Verrucomicrobiotal methanotrophs are thermoacidophilic methane oxidizers that have been isolated from volcanic and geothermal regions of the world. We used a metagenomic approach that entailed obtaining the whole genome sequence of a verrucomicrobiotal methanotroph from a microbial consortium enriched from samples obtained from Nymph Lake (89.9 °C, pH 2.73) in Yellowstone National Park in the USA. To identify and reconstruct the verrucomicrobiotal genome from Illumina NovaSeq 6000 sequencing data, we constructed a bioinformatic pipeline with various combinations of de novo assembly, alignment, and binning algorithms. Based on the marker gene (pmoA), we identified and assembled the Candidatus Methylacidiphilum sp. YNP IV genome (2.47 Mbp, 2392 ORF, and 41.26% GC content). In a comparison of average nucleotide identity between Ca. Methylacidiphilum sp. YNP IV and Ca. Methylacidiphilum fumariolicum SolV, its closest 16S rRNA gene sequence relative, is lower than 95%, suggesting that Ca. Methylacidiphilum sp. YNP IV can be regarded as a different species. The Ca. Methylacidiphilum sp. YNP IV genome assembly showed most of the key genes for methane metabolism, the CBB pathway for CO₂ fixation, nitrogen fixation and assimilation, hydrogenases, and rare earth elements transporter, as well as defense mechanisms. The assembly and reconstruction of a thermoacidophilic methanotroph belonging to the Verrucomicrobiota phylum from a geothermal environment adds further evidence and knowledge concerning the diversity of biological methane oxidation and on the adaptation of this geochemically relevant reaction in extreme environments.

Peach (Prunus persica) is one of the representative climacteric fruits susceptible to environmental stresses, including microbial contamination. This article analyzed major findings from the literature on pre- and post-harvest technologies for maintaining the quality of peach fruit to figure out the strengths and limitations of each treatment strategy. The key implication from studies of pre-harvest agents directly applied to the fruit surface or supplemented as fertilizer was the application of a mixture regarding substances with diverse working mechanisms to prevent excessive use of the agent. The common objectives of previous research on pre-harvest treatments were not only the improvement in the quality of harvested fruit but also the storability during long-term refrigeration due to the short lifespan of peaches. In the case of post-harvest treatments, the efficacy was considerably affected by various determinant factors (e.g., a cultivar of fruit, the sort of technologies, and storage environments), and thus operating conditions optimized for peach fruit were described in this article. Whereas, although the combined treatment of technologies categorized into principles (physical, chemical, and biological approaches) has been adopted to achieve the synergistic effect, undesirable antagonistic effects (i.e., the inhibition of efficacies expectable from singular treatments) were also reported to highlight the importance for exploring adequate treatment conditions.

Bacterial co-culture studies using synthetic gut microbiomes have reported novel research designs to understand the underlying role of bacterial interaction in the metabolism of dietary resources and community assembly of complex microflora. Since lab-on-a-chip mimicking the gut (hereafter “gut-on-a-chip”) is one of the most advanced platforms for the simulative research regarding the correlation between host health and microbiota, the co-culture of the synthetic bacterial community in gut-on-a-chip is expected to reveal the diet–microbiota relationship. This critical review analyzed recent research on bacterial co-culture with perspectives on the ecological niche of commensals, probiotics, and pathogens to categorize the experimental approaches for diet-mediated management of gut health as the compositional and/or metabolic modulation of the microbiota and the control of pathogens. Meanwhile, the aim of previous research on bacterial culture in gut-on-a-chip has been mainly limited to the maintenance of the viability of host cells. Thus, the integration of study designs established for the co-culture of synthetic gut consortia with various nutritional resources into gut-on-a-chip is expected to reveal bacterial interspecies interactions related to specific dietary patterns. This critical review suggests novel research topics for co-culturing bacterial communities in gut-on-a-chip to realize an ideal experimental platform mimicking a complex intestinal environment.