Clinical effect of Pediococcus acidilactici PMC48 on hyperpigmented skin

BACKGROUND

The excessive production and accumulation of melanin in the epidermal skin layer can result in skin hyperpigmentation and darkening. Current technologies for regulating melanin are based on inhibiting melanin biosynthesis. They have low effectiveness and safety issues.

AIMS

This study aimed to evaluate the potential role of Pediococcus acidilactici PMC48 as a probiotic strain in medicines and cosmetics for skin treatment.

MATERIALS AND METHODS

Meanwhile, our research team has reported that P. acidilactici PMC48 strain isolated from sesame leaf kimchi can directly decompose the already synthesized melanin. It can also inhibit melanin biosynthesis. In the present study, we investigated the skin-whitening effect of this strain by arranging an 8-week clinical trial with 22 participants. PMC48 was applied to each participant's artificially UV-induced tanned skin in the clinical trial. Its whitening effect was investigated based on visual evaluation, skin brightness, and melanin index.

RESULTS

PMC48 showed a significant effect on the artificially induced pigmented skin. The color intensity of the tanned skin was decreased by 47.647%, and skin brightness was increased by 8.098% after the treatment period. PMC48 also significantly decreased the melanin index by 11.818%, indicating its tyrosinase inhibition capacity. Also, PMC48 improved skin moisture content level by 20.943%. Additionally, 16S rRNA-based amplicon sequencing analysis showed a distinct increase in Lactobacillaceae in the skin by up to 11.2% at the family level without affecting other skin microbiota. Furthermore, it showed no toxicity in in vitro or in vivo analyses.

DISCUSSION

These results indicate that P. acidilactici PMC48 is a promising probiotic strain that can be used to develop medicines and cosmetic products to solve skin-related problems.

CONCLUSIONS

These results demonstrate that P. acidilactici PMC48 can be a potential probiotic for the cosmetic industry against different skin disorders.

Screening and Constructing a Library of Promoter-5'-UTR Complexes with Gradient Strength in Pediococcus acidilactici

The GRAS (generally recognized as safe) strain Pediococcus acidilactici is well known for its antibacterial and probiotic functions. Furthermore, as P. acidilactici has excellent high temperature and salt resistance, it is an ideal host for the production of food enzymes, food additives, and pharmaceuticals. In this regard, it is desirable and feasible to enhance the production of these products through the metabolic engineering of P. acidilactici. However, the rare gene expression elements greatly obstruct the development of engineering P. acidilactici. In this study, we screened and constructed a library of promoter-5'-UTR (PUTR) complexes in P. acidilactici DY15 for regulating gene expression at the transcription and translation levels. In the post-log phase, the mRNA and protein expression level ranges of the 90 screened native PUTRs were 0.059-2010% and 0.77-245%, respectively, of the P32 promoter. Besides, several PUTRs exhibited great expression stability under high temperature, salt, and ethanol stress. We analyzed the structure of PUTRs and obtained the conserved regions of the promoter and 5'-UTR. Based on the identified core regions of PUTRs, we constructed a panel of combinatorial PUTRs with higher and stable protein expression levels. The strongest combinatorial PUTR was 853% of the P32 promoter in the protein expression level. Finally, the obtained PUTRs were applied to optimize the expression level of aminotransferase and improve the phenyllactic acid (PLA) production in P. acidilactici DY15. The achieved yield was 950.6 mg/L, which was 79.2% higher than the wild-type strain. These results indicated that the obtained PUTRs with gradient strength had great potential for precisely regulating gene expression to achieve various goals in P. acidilactici.

Proteomic Profiling and Stress Response in Pediococcus acidilactici under Acetic Acid

Lactic acid bacteria are indispensable functional microorganisms for cereal vinegar brewing, but cell activities are inhibited by the dominant acetic acid stress. Herein, an acetic-acid-tolerant strain isolated previously was identified as Pediococcus acidilactici, which also exhibited good resistance to other stresses during vinegar brewing. Proteomics analysis evidenced that differentially expressed proteins involved in the glycolysis and gluconeogenesis pathway, pyruvate metabolism, and sugar phosphotransferase system were all downregulated. Meanwhile, saturation of fatty acids and antioxidant enzymes was strengthened. The effects of several proteins on the resistance of P. acidilactici and Lactobacillus lactis relied on the types of strain and stress. AccA and AcpP participating in fatty acid metabolism and biosynthesis and Mnc related to stress response were found to protect cells by modifying fatty acid compositions and reinforcing the antioxidant defense system. Our works deepen the mechanisms of P. acidilactici under acetic acid and offer targets for engineering cell tolerance.

Inhibition of acetic acid-induced colitis in rats by new Pediococcus acidilactici strains, vitamin producers recovered from human gut microbiota

Our aim was to isolate, identify and characterize probiotic bacteria as vitamin producers in particular B2 and B9. 150 human fecal samples were collected and used for isolation of vitamin producers—probiotics. 49 isolates were chosen for screening their genome by PCR for the presence of riboflavin and folic acid genes. As a result, three isolates were selected and their production of the B2 and B9 were confirmed by HPLC. The three isolates were identified on species level by sequencing their 16S rRNA gene which showed 100% identical to strains of Pediococcus acidilactici. Thus, they were named as P. acidilactici WNYM01, P. acidilactici WNYM02, P. acidilactici WNYM03 and submitted to the Genbank database with accession numbers. They met the probiotic criteria by expressing 90–95% survival rate at pH (2.0–9.0) and bile salt up to 2% for 3 h in addition to their antimicrobial activity against gram positive and negative microorganisms. They also showed no hemolytic activity and common pattern for antibiotic susceptibility. Our three strains were tested individually or in mixture in vivo on rat colitis model compared to ulcerative group. The strains were administrated orally to rats in daily dose containing CFU 10⁹ for 14 days then followed by induction of colitis using acetic acid then the oral administration was continued for more four days. The histology results, the anti-inflammatory and anti-oxidative stress biomarkers showed the protective role of the strains compared to the ulcerative group. As a conclusion, we introduce novel three probiotic candidates for pharmaceutical preparations and health applications.

Comparative genomics analysis of Pediococcus acidilactici species

Pediococcus acidilactici is a reliable bacteriocin producer and a promising probiotic species with wide application in the food and health industry. However, the underlying genetic features of this species have not been analyzed. In this study, we performed a comprehensive comparative genomic analysis of 41 P. acidilactici strains from various ecological niches. The bacteriocin production of 41 strains were predicted and three kinds of bacteriocin encoding genes were identified in 11 P. acidilactici strains, namely pediocin PA-1, enterolysin A, and colicin-B. Moreover, whole-genome analysis showed a high genetic diversity within the population, mainly related to a large proportion of variable genomes, mobile elements, and hypothetical genes obtained through horizontal gene transfer. In addition, comparative genomics also facilitated the genetic explanation of the adaptation for host environment, which specify the protection mechanism against the invasion of foreign DNA (i.e. CRISPR/Cas locus), as well as carbohydrate fermentation. The 41 strains of P. acidilactici can metabolize a variety of carbon sources, which enhances the adaptability of this species and survival in different environments. This study evaluated the antibacterial ability, genome evolution, and ecological flexibility of P. acidilactici from the perspective of genetics and provides strong supporting evidence for its industrial development and application.

Increasing sodium lactate production by enhancement of Na+ transmembrane transportation in Pediococcus acidilactici

Fermentative production of sodium lactate generally is a low efficient process because of the high Na⁺ osmatic stress on lactic acid bacterium cells. In this study, the homogeneous genes encoding Na⁺/H⁺ antiporters were screened and overexpressed in Pediococcus acidilactici for the enhancement of Na⁺ transmembrane transportation. The function of the gene RS02775 was identified and its overexpressing in P. acidilactici resulted in the significantly improved sodium lactate production. The recombinant not only accelerated the sugar consumption, but also achieved the record high titer of sodium lactate by 121.1 g/L using pure sugars and 132.4 g/L using wheat straw. The transcription analysis shows that the overexpression of Na⁺/H⁺ antiporter significantly upregulated the transcription of the sugar phosphorylation genes of P. acidilactici under high Na⁺ stress. This study provides an effective method for high titer production of sodium lactate using both pure sugars and lignocellulose feedstocks.

Isolation and identification of an isoflavone reducing bacterium from feces from a pregnant horse

The aim of this research was to isolate bacteria capable of biotransforming daidzein from fresh feces from pregnant horses. A Hungate anaerobic roller tube was used for anaerobic culture. Single colonies were picked at random and incubated with daidzein. High performance liquid chromatography was used to detect whether the isolated bacteria were able to biotransform the substrate. A strain capable of reducing daidzein was selected and characterized using sequence analysis of 16S rDNA, and a phylogenetic tree was constructed. The morphological physiological and biochemical characteristics of the strain were investigated. A facultative anaerobic, Gram-positive bacterium capable of converting daidzein to dihydrodaidzein was isolated and named HXBM408 (MF992210). A BLAST search of HXBM408's 16S rDNA sequence against the GenBank database suggested that the strain has 99% similarity with Pediococcus acidilactici strain DSM (NR042057). The morphological, physiological, and biochemical characteristics of HXBM408 are very similar to those of Pediococcus. Based on these characteristics, the strain was identified as Pediococcus acidilactici. The bacterial strain HXBM408 isolated from the feces of pregnant horses was able to reduce the isoflavone daidzein to dihydrodaidzein.

Next generation sequencing, biochemical characterization, metabolic pathway analysis of novel probiotic Pediococcus acidilactici NCDC 252 and it's evolutionary relationship with other lactic acid bacteria

Pediococcus acidilactici NCDC 252 is a facultative anaerobe of dairy origin that possessed all studied in vitro probiotic attributes and several useful enzyme activities. Its whole genome was sequenced and analysed for its evolutionary relationship with other lactic acid bacteria (LAB). This is a novel sequence and first report of genome sequence of P. acidilactici of dairy origin. Its genome is relatively larger than other studied genomes of P. acidilactici and is comprised of 40 scaffolds that totals to 3,243,337 bases and 44.5% GC content. A total of 3054 coding sequences (CDS) were identified by RAST and DIAMOND servers. The genome also encoded different enzyme activities required for utilization of various carbohydrates. This was also confirmed by carbohydrate utilization studies. The genome also encoded genes for probiotics properties. The phylogenetic analysis of P. acidilactici NCDC 252 genome was done using Maximum Parsimony and Maximum Likelihood methods to study its evolution and relatedness to other LABs based upon their 16S rDNA sequences. The strain exhibited highest resemblance to Lactobacillus plantarum WCFS1 and is also much close to P. acidilactici based on similarity of ribosomal protein. The strain seems to have acquired some genes for its adaptation in dairy/environmental niche. This genome sequence is novel with genome more similar to L. plantarum and biochemical and phenotypic characteristics of P. acidilactici.

Transcriptomic Analysis of Xylan Oligosaccharide Utilization Systems in Pediococcus acidilactici Strain BCC-1

Xylan oligosaccharides (XOS) are the hydrolysates of xylan. To compare the proliferation effect of XOS, glucose, fructo oligosaccharides (FOS), xylose, XOS, and a media without carbohydrate source (control) on Pediococcus acidilactici strain BCC-1, the de novo sequencing of Pediococcus acidilactici strain BCC-1 was conducted, and the underlying mechanism of prebiotic xylo oligosaccharide between xylose and XOS was revealed through transcriptomic analysis. Compared to FOS, glucose, and xylose, XOS exhibits a good performance in promoting the fermentation of Pediococcus acidilactici BCC-1. The genome of Pediococcus acidilactici BCC-1 revealed genes encoding XOS transportation and utilized related enzymes, including ATP-binding cassette (ABC) transporters, arabinofuranosidase, xylanase, xylosidase, xylose isomerase, and xylulose kinase. Transcriptome analysis showed that XOS treatment enhanced genes involving carbohydrate metabolism, an ABC transporter sugar system, pentose and glucuronate interconversions, pyruvate metabolism, and the TCA process when compared to xylose treatment. It suggested XOS treatment enhanced sugar absorption and utilization. These results are useful in the understanding of the metabolic pathway of XOS in Pediococcus acidilactici BBC-1 and may contribute to the optimization of the probiotic effect of Pediococcus acidilactici BCC-1 as novel complex feed additives.