Genomic and environmental factors influence Wolbachia-Drosophila symbiosis

Intracellular, vertically transmitted bacteria form complex and intimate relationships with their hosts. Wolbachia, maternally transmitted α- proteobacteria, live within the cells of numerous arthropod species. Wolbachia are famous master manipulators of insect reproduction: to favour their own spread they can induce male killing, parthenogenesis or cytoplasmic incompatibility. Wolbachia can also protect various insects from pathogens, which makes them a promising tool for the control of vector-borne diseases. Mosquitoes with Wolbachia have already been released in the wild to eliminate dengue. Yet, how Wolbachia manipulate their hosts remains largely unknown.(...)Fundação para a Ciência e a Tecnologi

Mutualism Breakdown by Amplification of Wolbachia Genes

Most insect species are associated with vertically transmitted endosymbionts. Because of the mode of transmission, the fitness of these symbionts is dependent on the fitness of the hosts. Therefore, these endosymbionts need to control their proliferation in order to minimize their cost for the host. The genetic bases and mechanisms of this regulation remain largely undetermined. The maternally inherited bacteria of the genus Wolbachia are the most common endosymbionts of insects, providing some of them with fitness benefits. In Drosophila melanogaster, Wolbachia wMelPop is a unique virulent variant that proliferates massively in the hosts and shortens their lifespan. The genetic bases of wMelPop virulence are unknown, and their identification would allow a better understanding of how Wolbachia levels are regulated. Here we show that amplification of a region containing eight Wolbachia genes, called Octomom, is responsible for wMelPop virulence. Using Drosophila lines selected for carrying Wolbachia with different Octomom copy numbers, we demonstrate that the number of Octomom copies determines Wolbachia titers and the strength of the lethal phenotype. Octomom amplification is unstable, and reversion of copy number to one reverts all the phenotypes. Our results provide a link between genotype and phenotype in Wolbachia and identify a genomic region regulating Wolbachia proliferation. We also prove that these bacteria can evolve rapidly. Rapid evolution by changes in gene copy number may be common in endosymbionts with a high number of mobile elements and other repeated regions. Understanding wMelPop pathogenicity and variability also allows researchers to better control and predict the outcome of releasing mosquitoes transinfected with this variant to block human vector-borne diseases. Our results show that transition from a mutualist to a pathogen may occur because of a single genomic change in the endosymbiont. This implies that there must be constant selection on endosymbionts to control their densities.FCT PhD fellowship: (SFRH/BD/51625/2011)

Comment on Rohrscheib et al. 2016 "Intensity of mutualism breakdown is determined by temperature not amplification of Wolbachia genes"

This deposit is composed by the main article plus the supplementary materials of the publication.Rohrscheib et al. (PLOS Pathogens, 2016) discuss the interaction between the pathogenicity of the wMel variant wMelPop, temperature and Octomom copy number. The effect of temperature on wMelPop pathogenicity was already reported in the original work on wMelPop. The absence of pathogenicity at low temperatures was also shown before. We have recently demonstrated, in Chrostek and Teixeira 2015, that Octomom copy number determines wMelPop pathogenicity.Fundação para a Ciência e Tecnologia grants: (PTDC/BEX­GMG/3128/2014); EMBO Long Term Fellowship: (EMBO ALTF 1497-2015); Marie Curie Actions; European Commission grants: (LTFCOFUND2013, GA-2013-609409).info:eu-repo/semantics/publishedVersio

Comparison of hyaluronic acid in patients with rheumatoid arthritis, systemic sclerosis and systemic lupus erythematosus

The aim of the present study was to determine and compare the concentration of hyaluronic acid (HA) in rheumatoid arthritis (RA), systemic sclerosis (SSc) and systemic lupus erythematosus (SLE), and its correlation with parameters of disease activity and duration. The hypothesis was that HA should be increased in rheumatic diseases. We also expected that HA could be a marker of disease activity and inflammation in some of these diseases. The study group comprised 149 patients with RA, SSc and SLE hospitalized in the Department of Rheumatology and Internal Diseases, Medical University of Bialystok (Bialystok, Poland) and 30 healthy controls. The concentrations of HA, C-reactive protein (CRP) and rheumatoid factor (RF) were measured using Architect ci8200; haemoglobin, platelets on Sysmex XS-800i; and erythrocyte sedimentation rate (ESR) on Sediplus S 2000 analysers. Statistical analysis was performed using Statistica 13.3 PL. Hyaluronic acid was increased in RA, SLE and SSc when compared to controls (P < 0.001, P = 0.011, and P = 0.015, respectively). There were no differences in HA between rheumatic diseases (P = 0.840). Hyaluronic acid positively correlated with SLE activity (P = 0.025). In RA, HA positively correlated with ESR (P = 0.028) and CRP (P = 0.009). However, HA was not found to correlate with the duration of rheumatic diseases. Hyaluronic acid concentration undergoes changes in rheumatic diseases with no difference between RA, SLE and SSc. In RA, HA concentration can be a marker of inflammation, while in SLE patients an indicator of disease activity

Independence of carbohydrate-deficient isoforms of transferrin and cyclic citrullinated peptides in rheumatoid arthritis

AbstractObjectiveThe aim of this study was to assess the relationship between the two types of posttranslational modifications of proteins in RA: glycosylation on the example of carbohydrate-deficient transferrin and citrullination by means of autoantibodies to cyclic citrullinated peptides.MethodsThe study was carried out in 50 RA patients. CDT was measured using N Latex CDT immunonephelometric test, the results were presented in absolute and relative units. Anti-CCP were measured using the chemiluminescent method and rheumatoid factor by immunoturbidimetric method.Results80% of RA patients were positive for anti-CCP, 70% for RF and 62% for both, anti-CCP and RF. The level of %CDT was significantly elevated, but absolute CDT level was not changed. The mean absolute CDT concentration was higher in anti-CCP positive patients than that in anti-CCP negative. CDT (absolute and relative concentration) did not correlate with anti-CCP and RF. However, serum RF significantly correlated with anti-CCP. %CDT did not correlate with anti-CCP, but absolute level correlated with anti-CCP only in anti-CCP negative and RF negative patients. CDT did not correlate with RF, but solely with anti-CCP in anti-CCP negative patients. Anti-CCP correlated with DAS 28 only in anti-CCP negative RA, but CDT (absolute and relative units) correlated with DAS 28 in all patients and in anti-CCP positive RA.ConclusionsThese results suggest that the changes in CDT and anti-CCP concentrations are not associated with oneself and indicate on the independence of these posttranslational modifications in rheumatoid arthritis. Only the alterations in transferrin glycosylation reflected the activity of RA

Wolbachia-Conferred Antiviral Protection Is Determined by Developmental Temperature

Insects are often infected with beneficial intracellular bacteria. The bacterium Wolbachi

Wolbachia Variants Induce Differential Protection to Viruses in Drosophila melanogaster: A Phenotypic and Phylogenomic Analysis

Wolbachia are intracellular bacterial symbionts that are able to protect various insect hosts from viral infections. This tripartite interaction was initially described in Drosophila melanogaster carrying wMel, its natural Wolbachia strain. wMel has been shown to be genetically polymorphic and there has been a recent change in variant frequencies in natural populations. We have compared the antiviral protection conferred by different wMel variants, their titres and influence on host longevity, in a genetically identical D. melanogaster host. The phenotypes cluster the variants into two groups--wMelCS-like and wMel-like. wMelCS-like variants give stronger protection against Drosophila C virus and Flock House virus, reach higher titres and often shorten the host lifespan. We have sequenced and assembled the genomes of these Wolbachia, and shown that the two phenotypic groups are two monophyletic groups. We have also analysed a virulent and over-replicating variant, wMelPop, which protects D. melanogaster even better than the closely related wMelCS. We have found that a ~21 kb region of the genome, encoding eight genes, is amplified seven times in wMelPop and may be the cause of its phenotypes. Our results indicate that the more protective wMelCS-like variants, which sometimes have a cost, were replaced by the less protective but more benign wMel-like variants. This has resulted in a recent reduction in virus resistance in D. melanogaster in natural populations worldwide. Our work helps to understand the natural variation in wMel and its evolutionary dynamics, and inform the use of Wolbachia in arthropod-borne disease control.FCT PhD fellowship: (SFRH/BD/51625/2011), Royal Society University Research Fellowship

Is Anopheles gambiae a natural host of Wolbachia?

Abstract Wolbachia ( Alphaproteobacteria, Rickettsiales ) is an intraovarially-transmitted symbiont of insects able to exert striking phenotypes, including reproductive manipulations and pathogen blocking. These phenotypes make Wolbachia a promising tool to combat mosquito-borne diseases. Although Wolbachia is present in the majority of terrestrial arthropods, including many disease vectors, it was considered absent from Anopheles gambiae mosquitos, the main vectors of malaria in sub-Saharan Africa. In 2014, Wolbachia sequences were detected in A. gambiae samples collected in Burkina Faso. Subsequently, similar evidence came from collections all over Africa, revealing a high Wolbachia 16S sequence diversity, low abundance, and a lack of congruence between host and symbiont phylogenies. Here, we reanalyze and discuss recent evidence on the presence of Wolbachia sequences in A. gambiae. We find that although detected at increasing frequencies, the unusual properties of these Wolbachia sequences render them insufficient to diagnose natural infections in A. gambiae . Future studies should focus on uncovering the origin of Wolbachia sequence variants in Anopheles and seeking sequence-independent evidence for this new symbiosis. Understanding the ecology of Anopheles mosquitos and their interactions with Wolbachia will be key in designing successful, integrative approaches to limit malaria spread. Although the prospect of using Wolbachia to fight malaria is intriguing, the newly discovered strains do not bring it closer to realization. Significance Anopheles gambiae mosquitos are the main vectors of malaria, threatening around half of the world’s population. The bacterial symbiont Wolbachia can interfere with disease transmission by other important insect vectors, but until recently it was thought to be absent from natural A. gambiae populations. Here, we critically analyze the genomic, metagenomic, PCR, imaging and phenotypic data presented in support of the presence of natural Wolbachia infections in A. gambiae. We find that they are insufficient to diagnose Wolbachia infections and argue for the need of obtaining robust data confirming basic Wolbachia characteristics in this system. Determining Wolbachia infection status of Anopheles is critical due to its potential to influence Anopheles population structure and Plasmodium transmission