title: [Antibacterial activity of sponge associated marine bacterium Pseudoalteromonas sp. NJ6-3-1 regulated by quorum sensing].
abstract: OBJECTIVE
  We chose a sponge-associated marine-bacterium Pseudoalteromonas piscicida NJ6-3-1 to study whether its antibacterial activity were regulated by quorum sensing.
  
  
  METHODS
  We studied the relationship between the antibacterial activity and bacterial density under various growth conditions. To simulate the natural competitive environment, we monitored the antibacterial activity at low cell density when the species were co-cultured with Staphylococcus aureus.
  
  
  RESULTS
  Antibacterial activity correlated closely with cell density. Marine bacterium NJ6-3-1 started producing antibacterial compounds when cell density reached the threshold value of OD(630) = 0.4. Some signal molecules existing in the metabolites of S. aureus could induce the production of antibacterial substance by marine-bacteria NJ6-3-1 even cell density below the required threshold.
  
  
  CONCLUSIONS
  The results provide preliminary evidence to support the hypothesis that the antibacterial activity of NJ6-3-1 was regulated by the quorum sensing system of intraspecies and interspecies.
authors.affiliation: Qingdao Key Lab of Analytical Technology Development and Standardization of Chinese Medicines, First Institute of Oceanography, State Oceanic Administration, Qingdao 266061. guoxiuchun1982@163.com
authors.forename: Xiuchun
authors.initials: X
authors.lastname: Guo
authors.forename: Li
authors.initials: L
authors.lastname: Zheng
authors.forename: Zhisong
authors.initials: Z
authors.lastname: Cui
authors.forename: Ping
authors.initials: P
authors.lastname: Han
authors.forename: Li
authors.initials: L
authors.lastname: Tian
authors.forename: Xiaoru
authors.initials: X
authors.lastname: Wang
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000096:biosynthesis / Q000378:metabolism*; D002452:Cell Count; D015169:Colony Count, Microbial; D003470:Culture Media; D009792:Oceans and Seas; D011161:Porifera / Q000382:microbiology*; D031161:Pseudoalteromonas / Q000166:cytology / Q000502:physiology*; D053038:Quorum Sensing; D013211:Staphylococcus aureus / Q000166:cytology; D013696:Temperature
chemical_list: D000900:Anti-Bacterial Agents; D003470:Culture Media