Xiaoyi Pan

Antiparasitic efficacy of dihydrosanguinarine and dihydrochelerythrine from Macleaya microcarpa against Ichthyophthirius multifiliis in richadsin (Squaliobarbus curriculus).

Ichthyophthirius multifiliis is a holotrichous protozoan that invades the gills and skin surfaces of fish and can cause morbidity and high mortality in most species of freshwater fish worldwide. The present study was undertaken to investigate the antiparasitic activity of crude extracts and pure compounds from the leaves of Macleaya microcarpa. The chloroform extract showed a promising antiparasitic activity against I. multifiliis. Based on these finding, the chloroform extract was fractionated on silica gel column chromatography in a bioactivity-guided isolation affording two compounds showing potent activity. The structures of the two compounds were elucidated as dihydrosanguinarine and dihydrochelerythrine by hydrogen and carbon-13 nuclear magnetic resonance spectrum and electron ionization mass spectrometry. The in vivo tests revealed that dihydrosanguinarine and dihydrochelerythrine were effective against I. multifiliis with median effective concentration (EC(50)) values of 5.18 and 9.43 mg/l, respectively. The acute toxicities (LC(50)) of dihydrosanguinarine and dihydrochelerythrine for richadsin were 13.3 and 18.2mg/l, respectively. The overall results provided important information for the potential application of dihydrosanguinarine and dihydrochelerythrine in the therapy of serious infection caused by I. multifiliis.

Draft Genome Sequence of Aeromonas hydrophila Strain BSK-10 (Serotype O97), Isolated from Carassius carassius with Motile Aeromonad Septicemia in China

ABSTRACT We report here a draft genome sequence of Aeromonas hydrophila strain BSK-10, belonging to serotype O97, isolated from crucian carp (Carassius carassius) with motile aeromonad septicemia in Zhejiang, China. The assembly resulted in 34 scaffolds totaling approximately 4.97 Mb, with an average G+C content of 60.97% and 4,594 predicted coding genes.

Proteomic analysis of differentially expressed proteins in the two developmental stages of Ichthyophthirius multifiliis

Ichthyophthirius is a severe disease of farmed freshwater fish caused by the parasitic ciliate Ichthyophthirius multifiliis (Ich). This disease can lead to considerable economic loss, but the protein profiles in different developmental stages of the parasite remain unknown. In the present study, proteins from trophonts and theronts of Ich were identified by isobaric tags for relative and absolute quantitation (iTRAQ). A total of 2300 proteins were identified in the two developmental stages, of which 1520 proteins were differentially expressed. Among them, 84 proteins were uniquely expressed in the theronts stage, while 656 proteins were expressed only in trophonts. The differentially expressed proteins were catalogued (assorted) to various functions of Ich life cycle, including biological process, cellular component, and molecular function that occur at distinct stages. Using a 1.5-fold change in expression as a physiologically significant benchmark, a lot of differentially expressed proteins were reliably quantified by iTRAQ analysis. Two hundred forty upregulated and 57 downregulated proteins in the trophonts stage were identified as compared with theronts. The identified proteins were involved in various functions of the I. multifiliis life cycle, including binding, catalytic activity, structural molecule activity, and transporter activity. Further investigation of the transcriptional levels of periplasmic immunogenic protein, transketolase, zinc finger, isocitrate dehydrogenase, etc., from the different protein profiles using quantitative RT-PCR showed identical results to the iTRAQ analysis. This work provides an effective resource to further our understanding of Ich biology, and lays the groundwork for the identification of potential drug targets and vaccines candidates for the control of this devastating fish pathogen.

Isolation and Characterization of a Novel Dicistrovirus Associated with Moralities of the Great Freshwater Prawn, Macrobrachium rosenbergii.

The giant freshwater prawn, Macrobrachium rosenbergii, is an economically important crustacean and is farmed in many countries. Since 2009, a larval mortality syndrome of M. rosenbergii has broken out and spread widely in the main breeding area, including Zhejiang, Jiangsu, Guangxi, and Guangdong Provinces in mainland China. A novel virus, named Macrobrachium rosenbergii Taihu virus (MrTV), was isolated from the moribund larvae and was determined to be the causative agent of the M. rosenbergii larval mortality syndrome by experimental infection. Further genomic sequencing suggested that the MrTV genome is monopartite, 10,303 nt in length, and dicistronic with two non-overlapping open reading frames (ORFs) separated by an intergenic region (IGR) and flanked by untranslated regions (UTRs). Phylogenetic analysis using the full-length genomic sequence and the putative amino acid sequences of the capsid protein revealed that MrTV was more closely related to the taura syndrome virus (TSV) than to any other viruses. According to these molecular features, we proposed that MrTV is a new species in the genus Aparavirus, family Dicistroviridae. These results may shed light on controlling larval mortality syndrome in M. rosenbergii.