MicrobiologyOpen

This study has contributed to extending the general knowledge of the CRISPR–Cas systems, particularly in Serratia, a ubiquitous genus detected in different environments.

Here we report on the microbiome of frost flowers sampled during the winter and polar night in the Barents Sea. There was a distinct difference in community profile between the extracted DNA and RNA, but both were dominated by members of the SAR11 clade (78% relative abundance and 41.5% relative activity). The data further suggested high abundance and activity by Cand. Nitrosopumilus, Nitrospinia, and Nitrosomonas, indicating that sulfur and nitrogen cycling are likely the major metabolism in these ephemeral structures.

ParABS (Soj-Spo0J) systems and SMC complexes are critical mediators of chromosome dynamics in a range of bacteria. In this commentary, I review the roles of these systems in Bacillus subtilis, as well as discuss a recent study that implicates a monomeric variant of ParA/Soj as a novel regulator of SMC release and redistribution after loading onto the DNA, a process that is critical for chromosome reorganization during axial filament formation in early sporulation.

Bacteria can persist in the hospital environment inside dry biofilms which grow on inanimate surfaces surrounding the patients. We developed a new method to produce dry-surface biofilms using the spraying of enriched artificial saliva which mimics the dispersion of respiratory secretions. The method created dehydrated biofilms of methicillin resistant Staphylococcus aureus and Enterobacteria under real-world conditions.

The pathogenicity of Candida albicans is associated with the production of virulence factors such as extracellular hydrolytic enzymes and toxins. The results reported here demonstrate that the activity of secreted hydrolytic enzymes, in particular proteases, lipases, and hemolysins, is generally dependent on pH and is potentially associated with the clinical origin of C. albicans isolates.

Here we describe an in-house bead array targeting antimicrobial resistance (AMR) genes of Gram-positive bacteria and allowing their rapid detection all at once at reduced costs. A total of 27/41 AMR probes targeting genes frequently associated with resistance tested positive on a collection of 124 enterococci and 62 staphylococci isolated from healthy livestock animals. The array detected AMR genes associated with phenotypic resistance for 93% and 89.2% of the individual resistant phenotypes in enterococci and staphylococci, respectively.

In this study, adaptive laboratory evolution (ALE) was performed for over 300 days using consecutive 0.5°C temperature increases in a constant temperature incubator to attain greater thermal tolerance in the industrially relevant diatom Nitzschia inconspicua str. Hildebrandi. The adapted strain was able to grow at a constant temperature of 37.5°C; whereas this constant temperature was lethal to the parental control, which had an upper-temperature boundary of 35.5°C before adaptive evolution. This ALE method demonstrates the development of enhanced industrial algal strains without the production of genetically modified organisms.

Using whole genome sequencing of Mycobacterium bovis strains collected in two distinct areas of France with an evolutionary model, we showed that the role of host species in the circulation of the pathogen differed between both areas. While wild boars appeared to play the role of an intermediary between badgers and cattle in both areas, the role of badgers differed. Our results suggest that the transition pattern depends on ecological, landscape, and anthropic factors.

A Burkholderia cenocepacia universal stress protein encoded on the BCAM0276 gene (USP76) which is upregulated in chronic infection in people with cystic fibrosis (CF) and by hypoxia, is involved in attachment to human epithelial cells. It is required for growth in conditions associated with the CF lung, including acidic conditions and oxidative stress. Survival of usp76 deletion mutant was impaired in monocyte-derived macrophages from CF patients, suggesting it is involved in bacterial survival within macrophages, a hallmark of Burkholderia infection.

DNA replication, chromosome segregation, synthesis of the septal cell wall, and cytokinesis occur concomitantly in staphylococci. The processes are tightly coordinated temporally and spatially.

In this study, we assessed the composition and establishment of the microbiome of insect eggs using the Southern green stinkbug Nezara viridula (Hemiptera: Pentatomidae) as a study object. Our results show that the egg-associated bacterial microbiome is species-poor and dominated by a few symbionts, particularly the species-specific obligate Pantoea-like symbiont.

We applied machine learning techniques to Raman and absorption spectra to determine the concentration of samples containing viral particles (measles, mumps, rubella, and varicella-zoster viruses). We proposed two different networks to jointly use the Raman and absorption spectra, where our results demonstrated that concatenating the Raman and absorption data increases the prediction accuracy compared to using either Raman or absorption spectrum alone. Ultimately we were able to make predictions with accuracies as high as 95%.

The diacylglycerol acyltransferase (DGAT) enzymes catalyze the final step of the triacylglycerol biosynthesis by esterification of a fatty acyl moiety to a diacylglycerol. Murine and human DGAT2 were overexpressed in the strains of oleaginous yeast Yarrowia lipolytica deleted for all DGAT activities. Heterologous DGAT functionality was validated and response specificity to known DGAT inhibitors was evaluated. This work provides proof of principle for using these strains as a screening system for libraries of molecules to discover new inhibitors or activators of these enzymes of particular therapeutic interest.

Pseudomonas fluorescens produces compounds that increase plant growth, biocontrol, and adaptation to stress. Antagonistic effects of these strains against nematode Meloidogyne javanica were assessed in vitro and in vivo in tomato plants. Results suggest that P. fluorescens L124 is an effective plant growth promoter of tomato plants and P. fluorescens L321 was capable of M. javanica suppression. In an agricultural context, pretreating seeds and applying successional bacterial drenches would encourage positive plant bacterial interactions and increase antagonistic effects against M. javanica.

In recent years, the severity of some outbreaks of food-borne illness ascribed to Escherichia coli has been recognized as due to enhanced virulence brought about by altered genetic characteristics of the implicated pathovars. Herein, we report the isolation of a strain of E. coli possessing a virulence factor normally associated with gastrointestinal infections by Salmonella or Citrobacter. We further provide a detailed examination of the extent and distribution of the tetrathionate reductase genes within strains of E. coli, Shigella flexneri, and Shigella sonnei deposited in Genbank.

The production method of spores significantly influences the resistance of spores used as bioindicators (BI) in the validation of sterilization of packaging material surfaces in aseptic food manufacturing. Therefore, the standardization of the spore production method represents an important and desirable goal in industrial BI production to ensure reliable validation test results. A one-step manufacturing process was investigated in this work to reduce production complexity. Compared to the recommended two-step manufacturing process, almost 10-fold higher yields can be realized.

The whole genome of Chromohalobacter canadensis 85B was sequenced and its genome-scale metabolic model was reconstructed and validated, enabling a better understanding of its metabolism. We show that C. canadensis is a metabolically versatile organism with many features for stress and osmotic adaptation, including pathways for compatible solute and polyhydroxybutyrate (PHB) synthesis. The model reveals the ability to grow on several carbon sources in minimal medium, and produce PHBs and compatible solutes such as ectoine, 5-hydroxyectoine, and betaine.