Triterpenoids are natural products widely found in the plant kingdom and have various pharmacological effects such as anti-inflammatory, antioxidant and anti-tumour. However, the content of triterpenoids in medicinal plants is low, and it is difficult to purify and isolate them due to their complex structure. The efficient production of some triterpenoids in chassis organisms has been achieved by constructing a heterologous triterpenoid synthesis pathway in engineered strains such as yeast, modifying the key enzymes in the pathway, and adjusting the metabolism of yeast. Modification of key enzymes in the synthetic pathway is currently an effective strategy to enhance the heterologous synthesis of triterpenoids. This paper reviews the current research progress on the modification of key enzymes downstream in the synthetic pathway and the design of key enzymes around them to enhance triterpenoid production in five main areas: 1) increasing the supply of triterpenoid precursors; 2) inhibition of the natural sterol pathway; 3) fusion expression of related enzymes; 4) compartmentalisation of the metabolic pathway; and 5) tapping and enhancing the triterpenoid efflux pump. Finally, recent advances and applications of artificial intelligence (AI) in enzyme engineering and pathway design for triterpenoid biosynthesis are highlighted. Challenges and perspectives for further increasing the yield of triterpenoid synthesis in Saccharomyces cerevisiae are presented.

Recent advances in sequencing technologies, particularly long-read platforms, have substantially improved contiguity of bacterial genome assemblies and enabled the routine generation of near-complete or circular genomes. However, achieving a contiguous assembly does not necessarily guarantee accuracy. Assembly errors, including structural misassemblies, collapsed repeats, incorrect circularization, plasmid reconstruction errors, and nucleotide-level inaccuracies, remain prevalent and may lead to misleading biological interpretations if not properly identified. In this review, we provide a comprehensive overview of bacterial genome assembly from a validation-centered perspective and examine the underlying causes of draft genome formation and assembly uncertainty, highlighting the roles of repetitive genomic structures, platform-specific error profiles, and algorithmic limitations. We further emphasize that the central challenge in contemporary bacterial genomics is no longer simply to maximize assembly contiguity, but to determine whether apparently complete genomes are truly correct and sufficiently reliable for their intended downstream applications. We propose a practical decision-making framework that links sequencing strategy, assembly workflow, polishing, and validation rigor, and introduce a tiered confidence classification to guide the interpretation of genome assembly reliability. As bacterial genome sequencing becomes increasingly routine and large-scale, future efforts should prioritize accuracy, reproducibility, transparent reporting, and evidence-supported validation over completeness alone.

Skin aging increases transepidermal water loss (TEWL), reduces elasticity, and perturbs the skin microbiome. Adipose tissue-derived stem cell exosomes (ASCE) show regenerative potential; however, their clinical effects on skin physiology and microbiome remain unclear. We conducted a split-face, randomized controlled trial in 16 adults aged ≥ 40 years with visible facial aging. One facial side received ultrasound-assisted transdermal delivery of a human ASCE-containing solution (HACS), whereas the other side received normal saline, at two-week intervals for three sessions. Biophysical outcomes (TEWL, stratum corneum hydration, and elasticity parameters R2/R5/R7) were assessed at baseline and week 2, 4, and 8. Wrinkles, pigmentation, and sebum levels were quantified using Mark-Vu imaging, and the Physician’s Global Aesthetic Improvement Scale (PGAIS) and patient satisfaction assessment scores were recorded. Skin swabs from ten participants were subjected to 16S rRNA and ITS1 sequencing. HACS treatment significantly reduced TEWL (p = 0.006 at week 2; p = 0.009 at week 8) and increased hydration (p < 0.001 at all time points) with a significant increase in elasticity (R2/R5/R7 values, p < 0.001). Both the PGAIS and patient satisfaction scores were significantly higher on the experimental side. Bacterial α/β-diversity remained largely unchanged, and no bacterial taxa remained significantly associated with skin parameters after FDR correction. In contrast, several fungal taxa showed significant positive associations with skin parameters after FDR correction, detectable only on the HACS-treated side. No significant adverse events were observed. HACS improved barrier function, elasticity, and aesthetic outcomes, whereas microbiome analyses suggested a modest fungal response associated with treatment-related skin changes in aging skin.

Meiotic recombination is initiated by programmed DNA double-strand breaks (DSBs), which are subsequently processed to generate single-stranded DNA (ssDNA). Replication protein A (RPA), a heterotrimeric ssDNA-binding complex, plays essential roles in DNA replication, repair, and recombination; however, the specific functions of RPA in meiotic recombination progression and chromosome morphogenesis remain unclear. Here, we investigate the role of RPA in recombination and meiotic progression by conditionally depleting Rfa1, the large subunit of the RPA complex, using an auxin-inducible degron (AID) system in Saccharomyces cerevisiae. We show that Rfa1 depletion causes severe defects in meiotic recombination, including impaired DSB processing, defective chromosome axis assembly, compromised synaptonemal complex formation, and failure of ZMM-dependent crossover recombination. Notably, inhibition of Mek1 protein kinase activity, which bypasses the recombination checkpoint, does not rescue these defects in Rfa1-depleted cells. Together, these findings identify RPA as a key factor that stabilizes recombination intermediates and coordinates prophase I events with chromosome synapsis and crossover formation during meiosis.

Marine dinoflagellates are gaining attention as sustainable bioresource for polyunsaturated fatty acids (PUFAs), particularly omega-3 such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). In the present study, we analyzed the FAs and transcriptomic profiles of marine dinoflagellates Amphidinium carterae (D-044) and Prorocentrum minimum (D-127) to evaluate their potential as FAs producers. Gas chromatography-FA methyl ester (GC-FAME) analysis showed that A. carterae is a superior omega-3 producer, yielding a total FA content of 67.6 mg/g DW. DHA accounted for 26.7% of the total FAME profile, which is significantly higher than that of P. minimum (18.1 mg/g DW; DHA 13.1%). Gene Ontology (GO) annotation revealed genes related to FAs and lipid metabolism in A. carterae (1,217 genes) and in P. minimum (2,317 genes), which provide a molecular basis for dinoflagellates with high lipid productivity. Notably, three lipid droplet-associated hydrolase (LDAH) genes with diverse evolutionary origins were identified from A. carterae. These findings suggest a potential expansion of the genetic repertoire related to lipid storage and metabolism, highlighting A. carterae and LDAH as candidates for future biotechnological applications and microalgal metabolic engineering.

Postbiotics derived from lactic acid bacteria (LAB) have attracted growing interest as stable and potentially safer alternatives to probiotics for use in foods and health-related products. Comprehensive safety evaluation remains essential before their broader application. In this study, we assessed the safety profiles of RHT3201, a postbiotic preparation derived from Lacticaseibacillus rhamnosus IDCC 3201, through genomic, genotoxic, acute oral, and subchronic oral toxicity studies. Whole-genome analysis showed that IDCC 3201 lacks antimicrobial resistance genes and exhibits no hemolytic activity, supporting the genomic safety of the source strain. RHT3201 showed no genotoxic potential in either in vitro or in vivo assays, as evidenced by no structural or numerical chromosomal aberrations at concentrations up to 5,000 μg/ml in CHL/IU cells and no increase in micronucleated polychromatic erythrocytes, with no suppression of bone marrow erythropoiesis by oral administration of RHT3201 at doses up to 15,000 mg/kg/day using a mouse model. In rats, single oral doses of up to 15,000 mg/kg caused no mortality, treatment-related clinical signs, or gross pathological abnormalities, indicating an approximate lethal dose greater than 15,000 mg/kg. In a 90-day repeated-dose oral toxicity study, no adverse treatment-related effects were observed at doses up to 5,000 mg/kg/day. Mild liver and thyroid histopathological findings were considered adaptive and reversible. Accordingly, the no-observed-adverse-effect level was determined to be 5,000 mg/kg/day. Taken together, these findings support the safety of RHT3201 as a LAB-derived postbiotic ingredient.