Biology subjects

Blakley, I. C.

Publications and source records attributed to Blakley, I. C..

4 recordsLinked to original sources

bioRxiv2026

Integrated analysis reveals strong reproducible signals within and across studies of the built environment

BackgroundBuilt environment microbiome studies have identified numerous factors that shape indoor microbiomes, yet the reproducibility of these findings across buildings, timepoints, and research groups remains unclear. Differences in sequencing protocols, sampling design, and environments pose major challenges for cross-study comparisons, particularly in low-biomass environments where technical variation can obscure biological signal. To address this gap, we constructed a simple ontology which groups samples into one of three categories: hand, hand-associated surfaces, and floor then applied it to four publicly available 16S rRNA gene datasets: a hospital, university dormitory, Air Force dormitory, and private residential houses. ResultsWe identified strong and reproducible separation between floors and surfaces with frequent human contact. We found that floors consistently harbored soil-associated taxa, including KD4-96, 67-14, Skermanella, and Sphingobacterium, whereas hands and hand-associated surfaces were enriched with skin-associated genera, such as Lawsonella and Cutibacterium. Within studies, these results were generally consistent across timepoints. Across studies, mixed-model PERMANOVA analysis revealed significant clustering by sample type, with modest effects of study, suggesting that biological signal outweighed differences in laboratory or sequencing methods. Leave-one-study-out random forest models achieved high AUCs for hand vs. floor comparisons (0.865 to 0.921), moderate AUCs for hand-associated vs. floor comparisons, and weaker performance for hand vs. hand-associated comparisons. Application of the batch-correction method DEBIAS-M did not improve effect sizes or classification performance, indicating that reproducible structure was already discernible without batch adjustment. ConclusionsDespite substantial temporal and environmental heterogeneity among studies, we found that the built environment microbiome has a reproducible bacterial signal. There was consistent enrichment of soil-derived taxa on floors and human-associated taxa on hands and hand-associated surfaces suggesting a stable microbiome despite differences in building type, occupancy, and methodology. These findings establish an important foundation for future studies, suggesting cross-study comparability, the accuracy of ecological inference, and the ability to support the development of predictive applications in indoor microbiome research.

microbiology↗

bioRxiv2026

Temporal stability and niche partitioning of bacterial communities in paired residential sink P-traps

Sink P-traps harbor microbial communities derived from environmental and human sources, yet longitudinal studies examining their stability and assembly dynamics remain limited. Here, we present, to our knowledge, the longest continuous characterization of bacteria collected from residential sink P-traps, with daily sampling over two months (n = 61 days). Samples were collected from paired sinks in a shared bathroom to identify dominant taxa, quantify temporal stability, and determine how occupant usage patterns influence community assembly. Using full-length 16S rRNA gene sequencing, we identified 3,865 unique taxa, with both sinks dominated by common sink-associated genera, including Pseudomonas, Citrobacter, Klebsiella, and Arcobacter. Despite sharing identical plumbing, environmental conditions, and cleaning regimes, the two sinks maintained distinct communities (p < 0.001). Temporal stability analyses revealed notable differences: Sink A (male; hand washing, toothbrushing, shaving) exhibited deterministic dynamics with low variability (CV = 4.9%), significant temporal autocorrelation (p = 0.001), and predictable trajectories, with time explaining 49.9% of community variation. In contrast, Sink B (female; hand washing, toothbrushing, face washing, mouthwash use) displayed stochastic dynamics with high volatility (CV = 26.5%), no significant autocorrelation (p = 0.53), and minimal temporal predictability. Differential abundance analysis revealed that Sink B was enriched in anaerobes, biofilm-forming taxa, oral microbiome associates, and preservative-resistant and lipid-degrading bacteria, while Sink A harbored a more aerobic, skin-associated community. These findings demonstrate that individual usage patterns (particularly exposure to biocidal agents) can alter P-trap community structure and temporal dynamics, with implications for microbial community prediction in residential and healthcare settings. ImportanceSink drains are increasingly recognized as reservoirs for antimicrobial-resistant pathogens, yet we lack fundamental knowledge about what drives bacterial community dynamics in these environments. By sampling paired residential sink P-traps daily for two months, we show that individual-specific behaviors, such as using products with a biocidal effect, can alter community composition from a stable, predictable state to one characterized by stochastic fluctuations. The sink exposed to mouthwash and face wash harbored more anaerobes, biofilm formers, and oral bacteria, suggesting that repeated exposure promotes disturbance-tolerant taxa rather than reducing bacterial colonization. These results provide a baseline ecological framework for understanding P-trap microbiomes and suggest that predictive monitoring of sink-associated pathogens might be feasible in stable environments but more difficult when there is variable antimicrobial exposure -- a finding directly relevant to hospital infection control.

microbiology↗

bioRxiv2022

An integrative analysis of the biological clock hypothesis in human gut microbiome

BackgroundWhile previous studies have explored the relationship between aging and the gut microbiome, it remains unclear how consistent and reproducible this association is across different cultures and groups. We performed an integrative analysis with 11 independent datasets from nine different countries to test the idea that the aging gut microbiome can be viewed as a biological clock, in which microbial changes associated with age are consistent and measurable across distinct datasets. ResultsAs expected, our Principal Coordinate Analysis found strong batch effects with study ID by far the strongest signal across datasets. Despite this large batch effect, we found a consistent signal across studies that was largely driven by sample size with only our larger cohorts showing taxa in common associated with age. Likewise, Shannon diversity and richness were not consistently associated with age across the 11 datasets, but some positive correlations with richness and host age were observed among the four largest cohorts. The taxon with the most potential as a biomarker for the aging human gut microbiome is genus Bifidobacterium, with significantly negative associations with host age in three out of the four datasets that had more than 200 samples. ConclusionThe driving force behind low reproducibility of association of age with the microbiome in previous studies appears to be inadequate sample size rather than structural differences in the microbial community based on cohort characteristics. Results from a power analysis suggest that future studies on the aging human gut microbiome consider on the order of 100-300 samples to consistently observe an age signal. With these larger sample sizes, parametric and non-parametric model yield broadly similar power.

bioinformatics↗

bioRxiv2018

Cytokinin treatment of rice induces minimal effect on differential splicing compared to splicing between tissues

Alternatively spliced genes produce multiple spliced isoforms, called transcript variants. In differential alternative splicing, the relative abundance of transcript variants differs across sample types. Differential alternative splicing is common in animal systems and influences cellular development in many processes, but its extent and significance is not as well known in plants. To investigate alternative splicing in plants, we examined rice seedling RNA-Seq data that included approximately 40 million sequence alignments per library, three libraries per sample type, and four sample types: roots and shoots, each treated with exogenous cytokinin delivered hydroponically, plus mock-treated controls. Cytokinin treatment triggered expression changes in thousands of genes, but had minimal effect on alternative splicing. However, there were many splicing differences between roots and shoots. Analysis of a similar (but less deeply sequenced) mRNA-Seq data set from Arabidopsis showed the same pattern. Quantitative fragment analysis of reverse transcriptase-PCR products made from newly prepared rice samples confirmed nine of ten differential splicing events between rice roots and shoots. In both the Arabidopsis and rice mRNA-Seq data sets, most genes annotated as alternatively spliced had small minor variant frequencies, i.e., the less frequently observed forms were supported by fewer than 20% of informative mRNA-Seq sequences. Of splicing choices where there was more abundant support for minor forms, most alternative splicing events were located within the protein-coding sequence and also maintained the annotated reading frame. A tool for visualizing protein annotations in the context of genomic sequence (ProtAnnot) together with a genome browser (Integrated Genome Browser) were used to visualize and assess effects of differential splicing on gene function. In general, differentially spliced regions coincided with conserved regions in the encoded proteins, indicating that differential alternative splicing is likely to affect protein function between root and shoot tissue in rice.

molecular biology↗