title: Arginine- and Polyamine-Induced Lactic Acid Resistance in Neisseria gonorrhoeae.
abstract: Microbe-derived lactic acid protects women from pathogens in their genital tract. The purpose of this study was to determine lactic acid susceptibility of Neisseria gonorrhoeae, and identify potential acid resistance mechanisms present in this pathogen. Tested in vitro, lactic acid killed all 10 gonococcal strains analyzed in a low pH-dependent manner. Full inactivation occurred at pH 4.5. At low pH, lactic acid treatment resulted in the entry of the DNA-binding fluorochrome propidium iodide into the microbial cells, suggesting that hydrogen ions from lactic acid compromise the integrity of the bacterial cell wall/membrane. Most likely, hydrogen ions also inactivate intracellular proteins since arginine rendered significant protection against lactic acid presumably through action of the gonococcal arginine decarboxylase, an enzyme located in the bacterial cytoplasm. Surprisingly, arginine also lessened lactic acid-mediated cell wall/membrane disruption. This effect is probably mediated by agmatine, a triamine product of arginine decarboxylase, since agmatine demonstrated a stronger protective effect on GC than arginine at equal molar concentration. In addition to agmatine, diamines cadaverine and putrescine, which are generated by bacterial vaginosis-associated microbes, also induced significant resistance to lactic acid-mediated GC killing and cell wall/membrane disruption. These findings suggest that the arginine-rich semen protects gonococci through both neutralization-dependent and independent mechanisms, whereas polyamine-induced acid resistance contributes to the increased risk of gonorrhea in women with bacterial vaginosis.
authors.affiliation: Department of Pharmacology, Rutgers University Robert Wood Johnson Medical School, Piscataway, New Jersey, United States of America.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Gong
authors.affiliation: Department of Pharmacology, Rutgers University Robert Wood Johnson Medical School, Piscataway, New Jersey, United States of America.
authors.forename: M Matt
authors.initials: MM
authors.lastname: Tang
authors.affiliation: Department of Pharmacology, Rutgers University Robert Wood Johnson Medical School, Piscataway, New Jersey, United States of America.|Department of Urology, Hunan University of Traditional Chinese Medicine-affiliated Ningxiang People's Hospital, Changsha, Hunan, China.
authors.forename: Xueliang
authors.initials: X
authors.lastname: Wu
authors.affiliation: Department of Obstetrics, Gynecology and Reproductive Sciences, and Women's Health Institute, Rutgers University, New Brunswick, New Jersey, United States of America.
authors.forename: Nancy
authors.initials: N
authors.lastname: Phillips
authors.affiliation: Public Health and Environmental Laboratories, New Jersey Department of Health, Ewing, New Jersey, United States of America.|Department of Pathology and Laboratory Medicine, Rutgers University Robert Wood Johnson Medical School, Piscataway, New Jersey, United States of America.
authors.forename: Dariusz
authors.initials: D
authors.lastname: Galkowski
authors.affiliation: Center for Immunochemistry, Veterans Affairs Medical Center, San Francisco, California, United States of America.|Department of Laboratory Medicine, University of California, San Francisco, California 94143, United States of America.
authors.forename: Gary A
authors.initials: GA
authors.lastname: Jarvis
authors.affiliation: Department of Pharmacology, Rutgers University Robert Wood Johnson Medical School, Piscataway, New Jersey, United States of America.
authors.forename: Huizhou
authors.initials: H
authors.lastname: Fan
mesh_terms: D001120:Arginine / Q000502:physiology*; D015317:Biogenic Polyamines / Q000502:physiology*; D006863:Hydrogen-Ion Concentration; D019344:Lactic Acid / Q000378:metabolism*; D009344:Neisseria gonorrhoeae / Q000472:pathogenicity*; D011419:Propidium / Q000378:metabolism
chemical_list: D015317:Biogenic Polyamines; D019344:Lactic Acid; D011419:Propidium; D001120:Arginine