e coli ca434 e coli hb101 harboring plasmid r702 guo  (ATCC)

Journal: Langmuir

Article Title: Silver Nanoparticles Templated by the M13 Phage Exhibit High Antibacterial Activity against Gram-Negative Pathogens and a Reduced Rate of Bacterial Resistance In Vitro

doi: 10.1021/acs.langmuir.5c03695

Figure Lengend Snippet: Effect of AgM13 1d , AgM13 2h , and AgNP comm nanoparticles on the growth of various bacterial strains: (a) E. coli ER2738, (c) E. coli DH5α, (e) P. aeruginosa , and (g) V. cholerae following treatment with AgNPs at Ag concentrations of 0.04, 0.1, and 0.2 μg mL –1 (Ag concentration determined by ICP-MS). Data are presented as means ± SEM ( n = 3) biologically independent replicates. Areas under the curve (AUC), representing bacterial growth potential, are shown for (b) E. coli ER2738, (d) E. coli DH5α, (f) P. aeruginosa , and (h) V. cholerae . AUC values are expressed as the mean ± SD. Statistical significance was assessed using one-way analysis of variance (ANOVA) for all groups of the same species, followed by Tukey’s test with false discovery rate (FDR) post hoc correction ( n = 3); p values compared to the control are indicated in the corresponding graphs.

Article Snippet: The Y21A mutant was constructed using the Q5 Site-Directed Mutagenesis Kit (New England Biolabs, USA), according to the manufacturer’s instructions, and transformed into Mix & Go Competent E. coli Cells (Zymo Research, USA) using kanamycin selection.

Techniques: Concentration Assay, Control

Journal: Langmuir

Article Title: Silver Nanoparticles Templated by the M13 Phage Exhibit High Antibacterial Activity against Gram-Negative Pathogens and a Reduced Rate of Bacterial Resistance In Vitro

doi: 10.1021/acs.langmuir.5c03695

Figure Lengend Snippet: Influence of AgM13 1d , AgM13 2h , and AgNP comm nanoparticles on E. coli biofilms. (a–c) Quantification of biofilm biomass by the crystal violet assay for three different E. coli strains. The absorbance at 520 nm reflects the extent of biofilm formation following exposure to different AgNP formulations. Data are expressed as the mean ± SD ( n = 3). Statistical significance was assessed using one-way ANOVA for groups of the same species, followed by Tukey’s test with false discovery rate (FDR) post hoc correction ( n = 3); p values for comparison to the control are indicated in the corresponding graphs. (d) Confocal laser scanning microscopy (CLSM) maximum projection images of E. coli ER2738 biofilms treated with various silver nanoparticles, stained with SYTO 9 and propidium iodide (PI). SYTO 9 (green fluorescence) indicates viable cells, while PI (red fluorescence) indicates compromised membranes, suggesting dead cells. (e) Three-dimensional reconstructions of corresponding biofilms showing the spatial distribution of live (green) and dead (red) cells following nanoparticle treatments as labeled.

Article Snippet: The Y21A mutant was constructed using the Q5 Site-Directed Mutagenesis Kit (New England Biolabs, USA), according to the manufacturer’s instructions, and transformed into Mix & Go Competent E. coli Cells (Zymo Research, USA) using kanamycin selection.

Techniques: Crystal Violet Assay, Comparison, Control, Confocal Laser Scanning Microscopy, Staining, Fluorescence, Labeling

Journal: Langmuir

Article Title: Silver Nanoparticles Templated by the M13 Phage Exhibit High Antibacterial Activity against Gram-Negative Pathogens and a Reduced Rate of Bacterial Resistance In Vitro

doi: 10.1021/acs.langmuir.5c03695

Figure Lengend Snippet: Bactericidal activity and bacterial resistance to AgM13 1d . (a) E. coli culture was grown to midexponential phase, and then AgM13 1d nanomaterial was added. Growth without AgM13 1d (black curve) or with different concentrations of AgM13 1d (red curves) was monitored by OD 600 . The concentration of AgM13 1d is shown on the right side in micrograms per milliliter. (b) End point samples were plated for the control (no AgM13 1d ), 0.2 μg mL –1 AgM13 1d , or 0.6 μg mL –1 AgM13 1d , to count colony-forming units (CFUs). No CFUs were observed at 0.6 μg mL –1 AgM13 1d , consistent with the observed decrease in OD 600 . (c) The E. coli culture was propagated over 15 rounds of serial passage in the presence of AgM13 1d (red), AgM13 2h (blue), or commercially purchased AgNPs (yellow). The minimum inhibitory concentration (MIC) was determined after each round, and the development of resistance was monitored by an increase in MIC. Commercial AgNPs show a high starting MIC and a 2-fold increase in MIC every two or three rounds. Black dots indicate the MIC above the detection range (>40 μg mL –1 ) for AgNP comm ; the MIC after round 15 was determined to be 120 μg mL –1 . In contrast, AgM13 1d and AgM13 2h exhibit low starting MICs and a 2-fold increase in MIC after eight rounds.

Article Snippet: The Y21A mutant was constructed using the Q5 Site-Directed Mutagenesis Kit (New England Biolabs, USA), according to the manufacturer’s instructions, and transformed into Mix & Go Competent E. coli Cells (Zymo Research, USA) using kanamycin selection.

Techniques: Activity Assay, Concentration Assay, Control

Journal: Langmuir

Article Title: Silver Nanoparticles Templated by the M13 Phage Exhibit High Antibacterial Activity against Gram-Negative Pathogens and a Reduced Rate of Bacterial Resistance In Vitro

doi: 10.1021/acs.langmuir.5c03695

Figure Lengend Snippet: AgNP comm -M13 and acid-digested AgM13 1d . (a) TEM micrographs showing the networked structure of nanomaterial (AgNP comm -M13) made from commercially purchased AgNPs and M13. (b) AgNP comm -M13 did not exhibit substantial antibacterial activity compared to AgM13 1d and AgM13 2h at the same concentration (0.2 μg mL –1 Ag) on E. coli ER2738. (c) TEM micrographs of acid-digested AgM13 1d indicate a loss of phage structures and the presence of aggregates of silver nanoparticles and amorphous organic matter. (d) Acid-digested AgM13 1d showed antibacterial activity with a modest decrease in potency on E. coli ER2738, as digestion caused a 4–6 h decrease in lag time compared to undigested AgM13 1d at the same concentration. No nanomaterial was added to the control.

Article Snippet: The Y21A mutant was constructed using the Q5 Site-Directed Mutagenesis Kit (New England Biolabs, USA), according to the manufacturer’s instructions, and transformed into Mix & Go Competent E. coli Cells (Zymo Research, USA) using kanamycin selection.

Techniques: Activity Assay, Concentration Assay, Control

Journal: Applied and Environmental Microbiology

Article Title: Indole-3-acetic acid (IAA) protects Azospirillum brasilense from indole-induced stress

doi: 10.1128/aem.02384-24

Figure Lengend Snippet: Strains and plasmids used in this study ^a

Article Snippet: E. coli HB101 , Host strain for pRK2013 , ATCC 33694.

Techniques: Plasmid Preparation, Cloning, Mutagenesis, Activity Assay, Gene Knock-In, Expressing