کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
4370093 | 1616766 | 2006 | 7 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Listeria innocua and Lactobacillus delbrueckii subsp. bulgaricus employ different strategies to cope with acid stress
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کلمات کلیدی
موضوعات مرتبط
علوم زیستی و بیوفناوری
علوم کشاورزی و بیولوژیک
دانش تغذیه
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
Responses of Listeria innocua and Lactobacillus delbrueckii subsp. bulgaricus to a rapid change in extracellular pH (pHex) from pHex 6 to a range of concentrations down to pHex 3.0 were examined, using HCl and lactic acid (LA) as acidulants. A new fluorescent probe 5-(and-6)-carboxy-2â², 7â²-dichlorofluorescein diacetate succinimidyl ester (CDCFDA-SE) was employed that enabled reliable measurements of intracellular pH (pHi) to a minimum pHi of 4.0. Changes in pHi and H+ fluxes from immobilised bacteria were measured using fluorescence ratio imaging microscopy (FRIM) and a non-invasive ion flux measuring technique (MIFE), respectively. L. innocua maintained a relatively constant pHi of 5.5-6.1 at pHex 4 and 5 via H+ extrusion. In contrast, L. delbrueckii subsp. bulgaricus progressively lowered pHi towards pHex over the entire pHex range examined. The type of acidulant used influenced pH regulation with both pHi and H+-fluxes being more severely affected by LA compared to HCl. Overall, our data demonstrated different adaptive strategies in these two bacteria. While L. innocua expels protons to maintain a constant pHi, L. delbrueckii subsp. bulgaricus allows proton entry after acidic treatment so that pHi follows pHex.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: International Journal of Food Microbiology - Volume 110, Issue 1, 1 July 2006, Pages 1-7
Journal: International Journal of Food Microbiology - Volume 110, Issue 1, 1 July 2006, Pages 1-7
نویسندگان
Lana Shabala, Tom McMeekin, Birgitte Bjørn Budde, Henrik Siegumfeldt,