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.

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.

New approach to the immobilization of glucose oxidase on non-porous silica microspheres functionalized by (3-aminopropyl)trimethoxysilane (APTMS).

The immobilization and encapsulation of glucose oxidase (GOD) onto the mesoporous and the non-porous silica spheres prepared by co-condensation of tetraethylorthosilicate (TEOS) and (3-aminopropyl)trimethoxysilane (APTMS) in the water-in-oil (W/O) emulsion system were studied. The terminal amine group was used as the important functionality for GOD immobilization on the silica substrate. When only TEOS is used as a silica source, the disordered mesoporous silica microspheres are obtained. As the molar ratio of APTMS to TEOS (R(AT)) increases, the surface area and pore volume of the silica particles measured by nitrogen adsorption and desorption method and SEM decrease rapidly. Particularly, the largest change of the surface morphology is observed between R(AT)=0.20 and R(AT)=0.25. The amount and the adsorption time of immobilized enzyme were measured by UV spectroscopy. About 20wt% of GOD was immobilized into the silica substrates above R(AT)=0.60 and was completely adsorbed into the substrate of R(AT)=0.80 with lapse of 4h after addition. In the measurement of the thermal stability, GOD dissolved in buffer solution loses nearly all of its activity after 30 min at 65 degrees C. In contrast, GOD immobilized on the surface-modified silica particles still retains about 90% of its activity after the same treatment. At this temperature, the immobilized glucose oxidase retained half of its initial activity after 4h. It is shown that the suitable usage of functionalizing agent like APTMS as well as the control of surface morphology is very important on the immobilization of enzyme.