Search Results (3)

Background: This cross-sectional study aimed to identify the prevalence of Candida albicans and Malassezia globosa in children with severe early childhood caries and caries-free children in Hong Kong. Methods: This study first recruited a total of 80 children aged between 48 and 72 months old, 40 children with severe early childhood caries, and 40 caries-free children. The children were then further divided into four groups, with 20 children in each group: Group 1: Severe early childhood caries—C. albicans, Group 2: Severe early childhood caries—M. globosa, Group 3: Caries-free—C. albicans and Group 4: Caries-free—M. globosa. Saliva, plaque, and caries lesion samples were collected from participants with severe early childhood caries, while only saliva and plaque samples were collected from caries-free participants. Caries status of the primary molars was assessed using WHO’s decayed, missing, and filled tooth index, and the severity of cavitated lesions was determined based on International Caries Diagnosis and Assessment System criteria as caries code 5 or 6. The samples were analyzed using an Internal Transcribed Space and Quantitative Real-Time Polymerase Chain Reaction. Results:C. albicans was more prevalent in saliva and plaque samples of severe early childhood caries than in the caries-free group. Proportion of C. albicans in both saliva and plaque samples differed significantly between severe early childhood caries and caries-free groups (p < 0.05). Within the severe early childhood caries group, the proportion of children with C. albicans varied between 6 and 46%. No significant difference in M. globosa load was found between plaque samples of the severe early childhood caries and caries-free groups (p = 0.159). Conversely, no significant difference in M. globosa load was observed between saliva samples of severe early childhood caries and caries-free groups (p = 0.051). Conclusions: This study demonstrated a strong association between C. albicans and severe early childhood caries. M. globosa was detected in both the caries-free and severe early childhood caries groups, albeit at low levels. Full article

Diacylglycerols (DAGs) display huge application prospectives in food industries. Therefore, new strategies to produce diacylglycerides are needed. Malassezia globose lipase (SMG1) could be used to synthesize DAGs. However, the poor thermostability of SMG1 seriously hampers its application. Herein, a rational design was used to generate a more thermostable SMG1. Compared with the wild type (WT), the M5D mutant (Q34P/A37P/M176V/G177A/M294R/ G28C-P206C), which contains five single-point mutations and one additional disulfide bond, displayed a 14.0 °C increase in the melting temperature (T_m), 5 °C in the optimal temperature, and 1154.3-fold in the half-life (t_1/2) at 55 °C. Meanwhile, the specific activity towards DAGs of the M5D variant was improved by 3.0-fold compared to the WT. Molecular dynamics (MD) simulations revealed that the M5D mutant showed an improved rigid structure. Additionally, the WT and the M5D variants were immobilized and used for the production of DAGs. Compared with the WT, the immobilized M5D-catalyzed esterification showed a 9.1% higher DAG content and a 22.9% increase in residual activity after nine consecutive cycles. This study will pave the way for the industrial application of SMG1. Full article

Recent advances in next-generation sequencing and metagenomic studies have provided insights into the microbial profile of different body sites. However, research on the microbial composition of urine is limited, particularly in children. The goal of this study was to optimize and develop reproducible metagenome and virome protocols using a small volume of urine samples collected from healthy children. We collected midstream urine specimens from 40 healthy children. Using the metagenomics shotgun approach, we tested various protocols. Different microbial roots such as Archaea, Bacteria, Eukaryota, and Viruses were successfully identified using our optimized urine protocol. Our data reflected much variation in the microbial fingerprints of children. Girls had significantly higher levels of Firmicutes, whereas boys had significantly higher levels of Actinobacteria. The genus Anaerococcus dominated the urinary bacteriome of healthy girls, with a significant increase in Anaerococcus prevotii, Anaerococcus vaginalis, and Veillonella parvula (p-value < 0.001) when compared with that of boys. An increased relative abundance of Xylanimonas and Arthrobacter, with a significantly high abundance of Arthrobacter sp. FB24 (p-value 0.0028) and Arthrobacter aurescences (p-value 0.015), was observed in boys. The urinary mycobiome showed a significant rise in the genus Malassezia and Malassezia globose fungus (p-value 0.009) in girls, whereas genus Saccharomyces (p-value 0.009) was significantly high in boys. The beta diversity of the urinary mycobiome was found to differ between different age groups. Boys had significantly more Mastadenovirus and Human mastadenovirus-A in their urinary virome than girls. With increasing age, we noticed an increase in the relative abundance of the order Caudovirales. Our optimized protocols allowed us to identify the unique microbes for each sex by using an adequate volume of urine (3–10 mL) to screen for the bacteriome, mycobiome, and virome profiles in the urine of healthy children. To the best of our knowledge, this is the first study to characterize the metagenomics profiles of urine in a healthy pediatric population. Full article