scholarly journals Response of Lactobacillus plantarum VAL6 to challenges of pH and sodium chloride stresses

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Phu-Tho Nguyen ◽  
Thi-Tho Nguyen ◽  
Thi-Ngoc-Tuyen Vo ◽  
Thi-Thanh-Xuan Nguyen ◽  
Quoc-Khanh Hoang ◽  
...  
Keyword(s):  
Sodium Chloride ◽  
Mrna Expression ◽  
Lactobacillus Plantarum ◽  
Stress Condition ◽  
Chloride Concentration ◽  
Monosaccharide Composition ◽  
High Sodium ◽  
F Gene ◽  
Exopolysaccharide Biosynthesis ◽  
Galactose Content

AbstractTo investigate the effect of environmental stresses on the exopolysaccharide biosynthesis, after 24 h of culture at 37 °C with pH 6.8 and without sodium chloride, Lactobacillus plantarum VAL6 was exposed to different stress conditions, including pH (pHs of 3 and 8) and high sodium chloride concentration treatments. The results found that Lactobacillus plantarum VAL6 exposed to stress at pH 3 for 3 h gives the highest exopolysaccharide yield (50.44 g/L) which is 6.4 fold higher than non-stress. Under pH and sodium chloride stresses, the mannose content in exopolysaccharides decreased while the glucose increased in comparison with non-stress condition. The galactose content was highest under stress condition of pH 8 meantime rhamnose content increased sharply when Lactobacillus plantarum VAL6 was stressed at pH 3. The arabinose content in exopolysaccharides was not detected under non-stress condition but it was recorded in great amounts after 3 h of stress at pH 3. In addition, stress of pH 8 triggered the mRNA expression of epsF gene resulting in galactose-rich EPS synthesis. According to our results, the stresses of pH and sodium chloride enhance the production and change the mRNA expression of epsF gene, leading to differences in the monosaccharide composition of exopolysaccharides.

TURBIDITY OF SUSPENSIONS AND MORPHOLOGY OF RED HALOPHILIC BACTERIA AS INFLUENCED BY SODIUM CHLORIDE CONCENTRATION

1960 ◽  
Vol 6 (5) ◽  
pp. 535-543 ◽  
Author(s):  
Dinah Abram ◽  
N. E. Gibbons
Keyword(s):  
Sodium Chloride ◽  
Salt Concentration ◽  
Morphological Changes ◽  
Halophilic Bacteria ◽  
Chloride Concentration ◽  
Chloride Content ◽  
Wall Structure ◽  
Abrupt Decrease ◽  
High Sodium ◽  
Rigid Cell Wall

The optical densities of suspensions of cells of Halobacterium cutirubrum, H. halobium, or H. salinarium, grown in media containing 4.5 M sodium chloride, increase as the salt concentration of the suspending medium decreases, until a maximum is reached at about 2 M; below this concentration there is an abrupt decrease in optical density. The cells are rod shaped in 4.5 M salt and change, as the salt concentration decreases, through irregular transition forms to spheres; equal numbers of transition forms and spheres are present at the point of maximum turbidity, while spheres predominate at lower salt concentrations. Cells suspended in 3.0 M salt, although slightly swollen, are viable, but viability decreases rapidly with the more drastic changes in morphology at lower salt concentrations. Cells grown in the presence of iron are more resistant to morphological changes but follow the same sequence. Cells "fixed" with formaldehyde, at any point in the sequence, act as osmometers and do not rupture in distilled water although their volume increases 10–14 times. The results indicate that the red halophilic rods require a high sodium chloride content in their growth or suspending medium to maintain a rigid cell wall structure.

scholarly journals Effects of Sodium Chloride on Tyramine Production in a Fermented Food Model and its Inhibition by Tyrosine-degrading Lactobacillus plantarum JA-1199

2020 ◽  
Vol 74 (5) ◽  
pp. 391-397
Author(s):  
Janine Anderegg ◽  
Florentin Constancias ◽  
Leo Meile
Keyword(s):  
Lactic Acid ◽  
Sodium Chloride ◽  
Lactic Acid Bacteria ◽  
Lactobacillus Plantarum ◽  
Chloride Concentration ◽  
Fermented Food ◽  
Starter Cultures ◽  
Fermented Foods ◽  
Bacterial Strains ◽  
Safety Level

Tyramine is a health-adverse biogenic amine, which can accumulate in fermented foods like cheese by decarboxylation of the free amino acid tyrosine by either starter cultures or resident microbes such as lactic acid bacteria including Enterococcus spp., respectively. Our study aimed to show the effect of sodium chloride concentrations on tyramine production as well as to characterise bacterial strains as anti-tyramine biocontrol agents in a 2 mL micro-cheese fermentation model. The effect of sodium chloride on tyramine production was assayed with tyramine producing strains from eight different species or subspecies. Generally, an increase in sodium chloride concentration enhanced tyramine production, e.g. from 0% to 1.5% of sodium chloride resulted in an increase of tyramine of 870% with a Staphylococcus xylosus strain. In the biocontrol screening among lactic acid bacteria, a Lactobacillus plantarum JA-1199 strain was screened that could consume in successful competition with other resident bacteria tyrosine in the micro-cheese model as a source of energy gain. Thereby tyramine accumulation was reduced between 4% to 99%. The results of this study disclose a feasible strategy for decreasing tyramine concentration and increasing the safety level of fermented food. It is an example of development and application of bacterial isolates as starter or protective cultures in food, a biocontrol topic, which Oreste Ghisalba – in his project evaluation function of SNF and later on CTI – was promoting with great emphasis in our ETH Food Biotechnology research group.

Inhibition of Fatty Acid Synthetase in Halobacterium cutirubrum and Escherichia coli by High Salt Concentrations

1971 ◽  
Vol 49 (8) ◽  
pp. 953-958 ◽  
Author(s):  
E. L. Pugh ◽  
M. K. Wassef ◽  
M. Kates
Keyword(s):  
Fatty Acid ◽  
Sodium Chloride ◽  
Specific Activity ◽  
Fatty Acid Synthetase ◽  
Chloride Concentration ◽  
High Sodium ◽  
E Coli ◽  
Level Of Activity ◽  
Malonyl Coa ◽  
A Cell

A cell-free enzyme preparation from Halobacterium cutirubrum was shown to catalyze the biosynthesis of fatty acids from malonyl-CoA at zero sodium chloride concentration, with a specific activity about [Formula: see text] that of a similarly prepared fatty acid synthetase from E. coli. Both the H. cutirubrum synthetase and that from E. coli were strongly inhibited by high sodium chloride or potassium chloride concentrations (0.5–4 M). The malonyl-CoA: ACP transacylase, which catalyzes the first step in the fatty acid biosynthetic pathway, was shown to be strongly inhibited by salt in H. cutirubrum, but not in E. coli. It is concluded that H. cutirubrum contains a fatty acid synthetase system which normally operates at a very low level of activity as a result of inhibition by the high intracellular salt concentration present in this organism.

Sodium Chloride and Pathogenic Bacteria in a Vacuum-Packed Minced-Meat Product

1985 ◽  
Vol 48 (2) ◽  
pp. 150-155 ◽  
Author(s):  
H.-J. S. NIELSEN ◽  
P. ZEUTHEN
Keyword(s):  
Sodium Chloride ◽  
Salmonella Enteritidis ◽  
Pathogenic Bacteria ◽  
Storage Temperature ◽  
Meat Product ◽  
Chloride Concentration ◽  
Chloride Content ◽  
Inhibitory Effect ◽  
High Sodium ◽  
Salt Level

Development of Bacillus cereus, Salmonella enteritidis, Salmonella typhimurium and Yersinia enterocolitica in vacuum-packed Bologna-type sausage was highly influenced by sodium chloride level (brine concentrations 3.4, 4.5 and 6.0; 2.8 for salmonellae) with none of the bacteria growing at 6.0%. Growth of Staphylococcus aureus was unaffected even by the highest sodium chloride concentration used. Decreasing the storage temperature accentuated the inhibitory effect of sodium chloride on Y. enterocolitica and B. cereus. Initial numbers decreased slowly or remained static in sausage with a high sodium chloride content, when growth did not occur. At the low salt level, at 2–5°C, only Y. enterocolitica was not inhibited until the sodium chloride content was 4.5% and the storage temperature 2°C. At increased, but not unusual temperature, B. cereus could develop at 4.5% (12°C) and S. aureus at all salt levels (8–15°C).

Seed-germination ecology of glyphosate-resistant and glyphosate-susceptible biotypes of Echinochloa colona in Australia

2019 ◽  
Vol 70 (4) ◽  
pp. 367 ◽  
Author(s):  
Navneet Kaur Mutti ◽  
Gulshan Mahajan ◽  
Bhagirath Singh Chauhan
Keyword(s):  
Water Stress ◽  
Sodium Chloride ◽  
Seed Germination ◽  
Seedling Emergence ◽  
Chloride Concentration ◽  
Soil Surface ◽  
Burial Depth ◽  
Solution Ph ◽  
High Sodium ◽  
Wide Range

Echinochloa colona L. (Link) (awnless barnyard grass) is one of the top three most problematic weeds of summer crops in Australia. This weed has evolved resistance to glyphosate. A study was conducted to evaluate the effect of environmental factors on the germination and seedling emergence of a glyphosate-resistant (GR) and a glyphosate-susceptible (GS) biotype of E. colona. The two biotypes had similar germination and emergence responses to light and temperature conditions, water stress, solution pH, sorghum residue cover and seed burial depth. Light stimulated germination more than dark conditions, and seeds germinated at a wide range of alternating day/night temperatures, from 20°C/10°C to 35°C/25°C, whereas no seeds germinated at 15°C/5°C. These results suggest that E. colona can emerge in spring, summer and autumn in Queensland. The sodium chloride concentration required to inhibit 50% germination was greater for the GR biotype (209 mm) than the GS biotype (174 mm). Seed germination was not affected by pH in the range 4–10. Water stress reduced germination by 50% at an osmotic potential of –0.44 MPa. In a shade-house study, retention of sorghum residue cover on the soil surface reduced the seedling emergence of E. colona. Emergence was 70% in the absence of crop residue, whereas a residue amount of 8 t ha–1 reduced emergence to 47%. Emergence was greatest for seeds placed on the soil surface and declined linearly with increasing burial depth; no seedlings emerged from 8 cm depth. The GR biotype had higher germination than the GS biotype under high sodium chloride concentrations; therefore, this biotype may be highly competitive with crops under highly saline conditions. Because germination was high on the soil surface and was stimulated by light, this weed will remain problematic under no-till farming systems in Australia.

scholarly journals Plant Response to Saline Substrates V. Chloride Regulation in the Individual Organs of Hordeum Vulgare During Treatment with Sodium Chloride

1965 ◽  
Vol 18 (3) ◽  
pp. 505 ◽  
Author(s):  
H Greenway ◽  
DA Thomas
Keyword(s):  
Sodium Chloride ◽  
Hordeum Vulgare ◽  
Chloride Concentration ◽  
Plant Response ◽  
Sodium Chloride Concentration ◽  
High Sodium ◽  
The Individual ◽  
Chloride Regulation ◽  
Chloride Concentrations

This is a study on the regulation of chloride concentrations in H. vulgare at the early tillering stage, when grown on media of high sodium chloride concentration. 36CI was used during certain periods to determine retranslocation.

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