Wolbachia are common intracellular bacteria that are found in arthropods and nematodes. These alphaproteobacteria endosymbionts are transmitted vertically through host eggs and alter host biology in diverse ways, including the induction of reproductive manipulations, such as feminization, parthenogenesis, male killing and sperm-egg incompatibility. They can also move horizontally across species boundaries, resulting in a widespread and global distribution in diverse invertebrate hosts. Here, we review the basic biology of Wolbachia, with emphasis on recent advances in our understanding of these fascinating endosymbionts.

We report here genome sequences and comparative analyses of three closely related parasitoid wasps: Nasonia vitripennis, N. giraulti, and N. longicornis. Parasitoids are important regulators of arthropod populations, including major agricultural pests and disease vectors, and Nasonia is an emerging genetic model, particularly for evolutionary and developmental genetics. Key findings include the identification of a functional DNA methylation tool kit; hymenopteran-specific genes including diverse venoms; lateral gene transfers among Pox viruses, Wolbachia, and Nasonia; and the rapid evolution of genes involved in nuclear-mitochondrial interactions that are implicated in speciation. Newly developed genome resources advance Nasonia for genetic research, accelerate mapping and cloning of quantitative trait loci, and will ultimately provide tools and knowledge for further increasing the utility of parasitoids as pest insect-control agents.

Although common among bacteria, lateral gene transfer-the movement of genes between distantly related organisms-is thought to occur only rarely between bacteria and multicellular eukaryotes. However, the presence of endosymbionts, such as Wolbachia pipientis, within some eukaryotic germlines may facilitate bacterial gene transfers to eukaryotic host genomes. We therefore examined host genomes for evidence of gene transfer events from Wolbachia bacteria to their hosts. We found and confirmed transfers into the genomes of 4 insect and 4 nematode species that range from nearly the entire Wolbachia genome (>1 megabase) to short (<500 base pairs) insertions. Potential Wolbachia to host transfers were also detected computationally in three additional sequenced insect genomes. We also show that some of these inserted Wolbachia genes are transcribed within eukaryotic cells lacking endosymbionts. Therefore, heritable lateral gene transfer occurs into eukaryotic hosts from their prokaryote symbionts, potentially providing a mechanism for acquisition of new genes and functions.

Abstract-This study examines the prevalence and coprevalence with which returning Operation Iraqi Freedom (OIF)/ Operation Enduring Freedom (OEF) veterans were reporting symptoms consistent with chronic pain, posttraumatic stress disorder (PTSD), and persistent postconcussive symptoms (PPCS). The medical records of 340 OIF/OEF veterans seen at a Department of Veterans Affairs Polytrauma Network Site were comprehensively reviewed. Analyses indicated a high prevalence of all three conditions in this population, with chronic pain, PTSD, and PPCS present in 81.5%, 68.2%, and 66.8%, respectively. Only 12 of the veterans (3.5%) had no chronic pain, PTSD, or PPCS. The frequency at which these three conditions were present in isolation (10.3%, 2.9%, and 5.3%, respectively) was significantly lower than the frequency at which they were present in combination with one another, with 42.1% of the sample being diagnosed with all three conditions simultaneously. The most common chronic pain locations were the back (58%) and head (55%). These results underscore the complexity of the presenting complaints in OIF/OEF veterans and support the importance of a multidisciplinary team approach to assessment and treatment.

Type-specific neutralization of the human immunodeficiency virus with antibodies to env-encoded synthetic peptides (

Wolbachia strains are endosymbiotic bacteria typically found in the reproductive tracts of arthropods. These bacteria manipulate host reproduction to ensure maternal transmission. They are usually transmitted vertically, so it has been predicted that they have evolved a mechanism to target the host's germ cells during development. Through cytological analysis we found that Wolbachia strains display various affinities for the germ line of Drosophila. Different Wolbachia strains show posterior, anterior, or cortical localization in Drosophila embryos, and this localization is congruent with the classification of the organisms based on the wsp (Wolbachia surface protein) gene sequence. This embryonic distribution pattern is established during early oogenesis and does not change until late stages of embryogenesis. The posterior and anterior localization of Wolbachia resembles that of oskar and bicoid mRNAs, respectively, which define the anterior-posterior axis in the Drosophila oocyte. By comparing the properties of a single Wolbachia strain in different host backgrounds and the properties of different Wolbachia strains in the same host background, we concluded that bacterial factors determine distribution, while bacterial density seems to be limited by the host. Possible implications concerning cytoplasmic incompatibility and evolution of strains are discussed.

Wolbachia infect a variety of arthropod and nematode hosts, but in arthropods, host phylogenetic relationships are usually poor predictors of strain similarity. This suggests that new infections are often established by horizontal transmission. To gain insight into the factors affecting the probability of horizontal transmission among host species, we ask how host phylogeny, geographical distribution and ecology affect patterns of Wolbachia strain similarity. We used multilocus sequence typing (MLST) to characterize Wolbachia strain similarity among dipteran hosts associated with fleshy mushrooms. Wolbachia Supergroup A was more common than Supergroup B in Diptera, and also more common in mycophagous than non-mycophagous Diptera. Within Supergroup A, host family within Diptera had no effect on strain similarity, and there was no tendency for Wolbachia strains from sympatric host species to be more similar to one another than to strains from hosts in different biogeographical realms. Supergroup A strains differed between mycophagous and non-mycophagous Diptera more than expected by chance, suggesting that ecological associations can facilitate horizontal transmission of Wolbachia within mycophagous fly communities. For Supergroup B, there were no significant associations between strain similarity and host phylogeny, biogeography, or ecology. We identified only two cases in which closely related hosts carried closely related Wolbachia strains, evidence that Wolbachia-host co-speciation or early introgression can occur but may not be a major contributor to overall strain diversity. Our results suggest that horizontal transmission of Wolbachia can be influenced by host ecology, thus leading to partial restriction of Wolbachia strains or strain groups to particular guilds of insects.

The purpose of this study was to examine the effects of recorded, preferred music in decreasing occurrences of aggressive behavior among individuals with Alzheimer's type dementia during bathing episodes. Eighteen older adults, age 55 to 95, with severe levels of cognitive impairment, participated in the study. They were randomly scheduled for observation during bath time under either a control (no music) condition or an experimental condition in which recorded selections of preferred music were played via audiotape recorder during the bathing episode. Following a 2-week (10 episode) observation period, conditions were reversed. A total of 20 observations were recorded for each individual. Results indicated that during the music condition, decreases occurred in 12 of 15 identified aggressive behaviors. Decreases were significant (p < 0.05) for the total number of observed behaviors and for hitting behaviors. During the music condition, caregivers frequently reported improved affect and a general increase in cooperation with the bathing task. The implications of these findings for improving the overall quality of care for severely cognitively impaired older adults are discussed.