Soil pH, developmental stages and geographical origin differently influence the root metabolomic diversity and root-related microbial diversity of Echium vulgare from native habitats.

Improved understanding of the complex interaction between plant metabolism, environmental conditions and the plant-associated microbiome requires an interdisciplinary approach: Our hypothesis in our multiomics study posited that several environmental and biotic factors have modulating effects on the microbiome and metabolome of the roots of wild Echium vulgare plants. Furthermore, we postulated reciprocal interactions between the root metabolome and microbiome. We investigated the metabolic content, the genetic variability, and the prokaryotic microbiome in the root systems of wild E. vulgare plants at rosette and flowering stages across six distinct locations. We incorporated the assessment of soil microbiomes and the measurement of selected soil chemical composition factors. Two distinct genetic clusters were determined based on microsatellite analysis without a consistent alignment with the geographical proximity between the locations. The microbial diversity of both the roots of E. vulgare and the surrounding bulk soil exhibited significant divergence across locations, varying soil pH characteristics, and within the identified plant genetic clusters. Notably, acidophilic bacteria were characteristic inhabitants of both soil and roots under acidic soil conditions, emphasizing the close interconnectedness between these compartments. The metabolome of E. vulgare significantly differed between root samples from different developmental stages, geographical locations, and soil pH levels. The developmental stage was the dominant driver of metabolome changes, with significantly higher concentrations of sugars, pyrrolizidine alkaloids, and some of their precursors in rosette stage plant roots. Our study featured the complex dynamics between soil pH, plant development, geographical locations, plant genetics, plant metabolome and microbiome, shedding light on existing knowledge gaps.

Metabolite Production in Alkanna tinctoria Links Plant Development with the Recruitment of Individual Members of Microbiome Thriving at the Root-Soil Interface.

Plants are naturally associated with diverse microbial communities, which play significant roles in plant performance, such as growth promotion or fending off pathogens. The roots of Alkanna tinctoria L. are rich in naphthoquinones, particularly the medicinally used enantiomers alkannin and shikonin and their derivatives. Former studies already have shown that microorganisms may modulate plant metabolism. To further investigate the potential interaction between A. tinctoria and associated microorganisms, we performed a greenhouse experiment in which A. tinctoria plants were grown in the presence of three distinct soil microbiomes. At four defined plant developmental stages, we made an in-depth assessment of bacterial and fungal root-associated microbiomes as well as all extracted primary and secondary metabolite content of root material. Our results showed that the plant developmental stage was the most important driver influencing the plant metabolite content, revealing peak contents of alkannin/shikonin derivatives at the fruiting stage. Plant root microbial diversity was influenced both by bulk soil origin and to a small extent by the developmental stage. The performed correlation analyses and cooccurrence networks on the measured metabolite content and the abundance of individual bacterial and fungal taxa suggested a dynamic and at times positive or negative relationship between root-associated microorganisms and root metabolism. In particular, the bacterial genera Labrys and Allorhizobium-Neorhizobium-Pararhizobium-Rhizobium as well as four species of the fungal genus Penicillium were found to be positively correlated with higher content of alkannins. IMPORTANCE Previous studies have shown that individual, isolated microorganisms may influence secondary metabolism of plants and induce or stimulate the production of medicinally relevant secondary metabolism. Here, we analyzed the microbiome-metabolome linkage of the medicinal plant Alkanna tinctoria, which is known to produce valuable compounds, particularly the naphthoquinones alkannin and shikonin and their derivatives. A detailed bacterial and fungal microbiome and metabolome analysis of A. tinctoria roots revealed that the plant developmental stage influenced root metabolite production, whereas soil inoculants from three different geographical origins in which plants were grown shaped root-associated microbiota. Metabolomes of plant roots of the same developmental stage across different soils were highly similar, pinpointing to plant maturity as the primary driver of secondary metabolite production. Correlation and network analyses identified bacterial and fungal taxa showing a positive relationship between root-associated microorganisms and root metabolism. In particular, the bacterial genera Allorhizobium-Neorhizobium-Pararhizobium-Rhizobium and Labrys as well as the fungal species of genus Penicillium were found to be positively correlated with higher content of alkannins.

Potential consumer exposures to low/no calorie sweeteners: a refined assessment based upon market intelligence on use frequency, and consideration of niche applications.

Data on current use levels of E950 acesulfame K, E952 cyclamic acid and its Na and Ca salts, E954 saccharin and its Na, K and Ca salts, E955 sucralose and E957 thaumatin, have been collected by the European food and drink industry in response to an EFSA call for data in support of its upcoming review of low/no calorie sweeteners (LNCSs). Careful evaluation of these data is necessary to allow for reasonably realistic estimations of consumer intake. Consumer patterns of product use and in particular of "niche" products, which are not likely to represent general LNCS exposure, are important to consider. Market survey data can identify food categories where the frequency of use of a given LNCS is so low as to represent a niche use of the product. The subsequent incorporation of information about these niche products can provide a relevant improvement in obtaining realistic exposure calculations. Using this approach, estimates of exposure are found to be comparable with previously published papers on intake and show levels generally below current ADIs, for most population groups.

Obstructive Sleep Apnea and Chronic Kidney Disease.

Chronic kidney disease (CKD) often accompanies obstructive sleep apnea (OSA). A causative connection of the two disease entities is uncertain. However, eliminating OSA improves the prognosis of CKD patients. In the present study we examined a possible relationship between OSA and CKD, and whether there would be a mutual enhancing interaction in the severity of the two diseases. The study was of a retrospective nature and encompassed 382 patients over the period of 1 January 2014-30 June 2015. The OSA diagnosis was supported by a polysomnographic examination in 363 (95.0%) patients. Blood samples were taken for the determination of kidney function indices. The influence on OSA and CKD of comorbidities also was examined. We found a high probability of a simultaneous occurrence of OSA and CKD; with the odds ratio of 3.94 (95% CI 1.5-10.3%; p = 0.005). The 363 patients with OSA were stratified into 73 (20.1%) mild, 98 (27.0%) moderate, and 192 (52.9%) severe OSA cases according to the apnea-hypopnea index. CKD was found in 43 (58.9%) patients with mild OSA, 73 (74.5%) with moderate OSA, and 137 (71.4%) with severe OSA. Most OSA patients also suffered from hypertension and obesity. For comparison, CKD was detected in 7 (36.8%) out of the 19 patients without OSA (p < 0.003). We conclude that CKD develops significantly more often in patients with OSA than in those without it, and CKD frequency increases with the severity of OSA.

Cross-feeding between Bifidobacterium longum BB536 and acetate-converting, butyrate-producing colon bacteria during growth on oligofructose.

In vitro coculture fermentations of Bifidobacterium longum BB536 and two acetate-converting, butyrate-producing colon bacteria, Anaerostipes caccae DSM 14662 and Roseburia intestinalis DSM 14610, with oligofructose as the sole energy source, were performed to study interspecies interactions. Two clearly distinct types of cross-feeding were identified. A. caccae DSM 14662 was not able to degrade oligofructose but could grow on the fructose released by B. longum BB536 during oligofructose breakdown. R. intestinalis DSM 14610 could degrade oligofructose, but only after acetate was added to the medium. Detailed kinetic analyses of oligofructose breakdown by the last strain revealed simultaneous degradation of the different chain length fractions, in contrast with the preferential degradation of shorter fractions by B. longum BB536. In a coculture of both strains, initial oligofructose degradation and acetate production by B. longum BB536 took place, which in turn also allowed oligofructose breakdown by R. intestinalis DSM 14610. These and similar cross-feeding mechanisms could play a role in the colon ecosystem and contribute to the combined bifidogenic/butyrogenic effect observed after addition of inulin-type fructans to the diet.