Biology subjects

Poole, A.

Publications and source records attributed to Poole, A..

9 recordsLinked to original sources

bioRxiv2026

Recombinant Echis disintegrins reveal distinct inhibitory profiles on platelet aggregation and endothelial cell migration

Disintegrins are snake venom toxins that bind integrins and modulate platelet aggregation and cell migration. Isolation from venom often yields insufficient quantities for comprehensive study, making recombinant expression essential for detailed toxin characterisation. Here, we produced and characterised four disintegrins from Echis coloratus and Echis ocellatus in Escherichia coli. These homologous proteins contain distinct integrin-binding motifs: EcDis_RGD, EoDis_RGD, EcDis_KGD, and EcDis_VGD. Functional activities were evaluated using human platelet aggregation and endothelial cell scratch wound-healing assays. RGD-containing disintegrins exhibited the strongest inhibition of platelet aggregation, with EcDis_RGD showing the highest potency. The EcDis_KGD disintegrin inhibited platelet aggregation less potently, whereas EcDis_VGD showed no detectable activity in our assays. In endothelial cells, EcDis_RGD disintegrin markedly impaired cell migration, while EoDis_RGD displayed weaker anti-migratory activity. Neither KGD- nor VGD-containing disintegrins significantly affected wound closure. EoDis_RGD exhibited similar antiplatelet activity to the native, venom-purified disintegrin ocellatusin, validating our recombinant expression strategy. However, the corresponding PII-SVMP preparation displayed reduced inhibitory activity, consistent with incomplete generation of fully mature disintegrins species. Our findings demonstrate the importance of both integrin-binding motif identity and surrounding sequence context in determining disintegrin function, and support further use of recombinant toxins in toxinology and as therapeutic lead molecules.

biochemistry↗

bioRxiv2026

Blindness reveals that Heschl's gyrus folding is not altered by auditory experience

Heschls gyrus (HG), which contains the primary auditory cortex, shows marked individual variability in its folding pattern, ranging from a single gyrus to partial or complete duplication. Greater HG duplication has been reported in expert musicians, often interpreted as evidence that auditory experience can shape cortical morphology. However, these structural differences might alternatively indicate a bias for musical careers in individuals whose anatomical predispositions facilitate expertise. Here, we examined HG morphology in blind individuals--a population with extensive auditory experience but without selection based on auditory ability. T1-weighted MRI data from 100 human participants (48 females, 42 males, 10 unknown) across blind and sighted groups were analyzed. HG was manually defined in each hemisphere, and folding was measured using both categorical morphology classification and continuous surface-based metrics. Across all analyses, blindness did not increase HG folding. These results suggest that the morphology of HG is largely predetermined. Significance statementIncreased anatomical folding in the auditory cortex has been reported in professional musicians. Is this structural variability due to experience-dependent plasticity, or is it that individuals with increased anatomical folding are more likely to become musicians? We examined Heschls gyrus (HG), which contains the primary auditory cortex, in blind individuals who rely heavily on auditory input. Despite extensive auditory experience, blindness did not alter HG folding. This finding suggests that the morphology of HG is not strongly influenced by auditory experience.

neuroscience↗

bioRxiv2026

Cell-specific roles for the conserved Galpha chaperone RIC-8 in cilia biology

Primary cilia exhibit conserved organization and contain structural and functional domains of unique molecular composition. The inversin compartment (InvC), which is found in the proximal ciliary segment of a subset of vertebrate and invertebrate cell types, concentrates different classes of signaling molecules. Mutations in genes encoding resident proteins of the InvC manifest in ciliopathies, highlighting the importance of the InvC in cilia biology. We previously showed that a chaperone of G proteins RIC-8 localizes to the InvC of C. elegans channel cilia; however, the mechanisms that regulate RIC-8 targeting to this ciliary sub-domain or RIC-8 function in the InvC remain unknown. Here, we build on our prior work to demonstrate that RIC-8 becomes restricted to the InvC during larval development and show that, while the RVxP motif and intact transition zone are required for its proper intraciliary distribution, RIC-8 localization to the cilium depends on intraflagellar transport. Using the ASH neuron as a model, we establish that RIC-8 modulates chemosensory responses mediated by channel cilia. Finally, we show that human RIC8A and RIC8B proteins are required for ciliogenesis in RPE-1 cells. Collectively, our results define ciliary trafficking mechanisms and novel functions for a highly conserved signaling protein.

cell biology↗

bioRxiv2026

RNA Quality Control Enables Antibiotic Tolerance

The mechanisms underlying adaptation to antibiotic pressure within complex host environments remain incompletely understood. By experimentally evolving Streptococcus pneumoniae subjected to various antibiotics and immune states, we demonstrate populations adopting distinct adaptive strategies depending on specific selective context. General antibiotic stress drives convergent mutations in rny, encoding the RNA degradosome scaffold RNase Y, that exhibit broad-spectrum antibiotic tolerance and accelerated recovery. Single-cell transcriptomics revealed antibiotic-induced death is driven by transcriptional collapse, a catastrophic loss of RNA quantity and integrity. In contrast, rny mutants avert this via a bet-hedging strategy: a resilient minority maintains a baseline transcriptional profile, while a quiescent majority undergoes selective RNA degradation to preserve transcript fidelity. Upon stress removal, these populations execute a prioritized transcriptional ribosomal reboot, facilitating accelerated recovery. These findings identify RNA turnover as a tunable master regulator to survive combined pressures of antibiotics and immunity.

microbiology↗

bioRxiv2024

A digital DNA system reveals the superiority of unidirectional inheritance over 'Lamarckian' inheritance

In biology, changes to a DNA sequence can impact protein sequence but changes to protein sequence (phenotype) do not flow back into DNA (genotype). A system with bidirectional information flow (i.e. both translation and reverse translation) remains a theoretical possibility for an independent origin of life or an artificial biosystem, but the recent development of digital data storage in DNA does just this: changes made to a digital file can be written back into DNA, meaning changes to phenotype can be written back to genotype. To explore the evolutionary properties of such a system, we created an artificial system where synthetic DNA serves as genotype and music as phenotype. Audio can be output from a DNA sequence, then recorded and written to DNA as codons, enabling bidirectional information flow (DNA[->]music and music[->]DNA). Our results show that the mutation rate in a bidirectional system is much higher than for unidirectional information flow, and that, under reverse translation there is no mechanism for preservation of codon choice across generations. This has the effect of eliminating the impact of spontaneous synonymous mutations, a key the benefit of a redundant genetic code. As a result, non-synonymous mutations are the only DNA-level changes that are transmitted across generations, and, as non-synonymous mutation can emerge at both genotypic and phenotypic levels, these occur at a two-fold higher frequency than in a unidirectional system. Our system holds some practical insight. First, for DNA read/write systems, it may be wise to avoid designing systems with de novo reverse translation because the opportunities for mutation are higher; tracking genotype information from the preceding generation to guide this process may reduce error. Second, our system helps clarify how a Lamarckian biological system might operate. We conclude that, were a Lamarckian system of inheritance a feature of early genetic systems, it would likely have been short lived as the high frequency of mutation would risk driving the system to extinction. A system based on unidirectional information flow thus appears superior as there are fewer opportunities for mutational error.

evolutionary biology↗

bioRxiv2024

Temporal and anteriorly positioned mitotic zones drive asymmetric microtubule patterns needed for Left-Right Organizer development.

Cellular proliferation is vital for tissue development, including the Left-Right Organizer (LRO), a transient organ critical for establishing the vertebrate LR body plan. This study investigates cell redistribution and the role of specific progenitor cells in LRO formation, focusing on cell lineage and behavior. Using zebrafish as a model, we mapped all mitotic events in Kupffers Vesicle (KV), revealing an FGF-dependent, anteriorly enriched mitotic pattern. With a KV-specific fluorescent microtubule (MT) line, we observed that mitotic spindles align along the KVs longest axis until the rosette stage, spindles that form after spin, and are excluded from KV. Early aligned spindles assemble cytokinetic bridges that point MT bundles toward a tight junction where a rosette will initially form. Post-abscission, repurposed MT bundles remain targeted at the rosette center, facilitating actin recruitment. Additional cells, both cytokinetic and non-cytokinetic, are incorporated into the rosette, repurposing or assembling MT bundles before actin recruitment. These findings show that initial divisions are crucial for rosette assembly, MT patterning, and actin remodeling during KV development.

developmental biology↗

bioRxiv2021

Analysis of HIV Reservoirs in Cellular Conjugates from Peripheral Blood

Defining distinctive attributes of HIV-infected cells will inform development of HIV cure-directed therapies. Prior ex vivo studies of blood and tissue have suggested that some HIV-infected CD4 T cells are found in conjugates with other cell types. Here, we analyzed levels and sequences of HIV nucleic acids in sorted cellular conjugates from PBMC. Compared to single CD4 T cells, conjugates containing CD4 T cells showed no enrichment for HIV DNA or RNA. However, in several HIV controllers, HIV DNA sequences from sorted conjugates were enriched for sequences closely related to plasma viruses. In ART-treated people, although subgenomic HIV DNA sequences in sorted conjugates and single cells were genetically intermingled, intact proviruses were more frequent in whole blood cells than in magnetically-purified CD4 T cells. We conclude that some HIV-infected cells have attributes that predict preferential loss during sample processing, and that may also reflect vulnerability to therapeutic targeting in vivo.

immunology↗

bioRxiv2018

Engineered Microbes to Sense and Respond to Enterotoxigenic Escherichia coli

Every year, Enterotoxigenic Escherichia coli (ETEC), the most common form of travelers diarrhea, affects thousands of military personnel deployed overseas. The goal of this research was to engineer non-pathogenic E. coli to sense ETEC, respond to its presence, and package the non-pathogenic E. coli in a cellulose matrix to enable environmental detection of ETEC. Two plasmids were created: sense-respond; and packaging. The sense-respond plasmid detected autoinducer 2 (AI-2), a quorum sensing molecule created by most ETEC strains, by expressing LsrR which switches on the Lsr promoter. Activation of the Lsr promoter expresses superfolder green fluorescent protein (sfGFP), indicating the presence of ETEC. The packaging plasmid expresses a fusion protein consisting of curli fibers and cellulose binding domains. These modified surface proteins permit the bacteria to bind to cellulose, encapsulating the sense-response module. This genetically engineered machine could be deployed in both the internal and external environment to detect ETEC.

synthetic biology↗

bioRxiv2017

Phosphatidylserine Exposure after Vascular Injury-Platelet or Endothelial

BackgroundPlatelets membranes are considered the paramount site for the assembly of tenase and prothrombinase complex and are key players in localising coagulation to wound sites. However, the endothelium is also known to express phosphatidylserine (PS) and support the binding of recombinant FVa/FXa even beyond the site of injury. It thus remains unclear, what cell type play the preeminent role in the cellular control of coagulation after vascular injury.\n\nApproachTo address this question, we utilised a model of haemostasis (full thickness 1mm excisional skin wounds) as well as tissues after injury in laser and ferric chloride models of thrombosis. Damage to the endothelium was assessed by the combined methods of picrosirius red staining, immunofluorescence and electron microscopy. Using multiphoton microscopy, we then compared the spatial distribution of PS on platelets and the endothelium.\n\nResultsPlatelets and detectable PS significantly co-localised compared with similar analysis of endothelial cell and exposed PS on wounded carotids arteries which was not significant. Point injury by laser induced restricted damage of the endothelium which was associated with limited platelets recruitment. In consistence with platelets response after FeCl3 injury, platelets exposed most of the PS detected at the wound edge where skin vessels were transected in our haemostasis model (Correlation Coeff. 0.78 +/- 0.12 vs 0.35 +/- 0.23).\n\nConclusionsWe surmised that data from the different models support a paradigm of graded haemostatic response to vascular injury, in which full platelets response is limited to wound sites exposing the sub-endothelial matrix.

physiology↗