Biology subjects

Burns, N.

Publications and source records attributed to Burns, N..

4 recordsLinked to original sources

bioRxiv2026

Intrinsic antifungal activity of curli nanofibers expands the design space for programmable antimicrobial biomaterials

The rise of antifungal resistance and limited antifungal drug classes creates an urgent need for biomaterials with localized, programmable activity. Here, we engineered curli nanofibers displaying the antifungal peptide heliomicin and unexpectedly discovered that wild-type CsgA itself exhibits intrinsic antifungal activity against Candida albicans, reducing fungal viability by approximately 2 log units. Heliomicin fusion enhanced this activity to a 3.5-log fungicidal reduction while preserving nanofiber self-assembly, hydrogel formation, mechanical properties, and 3D printability. Mechanistic analyses linked enhanced activity to membrane disruption and expansion of the cationic surface of CsgA. Heliomicin-CsgA hydrogels further reduced fungal burden and suppressed hyphal development in an ex vivo porcine skin infection model. These findings reveal that extracellular protein nanofibers can harbor intrinsic biological activities that can be uncovered and enhanced through protein engineering, establishing a strategy for developing intrinsically bioactive, programmable biomaterials for localized therapeutic applications against fungal pathogens and potentially other microbial infections.

bioengineering↗

bioRxiv2024

Volumetric mesoscopic electrophysiology: a new imaging modality for the non-human primate

The primate brain is a densely interconnected organ whose function is best understood by recording from the entire structure in parallel, rather than parts of it in sequence. However, available methods either have limited temporal resolution (functional magnetic resonance imaging), limited spatial resolution (macroscopic electroencephalography), or a limited field of view (microscopic electrophysiology). To address this need, we developed a volumetric, mesoscopic recording approach (MePhys) by tessellating the volume of a monkey hemisphere with 992 electrode contacts that were distributed across 62 chronically implanted multi-electrode shafts. We showcase the scientific promise of MePhys by describing the functional interactions of local field potentials between the more than 300,000 simultaneously recorded pairs of electrodes. We find that a subanesthetic dose of ketamine -believed to mimic certain aspects of psychosis- can create a pronounced state of functional disconnection and prevent the formation of stable large-scale intrinsic states. We conclude that MePhys provides a new and fundamentally distinct window into brain function whose unique profile of strengths and weaknesses complements existing approaches in synergistic ways.

neuroscience↗

bioRxiv2023

Exposure to the aryl hydrocarbon receptor agonist dioxin disrupts formation of the muscle, nerves, and vasculature in the developing jaw

Human exposures to environmental pollutants can disrupt embryonic development and impact juvenile and adult health outcomes by adversely affecting cell and organ function. Notwithstanding, environmental contamination continues to increase because of industrial development, insufficient regulations, and the mobilization of pollutants due to extreme weather events. Dioxins are a class of structurally related persistent organic pollutants that are highly toxic, carcinogenic, and teratogenic. 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is the most potent dioxin compound and has been shown to induce toxic effects in developing organisms by activating the aryl hydrocarbon receptor (AHR), a ligand activated transcription factor targeted by multiple persistent organic pollutants. Contaminant-induced AHR activation results in malformations in the craniofacial cartilages and neurocranium; however, the mechanisms mediating these phenotypes are not entirely understood. In this study, we utilized the optically transparent zebrafish model to elucidate novel transcriptional and structural targets of embryonic TCDD exposure leading to craniofacial malformations. To this end, we exposed zebrafish embryos at 4 hours post fertilization (hpf) to TCDD and employed a mixed-methods approach utilizing immunohistochemistry staining, transgenic reporter lines, fixed and in vivo confocal imaging, and timelapse microscopy to determine the targets mediating TCDD-induced craniofacial phenotypes. Our data shows that embryonic TCDD exposure reduced jaw and pharyngeal arch Sox10+ chondrocytes and Tcf21+ pharyngeal mesoderm progenitors. Exposure to TCDD correspondingly led to a reduction in collagen type II deposition in Sox10+ domains. Embryonic TCDD exposure impaired development of tissues derived from or guided by Tcf21+ progenitors, namely: nerves, muscle, and vasculature. Specifically, TCDD exposure disrupted development of the hyoid and mandibular arch muscles, decreased neural innervation of the jaw, resulted in compression of cranial nerves V and VII, and led to jaw vasculature malformations. Collectively, these findings reveal novel transcriptional and structural targets of TCDD-induced toxicity, showcasing how contaminant exposures lead to congenital craniofacial malformations. HighlightsO_LIEmbryonic TCDD exposure diminishes Sox10+ craniofacial chondrocytes. C_LIO_LIFollowing TCDD exposure Col2a1 deposition is reduced in Sox10+ domains. C_LIO_LIExposure to TCDD decreases Tcf21+ progenitors and impairs muscle formation. C_LIO_LITCDD exposure leads to defects jaw innervation and cranial nerve establishment. C_LIO_LIEarly TCDD exposure results in vasculature malformations in the jaw. C_LI Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=91 SRC="FIGDIR/small/546117v1_ufig1.gif" ALT="Figure 1"> View larger version (21K): org.highwire.dtl.DTLVardef@b803c4org.highwire.dtl.DTLVardef@ff4483org.highwire.dtl.DTLVardef@eafa18org.highwire.dtl.DTLVardef@c97dba_HPS_FORMAT_FIGEXP M_FIG C_FIG

developmental biology↗

bioRxiv2018

Copy number variants in clinical WGS: deployment and interpretation for rare and undiagnosed disease

PurposeCurrent diagnostic testing for genetic disorders involves serial use of specialized assays spanning multiple technologies. In principle, whole genome sequencing (WGS) has the potential to detect all genomic mutation types on a single platform and workflow. Here we sought to evaluate copy number variant (CNV) calling as part of a clinically accredited WGS test.\n\nMethodsUsing a depth-based copy number caller we performed analytical validation of CNV calling on a reference panel of 17 samples, compared the sensitivity of WGS-based variants to those from a clinical microarray, and set a bound on precision using orthogonal technologies. We developed a protocol for family-based analysis, annotation, filtering, visualization of WGS based CNV calls, and deployed this across a clinical cohort of 79 rare and undiagnosed cases.\n\nResultsWe found that CNV calls from WGS are at least as sensitive as those from microarrays, while only creating a modest increase in the number of variants interpreted (~10 CNVs per case). We identified clinically significant CNVs in 15% of the first 79 cases analyzed. This pipeline also enabled identification of cases of uniparental disomy (UPD) and a 50% mosaic trisomy 14. Directed analysis of some CNVs enabled break-point level resolution of genomic rearrangements and phasing of de-novo CNVs.\n\nConclusionRobust identification of CNVs by WGS is possible within a clinical testing environment, and further developments will bring improvements in resolution of smaller and more complex CNVs.

genomics↗