Surface Cilia Research Articles

Morphological Observation and Transcriptome Analysis of Ciliogenesis in Urechis unicinctus (Annelida, Echiura).

During the early development of marine invertebrates, planktic larvae usually occur, and their body surfaces often form specific types of cilia that are involved in locomotion and feeding. The echiuran worm Urechis unicinctus sequentially undergoes the formation and disappearance of different types of body surface cilia during embryonic and larval development. The morphological characteristics and molecular mechanisms involved in the process remain unclear. In this study, we found that body surface cilia in U. unicinctus embryos and larvae can be distinguished into four types: body surface short cilia, apical tufts, circumoral cilia and telotrochs. Further, distribution and genesis of the body surface cilia were characterized using light microscope and electron microscope. To better understand the molecular mechanism during ciliogenesis, we revealed the embryonic and larval transcriptome profile of the key stages of ciliogenesis in U. unicinctus using RNA-Seq technology. A total of 29,158 differentially expressed genes (DEGs) were obtained from 24 cDNA libraries by RNA-Seq. KEGG pathway enrichment results showed that Notch, Wnt and Ca2+ signaling pathways were significantly enriched during the occurrence of apical tufts and circumoral cilia. Furthermore, all DEGs were classified according to their expression pattern, and DEGs with similar expression pattern were grouped into a module. All DEG co-expression modules were correlated with traits (body surface short cilia, apical tufts, circumoral cilia and telotrochs) by WGCNA, the results showed DEGs were divided into 13 modules by gene expression patterns and that the genes in No. 7, No. 8 and No. 10 modules were to be highly correlated with the occurrence of apical tufts, circumoral cilia and telotrochs. The top 10 hub genes in the above three modules were identified to be highly correlated with ciliogenesis, including the reported cilium-related gene Cnbd2 and unreported cilium-related candidate genes FAM181B, Capsl, Chst3, TMIE and Innexin. Notably, Innexin was included in the top10 hub genes of the two modules (No. 7 and No. 8), suggesting that Innexin may play an important role in U. unicinctus apical tufts, circumoral cilia and telotrochs genesis. This study revealed the characteristics of ciliogenesis on the body surface of U. unicinctus embryos and larvae, providing basic data for exploring the molecular mechanism of ciliogenesis on the body surface.

Tubulysins are Essential for the Preying of Ciliates by Myxobacteria.

Tubulysins are bioactive secondary metabolites produced by myxobacteria that promote microtubule disassembly. Microtubules are required for protozoa such as Tetrahymena to form cilia and flagella. To study the role of tubulysins in myxobacteria, we co-cultured myxobacteria and Tetrahymena. When 4000 Tetrahymena thermophila and 5.0×108 myxobacteria were added to 1 ml of CYSE medium and co-cultured for 48 h, the population of T. thermophila increased to more than 75,000. However, co-culturing tubulysin-producing myxobacteria, including Archangium gephyra KYC5002, with T. thermophila caused the population of T. thermophila to decrease from 4000 to less than 83 within 48 h. Almost no dead bodies of T. thermophila were observed in the culture medium. Co-culturing of T. thermophila and the A. gephyra KYC5002 strain with inactivation of the tubulysin biosynthesis gene led to the population of T. thermophila increasing to 46,667. These results show that in nature, most myxobacteria are preyed upon by T. thermophila, but some myxobacteria prey on and kill T. thermophila using tubulysins. Adding purified tubulysin A to T. thermophila changed the cell shape from ovoid to spherical and caused cell surface cilia to disappear.

Self-Assembly Magnetic Chain Unit for Bulk Biomaterial Actuation

Untethered microrobot has been regarded as one of the most powerful tools for performing specific in vitro/vivo tasks, especially magnetic actuated microrobot owing to its biocompatible energy source. However, although numerous design and fabrication technologies of magnetic microrobot have been developed, the improvement of magnetic actuation manner reaches the limit, which mainly relies on the specific structure design (helix) or strong gradient magnetic field to realize locomotion. Inspired from surface cilia dependent paramecium swimming, this letter reports a new self-assembly magnetic actuation concept design for bulk biomaterial motion based on the partial asymmetrical heterofunction of magnetic chain units. Compared with the existing design and fabrication of magnetic microrobot actuators, our proposed self-assembly magnetic chain unit method is succinct, economical, structure unconstrained, and material unconstrained. In this work, the tanglesome bulk fiber fabrication based on flow-focusing microcapillary system is first introduced, which is utilized for structure unconstrained and material unconstrained actuation demonstration. Second, the six degrees of freedom electromagnetic coil system is proposed for presenting the magnetic actuation based on self-assembly magnetic chain units. After that, the self-assembly mechanism and magnetic control mechanism are developed to explain the fabrication and actuation procedure. Finally, the self-assembled magnetic chain units can achieve up to 150 $\mu$ m length during the fabrication process, which can actuate bulk biomaterial with much larger size than itself. The self-assembly magnetic chain unit and actuation experimental results verify the feasibility and practicability of the above-mentioned concepts. This research opens new prospects for magnetic microrobot actuation, which is expected to advance the biomedical area, such as for in vitro/vivo targeted therapy and organ-on-a-chip research.

Nanoscale Imaging of Primary Cilia with Scanning Ion Conductance Microscopy.

Primary cilia are hair-like sensory organelles whose dimensions and location vary with cell type and culture condition. Herein, we employed scanning ion conductance microscopy (SICM) to visualize the topography of primary cilia from different cell types. By combining SICM with fluorescence imaging, we successfully distinguished between surface cilia that project outward from the cell surface and subsurface cilia that are trapped below it. The nanoscale structure of the ciliary pocket, which cannot be easily identified using a confocal fluorescence microscope, was observed in SICM images. Furthermore, we developed a topographic reconstruction method using current-distance profiles to evaluate the relationship between set point and topographic image and found that a low set point is important for detecting the true topography of a primary cilium using hopping mode SICM.

Transcriptomes and expression profiling of deep-sea corals from the Red Sea provide insight into the biology of azooxanthellate corals

Despite the importance of deep-sea corals, our current understanding of their ecology and evolution is limited due to difficulties in sampling and studying deep-sea environments. Moreover, a recent re-evaluation of habitat limitations has been suggested after characterization of deep-sea corals in the Red Sea, where they live at temperatures of above 20 °C at low oxygen concentrations. To gain further insight into the biology of deep-sea corals, we produced reference transcriptomes and studied gene expression of three deep-sea coral species from the Red Sea, i.e. Dendrophyllia sp., Eguchipsammia fistula, and Rhizotrochus typus. Our analyses suggest that deep-sea coral employ mitochondrial hypometabolism and anaerobic glycolysis to manage low oxygen conditions present in the Red Sea. Notably, we found expression of genes related to surface cilia motion that presumably enhance small particle transport rates in the oligotrophic deep-sea environment. This is the first study to characterize transcriptomes and in situ gene expression for deep-sea corals. Our work offers several mechanisms by which deep-sea corals might cope with the distinct environmental conditions present in the Red Sea As such, our data provide direction for future research and further insight to organismal response of deep-sea coral to environmental change and ocean warming.

Life cycle of Craspedacusta sowerbyi xinyangensis

Abstract To explore the life cycle of Craspedacusta, the authors collected male and female specimens of the Craspedacusta sowerbyi xinyangensis in a small fire-fighting pond in Ningbo, Zhejiang Province in July, 2005 and 2006. The development of C. sowerbyi xinyangensis was studied from zygote to medusa by means of light microscopy and digital camera. The zygotes of C. sowerbyi xinyangensis are globular and smooth (90 - 105 μm diameter) and have an equal, total cleavage to the two-cell stage 15 min after fertilization. The embryos enter the four-cell stage after another 15 min and become multicellular embryos after 3h 15 min. At this stage the embryos have a diameter similar to fertilized eggs but have uneven surfaces that are distinct from the smooth surfaces of the uncleaved zygotes. Solid gastrulae are formed 7 h after fertilization. These are spherical planulae with short surface cilia that begin to swim in slow clockwise circles. After 12 h, they lose their cilia, cease swimming and become elongated planulae with one end larger than the other. Rod-like planulae, similar in thickness at both ends, are formed after an additional 7 h. After 4 days, the planulae develop into tiny polyps having two germ layers and a gastrovascular cavity. The polyp mouth is 50 - 62 µm in diameter, lacking tentacles but having nematocysts around the mouth. Planulae become mature polyps after 10 days (15 days after fertilization). Medusa buds (45 - 88 μm diameter) are formed by polyp budding, which soon become free-living medusae with 8 tentacles (380 - 620 μm diameters). Sometimes, the movement of frustules, which are formed by the polyps and similar to planulae in morphology can also be observed.

A new brooding species of the biscuit star Tosia (Echinodermata:Asteroidea:Goniasteridae), distinguished by molecular, morphological and larval characters

The biscuit star Tosia australis Gray, 1840 is a well known component of the shallow rocky reef fauna of south-eastern Australia. The putative T. australis species complex was subjected to reproductive, morphometric and molecular analyses. Molecular analyses of the data from three markers (mitochondrial COI and 16S rRNA and the nuclear non-coding region ITS2) confirmed the presence of a cryptic species, the morphology of which does not agree with any of the existing nominal species. Two separate reproductive modes were observed within the complex and documented via scanning electron microscopy. T. neossia, sp. nov., described herein from south-eastern Australia, is shown to release gametes from gonopores on the actinal surface. Embryos develop first into non-feeding, non-swimming brachiolaria, and then into tripod brachiolaria before metamorphosis. No surface cilia are present at any point throughout development of T. neossia. T. australis sensu stricto is shown to release gametes from the abactinal surface. Embryos develop into non-feeding, swimming brachiolaria before metamorphosis. Whereas T. australis var. astrologorum is confirmed as synonymous with T. australis, the status of the putative Western Australian taxon T. nobilis remains unresolved.

Embryonic motility and hatching success of Ambystoma maculatum are influenced by a symbiotic alga

To augment O2supply through the jelly mass and egg capsule, embryonic yellow-spotted salamanders ( Ambystoma maculatum (Shaw, 1802)) take advantage of a unicellular alga, Oophila ambystomatis . Convective currents from surface cilia, however, may also enhance O2transport, whereas muscular contractions could either enhance delivery or contribute to O2consumption. Embryonic motion is, therefore, potentially vital to salamander development. We examined embryonic motility across multiple developmental stages, survivorship, and hatching timing in response to different algal levels by rearing salamander egg masses under three different diel light cycles: 24 h dark, 12 h light, and 24 h light per day. Embryos raised in continuous light hatched synchronously and at slightly earlier developmental stages than embryos raised in the dark or in 12 h light per day. We removed eggs at multiple stages to examine embryonic rotation and muscular contraction rates under 180 min periods of both light and dark. Rotational movements occurred more frequently in alga-free than in algae-inhabited eggs, and more frequently in algae-inhabited eggs in the dark than in light. At later developmental stages, muscular contractions were more frequent in embryos from algae-inhabited egg masses in light than those in the dark; thus embryos with less O2reduced muscular activity, thereby reducing energy consumption when O2availability was compromised.

The Effect of an Expandable Polyvinyl Acetate (Merocel) Pack on the Healing of the Nasal Mucosa of Sheep

There is a lack of knowledge about the healing of the nasal respiratory mucosa after endoscopic sinus surgery (ESS). Nasal packs often are placed after ESS in an attempt to improve hemostasis and reduce adhesion formation. Most nasal packs need to be removed in the postoperative period. This is uncomfortable for the patient and the affect of these packs on the healing process is unknown. We have standardized the sheep as a suitable animal model to examine the healing of the nasal epithelium after ESS. The nasal mucosa of sheep was wounded under endoscopic guidance and either packed with expandable polyvinyl acetate-based pack (Merocel), which was removed at the 5th postoperative day, or left unpacked to serve as control. Serial biopsies of the wounded area were taken every 28 days, up to 112 days postwounding, for examination using light and scanning electron microscopy. There was no significant difference in the rate of reepithelialization between the packed and control sides of the sheep (p > 0.05). There was no significant difference in the total amount of surface cilia coverage between the packed and control sides at any time points (p > 0.05). There was no significant difference in the maturity of the cilia between the packed and control sides at any time points (p > 0.05). The use of Merocel packing postoperatively neither impairs nor promotes wound healing in the postoperative period.

Odd mating-type substances may work as precursor molecules of even mating-type substances in Paramecium caudatum.

Mating-type substances are key molecules in the sexual recognition of the odd (O) and even (E) complementary mating-type cells in Paramecium caudatum. Indirect evidence suggested that the substances were proteins and were located on ventral surface cilia. Monoclonal antibodies inhibiting the mating reactivity of the O cells have been obtained. Using these antibodies, we tried to detect antigen molecules as dot-blot signals. Strong dot-blot signals of antigens were only detected from the mating reactive cells, but they were not detected from the well-fed and starved cells without mating reactivity. In addition to identifying the antigen on cilia and cytoplasm of the O cell, the antigen was detected from the cytoplasm of the E cells but never from their cilia. Furthermore, extracts of the E cells induced mating reaction with the living E cells but not with O cells. Thus, the O mating-type substances exist in the cytoplasm of the E mating-type cells, supporting strongly the hypothesis that O mating-type substances are precursor molecules of the E mating-type substances.

上顎前歯部に発生した腺性歯原性嚢胞の１例

Glandular odontogenic cyst is a rare jaw bone cyst of odontogenic origin, first described in 1988 by Gardner et al.Radiologically, a well-defined unilocular cyst lesion is seen. Histologic features include a thin layer of epithelium with surface cilia and glandular or pseudoglandular structures.A case of glandular odontogenic cyst of the maxilla is reported.

A new monoclonal antibody inhibiting mating agglutination in <i>Paramecium caudatum</i>

Mating reaction occurs between the cells of the odd and even complementary mating types in Paramecium caudatum. The molecules involved in this cell-to-cell sexual recognition called mating type substances are suggested to be proteins and exist on the ventral surface cilia of the cell. To obtain more varied epitopes, mating-reactive membrane vesicles reconstituted from odd mating type cilia of syngen 3 were used as antigen. A new monoclonal antibody XomO inhibiting the mating reactivity of both mating types was obtained. The unusual characteristic of XomO is the localization of the antigen, which particularly is recognized on basal portion, and not the whole length, of the ventral surface cilia. The antigen was suggested to be membrane protein and the detection of the antigen was correlated with the mating reactivity of the cells. These results suggest that the antigen of XomO is a substance involved in mating reaction under a dynamic-conformational change.

Effects of cryopreservation on the ultrastructural anatomy of 3‐segment Nereis virens larvae (Polychaeta)

Abstract. A transmission electron microscope study of fresh and cryopreserved Nereis virens larvae at the three chaetiger stage is described with special emphasis on examining the structure of the photoreceptors and surface ciliation of the head, the midgut epithelium, and muscle cells. Complex ectodermal structures such as the developing rhabdomeric adult eyes were unaffected by the cryopreservation procedure. Some loss of surface cilia on the prostomium was observed but is not life‐threatening though it may restrict ciliary swimming in the recovered larvae. Loss of pigment from the prostomium is caused by osmotic stress. Structural damage was observed in the digestive tissues of the larvae cryopreserved before or after the optimum stage of development. This damage is potentially more serious and may account for the relatively short time period during development where cryopreservation can be successfully applied.

High-Frequency Ventilation and Tracheal Injuries

Recent reports linking serious tracheal injuries to various forms of high-frequency ventilation prompted this study. We compared the tracheal histopathology seen following standard-frequency, conventional mechanical ventilation with that seen following high-frequency, conventional mechanical ventilation, and two different forms of high-frequency jet ventilation. Twenty-six adult cats were examined. Each was mechanically ventilated for 16 hours. Seven received standard-frequency, conventional mechanical ventilation at 20 breaths per minute. Seven received high-frequency, conventional mechanical ventilation at 150 breaths per minute. Six received high-frequency jet ventilation at 250 breaths per minute via the Instrument Development Corporation VS600 jet ventilator (IDC). Six received high-frequency jet ventilation at 400 breaths per minute via the Bunnell Life Pulse jet ventilator (BLP). A semiquantitative histopathologic scoring system graded tracheal tissue changes. All forms of high-frequency ventilation produced significant inflammation (erosion, necrosis, and polymorphonuclear leukocyte infiltration) in the trachea in the region of the endotracheal tube tip. Conventional mechanical ventilation produced less histopathology than any form of high-frequency ventilation. Of all of the ventilators examined, the BLP, the ventilator operating at the fastest rate, produced the greatest loss of surface cilia and depletion of intracellular mucus. IDC high-frequency jet ventilation and high-frequency, conventional mechanical ventilation produced nearly identical histologic injuries. In this study, significant tracheal damage occurred with all forms of high-frequency ventilation.(ABSTRACT TRUNCATED AT 250 WORDS)

The origin, distribution and disappearance of surface cilia during embryonic development of Rana pipiens as revealed by scanning electron microscopy

AbstractCilia begin to grow from the free surface of some ectodermal cells during the neural plate stage (stage 13). Ciliary growth is not closely synchronized between cells in the same embryo, but the number of ciliated cells increases greatly during neural fold development and further growth in length of pre‐existing cilia occurs. Ciliated cells are numerous and widely distributed over the surface of early tailbud stages. However, cilia do not develop on cells in the neural plate and inner sides of the neural fold, and only an occasional ciliated cell is observed on the surface of the paired suckers. The number of ciliated epidermal cells per embryo increases during tail growth (stages 18–22). Ciliated epidermal cells persist after hatching (stage 20), but regression of cilia can be detected in stage 24 larvae. By late stage 25, most of the cilia have disappeared and the morphological variations observed indicate that the process involves resorption of cilia. Non‐ciliated (secretory) ectodermal cells from the neurula onward to stage 25 synthesize granules which are released to provide a mucous‐like coat for the embryo and larva. The surface structure of both ciliated and non‐ciliated ectodermal cells is described in sections studied with the transmission electron microscope and compared to the surface architecture of both cell types observed with the scanning electron microscope.

Ultrastructural morphology of the normal nasal respiratory epithelium of the mouse.

AbstractThe nasal respiratory epithelium of the mouse has been studied at the ultrastructural level. The tissue was found to be a rather typical pseudostratified columnar ciliated epithelium, superficially different but basically similar to tracheal and bronchial epithelium in the same species, and clearly similar in most respects to that of other mammals. Four cell types were distinguished: ciliated columnar, secretory (goblet), intermediate, and basal.The ciliated cells, which exhibited typical surface cilia and microvilli, were characterized by a distinct stratification in the arrangement of subcellular components in their supranuclear cytoplasm. Beginning at the apical end and proceeding basally, the following strata were seen: an ectoplasmic region relatively free of organelles; an area rich in vesicular and tubular membrane profiles; a mitochondrial zone; a layer rich in ribosomes and polyribosomes; and a stratum of Golgi complexes.Secretory (goblet) cells were observed at various stages of secretion droplet accumulation. Cells in the earliest stage, characterized by a dense content of sER in the supranuclear cytoplasm, were similar to the “non‐ciliated” cells of the mouse's lower respiratory tract. Some of the secretory cells contained dilated cisternae of rER which were engorged with a relatively electron‐dense material. The possible significance of these inclusions is discussed.Unlike the other cell types, intermediate and basal cells displayed no features indicative of specialized function.

The fine structure of sensory receptor processes in the auricular epithelium of the planarian, Dugesia tigrina

The marginal epithelium of the lateral auricles of the planarian, Dugesia tigrina, includes a cell type with surface cilia and microvilli, a basal nucleus, and dense cytoplasm containing secretory vacuoles, Golgi elements, mitochondria and ribosomes. Through channels within the epithelial cytoplasm, cellular processes, interpreted as extensions of neurosensory receptor cells located in the subepidermis, project to the surface. The receptor processes, containing microtubules, mitochondria, vesicles and an agranular tubular reticulum, project beyond the epithelial cell surface; one or two cilia each emerge from a basal body in the apex of the projection. Close to the point of emergence to the epithelial surface, each cylindrical receptor process is surrounded by a collar-like septate junction between adjacent plasma membranes. The cilia of the projections differ from those of the epithelial cells in diameter, density of matrix and in the banding patterns of the rootlets. A few projections appear with the apex and basal body retracted below the epithelial surface. The possible function of these ciliated processes in sensory reception is discussed.