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The Role of the Microbiome in Mood
Published in David Perlmutter, The Microbiome and the Brain, 2019
Kirsten Tillisch, Arpana Gupta
Evaluating gut microbial composition and metabolic function in depressed versus non-depressed individuals has been one popular method for investigating the relevance of the BGMA to depression. Several studies have looked for evidence of altered microbial diversity in depressed individuals, but most have shown no difference compared to controls; surprisingly, one study even showed increased diversity, a finding most often considered as a sign of health (Naseribafrouei, Hestad et al. 2014; Jiang, Ling et al. 2015; Zheng, Zeng et al. 2016; Chen, Zheng et al. 2018). Evaluation of the specific taxa of bacteria in depression has also been inconsistent. As Bifidobacteria and Lactobacillus are often considered the “good bacteria” and are most often included in probiotic interventions, many studies have evaluated their abundance in depression. One study showed lower abundance of Lactobacillus in depression. (Aizawa, Tsuji et al. 2016), and two studies showed increased levels of bacteria from the genus Alistipes in depression with one of them also showing correlation of depressive symptoms with this finding. Alistipes has previously been shown in preclinical studies to increase with stress and to be associated with inflammation, while in humans it has been associated with irritable bowel syndrome (IBS) (Naseribafrouei, Hestad et al. 2014).
Classification of Parabacteroides distasonis and other Bacteroidetes using O- antigen virulence gene: RfbA-Typing and hypothesis for pathogenic vs. probiotic strain differentiation
Published in Gut Microbes, 2022
Nicholas C. Bank, Vaidhvi Singh, Alex Rodriguez-Palacios
Parabacteroides distasonis rfbA gene sequences previously collected from NCBI were compiled in CLC Viewer 8.0 (commercially available) and used to construct two alignments and phylogenetic trees: one alignment and tree for the Pdis rfbA nucleotide sequences and the second for the translated amino acid sequences. Additionally, a third alignment and tree including rfbA gene sequences from Pdis, other Parabacteroides spp., Bacteroides spp., Alistipes spp., Prevotella spp., Escherichia spp., Klebsiella spp., Salmonella spp., and Shigella spp., were constructed to provide evolutionary context and for observation of clustering patterns. Results were used to determine phylogenetic relatedness and rfbA gene variance within Pdis strains as well as between Pdis and other bacterial species. A separate phylogenetic analysis of lpxK gene nucleotide and amino acid sequences was performed, the results of which were used to determine the comparative discriminatory ability of the rfbA gene to aid in strain characterization.
The intestinal microbiota and metabolites in patients with anorexia nervosa
Published in Gut Microbes, 2021
Petra Prochazkova, Radka Roubalova, Jiri Dvorak, Jakub Kreisinger, Martin Hill, Helena Tlaskalova-Hogenova, Petra Tomasova, Helena Pelantova, Martina Cermakova, Marek Kuzma, Josef Bulant, Martin Bilej, Kvido Smitka, Alena Lambertova, Petra Holanova, Hana Papezova
Patient renourishment led to minor bacterial composition changes (Table 6), which are supported by the positive correlation of hospitalization length and bacteriome divergence of AN1 vs. AN2. The bacteriome of patients after weight gain was still more similar to the bacteriome of patients at admission than to the bacterial composition of healthy controls, which is in accordance with Mack et al.13 We detected a significant change in a subset of OTUs that did not correspond to the results from a separate genus-level analysis; however, these OTUs may play an important role in AN pathophysiology. For example, only a single Alistipes OTU (out of 14 detected) exhibited a significant abundance increase in AN1. This OTU_3215 is related to A. finegoldi and A. onderdonkii (Fig. S3). Different strains of the Alistipes genus were shown to have unique physiological roles associated with different diseases and disorders.25 Since Alistipes can hydrolyze tryptophan (serotonin precursor) to indole and thus decreases serotonin availability, Alistipes increased abundance can disrupt the gut-brain axis. Further, a decrease in serotonin is associated with depression.26
Naturalizing laboratory mice by housing in a farmyard-type habitat confers protection against colorectal carcinogenesis
Published in Gut Microbes, 2021
Henriette Arnesen, Thomas C. A. Hitch, Christina Steppeler, Mette Helen Bjørge Müller, Linn Emilie Knutsen, Gjermund Gunnes, Inga Leena Angell, Ida Ormaasen, Knut Rudi, Jan Erik Paulsen, Thomas Clavel, Harald Carlsen, Preben Boysen
Gut microbes associated with CRC vary greatly between studies and experimental setups. Although a lower relative abundance of Firmicutes was observed in our feralized B6 mice, OTUs with closest sequence similarities to Lactobacillus and Limosilactobacillus species were enriched. Lactobacillus has been reported to be predictive of a light tumor burden in the AOM/DSS model and various Lactobacillus strains have been shown to reduce gastrointestinal inflammation.48 However, Bifidobacterium strains have also been shown to confer anticancer effects,53 and we found higher relative abundance of this genus in lab B6 mice. Moreover, Lachnospiraceae, Clostridiales, Proteobacteria, Alistipes and Aneroplasma are all examples of taxa for which high baseline relative abundance has been associated with increased tumor burden in AOM/DSS model.48 In our AOM/DSS experiment, several OTUs with highest similarity to Lachnospiraceae spp., such as Lacrimispora spp., Ruminococcus gnavus, Cuneatibacter caecimuris, and Stomatobaculum longum, were enriched in lab B6 mice. Yet, Alistipes spp. and Proteobacteria were enriched in feralized B6 mice. These findings were not consistent with observations from the A/J Min/+ trial, emphasizing that different community structures could confer beneficial effects in different models of carcinogenesis.