Ultrastructural study of the development of the auditory tympana in the cricket Teleogryllus commodus (Walker)

Development ◽  
1978 ◽  
Vol 46 (1) ◽  
pp. 75-87
Author(s):  
E. E. Ball ◽  
A. N. Cowan

The cuticle in the tympanal area of immature crickets, Teleogryllus commodus (Walker), is ultrastructurally indistinguishable from that elsewhere on the prothoracic leg. It is only in the pharate adult that changes associated with development of the tympana first appear. In pharate adults and adults the external layer of the tympana consists of a layer of electrondense material overlying a layer where the electron-dense material is interspersed with cuticle in which the bundles of microfibrils are coarser and more loosely arranged than elsewhere in the leg. The innermost portion of the tympana consists of this same type of cuticle without the electron-dense material. Associated with the appearance of the electron-dense material in the tympana of the pharate adult is a change in the toluidine blue staining properties from blue to deep purple. The reaction of the tympana in acid and base is consistent with their being composed of chitin. There are no major deposits of resilin in the tympana. In the first few days following the imaginal ecdysis the posterior tympanum and underlying trachea come into tight apposition due to the withdrawal of the epidermal cells. The epidermal cells do not withdraw from beneath the anterior tympanum. The surrounding non-tympanal cuticle continues to thicken for several weeks with the result that in the mature adult the posterior tympanum serves as an acoustic window in the thick cuticle of the leg. The functional significance of the anterior tympanum has not been established.


1975 ◽  
Vol 53 (22) ◽  
pp. 2589-2597 ◽  
Author(s):  
H. H. Edwards

M1-a-mediated resistance in barley to invasion by the CR3 race of Erysiphe graminis f. sp. hordei does not occur in every host cell with the same speed and severity. In some cells ultrastructural changes within the host cell as a result of resistance will occur within 24 h after inoculation, whereas in other cells these changes may take up to 72 h. In some cells the ultrastructural changes are so drastic that they give the appearance of a hypersensitive death of the host cell, whereas in other cells the changes are very slight. In any case, at the end of these changes the fungus ceases growth. The ultrastructural changes occur in penetrated host epidermal cells as well as non-infected adjacent epidermal and mesophyll cells.The following ultrastructural changes have been observed: (1) an electron-dense material which occurs either free in the vacuole or adhering to the tonoplast (the material is granular or in large clumps); (2) an increased electron density of the host cytoplasm and nucleus; (3) a breakdown of the tonoplast so that the cytoplasmic constituents become dispersed throughout the cell lumen; and (4) the deposition of papillar-like material in areas other than the penetration site. The first three changes take place within the host cell protoplasts and are directly attributable to the gene M1-a. These changes are typical of stress or incompatibility responses and thus M1-a appears to trigger a generalized incompatibility response in the presence of race CR3. The papillar-like material occurs outside the host cell protoplast in the same manner as the papilla and probably is not directly attributable to M1-a.



1978 ◽  
Vol 56 (17) ◽  
pp. 2097-2108 ◽  
Author(s):  
Verna J. Higgins ◽  
G. L. Lazarovits

As part of a continuing study of non-host resistance, red clover leaves inoculated with the clover pathogen Stemphylium sarcinaeforme, or the closely related alfalfa pathogen S. botryosum, were examined by light and electron microscopy to compare the events occurring in the initial stages of infection. Stemphylium botryosum penetrated leaves primarily via the stomata with resultant death of the guard cells and with varying effects on adjacent epidermal cells. Appressoria were frequently formed, and although they rarely resulted in successful penetrations, the contacted epidermal cells were often markedly affected as judged by toluidine blue staining. Growth of hyphae was intercellular but very limited in its extent. At some infection sites, one to several mesophyll cells underwent extensive plasmolysis and cytoplasmic disruption. Less severely affected mesophyll cells contained large lipid bodies, abundant rough endoplasmic reticulum, and Golgi vesicles and had wall appositions at points of contact with necrotic cells or with hyphae. Stemphylium sarcinaeforme generally penetrated between or directly through the epidermal cells, causing death of the contacted cells. Hyphae grew intercellularly or intracellularly in the palisade tissue and hyphal elongation was considerably more rapid than that of S. botryosum. Palisade cells adjacent to, or containing, the hyphae underwent several different types of cytoplasmic deterioration. Mesophyll cells surrounding these areas showed the same features as comparable cells in tissue infected by S. botryosum. In tissue infected by either fungus, the exterior of host cell walls was coated with a layer of extracellular material.



Author(s):  
J. R. Ruby ◽  
R. F. Dyer ◽  
R. G. Skalko ◽  
R. F. Gasser ◽  
E. P. Volpe

An electron microscope examination of fetal ovaries has revealed that developing germ cells are connected by intercellular bridges. In this investigation several species have been studied including human, mouse, chicken, and tadpole (Rana pipiens). These studies demonstrate that intercellular connections are similar in morphology regardless of the species.Basically, all bridges are characterized by a band of electron-dense material on the cytoplasmic side of the tri-laminar membrane surrounding the connection (Fig.l). This membrane is continuous with the plasma membrane of the conjoined cells. The dense material, however, never extends beyond the limits of the bridge. Variations in the configuration of intercellular connections were noted in all ovaries studied. However, the bridges in each individual species usually exhibits one structural characteristic seldom found in the others. For example, bridges in the human ovary very often have large blebs projecting from the lateral borders whereas the sides of the connections in the mouse gonad merely demonstrate a slight convexity.



2020 ◽  
Vol 64 (4) ◽  
pp. 375-377
Author(s):  
Ekkehard Hewer ◽  
Anja M. Schmitt

Rapid on-site evaluation (ROSE) is one of cytopathology’s “unique selling propositions.” The quality, speed, and ease of handling of the staining used is a critical factor for the efficacy of the ROSE procedure. Here, we describe a modification of rapid toluidine blue staining that can be performed within 25 s, provides excellent nuclear morphology, and is compatible with subsequent Papanicolaou staining of the slides. Furthermore, exposure to hazardous chemicals is minimized, as no organic solvents other than the alcohol-based fixative and glycerin for temporary mounting and coverslipping are required. We have used this protocol successfully in our ROSE practice and have not observed any discrepancies between toluidine blue- and permanent Papanicolaou-stained slides.



2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
Gabriela Elena Lupusoru ◽  
Ioana-Georgiana Ailincai ◽  
Andreea Gabriella Andronesi ◽  
Mircea Lupusoru ◽  
Lavinia Maria Bernea ◽  
...  

Abstract Background and Aims Hantavirus infection is a zoonosis rare in the Balkan Peninsula but with increasing frequency and geographic spread, causing two major syndromes, depending on the viral serotype: hemorrhagic fever with renal syndrome (HFRS) and cardiopulmonary syndrome (CPS). Because there is no specific treatment or vaccine for this condition, the key for minimizing the progression to chronic kidney disease, secondary hypertension or death is early diagnosis and prompt therapy. This paper presents a case of HFSR in which needle kidney biopsy played a major role in diagnosis and draws attention on this zoonosis that might be highly underdiagnosed in Balkan Peninsula. Method A 26-year-old female with no medical history was admitted in our department with acute kidney injury (AKI), nephritic syndrome with nephrotic range proteinuria, high blood pressure, hepatic cytolysis, severe thrombocytopenia, anemia and leukocytosis, elevated LDH, normal haptoglobin, positive Coombs test (Table 1). Immunological testing (C3, C4, ANA, ANCA, antiGBM), viral infection markers (hepatitis B/C, HIV, Epstein-Barr, Cytomegalovirus), IgA/M/G were all negative and ADAMTS13 activity was normal. Abdominal sonography showed both kidneys of normal size and shape. A kidney biopsy was performed. The biopsy specimen showed macroscopic features of hemorrhage in the renal medulla. In immunofluorescence the staining was negative for IgA, IgG, IgM, C1q, C3c, k and λ chains, albumin and fibrinogen. Light microscopy (LM) revealed normal glomeruli and arterioles, dilated proximal tubules with resorption droplets at the apical pole and erythrocytes in the lumen, important interstitial hemorrhage in the medulla, with no inflammation or interstitial fibrosis. The electron microscopy (EM) showed segmental foot process effacement, endotheliosis of the peritubular capillaries, rare plasmocytes and macrophages in the interstitium (Figure 1). The aspect of hemorrhagic interstitial nephritis suggested Hantavirus infection. Serological testing revealed both IgM and IgG antibodies for the Hantaan serotype (HTNV). The final diagnosis was HTNV hemorrhagic interstitial nephritis with intrinsic AKI and secondary hypertension. MO426   Figure 1: A, B LM, Toluidine Blue staining. Normal glomerulus. Resorption droplets in the proximal tubular cells. C, D LM, Toluidine Blue staining. Extensive interstitial hemorrhage in medulla, tubulitis. E EM. Interstitial extravasation of erythrocytes. F EM. Endothelial swelling, foot process effacement. Results The patient was treated with oral methylprednisolone 16mg/d for 2 weeks, with progressive tampering of the dose and removal after 2 months. She received antihypertensive and antiproteinuric treatment with ramipril. The evolution was good, with creatinine and liver enzymes returning to normal. Conclusion HFRS belongs to a group of rare zoonoses in Balkan Peninsula, the most involved serotypes being Dobrava and Puumala. This case had positive serology for HTNV usually being found in China and Russia, but our patient didn’t travel abroad before she got ill, so we can’t consider the case as being an imported infection. That highlights a possible underdiagnosis of the disease in this region and also the need to re-evaluate geographic distribution of different strains and changes in ecological aspects given that they may pose a major risk to public health. The disease begins with flu-like symptoms and progresses to AKI with severe thrombocytopenia, anemia and coagulation disorders, being easily mistaken for haemolytic uremic syndrome. In a region with sporadic cases, we face diagnosis difficulties related especially to the absence of initial diagnosis suspicion, so we emphasize the need to include this pathology in the differential diagnosis algorithm of diseases evolving with thrombocytopenia, anemia, hepatic cytolysis and renal injury.





1985 ◽  
Vol 79 (1) ◽  
pp. 161-179 ◽  
Author(s):  
S.L. Tamm ◽  
S. Tamm

Macrocilia from the lips of the ctenophore Beroe consist of multiple rows of ciliary axonemes surrounded by a common membrane, with a giant capping structure at the tip. The cap is formed by extensions of the A and central-pair microtubules, which are bound together by electron-dense material into a pointed projection about 1.5 micron long. The tip undergoes visible changes in configuration during the beat cycle of macrocilia. In the rest position at the end of the effective stroke (+30 degrees total bend angle), there is no displacement between the tips of the axonemes, and the capping structure points straight into the stomach cavity. In the sigmoid arrest position at the end of the recovery stroke (−60 degrees total bend angle), the tip of the macrocilium is hook-shaped and points toward the stomach in the direction of the subsequent effective stroke. This change in tip configuration is caused by sliding displacement of microtubules that are bound together at their distal ends. Electron microscopy and two-dimensional models show that the singlet microtubule cap acts as if it were hinged to the ends of the axonemes and tilted to absorb the microtubule displacement that occurs during the recovery stroke. The straight and hooked shapes of the tip are thought to help the ctenophore ingest prey.



1984 ◽  
Vol 66 (1) ◽  
pp. 175-187
Author(s):  
M. Fukumoto

The apical structure in Perophora annectens spermatozoa is approximately 4 micron in length and it is helically coiled. Its major component is a striated structure, which may be analogous to a perforatorium. The plasmalemma enclosing the anterior quarter of the apical structure is covered by extracellular materials, the anterior ornaments. During spermiogenesis, the apical structure is first recognized as a small blister of the plasmalemma at the apex of the young spermatid. It develops into a conical protrusion and then into a finger-like process (approximately 1 micron in length). This process is transformed into an elongated process (approximately 4 micron in length) with electron-dense material in its core. Finally, the elongated process is helically coiled to form an apical structure in which electron-dense material forms dense striations. Vesicles (50-70 nm in diameter), presumably derived from the Golgi apparatus, have been recognized in the blisters of younger spermatids, and can be followed through to the finger-like process. In the finger-like process these vesicles are transformed into smaller vesicles (20-30 nm in diameter), which probably fuse with the anterior plasmalemma of the finger-like process. This suggests that chorion lysin(s) is associated with the anterior membrane enclosing the apical structure in these spermatozoa.



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