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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.

Morphological studies of Sicuophora (Syn. Wichtermania) multigranularis Xiao et al., 2002, from the rectum of the frog, Quasipaa spinosa, performed using silver impregnation and scanning electron microscopy, confirmed the following newly recognized features: (1) only one apical suture on the right surface; (2) two naked regions at the posterior end of both the left and the right side of the body. Phylogenetic analysis based on the SSU-rRNA gene showed that S. multigranularis is a sister to a clade comprising all other Clevelandellida, strongly supporting the validity of the genus Sicuophora. This is also the first molecular data obtained for the genus Sicuophora. Because of the lack of molecular data, it will be necessary to obtain more genetic data from the family Sicuophoridae to discuss the question of the taxonomic status of the genus Sicuophora.

Cepedea longa Bezzenberger, 1904, collected from Fejervarya limnocharis (Amphibia, Anura, Ranidae) from Honghu Lake, Hubei Province, China in May–July 2016, is described at both light and transmission electron microscope levels. This is the first electron microscopic study of this species. Cepedea longa possesses a developed fibrillar skeletal system, composed of longitudinal fibrillar bands and transversal fibrils as well as numerous thin microfibrils dispersed in the endoplasm, which may play an important role in morphogenesis and offer some resilience to deformations of the cell. Longitudinal microfibrils are polarizing elements of kineties, bordering the somatic kineties on the left side and possibly responsible for kinetosome alignment. Two types of vesicles exist in the somatic cortex: globular endocytotic vesicles and flattened exocytotic vesicles. As to the nuclei of C. longa, a thick microfibrillar layer was observed to attach to the cytoplasmic face of the nuclear envelope. This fact suggests no necessary connection between the presence of this microfibrillar layer and the number of nuclei. In addition, some unknown tightly-packed microtubular structures in the nucleoplasm were observed for the first time in opalinids; neither their nature nor physiological significance is known. A detailed list of all reported Cepedea species is included.

The Opalinida comprise ciliated protists that live as intestinal endoparasites in poikilothermic vertebrates. They are classified as one group of colourless Stramenopiles, the Opalinata, along with Proteromonadida (Proteromonas and Karotomorpha). The validity of certain opalinid genera is questionable, and their genetic relationships remain unclear. In this study, we conducted complete ribosomal DNA gene sequencing of nine opalinid species (belonging to Opalina , Protoopalina , Zelleriella , and Cepedea) from China. We compared the primary sequences, secondary structures, and characteristics of short tandem repeats within the expansion segments of the sequences. Additionally, a TimeTree analysis was performed to estimate divergence times. Our findings suggest that opalinids diverged from proteromonads ~250–220 Mya, with Protoopalina being the ancient genus. There is no genetic evidence supporting the differentiation of Cepedea and Bezzenbergeria as distinct genera, and they have been synonymized: Opalina (= Cepedea) and Protoopalina (= Bezzenbergeria); new combinations of species names are listed. Opalinid rDNA sequences exhibit greater length compared with other groups owing to A-T insertions within the expansion segments. These insertions consist of short tandem repeats and appear to be associated with speciation events that led to genus differentiation. [ABSTRACT FROM AUTHOR]

Lipids are an essential component of living beings and an important group of nutrients. As the gut microbiota plays important roles in the intestinal absorption and extraintestinal metabolism of dietary lipids, the current review addresses the recent progress regarding the interactions between the gut microbiota and lipid metabolism in aquatic animals, with a focus on fish. We discuss in detail how dietary lipid sources and content affect the composition of the gut microbiome and the mechanism by which the gut microbiota affects the lipid metabolism of the host. This interaction is largely mediated via microbial lipases, short‐chain fatty acids and the gut‐liver axis. The latter refers to the metabolism of biliary salts and acids, the regulation of their synthesis by gut microbes and their impact on the lipid metabolism. Finally, we briefly discuss how probiotic supplementation modulates the host's microbiome, and how probiotics have a beneficial effect on health and welfare of farmed aquatic animals. Although the influence of intestinal microbiota on lipid metabolism has been explored before, further research is needed to profoundly investigate the molecular mechanisms by which microbial metabolites (SCFAs and bile acids) induce lipid metabolism. [ABSTRACT FROM AUTHOR]

The quality of welding is directly related to the performance and life of the welding structure. The nondestructive testing technology is mainly used for welding defect defection, while the X-ray testing technology can directly and reliably reflect the shape, location and size of defects. For X-ray images, manual inspection is used at present, and it is easily caused by subjective factors, such as professional level, which may lead to low accuracy. This paper focuses on establishing an end-to-end automatic detection model of X-ray welding defects to improve the accuracy and efficiency of detection based on a deep learning algorithm. Considering the feature information of welding defects, this paper improves on the basis of Faster R-CNN and uses the deep residual network Res2Net to enhance the original backbone network to improve the feature extraction ability. And the weighted feature fusion module is studied, which combines the high-level semantic information and the low-level high-resolution edge detail information to predict the feature map of each layer respectively, to improve the detection performance, especially for small targets. The experimental data show that this method can effectively improve the accuracy and efficiency of welding defect detection. [ABSTRACT FROM AUTHOR]