Biology subjects

Franklin, K. A.

Publications and source records attributed to Franklin, K. A..

3 recordsLinked to original sources

bioRxiv2026

Ocular findings in Northern Gannets following an outbreak of high pathogenicity avian influenza (H5N1)

BackgroundDuring 2021-2022, high pathogenicity avian influenza (HPAI) caused mass mortality in wild birds across Europe, with Northern Gannets (Morus bassanus) among the most affected. Following the outbreak, unusual alterations in the species characteristic pale iris were observed in some individuals. MethodsOpportunistically captured gannets on Bass Rock (n=52), selected to represent a range of iris pigmentation, were examined. Slit-lamp biomicroscopy, indirect ophthalmoscopy, rebound tonometry and photography were performed. Iris pigmentation was classified as normal, mottled or black. Eleven birds underwent avian influenza virus (AIV) serology. Histopathology was performed on two eyes. ResultsAbnormal iris pigmentation was found in 74% of adult and immature gannets, with 61% affected bilaterally. Additional signs consistent with uveitis were present in 77% of affected birds. Iris pigmentation abnormalities were positively associated with AIV H5 seropositivity (Fishers exact test, P=0.018). Histopathology from affected eyes showed increased melanin deposition and disorganisation, including loss of a distinct anterior layer of melanocytic cells and hypertrophy of melanocytes within the iris stroma. LimitationsField conditions limited uniform lighting and concurrent serology. ConclusionsIris pigmentation changes were associated with prior HPAI exposure and frequently accompanied by signs of uveitis, suggesting iris alterations may indicate past infection and potential chronic sequelae.

physiology↗

bioRxiv2024

An engineered chromatin protein with enhanced preferential binding of H3K27me3 over H3K9me3

Histone post-translational modifications (PTMs) in chromatin modulate enhancer function, gene expression, and cellular differentiation. Pockets within chromatin reader-effector proteins bind specific histone PTMs, and have informed the design of artificial probes. Histone binding domains (HBDs) interact via multiple contacts that may support greater specificity than antibodies, but are difficult to study because of their weak affinities in vitro. We used a "Cell-Free Histone-Binding Immunoassay" (CHIA) where interactions between cell-free-expressed engineered HBD proteins and immobilized histone peptides are measured in an ELISA system. Previously reported K33E and Q9D variants of the chromobox 7 (CBX7) HBD bound with high affinity to both H3K27me3 and H3K9me3. However in CBX8, the K33E substitution enhanced binding to K27me3 with minimal K9me3 binding. Furthermore, hydrophobic substitutions in the CBX8 hydrophobic clasp (V10, L49) supported affinity and specificity for K27me3. We demonstrate the utility of a new CBX8 variant as a H3K27me3-specific live cell chromatin probe.

synthetic biology↗

bioRxiv2024

Integration of light quality signals regulates ABA abundance and stomatal movements during seedling establishment

Obtaining sufficient light for photosynthesis and avoiding desiccation are two key challenges faced by seedlings during early establishment. Perception of light quality via specialised photoreceptors signals the availability of sunlight for photosynthesis. Canopy shade is depleted in red (R) and enriched in far-red (FR) light, lowering R:FR ratio, while direct sunlight and sunflecks contain UV-B. The balance of these wavelengths can determine the developmental strategy adopted by seedlings to either avoid shade, via stem elongation, or promote the expansion of photosynthetic organs. How seedlings regulate stomatal movements in different light environments is poorly understood. Using FR and UV-B supplementation to mimic aspects of canopy shade and sunlight respectively, we monitored stomatal apertures in Arabidopsis thaliana cotyledons. We show that low R:FR inhibits stomatal opening via a mechanism involving PHYTOCHROME INTERACTING FACTOR 4 (PIF4) and increased abscisic acid (ABA). In contrast, UV-B perceived by the UV RESISTANCE LOCUS 8 (UVR8) photoreceptor antagonises this response to promote stomatal opening in a response requiring phototropin photoreceptors. The convergence of phytochrome and UVR8 signalling to control ABA abundance enables plants to coordinate stem elongation and water use during seedling establishment in dynamic light environments.

plant biology↗