Maintenance of adaptive differentiation by Wolbachia induced bidirectional cytoplasmic incompatibility: the importance of sib-mating and genetic systems

<p>Abstract</p> <p>Background</p> <p>Bacteria of the genus <it>Wolbachia </it>are reproductive parasites widespread among arthropods. The most common effect arising from the presence of <it>Wolbachia </it>in a population is Cytoplasmic Incompatibility (CI), whereby postmating reproductive isolation occurs in crosses between an infected male and an uninfected female, or when a male is infected with a different strain of <it>Wolbachia </it>to that of the female (bidirectional CI). Previous theoretical models have demonstrated that bidirectional CI can contribute to the genetic divergence of populations in haploid and diploid organisms. However, haplodiploid organisms were not considered in these models even though they include <it>Nasonia </it>parasitoid wasps – the best example of the implication of <it>Wolbachia </it>in ongoing speciation. Moreover, previous work did not investigate inbreeding mating systems, which are frequently observed in arthropod species.</p> <p>Results</p> <p>We developed a stochastic two-island model which simulated three genetic scenarios, diploidy, haploidy, and haplodiploidy, with two CI phenotypes being considered for the latter: (1) male development of female progeny; and (2) mortality of fertilized eggs. We also investigated the effect of varying the proportion of sib mating. In the model each allopatric population was initially fixed for a single allele at a nuclear locus under positive selection and infected with one strain of <it>Wolbachia</it>. Each simulation presupposed that the two populations were fixed for a different allele and a different strain of <it>Wolbachia</it>. The degree of genetic differentiation observed in the locus under selection due to bidirectional CI was much lower for the two haplodiploid phenotypes than for either diploids or haploids. Furthermore, we demonstrated that sib-mating may compensate for the lower efficiency of bidirectional CI in haplodiploids by maintaining genetic divergence.</p> <p>Conclusion</p> <p>Our model suggests that maintenance of genetic differentiation facilitated by <it>Wolbachia </it>is more likely to occur in diploids and haploids than in haplodiploids. However, increasing the level of sib-mating may compensate for the weak effect of bidirectional CI in haplodiploids. Our work therefore gives a potential explanation for why the haplodiploid <it>Nasonia </it>species, which are infected with bidirectionally incompatible <it>Wolbachia </it>strains and undergo sib-mating, have differentiated genetically and maintained this differentiation without premating isolation.</p

Distribution, pest status and agro-dimatic preferences of lepidopteran stem borers of maize in Kenya

Lepidopterous stem borers are the main field insect pests that attack maize, Zea mays L. in tropical Africa. A survey was carried during the long and short rain cropping seasons of 2002/2003 across six main agro-climatic zones (ACZs) to determine the spatial distribution of important stem borer species in Kenya. A total of 474 visits were made in the seventy-eight localities conveniently chosen to represent each of the six ACZs. 189,600 stems were checked for infestation, of which 27,799 infested stems were destructively cut and dissected for stem borer larvae identification. An average of 1.4 stem borer larvae were recovered per infested plant. 54.5% of the recovered larvae were identified as Chilo partellus (Swinhoe) (Crambidae), 39.7% as Busseola fusca (Fuller) (Noctuidae), 4.5% as Sesamia calamistis Hampson (Noctuidae) and 0.8% as Chilo orichalcociliellus (Strand) (Crambidae). Minor species present included Eldana saccharina Walker (Pyralidae), Sesamia nonagrioides (Lefebvre) (Noctuidae), Sesamia cretica Lederer (Noctuidae), Sesamia sp. (Noctuidae), Sciomesa piscator Fletcher (Noctuidae), Busseola sp near phaia (Noctuidae), Chilo sp, Ematheudes sp 1 (Pyralidae) and Ematheudes sp 2 (Pyralidae). Farms were grouped into respective ACZs for statistical analysis and subsequent comparison of dominant species: Results indicated that B. fusca was the dominant stem borer species in high potential zones (highland tropics, moist transitional zone and moist mid-altitude) while the exotic C. partellus dominated smallholder farms in low potential zones (dry mid-altitude, dry transional and lowland tropical zone). Within each ACZs, there was evidence of variation in species proportions between seasons. These spatio-temporal differences in community structure are discussed in terms of agro-climatic biological adaptations

Viral cystatin evolution and three-dimensional structure modelling: A case of directional selection acting on a viral protein involved in a host-parasitoid interaction

<p>Abstract</p> <p>Background</p> <p>In pathogens, certain genes encoding proteins that directly interact with host defences coevolve with their host and are subject to positive selection. In the lepidopteran host-wasp parasitoid system, one of the most original strategies developed by the wasps to defeat host defences is the injection of a symbiotic polydnavirus at the same time as the wasp eggs. The virus is essential for wasp parasitism success since viral gene expression alters the immune system and development of the host. As a wasp mutualist symbiont, the virus is expected to exhibit a reduction in genome complexity and evolve under wasp phyletic constraints. However, as a lepidopteran host pathogenic symbiont, the virus is likely undergoing strong selective pressures for the acquisition of new functions by gene acquisition or duplication. To understand the constraints imposed by this particular system on virus evolution, we studied a polydnavirus gene family encoding cyteine protease inhibitors of the cystatin superfamily.</p> <p>Results</p> <p>We show that <it>cystatins </it>are the first bracovirus genes proven to be subject to strong positive selection within a host-parasitoid system. A generated three-dimensional model of <it>Cotesia congregata </it>bracovirus cystatin 1 provides a powerful framework to position positively selected residues and reveal that they are concentrated in the vicinity of actives sites which interact with cysteine proteases directly. In addition, phylogenetic analyses reveal two different <it>cystatin </it>forms which evolved under different selective constraints and are characterized by independent adaptive duplication events.</p> <p>Conclusion</p> <p>Positive selection acts to maintain <it>cystatin </it>gene duplications and induces directional divergence presumably to ensure the presence of efficient and adapted cystatin forms. Directional selection has acted on key cystatin active sites, suggesting that cystatins coevolve with their host target. We can strongly suggest that cystatins constitute major virulence factors, as was already proposed in previous functional studies.</p

Гранитоиды обрамления Криворожской структуры. Проблемы корреляции геологических тел и комплексов

Current population genetic models fail to cope with genetic differentiation for species with large, contiguous and heterogeneous distribution. We show that in such a case, genetic differentiation can be predicted at equilibrium by circuit theory, where conductance corresponds to abundance in species distribution models (SDM). Circuit-SDM approach was used for the phylogeographic study of the lepidopteran cereal stemborer Busseola fusca Füller (Noctuidae) across sub-Saharan Africa. Species abundance was surveyed across its distribution range. SDM models were optimized and selected by cross validation. Relationship between observed matrices of genetic differentiation between individuals, and matrices of resistance distance was assessed through Mantel tests and redundancy discriminant analyses (RDA). A total of 628 individuals from 130 localities in 17 countries were genotyped at 7 microsatellite loci. Six population clusters were found based on a Bayesian analysis. The eastern margin of Dahomey Gap between East and West Africa was the main factor of genetic differentiation. The SDM projections at present, last interglacial and last glacial maximum periods were used for estimation of circuit resistance between locations of genotyped individuals. For all periods of time, when using either all individuals or only East-African individuals, partial Mantel r and RDA analyses conditioning on geographic distance were found significant. Under future projections (year 2080), partial r and RDA significance were different. From this study, it is concluded that analytical solutions provided by circuit theory are useful for the evolutionary management of populations and for phylogeographic analysis when coalescence times are not accessible by approximate Bayesian simulations

Parasitism of Lepidopterous Stem Borers in Cultivated and Natural Habitats

Plant infestation, stem borer density, parasitism, and parasitoid abundance were assessed during two years in two host plants, Zea mays (L.) (Cyperales: Poaceae) and Sorghum bicolor (L.) (Cyperales: Poaceae), in cultivated habitats. The four major host plants (Cyperus spp., Panicum spp., Pennisetum spp., and Sorghum spp.) found in natural habitats were also assessed, and both the cultivated and natural habitat species occurred in four agroecological zones in Kenya. Across habitats, plant infestation (23.2%), stem borer density (2.2 per plant), and larval parasitism (15.0%) were highest in maize in cultivated habitats. Pupal parasitism was not higher than 4.7% in both habitats, and did not vary with locality during each season or with host plant between each season. Cotesia sesamiae (Cameron) and C. flavipes Cameron (Hymenoptera: Braconidae) were the key parasitoids in cultivated habitats (both species accounted for 76.4% of parasitized stem borers in cereal crops), but not in natural habitats (the two Cotesia species accounted for 14.5% of parasitized stem borers in wild host plants). No single parasitoid species exerted high parasitism rates on stem borer populations in wild host plants. Low stem borer densities across seasons in natural habitats indicate that cereal stem borer pests do not necessarily survive the non-cropping season feeding actively in wild host plants. Although natural habitats provided refuges for some parasitoid species, stem borer parasitism was generally low in wild host plants. Overall, because parasitoids contribute little in reducing cereal stem borer pest populations in cultivated habitats, there is need to further enhance their effectiveness in the field to regulate these pests

Digital transformation of health and care to sustain Planetary Health: The MASK proof-of-concept for airway diseases-POLLAR symposium under the auspices of Finland's Presidency of the EU, 2019 and MACVIA-France, Global Alliance against Chronic Respiratory Diseases (GARD, WH0) demonstration project, Reference Site Collaborative Network of the European Innovation Partnership on Active and Healthy Ageing

In December 2019, a conference entitled "Europe That Protects: Safeguarding Our Planet, Safeguarding Our Health" was held in Helsinki. It was co-organized by the Finnish Institute for Health and Welfare, the Finnish Environment Institute and the European Commission, under the auspices of Finland's Presidency of the EU. As a side event, a symposium organized as the final POLLAR (Impact of air POLLution on Asthma and Rhinitis) meeting explored the digital transformation of health and care to sustain planetary health in airway diseases. The Finnish Allergy Programme collaborates with MASK (Mobile Airways Sentinel NetworK) and can be considered as a proof-of-concept to impact Planetary Health. The Good Practice of DG Sante (The Directorate-General for Health and Food Safety) on digitally-enabled, patient-centred care pathways is in line with the objectives of the Finnish Allergy Programme. The ARIACARE-Digital network has been deployed in 25 countries. It represents an example of the digital cross-border exchange of real-world data and experience with the aim to improve patient care. The integration of information technology tools for climate, weather, air pollution and aerobiology in mobile Health applications will enable the development of an alert system. Citizens will thus be informed about personal environmental threats, which may also be linked to indicators of Planetary Health and sustainability. The digital transformation of the public health policy was also proposed, following the experience of the Agency for Health Quality and Assessment of Catalonia (AQuAS)

ARIA digital anamorphosis: Digital transformation of health and care in airway diseases from research to practice

Digital anamorphosis is used to define a distorted image of health and care that may be viewed correctly using digital tools and strategies. MASK digital anamorphosis represents the process used by MASK to develop the digital transformation of health and care in rhinitis. It strengthens the ARIA change management strategy in the prevention and management of airway disease. The MASK strategy is based on validated digital tools. Using the MASK digital tool and the CARAT online enhanced clinical framework, solutions for practical steps of digital enhancement of care are proposed

Extracting the maximum historical information on pine wood nematode worldwide invasion from genetic data

A recommendation – based on reviews by Aude Gilabert and one anonymous reviewer – of the article: Mallez, S., Castagnone, C., Lombaert, E., Castagnone-Sereno, P. and Guillemaud, T. (2021) Inference of the worldwide invasion routes of the pinewood nematode Bursaphelenchus xylophilus using approximate Bayesian computation analysis. bioRxiv, 452326, ver. 6 peer-reviewed and recommended by Peer community in Zoology. doi: https://doi.org/10.1101/45232

Valorisation du groupement sulfoximine en synthèse asymétrique (application à la réaction d'ortho-métallation, synthèse de nouveaux modèles du NADH)

Dans une première partie, nous avons développé une voie de synthèse conduisant à la S-phényl-S-tert-butylsulfoximine énantiopure. Différentes S-phényl-S-tert-butylsulfoximine N-substituées ont été préparées et ortho-métallées. Nous avons ainsi montré la capacité du groupe sulfoximine à diriger la réaction d'ortho-métallation et mis au point les conditions de métallation. Ceci nous a permis d'accéder à de nouvelles sulfoximines ortho-substituées. L'utilisation d'électrophiles prochiraux a permis l'obtention des produits ortho-substitués correspondants avec des excès diastéréoisomériques variant de modestes à très bons. Nous avons mis en évidence dans certains cas une réaction secondaire de déterbutylation conduisant au dérivé sulfinamide correspondant. Cette réaction a été étudiée et des conditions de déterbutylation optimisées ont été mises au point. Enfin, il a été montré que cette réaction de déterbutylation est stéréospécifique et qu'elle a lieu avec rétention de configuration. Dans une seconde partie, nous avons développé de nouveaux modèles du NADH en série quinoléine possédant des dérivés soufrés comme inducteur chiral. Une première voie de synthèse a été envisagée à partir de la réaction de condensation de Friedländer. Cette voie n'a pas aboutie en raison de l'effet électroattracteur des groupes soufrés et de l'encombrement stérique en position C2 de la quinoléine. En conséquence, une approche via une réaction de quaternarisation intramoléculaire a été développée, mais celle-ci n'a pu aboutir. Une seconde approche concernant la synthèse de quinoléines moins encombrées à partir de 3-bromoquinoléines a été mise au point. Plusieurs modèles ont été synthétisés en série quinoléine et 6,7-diméthoxyquinoléine comportant un groupement sulfoximine, sulfoxyde ou sulfilimine comme inducteur de chiralité. Parmi ces modèles, seules ceux comportant un sulfoxyde ont permis la réduction du benzoyle formiate de méthyle en mandélate de méthyle. Enfin, cette réduction a eu lieu avec un excellent excès énantiomérique.The first project deals with the use of the sulfoximine as an ortho-directing group in metalation reactions. After optimization of the metalation conditions, the sulfoximine group proved to be an excellent ortho-directing group. Several electrophiles were tested to afford the corresponding ortho-fonctionalized aryl sulfoximines in good yields. The use of prochiral electrophiles allowed us to obtain modest to good diasteroselectivities up to 95%. During this study we observed a side reaction due to a S-deterbutylation. This deterbutylation provided new sulfinamides with high stereoselectivities. After optimization of the S-deterbutylation reaction, the corresponding enantiopures sulfinamides were obtained in good yields. The second project deals with the synthesis of new chiral NADH models in sulphur series. The sulphur allows to install the chirality close to the active site of the NADH model. We chose to develop models in quinoline series. The first relies on a Friedlander type reaction. This strategy allows to introduce the chirality with the commercially available enantiopure S-phenyl-S-methylsulfoximine. All attempts to quaternize the quinoline nitrogen failed probably due to a steric hindrance and the withdrawing effect of the sulfoximine group. To circumvent this problem, we turned our attention to a less hindered structure. This strategy is based on C-S stereospecific bond formation. The key reaction is a halogen metal exchange on the 3-bromoquinoline. Various 1,4-dihydroquinolines substituted at C-3 by a chiral sulfoxide, sulfoximine and racemic sulfilimine derivatives were prepared in few steps. The mimics bearing the sulfoxide auxiliary showed to be highly enantioselective affording the methyl mandelate in 98% e.e.ROUEN-BU Sciences (764512102) / SudocSudocFranceF