Bates, David W* Dotaz Zobrazit nápovědu

Leishmania parasites, causative agents of leishmaniasis, are currently divided into four subgenera: Leishmania, Viannia, Sauroleishmania and Mundinia. The recently established subgenus Mundinia has a wide geographical distribution and contains five species, three of which have the potential to infect and cause disease in humans. While the other Leishmania subgenera are transmitted exclusively by phlebotomine sand flies (Diptera: Psychodidae), natural vectors of Mundinia remain uncertain. This study investigates the potential of sand flies and biting midges of the genus Culicoides (Diptera: Ceratopogonidae) to transmit Leishmania parasites of the subgenus Mundinia. Sand flies (Phlebotomus argentipes, P. duboscqi and Lutzomyia migonei) and Culicoides biting midges (Culicoides sonorensis) were exposed to five Mundinia species through a chicken skin membrane and dissected at specific time intervals post bloodmeal. Potentially infected insects were also allowed to feed on ear pinnae of anaesthetized BALB/c mice and the presence of Leishmania DNA was subsequently confirmed in the mice using polymerase chain reaction analyses. In C. sonorensis, all Mundinia species tested were able to establish infection at a high rate, successfully colonize the stomodeal valve and produce a higher proportion of metacyclic forms than in sand flies. Subsequently, three parasite species, L. martiniquensis, L. orientalis and L. sp. from Ghana, were transmitted to the host mouse ear by C. sonorensis bite. In contrast, transmission experiments entirely failed with P. argentipes, although colonisation of the stomodeal valve was observed for L. orientalis and L. martiniquensis and metacyclic forms of L. orientalis were recorded. This laboratory-based transmission of Mundinia species highlights that Culicoides are potential vectors of members of this ancestral subgenus of Leishmania and we suggest further studies in endemic areas to confirm their role in the lifecycles of neglected pathogens.

Článek

Comparative genomics of Leishmania (Mundinia)

In addition, it is interesting from the evolutionary viewpoint, representing the earliest branch within ...

BMC genomics. 2019 ; 20 (1) : 726. [pub] 20191011

BMC Genomics
ISSN 1471-2164
Medvik
Zdroj

BACKGROUND: Trypanosomatids of the genus Leishmania are parasites of mammals or reptiles transmitted by bloodsucking dipterans. Many species of these flagellates cause important human diseases with clinical symptoms ranging from skin sores to life-threatening damage of visceral organs. The genus Leishmania contains four subgenera: Leishmania, Sauroleishmania, Viannia, and Mundinia. The last subgenus has been established recently and remains understudied, although Mundinia contains human-infecting species. In addition, it is interesting from the evolutionary viewpoint, representing the earliest branch within the genus and possibly with a different type of vector. Here we analyzed the genomes of L. (M.) martiniquensis, L. (M.) enriettii and L. (M.) macropodum to better understand the biology and evolution of these parasites. RESULTS: All three genomes analyzed were approximately of the same size (~ 30 Mb) and similar to that of L. (Sauroleishmania) tarentolae, but smaller than those of the members of subgenera Leishmania and Viannia, or the genus Endotrypanum (~ 32 Mb). This difference was explained by domination of gene losses over gains and contractions over expansions at the Mundinia node, although only a few of these genes could be identified. The analysis predicts significant changes in the Mundinia cell surface architecture, with the most important ones relating to losses of LPG-modifying side chain galactosyltransferases and arabinosyltransferases, as well as β-amastins. Among other important changes were gene family contractions for the oxygen-sensing adenylate cyclases and FYVE zinc finger-containing proteins. CONCLUSIONS: We suggest that adaptation of Mundinia to different vectors and hosts has led to alternative host-parasite relationships and, thereby, made some proteins redundant. Thus, the evolution of genomes in the genus Leishmania and, in particular, in the subgenus Mundinia was mainly shaped by host (or vector) switches.

MeSH
délka genomu MeSH
fylogeneze MeSH
genomika MeSH
hostitelská specificita MeSH
Leishmania klasifikace genetika MeSH
molekulární evoluce MeSH
ploidie MeSH
protozoální proteiny genetika MeSH
regulace genové exprese MeSH
sekvenování celého genomu metody MeSH
sekvenování exomu MeSH
stanovení celkové genové exprese metody MeSH
Publikační typ
časopisecké články MeSH

Článek

Effect of natalizumab on clinical and radiological disease activity in multiple sclerosis: a retrospective analysis of the Natalizumab Safety and Efficacy in Relapsing-Remitting Multiple Sclerosis (AFFIRM) study

Efficacy in Relapsing-Remitting Multiple Sclerosis (AFFIRM) study has prompted the investigation of whether ...

Lancet neurology. 2009 ; 8 (3) : 254-260.

Lancet Neurol
ISSN 1474-4422
Medvik
Zdroj

BACKGROUND: The efficacy of natalizumab on clinical and radiological measures in the phase III Natalizumab Safety and Efficacy in Relapsing-Remitting Multiple Sclerosis (AFFIRM) study has prompted the investigation of whether natalizumab can increase the proportion of patients with relapsing-remitting multiple sclerosis who do not have disease activity. METHODS: Post-hoc analyses of data from the AFFIRM study were done to determine the effects of natalizumab compared with placebo on the proportion of patients who were free of disease activity over 2 years. Absence of disease activity was defined as no activity on clinical measures (no relapses and no sustained disability progression), radiological measures (no gadolinium-enhancing lesions and no new or enlarging T2-hyperintense lesions on cranial MRI), or a composite of the two. FINDINGS: 383 (64%) of 596 patients taking natalizumab and 117 (39%) of 301 taking placebo were free of clinical disease activity (absolute difference 25.4%, 95% CI 18.7-32.1%, p<0.0001); 342 (58%) of 593 and 42 (14%) of 296 were free of radiological disease activity (43.5%, 37.9-49.1%, p<0.0001); and 220 (37%) of 600 and 22 (7%) of 304 were free of combined activity (29.5%, 24.7-34.3%, p<0.0001) over 2 years. The effect of natalizumab versus placebo was consistent across subgroups of patients with highly active or non-highly active disease at baseline.

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Bates, David W* Dotaz Zobrazit nápovědu

Bates, David W* Dotaz Zobrazit nápovědu

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