scholarly journals Ιn Vitro Screening of γ-Aminobutyric Acid and Autoinducer-2 Signalling in Lactic Acid Bacteria Exhibiting Probiotic Potential Isolated from Natural Black Conservolea Olives

Foods ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 640 ◽  
Author(s):  
Foteini Pavli ◽  
Eleni Gkana ◽  
Oluwabunmi Adebambo ◽  
Kimon-Andreas Karatzas ◽  
Efstathios Panagou ◽  
...  

In the present study, 33 strains of lactic acid bacteria (LAB) previously isolated from natural black Conservolea olives were assessed for their probiotic potential in vitro, as well as for their autoinducer-2 (AI-2) activity under standard growth conditions and the production of γ-aminobutyric acid (GABA). The probiotic tests included the in vitro resistance to low pH and resistance to bile salts, the evaluation of bile salt hydrolase activity, as well as safety tests regarding their possible haemolytic activity and their antimicrobial activity against pathogens. The results indicated that 17 strains were able to survive in low pH and in the presence of bile, with 15 of them also exhibiting partial bile salt hydrolase activity. None of the strains exhibited haemolytic activity or inhibited the growth of any of the examined pathogens. Moreover, the strains displayed generally low AI-2 activity under the growth conditions tested, regardless of the species. Interestingly, in contrast to what has been found in most foods, none of the isolates were found to produce GABA after 48 h of growth. The results from the AI-2 activity and extracellular GABA detection were considered as unexpected for LAB with probiotic attributes.

2014 ◽  
Vol 7 (1) ◽  
pp. 38-43
Author(s):  
Eva Hybenová ◽  
Lucia Birošová ◽  
Kristína Nagyová ◽  
Júlia Štofirová ◽  
Nikoleta Šaková ◽  
...  

Abstract The aim of this work was to evaluate presence and properties of lactic acid bacteria in the faeces of 240 volunteers with various nutrition habits (vegetarians versus meat-eaters). Lactic acid bacteria counts in all age groups were nearly 5 or 6 logarithmic orders. Significantly higher amounts were found in women. Subsequently, based on the age and dietary pattern of probands, four samples were selected for isolation of lactic acid bacteria and identification of isolates in order to assign them to bacterial species. About 80 lactic acid bacteria were isolated from the faeces of young (21-30 years) and older (51-60 years) vegetarians and meateaters. The identification of the isolates was based on their morphological and biochemical characteristics. Isolates belong to lactobacilli, bifidobacteria, enterococci and propionibacteria. Surprisingly, bifidobacteria were predominated in older age group. The following probiotic properties were determined: survival at low pH value, and bile salt hydrolase activity. All strains were negative in bile salt hydrolase activity, but their growth was not inhibited in the presence of bile. The results from the study of survival at low pH value showed considerable variability in both dietary groups regardless the age of probands. However, it can be concluded, that bacteria isolated from the samples of older probands were more sensitive to acid pH.


Author(s):  
Y. Zeng ◽  
Y. Li ◽  
Q. P. Wu ◽  
J. M. Zhang ◽  
X. Q. Xie ◽  
...  

This study investigated the antipathogenic activity and probiotic potential of indigenous lactic acid bacteria (LAB) isolated from Chinese homemade pickles. In total, 27 samples were collected from different sites in China. Fifty-nine yielded pure colonies were identified by 16S rRNA gene sequencing as LAB and were initially evaluated for the antibacterial activity in vitro. Initial screening yielded Lactobacillus plantarum GS083, GS086, and GS090, which showed a broad-spectrum antibacterial activity against food-borne pathogens, especially multidrug-resistant pathogens. Meanwhile, organic acids were mainly responsible for the antimicrobial activity of the LAB strains, and the most abundant of these was lactic acid (19.32 ± 0.95 to 24.79 ± 0.40 g/l). Additionally, three L. plantarum strains demonstrated several basic probiotic characteristics including cell surface hydrophobicity, autoaggregation, and survival under gastrointestinal (GI) tract conditions. The safety of these isolates was also evaluated based on their antibiotic susceptibility, hemolytic risk, bile salt hydrolase activity, and existence of virulence or antibiotic resistance genes. All strains were safe at both the genomic and phenotypic levels. Therefore, L. plantarum GS083, GS086, and GS090 are fairly promising probiotic candidates and may be favorable for use as preservatives in the food industry.


2020 ◽  
Vol 9 (8) ◽  
pp. e266984958
Author(s):  
Cristiane Pereira de Lima ◽  
Giselle Maria Pereira Dias ◽  
Maria Taciana Cavalcanti Vieira Soares ◽  
Laura Maria Bruno ◽  
Ana Lucia Figueiredo Porto

The aim of this study was to characterize the probiotic potential of 24 lactic acid bacteria (LAB) strains isolated from artisanal Coalho cheese from Pernambuco, Brazil by in vitro tests. The gastrointestinal tract (GIT) resistance, antimicrobial activity against intestinal pathogens, autoaggregation and coaggregation capacity, cell hydrophobicity, ß-galactosidase activity, deconjugate bile salt activity for the production of bile salt hydrolase (BSH), and the sensitivity to antibiotics were evaluated. Of the 24 strains, 22 remained viable to a simulated GIT. Two LAB inhibited the growth of Listeria monocytogenes and two inhibited Escherichia coli. The autoaggregation rate ranged from 27% to 96%, and the strains were able to coaggregate with Staphylococcus aureus and E. coli reaching levels between 58% and 47%, respectively. The hydrophobicity percentage ranged from 5% to 57%. Four strains were able to produce BSH. One LAB was able to produce up to 604 Miller units of ß-galactosidase. All strains were sensitive to five antibiotics and only two were resistant to vancomycin (30μg) and norfloxacin (10g). LAB strains which were able to overcome all barriers with a reduction of only one log cycle and LAB strains which were able to produce ß-galactosidase were identified by 16S rRNA sequence analysis as Lactococcus lactis subsp. Lactis, Enterococcus durans, and Enterococcus faecium. The evaluated LAB showed promising probiotic characteristics. Strains identified as L. lactis subsp. Lactis were selected for studies involving their technological potential to investigate the possible use of these microorganisms into a functional product.


2016 ◽  
Vol 79 (11) ◽  
pp. 1919-1928 ◽  
Author(s):  
SHUANG XU ◽  
TAIGANG LIU ◽  
CHIRAZ AKOREDE IBINKE RADJI ◽  
JING YANG ◽  
LANMING CHEN

ABSTRACT In this study, we analyzed Chinese traditional fermented food to isolate and identify new lactic acid bacteria (LAB) strains with novel functional properties and to evaluate their cellular antioxidant and bile salt hydrolase (BSH) activities in vitro. A sequential screening strategy was developed to efficiently isolate and obtain 261 LAB strains tolerant of bile salt, acid, and H2O2 from nine Chinese traditional fermented foods. Among these strains, 70 were identified as having 2,2-diphenyl-1-picrylhydrazyl radical scavenging and/or BSH activity. These strains belonged to eight species: Enterococcus faecium (33% of the strains), Lactobacillus plantarum (26%), Leuconostoc mesenteroides (14%), Pediococcus pentosaceus (6%), Enterococcus durans (9%), Lactobacillus brevis (9%), Pediococcus ethanolidurans (3%), and Lactobacillus casei (1%). The pulsed-field gel electrophoresis genome fingerprinting profiles of these strains revealed 38 distinct pulsotypes, indicating a high level of genomic diversity among the tested strains. Twenty strains were further evaluated for hydroxyl radical scavenging activity, reducing power, and ferrous ion chelating activity exerted by both viable intact cells and/or intracellular cell-free extracts. Some strains, such as L. plantarum D28 and E. faecium B28, had high levels of both cellular antioxidant and BSH activities in vitro. These strains are promising probiotic components for health-promoting functional foods.


2012 ◽  
Vol 34 (8) ◽  
pp. 1511-1518 ◽  
Author(s):  
Ana Yanina Bustos ◽  
Lucila Saavedra ◽  
Graciela Font de Valdez ◽  
Raúl Ricardo Raya ◽  
María Pía Taranto

2015 ◽  
Vol 9 (1) ◽  
pp. 61-66 ◽  
Author(s):  
Gundega Gulbe ◽  
Anda Valdovska ◽  
Vaira Saulite ◽  
Jevgenijs Jermolajevs

Probiotic lactic acid bacteria have a great potential to control bovine mastitis as well as they are favourable choice to treat many infectious diseases of human. These bacteria are well known as having many properties which make them beneficial to control pathogenic microorganisms. These include, the ability to adhere to cell, the reduction of pathogenic bacteria adherents, the co–aggregation, the production of organic acids, hydrogen peroxide, bacteriocin and etc., to be safe and non–pathogenic, which antagonize pathogenic microorganisms. However, each strain must be well identified and characterized in vitro before using for disease treatment. The aim of the present study was to screen three kind of test suspensions: TS1, TS2 and TS3, which contains probiotic lactic acid bacterium Lactobacillus helveticus or its natural glycopeptides, and other natural immunomodulators, in order to investigate which content were the most effective in inhibiting several mastitis causing bacteria in dairy cattle: coagulase–positive Staphylococcus aureus, coagulase–negative staphylococci S. haemolyticus, S. saprophyticus, S. simulans, S. vitulinus, and Gram–negative bacteria Citrobacter freundii and Serratia liquefaciens. Test suspensions TS1, TS2 and TS3 were adjusted by pH 6.3, then tested in vitro by well diffusion assay to determine their antimicrobial effect against bacteria. Furthermore haemolytic activity of applied test suspensions were determined. In results TS1 (9-13 mm) and TS2 (10-15 mm) showed the inhibition effect on four of eight tested bacterial strains, whereas TS3 did not displayed any antimicrobial effect. TS2 have a greatest antimicrobial activity as they resulted in the largest inhibition zones.


2019 ◽  
Vol 7 (12) ◽  
pp. 709 ◽  
Author(s):  
Jihen Missaoui ◽  
Dalila Saidane ◽  
Ridha Mzoughi ◽  
Fabio Minervini

Microorganisms inhabiting fermented foods represent the main link between the consumption of this food and human health. Although some fermented food is a reservoir of potentially probiotic microorganisms, several foods are still unexplored. This study aimed at characterizing the probiotic potential of lactic acid bacteria isolated from zgougou, a fermented matrix consisting of a watery mixture of Aleppo pine′s seeds. In vitro methods were used to characterize the safety, survival ability in typical conditions of the gastrointestinal tract, and adherence capacity to surfaces, antimicrobial, and antioxidant activities. Strains belonged to the Lactobacillus plantarum group and Enterococcus faecalis showed no DNase, hemolytic, and gelatinase activities. In addition, their susceptibility to most of the tested antibiotics, satisfied some of the safety prerequisites for their potential use as probiotics. All the strains tolerated low pH, gastrointestinal enzymes, and bile salts. They displayed a good antibacterial activity and antibiofilm formation against 10 reference bacterial pathogens, especially when used as a cell-free supernatant. Furthermore, the lactic acid bacteria (LAB) strains inhibited the growth of Aspergillus flavus and Aspergillus carbonarius. Finally, they had good antioxidant activity, although depending on the strain. Overall, the results of this work highlight that zgougou represents an important reservoir of potentially probiotic LAB. Obviously, future studies should be addressed to confirm the health benefits of the LAB strains.


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