A method of detecting dissimilation of citrate by lactic acid bacteria usingStreptococcus lactisvar.diacetilactisNCDO 1007

1967 ◽  
Vol 34 (1) ◽  
pp. 39-45 ◽  
Author(s):  
Ellen I. Garvie
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Assay Method ◽  
Streptococcus Lactis ◽  
The Relationship

SummaryIn suitable media the relationship between the citrate content and the acetoin formed by the growth ofStreptococcus lactisvar.diacetilactisNCDO 1007 is linear. An assay method for citrate is described which is based on this relationship. It has been used to assay the residual citrate in cultures of lactic acid bacteria and, therefore, to assess the ability of these bacteria to dissimilate citrate. Some suitable media for the test are described.

618. Host-phage relationship of cheese starter organisms: I. Interaction of phage races with a strain of Streptococcus lactis and its lysogenic and resistant derivatives

1956 ◽  
Vol 23 (1) ◽  
pp. 120-125 ◽  
Author(s):  
J. Czulak ◽  
Jill Naylor
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Bacterial Strain ◽  
Acquired Resistance ◽  
Secondary Growth ◽  
The Other ◽  
Physiological Changes ◽  
Streptococcus Lactis ◽  
Lysogenic Culture ◽  
Relationship Of

A lysogenic culture, prepared in the laboratory from a strain of Streptococcus lactis, was used as a cheese starter in commercial factories. It was attacked in turn by two other unrelated phage races. The lysogenic condition, which involved slight morphological and physiological changes, persisted in the subsequent forms resistant to one or both the new phage races. Acquired resistance to any one of the three phages did not protect the culture from the other two phages.In nature such interactions between phage races and lactic acid bacteria must be constantly taking place, giving rise to similarly related strains.Two of the three phage races produced spreading haloes around their plaques due to a lysin released during phage action. The lysin may also interfere with the survival of secondary growth after attack by these phage races. Production of this type of lysin is thus a property of the phage race and not of the bacterial strain.

Behavior of Listeria monocytogenes in Skim Milk during Fermentation with Mesophilic Lactic Starter Cultures

1988 ◽  
Vol 51 (8) ◽  
pp. 600-606 ◽  
Author(s):  
MICHELLE M. SCHAACK ◽  
ELMER H. MARTH
Keyword(s):  
Lactic Acid ◽  
Listeria Monocytogenes ◽  
Lactic Acid Bacteria ◽  
Skim Milk ◽  
Starter Cultures ◽  
Plate Count ◽  
Inoculum Level ◽  
Plate Count Agar ◽  
Streptococcus Lactis ◽  
Streptococcus Cremoris

The ability of Listeria monocytogenes to grow and compete with mesophilic lactic acid bacteria was examined. Autoclaved skim milk was inoculated with 103 cells of L. monocytogenes (strain V7 or Ohio)/ml, and with 5.0, 1.0, 0.5 or 0.1% of a milk culture of either Streptococcus cremoris or Streptococcus lactis. Inoculated milks were fermented for 15 h at 21 or 30°C, followed by refrigeration at 4°C. Samples were plated on McBride Listeria Agar to enumerate L. monocytogenes and on either APT Agar or plate count agar to enumerate lactic acid bacteria. L. monocytogenes survived in all fermentations, and commonly also grew to some extent. Incubation at 30°C with 5% S. lactis as inoculum appeared to be the most inhibitory combination for strain V7, causing 100% inhibition in growth based on maximum population attained. S. cremoris at the 5.0% and 0.1% inoculum levels, was slightly less inhibitory to L. monocytogenes at 37°C, but it was slightly more inhibitory to L. monocytogenes at the 1.0% inoculum level than was S. lactis. In general, S. lactis reduced the pH of fermented milks more than did S. cremoris. The population of L. monocytogenes began to decrease before 15 h in only one test combination, which was use of a 5.0% inoculum of S. cremoris and 30°C incubation. In most instances, growth of the pathogen appeared to be completely inhibited when the pH dropped below 4.75.

Detection by Warburg manometry of compounds stimulatory to lactic acid bacteria

1982 ◽  
Vol 49 (3) ◽  
pp. 479-486 ◽  
Author(s):  
Leslie E. Webb
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Scenedesmus Obliquus ◽  
Test Organism ◽  
Rapid Test ◽  
Lag Phase ◽  
Streptococcus Lactis ◽  
Manometric Method ◽  
Strain Dependent ◽  
Stimulation Of

SUMMARYThe effect of aqueous algal extract, yeast extract casein peptone and meat peptone on acid production by 4 strains of lactic acid bacteria was tested manometrically using a milk–bicarbonate medium. A strain-dependent stimulation of the bacteria was detected after 4 h incubation. After fractionation of an aqueous extract of the green algaScenedesmus obliquuson a Sephadex G25 column, 2 fractions with stimulatory activity were found usingStreptococcus lactisas the test organism. One of the peaks of activity, confined to shortening of the lag phase, was due to hypoxanthine which, however, had only a slight stimulatory effect in conventional milk souring tests. The manometric method provides a sensitive and rapid test for detecting compounds with biological activity in µg amounts, but it should be accompanied by milk souring tests for interpretation of the type of stimulation involved.

scholarly journals A sugar utilization phenotype contributes to the formation of genetic exchange communities in lactic acid bacteria

2021 ◽  
Author(s):  
Shinkuro Takenaka ◽  
Takeshi Kawashima ◽  
Masanori Arita
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Genetic Exchange ◽  
Ecological Niches ◽  
Fermented Foods ◽  
Genomic Evolution ◽  
Phenotype Data ◽  
High Utilization ◽  
The Relationship ◽  
Bacterial Groups

Abstract In prokaryotes, a major contributor to genomic evolution is the exchange of genes via horizontal gene transfer (HGT). Areas with a high density of HGT networks are defined as genetic exchange communities (GECs). Although some phenotypes associated with specific ecological niches are linked to GECs, little is known about the phenotypic influences on HGT in bacterial groups within a taxonomic family. Thanks to the published genome sequences and phenotype data of Lactic Acid Bacteria (LAB), it is now possible to obtain more detailed information about the phenotypes that affect GECs. Here, we have investigated the relationship between HGT and internal and external environmental factors for 178 strains from 24 genera in the Lactobacillaceae family. We found a significant correlation between strains with high utilization of sugars and HGT bias. The result suggests that the phenotype of the utilization of a variety of sugars is key to the construction of GECs in this family. This feature is consistent with the fact that the Lactobacillaceae family contributes to the production of a wide variety of fermented foods by sharing niches such as those in vegetables, dairy products, and brewing-related environments. This result provides the first evidence that phenotypes associated with ecological niches contribute to form GECs in the LAB family.

Inhibition of Enteropathogenic Escherichia coli by Homofermentative Lactic Acid Bacteria in Skimmilk

1977 ◽  
Vol 40 (11) ◽  
pp. 754-759 ◽  
Author(s):  
J. F. FRANK ◽  
E. H. MARTH
Keyword(s):  
Escherichia Coli ◽  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Starter Culture ◽  
Enteropathogenic Escherichia Coli ◽  
Plate Method ◽  
E Coli ◽  
Streptococcus Lactis ◽  
Streptococcus Cremoris ◽  
Plating Method

Inhibition of enteropathogenic Escherichia coli in skimmilk at 21 and 32 C by 0.25 and 2.0% of added Streptococcus lactis, Streptococcus cremoris, or a mixed strain starter culture was studied. After 15 h of fermentation, fermented milks were refrigerated at 7 C and then were tested periodically for survival of E. coli. Three methods for enumeration of E. coli during these fermentations were compared. They included trypticase soy agar (TSA) pour plates, violet red bile agar (VRB) pour plates, and TSA surface plating with a VRB overlay. Lactic cultures had similar inhibitory properties at 32 C, but there were differences at 21 C, with S. lactis being least inhibitory and the mixed strain culture most inhibitory. The VRB pour plate method gave poorest recovery of E. coli when fermentation was at 32 C and when fermented milks were refrigerated. The TSA surface plating method apparently allowed for recovery of injured E. coli cells and gave results similar to the TSA pour plate method.

SURVIVAL OF SALMONELLA TYPHIMURIUM IN REFRIGERATED CULTURED MILKS1

1972 ◽  
Vol 35 (8) ◽  
pp. 489-495 ◽  
Author(s):  
H. s. Park ◽  
E. H. Marth
Keyword(s):  
Lactic Acid ◽  
Citric Acid ◽  
Lactic Acid Bacteria ◽  
Salmonella Typhimurium ◽  
Streptococcus Thermophilus ◽  
Lactobacillus Helveticus ◽  
Lactobacillus Bulgaricus ◽  
Refrigerated Storage ◽  
Streptococcus Lactis ◽  
Pure Cultures

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.

Behavior of Listeria monocytogenes in the Presence of Lactic Acid Bacteria in an Agitated Medium with Internal pH Control

1991 ◽  
Vol 54 (3) ◽  
pp. 183-188 ◽  
Author(s):  
JANE M. WENZEL ◽  
ELMER H. MARTH
Keyword(s):  
Lactic Acid ◽  
Statistical Analysis ◽  
Listeria Monocytogenes ◽  
Lactic Acid Bacteria ◽  
Lactococcus Lactis ◽  
Ph Control ◽  
Lactococcus Lactis Subsp ◽  
Streptococcus Lactis ◽  
Streptococcus Cremoris ◽  
Internal Ph

An agitated medium with internal pH control (IPCM-2) was inoculated to contain Listeria monocytogenes (strain V7, Scott A or California) at ca. 103 CFU/ml and Streptococcus cremoris (Lactococcus lactis subsp. cremoris) or Streptococcus lactis (Lactococcus lactis subsp. lactis) at 0.25 or 1.0% The inoculated medium was incubated with shaking in a waterbath at 30°C for 30 h. L. monocytogenes and lactic acid bacteria were enumerated and pH was determined at appropriate intervals. The area on a figure between curves for the control and treatment and designated as the area of inhibition (AI) was calculated and used to quantify inhibition of each strain of L. monocytogenes for a particular set of conditions in IPCM-2. Statistical analysis of AI values calculated from data obtained at 6, 24, and 30 h of incubation revealed no significant (p < 0.05) difference in inhibition among the three strains of L. monocytogenes for each type of lactic streptococcus present. Streptococcus cremoris was significantly (0.01 < p < 0.05) more inhibitory to all three strains of L. monocytogenes than was S. lactis at 24 and 30 h of incubation. IPCM-2 is considered ready for use at a pH of 5.4 or less, which was reached between 12 and 15 h of incubation in samples containing 0.25 or 1.0% S. cremoris. Populations of L. monocytogenes in such samples were ca. 104 to 106 CFU/ml regardless of strain of Listeria or percentage of S. cremoris added as inoculum. In samples initially containing 0.25 or 1.0% S. lactis, pH 5.4 was not reached until after 18–24 h of incubation. At this point all three strains of L. monocytogenes had grown to ca. 105 CFU/ml regardless of percentage of S. lactis added as inoculum. Despite the inhibition seen, substantial numbers of the pathogen were present when the medium was ready for use.

scholarly journals Profiling of Potential Antibacterial Compounds of Lactic Acid Bacteria against Extremely Drug Resistant (XDR) Acinetobacter baumannii

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1727
Author(s):  
Phui-Chyng Yap ◽  
Noorfazlin Ayuhan ◽  
Jia Jie Woon ◽  
Cindy Shuan Ju Teh ◽  
Vannajan Sanghiran Lee ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Acinetobacter Baumannii ◽  
Docking Study ◽  
Binding Mode ◽  
Gas Chromatography Mass Spectrometry ◽  
Assay Method ◽  
Drug Resistant ◽  
Molecular Docking Study

A total of 20 of isolates of lactic acid bacteria (LAB) were selected and screened for antagonistic activity against clinical strains of 30 clinical isolates of extremely drug-resistant (XDR) Acinetobacter baumannii using the well diffusion assay method. Results showed that 50% of the highly LAB strains possessed inhibitory activity against (up to 66%) of the XDR A. baumannii strains tested. The supernatant of the twenty LAB strains was subjected to gas chromatography mass spectrometry (GCMS) revealed that the common compound found in the active isolates against XDR A. baumannii was 3-Isobutyl-2,3,6,7,8,8a-hexahydropyrrolo[1,2-a]pyrazine-1,4-dione, a known potential diketopiperazine group. The molecular docking study against potential antibacterial targets with selected ligands was performed to predict the binding mode of interactions, which is responsible for antibacterial activity. The docking analysis of the potent compounds supported the potential antibacterial activity exhibiting high inhibition constant and binding affinity in silico.

scholarly journals Molecular characterization of lactic acid bacteria producing edible biofilm isolated from kimchi

2020 ◽  
Vol 21 (3) ◽  
Author(s):  
FADILLA SAPALINA ◽  
Endah Retnaningrum
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
16S Rrna ◽  
16S Rrna Gene ◽  
Lactobacillus Brevis ◽  
Fermented Food ◽  
Gene Isolation ◽  
Assay Method ◽  
Rrna Gene ◽  
Production Test

Biofilm is a community of microorganisms that interrelated and covered by an extracellular polymer matrix. This biofilm can be produced by Lactic acid bacteria (LAB) which was edible for human and animal.  Therefore, it possible to be applied in the food and health industry. One source of LAB is kimchi, as fermented food from Korea and it has good benefits for health. This research aimed to obtain LAB from kimchi that can produce edible biofilms and to identify LAB producing edible biofilms based on the 16S rRNA gene. Isolation of lactic acid bacteria from kimchi cultured in MRS agar medium containing 1% CaCO3, biofilm production test with biofilm assay method and zeolite as a substrate to adherent cells. For amplification of 16S rRNA gene used primer 27F and 1492R. The isolate of KA2, KA5, KB1, and KC4 isolated from kimchi and could produce biofilms with the highest biofilm formation at 48 hours incubation time. Based on molecular identification with 16S rRNA gene sequencing, the four isolates identified as Lactobacillus brevis species.

Sign in / Sign up

Export Citation Format

Share Document