scholarly journals Characterization and Antibacterial Mode of a Novel Bacteriocin with Seven Amino Acids from Lactobacillus plantarum in Guizhou Salted Radish

2016 ◽  
Vol 8 (10) ◽  
pp. 120 ◽  
Author(s):  
Meizhong Hu ◽  
Lijuan Dang ◽  
Haizhen Zhao ◽  
Chong Zhang ◽  
Yingjian Lu ◽  
...  

<p>Traditional Chinese fermented vegetables are excellent probiotic food with probiotic lactic acid bacteria that are benefical to the health. A novel bacteriocin with molecular weight, 825 Da was found successfully from Lactobacillus plantarum 163, which was isolated from Guizhou salted radish. The complete amino acid sequence was speculated as YVCASPW based on the mass spectrometry, and was named as bacteriocin 163-1. The bacteriocin 163-1 was highly thermostable and stability over a broad pH range (pH 3-6), sensitive to protease K and pepsin, and exhibited a wide range of antimicrobial activity not only against lactic acid bacteria (LAB) but also against other foodborne pathogens including Gram-positive and Gram-negative bacteria. Bacteriocin 163-1 could disrupt the cell membrane of bacteria. The observations of the transmission electron microscopy and laser confocal microscopy on the cell membrane of Escherichia coli and Staphylococcus aureus showed that bacteriocin 163-1 could result in forming pores on the cell membrane and then cytolysis of the bacteria. The new bacteriocin with broad-spectrum antibacterial activity will be useful in preservation of vegetable, fruit and food as well agricultural bio-controlling.</p>

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Pasquale Russo ◽  
Maria Lucia Valeria de Chiara ◽  
Anna Vernile ◽  
Maria Luisa Amodio ◽  
Mattia Pia Arena ◽  
...  

Due to the increasing interest for healthy foods, the feasibility of using fresh-cut fruits to vehicle probiotic microorganisms is arising scientific interest. With this aim, the survival of probiotic lactic acid bacteria, belonging toLactobacillus plantarumandLactobacillus fermentumspecies, was monitored on artificially inoculated pineapple pieces throughout storage. The main nutritional, physicochemical, and sensorial parameters of minimally processed pineapples were monitored. Finally, probioticLactobacilluswere further investigated for their antagonistic effect againstListeria monocytogenesandEscherichia coliO157:H7 on pineapple plugs. Our results show that at eight days of storage, the concentration ofL. plantarumandL. fermentumon pineapples pieces ranged between 7.3 and 6.3 log cfu g−1, respectively, without affecting the final quality of the fresh-cut pineapple. The antagonistic assays indicated thatL. plantarumwas able to inhibit the growth of both pathogens, whileL. fermentumwas effective only againstL. monocytogenes. This study suggests that bothL. plantarumandL. fermentumcould be successfully applied during processing of fresh-cut pineapples, contributing at the same time to inducing a protective effect against relevant foodborne pathogens.


2013 ◽  
Vol 79 (19) ◽  
pp. 6059-6066 ◽  
Author(s):  
Arancha Hevia ◽  
Noelia Martínez ◽  
Víctor Ladero ◽  
Miguel A. Álvarez ◽  
Abelardo Margolles ◽  
...  

ABSTRACTAutoaggregation in lactic acid bacteria is directly related to the production of certain extracellular proteins, notably, aggregation-promoting factors (APFs). Production of aggregation-promoting factors confers beneficial traits to probiotic-producing strains, contributing to their fitness for the intestinal environment. Furthermore, coaggregation with pathogens has been proposed to be a beneficial mechanism in probiotic lactic acid bacteria. This mechanism would limit attachment of the pathogen to the gut mucosa, favoring its removal by the human immune system. In the present paper, we have characterized a novel aggregation-promoting factor inLactobacillus plantarum. A mutant with a knockout of the D1 gene showed loss of its autoaggregative phenotype and a decreased ability to bind to mucin, indicating an adhesion role of this protein. In addition, heterologous production of the D1 protein or an internal fragment of the protein, characterized by its abundance in serine/threonine, strongly induced autoaggregation inLactococcus lactis. This result strongly suggested that this internal fragment is responsible for the bioactivity of D1 as an APF. To our knowledge, this is the first report on a gene coding for an aggregation-promoting factor inLb. plantarum.


2008 ◽  
Vol 71 (10) ◽  
pp. 2024-2029 ◽  
Author(s):  
PONGSAK RATTANACHAIKUNSOPON ◽  
PARICHAT PHUMKHACHORN

Lactic acid bacteria isolated from various Thai fermented foods were screened for the presence of nisin gene by using PCR with primers specific to nisin A structural gene. Only one strain, Lactococcus lactis subsp. lactis TFF 221, isolated from kung jom, a traditional shrimp paste, was found to carry a nisin gene. The TFF 221 nisin had antimicrobial activity against not only closely related lactic acid bacteria but also some foodborne pathogens. It was heat stable and inactivated by α-chymotrypsin and proteinase K. Some characteristics of TFF 221 nisin were found to be very similar to those of nisin A produced by Lactococcus lactis subsp. lactis NCDO 2111. Both of them had the same antimicrobial spectrum and MICs against all indicator bacteria. However, when assayed with indicator organisms, in all cases the TFF 221 nisin produced larger zones of inhibition in agar diffusion assays than the nisin A did. Sequencing of the TFF 221 nisin gene showed that it was the natural nisin variant, nisin Z, as indicated by the substitution of asparagine residue instead of histidine at position 27. The nisin determinant in strain TFF 221 was found to be located on a conjugative transposon residing in the chromosome. The ability of the nisin produced by L. lactis subsp. lactis TFF 221 to inhibit a wide range of foodborne pathogens may be useful in improving the food safety of the fermented product, especially in the Thai environment, which suffers from perennial problems of poor food hygiene.


Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 963
Author(s):  
Jon Kepa Izaguirre ◽  
Leire Barañano ◽  
Sonia Castañón ◽  
Itziar Alkorta ◽  
Luis M. Quirós ◽  
...  

Soybeans and soy-based products contain isoflavones which can be used for nutraceutical and medical applications. In soybeans and in unfermented soy foods, isoflavones are normally present as glycosides. Isoflavone glycosides can be enzymatically converted to isoflavone aglycones, thus releasing the sugar molecule. The effective absorption of isoflavones in humans requires the bioconversion of isoflavone glycosides to isoflavone aglycones through the activity of the enzyme β-glucosidase. The objective was to assess the capacity of 42 bacterial strains (belonging to Lactobacillus, Streptococcus and Enterococcus) to produce β-glucosidase activity. The strain that showed the highest β-glucosidase activity (Lactobacillus plantarum 128/2) was then used for the optimization of the bioconversion of genistin and daidzin present in commercial soymilk to their aglycone forms genistein and daidzein. The contribution of process parameters (temperature, inoculum size, time) to the efficiency of such bioactivation was tested. Lactobacillus plantarum 128/2 was able to completely bioactivate soymilk isoflavones under the following conditions: 25 °C temperature, 2% inoculum size and 48 h process time. These results confirm the suitability of lactic acid bacteria for the bioactivation of isoflavones present in soymilk and provide an interesting candidate (L. plantarum 182/2) for food industries to perform this transformation.


2019 ◽  
Vol 7 (1) ◽  
pp. 1 ◽  
Author(s):  
Nurul Octavia Wasis ◽  
Nyoman Semadi Antara ◽  
Ida Bagus Wayan Gunam

Tabah bamboo shoot pickle is one of the fermented food which is the source of lactic acid bacteria.  Lactic acid bacteria (LAB) is beneficial to health because it has the ability as a probiotic. Lactic acid bacteria that have probiotic criteria should have resistance to low pH and bile salts. This study aims to determine isolates of lactic acid bacteria isolated from tabah bamboo shoot pickle resistant to low pH and bile salts (NaDC). Lactic acid bacteria were tested to low pH by using MRS broth that have different pH (pH 2, pH 3, pH 4 and pH 6.2 as a control) incubated at 37ºC for 3 hours. isolates were survive in low pH then continued in bile salt resistance test with 0.3% bile salt concentration for 15 minutes, 30 minutes, 45 minutes, 60 minutes and 24 hours. The results showed that three isolates out of 88 isolates had ability to grow in low pH and in medium supplemented by NaDC 0,3%. The isolates are AR 3057, AR 3101 and AR 6152 which can be used as candidat of  probiotic. Keywords : Tabah bamboo shoot pickle, lactic acid bacteria, probiotic, low pH, bile salt


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