Search results for "Host"

Host-Guest Interactions of Sodiumsulfonatomethyleneresorcinarene and Quaternary Ammonium Halides : An Experimental-Computational Analysis of the Gues…

2020

The molecular recognition of nine quaternary alkyl- and aryl-ammonium halides (Bn) by two different receptors, Calkyl-tetrasodiumsulfonatomethyleneresorcinarene (An), were studied in solution using 1H NMR spectroscopy. Substitution of methylenesulfonate groups at 2-positions of resorcinol units resulted in an increase of cavity depth by ∼2.80 Å and a narrow cavity aperture compared to Calkyl-2-H-resorcinarenes. The effect of alkyl chain lengths on the endo-complexation, that is the ability to incorporate other than N-methyl chains inside the cavities, were investigated using ammonium cations of the type ⁺NH2(R1)(R2), (R1 = Me, Et, Bu, R2 = Bu, Ph, Bz ). The C−H⋯ interactions between guests …

Recognition of alkali metal halide contact ion pairs by uranyl-salophen receptors bearing aromatic sidearms. The role of cation-pi interactions.

2005

Hard anions have long been known to bind strongly to the uranium of uranyl-salophen complexes. Upon functionalization of the salophen framework with one or two benzyloxy substituents, efficient ditopic receptors for alkali metal ions are obtained. The solid-state structures of complexes formed by the two-armed receptor 1 with CsF and with the chlorides of K+, Rb+, and Cs+ reported here reveal the existence of dimeric supramolecular assemblies in which two receptor units assemble into capsules fully enclosing (MX)2 ion quartets. In addition to the strong coordinative binding of the anion to the uranyl center and to electrostatic cation-anion interactions, stabilizing interactions arise from …

Divergent parasite infections in sympatric cichlid species in Lake Victoria

2018

Parasitism has been proposed as a factor in host speciation, as an agent affecting coexistence of host species in species‐rich communities and as a driver of post‐speciation diversification. Young adaptive radiations of closely related host species of varying ecological and genomic differentiation provide interesting opportunities to explore interactions between patterns of parasitism, divergence and coexistence of sympatric host species. Here, we explored patterns in ectoparasitism in a community of 16 fully sympatric cichlid species at Makobe Island in Lake Victoria, a model system of vertebrate adaptive radiation. We asked whether host niche, host abundance or host genetic differentiatio…

Experimental approaches to study the transmission and infection of Cardiocephaloides longicollis (Rudolphi, 1819) Dubois, 1982 (Trematoda, Strigeidae…

2023

Los trematodos (Platyhelminthes, Trematoda) son componentes ubicuos de los ecosistemas y, en las últimas décadas, los investigadores han mostrado un interés creciente en ellos, especialmente en sus estrategias y mecanismos de transmisión e infección. Los digeneos forman un grupo grande y generalmente tienen un ciclo de vida complejo con tres huéspedes. El primer huésped intermedio suele ser un molusco, el segundo huésped intermedio puede ser un huésped invertebrado o vertebrado, y el huésped definitivo suele ser un vertebrado. En el huésped definitivo, el parásito se convierte en adulto y se reproduce sexualmente. Luego, los huevos del parásito se liberan en el medio ambiente donde el mirac…

Establishment and interspecific associations in two species of Ichthyocotylurus (Trematoda) parasites in perch (Perca fluviatilis)

2011

Background: Co-infections of multiple parasite species in hosts may lead to interspecific associations and subsequently shape the structure of a parasite community. However, few studies have focused on these associations in highly abundant parasite species or, in particular, investigated how the associations develop with time in hosts exposed to co-infecting parasite species for the first time. We investigated metacercarial establishment and interspecific associations in the trematodes Ichthyocotylurus variegatus and I. pileatus co-infecting three age cohorts of young perch (Perca fluviatilis). Results: We found that the timing of transmission of the two Ichthyocotylurus species was very si…

Preceding Host History of Conjugative Resistance Plasmids Affects Intra- and Interspecific Transfer Potential from Biofilm

2023

Conjugative plasmids can confer antimicrobial resistance (AMR) to their host bacterium. The plasmids disperse even between distantly related host species, rescuing the host from otherwise detrimental effects of antibiotics. Little is known about the role of these plasmids in the spread of AMR during antibiotic treatment. One unstudied question is whether the past evolutionary history of a plasmid in a particular species creates host specificity in its rescue potential or if interspecific coevolution can improve interspecific rescues. To study this, we coevolved the plasmid RP4 under three different host settings; solely Escherichia coli or Klebsiella pneumoniae, or alternating between both …

Selective recognition of aromatic hydrocarbons by endo-functionalized molecular tubes via C/N-H⋅⋅⋅π interactions

2018

Molecular recognition of aromatic hydrocarbons by four endo-functionalized molecular tubes has been studied by 1H NMR spectroscopy, computational methods, and single crystal X-ray crystallography. The binding selectivity is rationalized by invoking shape complementarity and dipole alignment. The non-covalent interactions are proved to predominantly be C/N-H⋅⋅⋅π interactions. peerReviewed

The role of immigrants' self identity in effective integration process into Finland

2016

The purpose of this research is to study the role of immigrants’ identity in the process of effective integration into Finland. The research questions of the study explore (a) individual perceptions of self identity and effective integration into the host society from immigrants’ perspectives, (b) the impact of the integration process on immigrants’ self identity and (c) the identity changes of immigrants during the process of integration into the host society. Semi-structured in-depth interviews were conducted with six participants in Jyväskylä, Finland in order to best capture immigrants’ diverse life experiences reflecting identity issues during the integration process into the host soci…

Liikuntaharjoittelun vaikutus iäkkäiden henkilöiden päivittäisistä toiminnoista selviytymiseen : kontrolloitu tutkimus

2000

The role of maternal effects in host-parasite interactions: examination of the development of the immune defense in a colonial seabird, the black-leg…

2004

One of the main aims of evolutionary biology is to understand the mechanisms responsible for the phenotypic variation on which natural selection can act. Maternal effects occur when a mother's phenotype or her environment influence her offspring's phenotype. Despite the importance of such effects for the ecology of host-parasite interactions, their role has been relatively neglected to date. In this thesis, we examined how mothers influence the immune defense of their young in an environment that varies in space and time. This work has primarily focused on a colonial seabird, the black-legged kittiwake (Rissa tridactyla). Using this model, we have first shown that specific maternal antibodi…