scholarly journals How Capsular Exopolysaccharides Affect Cell Surface Properties of Lactic Acid Bacteria

2020 ◽  
Vol 8 (12) ◽  
pp. 1904
Author(s):  
Carsten Nachtigall ◽  
Cordula Vogel ◽  
Harald Rohm ◽  
Doris Jaros

Some lactic acid bacteria are able to produce exopolysaccharides that, based on localization, can be distinguished in free and capsular or cell-bound exopolysaccharides (CPS). Up to now, the former were the focus of current research, mainly because of the technofunctional benefits they exhibit on fermented dairy products. On the other hand, CPS affect the surface properties of bacteria cells and thus also the textural properties of fermented foods, but data are very scarce. As the cell surface properties are strongly strain dependent, we present a new approach to investigate the impact of CPS on cell surface hydrophobicity and moisture load. CPS positive and negative Streptococcus thermophilus and Weissella cibaria were subjected to ultrasonication suitable to detach CPS without cell damage. The success of the method was verified by scanning electron and light microscopy as well as by cultivation experiments. Before applying ultrasonication cells with CPS exhibiting an increased hydrophilic character, enhanced moisture load, and faster water adsorption compared to the cells after CPS removal, emphasizing the importance of CPS on the textural properties of fermented products. The ultrasonic treatment did not alter the cell surface properties of the CPS negative strains.

2010 ◽  
Vol 43 (6) ◽  
pp. 1594-1602 ◽  
Author(s):  
Mai Huong Ly-Chatain ◽  
Mai Linh Le ◽  
Mai Le Thanh ◽  
Jean-Marc Belin ◽  
Yves Waché

2007 ◽  
Vol 72 (3) ◽  
pp. M89-M93 ◽  
Author(s):  
M. Carmen Collado ◽  
Ingrid Surono ◽  
Jussi Meriluoto ◽  
Seppo Salminen

2009 ◽  
Vol 72 (8) ◽  
pp. 1699-1704 ◽  
Author(s):  
SUPAYANG PIYAWAN VORAVUTHIKUNCHAI ◽  
SAKOL SUWALAK

The effects of Quercus infectoria (family Fagaceae) nutgalls on cell surface properties of Shiga toxigenic Escherichia coli (STEC) were investigated with an assay of microbial adhesion to hydrocarbon. The surface of bacterial cells treated with Q. infectoria exhibited a higher level of cell surface hydrophobicity (CSH) toward toluene than did the surface of untreated cells. With 50% ethanolic extract, the CSH of the three strains of STEC O157:H7 treated with 4× MIC of the extract resulted in moderate or strong hydrophobicity, whereas at 2× MIC and MIC, the CSH of only one strain of E. coli O157:H7 was significantly affected. The 95% ethanolic extract had a significant effect on CSH of all three strains at both 4× MIC and 2× MIC but not at the MIC. The effect on bacterial CSH was less pronounced with the other STEC strains. At 4× MIC, the 50% ethanolic extract increased the CSH of all non-O157 STEC strains significantly. At 2× MIC and 4× MIC, the 95% ethanolic extract affected the CSH of E. coli O26:H11 significantly but did not affect E. coli O111:NM or E. coli O22. Electron microscopic examination revealed the loss of pili in the treated cells. The ability of Q. infectoria extract to modify hydrophobic domains enables this extract to partition the lipids of the bacterial cell membrane, rendering the membrane more permeable and allowing leakage of ions and other cell contents, which leads to cell death. Further studies are required to evaluate the effects of Q. infectoria extract in food systems or in vivo and provide support for the use of this extract as a food additive for control of these STEC pathogens.


Fermentation ◽  
2020 ◽  
Vol 6 (3) ◽  
pp. 91
Author(s):  
Gabriela Krausova ◽  
Antonin Kana ◽  
Ivana Hyrslova ◽  
Iva Mrvikova ◽  
Miloslava Kavkova

Selenized lactic acid bacteria (LAB) represent potentially safe and effective sources of selenium (Se), essential for human health, as lactic acid fermentation improves Se bioavailability and reduces its toxicity. LAB are generally recognized as safe (GRAS) and widely used in fermented dairy products. To facilitate selenized LAB implementation as a functional food, we developed and characterized new Se-enriched strains based on the food industry commercial strains Streptococcus thermophilus CCDM 144 and Enterococcus faecium CCDM 922A as representatives of two LAB genera. We evaluated Se bioaccumulation capacity, Se biotransformation and growth ability in the presence of different sodium selenite concentrations (0–50 mg/L), and antioxidant properties (2, 2-diphenyl-1-picrylhydrazyl (DPPH) method) and cell surface hydrophobicity between Se-enriched and parental strains in vitro. Sodium selenite addition did not negatively influence growth of either strain; thus, 50 mg/L was chosen as the optimal concentration based on strain accumulation capacity. Selenization improved the antioxidant properties of both strains and significantly increased their cell surface hydrophobicity (p < 0.05). To our knowledge, this represents the first report of Se-enriched strain hydrophobicity as well as the first on Se speciation in families Enterococcaceae and Streptococcaceae. Moreover, both tested strains demonstrated good potential for Se-enrichment, providing a foundation for further in vitro and in vivo studies to confirm the suitability of these Se-enriched strains for industrial applications.


2021 ◽  
Vol 9 (10) ◽  
pp. 2141
Author(s):  
Ji Young Jung ◽  
Sang-Soo Han ◽  
Z-Hun Kim ◽  
Myung Hoo Kim ◽  
Hye Kyeong Kang ◽  
...  

Lactic acid bacteria (LAB) are probiotic candidates that may restore the balance of microbiota populations in intestinal microbial ecosystems by controlling pathogens and thereby promoting host health. The goal of this study was to isolate potential probiotic LAB strains and characterize their antimicrobial abilities against pathogens in intestinal microbiota. Among 54 LAB strains isolated from fermented products, five LAB strains (NSMJ15, NSMJ16, NSMJ23, NSMJ42, and NFFJ04) were selected as potential probiotic candidates based on in vitro assays of acid and bile salt tolerance, cell surface hydrophobicity, adhesion to the intestinal epithelium, and antagonistic activity. Phylogenetic analysis based on 16S rRNA genes showed that they have high similarities of 99.58–100% to Lacticaseibacillus paracasei strains NSMJ15 and NFFJ04, Lentilactobacillus parabuchneri NSMJ16, Levilactobacillus brevis NSMJ23, and Schleiferilactobacillus harbinensis NSMJ42. To characterize their antimicrobial abilities against pathogens in intestinal microbiota, the impact of cell-free supernatant (CFS) treatment in 10% (v/v) fecal suspensions prepared using pooled cattle feces was investigated using in vitro batch cultures. Bacterial community analysis using rRNA amplicon sequencing for control and CFS-treated fecal samples at 8 and 16 h incubation showed the compositional change after CFS treatment for all five LAB strains. The changed compositions were similar among them, but there were few variable increases or decreases in some bacterial groups. Interestingly, as major genera that could exhibit pathogenicity and antibiotic resistance, the members of Bacillus, Escherichia, Leclercia, Morganella, and Vagococcus were decreased at 16 h in all CFS-treated samples. Species-level classification suggested that the five LAB strains are antagonistic to gut pathogens. This study showed the probiotic potential of the five selected LAB strains; in particular, their antimicrobial properties against pathogens present in the intestinal microbiota. These strains would therefore seem to play an important role in modulating the intestinal microbiome of the host.


2018 ◽  
Vol 2 (3) ◽  
pp. 35 ◽  
Author(s):  
Ewa Kaczorek ◽  
Amanda Pacholak ◽  
Agata Zdarta ◽  
Wojciech Smułek

The environment pollution with hydrophobic hydrocarbons is a serious problem that requires development of efficient strategies that would lead to bioremediation of contaminated areas. One of the common methods used for enhancement of biodegradation of pollutants is the addition of biosurfactants. Several mechanisms have been postulated as responsible for hydrocarbons bioavailability enhancement with biosurfactants. They include solubilization and desorption of pollutants as well as modification of bacteria cell surface properties. The presented review contains a wide discussion of these mechanisms in the context of alteration of bioremediation efficiency with biosurfactants. It brings new light to such a complex and important issue.


2019 ◽  
Vol 9 (6) ◽  
pp. 4591-4597

Fermented foods are high in nutrient content than any other category of foods due to the presence of live microorganisms called probiotics. Its application in manufacturing of dairy foods and role in different types of disease prevention ranks it as the most exuberant. The aim of the present study was to isolate and identify lactic acid bacteria from native curd samples collected from dairy farms of Odisha state of India and explore its probiotic potential. Three morphologically distinct bacterial strains were isolated using MRS agar plates. The biochemical study confirmed that all the isolates were gram-positive. The molecular approaches were used to analyze the taxonomical diversity of isolates. 16 S rRNA sequencing was carried out and the bacterial isolates were taxonomically classified as Lactobacillus sp., Lactobacillus plantarum, Lactobacillus casei with NCBI Gene bank accession number [MG573071], [MG573072] and [MG573073] respectively. Further, the isolated bacterial strains were screened for their acid and bile tolerance competence as a principal criterion for probiotic. Among the isolates Lactobacillus casei (MG573073) was found to be highly tolerant of low pH and bile salts, posed strongest cell surface hydrophobicity of 75%. However, the maximum zone of inhibition was observed against Amoxilline/clavunic acid 44mm. The cell growth was found higher in presence of 2% inulin with cell viability 9.11 log 10 CFU/ml. In conclusion, based on the obtained results, Lactobacillus casei can act as a suitable probiotic candidate.


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