Lactobacillus paracasei

Lactobacillus paracasei
Lactobacillus bulgaricus, morphologically identical to Lactobacillus paracasei
Scientific classification
Domain: Bacteria
Phylum: Firmicutes
Class: Bacilli
Order: Lactobacillales
Family: Lactobacillaceae
Genus: Lactobacillus
Species: L. paracasei
Subspecies: Lactobacillus paracasei ssp. paracasei
Lactobacillus paracasei ssp. tolerans
Binomial name
Lactobacillus paracasei
Collins, Phillips & Zanoni, 1989

Lactobacillus paracasei (commonly abbreviated as L. paracasei) is a gram-positive, facultatively heterofermentative species of lactic acid bacteria that are commonly used in dairy product fermentation and probiotics. L. paracasei is a bacterium that operates by commensalism. It is commonly found in many human habitats such as our intestinal tracts and mouths as well as sewages, silages, and previously mentioned dairy products.[1] The name includes morphology, a rod-shaped (bacillus shape) bacterium with a width of 2.0 to 4.0μm and length of 0.8 to 1.0μm.

So far, thirty four different strains of L. paracasei have been isolated from a variety of environments. Sixteen of those strains have been isolated from dairy, ten from plants, and eight from human and animal gastrointestinal tracts.[2] L. paracasei is genotypically and phenotypically indistinguishable from other members of its genus such as Lactobacillus casei and Lactobacillus rhamnosus.[3] However, they are easily differentiated from each other by their fermentation profiles.[4] Its fermentative properties allows it to be used as biological food processors and supplements for diets and medical disorders, especially in the gastrointestinal tract.[5]

Although probiotics are considered safe, they may cause bacteria-host interactions and adverse health consequences. In certain cases there is a risk of bacteremia when probiotics are used.[6][7] Currently, the probiotic strain, frequency, dose and duration of the probiotic therapies are not established.[6]

Physiology

Lactobacillus paracasei is a gram-positive, facultatively heterofermentative, non-spore forming microorganism.[8] The cells of L. paracasei are typically rod shaped, with a size range of 2.0μm to 4.0μm in width, and 0.8 to 1.0μm in length.[3] The organism is nonmotile. L. Paracasei cells often have square ends, and may exist either in single form or in chains.[3]

L. paracasei grows optimally in a temperature range between 10 and 37 °C.[9] No growth takes place above 40 °C. The organism is able to survive for approximately 40 seconds in a maximum temperature of 72 °C.[3] As L. Paracasei is facultatively heterofermentative: lactic acid is produced from most strains.

L. paracasei exist as a common inhabitant of the human gastrointestinal tract as part of the normal flora.[8] Naturally fermented vegetables, milk, and meat may also contain strains of L. paracasei.[9]

Phylogeny

Lactobacillus paracasei belongs to kingdom Bacteria. L. paracasei is part of the division Firmicutes, and also belongs to the class Bacilli.[3] The order and family are Lactobacillales and Lactobacillaceae respectively.[3] The argument on the nomenclature of L. paracasei versus L. casei has been one of intense debate. Most of the species profiled as L. casei or L. paracasei have been found to be part of the same species.[2] In 1989, it was proposed that L. paracasei be designated a subspecies (paracasei) to account for the species that it shares DNA homology with.[3] It has been shown their names have been used interchangeably in scientific literature.[2] 16S RNA sequence homology has confirmed the relatedness between these species.[3]

Historically, the difference between Lactobacillus paracasei and other lactobacilli has been based on biochemical characteristics. There is an approximately 90% sequence identity between casei, paracasei, and rhamnosus.[2] However, there are some differential criteria that are commonly used to differentiate between them. These differential criteria include nutritional requirements and growth environment.[2] L. Paracasei has been found to show specific differences with other Lactobacillus spp. in that it is somewhat heat resistant, grows well in ripening cheese, and it has high proteolytic activity.[10]

L. paracasei has been found to have 34 strains.[2] These strains have been isolated from various countries around the world. Although there is a small correlation between phylogenetic relatedness and origin of isolation, currently there is not enough evidence to support direct proof of the relationship.[2]

Genomics

L. paracasei's genome contains circular DNA and varies slightly among the different strains isolated. On average, the genomes are 2.9 to 3.0 millions of base pairs (commonly abbreviated Mb). It has a GC-content between 46.2 and 46.6% and is predicted to encode about 2800 to 3100 proteins. The difference in the genomes of these strains lies in variant cell envelopes, secretory proteins, and polysaccharides. Many of the commonly coded proteins are cell-surface associated cell-wall hydrolases that protect the cell against apoptosis. These enzymes have been shown to provide cellular protection to human epithelial cells.[2]

Genetic diversity for the different L. paracasei genomes was assessed using multilocus sequence typing (MLST) and amplified fragment length polymorphism (AFLP). MLST is a technique used for classifying microbes by the use of DNA fragments from essential genes of the organism.[11] AFLP is a Polymerase Chain Reaction (PCR) tool used in DNA profiling to amplify a desired DNA fragment with the use of restriction enzymes and ligands.[12]

Clinical and research applications

Lactobacillus paracasei has been identified as a bacterium that has probiotic properties.[1] L. paracasei is a part of the normal human gut microbiota.[10][13] L. paracasei IMPC2.1 may be a chemoprophylactic in gastrointestinal cells.[14] Gastrointestinal cells are susceptible to apoptosis and cell growth from both heat-killed and viable IMPC2.1 strains.[1] L. paracasei 8700:2 has been isolated from healthy human gastrointestinal mucosa and human feces.[10] Strain 8700:2 was also found to inhibit Salmonella enterica and Heliobacter pylori, two pathogens commonly found in the gastrointestinal tract. Strain 8700:2 breaks down oligofructose and inulin, while also growing rapidly on both and producing lactic acid as the end product.[13]

L. paracasei is a constituent in the therapeutic, nutritional treatment VSL#3. This proprietary, standardized, formulation of live bacteria may be used in combination with conventional therapies to treat ulcerative colitis.[15]

Health concerns

The manipulation of the gut microbiota is complex and may cause bacteria-host interactions. Although probiotics are considered safe, when they are used by oral administration there is a risk of passage of viable bacteria from the gastrointestinal tract to the internal organs (bacterial translocation) and subsequent bacteremia, which can cause adverse health consequences.[6] Some people, such as those with immune compromise, short bowel syndrome, central venous catheters, cardiac valve disease and premature infants, may be at higher risk for adverse events.[7]

Currently, the probiotic strain, frequency, dose and duration of the probiotic therapy are not established.[6] Live bacteria might not be essential because of beneficial effects of probiotics seems to be mediated by their DNA and by secreted soluble factors, and their therapeutic effects may be obtained by systemic administration rather than oral administration.[6][16]

History

LAB (Lactic Acid Bacteria) were classified and grouped in the early 1900s after gaining scientists' attention after observing the bacteria's interactions in different foods, especially dairy products. In 1991, Martinus Beijerinck, a Dutch microbiologist, separated Lactobacillus as gram positive bacteria from the previously known LAB group.[17] L. paracasei has been recently classified as a part of the Lactobacillus casei group of probiotics.[1] However, it has no clear taxonomic position. The name L. paracasei was proposed for rejection in 1996 by Dicks, Duplessis, Dellaglio, and Lauer.[3]

References

  1. 1 2 3 4 Orlando, A.; Refolo, M. G.; Messa, C.; Amati, L.; Lavermicocca, P.; Guerra, V.; Russo, F. (October 2012). "Antiproliferative and Proapoptotic Effects of Viable or Heat-Killed IMPC2.1 and GG in HGC-27 Gastric and DLD-1 Colon Cell Lines". Nutrition and Cancer. 64 (7): 1103–1111. doi:10.1080/01635581.2012.717676.
  2. 1 2 3 4 5 6 7 8 Smokvina, Tamara; Wels, Michiel; Polka, Justyna; Chervaux, Christian; Brisse, Sylvain; Boekhorst, Jos; Vlieg, Johan E. T. van Hylckama; Siezen, Roland J.; Highlander, Sarah K. (19 July 2013). "Lactobacillus paracasei Comparative Genomics: Towards Species Pan-Genome Definition and Exploitation of Diversity". PLoS ONE. 8 (7): e68731. doi:10.1371/journal.pone.0068731.
  3. 1 2 3 4 5 6 7 8 9 COLLINS, M. D.; PHILLIPS, B. A.; ZANONI, P. (1 April 1989). "Deoxyribonucleic Acid Homology Studies of Lactobacillus casei, Lactobacillus paracasei sp. nov., subsp. paracasei and subsp. tolerans, and Lactobacillus rhamnosus sp. nov., comb. nov.". International Journal of Systematic Bacteriology. 39 (2): 105–108. doi:10.1099/00207713-39-2-105.
  4. ↑ Ward, L. J. H.; Timmins, M. J. (August 1999). "Differentiation of Lactobacillus casei, Lactobacillus paracasei and Lactobacillus rhamnosus by polymerase chain reaction". Letters in Applied Microbiology. 29 (2): 90–92. doi:10.1046/j.1365-2672.1999.00586.x.
  5. ↑ Felten, A; Barreau, C; Bizet, C; Lagrange, PH; Philippon, A (Mar 1999). "Lactobacillus species identification, H2O2 production, and antibiotic resistance and correlation with human clinical status.". Journal of clinical microbiology. 37 (3): 729–33. PMID 9986841.
  6. 1 2 3 4 5 Durchschein F, Petritsch W, Hammer HF (2016). "Diet therapy for inflammatory bowel diseases: The established and the new.". World J Gastroenterol (Review). 22 (7): 2179–94. doi:10.3748/wjg.v22.i7.2179. PMC 4734995Freely accessible. PMID 26900283.
  7. 1 2 Doron S, Snydman DR (2015). "Risk and safety of probiotics.". Clin Infect Dis (Review). 60 Suppl 2: S129–34. doi:10.1093/cid/civ085. PMC 4490230Freely accessible. PMID 25922398.
  8. 1 2 HESSLE; HANSON,; WOLD, (May 1999). "Lactobacilli from human gastrointestinal mucosa are strong stimulators of IL-12 production". Clinical and Experimental Immunology. 116 (2): 276–282. doi:10.1046/j.1365-2249.1999.00885.x.
  9. 1 2 Rogan, WJ; Gladen, BC; Hung, KL; Koong, SL; Shih, LY; Taylor, JS; Wu, YC; Yang, D; Ragan, NB; Hsu, CC (Jul 15, 1988). "Congenital poisoning by polychlorinated biphenyls and their contaminants in Taiwan.". Science. 241 (4863): 334–6. doi:10.1126/science.3133768. PMID 3133768.
  10. 1 2 3 Molin, G.; Jeppsson, B.; Johansson, M.-L.; Ahrné, S.; Nobaek, S.; Ståhl, M.; Bengmark, S. (March 1993). "Numerical taxonomy of Lactobacillus spp. associated with healthy and diseased mucosa of the human intestines". Journal of Applied Bacteriology. 74 (3): 314–323. doi:10.1111/j.1365-2672.1993.tb03031.x. PMID 8468264.
  11. ↑ Maiden, Martin; Jane Bygraves; Edward Feil (January 6, 1998). "Multilocus sequence typing: A portable approach to the identification of clones within populations of pathogenic microorganisms". Proceedings of the National Academy of Sciences of the United States of America. 6. 95: 3140–3145. doi:10.1073/pnas.95.6.3140. PMC 19708Freely accessible. PMID 9501229.
  12. ↑ Kumar, Awanish; Anuradha Dube (February 2013). "Amplified fragment length polymorphism: an adept technique for genome mapping, genetic differentiation, and intraspecific variation in protozoan parasites [electronic resource].". 2. 112: 457–466. doi:10.1007/s00436-012-3238-6.
  13. 1 2 Makras, L.; Van Acker, G.; De Vuyst, L. (3 November 2005). "Lactobacillus paracasei subsp. paracasei 8700:2 Degrades Inulin-Type Fructans Exhibiting Different Degrees of Polymerization". Applied and Environmental Microbiology. 71 (11): 6531–6537. doi:10.1128/AEM.71.11.6531-6537.2005.
  14. ↑ Bernstein, Charles N; Nugent, Zoann; Blanchard, James F (15 March 2011). "5-Aminosalicylate Is Not Chemoprophylactic for Colorectal Cancer in IBD: A Population Based Study". The American Journal of Gastroenterology. 106 (4): 731–736. doi:10.1038/ajg.2011.50.
  15. ↑ Ghouri, Yezaz A; Richards, David M; Rahimi, Erik F; Krill, Joseph T; Jelinek, Katherine A; DuPont, Andrew W (9 December 2014). "Systematic review of randomized controlled trials of probiotics, prebiotics, and synbiotics in inflammatory bowel disease". Clin Exp Gastroenterol. pp. 473–487. doi:10.2147/CEG.S27530. Retrieved 17 May 2016.
  16. ↑ Dotan I, Rachmilewitz D (2005). "Probiotics in inflammatory bowel disease: possible mechanisms of action". Curr Opin Gastroenterol (Review). 21 (4): 426–30. PMID 15930982.
  17. ↑ Stiles, ME; Holzapfel, WH (Apr 29, 1997). "Lactic acid bacteria of foods and their current taxonomy.". International Journal of Food Microbiology. 36 (1): 1–29. doi:10.1016/s0168-1605(96)01233-0. PMID 9168311.
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