Applied Microbiology

Chemical fungicides play a key role in protecting crops, but their use can result in environmental problems. We tested a novel fungicide, composed of endophytic microorganisms, for its effect on wheat yield, grain quality, plant development, and the rhizosphere microbiome, assessed by 16S and ITS metabarcoding. The fungicide increased the grain yield, the effect being similar to a well-known commercial bacterial fungicide, without affecting its quality. Ascomycota, Zygomycota and Mucoromycota together comprised 80% of the mycobiome. Mucoromycota/Mucoromycetes/Rhizopodaceae/Rhizopus arrhizus were significantly decreased. The dominant (≥10%) bacterial phyla were Pseudomonadota, Acidobacteriota, Bacteroidota and Actinomycetota, but their fungicide-related differences were small or random. Different modes of fungicide application (seeds only, seeds plus one or two foliar applications) had no effect on wheat characteristics. Neither of the fungicide’s agents (Raoultella ornithinolytica and Pantoea allii) were found in the rhizosphere. The changes in the mycobiome seemed more pronounced than in the bacteriobiome. The proposed preparation is concluded to have good prospects as a fungicide. However, the low species/strain resolution of the DNA metabarcoding did not allow us to fully interpret shifts in the microbiome diversity, both agronomically and environmentally. These aspects need more comprehensive investigation, using methodology with higher species resolution.

The gut microbiome plays a vital role in metabolism and can be significantly influenced by body mass index (BMI). This study investigated the variations in gut microbial composition and function across different BMI categories by analyzing 16S rRNA sequencing data of 126 stool samples. While our analysis of microbial diversity did not reveal significant differences among BMI groups, a differential abundance analysis identified specific bacterial genera associated with BMI status. Notably, Lachnospira, Lactobacillus, and Roseburia were enriched in non-obese individuals, while Phascolarctobacterium showed greater abundance in obese subjects. Functional profiling utilizing PICRUSt2 and DESeq2 revealed fifteen KEGG pathways that exhibited significant alterations across varying BMI groups. Notably, several of these pathways were associated with short-chain fatty acid (SCFA)-producing taxa, including Lactobacillales and Tannerellaceae. Additionally, covariance network analysis identified the microbial genera Alistipes and Bilophila as central participants in multiple metabolic pathways, particularly those associated with steroid biosynthesis and pathogenic Escherichia coli, which showed a notable enrichment in individuals with obesity. These findings suggest that BMI influences the composition and metabolic potential of the gut microbiome, highlighting the importance of functional profiling to better understand the mechanisms underlying obesity.

Lactobacillus acidophilus is a widely researched probiotic bacterium with broad applications in health and biotechnology; however, its protoplast formation has not been extensively investigated. This study aimed to optimize conditions for L. acidophilus protoplast formation. Freeze-dried cells were suspended in 20 mM HEPES buffer (pH 7) supplemented with sucrose (1.0 M, 1.5 M, and 2.0 M) to induce hyperosmotic conditions, yielding a final cell density of 10⁸ cells/mL. The suspensions were treated with 125 µg/mL lysozyme and incubated at 37 °C for 30 min, 1 h, or 2 h. Prior to enzymatic treatment, the buffer, lysozyme, and cell suspensions were equilibrated at either 22 °C (room temperature) or 37 °C. Phase contrast microscopy was used to evaluate protoplast formation across all treatment combinations, and a three-way ANOVA was conducted to assess the effects of buffer molarity, incubation time, and temperature. Protoplasts are valuable tools for genetic manipulation, cell fusion, and cell wall studies, yet optimized protocols for their generation in L. acidophilus are lacking. The highest protoplast yield with minimal lysis was observed under 2.0 M sucrose conditions after 2 h of incubation, particularly when all components were equilibrated at 37 °C. Prolonged lysozyme exposure increased lysis, especially at lower buffer molarities. Elevated buffer molarity conferred a protective effect by maintaining cell integrity during enzymatic digestion. These findings highlight the importance of osmotic strength and thermal equilibration in optimizing protoplast formation and provide a reproducible framework for controlled enzymatic treatments in L. acidophilus.