Isolation and Identification of the Pathogen Causing Skin Ulcer Disease in Cynoglossus semilaevis Günther and Its Sensitivity to Chinese Herbal Medicine

In this study, the pathogen causing skin ulcer disease in Cynoglossus semilaevis Gunther was isolated for morphological observation, physiological and bio- chemical identification. According to the result, the isolated pathogen was identified as Vibrio harveyi. The results of recurrent infection of C. semilaevis Gonther showed that the pathogen was strongly pathogenic to C. semilaevis Gunther. In or- der to explore the pathogenesis, outer membrane protein （OMP） gene of C. semi- laevis Gunther was detected by PCR. The results showed that all the three repre- sentative strains harbored OMP gene. According to the results of sensitivity test of the pathogen to Chinese herbal medicine, Galla Chinensis, Fructus Mume, Fructus Hippophae and Lignum Sappan exerted strong antibacterial effects against V. harveyr, Pericarpium Granati exhibited slight antibacterial effect against V. harveyi; Pericarpium Citri Reticulatae, Rhizoma Acori GramineL Herba Houttuyniae, Herba Portulacae, Herba Andrographis, Eucalyptus globulus Labill. and Herba Menthae Heplocalycis had little effect on V. harveyi. Galla Chinensis, Fructus Mume, Fructus Hippophae and Lignum Sappan were prepared into three prescriptions, among which prescription 1 （Galla Chinensis ＋ Fructus Mume） exhibited the strongest antibacterial effect.

Antibacterial Activity of Extracts from Zostera marina Against Pathogens of Apostichopus japonicus Skin Ulceration Disease

The purpose of this study was to investigate the antibacterial activity of extracts from Zostera marina against the pathogens of Apostichopus japonicus skin ulceration disease.When 95% ethanol (v/v) solvent was used to extract Zostera marina at 50℃,aqueous extract (ZA) showed obvious bacteriostatic effects on the tested bacterial strains (inhibition halo diameters between 8.23 mm and 13.62 mm),whereas the ethyl acetate extract (ZE) was almost inactive.The minimal inhibitory concentration (MIC) of ZA against four pathogens were homogeneous at 12.8 g L-1.ZA components were analyzed by thin layer chromatography (TLC) assay and six fractions were obtained.In another study,the six fractions showed inhibitory effects against the tested bacteria while their functions seemed to counteract the ZA activity.

16S rRNA Gene Phylogenesis of Culturable Predominant Bacteria from Diseased Apostichopus japonicus(Holothuroidea,Echinodermata)

Cultured Apostichopus japonicus in China suffers from a kind of skin ulceration disease that has caused severe economic loss in recent years. The disease,pathogens of which are supposed to be bacteria by most researchers,is highly infectious and can often cause all individuals in the same culture pool to die in a very short time. The 16S rRNA gene phylogenesis of the culturable bacteria from the lesions of diseased individuals was conducted to study the biodiversity of the bacterial communities in the lesions and to identify probable pathogen(s) associated with this kind of disease. S. japonica samples were selected from a hatchery located in the eastern part of Qingdao,China. Bacterial universal primers GM5F and DS907R were used to amplify the 16S rRNA gene of bacteria colonies,and touchdown PCR was performed to amplify the target sequences. The results suggest that γ-proteobacteria(Alteromonadales and Vibrionales) of CFB group,many strains of which have been also determined as pathogens in other marine species,are the predominant bacterial genera of the diseased Apostichopus japonicus individuals.