Search results for "amoeba"
showing 10 items of 40 documents
Hybrid QM/MM Molecular Dynamics with AMOEBA Polarizable Embedding
2017
International audience; We present the implementation of a Born-Oppenheimer (BO) hybrid Quantum Mechan-ics/Molecular Mechanics (QM/MM) Molecular Dynamics (MD) strategy using Density Functional Theory (DFT) and the polarizable AMOEBA force field. This approach couples the Gaussian and Tinker suite of programs through a variational formalism allowing for a full self-consistent relaxation of both the AMOEBA induced dipoles and the DFT electronic density at each MD step. As the DFT SCF cycles are the limiting factor in terms of computational efforts and MD stability, we focus on the latter aspect and compare the Time-Reversible BO (TR– BO) and the Extended BO Lagrangian approaches (XL–BO) to th…
Trapping the Enemy: Vermamoeba vermiformis Circumvents Faustovirus Mariensis Dissemination by Enclosing Viral Progeny inside Cysts
2019
Viruses depend on cells to replicate and can cause considerable damage to their hosts. However, hosts have developed a plethora of antiviral mechanisms to counterattack or prevent viral replication and to maintain homeostasis. Advantageous features are constantly being selected, affecting host-virus interactions and constituting a harsh race for supremacy in nature. Here, we describe a new antiviral mechanism unveiled by the interaction between a giant virus and its amoebal host. Faustovirus mariensis infects Vermamoeba vermiformis, a free-living amoeba, and induces cell lysis to disseminate into the environment. Once infected, the cells release a soluble factor that triggers the encystment…
Tailoring a pair of pants
2021
Abstract We show how to deform the map Log : ( C ⁎ ) n → R n such that the image of the complex pair of pants P ∘ ⊂ ( C ⁎ ) n is the tropical hyperplane by showing an (ambient) isotopy between P ∘ ⊂ ( C ⁎ ) n and a natural polyhedral subcomplex of the product of the two skeleta S × Σ ⊂ A × C of the amoeba A and the coamoeba C of P ∘ . This lays the groundwork for having the discriminant to be of codimension 2 in topological Strominger-Yau-Zaslow torus fibrations.
<em>In vitro</em> tRNA Methylation Assay with the <em>Entamoeba histolytica</em> DNA and tRNA Methyltransferase Dnmt2 (Ehmeth…
2010
Protozoan parasites are among the most devastating infectious agents of humans responsible for a variety of diseases including amebiasis, which is one of the three most common causes of death from parasitic disease. The agent of amebiasis is the amoeba parasite Entamoeba histolytica that exists under two stages: the infective cyst found in food or water and the invasive trophozoite living in the intestine. The clinical manifestations of amebiasis range from being asymptomatic to colitis, dysentery or liver abscesses. E. histolytica is one of the rare unicellular parasite with 5-methylcytosine (5mC) in its genome. 1, 2 It contains a single DNA methyltransferase, Ehmeth, that belongs to the D…
Acanthamoeba isolates belonging to T1, T2, T3, T4 and T7 genotypes from environmental freshwater samples in the Nile Delta region, Egypt.
2006
The free-living amoebae of the genus Acanthamoeba include non-pathogenic and pathogenic species and has been recently classified into 15 different genotypes, T1–T15. In this study, a survey was conducted in order to determine the presence and pathogenic potential of free-living amoebae of Acanthamoeba genus in freshwater sources associated with human activities in the Nile Delta region, Egypt. Identification of Acanthamoeba was based on the morphology of cyst and trophozoite forms and PCR amplification with a genus specific primer pair. The pathogenic potential of Acanthamoeba isolates was characterized using temperature and osmotolerance assays and PCR reactions with two primer pairs speci…
Presence of very high prevalence and intensity of infection with Fasciola hepatica among Aymara children from the Northern Bolivian Altiplano.
1997
Abstract Coprological studies of school children from four communities in the Northern Bolivian Altiplano were carried out in order to estimate the prevalences and intensities of Fasciola hepatica infection. Single stool specimens were collected at random from 558 school children (308 boys and 250 girls) aged 5–19 years old. Nineteen different parasite species (13 protozoan and six helminths) were detected. Of the children examined, 98.7% (96.5–100%) presented infection with at least one parasite species. The mean prevalence of 27.6% by Fasciola hepatica (range, 5.9–38.2%) was the highest not only with respect to the helminth species found in the Northern Bolivian Altiplano but also among t…
Binding to complement factors and activation of the alternative pathway by Acanthamoeba.
2010
Acanthamoeba can cause severe ocular and cerebral diseases in healthy and immunocompromised individuals, respectively. Activation of complement appears to play an important role in host defence against infection. The exact mechanism, however, is still unclear. The aim of the present study was to investigate the effect of normal human serum (NHS) and normal mouse serum (NMS) on Acanthamoeba trophozoites, the binding of different complement factors to Acanthamoeba and the activation of the complement system. Moreover, we aimed to work out any possible differences between different strains of Acanthamoeba. A virulent T4 strain, a non-virulent T4 strain and a virulent T6 strain were included in…
Prevalence of intestinal parasites among inmates in Midwest Brazil.
2017
Made available in DSpace on 2018-11-26T17:40:54Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-09-21 Fundacao de Desenvolvimento, Ensino, Ciencia e Tecnologia do Estado de Mato Grosso do Sul (FUNDECT) Background Intestinal parasitic infections constitute a public health issue in developing countries, with prevalence rates as high as 90%, a figure set to escalate as the socioeconomic status of affected populations deteriorates. Investigating the occurrence of these infections among inmates is critical, since this group is more vulnerable to the spread of a number of infectious illnesses. Methods This cross-sectional, analytical, quantitative study was conducted in July 2015 at prison…
A New Nuclear Function of the Entamoeba histolytica Glycolytic Enzyme Enolase: The Metabolic Regulation of Cytosine-5 Methyltransferase 2 (Dnmt2) Act…
2009
Cytosine-5 methyltransferases of the Dnmt2 family function as DNA and tRNA methyltransferases. Insight into the role and biological significance of Dnmt2 is greatly hampered by a lack of knowledge about its protein interactions. In this report, we address the subject of protein interaction by identifying enolase through a yeast two-hybrid screen as a Dnmt2-binding protein. Enolase, which is known to catalyze the conversion of 2-phosphoglycerate (2-PG) to phosphoenolpyruvate (PEP), was shown to have both a cytoplasmatic and a nuclear localization in the parasite Entamoeba histolytica. We discovered that enolase acts as a Dnmt2 inhibitor. This unexpected inhibitory activity was antagonized by…
One Health Approach to Zoonotic Parasites: Molecular Detection of Intestinal Protozoans in an Urban Population of Norway Rats, Rattus norvegicus, in …
2021
Rattus norvegicus, the brown or Norway rat, is the most abundant mammal after humans in urban areas, where they live in close proximity to people. Among rodent-borne diseases, the reservoir role of Norway rats of zoonotic parasites in cities has practically been ignored. Considering the parasitic diseases in the One Health approach, we intended to identify and quantify the zoonotic intestinal protozoans (ZIP) in an urban population of R. norvegicus in the city of Barcelona, Spain. We studied the presence of ZIP in 100 rats trapped in parks (n = 15) as well as in the city’s sewage system (n = 85) in the winter of 2016/17. The protozoans were molecularly identified by means of a multiplex PCR…