耳蜗动纤毛在听觉系统中的作用研究进展

听觉发生过程是一个比较复杂的且受到机体精密调控的过程。如果听觉发生过程出现异常,则会引起一定程度的听觉损失。听觉损失是一种常见的感觉缺陷性疾病,它会严重影响人类的日常交流能力,让生活变得极为不便。既往研究表明,动纤毛对于毛细胞发育及功能的调控是一个复杂的过程,动纤毛功能异常会导致耳蜗静纤毛束紊乱从而引发不同程度的听力损失。到目前为止,关于动纤毛的研究内容较少,主要集中于耳蜗毛细胞平面细胞极性方面的研究。因此,本文主要围绕耳蜗动纤毛的发生机制及其在听觉过程中的作用进行综述。

动纤毛轴丝的分子组装

纤毛/鞭毛是从细胞膜表面突出的真核细胞器,它能调节细胞运动及细胞周围液体流动,或者参与机体的感知功能,其异常会引发多种人类纤毛病。作为最早被发现的细胞器之一,纤毛一直是细胞生物学领域的重点研究对象,但是因结构大且复杂,其分子组装机制的揭示长期以来一直是个难题。近些年,随着冷冻电镜技术的发展,多个课题组先后报道了从衣藻到哺乳动物精子鞭毛的轴丝各部分高分辨率结构。该文综述了动纤毛的结构组成和最新的分子组装研究进展,重点描述了轴丝各个组成部分包括双联微管(DMT)、内外动力臂(IDA和ODA)、辐条结构(RS)、中央微管对(CP)和连接复合物(N-DRC)的蛋白组成和分布,为深入理解纤毛的组装过程和功能调节提供了科学依据。

气道纤毛运动分子生物学研究进展

气道纤毛运动功能是呼吸道防御机制的重要组成部分 ,纤毛运动的主要动力来源于纤毛轴动力臂。随着分子生物学的发展 ,目前已分离出几种与纤毛轴动力臂有关的基因 ,并对这些基因与纤毛运动功能障碍的关系进行了研究。

小鼠室管膜细胞体外培养及多纤毛形成过程分析

目的利用体外原代培养小鼠室管膜细胞(MEPC),表征其分化过程形态特征,纤毛的形成及摆动方式。方法通过将分离的新生小鼠端脑组织细胞进行特殊培养和分化,获得具有生理功能的MEPC。利用免疫组化方法跟踪MEPC分化过程中纤毛的形成,并在活细胞状态观察其纤毛摆动模式。结果分离的端脑细胞在特殊的培养条件下快速增殖,经过诱导分化可以得到具有多纤毛结构的MEPC。结论本研究利用改进的原代MEPC培养方案,成功获得具有免疫组化特征及正常多纤毛摆动特性的MEPC,并揭示了分化各个时期纤毛及相关结构的形态特征,为以MEPC为模型的研究奠定了基础。

Nature,Characteristics and Uitrastructure Observation of Fibers of Seven Kinds of Special Animals

[Objective]Aimed to study the nature,characteristics and ultrastructure of fibers of Ovis aries and several kinds of special animals.[Method]Wool,cashmere,alpaca,Bactrian camel hairs,rabbit hair,mohair and yak hair were used as the experimental materials,and scanning electron microscopy was used to observe their scale structure.[Result]The rake angle of wool was large with an average of 33.2°,the scale density was 16.2-34.9 scales/mm,the average height of scale was 12.95 μm,and the average thickness was 0.63 μm;the rake angle of cashmere was smaller than wool with an average of 20.6°,the scale density was of 10.3-15.6 scales/mm,the scale distance was large,the average height of scale was 16.09 μm,and the average thickness was 0.46 μm;the average rake angle of alpaca was 34.6°,with the average scale height of 5.85 μm,and average thickness of 0.33 μm;the average rake angle of camel hair was 33.5°,with the average scale height of 11.30 μm and average thickness of 0.37 μm;the average rake angle of rabbit hair was 31.2°,with average scale height of 7.03 μm and average thickness of 0.36 μm;the rake angle value of mohair was between wool and cashmere,and the average of which was 23.7°,the scale density value was also between the wool and cashmere,with the average scale height of 15.82 μm and average thickness of 0.61 μm;the average rake angle yak hair was 33.2°,with the average height of 9.08 μm and average thickness of 0.46 μm.[Conclusion]The results of this study could provide a basis for the identification of different fiber types.

听信息在毛细胞中的转导过程及模型

一、引言外耳接收的声波,经外耳道而达鼓膜,鼓膜的振动借小听骨使镫骨扣击前庭窗,引起前庭阶外淋巴液振动,从而振动前庭膜和蜗管的内淋巴液,于是引起基底膜内听弦的共振;当基膜振动时,毛细胞的纤毛触及盖膜弯曲,使毛细胞受到刺激,引起神经冲动,由位听神经的蜗神经传入脑的听中枢,这是产生听觉的基本过程。在这个过程中,听觉的感受器一毛细胞利用各种机械的、流体力学的、电的方法,

Population dynamics of marine ciliate Euplotes vannus (Protozoa, Ciliophora) in different artificial seawaters

To study population dynamics of marine ciliates in different artificial seawaters （ASW）, the population growth dynamics of a common marine ciliate Euplotes vannus were investigated using beef extract media and rice media for five types of ASW and natural seawater （NSW）. The results show that： （1） the population growth rate was in the order of NSW〉Flack ASW〉Nakamula ASW〉Schmadz ASW〉Oshima ASW〉Subow ASW and was considerably higher in rice media than in beef extract media （apart from Subow ASW）; （2） the maximum density of E. vannus in stationary phase in each treatment was ranked as Hack ASW〉Nakamula ASW〉Schmadz ASW〉NSW〉Oshima ASW〉Subow ASW, and was again higher in rice media than in beef extract media （except for Subow ASW）; （3） the exponential and stationary phases were longer in rice media than in beef extract media; （4） strains of E. vannus that had been domesticated for 〉1 year in ASW grew significantly slower, with lower maximum density and longer stationary phase than those isolated and maintained in NSW. It was demonstrated that： （1） E. vannus may grow well in Flack, Nakamula and Schmads ASW compared with NSW （mainly in terms of growth rate）; and （2） Oshima ASW is the preferred choice for stock cultures of E. vannus, but the ASWs Flack, Nakamula and Schmadz are preferred for mass culture. These findings suggest that these three ASWs are effective for the cultivation of marine protozoa for experimental studies on ecology, toxicology and molecular biology.

Molecular phylogeny and species separation of five morphologically similar Holosticha-complex ciliates(Protozoa, Ciliophora) using ARDRA riboprinting and multigene sequence data

To separate and redefine the ambiguous Holosticha-complex, a confusing group of hypotrichous ciliates, six strains belonging to five morphospecies of three genera, Holosticha heterofoissneri, Anteholosticha sp. popl, Anteholosticha sp. pop2, A. manca, A. gracilis and Nothoholostichafasciola, were analyzed using 12 restriction enzymes on the basis of amplified ribosomal DNA restriction analysis. Nine of the 12 enzymes could digest the DNA products, four （HinfⅠ, Hind Ⅲ, Msp Ⅰ, Taq Ⅰ） yielded species-specific restriction patterns, and Hind Ⅲ and Taq Ⅰ produced different pattems for two Anteholosticha sp. populations. Distinctly different restriction digestion haplotypes and similarity indices can be used to separate the species. The secondary structures of the five species were predicted based on the ITS2 transcripts and there were several minor differences among species, while two Anteholosticha sp. populations were identical. In addition, phylogenies based on the SSrRNA gene sequences were reconstructed using multiple algorithms, which grouped them generally into four clades, and exhibited that the genus Anteholosticha should be a convergent assemblage. The fact that Holosticha species clustered with the oligotrichs and choreotrichs, though with very low support values, indicated that the topology may be very divergent and unreliable when the number of sequence data used in the analyses is too low.

Phylogenetic relationships within the genus Aspidisca(Protozoa,Ciliophora,Euplotida) revealed by ITS1-5.8S-ITS2 region sequences

Abstract The internal transcribed spacer regions （ITS1 and ITS2） and 5.8S rRNA genes were sequenced in six populations of four Aspidisca species, namely A. leptaspis, A. orthopogon, A. rnagna and A. aculeata. Phylogenetic trees were constructed by means of Bayesian inference （BI）, Maximum Parsimony （MP）, Neighbor-Joining （NJ）, and Maximum Likelihood （ML） to assess the inter- and intra-species relationships within the genus Aspidisca. All trees show similar topologies with stable supports and indicate that： （1） four well known groups, i.e., Oligotrichia, Stichotrichia, Choreotrichia and Hypotrichia, are distinctly outlined within the class Spirotrichea, and all are monophyletic other than Hypotrichia; （2） members of Aspidisca can be distinguished well, based on the ITSI-5.SS-ITS2 region sequences, and A. leptaspis and A. magna shared a closer relationship than other species; （3） Aspidisca and Euplotes branch early in the subclass Hypotrichia. To compare the phylogenetic relationships based on different genes, SSU rRNA trees were also constructed with nearly the same species inclusion, which revealed different topologies of inter-species, inter-genera and inter-subclasses.

A General Overview of the Typical 18 Frontal-VentralTransverse Cirri Oxytrichidae s. l. Genera(Ciliophora, Hypotrichia)

Oxytrichidae s. l. ciliates usually have 18 frontal-ventral-transverse cirri which are clustered to six distinct groups usu- ally originating from six longitudinal primordia segregating 1, 3, 3, 3, 4, 4 cirri. During morphogenesis, three dorsal kinetics anlagen are primarily formed. Fragmentation of kinety 3 usually present, while sometimes secondarily lost. Dorsomarginal kineties are formed, while sometimes lost. Oxytrichids tend to have overlapping characters, e.g. cell shape and size, infraciliature, pellicle fea- tures. This makes a great problem for genera separation. In the present work, all typical 18 frontal-ventral-transverse-cirri Oxytrichi- dae s. 1. genera were revised systematically based on their living morphology, ciliature patterns and dorsal morphogenetic features. The outline of the genera, the schematic illustrations, and the key to typical 18 frontal-ventral-transverse-cirri genera of Oxytrichidae s. l. were clarified. Additionally, some morphological and morphogenetic patterns were summarized and compared.

Tolerance of ciliated protozoan Paramecium bursaria (Protozoa, Ciliophora) to ammonia and nitrites

The tolerance to ammonia and nitrites in freshwater ciliate Paramecium bursaria was measured in a conventional open system. The ciliate was exposed to different concentrations of ammonia and nitrites for 2h and 12h in order to determine the lethal concentrations. Linear regression analysis revealed that the 2h-LC50 value for ammonia was 95.94 mg/L and for nitrite 27.35 mg/L using probit scale method (with 95% confidence intervals). There was a linear correlation between the mortality probit scale and logarithmic concentration of ammonia which fit by a regression equation y=7.32x–9.51 (R2=0.98; y, mortality probit scale; x, logarithmic concentration of ammonia), by which 2 h–LC50 value for ammonia was found to be 95.50 mg/L. A linear correla- tion between mortality probit scales and logarithmic concentration of nitrite is also followed the regression equa- tion y=2.86x+0.89 (R2=0.95; y, mortality probit scale; x, logarithmic concentration of nitrite). The regression analysis of toxicity curves showed that the linear correlation between exposed time of ammonia-N LC50 value and ammonia-N LC50 value followed the regression equation y=2 862.85e-0.08x (R2=0.95; y, duration of exposure to LC50 value; x, LC50 value), and that between exposed time of nitrite-N LC50 value and nitrite-N LC50 value followed the regression equation y = 127.15e-0.13x (R2=0.91; y, exposed time of LC50 value; x, LC50 value). The results demonstrate that the tolerance to ammonia in P. bursaria is considerably higher than that of the larvae or juveniles of some metozoa, e.g. cultured prawns and oysters. In addition, ciliates, as bacterial predators, are likely to play a positive role in maintaining and improving water quality in aquatic environments with high-level ammonium, such as sewage treatment systems.

SHORT TIME DYNAMICS OF CILIATE ABUNDANCE IN THE BOHAI SEA (CHINA)

The ciliate community in the Bohai Sea (China) was studied from 23 September to 7 October 1998. A hurricane struck the study area between the two grid station investigations, which were six days apart. Six tintinnid species (Favella panamensis, Leptotintinnus nordqvisti, Tintinnopsis butschlii, T. karajacensis, T. Radix and Wangiella dicollaria) were identified. Total cililate abundance in the surface layer ranged from 20 to 770 ind/l. In the first grid investigation, Tintinnopsis karajacensis dominated in the warm, low salinity waters at the Huanghe River mouth. Aloricate ciliate sp.1 dominated in the cold, high salinity waters in the northwest of the study area and the Bohai Strait. In the second grid investigation, T. Karajacensis almost disappeared. The abundance of aloricate ciliate sp.1 decreased drastically. The aloricate ciliate sp.2 dominated at the Bohai Strait. The change of ciliate abundance may be due to the disturbance of hurricane.

Phylogeny of subclass Scuticociliatia(Protozoa,Ciliophora) using combined data inferred from genetic,morphological,and morphogenetic evidence

Gene sequence-based genealogies of scuticociliates are different from those produced by morphological analyses.For this reason,11 representative scuticociliates and two ambiguously related genera were chosen to test the ability of combined phylogenetic analyses using both gene sequences and morphological/morphogenetic characteristics.Analyses of both the SSrRNA gene sequences and the combined datasets revealed a consistent branching pattern.While the terminal branches and the order level relationships were generally well resolved,the family level relationships remain unresolved.However,two other trees based on ITS1-5.8S-ITS2 region sequences and morphological/morphogenetic characters showed limited information,due to a lack of informative sites in these two datasets.Our data suggest,however,that the combined analysis of morphological/morphogenetic characters and gene sequences did produce some changes to the phylogenetic estimates of this group.

Insights into the phylogeny of sporadotrichid ciliates (Protozoa, Ciliophora: Hypotricha) based on genealogical analyses of multiple molecular markers

The sporadotrichid ciliates are an especially diverse group. A number of investigators have studied the morphological, morphogenetic, and molecular relationships among members of this group. Despite this, a consistent classification is still lacking and several important questions about the phylogenetic relationships within this group remain unsolved. To improve our understanding of these relationships, we constructed phylogenetic trees using the nucleotide sequences of the small-subunit rRNA (SSrRNA) gene and amino acid sequences of actin I and α-tubulin. Analyses of SSrRNA gene sequences indicated that: 1) the Sporadotrichida sensu Lynn (2008) and the Oxytrichidae are polyphyletic; 2) the Uroleptus species, which are classified to urostylids, formed a sister group with the oxytrichids; 3) Halteria grandinella, which is grouped morphologically with oligotrich species, clustered within the oxytrichids. These results are congruent with previous studies based on SSrRNA gene sequences. However, the amino acid sequences of actin I and α-tubulin yielded different topologies. The main results are: 1) in all phylogenetic trees, the genus Oxytricha was paraphyletic; 2) Uroleptus was sister to a subset of Urostyla and Holosticha, albeit with low supporting values; 3) Halteria grandinella was separated distantly from the Oxytrichidae in trees inferred from actin I amino acid sequences but clustered with oligotrichids in the α-tubulin analysis. The inconsistency among the trees inferred from these different molecular markers may be caused by rapidly accumulated genetic characterizations of ciliates. Further studies with additional molecular markers and sampling of more taxa are expected to better address the relationships among sporadotrichids.

Molecular phylogeny of oligotrich genera Omegastrombidium and Novistrombidium(Protozoa,Ciliophora) for the systematical relationships within Family Strombidiidae

The phylogeny of the oligotrich ciliates is currently a hot debate despite the availability of both morphological and molecular data.In the present paper,further small subunit rRNA(SS rRNA) genes were analyzed from the Genera Omegastrombidium and Novistrombidium,as well as from Strombidium,and combined with three new SS rRNA sequences from Strombidium basimorphum,S.sulcatum population QD-1,and Novistrombidium testaceum population GD.The phylogenetic positions of these organisms were inferred using Bayesian inference,Maximum Likelihood,and Maximum Parsimony methods.The main results are:(1) the SS rRNA gene sequence analyses match the recent findings about the molecular evolution of oligotrichs,indicating that the family Strombidiidae is paraphyletic;(2) the Genus Omegastrombidium is separated from the Genus Strombidium,as shown in recent cladistic analyses;(3) morphospecies in Genus Novistrombidium,based on similarity of somatic ciliature,are separated from each other in all topological trees,indicating that this genus could be a paraphyletic group;(4) the molecular data indicate a possibility of paraphyly for the genus Strombidium;and(5) the similarities of the SS rRNA gene of specimens identified as S.sulcatum and S.inclinatum are 99.8%-100%.However,present knowledge on the oligotrichs sensu stricto is still insufficient and further studies based on both molecular and other technologies are required.

Acute Toxicities of Potassium Permanganate, Formalin, and Lugol's Iodine Solution to a Marine Ciliate, Pleuronema coronatum (Ciliophora, Scuticociliatida)

Acute toxicities of potassium permanganate, formalin, and Lugol’s iodine solution to a commonly occurred marine ciliate Pleuronema coronatum (Ciliophora, Scuticociliatida) were measured. Linear regression analysis of the results highlighted the close relationships between doses of the medicines and mortalities of the organisms, thus providing a capability to predict toxicity effects from the dose. Toxic effects of the medicines on the ciliates were described in the present paper, and the median lethal concentrations (LC 50 values) were given. Results of measurements indicated that 2 h-LC 50 and 12 h-LC 50 values of formalin on P. coronatum were 59.00×10 -6 and 43.57×10 -6, while those of Lugol’s solutions were 90.13 and 67.84×10 -6 respectively. The tolerance of P. coronatum to formalin is apparently lower than that to Lugol’s iodine solution and potassium permanganate is a suitable medicine to kill ciliates in short time.

Ecological functions of ciliated protozoa in marine ecosystem： effects of ammonium on the population growth of Euplotes vannus

The effects of ammonium on the population growth of the marine ciliate, Euplotes vannus, were examined using ecotoxicological method, h is showed that ammonium exerts inhibitory effects on the growth of the ciliate populations in a concentration-dependent way. Statistical analvsis reveals that the population growth dynamics exposed to ammoniunt-N concentration over 100mg/L are significantly different from that in the control at P 〈 0.05 level. Linear regression determined that the 24h, 36h, 48h, 60h, 72h and 84h IC50 values of ammonium-N are 19.68, 201.51, 167.49, 47.86, 50.43 and 43.11 concentration over 100mg/L, respectively （ P 〈 0.05; pH 8.2; salinity 28 ppt; temperature, 25℃ ）. The results indicate that the tolerance to ammonium in E. vannus is considerably higher than that of the larvae or juveniles of some metozoa, such as cuhured prawns and oysters. Therefore, it is believed that the high tolerance to ammonium is necessary for eiliated protozoa to play positive roles in maintaining and improving water quality in marine ecosystems, especially in the intensive aquacuhure waters with high-level ammonium. In addition, the correlation between /C50 values and exposure time was discussed.

Phylogenetic studies of four species of ciliate inferred from 16s-like small subunit rRNA gene sequences

The phylogenetic relationships of four ciliate genera （Urostyla, Euplotes, Stylonychia and Pseudokeronopsis）, which also are the important environment inspection species, were analyzed by the comparison of small subunit ribosomal RNA gene sequences. Euplotes appeared as an early branching group whose divergence from the hypotrichous line at a deep level was strongly supported by parsimony and matrix analyses. The analyses also supported the hypothesis that there were closely relationship between species in Urostyla and Holosticha. The sibling species Stylonychia mytilus and S. lemnae could be separated by the evolutionary analyses. Furthermore, Pseudokeronopsis rubra had relatively more closely relationship with the species in Holostichidae than that in Urostylidae based on the evolutionary distance value.

First Record and Redefinition of the Qingdao Population of Marine Ciliate Cardiostomatella vermiformis (Kahl, 1928) Corliss, 1960 (Protozoa, Ciliophora)

The living morphology and infraciliature of a marine ciliate, Cardiostomatella vermiformis isolated from a sand beach of the Jiaozhou Bay near Qingdao, China, were investigated by live observation, protargol and silver carbonate impregnation methods. Both the morphological and morphometric data largely agree with former records. Based on the data obtained, an improved diagnosis for Cardiostomatella vermiformis is supplied: Large marine Cardiostomatella with cylindrical body shape and several prolonged caudal cilia; cells in vivo about (90–500) μm×(30–120) μm; macronucleus beaded; single contractile vacuole caudally positioned; buccal apparatus conspicuously small, genus typical; three to six postoral kineties; 96-130 somatic kineties. This species is recorded for the first time in China.

ON THE MARINE CILIATE, Pseudocohnilembus hargisi(PROTOZOA, CILIOPHORA, SCUTICOCILIATIDA) WITH COMPARISON OF ITS RELATED SPECIES

The living morphology, nuclear apparatus, infraciliature and silverline system of the poorly known ciliate Pseudocohnilembus hargisi Evans & Thompson, 1964, collected from a shrimp culture pond in Qingdao, China, were examined by observation of the live specimen; and by the pyridinated carbonate method and Chatton Lwoff technique. The main characteristics: 13-14 (usually 13) longitudinal or slightly spirally arranged somatic kineties; single contractile vacuole with usually 2 (1-2) pores at posterior ends of the fourth and fifth somatic kineties to the right of the buccal cavity. Several related congeners were compared and morphometrically tabulated.