Characterization of the Bactericidal Effects of Sodium Nitroprusside and Other Pentacyanonitrosyl Complexes on the Food Spoilage BacteriumClostridium sporogenes

Abstract

The potent bactericidal activity of sodium nitroprusside {SNP; Na2[Fe(CN)5(NO)]} towards Clostridium sporogenes has been investigated. SNP inhibited cell growth in the concentration range of 10 to 40 μM. Concentrations above 80 μM caused irreversible loss of cell viability and cell lysis. Inhibition of cell growth was similar in complex and in defined media. SNP was found to be unreactive towards individual components of the defined medium, with the exception of cysteine. The chemical characteristics responsible for the potency of SNP were investigated by synthesizing analogs of SNP in which the Fe was replaced by different metals. The inhibitory potency of the pentacyanonitrosyl complexes decreased in the order Fe > Cr > V, which correlates with N-O stretching frequency (vNO). In contrast, the Ru complex which had avNO comparable to that of Fe was a poor inhibitor. Electron paramagnetic resonance spectroscopy showed that SNP was rapidly reduced to the paramagnetic Fe(I) compound [Fe(CN)4(NO)]2− on contact with cells. Analysis of fractions from SNP-treated cells showed 90% oxidation of thiols in the cell walls compared with those in control cells. The toxicity of SNP involves S-nitrosation and reduction, the lack of toxicity of the Ru analog being consistent with the fact that it has poor reactivity towards thiols. When C. sporogenes cells were exposed to sublethal concentrations of SNP and viewed under the electron microscope, they showed blisters on the surface. These results point to the cell wall surface as a primary point of attack of the nitrosyl complex.

Involvement of Sodium Nitroprusside (SNP) in the Mechanism That Delays Stem Bending of Different Gerbera Cultivars

“…An association of delayed stem bending and low bacterial concentration has been reported ( Perik et al, 2014 ). In addition, this finding supports the results of previous reports describing the bactericidal effects of SNP, which is most commonly observed in the xylem of cut flowers ( Joannou et al, 1998 ; Seabra et al, 2010 ; Martínez-Ruiz et al, 2011 ; Cardozo et al, 2014 ). Many researchers reported that sliver nitrate and sliver nanoparticles, which are primarily known as ethylene inhibitors and antimicrobial agents, delayed stem bending of gerbera flowers ( Nair et al, 2003 ; Meman and Dabhi, 2006 ; Prashanth and Chandrasekhar, 2007 ; Liu et al, 2009 ; Solgi et al, 2009 ).…”

“…Xylem blockage at the stem surface, due to bacterial growth, has been reported in previous studies ( van Doorn, 1997 ; Ranwala and Miller, 2009 ). In the present study, less xylem blockage in the SNP treatments would be expected to be due to SNP’s antibacterial activity, which has been previously reported ( Joannou et al, 1998 ; Martínez-Ruiz et al, 2011 ; Cardozo et al, 2014 ).…”

“…Their vase lives were extended by SNP inhibiting ethylene production and promoting antioxidant activity. In addition, SNP inhibited the growth of bacteria, such as Clostridium sporogenes, Staphylococcus aureus , and Escherichia coli , which are the most commonly observed species in the xylem of cut flowers ( Joannou et al, 1998 ; Seabra et al, 2010 ; Martínez-Ruiz et al, 2011 ; Cardozo et al, 2014 ). It also positively affected lignification ( Böhm et al, 2010 ).…”

“…Indeed, SNP has improved the vase life of various cut flowers, such as rose, gladiolus, and carnation ( Zeng et al, 2011 ; Liao et al, 2013 ; Dwivedi et al, 2016 ; Naing et al, 2017 ), by downregulating ethylene biosynthesis and senescence-associated genes and by enhancing antioxidant activity. In addition, SNP has shown antibacterial activity by inhibiting the growth of Clostridium sporogenes, Staphylococcus aureus , and Escherichia coli , which are the most commonly observed bacteria in the xylem of cut flowers ( Joannou et al, 1998 ; Seabra et al, 2010 ; Martínez-Ruiz et al, 2011 ; Cardozo et al, 2014 ). Nitric oxide also positively affected lignification ( Böhm et al, 2010 ).…”

Synergy of Sodium Nitroprusside and Nitrate in Inhibiting the Activity of Sulfate Reducing Bacteria in Oil-Containing Bioreactors

“…2H 2 O; SNP) is used as a low cost, effective, fast-acting and safe vasodilating drug for treatment of pulmonary hypertension ( Koslyk et al, 2015 ; Lim and Zaphiriou, 2016 ). Although it has not been used as a biocide, the bactericidal or biofilm dispersal effect of SNP has been reported for Pseudomonas aeruginosa ( Barraud et al, 2006 ; Barnes et al, 2013 ), Clostridium sporogenes ( Joannou et al, 1998 ), and Bacillus subtilis ( Moore et al, 2004 ). The bactericidal effect of SNP is suggested to be due to the release of highly reactive nitric oxide (NO) ( Barraud et al, 2006 ; Chua et al, 2014 ).…”