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Webology ◽  
2021 ◽  
Vol 18 (2) ◽  
pp. 1278-1294
Author(s):  
Mohammed Tareq Abdulwahhab ◽  
Anmar Adnan Khudhair Al-Dulaimi ◽  
Eman Jawad Ahmed Alkfaajy

The study aimed to reduce the phenomenon of government corruption by developing internal control systems using governance mechanisms, and the factors influencing their support to improve their professional quality, as one of the most important mechanisms of an effective internal control structure that affects the discovery and prevention of fraud and innovative practices, increasing the credibility and transparency of financial and control reports, and contributing to activation Practicing the system of governance, to reduce administrative deception and methods, to control and minimize corruption, and to raise the productive efficiency of government performance, by controlling public spending, preserving public money, and promoting economic rationalization in the use and exploitation of property General resources, and a questionnaire list was designed to achieve these goals, which was distributed to those interested in government internal control divided into three categories: financial monitors in the ministry, inspectors of the central apparatus, and government accountants. The study concluded the importance of applying governance mechanisms in raising the level of efficiency of government internal control systems, in order to reduce the manifestations of government corruption.


2021 ◽  
Author(s):  
Shimaa A. Abdellatef ◽  
Hisashi Tadakuma ◽  
Kangmin Yan ◽  
Takashi Fujiwara ◽  
Kodai Fukumoto ◽  
...  

AbstractDuring repetitive bending of cilia and flagella, axonemal dynein molecules move in an oscillatory manner along a microtubule (MT), but how the minus-end-directed motor dynein can oscillate back and forth is unknown. There are various factors that may regulate the dynein activities, e.g., the nexin-dynein regulatory complex, radial spokes, and central apparatus. In order to understand the basic mechanism of the oscillatory movement, we constructed a simple model system composed of MTs, outer-arm dyneins, and DNA origami that crosslinks the MTs. Electron microscopy (EM) showed patches of dynein molecules crossbridging two MTs in two opposite orientations; the oppositely oriented dyneins are expected to produce opposing forces. The optical trapping experiments showed that the dynein-MT-DNA-origami complex actually oscillate back and forth after photolysis of caged ATP. Intriguingly, the complex, when held at one end, showed repetitive bending motions. The results show that a simple system composed of ensembles of oppositely oriented dyneins, MTs, and inter-MT crosslinkers, without the additional regulatory structures, has an intrinsic ability to cause oscillation and repetitive bending motions.


2021 ◽  
Author(s):  
Kai Cai ◽  
Yanhe Zhao ◽  
Lei Zhao ◽  
Nhan Phan ◽  
Yuqing Hou ◽  
...  

‘9+2’ motile cilia contain 9 doublet microtubules and a central apparatus (CA) composed of two singlet microtubules with associated projections. The CA plays crucial roles in regulating ciliary motility. Defects in CA assembly or function usually result in motility-impaired or paralyzed cilia, which in humans causes disease. Despite their importance, the protein composition and functions of most CA-projections remain largely unknown. Here, we combined genetic, proteomic, and cryo-electron tomographic approaches to compare the CA of wild-type Chlamydomonas with those of three CA-mutants. Our results show that two proteins, FAP42 and FAP246, are localized to the L-shaped C1b-projection of the CA, where they interact with the candidate CA-protein FAP413. FAP42 is a large protein that forms the peripheral ‘beam’ of the C1b-projection, and the FAP246-FAP413 subcomplex serves as the ‘bracket’ between the beam (FAP42) and the C1b ‘pillar’ that attaches the projection to the C1-microtubule. The FAP246-FAP413-FAP42 complex is essential for stable assembly of the C1b, C1f and C2b-projections, and loss of these proteins leads to ciliary motility defects.


2021 ◽  
Author(s):  
Kai Cai ◽  
Yanhe Zhao ◽  
Lei Zhao ◽  
Nhan Phan ◽  
George Witman ◽  
...  

'9+2' motile cilia contain 9 doublet microtubules and a central apparatus (CA) composed of two singlet microtubules with associated projections. The CA plays crucial roles in regulating ciliary motility. Defects in CA assembly or function usually result in motility-impaired or paralyzed cilia, which in humans causes disease. Despite their importance, the protein composition and functions of most CA projections remain largely unknown. Here, we combined genetic approaches and quantitative proteomics with cryo-electron tomography and subtomogram averaging to compare the CA of wild-type Chlamydomonas with those of two CA mutants. Our results show that two conserved proteins, FAP42 and FAP246, are localized to the L-shaped C1b projection of the CA. We also identified another novel CA candidate protein, FAP413, which interacts with both FAP42 and FAP246. FAP42 is a large protein that forms the peripheral 'beam' of the C1b projection, and the FAP246-FAP413 subcomplex serves as the 'bracket' between the beam (FAP42) and the C1b 'pillar' that attaches the projection to the C1 microtubule. The FAP246-FAP413-FAP42 complex is essential for stable assembly of both the C1b and C1f projections, and loss of any of these proteins leads to ciliary motility defects. Our results provide insight into the subunit organization and 3D structure of the C1b projection, suggesting that the FAP246-FAP413-FAP42 subcomplex is part of a large interconnected CA-network that provides mechanical support and may play a role in mechano-signaling between the CA and radial spokes to regulate dynein activity and ciliary beating.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ewa Joachimiak ◽  
Anna Osinka ◽  
Hanan Farahat ◽  
Bianka Świderska ◽  
Ewa Sitkiewicz ◽  
...  

AbstractMotile cilia are ultrastructurally complex cell organelles with the ability to actively move. The highly conserved central apparatus of motile 9 × 2 + 2 cilia is composed of two microtubules and several large microtubule-bound projections, including the C1b/C1f supercomplex. The composition and function of C1b/C1f subunits has only recently started to emerge. We show that in the model ciliate Tetrahymena thermophila, C1b/C1f contains several evolutionarily conserved proteins: Spef2A, Cfap69, Cfap246/LRGUK, Adgb/androglobin, and a ciliate-specific protein Tt170/TTHERM_00205170. Deletion of genes encoding either Spef2A or Cfap69 led to a loss of the entire C1b projection and resulted in an abnormal vortex motion of cilia. Loss of either Cfap246 or Adgb caused only minor alterations in ciliary motility. Comparative analyses of wild-type and C1b-deficient mutant ciliomes revealed that the levels of subunits forming the adjacent C2b projection but not C1d projection are greatly reduced, indicating that C1b stabilizes C2b. Moreover, the levels of several IFT and BBS proteins, HSP70, and enzymes that catalyze the final steps of the glycolytic pathway: enolase ENO1 and pyruvate kinase PYK1, are also reduced in the C1b-less mutants.


2021 ◽  
Author(s):  
Yuqing Hou ◽  
Lei Zhao ◽  
Tomohiro Kubo ◽  
Xi Cheng ◽  
Nathan McNeill ◽  
...  

Cilia are essential organelles required for cell signaling and motility. Nearly all motile cilia have a “9+2” axoneme composed of 9 outer doublet microtubules plus 2 central microtubules; the central microtubules together with their projections is termed the central apparatus (CA). In Chlamydomonas reinhardtii, a model organism for studying cilia, 30 proteins are known CA components, and ∼36 more are predicted to be CA proteins. Among the candidate CA proteins is the highly conserved FAP70, which also has been reported to be associated with the doublet microtubules. Here we determined by super-resolution structured illumination microscopy that FAP70 is located exclusively in the CA, and show by cryo-electron microscopy that its N-terminus is located at the base of the CA's C2a projection. We also found that fap70-1 mutant axonemes lack most of the C2a projection. Mass spectrometry revealed that fap70-1 axonemes lack not only FAP70 but two other conserved candidate CA proteins, FAP65 and FAP147. Finally, FAP65 and FAP147 co-immunoprecipitated with HA-tagged FAP70. Taken together, these data identify FAP70, FAP65, and FAP147 as the first defining components of the C2a projection.


2021 ◽  
Vol 22 (6) ◽  
pp. 3013
Author(s):  
Zuzanna Samsel ◽  
Justyna Sekretarska ◽  
Anna Osinka ◽  
Dorota Wloga ◽  
Ewa Joachimiak

Motile cilia and homologous organelles, the flagella, are an early evolutionarily invention, enabling primitive eukaryotic cells to survive and reproduce. In animals, cilia have undergone functional and structural speciation giving raise to typical motile cilia, motile nodal cilia, and sensory immotile cilia. In contrast to other cilia types, typical motile cilia are able to beat in complex, two-phase movements. Moreover, they contain many additional structures, including central apparatus, composed of two single microtubules connected by a bridge-like structure and assembling numerous complexes called projections. A growing body of evidence supports the important role of the central apparatus in the generation and regulation of the motile cilia movement. Here we review data concerning the central apparatus structure, protein composition, and the significance of its components in ciliary beating regulation.


PLoS Genetics ◽  
2021 ◽  
Vol 17 (3) ◽  
pp. e1009388
Author(s):  
Rafał Bazan ◽  
Adam Schröfel ◽  
Ewa Joachimiak ◽  
Martyna Poprzeczko ◽  
Gaia Pigino ◽  
...  

Ciliary beating requires the coordinated activity of numerous axonemal complexes. The protein composition and role of radial spokes (RS), nexin links (N-DRC) and dyneins (ODAs and IDAs) is well established. However, how information is transmitted from the central apparatus to the RS and across other ciliary structures remains unclear. Here, we identify a complex comprising the evolutionarily conserved proteins Ccdc96 and Ccdc113, positioned parallel to N-DRC and forming a connection between RS3, dynein g, and N-DRC. Although Ccdc96 and Ccdc113 can be transported to cilia independently, their stable docking and function requires the presence of both proteins. Deletion of either CCDC113 or CCDC96 alters cilia beating frequency, amplitude and waveform. We propose that the Ccdc113/Ccdc96 complex transmits signals from RS3 and N-DRC to dynein g and thus regulates its activity and the ciliary beat pattern.


2020 ◽  
pp. 104-111
Author(s):  
E.V. Namrueva

The article analyzes the problems of communicative interaction between the internal affairs bodies and the media. Since their appearance in the structure of government bodies in the late 1980s, press centers and press services have provided information support for specific events and long-term interaction with media representatives. These divisions (both at the federal and regional levels) have become a link between government authorities and the media and begun to play an important role in the state information space. By order of the Ministry of Internal Affairs of the USSR No. 0162 of June 10, 1983, a press bureau was created in the structure of the central apparatus of the department, that was responsible for the information policy of the department. In the regional departments political divisions were formed, which included press services as a structural unit. The work of an inspector responsible for interaction with the media and informing the public was aimed at promoting legal knowledge, as well as creating a positive image of employees of the internal affairs bodies. Modern public relations in the internal affairs department is a management activity that involves interaction, organized using public relations technologies, with a mandatory feedback channel.


Author(s):  
Xiaofei Li ◽  
Daogong Zhang ◽  
Lei Xu ◽  
Yuechen Han ◽  
Wenwen Liu ◽  
...  

Spag6 encodes an axoneme central apparatus protein that is required for normal flagellar and cilia motility. Recent findings suggest that Spag6 also plays a role in ciliogenesis, orientation of cilia basal feet, and planar polarity. Sensory cells of the inner ear display unique structural features that underlie their mechanosensitivity. They represent a distinctive form of cellular polarity, known as planar cell polarity (PCP). However, a role for Spag6 in the inner ear has not yet been explored. In the present study, the function of Spag6 in the inner ear was examined using Spag6-deficient mice. Our results demonstrate hearing loss in the Spag6 mutants, associated with abnormalities in cellular patterning, cell shape, stereocilia bundles and basal bodies, as well as abnormally distributed Frizzled class receptor 6 (FZD6), suggesting that Spag6 participates in PCP regulation. Moreover, we found that the sub-apical microtubule meshwork was disrupted. Our observations suggest new functions for Spag6 in hearing and PCP in the inner ear.


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