Microtubular Dysfunction and Male Infertility

Identification of a Novel Microtubule-Binding Protein in Giardia lamblia

Giardia lamblia is a protozoan that causes diarrheal diseases in humans. Cytoskeletal structures of Giardia trophozoites must be finely reorganized during cell division. To identify Giardia proteins which interact with microtubules (MTs), Giardia lysates were incubated with in vitro-polymerized MTs and then precipitated by ultracentifugation. A hypothetical protein (GL50803_8405) was identified in the precipitated fraction with polymerized MTs and was named GlMBP1 (G. lamblia microtubule-binding protein 1). Interaction of GlMBP1 with MTs was confirmed by MT binding assays using recombinant GlMBP1 (rGlMBP1). In vivo expression of GlMBP1 was shown by a real-time PCR and western blot analysis using anti-rGlMBP1 antibodies. Transgenic G. lamblia trophozoites were constructed by integrating a chimeric gene encoding hemagglutinin (HA)-tagged GlMBP1 into a Giardia chromosome. Immunofluorescence assays of this transgenic G. lamblia, using anti-HA antibodies, revealed that GlMBP1 mainly localized at the basal bodies, axonemes, and median bodies of G. lamblia trophozoites. This result indicates that GlMBP1 is a component of the G. lamblia cytoskeleton.

Diagnosis of primary ciliary dyskinesia / Diagnóstico de discinesia ciliar primária

Primary ciliary dyskinesia (PCD) is a genetic disorder of ciliary structure or function. It results in mucus accumulation and bacterial colonization of the respiratory tract which leads to chronic upper and lower airway infections, organ laterality defects, and fertility problems. We review the respiratory signs and symptoms of PCD, as well as the screening tests for and diagnostic investigation of the disease, together with details related to ciliary function, ciliary ultrastructure, and genetic studies. In addition, we describe the difficulties in diagnosing PCD by means of transmission electron microscopy, as well as describing patient follow-up procedures.

Discinesia ciliar primária (DCP) é uma doença genética que compromete a estrutura e/ou a função ciliar, causando retenção de muco e bactérias no trato respiratório e levando a infecções crônicas nas vias aéreas superiores e inferiores, defeitos de lateralidade visceral e problemas de fertilidade. Revisamos os sinais e sintomas respiratórios da DCP, os testes de triagem e a investigação diagnóstica, bem como detalhes relacionados ao estudo da função, ultraestrutura e genética ciliar. Descrevemos também as dificuldades em diagnosticar a DCP por meio de microscopia eletrônica de transmissão, bem como o seguimento dos pacientes.

Structural analysis of flagellar axonemes from inner arm dynein knockdown strains of Trypanosoma brucei

Trypanosoma brucei is a protozoan flagellate that causes African sleeping sickness. Flagellar function in this organism is critical for life cycle progression and pathogenesis, however the regulation of flagellar motility is not well understood. The flagellar axoneme produces a complex beat through the precisely coordinated firing of many proteins, including multiple dynein motors. These motors are found in the inner arm and outer arm complexes. We are studying one of the inner arm dynein motors in the T. brucei flagellum: dynein-f. RNAi knockdown of genes for two components of dynein-f: DNAH10, the a heavy chain, and IC138, an intermediate chain, cause severe motility defects including immotility. To determine if motility defects result from structural disruption of the axoneme, we used two different flagellar preparations to carefully examine axoneme structure in these strains using transmission electron microscopy (TEM). Our analysis showed that inner arm dynein size, axoneme structural integrity and fixed central pair orientation are not significantly different in either knockdown culture when compared to control cultures. These results support the idea that immotility in knockdowns affecting DNAH10 or IC138 results from loss of dynein-f function rather than from obvious structural defects in the axoneme.

Ciliopathy with special emphasis on kartageners syndrome

Cilia are hair-like structures extending from the cell membrane, perform diverse biological functions. Primary defects in the structure and function of sensory and motile cilia result in multiple ciliopathies. The most prominent genetic abnormality involving motile cilia is primary ciliary dyskinesia [PCD] or Kartageners syndrome. PCD is a rare, usually autosomal recessive, genetically heterogeneous disorder characterized by sino-pulmonary disease, laterality defects and male infertility. One of the important components of cilia is the Dynein. Ciliary ultrastructural defects are identified in approximately 90% of PCD patients and involve the outer dynein arms, inner dynein arms, or both. Diagnosing PCD is challenging and requires a compatible clinical phenotype together with tests such as ciliary ultrastructural analysis, immunofluorescent staining, ciliary beat assessment, and/or nasal nitric oxide measurements. Increased understanding of the pathogenesis will aid in better diagnosis and treatment of PCD. The aim of the article is to present the basic defect involved in the etiology of this interesting syndrome

A Study on Ciliogenesis of Tracheal Epithelium in Human Fetus / 대한해부학회지

Ciliogenesis was investigated in the tracheal epithelium of human fetus at mid trimester of gestation (15~22 weeks), and the substructure of basal body was studied with serial, cross sections. The ciliogenic cells were long columnar cells with an electron -lucent cytoplasm, and contained rich free ribosomes and smooth endoplasmic reticulum. Apical cytoplasm of these cells contained various structures related to ciliogenesis including fibrous granules, procentrioles, centrioles and basal bodies. Basal bodies were located near apical plasma membrane and had basal foot and striated rootlets. In cross section, alar sheets appeared at transitional area between distal portion of basal body and axoneme, and basal foot at distal portion of basal body. Alar sheets arouse from each peripheral triplets of basal body and projected radially clockwise in apex to base view. Basal foot was a cone shaped structure with cross striation which base attached to two or three of the peripheral triplet sets and apex converged to basal foot cap. Three dimentional reconstruction by serial cross section of the basal body showed a structural relationship of alar sheets and basal feet with basal body. By immunohistochemistry, alpha -tubulin label was seen in both basal and surface ciliated cells, and gamma-tubulin label was seen in the apical region of surface cilated cells. These results indicate that ciliogenesis of tracheal epithelium of human fetus is performed mainly by acentriolar ciliogenesis, and suggest the ciliogenesis and ciliary movement at mid trimester of gestation are active.

A Case of Primary Ciliary Dyskinesia due to Radial Spokes Deficiency / 대한이비인후과학회지

Primary ciliary dyskinesia encompasses a heterogenous group of inherited condition characterized by clinical, functional, and ultrastructural features. The transmission electronmicroscopic findings of nasal cilia in a 14-year old girl with primary ciliary dyskinesia were studied. The ultrastructure of axonemes showed normal outer membrane, dynein arms, microtubules, and nexin links but partial lack of radial spokes. The nature of the defective spoke is not clear and further studies will be necessary to determine how the radial spokes and central sheath interact and coordinate ciliary movement.

A Case of Kartagener's Syndrome Presenting as Respiratory and Right Heart Failures / 결핵

Kartagener's syndrome, a congenital disease transmitted as an autosomal recessive illness with a prevalence of approximately 1:20,000 persons, is characterized by the triple association of situs inversus, bronchiectasis, and sinusitis. Affected persons have an incoordination of ciliary motility that leads to defective mucociliary transport, chronic bronchial infections. Kartagener's syndrome is a subset of the immotile cilia syndrome and therefore all patients with Kartagener's syndrome have immotile cilia with obvious ultrastructural defects in the ciliary axoneme. In the respiratory tract this inability presumably causes impaired clearance of mucus and inhaled particles and results in the chronic infections of the sinuses and bronchial trees that are characterized of the disease. The end-stage phenomenon in Kartagener's syndrome, respiratory or heart failure is a less common event and heart-lung transplantation is becoming an accepted therapy for patients with end-stage pulmonary disease in Kartagener's syndrome in many institutes. We report one case of Kartagener's syndrome in a 25-year-old young woman who was presented as respiratory and right heart failures, with review of literatures.