Adolescent alcohol use is associated with differences in the diversity and composition of the oral microbiome

BACKGROUND

Adolescence is a sensitive stage of oral microbial development that often coincides with the initiation and escalation of alcohol use. Thus, adolescents may be particularly susceptible to alcohol-induced alterations in the oral microbiome, though minimal research has been done in this area. Understanding the connection between the oral microbiome and alcohol use during adolescence is important to understand fully the biological consequences of alcohol use to mitigate potential adverse outcomes.

METHODS

Saliva samples were collected from adolescents aged 17-19 who used alcohol heavily (n = 21, 52.4% female) and those who did not use alcohol or any other substances (n = 18, 44.4% female). We utilized 16S rRNA sequencing to examine differences in microbial diversity and composition between the groups.

RESULTS

For alpha diversity, evenness was significantly lower in the drinking group than the control group as indicated by Pielou's evenness, Shannon, and Simpson indices. There were no statistically significant findings for beta diversity. Differential abundance analyses revealed higher abundances of Rothia and Corynebacterium in the alcohol-using group using both centered-log-ratio and relative abundance normalization. These genera are known for their high capacity to convert alcohol into acetaldehyde, a toxic metabolite reported to play a role in the neurobiological effects of alcohol. An unclassified Clostridia UCG-014, Streptobacillus, Comamonas, unclassified Lachnospiraceae, and Parvimonas were also identified as significantly different between groups when using only one of the normalization techniques.

CONCLUSIONS

This is the first study designed specifically to compare the oral microbiome of adolescents who use alcohol with that of control participants. Our findings reveal distinct alcohol-related differences in microbial composition and taxon abundance, emphasizing the importance of understanding the impact on the oral microbiome of alcohol use during adolescence. Because the oral microbiome is malleable, this study provides foundational work for future prevention and intervention studies.

Acinetobacter calcoaceticus is Well Adapted to Withstand Intestinal Stressors and Modulate the Gut Epithelium

Background: The gastrointestinal tract has been speculated to serve as a reservoir for Acinetobacter, however little is known about the ecological fitness of Acinetobacter strains in the gut. Likewise, not much is known about the ability of Acinetobacter to consume dietary, or host derived nutrients or their capacity to modulate host gene expression. Given the increasing prevalence of Acinetobacter in the clinical setting, we sought to characterize how A. calcoaceticus responds to gut-related stressors and identify potential microbe-host interactions. Materials and Methods: To accomplish these aims, we grew clinical isolates and commercially available strains of A. calcoaceticus in minimal media with different levels of pH, osmolarity, ethanol and hydrogen peroxide. Utilization of nutrients was examined using Biolog phenotypic microarrays. To examine the interactions of A. calcoaceticus with the host, inverted murine organoids where the apical membrane is exposed to bacteria, were incubated with live A. calcoaceticus, and gene expression was examined by qPCR. Results: All strains grew modestly at pH 6, 5 and 4; indicating that these strains could tolerate passage through the gastrointestinal tract. All strains had robust growth in 0.1 and 0.5 M NaCl concentrations which mirror the small intestine, but differences were observed between strains in response to 1 M NaCl. Additionally, all strains tolerated up to 5% ethanol and 0.1% hydrogen peroxide. Biolog phenotypic microarrays revealed that A. calcoaceticus strains could use a range of nutrient sources, including monosaccharides, disaccharides, polymers, glycosides, acids, and amino acids. Interestingly, the commercially available A. calcoaceticus strains and one clinical isolate stimulated the pro-inflammatory cytokines Tnf, Kc, and Mcp-1 while all strains suppressed Muc13 and Muc2. Conclusion: Collectively, these data demonstrate that A. calcoaceticus is well adapted to dealing with environmental stressors of the gastrointestinal system. This data also points to the potential for Acinetobacter to influence the gut epithelium.

Characterizing the mucin-degrading capacity of the human gut microbiota

Mucin-degrading microbes are known to harbor glycosyl hydrolases (GHs) which cleave specific glycan linkages. Although several microbial species have been identified as mucin degraders, there are likely many other members of the healthy gut community with the capacity to degrade mucins. The aim of the present study was to systematically examine the CAZyme mucin-degrading profiles of the human gut microbiota. Within the Verrucomicrobia phylum, all Akkermansia glycaniphila and muciniphila genomes harbored multiple gene copies of mucin-degrading GHs. The only representative of the Lentisphaerae phylum, Victivallales, harbored a GH profile that closely mirrored Akkermansia. In the Actinobacteria phylum, we found several Actinomadura, Actinomyces, Bifidobacterium, Streptacidiphilus and Streptomyces species with mucin-degrading GHs. Within the Bacteroidetes phylum, Alistipes, Alloprevotella, Bacteroides, Fermenitomonas Parabacteroides, Prevotella and Phocaeicola species had mucin degrading GHs. Firmicutes contained Abiotrophia, Blautia, Enterococcus, Paenibacillus, Ruminococcus, Streptococcus, and Viridibacillus species with mucin-degrading GHs. Interestingly, far fewer mucin-degrading GHs were observed in the Proteobacteria phylum and were found in Klebsiella, Mixta, Serratia and Enterobacter species. We confirmed the mucin-degrading capability of 23 representative gut microbes using a chemically defined media lacking glucose supplemented with porcine intestinal mucus. These data greatly expand our knowledge of microbial-mediated mucin degradation within the human gut microbiota.

A study of some factors that influence the iodination of ox insulin

1. The influence of carrier iodide, iodine monochloride and pH on the labelling of ox insulin with (131)I by the iodine monochloride method have been studied. 2. The quantitative effect of the iodide in the radioactive iodine preparation was that predicted from a calculation of its specific activity. No other interfering factors were detected in the [(131)I]iodide solutions used. 3. Increasing the molar ratio of iodine monochloride to insulin resulted in an increase followed progressively by a decrease in the proportion of (131)I bound, while the total iodine bound increased to an amount characteristic of pH and thereafter remained constant. 4. The influence of pH on the iodination of insulin with iodine monochloride was complex and the pH curve showed two maxima, at pH2.8 and 6.4. At pH2.8 it was not possible to exceed 8 atoms of iodine bound per molecule by increasing the molar ratio of iodine monochloride. Similarly, at pH6.4 the substitution value of 11.5 atoms of iodine per molecule could not be exceeded. 5. Iodinated insulins containing an average of 1.96, 2.74, 6.0 and 7.0 atoms of iodine per molecule fully retained the ability to bind guinea-pig anti-(ox insulin) serum, and the ability to compete with unlabelled insulin for antibody sites only became significantly changed in the most highly substituted preparations and in the presence of large concentrations of unlabelled insulin. 6. The method for the iodination of insulin with 98% incorporation of (131)I by using chloramine-t is described. 7. (131)I-iodinated insulin prepared with graded quantities of chloramine-t in excess of that required for efficient labelling was less efficiently bound by guinea-pig anti-(ox insulin) serum than insulin labelled by the iodine monochloride method.

Ulcerate Enteritis in Pigeons

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