Evaluation of salinomycin isolated from Streptomyces albus JSY-2 against the ciliate, Ichthyophthirius multifiliis.

The present study was undertaken to investigate the antiparasitic activity of extracellular products of Streptomyces albus. Bioactivity-guided isolation of chloroform extracts affording a compound showing potent activity. The structure of the compound was elucidated as salinomycin (SAL) by EI-MS, 1H NMR and 13C NMR. In vitro test showed that SAL has potent anti-parasitic efficacy against theronts of Ichthyophthirius multifiliis with 10 min, 1, 2, 3 and 4 h (effective concentration) EC50 (95% confidence intervals) of 2.12 (2.22-2.02), 1.93 (1.98-1.88), 1.42 (1.47-1.37), 1.35 (1.41-1.31) and 1.11 (1.21-1.01) mg L-1. In vitro antiparasitic assays revealed that SAL could be 100% effective against I. multifiliis encysted tomonts at a concentration of 8.0 mg L-1. In vivo test demonstrated that the number of I. multifiliis trophonts on Erythroculter ilishaeformis treated with SAL was markedly lower than that of control group at 10 days after exposed to theronts (P < 0.05). In the control group, 80% mortality was observed owing to heavy I. multifiliis infection at 10 days. On the other hand, only 30.0% mortality was recorded in the group treated with 8.0 mg L-1 SAL. The median lethal dose (LD50) of SAL for E. ilishaeformis was 32.9 mg L-1.

[Macrozoobenthos community structure and its indicative significance in water quality bioassessment of Fenshuijiang Reservoir, Zhejiang Province of East China].

A monthly investigation was conducted on the macrozoobenthos at 7 stations of Fenshuijiang Reservoir in Zhejiang Province of East China from November 2008 to October 2009. A total of 37 taxa were collected, most of which belonged to Oligocheata and Chironomidae. Limnodrilus hoffmeisteri was dominant in spring, summer and autumn, and Chironomus gr. plumosus was prevailing in winter. The collector-gatherer was the predominant group in species number, density and biomass. The mean annual density and biomass of the community were (488.0 +/- 48.8) ind X m(-2) and (1.86 +/- 0.49) g X m(-2), respectively. There were no significant differences in the macrozoobenthic density among the stations and in the macrozoobenthic biomass among the stations and among the seasons, but the macrozoobenthic density had a significant seasonal variation, with the sequence of spring > summer > winter > autumn. Water temperature and water depth were the main factors affecting the spatial distribution of the macrozoobenthos. Shannon index and Goodnight-Whitley index were not suitable for the assessment, whereas the Wright index, Carlander index, Pielou index and trophic level index showed that this reservoir was slightly polluted.