Lactobacillus Rhanosus – Genome Sequences and Phenotypes
This article describes the Genome sequences and phenotypes of three strains of Lactobacillus rhamnosus and explains how the diversity of L. rhamnosus strains enables us to identify their functions. It also explains the significance of genetic fingerprinting. This bacteria is one of the most common species in the human digestive tract, and its abundance is reflected in many different human and animal diseases.
Genome sequences of Lactobacillus rhamnosus strains
Genomics studies of L. rhamnosus strains have revealed that they have similar genome structures. Sequences of L. rhamnosus strains GG and LC705 have been deposited in the European Molecular Biology Laboratory (EMBL) database. The genome sequences of both strains have been annotated with gene annotations. In addition to the genome sequences, these studies also revealed that L. rhamnosus strains GG and LC705 share a common genetic makeup.
Genomics of Lactobacillus rhamnosus has been a challenge for researchers who have been interested in the species’ phylogenetics. The CDC-LR1 strain was isolated from homemade and naturally processed dairy products in Bulgaria in August 2001. Its genome was annotated in a database and predicted to contain 2,638 coding genes and 49 non-coding RNA (tRNA) genes.
Both strains GG and LC705 possess pilus genes responsible for adhesion to human mucus. Genetic analysis of the strain GG genome revealed the presence of pilin-encoding genes that are not present in the genome of other Lactobacillus species. In addition, these bacteria display phage-like characteristics in their genomes compared to other Lactobacillus species.
EPS production is a key adaptation strategy in lactobacilli, especially those that live in a harsh environment. Galactose-rich rhamnose-containing EPS molecules act as a protective shield against innate immune factors. Genome sequences of Lactobacillus rhamnosus strains GG and GR-1 have revealed similar EPS clusters in their genomes. The end-of-operate region was found to contain genes predicted to regulate the production of EPS molecules.
Although L. rhamnosus strain GG is the most studied probiotic, these new sequences reveal that L. rhamnosus strains can inhibit inflammatory cytokines and induce a gene that regulates intestinal mucin production. These strains are known to have anti-inflammatory properties in vitro and may have new biotechnological uses.
Although L. rhamnosus strains GG and L31 are closely related, they differ genetically. L. rhamnosus strains L31, L34, and L35 maintain distinctive 16S rRNA gene-based phylogeny. Despite these differences, L. rhamnosus strains are distinct from other Lactobacillus groups.
The phenotypes of Lactobacillus rhamnosus are derived from its genetic makeup and its ability to utilize different sugars. Despite their common origins, strains of L. rhamnosus display a wide range of differences in their phenotypes. The differences in growth and metabolism between the two strains are primarily related to their ability to ferment lactose.
To identify the strains of Lactobacillus rhamnosus, 109 samples were isolated from national domestic dairy products. Then, a highly active strain of Lactobacillus spp. was selected for further analysis. The strain was isolated by morphological, biochemical, and physiological properties from the samples. Finally, the strains were genotyped using Roche 454 GS FLX platforms.
The vaginal strains of L. rhamnosus exhibit the phenotype A, which lacks pili, but shows high levels of stress resistance and adaptability to various habitats. The vaginal niche has a lower diversity of bacterial organisms. Meanwhile, strains isolated from the intestines display geno-phenotype B, which has pili, bile resistance, and L-fucose utilization. Hence, this strain demonstrates an increased ability to adapt to more diverse habitats, constant changes in nutrients, and host effects.
The fatty acid content and specific surface proteins of the L. rhamnosus PEN strains were isolated. They showed different phenotypes in the synthesis of EPS and were distinguished from the other strains by the type of fatty acids they secrete. Furthermore, the bacteria were able to grow and colonize in the presence of 10A% NaCl. These findings provide a better understanding of the characteristics of the cell envelope of Lactobacillus rhamnosus strains.
In a recent study, researchers compared the growth and metabolic functions of the two strains of Lactobacillus rhamnosus and L. acidophilus in the presence of Eruca sativa. The two strains were more active than the other, and both showed increased viability and growth. They were also resistant to vancomycin. These findings also support the hypothesis that the strains differ in their phenotypes and metabolism.
The functions of Lactobacillus rhamnosus may be more than just beneficial for the intestinal tract. Studies have shown that L. rhamnosus can repair damaged intestinal tissues, including those caused by alcohol consumption. It also can denature bacterial endotoxins. In a Rush University Medical Center study, Lactobacillus rhamnosus GG significantly decreased the oxidative stress caused by alcohol consumption and lowered gut leakiness.
Another function of Lactobacillus rhamnosus was found to be its ability to suppress the inflammatory response of the body. The probiotic suppresses the production of inflammatory cytokines released by pathogenic bacteria. The probiotic also suppresses specific inflammatory pathways. In addition to limiting the inflammatory response, Lactobacillus rhamnosus is thought to be an effective immune system regulator.
The probiotic strain known as Lactobacillus rhamnosus GG was isolated from the fecal samples of a healthy adult. Although not a common probiotic, this strain has numerous benefits for the body and is the most researched. This strain has been studied around the globe and continues to benefit human health 35 years after its discovery. The probiotic strain inhibits the growth of bacterial pathogens and boosts the immune system.
Further research is needed to identify the molecular basis of these antibacterial properties. In vitro treatments of polarized IEC layers revealed differential effects on NF-kB activity and immune proliferation compared to controls. The results also showed that L. rhamnosus GR-1 has a higher frequency of GTT and a potent ODN than the other two strains tested.
The first line of defense of the mucosa is the secretory IgA response. In a 2008 study, researchers evaluated the oral immune response of individuals with birch pollen allergy. For ten weeks before the birch pollen season, these individuals were given either a placebo or Lactobacillus rhamnosus. The SIgA level was measured before, during, and after the pollen season. Researchers found that the group that took Lactobacillus rhamnosus had increased levels of SIgA.
Lactobacillus rhamnosus and L. casei are closely related. The group has long been a topic of controversy. Genotyping uses 16S rRNA gene sequences as a gold standard, but these methods are labor-intensive and require expert skills. Genome-based comparisons usually complement the standard gold method. Genetic fingerprinting is now widely used to determine the exact status of species.
The study used eight strains of L. rhamnosus, and two primers were designed to separate strains of L. rhamnosus from L. casei. The Y primers used to separate the two strains provided positive results for all but two putative L. casei strains. Genetic fingerprinting is a powerful method to determine a bacterium’s taxonomy.
The technique was initially developed to differentiate L. casei from L. paracasei. However, this method was used in later studies to determine whether the latter species is a subspecies of L. rhamnosus. Initially, this method was only used to determine the species of L. casei, which has been grouped into different subspecies. Since this bacterium is closely related to L. rhamnosus, genetic fingerprinting of this bacterium is now possible.
The method has been used to determine the strain diversity of LAB species in food products. These studies show that RAPD PCR fingerprinting is a robust and reproducible method. Reference strains and cultivated fecal bacteria produced the same amplified polymorphisms. Genetic fingerprinting is a highly sensitive technique, and it is now being used to investigate the molecular epidemiology of Lactobacillus consumption in humans.
In this study, the RAPD genotyping of strains of L. acidophilus showed high reproducibility. The RAPD fingerprints of isolates from different sources showed almost identical RAPD profiles compared to the type strain. The strain in lanes 11 to 11 matched the C65, whereas the one in lane 12 was the LMG 7955 type. Despite the similarity of the strains, the results of these tests indicate low genetic heterogeneity.
The present study obtained RAPD fingerprints of LAB strains by using a novel method that identifies persistent LAB strains based on the NCIMB 30156 feeding strain. The RAPD fingerprints of the dominant LAB strains (T+23-1a, T+28-1b, and T+23-1b) are shown in Figure 1.