Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
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Immunization with the GP46/M-2 membrane glycoprotein of Leishmania amazonensis has been shown to induce a protective immune response against infection. We have surveyed a variety of trypanosomatid species and genera for the presence and expression of this gene family, information that will be relevant to future vaccine studies against leishmaniasis. Molecular karyotype analysis revealed the presence of GP46/M-2 genes in all members of the Leishmania mexicana complex, Leishmania major, Leishmania donovani, Leishmania tarentolae, and Crithidia fasciculata. In contrast, DNAs from species of the Leishmania braziliensis complex (L. braziliensis, Leishmania guyanensis, and Leishmania panamensis) failed to hybridize to GP46/M-2 probes. Western blot analyses with several polyclonal antisera against the GP46/M-2 protein revealed protein expression in L. major and L. donovani, but not L. panamensis or L. braziliensis. Phylogenetic analysis suggests that a loss of the GP46A gene family occurred following separation of the L. braziliensis complex, prior to speciation events within this complex. These data indicate that GP46/M-2 membrane glycoprotein may not be critical to parasite survival, but may play an ancillary role during the developmental cycle.
Mol Biochem Parasitol 1992 Jan
PMID:Loss of the GP46/M-2 surface membrane glycoprotein gene family in the Leishmania braziliensis complex. 154 9

In the genus Leishmania there has been no convincing demonstration of genetic exchange, and it has been proposed that reproduction is clonal. However, preliminary characterization of two strains of Leishmania isolated from wild animals in a zoonotic focus of cutaneous leishmaniasis in the Eastern Province of Saudi Arabia, has suggested that they may represent hybrids of Leishmania major and Leishmania arabica. Evidence presented here strongly supports this hypothesis. Isoenzyme analysis and molecular karyotyping of cloned organisms indicated that the putative hybrids are distinct from other species of Leishmania, and possess characteristics of both L. major and L. arabica. Experiments using highly specific probes demonstrated that kinetoplast minicircle DNA from the putative hybrid contained L. major-specific, but not L. arabica-specific sequences. DNA fingerprinting data obtained using 6 genomic DNA probes were consistent in all cases with a L. major/L. arabica recombinant genotype, and implied both diploidy and allelic segregation. These observations suggest that sexual reproduction may generate genetic diversity within natural Leishmania populations.
Mol Biochem Parasitol 1991 Jun
PMID:Evidence of genetic recombination in Leishmania. 165 55

Toward the future development of a defined subunit vaccine against leishmaniasis is, high levels of recombinant GP63 for diverse species of Leishmania were produced in Escherichia coli. Several features of Leishmania GP63 genes were simultaneously modified with the polymerase chain reaction (PCR) using either cloned genes or total genomic DNA from Leishmania as template DNA for the PCR amplification reactions. The PCR products included only the coding region for the predicted mature form of GP63 that occurs on the surface of Leishmania, flanked by the appropriate translation signals and cloning sites for the production of recombinant GP63 as nonfusion protein in E. coli. When the codon usage in the GP63 gene was modified to reduce the guanine and cytosine content for the codons adjacent to the ATG initiation codon, rGP63 represented about 50% of total protein in E. coli. Mouse monoclonal antibodies raised against purified Leishmania major rGP63 had equivalent immunoblotting characteristics for native GP63 and recombinant GP63 with respect to linear determinants on GP63 expressed in diverse species of Leishmania. Human T cell lines and clones were derived from a patient infected with Leishmania braziliensis panamensis using rGP63 purified from an L. major GP63 expression clone as antigen.
Mol Biochem Parasitol 1991 Feb
PMID:Modification of GP63 genes from diverse species of Leishmania for expression of recombinant protein at high levels in Escherichia coli. 171 Nov 53

The pathological and electron-microscopic features of the first case of autochthonous leishmaniasis affecting a domestic goat in Kenya are described. They are similar to what have been described in man and other animals. Using a short amino-acid sequence common to all the species of leishmania as primers for kDNA synthesis, the intervening sequence of 120 bases was amplified in the goat's tissues by polymerase chain reaction (PCR). The leishmania kinetoplast DNA sequence was detected in all the different infected tissues of the goat examined. The sensitivity and specificity of this assay are discussed. The result of the assay used was consistent with the parasite being either L. major or L. aethiopica as the infecting agent. The isoenzyme studies were consistent with L. aethiopica as the strain responsible for this goat's infection. The control of leishmaniasis and its vector must take into account the potential role of animal reservoirs in the environment. Even though Kenya and other East African countries are endemic for kala-azar, the presence of kala-azar in goats is of considerable veterinary public health importance in Africa. Efforts must not be spared to identify and detect other possible animal reservoirs in the subregion. Using DNA amplification techniques, which are sensitive and specific, such as the one described in this paper, sera and other biological fluids and tissues from different animal species should be utilized for detecting additional reservoirs for leishmania parasites particularly in known endemic areas of the world.
Mol Cell Probes 1991 Oct
PMID:Leishmaniasis in a domestic goat in Kenya. 179 52

Leishmania donovani, the etiological agent for the disease visceral leishmaniasis, attach themselves to the macrophages for initiation of the disease. The attachment process has been found to be regulated by Ca2+ ions. Verapamil, a Ca(2+)-channel blocker inhibits Leishmania-macrophage attachment. The inhibitory effect is increased with time. Nifedipine, another Ca(2+)-channel blocker exhibits the same effect. The attachment process is stimulated by Ca(2+)-ionophore alone. The inhibitory effects of the calcium channel blockers are reversed by the ionophore.
Mol Cell Biochem 1991 Mar 27
PMID:Role of Ca2+ ion on Leishmania-macrophage attachment. 190 82

We report here the cloning of kinetoplast DNA (kDNA) sequences from Leishmania aethiopica in order to develop a specific and sensitive method for the identification of the parasite. Analysis of the cloned kDNA sequences showed different taxonomic specificities demonstrating sequence diversity within the kinetoplast DNA. Cloned whole minicircle hybridized with all Old World Leishmania species tested. Some cloned fragments of minicircle kDNA hybridized with Leishmania species causing cutaneous leishmaniasis in the Old World, but not with the viscerotropic species. Two L. aethiopica-specific clones were found. These clones hybridized with all L. aethiopica isolates tested, but did not react with other Leishmania species. The nucleotide sequence of the L. aethiopica-specific R3 clone is presented. Clones hybridizing with only some of the L. aethiopica isolates were also identified, although none of them showed specificity only for isolates causing localized (LCL) or diffuse (DCL) form of cutaneous leishmaniasis in Ethiopia.
Mol Biochem Parasitol 1991 Feb
PMID:Generation of species-specific DNA probes for Leishmania aethiopica. 205 28

The parasitic protozoa Leishmania are intracellular pathogens which enter host cells through largely undefined mechanisms. One molecule thought to play an important role in this process is gp63, the major glycoprotein on the surface of the infective promastigote form. We have cloned and analyzed the gp63 gene from Leishmania chagasi, an etiologic agent of acute visceral leishmaniasis. The predicted amino acid sequence is highly homologous to that reported for Leishmania major, with the exception of a 56-amino-acid region. This region in L. major was predicted to contain an arginine-glycine-aspartic acid (RGD) sequence that was subsequently hypothesized to be involved in binding to the host cell. The L. chagasi gene lacks this sequence or indeed any RGD sequence, and further studies failed to confirm the existence of an RGD sequence in the L. major gp63 gene. Binding to the host cell surface must therefore be mediated by other sequences in gp63 or by other components of the Leishmania promastigote.
Mol Biochem Parasitol 1990 Mar
PMID:Leishmania gp63 molecule implicated in cellular adhesion lacks an Arg-Gly-Asp sequence. 232 59

The trypanosomatid parasite Leishmania major is one of the principal causal agents of human cutaneous leishmaniasis. Promastigotes grown in vitro undergo growth cycle-dependent differentiation, associated with morphological and biochemical changes, to produce forms which are infective to the mammalian host. By differentially screening a cDNA library constructed from stage-specific mRNA, we have isolated 4 clones encoding mRNAs which show unique or elevated expression in the infective promastigotes of Leishmania major. One of these clones is homologous to a heat-shock protein 70-related gene, that is non-heat-inducible but shows up-regulation during promastigote differentiation. Each of the other cDNAs isolated also recognises multiple transcripts, which show differential regulation between parasite stages and are encoded by repeated, linked nuclear genes. In trypanosomatids, this genomic organisation is indicative of polycistronic transcription.
Mol Biochem Parasitol 1990 Apr
PMID:Isolation of genes showing increased or unique expression in the infective promastigotes of Leishmania major. 234 31

In this report we describe the construction and analysis of a genomic library of Leishmania donovani gene segments in the bacteriophage vector lambda gt11. This cloning vector permits the expression of parasite polypeptides as fusion products with Escherichia coli beta-galactosidase. A group of 90 clones which express L. donovani antigens have been isolated from this library using various polyvalent antisera. Many of these clones appear to encode parasite membrane antigens some of which are recognized by sera from patients with visceral leishmaniasis (kala azar). Some clones reacted with specific subsets of kala azar sera while others reacted with all kala azar sera tested. In addition, some of the clones appear to encode conserved antigens that are recognized by sera from mice immunized with L. major. Preliminary characterization of five clones indicated that each one contains a distinct genetic element and that at least four encode different fusion peptides.
Mol Biochem Parasitol 1986 Apr
PMID:Cloning of Leishmania donovani genes encoding antigens recognized during human visceral leishmaniasis. 294 Apr 61

A lambda gt11 expression library was constructed using mRNA from the promastigote form of Leishmania donovani (African isolate MHOM/ET/67/HU3). The library was screened with serum obtained from a patient who contracted visceral leishmaniasis in the Sudan. Several cDNA clones which expressed beta-galactosidase/L. donovani antigen fusion proteins were isolated. One of these clones corresponded to a 60 kDa membrane-associated antigen. By a Western blot assay antibodies against the fusion protein were detected universally in the sera of visceral leishmaniasis patients. They were not detected in sera from patients with cutaneous leishmaniasis or other parasitic protozoan infections. The gene coding for this antigen was specific to the genus Leishmania as judged by DNA hybridisation, and its chromosomal location was conserved. A 20 kb mRNA was detected on Northern blots of promastigote RNA.
Mol Biochem Parasitol 1988 Sep
PMID:Specific serodiagnosis of visceral leishmaniasis using a Leishmania donovani antigen identified by expression cloning. 297 29


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