scholarly journals Forward genetics in Wolbachia: Regulation of Wolbachia proliferation by the amplification and deletion of an addictive genomic island

PLoS Genetics ◽  
2021 ◽  
Vol 17 (6) ◽  
pp. e1009612
Author(s):  
Elves H. Duarte ◽  
Ana Carvalho ◽  
Sergio López-Madrigal ◽  
João Costa ◽  
Luís Teixeira
Keyword(s):  
Experimental Approach ◽  
Genomic Island ◽  
Genomic Region ◽  
Forward Genetics ◽  
Viral Pathogens ◽  
Arthropod Species ◽  
Bacterial Endosymbionts ◽  
Time Of Infection ◽  
Fitness Benefits

Wolbachia is one of the smost prevalent bacterial endosymbionts, infecting approximately 40% of terrestrial arthropod species. Wolbachia is often a reproductive parasite but can also provide fitness benefits to its host, as, for example, protection against viral pathogens. This protective effect is currently being applied to fight arboviruses transmission by releasing Wolbachia-transinfected mosquitoes. Titre regulation is a crucial aspect of Wolbachia biology. Higher titres can lead to stronger phenotypes and fidelity of transmission but can have a higher cost to the host. Since Wolbachia is maternally transmitted, its fitness depends on host fitness, and, therefore, its cost to the host may be under selection. Understanding how Wolbachia titres are regulated and other aspects of Wolbachia biology has been hampered by the lack of genetic tools. Here we developed a forward genetic screen to identify new Wolbachia over-proliferative mutant variants. We characterized in detail two new mutants, wMelPop2 and wMelOctoless, and show that the amplification or loss of the Octomom genomic region lead to over-proliferation. These results confirm previous data and expand on the complex role of this genomic region in the control of Wolbachia proliferation. Both new mutants shorten the host lifespan and increase antiviral protection. Moreover, we show that Wolbachia proliferation rate in Drosophila melanogaster depends on the interaction between Octomom copy number, the host developmental stage, and temperature. Our analysis also suggests that the life shortening and antiviral protection phenotypes of Wolbachia are dependent on different, but related, properties of the endosymbiont; the rate of proliferation and the titres near the time of infection, respectively. We also demonstrate the feasibility of a novel and unbiased experimental approach to study Wolbachia biology, which could be further adapted to characterize other genetically intractable bacterial endosymbionts.

scholarly journals Regulation of Wolbachia proliferation by the amplification and deletion of an addictive genomic island

2020 ◽  
Author(s):  
Elves H Duarte ◽  
Ana Carvalho ◽  
Sergio López-Madrigal ◽  
Luís Teixeira
Keyword(s):  
Experimental Approach ◽  
Genomic Island ◽  
Genomic Region ◽  
Viral Pathogens ◽  
Forward Genetic Screen ◽  
Arthropod Species ◽  
Bacterial Endosymbionts ◽  
Time Of Infection ◽  
Fitness Benefits

AbstractWolbachia is one of the most prevalent bacterial endosymbionts, infecting approximately 40% of terrestrial arthropod species. Wolbachia is often a reproductive parasite but can also provide fitness benefits to its host, as for example protection against viral pathogens. This protective effect is currently being applied to fight arboviruses transmission by releasing Wolbachia-transinfected mosquitoes. Titre regulation is a crucial aspect of Wolbachia biology. Higher titres can lead to stronger phenotypes and fidelity of transmission but can have a cost to the host. Since Wolbachia is maternally transmitted, its fitness depends on host fitness, and, therefore, its cost to the host needs to be controlled. Understanding this and other aspects of Wolbachia biology has been hampered by the lack of genetic tools. Here we developed a new forward genetic screen to identify Wolbachia over-proliferative mutant variants. We characterized in detail two of these new mutants, wMelPop2 and wMelOctoless, and show that the amplification or loss of the Octomom genomic region causes their over-proliferation. These results confirm previous data and expand on the complex role of this genomic region in the control of Wolbachia proliferation. Both new mutants shorten the host lifespan and increase antiviral protection. Moreover, we show that Wolbachia proliferation rate in Drosophila melanogaster depends on the interaction between Octomom copy number, the host developmental stage, and temperature. Our analysis also suggests that the life shortening phenotype and antiviral protection of Wolbachia are dependent on related, but different, properties of the endosymbiont; the rate of proliferation and the titres at time of infection, respectively. Altogether, we demonstrate the feasibility of a novel and unbiased experimental approach to study Wolbachia biology, which can be further adapted to characterize other genetically intractable bacterial endosymbionts.

An experimental approach to communal coping

2021 ◽  
pp. 026540752199246
Author(s):  
Melissa Zajdel ◽  
Vicki S. Helgeson
Keyword(s):  
Health Outcomes ◽  
Positive Relationship ◽  
Experimental Approach ◽  
Positive Mood ◽  
Self Report ◽  
Communal Coping ◽  
Observational Measures ◽  
Relationship Outcomes ◽  
The Individual

Communal coping has been linked to better psychological and physical health across a variety of stressful contexts. However, there has been no experimental work causally linking communal coping to relationship and health outcomes. In addition, research has emphasized the collaboration over the shared appraisal component of communal coping. The present study sought to isolate the role of appraisal by manipulating whether dyads viewed a stressor as shared or individual. Friend dyads (n = 64 dyads; 128 participants) were randomly assigned to view a stressor as either a shared or an individual problem, but both groups were allowed to work together. Across self-report and observational measures dyads reported more collaboration and support, better relationship outcomes, and more positive mood after the stressor in the shared than the individual appraisal group. This is the first laboratory evidence to establish causal links of communal coping—specifically shared appraisal—to positive relationship and health outcomes.

scholarly journals First Report of Hepatitis E Virus in Shellfish in Southeast Italy

2020 ◽  
Vol 11 (1) ◽  
pp. 43
Author(s):  
Gianfranco La Bella ◽  
Maria Grazia Basanisi ◽  
Gaia Nobili ◽  
Valentina Terio ◽  
Elisabetta Suffredini ◽  
...  
Keyword(s):  
Real Time ◽  
Hepatitis E Virus ◽  
Potential Role ◽  
Hepatitis E ◽  
Developed Countries ◽  
Rt Pcr ◽  
Viral Pathogens ◽  
Apulia Region ◽  
Causative Agents

Hepatitis E virus (HEV) represents one of the principal causative agents of hepatitis globally. Among the five HEV genotypes affecting humans, genotypes 3 and 4 are zoonotic and are the main source of hepatitis E in developed countries. HEV has been detected in several foods. The present work investigated the presence of this virus in shellfish sold at retail in the Apulia region of Italy. The presence of HEV RNA was assessed by real-time RT-PCR in 225 shellfish samples collected during 2018. Overall, two (0.89%) of these samples tested positive for HEV RNA. To our knowledge, this is the first notification of the detection of HEV in mussels sold at retail in the Apulia region. These data highlight the potential role of shellfish as a vehicle for the transmission of viral pathogens.

scholarly journals Arthropod community structure in pastures of an island archipelago (Azores): looking for local–regional species richness patterns at fine-scales

2004 ◽  
Vol 94 (2) ◽  
pp. 111-121 ◽  
Author(s):  
P.A.V. Borges ◽  
V.K. Brown
Keyword(s):  
Species Richness ◽  
Regional Scale ◽  
Local Scale ◽  
Local Species Richness ◽  
Β Diversity ◽  
Arthropod Species ◽  
Α Diversity ◽  
Local Species ◽  
Richness Patterns

AbstractThe arthropod species richness of pastures in three Azorean islands was used to examine the relationship between local and regional species richness over two years. Two groups of arthropods, spiders and sucking insects, representing two functionally different but common groups of pasture invertebrates were investigated. The local–regional species richness relationship was assessed over relatively fine scales: quadrats (= local scale) and within pastures (= regional scale). Mean plot species richness was used as a measure of local species richness (= α diversity) and regional species richness was estimated at the pasture level (= γ diversity) with the ‘first-order-Jackknife’ estimator. Three related issues were addressed: (i) the role of estimated regional species richness and variables operating at the local scale (vegetation structure and diversity) in determining local species richness; (ii) quantification of the relative contributions of α and β diversity to regional diversity using additive partitioning; and (iii) the occurrence of consistent patterns in different years by analysing independently between-year data. Species assemblages of spiders were saturated at the local scale (similar local species richness and increasing β-diversity in richer regions) and were more dependent on vegetational structure than regional species richness. Sucking insect herbivores, by contrast, exhibited a linear relationship between local and regional species richness, consistent with the proportional sampling model. The patterns were consistent between years. These results imply that for spiders local processes are important, with assemblages in a particular patch being constrained by habitat structure. In contrast, for sucking insects, local processes may be insignificant in structuring communities.

scholarly journals The Role of the Immune System from an Evolutionary Perspective

2019 ◽  
pp. 198-209
Author(s):  
Carsten Schradin ◽  
Rainer H. Straub
Keyword(s):  
Evolutionary Medicine ◽  
Future Generations ◽  
Lifetime Reproductive Success ◽  
Life History Stage ◽  
Evolutionary Perspective ◽  
Lifetime Fitness ◽  
Fitness Consequences ◽  
Reproductive Life ◽  
Fitness Benefits

“Nothing in Biology makes sense, except in the light of evolution.” This famous citation of Theodosius Dobzhansky also underlies the integrative field of evolutionary medicine, which faces the challenge to combine (patho-)physiological mechanisms with evolutionary function. Here we introduce a concept from the study of animal behavior, which are the four questions of Tinbergen that consider: 1. the ontogeny of an individual describing its development, 2. its physiological machinery, which 3. has fitness consequences influencing 4. the evolutionary history (phylogeny) of future generations. It is shown how this concept can be applied to infectious disease and to chronic inflammatory systemic diseases. Evolutionary medicine takes lifetime reproductive success into account. The hypothesis to be tested is that mechanisms underlying a disease in old age might have higher fitness benefits in the pre-reproductive and/or reproductive life history stage, leading to an overall increased lifetime fitness.

STUDIES ON THE ARTHROPOD FAUNA OF ALFALFA: II. ARTHROPOD–FUNGUS ASSOCIATIONS

1972 ◽  
Vol 104 (9) ◽  
pp. 1405-1412
Author(s):  
A. G. Wheeler
Keyword(s):  
Seasonal Changes ◽  
Immature Stages ◽  
Arthropod Species ◽  
Late Fall ◽  
Medicago Saliva ◽  
Arthropod Fauna

AbstractObservations were made during 1967 to 1969 at Ithaca, N.Y., supplemented by collections at New Cumberland and Carlisle, Pa., on arthropods associated with fungi occurring on alfalfa, Medicago saliva L. Five species of Coleoptera, two species of Diptera, one species each of Collembola and Psocoptera, and nine species of Acari were reared or collected consistently from fungus-covered alfalfa leaves, stems, and seed pods. Attraction to fungi on the plants, principally Alternaria sp., accounted for the presence on alfalfa of arthropod species that normally might be considered as accidentals or visitors. The mycetophagous species thus contributed to the richness of the alfalfa fauna. Immature stages of several species were collected only in late fall or on 3- or 4-year-old plants. The possible role of the fungus-feeding species in seasonal changes in the alfalfa fauna and changes in the fauna in successive years is discussed.

Wingless signaling in the Drosophila embryo: zygotic requirements and the role of the frizzled genes

Development ◽  
1999 ◽  
Vol 126 (3) ◽  
pp. 577-586 ◽  
Author(s):  
H. Muller ◽  
R. Samanta ◽  
E. Wieschaus
Keyword(s):  
Genomic Region ◽  
Drosophila Embryo ◽  
Surface Molecules ◽  
New Genes ◽  
Wingless Signaling ◽  
Frizzled Receptors ◽  
Signaling Receptors ◽  
Genomic Regions ◽  
High Degree

Wingless signaling plays a central role during epidermal patterning in Drosophila. We have analyzed zygotic requirements for Wingless signaling in the embryonic ectoderm by generating synthetic deficiencies that uncover more than 99% of the genome. We found no genes required for initial wingless expression, other than previously identified segmentation genes. In contrast, maintenance of wingless expression shows a high degree of zygotic transcriptional requirements. Besides known genes, we have identified at least two additional genomic regions containing new genes involved in Wingless maintenance. We also assayed for the zygotic requirements for Wingless response and found that no single genomic region was required for the cytoplasmic accumulation of Armadillo in the receiving cells. Surprisingly, embryos homozygously deleted for the candidate Wingless receptor, Dfrizzled2, showed a normal Wingless response. However, the Armadillo response to Wingless was strongly reduced in double mutants of both known members of the frizzled family in Drosophila, frizzled and Dfrizzled2. Based on their expression pattern during embryogenesis, different Frizzled receptors may play unique but overlapping roles in development. In particular, we suggest that Frizzled and Dfrizzled2 are both required for Wingless autoregulation, but might be dispensable for late Engrailed maintenance. While Wingless signaling in embryos mutant for frizzled and Dfrizzled2 is affected, Wingless protein is still internalized into cells adjacent to wingless-expressing cells. Incorporation of Wingless protein may therefore involve cell surface molecules in addition to the genetically defined signaling receptors of the frizzled family.

Role of the gut microbiota in airway immunity and host defense against respiratory infections

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Maike Willers ◽  
Dorothee Viemann
Keyword(s):  
Gut Microbiota ◽  
Host Defense ◽  
Gut Microbiome ◽  
Respiratory Infections ◽  
Current Knowledge ◽  
Viral Pathogens ◽  
Commensal Microbiota ◽  
Enhanced Resistance ◽  
The Impact

Abstract Colonization of the intestine with commensal bacteria is known to play a major role in the maintenance of human health. An altered gut microbiome is associated with various ensuing diseases including respiratory diseases. Here, we summarize current knowledge on the impact of the gut microbiota on airway immunity with a focus on consequences for the host defense against respiratory infections. Specific gut commensal microbiota compositions and functions are depicted that mediate protection against respiratory infections with bacterial and viral pathogens. Lastly, we highlight factors that have imprinting effects on the establishment of the gut microbiota early in life and are potentially relevant in the context of respiratory infections. Deepening our understanding of these relationships will allow to exploit the knowledge on how gut microbiome maturation needs to be modulated to ensure lifelong enhanced resistance towards respiratory infections.

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