Virus-like particles in Leishmania parasites

Dh, Molyneux

doi:10.1038/249588a0

Cited by 49 publications

(24 citation statements)

References 5 publications

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“…(1986), liposomes containing a wax-like material noted by Scorza et at. (1979) in the amastigotes of L. garnhami, and the virus-like particles in L. hertigi were described by Molyneux (1974). None of these bodies were seen during the present study.…”

Section: Discussionmentioning

confidence: 70%

Ultrastructural studies on cutaneous leishmaniasis in Ecuador.

Bhutto

Okada

Nonaka

et al. 1992

Jap. J. Trop. Med. Hyg.

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Ultrastructural observations were made of the lesions of three Ecuadorian patients with cutaneous leishmaniasis. Parasites were located both within the macrophages, either inside the intracytoplasmic vacuoles (parasitophorous vacuoles) or free in cytoplasm and outside host cells. Amastigotes were rounded or oval with a mean length of 2.62 ,urn (±0.17 S.D.) and mean width of 2.18 ,urn (±0.28 S.D.). Parasites showed degeneration intracellularly both within the vacuoles and in the cytoplasm of macrophages. Lymphocytes were seen in close contact with parasitized macrophages as well as directly attached to the parasites. Furthermore, spongiotic vesicle was observed in the epidermis where Leishmania parasites were found, surrounded by lymphocytes and other mononuclear cells. Amastigotes attached to mononuclear cells were also observed inside and between the keratinocytes. Mononuclear cells containing melanin granules showed amastigotes in their cytoplasm.The parasite-macrophage relationship, the role of T-cells in combating the parasites and the fate of the parasites inside the host body are d~ussed.

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Section: Discussionmentioning

confidence: 70%

Ultrastructural studies on cutaneous leishmaniasis in Ecuador.

Bhutto

Okada

Nonaka

et al. 1992

Jap. J. Trop. Med. Hyg.

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“…Its distribution among only one or two of the stocks we examined, the size and morphology of the particle associated with the LR1 RNA, the size of the RNA, its maintenance during fly transmission, and its apparent cytoplasmic location are consistent with its being an RNA virus. Interestingly, the virus-like particles seen in L. hertigi (3) are also restricted to the cytoplasm. The effects of LR1 on the parasite are not obvious.…”

Section: Discussionmentioning

confidence: 99%

“…DNA viruses have been reported in Amoeba (1) and virus-like particles have been observed in several Plasmodium species (1), in Nagleria (1), in Endotrypanum (2), in the cytoplasm of Leishmania hertigi (3,4), and in the flagellum of Trypanosoma melophagium (5). Double-stranded RNA viruses have been found in Giardia (6) and Trichomonas (7).…”

mentioning

confidence: 99%

LR1: a candidate RNA virus of Leishmania.

Tarr

Aline

Smiley

et al. 1988

Proc. Natl. Acad. Sci. U.S.A.

139

115

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Although viruses are important biological agents and useful molecular tools, little is known about the viruses of parasites. We report here the discovery of a candidate for an RNA virus in a kinetoplastid parasite. This potential virus, which we term LR1, is present in the promastigote form of the human pathogen Leishmania braziliensis guyanensis CUMC1-1A but not in 11 other stocks ofLeishmania that were examined nor in Trypanosoma brucei. The candidate viral RNA has a size of -6000 nucleotides, is single-stranded, and is largely, if not exclusively, located in the cytoplasm. No homologous LR1 sequences are detected in genomic DNA. The candidate viral RNA is associated with a spherical particle 32 nm in diameter that has a sedimentation coefficient of =130 S. There is as yet no evident effect of this potential virus on parasite physiology or the disease caused by the parasite.The presence of viruses in parasitic protozoa may be relevant to the diseases caused by these organisms and may be useful for molecular biological studies. DNA viruses have been reported in Amoeba (1) and virus-like particles have been observed in several Plasmodium species (1), in Nagleria (1), in Endotrypanum (2), in the cytoplasm of Leishmania hertigi (3, 4), and in the flagellum of Trypanosoma melophagium (5). Double-stranded RNA viruses have been found in Giardia (6) and Trichomonas (7). In addition, circular DNAs have been detected in Leishmania (8).We report here the discovery and preliminary characterization of a multicopy RNA in the cytoplasm ofLeishmania braziliensis guyanensis that is associated with a spherical particle 32 nm in diameter. This may be an RNA virus, to the best of our knowledge, the first virus found in a kinetoplastid parasite.MATERIALS AND METHODS Organisms. The Leishmania stocks examined in this study are shown in Table 1. They were grown as the promastigote forms at 28°C as described (9).Nucleic Acid Isolation. Total cellular RNA was prepared by the urea/phenol/cesium chloride method (10). Genomic DNA was prepared as described in Milhausen et al. (11). Gel purified LR1 RNA was prepared from 1.35 x 1010 L. braziliensis guyanensis CUMC1-1A cells by lysis in 5 ml of 1% NaDodSO4/proteinase K (1 mg/ml)/25 mM EDTA for 1 hr at 50°C. Chromosomal DNA was removed by potassium acetate precipitation and the supernatant was precipitated with 1-propanol, resuspended, and electrophoresed in a 0.7% agarose gel in TBE (89 mM Tris borate, pH 8.3/2 mM EDTA). The 6000-nucleotide band was excised from the gel, reelectrophoresed, electroeluted, and ethanol-precipitated.Electrophoresis and Hybridizations. Pulse-field gel electrophoresis was performed as described (9). RNA was electrophoresed either in 1.2% agarose/2.2 M formaldehyde gels as described (10) or in native 0.6% agarose gels in TBE at 1.8 V/cm for 12-16 hr. After electrophoresis RNA was treated with 50 mM NaOH for 30 min and transferred to a Nytran membrane (Schleicher & Schuell) (10). Hybridization to the LR1 cDNA riboprobe was carried out in 50% (vol/vol) formam...

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“…fu ngal viruses is unknown. Compounds other than cycloheximide have been shown as well to selectively inhibit fungal virus replication (22, 23, 64, 66a), and thermotherapy has been used to inhibit viral synthesis in species of Penicillium (144,172), Sac charomyces cerevisiae (26 1, 269), and Agaricus bisporus (72). Volterra and coworkers (264) have shown that fluctuations in relative titers of two viruslike particles in a given mycelium of P. citrinum can occur spontaneously, resulting in phenotypic segregation in the host fo r growth and sporulation efficiency.…”

Section: Polymerase Activitymentioning

confidence: 99%