Traits of a mussel transmissible cancer are reminiscent of a parasitic life style

AbstractSome cancers have evolved the ability to spread from host to host by transmission of cancerous cells. These rare biological entities can be considered parasites with a host-related genome. Still, we know little about their specific adaptation to a parasitic lifestyle. MtrBTN2 is one of the few lineages of transmissible cancers known in the animal kingdom. Reported worldwide, MtrBTN2 infects marine mussels. We isolated MtrBTN2 cells circulating in the hemolymph of cancerous mussels and investigated their phenotypic traits. We found that MtrBTN2 cells had remarkable survival capacities in seawater, much higher than normal hemocytes. With almost 100% cell survival over three days, they increase significantly their chances to infect neighboring hosts. MtrBTN2 also triggered an aggressive cancerous process: proliferation in mussels was ~ 17 times higher than normal hemocytes (mean doubling time of ~ 3 days), thereby favoring a rapid increase of intra-host population size. MtrBTN2 appears to induce host castration, thereby favoring resources re-allocation to the parasites and increasing the host carrying capacity. Altogether, our results highlight a series of traits of MtrBTN2 consistent with a marine parasitic lifestyle that may have contributed to the success of its persistence and dissemination in different mussel populations across the globe.

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Simulating the next steps in badger control for bovine tuberculosis in England

PLoS ONE ◽

10.1371/journal.pone.0248426 ◽

2021 ◽

Vol 16 (3) ◽

pp. e0248426

Author(s):

Graham C. Smith ◽

Richard Budgey

Keyword(s):

Simulation Model ◽

Carrying Capacity ◽

Bovine Tuberculosis ◽

Management Strategies ◽

Fertility Control ◽

Host Population ◽

Dramatic Reduction ◽

Control Option ◽

Badger Vaccination ◽

The Uk

Industry-led culling of badgers has occurred in England to reduce the incidence of bovine tuberculosis in cattle for a number of years. Badger vaccination is also possible, and a move away from culling was “highly desirable” in a recent report to the UK government. Here we used an established simulation model to examine badger control option in a post-cull environment in England. These options included no control, various intermittent culling, badger vaccination and use of a vaccine combined with fertility control. The initial simulated cull led to a dramatic reduction in the number of infected badgers present, which increased slowly if there was no further badger management. All three approaches led to a further reduction in the number of infected badgers, with little to choose between the strategies. We do note that of the management strategies only vaccination on its own leads to a recovery of the badger population, but also an increase in the number of badgers that need to be vaccinated. We conclude that vaccination post-cull, appears to be particularly effective, compared to vaccination when the host population is at carrying capacity.

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Evolutionary epidemiology theory of vaccination

Pertussis ◽

10.1093/oso/9780198811879.003.0008 ◽

2018 ◽

pp. 133-143 ◽

Cited By ~ 1

Author(s):

Sylvain Gandon

Keyword(s):

Theoretical Framework ◽

Host Population ◽

Phenotypic Traits ◽

High Coverage ◽

Evolutionary Epidemiology ◽

Short And Long Term ◽

Evolutionary Consequences ◽

Parasite Populations ◽

Specific Parasite

The aim of vaccination is to prevent or limit the risk of pathogen infections for individual hosts but large vaccination coverage often has dramatic epidemiological consequences at the scale of the whole host population. This massive perturbation of the ecology and transmission of the pathogen can also have important evolutionary effects. In particular, vaccine-driven evolution may lead to the spread of new pathogen variants that may erode the benefits of vaccination. This chapter presents a theoretical framework for modelling the short- and long-term epidemiological and evolutionary consequences of vaccination. This framework can be used to make quantitative predictions about the speed of such evolutionary processes. This work helps identify the relevant phenotypic traits that need to be measured in specific parasite populations in order to evaluate the potential evolutionary consequences of vaccination. In particular, this may help in the debate regarding the involvement of evolution in the re-emergence of pertussis in spite of the high coverage of vaccination.

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Putative plasmid prophages of Bacillus cereus sensu lato may hold the key to undiscovered phage diversity

Scientific Reports ◽

10.1038/s41598-021-87111-3 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Emma G. Piligrimova ◽

Olesya A. Kazantseva ◽

Andrey N. Kazantsev ◽

Nikita A. Nikulin ◽

Anna V. Skorynina ◽

...

Keyword(s):

Bacillus Cereus ◽

Bacterial Species ◽

Experimental Studies ◽

Host Population ◽

Whole Genome ◽

Actual Number ◽

Host Cytoplasm ◽

Bacterial Viruses ◽

Biological Entities ◽

Bacillus Cereus Sensu Lato

AbstractBacteriophages are bacterial viruses and the most abundant biological entities on Earth. Temperate bacteriophages can form prophages stably maintained in the host population: they either integrate into the host genome or replicate as plasmids in the host cytoplasm. As shown, tailed temperate bacteriophages may form circular plasmid prophages in many bacterial species of the taxa Firmicutes, Gammaproteobacteria and Spirochaetes. The actual number of such prophages is thought to be underestimated for two main reasons: first, in bacterial whole genome-sequencing assemblies, they are difficult to distinguish from actual plasmids; second, there is an absence of experimental studies which are vital to confirm their existence. In Firmicutes, such prophages appear to be especially numerous. In the present study, we identified 23 genomes from species of the Bacillus cereus group that were deposited in GenBank as plasmids and may belong to plasmid prophages with little or no homology to known viruses. We consider these putative prophages worth experimental assays since it will broaden our knowledge of phage diversity and suggest that more attention be paid to such molecules in all bacterial sequencing projects as this will help in identifying previously unknown phages.

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COEVOLUTIONARY DYNAMICS OF PREDATOR-PREY INTERACTIONS

International Journal of Biomathematics ◽

10.1142/s1793524512600157 ◽

2012 ◽

Vol 05 (03) ◽

pp. 1260015

Author(s):

JIAN ZU ◽

JINLIANG WANG ◽

YASUHIRO TAKEUCHI

Keyword(s):

Frequency Dependence ◽

Carrying Capacity ◽

Adaptive Dynamics ◽

Evolutionary Model ◽

Phenotypic Traits ◽

Predator Population ◽

Evolutionary Branching ◽

Ecological Processes ◽

Predator Species ◽

Selection Processes

In this paper, with the method of adaptive dynamics, we investigate the coevolution of phenotypic traits of predator and prey species. The evolutionary model is constructed from a deterministic approximation of the underlying stochastic ecological processes. Firstly, we investigate the ecological and evolutionary conditions that allow for continuously stable strategy and evolutionary branching. We find that evolutionary branching in the prey phenotype will occur when the frequency dependence in the prey carrying capacity is not strong. Furthermore, it is found that if the two prey branches move far away enough, the evolutionary branching in the prey phenotype will induce the secondary branching in the predator phenotype. The final evolutionary outcome contains two prey and two predator species. Secondly, we show that under symmetric interactions the evolutionary model admits a supercritical Hopf bifurcation if the frequency dependence in the prey carrying capacity is very weak. Evolutionary cycle is a likely outcome of the mutation-selection processes. Finally, we find that frequency-dependent selection can drive the predator population to extinction under asymmetric interactions.

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Transmissible cancer in Tasmanian devils: localized lineage replacement and host population response

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2015.1468 ◽

2015 ◽

Vol 282 (1814) ◽

pp. 20151468 ◽

Cited By ~ 32

Author(s):

Rodrigo K. Hamede ◽

Anne-Maree Pearse ◽

Kate Swift ◽

Leon A. Barmuta ◽

Elizabeth P. Murchison ◽

...

Keyword(s):

Population Decline ◽

Emerging Infectious Diseases ◽

Infectious Agent ◽

Host Population ◽

Future Research ◽

Tasmanian Devil ◽

Genetic Management ◽

Genetic Lineages ◽

Devil Facial Tumour Disease ◽

Transmissible Cancer

Tasmanian devil facial tumour disease (DFTD) is a clonally transmissible cancer threatening the Tasmanian devil ( Sarcophilus harrisii ) with extinction. Live cancer cells are the infectious agent, transmitted to new hosts when individuals bite each other. Over the 18 years since DFTD was first observed, distinct genetic and karyotypic sublineages have evolved. In this longitudinal study, we investigate the associations between tumour karyotype, epidemic patterns and host demographic response to the disease. Reduced host population effects and low DFTD infection rates were associated with high prevalence of tetraploid tumours. Subsequent replacement by a diploid variant of DFTD coincided with a rapid increase in disease prevalence, population decline and reduced mean age of the population. Our results suggest a role for tumour genetics in DFTD transmission dynamics and epidemic outcome. Future research, for this and other highly pathogenic emerging infectious diseases, should focus on understanding the evolution of host and pathogen genotypes, their effects on susceptibility and tolerance to infection, and their implications for designing novel genetic management strategies. This study provides evidence for a rapid localized lineage replacement occurring within a transmissible cancer epidemic and highlights the possibility that distinct DFTD genetic lineages may harbour traits that influence pathogen fitness.

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A 2-DIMENSIONAL MODEL FOR MACROPARASITIC INFECTIONS IN A HOST WITH LOGISTIC GROWTH

Journal of Biological System ◽

10.1142/s0218339095000769 ◽

1995 ◽

Vol 03 (03) ◽

pp. 833-849 ◽

Cited By ~ 1

Author(s):

ANDREA PUGLIESE ◽

ROBERTO ROSÀ

Keyword(s):

Carrying Capacity ◽

Negative Binomial ◽

Host Population ◽

Specific Pattern ◽

Logistic Growth ◽

Contact Rate ◽

Dimensional Model ◽

Parasite Distribution ◽

Stable Equilibria ◽

Disease Free

We analysed a model for the interaction of a macroparasite and a host population growing logistically. The model is obtained by approximating the parasite distribution with a negative binomial with a fixed clumping parameter. By letting the contact rate k vary, we found a complex pattern of bifurcations, including subcritical bifurcations of the disease-free equilibrium, Hopf and homoclinic bifurcations. The specific pattern depends on the interaction of the various parameters; in particular, alternative stable equilibria may occur only when the carrying capacity KN is sufficiently large, while periodic solutions may occur for all values of KN, if k is large enough.

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The Social Perspective of Tourism in review of Sustainability and Carrying Capacity: A Synthesis of Observations and Convictions.

Atna Journal of Tourism Studies ◽

10.12727/ajts.14.4 ◽

2015 ◽

Vol 10 (2) ◽

pp. 45-58

Author(s):

K.L Ajay ◽

Deleep Devasia

Keyword(s):

Theoretical Approach ◽

Carrying Capacity ◽

Tourism Development ◽

Host Population ◽

Social Perspective ◽

Economic Expansion ◽

Social Carrying Capacity ◽

The Social

Tourism is an authoritative branch in the socio-economic expansion in present-day epochs, backing diverse ways and reinforces the inter-connected processes. The development of tourism prompts changes, directly or indirectly in the social atmosphere of a destination. Changes in the social and economic fabric of particular towns, regions and even countries can be attributed directly to the advent of tourism and tourists. In light of these aspects, the social carrying capacity approaches involve using attitudes and tolerance levels of the host population to set limits on tourism development. This paper is a theoretical approach that throws light to the sociological perception of tourism with respect to carrying capacity thereby integrating the contemplations and criticisms regarding this subject.

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On the cross-sectional shape of the cellulose crystallites in the tunicate Halocynthia papillosa

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100160388 ◽

1990 ◽

Vol 48 (3) ◽

pp. 566-567

Author(s):

J.-F. Revol ◽

Y. Van Daele ◽

F. Gaill

Keyword(s):

Contrast Imaging ◽

Animal Kingdom ◽

Bright Field ◽

Field Mode ◽

Cross Sectional ◽

Ultrathin Sections ◽

The Cross ◽

Sectional Shape ◽

Valonia Ventricosa ◽

C Nmr

The only form of cellulose which could unequivocally be ascribed to the animal kingdom is the tunicin that occurs in the tests of the tunicates. Recently, high-resolution solid-state l3C NMR revealed that tunicin belongs to the Iβ form of cellulose as opposed to the Iα form found in Valonia and bacterial celluloses. The high perfection of the tunicin crystallites led us to study its crosssectional shape and to compare it with the shape of those in Valonia ventricosa (V.v.), the goal being to relate the cross-section of cellulose crystallites with the two allomorphs Iα and Iβ.In the present work the source of tunicin was the test of the ascidian Halocvnthia papillosa (H.p.). Diffraction contrast imaging in the bright field mode was applied on ultrathin sections of the V.v. cell wall and H.p. test with cellulose crystallites perpendicular to the plane of the sections. The electron microscope, a Philips 400T, was operated at 120 kV in a low intensity beam condition.

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