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Lactobacillus gasseri ATCC 33323
   
   
 

Photo: M. Dykstra, R. Barrangou, R. Sanozky-Dawes, and T. R. Klaenhammer, North Carolina State University
Lactobacilli are normal inhabitants of the gastrointestinal tract of man and animals and are widely considered to exert a number of beneficial roles including immunomodulation, interference with enteric pathogens, and maintenance of a healthy intestinal microflora. Historically, probiotic roles have been ascribed primarily to Lactobacillus acidophilus. Recent developments in molecular taxonomy have revealed six different Lactobacillus species that comprise the acidophilus group. Among these, Lactobacillus gasseri appears to represent the major homofermentative Lactobacillus species that occupies the human GI tract (Mitsuoka, 1992; Kullen et al., 2000). This L. gasseri demonstrates good survival in the GI tract (Conway et al., 1982; Pedrosa et al., 1995) and has been associated with a variety of probiotic activities and roles including reduction of fecal mutagenic enzymes (Pedrosa et al., 1995), adherence to intestinal tissues (Conway et al, 1987; Greene and Klaenhammer, 1994), stimulation of macrophages (Kirjavainen et al., 1999; Kitazawa et al., 1994; Tejada-Simon et al., 1999; Tejada-Simon and Pestka, 1999), and production of bacteriocins (Itoh et al, 1995; Sawai et al., 1998).

There are a diverse number of naturally-occurring Lactobacillus species found in the human GI tract and many are considered to exert beneficial roles there. Establishing these roles, individually and in combination, remains a significant challenge. Realization of the genome content of one major species of intestinal lactobacilli will provide key insights toward understanding their capabilities, roles, and interactions. Functional analysis of gene content and expression will be greatly accelerated and is expected to provide key insights to the survival, roles, and potential benefits of this group of commensal organisms. Relative to the other members of the acidophilus complex, there exists a significant platform of work on the L. gasseri species related to its transformability by electroporation (Luchansky et al., 1988), expression of heterologous genes (Cho et al., 2000), and the available genome sequence information for one temperate bacteriophage (Altermann et al., 1999; Raya et al., 1992). L. gasseri is substantially more amenable to DNA introduction and manipulation which has lead to the development of more genetic tools that will be useful in the functional genomic analysis of this species (Kullen and Klaenhammer, 1999; Russell and Klaenhammer, 2001).

This project and accompanying efforts of the Lactic Acid Bacteria Genomics Consortium will carry out genome sequencing of a number of Lactobacillus species, some with considerable diversity in ecological habitat (milk, meat, plants, GI tract) and roles (probiotic versus fermentation of plants, milk, wine). Comparative genomic analysis between the various Lactobacillus species that occupy the GI tract is expected to identify important regions that are necessary for survival and activity in this environment. In addition, comparative genomics of intestinal lactobacilli with other lactic acid bacteria, from distinctive environments will hopefully identify the regions that are involved in the adaptation of lactobacilli to many specialized and varied environments, including the GI tract.

Contributed by Todd R. Klaenhammer

References:

Altermann, E., Klein, J. R. & Henrich, B. (1999). Primary structure and features of the genome of the Lactobacillus gasseri temperate bacteriophage (phi) adh. Gene 236, 333-46.

Cho, J. S., Choi, Y. J. & Chung, D. K. (2000). Expression of Clostridium thermocellum endoglucanase gene in Lactobacillus gasseri and Lactobacillus johnsonii and characterization of the genetically modified probiotic lactobacilli. Curr Microbiol 40, 257-63.

Conway, P.L., Gorbach, S.L. and Goldin, B.R. (1987) Survival of lactic acid bacteria in the human stomach and adhesion to intestinal cells. J. Dairy Sci. 70: 1-12.

Greene, J. D. & Klaenhammer, T. R. (1994). Factors involved in adherence of lactobacilli to human Caco-2 cells. Appl Environ Microbiol 60, 4487-94.

Itoh, T., Fujimoto, Y., Kawai, Y., Toba, T. & Saito, T. (1995). Inhibition of food-borne pathogenic bacteria by bacteriocins from Lactobacillus gasseri. Lett Appl Microbiol 21, 137-41.

Kirjavainen, P. V., El-Nezami, H. S., Salminen, S. J., Ahokas, J. T. & Wright, P. F. (1999). The effect of orally administered viable probiotic and dairy lactobacilli on mouse lymphocyte proliferation. FEMS Immunol Med Microbiol 26, 131-5.

Kitazawa, H., Tomioka, Y., Matsumura, K., Aso, H., Mizugaki, M., Itoh, T. & Yamaguchi, T. (1994). Expression of mRNA encoding IFN alpha in macrophages stimulated with Lactobacillus gasseri. FEMS Microbiol Lett 120, 315-21.

Kullen, M.J. and Klaenhammer, T.R. (1999b). Genetic modification of intestinal lactobacilli and bifidobacteria. In Probiotics: a Critical Review. G. Tannock (ed) Horizon Scientific Press, Wymondham, U.K., pp. 65-83.

Kullen, M.J., R.B. Sanozky_Dawes, D.C. Crowell and T.R. Klaenhammer. 2000. Use of DNA sequence of variable regions of the 16SrRNA gene for rapid and accurate identification of bacteria in the Lactobacillus acidophilus complex. J. Appl. Microbiol. 89:511-518.

Luchansky, J.B., Muriana, P.M., and Klaenhammer, T.R. (1988). Application of electroporation for transfer of plasmid DNA to Lactobacillus, Lactococcus, Leuconostoc, Listeria, Pediococcus, Bacillus, Staphylococcus, Enterococcus, and Propionibacterium. Mol. Microbiol. 2:637-647.

Mitsuoka, T. (1992) The human gastrointestinal tract. In, The Lactic Acid Bacteria: Volume 1, The Lactic Acid Bacteria in Health and Disease. B.J.B. Wood (ed), pp69-114.Elsevier Science Publishers, Ltd. Essex, England.

Pedrosa, M.C., Golner, B.B., Goldin, B.R., Barakat, S., Dallal, G.E., and Russell, R.M. (1995). Survival of yogurt-containing organisms and Lactobacillus gasseriA (ADH) and their effect on bacterial enzyme activity in the gastrointestinal tract of healthy and hypocholorhydric elderly subjects. Am. J. Clin. Nutr. 61, 353-359.

Raya, R. R., Fremaux, C., De Antoni, G. L. & Klaenhammer, T. R. (1992). Site-specific integration of the temperate bacteriophage phi adh into the Lactobacillus gasseri chromosome and molecular characterization of the phage (attP) and bacterial (attB) attachment sites. J Bacteriol 174, 5584-92.

Russell, W.M. and T.R. Klaenhammer. 2001. Identification and cloning of gusA, encoding a new B-glucuronidase from Lactobacillus gasseri ADH. Appl. Environ. Microbiol. 67: 1253-1267.

Tejada-Simon, M. V. & Pestka, J. J. (1999). Proinflammatory cytokine and nitric oxide induction in murine macrophages by cell wall and cytoplasmic extracts of lactic acid bacteria. J Food Prot 62, 1435-44.