Sphingolipids in Toxoplasma gondii; synthesis and scavenging

Toxoplasma gondii is a globally endemic parasite which can cause severe illness in animal livestock and humans. Currently there are no effective drug treatments which do not have severe side effects and therefore the search for new drugs is of significant importance. Sphingolipids have been shown to be essential in many different eukaryotic cell types through their roles in cell signaling and regulatory roles in cell transport. Serine palmitoyltransferase is the first rate limiting step in biosynthesis and the inhibition of this enzyme has proved lethal in many organisms. This enzyme is currently uncharacterized in T.gondii and other Apicomplexa. In this work the evolutionary origins, function and the cellular localization of this protein were investigated. Further to this, endocytosis assays were also performed on extracellular tachyzoites to investigate the potential of the parasite to scavenge complex sphingolipids

Characterizing environmental, temporal and spatial scaling of Rhizosphere fungi in bioenergy crops : and their role in belowground carbon cycling

The rhizosphere consists of plant roots and the adjoining soil, which contains a functionally and genetically rich fungal community. The obligate plant symbionts, the mycorrhizal fungi, have been shown to receive substantial quantities of plant-derived C and play an important role in belowground C dynamics. The flux and residence time of C is however likely to be highly species-specific for rhizosphere fungi, and therefore their abundance and composition will likely have important implications on C storage belowground. Rhizosphere fungal community formation is extremely complex and despite being an area of intense research, current understanding is limited. The composition and abundance of rhizosphere fungi have been shown to vary with temporal and environmental parameters, and potentially geographical separation. However, no studies to date have analysed these parameters simultaneously to isolate the independent effects of each. Clone libraries in conjunction with TRFLP were performed before progressing to 454-pyrosequencing to profile the rhizosphere fungal community of a short rotation coppice (SRC) willow filed site. In this work, distinct seasonal fungal assemblages were shown, with N availability having a large effect in summer and geographical distance effects in autumn sampling points. Additionally, a rare large transition in the composition of the rhizosphere fungi was also demonstrated, which was most likely driven by extreme rainfall earlier in the growing season of the year of transition. Finally, using ₁₃C-labelled-CO₂ the belowground movement of recently derived photo-assimilates was shown to differ between Miscanthus x giganteus and SRC willow, however no significant fluxes were associated with rhizosphere fungal pathways in either crop. Results from this work demonstrate that some of the considerable complexity of microbial communities could have between overlooked in previous community analyses, whilst the flow of C within through mycorrhizal pathways maybe less important in bioenergy cropping systems compared to other ecosystems

Spatio-temporal variation of core and satellite arbuscular mycorrhizal fungus communities in Miscanthus giganteus

Arbuscular mycorrhizal fungi (AMF) are a group of obligate plant symbionts which can promote plant nutrition. AMF communities are diverse, but the factors which control their assembly in space and time remain unclear. In this study, the contributions of geographical distance, environmental heterogeneity and time in shaping AMF communities associated with Miscanthus giganteus (a perennial grass originating from south-east Asia) were determined over a 13 months period. In particular, the community was partitioned into core (abundant and persistent taxa) and satellite (taxa with low abundance and persistence) constituents and the drivers of community assembly for each determined. β-diversity was exceptionally low across the 140 m line transects, and there was limited evidence of geographical scaling effects on the composition of the core, satellite or combined communities. However, AMF richness and community composition changed over time associated with fluctuation within both the core and satellite communities. The degree to which AMF community variation was explained by soil properties was consistently higher in the core community than the combined and satellite communities, suggesting that the satellite community had considerable stochasticity associated with it. We suggest that the partitioning of communities into their core and satellite constituents could be employed to enhance the variation explained within microbial community analyses

Numerical Distribution of Lymphoid Nodules in the Human Sigmoid Colon, Rectosigmoidal Junction, Rectum, and Anal Canal

There is little information on the numerical distribution of lymphoid nodules (LN) in distal segments of the human large bowel. A novel approach was therefore developed to assess the number of LN in the sigmoid colon, the rectosigmoid segment, the rectum, and the anal canal in humans. The distal large bowel from five cadavers was selected for quantitative study. The number of LN was scored macroscopically from the proximal sigmoid colon to the distal anal canal. A numerical distribution, previously unreported, consisting of two circular bands of LN was observed in each of the five cadavers. One band was located 3 cm proximal from the pectinate line and the other was located at the rectosigmoid segment. Significantly more LN occurred 3–5 cm proximal to the pectinate line compared to areas distal or proximal to this band of LN. This band of LN has not been reported previously in humans

Unexpectedly high beta-diversity of root-associated fungal communities in the Bolivian Andes

Bolivia is one of the most biologically diverse countries on the planet. Between the Andes and the Amazon drainage basin spans the Yungas, a vast forested region shown to be extremely species rich in macro-organisms. However, it remains unclear whether this high diversity is also reflected in microbial diversity. Here we assess the genetic, taxonomic and functional diversity of root-associated fungi surrounding Cinchona calisaya calisaya trees, a typical element of the intermediate altitudes of the Bolivian Yungas. We determine the relative effects of edaphic properties, climate, and geography in regulating fungal community assembly. We show that α-diversity for these fungal communities was similar to temperate and arid ecosystems, averaging 90.1 operational taxonomic units (OTUs) per sample, with reads predominantly assigned to the Ascomycota phylum and with a saprotrophic lifestyle. ß-diversity was calculated as the distance-decay rate, and in contrast to α-diversity, was exceptionally high with a rate of -0.407. Soil properties (pH and P) principally regulated fungal community assembly in an analogous manner to temperate environments, with pH and phosphorus explaining 7.8 % and 7.2 % of community variation respectively. Surprisingly, altitude does not influence community formation, and there is limited evidence that climate (precipitation and temperature) play a role. Our results suggest that sampling should be performed over a wide geographical and environmental range in order to capture the full root-associated fungal diversity in subtropical regions. This study sheds further light on the diversity and distribution of the world's hidden biodiversity

Thermally Activated Magnetization and Resistance Decay during Near Ambient Temperature Aging of Co Nanoflakes in a Confining Semi-metallic Environment

We report the observation of magnetic and resistive aging in a self assembled nanoparticle system produced in a multilayer Co/Sb sandwich. The aging decays are characterized by an initial slow decay followed by a more rapid decay in both the magnetization and resistance. The decays are large accounting for almost 70% of the magnetization and almost 40% of the resistance for samples deposited at 35 $^oC$. For samples deposited at 50 $^oC$ the magnetization decay accounts for $\sim 50$ of the magnetization and 50% of the resistance. During the more rapid part of the decay, the concavity of the slope of the decay changes sign and this inflection point can be used to provide a characteristic time. The characteristic time is strongly and systematically temperature dependent, ranging from $\sim1$x$10^2 s$ at 400K to $\sim3$x$10^5 s$ at 320K in samples deposited at $35 ^oC$. Samples deposited at 50 $^oC$ displayed a 7-8 fold increase in the characteristic time (compared to the $35 ^oC$ samples) for a given aging temperature, indicating that this timescale may be tunable. Both the temperature scale and time scales are in potentially useful regimes. Pre-Aging, Scanning Tunneling Microscopy (STM) reveals that the Co forms in nanoscale flakes. During aging the nanoflakes melt and migrate into each other in an anisotropic fashion forming elongated Co nanowires. This aging behavior occurs within a confined environment of the enveloping Sb layers. The relationship between the characteristic time and aging temperature fits an Arrhenius law indicating activated dynamics

Hundred Fifty Years of Herbarium Collections Provide a Reliable Resource of Volatile Terpenoid Profiles Showing Strong Species Effect in Four Medicinal Species of Salvia Across the Mediterranean

Herbarium samples are increasingly being recognized for their potential in answering a wide range of research questions. However, the suitability of herbarium samples for chemical analysis is largely unexplored as they are thought to be too degraded. The aim of this study was to explore terpenoid profiles across time and geographic space for four medicinal species of Salvia across the Mediterranean to assess the suitability of using herbarium specimens in chemical analyses. Herbarium samples of Salvia aethiopis, S. multicaulis, S. officinalis, and S. sclarea collected over 150 years across the Mediterranean were compared to modern samples using both targeted and untargeted gas chromatography-mass spectrometry analysis of terpene profiles. There was no effect of collection year on chemical composition, although the total concentration of the 20 assessed standards and two individual standards significantly decreased over time. Instead, chemical profiles were defined by species, with strong species effects identified on both the targeted and untargeted chemical composition. Geographic variation was a factor in regulating the untargeted chemical compositions, suggesting some underlying environmental effects. However, there was no effect of sample altitude on either the targeted or untargeted chemical compositions. Chemical composition of four Salvia species are predominantly defined by species, and there was a substantially smaller effect of year of sampling. Given these results herbarium collections may well represent a considerably underused resource for chemical analyses that can benefit biodiversity and other studies

Barriers to integrating direct oral anticoagulants into anticoagulation clinic care: A mixedâ methods study

BackgroundOutpatient anticoagulation clinics were initially developed to care for patients taking vitamin K antagonists such as warfarin. There has not been a systematic evaluation of the barriers and facilitators to integrating direct oral anticoagulant (DOAC) care into outpatient anticoagulation clinics.MethodsWe performed a mixed methods study consisting of an online survey of anticoagulation clinic providers and semiâ structured interviews with anticoagulation clinic leaders and managers between March and May of 2017. Interviews were transcribed and coded, exploring for themes around barriers and facilitators to DOAC care within anticoagulation clinics. Survey questions pertaining to the specific themes identified in the interviews were analyzed using summary statistics.ResultsSurvey responses were collected from 159 unique anticoagulation clinics and 20 semiâ structured interviews were conducted. Three primary barriers to DOAC care in the anticoagulation clinic were described by the interviewees: (a) a lack of provider awareness for ongoing monitoring and services provided by the anticoagulation clinic; (b) financial challenges to providing care to DOAC patients in an anticoagulation clinic model; and (c) clinical knowledge versus scope of care by the anticoagulation staff. These themes linked to three key areas of variation, including: (a) the size and hospital affiliation of the anticoagulation clinic; (b) the use of faceâ toâ face versus telephoneâ based care; and (c) the use of nurses or pharmacists in the anticoagulation clinic.ConclusionsAnticoagulation clinics in the United States experience important barriers to integrating DOAC care. These barriers vary based on the clinic size, model for warfarin care, and staff credentials (nursing or pharmacy).Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/147845/1/rth212157.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/147845/2/rth212157_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/147845/3/rth212157-sup-0001-Supinfo.pd