title: Iron and glucose affecting growth and haemolysin production in human strains of group B streptococci.
abstract: Seven strains of group B streptococci aetiologically related to humans were investigated in order to observe the role of glucose and medium iron on their growth and haemolysin production, and the necessity of a 'carrier' molecule to ensure the stability of the haemolysin. Both growth and haemolysin production were significantly influenced by glucose and medium iron concentrations. Iron concentrations between 5 and 7 micrograms/ml and 0.5% to 1% glucose were critical. Maximum haemolysin production (detected by lysis of sheep erythrocytes) was obtained during the late exponential phase of the growth cycle, but declined, producing sigmoidal-like curves as the organism entered the stationary phase. RNA-core, serum and bovine serum albumin, stabilizers of streptolysin S had no stabilizing effect for the haemolysin of group B streptococci. However, bovine serum albumin-starch mixture (0.5% bovine serum albumin and 0.5% starch in phosphate buffered saline or brain-heart infusion) was an effective stabilizer.
authors.affiliation: Department of Microbiology/Immunology, School of Medicine, Oral Roberts University, Tulsa, Oklahoma 74137.
authors.forename: B B
authors.initials: BB
authors.lastname: Griffiths
mesh_terms: D000818:Animals; D003470:Culture Media; D004912:Erythrocytes / Q000187:drug effects; D005947:Glucose / Q000494:pharmacology*; D006460:Hemolysin Proteins / Q000096:biosynthesis*; D006801:Humans; D007501:Iron / Q000494:pharmacology*; D007700:Kinetics; D012756:Sheep; D013054:Spectrophotometry, Atomic; D013292:Streptococcus agalactiae / Q000187:drug effects* / Q000378:metabolism
chemical_list: D003470:Culture Media; D006460:Hemolysin Proteins; D007501:Iron; D005947:Glucose