Leishmania

Zuckerman, Avivah; Lainson, Ralph

doi:10.1016/b978-0-12-426001-6.50009-8

Cited by 23 publications

(14 citation statements)

References 84 publications

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“…are parasitic protozoa with two principle stages in their life cycle (52). The promastigote is a flagellated, extracellular organism that colonizes the alimentary tract of the sand fly vector.…”

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confidence: 99%

Structure and regulation of histone H2B mRNAs from Leishmania enriettii.

Genske¹,

Cairns²,

Stack³

et al. 1991

Mol. Cell. Biol.

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We have studied the structure and expression of histone H2B mRNAs and genes in the parasitic protozoan Leishmania enriettii. A genomic clone containing three tandemly repeated genes has been sequenced and shown to encode three identical histone proteins and two types of closely related mRNA sequence. We have also sequenced three independent cDNA clones and demonstrated that the Leishmania H2B mRNAs are polyadenylated, similar to the basal histone mRNAs of higher eucaryotes and the histone mRNAs of yeast. In addition, the Leishmania mRNAs contain inverted repeats near the poly(A) tail which could form stem-loops similar in secondary structure, but not in sequence, to the 3' stem-loops of nonpolyadenylated replication-dependent histones of higher eucaryotes. Unlike the replication-dependent histones, the Leishmania histone H2B mRNAs do not decrease in abundance following treatment with inhibitors of DNA synthesis. The histone mRNAs are differentially expressed during the parasite life cycle and accumulate to a higher level in the extracellular promastigotes (the form which in nature lives within the gut of the insect vector) than in the intracellular amastigotes (the form that lives within the mammalian host macrophages).Leishmania spp. are parasitic protozoa with two principle stages in their life cycle (52). The promastigote is a flagellated, extracellular organism that colonizes the alimentary tract of the sand fly vector. Promastigotes, which are injected from the insect salivary glands into a vertebrate host by a bite by the infected insect, are phagocytized by the host macrophages; within the lysosomes of the macrophages, the parasites transform into the other life cycle stage, the amastigotes. The oval, nonflagellated amastigotes are specialized for survival within the macrophage lysosomes, where they divide, lyse the host cell, and reinvade new macrophages. The life cycle is completed when a sand fly ingests the infected macrophages during a blood meal and the parasites retransform into the promastigote forms within the insect gut.Leishmania spp. and other related kinetoplastid protozoa are among the most primitive eucaryotes; phylogenetic studies have placed them well below either fission or budding yeasts on an evolutionary scale (45). As a reflection of this phylogenetic divergence, these organisms possess many unusual features of gene expression. trans splicing of mRNAs (1,33,49), transcriptional editing of mitochondrial RNAs (42), and polycistronic mRNA precursors (32) are features found commonly among the kinetoplastid protozoa but not observed as frequently in other eucaryotes. Other novel mechanisms for expressing or regulating the expression of genetic information are likely to be discovered in these protozoa.Histones are proteins that are ubiquitous among eucaryotes (24). These small basic polypeptides constitute five classes of protein which are essential elements of eucaryotic chromatin: histones Hi, H2A, H2B, H3, and H4. Two copies each of histones H2A, H2B, H3, and H4 form an octamer around w...

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mentioning

confidence: 99%

Structure and regulation of histone H2B mRNAs from Leishmania enriettii.

Genske¹,

Cairns²,

Stack³

et al. 1991

Mol. Cell. Biol.

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“…Trypanosomatid protozoans of the genus Leishmania live in two very different environments during their life cycle (19). Promastigotes are extracellular, flagellated organisms that colonize the alimentary tract of the sandfly vector, while amastigotes are nonmotile intracellular parasites that live in the lysosomal vesicles of the vertebrate host macrophages.…”

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confidence: 99%

Structural isoforms of a membrane transport protein from Leishmania enriettii.

1990

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A membrane transport protein of the glucose transporter superfamily from Leishmania enriettii is encoded by a family of tandemly repeated genes. The first gene in this tandem repeat codes for a structural isoform that contains a unique amino-terminal hydrophilic domain, probably located in the cytoplasm; the remainder of the protein is identical to the polypeptide encoded by the internal genes in the tandem repeat. The unique isoform is represented by a distinct stable RNA.

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“…ΚΤΗΝ. ΕΤΑΙΡΕΙΑΣ 1998, 49 (1) http://epublishing.ekt.gr | e-Publisher: EKT | Downloaded at 12/05/2018 10:59:20 | φάγα αναπτύσσονταν σε φιαλίδια κατά τον ίδιο τρόπο, χωρίς σινεφουνγινη, αλλά με την προσθήκη ίσου όγκου με αυτή αποστειρωμένου PBS (μάρτυρες). Τα κύτταρα επωάζονταν στους 37°C σε ατμόσφαιρα C0 2 5% 10 .…”

Section: υλικο και μεθοδοςunclassified

“…ΚΤΗΝ. ΕΤΑΙΡΕΙΑΣ 1998, 49 (1) με τα μακροφάγα για δυο ώρες ήταν προφανής η προ σκόλληση τους στην επιφάνεια των μακροφάγων ως επί το πλείστον με την άκρη του μαστίγιου τους. Τα στελέχη που μελετήθηκαν, δεν παρουσίασαν ποσοστιαία μεταβο λή του βαθμού προσκόλλησης τους στην επιφάνεια των μακροφάγων, όταν ο χρόνος επώασης αυξήθηκε από 2 σε 24 ώρες.…”

Section: συζητησηunclassified

Effect of Sinefungin on the attachment of the parasite Leishmania to the macrophages cell line J774G8

Tzora

Lawrence

Robert-Géro

2018

J Hellenic Vet Med Soc

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The effect of Sinefungin on the attachment of the Leishmania strains L. infantum, L. tropica and L. major to the macrophages cell line J774G8 was studied. Inhibition ofthe attachment to the surface of macrophages was observed to the Sinefungin sensitive strains L. tropica and L. major. This inhibition was obtained only for Sinefungin pretreated promastigotes (72 hours with 2.6 and 26 Μμ Sinefungin) when incubated with macrophages for 2 and 24 hours. After 2 h incubation period of the promastigote forms of the sensitive L. tropica with macrophages, the inhibition of the attachment was 100%, whereas for the sensitive L. major strain the inhibition was 17 and 36% at a concentration of Sinefungin 2.6 and 26 μΜ respectively. The percentage of the inhibition 24 h post infection was in the range of 52 to 77% for the L. tropica strain and from 73 to 86% for the L. major strain for promastigote pretreated with 2.6 and 26 μΜ Sinefungin respectively. Controls showed that Sinefungin was not toxic for the macrophages when used for 3 days at the above mentioned concentrations. Inhibition of the protozoa - macrophage cell line J774G8 adherence was a common finding leading us to the conclusion that Sinefungin is involved actively into that process.

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Leishmania

Cited by 23 publications

References 84 publications

Structure and regulation of histone H2B mRNAs from Leishmania enriettii.

Structure and regulation of histone H2B mRNAs from Leishmania enriettii.

Structural isoforms of a membrane transport protein from Leishmania enriettii.

Effect of Sinefungin on the attachment of the parasite Leishmania to the macrophages cell line J774G8

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