scholarly journals The Morphology, Ultrastructure and Molecular Phylogeny of a New Freshwater Heterolobose Amoeba Parafumarolamoeba stagnalis n. sp. (Vahlkampfiidae; Heterolobosea)

Diversity ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 433
Author(s):  
Anastasia Borodina ◽  
Alexander Mylnikov ◽  
Jan Janouškovec ◽  
Patrick Keeling ◽  
Denis Tikhonenkov
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Light And Electron Microscopy ◽  
Soil Microbial Communities ◽  
Single Species ◽  
Evolutionary Relationships ◽  
Ssu Rrna ◽  
Soil Microbial ◽  
Taxonomic Description ◽  
Fine Morphology

Heterolobose amoebae are important members of marine, freshwater, and soil microbial communities, but their diversity remains under-explored. We studied the diversity of Vahlkampfiidae to improve our understanding of heterolobosean relationships and their representation in aquatic benthos. Using light and electron microscopy, and molecular phylogenies based on the SSU rRNA and ITS loci, we describe the fine morphology and evolutionary relationships of a new heterolobosean Parafumarolamoeba stagnalis n. sp. from a small pond in European Russia. Cells of P. stagnalis possess a clearly distinguishable anterior hyaline pseudopodium, eruptive movement, several thin and sometimes branched uroidal filaments, spherical cysts without pores and plugs, and mitochondria that have discoid cristae and are surrounded by cisternae of the endoplasmic reticulum. The genus Parafumarolamoeba has so far included a single species, Parafumarolamoeba alta from high-altitude soil in Tibet, which is morphologically distinct from P. stagnalis. Taxonomic description for a new Parafumarolamoeba species is therefore provided.

Phase-contrast and electron-microscopic observations on a membranous complex in primary spermatocytes of the mouse

1975 ◽  
Vol 18 (1) ◽  
pp. 1-17
Author(s):  
A. Pleshkewych ◽  
L. Levine
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Phase Contrast ◽  
Cultured Cells ◽  
Light And Electron Microscopy ◽  
Cytoplasmic Inclusion ◽  
Electron Microscopic ◽  
Secondary Spermatocyte ◽  
Living Mouse ◽  
Circular Contour

A prominent cytoplasmic inclusion present in living mouse primary spermatocytes has been observed by both light and electron microscopy. It began to form at prometaphase and continued to increase in thickness and length as the cells developed. By metaphase it was a distinct sausage-shaped boundary that enclosed a portion of the cytoplasm between the spindle and the cell membrane. At the end of metaphase, the inclusion reached its maximum length. At telophase, it was divided between the daughter secondaries. The inclusion persisted as a circular contour in the interphase secondary spermatocyte. Electron microscopy of the same cultured cells that were previously observed with light microscopy revealed that the inclusion was a distinctive formation of membranes. It consisted of agranular cisternae and vesicles, and was therefore a membranous complex. Many of the smaller vesicles in the membranous complex resembled those found in the spindle. The cisternae in the membranous complex were identical to the cisternal endoplasmic reticulum of interphase primary spermatocytes. Nevertheless, the organization of vesicles and cisternae into the membranous complex was unique for the primaries in division stages, since such an organization was not present in their interphase stages.

Anatomy of the Unpollinated and Pollinated Watermelon Stigma

1982 ◽  
Vol 54 (1) ◽  
pp. 341-355
Author(s):  
M. SEDGLEY
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Light And Electron Microscopy ◽  
Freeze Fracture ◽  
Pollen Grain ◽  
Acidic Polysaccharides ◽  
Before And After ◽  
Em Autoradiography ◽  
Pollen Grain Wall ◽  
Stigma Secretion

The structure of the watermelon stigma before and after pollination was studied using light and electron microscopy, freeze-fracture and autoradiography. The wall thickenings of the papilla transfer cells contained callose and their presence prior to pollination was confirmed using EM-autoradiography, freeze-fracture and fixation. No further callose thickenings were produced following pollination. Pollination resulted in a rapid increase in aqueous stigma secretion and localized disruption of the cuticle, which appeared to remain on the surface of the secretion. Autolysis of the papilla cells, which had commenced prior to pollination, was accelerated and appeared to take place via cup-shaped vacuoles developed from distended endoplasmic reticulum. The reaction was localized to the papilla cells adjacent to the pollen tube only. Both pollen-grain wall and stigma secretion contained proteins, carbohydrates, acidic polysaccharides, lipids and phenolics.

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 LOCALIZATION OF PEROXIDASE ACTIVITY IN MICROBODIES OF FETAL MOUSE LIVER

1969 ◽  
Vol 17 (7) ◽  
pp. 454-466 ◽  
Author(s):  
EDWARD ESSNER
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Acid Phosphatase ◽  
Peroxidase Activity ◽  
Mouse Liver ◽  
Fetal Liver ◽  
Light And Electron Microscopy ◽  
Small Population ◽  
Fetal Mouse ◽  
Fetal Mouse Liver

The peroxidase activity of microbodies in fetal mouse liver was studied by light and electron microscopy. Two types of microbodies were present; a small population of bodies that lacked a nucleoid, predominant on the 16th day of gestation, and a larger population of nucleoid-bearing microbodies, predominant on the 19th day, in association with the rough endoplasmic reticulum from which they probably originate. Both types of bodies were visualized when incubated for peroxidase activity but were negative (19th day) for acid phosphatase activity. The findings suggest that the anucleoid- and nucleoid-bearing organelles together constitute the microbody population of the fetal liver.

Conidiogenesis in Termitaria snyderi (Fungi Imperfecti)

1973 ◽  
Vol 51 (12) ◽  
pp. 2307-2314 ◽  
Author(s):  
Saeed R. Khan ◽  
Henry C. Aldrich
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Lipid Droplets ◽  
Light And Electron Microscopy ◽  
Cross Wall ◽  
Transverse Septum ◽  
Conidiogenous Locus ◽  
Oriented Parallel ◽  
Fungi Imperfecti

Termitaria snyderi Thaxter forms small discoid lesions on the exoskeleton of different species of termites. Its conidiogenesis has been studied by light and electron microscopy. The phialides are oriented parallel in a closely packed sporodochium. The conidia are produced endogenously in basipetal succession from a fixed conidiogenous locus and are liberated when the tip is broken off the phialide as a result of the force applied by the formation of new conidia. The area of the phialide beyond the locus forms a tubular collarette. The conidium initial buds out at the locus and after it has received its organelles and reached a certain size it is delimited by a centripetally growing transverse septum. The region of the growing septum has many vesicles which may be involved in cross wall synthesis. Conidia are cylindrical, uninucleate, and double-walled. They have mitochondria, endoplasmic reticulum (ER), conspicuous lipid droplets, and vacuoles. Each conidiophore has long mitochondria, elongate nuclei, and much endoplasmic reticulum. The plasmalemma of the conidiophore is highly convoluted.

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.

Protoplasmic changes during stomatal development in Funaria

1983 ◽  
Vol 61 (10) ◽  
pp. 2515-2526 ◽  
Author(s):  
Fred D. Sack ◽  
D. J. Paolillo Jr.
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Electron Density ◽  
Pore Formation ◽  
Light And Electron Microscopy ◽  
Polar Regions ◽  
Lipid Bodies ◽  
Stomatal Development ◽  
Funaria Hygrometrica ◽  
Parallel Arrays

Key protoplasmic features of stomatal development in Funaria hygrometrica Hedw. (Musci) were characterized using light and electron microscopy. Endoplasmic reticulum (ER) cisternae are initially rough and often arranged in parallel arrays. During pore formation, the cytoplasm becomes packed with tubular, smooth ER. Older but still functional stomata contain small amounts of primarily cisternal ER. Lipid bodies decrease in electron density when tubular ER appears. Preliminary observations indicate that two large vacuoles occupy the polar regions of open, but not closed, stomata. Intact plasmodesmata occur in developing but not mature walls. Plastid structure, microtubule distribution, and other protoplasmic features are essentially similar to those described in the stomata of other genera.

scholarly journals A CLEM approach to access to the ultrastructure at the graft interface in Arabidopsis thaliana

2021 ◽  
Author(s):  
Clément Chambaud ◽  
Sarah Jane Cookson ◽  
Nathalie Ollat ◽  
Emmanuelle M. F. Bayer ◽  
Lysiane Brocard
Keyword(s):  
Electron Microscopy ◽  
Arabidopsis Thaliana ◽  
Endoplasmic Reticulum ◽  
Cell Wall ◽  
Light And Electron Microscopy ◽  
Three Dimensional ◽  
Cellular Events ◽  
Membrane Tethering ◽  
Secondary Plasmodesmata ◽  
Graft Interface

Despite recent progress in our understanding of the graft union formation, we still know little about the cellular events underlying the grafting process. This is partially due to the difficulty of reliably targeting the graft interface in electron microscopy to study its ultrastructure and three-dimensional architecture. To overcome this technological bottleneck, we developed a correlative light electron microscopy approach (CLEM) to study the graft interface with high ultrastructural resolution. Grafting hypocotyls of Arabidopsis thaliana lines expressing YFP or mRFP in the endoplasmic reticulum allowed the efficient targeting of the grafting interface for under light and electron microscopy. To explore the potential of our method to study sub-cellular events at the graft interface, we focused on the formation of secondary plasmodesmata (PD) between the grafted partners. We showed that 4 classes of PD were formed at the interface and that PD introgression into the call wall was initiated equally by both partners. Moreover, the success of PD formation appeared not systematic with a third of PD not spanning the cell wall entirely. Characterizing the ultrastructural characteristics of these failed PD gives us insights into the process of secondary PD biogenesis. We showed that the thinning of the cell wall and the endoplasmic reticulum-plasma membrane tethering seem to be required for the establishment of symplastic connections between the scion and the rootstock. The resolution reached in this work shows that our CLEM method offer a new scale to the study for biological processes requiring the combination of light and electron microscopy.

scholarly journals Pan-American Trypanosoma (Megatrypanum) perronei sp. n. in white-tailed deer (Odocoileus virginianus) and its deer ked Lipoptena mazamae: morphological, developmental and phylogeographical characterisation

2019 ◽  
Author(s):  
Herakles Antonio Garcia ◽  
Alexander P. Blanco ◽  
Adriana C. Rodrigues ◽  
Carla M. Rodrigues ◽  
Carmen S. A. Takata ◽  
...  
Keyword(s):  
Odocoileus Virginianus ◽  
North American ◽  
Host Species ◽  
Light And Electron Microscopy ◽  
Single Species ◽  
Fallow Deer ◽  
Molecular Evidence ◽  
Ssu Rrna ◽  
Rdna Sequences ◽  
Deer Ked

Abstract Background: The subgenus Megatrypanum comprises trypanosomes of cervids and bovids from around the world. Here, Odocoileus virginianus (white-tailed deer = WTD) and its ectoparasite, the deer ked Lipoptena mazamae (hippoboscid fly), were surveyed for trypanosomes in Venezuela. Results: Haemoculturing unveiled 20% infected WTD, while 47% (7/15) of blood samples and 38% (11/29) of ked guts tested positive for the Megatrypanum-specific TthCATL-PCR. CATL and SSU rRNA sequences uncovered a single species of trypanosome. Phylogeny based on SSU rRNA and gGAPDH sequences tightly cluster WTD trypanosomes from Venezuela and the USA, which were strongly supported as geographical variants of the herein described Trypanosoma (Megatrypanum) perronei sp. n. In our analyses, T. perronei was closest to T. sp. D30 of fallow deer (Germany), both nested into TthII alongside other trypanosomes of cervids (North American elks and European fallow, red and sika deer), and bovids (cattle, antelopes and sheep). Insights into T. perronei life cycle were obtained from early haemocultures of deer blood and co-culture with mammalian and insect cells showing flagellates resembling Megatrypanum trypanosomes previously reported in deer blood, and deer ked guts. For the first time, a trypanosome from a cervid was cultured and phylogenetically and morphologically (light and electron microscopy) characterised. Conclusions: In the analyses based on SSU rRNA, gGAPDH, CATL and ITS rDNA sequences, neither cervids nor bovids trypanosomes were monophyletic but intertwined within TthI and TthII major phylogenetic lineages. One host species can harbour more than one species/genotype of trypanosomes, but each trypanosome species/genotype was found in a single host species or in phylogenetically related hosts. Molecular evidence that L. mazamae may transmit T. perronei suggests important evolutionary constraints making tight the tripartite T. perronei–WTD–deer ked association. In a plausible evolutionary scenario, T. perronei entered South America with North American WTD at the Pliocene–Pleistocene boundary following the closure of the Panama Isthmus.

scholarly journals Cholinesterase activity of lamellated sensory corpuscles in the rat lip

1986 ◽  
Vol 44 (4) ◽  
pp. 325-333 ◽  
Author(s):  
II-Sei Watanabe ◽  
Chizuka Ide
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Cholinesterase Activity ◽  
Light And Electron Microscopy ◽  
Reaction Products ◽  
Cell Plasma Membrane ◽  
Axon Terminals ◽  
Cell Plasma ◽  
Periaxonal Space ◽  
Lamellar Cell

Non-specific cholinesterase (ChE) activity was demonstrated in lamellated sensory corpuscles of the rat lip by light and electron microscopy using Karnovsky and Root's method. ChE activity was present in the interlamellar spaces between neighbouring lamellae as well as in the periaxonal space between axon terminals and their adjacent lamellae. Reaction products of ChE activity were also deposited in some caveolae of the lamellar cell plasma membrane, and in the cisternae of the rough endoplasmic reticulum as well as in the nuclear envelope of lamellar cell bodies. No definite reaction products were detected within the axon terminals. These findings show that the lamellated corpuscles in the rat lip, like other mechanoreceptors, have an intense ChE activity which is mainly associated with lamellar cells. It can be said that ChE histochemistry is useful to detect mechanoreceptors. The functional significance of ChE in mechanoreceptors is discussed.

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