Transposition in Lactobacillus delbrueckii subsp. bulgaricus: identification of two thermosensitive replicons and two functional insertion sequences

Microbiology ◽  
2003 ◽  
Vol 149 (6) ◽  
pp. 1503-1511 ◽  
Author(s):  
Pascale Serror ◽  
Golnar Ilami ◽  
Hichem Chouayekh ◽  
S. Dusko Ehrlich ◽  
Emmanuelle Maguin

In this report, it is shown that the rolling circle replicon pG+host and the theta replicon pIP501 are thermosensitive in Lactobacillus delbrueckii subsp. bulgaricus (Lactobacillus bulgaricus). Using a pIP501 derivative as a delivery vector for six insertion sequences originating from lactic acid bacteria, it is shown that IS1223 and IS1201 transpose in L. bulgaricus.

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.


2012 ◽  
Vol 58 (5) ◽  
pp. 581-588 ◽  
Author(s):  
Jonathan Emiliano Laiño ◽  
Jean Guy LeBlanc ◽  
Graciela Savoy de Giori

Folate is a B-group vitamin that cannot be synthesized by humans and must be obtained exogenously. Although some species of lactic acid bacteria (LAB) can produce folates, little is known about the production of this vitamin by yogurt starter cultures. Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus strains were isolated from artisanal Argentinean yogurts and were grown in folate-free culture medium (FACM) and nonfat milk after which intracellular and extracellular folate production were evaluated. From the initial 92 isolated LAB strains, 4 L. delbrueckii subsp. bulgaricus and 32 S. thermophilus were able to grow in the absence of folate. Lactobacillus delbrueckii subsp. bulgaricus CRL 863 and S. thermophilus CRL 415 and CRL 803 produced the highest extracellular folate levels (from 22.3 to 135 µg/L) in FACM. In nonfat milk, these strains were able to increase the initial folate concentrations by almost 190%. This is the first report where native strains of L. delbrueckii subsp. bulgaricus were shown to produce natural folate. The LAB strains identified in this study could be used in developing novel fermented products bio-enriched in natural folates that could in turn be used as an alternative to fortification with the controversial synthetic chemical folic acid.


2020 ◽  
Vol 3 (2) ◽  
pp. 134
Author(s):  
Aikaterini Georgala

Greek and Cyprus Trahanas are the most popular fermented milk-cereal products of Greece and Cyprus, and are produced during summer from fresh ewes’, goats’ milk or a mixture of them. Broken wheat is then added to the fermented milk and heated to cook the mixture and then a thick paste is left to cool and cut into small pieces and left to dry (sun or oven drying). In Greek trahanas, fermentation of the lactic acid bacteria Streptococcus lactis, Streptococcus diacetylactis, Leuconostoc cremoris, Lactobacillus lactis, Lactobacillus casei, Lactobacillus bulgaricus and Lactobacillus acidophilus plays the major acid- and aroma -producing roles. A great biodiversity of microorganisms was observed during Cyprus trahanas fermentation. Lactic acid bacteria (LAB) were the predominant group, followed by yeasts. Lactococcus, Lactobacillus, and yeast species contribute greatly to its fermentation. Turkish Tarhana is the dry form of yoghurt-cereal mixture that is produced by mixing cereal flour, yoghurt, baker’s yeast (Saccharomyces cerevisiae) and cooked vegetables, salt and spices followed by fermentation for one to seven days. The fermented slurry is then air-dried and used in soup making. LAB species found in Tarhana fermentation vary depending on the raw materials, fermentation time and techniques used for its production and play an important role in lactic acid and aromatic compounds formation. Lactococcuslactis spp. lactis, Leuconostoc mesenteroides, Lactobacillus acidophilus, Enterococcus durans, Pediococcus spp., Lactobacillus delbrueckii ssp. lactis and Lactobacillus paracasei bacteria played a role during the fermentation of Tarhana dough. Yeasts were mainly represented by S. cerevisiae.


2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Hamid Reza Samadlouie ◽  
Shahrokh Gharanjik ◽  
Zohreh Beygom Tabatabaie

New strains of lactic acid bacteria (LAB) were isolated from different traditional dairy products. Six new strains named Lactobacillus delbrueckii strain A01, Lactobacillus delbrueckii subsp. bulgaricus strain D01, Lactobacillus delbrueckii subsp. bulgaricus strain E01, Lactococcus lactis strain G01, Lactobacillus delbrueckii strain C01, and Lactobacillus delbrueckii subsp. bulgaricus strain F01 were identified using 16S rDNA sequencing, morphological and biochemical traits. All strains have been registered in the National Center for Biotechnology Information (NCBI) with accession numbers MN611241.1, MN611300.1, MN611301.1, MN611303.1, MN611241.1, and MN611299.1, respectively. Having found ε-Poly-L-Lysine (ε-PL) in all strains isolated, Lactobacillus delbrueckii strain A01 was identified as an active producer of ε-Poly-L-Lysine (ε-PL). The one-factor-at-a-time method and central composite design were applied to optimize ε-Poly-L-Lysine (ε-PL). A predicted 200 ppm of ε-PL was obtained in the medium containing the lowest level of glucose, 25 g/l, and yeast extract, 6 g/l.


2002 ◽  
Vol 48 (2) ◽  
pp. 105-112 ◽  
Author(s):  
M Andrea Azcárate-Peril ◽  
Raúl R Raya

The first report of the complete nucleotide sequence of a cryptic plasmid from Lactobacillus delbrueckii subsp. bulgaricus (Lactobacillus bulgaricus) is presented. The plasmid pLBB1 consists of 6127 bp with a GC content of 44.8%. No ssDNA was detected by hybridization experiments, which is consistent with the notion that pLBB1 does not replicate by a rolling circle mechanism. A putative replication region of pLBB1 was cloned and found to be functional in Lactobacillus johnsonii and Lactococcus lactis. Plasmid pLBB1 showed significant DNA sequence identity with plasmid pLL1212 from Lactobacillus delbrueckii subsp. lactis (Lactobacillus lactis) CRL1212 (GenBank accession No. AF109691). Four open reading frames (ORFs) larger than 100 amino acids were identified. ORFA shared similarity with a putative primase–helicase system, and ORFB and ORFC exhibited limited identity with a mobilization protein and a transposase, respectively. Curing experiments did not allowed us to assign a function to the ORFs.Key words: Lactobacillus, cryptic plasmid, sequence analysis.


2002 ◽  
Vol 57 (9-10) ◽  
pp. 805-810 ◽  
Author(s):  
Ginka I. Frengova ◽  
Emilina D. Simova ◽  
Dora M. Beshkova ◽  
Zhelyasko I. Simov

A Lactobacillus delbrueckii subsp. bulgaricus HP1 strain with high exopolysaccharide activity was selected from among 40 strains of lactic acid bacteria, isolated from kefir grains. By associating the Lactobacillus delbrueckii subsp. bulgaricus HP1 strain with Streptococcus thermophilus T15, Lactococcus lactis subsp. lactis C15, Lactobacillus helveticus MP12. and Sacharomyces cerevisiae A13, a kefir starter was formed. The associated cultivation of the lactobacteria and yeast had a positive effect on the exopolysaccharide activity of Lactobacillus delbrueckii subsp. bulgaricus HP1. The maximum exopolysaccharide concentration of the starter culture exceeded the one by the Lactobacillus delbrueckii subsp. bulgaricus HP1 monoculture by approximately 1.7 times, and the time needed to reach the maximum concentration (824.3 mg exopolysacharides/l) was shortened by 6 h. The monomer composition of the exopolysaccharides from the kefir starter culture was represented by glucose and galactose in a 1.0:0.94 ratio, which proves that the polymer synthesized is kefiran.


2020 ◽  
Vol 2020 ◽  
pp. 1-9 ◽  
Author(s):  
Eun Yeong Jang ◽  
Yejin Ahn ◽  
Hyung Joo Suh ◽  
Ki-Bae Hong ◽  
Kyungae Jo

Constipation is a chronic disease caused by infrequent, inadequate, and difficult bowel movements. The present study aimed to evaluate the potential laxative effect of maltooligosaccharide (MOS) on loperamide-induced constipation in a rat model. In vitro experiments were conducted to evaluate the effect of MOS on the growth of lactic acid bacteria. Moreover, to examine the effect of MOS administration on Sprague-Dawley (SD) rats with loperamide-induced constipation, the drinking water for the rats was supplemented with 10% or 15% of MOS for 14 days, and, thereafter, the improvement in constipation was assessed. For this, the rats were divided into five groups: normal (Nor), loperamide-induced constipated (Con), positive control (15% of dual-oligosaccharide (DuO-15)), 10% MOS treated (MOS-10), and 15% MOS-treated (MOS-15). In an in vitro test, MOS treatment promoted the growth of lactic acid bacteria except Lactobacillus bulgaricus. Treatment with higher MOS dose relieved constipation in rats by improving the fecal pellet and water content. Furthermore, in the high MOS dose group, the cecal short-chain fatty acid levels significantly increased compared to those in the control group (P<0.001). MOS treatment also improved the mucosal thickness as well as mucin secretion and increased the area of intestinal Cajal cells compared to that in the control group (P<0.001). These findings suggest that MOS relieves constipation and has beneficial effect on the gastrointestinal tract, and, therefore, it can be used as an ingredient in functional foods for treating constipation or improving intestinal health.


TABLE 3 Major Commercial Fermentation Conditions for Cereal Foods Fermentation conditions Bread Beer Whiskey Soy sauce Miso Main starters Baker's yeast Brewer's yeast Distillery yeast Molds Molds (Saccharomyces (Saccharomyces (Saccharomyces (Aspergillus spp.) (Aspergillus spp.) cerevisiae) cerevisiae) cerevisiae) Saccharomyces rouxii Lactic acid bacteria Lactobacillus delbrueckii Cereals Milled wheat Barley (malted) Corn Soybeans (defatted) Rice Milled rye Sorghum Rye (malted or not) Wheat Barley Minor: Minor: Barley (malted) Minor: Soybeans Barley (malted) Corn Wheat Barley flour Wheat (malted) Rice Wheat Other ingredients Water Water Water Water Salt Salt Hops Salt Hot pepper Sugar Adjuncts Fat (corn syrup, sugar Emulsifiers or starch) Dough strengtheners Preservatives Enzymes Fermentation 1-6h2-10 days 2-3 days (Koji: 3 days at 30°C) (Koji: 2 days at 30°C) conditions 20-42°C 3-24°C 32-35°C 3-12 months 2 days to 1 year Aging: Aging: 15-30°C 30-50°C 3 days-1 month 2-3 years or more 0-13°C 21-30°C baker's yeast is probably the most common of these microorganisms that may be a problem are bacteria (usual-starters; it is commercially produced in liquid, paste (com-ly spore-forming or lactic acid bacteria, especially in some pressed), or dry form. Recently, commercial lactic acid yeast fermentations), wild yeasts, and molds. bacteria starters have been introduced for cereal fermenta-Several spore-forming bacteria (e.g., Bacillus spp.) may tions, but this application is less frequent than their regular produce amylases and degrade hydrated starchy materials. use in dairy or meat fermentations. A close control of the In bread, heat-tolerant spores of Bacillus subtilis (formerly performance of commercial starters is important, since it Bacillus mesentericus) survive the baking process; after a has a major effect on the final products. few days in bread, they produce a spoilage called ropiness, characterized by yellow spots on crumb, putrid pineapple aroma, and stringiness when breaking a piece of bread. The spores of these species, when contaminating flour, may Considering the diversity of the microbial flora that may cause a major problem in bakeries since they are highly re-be present in cereals to be fermented, undesirable microor-sistant in the environment and difficult to eliminate. How-ganisms are likely to be part of this flora and may produce ever, these bacterial infections have become rare in recent problems in the main fermentation process with subse-years, presumably due to improved sanitation. In beer, un-quent adverse effects on the final product. Nowadays these desirable microbial contamination is exhibited by viscosity, problems are lessened by good sanitary practices. Sources appearance, as well as aroma and flavor problems. of these organisms may be the cereals themselves, soil, as Microbial pathogens are usually not a problem for fer-well as any particular ingredient, surface contamination, mented cereals because of the inhibition brought about by and unsanitary handling. acids and ethanol generated by fermenting organisms. A Table 4 summarizes microbial problems likely to occur large proportion of fermented cereals are also eaten shortly during major cereal fermentations. In general, undesirable after complete cooking. However, the biggest problem


2017 ◽  
Vol 17 (1) ◽  
pp. 5
Author(s):  
Agus Safari ◽  
Sarah Fahma Ghina ◽  
Sadiah Djajasoepena ◽  
O. Suprijana ' ◽  
Ida Indrawati ◽  
...  

Mixed lactic acid bacteria culture is commonly used in yogurt production. In the present study, two lactic acid bacteria (Lactobacillus bulgaricus and Streptococcus thermophillus) was used as starter culture. Calcium carbonate was added to the starter culture to increase the quality of mixed starter culture of L. bulgaricus and S. thermophillus with ratio of 4:1. The present study was directed to investigate the chemical composition of mixed starter culture with and without calcium carbonat addition. Furthermore, the effect of each starter culture on yogurt product chemical composition was also examined. The pH, lactose, soluble protein and acid content was determined as chemical composition parameters. For starter culture without calcium carbonate addition, the yogurt has pH, lactose, soluble protein and acid content of 4.18–4.39, 4.18–4.39% w/v, 2.88–4.36% w/v and 0.82–0.99% w/v, respectively. While for starter culture with calcium carbonate addition, the yogurt product has pH, lactose, soluble protein and acid content of 4.26–4.37, 1.47–1.75% b/v, 3.42–4.95% w/v and 0.86–1.11% w/v, respectively. Addition of 0.05% w/v calcium carbonate to mixed starter culture gave effect on lactose consumption, where it still can convert lactose to lactic acid up to 45 days of storage. Furthermore, the yogurt product made with starter culture with calcium carbonate addition has higher soluble protein content compared to yogurt made with starter culture without calcium carbonate addition


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