Blood parameters and parasite burden in cattle with chronic fascioliasis.

Fascioliasis is a trematodiasis that affects domestic and wild animals as well as humans worldwide. It is a well-recognized disease in livestock, were it produces serious economic losses. Yet in cattle, there is limited information about the burden of liver flukes and its relation to the eggs per gram shed to the environment. There is also lack of knowledge on the effect of parasite load in blood parameters of infected animals, which is important to evaluate the severity and progression of the disease. The objective of this work was to gain insight in these aspects. Cattle from Mendoza province, Argentina, were inspected at a farm and at the abattoir determining the presence or absence of Fasciola hepatica. Each animal was sampled for blood and feces and in the slaughterhouse the livers were inspected. Hematology and blood chemistry parameters were determined, feces were examined for F. hepatica eggs by a quantitative sedimentation technique and livers were thoroughly inspected to determine the number of flukes. Infected cattle presented a mild burden of liver flukes per animal, strongly correlated (r = 0.72) to the number of eggs per gram of feces. The total number of eggs (X̄=35,100) shed per animal to the environment and the type of livestock management techniques in the region exacerbate the role of cattle as efficient reservoirs of this disease. Statistically significant lower red blood cell, lymphocyte and neutrophil counts were observed in infected compared to uninfected animals. All hepatic parameters tested showed highly statistically significant differences (p < 0.001) as well as proteins by cause of rise of globulins in infected cattle. The correlation between the amount of flukes in the liver and the number of eggs per gram of faces indicates coprology as a reliable and cost-effective method to infer parasite burden. The impact of fascioliasis on blood parameters can be of aid for the veterinary practitioner on the assessment of this disease on cattle.

Plasmid-mediated fosfomycin resistance in Escherichia coli isolates of worldwide origin.

OBJECTIVES: Fosfomycin is a first-line treatment for uncomplicated urinary tract infections (UTIs) in several European countries, and it is increasingly becoming the treatment of choice globally. Resistance to fosfomycin in Escherichia coli can be exerted through several mechanisms, including the acquisition of fosfomycin-modifying enzymes, of which the FosA-type enzymes are the most common. This study analysed, both phenotypically and genotypically, an international collection of E. coli strains harbouring acquired fosA genes. METHODS: Thirty-one fosA-positive E. coli isolates were obtained from both clinical and environmental sources, from seven countries (Portugal (n = 12), Switzerland (n = 9), China (n = 3), France (n = 2), Nepal (n = 2), South Africa (n = 2), Kuwait (n = 1)). MICs were determined according to EUCAST guidelines. Whole genome sequencing (WGS) was performed on 23 isolates, and complete fosA plasmid sequences were determined for 12. Conjugation assays were performed on seven isolates. RESULTS: All isolates exhibited high-level resistance to fosfomycin (64 to >256 mg/L). WGS of 23 isolates identified 17 sequence types (STs), and 16 harboured fosA3, four fosA4, two fosA8, and one fosA10. ESBLs, pAmpC, or carbapenemase genes were present in 15, four, and three isolates, respectively. The fosA plasmids of 12 isolates were determined and were diverse in size (∼67 kb to ∼235 kb), resistance gene carriage, and replicon types. Six fosA plasmids additionally carried ESBL or carbapenemase genes. Conjugation assays, performed on seven isolates harbouring diverse plasmids, identified that all were capable of being transmitted. CONCLUSION: This study highlights the necessity of the surveillance and close monitoring of fosfomycin resistance in E. coli, essential to maintain the optimal use of this treatment option.

Ozone Environmental Pollution: Relationship between the Intestine and Neurodegenerative Diseases.

Repeated exposure to environmental ozone causes a chronic state of oxidative stress. This state is present in chronic degenerative diseases and induces a loss of control of the inflammatory response. Redox system dysfunction and failures in control of inflammatory responses are involved in a vicious circle that maintains and increases the degenerative process. The intestine also responds to secondary reactive species formed by exposure to ozone doses, generating noxious stimuli that increase degenerative damage. This review aims to elucidate how environmental pollution, mainly by ozone, induces a state of chronic oxidative stress with the loss of regulation of the inflammatory response, both in the intestine and in the brain, where the functionality of both structures is altered and plays a determining role in some neurodegenerative and chronic degenerative diseases. For this purpose, we searched for information on sites such as the Cochrane Library Database, PubMed, Scopus, and Medscape. Reviewing the data published, we can conclude that environmental pollutants are a severe health problem. Ozone pollution has different pathways of action, both molecular and systemic, and participates in neurodegenerative diseases such as Parkinson's and Alzheimer's disease as well in bowel diseases as Inflammatory Bowel Disease, Crohn's Disease, and Irritable Bowel Syndrome.

Antibiotic heteroresistance in ESKAPE pathogens, from bench to bedside.

BACKGROUND: Heteroresistance refers to subpopulation-mediated differential antimicrobial susceptibility within a clonal bacterial population. Usually, it designates a resistant subpopulation identified within an isolate considered susceptible by classical antimicrobial susceptibility testing. Heteroresistance lacks a uniform microbiological definition for diagnostic laboratories, and its clinical impact remains unclear for most bacterial species. OBJECTIVES: This narrative review aims to provide a practical overview on the latest developments in the field of heteroresistance for both clinical microbiologists and physicians, with a particular focus on ESKAPE pathogens. SOURCES: A literature search was performed on Pubmed and Google with the key words heteroresistance (heterogeneity OR heterogeneous) AND antibiotic resistance. Among the 836 publications selected based on their abstracts, the most relevant for the detection, epidemiology and clinical impact of heteroresistance in ESKAPE pathogens are discussed here. CONTENT: Heteroresistance is only clearly defined for heterogeneous vancomycin intermediate Staphylococcus aureus. We compiled a larger microbiological definition to be applicable to other bacterial species and antibiotics in the clinical context. We highlighted the key technical points of population analysis profile, which is the reference standard for detecting heteroresistance. Heteroresistance to polymyxins, ß-lactams (carbapenems, cefiderocol), fosfomycin, tigecycline and aminoglycosides is frequently reported in multidrug-resistant gram-negative pathogens. Treatment failure due to heteroresistance has been described in case reports or retrospective studies, so far confirmed by meta-analyses in the case of heterogeneous vancomycin intermediate S. aureus only. Finally, to treat pandrug-resistant bacterial infections, the option of targeting susceptible subpopulations of resistant isolates using tailored antibiotic combinations is also discussed. IMPLICATIONS: Systematic heteroresistance screening by clinical laboratories is not currently recommended. Nevertheless, we should be aware of this phenomenon, and in specific cases, such as treatment failure, heteroresistance should be tested by reference laboratories. Additional studies using standardized methods are needed to improve our understanding of heteroresistance and further assess its clinical impact.

A Single Nucleotide Polymorphism Translates into a Radical Amino Acid Substitution at the Ligand-Binding Site in Fasciola hepatica Carboxylesterase B.

Fasciola hepatica anthelmintic resistance may be associated with the catalytic activity of xenobiotic metabolizing enzymes. The gene expression of one of these enzymes, identified as carboxylesterase B (CestB), was previously described as inducible in adult parasites under anthelmintic treatment and exhibited a single nucleotide polymorphism at position 643 that translates into a radical amino acid substitution at position 215 from Glutamic acid to Lysine. Alphafold 3D models of both allelic sequences exhibited a significant affinity pocket rearrangement and different ligand-docking modeling results. Further bioinformatics analysis confirmed that the radical amino acid substitution is located at the ligand affinity site of the enzyme, affecting its affinity to serine hydrolase inhibitors and preferences for ester ligands. A field genotyping survey from parasite samples obtained from two developmental stages isolated from different host species from Argentina and Mexico exhibited a 37% allele distribution for 215E and a 29% allele distribution for 215K as well as a 34% E/K heterozygous distribution. No linkage to host species or geographic origin was found in any of the allele variants.

Taxon-rich transcriptomics supports higher-level phylogeny and major evolutionary trends in Foraminifera.

Foraminifera, classified in the supergroup Rhizaria, are a common and highly diverse group of mainly marine protists. Despite their evolutionary and ecological importance, only limited genomic data (one partial genome and nine transcriptomic datasets) have been published for this group. Foraminiferal molecular phylogeny is largely based on 18S rRNA gene sequence analysis. However, due to highly variable evolutionary rates of substitution in ribosomal genes plus the existence of intragenomic variation at this locus, the relationships between and within foraminiferal classes remain uncertain. We analyze transcriptomic data from 28 species, adding 19 new species to the previously published dataset, including members of the strongly under-represented class Monothalamea. A phylogenomic reconstruction of Rhizaria, rooted with alveolates and stramenopiles, based on 199 genes and 68 species supports the monophyly of Foraminifera and their sister relationship to Polycystinea. The phylogenomic tree of Foraminifera is very similar to the 18S rRNA tree, with the paraphyletic single-chambered monothalamids giving rise to the multi-chambered Tubothalamea and Globothalamea. Within the Monothalamea, our analyses confirm the monophyly of the giant, deep-sea xenophyophores that branch within clade C and indicate the basal position of monothalamous clades D and E. The multi-chambered Globothalamea are monophyletic and comprise the paraphyletic Textulariida and monophyletic Rotaliida. Our phylogenomic analyses support major evolutionary trends of Foraminifera revealed by ribosomal phylogenies and reinforce their current higher-level classification.

Characterization of Amino Acid Substitution W20S in MgrB Involved in Polymyxin Resistance in Klebsiella pneumoniae.

In the major human pathogen Klebsiella pneumoniae, MgrB inactivation by disruptive insertion sequence (IS) elements and mutations leading to early termination are known to play an important role in polymyxin resistance. In this study, we examined a collection of invasive blaKPC-2-producing K. pneumoniae isolates belonging to the high-risk clone sequence type 258 (ST258) displaying high rates of resistance to many antimicrobials, including polymyxins. We identified a deleterious substitution (W20S) in MgrB and confirmed by genetic complementation analysis that this variant was inactive, leading to increased polymyxin B and colistin MICs. IMPORTANCE Carbapenem-resistant Gram-negative bacteria are designated critical pathogens by the World Health Organization. Polymyxins (i.e., polymyxin B and colistin) are last-resort antibiotics and particularly useful against these multidrug-resistant bacteria. In Klebsiella pneumoniae, the inactivation of MgrB, a negative regulator of PhoPQ, was shown to be the major pathway leading to colistin resistance. While gene disruption by insertion sequence (IS) elements and mutations leading to early termination (stop codons) are frequent, deleterious mutations are not observed frequently and have not been characterized. Here, we identified a deleterious substitution (W20S) in MgrB among a collection of bloodstream infection, blaKPC-2-producing K. pneumoniae sequence type 258 (ST258) isolates, displaying high rates of resistance to polymyxins and associated with a high mortality rate. The dissemination of such a MgrB-W20S mutation leading to polymyxin resistance within the ST258 high-risk clone background is problematic and thus warrants particular attention.

Detección de casos de infección crónica, asintomática por trypanosoma cruzi en estudiantes que ingresen a una universidad pública nacional / etection of chronic asymptomatic infection cases due to trypanosoma cruzi in incoming students of a public national university

INTRODUCCIÓN La OMS define al Chagas como una enfermedad desatendida y endémica en Latinoamérica, donde viven alrededor de 70 millones de personas en riesgo de contraer la infección, y estima que un 95 % de las personas infectadas desconocen su estado y, por ende, no han recibido tratamiento. En la provincia de Mendoza, la prevalencia estimada de infección por Trypanosoma cruzi en personas gestantes está entre el 2 % y el 40 % según la zona geográfica. OBJETIVOS Conocer la prevalencia de casos crónicos asintomáticos de infección por Trypanosoma cruzi, factibles de ser tratados, en ingresantes a la universidad pública de la provincia de Mendoza. El perfil de ingresantes está compuesto mayormente por mujeres y personas con capacidad de gestar de 21 años o menores. MÉTODOS Se realizó un estudio descriptivo cuantitativo transversal. Se utilizaron las técnicas de hemaglutinación indirecta y enzimoinmunoanálisis. Los casos discordantes fueron derivados para su confirmación al Departamento de Enfermedades Zoonóticas y Vectoriales del Ministerio de Salud de Mendoza. RESULTADOS Se estudió a 202 de un total de 371 (55 %) estudiantes del primer año de la Facultad de Ciencias Médicas de la Universidad Nacional de Cuyo (Medicina 143, Tecnicaturas 122, Enfermería 106). Se detectaron 2 casos crónicos asintomáticos en estudiantes mujeres en edad fértil, que accedieron al seguimiento médico y tratamiento etiológico de la infección. DISCUSIÓN Los datos obtenidos permitieron a las autoridades sanitarias provinciales decidir respecto de la necesidad de ampliar la búsqueda de casos de infección crónica asintomática por T. cruzi en este grupo poblacional. Se logró constituir una unidad de diagnóstico y tratamiento para la enfermedad de Chagas y así, a partir de 2024, recibir los insumos necesarios para realizar el diagnóstico y seguimiento de la patología.

Epidemiological link between canine monocytic ehrlichiosis caused by Ehrlichia canis and the presence of Rhipicephalus sanguineus sensu stricto in Argentina.

In this work, we analyze data that support an epidemiological link between cases of canine monocytic ehrlichiosis (CME) by Ehrlichia canis and the presence of Rhipicephalus sanguineus sensu stricto as vector in an endemic area for this tick in Argentina. In a blood sample of a 1-year-old toy poodle with CME compatible clinical signs, which showed CME typical morulae in monocytes in Giemsa-stained blood smear, DNA of E. canis was detected by PCR. Further, DNA of E. canis was also detected in a female of R. sanguineus s.s. collected on the infected dog. Rhipicephalus sanguineus s.s. is the only member of the R. sanguineus group that prevails in the study area. The results of this study suggest that R. sanguineus s.s. may play a more important role in the transmission of E. canis than it was assumed so far. The epidemiological link between CME cases and R. sanguineus s.s. as vector in temperate areas of Argentina described in this work contrast previous studies which found that R. sanguineus sensu lato "tropical lineage" (which is absent in the study area) is competent to transmit E. canis but not R. sanguineus s.s.

Vertical and horizontal dissemination of an IncC plasmid harbouring rmtB 16S rRNA methylase gene, conferring resistance to plazomicin, among invasive ST258 and ST16 KPC-producing Klebsiella pneumoniae.

OBJECTIVES: Carbapenem resistance in Klebsiella pneumoniae is a major clinical challenge. Aminoglycosides remain an important asset in the current therapeutic arsenal to treat these infections. We examined aminoglycoside resistance phenotypes and genomics in a collection of 100 invasive KPC-producing K. pneumoniae isolates sequentially collected in a Brazilian tertiary hospital between 2014 and 2016. METHODS: Aminoglycoside susceptibility testing was performed. We used a combined long-read (MinION) and short-read (Illumina) whole-genome sequencing strategy to provide a genomic picture of aminoglycoside resistance genes, with particular emphasis on 16S rRNA methyltransferases and related plasmids. RESULTS: 68% of the strains were resistant to gentamicin and 42% to amikacin, with 35% resistant to both of these commonly used aminoglycosides. We identified the 16S rRNA methyltransferase gene rmtB in 30% of these isolates: 97% (29/30) belonged to sequence type 258 (ST258) and a single isolate to the emergent ST16 clone. In ST258 and ST16 the rmtB gene was located on large IncC plasmids of 177 kb and 174 kb, respectively, highly similar to a plasmid previously identified in Proteus mirabilis in the same hospital. Moreover, 99% of the isolates remained susceptible to the veterinary-approved drug apramycin, currently under clinical development for human medicine. CONCLUSION: Such findings in geographically and temporally related isolates suggest a combination of vertical clonal spread as well as horizontal interspecies and intraspecies plasmid transfer. This broad rmtB dissemination in an endemic setting for KPC-producing clones is worrisome since it provides resistance to most clinically available aminoglycosides, including the novel aminoglycoside-modifying enzyme-resistant plazomicin.

Insights into the global effect on Staphylococcus aureus growth arrest by induction of the endoribonuclease MazF toxin.

A crucial bacterial strategy to avoid killing by antibiotics is to enter a growth arrested state, yet the molecular mechanisms behind this process remain elusive. The conditional overexpression of mazF, the endoribonuclease toxin of the MazEF toxin-antitoxin system in Staphylococcus aureus, is one approach to induce bacterial growth arrest, but its targets remain largely unknown. We used overexpression of mazF and high-throughput sequence analysis following the exact mapping of non-phosphorylated transcriptome ends (nEMOTE) technique to reveal in vivo toxin cleavage sites on a global scale. We obtained a catalogue of MazF cleavage sites and unearthed an extended MazF cleavage specificity that goes beyond the previously reported one. We correlated transcript cleavage and abundance in a global transcriptomic profiling during mazF overexpression. We observed that MazF affects RNA molecules involved in ribosome biogenesis, cell wall synthesis, cell division and RNA turnover and thus deliver a plausible explanation for how mazF overexpression induces stasis. We hypothesize that autoregulation of MazF occurs by directly modulating the MazEF operon, such as the rsbUVW genes that regulate the sigma factor SigB, including an observed cleavage site on the MazF mRNA that would ultimately play a role in entry and exit from bacterial stasis.

Thermosensitive PBP2a requires extracellular folding factors PrsA and HtrA1 for Staphylococcus aureus MRSA ß-lactam resistance.

Staphylococcus aureus is a major human pathogen and represents a clinical challenge because of widespread antibiotic resistance. Methicillin resistant Staphylococcus aureus (MRSA) is particularly problematic and originates by the horizontal acquisition of mecA encoding PBP2a, an extracellular membrane anchored transpeptidase, which confers resistance to ß-lactam antibiotics by allosteric gating of its active site channel. Herein, we show that dual disruption of PrsA, a lipoprotein chaperone displaying anti-aggregation activity, together with HtrA1, a membrane anchored chaperone/serine protease, resulted in severe and synergistic attenuation of PBP2a folding that restores sensitivity to ß-lactams such as oxacillin. Purified PBP2a has a pronounced unfolding transition initiating at physiological temperatures that leads to irreversible precipitation and complete loss of activity. The concordance of genetic and biochemical data highlights the necessity for extracellular protein folding factors governing MRSA ß-lactam resistance. Targeting the PBP2a folding pathway represents a particularly attractive adjuvant strategy to combat antibiotic resistance.

Mortalidad en pacientes con enfermedad renal. Instituto de Nefrología. 2016 y 2017 / Mortality in patients with kidney disease. Institute of Nephrology, 2016 and 2017

Introducción: La Enfermedad Renal Crónica es un problema de salud mundial. Objetivo: Determinar el comportamiento de la mortalidad en pacientes con enfermedad renal en el Instituto de Nefrología durante 2016 y 2017. Material y Métodos: Estudio observacional descriptivo transversal de pacientes fallecidos con necropsia realizada. Se registraron variables demográficas, de laboratorio, las relacionadas con la terapia de reemplazo de la función renal y con el diagnóstico anatomo-patológico. Para cada una de las variables se calcularon frecuencias absolutas y relativas. En el caso de la variable presencia de sepsis en las defunciones, fue empleada la prueba de chi-cuadrado para la bondad del ajuste, para probar la hipótesis nula H0: de igualdad de la distribución de las tres categorías de la variable. Resultados: Se estudiaron 48 fallecidos con necropsia, 48,9 por ciento del total de fallecidos en el periodo. La correspondencia clínico patológica fue 80,1 por ciento. Predominó el sexo masculino, el grupo de edad superior a 60 años y la hipertensión arterial como antecedente. El método de terapia de reemplazo renal más documentado fue la hemodiálisis, mediante catéter venoso central un 87,8 por ciento. El 61,8 por ciento de los fallecidos recibieron tratamiento hemodialítico por 3 meses o menos. La sepsis fue la segunda causa de muerte precedida por eventos cardio y cerebrovasculares; no obstante, en el análisis de la totalidad de necropsias, la infección asociada directa o indirecta a la muerte tuvo una frecuencia mayor. Conclusiones: La infección directa o indirectamente asociada a la muerte, la hipoalbuminemia y el acceso vascular mediante catéter se relacionan con la mortalidad en el periodo(AU)

Introduction: Chronic kidney disease is a health problem worldwide. Objective: To determine the behavior of mortality in patients with kidney damage in the Nephrology Institute during the years between 2016 and 2017. Material and Method: A cross-sectional descriptive observational study was conducted in 48 deceased patients who underwent necropsy. Demographic and laboratory variables were recorded, as well as those related to the type of renal function replacement therapy and the anatomopathological diagnosis. Absolute and relative frequencies were calculated for each of the variables. In the case of the variable presence of sepsis in deaths, the Chi-Square Goodness-of-Fit Test was used to test the Null Hypothesis HO: uniformity of the distribution of the three categories of the variable. Results: A total of 48 deceased were studied at necropsy, representing 48.9 percent of the total number of deaths within the period. The clinical- pathological correlation was 80.1percent. The male sex, the group over the age of 60 years, and arterial hypertension as antecedent of the disease predominated in the study. The most documented method of renal function replacement therapy was hemodialysis which was performed through central venous catheter, 87.8 percent. The 61.8 percent of deceased patients received hemodialysis treatment for 3 months or less. Sepsis represented the second cause of death preceded by cardiovascular and cerebrovascular events. However, during the analysis of all the necropsies, the direct or indirect infection associated with the death had a greater frequency. Conclusions: Direct or indirect infections associated with death, hypoalbuminemia, and the vascular access with venous catheter was related to mortality during the observed period(AU)

Antidepressant-like effect of Casimiroa pubescens root extracts.

In this study, we investigated the antidepressant-like effects of the hexane (HCP), ethyl acetate (ECP) and methanol (MCP) extracts of the roots of Casimiroa pubescens Ramírez (Rutaceae) using the forced swim test (FST). In an initial experiment, each extract was orally administered to mice only once 60 min before to the FST. In a second experiment, doses were administered 24, 7 and 1 h before testing. Our results showed that the triple administration of the extracts provided a stronger effect than single administration. However, the combination of HCP at 7.5 mg/kg and imipramine (IMI) at 12.5 mg/kg showed the greatest effect. The coumarins 3-(1',1', dimethyl allyl)-herniarin, auraptene, 8-geranyl-oxy psoralen, isopimpinellin and the flavonoid zapotin were isolated from the extracts. The hexane extract of C. pubescens showed an antidepressant-like activity, which may inspire further studies on developing new antidepressant agents.

Air Sac Nematode ( Serratospiculum tendo) Infection in an Austral Peregrine Falcon ( Falco peregrinus cassini) in Argentina.

We report a case of air sac nematode ( Serratospiculum tendo) infection in an adult male Austral Peregrine Falcon ( Falco peregrinus cassini) admitted to a rehabilitation center in Mendoza Province, Argentina, in September 2017. This case of air sac nematodes reported in an Argentine raptor is only the second report of S. tendo in South America. We recommend examination of all raptors, especially those falcon species that include insects in their diet and inhabit open lands and those in rehabilitation centers or kept for falconry, education, or captive breeding. Fecal analysis and microscopic examination of oral swabs for evidence of parasites are simple noninvasive diagnostic procedures that allow easy detection of these parasites under field and captive circumstances.

Linking toxin-antitoxin systems with phenotypes: A Staphylococcus aureus viewpoint.

Toxin-antitoxin systems (TAS) are genetic modules controlling different aspects of bacterial physiology. They operate with versatility in an incredibly wide range of mechanisms. New TA modules with unexpected functions are continuously emerging from genome sequencing projects. Their discovery and functional studies have shed light on different characteristics of bacterial metabolism that are now applied to understanding clinically relevant questions and even proposed as antimicrobial treatment. Our main source of knowledge of TA systems derives from Gram-negative bacterial studies, but studies in Gram-positives are becoming more prevalent and provide new insights to TA functional mechanisms. In this review, we present an overview of the present knowledge of TA systems in the clinical pathogen Staphylococcus aureus, their implications in bacterial physiology and discuss relevant aspects that are driving TAS research. "This article is part of a Special Issue entitled: Dynamic gene expression, edited by Prof. Patrick Viollier".

Report of Amblyomma parvitarsum infesting goats in Midwestern Argentina.

Adult ticks were collected from goats on September 2012 in the locality of Trintrica (35° 17' 19″ S - 68° 44' 6″ W, 1430 m.a.s.l.), Mendoza, Argentina. The specimens were identified as seven females and three males of Amblyomma parvitarsum Neumann, 1901. This record represents the new occurrence of A. parvitarsum in the province of Mendoza, as well as the first report of the parasitism in goats along the geographical range of A. parvitarsum.

Reducing long-branch effects in multi-protein data uncovers a close relationship between Alveolata and Rhizaria.

Rhizaria is a major eukaryotic group of tremendous diversity, including amoebae with spectacular skeletons or tests (Radiolaria and Foraminifera), plasmodial parasites (Plasmodiophorida) and secondary endosymbionts (Chlorarachniophyta). Current phylogeny places Rhizaria in an unresolved trichotomy with Stramenopila and Alveolata (supergroup "SAR"). We assembled a 147-protein data set with extensive rhizarian coverage (M147), including the first transcriptomic data for a euglyphid amoeba. Phylogenetic pre-screening of individual proteins indicated potential problems with radically misplaced sequences due either to contamination of rhizarian sequences amplified from wild collected material and/or extremely long branches (xLBs). Therefore, two data subsets were extracted containing either all proteins consistently recovering rhizarian monophyly (M34) or excluding all proteins with ⩾3 xLBs (defined as ⩾2× the average terminal branch length for the tree). Phylogenetic analyses of M147 give conflicting results depending on the outgroup and method of analysis but strongly support an exclusive Rhizaria+Alveolata (R+A) clade with both data subsets (M34 and M37) regardless of phylogenetic method used. Support for an R+A clade is most consistent when a close outgroup is used and decreases with more distant outgroups, suggesting that support for alternative SAR topologies may reflect a long-branch attraction artifact. A survey of xLB distribution among taxa and protein functional category indicates that small "informational" proteins in particular have highly variable evolutionary rates with no consistent pattern among taxa.

Evolutionary Origins of Rhizarian Parasites.

The SAR group (Stramenopila, Alveolata, Rhizaria) is one of the largest clades in the tree of eukaryotes and includes a great number of parasitic lineages. Rhizarian parasites are obligate and have devastating effects on commercially important plants and animals but despite this fact, our knowledge of their biology and evolution is limited. Here, we present rhizarian transcriptomes from all major parasitic lineages in order to elucidate their evolutionary relationships using a phylogenomic approach. Our results suggest that Ascetosporea, parasites of marine invertebrates, are sister to the novel clade Apofilosa. The phytomyxean plant parasites branch sister to the vampyrellid algal ectoparasites in the novel clade Phytorhiza. They also show that Ascetosporea + Apofilosa + Retaria + Filosa + Phytorhiza form a monophyletic clade, although the branching pattern within this clade is difficult to resolve and appears to be model-dependent. Our study does not support the monophyly of the rhizarian parasitic lineages (Endomyxa), suggesting independent origins for rhizarian animal and plant parasites.