Department of Biology, University of Alabama a t Birmingham, Birmingham, AL 35294-1 170, USA Aeromonas hydrophila, a gastrointestinal pathogen of humans, was shown to exhibit a significant adaptive acid tolerance response (ATR) capable of protecting cells from severe acid at a pH of 3.5. The ATR was induced by exposure to a relatively mild pH level of 5-0 for 20 min. Adaptation required protein...

The survival of Campylobacter jejuni and Campylobacter coli at pH 7.0, 6.0, 5.0 and 4.0 for up to 24 h, and the induction of an acid adaptation response in 12 C. jejuni and 10 C. coli strains in early exponential or late stationary phases in tryptic soy broth (TSB) and Brucella broth were investigated. C. coli strains were more sensitive than C. jejuni in media adjusted to pH 5.0 or 4.0 with hy...

Formate dehydrogenase (FDH) is involved in various higher plant abiotic stress responses. Here, we investigated the role of rice bean (Vigna umbellata) VuFDH in Al and low pH (H(+)) tolerance. Screening of various potential substrates for the VuFDH protein demonstrated that it functions as a formate dehydrogenase. Quantitative reverse transcription-PCR and histochemical analysis showed that the...

In this study we evaluated the effect of chitosan nanoparticles on the acid tolerance response (ATR) of adhered Streptococcus mutans. An ATR was induced by exposing S. mutans to pH 5.5 for 2 h and confirmed by exposing the acid-adapted cells to pH 3.5 for 30 min, with the majority of cells appearing viable according to the LIVE/DEAD® technique. However, when chitosan nanoparticles were present ...

A positive correlation has been demonstrated between the ability of Rhizobium strains to colonize acidic agar surfaces and their production of extracellular polysaccharide (EPS) in solution culture at pH 7.0. This set of experiments examined the effects of EPS on solution pH levels and Al activity, two common growth-limiting factors in acid soils. Samples of EPS from each of 20 previously acids...

BACKGROUND The proton-activated G protein-coupled receptor GPR4 is expressed in many tissues including white adipose tissue. GPR4 is activated by extracellular protons in the physiological pH range (i.e. pH 7.7 - 6.8) and is coupled to the production of cAMP. METHODS We examined mice lacking GPR4 and examined glucose tolerance and insulin sensitivity in young and aged mice as well as in mice ...

An agar plate method has been developed for the rapid, preliminary screening of large numbers of rhizobia for tolerance to acidity and aluminum (acid-Al). Media containing pH indicators are used, and distinguish true tolerance from cases where growth depends on a previous pH shift. Strains which were highly tolerant or sensitive to acid Al on agar behaved similarly in defined liquid media. Stra...