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Tobacco leaf contains antibacterial secondary metabolite compounds, such as phenol, alkaloids, and essential oils. This study compares the potential antibacterial effects of Indonesian tobacco leaf extracted using the heat reflux method (producing an extract) and pyrolysis method (providing a bio-oil). The tobacco leaf extract was challenged against Staphylococcus aureus ATCC 25923, Enterococcus faecalis ATCC 29212, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853. The bio-oil from the pyrolysis method showed inhibitory Kirby Bauer zones higher than those of the extract from heat reflux method, with the maximum results in the pyrolysis method indicating zones of 6.35 mm (S. aureus), 5.90 mm (E. faecalis), 3.97 mm (E. coli), and 5.025 mm (P. aeruginosa). Further study analyzed the effectiveness of the disc and well diffusion antibacterial test methods for measuring the antibacterial effect of bio-oils against Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 27853. The bio-oil used in the well diffusion test method showed the most significant antibacterial effectiveness. It showed the biggest inhibition zone, with a maximum of 11.65 mm and 8.90 mm for E. coli and P. aeruginosa. Our results showed Nicotiana tabacum var. Virginia Bio Oil from Ponorogo (Indonesia) is a strong potential antimicrobial, especially using well diffusion test. [ABSTRACT FROM AUTHOR]

The opportunistic human pathogen Pseudomonas aeruginosa exhibits great resistance to antibiotics; so, new therapeutic agents are urgently needed. Since polyamines levels are incremented in infected tissues, we explored whether the formation of a toxic aldehyde in polyamines degradation can be exploited in combating infection. We cloned the gene encoding the only aminoaldehyde dehydrogenase involved in P. aeruginosa polyamines‐degradation routes, PaPauC, overexpressed this enzyme, and found that it oxidizes 3‐aminopropionaldehyde (APAL) and 3‐glutamyl‐3‐aminopropionaldehyde (GluAPAL) − produced in spermine (Spm), spermidine (Spd), and diaminopropane (Dap) degradation, as well as 4‐aminobutyraldehyde (ABAL) and 4‐glutamyl‐4‐aminobutyraldehyde (GluABAL) − formed in putrescine (Put) degradation. As the catalytic efficiency of PaPauC with APAL was 30‐times lower than with GluAPAL, and GluAPAL is predominantly formed, APAL will be poorly oxidized 'in vivo'. We found polyamines‐induced increases in the PaPauC activity of cell crude‐extracts and in the expression of the PapauC gene that were diminished by glucose. Spm, Spd, or Dap, but not Put, were toxic to P. aeruginosa even in the presence of other carbon and nitrogen sources, particularly to a strain with the PapauC gene disrupted. APAL, but not GluAPAL, was highly toxic even to wild‐type cells, suggesting that its accumulation, particularly in the absence of, or low, PaPauC activity is responsible for the toxicity of Spm, Spd, and Dap. Our results shed light on the toxicity mechanism of these three polyamines and strongly support the critical role of PaPauC in this toxicity. Thus, PaPauC emerges as a novel potential drug target whose inhibition might help in combating infection by this important pathogen. [ABSTRACT FROM AUTHOR]

The application of nanotechnology has brought about advancements in environmental and medical applications. Recently, zinc oxide nanoparticle (ZnO NP) is commonly used to treat a wide range of bacterial and fungal skin infections due to its antimicrobial property. This investigation was intended to study the antimicrobial effect of ZnO NP on Pseudomonas aeruginosa by testing the bacterial inhibition and the morphological damages caused by ZnO NP to P. aeruginosa. The results of this study exhibited a typical dose-dependent and significant (p < 0:05) inhibition of the growth of P. aeruginosa treated with 5 to 150 µg/mL of ZnO NP. The polysaccharides and polypeptides from P. aeruginosa cell wall were found to be associated with the attachment of ZnO NPs to bacterial cells as illustrated in the Fourier Transform Infrared (FTIR) spectrum. Furthermore, Scanning Electron Microscopy (SEM) images displayed the surface attachment of ZnO NPs on bacteria and the morphological changes, such as disrupted cell wall integrity, cell bending, and cell distortion, as a result of ZnO NPs interaction on the cell wall of P. aeruginosa. [ABSTRACT FROM AUTHOR]