The mass mortality of pond-reared scattered mirror carp, Cyprinus carpio, caused by Thelohanellus kitauei, occurred at fish farms in Sichuan Province, southwest China. Morphological and molecular analyses were supplem...The mass mortality of pond-reared scattered mirror carp, Cyprinus carpio, caused by Thelohanellus kitauei, occurred at fish farms in Sichuan Province, southwest China. Morphological and molecular analyses were supplemented with histological evaluation of infected tissues to better understand the route of infection and the pathological effects of 1＂. kitauei on the fish host. The intestine of the diseased host was full of large cysts of the myxosporean. The cysts range from 2 cm to 3.6 cm in diameter. Histopathology indicated that T. kitauei first invaded the submucosa of the host intestine and then moved into the mucosa layers with the development of their spores, finally entering into the enteric cavity of the hosts after the disruption of mucosa layers. The pyriform spores of T. kitauei were surrounded by the transparent spore sheath, measuring 25.98/μm±0.95 μm in body length, 8.72 μm±0.51μm body width, and 7.86 μm±0.26 μm in body thickness. The single polar capsule was pyriform, measuring 14.73 μm±0.92μm in length and 6.82 μm±0.45μm in width, with eight to 10 turns of filament coils winding inside. Phylogenetic analysis based on the 18S small-subunit ribosomal DNA sequences indicated that minimal genetic differences were present between T. kitauei samples from South Korea and from China. Close affinity was found between the genus Thelohanellus and Myxobolus. Additionally, two polar capsule nuclei were found at the anterior end of the single polar capsule in spores of T. kitauei stained with hematoxylin and eosin, which suggested the separation of the genus Thelohanellus from Myxobolus.展开更多
Patterns of septal insertion were analyzed in three species of Agetolites from the Upper Ordovician in Yushan County, Jiangxi Province of China. Agetolites is a peculiar coral possessing features of both tabulate （e....Patterns of septal insertion were analyzed in three species of Agetolites from the Upper Ordovician in Yushan County, Jiangxi Province of China. Agetolites is a peculiar coral possessing features of both tabulate （e.g., mural pores） and rugose corals （e.g., welldeveloped septa）. Septal patterns have long been considered to be indicative of the origin of corals, and the pattern of septal insertion in Agetolites has been known to be typical of rugosans. This study, however, reveals that the patterns in Ageto lites are rather random and cannot be an indication of its rugosan affinity. It is suggested that Agetolites probably has a closer phylogenetic relation with tabulates than with either rugosans or scleractinians. Two insertion patterns of the first six septa were detected （Types I and II）. Type I is interpreted as scleractinian pattern whereas Type II as typical pattern of rugosans. Types 1 and 2 are septal patterns of the second stage recognized in this study. Type 1 insertion occurs in six sectors located in the center of each interseptal space, suggesting scleractinian pattern of insertion. Type 2 insertion occurs in four sectors that are comparable with alar and counter sectors in rugose corals. Four patterns of the third （Types AD） and fourth stages （Types ad） of septal insertion have also been recognized in Agetolites. Type A only occurs in two adjacent sectors possibly due to the in completeness of septal development. Type B presents rugosan pattern. Types C and D resemble scleractinian pattern in most aspects. Types a, b, and c present no clear attribution to rugosan or scleractinian pattern probably due to the incompleteness of septal development whereas Type d is observable in rugose corals.展开更多
基金Supported by the earmarked fund for China Agriculture Research System(No.CARS-46-08)the National Science Foundation for Young Scientists of China(No.31301863)the Major Scientific and Technological Innovation Project of Hubei Province(No.2015ABA045)
文摘The mass mortality of pond-reared scattered mirror carp, Cyprinus carpio, caused by Thelohanellus kitauei, occurred at fish farms in Sichuan Province, southwest China. Morphological and molecular analyses were supplemented with histological evaluation of infected tissues to better understand the route of infection and the pathological effects of 1＂. kitauei on the fish host. The intestine of the diseased host was full of large cysts of the myxosporean. The cysts range from 2 cm to 3.6 cm in diameter. Histopathology indicated that T. kitauei first invaded the submucosa of the host intestine and then moved into the mucosa layers with the development of their spores, finally entering into the enteric cavity of the hosts after the disruption of mucosa layers. The pyriform spores of T. kitauei were surrounded by the transparent spore sheath, measuring 25.98/μm±0.95 μm in body length, 8.72 μm±0.51μm body width, and 7.86 μm±0.26 μm in body thickness. The single polar capsule was pyriform, measuring 14.73 μm±0.92μm in length and 6.82 μm±0.45μm in width, with eight to 10 turns of filament coils winding inside. Phylogenetic analysis based on the 18S small-subunit ribosomal DNA sequences indicated that minimal genetic differences were present between T. kitauei samples from South Korea and from China. Close affinity was found between the genus Thelohanellus and Myxobolus. Additionally, two polar capsule nuclei were found at the anterior end of the single polar capsule in spores of T. kitauei stained with hematoxylin and eosin, which suggested the separation of the genus Thelohanellus from Myxobolus.
基金supported by the Invitation and Training of Outstanding Overseas Student Researcher Program by Korea Science and Engineering Foundation(Grant No.KOSEF 211-2007-1-C00047)Korea Research Foundation funded by the Korean Government(MOEHRD)to DJL(Grant No.KRF-2006-312-C00690)
文摘Patterns of septal insertion were analyzed in three species of Agetolites from the Upper Ordovician in Yushan County, Jiangxi Province of China. Agetolites is a peculiar coral possessing features of both tabulate （e.g., mural pores） and rugose corals （e.g., welldeveloped septa）. Septal patterns have long been considered to be indicative of the origin of corals, and the pattern of septal insertion in Agetolites has been known to be typical of rugosans. This study, however, reveals that the patterns in Ageto lites are rather random and cannot be an indication of its rugosan affinity. It is suggested that Agetolites probably has a closer phylogenetic relation with tabulates than with either rugosans or scleractinians. Two insertion patterns of the first six septa were detected （Types I and II）. Type I is interpreted as scleractinian pattern whereas Type II as typical pattern of rugosans. Types 1 and 2 are septal patterns of the second stage recognized in this study. Type 1 insertion occurs in six sectors located in the center of each interseptal space, suggesting scleractinian pattern of insertion. Type 2 insertion occurs in four sectors that are comparable with alar and counter sectors in rugose corals. Four patterns of the third （Types AD） and fourth stages （Types ad） of septal insertion have also been recognized in Agetolites. Type A only occurs in two adjacent sectors possibly due to the in completeness of septal development. Type B presents rugosan pattern. Types C and D resemble scleractinian pattern in most aspects. Types a, b, and c present no clear attribution to rugosan or scleractinian pattern probably due to the incompleteness of septal development whereas Type d is observable in rugose corals.
