Light and Electron Microscopic Observations on Encystment of <i>Acanthamoeba palestinensis</i>, Reich

Lasman, M.

doi:10.1111/j.1550-7408.1977.tb00972.x

Cited by 16 publications

(17 citation statements)

References 18 publications

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“…The mature cysts are surrounded by two thick walls which form the exocyst and an endocyst that is closely apposed to the cell membrane. The nuclear membrane forms projections with vesicles bounded by double membranes, and very dense bodies of different sizes are found in the nucleus of every cyst 38 39. This high resistance of the cyst walls and the nuclear proteins that keep DNA condensed may explain the results that could have been obtained by using DNA-extraction procedures validated for viruses or bacteria if cysts are not properly lysed; it should be expected that the annealing of the primers and probes cannot be achieved because the parasite DNA is not available.…”

Section: Discussionmentioning

confidence: 99%

Resistance of Acanthamoeba to classic DNA extraction methods used for the diagnosis of corneal infections

Goldschmidt

Degorge

Saint-Jean

et al. 2007

British Journal of Ophthalmology

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Aims: Sensitive diagnosis of Acanthamoeba infections may prevent the clinical condition from becoming worse. In order to improve the diagnosis tool performances, we studied the implication of the DNA extraction procedures on the detection of Acanthamoeba by real-time PCR. Methods: Acanthamoeba cysts mixed with a tag virus were processed according to different DNA preparation procedures: heat, Proteinase K (ProtK), alkali lysis, QIAmp kitH, MagNA Pure (DNA Mini kit, MagNA PureH Nucleic Acid isolation kit), ProtK+QIAmp and ProtK+MagNA Pure. Parasite-DNA loads were assessed by real-time PCR. Results: The results show that the structures of Acanthamoeba cysts are resistant to reagents releasing the DNA from other cells and viruses. Heat, NaOH or ProtK did not allow the DNA extraction yields to be assessed or the inhibitors to be eliminated The QIAmp and the MagNA Pure partially improved the sensitivity of the PCR and eliminated the inhibitors. A significant increase in positive results was obtained with a ProtK treatment before commercial extraction kits. ProtK+MagNA Pure yielded the highest rates of positivity. Conclusion: To minimise false negative results, the nucleic-acid based Acanthamoeba diagnosis requires, first, the efficient lysis of cysts (without affecting the DNA) to make the DNA available for extraction and amplification, and, second, the elimination of PCR inhibitors. A significant increase in the detection rates is obtained by adding a ProtK treatment (10 min at 56uC) before the commercial procedures. ProtK+MagNA Pure yielded the best results in 30 min, followed by ProtK+QIAmp (150 min).Acanthamoeba are free-living organisms with a life cycle characterised by two stages, an actively dividing trophozoite developing hyaline pseudopodia and a quiescent cyst. Acanthamoeba are present in air, soil, dust, air-conditioning units, treated water, bottled water, swimming pools, dialysis units, eyewash stations, contact lenses and lens cases, and are considered among the most prevalent eukaryotic protozoa found in the environment.

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Section: Discussionmentioning

confidence: 99%

Resistance of Acanthamoeba to classic DNA extraction methods used for the diagnosis of corneal infections

Goldschmidt

Degorge

Saint-Jean

et al. 2007

British Journal of Ophthalmology

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“…The SEM examination of intracellular structures of ciliates, however, has been scarcely attempted. Earlier we applied the styrene-resin fracturing method (20) for the observation of inner structures of rumen ciliates and were able to get good pictures of organelles, such as nuclei and inclusion granules ( 10).…”

Section: Discussionmentioning

confidence: 99%

“…Then they were immersed overnight in styrene monomer without catalyst. After that, the specimens were embedded in styrene monomer with catalyst in uncovered capsules at 60°C, and ground to a powder with a pestle in a ceramic mortar ( 10). Powdered specimens were placed into test tubes and the styrene resin removed with propylene oxide.…”

Section: Methodsmentioning

confidence: 99%

“…Therefore the amoeba is useful for the investigation of cell structure and function and organellar changes during the cell cycle. The fine structure of encysting cells and cysts has been described in an earlier paper (10). In the course of electron microscopic observations of the trophozoite, special features of the amoeba's organelles-the Golgi complex, microbodies, and mitochondria-have been revealed.…”

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confidence: 91%

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Further Observations on the Fine Structure of Acanthamoeba palestinensis (Reich, 1933). The Golgi Complex, Microbodies, and Mitochondria¹

Lasman¹,

Feinstein²

1983

The Journal of Protozoology

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The fine structure of the trophozoite of Acanthamoeba palestinensis with a special emphasis on the Golgi complex, microbodies, and mitochondria has been examined. Golgi complexes are distributed throughout the cytoplasm but are most abundant in the perinuclear region. Usually two Goigi complexes are found in the same plane on opposite sides of the nucleus. One of them appears to be in an intimate association with the nuclear membrane. The region of contact contains compact cisternae, vesicles of various sizes, as well as granular and amorphous electron‐dense material. Structural changes in the nuclear envelope are also observed in this area. A structure consisting of a Golgi complex and electron‐dense microtubule organizing center, comparable to the centrosphere of other Acanthamoeba species, has been observed. Microbodies, surrounded by a single unit membrane and containing a granular matrix and tubular inclusions, are scattered throughout the cytoplasm. These organelles, circular (∼1 μm in diameter) or ovoidal (∼1 μm in length and ∼0.5 μm in width) in section, have often an irregular outline. These microbodies are probably the morphological equivalent of peroxisomes and glyoxysomes. Most mitochondria show a typical structure including tubular cristae and intracristal inclusions. Occasionally mitochondria with two apposed double membranes running through the midline are found. Such atypical cristae have never been reported in small amoebae before.

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“…Nucleoluslike bodies connected with the chromosomes appear in the micronuclei of Tetrahymena [27]. Dense spheres are formed in the nuclei of the amoeba Acanthamoeba pafestinesis [23]. Fibrillar spheres which are linked with chromosomes, have been ob-served in micronuclei of Didinium [20] and Stentor (Skarlato, 1979, Abstract) Nearly all are, however, as in the case of reports on viruses, incidental findings arising from and based exclusively on ultrastructural studies, and their physiological significance has not been clarified.…”

Section: Co-conjugant Clonesmentioning

confidence: 99%

Evidence for a Viral Macronuclear Endosymbiont in Paramecium caudatum

Tsukii

Harumoto

Yazaki

1995

J Eukaryotic Microbiology

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Some strains of P. caudaturn contain macronuclear inclusion bodies that are morphologically distinct from bacteria. They vary in number as well as in size in each macronucleus. The inclusion bodies are basically divided into peripheral and inner areas. The peripheral area consists of fibrillar proteins of 22-24 nm in thickness, which are specifically stained with fast green in 45% acetic acid. On the other hand, chromatin-like granules are within the inner area of large inclusion bodies. The granules within the inner area changed their distribution depending upon the physiological state of their host cells. Transplantation experiments and crossbreeding analyses revealed that genetic factors responsible for the multiplication of the inclusion bodies can 'infect' other macronuclei (or cells) via the cytoplasm. These results suggest that the inclusion bodies are a non-bacterial macronuclear endosymbiont, possibly produced by a virus or a virus-like element.Supplementary key words. Ciliate, fibrillar sphere, inclusion body, macronucleus, transplantation.ILIATES are known to have many bacterial endosym-C bionts: some are in cytoplasm and others in macro-or micronucleus [ 14,30,43]. Caedibacter taeniospiralis, the genetic elements for the cytoplasmic inheritance of killer trait [44], as well as other endosymbiotic killer bacteria grow in cytoplasm [32, 341. Holospora obtusa and related species are the macroor micronuclear endosymbionts [ 12, 15, 161.In contrast, reports on viruses or plasmids in ciliates are scarce, and all are in the bacterial or algal endosymbionts. Viruses found in P. aurelia complex are located within the endosymbiotic killer bacteria [32-351 and the virus-like particles within endosymbiotic chlorella of P. bursaria [2 I]. No one has ever described viruses or plasmids directly inhabiting host cells. Ciliates are also known to have various inclusions such as "helical fibrils" (or simply "helices"), "spheres" and "crystalloids" in macroand micronuclei as well as in the cytoplasm [37]. Helical fibers were found in Euplotes [4, 401. Fibrillar "spheres" occurred in many ciliates, e.g. Loxodes [36], Zchthyophthirius [ 181, Didinium [20] and Stentor (Skarlato, 1979, Abstract. Fine structure of the micronuclei of the ciliate Stentor coeruleus during meiosis. J. Protozool., 26:36A.) Crystalloids were components of the macronucleus in Tracheloruphis [38]. Nearly all these inclusions were, however, incidental findings, and their physiological significances have been so far unclarified.This report demonstrates that the macronuclear inclusion bodies found in Paramecium caudatum are a non-bacterial endosymbiont, which can autonomously multiply within macronuclei and infect to other cells via cell to cell contact (conjugation). Though infection experiments using extracellular fluid has been unsuccessful, it is possible that this new endosymbiont was derived from infection of fibrillar viruses or plasmids [6].A preliminary report described on the finding of the inclusion bodies (Tsukii, Y. & Harumoto, T. 1984. A...

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Light and Electron Microscopic Observations on Encystment of Acanthamoeba palestinensis, Reich

Cited by 16 publications

References 18 publications

Resistance of Acanthamoeba to classic DNA extraction methods used for the diagnosis of corneal infections

Resistance of Acanthamoeba to classic DNA extraction methods used for the diagnosis of corneal infections

Further Observations on the Fine Structure of Acanthamoeba palestinensis (Reich, 1933). The Golgi Complex, Microbodies, and Mitochondria¹

Evidence for a Viral Macronuclear Endosymbiont in Paramecium caudatum

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Light and Electron Microscopic Observations on Encystment of Acanthamoeba palestinensis, Reich

Cited by 16 publications

References 18 publications

Resistance of Acanthamoeba to classic DNA extraction methods used for the diagnosis of corneal infections

Resistance of Acanthamoeba to classic DNA extraction methods used for the diagnosis of corneal infections

Further Observations on the Fine Structure of Acanthamoeba palestinensis (Reich, 1933). The Golgi Complex, Microbodies, and Mitochondria1

Evidence for a Viral Macronuclear Endosymbiont in Paramecium caudatum

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Further Observations on the Fine Structure of Acanthamoeba palestinensis (Reich, 1933). The Golgi Complex, Microbodies, and Mitochondria¹