Journal: Microbial Biotechnology

Article Title: Structured Promoter Variability in Epigenetically Regulated Operons Contributes to Surface Adaptation in Salmonella

doi: 10.1111/1751-7915.70312

Figure Lengend Snippet: The opvAB operon in the genus Salmonella . (a) Delimitation of the opvAB ‐containing DNA fragment acquired by horizontal gene transfer (HGT). Analysis of GC content of opvAB and neighbouring regions. The sequence of Salmonella enterica subsp. enterica serovar Typhimurium ATCC 14028 was analysed using SnapGene software. Diagram of GC content of the sequence located between opvA and yeiW genes. GC content suggests the boundary of the operon is located 220 nucleotides upstream of the opvA gene. The promoter‐proximal boundary of the HGT fragment is located 220 nucleotides upstream of opvA ATG. The diagram depicts the ribosome binding site, RBS (green), the −35 and −10 promoter modules (blue), the four GATCs (red) found in the upstream activating sequence (UAS) and the four OxyR binding sites, OBS A OBS B OBS C and OBS D (purple). (b) Assortment of the 992‐nucleotide sequence containing the opvAB operon in 5530 Salmonella genomes available in the NCBI database, classified by species and subspecies. Number of opvAB positive genomes among the sequences available at the NCBI database. A total of 824 genomes were annotated as S. enterica without subspecies‐level classification; among them, 344 contained the opvAB operon sequence. (c) Inter‐subspecies mutational landscape of the opvAB key regulatory elements across Salmonella enterica genomes classified by subspecies. Analysis includes mutations in the −35 and −10 promoter boxes, four GATC sites and four OxyR binding sites. Among the analysed genomes, 1710 correspond to subsp. enterica , 14 to subsp. arizonae , 20 to subsp. diarizonae and 18 to subsp. salamae . The reference sequence from strain ATCC 14028 is displayed below the heatmap. Each row represents a genome, and each column corresponds to a nucleotide position. OBS motifs are annotated following established consensus sequences, while invariant positions are shown in uppercase, degenerate positions (i.e., variable nucleotides) are shown in lowercase (Storz et al. ; Toledano et al. ). Nucleotide changes are represented by colours as follows: Substitutions (blue), insertions (green), deletions (red) and conserved positions (white).

Article Snippet: Unless otherwise noted, Salmonella enterica strains belong to serovar Typhimurium and are derived from the mouse‐virulent strain ATCC 14028.

Techniques: Sequencing, Software, Binding Assay

Journal: Microbial Biotechnology

Article Title: Structured Promoter Variability in Epigenetically Regulated Operons Contributes to Surface Adaptation in Salmonella

doi: 10.1111/1751-7915.70312

Figure Lengend Snippet: Intra‐subspecies mutational distribution in the regulatory region of the opvAB operon in Salmonella enterica subsp. enterica . (a) Localisation and distribution of mutations within the 220 nucleotides upstream of the opvA start codon, across S. enterica subsp. enterica genomes carrying between 1 and 8 mutations. Each row represents a genome, and each column corresponds to a nucleotide position. The nucleotide sequence of the ATCC 14028 strain used as reference is shown below the heatmap, with key regulatory elements such as GATC sites, OxyR binding sites (OBSs) and the −35 and −10 promoter boxes highlighted in colours. Nucleotides corresponding to conserved positions in the OBS consensus sequence are highlighted in green. Mutations are categorised as deletions (red), insertions (green) and substitutions (blue), while conserved nucleotides are represented in white. (b) Localisation and distribution of mutations within the regulatory region of opvAB in eight Salmonella strains collected in poultry farms. Each row represents one strain, and each column corresponds to a nucleotide position. The nucleotide sequence of the ATCC 14028 strain used as reference is shown below the heatmap, with key regulatory elements such as GATC sites, OxyR binding sites (OBSs) and the −35 and −10 promoter boxes highlighted in colours. Nucleotides corresponding to conserved positions in the OBS consensus sequence are highlighted in green. Mutations are categorised as deletions (red), insertions (green) and substitutions (blue), while conserved nucleotides are represented in white.

Article Snippet: Unless otherwise noted, Salmonella enterica strains belong to serovar Typhimurium and are derived from the mouse‐virulent strain ATCC 14028.

Techniques: Sequencing, Binding Assay

Journal: Microbial Biotechnology

Article Title: Structured Promoter Variability in Epigenetically Regulated Operons Contributes to Surface Adaptation in Salmonella

doi: 10.1111/1751-7915.70312

Figure Lengend Snippet: Intra‐subspecies mutational distribution in the regulatory region of the gtrABC operon in Salmonella enterica subsp. enterica . Localisation and distribution of mutations within the 220 nucleotides upstream of the gtrA start codon across S. enterica subsp. enterica genomes carrying between 1 and 8 mutations. Each row represents a genome, and each column corresponds to a nucleotide position. The nucleotide sequence of the ATCC 14028 strain used as reference is shown below the heatmap, with key regulatory elements such as GATC sites, OxyR binding sites (OBSs) and the −35 and −10 promoter boxes highlighted in colours (Broadbent et al. ). Nucleotides corresponding to conserved positions in the OBS consensus sequence are highlighted in green. Mutations are categorised as deletions (red), insertions (green) and substitutions (blue), while conserved nucleotides are represented in white.

Article Snippet: Unless otherwise noted, Salmonella enterica strains belong to serovar Typhimurium and are derived from the mouse‐virulent strain ATCC 14028.

Techniques: Sequencing, Binding Assay

Journal: Frontiers in Microbiology

Article Title: Emergence and characterization of a novel ST627-KL8 carbapenem-resistant Klebsiella pneumoniae lineage associated with ICU transmission in a tertiary hospital, China

doi: 10.3389/fmicb.2025.1723336

Figure Lengend Snippet: The mucoviscosity (A) , capsule quantification (B) , and serum resistance (C) of ST627-KL8 strains. (A) Mucoviscosity in three ST627-KL8 clinical strains, K. pneumoniae ATCC 43816 and K. pneumoniae ATCC 700603. The mucoviscosity of strains was determined by a semi-quantitative measurement. (B) Capsule uronic acid production in three ST627-KL8 clinical strains, K. pneumoniae ATCC 43816 and K. pneumoniae ATCC 700603. (C) The resistance of strains against human serum. The serum killing assays were performed by incubating three ST627-KL8 isolates, K. pneumoniae ATCC 43816 and K. pneumoniae ATCC 700603, with human serum for 1, 2, or 3 h at 37°C. Data are presented as mean ± SD derived from three separate experiments. One-way ANOVA with Dunnett’s test was used to analyze data, **** p < 0.0001. For panel (C) , **** p < 0.0001 and *** p < 0.001 indicated ST627-KL8 versus K. pneumoniae ATCC 43816, #### p < 0.0001 and ### p < 0.001 for ST627-KL8 versus K. pneumoniae ATCC 700603.

Article Snippet: The low-virulence strain K. pneumoniae ATCC 700603 exhibited a high survival rate of 96.7% (29/30 larvae), statistically comparable to that of the PBS control group (96.7%, 29/30).

Techniques: Derivative Assay

Journal: Frontiers in Microbiology

Article Title: Emergence and characterization of a novel ST627-KL8 carbapenem-resistant Klebsiella pneumoniae lineage associated with ICU transmission in a tertiary hospital, China

doi: 10.3389/fmicb.2025.1723336

Figure Lengend Snippet: Virulence assessment of three ST627-KL8 CRKP isolates in the G. mellonella infection model. Larvae were injected with PBS (negative control), reference strains K. pneumoniae ATCC 700603 (low-virulence control), K. pneumoniae ATCC 43816 (hypervirulent control), and three ST627-KL8 CRKP isolates (ZJG29565, ZJG30140, ZJG30146) separately. Survival was monitored over time ( n = 30 larvae per group). Survival curves were generated using the Kaplan–Meier method, and statistical significance between groups was determined by the Log-rank test. Data are representative of three independent experiments.

Article Snippet: The low-virulence strain K. pneumoniae ATCC 700603 exhibited a high survival rate of 96.7% (29/30 larvae), statistically comparable to that of the PBS control group (96.7%, 29/30).

Techniques: Infection, Injection, Negative Control, Control, Generated

Journal: Frontiers in Microbiology

Article Title: Emergence and characterization of a novel ST627-KL8 carbapenem-resistant Klebsiella pneumoniae lineage associated with ICU transmission in a tertiary hospital, China

doi: 10.3389/fmicb.2025.1723336

Figure Lengend Snippet: The mucoviscosity (A) , capsule quantification (B) , and serum resistance (C) of ST627-KL8 strains. (A) Mucoviscosity in three ST627-KL8 clinical strains, K. pneumoniae ATCC 43816 and K. pneumoniae ATCC 700603. The mucoviscosity of strains was determined by a semi-quantitative measurement. (B) Capsule uronic acid production in three ST627-KL8 clinical strains, K. pneumoniae ATCC 43816 and K. pneumoniae ATCC 700603. (C) The resistance of strains against human serum. The serum killing assays were performed by incubating three ST627-KL8 isolates, K. pneumoniae ATCC 43816 and K. pneumoniae ATCC 700603, with human serum for 1, 2, or 3 h at 37°C. Data are presented as mean ± SD derived from three separate experiments. One-way ANOVA with Dunnett’s test was used to analyze data, **** p < 0.0001. For panel (C) , **** p < 0.0001 and *** p < 0.001 indicated ST627-KL8 versus K. pneumoniae ATCC 43816, #### p < 0.0001 and ### p < 0.001 for ST627-KL8 versus K. pneumoniae ATCC 700603.

Article Snippet: In the Galleria mellonella model, ST627-KL8 exhibited intermediate virulence (66.7%–76.7% survival), between the hypervirulent K. pneumoniae ATCC 43816 strain (30.0%) and the low-virulence K. pneumoniae ATCC 700603 strain (96.7%).

Techniques: Derivative Assay

Journal: Frontiers in Microbiology

Article Title: Emergence and characterization of a novel ST627-KL8 carbapenem-resistant Klebsiella pneumoniae lineage associated with ICU transmission in a tertiary hospital, China

doi: 10.3389/fmicb.2025.1723336

Figure Lengend Snippet: Virulence assessment of three ST627-KL8 CRKP isolates in the G. mellonella infection model. Larvae were injected with PBS (negative control), reference strains K. pneumoniae ATCC 700603 (low-virulence control), K. pneumoniae ATCC 43816 (hypervirulent control), and three ST627-KL8 CRKP isolates (ZJG29565, ZJG30140, ZJG30146) separately. Survival was monitored over time ( n = 30 larvae per group). Survival curves were generated using the Kaplan–Meier method, and statistical significance between groups was determined by the Log-rank test. Data are representative of three independent experiments.

Article Snippet: In the Galleria mellonella model, ST627-KL8 exhibited intermediate virulence (66.7%–76.7% survival), between the hypervirulent K. pneumoniae ATCC 43816 strain (30.0%) and the low-virulence K. pneumoniae ATCC 700603 strain (96.7%).

Techniques: Infection, Injection, Negative Control, Control, Generated

Journal: Microbiology Spectrum

Article Title: Epidemiological and functional insights into iroBCDN loss in ST11 carbapenem-resistant hypervirulent Klebsiella pneumoniae

doi: 10.1128/spectrum.02479-25

Figure Lengend Snippet: Virulence assessment of the 46 CR-hvKP clinical isolates using the Galleria mellonella infection model. Survival curves of the larvae infected with CR-hvKP strains are shown in comparison with the high-virulence control strain NTUH-K2044, low-virulence control strain ATCC 700603, and PBS control. Statistical significance was determined by the log-rank (Mantel-Cox) test.

Article Snippet: In contrast, the high-virulence control strain NTUH-K2044 showed a slightly lower LDH release (1.33 ± 0.05 μmol/L), while the low-virulence strain ATCC 700603 exhibited markedly reduced cytotoxicity (0.35 ± 0.03 μmol/L) with a significant difference compared to all other groups ( P < 0.0001).

Techniques: Infection, Comparison, Control

Journal: Microbial Biotechnology

Article Title: Exploiting Paraphaeosphaeria minitans and Its Antifungal Metabolites as Bio‐Fungicides for Eco‐Friendly Management of Head Rot Disease in Cabbage

doi: 10.1111/1751-7915.70309

Figure Lengend Snippet: Scanning electron micrographs showing structural components of S. sclerotiorum (TNAU‐SS‐5) sclerotia in the absence and presence of P. minitans (TNAU‐CM 1). (a) Healthy sclerotium with intact rind (1500×; scale bar, 50 μm). (b) Distorted sclerotium colonised by P. minitans , with pycnidiospores visible on the surface (120×; scale bar, 500 μm; red arrows, pycnidiospores). (c) Pycnidiospores of P. minitans covering S. sclerotiorum hyphae (2000×; scale bar, 50 μm; red arrows, pycnidiospores; yellow arrows, S. sclerotiorum hyphae). (d) Aggregate of pycnidiospores on S. sclerotiorum hyphae (2000×; scale bar, 10 μm; red arrows, pycnidiospores; yellow arrows, S. sclerotiorum hyphae). (e) P. minitans hyphae coiling around and distorting S. sclerotiorum hyphae (5000×; scale bar, 5 μm; yellow arrows, S. sclerotiorum hyphae; red arrows, P. minitans hyphae). (f) Appressorium‐like structures formed by P. minitans at the sclerotial surface (5000×; scale bar, 10 μm; arrows indicate appressorium‐like structures).

Article Snippet: The highly virulent S. sclerotiorum strain TNAU‐SS‐5 (National Centre for Biotechnology Information [NCBI] accession number MZ379266.1 ), maintained at the Department of Plant Pathology, Tamil Nadu Agricultural University (TNAU), Coimbatore, Tamil Nadu, India, was used for this study (Ruppavalli et al. ; Venkatesan et al. ).

Techniques: