Characterization of Low Salinity Stress in Vibrio parahaemolyticus

2012 ◽  
Vol 75 (2) ◽  
pp. 231-237 ◽  
Author(s):  
WEI SHEN HUANG ◽  
HIN-CHUNG WONG
Keyword(s):  
Acetic Acid ◽  
Lactic Acid ◽  
Stationary Phase ◽  
Salinity Stress ◽  
Vibrio Parahaemolyticus ◽  
Acid Stress ◽  
Low Ph ◽  
Exponential Phase ◽  
Low Salinity ◽  
Acetic Acid Treatment

Vibrio parahaemolyticus is a marine foodborne pathogenic bacterium commonly found in seawater or seafood. This bacterium often encounters low salinity stress when the contaminated seafood is washed with fresh water during food processing. This study was conducted to investigate the response of exponential- and stationary-phase cells of V. parahaemolyticus ST550 to lethal or sublethal low salinity. Tolerance to lethal low salinity (0.25% NaCl) was enhanced in V. parahaemolyticus cells in the exponential phase by previous adaptation in sublethal low salinity (0.6% NaCl). Low salinity–adapted cells in the exponential phase were also cross-protected against the challenge of lethal low pH, indifferent to heat, and sensitized to bile, acetic acid, and lactic acid stress. The adapted cells in the stationary phase were significantly protected against heat treatment at 44°C for 10 and 15 min, sensitized to bile and acetic acid treatment, and indifferent to low pH and lactic acid.

Microarray-based transcriptome ofListeria monocytogenesadapted to sublethal concentrations of acetic acid, lactic acid, and hydrochloric acid

2012 ◽  
Vol 58 (9) ◽  
pp. 1112-1123 ◽  
Author(s):  
Girum Tadesse Tessema ◽  
Trond Møretrø ◽  
Lars Snipen ◽  
Even Heir ◽  
Askild Holck ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Lactic Acid ◽  
Hydrochloric Acid ◽  
Organic Acids ◽  
Compatible Solutes ◽  
Foodborne Pathogen ◽  
Acid Stress ◽  
Low Ph ◽  
Transcriptional Responses ◽  
Ph Stress

Listeria monocytogenes , an important foodborne pathogen, commonly encounters organic acids in food-related environments. The transcriptome of L. monocytogenes L502 was analyzed after adaptation to pH 5 in the presence of acetic acid, lactic acid, or hydrochloric acid (HCl) at 25 °C, representing a condition encountered in mildly acidic ready-to-eat food kept at room temperature. The acid-treated cells were compared with a reference culture with a pH of 6.7 at the time of RNA harvesting. The number of genes and magnitude of transcriptional responses were higher for the organic acids than for HCl. Protein coding genes described for low pH stress, energy transport and metabolism, virulence determinates, and acid tolerance response were commonly regulated in the 3 acid-stressed cultures. Interestingly, the transcriptional levels of histidine and cell wall biosynthetic operons were upregulated, indicating possible universal response against low pH stress in L. monocytogenes. The opuCABCD operon, coding proteins for compatible solutes transport, and the transcriptional regulator sigL were significantly induced in the organic acids, strongly suggesting key roles during organic acid stress. The present study revealed the complex transcriptional responses of L. monocytogenes towards food-related acidulants and opens the roadmap for more specific and in-depth future studies.

Glucolytic fingerprinting reveals metabolic groups within the genus Bifidobacterium: an exploratory study

2016 ◽  
Vol 7 (2) ◽  
pp. 265-273 ◽  
Author(s):  
D. Rios-Covián ◽  
B. Sánchez ◽  
I. Cuesta ◽  
S. Cueto-Díaz ◽  
A.M. Hernández-Barranco ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Lactic Acid ◽  
Discriminant Analysis ◽  
Stationary Phase ◽  
Organic Acid ◽  
Exponential Phase ◽  
Resting Cells ◽  
Bifidobacterium Adolescentis ◽  
Organic Acid Production ◽  
Acid Ratio

Microorganisms of the genus Bifidobacterium are inhabitants of diverse niches including the digestive tract of humans and animals. The species Bifidobacterium adolescentis, Bifidobacterium animalis, Bifidobacterium bifidum, Bifidobacterium breve and Bifidobacterium longum have qualified presumption of safety status granted by EFSA and several strains are considered probiotic, and are being included in functional dairy fermented products. In the present work we carried out a preliminary exploration of general metabolic characteristics and organic acid production profiles of a reduced number of strains selected from these and other species of the genus Bifidobacterium. The use of resting cells allowed obtaining metabolic fingerprints without interference of metabolites accumulated during growth in culture media. Acetic acid was the most abundant organic acid formed per mol of glucose consumed (from 1.07±0.03 to 1.71±0.22 mol) followed by lactic acid (from 0.34±0.06 to 0.90±0.12 mol), with moderate differences in production among strains; pyruvic, succinic and formic acids were also produced at considerably lower proportions, with variability among strains. The acetic to lactic acid ratio showed lower values in stationary phase as regard to the exponential phase for most, but not all, the microorganisms; this was due to a decrease in acetic acid molar proportions together with increases of lactic acid proportions in stationary phase. A linear discriminant analysis allowed to cluster strains into species with 51-100% probability, evidencing different metabolic profiles, according to the relative production of organic acids from glucose by resting cells, of microorganisms collected at the exponential phase of growth. Looking for a single metabolic marker that could adequately discriminate metabolic groups, we found that groups established by the acetic to lactic acid ratio fit well with differences previously evidenced by the discriminant analysis. The proper establishment of metabolic groups within the genus Bifidobacterium could help to select the best suited probiotic strains for specific applications.

Susceptibility of the Heat-, Acid-, and Bile-Adapted Vibrio vulnificus to Lethal Low-Salinity Stress

2006 ◽  
Vol 69 (12) ◽  
pp. 2924-2928 ◽  
Author(s):  
HIN-CHUNG WONG ◽  
SHU-HUI LIU
Keyword(s):  
Stationary Phase ◽  
Salinity Stress ◽  
Natural Environment ◽  
Food Processing ◽  
Vibrio Vulnificus ◽  
Pathogenic Bacterium ◽  
Protective Response ◽  
Low Salinity ◽  
Salinity Challenge ◽  
Insight Into

As a marine pathogenic bacterium that inhabits seawater or seafood, Vibrio vulnificus encounters low salinity and other stresses in the natural environment and during food processing. This investigation explores the cross-protective response of sublethal heat-, acid-, or bile-adapted V. vulnificus YJ03 against lethal low-salinity stress. Experimental results reveal that the acid (pH 4.4)– and heat (41°C)–adapted V. vulnificus were not cross-protected against the lethal low-salinity challenge (0.04% NaCl). The bile (0.05%)–adapted exponential- and stationary-phase cells were cross-protected against low salinity, whereas low-salinity (0.12% NaCl)–adapted stationary cells were sensitized against 12% bile stress. Results of this study provide further insight into the interaction between low salinity and other common stresses in V. vulnificus.

Characterization of the Low-Salinity Stress in Vibrio vulnificus

2008 ◽  
Vol 71 (2) ◽  
pp. 416-419 ◽  
Author(s):  
HIN-CHUNG WONG ◽  
SHU-HUI LIU
Keyword(s):  
Salinity Stress ◽  
Food Processing ◽  
Vibrio Vulnificus ◽  
Exponential Phase ◽  
Salinity Adaptation ◽  
Significant Protection ◽  
Low Salinity ◽  
Short Period ◽  
Nonculturable State

Vibrio vulnificus is a marine pathogenic bacterium commonly found in seawater or seafood. This organism encounters low-salinity stress in its natural environment and during food processing. This study was designed to investigate the response of V. vulnificus YJ03 to lethal low salinity (0.04% NaCl) and its adaptation to sublethal salinity (0.12% NaCl with 20 amino acids added). A short period in the nonculturable state was induced by lethal low-salinity stress followed by cell death after 30 min of stress. Addition of 1 mM glycine betaine or 0.5 mM sucrose reduced the damage. Low-salinity adaptation was achieved in the exponential-phase cells but not in the stationary-phase cells. Significant protection against lethal low-salinity stress was attained when the cells were adapted for as little as 1.5 min. The adapted cells were significantly protected against lethal low salinity and 2.4% sodium sorbate but sensitized to the challenge of heat (52°C) and acid (pH 3.2). Nonlethal lowsalinity treatment of seafood should be avoided to prevent stress adaptation of V. vulnificus.

scholarly journals Impact of Short-term Artificial Low Salinity Stress on the Flavor Quality of Scylla Paramamosain

2021 ◽  
Vol 36 (2) ◽  
pp. 179-195
Author(s):  
Tu Chunfei ◽  
Li Xing ◽  
Wang Huan ◽  
Chen Yuhao ◽  
Liang Guoling ◽  
...  
Keyword(s):  
Amino Acids ◽  
Lactic Acid ◽  
Amino Acid ◽  
Salinity Stress ◽  
Free Amino ◽  
Scylla Paramamosain ◽  
Low Salinity ◽  
Salinity Control ◽  
Cumulative Amount

Scylla paramamosain is a kind of large euryhaline marine crab. As an important physicochemical parameter of seawater, salinity has a great impact on the survival, growth and quality of Scylla paramamosain. This research tested the content of non-volatile flavor substance, lactic acid and taurine on the 0, 1st, 3rd, 7th and 15th day in three salinity gradients (3, 13, 23) with HPLC (High-performance Liquid Chromatography) technology. Results have shown that in low salinity stress, the cumulative amount of free amino acids in muscle of Scylla paramamosain is more than that in hepatopancreas, while the cumulative amount of essential amino acids in hepatopancreas is more than that in muscle. In muscle, contents of three flavor amino acids are ranked as follows: sweet, bitter and delicious amino acid, and in hepatopancreas, it is bitter, sweet and delicious amino acid. The fluctuation rule of free amino acid, essential amino acid and lactic acid in Scylla paramamosain in the low salinity group is similar to that of other salinity control group, while the content of sweet amino acid, bitter amino acid, nucleotide, EUC, taurine is different from that of other salinity control groups.

Comparative Analysis of Acid Resistance between Susceptible and Multi-Antimicrobial-Resistant Salmonella Strains Cultured under Stationary-Phase Acid Tolerance–Inducing and Noninducing Conditions

2003 ◽  
Vol 66 (5) ◽  
pp. 732-740 ◽  
Author(s):  
R. T. BACON ◽  
J. N. SOFOS ◽  
P. A. KENDALL ◽  
K. E. BELK ◽  
G. C. SMITH
Keyword(s):  
Stationary Phase ◽  
Antimicrobial Agents ◽  
Acid Stress ◽  
Acid Tolerance ◽  
Acid Resistance ◽  
Low Ph ◽  
Acid Exposure ◽  
Acid Adaptation ◽  
Acid Shock ◽  
Resistant Strains

This study compared acid resistance levels among five antimicrobial-susceptible strains of Salmonella and five strains that were simultaneously resistant to a minimum of six antimicrobial agents. The induction of a stationary-phase acid tolerance response (ATR) was attempted by both transient low-pH acid shock and acid adaptation. For acid shock induction, strains were grown for 18 h in minimal E medium containing 0.4% glucose (EG medium) and exposed to sublethal acid stress (pH 4.3) for 2 h, and subsequently, both shocked and nonshocked cultures were acid challenged (pH 3.0) for 4 h. Acid adaptation was achieved by growing strains for 18 h in tryptic soy broth containing 1.0% glucose (TSB+G), while nonadapted cultures were grown for 18 h in glucose-free tryptic soy broth (TSB−G). Acid-adapted and nonadapted inocula were acid challenged (pH 2.3) for 4 h. Initial (0 h) mean populations of nonchallenged Salmonella were 8.5 to 8.7, 8.4 to 8.8, and 8.2 to 8.3 log CFU/ml for strains grown in EG medium, TSB−G, and TSB+G, respectively. After 4 h of acid challenge, mean populations were 3.0 to 4.8 and 2.5 to 3.7 log CFU/ml for previously acid-shocked susceptible and resistant strains, respectively, while corresponding counts for nonshocked strains were 4.3 to 5.5 log CFU/ml and 3.9 to 4.9 log CFU/ml. Following 4 h of acid exposure, acid-adapted cultures of susceptible and resistant strains had mean populations of 6.1 to 6.4 log CFU/ml and 6.4 to 6.6 log CFU/ml, respectively, while corresponding counts for nonadapted cultures were 1.9 to 2.1 log CFU/ml and 1.8 to 2.0 log CFU/ml, respectively. A low-pH–inducible ATR was not achieved through transient acid shock, while an ATR was evident following acid adaptation, as adapted populations were 4.2 to 4.8 log units larger than nonadapted populations following acid exposure. Although some strain-dependent variations in acid resistance were observed, results from this study suggest no association between susceptibility to antimicrobial agents and the ability of the Salmonella strains evaluated to survive low-pH stress.

729. Characteristics of a presumptive pediococcus occurring in New Zealand Cheddar cheese

1958 ◽  
Vol 25 (3) ◽  
pp. 409-413 ◽  
Author(s):  
J. C. Dacre
Keyword(s):  
Acetic Acid ◽  
Lactic Acid ◽  
New Zealand ◽  
Type Species ◽  
Cheddar Cheese ◽  
Low Ph ◽  
Acid Media ◽  
High Concentrations ◽  
Acid Producing Bacteria ◽  
Gram Positive Cocci

1. Cultural and biochemical details are given of a homofermentative species of lactic acid-producing bacteria, repeatedly isolated from typical maturing New Zealand Cheddar cheese.2. The Gram-positive cocci, occurring mainly in pairs and tetrads in acid media, are greatly stimulated in growth by the presence of yeast or tomato extracts. The organism converts glucose into inactive lactic acid and smaller amounts of acetic acid.3. With the exceptions that the organism does not ferment trehalose and is less tolerant to low pH and high concentrations of Teepol, all its characteristics are similar to those for the genusPediococcus, in particular to the type speciesP. cerevisiaeBalcke.

Augmentation of Killing of Escherichia coli O157 by Combinations of Lactate, Ethanol, and Low-pH Conditions

1999 ◽  
Vol 65 (3) ◽  
pp. 1308-1311 ◽  
Author(s):  
Sarah L. Jordan ◽  
Jayne Glover ◽  
Laura Malcolm ◽  
Fiona M. Thomson-Carter ◽  
Ian R. Booth ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Stationary Phase ◽  
Acid Tolerance ◽  
Low Ph ◽  
Exponential Phase ◽  
Escherichia Coli O157 ◽  
Cytoplasmic Ph ◽  
Ph Homeostasis ◽  
Acid Tolerant ◽  
Ph Conditions

ABSTRACT The acid tolerance of Escherichia coli O157:H7 strains can be overcome by addition of lactate, ethanol, or a combination of the two agents. Killing can be increased by as much as 4 log units in the first 5 min of incubation at pH 3 even for the most acid-tolerant isolates. Exponential-phase, habituated, and stationary-phase cells are all sensitive to incubation with lactate and ethanol. Killing correlates with disruption of the capacity for pH homeostasis. Habituated and stationary-phase cells can partially offset the effects of the lowering of cytoplasmic pH.

scholarly journals Effects of Acid Stress on Vibrio parahaemolyticus Survival and Cytotoxicity

2004 ◽  
Vol 67 (7) ◽  
pp. 1328-1334 ◽  
Author(s):  
P. S. MARIE YEUNG ◽  
KATHRYN J. BOOR
Keyword(s):  
Stationary Phase ◽  
Vibrio Parahaemolyticus ◽  
Acid Stress ◽  
Acid Tolerance ◽  
Acid Exposure ◽  
Bacterial Survival ◽  
Acid Tolerance Response ◽  
Tolerance Response ◽  
Acidic Conditions ◽  
Acid Challenge

For several foodborne bacterial pathogens, an acid tolerance response appears to be an important strategy for counteracting acid stress imposed either during food processing or by the human host. The acid tolerance response enhances bacterial survival of lethal acid challenge following prior exposure to sublethal acidic conditions. Previous studies have revealed relationships between a foodborne pathogen's ability to survive acid challenge and its infectious dose. Vibrio parahaemolyticus is capable of causing gastroenteritis when sufficient cells of pathogenic strains are consumed. This study was designed to characterize acid sensitivities and to compare the effects of sublethal acid exposure (adaptation) on survival capabilities and cytotoxicities of different V. parahaemolyticus strains. Survival of acid challenge by stationary-phase cells differed by up to 3 log CFU/ml among the 25 isolates tested. No differences in acid resistance were found between strains when they were grouped by source (clinical isolates versus those obtained from food). Survival at pH 3.6 for log-phase cells that had been previously exposed to sublethal acidic conditions (pH 5.5) was enhanced compared with that for cells not previously exposed to pH 5.5. However, for stationary-phase cells, exposure to pH 5.5 impaired both subsequent survival at pH 3.6 and cytotoxicity to human epithelial cells. Relative cytotoxicities of nonadapted stationary-phase cells were 1.2- to 4.8-fold higher than those of adapted cells. Sublethal acid exposure appears to impose measurable growth phase–dependent effects on subsequent lethal acid challenge survival and cytotoxicity of V. parahaemolyticus.

scholarly journals Transcriptomic Analysis of Pediococcus pentosaceus Reveals Carbohydrate Metabolic Dynamics Under Lactic Acid Stress

2021 ◽  
Vol 12 ◽  
Author(s):  
Dong Han ◽  
Qiaojuan Yan ◽  
Jun Liu ◽  
Zhengqiang Jiang ◽  
Shaoqing Yang
Keyword(s):  
Acetic Acid ◽  
Lactic Acid ◽  
Carbohydrate Metabolism ◽  
Stress Responses ◽  
Protective Efficacy ◽  
Acid Stress ◽  
Cell Factory ◽  
Transcriptional Responses ◽  
Pediococcus Pentosaceus ◽  
Ecological Fitness

Stress physiology of lactic acid bacteria (LAB) is crucial to their ecological fitness and applicational implications. As a self-imposed stress, lactic acid is the major final metabolic product of LAB and its accumulation can be detrimental to bacterial cells. However, the relationship between LAB carbohydrate metabolism, the primary energy supplying bioactivities, and lactic acid stress responses is not fully understood. Pediococcus pentosaceus has been recognized as an important cell factory and demonstrated probiotic activities. This study investigated behavior of P. pentosaceus under lactic and acetic acid stresses, particularly with supplementations of metabolizable carbohydrates. Lactic and acetic acid retain similar growth stagnation effect, and both resulted in cell death in P. pentosaceus. All metabolizable carbohydrates improved bacterial survival compared to lactic acid control, while xylooligosaccharides (XOS) exerted the highest viability protective efficacy, 0.82 log CFU/mL higher population survived than other carbohydrates after 30 h of incubation. RNA-seq pipeline showcased the intensive global transcriptional responses of P. pentosaceus to lactic acid, which caused significant regulations (more than 2 Log2 fold) of 16.5% of total mRNA coding genes. Glucose mainly led to gene suppressions (83 genes) while XOS led to gene up-regulations (19 genes) under lactic acid stress. RT-qPCR study found that RNA polymerase-centered transcriptional regulation is the primary regulatory approach in evaluated culture conditions. The synergy between lactic acid stress and carbohydrate metabolism should be attentively contemplated in future studies and applications.

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