51 research outputs found
New phagotrophic euglenoid species (new genus Decastava; Scytomonas saepesedens; Entosiphon oblongum), Hsp90 introns, and putative euglenoid Hsp90 pre-mRNA insertional editing
We describe three new phagotrophic euglenoid species by light microscopy and 18S rDNA and Hsp90 sequencing: Scytomonas saepesedens; Decastava edaphica; Entosiphon oblongum. We studied Scytomonas and Decastava ultrastructure. Scytomonas saepesedens feeds when sessile with actively beating cilium, and has five pellicular strips with flush joints and Calycimonas-like microtubule-supported cytopharynx. Decastava, sister to Keelungia forming new clade Decastavida on 18S rDNA trees, has 10 broad strips with cusp-like joints, not bifurcate ridges like Ploeotia and Serpenomonas (phylogenetically and cytologically distinct genera), and Serpenomonas-like feeding apparatus (8–9 unreinforced microtubule pairs loop from dorsal jaw support to cytostome). Hsp90 and 18S rDNA trees group Scytomonas with Petalomonas and show Entosiphon as the earliest euglenoid branch. Basal euglenoids have rigid longitudinal strips; derived clade Spirocuta has spiral often slideable strips. Decastava Hsp90 genes have introns. Decastava/Entosiphon Hsp90 frameshifts imply insertional RNA editing. Petalomonas is too heterogeneous in pellicle structure for one genus; we retain Scytomonas (sometimes lumped with it) and segregate four former Petalomonas as new genus Biundula with pellicle cross section showing 2–8 smooth undulations and typified by Biundula (=Petalomonas) sphagnophila comb. n. Our taxon-rich site-heterogeneous rDNA trees confirm that Heteronema is excessively heterogeneous; therefore we establish new genus Teloprocta for Heteronema scaphurum
Quantifying Therapeutic and Diagnostic Efficacy in 2D Microvascular Images
VESGEN is a newly automated, user-interactive program that maps and quantifies the effects of vascular therapeutics and regulators on microvascular form and function. VESGEN analyzes two-dimensional, black and white vascular images by measuring important vessel morphology parameters. This software guides the user through each required step of the analysis process via a concise graphical user interface (GUI). Primary applications of the VESGEN code are 2D vascular images acquired as clinical diagnostic images of the human retina and as experimental studies of the effects of vascular regulators and therapeutics on vessel remodeling
Articles Prevalence and burden of HCV co-infection in people living with HIV: a global systematic review and meta-analysis
Summary Background At global level, there are 37 million people infected with HIV and 115 million people with antibodies to hepatitis C virus (HCV). Little is known about the extent of HIV-HCV co-infection. We sought to characterise the epidemiology and burden of HCV co-infection in people living with HIV
New discoveries in the transmission biology of sleeping sickness parasites: applying the basics
The sleeping sickness parasite, Trypanosoma brucei, must differentiate in response to the changing environments that it encounters during its complex life cycle. One developmental form, the bloodstream stumpy stage, plays an important role in infection dynamics and transmission of the parasite. Recent advances have shed light on the molecular mechanisms by which these stumpy forms differentiate as they are transmitted from the mammalian host to the insect vector of sleeping sickness, tsetse flies. These molecular advances now provide improved experimental tools for the study of stumpy formation and function within the mammalian bloodstream. They also offer new routes to therapy via high-throughput screens for agents that accelerate parasite development. Here, we shall discuss the recent advances that have been made and the prospects for future research now available
Post-transcriptional control of nuclear-encoded cytochrome oxidase subunits in Trypanosoma brucei: evidence for genome-wide conservation of life-cycle stage-specific regulatory elements
Trypanosomes represent an excellent model for the post-transcriptional regulation of gene expression because their genome is organized into polycistronic transcription units. However, few signals governing developmental stage-specific expression have been identified, with there being no compelling evidence for widespread conservation of regulatory motifs. As a tool to search for common regulatory sequences we have used the nuclear-encoded components of the cytochrome oxidase (COX) complex of the trypanosome respiratory chain. Components of this complex represent a form of post-transcriptional operon because trypanosome mitochondrial activity is unusual in being developmentally programmed. By genome analysis we identified the genes for seven components of the COX complex. Each mRNA exhibits bloodstream stage-specific instability, which is not mediated by the RNA silencing pathway but which is alleviated by cycloheximide. Reporter assays have identified regulatory regions within the 3′-untranslated regions of three COX mRNAs operating principally at the translational level, but also via mRNA stability. Interrogation of the mapped regions via oligonucleotide frequency scoring provides evidence for genome-wide conservation of regulatory sequences among a large cohort of procyclic-enriched transcripts. Analysis of the co-regulated subunits of a stage-specific enzyme is therefore a novel approach to uncover cryptic regulatory sequences controlling gene expression at the post-transcriptional level
Comparison of empirically derived and model-based estimates of key population HIV incidence and the distribution of new infections by population group in sub-Saharan Africa
Background: The distribution of new HIV infections among key populations, including female sex workers (FSWs), gay men and other men who have sex with men (MSM), and people who inject drugs (PWID) are essential information to guide an HIV response, but data are limited in sub-Saharan Africa (SSA). We analyzed empirically derived and mathematical model-based estimates of HIV incidence among key populations and compared with the Joint United Nations Programme on HIV/AIDS (UNAIDS) estimates.Methods: We estimated HIV incidence among FSW and MSM in SSA by combining meta-analyses of empirical key population HIV incidence relative to the total population incidence with key population size estimates (KPSE) and HIV prevalence. Dynamic HIV transmission model estimates of HIV incidence and percentage of new infections among key populations were extracted from 94 country applications of 9 mathematical models. We compared these with UNAIDS-reported distribution of new infections, implied key population HIV incidence and incidence-to-prevalence ratios.Results: Across SSA, empirical FSW HIV incidence was 8.6-fold (95% confidence interval: 5.7 to 12.9) higher than total population female 15–39 year incidence, and MSM HIV incidence was 41.8-fold (95% confidence interval: 21.9 to 79.6) male 15–29 year incidence. Combined with KPSE, these implied 12% of new HIV infections in 2021 were among FSW and MSM (5% and 7% respectively). In sensitivity analysis varying KPSE proportions within 95% uncertainty range, the proportion of new infections among FSW and MSM was between 9% and 19%. Insufficient data were available to estimate PWID incidence rate ratios. Across 94 models, median proportion of new infections among FSW, MSM, and PWID was 6.4% (interquartile range 3.2%–11.7%), both much lower than the 25% reported by UNAIDS.Conclusion: Empirically derived and model-based estimates of HIV incidence confirm dramatically higher HIV risk among key populations in SSA. Estimated proportions of new infections among key populations in 2021 were sensitive to population size assumptions and were substantially lower than estimates reported by UNAIDS.</div
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Investigation of Accelerated Casing Corrosion in Two Wells at Waste Management Area A-AX
This report was revised in September 2008 to remove acid-extractable sodium data from Tables 3.13 and 3.14. The sodium data was removed due to potential contamination introduced during the acid extraction process. The rest of the text remains unchanged from the original report issued in August 2005. An overall goal of the Groundwater Performance Assessment Project, led by Pacific Northwest National Laboratory (PNNL) and per guidance in DOE Order 5400.1, includes characterizing and defining trends in the physical, chemical, and biological condition of the environment. To meet these goals, numerous Resource Conservation and Recovery Act (RCRA) monitoring wells have been installed throughout the Hanford Site. In 2003, it was determined that two RCRA monitoring wells (299-E24-19 and 299-E25-46) in Waste Management Area (WMA) A-AX failed due to rapid corrosion of the stainless steel casing over a significant length of the wells. Complete casing corrosion occurred between 276.6 and 277.7 feet below ground surface (bgs) in well 299- E24-19 and from 274.4 to 278.6 feet bgs in well 299-E25-46. CH2M HILL Hanford Group, Inc., asked scientists from PNNL to perform detailed analyses of vadose zone sediment samples collected in the vicinity of the WMA A-AX from depths comparable to those where the rapid corrosion occurred in hopes of ascertaining the cause of the rapid corrosion
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Characterization of Vadose Zone Sediments Below the C Tank Farm: Borehole C4297 and RCRA Borehole 299-E27-22
The overall goal of the Tank Farm Vadose Zone Project, led by CH2M HILL Hanford Group, Inc., is to define risks from past and future single-shell tank farm activities at Hanford. To meet this goal, CH2M HILL Hanford Group, Inc. tasked scientists from Pacific Northwest National Laboratory to perform detailed analyses on vadose zone sediments from within Waste Management Area (WMA) C. This report is the first of two reports written to present the results of these analyses. Specifically, this report contains all the geologic, geochemical, and selected physical characterization data collected on vadose zone sediment recovered from borehole C4297, installed adjacent to Tank C-105, and from borehole 299-E27-22, installed directly north of the C Tank Farm. Sediments from borehole 299-E27-22 were considered to be background uncontaminated sediments against which to compare contaminated sediments for the C Tank Farm characterization effort. This report also presents our interpretation of the data in the context of sediment types, the vertical extent of contamination, the migration potential of the contaminants, and the likely source of the contamination in the vadose zone and groundwater below the C Tank Farm. The information presented in this report supports the A-AX, C and U Waste Management Area field investigation report(a) in preparation by CH2M HILL Hanford Group, Inc. A core log was generated for both boreholes and a geologic evaluation of all core samples was performed at the time of opening. Aliquots of sediment from the borehole core samples were analyzed and characterized in the laboratory for the following parameters: moisture content, gamma-emitting radionuclides, one-to-one water extracts (which provide soil pH, electrical conductivity, cation, trace metal, and anion data), total carbon and inorganic carbon content, and 8 M nitric acid extracts (which provide a measure of the total leachable sediment content of contaminants). Two key radiocontaminants, technetium-99 and uranium-238, along with other trace metals were determined in acid and water extracts by inductively coupled plasma mass spectrometry
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