Aged related human skin microbiome and mycobiome in Korean women.

We examined differences in the skin microbiome of two separate age groups to find key microbial and skin physiological indicators associated with aging. We recruited healthy Korean women 19-28 years old (Y-group) and 60-63 years old (O-group) and evaluated their cheek and forehead skin microbiome, including bacteria and fungi. The microbiome was significantly different by age group, with bacterial and fungal communities displaying higher alpha-diversity in the O-group than in the Y-group. We identified amplicon sequence variants affiliated with Cutibacterium and Lactobacillus and fungi Malassezia restricta as microbial biomarkers showing significant differences between the Y and O-group. There are more microbial communities and metabolic processes related to skin health in the Y-group than in the O-group, and there are more microbial interactions to increase the stability of the network structure of the skin. Skin physical metadata, including transepidermal water loss and sebum content, differed by two age groups. The crucial skin microbes, skin physical parameters, and microbial network found through this research will be useful key indicators in associating skin aging and skin microbiome research.

Inferences in microbial structural signatures of acne microbiome and mycobiome.

Acne vulgaris, commonly known as acne, is the most common skin disorder and a multifactorial disease of the sebaceous gland. Although the pathophysiology of acne is still unclear, bacterial and fungal factors are known to be involved in. This study aimed to investigate whether the microbiomes and mycobiomes of acne patients are distinct from those of healthy subjects and to identify the structural signatures of microbiomes related to acne vulgaris. A total of 33 Korean female subjects were recruited (Acne group, n = 17; Healthy group, n = 16), and microbiome samples were collected swabbing the forehead and right cheek. To characterize the fungal and bacterial communities, 16S rRNA V4-V5 and ITS1 region, respectively, were sequenced and analysed using Qiime2. There were no significant differences in alpha and beta diversities of microbiomes between the Acne and Healthy groups. In comparison with the ratio of Cutibacterium to Staphylococcus, the acne patients had higher abundance of Staphylococcus compared to Cutibacterium than the healthy individuals. In network analysis with the dominant microorganism amplicon sequence variants (ASV) (Cutibacterium, Staphylococcus, Malassezia globosa, and Malassezia restricta) Cutibacterium acnes was identified to have hostile interactions with Staphylococcus and Malassezia globosa. Accordingly, this results suggest an insight into the differences in the skin microbiome and mycobiome between acne patients and healthy controls and provide possible microorganism candidates that modulate the microbiomes associated to acne vulgaris.

Clinical and Microbiological Efficacy of Pyrophosphate Containing Toothpaste: A Double-Blinded Placebo-Controlled Randomized Clinical Trial.

(1) Background: Dental calculus works as a niche wherein pathogenic bacteria proliferate in the oral cavity. Previous studies revealed the anticalculus activity of pyrophosphates, however there was no clinical study that evaluated microbiome changes associated with calculus inhibition. Therefore, the aim of this randomized clinical trial was to evaluate the calculus inhibition of pyrophosphate-containing toothpaste and its effect on oral microbiome changes. (2) Methods: Eighty subjects with a calculus index ≥2 on the lingual of the mandibular anterior tooth were randomly allocated to the test group that pyrophosphate-containing toothpaste was given to or the placebo control group. Full mouth debridement and standardized tooth brushing instruction were given before the allocation. Plaque index, gingival index, calculus index, probing depth, and bleeding on probing were measured at the baseline, and at 4, 8 and 12 weeks. Genomic DNA was extracted from the plaque samples collected at the baseline and at 12 weeks, and 16S ribosomal RNA gene amplicon sequencing was applied for microbiome analysis. (3) Results: None of the clinical parameters showed significant differences by visits or groups, except the plaque index of the test group, which reduced significantly between 4 and 12 weeks. A significant difference of microbiome between the baseline and 12 weeks was observed in the test group. Between baseline and 12 weeks, the proportion of Spirochetes decreased in the control group, and the proportions of Proteobacteria, Fusobacteria and Spirochetes in the phylum level and the proportions of Haemophilus, Fusobacterium and Capnocytophaga in the genus level decreased in the test group. In the test group, as plaque index decreased, Streptococcus increased, and Fusobacterium and Haemophilus parainfluenza decreased. (4) Conclusion: The use of pyrophosphate-containing toothpaste effectively inhibited the dysbiosis of the oral microbiome and the proliferation of pathogenic species in periodontal disease. Clinically, plaque formation in the pyrophosphate-containing toothpaste group was effectively decreased, however there was no significant change in calculus deposition.

Structures of the Skin Microbiome and Mycobiome Depending on Skin Sensitivity.

Sensitive skin (SS) syndrome is a globally widespread, self-diagnosed discomfort characterized by subjective complaints. Although the skin microbiome is considered important in skin health, the relationship between the skin microbiome and skin sensitivity is still unknown. Here, we aimed to (i) investigate whether the microbiome and mycobiome of SS are distinct from those of non-sensitive skin (NS), and (ii) define the characteristics of the skin microbiome associated with skin sensitivity. A total of 42 Korean women subjects were recruited (SS, n = 23; NS, n = 19) and the microbiome/mycobiome of their right facial cheeks were analyzed. We identified the differential microbiome and mycobiome structures between SS and NS. The mycobiome of SS was more phylogenetically diverse than that of NS. Lactobacillus and Mucor racemosus were more abundant on SS than NS, whereas Malassezia restricta was less abundant. Interestingly, both skin microbiome and mycobiome varied according to the perceived skin sensitivities of the subjects. This study suggests that the skin microbiome and mycobiome are associated with skin sensitivity. Accordingly, it lays the foundation for developing microbiome-based cosmetics or remedies for individuals suffering from SS syndrome.

Segregation of age-related skin microbiome characteristics by functionality.

Although physiological changes are the most evident indicators of skin aging by alteration of the skin's structure and function, we question whether skin aging is also affected by the structure and assembly process of the skin microbiome. We analysed the skin microbiomes of 73 healthy Chinese women in two age groups (25-35 years old and 56-63 years old) using 16S rRNA gene amplicon sequencing; the overall microbiome structure was significantly different between the two age groups. An analysis using ecological theory to evaluate the process of microbial community assembly processes revealed that the microbiomes of the older group were formed under a greater influence of the niche-based process, with the network of microbes being more collapsed than that of the younger group. Inferred metagenomic functional pathways associated with replication and repair were relatively more predominant in the younger group whereas, among the various metabolism-related pathways, those associated with biodegradation were more predominant in the older group. Interestingly, we found two segregated sub-typing patterns in the younger group which were also observed in the skin microbiomes of young Chinese women living in four other cities in China. The results of our study highlights candidate microbes and functional pathways that are important for future research into preventing skin aging and which could lead to a comprehensive understanding of age-related skin microbiome characteristics.

Antifungal Mechanism of Action of Lauryl Betaine Against Skin-Associated Fungus Malassezia restricta.

Betaine derivatives are considered major ingredients of shampoos and are commonly used as antistatic and viscosity-increasing agents. Several studies have also suggested that betaine derivatives can be used as antimicrobial agents. However, the antifungal activity and mechanism of action of betaine derivatives have not yet been fully understood. In this study, we investigated the antifungal activity of six betaine derivatives against Malassezia restricta, which is the most frequently isolated fungus from the human skin and is implicated in the development of dandruff. We found that, among the six betaine derivatives, lauryl betaine showed the most potent antifungal activity. The mechanism of action of lauryl betaine was studied mainly using another phylogenetically close model fungal organism, Cryptococcus neoformans, because of a lack of available genetic manipulation and functional genomics tools for M. restricta. Our genome-wide reverse genetic screening method using the C. neoformans gene deletion mutant library showed that the mutants with mutations in genes for cell membrane synthesis and integrity, particularly ergosterol synthesis, are highly sensitive to lauryl betaine. Furthermore, transcriptome changes in both C. neoformans and M. restricta cells grown in the presence of lauryl betaine were analyzed and the results indicated that the compound mainly affected cell membrane synthesis, particularly ergosterol synthesis. Overall, our data demonstrated that lauryl betaine influences ergosterol synthesis in C. neoformans and that the compound exerts a similar mechanism of action on M. restricta.

Fragile skin microbiomes in megacities are assembled by a predominantly niche-based process.

Given the higher incidence of skin diseases in more urbanized populations and its association with the skin microbiome, we questioned how the skin microbiome differed depending on the degree of urbanization. Skin microbiomes of 231 healthy subjects in five large cities in China varied mainly with environment and socioeconomic status of the cities in question. The differences among microbiomes could be explained by the predominantly niche-based assembly of microbial communities, which was supported by a dominance test, ß-null deviation, and edge-length abundance distribution. Networks among microbes in larger cities were more fragile, which may contribute to the higher incidence of skin diseases in more urbanized environments. These results suggest that microbial ecological theory can provide a framework for understanding crucial health-associated features of the human microbiome.

Field Emission and Electrical Properties of Perovskite.

We investigate characteristic field emission properties of methyl ammonium mixed-halide perovskite (CH3NH3PbI3-xClx) and their current change under one laser pulse. To analyze these properties, we fabricated inverted-type mixed-halide perovskite solar cells which exhibit a device efficiency of 9.31% under A.M 1.5 condition. Under one laser pulse varying from 420 nm to 580 nm, perovskite layer considerably reacted from 420 nm to 440 nm and then gradually decreased in current. A turnon field of 5.56 V and a field enhancement factor of 3183 were obtained from one spin-coating perovskite layer and in eight times of perovskite spin-coating cycles, a turn-on field of 6.70 V and a field enhancement factor of 5110 were observed.

Photocurrent Enhancement of CdSe Quantum-Dot Sensitized Solar Cells Incorporating Single-Walled Carbon Nanotubes.

We demonstrate quantum-dot sensitized solar cells (QDSSCs) which have colloidal CdSe quantum dots (TOPO-CdSe) as a sensitizer onto mesoporous TiO2 photoanodes. CdS quantum-dot (QD) layer plays a role of buffer layer for direct adsorption of TOPO-CdSe. We incorporate single-walled carbon nanotubes with TiO2 photoanode of our QDSSCs to facilitate efficient charge transfer. Shortcircuit current densities (Jsc) of our QDSSCs are enhanced while other parameters are maintained. Furthermore, we apply inert N2 pressure onto our sensitized photoanodes and observe 44% of Jsc enhancement with respect to pristine sample. Consequently, light-harvesting efficiency of our QDSSCs are increased. Significant series resistance reduction is observed from electrochemical impedance spectroscopy, indicating better interface contact between TiO2 photoanode and TOPOCdSe QD sensitizer are achieved.

Collapse of human scalp microbiome network in dandruff and seborrhoeic dermatitis.

We investigate the relationship between scalp microbiota and dandruff/seborrhoeic dermatitis (D/SD), an unpleasant scalp disorder common in human populations. Bacterial and fungal community analyses on scalp of 102 Korean were performed by next-generation sequencing. Overall scalp microbiome composition significantly differed between normal and disease groups, and especially co-occurrence network of dominant members was breakdown in disease groups. These findings will provide novel insights into shifts of microbial community relevant to D/SD.

Staphylococcus aureus inhibits terminal differentiation of normal human keratinocytes by stimulating interleukin-6 secretion.

BACKGROUND: Staphylococcus aureus (S. aureus) is found on the skin of approximately 90% of patients with atopic dermatitis and approximately 20% of apparently healthy subjects. S. aureus induces keratinocytes and immune cells to secrete immunoregulatory factors that cause epidermal barrier dysfunction in atopic skin. OBJECTIVE: This study examined factors that cause epidermal permeability barrier dysfunction in skin colonized by S. aureus. METHODS: We examined the effect of S. aureus on keratinocyte differentiation in the stratum corneum (SC) of in vivo skin, normal human keratinocytes (NHKs) and a reconstructed human epidermis (RHE) model. The fold change in expression of the terminal differentiation markers and the level of secreted cytokines were investigated. RESULTS: The SC displayed decreased expression of keratin 10 (KRT 10). NHKs treated with S. aureus extracts increased expression of interleukin (IL)-6 and significantly reduced expression of the terminal differentiation markers KRT 1, KRT 10, loricrin (LOR), and filaggrin (FLG); however, the expression of basal layer markers (KRT 5, KRT 14) remained unchanged. Treatment of NHKs with an anti-IL-6 antibody in combination with IL-6 or the S. aureus extracts inhibited the decrease in KRT 10 mRNA or protein expression. After the RHEs were exposed to the S. aureus extracts, KRT 1 and KRT 10 protein levels decreased. CONCLUSIONS: These findings suggest that S. aureus inhibits the terminal differentiation of keratinocytes by stimulating IL-6 secretion.