超高压导致芽孢亚致死损伤进而提高芽孢热敏感性
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摘要
分别使用150、350、550 MPa的压力在23℃下对枯草杆菌芽孢进行超高压处理,检测处理后芽孢样品的热敏感性、OD_(600)值和2,6-吡啶二羧酸(DPA)释放情况,并进行透射电镜观察。3个压力水平均能快速提高芽孢的热敏感性,150 MPa使得芽孢OD_(600)值降低、DPA显著释放、芽孢皮层明显水解、芽孢显著萌发。然而,使用350 MPa和550 MPa处理后,芽孢OD_(600)值变化和DPA释放不显著、芽孢皮层水解不明显、芽孢萌发不显著。研究结果表明:350 MPa和550 MPa处理导致了芽孢的亚致死损伤,而不是芽孢萌发,这种亚致死损伤增强了芽孢的热敏感性,并可能是高压热处理杀灭芽孢的原因之一。
Treated Bacillus subtilis spores with pressures of 150, 350 MPa and 550 MPa at 23 ℃, and the thermal sensitivity, OD_(600) value and DPA release of the spores were examined after ultrahigh pressure treatment, and the spores treated were also observed with TEM. The three pressure levels allenhanced quickly the thermal sensitivity of spores. 150 MPa caused the decrease of OD_(600) value, significant release of DPA, hydrolysis of spore cortex and significant spore germination. However, after treatment with 350 MPa and 550 MPa, there were no significant change of OD_(600) value, no significant DPA release, no hydrolysis of spore cortex and no significant germination of spores. The experimental results indicated that pressure treatment of 350 MPa and 550 MPa caused sub-lethal damage to spores instead of spore germination, and this sub-lethal damage enhanced spore thermal sensitivity, which is probably a reason for spore inactivation by high pressure thermal sterilization.
Treated Bacillus subtilis spores with pressures of 150, 350 MPa and 550 MPa at 23 ℃, and the thermal sensitivity, OD_(600) value and DPA release of the spores were examined after ultrahigh pressure treatment, and the spores treated were also observed with TEM. The three pressure levels allenhanced quickly the thermal sensitivity of spores. 150 MPa caused the decrease of OD_(600) value, significant release of DPA, hydrolysis of spore cortex and significant spore germination. However, after treatment with 350 MPa and 550 MPa, there were no significant change of OD_(600) value, no significant DPA release, no hydrolysis of spore cortex and no significant germination of spores. The experimental results indicated that pressure treatment of 350 MPa and 550 MPa caused sub-lethal damage to spores instead of spore germination, and this sub-lethal damage enhanced spore thermal sensitivity, which is probably a reason for spore inactivation by high pressure thermal sterilization.
引文
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[8]Wuytack E Y,Boven S,Michiels C W.Comparative study of pressure-induced germination of Bacillus subtilis spores at low and high pressures[J].Applied&Environmental Microbiology,1998,64(9):3220-3224
[9]Huo Z,Yang X,Raza W,et al.Investigation of factors influencing spore germination of Paenibacillus polymyxa,ACCC10252 and SQR-21[J].Applied Microbiology and Biotechnology,2010,87(2):527-536
[10]Minh H N T,Dantigny P,Perrier-Cornet J M,et al.Germination and inactivation of Bacillus subtilis,spores induced by moderate hydrostatic pressure[J].Biotechnology&Bioengineering,2010,107(5):876-883
[11]Daniel Baier,Kai Reineke,Isabel Doehner,et al.Fluorescence-based methods for the detection of pressure-induced spore germination and inactivation[J].High Pressure Research,2011,31(1):110-115
[12]Black E P,Linton M,Mccall R D,et al.The combined effects of high pressure and nisin on germination and inactivation of Bacillus spores in milk[J].Journal of Applied Microbiology,2008,105(1):78
[13]Ahn J,Balasubramaniam V M.Physiological responses of Bacillus amyloliquefaciens spores to high pressure[J].Journal of Microbiology&Biotechnology,2007,17(3):524-529
[14]Reineke K,Mathys A,Knorr D.The impact of high pressure and temperature on bacterial spores:inactivation mechanisms of Bacillus subtilis above 500 MPa[J].Journal of Food Science,2011,76(3):M189
[2]Black E P,Setlow P,Hocking A D,et al.Response of Spores to High-Pressure Processing[J].Comprehensive Reviews in Food Science&Food Safety,2007,6(4):103-119
[3]Gould G W,Sale A J.Initiation of germination of bacterial spores by hydrostatic pressure[J].Journal of General Microbiology,1970,60(3):335-346
[4]Wuytack E Y,Soons J,Poschet F,et al.Comparative Study of Pressure-and Nutrient-Induced Germination of Bacillus subtilis Spores[J].Applied&Environmental Microbiology,2000,66(1):257
[5]Madan Paidhungat,Barbara Setlow,William B Daniels,et al.Mechanisms of Induction of Germination of Bacillus subtilis Spores by High Pressure[J].Applied&Environmental Microbiology,2002,68(6):3172-3175
[6]Margosch D,Ehrmann M A,G?nzle M G,et al.Comparison of pressure and heat resistance of Clostridium botulinum and other endospores in mashed carrots[J].Journal of Food Protection,2004,67(11):2530-2537
[7]Black E P,Wei J,Atluri S,et al.Analysis of factors influencing the rate of germination of spores of Bacillus subtilis by very high pressure[J].Journal of Applied Microbiology,2007,102(1):65-76
[8]Wuytack E Y,Boven S,Michiels C W.Comparative study of pressure-induced germination of Bacillus subtilis spores at low and high pressures[J].Applied&Environmental Microbiology,1998,64(9):3220-3224
[9]Huo Z,Yang X,Raza W,et al.Investigation of factors influencing spore germination of Paenibacillus polymyxa,ACCC10252 and SQR-21[J].Applied Microbiology and Biotechnology,2010,87(2):527-536
[10]Minh H N T,Dantigny P,Perrier-Cornet J M,et al.Germination and inactivation of Bacillus subtilis,spores induced by moderate hydrostatic pressure[J].Biotechnology&Bioengineering,2010,107(5):876-883
[11]Daniel Baier,Kai Reineke,Isabel Doehner,et al.Fluorescence-based methods for the detection of pressure-induced spore germination and inactivation[J].High Pressure Research,2011,31(1):110-115
[12]Black E P,Linton M,Mccall R D,et al.The combined effects of high pressure and nisin on germination and inactivation of Bacillus spores in milk[J].Journal of Applied Microbiology,2008,105(1):78
[13]Ahn J,Balasubramaniam V M.Physiological responses of Bacillus amyloliquefaciens spores to high pressure[J].Journal of Microbiology&Biotechnology,2007,17(3):524-529
[14]Reineke K,Mathys A,Knorr D.The impact of high pressure and temperature on bacterial spores:inactivation mechanisms of Bacillus subtilis above 500 MPa[J].Journal of Food Science,2011,76(3):M189