PKCε contributes to lipid-induced insulin resistance through cross talk with p70S6K and through previously unknown regulators of insulin signaling.

Insulin resistance drives the development of type 2 diabetes (T2D). In liver, diacylglycerol (DAG) is a key mediator of lipid-induced insulin resistance. DAG activates protein kinase C ε (PKCε), which phosphorylates and inhibits the insulin receptor. In rats, a 3-day high-fat diet produces hepatic insulin resistance through this mechanism, and knockdown of hepatic PKCε protects against high-fat diet-induced hepatic insulin resistance. Here, we employed a systems-level approach to uncover additional signaling pathways involved in high-fat diet-induced hepatic insulin resistance. We used quantitative phosphoproteomics to map global in vivo changes in hepatic protein phosphorylation in chow-fed, high-fat-fed, and high-fat-fed with PKCε knockdown rats to distinguish the impact of lipid- and PKCε-induced protein phosphorylation. This was followed by a functional siRNA-based screen to determine which dynamically regulated phosphoproteins may be involved in canonical insulin signaling. Direct PKCε substrates were identified by motif analysis of phosphoproteomics data and validated using a large-scale in vitro kinase assay. These substrates included the p70S6K substrates RPS6 and IRS1, which suggested cross talk between PKCε and p70S6K in high-fat diet-induced hepatic insulin resistance. These results identify an expanded set of proteins through which PKCε may drive high-fat diet-induced hepatic insulin resistance that may direct new therapeutic approaches for T2D.

Identification of small molecule inhibitors of Jumonji AT-rich interactive domain 1B (JARID1B) histone demethylase by a sensitive high throughput screen.

JARID1B (also known as KDM5B or PLU1) is a member of the JARID1 family of histone lysine demethylases responsible for the demethylation of trimethylated lysine 27 in histone H3 (H3K4me3), a mark for actively transcribed genes. JARID1B is overexpressed in several cancers, including breast cancer, prostate cancer, and lung cancer. In addition, JARID1B is required for mammary tumor formation in syngeneic or xenograft mouse models. JARID1B-expressing melanoma cells are associated with increased self-renewal character. Therefore, JARID1B represents an attractive target for cancer therapy. Here we characterized JARID1B using a homogeneous luminescence-based demethylase assay. We then conducted a high throughput screen of over 15,000 small molecules to identify inhibitors of JARID1B. From this screen, we identified several known JmjC histone demethylase inhibitors, including 2,4-pyridinedicarboxylic acid and catechols. More importantly, we identified several novel inhibitors, including 2-4(4-methylphenyl)-1,2-benzisothiazol-3(2H)-one (PBIT), which inhibits JARID1B with an IC50 of about 3 µm in vitro. Consistent with this, PBIT treatment inhibited removal of H3K4me3 by JARID1B in cells. Furthermore, this compound inhibited proliferation of cells expressing higher levels of JARID1B. These results suggest that this novel small molecule inhibitor is a lead compound that can be further optimized for cancer therapy.

MKK3 regulates mitochondrial biogenesis and mitophagy in sepsis-induced lung injury.

Sepsis is a systemic inflammatory response to infection and a major cause of death worldwide. Because specific therapies to treat sepsis are limited, and underlying pathogenesis is unclear, current medical care remains purely supportive. Therefore targeted therapies to treat sepsis need to be developed. Although an important mediator of sepsis is thought to be mitochondrial dysfunction, the underlying molecular mechanism is unclear. Modulation of mitochondrial processes may be an effective therapeutic strategy in sepsis. Here, we investigated the role of the kinase MKK3 in regulation of mitochondrial function in sepsis. Using clinically relevant animal models, we examined mitochondrial function in primary mouse lung endothelial cells exposed to LPS. MKK3 deficiency reduces lethality of sepsis in mice and by lowering levels of lung and mitochondrial injury as well as reactive oxygen species. Furthermore, MKK3 deficiency appeared to simultaneously increase mitochondrial biogenesis and mitophagy through the actions of Sirt1, Pink1, and Parkin. This led to a more robust mitochondrial network, which we propose provides protection against sepsis. We also detected higher MKK3 activation in isolated peripheral blood mononuclear cells from septic patients compared with nonseptic controls. Our findings demonstrate a critical role for mitochondria in the pathogenesis of sepsis that involves a previously unrecognized function of MKK3 in mitochondrial quality control. This mitochondrial pathway may help reveal new diagnostic markers and therapeutic targets against sepsis.

Diagnostic Use of Lactate in Exotic Animals.

Monitoring blood lactate concentrations with a handheld, point-of-care (POC) meter is an efficient and inexpensive method of monitoring critically ill or anesthetized exotic patients. Serial monitoring of lactate allows early recognition of hypoperfusion, allowing for prompt implementation of resuscitative efforts. Reference ranges for exotic animals are currently sparse and often gathered from field studies of wild animals. In the absence of reference ranges, extrapolations can be made regarding mammals and birds, but may be more difficult in reptiles and amphibians.

Expression profiling using a hexamer-based universal microarray.

We describe a transcriptional analysis platform consisting of a universal micro-array system (UMAS) combined with an enzymatic manipulation step that is capable of generating expression profiles from any organism without requiring a priori species-specific knowledge of transcript sequences. The transcriptome is converted to cDNA and processed with restriction endonucleases to generate low-complexity pools (approximately 80-120) of equal length DNA fragments. The resulting material is amplified and detected with the UMAS system, comprising all possible 4,096 (4(6)) DNA hexamers. Ligation to the arrays yields thousands of 14-mer sequence tags. The compendium of signals from all pools in the array-of-universal arrays comprises a full-transcriptome expression profile. The technology was validated by analysis of the galactose response of Saccharomyces cerevisiae, and the resulting profiles showed excellent agreement with the literature and real-time PCR assays. The technology was also used to demonstrate expression profiling from a hybrid organism in a proof-of-concept experiment where a T-cell receptor gene was expressed in yeast.

Microfilariae in Galápagos penguins (Spheniscus mendiculus) and flightless cormorants (Phalacrocorax harrisi): genetics, morphology, and prevalence.

Galapagos penguins (Spheniscus mendiculus) and flightless cormorants (Phalacrocorax harrisi) live in small, isolated populations on the westernmost islands of Isabela and Fernandina in the Galápagos Islands, Ecuador. Between August 2003 and February 2005, 4 field trips, 2 in the cool, dry season (August 2003 and August 2004) and 2 in the hot, rainy season (March 2004 and February 2005), were undertaken; 298 Galápagos penguins and 380 cormorants were sampled for prevalence and intensity of hemoparasites. Microfilariae were found in both the penguins and the cormorants. Blood smears were negative for the presence of other species of hemoparasites. Overall prevalence of microfilariae across seasons was 42.0% in cormorants and 13.8% in the penguins. Intensity of infection was generally low (mean = 3.2-31.7 in 25 fields across seasons and species) with the exception of a few individuals with markedly high intensities of parasites (>300 in 25 fields in 1 cormorant). Prevalence of microfilariae increased significantly over the 4 sampling periods for cormorants, but not for penguins. Prevalences were significantly higher in cormorants than in penguins for 3 of the 4 collecting trips. Male penguins had higher prevalences than females; however, there were no gender differences in cormorants. No relation was detected between body mass and either presence or intensity of parasitism. Morphological characteristics of the microfilariae are also described and specimens from each host species were similar in all characters measured. DNA sequence data from the mitochondrial cytochrome c oxidase subunit I gene were consistent with the morphological evidence and together demonstrate that the penguins and cormorants are likely to be infected with the same species of microfilariae.

Macrolides selectively inhibit mutant KCNJ5 potassium channels that cause aldosterone-producing adenoma.

Aldosterone-producing adenomas (APAs) are benign tumors of the adrenal gland that constitutively produce the salt-retaining steroid hormone aldosterone and cause millions of cases of severe hypertension worldwide. Either of 2 somatic mutations in the potassium channel KCNJ5 (G151R and L168R, hereafter referred to as KCNJ5MUT) in adrenocortical cells account for half of APAs worldwide. These mutations alter channel selectivity to allow abnormal Na+ conductance, resulting in membrane depolarization, calcium influx, aldosterone production, and cell proliferation. Because APA diagnosis requires a difficult invasive procedure, patients often remain undiagnosed and inadequately treated. Inhibitors of KCNJ5MUT could allow noninvasive diagnosis and therapy of APAs carrying KCNJ5 mutations. Here, we developed a high-throughput screen for rescue of KCNJ5MUT-induced lethality and identified a series of macrolide antibiotics, including roxithromycin, that potently inhibit KCNJ5MUT, but not KCNJ5WT. Electrophysiology demonstrated direct KCNJ5MUT inhibition. In human aldosterone-producing adrenocortical cancer cell lines, roxithromycin inhibited KCNJ5MUT-induced induction of CYP11B2 (encoding aldosterone synthase) expression and aldosterone production. Further exploration of macrolides showed that KCNJ5MUT was similarly selectively inhibited by idremcinal, a macrolide motilin receptor agonist, and by synthesized macrolide derivatives lacking antibiotic or motilide activity. Macrolide-derived selective KCNJ5MUT inhibitors thus have the potential to advance the diagnosis and treatment of APAs harboring KCNJ5MUT.

DNA Polymerase Beta Germline Variant Confers Cellular Response to Cisplatin Therapy.

Resistance to cancer chemotherapies leads to deadly consequences, yet current research focuses only on the roles of somatically acquired mutations in this resistance. The mutational status of the germline is also likely to play a role in the way cells respond to chemotherapy. The carrier status for the POLB rs3136797 germline mutation encoding P242R DNA polymerase beta (Pol ß) is associated with poor prognosis for lung cancer, specifically in response to treatment with cisplatin. Here, it is revealed that the P242R mutation is sufficient to promote resistance to cisplatin in human cells and in mouse xenografts. Mechanistically, P242R Pol ß acts as a translesion polymerase and prefers to insert the correct nucleotide opposite cisplatin intrastrand cross-links, leading to the activation of the nucleotide excision repair (NER) pathway, removal of crosslinks, and resistance to cisplatin. In contrast, wild-type (WT) Pol ß preferentially inserts the incorrect nucleotide initiating mismatch repair and cell death. Importantly, in a mouse xenograft model, tumors derived from lung cancer cells expressing WT Pol ß displayed a slower rate of growth when treated with cisplatin, whereas tumors expressing P242R Pol ß had no response to cisplatin. Pol ß is critical for mediating crosstalk in response to cisplatin. The current data strongly suggest that the status of Pol ß influences cellular responses to crosslinking agents and that Pol ß is a promising biomarker to predict responses to specific chemotherapies. Finally, these results highlight that the genetic status of the germline is a critical factor in the response to cancer treatment.Implications: Pol ß has prognostic biomarker potential in the treatment of cancer with cisplatin and perhaps other intrastrand crosslinking agents. Mol Cancer Res; 15(3); 269-80. ©2017 AACR.

Cryptic host specificity of an avian skin mite (Epidermoptidae) vectored by louseflies (Hippoboscidae) associated with two endemic Galapagos bird species.

Host specificity of vectors is an important but understudied force shaping parasite evolution and the relationship between hosts and parasites. Low vector specificity may allow a vectored parasite to invade new host species, whereas high specificity of vectors may reduce the host range of the parasite and favor specialization. The 'generalist' and widely distributed avian skin mite Myialges caulotoon Speiser (Acari: Epidermoptidae) is unusual because females require an insect vector to complete their life cycle. Myialges caulotoon was previously reported from 2 lousefly (Diptera: Hippoboscidae) species, Olfersia sordida and Icosta nigra, parasitizing flightless cormorants (Phalacrocorax harrisi) and Galápagos hawks (Buteo galapagoensis), respectively, within the Galápagos Islands. This is a surprising distribution, given that the 2 lousefly species involved are relatively host-specific. Mitochondrial DNA sequences revealed 2 reciprocally monophyletic Myialges clades that sorted out perfectly with respect to their vector species, regardless of whether they were in allopatry or sympatry. One clade was restricted to flies of hawks and the other to flies of cormorants. Females of the 2 Myialges groups were also separated consistently by the shape of the sternal surface sclerotization. Mites of hawk flies were more abundant than those of cormorant flies. Within the Myialges clade associated with hawks, genetic differentiation between 2 island populations mirrored its host's patterns of differentiation.

Hematology, serum chemistry, and serology of Galápagos penguins (Spheniscus mendiculus) in the Galápagos Islands, Ecuador.

The Galápagos penguin (Spheniscus mendiculus) is an endangered species endemic to the Galápagos Islands, Ecuador. In 2003 and 2004, 195 penguins from 13 colonies on the islands of Isabela and Fernandina in the Galápagos archipelago were examined. Genetic sexing of 157 penguins revealed 62 females and 95 males. Hematology consisted of packed cell volume (n = 134), white blood cell differentials (n = 83), and hemoparasite blood smear evaluation (n = 114). Microfilariae were detected in 22% (25/114) of the blood smears. Female penguins had significantly higher eosinophil counts than males. Serum chemistry on 83 penguins revealed no significant differences between males and females. Birds were seronegative to avian paramyxovirus type 1-3, avian influenza virus, infectious bursal disease virus, Marek's disease virus (herpes), reovirus, avian encephalomyelitis virus, and avian adenovirus type 1 and 2 (n = 75), as well as to West Nile virus (n = 87), and Venezuelan, western and eastern equine encephalitis viruses (n = 26). Seventy-five of 84 (89%) penguins had antibodies to Chlamydophila psittaci but chlamydial DNA was not detected via polymerase chain reaction in samples from 30 birds.

Hematology, plasma chemistry, and serology of the flightless cormorant (Phalacrocorax harrisi) in the Galapagos Islands, Ecuador.

The flightless cormorant (Phalacrocorax harrisi) is an endemic species of the Galápagos Islands, Ecuador. Health studies of the species have not previously been conducted. In August 2003, baseline samples were collected from flightless cormorant colonies on the islands of Isabela and Fernandina. Seventy-six birds, from nestlings to adults, were evaluated. Genetic sexing of 70 cormorants revealed 37 females and 33 males. Hematology assessment consisted of packed cell volume (n=19), leukograms (n=69), and blood smear evaluation (n=69). Microscopic evaluation of blood smears revealed microfilaria in 33% (23/69) of the cormorants. Plasma chemistries were performed on 46 cormorants. There was no significant difference in chemistry values or complete blood counts between male and female cormorants or between age groups. Based on a serologic survey to assess exposure to avian pathogens, birds (n=69) were seronegative for West Nile virus, avian paramyxovirus type 1 (Newcastle disease virus), avian paramyxovirus types 2 and 3, avian influenza, infectious bursal disease, infectious bronchitis, Marek's disease (herpes), reovirus, avian encephalomyelitis, and avian adenovirus type 2. Antibodies to avian adenovirus type 1 and Chlamydophila psittaci were found in 31% (21/68) and 11% (7/65) of flightless cormorants respectively. Chlamydophila psittaci was detected via polymerase chain reaction in 6% (2/33) of the cormorants. The overall negative serologic findings of this research suggest that the flightless cormorant is an immunologically naïve species, which may have a reduced capacity to cope with the introduction of novel pathogens.

Screen-identified selective inhibitor of lysine demethylase 5A blocks cancer cell growth and drug resistance.

Lysine demethylase 5A (KDM5A/RBP2/JARID1A) is a histone lysine demethylase that is overexpressed in several human cancers including lung, gastric, breast and liver cancers. It plays key roles in important cancer processes including tumorigenesis, metastasis, and drug tolerance, making it a potential cancer therapeutic target. Chemical tools to analyze KDM5A demethylase activity are extremely limited as available inhibitors are not specific for KDM5A. Here, we characterized KDM5A using a homogeneous luminescence-based assay and conducted a screen of about 9,000 small molecules for inhibitors. From this screen, we identified several 3-thio-1,2,4-triazole compounds that inhibited KDM5A with low µM in vitro IC50 values. Importantly, these compounds showed great specificity and did not inhibit its close homologue KDM5B (PLU1/JARID1B) or the related H3K27 demethylases KDM6A (UTX) and KDM6B (JMJD3). One compound, named YUKA1, was able to increase H3K4me3 levels in human cells and selectively inhibit the proliferation of cancer cells whose growth depends on KDM5A. As KDM5A was shown to mediate drug tolerance, we investigated the ability of YUKA1 to prevent drug tolerance in EGFR-mutant lung cancer cells treated with gefitinib and HER2+ breast cancer cells treated with trastuzumab. Remarkably, this compound hindered the emergence of drug-tolerant cells, highlighting the critical role of KDM5A demethylase activity in drug resistance. The small molecules presented here are excellent tool compounds for further study of KDM5A's demethylase activity and its contributions to cancer.

Assessing the risks of introduced chickens and their pathogens to native birds in the Galápagos Archipelago.

Poultry production is an important economic activity on inhabited islands of the Galápagos archipelago. There has been a recent surge in both small-scale backyard chickens and larger scale broiler production associated with growth in the human population and the tourist industry. With increased poultry production, concerns have been expressed about the increasing risk of transfer of disease from chickens to native Galápagos bird species that may have little resistance to introduced pathogens [Wikelski, M., Foufopoulos, J., Vargas, H., Snell, H., 2004. Galápagos birds and diseases: invasive pathogens as threats for island species. Ecology and Society 9(5). Available from: URL:http://www.ecologyandsociety.org/vol9/iss1/art5]. This study evaluates risks posed by chicken disease to endemic and native Galápagos bird species, based on empirical evidence of pathogens present in chickens on the islands and a literature review of effects of these pathogens in wild species. Pathogens identified in domestic chicken populations of immediate avian conservation concern are Newcastle disease, Mycoplasma gallisepticum, and the proventricular parasite Dispharynx sp. Newcastle disease (avian paramyxovirus-1) poses an imminent threat to Galápagos penguins (Spheniscus mendiculus), flightless cormorants (Phalacrocorax harrisi), and lava gulls (Larus fuliginosus), species with very small population sizes (less than 1500 animals each). Additionally, litter from broiler farms could affect ecological processes in local ecosystems. Improved poultry biosecurity measures are urgently needed on the Galápagos Islands for avian disease management, yet developing these strategies presents political, social, and economic challenges.

Hematology, plasma chemistry, serology, and Chlamydophila status of the waved albatross (Phoebastria irrorata) on the Galapagos Islands.

Venipuncture was performed on 50 adult, free-ranging waved albatrosses (Phoebastria irrorata) on Española, Galapagos Islands, Ecuador, to establish hematologic and plasma biochemistry reference ranges and to determine the prevalence of exposure to important domestic avian pathogens. Weights and plasma creatine phosphokinase activities differed significantly between males and females. Serum was tested for evidence of exposure to avian influenza, avian paramyxoviruses 1, 2, and 3, avian cholera, adenovirus groups 1 and 2, avian encephalomyelitis, Marek's disease, infectious bursal disease, and infectious bronchitis virus (Connecticut and Massachusetts strains). Of 44 birds, 29 (66%) seroreacted to adenovirus group 1, and four seroreacted to avian encephalomyelitis. Cloacal swabs were negative for Chlamydophila psittaci DNA.

Survey for Haemoproteus spp., Trichomonas gallinae, Chlamydophila psittaci, and Salmonella spp. in Galapagos Islands columbiformes.

Endemic free-ranging Galapagos doves (Zenaida galapagoensis) and introduced rock doves (Columba livia) were surveyed in several islands of the Galapagos archipelago to establish sample prevalence of hemoparasites, Trichomonas gallinae, Chlamydophila psittaci, and Salmonella species. A Haemoproteus sp., the only hemoparasite identified, was found in 89% of the Galapagos doves sampled but not in the rock doves. Trichomonas gallinae was detected by polymerase chain reaction in 44% of rock doves from San Cristobal but in none of the Galapagos doves. Chlamydophila psittaci was detected from cloacal swabs in 6% of the Galapagos doves but in none of the rock doves sampled. All positive cases of C. psittaci occurred on Española, where the crude sample prevalence was 24%. A polymerase chain reaction-based Salmonella test failed to show evidence of this organism from any birds sampled.

Comparison of blood values and health status of Floreana Mockingbirds (Mimus trifasciatus) on the islands of Champion and Gardner-by-Floreana, Galápagos Islands.

The Floreana Mockingbird (Mimus trifasciatus) is one of the rarest bird species in the world, with an estimated 550 individuals remaining on two rocky islets off the coast of Floreana, Galápagos, Ecuador, from which the main population was extirpated more than 100 yr ago. Because they have been listed in critical danger of extinction, a plan to reintroduce this species to Floreana has been initiated. Determining the health status of the source mockingbird populations is a top priority within the reintroduction plan. We report the health status, over the course of 4 yr, of 75 Floreana Mockingbirds on Champion Island and 160 Floreana Mockingbirds on Gardner-by-Floreana, based on physical examinations, hematology, hemolysis-hemagglutination assay, exposure to selected infectious disease agents, and ecto- and endoparasite counts. Birds on Gardner-by-Floreana had higher body condition index scores, packed cell volumes, total solids, and lymphocyte counts. Additionally, Gardner-by-Floreana birds had lower heterophil counts, eosinophil counts, and heterophil:lymphocyte ratios. No Chlamydophila psittaci DNA or antibodies to paramyxovirus-I, adenovirus-II, or Mycoplasma gallisepticum were found in any of the mockingbirds tested. Ectoparasites were present on birds from both islands, although species varied between islands. A coccidian species was found in eight of the 45 fecal samples from birds on Gardner-by-Floreana, but none of 33 birds examined from Champion. Birds on Gardner-by-Floreana were classified as healthier than those on Champion based on clinical and laboratory findings. These health data will be analyzed in conjunction with genetics, population structure, and disease presence on Floreana for developing recommendations for the Floreana Mockingbird reintroduction plan.

Drug repositioning and pharmacophore identification in the discovery of hookworm MIF inhibitors.

The screening of bioactive compound libraries can be an effective approach for repositioning FDA-approved drugs or discovering new pharmacophores. Hookworms are blood-feeding, intestinal nematode parasites that infect up to 600 million people worldwide. Vaccination with recombinant Ancylostoma ceylanicum macrophage migration inhibitory factor (rAceMIF) provided partial protection from disease, thus establishing a "proof-of-concept" for targeting AceMIF to prevent or treat infection. A high-throughput screen (HTS) against rAceMIF identified six AceMIF-specific inhibitors. A nonsteroidal anti-inflammatory drug (NSAID), sodium meclofenamate, could be tested in an animal model to assess the therapeutic efficacy in treating hookworm disease. Furosemide, an FDA-approved diuretic, exhibited submicromolar inhibition of rAceMIF tautomerase activity. Structure-activity relationships of a pharmacophore based on furosemide included one analog that binds similarly to the active site, yet does not inhibit the Na-K-Cl symporter (NKCC1) responsible for diuretic activity.

Ecological correlates of microfilariae prevalence in endangered Galápagos birds.

This study assesses the ecological factors associated with microfilariae prevalence in wild populations of endangered flightless cormorants (Phalacrocorax harrisi) and Galápagos penguins (Spheniscus mendiculus). Prevalence values were tested for correlation with a large number of environmental variables, as modeled from weather station data and measured by satellite-borne sensors. Predictions were made based on the expected effects of climatic and landscape variables on sustained populations of arthropod vectors required for transmission of microfilariae. In general, findings were consistent with predictions in both cormorants and penguins; prevalence correlated positively with temperature, precipitation, and vegetation density, and negatively with measures of environmental variability. Resulting correlates were used to derive predictive distributions of prevalence values in cormorants throughout the archipelago. Evidence is presented implicating the mosquito Aedes taeniorhynchus as a likely vector. Knowledge of environmental variables that predict risk of disease transmission by arthropod vectors may be useful in control measures should novel pathogens be introduced to the ecosystem.

Exposure to Toxoplasma gondii in Galapagos Penguins (Spheniscus mendiculus) and flightless cormorants (Phalacrocorax harrisi) in the Galapagos Islands, Ecuador.

Toxoplasma gondii is one of the most common protozoan parasites of humans and warm-blooded animals. Members of the family Felidae are the only definitive hosts of this parasite and, thus, important in the epidemiology of the disease. Previous studies on Pacific islands have found T. gondii infections in a number of avian species where domestic cats (Felis catus) have been introduced. Little is known about T. gondii in the Galapagos Islands, although introduced domestic cats in the archipelago are known to be T. gondii antibody-positive. In this study, we quantified prevalence of antibody to T. gondii in two threatened avian marine species, Galapagos Penguins (Spheniscus mendiculus) and Flightless Cormorants (Phalacrocorax harrisi), and tested the hypothesis that this parasite is more prevalent on Isabela Island (with cats) than on Fernandina Island (without cats). Overall, antibody prevalence was 2.3% in both Galapagos Penguins and Flightless Cormorants from samples collected during 2003-2005, and in 2008. In Galapagos Penguins (n=298), a significantly higher antibody prevalence was found in penguins on Fernandina Island (free of cats) than on Isabela Island (with cats; Fisher's exact test; P=0.02). In Flightless Cormorants (n=258), there was a higher antibody prevalence in cormorants living on Isabela than on Fernandina, although this difference was not statistically significant (Fisher's; P=0.19). This study is the first to show exposure to T. gondii in endemic avian species in the Galapagos Islands, providing evidence for disease-related risks associated with the feral cat population in the archipelago. We provide possible explanations for these findings and recommendations for future studies towards a better understanding of the epidemiology of T. gondii in the Galapagos Islands.

IS1096-mediated DNA rearrangements play a key role in genome evolution of Mycobacterium smegmatis.

The acquisition of DNA and the loss of genetic information are two important mechanisms that contribute to strain-specific differences in genome content. In this study, comparative genomics has allowed us to infer the roles of genomic rearrangement and changes in both distribution and copy number of the insertion element, IS1096, in the evolution of Mycobacterium smegmatis mc2155 from its progenitor, M. smegmatis ATCC 607. Comparative analysis revealed that the ATCC 607 genome contains only 11 IS1096 elements against the 24 reported in mc2155. As mc2155 evolved, there was a considerable expansion in the copy number of IS1096 (+13) as well as duplication of a 56-kb fragment flanked on both sides by IS1096; concurrently, a single IS1096 element and its flank were deleted. This study demonstrates that insertion sequence (IS) expansion and IS-induced rearrangements such as duplication, deletion and shuffling are major forces driving genomic diversity and evolution.