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Revisiting giant virus-host dynamics in brown algae: old stories and new perspectives
No full textThe recent discovery of widespread giant virus sequences integrated into the genomes of diverse eukaryotes, and in particular marine lineages, has reignited interest in the molecular mechanisms underlying giant virus-host interactions. The brown alga Ectocarpus represents a compelling and historically rich model for such studies. As early as the 1970s, it was used to investigate latent infections by giant double-stranded DNA viruses, with elegant classical genetics and electron microscopy approaches revealing key aspects of virus-host life cycle coordination. However, progress was limited by the lack of molecular and genomic tools. In this review, we revisit these foundational studies through the lens of recent technological advances, including the development of genetic and genomic resources for brown algae. These tools now enable mechanistic insights into giant viral integration, latency, activation and host response. We highlight how Ectocarpus and related systems can illuminate both the evolutionary and ecological dimensions of virus-host dynamics, with a particular emphasis on the molecular and genetic mechanisms that mediate these complex interactions
Dietary fat disrupts a commensal-host lipid network that promotes metabolic health
No full textThe microbiota influences metabolic health; however, few specific microbial molecules and mechanisms have been identified. We isolated a Turicibacter strain from a community of spore-forming bacteria that promotes leanness in mice. Human metagenomic analysis demonstrates reduced Turicibacter abundance in individuals with obesity. Similarly, a high-fat diet reduces Turicibacter colonization, preventing its weight-suppressive effects, which can be overcome with continuous Turicibacter supplementation. Ceramides accumulate during a high-fat diet and promote weight gain. Transcriptomics and lipidomics reveal that the spore-forming community and Turicibacter suppress host ceramides. Turicibacter produces unique lipids, which are reduced during a high-fat diet. These lipids can be transferred to host epithelial cells, reduce ceramide production, and decrease fat uptake. Treatment of animals with purified Turicibacter lipids prevents obesity, demonstrating that bacterial lipids can promote host metabolic health. These data identify a lipid metabolic circuit between bacteria and host that is disrupted by diet and can be targeted therapeutically
Accumulation of Trehalose 6-Phosphate in Candidozyma auris results in Decreased Echinocandin Resistance and Tolerance
No full textCandidozyma auris is an emerging multidrug-resistant fungal pathogen that poses a major public-health challenge owing to high mortality and the limited efficacy of current therapies. Echinocandins, which inhibit β-glucan synthesis, are first-line therapy for invasive C. auris infection; however, resistance to this class is rising, underscoring the urgent need for new antifungal targets. Here we show that enzymes in the trehalose-biosynthetic pathway regulate stress responses, antifungal resistance/tolerance and virulence in C. auris. The tps2Δ strain displays heightened susceptibility to echinocandins, whereas tps1Δ and tps1Δ tps2Δ strains show resistance and tolerance comparable to wild type (WT). Mechanistically, the tps2Δ strain accumulates trehalose 6-phosphate (T6P), which inhibits hexokinase activity and reduces the flux of glucose 6-phosphate (G6P) into the chitin biosynthesis pathway, leading to substantially decreased cell wall chitin. During echinocandin exposure, the tps2Δ strain fails to compensate for reduced β-glucan with increased chitin, thereby rendering it highly susceptible to these drugs. In a systemic mouse infection model, deletion of the TPS2 gene results in lower tissue fungal burdens after treatment with caspofungin. Together, these findings identify Tps2 as a potential therapeutic target that can potentiate echinocandin efficacy in C. auris via a distinct mechanism of action
Relationships between light exposure and aspects of cognitive function in everyday life
No full textLight exposure can modulate cognitive function, yet its effects outside of controlled laboratory settings remain insufficiently explored. To examine the relationship between real-world light exposure and cognitive performance, we assessed personal light exposure and measured subjective sleepiness, vigilance, working memory, and visual search performance over 7 days of daily life, in a convenience sample of UK adults (n = 58) without significant circadian challenge (shiftwork or jet-lag). A subset of participants (n = 41) attended an in-lab session comprising a battery of pupillometric and psychophysical tests aimed to quantify melanopsin-driven visual responses. We find significant associations between recent light exposure and subjective sleepiness. Recent light exposure was also associated with reaction times for both psychomotor vigilance and working memory tasks. In addition, higher daytime light exposure and an exposure pattern with reduced fragmentation were linked to improved cognitive performance across visual search, psychomotor vigilance, and working memory tasks. Higher daytime light exposure and earlier estimated bedtimes were associated with stronger relationships between recent light exposure and subjective sleepiness. These results provide real world support for the notion that intra- and inter-individual differences in light exposure meaningfully influence aspects of cognition, with beneficial effects of short-term bright light and of habitual light exposure patterns characterized by brighter daytimes, earlier rest phase, and greater intra- and inter-daily stability
Biomineralization-driven one-pot separation and stabilization of extracellular lipases bypassing purification
No full textThe industrial applications of enzymes are often hindered by labor-intensive purification and immobilization processes, which reduce enzyme activity and limit scalability. To overcome these limitations, we developed a one-pot calcium-based biomineralization strategy that enables the direct separation and immobilization of extracellular lipases secreted by Magnusiomyces sp. LA-1, without prior purification. During the biomimetic process, in situ precipitation of calcium carbonate microbeads entrapped secreted lipases (CaCO3@MLALPs) under mild aqueous conditions, maintaining their native conformation and catalytic functionality. The biomineralized lipases exhibited approximately seven-fold higher hydrolytic activity and 1.6-fold greater esterification efficiency than the purified enzyme, indicating that the mineral matrix provided both structural rigidity and molecular stabilization. The CaCO3@MLALPs retained 46 % of their activity after nine reuse cycles and 40 % after 100 d of storage, demonstrating excellent long-term durability and reusability. Under the esterification conditions, a glyceryl caprylate yield of 253 mM was achieved, confirming its practical potential in synthetic bioprocesses. Overall, this study developed a cost-effective and sustainable biomineralization platform for the direct recovery of extracellular enzymes, highlighting a purification-free and scalable approach to enzyme immobilization with enhanced stability and catalytic performance
