Development of the lateral palatal brush in larvae of Aedes aegypti (L.) (Diptera: Culicidae)

1990 ◽  
Vol 68 (7) ◽  
pp. 1454-1467 ◽  
Author(s):  
K. M. Fry ◽  
S. B. McIver
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Golgi Apparatus ◽  
Aedes Aegypti ◽  
Rough Endoplasmic Reticulum ◽  
Light And Electron Microscopy ◽  
Fourth Instar ◽  
Muscle Fibres ◽  
Final Length

Light and electron microscopy were used to observe development of the lateral palatal brush in Aedes aegypti (L.) larvae. Development was sampled at 4-h intervals from second- to third-instar ecdyses. Immediately after second-instar ecdysis, the epidermis apolyses from newly deposited cuticle in the lateral palatal pennicular area to form an extensive extracellular cavity into which the fourth-instar lateral palatal brush filaments grow as cytoplasmic extensions. On reaching their final length, the filaments deposit cuticulin, inner epicuticle, and procuticle sequentially on their outer surfaces. The lateral palatal crossbars, on which the lateral palatal brush filaments insert, form after filament development is complete. At the beginning of development, the organelles involved in plasma membrane and cuticle production are located at the base and middle of the cells. As the filament rudiments grow, most rough endoplasmic reticulum, mitochondria, and Golgi apparatus move to the apex of the epidermal cells and into the filament rudiments. After formation of the lateral palatal brush filaments and lateral palatal crossbars, extensive organelle breakdown occurs. Lateral palatal brush formation is unusual in that no digestion and resorption of old endocuticle occurs prior to deposition of new cuticle. No mucopolysaccharide secretion by the lateral palatal brush epidermis was observed, nor were muscle fibres observed to attach to the lateral palatal crossbars, as has been suggested by other workers.

Formation of chlamydospores in Gilbertella persicaria

1981 ◽  
Vol 59 (5) ◽  
pp. 908-928 ◽  
Author(s):  
Martha J. Powell ◽  
Charles E. Bracker ◽  
David J. Sternshein
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Acid Phosphatase ◽  
Light And Electron Microscopy ◽  
Multivesicular Bodies ◽  
Marker Enzyme ◽  
Transparent Layer ◽  
Thiamine Pyrophosphatase ◽  
Gilbertella Persicaria

The cytological events involved in the transformation of vegetative hyphae of the zygomycete Gilbertella persicaria (Eddy) Hesseltine into chlamydospores were studied with light and electron microscopy. Thirty hours after sporangiospores were inoculated into YPG broth, swellings appeared along the aseptate hyphae. Later, septa, traversed by plasmodesmata, delimited each end of the hyphal swellings and compartmentalized these hyphal regions as they differentiated into chlamydospores. Nonswollen regions adjacent to chlamydospores remained as isthmuses. Two additional wall layers appeared within the vegetative wall of the developing chlamydospores. An alveolate, electron-dense wall formed first, and then an electron-transparent layer containing concentrically oriented fibers formed between this layer and the plasma membrane. Rather than a mere condensation of cytoplasm, development and maturation of the multinucleate chlamydospores involved extensive cytoplasmic changes such as an increase in reserve products, lipid and glycogen, an increase and then disappearance of vacuoles, and the breakdown of many mitochondria. Underlying the plasma membrane during chlamydospore wall formation were endoplasmic reticulum, multivesicular bodies, vesicles with fibrillar contents, vesicles with electron-transparent contents, and cisternal rings containing the Golgi apparatus marker enzyme, thiamine pyrophosphatase. Acid phosphatase activity was localized cytochemically in a cisterna which enclosed mitochondria and in vacuoles which contained membrane fragments. Tightly packed membrane whorls and single membrane bounded sacs with finely granular matrices surrounding vacuoles were unique during chlamydospore development. Microbodies were rare in the mature chlamydospore, but endoplasmic reticulum was closely associated with lipid globules. As chlamydospores developed, the cytoplasm in the isthmus became highly vacuolated, lipid globules were closely associated with vacuoles, mitochondria were broken down in vacuoles, unusual membrane configurations appeared, and eventually the membranes degenerated. Unlike chlamydospores, walls of the isthmus did not thicken, but irregularly shaped appositions containing numerous channels formed at intervals on the inside of these walls. The pattern of cytoplasmic transformations during chlamydospore development is similar to events leading to the formation of zygospores and sporangiospores.

scholarly journals Cytochemical demonstration of extraperoxisomal catalase. I. Sheep liver.

1976 ◽  
Vol 24 (6) ◽  
pp. 713-724 ◽  
Author(s):  
F Roels
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Golgi Apparatus ◽  
Rough Endoplasmic Reticulum ◽  
Catalase Activity ◽  
Nonparenchymal Cells ◽  
Sheep Liver ◽  
Heat Stable ◽  
Cytochemical Demonstration ◽  
Electron Microscopes

In sheep hepatocytes catalase activity was demonstrated both within peroxisomes and within the cytosol. In the cytosol the catalase reaction product is contiguous to the plasma membrane and surrounds the nuclei, rough endoplasmic reticulum, cisternae, mitochondria and Golgi apparatus. This is the first cytochemical demonstration of guine extraperoxisomal catalase. No catalase reaction product was seen in the cytosol of nonparenchymal cells. To demonstrate catalase, both glutaraldehyde and formaldehyde fixation were used, followed by a diaminobenzidine technique modified from Novikoff and Goldfischer. Control reactions were performed to distinguish catalase reaction product from adsorption of oxidized diaminobenzidine and from precipitate due to oxidase-, peroxidase- or heat-stable peroxidatic activities. The results were evaluated in the light and electron microscopes.

The structure of the antennal heart of Aedes aegypti (Linnaeus)

1997 ◽  
Vol 75 (3) ◽  
pp. 444-458 ◽  
Author(s):  
B. D. Sun ◽  
J. M. Schmidt
Keyword(s):  
Electron Microscopy ◽  
Connective Tissue ◽  
Aedes Aegypti ◽  
Light And Electron Microscopy ◽  
Single Layer ◽  
Epidermal Cells ◽  
Muscle Fibres ◽  
Columnar Cells

The structure of the antennal heart of Aedes aegypti (L.) (Diptera: Culicidae) was observed using light and electron microscopy. The antennal heart consists of several distinct regions including a single layer of columnar cells, the chamber walls, the valve, the z-body, the muscle fibres, and the connective tissue filaments. The columnar cells are structurally similar to secretory and osmoregulatory cells. Features of tendinous epidermal cells typically involved in the attachment of muscles to the cuticle can be observed in various areas of the antennal heart when it is examined as a whole. A model describing the pumping mechanism of the antennal heart in A. aegypti is presented.

P3502Transmission electron microscopy reveals ultrastructural differences between reticulated and non-reticulated human platelets

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
L Hille ◽  
T Nuehrenberg ◽  
M Lenz ◽  
A Vlachos ◽  
D Trenk
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Golgi Apparatus ◽  
Rough Endoplasmic Reticulum ◽  
Human Platelets ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Dense Granules ◽  
Increased Risk

Abstract Reticulated platelets (RP) are the youngest circulating platelets in blood. Compared to older platelets, RP represent a highly active prothrombotic platelet population associated with an increased risk for cardiovascular events, mortality and impaired response to antiplatelet drugs compared to older platelets (non-RP). The underlying mechanisms for these characteristics of RP are so far poorly understood. This study aimed to characterize ultrastructural properties of RP and non-RP by transmission electron microscopy (TEM) of FACS-sorted human platelets using a novel staining method for RP. Washed platelets from three healthy donors were stained by SYTO™13, a nucleic acid binding fluorescent dye, which enables determination of RP and non-RP based on their RNA-content. 8×106 platelets were fixed, sorted and sandwiched between two layers of agarose gel. Samples were further processed for visualization by TEM. In total, 1047 platelets, i.e., electron micrographs of individual cross-sections, were analysed by an investigator blinded concerning experimental condition. Sizes, numbers of α-granules, dense granules, mitochondria and open canalicular system openings were assessed in RP and non-RP, respectively. Furthermore, platelets were screened for pseudopodia formation as an indicator for activation. Cross-sectional area was significantly different between RP and non-RP (2.44 [1.80–3.22] vs. 1.34 [1.04–1.89] μm2; p<0.0001; median with IQR). α-granule and mitochondria amounts were higher in RP which persisted even after adjustment for platelet size (α-granules: 4.64 [3.46–5.86]/μm2 vs. 4.15 [2.87–5.26]/μm2; p<0.0001; mitochondria: 0.33±0.02 /μm2 vs. 0.12±0.01/μm2; mean ± SEM). In contrast, the amount of open canalicular system openings per square μm was higher in the non-RP group (5.82 [4.34–7.68] /μm2 vs. 5.52 [4.01–7.11] /μm2; p=0.009). Dense granule content per square μm was similar in both RP and non-RP. Pseudopodia were present in 38% (RP) respective 37% (non-RP) of platelets. Notably, golgi apparatus and rough endoplasmic reticulum which are rarely seen in platelets were detected in several RP. Analysis of TEM pictures revealed an almost 2-fold higher cross-sectional area in RP compared to non-RP. Even after adjustment for differences in size, α-granule content remained significantly higher in RP indicating a higher storage pool for prothrombotic constituents like p-selectin or von Willebrand factor. Although the relative amount of dense granules per area did not differ between the two groups, a higher absolute number of dense granules per platelet in the RP group is indicative for higher amounts of stored small molecules such as ADP, calcium or serotonin. Despite the anucleate nature of platelets, the presence of golgi apparatus and rough endoplasmic reticulum suggests the capability of protein biosynthesis in RP. These comprehensive findings provide new important insight into the ultrastructural properties of human RP. Acknowledgement/Funding PharmCompNet Baden-Württemberg: Kompetenznetzwerk Pharmakologie Baden-Württemberg

scholarly journals Effect of microtubule assembly status on the intracellular processing and surface expression of an integral protein of the plasma membrane.

1984 ◽  
Vol 99 (3) ◽  
pp. 1101-1109 ◽  
Author(s):  
A A Rogalski ◽  
J E Bergmann ◽  
S J Singer
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Golgi Apparatus ◽  
G Protein ◽  
Rough Endoplasmic Reticulum ◽  
Intracellular Transport ◽  
Temperature Shift ◽  
Surface Expression ◽  
Microtubule Assembly ◽  
In Cells

We studied the effects of changes in microtubule assembly status upon the intracellular transport of an integral membrane protein from the rough endoplasmic reticulum to the plasma membrane. The protein was the G glycoprotein of vesicular stomatitis virus in cells infected with the Orsay-45 temperature-sensitive mutant of the virus; the synchronous intracellular transport of the G protein could be initiated by a temperature shift-down protocol. The intracellular and surface-expressed G protein were separately detected and localized in the same cells at different times after the temperature shift, by double-immunofluorescence microscopic measurements, and the extent of sialylation of the G protein at different times was quantitated by immunoprecipitation and SDS PAGE of [35S]methionine-labeled cell extracts. Neither complete disassembly of the cytoplasmic microtubules by nocodazole treatment, nor the radical reorganization of microtubules upon taxol treatment, led to any perceptible changes in the rate or extent of G protein sialylation, nor to any marked changes in the rate or extent of surface appearance of the G protein. However, whereas in control cells the surface expression of G was polarized, at membrane regions in juxtaposition to the perinuclear compact Golgi apparatus, in cells with disassembled microtubules the surface expression of the G protein was uniform, corresponding to the intracellular dispersal of the elements of the Golgi apparatus. The mechanisms of transfer of integral proteins from the rough endoplasmic reticulum to the Golgi apparatus, and from the Golgi apparatus to the plasma membrane, are discussed in the light of these observations, and compared with earlier studies of the intracellular transport of secretory proteins.

scholarly journals Canine Cutaneous Histiocytoma A Light and Electron Microscopic Study

1970 ◽  
Vol 7 (1) ◽  
pp. 12-27 ◽  
Author(s):  
D. F. Kelly
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Acid Phosphatase ◽  
Microscopic Study ◽  
Mononuclear Cell ◽  
Electron Microscopic Study ◽  
Light And Electron Microscopy ◽  
Perinuclear Region ◽  
Electron Microscopic

Cutaneous histiocytomas from 4 dogs were examined by light and electron microscopy. A large (up to 10 μ in diameter) mononuclear cell with prominent filiform processes of the plasma membrane predominated. Its cytoplasm contained relatively small amounts of endoplasmic reticulum and mitochondria, only occasional lysosomes, fibrils, most obvious in the perinuclear region, and small amounts of cytoplasmic debris. Acid phosphatase was not detected. Fibroblasts and collagen formed a small part of the lesion, except at the junction with surrounding dermis, where fibers were plentiful. The morphologic features of the lesion are compatible with the suggestion that the predominant cell is of histiocytic type.

scholarly journals Disruption of the Golgi Apparatus and Contribution of the Endoplasmic Reticulum to the SARS-CoV-2 Replication Complex

Viruses ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1798
Author(s):  
Ted Hackstadt ◽  
Abhilash I. Chiramel ◽  
Forrest H. Hoyt ◽  
Brandi N. Williamson ◽  
Cheryl A. Dooley ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Golgi Apparatus ◽  
Rna Synthesis ◽  
Light And Electron Microscopy ◽  
Brefeldin A ◽  
Viral Proteins ◽  
Protein Markers ◽  
Replication Complex ◽  
Golgi Fragmentation

A variety of immunolabeling procedures for both light and electron microscopy were used to examine the cellular origins of the host membranes supporting the SARS-CoV-2 replication complex. The endoplasmic reticulum has long been implicated as a source of membrane for the coronavirus replication organelle. Using dsRNA as a marker for sites of viral RNA synthesis, we provide additional evidence supporting ER as a prominent source of membrane. In addition, we observed a rapid fragmentation of the Golgi apparatus which is visible by 6 h and complete by 12 h post-infection. Golgi derived lipid appears to be incorporated into the replication organelle although protein markers are dispersed throughout the infected cell. The mechanism of Golgi disruption is undefined, but chemical disruption of the Golgi apparatus by brefeldin A is inhibitory to viral replication. A search for an individual SARS-CoV-2 protein responsible for this activity identified at least five viral proteins, M, S, E, Orf6, and nsp3, that induced Golgi fragmentation when expressed in eukaryotic cells. Each of these proteins, as well as nsp4, also caused visible changes to ER structure as shown by correlative light and electron microscopy (CLEM). Collectively, these results imply that specific disruption of the Golgi apparatus is a critical component of coronavirus replication.

Membranous Structures Directly Come in Contact With p62/SQSTM1 Bodies

2021 ◽  
pp. 002215542110114
Author(s):  
Isei Tanida ◽  
Tomohiro Haruta ◽  
Mitsuo Suga ◽  
Shunsuke Takei ◽  
Akira Takebe ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Click Chemistry ◽  
Rough Endoplasmic Reticulum ◽  
Unique Feature ◽  
Light And Electron Microscopy ◽  
Adaptor Protein

During autophagy, autophagosomes are formed to engulf cytoplasmic contents. p62/SQSTM-1 is an autophagic adaptor protein that forms p62 bodies. A unique feature of p62 bodies is that they seem to directly associate with membranous structures. We first investigated the co-localization of mKate2-p62 bodies with phospholipids using click chemistry with propargyl-choline. Propargyl-choline-labeled phospholipids were detected inside the mKate2-p62 bodies, suggesting that phospholipids were present inside the bodies. To clarify whether or not p62 bodies come in contact with membranous structures directly, we investigated the ultrastructures of p62 bodies using in-resin correlative light and electron microscopy of the Epon-embedded cells expressing mKate2-p62. Fluorescent-positive p62 bodies were detected as uniformly lightly osmificated structures by electron microscopy. Membranous structures were detected on and inside the p62 bodies. In addition, multimembranous structures with rough endoplasmic reticulum–like structures that resembled autophagosomes directly came in contact with amorphous-shaped p62 bodies. These results suggested that p62 bodies are unique structures that can come in contact with membranous structures directly:

scholarly journals Progressive Depletion of Rough Endoplasmic Reticulum in Epithelial Cells of the Small Intestine in Monosodium Glutamate Mice Model of Obesity

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Kazuhiko Nakadate ◽  
Kento Motojima ◽  
Tomoya Hirakawa ◽  
Sawako Tanaka-Nakadate
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Small Intestine ◽  
Epithelial Cells ◽  
Rough Endoplasmic Reticulum ◽  
Defense Mechanism ◽  
Monosodium Glutamate ◽  
Light And Electron Microscopy ◽  
Obese Mice ◽  
Pathological Changes

Chronic obesity is a known risk factor for metabolic syndrome. However, little is known about pathological changes in the small intestine associated with chronic obesity. This study investigated cellular and subcellular level changes in the small intestine of obese mice. In this study, a mouse model of obesity was established by early postnatal administration of monosodium glutamate. Changes in body weight were monitored, and pathological changes in the small intestine were evaluated using hematoxylin-eosin and Nissl staining and light and electron microscopy. Consequently, obese mice were significantly heavier compared with controls from 9 weeks of age. Villi in the small intestine of obese mice were elongated and thinned. There was reduced hematoxylin staining in the epithelium of the small intestine of obese mice. Electron microscopy revealed a significant decrease in and shortening of rough endoplasmic reticulum in epithelial cells of the small intestine of obese mice compared with normal mice. The decrease in rough endoplasmic reticulum in the small intestine epithelial cells of obese mice indicates that obesity starting in childhood influences various functions of the small intestine, such as protein synthesis, and could impair both the defense mechanism against invasion of pathogenic microbes and nutritional absorption.

Morphology and ontogeny of tannin-producing structures in two tropical legume trees

Botany ◽  
2014 ◽  
Vol 92 (7) ◽  
pp. 513-521 ◽  
Author(s):  
Thais Cury de Barros ◽  
Simone Pádua Teixeira
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Rough Endoplasmic Reticulum ◽  
Light And Electron Microscopy ◽  
Stages Of Development ◽  
Tropical Legume ◽  
Legume Trees ◽  
Vegetative Buds ◽  
Tannin Cells

Two legume trees largely known as tannin producers — Dimorphandra mollis Benth. (Caesalpinioideae) and Stryphnodendron adstringens (Mart.) Coville (Mimosoideae) — were used as models to elucidate the morphology and ontogeny of tannin cells. Vegetative parts of plants were processed for observation using light and electron microscopy (scanning and transmission). Idioblasts, found even in young plants of both species, and secretory trichomes, observed in vegetative buds of mature plants of S. adstringens, are responsible for tannin production. The tanniniferous idioblasts originate from protoderm and also from ground meristem cells. The ground meristem proved to be the best place to study the development of tanniniferous idioblasts at different stages of development, which allowed us to monitor the production and accumulation of tannins in the same tissue. Our data indicate that there is a relationship between the production of tannins and the process of vacuolation of tanniniferous cells. The results also indicate the probable performance of rough endoplasmic reticulum (RER) and plastids in the production of tannins.

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