Team:Baltimore BioCrew/Contribution
Contribution
Overview
Inspired by the 2018 Duesseldorf iGEM team who created a Cyanobacteria Q and A, we have decided to provide facts about the Lactobacillus rhamnosus bacteria for the benefit of future iGEM teams. Many teams use Lactobacillus strains, but not a lot use the rhamnosus strain, so this information should be beneficial for teams that want to use this strain that is sold over-the-counter. We also characterized this strain for our math modeling project, and that data and growth curves in LB media are available here.
We thought it’d be best to answer some of the most significant questions that may be asked about our chosen bacteria through a Q&A so that answers to these questions are easily accessible in the future.
Question & Answer
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Where can Lactobacillus be sourced from (labs, facilities, companies, etc.)? I
Lactobacillus can be sourced from ATCC and Creative Enzymes, as well as a variety of over-the-counter probiotic brands such as Culturelle Culturelle.
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Culture Conditions (media, feeding frequency, type of plate, temp, etc.) I
Lactobacillus grow in a low oxygen level environment with a pH level between 5.5 and 6.2 and an optimal temperature of 40.5 degrees C. MRS Agar/Broth is the ideal media for L. Rhamnosus, and either broth or plates may be used. The doubling time is approximately 20 minutes.
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Can Lactobacillus be transformed (ie can plasmids be added in, and what protocols work for this)? I
Lactobacillus can be transformed via electroporation using this protocol.
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What plasmids are designed for Lactobacillus? I
Lactobacillus can use endogenous plasmids because their ability to replicate in the original hosts make it easy and efficient to create genetic tools for gene cloning and expression. A specific plasmid is pSIP403, which is for expression of a gene of interest in L. plantarum and L. sakei.
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Are Biobricks compatible with Lactobacillus? What Biobrick parts have been designed for or expressed in Lactobacillus? I
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Biobricks designed for Lactobacillus I
Team Biobrick Description iGEM07_Edinburgh BBa_I742123 Multi-host vector pTG262 converted to BioBrick vector iGEM07_Edinburgh BBa_I742103 pTG262 Plasmid (Gram negative to Gram positive shuttle vector) iGEM13_Uppsala BBa_K1033206 Lactobacillus shuttle vector pSBLbC iGEM13_Uppsala BBa_K1033207 Shuttle vector pSBLbE for E. coli and Lactobacillus IGEM13_Bordeaux BBa_K114822 Plasmid with the p-hydroxyphenylbut-3-ene-2-one synthase gene IGEM13_Bordeaux BBa_K114823 Plasmid with the p-hydroxyphenylbut-3-ene-2-one reductase gene
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What strains of Lactobacillus are used as probiotics? What benefits do people claim that these probiotics have? I
Strains of Lactobacillus used as probiotics include Lactobacillus acidophilus and rhamnosus, both of which are commonly used as probiotics with many benefits to promoting gut health. Lactobacillus acidophilus has been known to increase amounts of healthy bacteria in the gut, including lactobacilli and Bifidobacteria. Similarly, Lactobacillus plays an important role in production of lactic acid, preventing harmful bacteria from colonizing the intestines.
A separate study examined how the combination of L. acidophilus and a prebiotic affected human gut health. It found that the combined supplement increased the amounts of lactobacilli and Bifidobacteria in the intestines, as well as branched-chain fatty acids, which are an important part of a healthy gut.
L. rhamnosus can prevent Candida albicans, a type of harmful bacteria, from colonizing your intestinal walls. L. rhamnosus not only prevents bad bacteria from colonizing but also encourages the growth of beneficial bacteria, such as Bacteroides, Clostridia, and bifidobacteria.
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What are some commercially available examples of Lactobacillus probiotics? I
Lactobacillus can be commercially found within supplement pills, such as Culturelle , containing probiotics to promote health and aid in digestion. Similarly, there are many products containing Lactobacillus, such as yogurts, sauerkraut, kombucha, sourdough bread, and kimchi, that contain naturally occurring probiotics. Examples of popular yogurt brands that incorporate strains of Lactobacillus acidophilus include Chobani and Yoplait, containing probiotics which serve to increase iron levels in the blood, boost the immune system, and fight inflammation in the body.
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What evidence is there that Lactobacillus is effective as a probiotic? I
Lactobacillus has been proven effective as a probiotic through various studies conducted on improving eczema. Between participants ages 6 months and 9 years, probiotic treatment with single strains or mixtures that included Lactobacillus strains significantly reduced the risk of atopic dermatitis, a common form of eczema, from 34.7% in the control group to 28.5% in the probiotic group. In another study conducted, lactobacillus has also been associated with neutralizing toxins and other toxic compounds, promoting immunological function.
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Where are lactobacillus derived from? I
Lactobacillus acidophilus was originally isolated from the human gastrointestinal tract, and is characterized as Gram-positive, rod shaped, non spore-forming bacteria. The bacteria is also characterized by being able to produce lactic acid from the fermentation of carbohydrates. However, lactobacilli in general can be found within natural environments such as the soil, as well as decaying plant material.