Search results for "host"

Oral verruciform xanthoma and erythroplakia associated with chronic graft-versus-host disease: A rare case report and review of the literature

2017

Abstract Background Oral verruciform xanthoma is an uncommon benign lesion. Although oral verruciform xanthoma occurs in healthy individuals, it has been also reported in association with some inflammatory conditions. The aim of this study is to report a case of oral verruciform xanthoma associated with chronic graft-versus-host disease and to review the literature on this topic. Case presentation A 47-year-old Caucasian male presented to the Sector of Oral Medicine “V. Margiotta”, University Policlinic “P. Giaccone” of Palermo complaining of a mass on the gingiva. He first noticed the painless mass 1 year ago. He reported to have undergone allogenic hematopoietic stem cell transplantation …

Defects in plant immunity modulate the rates and patterns of RNA virus evolution

2020

AbstractIt is assumed that host genetic variability for susceptibility to infection necessarily conditions virus evolution. Differences in host susceptibility can either drive the virus to diversify into strains that track different defense alleles (e.g., antigenic diversity) or to infect only the most susceptible genotypes. To clarify these processes and their effect on virulence, we have studied how variability in host defense responses determine the evolutionary fate of viruses. To accomplish this, we performed evolution experiments with Turnip mosaic potyvirus in Arabidopsis thaliana mutants. Mutant plants had disruptions in infection-response signaling pathways or in genes whose produc…

Larval morphology, genetic divergence, and contrasting levels of host manipulation between forms of Pomphorhynchus laevis (Acanthocephala)

2004

Studies on parasite species with a wide geographic and ecological range may be confounded by still equivocal taxonomic identification. Here, we investigated genetic polymorphism and behavioural changes induced in a common intermediate host, in two different forms of Pomphorhynchus laevis based on the morphology of the larval infective stage (cystacanth). A 'smooth type' (S) and a 'wrinkled type' (W) of cystacanth were distinguished based on their surface and shape. We analysed sequence divergence at both nuclear (ribosomal gene 18S rDNA, and ribosomal internal transcribed spacers, ITS1/ITS2) and mitochondrial (cytochrome c oxidase subunit 1) genes of P. laevis cystacanths and adults at vari…

Conflict between co-occurring parasites as a confounding factor in manipulation studies?

2005

In their review, Thomas et al. (2005) highlight that, in cases where multiple infections occur in the same intermediate host individual, parasitic manipulation may be the result of not just a single parasite, but may be the cumulative effect of infection by two or more manipulating parasites. Such parasites may be in conflict when they share the same intermediate host but have different final hosts: they may manipulate the host in different ways in order to effect their different transmission p T c r s t s

Karyotypic diversity among Blastocystis hominis isolates

1997

Fifteen Blastocystis hominis strains, 13 axenic and 2 monoxenic, have been included in the present study. The chromosomal pattern was analyzed by the contour-clamped homogeneous electric-field (CHEF) system. The number of chromosomes detected ranged between 9 and 13, with sizes from 2200 kbp to 260 kbp. Eleven karyotypic profiles, with a common pattern constituted by 8 chromosomes of 2200, 1280, 890, 840, 700, 650, 540 and 260 kbp, were observed. The Jaccard index demonstrated that the similarity between isolates ranged from 0.5714 to 1. The different isolates were clustered in 3 karyotypes (A: 8 isolates; B: 6 isolates and C: 1 isolate). All isolates grouped in karyotype A presented a char…

2015

Bracoviruses are symbiotic viruses associated with tens of thousands of species of parasitic wasps that develop within the body of lepidopteran hosts and that collectively parasitize caterpillars of virtually every lepidopteran species. Viral particles are produced in the wasp ovaries and injected into host larvae with the wasp eggs. Once in the host body, the viral DNA circles enclosed in the particles integrate into lepidopteran host cell DNA. Here we show that bracovirus DNA sequences have been inserted repeatedly into lepidopteran genomes, indicating this viral DNA can also enter germline cells. The original mode of Horizontal Gene Transfer (HGT) unveiled here is based on the integrativ…

EXPERIMENTAL EVOLUTION OF AN EMERGING PLANT VIRUS IN HOST GENOTYPES THAT DIFFER IN THEIR SUSCEPTIBILITY TO INFECTION

2014

This study evaluates the extent to which genetic differences among host individuals from the same species condition the evolution of a plant RNA virus. We performed a threefold replicated evolution experiment in which Tobacco etch potyvirus isolate At17b (TEV-At17b), adapted to Arabidopsis thaliana ecotype Ler-0, was serially passaged in five genetically heterogeneous ecotypes of A. thaliana. After 15 passages we found that evolved viruses improved their fitness, showed higher infectivity and stronger virulence in their local host ecotypes. The genome of evolved lineages was sequenced and putative adaptive mutations identified. Host-driven convergent mutations have been identified. Evidence…

A genetic background with low mutational robustness is associated with increased adaptability to a novel host in an RNA virus.

2009

Although mutational robustness is central to many evolutionary processes, its relationship to evolvability remains poorly understood and has been very rarely tested experimentally. Here, we measure the evolvability of Vesicular stomatitis virus in two genetic backgrounds with different levels of mutational robustness. We passaged the viruses into a novel cell type to model a host-jump episode, quantified changes in infectivity and fitness in the new host, evaluated the cost of adaptation in the original host and analyzed the genetic basis of this adaptation. Lineages evolved from the less robust genetic background demonstrated increased adaptability, paid similar costs of adaptation to the …

Horizontal gene transfer to a defensive symbiont with a reduced genome amongst a multipartite beetle microbiome

2019

ABSTRACTThe loss of functions required for independent life when living within a host gives rise to reduced genomes in obligate bacterial symbionts. Although this phenomenon can be explained by existing evolutionary models, its initiation is not well understood. Here, we describe the microbiome associated with eggs of the beetleLagria villosa, containing multiple bacterial symbionts related toBurkholderia gladioliincluding a reduced-genome symbiont thought to produce the defensive compound lagriamide. We find that the putative lagriamide producer is the only symbiont undergoing genome reduction, and that it has already lost most primary metabolism and DNA repair pathways. The horizontal acq…

A genome-wide association study identifies Arabidopsis thaliana genes that contribute to differences in the outcome of infection with two Turnip mosa…

2021

Viruses lie in a continuum between generalism and specialism depending on their ability to infect more or less hosts. While generalists are able to successfully infect a wide variety of hosts, specialists are limited to one or a few. Even though generalists seem to gain an advantage due to their wide host range, they usually pay a pleiotropic fitness cost within each host. On the contrary, a specialist has maximal fitness within its own host. A relevant yet poorly explored question is whether viruses differ in the way they interact with their hosts’ gene expression depending on their degree of specialization. Using a genome-wide association study approach, we have identified host genes whos…