The mechanism of iron uptake in Bacillus subtilis

1970 ◽  
Vol 16 (12) ◽  
pp. 1285-1291 ◽  
Author(s):  
W. J. Peters ◽  
R. A. J. Warren

A variety of phenolic compounds and hydroxamic acids reduced or prevented phenolic acid and coproporphyrin accumulation by iron-deficient cultures of Bacillus subtilis, but only if they were added to cultures with levels of iron which alone did not prevent accumulation. The compounds also increased iron uptake by iron-deficient cultures and norma) cultures. When radioactive catechol or 2,3-dihydroxybenzoic acid was used to increase iron uptake by iron-deficient cells, only very low levels of radioactivity remained associated with the cells. It is suggested that B. subtilis produces phenolic acids to solubilize iron; that other phenolic compounds or hydroxamic acids may substitute for the phenolic acids produced by B. subtilis; that the iron: phenolic acid complex does not enter the cell; and that the iron is removed from the complex at the cell surface and taken into the cell by an energy-dependent active transport system.

1971 ◽  
Vol 17 (1) ◽  
pp. 53-59 ◽  
Author(s):  
B. L. Walsh ◽  
W. J. Peters ◽  
R. A. J. Warren

Formation of the enzymes synthesizing 2,3-dihydroxybenzoic acid (DHB) in Bacillus subtilis is repressed by iron. DHB does not appear to be involved in regulating its own biosynthesis. Hemin may be involved in regulating DHB synthesis. DHB synthetase is inhibited by several m-substituted benzoic acids. The inhibitors do not affect the growth rate of B. subtilis and DHB appears not to be necessary for growth under the conditions used. Inhibition of DHB synthesis during growth under iron-deficient conditions reduces the iron uptake capacity of B. subtilis.


Foods ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 2798
Author(s):  
Simone Schefer ◽  
Marie Oest ◽  
Sascha Rohn

The understanding of interactions between proteins, carbohydrates, and phenolic compounds is becoming increasingly important in food science, as these interactions might significantly affect the functionality of foods. So far, research has focused predominantly on protein–phenolic or carbohydrate–phenolic interactions, separately, but these components might also form other combinations. In plant-based foods, all three components are highly abundant; phenolic acids are the most important phenolic compound subclass. However, their interactions and influences are not yet fully understood. Especially in cereal products, such as bread, being a nutritional basic in human nutrition, interactions of the mentioned compounds are possible and their characterization seems to be a worthwhile target, as the functionality of each of the components might be affected. This review presents the basics of such interactions, with special emphasis on ferulic acid, as the most abundant phenolic acid in nature, and tries to illustrate the possibility of ternary interactions with regard to dough and bread properties. One of the phenomena assigned to such interactions is so-called dry-baking, which is very often observed in rye bread.


Author(s):  
Peter K. Njenga ◽  
Samuel M. Mugo ◽  
Ting Zhou

Aim: The study aimed to characterize phenolic acids, flavonoids, and determine their antimicrobial activities in fruits of Vangueria madagascariensis (Tamarind of Indies). Study Design: The design of the study included picking of Vangueria madagascariensis fruits from Jomo Kenyatta University of Agriculture and Technology (JKUAT) botanical garden and analysis for their antimicrobial activities at the Botany department research laboratory, JKUAT. Characterization of phenolic acids and flavonoids were conducted at MacEwan University Canada. Place and Duration: JKUAT, Kenya and MacEwan University, Edmonton, Alberta Canada between June 2013 and June 2016. Methodology: Phenolic acids and flavonoids from Tamarind of Indies were determined by high-performance liquid chromatography coupled with photodiode array detection and electrospray ionization tandem mass spectrometry (HPLC-DAD-ESI-MSN). The antimicrobial assay was determined using the disk diffusion method. Results: Based on the retention time, the UV spectrum, and the tandem MS behavior, the results revealed a profile composed of 25 phenolic compounds. Some of the identified phenolic compounds included: 3-caffeoylquinic acid, 5-caffeoylquinic acid, 4-caffeoylquinic acid, 4-feruloyl quinic acid, quercetin 3-O-galactoside, quercetin 3-O-glucoside, quercetin, 3,4-di-caffeoylquinic acid, 4, 5-di-caffeoylquinic acid, kaempferol, diosmetin, caffeic acid, epicatechin, kaempferol 3-O-glucoside. The fruit extracts had a probable presence of quercetin 3-O-6’-malonylglucoside, ikarisoside C, epimedin C, unknown epigallocatechin-3-gallate and quercetin conjugate derivatives. Furthermore, the fruit extracts from Vangueria madagascariensis showed appreciable antimicrobial properties against human pathogen strains. Strong antimicrobial activity was observed for Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans. The Vangueria madagascariensis was found to be highly potent against Escherichia coli and Bacillus subtilis even at low concentrations of 0.1 mg/mL. Conclusion: The research findings may suggest value of the use of Vangueria madagascariensis fruits as a rich source of antioxidants with therapeutic and nutraceutical value.


2019 ◽  
Vol 86 (5) ◽  
Author(s):  
Gautam Gaur ◽  
Jee-Hwan Oh ◽  
Pasquale Filannino ◽  
Marco Gobbetti ◽  
Jan-Peter van Pijkeren ◽  
...  

ABSTRACT Phenolic acids are among the most abundant phenolic compounds in edible parts of plants. Lactic acid bacteria (LAB) metabolize phenolic acids, but the enzyme responsible for reducing hydroxycinnamic acids to phenylpropionic acids (HcrB) was only recently characterized in Lactobacillus plantarum. In this study, heterofermentative LAB species were screened for their hydroxycinnamic acid metabolism. Data on strain-specific metabolism in combination with comparative genomic analyses identified homologs of HcrB as putative phenolic acid reductases. Par1 and HcrF both encode putative multidomain proteins with 25% and 63% amino acid identity to HcrB, respectively. Of these genes, par1 in L. rossiae and hcrF in L. fermentum were overexpressed in response to hydroxycinnamic acids. The deletion of par1 in L. rossiae led to the loss of phenolic acid metabolism. The strain-specific metabolism of phenolic acids was congruent with the genotype of lactobacilli; however, phenolic acid reductases were not identified in strains of Weissella cibaria that reduced hydroxycinnamic acids to phenylpropionic acids. Phylogenetic analysis of major genes involved in hydroxycinnamic acid metabolism in strains of the genus Lactobacillus revealed that Par1 was found to be the most widely distributed phenolic acid reductase, while HcrB was the least abundant, present in less than 9% of Lactobacillus spp. In conclusion, this study increased the knowledge on the genetic determinants of hydroxycinnamic acid metabolism, explaining the species- and strain-specific metabolic variations in lactobacilli and providing evidence of additional enzymes involved in hydroxycinnamic acid metabolism of lactobacilli. IMPORTANCE The metabolism of secondary plant metabolites, including phenolic compounds, by food-fermenting lactobacilli is a significant contributor to the safety, quality, and nutritional quality of fermented foods. The enzymes mediating hydrolysis, reduction, and decarboxylation of phenolic acid esters and phenolic acids in lactobacilli, however, are not fully characterized. The genomic analyses presented here provide evidence for three novel putative phenolic acid reductases. Matching comparative genomic analyses with phenotypic analysis and quantification of gene expression indicates that two of the three putative phenolic acid reductases, Par1 and HcrF, are involved in reduction of hydroxycinnamic acids to phenylpropionic acids; however, the activity of Par2 may be unrelated to phenolic acids and recognizes other secondary plant metabolites. These findings expand our knowledge on the metabolic potential of lactobacilli and facilitate future studies on activity and substrate specificity of enzymes involved in metabolism of phenolic compounds.


1970 ◽  
Vol 16 (12) ◽  
pp. 1179-1185 ◽  
Author(s):  
W. J. Peters ◽  
R. A. J. Warren

Phenolic acids started to accumulate before coproporphyrin in cultures of B. subtilis grown under conditions of iron deficiency. If hemin synthesis was reduced or prevented, both phenolic acid accumulation and the iron-uptake capacity of the cells were decreased. A mutant strain unable to synthesize hemin accumulated phenolic acids only if the culture medium was extracted with hydroxyquinoline to remove residual iron. A mixture of iron and 2,3-dihydroxybenzoic acid was more effective than iron alone in reducing coproporphyrin accumulation by iron-deficient cultures. It is suggested that phenolic acids are produced by B. subtilis to solubilize the iron in the medium; under iron deficiency the biosynthetic pathway for phenolic acids is derepressed so that residual iron in the medium will be made available to the cell as the phenolic acid: iron complex.


1971 ◽  
Vol 17 (2) ◽  
pp. 213-216 ◽  
Author(s):  
B. L. Walsh ◽  
R. A. J. Warren

The iron-uptake system of S. typhimurium is energy-dependent, repressed by growth in the presence of iron, and apparently specific for iron. Iron uptake is stimulated by a sideramine and by phenolic acids. In mutants unable to synthesize enterobactin, the uptake system remains functional. Iron inside the cell is not available to external chelators.


Molecules ◽  
2020 ◽  
Vol 25 (23) ◽  
pp. 5627
Author(s):  
Agnieszka Krzymińska ◽  
Monika Gąsecka ◽  
Zuzanna Magdziak

The study focused on the determination of phenolic acids, flavonoids and organic acids in five tulip cultivars ‘Barcelona’, ‘Columbus’, ‘Strong Gold’, ‘Super Parrot’ and ‘Tropicana’. The cultivars grown in field and in a greenhouse were exposed after cutting to different times of storage (0, 3 and 6 days). The phenolic profile contained 4-hydroxybenzoic, 2,5-dihydroxybenzoic, gallic, vanillic, syringic, salicylic, protocatechuic, trans-cinnamic, p-coumaric, caffeic, ferulic, chlorogenic and sinapic acids, as well as quercetin, rutin, luteonin, catechin and vitexin. The mean phenolic acid content was in the following order: ‘Columbus’ and ‘Tropicana’ > ’Barcelona’ > ’Strong Gold’ > ’Super Parrot’, while the levels of flavonoids were as follows: ‘Strong Gold’ > ’Barcelona’ > ’Tropicana’ > ’Columbus’ > ’Super Parrot’. The highest content of phenolic acids was confirmed for Columbus and Tropicana, while the lowest was for Super Parrot. However total phenolic content was very similar, observed between the place of cultivation, time of storage and cultivars. Malonic, succinic, acetic and citric acids were the major organic acid components in tulip petals. More organic acids (except malonic) were accumulated in tulip petals from fields than those from the greenhouse, while changes during storage were strictly correlated with cultivars.


2012 ◽  
Vol 63 (2) ◽  
pp. 149-154 ◽  
Author(s):  
Małgorzata Materska ◽  
Irena Perucka

The aim of the present work was to determine differences in <i>C</i> and <i>O</i> glycosides of flavonoids, derivatives of phenolic acids, as well as capsaicinoid content in two semi-hot pepper cultivars, cv. Tornado and Tajfun. Fruits were harvested at the green and red maturity stages. Flavonoid and capsaicinoid fractions were isolated on Sep-Pak C18 cartridges with 40% and 70% methanol-water solutions, respectively. The chemical composition of both fractions was determined by HPLC method using standards of phenolic compounds obtained in the earlier work and the capsaicin standard. The flavonoid fraction contained glucose esters of phenolic acid, mainly ferulic and sinapic acid, as well as derivatives of flavonoids, quercetin, luteolin and apigenin, which occurred as <i>O</i>- and <i>C</i>- glycosides with glucose, rhamnose, and apiose. The capsaicinoid fraction contained mainly capsaicin and dihydrocapsaicin. It was found that in green fruits flavonoid <i>O</i>-glycosides were the predominant phenolics, while in red ones derivatives of phenolic acids. A higher loss of <i>O</i>-glycosides of flavonoids than of <i>C</i>-glycosides was observed during the maturation of the fruit of semi-hot pepper cultivars.


2013 ◽  
Vol 59 (No. 7) ◽  
pp. 288-294 ◽  
Author(s):  
J. Malá ◽  
M. Cvikrová ◽  
M. Hrubcová ◽  
P. Máchová

The study described in this paper was undertaken in order to assess the impact of different woody plants on the dynamics of phenolic acids in soil. The influence of plant litter on the amount of phenolic compounds occurring in soils beneath several deciduous and coniferous tree species was examined in pot experiments. The contents of endogenous methanol soluble free and conjugated phenolic acids in Norway spruce, larch, rowan and two species of willow were determined. We focused on the dynamics of water-soluble and reversibly bound phenolic acid contents in the upper layers of soil substrates in pots after the cultivation of studied woody plants. &nbsp; &nbsp;


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