Paenibacillus exopolysaccharide alleviates Malassezia-induced skin damage: Enhancing skin barrier function, regulating immune responses, and modulating microbiota.

Numerous studies have established a strong association between Malassezia and various skin disorders, including atopic dermatitis. Finding appropriate methods or medications to alleviate Malassezia-induced skin damage is of notable public interest. This study aimed to evaluate the therapeutic effect of the exopolysaccharide EPS1, produced by Paenibacillus polymyxa, on Malassezia restricta-induced skin damage. In vitro assays indicated that EPS1 reduced the expression of pro-inflammatory cytokine genes in TNF-α-induced HaCaT cells. In a murine model, EPS1 was found to mitigate clinical symptoms, reduce epidermal thickness and mast cell infiltration, improve skin barrier function, decrease pro-inflammatory cytokine levels associated with type 17 inflammation, enhance Tregs in the spleen, upregulate the transcription of Treg-related genes in skin lesions, and modulate the skin microbiota. This study is the first to report the alleviating effect of Paenibacillus exopolysaccharide on Malassezia-induced skin inflammation and its impact on the skin microbiota. These findings support the potential of Paenibacillus exopolysaccharides as consumer products and therapeutic agents for managing Malassezia-induced skin damage by improving skin barrier function, modulating immune responses, and influencing skin microbiota.

Noncovalent composites of meso-substituted A2B2-porphyrins and carbon nanotubes for enhanced electrocatalytic oxygen reduction.

Exploring highly active oxygen reduction electrocatalysts with low precious metals content is imperative but remains a considerable challenge. Herein, a series of heterobimetallic multi-walled carbon nanotubes (MWCNTs) electrocatalysts based on metal complexes are presented. These electrocatalysts feature diverse transition metals (M=Mn, Fe, Co, Ni) 5,15-bromophenyl-10, 20-methoxyphenyl porphyrin (MBMP) and tetrakis(triphenylphosphine)palladium (0) (Pd[P(Ph3)4]) anchored non-covalently on its surface. The resulting NiBMP-based MWCNTs with Pd[P(Ph3)4] (PdNiN4/MWCNTs) display outstanding electrocatalytic oxygen reduction activity (onset potential, 0.941 V; half wave potential, 0.830 V) and robust long-term durability in alkaline electrolyte. While in neutral condition, the MnBMP-based MWCNTs with Pd[P(Ph3)4] (PdMnN4/MWCNTs) are the most active heterobimetallic ORR catalyst and produce ultra-low concentration hydrogen peroxide (H2O2yield, 1.2%-1.3%). Synergistically tuning the ORR electrocatalytic activity and electron transfer pathway is achieved by the formation of NiBMP/MnBMP-Pd[P(Ph3)4] active sites. This work indicates such metalloporphyrin-Pd[P(Ph3)4] active sites on MWCNTs have significantly positive influence on electrocatalytic ORR systems and provides facile and mild strategy for designing highly efficient ORR electrocatalysts with ultra-low loading precious metal.

Biofilm: New insights in the biological control of fruits with Bacillus amyloliquefaciens B4.

Biofilms are sessile microbial communities growing on surfaces, which are encased in some self-produced extracellular material. Beneficial biofilm could be widely used in agriculture, food, medicine, environment and other fields. As an ideal biocontrol agent, Bacillus amyloliquefaciens B4 can form a strong biofilm under static conditions. In this study, we screened out metal compounds that enhanced or inhibited the biofilm formation ability of B4, established the relationship between the biofilm of B4 strain and its postharvest biocontrol effect, and explored the regulation of metal compounds on the biofilm formation. The results showed 0.5 mmol L-1 ferric chloride could enhance the biofilm formation and strengthen the antifungal effect of B4, indicating that there was a positive relationship between the growth of biofilm and its biocontrol effect. The enhanced biofilm had a certain biocontrol effect on different fruit, including peach, loquat, Kyoho grape and cherry tomato. Furthermore, the expression of degU and tasA was affected by metal ion treatment, which meant the genes might be essential for the biofilm formation of B4. Our findings suggested that biofilm of B. amyloliquefaciens played an essential role in the process of biocontrol and it might be a novel strategy for managing postharvest fruit decay.