Tau tubulin kinase is required for spermatogenesis and development of motile cilia in planarian flatworms

Cilia are microtubule-based structures that protrude from the apical surface of cells to mediate motility, transport, intracellular signaling, and environmental sensing. Tau tubulin kinases (TTBKs) destabilize microtubules by phosphorylating microtubule-associated proteins (MAPs) of the MAP2/Tau family, but also contribute to the assembly of primary cilia during embryogenesis. Expression of TTBKs is enriched in testicular tissue, but their relevance to reproductive processes is unknown. We identified six TTBK homologues in the genome of the planarian Schmidtea mediterranea ( Smed-TTBK-a, -b, -c, -d, -e, and -f), all of which are preferentially expressed in testes. Inhibition of TTBK paralogues by RNA interference (RNAi) revealed a specific requirement for Smed-TTBK-d in postmeiotic regulation of spermatogenesis. Disrupting expression of Smed-TTBK-d results in loss of spermatozoa, but not spermatids. In the soma, Smed-TTBK-d RNAi impaired the function of multiciliated epidermal cells in propelling planarian movement, as well as the osmoregulatory function of protonephridia. Decreased density and structural defects of motile cilia were observed in the epidermis of Smed-TTBK-d(RNAi) by phase contrast, immunofluorescence, and transmission electron microscopy. Altogether, these results demonstrate that members of the TTBK family of proteins are postmeiotic regulators of sperm development and also contribute to the formation of motile cilia in the soma.

Download Full-text

Ultrastructural evidence for an unusual mode of ciliogenesis in mouse multiciliated epithelia

Microscopy ◽

10.1093/jmicro/dfaa074 ◽

2020 ◽

Author(s):

Keishi Narita ◽

Sen Takeda

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Primary Cilia ◽

Single Cells ◽

Wild Type Mouse ◽

Wild Type ◽

Brain Ventricles ◽

Ultrastructural Evidence ◽

Transmission Electron ◽

Motile Cilia

Abstract Multiciliogenesis is a cascading process for generating hundreds of motile cilia in single cells. In vertebrates, this process has been investigated in the ependyma of brain ventricles and the ciliated epithelia of the airway and oviduct. Although the early steps to amplify centrioles have been characterized in molecular detail, subsequent steps to establish multicilia have been relatively overlooked. Here, we focused on unusual cilia-related structures previously observed in wild-type mouse ependyma using transmission electron microscopy and analyzed their ultrastructural features and the frequency of their occurrence. In the ependyma, $\sim$5% of cilia existed as bundles; while the majority of the bundles were paired, bundles of more than three cilia were also found. Furthermore, apical protrusions harboring multiple sets of axonemes were occasionally observed (0–2 per section), suggesting an unusual mode of ciliogenesis. In trachea and oviduct epithelia, ciliary bundles were absent, but protrusions containing multiple axonemes were observed. At the base of such protrusions, certain axonemes were completely enwrapped by membranes, whereas others remained incompletely enwrapped. These data suggested that the late steps of multiciliogenesis might include a unique process underlying the development of cilia, which is distinct from the ciliogenesis of primary cilia.

Download Full-text

Progress in ciliary ion channel physiology

The Journal of General Physiology ◽

10.1085/jgp.201611696 ◽

2016 ◽

Vol 149 (1) ◽

pp. 37-47 ◽

Cited By ~ 22

Author(s):

Juan Lorenzo Pablo ◽

Paul G. DeCaen ◽

David E. Clapham

Keyword(s):

Ion Channels ◽

Primary Cilia ◽

Apical Surface ◽

Fallopian Tubes ◽

Brain Ventricles ◽

Olfactory Cells ◽

Motile Cilia ◽

And Function ◽

Signaling Components ◽

Microtubule Doublet

Mammalian cilia are ubiquitous appendages found on the apical surface of cells. Primary and motile cilia are distinct in both morphology and function. Most cells have a solitary primary cilium (9+0), which lacks the central microtubule doublet characteristic of motile cilia (9+2). The immotile primary cilia house unique signaling components and sequester several important transcription factors. In contrast, motile cilia commonly extend into the lumen of respiratory airways, fallopian tubes, and brain ventricles to move their contents and/or produce gradients. In this review, we focus on the composition of putative ion channels found in both types of cilia and in the periciliary membrane and discuss their proposed functions. Our discussion does not cover specialized cilia in photoreceptor or olfactory cells, which express many more ion channels.

Download Full-text

A Study on the Fine Structure of the Lateral Line Organ of the Sea Eel

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100073684 ◽

1973 ◽

Vol 31 ◽

pp. 648-649

Author(s):

K. Hama

Keyword(s):

Fine Structure ◽

Electron Microscope ◽

Lateral Line ◽

Low Frequency ◽

Sensory Cells ◽

Apical Surface ◽

Voltage Electron ◽

Sensory Epithelia ◽

Low Frequency Vibration ◽

Transmission Electron

The lateral line organs of the sea eel consist of canal and pit organs which are different in function. The former is a low frequency vibration detector whereas the latter functions as an ion receptor as well as a mechano receptor.The fine structure of the sensory epithelia of both organs were studied by means of ordinary transmission electron microscope, high voltage electron microscope and of surface scanning electron microscope.The sensory cells of the canal organ are polarized in front-caudal direction and those of the pit organ are polarized in dorso-ventral direction. The sensory epithelia of both organs have thinner surface coats compared to the surrounding ordinary epithelial cells, which have very thick fuzzy coatings on the apical surface.

Download Full-text

Transmission electron microscopy of composite materials

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100107125 ◽

1988 ◽

Vol 46 ◽

pp. 1012-1015

Author(s):

K.P.D. Lagerlof

Keyword(s):

Composite Materials ◽

Physical Properties ◽

Structural Defects ◽

Structural Composites ◽

Multiphase Materials ◽

Structural Reinforcement ◽

Transmission Electron ◽

Reinforced Fiber ◽

Particulate Reinforced Composites ◽

Definition Of

Although most materials contain more than one phase, and thus are multiphase materials, the definition of composite materials is commonly used to describe those materials containing more than one phase deliberately added to obtain certain desired physical properties. Composite materials are often classified according to their application, i.e. structural composites and electronic composites, but may also be classified according to the type of compounds making up the composite, i.e. metal/ceramic, ceramic/ceramie and metal/semiconductor composites. For structural composites it is also common to refer to the type of structural reinforcement; whisker-reinforced, fiber-reinforced, or particulate reinforced composites [1-4].For all types of composite materials, it is of fundamental importance to understand the relationship between the microstructure and the observed physical properties, and it is therefore vital to properly characterize the microstructure. The interfaces separating the different phases comprising the composite are of particular interest to understand. In structural composites the interface is often the weakest part, where fracture will nucleate, and in electronic composites structural defects at or near the interface will affect the critical electronic properties.

Download Full-text

Dechannealing Study of Nanocrystalline Si:H Layers Produced by High Dose Hydrogen Irradiation of Silicon Crystals

MRS Proceedings ◽

10.1557/proc-536-499 ◽

1998 ◽

Vol 536 ◽

Author(s):

V. P. Popov ◽

A. K. Gutakovsky ◽

I. V. Antonova ◽

K. S. Zhuravlev ◽

E. V. Spesivtsev ◽

...

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Rutherford Backscattering Spectrometry ◽

Nanocrystalline Structure ◽

Structural Defects ◽

High Dose ◽

Silicon Crystals ◽

Strong Energy ◽

Transmission Electron ◽

Hydrogen Implantation

AbstractA study of Si:H layers formed by high dose hydrogen implantation (up to 3x107cm-2) using pulsed beams with mean currents up 40 mA/cm2 was carried out in the present work. The Rutherford backscattering spectrometry (RBS), channeling of He ions, and transmission electron microscopy (TEM) were used to study the implanted silicon, and to identify the structural defects (a-Si islands and nanocrystallites). Implantation regimes used in this work lead to creation of the layers, which contain hydrogen concentrations higher than 15 at.% as well as the high defect concentrations. As a result, the nano- and microcavities that are created in the silicon fill with hydrogen. Annealing of this silicon removes the radiation defects and leads to a nanocrystalline structure of implanted layer. A strong energy dependence of dechanneling, connected with formation of quasi nanocrystallites, which have mutual small angle disorientation (<1.50), was found after moderate annealing in the range 200-500°C. The nanocrystalline regions are in the range of 2-4 nm were estimated on the basis of the suggested dechanneling model and transmission electron microscopy (TEM) measurements. Correlation between spectroscopic ellipsometry, visible photoluminescence, and sizes of nanocrystallites in hydrogenated nc-Si:H is observed.

Download Full-text

Structural Analysis of Jumbo Coliphage phAPEC6

International Journal of Molecular Sciences ◽

10.3390/ijms21093119 ◽

2020 ◽

Vol 21 (9) ◽

pp. 3119 ◽

Cited By ~ 3

Author(s):

Jeroen Wagemans ◽

Jessica Tsonos ◽

Dominique Holtappels ◽

Kiandro Fortuna ◽

Jean-Pierre Hernalsteens ◽

...

Keyword(s):

Electron Microscopy ◽

Capsid Protein ◽

Tem Analysis ◽

Host Interaction ◽

Cryo Electron Microscopy ◽

Transmission Electron ◽

Tail Sheath ◽

Associated Proteins ◽

Contractile Tail ◽

Phage Capsid

The phAPEC6 genome encodes 551 predicted gene products, with the vast majority (83%) of unknown function. Of these, 62 have been identified as virion-associated proteins by mass spectrometry (ESI-MS/MS), including the major capsid protein (Gp225; present in 1620 copies), which shows a HK97 capsid protein-based fold. Cryo-electron microscopy experiments showed that the 350-kbp DNA molecule of Escherichia coli virus phAPEC6 is packaged in at least 15 concentric layers in the phage capsid. A capsid inner body rod is also present, measuring about 91 nm by 18 nm and oriented along the portal axis. In the phAPEC6 contractile tail, 25 hexameric stacked rings can be distinguished, built of the identified tail sheath protein (Gp277). Cryo-EM reconstruction reveals the base of the unique hairy fibers observed during an initial transmission electron microscopy (TEM) analysis. These very unusual filaments are ordered at three annular positions along the contractile sheath, as well as around the capsid, and may be involved in host interaction.

Download Full-text

Towards 3D image-based nanocrystallography by means of transmission electron goniometry

MRS Proceedings ◽

10.1557/proc-839-p4.3 ◽

2004 ◽

Vol 839 ◽

Cited By ~ 1

Author(s):

Peter Moeck ◽

Wentao Qin ◽

Philip B. Fraundorf

Keyword(s):

Lattice Structure ◽

Three Dimensions ◽

Structural Defects ◽

Transmission Electron ◽

Means Of Transmission ◽

Z Contrast ◽

Individual Nanoparticles ◽

Nanocrystal Model ◽

The Ideal

ABSTRACTIt is well known that the crystallographic phase and morphology of many materials changes with the crystal size in the tens of nanometer range and that many nanocrystals possess structural defects in excess of their equilibrium levels. A need to determine the ideal and real structure of individual nanoparticles, therefore, arises. High-resolution phase-contrast transmission electron microscopy (TEM) and atomic resolution Z-contrast scanning TEM (STEM) when combined with transmission electron goniometry offer the opportunity of develop dedicated methods for the crystallographic characterization of nanoparticles in three dimensions. This paper describes tilt strategies for taking data from individual nanocrystals “as found”, so as to provide information on their lattice structure and orientation, as well as on the structure and orientation of their surfaces and structural defects. Internet based java applets that facilitate the application of this technique for cubic crystals with calibrated tilt-rotation and double-tilt holders are mentioned briefly. The enhanced viability of image-based nanocrystallography in future aberration-corrected TEMs and STEMs is illustrated on a nanocrystal model system.

Download Full-text

Polaris, a protein disrupted inorpkmutant mice, is required for assembly of renal cilium

AJP Renal Physiology ◽

10.1152/ajprenal.00273.2001 ◽

2002 ◽

Vol 282 (3) ◽

pp. F541-F552 ◽

Cited By ~ 169

Author(s):

Bradley K. Yoder ◽

Albert Tousson ◽

Leigh Millican ◽

John H. Wu ◽

Charles E. Bugg ◽

...

Keyword(s):

Primary Cilia ◽

Collecting Duct ◽

Physiological Role ◽

Duct Cell ◽

Cystic Kidney Disease ◽

Cystic Kidney ◽

Apical Surface ◽

Cystic Disease ◽

Cortical Collecting Duct

Cilia are organelles that play diverse roles, from fluid movement to sensory reception. Polaris, a protein associated with cystic kidney disease in Tg737°rpkmice, functions in a ciliogenic pathway. Here, we explore the role of polaris in primary cilia on Madin-Darby canine kidney cells. The results indicate that polaris localization and solubility change dramatically during cilia formation. These changes correlate with the formation of basal bodies and large protein rafts at the apical surface of the epithelia. A cortical collecting duct cell line has been derived from mice with a mutation in the Tg737 gene. These cells do not develop normal cilia, which can be corrected by reexpression of the wild-type Tg737 gene. These data suggest that the primary cilia are important for normal renal function and/or development and that the ciliary defect may be a contributing factor to the cystic disease in Tg737°rpkmice. Further characterization of these cells will be important in elucidating the physiological role of renal cilia and in determining their relationship to cystic disease.

Download Full-text

TULP3 is required for localization of membrane-associated proteins ARL13B and INPP5E to primary cilia

Biochemical and Biophysical Research Communications ◽

10.1016/j.bbrc.2018.12.109 ◽

2019 ◽

Vol 509 (1) ◽

pp. 227-234 ◽

Cited By ~ 10

Author(s):

Sarina Han ◽

Ko Miyoshi ◽

Sho Shikada ◽

Genki Amano ◽

Yinshengzhuoma Wang ◽

...

Keyword(s):

Primary Cilia ◽

Associated Proteins

Download Full-text

Study on Dispersion and Characterization of Functionalized MWCNTs Prepared by Wet Oxidation

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.661.8 ◽

2014 ◽

Vol 661 ◽

pp. 8-13 ◽

Cited By ~ 10

Author(s):

Intan Syaffinazzilla Zaine ◽

N.A.M. Napiah ◽

Azmi Mohamad Yusof ◽

A.N. Alias ◽

A.M.M. Ali ◽

...

Keyword(s):

Electron Microscopy ◽

Relative Intensity ◽

Colloidal Stability ◽

Structural Defects ◽

Wet Oxidation ◽

Defect Level ◽

Transmission Electron ◽

Vis Spectroscopy ◽

Functionalized Mwcnts

The MWCNTs was functionalized by refluxing commercial MWCNTs (a-MWCNTs) in concentrated HNO3/H2SO4 (3:1 v/v) at 100°C for 6 hours. The dispersion of a-MWCNTs and functionalized MWCNTs (f-MWCNTs) were observed after 1 hour sonication in ethanol. Both samples were characterized by UV-vis spectroscopy for dispersion behavior. The dried f-MWCNTs and a-MWCNTs were characterized by Raman spectroscopy to estimate the defect level. The morphology of the samples were analyzed by Transmission Electron Microscopy (TEM). The f-MWCNTs was well dispersed in ethanol within 2 weeks of observations period. The colloidal stability of a-MWCNTs was low as it was easily sediment after 24 hours. The UV-vis spectra of f-MWCNTs show maximum absorbance at 250 nm meanwhile no absorbance was observed for a-MWCNTs. Analysis from Raman spectrum shows that the f-MWCNTs have relative intensity of 1.101 which is higher than a-MWCNTs that have relative intensity of 0.935. The image from TEM revealed that the f-MWCNTs have structural defects and the absence of amorphous carbon on sidewall meanwhile the a-MWCNTs indicate otherwise.

Download Full-text