Although countless gut microbiome studies on colitis using mouse models have been carried out, experiments with small sample sizes have encountered reproducibility limitations because of batch effects and statistical errors. In this study, dextran-sodium-sulfate-induced microbial dysbiosis index (DiMDI) was introduced as a reliable dysbiosis index that can be used to assess the state of microbial dysbiosis in DSS-induced mouse models. Meta-analysis of 189 datasets from 11 independent studies was performed to construct the DiMDI. Microbial dysbiosis biomarkers, Muribaculaceae, Alistipes, Turicibacter, and Bacteroides, were selected through four different feature selection methods and used to construct the DiMDI. This index demonstrated a high accuracy of 82.3% and showed strong robustness (88.9%) in the independent cohort. Therefore, DiMDI may be used as a standard for assessing microbial imbalance in DSS-induced mouse models and may contribute to the development of reliable colitis microbiome studies in mouse experiments.

Skin aging involves biomechanical changes like decreased elasticity, increased wrinkle formation, and altered barrier function. The skin microbiome significantly impacts this process. Here, we investigated the effects of decreased Cutibacterium acnes abundance and increase in other skin microorganisms on skin biomechanical properties in 60 healthy Koreans from Seoul, divided into younger (20–29 years) and older (60–75 years) groups. Metagenomic sequencing and skin assessments showed that the older group exhibited decreased C. acnes dominance and increased microbial diversity, correlating with reduced skin elasticity and increased wrinkles. In the younger age group, the enriched pathways included zeatin biosynthesis, distinct biotin metabolism pathways, and cofactor and vitamin metabolism in the younger age group, whereas pathways related to lipid metabolism, energy metabolism, and responses to environmental stressors, including UV damage and pollution, were enriched in the older group, according to functional analysis results. Network analysis indicated higher microbial connectivity in the younger group, suggesting a more stable community, whereas the older group’s community displayed higher modularity, indicating more independent and specialized clusters. This study enhances our understanding of the impact of skin microbiome changes on skin aging, particularly the anti-aging effects of C. acnes. Future research should focus on the physiological mechanisms of skin microbiota on skin aging and explore therapeutic potentials to enhance skin health.

Centella asiatica, a traditional herb, is widely recognized for its pharmacologically active components, such as asiaticoside, madecassoside, asiatic acid, and madecassic acid. These components render it a highly sought-after ingredient in various industries, including cosmetics and pharmaceuticals. This study aimed to enhance the production and activity of these pharmacological constituents of C. asiatica using the plant growth-promoting rhizobacterium Priestia megaterium HyangYak-01 during its cultivation. To achieve this goal, the researchers conducted field experiments, which revealed an increase in the production of pharmacologically active compounds in C. asiatica cultivated with a P. megaterium HyangYak-01 culture solution. Additionally, quadrupole time-of-flight mass spectrometry (Q-TOF MS) confirmed that the composition ratios of the C. asiatica extract treated with the P. megaterium HyangYak-01 culture solution differed from those of the untreated control and type strain-treated groups. Skin cell experiments indicated that the C. asiatica extract treated with the P. megaterium HyangYak-01 culture solution exhibited greater skin barrier improvement and less pronounced inflammatory responses than those from plants grown without the bacterial culture solution. This study demonstrates that microbial treatment during plant cultivation can beneficially influence the production of pharmacological constituents, suggesting a valuable approach toward enhancing the therapeutic properties of plants.

Cutibacterium acnes is a Gram-positive bacterium commonly found on human skin, particularly in sebaceous areas. While it is typically considered a commensal, specific strain types based on single locus sequence typing (SLST) have been associated with pathogenic conditions or healthy skin. Recently, SLST D1 strains, part of phylotype IA1, have received attention for their potential benefits related to skin health. However, their genetic characteristics remain underexplored. Therefore, the whole genome of C. acnes CN6, an SLST D1 strain isolated from the facial skin of a healthy individual, was sequenced to expand the understanding of SLST D1 strains and identify genomic features that may support skin health. The whole genome sequencing of C. acnes CN6 was conducted using MinION reads based on de novo assembly, revealing a single circular complete chromosome. With the length of 2,550,458 bp and G + C content of 60.04%, the genome contains 2,492 genes, including 2,433 CDSs, 9 rRNAs, 46 tRNAs, 4 ncRNAs, and 134 pseudo genes. Previously predicted virulence proteins of C. ances were detected in the genome. Genome comparation with 200 C. acnes strains isolated from healthy facial skin revealed SLST D1 strain-specific genes and a unique variant of the znuC gene in D1 strains.

Sihyun Park, GyuDae Lee, Ikwhan Kim, Yeongyu Jeong, and Jae-Ho Shin. Microbiol. Biotechnol. Lett. 2023;51:306-8. https://doi.org/10.48022/mbl.2307.07013

Heyndrickxia oleronia is a Gram-positive, rod-shaped bacterium originally isolated from termites but has gained clinical importance due to its association