Extracellular protectants produced byClostridium perfringenscells at elevated temperatures

Abstract

Aim: The mechanisms of adaptation of Clostridium perfringens to high temperatures are not well understood. In this work, the involvement of extracellular compounds in protection to heat was determined. Methods and Results: Cells were grown in fluid thioglycollate medium or chicken broth. When mid‐log phase was reached, they were heat‐shocked at 50°C for 30 min. Then cultures were centrifuged and supernatants were transferred to nonshocked cells. Heat tolerance of these cells was performed at 55°C. Viable cells were determined. In some cases, supernatants were heated at 65°C or 100°C or treated with trypsin. Supernatants were fractionated and PAGE was made of fractions showing heat‐protective activity. When C. perfringens was exposed to a heat shock at 50°C, extracellular factors were found in the culture supernatant that provided protection to cells not exposed to a heat shock. The extracellular factors were sensitive to heat and trypsin treatment suggesting a protein component. SDS‐PAGE analysis of supernatant fractions from heat‐treated cells revealed two induced proteins (56 and 125 kDa) that could be involved in heat tolerance. Conclusion: In this work, the presence and thermoprotective activity of extracellular factors produced by C. perfringens under a heat shock was demonstrated. Significance and Impact of the Study: The detection of thermoprotective extracellular factors of C. perfringens will aid in our understanding of the physiology of survival of C. perfringens in foods.

Heat inactivation of Escherichia coli K12 MG1655: Effect of microbial metabolites and acids in spent medium

“…This observation suggests that the presence of specific proteins somehow alerts or protects the non pre-stressed cells leading to an increased thermotolerance. These findings are in agreement with the conclusion of Heredia et al (2009), who studied the involvement of extracellular compounds in the protection of Clostridium perfringens to heat, and showed that extracellular factors (proteins) produced by heat shocked cells have a thermoprotective function for non-stressed cells.…”

Clostridium perfringens: A Dynamic Foodborne Pathogen

“…The implications of these findings are extremely critical. Recently, it has been demonstrated that production of exometabolites of C. perfringens during heat challenge plays an important role in heat tolerance of this bacteria (Heredia et al 2008).…”

Spoilage by Alicyclobacillus Bacteria in Juice and Beverage Products: Chemical, Physical, and Combined Control Methods

“…The depleted content of divalent cations of endospores (such as in an adverse pH environment) would cause the decrease of their heat resistance, while the demineralized endospores would regain the heat resistance (Bender and Marquis ), but Yamazaki and others () found that the changes of heat resistance of A. acidoterrestris endospores were not significant when different divalent cations (including Ca 2+ ) were added into the medium, with better effects being observed when DPA and Ca 2+ were both added. Other factors influencing the heat resistance of vegetative cells include cell age, which is reflected in that the heat resistance is usually lower during the logarithmic phase than during the stationary phase, and cell populations, with large cell populations always to increase the heat resistance by excreting thermoprotective, extracellular proteins (Heredia and others ).…”