Production of phenylalanine and organic acids by phosphoenolpyruvate carboxylase-deficient mutants ofEscherichia coli

1987 ◽  
Vol 2 (3) ◽  
pp. 143-149 ◽  
Author(s):  
Judith E. Miller ◽  
Keith C. Backman ◽  
Mary Jane O'Connor ◽  
Randolph T. Hatch
Keyword(s):  
Organic Acids ◽  
Phosphoenolpyruvate Carboxylase ◽  
Ofescherichia Coli

Independent Effects of Acetic Acid and pH on Survival ofEscherichia coli in Simulated Acidified Pickle Products†‡

2004 ◽  
Vol 67 (1) ◽  
pp. 12-18 ◽  
Author(s):  
F. BREIDT ◽  
J. S. HAYES ◽  
R. F. McFEETERS
Keyword(s):  
Acetic Acid ◽  
Organic Acids ◽  
Acid Resistance ◽  
Ofescherichia Coli ◽  
Acid Solutions ◽  
Specific Effects ◽  
Effects Of Ph ◽  
Ph Range ◽  
Independent Effects ◽  
D Values

Our objective was to determine the effects of organic acids and pH on the rate at which selected strains ofEscherichia coli O157:H7 die in acid solutions representative of acidified pickle products (pH < 4.6). We used gluconic acid/sodium gluconate (pKa = 3.7) as a noninhibitory buffer to maintain pH at selected values in the absence of other organic acids. This was possible because we found that the inhibitory effects of this acid onE. coli strains at pH 3.1 were independent of acid concentration over a range of 2 to 200 mM. By this method, the lethal effects of acetic acid solutions (100 to 400 mM) at selected pH values between 3.1 and 4.1 were compared with the effects of pH alone (as determined using gluconate buffer). We found D-values were two- to fourfold lower with acetic acid compared with the effect of pH alone for simulated pickle brines in this pH range. Glutamic acid, an amino acid that is known to enhance acid resistance inE. coli and is a component of pickle brines, protected theE. coli strains from the specific effects of acetic acid.

scholarly journals Comparative transcriptome analysis reveals key genes potentially related to organic acid and sugar accumulation in loquat

PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0238873
Author(s):  
Jun Yang ◽  
Jing Zhang ◽  
Xian-Qian Niu ◽  
Xue-Lian Zheng ◽  
Xu Chen ◽  
...  
Keyword(s):  
Organic Acids ◽  
Organic Acid ◽  
Fruit Development ◽  
Phosphoenolpyruvate Carboxylase ◽  
Sucrose Synthase ◽  
Sugar Content ◽  
Sucrose Phosphate Synthase ◽  
Sucrose Phosphate ◽  
Sucrose Cleavage ◽  
Phosphate Synthase

Organic acids and sugars are the primary components that determine the quality and flavor of loquat fruits. In the present study, major organic acids, sugar content, enzyme activities, and the expression of related genes were analyzed during fruit development in two loquat cultivars, ’JieFangZhong’ (JFZ) and ’BaiLi’ (BL). Our results showed that the sugar content increased during fruit development in the two cultivars; however, the organic acid content dramatically decreased in the later stages of fruit development. The differences in organic acid and sugar content between the two cultivars primarily occured in the late stage of fruit development and the related enzymes showed dynamic changes in activies during development. Phosphoenolpyruvate carboxylase (PEPC) and mNAD malic dehydrogenase (mNAD-MDH) showed higher activities in JFZ at 95 days after flowering (DAF) than in BL. However, NADP-dependent malic enzyme (NADP-ME) activity was the lowest at 95 DAF in both JFZ and BL with BL showing higher activity compared with JFZ. At 125 DAF, the activity of fructokinase (FRK) was significantly higher in JFZ than in BL. The activity of sucrose synthase (SUSY) in the sucrose cleavage direction (SS-C) was low at early stages of fruit development and increased at 125 DAF. SS-C activity was higher in JFZ than in BL. vAI and sucrose phosphate synthase (SPS) activities were similar in the two both cultivars and increased with fruit development. RNA-sequencing was performed to determine the candidate genes for organic acid and sugar metabolism. Our results showed that the differentially expressed genes (DEGs) with the greated fold changes in the later stages of fruit development between the two cultivars were phosphoenolpyruvate carboxylase 2 (PEPC2), mNAD-malate dehydrogenase (mNAD-MDH), cytosolic NADP-ME (cyNADP-ME2), aluminum-activated malate transporter (ALMT9), subunit A of vacuolar H+-ATPase (VHA-A), vacuolar H+-PPase (VHP1), NAD-sorbitol dehydrogenase (NAD-SDH), fructokinase (FK), sucrose synthase in sucrose cleavage (SS-C), sucrose-phosphate synthase 1 (SPS1), neutral invertase (NI), and vacuolar acid invertase (vAI). The expression of 12 key DEGs was validated by quantitative reverese transcription PCR (RT-qPCR). Our findings will help understand the molecular mechanism of organic acid and sugar formation in loquat, which will aid in breeding high-quality loquat cultivars.

Regulation of soybean nodule phosphoenolpyruvate carboxylase in vivo

1996 ◽  
Vol 97 (3) ◽  
pp. 531-535 ◽  
Author(s):  
Carol Wadham ◽  
Heike Winter ◽  
Kathryn A. Schuller
Keyword(s):  
Phosphoenolpyruvate Carboxylase ◽  
Soybean Nodule

Novel Approach of Use of Organic Acids and Salts as a Potent Alternative to Antibiotics

2011 ◽  
Vol 3 (5) ◽  
pp. 45-47
Author(s):  
P. G. Umbarkar P. G. Umbarkar ◽  
◽  
Swati. N Zodpe
Keyword(s):  
Organic Acids ◽  
Novel Approach
Sign in / Sign up

Export Citation Format

Share Document