Periodontal treatment causes a longitudinal increase in nitrite-producing bacteria

BackgroundThe oral microbiome-dependent nitrate (NO3−)–nitrite (NO2−)–nitric oxide (NO) pathway may help regulate blood pressure. NO2−-producing bacteria in subgingival plaque are reduced in relative abundance in patients with untreated periodontitis compared with periodontally healthy patients. In periodontitis patients, the NO2−-producing bacteria increase several months after periodontal treatment. The early effects of periodontal treatment on NO2−-producing bacteria and the NO3−–NO2−-NO pathway remain unknown. The aim of this study was to determine how periodontal treatment affects the oral NO2−-producing microbiome and salivary NO3− and NO2− levels over time.MethodsThe subgingival microbiota of 38 periodontitis patients was analysed before (baseline [BL]) and 1, 7 and 90 days after periodontal treatment. Changes in NO2−producing bacteria and periodontitis-associated bacteria were determined by 16s rRNA Illumina sequencing. Saliva samples were collected at all-time points to determine NO3− and NO2− levels using gas-phase chemiluminescence.ResultsA significant increase was observed in the relative abundance of NO2−-producing species between BL and all subsequent timepoints (all p &lt; 0.001). Periodontitis-associated species decreased at all timepoints, relative to BL (all p &lt; 0.02). NO2−-producing species negatively correlated with periodontitis-associated species at all timepoints, with this relationship strongest 90 days post-treatment (ρ = −0.792, p &lt; 0.001). Despite these findings, no significant changes were found in salivary NO3− and NO2− over time (all p &gt; 0.05).ConclusionsPeriodontal treatment induced an immediate increase in the relative abundance of health-associated NO2−-producing bacteria. This increase persisted throughout periodontal healing. Future studies should test the effect of periodontal treatment combined with NO3− intake on periodontal and cardiovascular health.</p

Phylogenetic and functional characterization of the distal intestinal microbiome of rainbow trout Oncorhynchus mykiss from both farm and aquarium settings

Aims&nbsp; This study focused on comparing the phylogenetic composition and functional potential of the intestinal microbiome of rainbow trout sourced from both farm and aquarium settings.&nbsp; Methods and Results&nbsp; Samples of distal intestinal contents were collected from fish and subjected to high throughput 16S rRNA sequencing, to accurately determine the composition of the intestinal microbiome. The predominant phyla identified from both groups were Tenericutes, Firmicutes, Proteobacteria, Spirochaetae and Bacteroidetes. A novel metagenomic tool, PICRUSt, was used to determine the functional potential of the bacterial communities present in the rainbow trout intestine. Pathways concerning membrane transport activity were dominant in the intestinal microbiome of all fish samples. Furthermore, this analysis revealed that gene pathways relating to metabolism, and in particular amino acid and carbohydrate metabolism, were upregulated in the rainbow trout intestinal microbiome.&nbsp; Conclusions&nbsp; The results suggest that the structure of the intestinal microbiome in farmed rainbow trout may be similar regardless of where the fish are located and hence could be shaped by host factors. Differences were, however, noted in the microbial community membership within the intestine of both fish populations, suggesting that more sporadic taxa could be unique to each environment and may have the ability to colonize the rainbow trout gastrointestinal tract. Finally, the functional analysis provides evidence that the microbiome of rainbow trout contains genes that could contribute to the metabolism of dietary ingredients and therefore may actively influence the digestive process in these fish.&nbsp; Significance and Impact of the Study&nbsp; To better understand and exploit the intestinal microbiome and its impact on fish health, it is vital to determine its structure, diversity and potential functional capacity. This study improves our knowledge of these areas and suggests that the intestinal microbiome of rainbow trout may play an important role in the digestive physiology of these fish

Molecular Taxonomic Profiling of Bacterial Communities in a Gilthead Seabream (Sparus aurata) Hatchery

As wild fish stocks decline worldwide, land-based fish rearing is likely to be of increasing relevance to feeding future human generations. Little is known about the structure and role of microbial communities in fish aquaculture, particularly at larval developmental stages where the fish microbiome develops and host animals are most susceptible to disease. We employed next-generation sequencing (NGS) of 16S rRNA gene reads amplified from total community DNA to reveal the structure of bacterial communities in a gilthead seabream (Sparus aurata) larviculture system. Early-(2 days after hatching) and late-stage (34 days after hatching) fish larvae presented remarkably divergent bacterial consortia, with the genera Pseudoalteromonas, Marinomonas, Acinetobacter, and Acidocella (besides several unclassified Alphaproteobacteria) dominating the former, and Actinobacillus, Streptococcus, Massilia, Paracoccus, and Pseudomonas being prevalent in the latter. A significant reduction in rearing-water bacterial diversity was observed during the larviculture trial, characterized by higher abundance of the Cryomorphaceae family (Bacteroidetes), known to populate microniches with high organic load, in late-stage rearing water in comparison with early-stage rearing-water. Furthermore, we observed the recruitment, into host tissues, of several bacterial phylotypes-including putative pathogens as well as mutualists-that were detected at negligible densities in rearing-water or in the live feed (i.e., rotifers and artemia). These results suggest that, besides host-driven selective forces, both the live feed and the surrounding rearing environment contribute to shaping the microbiome of farmed gilthead sea-bream larvae, and that a differential establishment of host-associated bacteria takes place during larval development.for ScienPortuguese Foundation ce and Technology [PTDC/MAR/112792/2009, UID/Multi/04326/2013, UID/BIO/04565/2013]; Programa Operacional Regional de Lisboa [007317]info:eu-repo/semantics/publishedVersio