scholarly journals Wolbachia Infection in Wild Mosquitoes (Diptera: Culicidae): Implications for Transmission Modes and Host-Endosymbiont Associations

2020 ◽  
Author(s):  
Huicong Ding ◽  
Huiqing Yeo ◽  
Nalini Puniamoorthy
Keyword(s):  
Vertical Transmission ◽  
Wolbachia Infection ◽  
Host Shift ◽  
Control Technique ◽  
Pcr Screening ◽  
Modes Of Transmission ◽  
Reproductive Tissues ◽  
Specific Pcr ◽  
Transmission Modes ◽  
Event Based

Abstract Background: Wolbachia is an intracellular bacterial endosymbiont found in most insect lineages. In mosquitoes, the endosymbiont’s influence on host reproduction and arboviral transmission has spurred numerous studies aimed at using Wolbachia-infection as a vector control technique. However, there exist several gaps in the literature regarding the natural Wolbachia infection across species, modes of transmission as well as the associations between various Wolbachia lineages and their hosts. This study aims to address these by exploring mosquito-Wolbachia associations and their evolutionary implications.Methods: We conducted tissue-specific PCR screening of Wolbachia infection in wild mosquitoes from Singapore using the wsp molecular marker. Tissues examined include leg, gut, and reproductive tissues. We also explored mosquito-Wolbachia associations using three methods – a tanglegram, distance-based, and event-based method, and inferred instances of vertical transmission and host shifts. Results: We screened 271 adult mosquitoes (41 species and 14 genera) for Wolbachia and found that 43.9% of all individuals harboured Wolbachia. Eight out of the 21 infected species were not previously reported. We detected Wolbachia infections predominantly in the reproductive tissues, a strong indication of vertical transmission. Despite this, Wolbachia infection rates vary widely within a mosquito host species. There was no clear signal of co-phylogeny between the mosquito hosts and the twelve putative Wolbachia strains observed in our study. Host shift events were also observed. Conclusions: Our results suggest that the mosquito-Wolbachia relationship is complex and that a combination of transmission modes and multiple evolutionary events likely explain the distribution of Wolbachia diversity observed across mosquito hosts. This has implications towards understanding Wolbachia’s diversity, ecology, and utility as a biocontrol method.

scholarly journals Wolbachia infection in wild mosquitoes (Diptera: Culicidae): implications for transmission modes and host-endosymbiont associations in Singapore

2020 ◽  
Author(s):  
Huicong Ding ◽  
Huiqing Yeo ◽  
Nalini Puniamoorthy
Keyword(s):  
Vertical Transmission ◽  
Surface Protein ◽  
Wolbachia Infection ◽  
Host Shift ◽  
Control Technique ◽  
Pcr Screening ◽  
Reproductive Tissues ◽  
Specific Pcr ◽  
Transmission Modes ◽  
Event Based

Abstract Background: Wolbachia is an intracellular bacterial endosymbiont found in most insect lineages. In mosquitoes, the endosymbiont’s influence on host reproduction and arboviral transmission has spurred numerous studies aimed at using Wolbachia-infection as a vector control technique. However, there are several knowledge gaps in the literature and little is known about natural Wolbachia infection across species, transmission modes as well as the associations between various Wolbachia lineages and their hosts. This study aims to address these by exploring mosquito-Wolbachia associations and their evolutionary implications.Methods: We conducted tissue-specific PCR screening for Wolbachia infection in the leg, gut and reproductive tissues of wild mosquitoes from Singapore using the Wolbachia surface protein (wsp) molecular marker. Mosquito-Wolbachia associations were explored using three methods – a tanglegram, distance-based, and event-based method, and inferred instances of vertical transmission and host shifts.Results: Adult mosquitoes (271 specimens) representing 14 genera and 40 species were screened for Wolbachia. Overall, 21 species (51.2%) were found positive for Wolbachia, including Aedes (5 species) and Culex (5 species). Seven out of the 21 infected species were not previously reported: Aedes nr. fumidus, Aedes annandaelei, Uranotaenia obscura, Uranotaenia trilineata, Verrallina butleri, Verrallina sp., and Zeugnomyia gracilis. Wolbachia was predominantly detected in the reproductive tissues, an indication of vertical transmission. Despite this, Wolbachia infection rates vary widely within a mosquito host species. There is no clear signal of co-phylogeny between the mosquito hosts and the twelve putative Wolbachia strains observed in this study. Host shift events were also observed.Conclusions: Our results suggest that the mosquito-Wolbachia relationship is complex and that a combination of transmission modes and multiple evolutionary events likely explain the distribution of Wolbachia diversity observed across mosquito hosts. This has implications towards understanding Wolbachia’s diversity, ecology, and utility as a biocontrol method.

scholarly journals Wolbachia infection in wild mosquitoes (Diptera: Culicidae): implications for transmission modes and host-endosymbiont associations in Singapore

2020 ◽  
Author(s):  
Huicong Ding ◽  
Huiqing Yeo ◽  
Nalini Puniamoorthy
Keyword(s):  
Vertical Transmission ◽  
Surface Protein ◽  
Wolbachia Infection ◽  
Host Shift ◽  
Control Technique ◽  
Pcr Screening ◽  
Reproductive Tissues ◽  
Specific Pcr ◽  
Transmission Modes ◽  
Event Based

Abstract Background: Wolbachia is an intracellular bacterial endosymbiont found in most insect lineages. In mosquitoes, the endosymbiont’s influence on host reproduction and arboviral transmission has spurred numerous studies aimed at using Wolbachia-infection as a vector control technique. However, there are several knowledge gaps in the literature and little is known about natural Wolbachia infection across species, transmission modes as well as the associations between various Wolbachia lineages and their hosts. This study aims to address them by exploring mosquito-Wolbachia associations and their evolutionary implications.Methods: We conducted tissue-specific PCR screening for Wolbachia infection in the leg, gut and reproductive tissues of wild mosquitoes from Singapore using the Wolbachia surface protein (wsp) molecular marker. Mosquito-Wolbachia associations were explored using three methods – a tanglegram, distance-based, and event-based method, and inferred instances of vertical transmission and host shifts. Results: Adult mosquitoes (271 specimens) representing 14 genera and 40 species were screened for Wolbachia. Overall, 21 species (51.2%) were found positive for Wolbachia, including Aedes (5 species) and Culex (5 species). Seven out of the 21 infected species were not previously reported: Aedes nr. fumidus, Aedes annandaelei, Uranotaenia obscura, Uranotaenia trilineata, Verrallina butleri, Verrallina sp., and Zeugnomyia gracilis. Wolbachia was predominantly detected in the reproductive tissues, an indication of vertical transmission. Despite this, Wolbachia infection rates vary widely within a mosquito host species. There is no clear signal of co-phylogeny between the mosquito hosts and the twelve putative Wolbachia strains observed in this study. Host shift events were also observed. Conclusions: Our results suggest that the mosquito-Wolbachia relationship is complex and that combinations of transmission modes and multiple evolutionary events likely explain the distribution of Wolbachia diversity observed across mosquito hosts. This has implications towards understanding Wolbachia’s diversity, ecology, and utility as a biocontrol method.

scholarly journals Wolbachia infection in wild mosquitoes (Diptera: Culicidae): implications for transmission modes and host-endosymbiont associations in Singapore

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Huicong Ding ◽  
Huiqing Yeo ◽  
Nalini Puniamoorthy
Keyword(s):  
Vertical Transmission ◽  
Surface Protein ◽  
Wolbachia Infection ◽  
Host Shift ◽  
Control Technique ◽  
Host Shifts ◽  
Reproductive Tissues ◽  
Transmission Modes ◽  
Bacterial Endosymbionts ◽  
Event Based

Abstract Background Wolbachia are intracellular bacterial endosymbionts found in most insect lineages. In mosquitoes, the influence of these endosymbionts on host reproduction and arboviral transmission has spurred numerous studies aimed at using Wolbachia infection as a vector control technique. However, there are several knowledge gaps in the literature and little is known about natural Wolbachia infection across species, their transmission modes, or associations between various Wolbachia lineages and their hosts. This study aims to address these gaps by exploring mosquito-Wolbachia associations and their evolutionary implications. Methods We conducted tissue-specific polymerase chain reaction screening for Wolbachia infection in the leg, gut and reproductive tissues of wild mosquitoes from Singapore using the Wolbachia surface protein gene (wsp) molecular marker. Mosquito-Wolbachia associations were explored using three methods—tanglegram, distance-based, and event-based methods—and by inferred instances of vertical transmission and host shifts. Results Adult mosquitoes (271 specimens) representing 14 genera and 40 species were screened for Wolbachia. Overall, 21 species (51.2%) were found positive for Wolbachia, including five in the genus Aedes and five in the genus Culex. To our knowledge, Wolbachia infections have not been previously reported in seven of these 21 species: Aedes nr. fumidus, Aedes annandalei, Uranotaenia obscura, Uranotaenia trilineata, Verrallina butleri, Verrallina sp. and Zeugnomyia gracilis. Wolbachia were predominantly detected in the reproductive tissues, which is an indication of vertical transmission. However, Wolbachia infection rates varied widely within a mosquito host species. There was no clear signal of cophylogeny between the mosquito hosts and the 12 putative Wolbachia strains observed in this study. Host shift events were also observed. Conclusions Our results suggest that the mosquito-Wolbachia relationship is complex and that combinations of transmission modes and multiple evolutionary events likely explain the observed distribution of Wolbachia diversity across mosquito hosts. These findings have implications for a better understanding of the diversity and ecology of Wolbachia and for their utility as biocontrol agents.

Wolbachia and Cytoplasmic Incompatibility in the CaliforniaCulex pipiensMosquito Species Complex: Parameter Estimates and Infection Dynamics in Natural Populations

Genetics ◽  
2003 ◽  
Vol 165 (4) ◽  
pp. 2029-2038 ◽  
Author(s):  
Jason L Rasgon ◽  
Thomas W Scott
Keyword(s):  
Species Complex ◽  
Cytoplasmic Incompatibility ◽  
Natural Populations ◽  
Wolbachia Infection ◽  
Field Conditions ◽  
Parameter Estimates ◽  
Infection Prevalence ◽  
Infection Frequency ◽  
Specific Pcr ◽  
Vector Borne

AbstractBefore maternally inherited bacterial symbionts like Wolbachia, which cause cytoplasmic incompatibility (CI; reduced hatch rate) when infected males mate with uninfected females, can be used in a program to control vector-borne diseases it is essential to understand their dynamics of infection in natural arthropod vector populations. Our study had four goals: (1) quantify the number of Wolbachia strains circulating in the California Culex pipiens species complex, (2) investigate Wolbachia infection frequencies and distribution in natural California populations, (3) estimate the parameters that govern Wolbachia spread among Cx. pipiens under laboratory and field conditions, and (4) use these values to estimate equilibrium levels and compare predicted infection prevalence levels to those observed in nature. Strain-specific PCR, wsp gene sequencing, and crossing experiments indicated that a single Wolbachia strain infects Californian Cx. pipiens. Infection frequency was near or at fixation in all populations sampled for 2 years along a >1000-km north-south transect. The combined statewide infection frequency was 99.4%. Incompatible crosses were 100% sterile under laboratory and field conditions. Sterility decreased negligibly with male age in the laboratory. Infection had no significant effect on female fecundity under laboratory or field conditions. Vertical transmission was >99% in the laboratory and ∼98.6% in the field. Using field data, models predicted that Wolbachia will spread to fixation if infection exceeds an unstable equilibrium point above 1.4%. Our estimates accurately predicted infection frequencies in natural populations. If certain technical hurdles can be overcome, our data indicate that Wolbachia can invade vector populations as part of an applied transgenic strategy for vector-borne disease reduction.

scholarly journals The virome of German bats: comparing virus discovery approaches

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Claudia Kohl ◽  
Annika Brinkmann ◽  
Aleksandar Radonić ◽  
Piotr Wojtek Dabrowski ◽  
Kristin Mühldorfer ◽  
...  
Keyword(s):  
Virus Detection ◽  
Detection Methods ◽  
Single Type ◽  
Metagenomic Sequencing ◽  
Virus Discovery ◽  
Highly Pathogenic ◽  
Pcr Screening ◽  
Specific Pcr ◽  
Pathogenic Viruses ◽  
Viral Sequences

AbstractBats are known to be reservoirs of several highly pathogenic viruses. Hence, the interest in bat virus discovery has been increasing rapidly over the last decade. So far, most studies have focused on a single type of virus detection method, either PCR, virus isolation or virome sequencing. Here we present a comprehensive approach in virus discovery, using all three discovery methods on samples from the same bats. By family-specific PCR screening we found sequences of paramyxoviruses, adenoviruses, herpesviruses and one coronavirus. By cell culture we isolated a novel bat adenovirus and bat orthoreovirus. Virome sequencing revealed viral sequences of ten different virus families and orders: three bat nairoviruses, three phenuiviruses, one orbivirus, one rotavirus, one orthoreovirus, one mononegavirus, five parvoviruses, seven picornaviruses, three retroviruses, one totivirus and two thymoviruses were discovered. Of all viruses identified by family-specific PCR in the original samples, none was found by metagenomic sequencing. Vice versa, none of the viruses found by the metagenomic virome approach was detected by family-specific PCRs targeting the same family. The discrepancy of detected viruses by different detection approaches suggests that a combined approach using different detection methods is necessary for virus discovery studies.

scholarly journals Rapid divergence in independent aspects of the compatibility phenotype in the Spiroplasma/Drosophila interaction

2021 ◽  
Author(s):  
Joanne S. Griffin ◽  
Michael Gerth ◽  
Gregory D. D. Hurst
Keyword(s):  
Vertical Transmission ◽  
Host Species ◽  
High Efficiency ◽  
Host Shift ◽  
Direct Selection ◽  
New Host ◽  
Host Shifts ◽  
Species Pairs ◽  
Novel Host ◽  
Rapid Divergence

AbstractHeritable symbionts represent important components of host biology, both as antagonistic reproductive parasites and as beneficial protective partners. An important component of heritable microbes’ biology is their ability to establish in new host species, a process equivalent to a host shift for an infectiously transmitted parasite or pathogen. For a host shift to occur, the symbiont must be compatible with the host: it must not cause excess pathology, must have good vertical transmission, and possess a drive phenotype that enables spread. Classically, compatibility has been considered a declining function of genetic distance between novel and ancestral host species. Here we investigate the evolutionary lability of compatibility to heritable microbes by comparing the capacity for a symbiont to establish in two novel host species equally related to the ancestral host. Compatibility of the protective Spiroplasma from D. hydei with D. simulans and D. melanogaster was tested. The Spiroplasma had contrasting compatibility in these two host species. The transinfection showed pathology and low vertical transmission in D. melanogaster but was asymptomatic and transmitted with high efficiency in D. simulans. These results were not affected by the presence/absence of Wolbachia in either of the two species. The pattern of protection was not congruent with that for pathology/transmission, with protection being weaker in the D. simulans, the host in which Spiroplasma was asymptomatic and transmitted well. Further work indicated pathological interactions occurred in D. sechellia and D. yakuba, indicating that D. simulans was unusual in being able to carry the symbiont without damage. The differing compatibility of the symbiont with these closely related host species emphasises first the rapidity with which host-symbiont compatibility evolves despite compatibility itself not being subject to direct selection, and second the independence of the different components of compatibility (pathology, transmission, protection). This requirement to fit three different independently evolving aspects of compatibility, if commonly observed, is likely to be a major feature limiting the rate of host shifts. Moving forward, the variation between sibling species pairs observed above provides an opportunity to identify the mechanisms behind variable compatibility between closely related host species, which will drive hypotheses as to the evolutionary drivers of compatibility variation.

scholarly journals Minimal transmission in an influenza A (H3N2) human challenge-transmission model within a controlled exposure environment

2019 ◽  
Author(s):  
Jonathan S. Nguyen-Van-Tam ◽  
Ben Killingley ◽  
Joanne Enstone ◽  
Michael Hewitt ◽  
Jovan Pantelic ◽  
...  
Keyword(s):  
Attack Rate ◽  
Influenza A ◽  
Transmission Model ◽  
Epidemiological Methods ◽  
Large Droplet ◽  
Transmitted Infection ◽  
Modes Of Transmission ◽  
Transmission Modes ◽  
Building Ventilation ◽  
Transmission Studies

AbstractUncertainty about the importance of influenza transmission by airborne droplet nuclei generates controversy for infection control. Human challenge-transmission studies have been supported as the most promising approach to fill this knowledge gap. Healthy, seronegative volunteer ‘Donors’ (n=52) were randomly selected for intranasal challenge with influenza A/Wisconsin/67/2005 (H3N2). ‘Recipients’ randomized to Intervention (IR, n=40) or Control (CR, n=35) groups were exposed to Donors for four days. IRs wore face shields and hand sanitized frequently to limit large droplet and contact transmission. One transmitted infection was confirmed by serology in a CR, yielding a secondary attack rate of 2.9% among CR, 0% in IR (p=0.47 for group difference), and 1.3% overall, significantly less than 16% (p<0.001) expected based on a proof-of-concept study secondary attack rate and considering that there were twice as many Donors and days of exposure. The main difference between these studies was mechanical building ventilation in the follow-on study, suggesting a possible role for aerosols.Author summaryUnderstanding the relative importance of influenza modes of transmission informs strategic use of preventive measures to reduce influenza risk in high-risk settings such as hospitals and is important for pandemic preparedness. Given the increasing evidence from epidemiological modelling, exhaled viral aerosol, and aerobiological survival studies supporting a role for airborne transmission and the potential benefit of respirators (and other precautions designed to prevent inhalation of aerosols) versus surgical masks (mainly effective for reducing exposure to large droplets) to protect healthcare workers, more studies are needed to evaluate the extent of risk posed airborne versus contact and large droplet spray transmission modes. New human challenge-transmission studies should be carefully designed to overcome limitations encountered in the current study. The low secondary attack rate reported herein also suggests that the current challenge-transmission model may no longer be a more promising approach to resolving questions about transmission modes than community-based studies employing environmental monitoring and newer, state-of-the-art deep sequencing-based molecular epidemiological methods.

scholarly journals Vertical transmission of Prunus necrotic ringspot virus: hitch-hiking from gametes to seedling

2009 ◽  
Vol 90 (7) ◽  
pp. 1767-1774 ◽  
Author(s):  
Khalid Amari ◽  
Lorenzo Burgos ◽  
Vicente Pallás ◽  
Maria Amelia Sánchez-Pina
Keyword(s):  
Vertical Transmission ◽  
Developmental Stages ◽  
Embryo Sac ◽  
Reproductive Organs ◽  
Ringspot Virus ◽  
Reproductive Tissues ◽  
Hand Pollination ◽  
Prunus Necrotic Ringspot Virus ◽  
High Concentrations

The aim of this work was to follow Prunus necrotic ringspot virus (PNRSV) infection in apricot reproductive tissues and transmission of the virus to the next generation. For this, an analysis of viral distribution in apricot reproductive organs was carried out at different developmental stages. PNRSV was detected in reproductive tissues during gametogenesis. The virus was always present in the nucellus and, in some cases, in the embryo sac. Studies within infected seeds at the embryo globular stage revealed that PNRSV infects all parts of the seed, including embryo, endosperm and testa. In the torpedo and bent cotyledon developmental stages, high concentrations of the virus were detected in the testa and endosperm. At seed maturity, PNRSV accumulated slightly more in the embryo than in the cotyledons. In situ hybridization showed the presence of PNRSV RNA in embryos obtained following hand-pollination of virus-free pistils with infected pollen. Interestingly, tissue-printing from fruits obtained from these pistils showed viral RNA in the periphery of the fruits, whereas crosses between infected pistils and infected pollen resulted in a total invasion of the fruits. Taken together, these results shed light on the vertical transmission of PNRSV from gametes to seedlings.

scholarly journals Transmission mode is associated with environment type and taxa across bacteria-eukaryote symbioses

2018 ◽  
Author(s):  
Shelbi L Russell
Keyword(s):  
Vertical Transmission ◽  
Horizontal Transmission ◽  
Transmission Mode ◽  
Symbiotic Associations ◽  
Transmission Modes ◽  
Symbiont Transmission ◽  
Environment Type ◽  
Full Separation ◽  
Host Evolution ◽  
Host Tissues

AbstractSymbiotic associations between bacteria and eukaryotes exhibit a range of transmission strategies. Anecdotal observations suggest that symbionts of terrestrial hosts tend to be strictly vertically inherited through host tissues, whereas symbionts of marine hosts tend towards horizontal transmission. Aside from a few cursory investigations, the rates and distributions of transmission modes have not been investigated in depth across associations, despite the consequences for symbiont and host evolution. To address this empirically and estimate the rate of each mode, I compiled data from the literature and for associations between transmission mode and the environment, transmission route, symbiont function, and taxa involved in the symbiosis. Of the 441 analyzed symbioses, 50.1% were strictly vertically transmitted, 34.0% exhibited some form of mixed mode transmission, and 15.9% were strictly horizontally transmitted. Binning symbioses by their environment revealed a significant skew towards vertical transmission on land and horizontal transmission in aquatic environments, with mixed modes abundant in both. However, host and symbiont taxa were not randomly distributed, which prevented the full separation of these variables. Overall, the data suggest that many symbiotic taxa are capable of horizontal transmission and barriers exist that reduce the rate of these events. Thus, both the environment type and host/symbiont taxa combined influence symbiont transmission mode evolution.One sentence summaryThrough an intensive analysis of the literature on symbiosis transmission modes, estimated rates for each transmission mode were calculated, revealing bias for horizontal transmission in the ocean and vertical transmission on land.

scholarly journals First record of the endophytic bacteria of Deschampsia antarctica E. Desv. from two distant localities of the maritime Antarctica

2019 ◽  
Author(s):  
O. Podolich ◽  
I. Parnikoza ◽  
T. Voznyuk ◽  
G. Zubova ◽  
I. Zaets ◽  
...  
Keyword(s):  
Endophytic Bacteria ◽  
Vascular Plant ◽  
First Record ◽  
Deschampsia Antarctica ◽  
Rrna Gene ◽  
King George Island ◽  
Maritime Antarctica ◽  
Pcr Screening ◽  
Specific Pcr ◽  
The 16S Rrna Gene

AbstractThe vascular plant Deschampsia antarctica samples were collected for endophytic bacteria study from two regions in the maritime Antarctic 400 km distant from one another: Point Thomas oasis (King George Island) and Argentine Islands (Galindez Island). The endophytes were isolated from roots and leaves of D. antarctica, cultivated and identified by using a partial sequencing of the 16S rRNA gene served as a phylomarker. Endophyte isolates from two sites of Galindez Island were represented mainly by Pseudomonas species and by Gammaproteobacteria, Firmicutes and Actinobacteria. The vast majority of the isolates had specific for endophytes cellulase and pectinase activities, however, Bacillus spp. did not express both activities. A group-specific PCR screening at the four sites of Galindez Island and two sites of King George Island, indicated Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Firmicutes, Cytophaga-Flavobacteria and Actinobacteria. Notably, the number of endophytic bacteria taxa was significantly larger in leaves than in roots of plants.

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