Biology subjects

Leung, K. S.

Publications and source records attributed to Leung, K. S..

3 recordsLinked to original sources

bioRxiv2025

Associations Between Gut Microbiome and 24-Hour Blood Pressure Variability: A Cross-sectional Study Highlighting Sex Differences and Potential Therapeutic Targets

Blood pressure (BP) variability is an independent risk factor for cardiovascular disease (CVD). While gut microbiota (GM) and GM-derived short-chain fatty acids (SCFAs) are recognized to play a key role in BP regulation, their association with BP variability remains poorly understood. This cross-sectional study of 241 community-dwelling individuals from Hong Kong (113 men and 128 women, mean age 54{+/-}6 years) without symptomatic CVD examined the associations of GM, characterized by shotgun sequencing, and plasma SCFAs, with systolic and diastolic blood pressure (SBP/DBP) variability assessed by 24-hour BP monitoring. GM analyses, using covariate-adjusted statistical models, revealed that higher 24-hour SBP CoV associated negatively with GM -diversity (Shannon and Simpsons index, P<0.05) and positively with Firmicutes/Bacteroidetes ratio, driven by the female cohort. Parabacteroides merdae, Bacteroides dorei, Bifidobacterium pseudocatenulatum, Alistipes finegoldii and Bacteroides intestinalis were negatively associated with indices of SBP/DBP variability in a sex-specific manner. Further analysis indicated that B. dorei may mediate SBP CoV via plasma iso-butyric acid in women (bootstrapping 95% CI: -3.6 to -0.19; P<0.05). We demonstrated that higher SBP variability is associated with markers of gut dysbiosis and a reduction in beneficial gut bacteria, particularly in women. Notably, we identified several gut bacterial species with potential therapeutic implications for managing 24-hour SBP/DBP variability, warranting further investigation.

microbiology↗

bioRxiv2025

Combinatorial protein barcodes enable self-correcting neuron tracing with nanoscale molecular context

Mapping nanoscale neuronal morphology with molecular annotations is critical for understanding healthy and dysfunctional brain circuits. Current methods are constrained by image segmentation errors and by sample defects (e.g., signal gaps, section loss). Genetic strategies promise to overcome these challenges by using easily distinguishable cell identity labels. However, multicolor approaches are spectrally limited in diversity, whereas nucleic acid barcoding lacks a cellfilling morphology signal for segmentation. Here, we introduce PRISM (Protein-barcode Reconstruction via Iterative Staining with Molecular annotations), a platform that integrates combinatorial delivery of antigenically distinct, cell-filling proteins with tissue expansion, multi-cycle imaging, barcode-augmented reconstruction, and molecular annotation. Protein barcodes increase label diversity by >750-fold over multicolor labeling and enable morphology reconstruction with intrinsic error correction. We acquired a [~]10 million {micro}m3 volume of mouse hippocampal area CA2/3, multiplexed across 23 barcode antigen and synaptic marker channels. By combining barcodes with shape information, we achieve an 8x increase in automatic tracing accuracy of genetically labelled neurons. We demonstrate PRISM supports automatic proofreading across micron-scale spatial gaps and reconnects neurites across discontinuities spanning hundreds of microns. Using PRISMs molecular annotation capability, we map the distribution of synapses onto traced neural morphology, characterizing challenging synaptic structures such as thorny excrescences (TEs), and discovering a size correlation among spatially proximal TEs on the same dendrite. PRISM thus supports selfcorrecting neuron reconstruction with molecular context.

neuroscience↗

bioRxiv2023

Structural stability of the oyster gut microbiome contributes to the host's physiological tolerance to temperature fluctuations on tropical rocky shores

Extreme high thermal conditions on tropical rocky shores are challenging to the survival of intertidal ectotherms. Yet, many species are highly successful in these environments in part due to their ability to regulate intrinsic mechanisms associated with physiological stress and their metabolic demand. More recently, there has been a growing awareness that other extrinsic mechanisms, such as animal-associated microbial communities, can also influence the tolerance and survival of ectotherms under stressful conditions. However, the extent to which the intrinsic and extrinsic mechanisms are functionally linked as part of the overall adaptive response of intertidal animals to temperature change and stress is poorly understood. Here, we examined the dynamics and potential interactions of intrinsic and extrinsic mechanisms in the tropical high-supratidal oyster, Isognomon nucleus. We found that oysters modulate their internal biochemistry (oxidized PUFA products, including 5-F2t-IsoP, 10-F4t-NeuroP, 13-F4t-NeuroP, and 16-F1t-PhytoP) as part of their adaptive regulation to cope with physiological stress during periods of extreme high temperatures when emersed. However, while we detected variation in alpha diversity (ASV richness and Shannon diversity index), dominant microbial taxa and microbial functions across time, no association was found with the host biochemical profiles. The findings here suggest that the thermal condition within oysters can independently influence their intrinsic biochemical responses and extrinsic microbiome profiles. Together, these mechanisms may contribute to the thermal tolerance and survival of the oysters in the challenging conditions of the tropical high-supratidal zone.

microbiology↗