Analysis of promoter sequences from Lactobacillus helveticus CNRZ32 and their activity in other lactic acid bacteria

2005 ◽  
Vol 98 (1) ◽  
pp. 64-72 ◽  
Author(s):  
Y.-S. Chen ◽  
J.L. Steele
Microscopy ◽  
2020 ◽  
Vol 69 (5) ◽  
pp. 286-290
Author(s):  
Takamichi Kamigaki ◽  
Akihiro Ogawa

Abstract Some species of lactic acid bacteria used for the production of natural cheese produce exopolysaccharides (EPS). Electron microscopy is useful for analyzing the microstructure of EPS produced by lactic acid bacteria. However, pretreatments used to observe the microstructure of EPS by electron microscopy, such as dehydration and resin embedding, can result in EPS flowing out easily from the cell. Therefore, in this study, the Tokuyasu method was conducted on cryosection to reduce EPS outflow. Two types of observation method, namely, using lectin and ruthenium red, were conducted in an attempt to observe EPS produced by Lactobacillus helveticus SBT2171. Observation using the lectin method confirmed that colloidal gold particles conjugated with a lectin recognizing β-galactoside were present in the capsule. Structures that appeared to be β-galactoside-containing slime polysaccharides that were released from the cell wall were also observed. Observation using ruthenium red showed that capsular polysaccharides (CPS) in the capsule were present as a net-like structure. Colloidal gold conjugation with an anti-β-lactoglobulin antibody, in addition to ruthenium red staining, allowed the identification of slime polysaccharides released from the cell wall in the milk protein network derived from the culture medium. Based on these results, the Tokuyasu method was considered to be a useful pretreatment method to clarify and observe the presence of EPS. In particular, both CPS in the capsule and slime exopolysaccharides released from the cell wall were visualized.


1999 ◽  
Vol 66 (1) ◽  
pp. 105-113 ◽  
Author(s):  
ANNE THIERRY ◽  
DELPHINE SALVAT-BRUNAUD ◽  
JEAN-LOUIS MAUBOIS

Swiss-type cheeses such as Emmental are characterized by the successive development of thermophilic lactic acid bacteria (TLAB) and propionibacteria. The aim of this study was to determine whether the choice of TLAB strain influenced propionibacteria. TLAB and propionibacteria were cultured sequentially under the conditions prevailing in cheese. Firstly, 11 Emmental juice-like media were prepared by fermenting casein-enriched milk with pure or mixed cultures of TLAB (Lactobacillus helveticus, Lb. delbrueckii subsp. lactis and Streptococcus thermophilus), differing in their proteolytic activities. TLAB cells were then removed by microfiltration. Finally, five strains of Propionibacterium freudenreichii were grown on these media at 24°C under anaerobiosis and their growth characteristics and lactate consumption determined. The media mainly differed in their contents of peptides (1·9–5·3 g/kg) and free amino acids (1·0–5·6 g/kg) and the proportions of lactate isomers (42–92% of the L(+) isomer). Propionibacteria were significantly (P<0·05) influenced by TLAB strains (differences in doubling times of up to 20% and differences in lactate consumption after 600 h culture of up to 52%). The influence of TLAB was similar for all the propionibacteria tested, depended on the TLAB strains and could not be generalized to the TLAB species. Propionibacteria were stimulated by high peptide levels, low levels of free amino acids and NaCl, a low proportion of L(+)-lactate and other undetermined factors. However, variations due to TLAB were less than those between propionibacteria strains.


Foods ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 586
Author(s):  
Heba Mostafa

To produce a new probiotic-containing food product, potato chips, as the most preferred fast food, were chosen. Preferably, it should be preserved for a long period without oxidation. The presented study aimed to compare potato chips containing two lyophilized probiotic lactic acid bacteria (Bifidobacterium longum ATCC 15708 and Lactobacillus helveticus LH-B02) in order to retard lipid oxidation. Lyophilization of probiotics was carried out into two cryoprotective media—skim milk (SM) and gelatin/glycerol (GG) as lactose-free medium. Results revealed that GG and SM media were the most suitable for lyophilization of B. longum and L. helveticus, respectively. The lyophilized live cells were incorporated in potato chips, packed and their effect on oil oxidation was assessed. Results showed that the lyophilized B. longum in SM remained alive at 6.5 log CFU/g for 4 months at 30 °C. Interestingly, potato chip bags containing B. longum lyophilized in SM medium exhibited a decrease in peroxide value (PV) and acid value (AV) of the extracted oil by 40.13% and 25%, respectively, compared to the control bags. The created probiotic potato chips containing B. longum fulfill the criteria of the probiotic product besides the prime quality and sensory attributes.


2011 ◽  
Vol 2 (4) ◽  
pp. 335-339 ◽  
Author(s):  
N. Karapetkov ◽  
R. Georgieva ◽  
N. Rumyan ◽  
E. Karaivanova

Five lactic acid bacteria (LAB) strains belonging to species Lactobacillus acidophilus, Lactobacillus helveticus, Lactobacillus delbrueckii subsp. bulgaricus, Lactobacillus delbrueckii subsp. lactis and Streptococcus thermophilus were tested for their susceptibility to 27 antibiotics. The minimum inhibitory concentrations of each antimicrobial were determined using a microdilution test. Among the strains a high susceptibility was detected for most of the cell-wall synthesis inhibitors (penicillins, cefoxitin and vancomycin) and resistance toward inhibitors of DNA synthesis (trimethoprim/sulfonamides and fluoroquinolones). Generally, the Lactobacillus strains were inhibited by antibiotics such as chloramphenicol, erythromycin and tetracycline at breakpoint levels lower or equal to the levels defined by the European Food Safety Authority. Despite the very similar profile of S. thermophilus LC201 to lactobacilli, the detection of resistance toward erythromycin necessitates the performance of additional tests in order to prove the absence of transferable resistance genes.


2006 ◽  
Vol 73 (3) ◽  
pp. 264-272 ◽  
Author(s):  
Salvatore Coppola ◽  
Vincenzina Fusco ◽  
Rosamaria Andolfi ◽  
Maria Aponte ◽  
Giuseppe Blaiotta ◽  
...  

Microbial diversity of the raw milk for the production of Fior di Latte di Agerola and its changes during cheesemaking were studied. Viable counts showed that at the end of curd ripening, loads of lactic acid bacteria, both mesophilic and thermophilic rods and cocci, higher than those commonly evidenced in similar cheeses produced by using natural or commercial starters, were detected. Identification of 272 isolates, supported by molecular diagnostic aids, evidenced representative cultures of a high number of bacterial taxa of interest as participating in the process, although most of the isolates belonged to Lactococcus lactis and Lactobacillus helveticus species. RAPD-PCR and REA-PFGE biotyping were performed for the isolates of the above species and it was shown that most of the strains isolated from the raw milk occurred during the whole cheesemaking process, and an active role of these strains in the fermentation was supposed. The results offer further proof of the importance of the raw milk as source of technologically interesting strains of lactic acid bacteria capable of driving the fermentation of traditional cheeses.


Microbiology ◽  
2009 ◽  
Vol 155 (5) ◽  
pp. 1726-1737 ◽  
Author(s):  
Takaomi Wada ◽  
Masafumi Noda ◽  
Fumi Kashiwabara ◽  
Hyung Joon Jeon ◽  
Ayano Shirakawa ◽  
...  

In this study we isolated over 250 lactic acid bacteria (LAB) candidates from fruit, flowers, vegetables and a fermented food to generate an LAB library. One strain, designated 925A, isolated from kimchi (a traditional Korean fermented dish made from Chinese cabbage) produced a novel type of bacteriocin, brevicin 925A, which is effective against certain LAB, including strains of Lactobacillus, Enterococcus, Streptococcus, Bacillus and Listeria. Strain 925A, identified as Lactobacillus brevis, harboured at least four plasmids and we determined the entire nucleotide sequence of each one. The four plasmids were designated pLB925A01–04, and have molecular sizes of 1815, 3524, 8881 and 65 037 bp, respectively. We obtained bacteriocin non-producing derivatives by treatment of strain 925A with novobiocin. All of these derivatives, which were susceptible to their own antibacterial product, lost the largest plasmid, pLB925A04, suggesting that the genes for bacteriocin biosynthesis (breB and breC) and immunity (breE) are located on pLB925A04. The partial amino acid sequence of purified brevicin 925A and sequence analysis of pLB925A04 showed that breB is the structural gene for brevicin 925A. We constructed a shuttle vector (pLES003, 6134 bp) that can replicate in both Escherichia coli and LAB such as Lactobacillus plantarum, Lb. brevis, Lactobacillus helveticus, Lactobacillus hilgardii and Enterococcus hirae. To determine the function of gene breE, which displays no significant similarity to any other sequences in the blast search database, the gene was inserted into pLES003. A pLB925A04-cured derivative transformed with pLES003 carrying breE acquired immunity to brevicin 925A, suggesting that breE encodes an immunity protein.


1972 ◽  
Vol 35 (8) ◽  
pp. 489-495 ◽  
Author(s):  
H. s. Park ◽  
E. H. Marth

Cultured skimmilks containing Salmonella typhimurium were prepared at 21, 30, or 42 C using different species of lactic acid bacteria (0.25, 1.0, and 5% inoculum) either singly or in combinations. Several commercial cultures also were used. Cultured skimmilks were stored at 11 C and tested at 3-day intervals for numbers of viable salmonellae and lactic acid bacteria and for pH. Survival of S. typhimurium varied from 6 to 9 days and from 3 to 6 days in milks cultured with 0.25% Streptococcus lactis at 21 and 30 C, respectively. Increasing the inoculum to 1% with incubation at 30 C yielded a product no more detrimental to S. typhimurium than when the lower inoculum was used at 30 C. Survival of S. typhimurium always exceeded 9 days when S. cremoris was used to make cultured skimmilks. Products made with commercial mixed cultures composed of S. lactis and S. cremoris allowed S. typhimurium to survive for periods intermediate between the extremes observed when pure cultures were used. Skimmilks cultured with Streptococcus diacetilactis and Leuconostoc citrovorum, even when skimmilks cultured with the latter organism were acidified with citric acid and incubated further, were essentially without effect on survival of S. typhimurium during refrigerated storage. Use of Streptococcus thermophilus (1% culture, 42 C incubation) yielded cultured skimmilks that were most detrimental to survival of salmonellae, whereas skimmilks fermented with Lactobacillus bulgaricus permitted survival of low numbers of salmonellae beyond 9 days. Milks cultured at 42 C with a 5% inoculum of S. thermophilus mixed with L. bulgaricus or Lactobacillus helveticus were free of viable salmonellae before the incubation was complete. Salmonellae grown in skimmilk at 21 C without a lactic culture were more resistant to inactivation during refrigerated storage than was S. typhimurium grown at 30 or 42 C.


2020 ◽  
Vol 8 (3) ◽  
pp. 152 ◽  
Author(s):  
Paula Martins Olivo ◽  
Monica Regina da Silva Scapim ◽  
Luciana Furlaneto Maia ◽  
Juliana Miazaki ◽  
Bruna Moura Rodrigues ◽  
...  

Edible films have been employed to improve the food quality. Thus, the objective of this study was to evaluate the edible coverage as a vehicle for probiotics bacteria in cheeses. The experimental design was completely randomized containing four treatments: uncoated cheeses, sodium alginate coated cheeses, sodium alginate + Lactobacillus acidophilus coated cheeses and sodium alginate + Lactobacillus helveticus coated cheeses, analysed for 15 days. The parameters of water steam permeability, thickness and Young's modulus were significant. In the simulation of gastrointestinal conditions, there was a reduction in lactic acid bacteria. There was a reduction in coliform values in coated cheeses. In the identification using Random Amplified Polymorphic DNA technique, Lactobacillus helveticus strains were isolated, suggesting the microorganism migration to inside the cheese. Scanning electron microscopy showed that the lactic acid bacteria were distributed throughout the surface of the edible coating. It suggested the Lactobacillus helveticus permeability added in the cover to the cheese interior, ensuring that the cover can be a vehicle for dairy bacteria.


Author(s):  
SM Amanullah ◽  
MA Kabir ◽  
MM Rahman ◽  
P Halder ◽  
SMJ Hossain ◽  
...  

This research was conducted to study the types of lactic acid bacteria (LAB) present in selected yogurts available in the local market of Bangladesh. For this purpose, nine different yogurt samples were collected (viz. MV, Mw, Pst, Psr, Bik, Bog, WF, Kw and Nab) and cultured in the selective MRS agar media for enumerating LAB colony. Out of 9 samples, colony forming LAB were found in 6 samples and the population ranged from 1.0×104 to 9.5×105 cfu/ml. Catalase negative and Gram’s positive colonies were initially identified as LAB. Then the isolates were purified by subsequent culturing in MRS broth and MRS agar media. Biochemical properties of selected colonies were evaluated by performing gas production from glucose, growth at different temperatures (10ºC, 15ºC and 45ºC), growth at different NaCl concentrations (2, 4 and 6.5% NaCl) and sugar fermentation tests (lactose, sorbitol, salicin, trehalose, melibiose, sucrose, mannitol, melezitose, maltose, galactose, glucose, arabinose, raffinose and ribose). According to the tests stated above, a total of five different species of LAB were identified from 6 samples. The isolate Lactobacillus lactis was identified in MV, PSr and Bog yogurt, while Lactobacillus bulgaricus was found in MV and Bik yogurt. The species Leuconostoc cremoris, a avor producing bacteria, was found in six yogurt samples. On the other hand, Lactobacillus acidophilus and Lactobacillus helveticus was found only in Pst and Psr samples, respectively. Bang. J. Livs. Res. Vol. 27 (1&2), 2020: P. 64-72


2021 ◽  
Vol 32 (1) ◽  
pp. 12-20
Author(s):  
Demberel Shirchin ◽  
Ulzii-Uchral Davaasuren ◽  
Tsogtbaatar Lkhagvajav ◽  
Bulgan Boldbaatar

We studied some biological properties of the local strains Lactobacillus helveticus LBMA44c and Lactobacillus delbruesckii subsp.bulgaricus LBMA65b contained in the domestic probiotic LACTOSA in compared to imported probiotics Lactobacillus, Linex-malysh and Acidophilus Probiotic Blend.  The strains cultivated in liquid and solid selective MRS medium, obtained as a result of subsequent dilutions of a sample of the probiotics under study, perfectly demonstrated the general features of the morphological and cultural properties of lactic acid bacteria. The authors found that the indicators CFU/g of  LACTOS (1.9-2.0x108 CFU/g) is not less than that of imported ones, in terms of the oxidation of nutrient media, it is the same as that of Acidophilus Probiotic Blend-and slightly lower than that of Linex and Lacto-Fit. Strains of lactic acid bacteria in all studied probiotics are well cultivated at 37, 45, 60 degrees (0C) and on a selective medium with an addition at the rate of 2, 4, 6 percent of natural bile and grows poorly on a medium with the addition of 4 and 6 percent NaCl. We also noted that the local strains in our LACTOS probiotic were relatively more resistant to antibiotics than imported ones, according to antibiotic resistance estimates. Thus, the local strains of lactic acid bacteria contained in the domestic probiotic under the LACTOS trademark do not differ from the imported ones. “Лактос” пробиотикт агуулагдах сүүн хүчлийн бактерийн шинж чанарыг импортынхтой харьцуулсан судалгаа “Лактос” пробиотикт агуулагдах сүүн хүчлийн бактерийн Lаctobacillus helveticus LBMA44c болон Lаctobacillus delbruesckii subsp.bulgaricus LВMА65b нутгийн омгийн эмнэлэг-биологийн чадавхын зарим үзүүлэлтийг импортын Lасто-Fit, Линекс Малыш №20, Acidophilus Probiotic Blend-ийнхтэй харьцуулан судлав. Судалгаанд хамрагдсан пробиотикуудын дээжний шингэлэлтээс MRS -ийн хатуу, шингэн сонгомол орчинд ургуулахад тэдгээр нь сүүн хүчлийн бактерийн өсгөвөржилт, хэлбэр зүйн нийтлэг шинж байдлыг үзүүлжээ. Пробиотикт агуулагдах амилах чадвартай бактерийн эсийн тоогоор Лактосынх (1,9-2,0х108КҮН/г) импортынхоос дутахгүй, харин орчныг хүчилсэг болгох идэвхээрээ Линекс Малыш, Lасtо-Fit-ээс бага зэрэг доогуур Acidophilus Probiotic Blend -тэй ойролцоо байна. Тэдгээр нь Цельсийн 37, 45, 60 хэмийн дулаанд болон 2, 4, 6 хувиар цөс нэмсэн тэжээлт орчинд сайн өсгөвөржих боловч цэвэр NaCl-ийн нэмэлт 4-6 хувь хүрэхэд пробиотикийн агууламж дахь сүүн хүчлийн бактерийн ургалтын эрчим дундаас доош гэсэн үнэлэмж рүү шилжсэн юм. Лактост агуулагдах сүү хүчлийн бактерийн омгууд нь судалгаанд ашигласан 5 төрлийн антибиотик тэсвэрлэх чадавхын дундаж үзүүлэлтээр импортын пробиотикийнхтой ойролцоо ажээ.  Түлхүүр үг: пробиотик, сүүн хүчлийн бактери, тэсвэрт чанар, өсгөвөржилт


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