Polychromophilus murinus: a malarial parasite of bats: life-history and ultrastructural studies

Parasitology ◽  
1988 ◽  
Vol 96 (3) ◽  
pp. 591-605 ◽  
Author(s):  
R. A. Gardner ◽  
D. H. Molyneux
Keyword(s):  
Electron Microscopy ◽  
Life History ◽  
Salivary Gland ◽  
Epithelial Cells ◽  
Basement Membrane ◽  
Ultrastructural Study ◽  
Malaria Parasite ◽  
Malarial Parasite ◽  
Malaria Parasites ◽  
Ultrastructural Studies

SUMMARYPolychromophilus murinus, a malaria parasite of Chiroptera is reported from Myotis daubentoni in England. The vector was suspected to be the ectoparasitic Nycteribiid fly, Nycteribia kolenatii. N. kolenatii collected from wild-caught M. daubentoni were found to have oocysts on the midgut and sporozoites in the salivary glands. Wild-caught N. kolenatii were maintained on two wild-caught M. daubentoni harbouring heavy (patent) infections of P. murinus; both oocysts and sporozoites were found in these flies. The mature oocysts measured 52–71 μm in diameter. Sporozoites were straight or slightly crescentic and had a mean length of 7·4 μm. Electron microscopy of immature and mature oocysts revealed a morphology similar to that of malaria parasites. Sporozoites were also similar in structure to Plasmodium sporozoites and were found in the epithelial cells of the salivary gland and within the lumen; a cytostome was present and transverse sections revealed 21 microtubules arranged evenly around the periphery. Sporozoites were observed within the basement membrane of the salivary gland of N. kolenatii; such sporozoites appeared to be penetrating the gland, a process hitherto not described in malaria parasites. Rickettsia-like bodies were found within the cytoplasm of the epithelial cells of the salivary gland. Exflagellation of microgametocytes was achieved. An ultrastructural study of the gametocytes revealed a structure similar to that described in other Haemoproteidae. A common feature of infected erythrocytes was a projecting erythrocyte membrane. Attempts to find schizogony in impression smears and sections of tissues of two infected M. daubentoni were not successful.

Adenomatoid Tumor of the Testis, A Mesonephric Hamartoma

1971 ◽  
Vol 29 ◽  
pp. 318-319
Author(s):  
Raoul Fresco ◽  
Mary Chang-Lo
Keyword(s):  
Electron Microscopy ◽  
Epithelial Cells ◽  
Fibrous Tissue ◽  
Salient Feature ◽  
Luminal Surface ◽  
Adenomatoid Tumor ◽  
Ultrastructural Studies ◽  
Epithelial Origin ◽  
Brush Borders ◽  
Cell Processes

Confusion surrounds the nature of the “adenomatoid tumor” of the testis, as evidenced by the large number of synonyms which have been ascribed to it. Various authors have considered the tumor to be of endothelial, mesothelial or epithelial origin. There appears to be no controversy as to the stromal elements of the tumor, which consists mainly of smooth muscle and fibrous tissue. It is the irregular gland-like spaces which have given rise to the numerous theories as to its histogenesis, and even recent ultrastructural studies fail to agree on the origin of these structures.Electron microscopy of a typical intrascrotal adenomatoid tumor showed the gland-like spaces to be lined by epithelial cells (Fig. 1), rich in cytoplasmic tonofibrils and united to each other by numerous desmosomes (Fig. 2). The most salient feature of these epithelial cells was the presence on their luminal surface of numerous long and repeatedly branching microvillous structures of the type known as stereocilia (Fig. 3). These are extremely long slender cell processes which are as much as three to four times the length of those in brush borders.

THE LIFE CYCLE AND ULTRASTRUCTURE OF MALAMEBA LOCUSTAE (KING AND TAYLOR) (AMOEBIDAE) IN THE MIGRATORY GRASSHOPPER MELANOPLUS SANGUINIPES (F.) (ACRIDIDAE),

1988 ◽  
Vol 120 (8-9) ◽  
pp. 759-772 ◽  
Author(s):  
Lorraine Braun ◽  
Al B. Ewen ◽  
Cedric Gillott
Keyword(s):  
Life History ◽  
Life Cycle ◽  
Epithelial Cells ◽  
Basement Membrane ◽  
Cyst Wall ◽  
Malpighian Tubules ◽  
Midgut Epithelium ◽  
Melanoplus Sanguinipes ◽  
Post Feeding ◽  
Wall Deposition

AbstractThe life history and ultrastructure of the protozoan Malameba locustae (King and Taylor) were studied in the migratory grasshopper Melanoplus sanguinipes (F.) using feeding and injection studies. Insects fed cysts developed infection in the Malpighian tubules 5–6 days later; no trophozoites were observed in haemolymph samples taken 2–20 days post-feeding. After excystment, a few trophozoites entered the midgut epithelium and many were located near the basement membrane of the epithelial cells, where they appeared to degenerate. Trophozoites were not seen to divide in the midgut epithelium, and apparently did not damage this tissue. Trophozoites injected directly into the haemocoel could not be recovered even 4 h after injection, and the Malpighian tubules did not become infected. It was concluded that trophozoites did not penetrate the midgut to enter the haemocoel or move through the haemocoel to infect the Malpighian tubules, but instead probably entered the tubules directly from the gut. Trophozoite ultrastructure in midgut and Malpighian tubules, and cyst wall deposition were described.

Ultrastructure of cultured endometrial epithelial cells grown on two extracellular matrices

1987 ◽  
Vol 45 ◽  
pp. 960-961
Author(s):  
J. Weidmann ◽  
M. Freund ◽  
B. McGeever
Keyword(s):  
Electron Microscopy ◽  
Epithelial Cells ◽  
Basement Membrane ◽  
Collaborative Research ◽  
Extracellular Matrices ◽  
Transmission Electron ◽  
Culture Surface ◽  
In Vivo Growth ◽  
Endometrial Epithelial Cells

Extracellular matrices (EMSA) have been used in tissue culture to mimic the in vivo growth of cells. ECMS have been made by investigators using collagen extraction procedures and now are commercially available either in pre-coated labware or as a liquid which can be poured to variable depths over the culture surface. Common constituents in all are the basement membrane collagens, laminin, and other minor proteoglycans. Cells grown on these matrices are thought to attach at a greater rate, have increased longevity, and mimic the in vivo characteristics. Endometrial epithelial cells were cultured on two commercially available ECMS and examined by transmission electron microscopy to see if any differences in morphology existed.Endometrial epithelial cells derived from menstrual blood were cultured in 25 cm2 polystyrene flasks pre-coated with Matrix ECM (Invitro International) and also Basement Membrane Matrigel (Collaborative Research).

scholarly journals Severe Abnormalities of Lens Epithelial Cells in Exfoliation Syndrome: A Transmission Electron Microscopy Study of Patients with Age-Related Cataract

Medicina ◽  
2019 ◽  
Vol 55 (6) ◽  
pp. 235 ◽  
Author(s):  
Konstantina Ν. Sorkou ◽  
Maria Eleni Manthou ◽  
Soultana Meditskou ◽  
Nikolaos Ziakas ◽  
Konstantinos T. Tsaousis ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Epithelial Cells ◽  
Basement Membrane ◽  
Transmission Electron Microscope ◽  
Lens Epithelial Cells ◽  
Exfoliation Syndrome ◽  
Uvb Radiation ◽  
Age Related ◽  
Transmission Electron

Background and objectives: The aim of this study was to examine via electron microscopy the lens epithelial cells in age-related cataracts and compare the findings between patients with and without exfoliation syndrome, in the Greek population. Materials and Methods: Twenty-one patients with age-related cataracts, older than 60 years, were included in the study. Eleven of them also suffered from exfoliation syndrome. Anterior lens capsules, obtained during phacoemulsification, were examined with a transmission electron microscope. Results: In all cases, ultrastructural features of diffuse intracellular and extracellular oedema were noticed to a varying degree and transparent vacuoles were detected. Often, there was more than one layer of cells, giving the impression that healthier cells tried to cover neighboring cells presenting extensive damage. Commonly, cells lost their regular shape and appeared with expanded nuclei carrying dense granules. Apoptotic cells were also detected. The epithelial cells frequently were completely destroyed or absent, exhibiting loose connections amongst them or with the basement membrane. In exfoliation syndrome (XFS) patients the alterations were more severe. Additionally, the lens epithelial cells (LECs) apical cell membrane appeared with varying distances from the basement membrane, due to different cell “heights”, creating an irregular margin of the epithelium (p < 0.05). Conclusion: Transmission electron microscope (TEM) examination revealed ultrastructural abnormalities in all patients’ lens epithelia, more extended and more frequently observed in XFS group. In all cases, the lesions were comparable to those described in severe pathologies, all of which were excluded from the study. Environmental factors such as increased ultraviolet B (UVB) radiation exposure in Mediterranean countries, genetic factors, epigenetic factors, or all of them, could contribute to these alterations. Further epidemiological and molecular biology research is needed, so as to justify these results.

Ultrastructural studies on chromatin digestion by micrococcal nuclease in the presence of polyamines

1981 ◽  
Vol 48 (1) ◽  
pp. 171-179
Author(s):  
C. Rowlatt ◽  
G.J. Smith
Keyword(s):  
Electron Microscopy ◽  
Salivary Gland ◽  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Micrococcal Nuclease ◽  
Submandibular Salivary Gland ◽  
C57bl Mouse ◽  
Ultrastructural Studies ◽  
Micrococcal Nuclease Digestion ◽  
Nuclease Digestion

Nuclei purified from C57BL mouse submandibular salivary gland were treated with a range of micrococcal nuclease concentrations and times of treatment (from 0.5 unit for 2.5 min to 50 units for 30 min) in the presence of polyamines. About 50% of the chromatin was solubilized initially but with prolonged digestion this chromatin became insoluble again. Electron microscopy showed destruction of the finely dispersed chromatin with mild digestion, followed by aggregation of chromatin with more vigorous digestion. The early disappearance of finely dispersed chromatin filaments was not accompanied by preferential solubilization of chromatin associated with RNA polymerase II (euchromatin). These data suggest that the polyamines markedly reduce the susceptibility of euchromatin to micrococcal nuclease digestion.

scholarly journals AN ULTRASTRUCTURAL STUDY OF GLOMERULAR PERMEABILITY IN AMINONUCLEOSIDE NEPHROSIS USING CATALASE AS A TRACER PROTEIN

1970 ◽  
Vol 132 (6) ◽  
pp. 1168-1180 ◽  
Author(s):  
M. A. Venkatachalam ◽  
R. S. Cotran ◽  
M. J. Karnovsky
Keyword(s):  
Epithelial Cells ◽  
Basement Membrane ◽  
Ultrastructural Study ◽  
Glomerular Permeability ◽  
Beef Liver ◽  
Ultrastructural Cytochemistry ◽  
Slit Pore ◽  
Slit Pores ◽  
Urinary Space ◽  
Aminonucleoside Nephrosis

Beef liver catalase (mol wt 240,000) was injected intravenously into normal rats and rats made nephrotic with aminonucleoside of puromycin. The localization of the tracer in the kidneys was then studied by ultrastructural cytochemistry, 3 min–12 hr after injection. Passage of catalase into the urinary space in normal rats was restricted by the basement membrane and by the epithelial slit pore. Nephrotic glomeruli showed extensive fusion of foot processes and formation of pockets and vacuoles in the fused epithelium; within 3 min after injection, catalase appeared in basal pockets, epithelial vacuoles, and the urinary space. Residual slit pores and close junctions in fused epithelium were impermeable to catalase. These studies indicate that alteration of the epithelial cells and basement membrane is responsible for protein leakage in aminonucleoside nephrosis.

scholarly journals The polyphyly of Plasmodium : comprehensive phylogenetic analyses of the malaria parasites (order Haemosporida) reveal widespread taxonomic conflict

2018 ◽  
Vol 5 (5) ◽  
pp. 171780 ◽  
Author(s):  
Spencer C. Galen ◽  
Janus Borner ◽  
Ellen S. Martinsen ◽  
Juliane Schaer ◽  
Christopher C. Austin ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
Life History ◽  
Base Composition ◽  
Malaria Parasite ◽  
Sequence Data ◽  
Phylogenetic Analyses ◽  
Life History Evolution ◽  
Life History Strategies ◽  
Evolutionary Relationships ◽  
Malaria Parasites

The evolutionary relationships among the apicomplexan blood pathogens known as the malaria parasites (order Haemosporida), some of which infect nearly 200 million humans each year, has remained a vexing phylogenetic problem due to limitations in taxon sampling, character sampling and the extreme nucleotide base composition biases that are characteristic of this clade. Previous phylogenetic work on the malaria parasites has often lacked sufficient representation of the broad taxonomic diversity within the Haemosporida or the multi-locus sequence data needed to resolve deep evolutionary relationships, rendering our understanding of haemosporidian life-history evolution and the origin of the human malaria parasites incomplete. Here we present the most comprehensive phylogenetic analysis of the malaria parasites conducted to date, using samples from a broad diversity of vertebrate hosts that includes numerous enigmatic and poorly known haemosporidian lineages in addition to genome-wide multi-locus sequence data. We find that if base composition differences were corrected for during phylogenetic analysis, we recovered a well-supported topology indicating that the evolutionary history of the malaria parasites was characterized by a complex series of transitions in life-history strategies and host usage. Notably we find that Plasmodium , the malaria parasite genus that includes the species of human medical concern, is polyphyletic with the life-history traits characteristic of this genus having evolved in a dynamic manner across the phylogeny. We find support for multiple instances of gain and loss of asexual proliferation in host blood cells and production of haemozoin pigment, two traits that have been used for taxonomic classification as well as considered to be important factors for parasite virulence and used as drug targets. Lastly, our analysis illustrates the need for a widespread reassessment of malaria parasite taxonomy.

scholarly journals AN ULTRASTRUCTURAL STUDY OF EARLY MORPHOGENETIC EVENTS DURING THE ESTABLISHMENT OF FETAL HEPATIC ERYTHROPOIESIS

1969 ◽  
Vol 40 (2) ◽  
pp. 343-365 ◽  
Author(s):  
Richard A. Rifkind ◽  
David Chui ◽  
Hazel Epler
Keyword(s):  
Epithelial Cell ◽  
Epithelial Cells ◽  
Basement Membrane ◽  
Ultrastructural Study ◽  
Cell Types ◽  
Erythroid Cells ◽  
Intimate Contact ◽  
Definitive Erythropoiesis ◽  
Heterologous Cell ◽  
Vascular Compartment

Morphogenetic events are described which characterize early stages of the interaction between mesenchyme and expanding epithelial cell cords derived from the hepatic endodermal diverticulum in the C57BL/6J mouse. This interaction culminates in the differentiation of hepatic epithelial and hematopoietic tissues. No basement membrane separates the presumptive hepatic epithelial cells from the adjacent mesenchyme, while intercellular attachments, both adherent junctions and desmosomes, are established transiently between heterologous cell types across this epithelio-mesenchymal interface. Yolk sac-derived erythroblasts found in the primitive liver are distinguished morphologically from endogenous hepatic erythroid cells; they are confined to the vascular compartment and are not, apparently, precursors for hepatic erythropoiesis. The earliest recognizable endogenous hepatic hematopoietic cells appear, extravascularly, among those mesenchymal cells in intimate contact with the endodermal epithelium between the 10¼ and 10½ gestational day. Definitive erythropoiesis commences between the 10½ and 11th fetal days. The ultrastructure of these primitive hepatic erythroid cells (proerythroblasts) and their transition to more mature forms (basophilic and polychromatophilic erythroblasts) are described.

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