scholarly journals On the evolution of host specificity: a case study of helminths

2021 ◽  
Author(s):  
Alaina C. Pfenning-Butterworth ◽  
Sebastian Botero-Cañola ◽  
Clayton E. Cressler

ABSTRACTThe significant variation in host specificity exhibited by parasites has been separately linked to evolutionary history and ecological factors in specific host-parasite associations. Yet, whether there are any general patterns in the factors that shape host specificity across parasites more broadly is unknown. Here we constructed a molecular phylogeny for 249 helminth species infecting free-range mammals and find that the influence of ecological factors and evolutionary history varies across different measures of host specificity. Whereas the phylogenetic range of hosts a parasite can infect shows a strong signal of evolutionary constraint, the number of hosts a parasite infects does not. Our results shed new light on the evolution of host specificity in parasites, suggesting that phylogenetic breadth may capture the evolutionary potential of a parasite to jump between hosts, whereas the number of hosts may reflect ecological opportunity. Finally, we show parasite phylogenies can also provide an alternative perspective on zoonosis by identifying which hosts are infected by a broad phylogenetic range of parasites.

Parasitology ◽  
1929 ◽  
Vol 21 (3) ◽  
pp. 227-255 ◽  
Author(s):  
J. H. Sandground

1.The relation of host-parasite specificity to age resistance.Conclusive demonstration of a substantial resistance developing concomitantly with the ageing of the host has been made with reference to four helminths, namely: Ancylostoma duodenale andA. caninumin the dog andAscaridia lineataandSyngamus tracheain the chicken.A. duodenalein the dog andS. tracheain the chicken are manifestly in abnormal hosts. In contrast with this, it is to be noted that the normal hosts of these parasites, respectively man and the turkey, exhibit no appreciable age resistance. With regard to the remaining two cases, those ofAncylostoma caninumandAscaridia lineata, the association of age resistance and a specific host-parasite mal-adjustment is not nearly so clear. In nature, both parasites enjoy a polyxenous distribution, neither having acquired the need for strictly specific host conditions for development. As a result of recent researches withA. caninumit has been brought out that the species is comprised of strains better adapted to one species of host than to another, and it has been demonstrated that a higher degree of age resistance is exhibited in the host parasitised with a foreign strain. Although no information on the matter is available, it is quite possible that age resistance will be found to be less markedly expressed in other species or races of suitable hosts, when the bionomics of bothAncylostoma caninumandAscaridia lineataare further investigated.


1967 ◽  
Vol 24 (10) ◽  
pp. 2161-2168 ◽  
Author(s):  
Hisao P. Arai

An investigation of the relative roles of phylogenetic and ecological factors in determining host specificity at the intrafamilial level in fishes of the family Embiotocidae has been made. The results do not show indications that specificity is related to host phylogeny, i.e. parallel host–parasite evolution is not apparent. However, data are presented which strongly support the contention that specificity of parasites in Cymatogaster aggregata is determined by factors which are of an ecological nature.


2016 ◽  
Vol 18 (1) ◽  
pp. 181-196 ◽  
Author(s):  
A. Mouton ◽  
A. Mortelliti ◽  
A. Grill ◽  
M. Sara ◽  
B. Kryštufek ◽  
...  

2021 ◽  
pp. 1-79
Author(s):  
Alin G. Chitu ◽  
Mart H. A. A. Zijp ◽  
Jonathan Zwaan

The fundamental assumption of many successful geochemical and geomicrobial technologies developed in the last 80 years is that hydrocarbons leak from subsurface accumulations vertically to the surface. Driven by buoyancy, the process involves sufficiently large volumes directly measurable or indirectly inferable from their surface expressions. Even when the additional hydrocarbons are not measurable, their presence slightly changes the environment, where complex microbial communities live, and acts as an evolutionary constraint on their development. Since the ecology of this ecosystem is very complicated, we propose to use the full-microbiome analysis of the shallow sediments samples instead of targeting a selected number of known species, and the use of machine learning for uncovering the meaningful correlations in these data. We achieve this by sequencing the microbial biomass and generating its “DNA fingerprint”, and by analyzing the abundance and distribution of the microbes over the dataset. The proposed technology uses machine learning as an accurate tool for determining the detailed interactions among the various microorganisms and their environment in the presence or absence of hydrocarbons, thus overcoming data complexity. In a proof-of-technology study, we have taken more than 1000 samples in the Neuqu謠Basin in Argentina over three distinct areas, namely, an oil field, a gas field, and a dry location outside the basin, and created several successful predictive models. A subset of randomly selected samples was kept outside of the training set and blinded by the client operator, providing the means for objectively validating the prediction performance of this methodology. Uncovering the blinded dataset after estimating the prospectivity revealed that most of these samples were correctly predicted. This very encouraging result shows that analyzing the microbial ecosystem in the shallow sediment can be an additional de-risking method for assessing hydrocarbon prospects and improving the Probability Of Success(POS) of a drilling campaign.


PLoS ONE ◽  
2009 ◽  
Vol 4 (10) ◽  
pp. e7621 ◽  
Author(s):  
Carolyn Riddell ◽  
Sally Adams ◽  
Paul Schmid-Hempel ◽  
Eamonn B. Mallon

In the modern context of, one of the main tasks in the regional development management is to optimally realize the complex potential of the territories, which requires a comprehensive study of the spatial structure and evolutionary potential of agglomerations of all levels in order to identify disparities in their development, correct imbalances and optimize the spatial organization of the region. The first step to solve this problem is to identify the spatial structure and evaluate the interconnections of agglomerations sequentially, from local to regional level. This is becoming more relevant in the context of administrative and territorial reform in Ukraine. The purpose of this study is to analyze the prospects for the development of urban agglomerations and the organization of the administrative and territorial structure of Kharkiv region in view of the prevailing influence of the city of Kharkiv and the Kharkiv agglomeration. The basic theoretical and methodological starting points of the study of urban agglomerations are presented; their characteristics and parameters of boundary determination were defined. The essence of the method of modeling of integral influence function (IIF modeling) was revealed, the author's research methodology was substantiated. The tendencies of introduction of administrative and territorial reform in Ukraine were analyzed. It was established that Kharkiv region occupies mediocre places in terms of formation of the united territorial communities, there were 23 ones in the oblast (3 of them are city, 12 town, 8 rural ones) by the end of 2019. The scheme for dividing into enlarged districts has not yet been approved. According to different plans / proposals, the existing 27 districts of the oblast should be consolidated into nine, seven, six or four enlarged districts (counties). All of the above proposals were considered by the authors, it is established that the existing projects do not fully cover the main prevailing factors of allocation of competitive districts, do not take into account the role of historically formed system of settlement, spatial-statistical parameters, integral potential of territories, urbanization and agglomeration. The authors performed the IIF modeling and constructed the IIF surface of the weighted average settlement potential of Kharkiv region by the base radius of influence (2, 10, 20, and 30 km), which allowed to determine the features of the Kharkov agglomeration structure and the interaction of the settlements in the region by different radiuses of interaction, primary agglomerations, prospective growth points. On the basis of the obtained results of IIF modeling, the author's model of administrative and territorial division of Kharkiv region into eight enlarged districts was proposed, given the specific features of the settlement system and the correlation of area and population of the modeled administrative and territorial units. The scientifically grounded division of the region into enlarged districts (counties) and stimulation of their development will contribute to the most complete and rational use of the territories potential, increase of economic, human, investment potential, rise of the level and quality of life of the population, etc.


2016 ◽  
Vol 21 ◽  
pp. 16-23 ◽  
Author(s):  
M. Schnittler ◽  
N.H.A. Dagamac ◽  
M. Sauke ◽  
M. Wilmking ◽  
A. Buras ◽  
...  
Keyword(s):  

PLoS ONE ◽  
2018 ◽  
Vol 13 (9) ◽  
pp. e0204365 ◽  
Author(s):  
Rafael Molina-Venegas ◽  
Sonia Llorente-Culebras ◽  
Paloma Ruiz-Benito ◽  
Miguel A. Rodríguez

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