Lactobacillus - Science topic
A genus of gram-positive, microaerophilic, rod-shaped bacteria occurring widely in nature. Its species are also part of the many normal flora of the mouth, intestinal tract, and vagina of many mammals, including humans. Pathogenicity from this genus is rare.
Questions related to Lactobacillus
I am doing research on probiotics and prebiotics, now looking some specific strains like Bifidobactirum, Lactobacillus and in this regarding need some information regarding isolation and molecular characterization of these species
MRS broth containing ingredients like ammonium citrate inhibit many microorganisms including gram negative bacteria, if i collect supernatant from mrs broth lactobacillus culture and use the supernatant against test strain by well diffusion method how can i know whether the zone of inhibition is given by supernatant or mrs broth itself against test strain?
Taxonomic names for lactobacillus species have been updated (lactobacillus plantarum to Lactiplantibacillus, lactobacillus brevis to Levilactobacillus brevis, etc).
When we talk about these species, is it right to continue to refer to them as lactobacillus species?
Or is it preferable to call them lactic acid bacteria or family Lactobacillaceae?
Thank you for your advices
HT-29 colon cancer cells were incubated with cell-free supernatants of Lactobacillus spp. for 48 & 72 hours.
When observed under the microscope, control cells showed growth over 48 to 72h and appeared confluent. Moreover, purple formazan crystal formation was greater in 72h control compared to 48h control (see attached pictures) confirming cell proliferation and active cell metabolism.
However, when 72h control cell crystals were dissolved in isopropanol, their absorbance was lower than expected (OD 2.57 vs OD 3.0) and almost in the level of 48h control cells (OD 2.25). Moreover, the low concentration Lactobacillus-treated cells were actually those who yielded the expected OD of 72h control cells (OD 3.4).
Reproducibility was quite good, so maybe we are looking for systematic rather than random errors.
Any ideas? Please feel free to suggest.
I know we can use McConkeys Agar for gram -ve bacteria, however due to some reasons the only agar available at the moment is TSA. I am working on Acinetobacter and there were times when I have noticed the growth of lactobacillus. That is why I am eager to know if we can modify TSA in such a way that it supports the growth of gram -ve bacteria only? I also have MHA and BHI available, can we make them selective as well?
I need some help on the identification of unexpected bands.
Extraction of plasmidic DNA from pBluescriptII (lane 1,6) and extraction of genomic DNA from Lactobacillus plantarum (lane 4,5).
pBluescriptII ( ~ 3kb) and Lactobacillus ( ~3300 kb)
Regarding plasmidic DNA (lane 1,6) there are two bands. First band could correspond to the supercoiled and the band below could correspond to the circular, single stranded ?
Regarding genomic DNA, there are 2 bands between 1500bp and1000bp that I can´t understand why they appear. Don´t know if working with Lactobacillus is normal to see these 2 bands.
I want to culture the different lactic acid bacteria that are present in fermented vegetables, i saw that MRS medium is mostly selective for lactobacillus, but there are many more types of bacteria present in the fermented vegetables. Would it be possible to grow the whole array by simply removing sodium acetate? How big is the risk of contamination from other sources?
I am trying to transfer a Lactobacillus strain with a plasmid I've prepared for recombinant protein expression. I've been able to show that the plasmid has been taken up by the bacteria but there's no protein expression, and looking back I realised that I got the gene codon optimised for E. coli by mistake.
Can anyone tell me or point me towards a resource where I can check in theory if Lactobacillus codon usage is different for E. coli and if this might be an explanation for my lack of protein expression?
I want to check before committing resources to getting the plasmid remade. Thanks!
Can I use anti fungal agents in MRS agar for culturing Lactobacillus? Whether these anti fungal agents wll affect the growth or gene expression of the bacteria or not?
I'm trying to isolate the bacteria from probiotic pharmaceutical capsules. The growth conditions i'm currently using are: 37 ºC, pH 6.5, anaerobic atmosphere.
When using MRS broth, I put the bacterial cultures in agitation at 120 rpm.
The specific problem is that I cannot re-culture my strain in a fresh agar plate taking a sample another plate that previously grew well on. Even if i want to try culturing a sample in broth, it doesn't grow.
I read some articles that argument that pH and temperature are important factor.
Some references of another lactobacilli report propertly growth when incubating at 37ºC & pH 7.4.
Does anyone has any recommendations?
looking for the relation of biogenic amine synthesis with lactobacillus bacteria. which lactobacillus strain is responsible for synthesizing biogenic amines, and how the metabolism process is performed.
If the probiotic products contain bifidobacterium and lactobacillus spp.then it is difficult to cultivate in aerobic environment as we have tried it.But when we provide anaerobic environment then also the growth is not comming. We are isolating these culture but they are unable for separate isolation of both the microbes. So can you suggest any methods for doing these research.
hello, i want to isolate lactobacillus from feta cheese, can someone recommend a certain method ? I already isolated but there was no growth at all !!
- 1g of feta cheese was mixed by vortex with 9ml of distilled water , 1ml of the serial dilutions was added into MRS agar and spread by the loop .. incubated anaerobically for 72 under 37 C
I am new to metabolomics and have never used GC-MS. I am analyzing the common compounds (nothing specific) present in the cell-free supernatant of Lactobacillus, and I do not know if I can submit my sample without further processing. Thank you for any help!
Hello, i'm isolating lactobacillus from commercial dairy products on MRS agar, i used serial dilutions but not satisfied with the final results.. it seems that the colonies are small as you can see in the picture .. is it normal ! how can i make it grow better?
- I used 9 ml of distilled water to prepare the dilutions with 1g of commercial yogurt samples
- I covered the plates with parafilm and plastic bags to create anaerobic conditions
- Scharlau MRS agar have been used
he main metabolite of Lactobacillus was lactic acid.
In some food (poultry meat or fish) decrease of pH (lower than 5) was not accepted.
Could encapsulation be effective?
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Hello, i'm working on lactobacillus isolates from different dairy products and food samples , and focusing on the effects of bacteriocins against food-borne pathogens. How can i distinguish the action of bacteriocin from other antimicrobial compounds like organic acids and hydrogen peroxide ? can someone give the exact steps ? thank you
Bacteria are highly diverse in nature, different bacterial genera like bacillus, rhizobium, pseudomonas, azospirillum, acetobacter , lactobacillus, are if mixed all together to make a consortia, how can we make same concentration of 108 cell per ml, throughout, so that the final product have same cells of each genera?
I want to concentrate 25-30 KD protein from supernatant of lactobacillus coagulance. which method is safe? please tell me a good method with high efficiency.
Hello, i want to isolate Lactobacillus from different food samples and measure their antimicrobial effects on pathogens .. the problem is that i can't find any MRS agar that is not expired ... can i use the expired ? does it affect the pH? or should i use another medium ? i need your suggestions . thank you
I am working on L. crispatus & L. acidophilus. After freeze-drying, I resuscitated the bacteria into MRD broth & left them in incubator at 37oC for 1 hour. After that, I performed cell viability, only to find 4% survived. Could anyone share a protocol on cell viability on freeze-dried Lactobacillus spp.? I used 10% skim milk as a cryoprotectant.
I Am trying to culture lactobacillus and Candida together. I am having difficulty because lactobacillus likes to grow anaerobically whereas candida prefers aerobic conditions. If anyone has any suggestions on how to solve this dilemma, growing them together, can you please let me know? I am using MRS and YPD media 50%:50%
I tried a method to naturally ferment coconut water as described in one of the methodologies but there seems to be a host of microflora despite culturing them on MRS media (Selective media for LAB). What can I add to the MRS media that will inhibit the growth of other microflora besides LAB?
Hello fellow researchers. I am struggling to find a good plasmid miniprep protocol for Gram-positive bacteria, specifically Lactococcus lactis. I have followed several protocols on PubMed, and I have also tried to dig through previous questions with little to no luck. One such example is the paper "Rapid Mini-Prep Isolation of High-Quality Plasmid DNA from Lactococcus and Lactobacillus spp." (O'Sullivan and Klaenhammer 1993). The problem I am having, is that I am getting chromosomal DNA in all of the preps that I attempt. I am trying to determine if my plasmid is present, and I have tried several methods such as colony PCR with no success due to negative control contamination due to our building's air quality. Basically, I have been doing variations of lysozyme pretreatments of 20-50 mg/mL at 37 C for various times. I have followed protocols as best as I can, but I keep getting smears of DNA. My gels are done properly, so I know that is not the issue. Can anyone point me in the right direction? Or possibly provide me with a protocol that is more updated than 1993? I appreciate any and all help.
A cell free supeernatant of Lacttobacillus was prepared and stored in a refrigirator for 2-3 months to test its anticancer activity... is it still efective after this period of storing time or do I need to prepare a new one?
Is there someone who can help for the protocol and related article about using GCMS to determine the metabolite profiling in Lactobacillus plantarum which is fermented in milk?
I am looking for a replicative vector to transform Lactobacillus species. Can anybody help me?
The medium I use is a broth and the microorganisms are aspergillus and lactobacillus.
Thanks in advance!!
I'm having great success using Cell Tracker red with Lactobacillus. Cell Tracker Blue CMHC and Green CM-H2DCFDA aren't working. I'm doing some trouble-shooting but I'd appreciate any insights from people who have tried these dyes on bacteria.
I am currently working on Lactobacillus salivarius for an eventual bacteriocin production, I don't adjust the pH of the supernatant when realizing the deep well diffusion agar test. To check wether the prior inhibition effect of the supernatant is due to pH or to other inhibitors in the supernatant, I prepared a control of MRS-Broth-HCl solution at a pH of 4 that I tested against the same bacteria. At the same time and same plate, I tested again the supernatant that I have also at pH 4 , and surprisingly I got an inhibition only for the MRS-HCl and nothing with the supernatant, even though it is by pH 4 . Do you have any suggestion that may help ? Thank you very much !
This is very interesting and I'd like to give it a try!
I am new to the DGGE primer set, I am going to research on the microbiome analysis through DGGE, but I would like to ask is there any DGGE primer set fit for universal bacteria? And is there any DGGE primer set for sepcial type of bacteria (such as Lactobacillus)? Thanks. Also, I would like to ask is there any detailed ptotocol on the DGGE analysis including the reagents information? Many thanks.
I have been struggling with B12 (cyanocobalamin) Micro Assay which uses Lactobacillus Leichmannii.
I am using USP 171 as the reference method. I'm not quite understood of the procedure.
I'm not getting the results. As we are suspecting the growth of Lactobacillus is not strong as it gives high transmittance reading when I cross check with UV-Vis.
How do I stab transfer of pure culture of Lactobacillus Leichmannii, and make not fewer than 10 successive transfers of the culture in a 2- week period?
Can someone help me with this L. Leichmannii cultivation and the assay. As the referance as follows:
USP REFERANCE STANDARDS <171> Vitamin B12 Activity Assay.
Thank You in advance.
Hi everyone! I'm looking for literature for quantifying lactobacillus from the oral cavity. I've quantifying lactobacilli using qPCR and CFU, but I want to contrast the data with the literature because the results so far are intriguing. The experiments have been performed and analyzed by two different people. The data is consistent between experiments but contrary to the expected.
Therefore, I want to contrast our methods and results with the available literature or with the experience from other groups.
Thanks in advance for your kind help!
I am trying to figure out why the Lactobacillus stops growing in a fed batch process in a bioreactor , the cells stop consuming the glucose and stop doubling eventually, what could be the reason ?
I need to culture Ecoli, Enterococcus, and Lactobacillus strains in a minimal medium with reduced carbon sources in an anaerobic environment. I tried culturing with the M9 medium but the growth is very very slow. The Ecoli inoculated with 0.1OD took nearly 24hrs to reach an OD of 0.5 whereas the Lactobacillus and Enterococcus could not even reach the 0.2 OD. Could anyone suggest me a better minimal media which is appropriate for the anaerobic bacterial culturing.
Thanks in advance.
For part of my PhD project, I'm hoping to grow some lactobacillus species in the lab so that I can create standard curves for a qPCR quantification of a faecal sample. However, I have only ever grown E.coli before so I'm not confident with the lactobacillus growth conditions.
Can you please provide me with some information about growing different lactobacillus species? Preferably aerobically as it will be more difficult for me to access an anaerobic chamber...
I was thinking of ordering some cells from ATCC (https://www.lgcstandards-atcc.org/products/all/23272.aspx#generalinformation). Is it possible to use the same agar and LB broth recipe as I'd use for e.coli or does it need to be altered for lactobacilli?
Any advice would be much appreciated. (As detailed as possible).
I tried to isolate Bifidobacterium species using the BSM agar. However, molecular identification of the isolates by 16S rRNA gene sequencing resulted in 97+ to 99.6 % similarity to different Lactobacillus species. Can I take this result as it is? Is it reliable? Or could it possibly be that there was an error in the molecular identification technique somewhere? Please kindly guide me with your experiences if you have one. Thanks in advance.
I'm looking for selective culture media for quantifying (CFU on agar plates) Enterococcus and Lactobacillus -separately- from mixed polymicrobial cultures. These mixed cocultures contain several microbial species, and I'm trying to isolate and quantify -in separate plates- Enterococcus spp and Lactobacillus spp.
Thanks in advance!
Hi, I've been looking for literature regarding the production of metabolites that are produced primarily by the host and then biotransformed by Lactobacillus to antifungal compounds. Does anyone has seen something like that? Thanks!
PD. An example would be this article:
I'm doing some research in the proteins secreted by L rhamnosus and I've been trying to optimise the fermentation conditions to maximise production of these proteins. Without pH control the media pH drops pretty rapidly to around pH 3, and my research has shown that at around pH 4.5 all of the secreted proteins have precipitated. I've therefore been attempting to control the pH to prolong the fermentation times in order to increase the amount of secreted proteins. pH 5.0 and 6.0 seems to yield a similar array of secreted proteins over a 24 h fermentation, whereas pH 7.0 shows a lot more protein in the media, and a very different array of proteins to the lower pHs.
Is this something anyone else has come across, and is there a reason why most research I can find doesn't talk about fermentation of lactobacilli at pH as high as pH 7.0?
I am trying to isolate lactic acid bacteria from fermented fish using MRS agar (with 0.3% CaCO3) by direct plating and incubating at 37 °C under anaerobic conditions. After 48 hours of incubation, milky white colonies came up (as shown in picture) but with no clear zones around the colonies. In literature, lactic acid bacteria produce a clear zone around it's colonies in MRS agar supplemented with CaCO3 due to production of acid. Should I consider picking the colonies without clear zone or have I done some mistake while preparing the agar medium?
Thank you in advance.
As per the standard Guidelines for the Evaluation of Probiotics in Food (WHO/FAO) Lactobacillus and Bifidobacterium are GRAS Organisms but what if the study needs to done with other genera like Staphylococcus or Enterococcus as probiotic. What are the safety assessment studies needs to be done for non GRAS cultures?
I'm going to perform a solid state fermentation and I need to inoculate it using Lactobacillus.
Thanks in advance!
Does it have, anything to do with their fermentation status?
I know that in several species of LAB, the terminal d-alanine residue is replaced by d-lactate or d-serine in the muramylpentapeptide, preventing vancomycin binding and therefore becoming resistant to this antibiotic, but why L. acidophillus is still sensitive to vanc.?
Hi, I am trying to extract DNA from lactobacillus colonies, I have made an overnight culture and have NucleoBond HMW isolation kit. I also have to sequence its full-length 16S rRNA. Can someone please describe steps from isolation until sequence achievement? Since I am a first timer. I am very confused.
What would be the acceptable CV% and SD for copy number results between stool samples in qPCR (same group)? I am evaluating different bacteria (E.coli, Lactobacillus, etc.) using the absolute quantification method. My CVs after calculating the number of copies was very high (some over 25%). I read that for gene expression this would be acceptable, for bacterial quantification would it also be? If you can give me a reference, I appreciate it. I know that there also doesn't seem to be a consensus on the expression of the final result, I saw articles expressing the result in number of copies, log10, number of copies / ng of feces, among others
I want a protocol for Lactobacillus Acidophilus Isolation
I am using specific probes for detecting and quantify bacteria with FACS, however in spite, it is supposed to work (Previous studies and In silico analysis of the probes), I only get high fluorescence but unspecific hybridization.
I have tried different variables to increase the specificity:
-Formamide concentration in the Hyb buffer (20mM Tris 7.0, 0.1% SDS, 0.9M NaCl)
-Increase wash steps and change pH (SSC20x)
-Change hybridization temperatures (From 48° to 70°) 4 hrs with agitation
-Reduce the concentration of the probes
Universal GCT GCC TCC CGT AGG AG- 6FAM
Bifidobacteria GAT AGG ACG CGA CCC CAT-CY5
Lactobacillus ACA TGG AGT TCC ACT-CY3
In silico analysis: Mathfish
All the bacteria are pure cultures washed in PBS, fixed in Alcohol 50% or formaldehyde 3.7% and the permeability of the bacteria have been tested with PI
However, none of these changes had a significant change. Is there anything else that I could try?
Thank you in advance
I am currently staining and fixing a range of bacteria for a glycobiologist.
I am fixing the bacteria in 4% PFA and then washing with PBS. After fixing Lactobacillus spp. in PFA, it wont pellet. I have centrifuged it at 10000g for 5 minutes.
Does anyone perhaps know why this is? What fixation method should I use instead.
One review (
My team was trying to profile bacterial phylum composition in food sample using qPCR. We used 16s universal primers and primers specific for certain phylum such as Firmicutes and Proteobacteria. By using this approach we expected to be able to calculate how much the ratio of a certain phylum compared to the total number of bacteria. We used E. coli as standard for amplification with universal primers and other pure culture for the other phylum-specific primers (e.g. Lactobacillus for firmicutes). When the result came out, we found that in some samples, the copy number using phylum specific primer was higher than amplification of the same sample with universal primer. Logically this should not be possible since that implies we have more firmicutes for example than the total number of bacteria in that sample. What would be the explanation behind this? Is qPCR technically feasible for the analysis that we were planning to do?
What do you recommend cheaper culture media instead of MRS media for Lactobacillus bacteria ssp. plantarum?
detection of nitrite in raw milk and cheese and possible capability of lactobacillus to eliminated it.
Currently I am working with Lactobacillus genera, but I don´t know if Lactobacillus casei and Lactobacillus paracasei are considered the same specie...I had a scientific paper about differentiation of these two specie using diferents primers but this publication is from 1999 but I have to find something some recent to contrast this information....anyone can help me with this??
I am looking to set up a routine method for monitoring the cell density of lactobacillus bacteria. I have seen different wavelengths in spectrophotometer measurements to monitor cell density (i.e. 540-640nm) in different papers.
Has anyone done experiments/found research papers demonstrating a light absorption wavelength that tightly correlates with cell density in lactobacillus?
Like a title, I have a questions about compatibility between a gram positive and a gram negative bacterial genes.
If I design a plasmid based on gram positive bacteria like Lactobacillus strains, then can the plasmid be worked in E. coli after transformation?
If yes, are there differences in structures or functions??
Also, would you tell me any paper that can help to understand this concept?
Research enigma! Cloning in lactobacillus! After transformation I got complete white colonies but after sub culturing the same , It is starting to see red colonies.No idea from where I got those red colonies(my plasmid had RFP but I digested it with R.E and gel confirmation also done). If my restrictions digestion is not proper then I should have red colonies after transformation and sub culturing. perplexed !
What i understood is is,
Lactobacillus sporogenes is a heat stable, gastric acid resistant strain of probiotic bacteria. It was the original name of the Bacillus Coagulans probiotic strain. and its no more belongs to probiotic family.
I did a count of Lactobacillus in a probiotic powder but I have found problems with the dilutions and count.
I prepared a sotck solution of the powder in physiologic water (9gr/L NaCl) and did decimal dilutions from 10^-3 to 10^-10. Three consecutive decimal dilutions were inoculated in MRS agar (suplemented with cycloheximide and bromocresol purple) in triplicate and incubated at 30-35 ºC under anaerobiosis (5% CO2) for 3 days.
After the period of incubation I did the count of the colonies and I observed the typical white colonies of Lactobacillus. However, there was no concordance among the dilutions. For example, I counted 100 CFU in 10^-8 plates, 87 in 10^-9 and 45 in 10^-10 plates. I have repeated the analysis 2-3 times more with the same result. It is impossible to see the reduction of 1 grade among decimal dilution.
First, I though it could be a problem related to contamination because, sometimes I could see hundreds of tiny colonies in the plates apart of the Lactobacillus white colonies. Maybe, the Lactabacillus population is too high in the Lactobacillus and it is saturated so the count are quite similar among dilutions?
This week I have repeated again the analysis and the dilution until 10^-20. I have spread 10^-20, 10^-19, 10^-18, 10^-16, 10^-14, 10^-12, 10^-10 and 10^-8 dilutions. This time I see the white big colonies and several of the tiny ones. Again, I do not have a diference of one order of magnitude among dilutions.
Where is the problem? What is it wrong?
All the process was carried out in a laminar flow cabinet in aseptic conditions.
We are looking at enumerating total and individual viable counts in a probiotic product containing a mixture of Lactobacillus rhamnosus, Lactobacillus casei, and 2 Bifidobacteria. Any selective media or technology to perform this? I am thinking of flow cytometry but not really sure. Any suggestion? Thanks.
I have to do a competition growth curve with two different isolates (Salmonella and Lactobacillus). What approach would you use to do this?
I thought I could grow them seperately (Salmonella in LB and Lactobacillus in MRS broth), add them both into the media I choose and take optical density readings, also, to determine if one has inhibited the other, I could then plate them onto LB agar and MRS agar and record CFU.
Does this sound right?
Thanks for your help in advance.
I would like to isolate lactobacillus sp. from a sample.
So i used a MRS agar supplemented with caco3.
However, there is enterococcus sp. in the sample.
This makes it difficult to distinguish between the two on the media.
Is there a characteristic that distinguishes lactobacillus from enterococcus?
Please give me the answer!
is Lactobacillus MRS agar used to isolate all Lactic acid bacteria? agan i need to supplement 0.3% of Calcium Carbonate to MRS agar, how can i supllemnt , before or after sterilization( autoclaving) the media?
I am using some Lactobacillus strains in my study and I want to measure the production of Lactic acid by these bacteria. I am aware of several kit (abcam, cyman, sigma) which can help me to measure the concentration of Lactic acid but I want to know, if there is any procedure to measure Lactic acid concentration without using commercial kit.
Dear folks, culture lactobacillus what is the parameter to maintain during fermentation batch size is 15L, which medium is suitable for lactobacillus and how to scale up the culture please share your knowledge .
Dear fellows, do you have an idea how to prepare soy bean cultivation media to determine growth of Lactobacillus species. I need to replicate soymilk content.Should I prepare it with raffinose/stachyosse and beta conglycinin? What commercial media do you use for the purpose?
How to obtain the good quality of DNA from Gram positive rod like Lactobacillus?
I wanted Lactobacillus acidophillus culture for my research project.I would be greatful if anyone can help me out.Iam from Bangalore
I wanted to ampily my gene of interest from lactobacillus species. I wanted to use manual isolation method. Can someone help me with the protocol. Can i use protocol used for E.coli?
I have isolated few bacteria in MRS agar (pH 6.2), Starch Casein Agar (pH 7.2) and LB agar media (pH 7.2) but I am confused how to differentiate each other. Kindly give some suggestion.
single cell protein production from Lactobacillus for Protocol i.e. Saccharide, lipids, calcium, inorganic phosphate, Magnesium.
I am trying to isolate bacterial genomic DNA from lactobacillus which is incubated +4 degree (around one week), and in a tube (inside liquid media). But I could not get a high DNA concentration from them. I dont think it is related source but I am confused. Can you help me anyone? Thanks in advance.
its about isolation lactobacillus from cheese and other dairy products.
Why lactobacilli have intrinsic resistance toward Vancomycin?
I am wondering the necessity for this evaluation in different probiotic trials. I appreciate any colleagues who could help me with this question.
i am working on lactobacillus isolates and checked its antimicrobial activity, at once they show positive results but now they didn't show any result, kindly suggest me solution for this, and also guide me about protocol of TLC for antimicrobial compounds (bacteriocin), which solvents can be use for it?
need exact modified MRS media composition for lactobacillus / at what percent can lower the amount of meat extract and peptone or any suggested minimal media composition for lactobacillus???