Perturbation of the gut microbiome in wild-caught freshwater turtles (Emydura macquarii macquarii) exposed to elevated PFAS levels

Per- and polyfluoroalkyl substances (PFAS) are environmentally persistent and pervasive. Understanding the toxicity of PFAS to wildlife is difficult, both due to the complexity of biotic and abiotic perturbations in the taxa under study and the practical and ethical problems associated with studying the impacts of environmental pollutants on free living wildlife. One avenue of inquiry into the effects of environmental pollutants, such as PFAS, is assessing the impact on the host gut microbiome. Here we show the microbial composition and biochemical functional outputs from the gut microbiome of sampled faeces from euthanised and necropsied wild-caught freshwater turtles (Emydura macquarii macquarii) exposed to elevated PFAS levels. The microbial community composition was profiled by 16S rRNA gene sequencing using a Nanopore MinION and the biochemical functional outputs of the gut microbiome were profiled using a combination of targeted central carbon metabolism metabolomics using liquid chromatography coupled to a triple quadrupole mass spectrometer (LC-QqQ-MS) and untargeted metabolomics using liquid chromatography coupled to a quadrupole time of flight mass spectrometer (LC-QToF-MS). Total PFAS was measured in the turtle serum using standard methods. These preliminary data demonstrated a 60-fold PFAS increase in impacted turtles compared to the sampled aquatic environment. The microbiome community was also impacted in the PFAS exposed turtles, with the ratio of Firmicutes-to-Bacteroidetes rising from 1.4 at the reference site to 5.5 at the PFAS impacted site. This ratio increase is indicative of host stress and dysfunction of the gut microbiome that was correlated with the biochemical metabolic function data, metabolites observed that are indications of stress and inflammation in the gut microbiome. Utilising the gut microbiome of sampled faeces collected from freshwater turtles provides a non-destructive avenue for investigating the impacts of PFAS in native wildlife, and provides an avenue to explore other contaminants in higher-order taxa within the environment.

Antidiabetic effect of an engineered bacterium Lactobacillus plantarum-pMG36e -GLP-1 in monkey model

Glucagon-like peptide-1 (GLP-1) reduces postprandial hyperglycaemia, but its short half-life inhibits clinical application. The aim of the current study was to evaluate the treatment efforts of an engineered strain, Lactobacillus plantarum-pMG36e-GLP-1 (L. plantarum-pMG36e-GLP-1), that continuously expresses GLP-1 in spontaneous type 2 diabetes mellitus (T2DM) monkeys. After 7 weeks of oral supplementation with L. plantarum-pMG36e-GLP-1, the fasting blood glucose (FPG) of monkeys was significantly (p < 0.05) reduced to a normal level and only a small amount of weight was lost. The results of metagenomic sequencing showed that L. plantarum-pMG36e-GLP-1 caused a substantial (p < 0.05) reduction in the intestinal pathogen Prevotella and marked enhancement of butyrate-producing Alistipes genera. According to the functional analysis using Kyoto Encyclopaedia of Genes and Genomes (KEGG) pathways, 19 metabolism-related pathways were significantly enriched in T2DM monkeys after treatment with L. plantarum-pMG36e-GLP-1. LC-MS faecal metabolomics analysis found 41 significant differential metabolites (11 higher and 30 lower) in monkeys after treatment pathways linked to the metabolism of cofactors and vitamins were the most relevant. The present study suggests that L. plantarum-pMG36e-GLP-1 had an impact on the gut microbial composition and faecal metabolomic profile in spontaneous T2DM monkeys and may be a novel candidate for diabetes treatment.

Linking the IL-17A immune response with NMR-based faecal metabolic profile in IBD patients treated with Mastiha

Dysregulation of intestinal immune response plays a critical role in the pathogenesis of Inflammatory Bowel Disease (IBD). Mastiha's anti-inflammatory properties are well established. Our aim was to investigate Mastiha's regulatory effect on IL-17A serum levels in IBD patients. Alterations of the faecal metabolome as a functional readout of microbial activity were explored. A randomized, double-blind, placebo-controlled, parallel-group design was applied for a total of 3 months in active and 6 months in inactive IBD patients. Serum IL-17A increased significantly in Mastiha group (p = 0.006), and the mean change differed significantly between Mastiha and placebo (p = 0.003) even after adjusting for age, sex and BMI (p = 0.001) in inactive patients. In inactive UC patients IL-17A decreased significantly only in placebo (p = 0.033). No significant differences were detected in active disease. Faecal metabolomics indicated that intervention with Mastiha influenced considerably the metabolic profile of IBD patients in remission exhibiting, in between others, increased levels of glycine and tryptophan. Glycine has been proposed to have a therapeutic effect against IBD, while tryptophan derivatives are involved in immunoregalutory mechanisms, such as the Th17 cells differentiation. Thus, it is quite possible that the immunoregulatory role of Mastiha in quiescent IBD involves the regulation of Th17 cells function and differentiation.