Studies withBrugia pahangi. 14. Intrauterine development of the microfilaria and a comparison with other filarial species

1976 ◽  
Vol 50 (4) ◽  
pp. 251-257 ◽  
Author(s):  
Rosemary Rogers ◽  
D. S. Ellis ◽  
D. A. Denham
Keyword(s):  
Electron Microscopy ◽  
Light And Electron Microscopy ◽  
Uterine Wall ◽  
Dense Material ◽  
Intrauterine Development ◽  
Brugia Pahangi ◽  
Electron Dense Material ◽  
Large Numbers ◽  
Egg Shells ◽  
Egg Shell

ABSTRACTThe intrauterine development ofBrugia pahangiembryos was followed from after fertilization to birth, using light and electron microscopy. The origin and development of the sheath of the microfilaria and its Possible role in the nutrition of the developing embryo were particularly investigated. Comparisons were drawn with the intrauterine development of other filarial species. The egg shell of theB. pahangiembryo js distinct from the oolemma and forms the sheath of the microfilaria. It is suggested that the electron dense material released by cells of the uterine wall and passing along the channels between the egg shells of adjacent embryos is nutritive. The death of large numbers of developing embryos in the central uterine Jumen is probably caused by overcrowding as their size rapidly increases, leading to nutritional deficiency.

Intrauterine development of the microfilariae of Dipetalonema viteae

1978 ◽  
Vol 52 (1) ◽  
pp. 7-10 ◽  
Author(s):  
D. S. Ellis ◽  
Rosemary Rogers ◽  
A. E. Bianco ◽  
D. A. Denham
Keyword(s):  
Early Stage ◽  
Uterine Wall ◽  
Dense Material ◽  
Intrauterine Development ◽  
Electron Dense Material ◽  
Stage Of Development ◽  
Egg Shell ◽  
Dipetalonema Viteae

ABSTRACTThe egg shell of Dipetalonema viteae separated from the oolemma and became highly convoluted at an early stage of development. No second oolemma or trilaminate membrane was seen. Channels containing electron dense material (thought to be nutrient material from the uterine wall) were formed between adjacent embryos. Many developing embryos died.Microvilli were formed by the uterine wall and developing embryos were closely apposed to these (again presumably to obtain nutrient).Embryos emerged from the egg in the uterus and were born as unsheathed microfilariae.

Role of M Cells and Macrophages in the Entrance of Mycobacterium paratuberculosis into Domes of Ileal Peyer's Patches in Calves

1988 ◽  
Vol 25 (2) ◽  
pp. 131-137 ◽  
Author(s):  
E. Momotani ◽  
D. L. Whipple ◽  
A. B. Thiermann ◽  
N. F. Cheville
Keyword(s):  
Electron Microscopy ◽  
Cross Section ◽  
Light And Electron Microscopy ◽  
Peyer's Patches ◽  
Dense Material ◽  
M Cells ◽  
Mycobacterium Paratuberculosis ◽  
Electron Dense Material ◽  
Acid Fast Bacilli

Ligated ileal loops of calves were inoculated with live and heat-killed Mycobacterium paratuberculosis and were examined by light and electron microscopy. At 5 hours after inoculation, acid-fast bacilli were in subepithelial macrophages, but not in M cells covering domes. At 20 hours, more than 50 acid-fast bacilli per cross section were in subepithelial macrophages in domes. Both living and heat-killed bacilli passed into domes. Addition of anti- M. paratuberculosis bovine scrum to the inoculum enhanced entry of bacteria into domes. By electron microscopy, intact bacilli with electron-transparent zones (peribacillary spaces) were in the supranuclear cytoplasm of M cells at 20 hours. M cells also contained vacuoles, including electron-dense material interpreted as degraded bacilli. Subepithelial and intraepithelial macrophages contained bacilli and degraded bacterial material in phagosomes. These results suggest that calf ileal M cells take up bacilli, and that subepithelial and intraepithelial macrophages secondarily accept bacilli or bacterial debris which are expelled from M cells.

A cytological study of the development of Erysiphe graminis in its host barley, as influenced by the two fungicides ethirimol and propiconazole

1990 ◽  
Vol 68 (12) ◽  
pp. 2618-2628 ◽  
Author(s):  
Annerose Heller ◽  
Friedrich Grossmann ◽  
Burkhard Frenzel ◽  
Sigrun Hippe
Keyword(s):  
Electron Microscopy ◽  
Host Cell ◽  
Light And Electron Microscopy ◽  
Unknown Origin ◽  
Erysiphe Graminis ◽  
Dense Material ◽  
Ultrastructural Changes ◽  
Wall Thickening ◽  
Electron Dense Material ◽  
Host Parasite

Light and electron microscopy of barley epidermal cells treated with ethirimol or propiconazole and then inoculated with Erysiphe graminis f. sp. hordei showed the complex reaction of this host–parasite system to fungicides. The completely different biochemical modes of action of the two fungicides were reflected in the ultrastructural changes observed. Specific fungicidal effects could be distinguished from degenerative processes associated with senescence of untreated plants. For ethirimol, the first changes to be observed in the nucleus were blebbing of the outer nuclear membrane, invaginations into the nucleoplasm, and loss of the dark-staining material of nuclear pores. Later on, large areas of the cytoplasm were devoid of ribosomes. Moreover, electron-dense material was found in the perinuclear space and in cisternae of the endoplasmic reticulum. Round bodies, containing electron-dense material of unknown origin, appeared in the cytoplasm. Propiconazole, on the other hand, caused severe malformations of haustoria, host cell wall appositions, and wall thickening. The sheaths surrounding the haustoria were significantly enlarged, and vesicular and multivesicular bodies appeared in the extrahaustorial matrix. In later stages, degenerated haustoria were partially encapsulated by the host cell. Large, rectangular, electron-opaque structures, termed Fibrosinkörper, were observed in secondary hyphae. Both fungicides tested caused swelling of secondary hyphae. Key words: Erysiphe graminis f.sp. hordei, ethirimol, propiconazole, host–parasite system, cytology, electron microscopy.

Visualization of changes in ciliary tip configuration caused by sliding displacement of microtubules in macrocilia of the ctenophore Beroe

1985 ◽  
Vol 79 (1) ◽  
pp. 161-179 ◽  
Author(s):  
S.L. Tamm ◽  
S. Tamm
Keyword(s):  
Electron Microscopy ◽  
Dense Material ◽  
Bend Angle ◽  
Two Dimensional ◽  
Electron Dense Material ◽  
Central Pair ◽  
Rest Position ◽  
Recovery Stroke ◽  
Dimensional Models ◽  
As If

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.

Spermiogenesis and spermatozoon of the tapeworm Parabothriocephalus gracilis (Bothriocephalidea): Ultrastructural and cytochemical studies

2010 ◽  
Vol 55 (1) ◽  
Author(s):  
Lenka Šípková ◽  
Céline Levron ◽  
Mark Freeman ◽  
Tomáš Scholz
Keyword(s):  
Electron Microscopy ◽  
Anterior Extremity ◽  
Mature Spermatozoon ◽  
Dense Material ◽  
Apical Region ◽  
Cortical Microtubules ◽  
Electron Dense Material ◽  
Dense Granules ◽  
Cytoplasmic Extension ◽  
Transmission Electron

AbstractSpermiogenesis and spermatozoon ultrastructure of the tapeworm Parabothriocephalus gracilis were described using transmission electron microscopy (TEM). Spermiogenesis is characterized by the formation of a zone of differentiation with two centrioles associated with striated rootlets, and an intercentriolar body between them. The two flagella undergo a rotation of 90° until they become parallel to the median cytoplasmic extension with which they fuse. Electron-dense material is present in the apical region of the zone of differentiation in the early stages of spermiogenesis. This electron-dense material is characteristic for the orders Bothriocephalidea and Diphyllobothriidea. The mature spermatozoon contains two axonemes of the 9 + ‘1’ trepaxonematan pattern, nucleus, parallel cortical microtubules and electron-dense granules of glycogen. The anterior extremity of the spermatozoon exhibits a single helical electron-dense crested body 130 nm thick. One of the most interesting features is the presence of a ring of cortical microtubules surrounding the axoneme. This character has been reported only for species of the order Bothriocephalidea and may be unique in this cestode group.

scholarly journals Development and ultrastructure observations of secondary hyphae of Podosphaera leucotricha on apple cultivars of varying susceptibility to powdery mildew

2017 ◽  
Vol 38 (SI 2 - 6th Conf EFPP 2002) ◽  
pp. 425-428
Author(s):  
E. Rakhimova
Keyword(s):  
Electron Microscopy ◽  
Powdery Mildew ◽  
Light And Electron Microscopy ◽  
Dense Material ◽  
Podosphaera Leucotricha ◽  
Powdery Mildew Fungus ◽  
Full Complement ◽  
Apple Cultivars ◽  
Host Parasite

The development and ultrastructure feature of secondary hyphae of Podosphaera leucotricha were studied using light and electron microscopy. The percentage of development and length of secondary hyphae, differed in compatible and incompatible combinations. In compatible host-parasite combinations, hyphal cells of powdery mildew fungus contained a full complement of fungal organelles. There were differences of hyphal ultrastructure in compatible and incompatible host-parasite combinations, the main one was the appearance of dense material inside the nucleus, in the cytoplasm, and a few mitochondria.

Selective Staining of Cortical Granules and Golgi Cisternae in Arbacia Punctulata

1969 ◽  
Vol 27 ◽  
pp. 286-287
Author(s):  
Arya K. Bal ◽  
Gilles H. Cousineau
Keyword(s):  
Electron Microscopy ◽  
Light Microscope ◽  
Phosphotungstic Acid ◽  
Dense Material ◽  
Cortical Granules ◽  
Light Microscope Level ◽  
Electron Dense Material ◽  
Selective Staining ◽  
Arbacia Punctulata ◽  
Staining Techniques

Cyto-chemical staining techniques at the light microscope level have revealed the presence of mucopolysaccharides and proteins in the cortical granules of Eichinoderm eggs. In routine electron microscopy preparation the cortical granules appear to have two morphologically distinct components - an electron dense inner component (dark bodies) surrounded by a less-electron dense material. In the present investigation it has been made possible to stain the dense inner material selectively with Phosphotungstic acid (PTA) in non-osmicated aldehyde fixed oocytes and eggs of Arbacia punctulata.

SEM observations on egg-shell of the Japanese tusser, Antheraea yamamai and Chinese tusser,Antheraea pernyi

1990 ◽  
Vol 48 (3) ◽  
pp. 98-99
Author(s):  
Hu Cui ◽  
Jian Hong ◽  
Gao Oikang ◽  
Wu Xiaojiang ◽  
Ye Gongyin
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Fine Structure ◽  
Surface Structure ◽  
Shell Surface ◽  
Antheraea Pernyi ◽  
Egg Shells ◽  
Egg Shell ◽  
Scanning Electron

The egg-shell surface structure of the Japanese tusser and Chinese tusser was observed by means of scanning electron microscopy. There were a lot of similarities between the two egg-shells, but the fine structure may be easily distinguished. As to the Japanese tusser, the petals of the petaloid pattern around micropyle were elongate and raised in the middle (Fig. 1); micropylar tubes numbered 11-13 (Figs. 2 and 3); the wider and thicker bank formed irregularly shaped net-like structure of the egg-shell surface other than in the vicinity of micropyle (Fig. 5); and the thickness of the egg-shell was about 70 μm. In the Chinese tusser the petals were shorter, wider,and even; micropylar tubes numbered 8-9 (Fig. 4); the narrow and low bank formed hexagonal, pentagonal, heptagonal, or octagonal net-like structure; the aeropyle wall was well developed, almost the same in size (Figs. 8 and 9); and the thickness of the egg-shell was about 40 μm.

The development of the tegument and cercomer of the polycephalic larvae (cercoscolices) ofParicterotaenia paradoxa(Rudolphi, 1802) (Cestoda: Dilepididae) at the ultrastructural level

Parasitology ◽  
1984 ◽  
Vol 88 (1) ◽  
pp. 117-130 ◽  
Author(s):  
Barbara M. MacKinnon ◽  
M. D. B. Burt
Keyword(s):  
Electron Microscopy ◽  
Developmental Stage ◽  
Cyst Wall ◽  
Proximal Part ◽  
Ultrastructural Level ◽  
Dense Material ◽  
Follicular Cells ◽  
Electron Dense Material ◽  
Inner Surface ◽  
Distal Surface

SUMMARYThe development of the tegument and cercomer ofParicterotaenia paradoxapolycephalic larvae was examined using electron microscopy. Larvae are formed by budding from the inner surface of the tegument of the degenerating hexacanth embryo. A new secondary tegument formed around the larvae is probably produced from the original hexacanth sub-tegumental cells. Microvilli covering the surface of young larvae are converted directly into microtriches, as the larvae develop, by addition of electron-dense material to the proximal part of the microvillus. Remnants of the original microvillus are visible at the distal surface of each new microthrix, but they eventually degenerate. The cercomer homologue is represented by scattered follicular cells, bearing microvilli, lying just within the containing cyst wall. The continuity of tegumentary tissue from one developmental stage to the next is discussed.

scholarly journals Observations on the Mycorrhizas of Forest Trees. II. The Rhizosphere of Pinus Radiata D. Don

1967 ◽  
Vol 20 (5) ◽  
pp. 915 ◽  
Author(s):  
RC Foster ◽  
GC Marks
Keyword(s):  
Electron Microscopy ◽  
Clay Minerals ◽  
Pinus Radiata ◽  
Light And Electron Microscopy ◽  
Fungal Species ◽  
Forest Trees ◽  
Large Numbers

Two common mycorrhiza types of Pinus radiata were examined by light and electron microscopy. Large numbers of bacteria and fungal species other than those forming the mycorrhiza as well as diatoms were observed in the mycorrhizosphere. Different morphological types of bacteria were characteristic of different mycorrhizal types, and in some cases the bacteria were associated with lysed regions of the mantle. The distribution of the bacteria within the rhizosphere is discussed in relation to the clay minerals and the carbohydrate and polyphenol metabolisms of the host.

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