No abstract

Bacterial communities in eggs and larvae of grass carp were analysed. During the early-developmental stages, grass carp harboured five bacterial phyla, i.e. Proteobacteria, Bacteroidetes, Verrucomicrobia, Planctomycetes and Firmicutes. However, the composition of bacterial communities varied among the different developmental stages. In eggs, the bacterial communities were dominated by Proteobacteria, while in larvae the dominant bacterial community was Bacterioidetes. With the exception of a large proportion (>50%) of uncultured bacteria, Sphingobacterium (14.75%) and Acinetobacter (13.11%) were the most abundant groups in eggs at the fertilization stage (FS). However, Aermonas was the most abundant group, ranging from 40.54% to 61.76% in eggs at the cleavage (CS), blastula (BS), organ differentiation (ODS) and hatching stages (HS). In larvae after first ingestion (OW), Chitinophagaceae (79.41%) formed the predominant bacterial community. Changes in the bacterial community were further confirmed by statistical analysis, which demonstrated significant differences in the bacterial communities of eggs at FS, eggs from CS to HS and OW. However, no significant difference was found in bacterial communities of eggs from CS to HS. Furthermore, the present study revealed that bacteria related to Chitinophagaceae persisted from CS to OW, suggesting that these bacteria form part of the autochthonous microbiota of the fish.

Balantidium grimi n. sp. is described from the rectum of the frog Quasipaa spinosa (Amphibia, Dicroglossidae) from Lishui, Zhejiang Province, China. The new species is described by both light microscopy (LM) and scanning electron microscopy (SEM), and a molecular phylogenetic analysis is also presented. This species has unique morphological features in that the body shape is somewhat flattened and the vestibulum is “V”-shaped, occupying nearly 3/8 to 4/7 of the body length. Only one contractile vacuole, situated at the posterior body, was observed. The phylogenetic analysis based on SSU-rDNA indicates that B. grimi groups together with B. duodeni and B. entozoon. In addition, the genus Balantidium is clearly polyphyletic.