scholarly journals Cell-length heterogeneity: a population-level solution to growth/virulence trade-offs in the plant pathogen Dickeya dadantii

2019 ◽  
Vol 15 (8) ◽  
pp. e1007703 ◽  
Author(s):  
Zhouqi Cui ◽  
Ching-Hong Yang ◽  
Roshni R. Kharadi ◽  
Xiaochen Yuan ◽  
George W. Sundin ◽  
...  
Keyword(s):  
Plant Pathogen ◽  
Population Level ◽  
Cell Length ◽  
Dickeya Dadantii ◽  
Trade Offs

scholarly journals Cell-length heterogeneity: a population-level solution to growth/virulence trade-offs in the plant pathogen Dickeya dadantii

2019 ◽  
Author(s):  
Zhouqi Cui ◽  
Ching-Hong Yang ◽  
Roshni R. Kharadi ◽  
Xiaochen Yuan ◽  
George W. Sundin ◽  
...  
Keyword(s):  
Plant Pathogens ◽  
Plant Cell Wall ◽  
Early Stage ◽  
Secondary Infection ◽  
Large Population ◽  
Infected Plant ◽  
Cell Length ◽  
Necrotrophic Pathogen ◽  
Dickeya Dadantii ◽  
Trade Offs

Necrotrophic plant pathogens acquire nutrients from dead plant cells, which requires the disintegration of the plant cell wall and tissue structures by the pathogen. Infected plants lose tissue integrity and functional immunity as a result, exposing the nutrient rich, decayed tissues to the environment. One challenge for the necrotrophs to successfully cause secondary infection (infection spread from an initially infected plant to the nearby uninfected plants) is to effectively utilize nutrients released from hosts towards building up a large population before other saprophytes come. In this study, we observed that the necrotrophic pathogen Dickeya dadantii exhibited heterogeneity in bacterial cell length in an isogenic population during infection of potato tuber. While some cells were regular rod-shape (<10μm), the rest elongated into filamentous cells (>10μm). Short cells tended to occur at the interface of healthy and diseased tissues, during the early stage of infection when active attacking and killing is occurring, while filamentous cells tended to form when large amount of nutrients were released at a later stage of infection. Short cells expressed all necessary virulence factors and motility, whereas filamentous cells did not engage in virulence, were non-mobile and more sensitive to environmental stress. However, compared to the short cells, the filamentous cells displayed elevated metabolism and faster growth, which may benefit the pathogens to build up a large population necessary for the secondary infection. The segregation of the two subpopulations was dependent on differential expression of the alarmone guanosine tetraphosphate (ppGpp). When exposed to fresh tuber tissues or freestanding water, filamentous cells quickly transformed to short virulent cells. The pathogen adaptation of cell length heterogeneity identified in this study presents a model for how some necrotrophs balance virulence and vegetative growth to maximize fitness during infection.

scholarly journals The case for Option B and Optional B+: Ensuring that South Africa’s commitment to eliminating mother-to-child transmission of HIV becomes a reality

2012 ◽  
Vol 13 (4) ◽  
pp. 178 ◽  
Author(s):  
D Besada ◽  
G Van Cutsem ◽  
E Goemaere ◽  
N Ford ◽  
H Bygrave ◽  
...  
Keyword(s):  
South African ◽  
Population Level ◽  
World Health ◽  
Mother To Child Transmission ◽  
Child Transmission ◽  
Trade Offs ◽  
The Individual ◽  
Mother To Child ◽  
African Journal ◽  
In Pregnancy

In a previous issue of the Southern African Journal of HIV Medicine, Pillay and Black summarised the trade-offs of the safety of efavirenz use in pregnancy (Pillay P, Black V. Safety, strength and simplicity of efavirenz in pregnancy. Southern African Journal of HIV Medicine 2012;13(1):28-33.). Highlighting the benefits of the World Health Organization’s proposed options for the prevention of mother-to-child transmission (PMTCT) of HIV, the authors argued that the South African government should adopt Option B as national PMTCT policy and pilot projects implementing Option B+ as a means of assessing the individual- and population-level effect of the intervention. We echo this call and further propose that the option to remain on lifelong antiretroviral therapy, effectively adopting PMTCT Option B+, be offered to pregnant women following the cessation of breastfeeding, for their own health, following the provision of counselling on associated benefits and risks. Here we highlight the benefits of Options B and B+.

scholarly journals The nucleoid-associated proteins H-NS and FIS modulate the DNA supercoiling response of the pel genes, the major virulence factors in the plant pathogen bacterium Dickeya dadantii

2012 ◽  
Vol 40 (10) ◽  
pp. 4306-4319 ◽  
Author(s):  
Zghidi-Abouzid Ouafa ◽  
Sylvie Reverchon ◽  
Thomas Lautier ◽  
Georgi Muskhelishvili ◽  
William Nasser
Keyword(s):  
Virulence Factors ◽  
Plant Pathogen ◽  
Dna Supercoiling ◽  
Dickeya Dadantii ◽  
Associated Proteins

Black bear (Ursus americanus) functional resource selection relative to intraspecific competition and human risk

2017 ◽  
Vol 95 (3) ◽  
pp. 203-212 ◽  
Author(s):  
Jared F. Duquette ◽  
Jerrold L. Belant ◽  
Clay M. Wilton ◽  
Nicholas Fowler ◽  
Brittany W. Waller ◽  
...  
Keyword(s):  
Intraspecific Competition ◽  
Resource Selection ◽  
Ursus Americanus ◽  
Spatial Scales ◽  
Population Level ◽  
Reproductive Age ◽  
Functional Responses ◽  
Vegetation Productivity ◽  
Riparian Corridors ◽  
Trade Offs

The spatial scales at which animals make behavioral trade-offs is assumed to relate to the scales at which factors most limiting resources and increasing mortality risk occur. We used global positioning system collar locations of 29 reproductive-age female black bears (Ursus americanus Pallas, 1780) in three states to assess resource selection relative to bear population-specific density, an index of vegetation productivity, riparian corridors, or two road classes of and within home ranges during spring–summer of 2009–2013. Female resource selection was best explained by functional responses to vegetation productivity across nearly all populations and spatial scales, which appeared to be influenced by variation in bear density (i.e., intraspecific competition). Behavioral trade-offs were greatest at the landscape scale, but except for vegetation productivity, were consistent for populations across spatial scales. Females across populations selected locations nearer to tertiary roads, but females in Michigan and Mississippi selected main roads and avoided riparian corridors, whereas females in Missouri did the opposite, suggesting population-level trade-offs between resource (e.g., food) acquisition and mortality risks (e.g., vehicle collisions). Our study emphasizes that female bear population-level resource selection can be influenced by multiple spatially dependent factors, and that scale-dependent functional behavior should be identified for management of bears across their range.

scholarly journals PARASITE-HOST FITNESS TRADE-OFFS CHANGE WITH PARASITE IDENTITY: GENOTYPE-SPECIFIC INTERACTIONS IN A PLANT-PATHOGEN SYSTEM

Evolution ◽  
2005 ◽  
Vol 59 (12) ◽  
pp. 2518-2524 ◽  
Author(s):  
Lucie Salvaudon ◽  
Virginie Héraudet ◽  
Jacqui A. Shykoff
Keyword(s):  
Plant Pathogen ◽  
Specific Interactions ◽  
Host Fitness ◽  
Trade Offs

scholarly journals Fitness trade-offs of group formation and movement by Thomson's gazelles in the Serengeti ecosystem

2018 ◽  
Vol 373 (1746) ◽  
pp. 20170013 ◽  
Author(s):  
John M. Fryxell ◽  
Andrew M. Berdahl
Keyword(s):  
Group Formation ◽  
Movement Ecology ◽  
Population Level ◽  
Collective Behaviour ◽  
Illustrative Case ◽  
Environmental Fluctuation ◽  
Serengeti Ecosystem ◽  
Individual Fitness ◽  
Trade Offs ◽  
Risk Of Predation

Collective behaviours contributing to patterns of group formation and coordinated movement are common across many ecosystems and taxa. Their ubiquity is presumably due to altering interactions between individuals and their predators, resources and physical environment in ways that enhance individual fitness. On the other hand, fitness costs are also often associated with group formation. Modifications to these interactions have the potential to dramatically impact population-level processes, such as trophic interactions or patterns of space use in relation to abiotic environmental variation. In a wide variety of empirical systems and models, collective behaviour has been shown to enhance access to ephemeral patches of resources, reduce the risk of predation and reduce vulnerability to environmental fluctuation. Evolution of collective behaviour should accordingly depend on the advantages of collective behaviour weighed against the costs experienced at the individual level. As an illustrative case study, we consider the potential trade-offs on Malthusian fitness associated with patterns of group formation and movement by migratory Thomson's gazelles in the Serengeti ecosystem. This article is part of the theme issue ‘Collective movement ecology’.

scholarly journals Aggressive or moderate drug therapy for infectious diseases? Trade-offs between different treatment goals at the individual and population levels

2018 ◽  
Author(s):  
Jérémie Scire ◽  
Nathanaël Hozé ◽  
Hildegard Uecker
Keyword(s):  
Drug Therapy ◽  
Antimicrobial Resistance ◽  
Disease Burden ◽  
Treatment Success ◽  
Population Level ◽  
Drug Dose ◽  
Efficient Treatment ◽  
Trade Offs ◽  
The Individual ◽  
Emergence Of Resistance

AbstractAntimicrobial resistance is one of the major public health threats of the 21st century. There is a pressing need to adopt more efficient treatment strategies in order to prevent the emergence and spread of resistant strains. The common approach is to treat patients with high drug doses, both to clear the infection quickly and to reduce the risk of de novo resistance. Recently, several studies have argued that, at least in some cases, low-dose treatments could be more suitable to reduce the within-host emergence of antimicrobial resistance. However, the choice of a drug dose may have consequences at the population level, which has received little attention so far.Here, we study the influence of the drug dose on resistance and disease management at the host and population levels. We develop a nested two-strain model and unravel trade-offs in treatment benefits between an individual and the community. We use several measures to evaluate the benefits of any dose choice. Two measures focus on the emergence of resistance, at the host level and at the population level. The other two focus on the overall treatment success: the outbreak probability and the disease burden. We find that different measures can suggest different dosing strategies. In particular, we identify situations where low doses minimize the risk of emergence of resistance at the individual level, while high or intermediate doses prove most beneficial to improve the treatment efficiency or even to reduce the risk of resistance in the population.Author summaryThe obvious goals of antimicrobial drug therapy are rapid patient recovery and low disease prevalence in the population. However, achieving these goals is complicated by the rapid evolution and spread of antimicrobial resistance. A sustainable treatment strategy needs to account for the risk of resistance and keep it in check. One parameter of treatment is the drug dosage, which can vary within certain limits. It has been proposed that lower doses may, in some cases, be more suitable than higher doses to reduce the risk of resistance evolution in any one patient. However, if lower doses prolong the period of infectiousness, such a strategy has consequences for the pathogen dynamics of both strains at the population level. Here, we set up a nested model of within-host and between-host dynamics for an acute self-limiting infection. We explore the consequences of drug dosing on several measures of treatment success: the risk of resistance at the individual and population levels and the outbreak probability and the disease burden of an epidemic. Our analysis shows that trade-offs may exist between optimal treatments under these various criteria. The criterion given most weight in the decision process ultimately depends on the disease and population under consideration.

scholarly journals Functional evaluation of out-of-the-box text-mining tools for data-mining tasks

2014 ◽  
Vol 22 (1) ◽  
pp. 121-131 ◽  
Author(s):  
Kenneth Jung ◽  
Paea LePendu ◽  
Srinivasan Iyer ◽  
Anna Bauer-Mehren ◽  
Bethany Percha ◽  
...  
Keyword(s):  
Language Processing ◽  
Text Processing ◽  
Population Level ◽  
Large Datasets ◽  
Functional Evaluation ◽  
Trade Off ◽  
Trade Offs ◽  
Linguistic Understanding ◽  
Significant Difference ◽  
Very Large Datasets

Abstract Objective The trade-off between the speed and simplicity of dictionary-based term recognition and the richer linguistic information provided by more advanced natural language processing (NLP) is an area of active discussion in clinical informatics. In this paper, we quantify this trade-off among text processing systems that make different trade-offs between speed and linguistic understanding. We tested both types of systems in three clinical research tasks: phase IV safety profiling of a drug, learning adverse drug–drug interactions, and learning used-to-treat relationships between drugs and indications. Materials We first benchmarked the accuracy of the NCBO Annotator and REVEAL in a manually annotated, publically available dataset from the 2008 i2b2 Obesity Challenge. We then applied the NCBO Annotator and REVEAL to 9 million clinical notes from the Stanford Translational Research Integrated Database Environment (STRIDE) and used the resulting data for three research tasks. Results There is no significant difference between using the NCBO Annotator and REVEAL in the results of the three research tasks when using large datasets. In one subtask, REVEAL achieved higher sensitivity with smaller datasets. Conclusions For a variety of tasks, employing simple term recognition methods instead of advanced NLP methods results in little or no impact on accuracy when using large datasets. Simpler dictionary-based methods have the advantage of scaling well to very large datasets. Promoting the use of simple, dictionary-based methods for population level analyses can advance adoption of NLP in practice.

Regulation of pel genes, major virulence factors in the plant pathogen bacterium Dickeya dadantii , is mediated by cooperative binding of the nucleoid-associated protein H-NS

2016 ◽  
Vol 167 (4) ◽  
pp. 247-253 ◽  
Author(s):  
Ouafa Zghidi-Abouzid ◽  
Elodie Hérault ◽  
Sylvie Rimsky ◽  
Sylvie Reverchon ◽  
William Nasser ◽  
...  
Keyword(s):  
Virulence Factors ◽  
Plant Pathogen ◽  
Cooperative Binding ◽  
Dickeya Dadantii
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