A SAS-6-Like Protein Suggests that the Toxoplasma Conoid Complex Evolved from Flagellar Components

SAS-6 is required for centriole biogenesis in diverse eukaryotes. Here, we describe a novel family of SAS-6-like (SAS6L) proteins that share an N-terminal domain with SAS-6 but lack coiled-coil tails. SAS6L proteins are found in a subset of eukaryotes that contain SAS-6, including diverse protozoa and green algae. In the apicomplexan parasite Toxoplasma gondii, SAS-6 localizes to the centriole but SAS6L is found above the conoid, an enigmatic tubulin-containing structure found at the apex of a subset of alveolate organisms. Loss of SAS6L causes reduced fitness in Toxoplasma. The Trypanosoma brucei homolog of SAS6L localizes to the basal-plate region, the site in the axoneme where the central-pair microtubules are nucleated. When endogenous SAS6L is overexpressed in Toxoplasma tachyzoites or Trypanosoma trypomastigotes, it forms prominent filaments that extend through the cell cytoplasm, indicating that it retains a capacity to form higher-order structures despite lacking a coiled-coil domain. We conclude that although SAS6L proteins share a conserved domain with SAS-6, they are a functionally distinct family that predates the last common ancestor of eukaryotes. Moreover, the distinct localization of the SAS6L protein in Trypanosoma and Toxoplasma adds weight to the hypothesis that the conoid complex evolved from flagellar components.     

Systematics of Old World Odontacolus Kieffer s.l. (Hymenoptera,Platygastridae s.l.): parasitoids?of?spider?eggs

The genera Odontacolus Kieffer and Cyphacolus Priesner are among the most distinctive platygastroid wasps because of their laterally compressed metasomal horn; however, their generic status has remained unclear. We present a morphological phylogenetic analysis comprising all 38 Old World and four Neotropical Odontacolus species and 13 Cyphacolus species, which demonstrates that the latter is monophyletic but nested within a somewhat poorly resolved Odontacolus. Based on these results Cyphacolus syn. n. is placed as a junior synonym of Odontacolus which is here redefined. The taxonomy of Old World Odontacolus s.str. is revised; the previously known species Odontacolus longiceps Kieffer (Seychelles), Odontacolus markadicus Veenakumari (India), Odontacolus spinosus (Dodd) (Australia) and Odontacolus hackeri (Dodd) (Australia) are re-described, and 32 new species are described: Odontacolus africanus Valerio & Austin sp. n. (Congo, Guinea, Kenya, Madagascar, Mozambique, South Africa, Uganda, Zimbabwe), Odontacolus aldrovandii Valerio & Austin sp. n. (Nepal), Odontacolus anningae Valerio & Austin sp. n. (Cameroon), Odontacolus australiensis Valerio & Austin sp. n. (Australia), Odontacolus baeri Valerio & Austin sp. n. (Australia), Odontacolus berryae Valerio & Austin sp. n. (Australia, New Zealand, Norfolk Island), Odontacolus bosei Valerio & Austin sp. n. (India, Malaysia, Sri Lanka), Odontacolus cardaleae Valerio & Austin sp. n. (Australia), Odontacolus darwini Valerio & Austin sp. n. (Thailand), Odontacolus dayi Valerio & Austin sp. n. (Indonesia), Odontacolus gallowayi Valerio & Austin sp. n. (Australia), Odontacolus gentingensis Valerio & Austin sp. n. (Malaysia), Odontacolus guineensis Valerio & Austin sp. n. (Guinea), Odontacolus harveyi Valerio & Austin sp. n. (Australia), Odontacolus heratyi Valerio & Austin sp. n. (Fiji), Odontacolus heydoni Valerio & Austin sp. n. (Malaysia, Thailand), Odontacolus irwini Valerio & Austin sp. n. (Fiji), Odontacolus jacksonae Valerio & Austin sp. n. (Cameroon, Guinea, Madagascar), Odontacolus kiau Valerio & Austin sp. n. (Papua New Guinea), Odontacolus lamarcki Valerio & Austin sp. n. (Thailand), Odontacolus madagascarensis Valerio & Austin sp. n. (Madagascar), Odontacolus mayri Valerio & Austin sp. n. (Indonesia, Thailand), Odontacolus mot Valerio & Austin sp. n. (India), Odontacolus noyesi Valerio & Austin sp. n. (India, Indonesia), Odontacolus pintoi Valerio & Austin sp. n. (Australia, New Zealand, Norfolk Island), Odontacolus schlingeri Valerio & Austin sp. n. (Fiji), Odontacolus sharkeyi Valerio & Austin sp. n. (Thailand), Odontacolus veroae Valerio & Austin sp. n. (Fiji), Odontacolus wallacei Valerio & Austin sp. n. (Australia, Indonesia, Malawi, Papua New Guinea), Odontacolus whitfieldi Valerio & Austin sp. n. (China, India, Indonesia, Sulawesi, Malaysia, Thailand, Vietnam), Odontacolus zborowskii Valerio & Austin sp. n. (Australia), and Odontacolus zimi Valerio & Austin sp. n. (Madagascar). In addition, all species of Cyphacolus are here transferred to Odontacolus: Odontacolus asheri (Valerio, Masner & Austin) comb. n. (Sri Lanka), Odontacolus axfordi (Valerio, Masner & Austin) comb. n. (Australia), Odontacolus bhowaliensis (Mani & Mukerjee) comb. n. (India), Odontacolus bouceki (Austin & Iqbal) comb. n. (Australia), Odontacolus copelandi (Valerio, Masner & Austin) comb. n. (Kenya, Nigeria, Zimbabwe, Thailand), Odontacolus diazae (Valerio, Masner & Austin) comb. n. (Kenya), Odontacolus harteni (Valerio, Masner & Austin) comb. n. (Yemen, Ivory Coast, Paskistan), Odontacolus jenningsi (Valerio, Masner & Austin) comb. n. (Australia), Odontacolus leblanci (Valerio, Masner & Austin) comb. n. (Guinea), Odontacolus lucianae (Valerio, Masner & Austin) comb. n. (Ivory Coast, Madagascar, South Africa, Swaziland, Zimbabwe), Odontacolus normani (Valerio, Masner & Austin) comb. n. (India, United Arab Emirates), Odontacolus sallyae (Valerio, Masner & Austin) comb. n. (Australia), Odontacolus tessae (Valerio, Masner & Austin) comb. n. (Australia), Odontacolus tullyae (Valerio, Masner & Austin) comb. n. (Australia), Odontacolus veniprivus (Priesner) comb. n. (Egypt), and Odontacolus watshami (Valerio, Masner & Austin) comb. n. (Africa, Madagascar). Two species of Odontacolus are transferred to the genus Idris Förster: Idris longispinosus (Girault) comb. n. and Idris amoenus (Kononova) comb. n., and Odontacolus doddi Austin syn. n. is placed as a junior synonym of Odontacolus spinosus (Dodd). Odontacolus markadicus, previously only known from India, is here recorded from Brunei, Malaysia, Sri Lanka, Thailand and Vietnam. The relationships, distribution and biology of Odontacolus are discussed, and a key is provided to identify all species.     

Grassland area determines beetle assemblage dissimilarity from surrounding floodplain forest

Patch size is known to affect biodiversity in fragmented landscapes, but is usually examined in systems where the surrounding matrix habitat is unfavourable. We examined beetle diversity in a floodplain ecosystem that is characterised by naturally occurring grassland patches within a dominant matrix of contrasting yet habitable forest. We asked whether differences in the beetle assemblage between grassland and forest vegetation depended on the area of the grassland patch, which is a function of its flooding frequency and duration: smaller grasslands tend to be higher on the floodplain and are flooded less often and for shorter periods than larger grasslands. We found a negative relationship between grassland area and beetle abundance and species richness, and a positive relationship between grassland area and compositional dissimilarity from the surrounding forest. As expected, we found an overall difference in composition between forest and grassland assemblages, with five beetle species more common in the grasslands. Our study indicates that floodplain grasslands not only support beetle assemblages that are distinct from the surrounding forest, but that assemblages from the larger grasslands are compositionally more distinct than those from smaller grasslands. A likely cause of this pattern is the reduced edge effects and greater environmental contrast between forest and large grasslands that may be exposed to greater variation in local climate. Ongoing changes to flood regimes and potential encroachment of forest plants may decrease grassland area in the future, which may reduce spatial heterogeneity in the insect community in this unique floodplain ecosystem.     

The spatial scaling of beta diversity

Beta diversity is an important concept used to describe turnover in species composition across a wide range of spatial and temporal scales, and it underpins much of conservation theory and practice. Although substantial progress has been made in the mathematical and terminological treatment of different measures of beta diversity, there has been little conceptual synthesis of potential scale dependence of beta diversity with increasing spatial grain and geographic extent of sampling. Here, we evaluate different conceptual approaches to the spatial scaling of beta diversity, interpreted from ‘fixed’ and ‘varying’ perspectives of spatial grain and extent. We argue that a ‘sliding window’ perspective, in which spatial grain and extent covary, is an informative way to conceptualize community differentiation across scales. This concept more realistically reflects the varying empirical approaches that researchers adopt in field sampling and the varying scales of landscape perception by different organisms. Scale dependence in beta diversity has broad implications for emerging fields in ecology and biogeography, such as the integration of fine‐resolution ecogenomic data with large‐scale macroecological studies, as well as for guiding appropriate management responses to threats to biodiversity operating at different spatial scales.     

Modelling Coral Reef Futures to Inform Management: Can Reducing Local-Scale Stressors Conserve Reefs under Climate Change?

Climate change has emerged as a principal threat to coral reefs, and is expected to exacerbate coral reef degradation caused by more localised stressors. Management of local stressors is widely advocated to bolster coral reef resilience, but the extent to which management of local stressors might affect future trajectories of reef state remains unclear. This is in part because of limited understanding of the cumulative impact of multiple stressors. Models are ideal tools to aid understanding of future reef state under alternative management and climatic scenarios, but to date few have been sufficiently developed to be useful as decision support tools for local management of coral reefs subject to multiple stressors. We used a simulation model of coral reefs to investigate the extent to which the management of local stressors (namely poor water quality and fishing) might influence future reef state under varying climatic scenarios relating to coral bleaching. We parameterised the model for Bolinao, the Philippines, and explored how simulation modelling can be used to provide decision support for local management. We found that management of water quality, and to a lesser extent fishing, can have a significant impact on future reef state, including coral recovery following bleaching-induced mortality. The stressors we examined interacted antagonistically to affect reef state, highlighting the importance of considering the combined impact of multiple stressors rather than considering them individually. Further, by providing explicit guidance for management of Bolinao''s reef system, such as which course of management action will most likely to be effective over what time scales and at which sites, we demonstrated the utility of simulation models for supporting management. Aside from providing explicit guidance for management of Bolinao''s reef system, our study offers insights which could inform reef management more broadly, as well as general understanding of reef systems.     

Localized Hotspots Drive Continental Geography of Abnormal Amphibians on U.S. Wildlife Refuges

Amphibians with missing, misshapen, and extra limbs have garnered public and scientific attention for two decades, yet the extent of the phenomenon remains poorly understood. Despite progress in identifying the causes of abnormalities in some regions, a lack of knowledge about their broader spatial distribution and temporal dynamics has hindered efforts to understand their implications for amphibian population declines and environmental quality. To address this data gap, we conducted a nationwide, 10-year assessment of 62,947 amphibians on U.S. National Wildlife Refuges. Analysis of a core dataset of 48,081 individuals revealed that consistent with expected background frequencies, an average of 2% were abnormal, but abnormalities exhibited marked spatial variation with a maximum prevalence of 40%. Variance partitioning analysis demonstrated that factors associated with space (rather than species or year sampled) captured 97% of the variation in abnormalities, and the amount of partitioned variance decreased with increasing spatial scale (from site to refuge to region). Consistent with this, abnormalities occurred in local to regional hotspots, clustering at scales of tens to hundreds of kilometers. We detected such hotspot clusters of high-abnormality sites in the Mississippi River Valley, California, and Alaska. Abnormality frequency was more variable within than outside of hotspot clusters. This is consistent with dynamic phenomena such as disturbance or natural enemies (pathogens or predators), whereas similarity of abnormality frequencies at scales of tens to hundreds of kilometers suggests involvement of factors that are spatially consistent at a regional scale. Our characterization of the spatial and temporal variation inherent in continent-wide amphibian abnormalities demonstrates the disproportionate contribution of local factors in predicting hotspots, and the episodic nature of their occurrence.     

Lymphocytes and Macrophages Are Infected by Theileria equi,but T Cells and B Cells Are Not Required to Establish Infection In Vivo

Theileria equi has a biphasic life cycle in horses, with a period of intraleukocyte development followed by patent erythrocytic parasitemia that causes acute and sometimes fatal hemolytic disease. Unlike Theileria spp. that infect cattle (Theileria parva and Theileria annulata), the intraleukocyte stage (schizont) of Theileria equi does not cause uncontrolled host cell proliferation or other significant pathology. Nevertheless, schizont-infected leukocytes are of interest because of their potential to alter host cell function and because immune responses directed against this stage could halt infection and prevent disease. Based on cellular morphology, Theileria equi has been reported to infect lymphocytes in vivo and in vitro, but the specific phenotype of schizont-infected cells has yet to be defined. To resolve this knowledge gap in Theileria equi pathogenesis, peripheral blood mononuclear cells were infected in vitro and the phenotype of infected cells determined using flow cytometry and immunofluorescence microscopy. These experiments demonstrated that the host cell range of Theileria equi was broader than initially reported and included B lymphocytes, T lymphocytes and monocyte/macrophages. To determine if B and T lymphocytes were required to establish infection in vivo, horses affected with severe combined immunodeficiency (SCID), which lack functional B and T lymphocytes, were inoculated with Theileria equi sporozoites. SCID horses developed patent erythrocytic parasitemia, indicating that B and T lymphocytes are not necessary to complete the Theileria equi life cycle in vivo. These findings suggest that the factors mediating Theileria equi leukocyte invasion and intracytoplasmic differentiation are common to several leukocyte subsets and are less restricted than for Theileria annulata and Theileria parva. These data will greatly facilitate future investigation into the relationships between Theileria equi leukocyte tropism and pathogenesis, breed susceptibility, and strain virulence.     

Monocytes Loaded with Indocyanine Green as Active Homing Contrast Agents?Permit Optical Differentiation of Infectious and Non-Infectious Inflammation

Distinguishing cutaneous infection from sterile inflammation is a diagnostic challenge and currently relies upon subjective interpretation of clinical parameters, microbiological data, and nonspecific imaging. Assessing characteristic variations in leukocytic infiltration may provide more specific information. In this study, we demonstrate that homing of systemically administered monocytes tagged using indocyanine green (ICG), an FDA-approved near infrared dye, may be assessed non-invasively using clinically-applicable laser angiography systems to investigate cutaneous inflammatory processes. RAW 264.7 mouse monocytes co-incubated with ICG fluoresce brightly in the near infrared range. In vitro, the loaded cells retained the ability to chemotax toward monocyte chemotactic protein-1. Following intravascular injection of loaded cells into BALB/c mice with induced sterile inflammation (Complete Freund’s Adjuvant inoculation) or infection (Group A Streptococcus inoculation) of the hind limb, non-invasive whole animal imaging revealed local fluorescence at the inoculation site. There was significantly higher fluorescence of the inoculation site in the infection model than in the inflammation model as early as 2 hours after injection (p<0.05). Microscopic examination of bacterial inoculation site tissue revealed points of near infrared fluorescence, suggesting the presence of ICG-loaded cells. Development of a non-invasive technique to rapidly image inflammatory states without radiation may lead to new tools to distinguish infectious conditions from sterile inflammatory conditions at the bedside.     

Characterization of a New Chronic Lymphocytic Leukemia Cell Line for Mechanistic In Vitro and In Vivo Studies Relevant to Disease

Studies of chronic lymphocytic leukemia (CLL) have yielded substantial progress, however a lack of immortalized cell lines representative of the primary disease has hampered a full understanding of disease pathogenesis and development of new treatments. Here we describe a novel CLL cell line (OSU-CLL) generated by EBV transformation, which displays a similar cytogenetic and immunophenotype observed in the patient’s CLL (CD5 positive with trisomy 12 and 19). A companion cell line was also generated from the same patient (OSU-NB). This cell line lacked typical CLL characteristics, and is likely derived from the patient’s normal B cells. In vitro migration assays demonstrated that OSU-CLL exhibits migratory properties similar to primary CLL cells whereas OSU-NB has significantly reduced ability to migrate spontaneously or towards chemokine. Microarray analysis demonstrated distinct gene expression patterns in the two cell lines, including genes on chromosomes 12 and 19, which is consistent with the cytogenetic profile in this cell line. Finally, OSU-CLL was readily transplantable into NOG mice, producing uniform engraftment by three weeks with leukemic cells detectable in the peripheral blood spleen and bone marrow. These studies describe a new CLL cell line that extends currently available models to study gene function in this disease.