RESUMEN
Age-related gut bacterial changes during infancy have been widely studied, but it remains still unknown how these changes are associated with immune cell composition. This study's aim was to explore if the temporal development of gut bacteria during infancy prospectively affects immune cell composition. Faecal bacteria and short-chain fatty acids were analysed from 67 PreventADALL study participants at four timepoints (birth to 12 months) using reduced metagenome sequencing and gas chromatography. Immune cell frequencies were assessed using mass cytometry in whole blood samples at 12 months. The infants clustered into four groups based on immune cell composition: clusters 1 and 2 showed a high relative abundance of naïve cells, cluster 3 exhibited increased abundance of classical- and non-classical monocytes and clusters 3 and 4 had elevated neutrophil levels. At all age groups, we did observe significant associations between the gut microbiota and immune cell clusters; however, these were generally from low abundant species. Only at 6 months of age we observed significant associations between abundant (>8%) species and immune cell clusters. Bifidobacterium adolescentis and Porphyromonadaceae are associated with cluster 1, while Bacteroides fragilis and Bifidobacterium longum are associated with clusters 3 and 4 respectively. These species have been linked to T-cell polarization and maturation. No significant correlations were found between short-chain fatty acids and immune cell composition. Our findings suggest that abundant gut bacteria at 6 months may influence immune cell frequencies at 12 months, highlighting the potential role of gut microbiota in shaping later immune cell composition.
Asunto(s)
Heces , Microbioma Gastrointestinal , Humanos , Lactante , Microbioma Gastrointestinal/inmunología , Masculino , Femenino , Heces/microbiología , Recién Nacido , Bacterias/inmunología , Bacterias/clasificación , Ácidos Grasos Volátiles/metabolismo , Metagenoma , Estudios ProspectivosRESUMEN
Bacterial spores are problematic in agriculture, the food industry, and healthcare, with the fallout costs from spore-related contamination being very high. Spores are difficult to detect since they are resistant to many of the bacterial disruption techniques used to bring out the biomarkers necessary for detection. Because of this, effective and practical spore disruption methods are desirable. In this study, we demonstrate the efficiency of a compact microfluidic lab-on-chip built around a coplanar waveguide (CPW) operating at 2.45 GHz. We show that the CPW generates an electric field hotspot of â¼10 kV/m, comparable to that of a commercial microwave oven, while using only 1.2 W of input power and thus resulting in negligible sample heating. Spores passing through the microfluidic channel are disrupted by the electric field and release calcium dipicolinic acid (CaDPA), a biomarker molecule present alongside DNA in the spore core. We show that it is possible to detect this disruption in a bulk spore suspension using fluorescence spectroscopy. We then use laser tweezers Raman spectroscopy (LTRS) to show the loss of CaDPA on an individual spore level and that the loss increases with irradiation power. Only 22% of the spores contain CaDPA after exposure to 1.2 W input power, compared to 71% of the untreated control spores. Additionally, spores exposed to microwaves appear visibly disrupted when imaged using scanning electron microscopy (SEM). Overall, this study shows the advantages of using a CPW for disrupting spores for biomarker release and detection.