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PubMed1990

Ultrastructural localization of alpha-L-fucose, factor VIII related antigen and vimentin in endothelial cells of human skin blood vessels using the low temperature embedding technique with Lowicryl K4M.

The present study was performed to investigate the ultrastructural localization of the binding sites of the lectin Ulex europaeus agglutinin, Type I (UEA) and the antibody against factor VIII related antigen (F VIII RAG), both widely used as vascular markers in human skin capillaries at light microscopy level. In addition the ultrastructural localization of vimentin, the major protein of the endothelial intermediate filaments, was demonstrated in human vascular endothelial cells (EC) in situ. The low temperature postembedding technique with Lowicryl K4M with subsequent application of gold labelled antibodies provided both well preserved antigenicity and morphology. The antigenic site of UEA, alpha-L-fucose containing glycohydrate residues, was primarily found in or near the luminal plasma membrane of EC. Gold particles representing the sites of F VII RAG were located in the Weibel-Palade bodies (WPB) of EC. The ultrastructural staining pattern of the anti-vimentin antibody showed an exclusive labelling of the intermediate filaments of EC.

Acrylic Resins↗
PubMed1993

Muscle fibre degeneration in distal myopathy (Welander)--ultrastructure related to immunohistochemical observations on cytoskeletal proteins and Leu-19 antigen.

In seven patients with long-standing and six patients with early symptoms of Welander distal myopathy (WDM), monoclonal antibodies directed against such cytoskeletal proteins as dystrophin, spectrin and desmin and against Leu-19, a myoblast and satellite cell related antigen, were applied to muscle biopsies from the anterior tibial and soleus muscles. In addition, ultrastructural studies were carried out on biopsies from the soleus muscle. In muscle fibres from patients with early symptoms there was normal immunostaining for dystrophin, spectrin, desmin and Leu-19. In the patients with long-standing symptoms, there was also a normal expression of dystrophin, and a normal staining for spectrin and desmin was found in normal sized muscle fibres. Occasionally normal sized muscle fibres showed staining for Leu-19. Increased staining for spectrin and desmin and a strong Leu-19 staining was seen in normal sized muscle fibres with rimmed vacuoles and in atrophic fibres. Increased staining for spectrin, desmin and Leu-19 has been described in denervated muscle fibres and, thus, the present findings may support earlier findings of a neurogenic component in Welander distal myopathy. In the soleus muscle, ultrastructural muscle fibre abnormalities conformed to those in the anterior tibial muscle. Many rimmed vacuoles were observed which corresponded, at the ultrastructural level, to autophagic vacuoles. Intranuclear and cytoplasmic filamentous inclusions of the same shape and diameter as in inclusion body myositis were observed.

Adult↗
PubMed1989

Ultrastructural features of the osteoid of patients with fibrogenesis imperfecta ossium.

The osteoid of a patient with Fibrogenesis Imperfecta Ossium is described. Three iliac crest biopsies were taken; firstly before treatment, secondly after calcitriol therapy and finally after successful treatment with melphalan and prednisolone. In the pretreatment biopsy the osteoid was greatly enlarged, showed complete absence of the birefringence characteristic of oriented collagen fibers, and at ultrastructural level was shown to be composed of abnormal collagen fibrils. The fibrils were often curved and were extremely variable in thickness. Calcification within the osteoid took the form of calcospherites and spread of calcification from these to collagen fibrils was greatly delayed. In the second biopsy two aspects of osteoid ultrastructure were noted; some samples resembled the first biopsy, but others had a different organization. The osteoid of these samples had two regions: an inner region containing abnormal collagen fibrils and an outer region composed of moderately electron-dense amorphous material. The osteoblasts associated with this region were clearly highly biosynthetically active. The third biopsy, after treatment with Melphalan and prednisolone, showed a reversion to more normal bone ultrastructure with uniform, oriented collagen fibrils and prompt mineralization resulting in narrow osteoid seams. Remnants of the original abnormal osteoid were present in the marrow space as calcified debris. Reasons for the success of this therapeutic regime are unclear; however, some speculation is made as to the possible roles of the cytotoxic drug and the glucocorticoid in the regression of this condition.

Biopsy↗
PubMedDate not supplied

Ultrastructural alterations and retention of the C-propeptide of type II collagen in human chondrocytes exposed in vitro to brefeldin A.

Normal human chondrocytes grown in vitro were exposed to 10 micrograms/ml Brefeldin A (BFA) for 24 h, 1 microgram/ml for 4 h, or 0.1 microgram/ml for 4 h and evaluated for ultrastructural alterations. BFA in the amount of 0.1 microgram/ml resulted in vacuolization, disappearance of the Golgi, and moderate increases in rough endoplasmic reticulum (rER) vesicles. After 1 microgram/ml BFA exposure large interconnected cisternae were identified. BFA treatment of 10 micrograms/ml was associated with large dilated ER cisternae which contained material of variable electron densities. Immunocytochemical localization showed markedly increased type II procollagen intracellular retention in BFA-treated cells. High dose BFA-treated cells showed ultrastructural similarities to those seen in the skeletal dysplasia hypochondrogenesis. Results presented here show that in vitro culture of normal human chondrocytes results in retention of the C-propeptide of type II collagen and marked alterations in cytoplasmic ultrastructure.

Brefeldin A↗
PubMedDate not supplied

Ultrastructural investigations of bone resorptive cells in two types of autosomal dominant osteopetrosis.

In order to investigate the ultrastructure of bone resorptive cells in the two types of adult benign human osteopetrosis, iliac crest biopsies were obtained from 11 patients and 10 normal males, who served as a control group. Six patients had the radiological type I (4 women, 2 men, aged 23-58 years, mean = 36.5 years), and 5 type II disease (5 men, aged 20-48 years, mean = 29.8 years). The normal controls (aged 23-48 years, mean 34.1 years) were recruited from the medical staff. The biopsies were immediately divided. From each patients, half was embedded in paraffin for histochemistry and light microscopy, and half in epon for transmission electron microscopy. The osteoclasts were markedly reduced in number and size in Type I disease (0.2 +/- .7 cells vs. 2.9 +/- 1.0 cells per 2.7 mm2 of bone area, p < 0.01) compared to controls, and stained only weakly for tartrate-resistant acid phosphatase (TRAP). At the ultrastructural level, no signs of active bone resorption were identified, whereas numerous mononuclear cells were observed at the bone surfaces. In type II disease, the osteoclasts were large and highly multi-nucleated, with an increased number (8.3 +/- 2.3 cells vs. 2.9 +/- 1.0. cells per 2.7 mm2 of bone area, p < 0.01) compared to controls. In all patients with this type, but never in type I or in the controls, a smooth, TRAP-positive substance was seen between the osteoclasts and the bone surface. Ultrastructurally, this substance was amorphous, with a condensation along the cell membrane.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed2004

Ultrastructural and immunohistochemical similarities of two distinct entities; multiple sclerosis and hereditary motor sensory neuropathy.

In the present study, we present the ultrastructural and immunohistochemical properties of the sural nerves of two patients, one of whom was diagnosed as having multiple sclerosis with involvement of the peripheral nervous system (PNS), and the other as having hereditary motor sensory neuropathy type-I with involvement of the central nervous system (CNS). Expression of several extracellular matrix (ECM) proteins (fibronectin, laminin, and collagen type-IV), intermediate filaments (vimentin) and S-100 protein (marker for the axon-Schwann cell interface) was investigated by means of immunohistochemical methods. In addition, the tissue samples were evaluated ultrastructurally. Immunohistochemical staining revealed increased expression of the ECM molecules mentioned above in relation with the sural nerves of the patients. We hypothesize that this enhanced expression is due to Schwann cell-axon interactions. Vimentin expression was different in Schwann cells and S-100 immunostaining was decreased near the Schwann cell-axon interface. Myelin fragmentation, axon vacuolization, onion bulbs, tomoculous formation, axonal degeneration were found to occur. These results suggest that there is active ECM reorganization in the sural nerve of these patients, and some ultrastructural changes are similar in the damaged axonal organization and in Schwann cells although the changes are not completely the same in the two patients. In conclusion, our study demonstrates that there is an association between the demyelinization process in the CNS and the PNS even though they are affected by different mechanisms.

Adult↗
PubMed2005

Ultrastructural and immunohistochemical analysis of rat uroepithelial cell junctions after partial bladder outlet obstruction and selective COX-2 inhibitor treatment.

The present study was undertaken to evaluate alterations in uroepithelial cell junctional complexes in partial bladder outlet obstruction (PBOO) of rat bladders using ultrastructural morphometry and immunohistochemistry, and to determine whether selective COX-2 inhibitors have any effects on these structures. A total of 18 male rats were separated into three groups of six rats each: (1) sham-operated animals served as controls; (2) a PBOO group, without further treatment (3) and a group that immediately after PBOO, received treatment for 4 weeks with oral Celecoxib, a selective COX-2 inhibitor. Uroepithelial cell junctions were evaluated using transmission electron microscopy combined with morphometry. Results were also assessed by E-cadherin and alpha-catenin immunohistochemistry. Morphometrical analysis of ultrastructural evaluations revealed that 4 weeks of PBOO caused a significant reduction in the electron density of zonula adherens and zonula occludens junctional complexes. Moreover, some desmosomes located between the deeper cells of the uroepithelium showed signs of disintegration. Selective COX-2 inhibitor treatment during 4 weeks of PBOO showed protective effects on adherens and occludens junctions, as well as on desmosomes. Immunohistochemical analysis of E-cadherin confirmed that the decreased E-cadherin immunolabelling in 4 weeks of PBOO was prevented by selective COX-2 inhibitor treatment. Based on ultrastructural morphometrical analysis, we conclude that PBOO alone and in combination with selective COX-2 inhibitors can have considerable effects on uroepithelial cellular junctions. Our findings provide a novel area of investigation regarding the selective use of COX-2 inhibitors following PBOO.

Adherens Junctions↗
PubMed2006

Neovaginal mucosa after Vecchietti's laparoscopic operation for Rokitansky syndrome: structural and ultrastructural study.

OBJECTIVE: This study was undertaken to evaluate structural and ultrastructural characteristics of the mucosa of neovaginae created by Vecchietti's laparoscopic operation for Rokitansky syndrome. STUDY DESIGN: Vaginoscopy and Schiller test were performed 3, 6, and 12 months after the operation in 106 patients. A biopsy specimen of the neovagina obtained 12 to 18 months after surgery in 19 patients was examined by light, scanning electron, and transmission electron microscopy. RESULTS: At vaginoscopy, the neovaginal mucosa appeared smooth, lacking the folds that characterize the normal vagina; 12 months after the operation, an iodium-positive epithelium was present in all neovaginae. Mild ultrastructural modifications, as compared with normal vaginal mucosa, were reduced maturation, inflammatory infiltration, and tendency to superficial desquamation. CONCLUSION: At a 12-month follow-up, the mucosa of neovaginae created by the Vecchietti technique is comparable to the normal vaginal mucosa, with mild structural and ultrastructural modifications that we believe might be due to reduced vascularization.

Adolescent↗
PubMed2005

Morphometric and ultrastructural characterization of Bos indicus preantral follicles.

The aim of the present study was to characterize the ultrastructure of zebu cow preantral follicles (PAFs). Ovarian cortex samples were processed for light and transmission electron microscopy. Primordial follicles consisted of an oocyte surrounded by one layer of flattened or flattened-cuboidal granulosa cells. The oocyte contained a large and usually eccentric nucleus. Most organelles were located at the perinuclear ooplasm. Round shaped mitochondria, which contained electron-dense granules, smooth and rough endoplasma reticulum and a Golgi apparatus were also observed. Vesicles and coated pits were often observed in the cortical ooplasm. In primary follicles, the oocyte was surrounded by one layer of cuboidal granulosa cells. Short microvilli were observed on the oolema. Secondary follicles consisted of an oocyte surrounded by a variable number of layers of cuboidal granulosa cells. Small secondary follicles had an ultrastructure very similar to that observed in primary follicles. At this follicular stage, the zona pellucida was beginning to form around the oocyte. In large secondary follicles, the zona pellucida was totally developed around the oocyte. Several granulosa cell projections could be detected that were encroaching into the zona pellucida and protruding towards the oocyte, where gap junctions were observed between oocyte and granulosa cell membranes. Organelles within the oocyte were located at the periphery of the ooplasm, and clusters of cortical granules were observed. Round mitochondria were abundant in all developmental stages. In conclusion, this study described the ultrastructure of zebu cow PAFs, and some unique characteristics could be observed as compared with what has been reported for follicles of Bos taurus cattle.

Animals↗
PubMed2005

Histological and ultrastructural analysis of cryopreserved sheep preantral follicles.

The aim of this study was to verify the histological and ultrastructural characteristics of sheep preantral follicles after exposure of ovarian tissue to cryopreservation in glycerol (GLY), ethylene glycol (EG), propanediol (PROH) or dimethyl sulfoxide (DMSO) in order to determine the optimum method to store sheep ovarian tissue for later experimental or clinical use. Each ovarian pair from five mixed-breed ewes was divided into 17 fragments. One (control) fragment was immediately fixed for routine histological and ultrastructural studies and the remaining (test) fragments were randomly distributed in cryotubes, equilibrated at 20 degrees C/20 min in 1.8 mL of minimal essential medium (MEM) containing 1.5 or 3 M GLY, EG, PROH or DMSO and then either fixed for morphological studies to determine their possible toxic effect or frozen/thawed and then fixed to test the effect of cryopreservation on preantral follicles. Histological analysis showed that, compared to control fragments, all cryoprotectants at both concentrations significantly reduced the percentage of normal preantral follicles in ovarian fragments prior to or after cryopreservation. PROH 3.0 M appeared to exert a more toxic effect (P<0.05) than the other cryoprotectants in noncryopreserved tissues. After freezing/thawing, the highest (P<0.05) percentages of lightmicroscopical normal preantral follicles were observed in ovarian fragments cryopreserved in EG (1.5 and 3 M) or DMSO (1.5 M). However, transmission electronic microscopical (TEM) examination showed that only the DMSO-cryopreserved preantral follicles had normal ultrastructure. The data suggest that sheep preantral follicles should be cryopreserved with 1.5 M DMSO for later clinical or experimental application.

Animals↗
PubMed2005

Ultrastructural study of calculus-enamel and calculus-root interfaces.

UNLABELLED: The attachment of dental calculus to the tooth (enamel or cementum) surface affects the ease or difficulty of its removal. Understanding the ultrastructural features of the calculus-tooth interface will help in the development of efficient strategies for efficient removal of dental calculus. OBJECTIVE: The aim of this study was to determine the ultrastructural characteristics of the calculus-tooth interface in relation to the occurrence of calculus fracture. DESIGN: Investigation of the ultrastructural characteristics of the calculus-tooth interface was made on eight human molars with mature supragingival and subgingival calculus using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and fourier transform infra-red (FT-IR) spectroscopy. RESULTS: Fractures were shown by SEM to consistently occur within the calculus itself, but not at the calculus-tooth interface. Higher magnification revealed that the enamel apatite crystals (in the case of supragingival calculus) or the cementum apatite crystals (in the case of subgingival calculus) appeared intimately connected with the calculus crystals at the calculus-enamel or calculus-cementum interface. TEM micrographs confirmed this intimate direct connection or fusion (epitaxial growth) of calculus crystals with enamel and cementum apatite crystals. FT-IR showed lower concentrations of organic phase attributed to microorganisms and higher concentrations of collagen at the calculus-cementum interface compared to that in the calculus away from the interface. CONCLUSION: Difficulty in complete calculus removal from tooth surfaces (especially from cementum or dentin) may be due in part to the intimate contact between the calculus and the tooth, due to the chemical bonding between the calculus crystals and the tooth apatite crystals and occasional fusion (i.e., epitaxial growth) of the calculus calcium phosphate crystals with the enamel, dentin or apatite crystals. This cohesive bonding results in fracture planes occurring within the calculus instead of at the calculus-tooth interface.

Apatites↗
PubMed2006

Study on the effects of mechanical pressure to the ultrastructure and secretion ability of mandibular condylar chondrocytes.

During mandibular movement, condyle is subjected to repetitive compression and the mandibular condylar chondrocytes (MCCs) can detect and respond to this biomechanical environment by altering their metabolism. The present study was undertaken to investigate the effects of pressure to the ultrastructure, aggrecan synthesis, nitric oxide (NO) and prostaglandin F(1)alpha(PGF(1)alpha) secretion in MCCs. In vitro cultured rabbit MCCs were incubated and pressed under continuous pressure of 90kPa for 60min and 360min by hydraulic pressure controlled cellular strain unit. The ultrastructure, aggrecan mRNA expression, activity of nitric oxide synthase (NOS) and PGF(1)alpha secretion were investigated. Besides, nitric oxide inhibitor was used together with pressure to investigate the role of NO in mechanical effects. The appearance of MCC on TEM showed that after been pressed under 90kPa for 60min, the cellular processes became elongated and voluminous, together with aggrecan mRNA increasing. Under 90kPa for 360min, some of the cells showed distinct sign of apotosis and the aggrecan mRNA decreased. Pressure of 90kPa could cause increase of NOS activity and decrease of PGF(1)alpha composition. Inhibitor experiments indicated that pressure-induced upregulation of aggrecan mRNA and inhibition of PGF(1)alpha synthesis was partly mediated by NO. Continuous pressure could cause changes on the ultrastructure and function of MCC, as well as up-regulation of aggrecan synthesis, increase of NO secretion and decrease of PGF(1)alpha composition. NO was the upstream molecule, which mediated the response of aggrecan and PGF(1)alpha to mechanical pressure.

Animals↗
PubMed2004

Ultrastructural changes in pneumocyte type II cells following traumatic brain injury in rats.

OBJECTIVE: We aimed to demonstrate the time-dependent ultrastructural changes in pneumocyte type II cells following brain injury, and to propose an electron microscopic scoring model for the damage. METHODS: Forty Wistar-Albino female rats weighing 170-200 g were used. The rats were allocated into five groups. The first group was the control and the second was the craniotomy without trauma. The others were trauma groups. Weight-drop method was used for achieving head trauma. Samples were obtained from the right and left pulmonary lobes at 2-, 8-, and 24-h intervals after transcardiac perfusion. An electron microscopic scoring model was used to reveal the changes. RESULTS: There were no ultrastructural pathological findings pointing to lung injury in any rat of the control groups. There was intense intracellular oedema in type II pneumocyte and interstitial oedema in the adjacent tissue in trauma groups. Oedema in mitochondria and dilatation in both smooth endoplasmic reticulum and Golgi apparatus was more evident in the 8- and 24-h trauma groups. The chromatin dispersion was disintegrated in the nucleus in all trauma groups. Scores of all trauma groups were significantly different from the controls (P<0.05). All trauma groups were different from each other at significant levels (P<0.05 for each trauma groups). CONCLUSIONS: The data suggested that ultrastructural damage is obvious at 2 h and deteriorates with time. The electron microscopic scoring model worked well in depicting the traumatic changes, which were supported by lipid peroxidation. Further experiments are needed to determine the exact outcome after brain death model.

Animals↗
PubMed2006

Aberrant expression of apoptosis proteins and ultrastructural aberrations in uterine leiomyomas from patients with hereditary leiomyomatosis and renal cell carcinoma.

OBJECTIVE: To examine differences between sporadic and familial uterine leiomyomata related to expression of apoptosis-related proteins and tumor ultrastructure. DESIGN: Expression of apoptosis-related proteins was measured by immunohistochemistry. Tumor ultrastructure was evaluated by transmission electron microscopy. SETTING: Human genetics laboratory. PATIENT(S): Patients confirmed for hereditary leiomyomatosis and renal cell carcinoma (HLRCC), and anonymous archival sporadic leiomyoma patients. INTERVENTION(S): Samples for electron microscopy were collected from myomectomy and hysterectomy with informed consent. Other samples were archival. MAIN OUTCOME MEASURE(S): Intensity of immunohistochemistry staining and evaluation of electron micrographs. RESULT(S): Immunohistochemistry revealed increases in expression of antiapoptotic Bcl-2 and the proliferation factor proliferating cell nuclear antigen (PCNA) in both sporadic and HLRCC uterine leiomyomata. Furthermore, we observed an increase in antiapoptotic Bcl-x and a concurrent decrease in proapoptotic Bak solely in HLRCC leiomyomas. We also observed ultrastructural alterations in HLRCC and sporadic leiomyomas, particularly pertaining to extracellular matrix and intermediate filament aggregation. CONCLUSION(S): The observed alterations in expression of apoptosis-related proteins indicate a shift in both HLRCC and sporadic leiomyomas to increased resistance to apoptosis compared with myometrium, which appears to be stronger in HLRCC leiomyomas. The changes observed in HLRCC leiomyomas appear to be related to activation of the hypoxia pathways. The results suggest not only a partial overlap in the pathogenic mechanism of the two tumor types, but also intriguing differences.

Apoptosis Regulatory Proteins↗
PubMed2004

Cell proliferation and ultrastructural changes of the duodenal mucosa of patients affected by familial adenomatous polyposis.

Patients affected by familial adenomatous polyposis (FAP) are at risk of developing duodenal neoplasia. Our objective was to detect early abnormalities of the epithelial cell proliferation and ultrastructure of apparently normal duodenal mucosa of FAP patients. Biopsy specimens were taken from the duodenal mucosa. Cell proliferation was studied by immunohistochemistry with proliferating cell nuclear antigen (PCNA), and ultrastructure, by transmission electron microscopy. We found that the PCNA labeling index for duodenal mucosa of patients with FAP was higher in comparison to the case of hospital controls without cancer risk (P = 0.019). Moreover, ultrastructural changes related to an impairment of cell adhesion function were found in all biopsies of FAP patients but not in the duodenal mucosa of the controls. We conclude that alterations of cell proliferation kinetics and epithelial adherens junction structures were phenotypic characteristics of histologically normal duodenal mucosa of FAP patients. These abnormalities may be considered as intermediate biomarkers of neoplasia and potential surrogate endpoints in chemoprevention studies.

Adenomatous Polyposis Coli↗
PubMed2005

Phytomonas serpens: cysteine peptidase inhibitors interfere with growth, ultrastructure and host adhesion.

In this study, we report the ultrastructural and growth alterations caused by cysteine peptidase inhibitors on the plant trypanosomatid Phytomonas serpens. We showed that the cysteine peptidase inhibitors at 10 microM were able to arrest cellular growth as well as promote alterations in the cell morphology, including the parasites becoming short and round. Additionally, iodoacetamide induced ultrastructural alterations, such as disintegration of cytoplasmic organelles, swelling of the nucleus and kinetoplast-mitochondrion complex, which culminated in parasite death. Leupeptin and antipain induced the appearance of microvillar extensions and blebs on the cytoplasmic membrane, resembling a shedding process. A 40 kDa cysteine peptidase was detected in hydrophobic and hydrophilic phases of P. serpens cells after Triton X-114 extraction. Additionally, we have shown through immunoblotting that anti-cruzipain polyclonal antibodies recognised two major polypeptides in P. serpens, including a 40 kDa component. Flow cytometry analysis confirmed that this cruzipain-like protein has a location on the cell surface. Ultrastructural immunocytochemical analysis demonstrated the presence of the cruzipain-like protein on the surface and in small membrane fragments released from leupeptin-treated parasites. Furthermore, the involvement of cysteine peptidases of P. serpens in the interaction with explanted salivary glands of the phytophagous insect Oncopeltus fasciatus was also investigated. When P. serpens cells were pre-treated with either cysteine peptidase inhibitors or anti-cruzipain antibody, a significant reduction of the interaction process was observed. Collectively, these results suggest that cysteine peptidases participate in several biological processes in P. serpens including cell growth and interaction with the invertebrate vector.

Animals↗
PubMed2005

Ultrastructural analysis supports transferring Nosema whitei Weiser 1953 to the genus Paranosema and creation a new combination, Paranosema whitei.

The current ultrastructural description of Nosema whitei is in agreement with the genus definition of Paranosema [Sokolova, Y.Y., Dolgikh, V.V., Morzhina, E.V., Nassonova, E.S., Issi, I.V., Terry, R.S., Ironside, J.E., Smith, J.E., Vossbrinck, C.R., 2003. Establishment of the new genus Paranosema based on the ultrastructure and molecular phylogeny of the type species Paranosema grylli Gen. Nov., Comb. Nov (Sokolova, Selezniov, Dolgikh, Issi 1994), from the cricket Gryllus bimaculatus Deg. Journal of Invertebrate Pathology 84, 159-172]. In addition to exhibiting similar spore morphology and sporogony type, N. whitei, like P. grylli and Paranosema locustae, possesses a distinct meront-sporont transitional stage in the life cycle; develops in the host fat body, and produces secretory material arranged in "tubular structures" during sporogony. Ultrastructural analysis supports the similarity of N. whitei to P. grylli and to P. locustae as predicted on the basis SSrDNA sequence data (GenBank Accession Nos. AY305323, AY305325, and AY305324). Comparative studies of these three related species provide a good example of the consistency of morphological and sequence data, and support both the placement of N. whitei inside the genus Paranosema and the validity of the new combination Paranosema whitei (Weiser).

Animals↗
PubMed2006

An ultrastructural and molecular study of Tubulinosema kingi Kramer (Microsporidia: Tubulinosematidae) from Drosophila melanogaster (Diptera: Drosophilidae) and its parasitoid Asobara tabida (Hymenoptera: Braconidae).

Tubulinosema kingi is a pathogen of Drosophila spp. that was originally described 40 years ago. Although Drosophila melanogaster is widely used as a model organism for biological research, only limited data about microsporidia infecting Drosophila have been published so far and very little is known about the ultrastructure of T. kingi. In this study, we present the results of ultrastructural and molecular examinations of T. kingi. The whole life cycle took place in direct contact with the host cell cytoplasm and all examined life cycle stages contained a diplokaryon. Very few membrane elements were present in early merogonial stages, but their number and order of arrangement increased as the life cycle proceeded. The cell membrane of meronts had a surface coat of tubular elements that encircled the cell. Later, numerous electron-dense strands without any ornamentation accumulated on the plasma membrane, indicating that cells had entered sporogony. The cell membrane of sporonts was covered by electron-dense material. The polar filament in the spores was slightly anisofilar with the last three or four coils being smaller in diameter. The polar filament has 10 to 14 coils which were arranged predominantly in a single row, but in many spores, one winding of the coiled polar filament was located inside the outer coils. In some spores, the polar filament was irregularly arranged in two or even three rows. Molecular analysis showed that all Tubulinosema spp. are closely related and form a clade of their own that is distinct from the Nosema/Vairimorpha clade. All these ultrastructural and molecular features are in concordance with the family Tubulinosematidae and the genus Tubulinosema which reinforces the recent reclassification of this microsporidium.

Animals↗