title: Morphology, morphogenesis and small-subunit rRNA gene sequence of the novel brackish-water ciliate Strongylidium orientale sp. nov. (Ciliophora, Hypotrichia).
abstract: A novel stichotrich ciliate, Strongylidium orientale sp. nov., was discovered from a mangrove river in Hong Kong, southern China, and its morphology was investigated through observations in vivo and after protargol impregnation. Cells are 80-120 × 35-50 µm in vivo and fusiform in shape, with rounded anterior and tapered posterior ends. It is characterized by its brackish habitat and by the presence of two types of cortical granules arranged irregularly throughout the cortex. Morphogenetic events of cell division and physiological reorganization are described. The main ontogenetic features were: (i) only the posterior portion of the parental adoral zone of membranelles was renewed by dedifferentiation of the old structures; (ii) the oral primordium in the opisthe occurred apokinetally; (iii) the left and right ventral rows originated intrakinetally and the final left ventral row was spliced from two cirri from the frontoventral cirral anlage, a short cirral row from the anlage for the right ventral row and a long cirral row which was formed from the whole anlage of the left ventral row; (iv) the marginal rows developed intrakinetally; (v) the dorsal kineties replicated entirely de novo and did not fragment; and (vi) the two macronuclear nodules fused into a mass and then divided. Based on small-subunit rRNA gene sequences, phylogenetic analyses showed a close relationship with its congener Strongylidium pseudocrassum and with the genus Pseudouroleptus.
authors: Laboratory of Protozoology, Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao 266003, PR China.
authors: Xumiao
authors: X
authors: Chen
authors: College of Life Sciences, Graduate University of the Chinese Academy of Sciences, 19A Yuquanlu, Beijing 100049, PR China.
authors: Miao
authors: M
authors: Miao
authors: Laboratory of Protozoology, Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao 266003, PR China.
authors: Honggang
authors: H
authors: Ma
authors: The Key Laboratory of Biomedical Information Engineering Ministry of Education, Department of Biology and Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, PR China.
authors: Chen
authors: C
authors: Shao
authors: Zoology Department, King Saud University, Riyadh 11451, Saudi Arabia.
authors: Khaled A S
authors: KAS
authors: Al-Rasheid
mesh_terms: D016054:DNA, Protozoan / Q000235:genetics; D020459:Genes, rRNA; D006723:Hong Kong; D016810:Hypotrichida / Q000145:classification* / Q000166:cytology / Q000235:genetics; D008969:Molecular Sequence Data; D010802:Phylogeny; D045483:Rivers / Q000382:microbiology; D054712:Salinity; D017422:Sequence Analysis, DNA
chemical_list: D016054:DNA, Protozoan