bloom. A deeper understanding of microbiome succession patterns during these rare but destructive events will help guide future efforts to forecast deviations from the natural bloom cycles of the northern Norwegian coastal marine ecosystems that are home to intensive aquaculture activities.

microbiology↗