scholarly journals Trade-offs shape the evolution of the vector-borne insect pathogen Xenorhabdus nematophila

2012 ◽  
Vol 279 (1738) ◽  
pp. 2672-2680 ◽  
Author(s):  
Élodie Chapuis ◽  
Audrey Arnal ◽  
Jean-Baptiste Ferdy
Keyword(s):  
Xenorhabdus Nematophila ◽  
Insect Pathogen ◽  
Trade Offs ◽  
Vector Borne

scholarly journals Virulence and Pathogen Multiplication: A Serial Passage Experiment in the Hypervirulent Bacterial Insect-Pathogen Xenorhabdus nematophila

PLoS ONE ◽  
2011 ◽  
Vol 6 (1) ◽  
pp. e15872 ◽  
Author(s):  
Élodie Chapuis ◽  
Sylvie Pagès ◽  
Vanya Emelianoff ◽  
Alain Givaudan ◽  
Jean-Baptiste Ferdy
Keyword(s):  
Serial Passage ◽  
Xenorhabdus Nematophila ◽  
Insect Pathogen

scholarly journals Trade-offs and mixed infections in an obligate-killing insect pathogen

2016 ◽  
Vol 85 (5) ◽  
pp. 1200-1209 ◽  
Author(s):  
Elizabeth M. Redman ◽  
Kenneth Wilson ◽  
Jenny S. Cory
Keyword(s):  
Mixed Infections ◽  
Insect Pathogen ◽  
Trade Offs

Novel insecticidal chitinase from the insect pathogen Xenorhabdus nematophila

2020 ◽  
Vol 159 ◽  
pp. 394-401
Author(s):  
Saquib Mahmood ◽  
Mukesh Kumar ◽  
Punam Kumari ◽  
Gagan Kumar Mahapatro ◽  
Nirupama Banerjee ◽  
...  
Keyword(s):  
Xenorhabdus Nematophila ◽  
Insect Pathogen

scholarly journals Step-specific adaptation and trade-off over the course of an infection by GASP-mutation small colony variants

2020 ◽  
Author(s):  
Faucher Christian ◽  
Mazana Vincent ◽  
Kardacz Marion ◽  
Parthuisot Nathalie ◽  
Ferdy Jean-Baptiste ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Chronic Phase ◽  
Infection Process ◽  
Infection Model ◽  
Xenorhabdus Nematophila ◽  
Trade Off ◽  
Small Colony Variants ◽  
Trade Offs ◽  
Small Colony ◽  
Host Evolution

AbstractDuring an infection, parasites face a succession of challenges, each decisive for disease outcome. The diversity of challenges requires a series of parasite adaptations to successfully multiply and transmit from host to host. Thus, the pathogen genotypes which succeed during one step might be counter-selected in later stages of the infection. Using the bacteria Xenorhabdus nematophila and adult Drosophila melanogaster as hosts, we showed that such step-specific adaptations, here linked to GASP mutations in the X. nematophila master gene regulator lrp, exist and can trade-off with each other. We found that nonsense lrp mutations had lowered ability to resist the host immune response, while all classes of mutations in lrp were associated with a decrease in the ability to proliferate during early infection. We demonstrate that reduced proliferation of X. nematophila best explains diminished virulence in this infection model. Finally, decreased proliferation during the first step of infection is accompanied with improved proliferation during late infection, suggesting a trade-off between the adaptations to each step. Step-specific adaptations could play a crucial role in the chronic phase of infections in any diseases that show similar small colony variants (also known as SCV) to X. nematophila.ImportanceWithin-host evolution has been described in many bacterial diseases, and the genetic basis behind the adaptations stimulated a lot of interest. Yet, the studied adaptations are generally focused on antibiotic resistance, rarely on the adaptation to the environment given by the host, and the potential trade-off hindering adaptations to each step of the infection are rarely considered. Those trade-offs are key to understand intra-host evolution, and thus the dynamics of the infection. However, the understanding of these trade-offs supposes a detailed study of host-pathogen interactions at each step of the infection process, with for each step an adapted methodology. Using Drosophila melanogaster as host and the bacteria Xenorhabdus nematophila, we investigated the bacterial adaptations resulting from GASP mutations known to induce small colony variant (SCV) phenotype positively selected within-the-host over the course of an infection, and the trade-off between step-specific adaptations.

Ending Malaria with Gene Drive Technologies? A Normative Analysis of the Role of Humans in Nature

2021 ◽  
Vol 66 (Special Issue) ◽  
pp. 60-60
Author(s):  
Nienke de Graeff ◽  
Karin Jongsma ◽  
Annelien Bredenoord
Keyword(s):  
Moral Status ◽  
Gene Drive ◽  
Moral Permissibility ◽  
Ethical Debate ◽  
Trade Offs ◽  
As Species ◽  
Intractable Problems ◽  
Vector Borne ◽  
The Relationship

"Gene drive technologies (GDT) promote the rapid, progressive spread of gene alterations within a population or a species of wild organisms. If GDT are successfully developed and implemented, they could help to resolve intractable problems in the realm of vector-borne disease, invasive species and pest control, but these technologies have also raised concerns regarding the moral permissibility of interfering in nature in this way. In particular, it has been argued that perspectives on humans’ relationship to nature and their impact on and manipulation of ecosystems play a crucial role in determining the moral permissibility of GDT. Nonetheless, these perspectives have thus far remained underexplored in the emerging ethical debate on GDT. In this presentation, I identify these perspectives and concerns and analyse them normatively. Four issues are demonstrated to be of central importance in deciding whether (a particular) use of GDT is in accordance with the relationship humans should have to nature: (1) the moral status of and direct duties towards different organisms; (2) the prioritisation of duties towards different organisms in case of conflicting claims; (3) the moral (ir)relevance of ‘wildness’; and (4) the moral status of holistic entities such as species and ecosystems. The normative positions that can be taken on these issues are presented and critically assessed to determine the moral permissibility of particular applications of GDT. Doing so elucidates the central trade-offs and points of contention in the ethical debate on interfering in nature in this way. "

scholarly journals Competition between strains of Borrelia afzelii inside the rodent host and the tick vector

2018 ◽  
Vol 285 (1890) ◽  
pp. 20181804 ◽  
Author(s):  
Dolores Genné ◽  
Anouk Sarr ◽  
Andrea Gomez-Chamorro ◽  
Jonas Durand ◽  
Claire Cayol ◽  
...  
Keyword(s):  
Competitive Ability ◽  
Vertebrate Host ◽  
Mixed Infections ◽  
Rodent Host ◽  
Borrelia Afzelii ◽  
Arthropod Vector ◽  
Tick Vector ◽  
Trade Offs ◽  
Tick Transmission ◽  
Vector Borne

Multiple-strain pathogens often establish mixed infections inside the host that result in competition between strains. In vector-borne pathogens, the competitive ability of strains must be measured in both the vertebrate host and the arthropod vector to understand the outcome of competition. Such studies could reveal the existence of trade-offs in competitive ability between different host types. We used the tick-borne bacterium Borrelia afzelii to test for competition between strains in the rodent host and the tick vector, and to test for a trade-off in competitive ability between these two host types. Mice were infected via tick bite with either one or two strains, and these mice were subsequently used to create ticks with single or mixed infections. Competition in the rodent host reduced strain-specific host-to-tick transmission and competition in the tick vector reduced the abundance of both strains. The strain that was competitively superior in host-to-tick transmission was competitively inferior with respect to bacterial abundance in the tick. This study suggests that in multiple-strain vector-borne pathogens there are trade-offs in competitive ability between the vertebrate host and the arthropod vector. Such trade-offs could play an important role in the coexistence of pathogen strains.

scholarly journals Does deforestation drive visceral leishmaniasis transmission? A causal analysis

2021 ◽  
Vol 288 (1957) ◽  
pp. 20211537
Author(s):  
Cleber Vinicius Brito dos Santos ◽  
Anaiá da Paixão Sevá ◽  
Guilherme Loureiro Werneck
Keyword(s):  
Visceral Leishmaniasis ◽  
Development Strategy ◽  
Environmental Changes ◽  
Causal Effects ◽  
Vector Borne Diseases ◽  
Trade Offs ◽  
Disease Occurrence ◽  
Key Factor ◽  
Vector Borne

Vector-borne diseases (VBDs) are important contributors to the global disease burden and are a key factor in perpetuating economic inequality. Although environmental changes are often cited as drivers of VBDs, the link between deforestation and VBD occurrence remains unclear. Here, we examined this relationship in detail using the spread of visceral leishmaniasis (VL) in São Paulo state (Brazil) as the case study. We used a two-step approach to estimate the causal effects (overall, direct, and indirect) of deforestation on the occurrence of the VL vector, canine visceral leishmaniasis (CVL), and human visceral leishmaniasis (HVL). We first estimated the parameters via a double Metropolis–Hastings algorithm and then estimated the causal effects through a Gibbs sampler. We observed that the odds of vector, CVL, and HVL occurrence were 2.63-, 2.07-, and 3.18-fold higher, respectively, in deforested compared with forested municipalities. We also identified a significant influence of the presence of vector, CVL, and HVL in one municipality on disease occurrence in previously naive neighbouring municipalities. Lastly, we found that a hypothetical reduction in deforestation prevalence from 50 to 0% across the state would reduce vector, CVL, and HVL occurrence by 11%, 6.67%, and 29.87%, respectively. Our results suggest that implementing an eco-friendly development strategy that considers trade-offs between agriculture, urbanization, and conservation could be an effective mechanism of controlling VL.

A novel pilin subunit from Xenorhabdus nematophila, an insect pathogen, confers pest resistance in tobacco and tomato

2015 ◽  
Vol 34 (11) ◽  
pp. 1863-1872 ◽  
Author(s):  
Punam Kumari ◽  
Gagan Kumar Mahapatro ◽  
Nirupama Banerjee ◽  
Neera Bhalla Sarin
Keyword(s):  
Pest Resistance ◽  
Xenorhabdus Nematophila ◽  
Insect Pathogen ◽  
Pilin Subunit

scholarly journals Insecticidal Pilin Subunit from the Insect Pathogen Xenorhabdus nematophila

2004 ◽  
Vol 186 (19) ◽  
pp. 6465-6476 ◽  
Author(s):  
Puneet Khandelwal ◽  
Devapriya Choudhury ◽  
Ajanta Birah ◽  
M. K. Reddy ◽  
Gorakh Prasad Gupta ◽  
...  
Keyword(s):  
Recombinant Protein ◽  
Protein Complex ◽  
Point Mutations ◽  
Xenorhabdus Nematophila ◽  
Insect Pathogen ◽  
Larval Host ◽  
Pilin Subunit ◽  
Sugar Derivatives ◽  
Pilin Protein

ABSTRACT Xenorhabdus nematophila is an insect pathogen and produces protein toxins which kill the larval host. Previously, we characterized an orally toxic, large, outer membrane-associated protein complex from the culture medium of X. nematophila. Here, we describe the cloning, expression, and characterization of a 17-kDa pilin subunit of X. nematophila isolated from that protein complex. The gene was amplified by PCR, cloned, and expressed in Escherichia coli. The recombinant protein was refolded in vitro in the absence of its cognate chaperone by using a urea gradient. The protein oligomerized during in vitro refolding, forming multimers. Point mutations in the conserved N-terminal residues of the pilin protein greatly destabilized its oligomeric organization, demonstrating the importance of the N terminus in refolding and oligomerization of the pilin subunit by donor strand complementation. The recombinant protein was cytotoxic to cultured Helicoverpa armigera larval hemocytes, causing agglutination and subsequent release of the cytoplasmic enzyme lactate dehydrogenase. The agglutination of larval cells by the 17-kDa protein was inhibited by several sugar derivatives. The biological activity of the purified recombinant protein indicated that it has a conformation similar to that of the native protein. The 17-kDa pilin subunit was found to be orally toxic to fourth- or fifth-instar larvae of an important crop pest, H. armigera, causing extensive damage to the midgut epithelial membrane. To our knowledge, this is first report describing an insecticidal pilin subunit of a bacterium.

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