NAD+ · research summary

Mechanistic insights into the antimicrobial activity of a novel essential oil blend against Bacillus subtilis using RNA sequencing.

AIMS microbiology · 2026. Summary drawn from the study's full text. Each statement is followed by the exact sentence it comes from. This is a research summary, not medical advice.

Study type

In vitro transcriptomic analysis of bacterial response to an essential oil blend
“This study investigated the global transcriptional response of Bacillus subtilis to a novel essential oil blend (EOB1) composed of garlic, lemongrass, cumin, lavender, and nutmeg.”

Subjects

Bacillus subtilis subsp. subtilis str. 168
“B. subtilis subsp. subtilis str. 168, a Gram-positive bacterium, was evaluated for its susceptibility to the essential oil blend.”

Sample size

Three independent biological replicates per group
“To examine how B. subtilis responds at the transcriptional level to sub-MIC essential oil treatments, three independent biological replicates (n = 3 per group) were prepared for the treatment and the untreated control.”

Duration

60 minutes of exposure for transcriptomic analysis
“At that stage, each culture was treated with the sub-MIC essential oil fraction and incubated for an additional 60 minutes to permit transcriptional changes to occur.”

Reported findings

Exposure to the essential oil blend resulted in widespread transcriptional changes with 1682 differentially expressed genes after filtering
“After filtering at a false discovery rate (FDR) of <0.05 and an absolute log2 fold change of >1, 1682 differentially expressed genes remained, comprising 981 upregulated and 701 downregulated genes.”
Principal component analysis showed clear separation between treated and control samples, with the first component explaining 97% of variance
“Principal component analysis showed clear separation between treated and control samples, with the first principal component explaining 97% of the total variance, indicating a strong global transcriptional effect of EOB1 on bacterial gene expression.”
Gene ontology analysis identified significant overrepresentation of stress response, fatty acid beta-oxidation, and oxidoreductase activity
“Gene Ontology enrichment analysis further supported these patterns, with significant overrepresentation of fatty acid β-oxidation, oxidoreductase activity acting on nicotinamide adenine dinucleotide phosphate (NAD(P)H), stress response pathways, amino acid biosynthetic processes, and cytoplasmic components.”

Limitations stated by the authors

Study limited to a single species, single time point, and single concentration; mechanisms inferred from transcriptomics without direct biochemical validation; chemical composition of the aqueous fraction was not recharacterized
“The transcriptional response was examined in a single bacterial species (B. subtilis), at a single exposure time, and at one subinhibitory concentration, so the results represent only a snapshot of what is likely a dynamic, dose-dependent response and may not generalize to other bacteria.”

Source: PubMed 42859438 · DOI 10.3934/microbiol.2026023 · all study summaries

Reported findings

Exposure to the essential oil blend resulted in widespread transcriptional changes with 1682 differentially expressed genes after filtering

“After filtering at a false discovery rate (FDR) of <0.05 and an absolute log2 fold change of >1, 1682 differentially expressed genes remained, comprising 981 upregulated and 701 downregulated genes.”

Principal component analysis showed clear separation between treated and control samples, with the first component explaining 97% of variance

“Principal component analysis showed clear separation between treated and control samples, with the first principal component explaining 97% of the total variance, indicating a strong global transcriptional effect of EOB1 on bacterial gene expression.”

Gene ontology analysis identified significant overrepresentation of stress response, fatty acid beta-oxidation, and oxidoreductase activity

“Gene Ontology enrichment analysis further supported these patterns, with significant overrepresentation of fatty acid β-oxidation, oxidoreductase activity acting on nicotinamide adenine dinucleotide phosphate (NAD(P)H), stress response pathways, amino acid biosynthetic processes, and cytoplasmic components.”

Limitations stated by the authors

Study limited to a single species, single time point, and single concentration; mechanisms inferred from transcriptomics without direct biochemical validation; chemical composition of the aqueous fraction was not recharacterized

“The transcriptional response was examined in a single bacterial species (B. subtilis), at a single exposure time, and at one subinhibitory concentration, so the results represent only a snapshot of what is likely a dynamic, dose-dependent response and may not generalize to other bacteria.”