Preliminary Studies Of Kelp Exogenous

Epiphytic bacteria were isolated from sporophytic thallus collected from Qingdao and Dalian or gametophytic filaments stored in our lab of Laminaria japonica (Phaeophyceae). Identification was done using both traditional physiological and biochemical way and molecular method. Phylogeny tree was established based on 16S rRNA gene sequence analyses, and some sequences of epiphytic strains from both sporophyte and gametophyte were different from all the sequences already exit and could be the new species. The result showed that Pseudoalteromonas was dominant in the two sporophytes samples colleted from Qingdao and Dalian. These Pseudoalteromonas strains could not be separated by their origins and there were some very closed related strains within the two samples. This indicated that the composition of epiphytic bacteria on Laminaria was related to interaction of bacteria and their hosts. These special epiphytic strains may play essential effect on the growth of Laminaria. These epiphytic bacterial strains were screened for enzymatic and antibiotic bioactivity. Several prospective strains having antibiotic or amylase or gelatinase or lipase activity were found. One plant toxin, 1-Acetyl-beta-carboline, was isolated from culture broth of a marine bacterial Alcaligenes sp. isolate LS2 and the structure was determined by detailed interpretation of mass, 1D and 2D NMR spectra. This is the first time to isolate 1-Acetyl-beta-carboline from gram-negative bacteria in the world.In order to test the effect of epiphytic bacteria on morphogenesis of Laminaria japonica development, sterilized male and female gametophytes were treated with antibiotics together with osmotic changing. These gametophytes were hybridized and the development of sporophytes were observed and recorded. Sterilized gametophytes were recorded using fluorescent staining under epifluorescent microscope but the sporophyte younglings underwent a procedure from abnormal to normal morphology together with the blooming of epiphytic bacterial which were passivated by the antibiotics temperately. An orange colored colony was found surrounding the gametophytes on agar plate for more than 10 days' incubation and this strain was identified as same as the Cytophage isolates GE04. The fluorescent staining proved that GE04 could attach to the surface of gametophytes and have the active interaction with its host.