- Reproductive Strategies
- Human Disease
- Speciation in Insects
- Vector Control
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- Wolbachia pipientis - Encyclopedia of Life (more info) This Encyclopedia of Life species page offers a comprehensive summary of the biology, ecology, evolution and relevance of Wolbachia pipientis. It includes an interactive media panel with images, videos and distribution maps, as well as a navigable classification structure. The page is supplemented with links to literature references, educational opportunities and additional research links.
- Biology of Wolbachia (more info) This overview paper discusses the biology of Wolbachia, including their phylogeny and distribution, mechanisms of action, population biology and evolution, and biological control implications. Potential directions for future
research are also discussed.
- Wolbachia - Wikipedia, the free encyclopedia (more info) This Wikipedia article features a brief overview of Wolbachia, including its history, role in sexual differentiation of hosts, horizontal gene transfer and applications to human health. A scientific classification is provided, as well as literature references and external links for additional information.
- Wolbachia: A Tale of Sex and Survival (more info) This Science news article reports how the ubiquitous bacterium Wolbachia--perhaps the most common infectious bacterium on Earth--boosts its own reproductive success by manipulating the sex lives of its hosts. It discusses the widespread distribution of this organism, clues about its role in the origination of new species, and potential applications in the fields of pest and disease control. A subscription to Science may be required to view this article.
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- Recombination confounds interpretations of Wolbachia evolution. (more info) This page contains a research article about Wolbachia evolution published in 2001. The authors present evidence of recombination between Wolbachia strains based on phylogenetic analyses. This addresses a major question in the field of Wolbachia research, and also provides an example of an unusual way in which to apply molecular phylogenetics data.The analyses and the writing are straightforward, making this paper accessible to undergraduate or higher level students.
- How Many Wolbachia Supergroups Exist? (more info) This is a brief article from Molecular Biology and Evolution (2002) on classification of Wolbachia by molecular phylogenetics. The introduction to the paper provides an overview of previous phylogenetic analyses and classification of Wolbachia into supergroups. The authors use additional taxonomic sampling of two different genes to address outstanding questions about the number of Wolbachia supergroups. This paper is a good example of using multiple data sources and statistical approaches to answer specific phylogenetic questions.
- Wolbachia: Evolutionary novelty in a rickettsial bacteria (more info) This is a research article on Wolbachia evolution published in BMC Evolutionary Biology in 2001. It presents a molecular phylogenetic study of Wolbachia, Ehrlichia, and Rickettsia. Two gene phylogenies were constructed and known life history traits were mapped onto the resulting trees in order to infer primitive/derived traits within the family Rickettsaceae. The paper is very brief and easy to read, and presents an interesting case of relating phenotype to genotype.
- From Parasite to Mutualist: Rapid Evolution of Wolbachia in Natural Populations of Drosophila (more info) This is a research paper on a case study in Wolbachia evolution published in PLoS Biology in 2007. The study takes advantage of a natural experiment - the spread of Wolbachia through California Drosophila populations - to test the hypothesis that maternal transmission favors evolution towards mutualism. This paper provides insight into Wolbachia biology, but also a case study for a broader evolutionary principle.
The male blue moon butterfly has evolved to be resistant to the sex-selective Wolbachia. Image in public domain.
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- Bizarre parasite that kills male insects and disrupts insect sex lives is not all bad: it can make sterile fruit flies fertile again ( This site may be offline. ) Researchers at UC Berkely discover that the bacterium Wolbachia pipientis allows a sterile female fruit fly to lay eggs, circumventing a genetic mutation in a gene that is the key to determining the sex of offspring, reports this campus news article. The article introduces the sex-lethal gene, Sxl, and offers a discussion of sex determination in Drosophila.
- But Madame Butterfly, Where Are All the Males? (more info) This Scientific American article reports that a population of Samoan blue moon butterflies has been able to develop resistance to the male-killing bacteria Wolbachia. It explores how an introduced suppressor gene allowed resistant males to proliferate within the population in less than a year and includes future research questions.
- Wolbachia, widowmaker (more info) This Nature news article explores the range of anti-male activity mediated by Wolbachia. Inherited and widespread among insects and other arthropods, Wolbachia infections impact both the sex-lives and evolution of their hosts. A subscription to Nature may be necessary to access this article.
Symbiosis & Host-Microbe Interactions
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- Parasite Invades Its Host's DNA (more info) Number 73 out of the top 100 science stories of 2007, this article highlights the ability of Wolbachia bacteria to transfer nearly their entire genome into the cells of a multicellular host. The article offers an overview of the related research as well as a link to the primary literature.
- One Species' Genome Discovered Inside Another's (more info) According to this online article, scientists have discovered a copy of the genome of the bacterial parasite Wolbachia residing inside the genome of its host species. It explains that lateral gene transfer may happen much more frequently than previously believed. The article includes a discussion of the research with downloadable high-resolution images and a video of Professor Jack Werren describing the results.
- The parasitic bacterium Wolbachia and the origin of the eukaryotic cell (more info) This scientific abstract analyzes the relationships between eukaryotes and alphaproteobacteria, specifically Wolbachia pipientis, as a key in understanding the rise of mitochondria leading to the origin of the eukaryotic cell. It compares and contrasts Wolbachia and mitochondria, leading to a discussion of lateral gene transfer in the evolution of proto-eukaryotes. The full article is available in PDF format and may require a subscription to the Paleontological Journal.
Elephantiasis of leg due to filariasis. Luzon, Philippines. Image in public domain, courtesy of the CDC.
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- A-WOL - Anti-Wolbachia Consortium (more info) Funded by the Bill and Melinda Gates Foundation, the A∙WOL Consortium consists of both academic and industrial partners whose aim is to develop a new chemotherapy treatment against Wolbachia - a bacterial endosymbiont of filarial nematodes responsible for onchocerciasis (river blindness) and lymphatic filariasis (elephantiasis). This portal features an overview of the programme and its partners, latest news releases, upcoming meetings and a list of related articles. It also includes descriptive pages about onchocerciasis and lymphatic filariasis.
- Worms' bacteria main cause of river blindness - Parasites - medical research (more info) This news article reports that Wolbachia may play a role in river blindness, the second-leading infectious cause of blindness in the world. While the disease is caused by parasitic worms that burrow into the skin, researchers discovered that treating the worms of their Wolbachia infections with doxycycline led to significantly less thickening and haze of the eye's cornea.
- Africa: One step nearer to cure for river blindness (more info) This United Nations news article reports that it is actually the bacteria inside parasitic worms, and not the worms themselves, that cause river blindness. The article discusses the symptoms of onchocerciasis and introduces a potential cure for the disease, antibiotics targeting Wolbachia.
- Targeting wolbachia, doxycycline reduces pathology of lymphatic filariasis (more info) This news brief highlights findings from a PLoS Pathogens paper, which reported that lymphatic filariasis can be treated by targeting the endosymbiont Wolbachia with the antibiotic doxycycline. The article includes a short overview of the experiment leading to these results.
- Doxycycline Reduces Plasma VEGF-C/sVEGFR-3 and Improves Pathology in Lymphatic Filariasis (more info) According to this PLoS Pathogens paper, doxycycline is able to kill adult worms responsible for lymphatic filariasis, thus improving lymphatic vessel dilation and significantly ameliorating the conditions of lymphedema patients. The paper describes the specific role of Wolbachia in this disease and presents results from a placebo-controlled, double-blind study in Ghana.
- New Culprit Emerges in River Blindness (more info) This Science news article introduces a 2002 publication in which an international team of researchers determined that the bacterial symbiont Wolbachia might be the real culprit in river blindness. While the disease is transmitted by a parasitic nematode, studies have shown that 'curing' the worm of its Wolbachia infection with antibiotics suppresses the severe immune system response, which slowly robs people of their vision. The article discusses the collaborative research effort and indicates that more studies are needed to fully understand the role this finding may have in stopping the spread of the disease.
Speciation in Insects
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- Bacterium Can Alter Evolution Of Another Species (more info) This Daily University Science News article reviews scientific evidence that the parasitic bacterium Wolbachia can accelerate the natural evolution of wasps by altering the sperm of its male host, thus making them incompatible with non-infected females. The article discusses this evidence as well as introduces a current debate about Wolbachia's role in host speciation.
- Bacteria Spurs Speciation (more info) This brief Scientific American article reports that the infectious bacterium Wolbachia has been shown to serve as a reproductive barrier in wasps, thus keeping species reproductively separated in nature and promoting host speciation.
- Infection Divides Two Wasp Species (more info) Giving antibiotics to tiny wasps to cure them of a sex-related disease reveals the best evidence yet that infections can help make new species, reports this news article. Based on the research of Seth Bordenstein and Jack Werren, this article discusses reproductive barriers in Nasonia wasp species and summarizes the effect of treating these wasps with antibiotics targeting their Wolbachia infections.
- Speciation and Wolbachia (more info) This scientific article offers a comprehensive overview of Wolbachia and its role in speciation. Sections include: What Wolbachia is; What Wolbachia Does to Its Host; Wolbachia &amp;amp;amp;ndash; a Reproductive Parasite of Arthropods; Models for CI (Cytoplasmic Incompatibility); Theory of Coevolution of Wolbachia and Host Insect; Likely (Theoretical) Role of Wolbachia in Speciation; Drosophila as a Case Study; and What Defines a Strain of Wolbachia. A subscription to the Encyclopedia of Life Sciences may be required to view this article.
- Evolution: Infectious Speciation ( This site may be offline. ) This Nature news article summarizes reports that the infectious bacterium Wolbachia acts as a reproductive barrier to gene exchange in its host. The article reviews the nature of Wolbachia and introduces its role in cytoplasmic incompatibility, a phenomenon which results in the failure of infected host males and uninfected host females to produce offspring. A subscription to Nature may be required to view this article.
- Wolbachia and Wasp Evolution (more info) This Science news brief summarizes the startling effect that Wolbachia have on the reproduction of their insect hosts. It offers an overview of cytoplasmic incompatibility and its role in reproductive isolation. Findings from this research have led biologists to speculate that Wolbachia may contribute to reproductive isolation and the creation of new insect species (speciation). A subscription to Science may be required to view this article.
Malaria is transmitted when a female Anopheles mosquito takes a blood meal. Image in public domain, courtesy of the CDC .
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- Bacterial parasite shows potential in disease control (more info) This online article reports that researchers have sequenced the complete genome of one strain of Wolbachia pipientis and are gaining new insight into the biology and evolution of Wolbachia-host interactions. It discusses practical applications such as disease and pest control.
- Mosquito age and dengue transmission (more info) This online portal features a research project funded by The Grand Challenges in Global Health Initiative to develop new strategies to control mosquitoes that transmit human disease. Specifically, the project is focused on a method to reduce dengue transmission using naturally occurring bacterial symbionts that reduce mosquito life span. The site includes a background of this work, participating research programs and researchers, project publications, current progress, news and events, and FAQs.
- Study raises malaria block hopes (more info) This BBC news article reports that scientists have made a key breakthrough in understanding the genetics of Wolbachia, a parasite they hope could be used to block the spread of malaria. The article offers a brief overview of malaria and Wolbachia, and then focuses on the use of transgenic Wolbachia as a way of modifying natural populations of insects which transmit disease.
- Can Wolbachia help prevent the spread of malaria? ( This site may be offline. ) This online article discusses international research aimed at developing malaria control strategies using genetically modified Wolbachia that would spread through mosquito populations and carry genes that make their mosquito hosts unable to transmit the Plasmodium parasite that causes malaria. The article reviews the biology of Wolbachia, its effect on host reproduction, and genetic mechanisms of cytoplasmic incompatibility.
Viruses/Phage: The Parasites Within
Wolbachia bacteria infected with numerous tiny virus particles, enlarged in the inset. Image by Michelle Gourley and Seth Bordenstein, courtesy of the Encyclopedia of Life.
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- Viral hitchhiker inhibits Wolbachia bacteria's ability to proliferate (more info) This online news brief highlights a recent study that showed a virus common to Wolbachia cells may be a key inhibitor of the cellular process that allows Wolbachia to manipulate insect reproduction. The article explains the major findings of this study as well as the implications it could have on global strategies to control insect-borne diseases.
- The Tripartite Associations between Bacteriophage, Wolbachia, and Arthropods (more info) This research paper describes a set of quantitative approaches to characterizing phage densities and its associations with bacterial densities and cytoplasmic incompatibility (CI) within Wolbachia. The findings motivate a novel phage density model of CI in which lytic phage repress Wolbachia densities and therefore reproductive parasitism. The paper concludes that phage, Wolbachia, and arthropods form a tripartite symbiotic association in which all three are integral to understanding the biology of this widespread endosymbiosis.
- Symbiotic enemies fight over insect (more info) This online news article reports that bacteriophage affects the control Wolbachia has over host reproduction, particularly the processes of cytoplasmic incompatibility (CI) in which infected males are unable to mate with uninfected females. The finding adds to the complexity of multi-layered symbioses. Links are provided to the primary literature as well as supplemental articles and individual research programs. A subscription to The Scientist may be required to access this article.