Biology subjects

Ostrowski, A.

Publications and source records attributed to Ostrowski, A..

3 recordsLinked to original sources

bioRxiv2025

3D Bioprinted Cell-laden GrooveNeuroTube: A Multifunctional Platform for Ex Vivo Neural Cell Migration and Growth Studies

Extensive peripheral nerve injuries often lead to the loss of neurological function due to slow regeneration and limited recovery over large gaps. Current clinical interventions, such as nerve guidance conduits (NGCs), face challenges in creating biomimetic microenvironments that effectively support nerve repair. The developed GrooveNeuroTube is composed of hyaluronic acid methacrylate and gelatin methacrylate hydrogel, incorporating active agents (growth factors and antibacterial agents) encapsulated within an NGC conduit made of 3D-printed PCL grid fibers. In vitro studies showed that GrooveNeuroTube significantly promoted migration of dorsal root ganglion (DRG) neuronal cells, 3D bioprinted at the far ends of the conduit to imitate a proximal nerve injury as a novel ex vivo model. A long-term culture of up to 60 days was employed to better mimic in vivo conditions. This model tested the effects of pulsed electromagnetic field (PEMF) stimulation on neural tissue development. After 60 days, GrooveNeuroTube showed a 32% cell migration increase compared to the growth-factor-group and 105% compared to the no-growth-factor condition. These results confirm that the GrooveNeuroTube system can effectively support sustained neural cell migration and maturation over extended periods, proving a new technology for testing peripheral nerve injury ex vivo. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=77 SRC="FIGDIR/small/639097v2_ufig1.gif" ALT="Figure 1"> View larger version (30K): org.highwire.dtl.DTLVardef@14c7799org.highwire.dtl.DTLVardef@14011c3org.highwire.dtl.DTLVardef@14e5a79org.highwire.dtl.DTLVardef@115e281_HPS_FORMAT_FIGEXP M_FIG C_FIG The graphical abstract was created with BioRender.com.

bioengineering↗

bioRxiv2024

A widely-occurring family of pore-forming effectors broadens the impact of the Serratia Type VI secretion system

The ability to compete with diverse competitors is essential for bacteria to succeed in microbial communities. A widespread strategy for inter-bacterial competition is the delivery of antibacterial toxins, or effector proteins, directly into rival cells using the Type VI secretion system (T6SS). Whilst a large number of broad-spectrum enzymatic T6SS effectors have been described, relatively few which form pores in target cell membranes have been reported. Here, we describe a widely-occurring new family of T6SS-dependent pore-forming effectors, exemplified by Ssp4 of Serratia marcescens Db10. We show in vitro that Ssp4 forms regulated pores that have higher selectivity for cations and use molecular dynamics simulations to support a high resolution structural model of a tetrameric membrane pore formed by Ssp4. Notably, Ssp4 displays a distinct ion selectivity, phylogenetic distribution and impact on intoxicated cells compared with Ssp6, the other cation-selective pore-forming toxin delivered by the same T6SS. Ssp4 is also active against a wider range of target species than Ssp6, highlighting that T6SS effectors are not always broad-spectrum. Finally, use of Tn-seq to identify Ssp4-resistant mutants reveals that a mucA mutant of Pseudomonas fluorescens, which overproduces extracellular polysaccharide, provides resistance to T6SS attacks. We conclude that possession of two distinct T6SS-dependent pore-forming toxins may be a common strategy to ensure effective de-energisation of closely- and distantly-related competitors.

microbiology↗

bioRxiv2018

Towards an Ecological Trait-data Standard

O_LITrait-based approaches are widespread throughout ecological research, offering great potential for trait data to deliver general and mechanistic conclusions. Accordingly,a wealth of trait data is available for many organism groups, but, due to a lack of standardisation, these data come in heterogeneous formats.\nC_LIO_LIWe review current initiatives and infrastructures for standardising trait data and discuss the importance of standardisation for trait data hosted in distributed open-access repositories.\nC_LIO_LIIn order to facilitate the standardisation and harmonisation of distributed trait datasets, we propose a general and simple vocabulary as well as a simple data structure for storing and sharing ecological trait data.\nC_LIO_LIAdditionally, we provide an R-package that enables the transformation of any tabular dataset into the proposed format. This also allows trait datasets from heterogeneous sources to be harmonised and merged, thus facilitating data compilation for any particular research focus.\nC_LIO_LIWith these decentralised tools for trait-data harmonisation, we intend to facilitate the exchange and analysis of trait data within ecological research and enable global syntheses of traits across a wide range of taxa and ecosystems.\nC_LI

ecology↗