Biology subjects

Joseph, K. M.

Publications and source records attributed to Joseph, K. M..

5 recordsLinked to original sources

bioRxiv2025

Maternal PFAS Transfer through Lactation: Dolphin Milk Reveals Routes of Early-Life Exposure

Per- and polyfluoroalkyl substances (PFAS) continue to increase in concentration and prevalence in the environment due to the creation of emerging PFAS and lack of breakdown of legacy compounds. PFAS are known to both bioaccumulate and biomagnify, therefore, species higher on the food chain, such as marine mammals, are highly exposed to these chemicals. Although studies suggest that considerable maternal transfer of persistent organic pollutants occurs via lactation, data is lacking on the temporal trends associated with PFAS exposure. Here, we utilized a set of dolphin breastmilk samples from an individual mother across a two-year lactation period to evaluate longitudinal trends in PFAS concentrations and profiles. Thirty-six PFAS were detected using a multidimensional platform combining liquid chromatography, ion mobility spectrometry, and mass spectrometry (LC-IMS-MS), and of these, 17 PFAS were detected continuously across the nursing window of 103-706 days. Quantitative analysis specifically showed concentrations of perfluorooctanesulfonic acid (PFOS) alone surpass weekly intake recommendations from the European Food Safety Authority and Food Standards Australia New Zealand by 1,000-fold but decreased slightly over time, possibly due to transfer from feedings. Non-targeted analysis also identified 13 additional compounds including two long-chained perfluorosulfonic acids not traditionally targeted, as well as the PFOS precursors, perfluoroethylcyclohexane sulfonate (PFECHS) and 2-(N-ethylperfluorooctanesulfonamido)ethyl phosphate (SAmPAP). This study therefore suggests that breastmilk is a major contributor to early-life PFAS exposure to mammals, particularly for long-chained PFAS. SYNOPSISHigh concentrations of PFAS in dolphin milk reflect bioaccumulation and biomagnification, highlighting their persistence and harm to aquatic ecosystems and breastfed offspring. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=110 SRC="FIGDIR/small/651903v1_ufig1.gif" ALT="Figure 1"> View larger version (37K): org.highwire.dtl.DTLVardef@ff681eorg.highwire.dtl.DTLVardef@cbf6corg.highwire.dtl.DTLVardef@eb789dorg.highwire.dtl.DTLVardef@13ba275_HPS_FORMAT_FIGEXP M_FIG C_FIG

biochemistry↗

bioRxiv2025

Reference Library for Suspect Non-targeted Screening of Environmental Toxicants Using Ion Mobility Spectrometry-Mass Spectrometry

As our health is affected by the xenobiotic chemicals we are exposed to, it is important to rapidly assess these molecules both in the environment and our bodies. Targeted analytical methods coupling either gas or liquid chromatography with mass spectrometry (GC-MS or LC-MS) are commonly utilized in current exposure assessments. While these methods are accepted as the gold standard for exposure analyses, they often require multiple sample preparation steps and more than 30 minutes per sample. This throughput limitation is a critical gap for exposure assessments and has resulted in an evolving interest in using ion mobility spectrometry and MS (IMS-MS) for non-targeted studies. IMS-MS is a unique technique due to its rapid analytical capabilities (millisecond scanning) and detection of a wide range of chemicals based on unique collision cross section (CCS) and mass-to-charge (m/z) values. To increase the availability of IMS-MS information for exposure studies, here we utilized drift tube IMS-MS to evaluate 4,685 xenobiotic chemical standards from the Environmental Protection Agency Toxicity Forecaster (ToxCast) program including pesticides, industrial chemicals, pharmaceuticals, consumer products, and per- and polyfluoroalkyl substances (PFAS). In the analyses, 3,993 [M+H]+, [M+Na]+, [M-H]- and [M+]+ ion types were observed with high confidence and reproducibility ([≤]1% error intra-laboratory and [≤]2% inter-laboratory) from 2,140 unique chemicals. These values were then assembled into an openly available multidimensional database and uploaded to PubChem to enable rapid IMS-MS suspect screening for a wide range of environmental contaminants, faster response time in environmental exposure assessments, and assessments of xenobiotic-disease connections.

ecology↗

bioRxiv2024

Fluorescence Shadow Imaging of Hypsibius exemplaris Reveals Morphological Differences Between Sucrose- and CaCl2-Induced Osmobiotes

Tardigrades are renowned for their ability to survive a wide array of environmental stressors. In particular, tardigrades can curl in on themselves while losing a significant proportion of their internal water content to form a structure referred to as a tun. In surviving varying conditions, tardigrades undergo distinct morphological transformations that could indicate different underlying mechanisms of stress sensing and tolerance specific to the stress condition. Presently, methods to effectively distinguish between morphological transformations, including between tuns induced by different stress conditions, are lacking. Herein, a new approach for discriminating between tardigrade morphological states is developed and utilized to compare sucrose- and CaCl2-induced tuns. A novel method of shadow imaging with confocal laser scanning microscopy enabled production of three-dimensional renderings of tardigrades in various physiological states resulting in tardigrade volume measurements. Combining these measurements with qualitative morphological analysis using scanning electron microscopy revealed that sucrose- and CaCl2-induced tuns have distinct morphologies, including differences in the amount of water expelled during tun formation. Further, varying the concentration of the applied stressor did not affect the amount of water lost, pointing towards water expulsion being a controlled process that is adapted to the specific stressors. Summary StatementA novel method for volume measurements of biological specimens was developed and paired with scanning electron microscopy to allow for morphological comparisons between tardigrade osmobiotes.

physiology↗

bioRxiv2023

Chemobiosis reveals tardigrade tun formation is dependent on reversible cysteine oxidation

Tardigrades, commonly known as waterbears, are eight-legged microscopic invertebrates renowned for their ability to withstand extreme stressors, including high osmotic pressure, freezing temperatures, and complete desiccation. Limb retraction and expelling their internal water stores results in the tun state, greatly increasing their ability to survive. Emergence from the tun state and/or activity regain follows stress removal, where resumption of life cycle occurs as if stasis never occurred. However, the mechanism(s) through which tardigrades initiate tun formation is yet to be uncovered. Herein, we use chemobiosis to demonstrate that tardigrade tun formation is mediated by reactive oxygen species (ROS). We further reveal that tuns are dependent on reversible cysteine oxidation, and that this reversible cysteine oxidation is facilitated by the release of intracellular reactive oxygen species (ROS). We provide the first empirical evidence of chemobiosis and map the initiation and survival of tardigrades via osmobiosis, chemobiosis, and cryobiosis. In vivo electron paramagnetic spectrometry suggests an intracellular release of reactive oxygen species following stress induction; when this release is quenched through the application of exogenous antioxidants, the tardigrades can no longer survive osmotic stress. Together, this work suggests a conserved dependence of reversible cysteine oxidation across distinct tardigrade cryptobioses.

biochemistry↗

bioRxiv2020

Inferring spatially transient gene expression pattern from spatial transcriptomic studies

Spatial transcriptomic is a technology to provide deep transcriptomic profiling by preserving the spatial organization. Here, we present a framework for SPAtial Transcriptomic Analysis (SPATA, https://themilolab.github.io/SPATA), to provide a comprehensive characterization of spatially resolved gene expression, regional adaptation of transcriptional programs and transient dynamics along spatial trajectories.

bioinformatics↗