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Studies with bioengineered Nisin peptides highlight the broad-spectrum potency of Nisin V.

Field D, Quigley L, O'Connor PM, Rea MC, Daly K, Cotter PD, Hill C, Ross RP - Microb Biotechnol (2010)

Bottom Line: In contrast, Nisin V displayed increased potency against all targets tested including hVISA strains and the hyper-virulent Clostridium difficile ribotype 027 and against important food pathogens such as Listeria monocytogenes and Bacillus cereus.Significantly, this enhanced activity was validated in a model food system against L. monocytogenes.We conclude that Nisin V possesses significant potential as a novel preservative or chemotherapeutic compound.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology, University College Cork, Cork, Ireland.

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Related in: MedlinePlus

IVIS imaging of the kill effect of Nisin peptides (7.5 mg l−1) against L. monocytogenes F2365lux in frankfurter meat over a 1 h exposure period. The top row depicits the image at time 0 (T0). The bottom row depicts the survival of L. monocytogenes F2365lux after 1 h (T1). The data points represent the corresponding RLU values for images. Rel % Surv figures refer to percentage survival of F2365lux as determined by CFU counts after 1 h (T1) where WT Nisin A = 100%.
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f3: IVIS imaging of the kill effect of Nisin peptides (7.5 mg l−1) against L. monocytogenes F2365lux in frankfurter meat over a 1 h exposure period. The top row depicits the image at time 0 (T0). The bottom row depicts the survival of L. monocytogenes F2365lux after 1 h (T1). The data points represent the corresponding RLU values for images. Rel % Surv figures refer to percentage survival of F2365lux as determined by CFU counts after 1 h (T1) where WT Nisin A = 100%.

Mentions: Having established the potency of Nisin V against L. monocytogenes using a variety of laboratory‐based assays, we sought to determine whether this enhanced effectiveness could be translated to a food matrix. This was particularly important given that the effectiveness of Nisin A in food can be influenced by a wide range of factors including fat content (Jung et al., 1992; Davies et al., 1999), proteolytic degradation (Murray and Richard, 1997), partitioning into polar or nonpolar food components (Murray and Richard, 1997) and sodium chloride concentrations (Chollet et al., 2008). Thus, to evaluate the efficacy of Nisin V in a situation where Nisin A is traditionally used, the efficacy of Nisin A, Nisin V and Nisin T was compared using frankfurters, a food frequently associated with L. monocytogenes contamination, spiked with a strain L. monocytogenes F2365 associated with an epidemic outbreak of listeriosis (Linnan et al., 1988; Mascola et al., 1988). Previously, L. monocytogenes F2365 was tagged with a luciferase‐based reporter system that allows for real‐time monitoring in food as well as in vivo locations (Riedel et al., 2007). The resultant strain was named F2365lux. For food assays, a commercially available frankfurter was homogenized and placed into sterile containers to which L. monocytogenes F2365lux was added to a concentration of 1 × 107 cfu l−1. Each homogenate of 0.2 ml was transferred to multiwell plates and bioluminescence was quantified using a Xenogen IVIS 100 imager (Time T0). Purified Nisin A, Nisin V or Nisin T peptide was then added to reach a final concentration of 7.5 mg l−1. Following incubation at 37°C for 1 h, bacterial growth was monitored by both bioluminescence imaging (RLU) and plate counts. In the presence of either Nisin A or Nisin T L. monocytogenes F2365lux numbers increased as indicated by increased bioluminescence from 2.54+E05 relative light units (RLU) and 2.64+E05 RLU to 3.16+E05 RLU and 3.64+E05 RLU, respectively) after 1 h (Fig. 3) whereas in the corresponding Nisin V‐treated samples, there was a marked decrease in bioluminescence from 2.53+E05 RLU to 1.71+E05 (Fig. 3). CFU counts after 1 h established that this difference in bioluminescence corresponded to the presence of almost 1 log fewer F2365lux cells in the Nisin V‐treated frankfurter (9.45 ± 2.7%) relative to the numbers present in the Nisin A‐ and Nisin T‐treated samples [100% and 89.16 ± 20.8% respectively (Fig. 3)]. While these results are in close agreement with the broth‐based kill curve experiments described above, they are important in their own right in that they demonstrate that the enhanced potency of Nisin V is maintained even within a complex and high‐fat food matrix (total fat content 31.5%). This is reassuring given the problems associated with the inactivity of Nisin in certain foods.


Studies with bioengineered Nisin peptides highlight the broad-spectrum potency of Nisin V.

Field D, Quigley L, O'Connor PM, Rea MC, Daly K, Cotter PD, Hill C, Ross RP - Microb Biotechnol (2010)

IVIS imaging of the kill effect of Nisin peptides (7.5 mg l−1) against L. monocytogenes F2365lux in frankfurter meat over a 1 h exposure period. The top row depicits the image at time 0 (T0). The bottom row depicts the survival of L. monocytogenes F2365lux after 1 h (T1). The data points represent the corresponding RLU values for images. Rel % Surv figures refer to percentage survival of F2365lux as determined by CFU counts after 1 h (T1) where WT Nisin A = 100%.
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Related In: Results  -  Collection

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f3: IVIS imaging of the kill effect of Nisin peptides (7.5 mg l−1) against L. monocytogenes F2365lux in frankfurter meat over a 1 h exposure period. The top row depicits the image at time 0 (T0). The bottom row depicts the survival of L. monocytogenes F2365lux after 1 h (T1). The data points represent the corresponding RLU values for images. Rel % Surv figures refer to percentage survival of F2365lux as determined by CFU counts after 1 h (T1) where WT Nisin A = 100%.
Mentions: Having established the potency of Nisin V against L. monocytogenes using a variety of laboratory‐based assays, we sought to determine whether this enhanced effectiveness could be translated to a food matrix. This was particularly important given that the effectiveness of Nisin A in food can be influenced by a wide range of factors including fat content (Jung et al., 1992; Davies et al., 1999), proteolytic degradation (Murray and Richard, 1997), partitioning into polar or nonpolar food components (Murray and Richard, 1997) and sodium chloride concentrations (Chollet et al., 2008). Thus, to evaluate the efficacy of Nisin V in a situation where Nisin A is traditionally used, the efficacy of Nisin A, Nisin V and Nisin T was compared using frankfurters, a food frequently associated with L. monocytogenes contamination, spiked with a strain L. monocytogenes F2365 associated with an epidemic outbreak of listeriosis (Linnan et al., 1988; Mascola et al., 1988). Previously, L. monocytogenes F2365 was tagged with a luciferase‐based reporter system that allows for real‐time monitoring in food as well as in vivo locations (Riedel et al., 2007). The resultant strain was named F2365lux. For food assays, a commercially available frankfurter was homogenized and placed into sterile containers to which L. monocytogenes F2365lux was added to a concentration of 1 × 107 cfu l−1. Each homogenate of 0.2 ml was transferred to multiwell plates and bioluminescence was quantified using a Xenogen IVIS 100 imager (Time T0). Purified Nisin A, Nisin V or Nisin T peptide was then added to reach a final concentration of 7.5 mg l−1. Following incubation at 37°C for 1 h, bacterial growth was monitored by both bioluminescence imaging (RLU) and plate counts. In the presence of either Nisin A or Nisin T L. monocytogenes F2365lux numbers increased as indicated by increased bioluminescence from 2.54+E05 relative light units (RLU) and 2.64+E05 RLU to 3.16+E05 RLU and 3.64+E05 RLU, respectively) after 1 h (Fig. 3) whereas in the corresponding Nisin V‐treated samples, there was a marked decrease in bioluminescence from 2.53+E05 RLU to 1.71+E05 (Fig. 3). CFU counts after 1 h established that this difference in bioluminescence corresponded to the presence of almost 1 log fewer F2365lux cells in the Nisin V‐treated frankfurter (9.45 ± 2.7%) relative to the numbers present in the Nisin A‐ and Nisin T‐treated samples [100% and 89.16 ± 20.8% respectively (Fig. 3)]. While these results are in close agreement with the broth‐based kill curve experiments described above, they are important in their own right in that they demonstrate that the enhanced potency of Nisin V is maintained even within a complex and high‐fat food matrix (total fat content 31.5%). This is reassuring given the problems associated with the inactivity of Nisin in certain foods.

Bottom Line: In contrast, Nisin V displayed increased potency against all targets tested including hVISA strains and the hyper-virulent Clostridium difficile ribotype 027 and against important food pathogens such as Listeria monocytogenes and Bacillus cereus.Significantly, this enhanced activity was validated in a model food system against L. monocytogenes.We conclude that Nisin V possesses significant potential as a novel preservative or chemotherapeutic compound.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology, University College Cork, Cork, Ireland.

Show MeSH
Related in: MedlinePlus