Biology subjects

Hwang, C. Y.

Publications and source records attributed to Hwang, C. Y..

4 recordsLinked to original sources

bioRxiv2026

Inhaled black carbon induces depressive-like behavior and enhances stress-related blood-brain molecular vulnerability in mice

Black carbon (BC), a combustion-derived component of fine particulate matter, has been linked to depressive symptoms, but controlled experimental evidence remains limited. We established a controlled BC inhalation model combined with chronic restraint stress (CRS) to determine whether inhaled BC alone induces depressive-like behavior and whether concurrent stress enhances behavioral and molecular vulnerability. Male C57BL/6J mice were assigned to Control, CRS, BC, or BC+CRS groups and exposed for 21 consecutive days, followed by behavioral testing and molecular analyses of plasma-depleted whole blood and stress-related brain regions. BC exposure alone induced depressive-like behavior, and the combined BC+CRS condition showed the most pronounced phenotype. These findings indicate that inhaled BC is sufficient to influence stress-relevant behavior and may heighten vulnerability under chronic stress. At the molecular level, BC shifted peripheral responses toward a stress- and inflammation-associated state with reduced plasticity-related signaling, whereas CRS preferentially engaged glucocorticoid-responsive regulation. Combined BC+CRS exposure further altered plasticity- and transcription-related regulatory programs in blood and stress-related brain regions, with prominent changes in the nucleus accumbens. These condition-dependent molecular patterns suggest that BC engages blood-brain stress-related pathways in a context- and region-specific manner. Together, these findings identify inhaled BC as a neurobehaviorally relevant environmental hazard.

neuroscience↗

bioRxiv2026

Who Formed All That Iron?: A Novel Antarctic Chemolithotroph Drives Iron Biomineralization

Iron mineralization has profoundly influenced Earths biogeochemical history1,2, yet the specific mechanisms underlying banded iron formation (BIF) remain unresolved3-5. Here we profile the microbiomes of Holocene sediments beneath the Larsen C Ice Shelf (LCIS), Antarctica6-8, through stratigraphic analysis of sedimentary ancient DNA combined with metagenomics. Distinct microbial phases aligned with glacial facies boundaries, with sub-ice shelf communities dominated by chemolithoautotrophs including an uncultured Thermodesulfovibrionia. This bacterium, visualized by fluorescence in situ hybridization and designated Candidatus Mariimomonas ferrooxydans (phylum Nitrospirota), emerged as a keystone taxon with high network centrality. Its genome encodes Cyc2, a fused porin-cytochrome outer membrane protein implicated in Fe(II) oxidation. Heterologous expression of Cyc2 in Escherichia coli confirmed its ability to catalyze iron oxidation, supporting iron precipitation under dark, anoxic conditions. These pristine LCIS sediments, unaltered since the last glacial maximum, provide a modern analogue for synglacial BIFs deposited during Neoproterozoic Snowball Earth events. Our findings deliver direct genomic and functional evidence for chemolithotrophic iron oxidation, challenge phototroph-centric models of BIF genesis, and highlight microbial iron cycling as a recurring force in Earths geochemical evolution. Beyond Earth, these insights inform interpretations of iron deposits on other planetary bodies.

microbiology↗

bioRxiv2021

Community-wide epigenetics provides novel perspectives on the ecology and evolution of marine microbiome

DNA methylation in prokaryotes is involved in many different cellular processes including cell cycle regulation and defense against viruses. To date, most prokaryotic methylation systems have been studied in culturable microorganisms, resulting in a limited understanding of DNA methylation from a microbial ecology perspective. Here, we analyze the distribution patterns of several microbial epigenetics marks in the ocean microbiome through genome-centric metagenomics across all domains of life. We show that overall, DNA methylation can readily be detected across dominant oceanic bacterial, archaeal, and viral populations, and microbial epigenetic changes correlate with population differentiation. Furthermore, our genome-wide epigenetic analysis of Pelagibacter suggests that GANTC, a DNA methyltransferase target motif, is related to the cell cycle and is affected by environmental conditions. Yet, the presence of this motif also partitions the phylogeny of the Pelagibacter phages, possibly hinting at a competitive co-evolutionary history and multiple effects of a single methylation mark. One-Sentence SummaryDNA methylation patterns are associated with ecological changes and virus-host dynamics in the marine microbiome.

microbiology↗

bioRxiv2021

Assessment of Agaricus bisporus Mushroom as Protective Agent Against Ultraviolet Exposure

Mushrooms are versatile materials with applications including but not limited to food, cosmetics, and pharmaceutical industries. In this work, the potential of the common button mushroom, Agaricus bisporus, as a protective agent against ultraviolet exposure was assessed. The assessment was done by investigating the radical scavenging activity, sun protecting capability, and tyrosinase inhibiting properties of Agaricus bisporus ethanolic extract. The extraction was carried out using absolute ethanol as its solvent at low to room temperatures. The bioactive components of the ethanolic extract were analysed for its phenolic and flavonoid contents quantitatively, while other phytochemical agents were analysed qualitatively. The Agaricus bisporus ethanolic extract was found exhibit varying degree of activity in all of the assessment. We found low radical scavenging ability with %RSA IC50 of [~]5456 g/mL, low to moderate sun protecting factor of [~]5.355 at 5000 ppm concentration, and high tyrosinase inhibition property with IC50 of [~]2 g/mL. The high tyrosinase inhibition property was found to correlate with relatively high total phenolic content of [~]1143 mg GAE/100g for Agaricus bisporus and the presence of terpenoid in the ethanolic extract.

biochemistry↗