MicrobiologyOpen

The presence of vitamin B₁₂ has a significant effect on carbon isotope effects, consistent with an isotope masking effect. We interpret this in the context of predicted enzyme structures.

A method for extracting high-molecular-weight DNA from Streptococcus spp., suitable for resource-limited settings, was optimized. The extracted DNA was used for nanopore whole-genome sequencing. This sequencing technique is valuable for the rapid diagnosis of diseases in warm water aquaculture, such as streptococcosis, under field conditions in low- and middle-income countries. It provides near real-time information on species, serotype, and the presence of plasmids. This was demonstrated by the discovery of a 15 kb low copy number mobilizable plasmid in Streptococcus iniae, the first reported in this species, which we named pSI1.

We used rbcL and 16S rRNA gene sequencing to characterize phytoplankton and bacterial communities in size-fractionated samples. Our correlation analysis between the most abundant phytoplankton and bacterial operational taxonomic units revealed distinct bacterial groups associated with the dimethylsulfoniopropionate (DMSP) producer Phaeocystis, including SAR11, SAR116, Magnetospira, and Planktomarina, or the diatom Thalassiosira, including Polaribacter, Sulfitobacteria, Erythrobacter, and Sphingobium. These results suggest unique associations between phytoplankton and bacterial taxa, which could play significant roles in nutrient cycling in the Southern Ocean.

This research examined the stability and resilience of a consortium of human gut bacteria, namely Akkermansia muciniphila, Bacteroides thetaiotaomicron, and Faecalibacterium prausnitzii, in a nutrient-rich medium using mucin as the carbon source. The study employed an isothermal microcalorimeter to monitor the growth of individual strains and their consortium. The results indicated a slight metabolic interaction between the strains, a stability and acute resilience of the consortium composition.

This study reveals that several enzymes involved in the central metabolism of Bacteroides fragilis are regulated by protein-protein interactions with pirin proteins. We observed changes in susceptibility to the antimicrobials metronidazole and amixicile in various metabolic mutants. Amixicile, a novel inhibitor that binds to thiamine⁻diphosphate dependent enzymes, has proven effective in eliminating B. fragilis in a model of intra-abdominal infection. Furthermore, we identified a 2-ketoacid: ferredoxin oxidoreductase as essential for growth and proposed its multifunctional roles.

Contrary to previous studies, the natural resistance of Rickettsia, a genus of intracellular bacteria, to the antibiotic rifampin is not solely due to the Leu-973 residue in the RNA polymerase β subunit.

Vibrio vulnificus poses an emerging threat as a human pathogen. While the incidence of human disease from V. vulnificus has historically been low, rising water temperatures are leading to an increase in human exposure across various latitudes. The severity of infections caused by V. vulnificus is particularly alarming, with most cases requiring hospitalization and a mortality rate of 35%. In this study, we investigate several strains of V. vulnificus isolated from the environment and find that their levels of pathogenicity vary. Interestingly, the genotypes of these strains do not align completely with previously identified markers of virulence.

The initial findings on bacterial diversity and geochemical data indicate that microbes enter the Winter Wonderland ice cave from the epikarst, carried by seasonal meltwater. The presence of these microbes in water, cryogenic cave carbonates (CCCs), and ice suggests they originate from the soil and are preserved differently depending on the sample type within the cave system. Notable differences exist between the water and CCCs, as well as observable potential cells or calcite spherules. These findings warrant further investigation into the possibility of biological mineralization in this system.

An example experiment using deoxyviolaceint-based transposon insertion vectors to transfect a target microbe. Differences in pigment production are easily screened for further downstream experiments.

Cover caption: The cover image is based on the Research Article Root nodules of red alder (Alnus rubra) and Sitka alder (Alnus viridis ssp. sinuata) are inhabited by taxonomically diverse cultivable microbial endophytes by Robyn Dove et al., https://doi.org/10.1002/mbo3.1422.

Image credit to Felisha Pooler.

G-1, a selective agonist of the G protein-coupled estrogen receptor (GPER), mitigates the pathogenesis mediated by alpha-hemolysin, a toxin produced by Staphylococcus aureus. It achieves this by reducing the surface display of the toxin's receptor, ADAM10. Our study, conducted on macrophage-like differentiated THP-1 cells, reveals that treatment with G-1 leads to a decrease in ATP release, a reduction in the activity of the caspase-1 enzyme, and a decrease in cell death following exposure to alpha-hemolysin.

Plants that host nitrogen-fixing symbionts in their root nodules play a significant role in both ecology and economy. However, the secondary members of these root nodule microbiomes have not been thoroughly studied. Our field survey conducted on Mount St. Helens revealed that both red Alder and Sitka Alder host a diverse range of cultivable microorganisms in their root nodules.

This study investigates the biogeographical patterns of bacterial communities in the gastrointestinal tract of Ampullaceana balthica snails compared with those in sediment and water. The findings indicate that substrate type significantly influences bacterial community composition, with distinct patterns observed in snail gastrointestinal tract communities. The research highlights the role of local water bacterial communities in colonizing the gastrointestinal tract, contributing to our understanding of host-associated bacterial biogeography.

The protein AgtB has a specific affinity for 5-aminovalerate. In contrast, both PA0602 and PA4985 show a strong preference for GABA, with secondary affinities for 5-aminovalerate and ethylenediamine. Despite these findings, there is no evidence to suggest that these solute-binding proteins—PA0602, PA4985, and AgtB—have any role in activating the AgtS and AruS sensor histidine kinases.

This study uses turbidimetric bioassays to detect antimicrobial activity in asymptomatic bacteriuria (ABU) isolates against uropathogenic E. coli (UPEC). The cell-free supernatant (CFS) from eight ABU isolates showed promising results. Notably, E. coli PUTS 58 and SK-106-1 demonstrated enhanced activity in artificial urine medium. The findings suggest a potential use of ABU bacteriocin-producers as prophylactics and therapeutics amidst rising antibiotic resistance.

In this study, we successfully cultivated the cable bacteria strain Electronema aureum GS on a newly developed synthetic sediment, marking the first instance of such cultivation on synthetic rather than natural sediment. The combination of this synthetic sediment and a specially designed sediment bioreactor enables reproducible cultivation of cable bacteria. This advancement paves the way for future investigations into the potential application of cable bacteria in bioprocess engineering.