High levels of genetic diversity inNosema ceranaewithinApis melliferacolonies

Parasitology ◽  
2013 ◽  
Vol 141 (4) ◽  
pp. 475-481 ◽  
Author(s):  
TAMARA GÓMEZ-MORACHO ◽  
XULIO MASIDE ◽  
RAQUEL MARTÍN-HERNÁNDEZ ◽  
MARIANO HIGES ◽  
CAROLINA BARTOLOMÉ
Keyword(s):  
Genetic Recombination ◽  
Population Expansion ◽  
Single Copy ◽  
Recent Population Expansion ◽  
Colony Losses ◽  
Bee Colony ◽  
Host Parasite Interactions ◽  
Recent Origin ◽  
Different Strains ◽  
Host Parasite

SUMMARYNosema ceranaeis a widespread honeybee parasite, considered to be one of the pathogens involved in the colony losses phenomenon. To date, little is known about its intraspecific genetic variability. The few studies onN. ceranaevariation have focused on the subunits of ribosomal DNA, which are not ideal for this purpose and have limited resolution. Here we characterized three single copy loci (Actin, Hsp70andRPB1) in threeN. ceranaeisolates from Hungary and Hawaii. Our results provide evidence of unexpectedly high levels of intraspecific polymorphism, the coexistence of a wide variety of haplotypes within each bee colony, and the occurrence of genetic recombination inRPB1. Most haplotypes are not shared across isolates and derive from a few frequent haplotypes by a reduced number of singletons (mutations that appear usually just once in the sample), which suggest that they have a fairly recent origin. Overall, our data indicate that this pathogen has experienced a recent population expansion. The presence of multiple haplotypes within individual isolates could be explained by the existence of different strains ofN. ceranaeinfecting honeybee colonies in the field which complicates, and must not be overlooked, further analysis of host–parasite interactions.

Evolution and function of tandem repeats in the major surface protein 1a of the ehrlichial pathogenAnaplasma marginale

2001 ◽  
Vol 2 (2) ◽  
pp. 163-174 ◽  
Author(s):  
José de la Fuente ◽  
Jose C. Garcia-Garcia ◽  
Edmour F. Blouin ◽  
Sergio D. Rodríguez ◽  
Migel A. García ◽  
...  
Keyword(s):  
Tandem Repeats ◽  
Control Strategies ◽  
Surface Protein ◽  
Single Copy ◽  
Major Surface Protein ◽  
Host Parasite Interactions ◽  
Major Surface ◽  
And Function ◽  
Host Parasite ◽  
Bovine Erythrocytes

AbstractThe major surface protein (MSP) 1a of the ehrlichial cattle pathogenAnaplasma marginale, encoded by the single-copy genemsp1α, has been shown to have a neutralization-sensitive epitope and to be an adhesin for bovine erythrocytes and tick cells.msp1αhas been found to be a stable genetic marker for the identification of geographic isolates ofA. marginalethroughout development in acutely and persistently infected cattle and in ticks. The molecular weight of MSP1a varies among geographic isolates ofA. marginalebecause of a varying number of tandemly repeated peptides of 28–29 amino acids. Variation in the sequence of the tandem repeats occurs within and among isolates, and may have resulted from evolutionary pressures exerted by ligand–receptor and host–parasite interactions. These repeated sequences include markers for tick transmissibility that may be important in the identification of ehrlichial pathogens because they may influence control strategies and the design of subunit vaccines.

scholarly journals Disentangling non-specific and specific transgenerational immune priming components in host–parasite interactions

2020 ◽  
Vol 287 (1920) ◽  
pp. 20192386
Author(s):  
Frida Ben-Ami ◽  
Christian Orlic ◽  
Roland R. Regoes
Keyword(s):  
Genetic Epidemiology ◽  
Ecological Systems ◽  
High Dose ◽  
Immune Priming ◽  
Specific Effects ◽  
Host Parasite Interactions ◽  
Pasteuria Ramosa ◽  
Different Strains ◽  
Host Parasite ◽  
First Time

Exposure to a pathogen primes many organisms to respond faster or more efficiently to subsequent exposures. Such priming can be non-specific or specific, and has been found to extend across generations. Disentangling and quantifying specific and non-specific effects is essential for understanding the genetic epidemiology of a system. By combining a large infection experiment and mathematical modelling, we disentangle different transgenerational effects in the crustacean model Daphnia magna exposed to different strains of the bacterial parasite Pasteuria ramosa . In the experiment, we exposed hosts to a high dose of one of three parasite strains, and subsequently challenged their offspring with multiple doses of the same (homologous) or a different (heterologous) strain. We find that exposure of Daphnia to Pasteuria decreases the susceptibility of their offspring by approximately 50%. This transgenerational protection is not larger for homologous than for heterologous parasite challenges. Methodologically, our work represents an important contribution not only to the analysis of immune priming in ecological systems but also to the experimental assessment of vaccines. We present, for the first time, an inference framework to investigate specific and non-specific effects of immune priming on the susceptibility distribution of hosts—effects that are central to understanding immunity and the effect of vaccines.

Comparative genetic diversity of Cryptosporidium species causing human infections

Parasitology ◽  
2020 ◽  
Vol 147 (13) ◽  
pp. 1532-1537 ◽  
Author(s):  
Juan C. Garcia-R ◽  
Murray P. Cox ◽  
David T. S. Hayman
Keyword(s):  
Genetic Diversity ◽  
Population Expansion ◽  
Recent Population Expansion ◽  
Cryptosporidium Hominis ◽  
High Genetic Diversity ◽  
Genetic Changes ◽  
Low Genetic Diversity ◽  
Human Infections ◽  
Host Parasite ◽  
Founder Events

AbstractParasites sometimes expand their host range and cause new disease aetiologies. Genetic changes can then occur due to host-specific adaptive alterations, particularly when parasites cross between evolutionarily distant hosts. Characterizing genetic variation in Cryptosporidium from humans and other animals may have important implications for understanding disease dynamics and transmission. We analyse sequences from four loci (gp60, HSP-70, COWP and actin) representing multiple Cryptosporidium species reported in humans. We predicted low genetic diversity in species that present unusual human infections due to founder events and bottlenecks. High genetic diversity was observed in isolates from humans of Cryptosporidium meleagridis, Cryptosporidium cuniculus, Cryptosporidium hominis and Cryptosporidium parvum. A deviation of expected values of neutrality using Tajima's D was observed in C. cuniculus and C. meleagridis. The high genetic diversity in C. meleagridis and C. cuniculus did not match our expectations but deviations from neutrality indicate a recent decrease in genetic variability through a population bottleneck after an expansion event. Cryptosporidium hominis was also found with a significant Tajima's D positive value likely caused by recent population expansion of unusual genotypes in humans. These insights indicate that changes in genetic diversity can help us to understand host-parasite adaptation and evolution.

scholarly journals Disentangling unspecific and specific transgenerational immune priming components in host-parasite interactions

2018 ◽  
Author(s):  
Frida Ben-Ami ◽  
Christian Orlic ◽  
Roland R. Regoes
Keyword(s):  
Bacterial Pathogen ◽  
Immune Memory ◽  
High Dose ◽  
Immune Priming ◽  
Host Parasite Interactions ◽  
Pasteuria Ramosa ◽  
Wide Range ◽  
Different Strains ◽  
Host Parasite ◽  
First Time

AbstractExposure to a pathogen primes many organisms to respond faster or more efficiently to subsequent exposures. Such priming can be unspecific or specific, and has been found to extend across generations. Disentangling and quantifying specific and unspecific effects is essential for understanding the genetic epidemiology of a system. By combining a large infection experiment and mathematical modeling, we disentangle different transgenerational effects in the crustacean model Daphnia magna exposed to different strains of the bacterial parasite Pasteuria ramosa. In the experiments, we exposed hosts to a high-dose of one of three parasite strains, and subsequently challenged their offspring with multiple doses of the same or a different strain, i. e. homologously or heterogously. We find that exposure to Pasteuria decreases the susceptibility of a host’s offspring by approximately 50%. This transgenerational protection is not larger for homologous than for heterologous parasite challenges. Our work represents an important contribution not only to the analysis of immune priming in ecological systems, but also to the experimental assessment of vaccines. We present for the first time an inference framework to investigate specific and unspecific effects of immune priming on the susceptibility distribution of hosts — effects that are central to understanding immunity and the effect of vaccines.Author summaryImmune memory is a feature of immune systems that forms the basis of vaccination. In opposition to textbook accounts, the ability to specifically remember previous exposures has been found to extend to invertebrates and shown to be able to be passed on from mother to off-spring, i. e. to be transgenerational. In this paper, we investigate the extent of this specificity in unprecedented detail in water fleas. We exposed water flea mothers to different strains of a bacterial pathogen and challenged their offspring with a wide range of doses of a strain that were either identical to (homologous) or different from (heterologous) the strain, to which the mother had been exposed. We find that, while exposure of the mother reduces the susceptibility of the offspring, this effect is not specific. This work outlines the limits of specific transgenerational immune memory in this invertebrate system.

Host parasite interactions and pathophysiology in Giardia infections

2011 ◽  
Vol 41 (9) ◽  
pp. 925-933 ◽  
Author(s):  
James A. Cotton ◽  
Jennifer K. Beatty ◽  
Andre G. Buret
Keyword(s):  
Host Parasite Interactions ◽  
Host Parasite

scholarly journals Population genetics of Aedes albopictus (Diptera: Culicidae) in its native range in Lao People’s Democratic Republic

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Maysa Tiemi Motoki ◽  
Dina Madera Fonseca ◽  
Elliott Frederic Miot ◽  
Bruna Demari-Silva ◽  
Phoutmany Thammavong ◽  
...  
Keyword(s):  
Population Structure ◽  
Gene Flow ◽  
Aedes Albopictus ◽  
Isolation By Distance ◽  
Genetic Locus ◽  
Lao Pdr ◽  
Phylogenetic Network ◽  
Population Expansion ◽  
Recent Population Expansion ◽  
The Usa

Abstract Background The Asian tiger mosquito, Aedes (Stegomyia) albopictus (Skuse) is an important worldwide invasive species and can be a locally important vector of chikungunya, dengue and, potentially, Zika. This species is native to Southeast Asia where populations thrive in both temperate and tropical climates. A better understanding of the population structure of Ae. albopictus in Lao PDR is very important in order to support the implementation of strategies for diseases prevention and vector control. In the present study, we investigated the genetic variability of Ae. albopictus across a north-south transect in Lao PDR. Methods We used variability in a 1337-bp fragment of the mitochondrial cytochrome c oxidase subunit 1 gene (cox1), to assess the population structure of Ae. albopictus in Lao PDR. For context, we also examined variability at the same genetic locus in samples of Ae. albopictus from Thailand, China, Taiwan, Japan, Singapore, Italy and the USA. Results We observed very high levels of genetic polymorphism with 46 novel haplotypes in Ae. albopictus from 9 localities in Lao PDR and Thailand populations. Significant differences were observed between the Luangnamtha population and other locations in Lao PDR. However, we found no evidence of isolation by distance. There was overall little genetic structure indicating ongoing and frequent gene flow among populations or a recent population expansion. Indeed, the neutrality test supported population expansion in Laotian Ae. albopictus and mismatch distribution analyses showed a lack of low frequency alleles, a pattern often seen in bottlenecked populations. When samples from Lao PDR were analyzed together with samples from Thailand, China, Taiwan, Japan, Singapore, Italy and the USA, phylogenetic network and Bayesian cluster analysis showed that most populations from tropical/subtropical regions are more genetically related to each other, than populations from temperate regions. Similarly, most populations from temperate regions are more genetically related to each other, than those from tropical/subtropical regions. Conclusions Aedes albopictus in Lao PDR are genetically related to populations from tropical/subtropical regions (i.e. Thailand, Singapore, and California and Texas in the USA). The extensive gene flow among locations in Lao PDR indicates that local control is undermined by repeated introductions from untreated sites.

scholarly journals The assembled and annotated genome of the pigeon louse Columbicola columbae, a model ectoparasite

2021 ◽  
Vol 11 (2) ◽  
Author(s):  
James G Baldwin-Brown ◽  
Scott M Villa ◽  
Anna I Vickrey ◽  
Kevin P Johnson ◽  
Sarah E Bush ◽  
...  
Keyword(s):  
Low Cost ◽  
Single Copy ◽  
Odorant Receptors ◽  
Rna Seq ◽  
Pediculus Humanus ◽  
Final Assembly ◽  
Oxford Nanopore ◽  
Genes Encoding ◽  
Host Parasite ◽  
G Protein Coupled

Abstract The pigeon louse Columbicola columbae is a longstanding and important model for studies of ectoparasitism and host-parasite coevolution. However, a deeper understanding of its evolution and capacity for rapid adaptation is limited by a lack of genomic resources. Here, we present a high-quality draft assembly of the C. columbae genome, produced using a combination of Oxford Nanopore, Illumina, and Hi-C technologies. The final assembly is 208 Mb in length, with 12 chromosome-size scaffolds representing 98.1% of the assembly. For gene model prediction, we used a novel clustering method (wavy_choose) for Oxford Nanopore RNA-seq reads to feed into the MAKER annotation pipeline. High recovery of conserved single-copy orthologs (BUSCOs) suggests that our assembly and annotation are both highly complete and highly accurate. Consistent with the results of the only other assembled louse genome, Pediculus humanus, we find that C. columbae has a relatively low density of repetitive elements, the majority of which are DNA transposons. Also similar to P. humanus, we find a reduced number of genes encoding opsins, G protein-coupled receptors, odorant receptors, insulin signaling pathway components, and detoxification proteins in the C. columbae genome, relative to other insects. We propose that such losses might characterize the genomes of obligate, permanent ectoparasites with predictable habitats, limited foraging complexity, and simple dietary regimes. The sequencing and analysis for this genome were relatively low cost, and took advantage of a new clustering technique for Oxford Nanopore RNAseq reads that will be useful to future genome projects.

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