Improved Medium for Lactic Streptococci and Their Bacteriophages Export

@article{citeulike:2404553, abstract = {Incorporation of 1.9\% β-disodium glycerophosphate (GP) into a complex medium resulted in improved growth by lactic streptococci at 30 C. The medium, called M17, contained: Phytone peptone, 5.0 g; polypeptone, 5.0 g; yeast extract, 2.5 g; beef extract, 5.0 g; lactose, 5.0 g; ascorbic acid, 0.5 g; GP, 19.0 g; 1.0 M MgSO4·7H2O, 1.0 ml; and glass-distilled water, 1,000 ml. Based on absorbance readings and total counts, all strains of Streptococcus cremoris, S. diacetilactis, and S. lactis grew better in M17 medium than in a similar medium lacking GP or in lactic broth. Enhanced growth was probably due to the increased buffering capacity of the medium, since pH values below 5.70 were not reached after 24 h of growth at 30 C by S. lactis or S. cremoris strains. The medium also proved useful for isolation of bacterial mutants lacking the ability to ferment lactose; such mutants formed minute colonies on M17 agar plates, whereas wild-type cells formed colonies 3 to 4 mm in diameter. Incorporation of sterile GP into skim milk at 1.9\% final concentration resulted in enhanced acid-producing activity by lactic streptococci when cells were inoculated from GP milk into skim milk not containing GP. M17 medium also proved superior to other media in demonstrating and distinguishing between lactic streptococcal bacteriophages. Plaques larger than 6 mm in diameter developed with some phage-host combinations, and turbid plaques, indicative of lysogeny, were also easily demonstrated for some systems.}, author = {Terzaghi, B. E. and Sandine, W. E.}, citeulike-article-id = {2404553}, citeulike-linkout-0 = {http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=187084}, journal = {Applied Microbiology}, keywords = {bacteria, bacteriophages, lactic, medium, protocol, streptococci}, month = {June}, number = {6}, pages = {807--813}, posted-at = {2008-02-20 20:25:50}, priority = {2}, title = {Improved Medium for Lactic Streptococci and Their Bacteriophages}, url = {http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=187084}, volume = {29}, year = {1975} }

TY - JOUR ID - citeulike:2404553 L3 - citeulike-article-id:2404553 N2 - Incorporation of 1.9% β-disodium glycerophosphate (GP) into a complex medium resulted in improved growth by lactic streptococci at 30 C. The medium, called M17, contained: Phytone peptone, 5.0 g; polypeptone, 5.0 g; yeast extract, 2.5 g; beef extract, 5.0 g; lactose, 5.0 g; ascorbic acid, 0.5 g; GP, 19.0 g; 1.0 M MgSO4·7H2O, 1.0 ml; and glass-distilled water, 1,000 ml. Based on absorbance readings and total counts, all strains of Streptococcus cremoris, S. diacetilactis, and S. lactis grew better in M17 medium than in a similar medium lacking GP or in lactic broth. Enhanced growth was probably due to the increased buffering capacity of the medium, since pH values below 5.70 were not reached after 24 h of growth at 30 C by S. lactis or S. cremoris strains. The medium also proved useful for isolation of bacterial mutants lacking the ability to ferment lactose; such mutants formed minute colonies on M17 agar plates, whereas wild-type cells formed colonies 3 to 4 mm in diameter. Incorporation of sterile GP into skim milk at 1.9% final concentration resulted in enhanced acid-producing activity by lactic streptococci when cells were inoculated from GP milk into skim milk not containing GP. M17 medium also proved superior to other media in demonstrating and distinguishing between lactic streptococcal bacteriophages. Plaques larger than 6 mm in diameter developed with some phage-host combinations, and turbid plaques, indicative of lysogeny, were also easily demonstrated for some systems. IS - 6 JF - Applied Microbiology EP - 813 TI - Improved Medium for Lactic Streptococci and Their Bacteriophages VL - 29 SP - 807 KW - bacteria KW - bacteriophages KW - lactic KW - medium KW - protocol KW - streptococci AU - Terzaghi, BE AU - Sandine, WE PY - 1975/06// UR - http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=187084 ER -