For my research work I need two types of Lactobacillus along with the normal one.
Type one - Lactobacillus sp that grows at pH 6-7, But do not grow at pH 3-4.
Type two- Lactobacillus sp that grows at higher temperature (60 oC) but growth rate is very slow at 37 oC.
Can anyone please suggest me any source for this
The question does not make much sense. First: which species? The genus Lactobacillus as >>50 species (and I frankly doubt any of them would grow at 60°C although L. helveticus may grow at 52-55°C).
Unless you plan to use mutagens and random selection, to obtain strains with a reduced temperature range you usually have to tamper with chaperonin genes. For pH is more complicated because several genes are involved in tolerance to acid. If I were you, I would first identify the strain (?) you are working with, then look at the genome of the species for targets for inactivation.
In addition to Prof. Parente comments, and without any information abut the goal of the request, I would suggest the possible isolation of high temperature tolerant lactobacilli from high temperature natural sources and then to select a subpopulation of the new strain through high temperature incubation. However the new (mutant?) isolate could be still able to grow normally at 37°C. More difficult is to find your acidity non-tolerant lactobacilli. Probably you could find other LAB strains with reduced acidity tolerance.
Thanks Prof. Parente and Prof. Baruzzi for your comments. Actually my goal is to get a Lactobacillus strain which can colonize (or stay for some time) in digestive system but it should not be able to divide in that condition. Do you think attenuated or heat killed bacteria may work for me?
so i think sir you are looking for genetically modified strains from Lactobacillus in order to be sure from their growth at such conditions
Probably you could find other LAB strains with reduced acidity tolerance.
Dear Diptiman Choudhury basend on my knowledge about gut colonization by Lactobacillus I think that the result of your research could be reached:
1 - using (or isolating) a Lactobacillus strain endowed with high adhesion properties to human gut ;
2 - growing it under condition promoting adhesion
3 - carrying out in vitro experiment to verify if it can adhere after different killing treatment (please note that many molecules involved in adhesion are sensitive to physico-chemical treatments)
4 - verify in in vivo experiments (eg. mouse) the best result from step 3 so, in addition, to understand how long it can colonise (or persist in) the gut
The immunostimolation by dead lactobacillus cells should have been already published (sorry I do not remember the paper!) so you can take advantages from that results.
However, in order to reach you goal I have some problem to understand your previous questions.
Wishing you successfull experiments
Best regards
FBaruzzi
Prof. Baruzzi, Thanks for your suggestions and wishes. I am wondering if we have any known instances where after killing (attenuation) those bacteria were able to colonize (or just occupy the intestinal lining) in human intestine due to intact cell adhesion molecules like cell surface proteins etc. I wonder whether they can stay there at that condition for some time period like for a week or so.
Dr. Shenan. I am looking for Lactobacillus strain which will colonize (occupy and stay there for some time) on intestine lining but will not grow there.
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