Influences of soil properties on archaeal diversity and distribution in the McMurdo Dry Valleys, Antarctica

The Antarctic Dry Valleys are characterized by extremely low temperatures, arid conditions, high salinity and virtual absence of plants. Therefore, food webs of these microbially dominated soils are among the simplest on earth making these mineral soils a perfect model to study microbial biogeography. This study aims to characterize the distribution and diversity of Archaea within the Dry Valleys as part of the New Zealand Terrestrial Antarctic Biocomplexity Survey (NZTABS). An international multidisciplinary organization focusing on biotic organisms, community structure and their functional linkage to determine what environmental factors drive biocomplexity. Archaea are so far the least known members of the microbial community with only a few successful attempts at detection indicating a patchy distribution and low diversity. A wide range of soil samples, collected from various sites within the Dry Valleys were analyzed using a suite of genetic approaches. DNA fingerprinting techniques (RFLP, T- RFLP) were applied to examine distribution and diversity of archaeal species living in soils of Miers Valley, Marshall Valley, Garwood Valley and Shangri- La. Detailed analysis of physicochemical differences between mineral soils was undertaken in hope to unveil environmental factors driving distribution and biodiversity of archaeal communities present in these soils. Multivariate statistical analysis and ordination of T- RFLP results and physicochemical data revealed a widespread distribution of Archaea across all three valleys, including Shangri- La. Overall, archaeal diversity was relatively low and most of the archaeal communities were composed in majority of one species affiliated with Crenarchaeota Marine Group 1.1b. Archaeal communities that sustain a relatively high diversity appear to be restricted to high elevation ridge areas and coastal moraines. This variation in diversity may be best explained by differences in moisture availability and availability of carbon and nitrogen in mineral soils that harbour these communities. Conversely, soils that harbour high bacterial diversity and primary producers revealed extremely low abundance of Archaea, possibly even total absence of Archaea in these organic rich soils

Molecular evolution and functional characterisation of tunicate xenobiotic receptors

Marine microorganisms generate a wide range of ’bioactive’ compounds that can have far-reaching effects on biological and ecological processes. Metazoans have developed specialised biochemical pathways that metabolise and eliminate potentially toxic chemicals (xenobiotics) from their bodies. The vertebrate xenobiotic receptor, pregnane X receptor (PXR), is a ligand-activated nuclear receptor transcription factor regulating expression of multiple detoxification genes. Ligand-binding domains (LBDs) of vertebrate PXR orthologues may have adaptively evolved to bind toxins typically encountered by these organisms. Marine invertebrate filter-feeders are exposed to relatively high concentrations of xenobiotics associated with their diet. Tunicates (phylum: Chordata) are of particular interest as they form the sister clade to the Vertebrata. Genomes of the solitary tunicate Ciona intestinalis and the colonial tunicate Botryllus schlosseri both encode at least two xenobiotic receptors that are orthologues to both the vertebrate vitamin D receptor (VDR) and PXR. Pursuing the idea that tunicate xenobiotic receptors (VDR/PXR) may adaptively evolve to bind toxic chemicals commonly present in an organism’s environment, this thesis aims to identify if: (i) adaptive evolution is acting on putative tunicate VDR/PXR orthologues to enhance binding of dietary xenobiotics; (ii) these receptors are activated by dietary xenobiotics (e.g. microalgal biotoxins) and; (iii) tunicate VDR/PXR LBDs can be used as sensor elements in yeast bioassays for the detection of both natural and synthetic bioactive compounds. To identify genetic variation and to search for evidence of positive selection, next-generation sequencing was performed on three tunicate VDR/PXR orthologues genes. Recombinant yeast (Saccharomyces cerevisiae) cell lines were developed for the functional characterisation of tunicate VDR/PXR LBDs. These tunicate VDR/PXR LBD-based yeast bioassays were utilised to detect known microalgal biotoxins, natural bioactive compounds, and environmental contaminants. Next-generation sequencing revealed both an unusually high genetic diversity and strong purifying selection in VDR/PXR orthologues from C. intestinalis and B. schlosseri. Single-base-deletion allelic variants were found in C. intestinalis VDR/PXR orthologues resulting in predicted proteins having a DNA-binding domain but lacking a LBD. The persistence of these variants may reflect constitutive expression of detoxification genes as a selective advantage in the marine environment. To assess the functional characteristics of tunicate VDR/PXR orthologues, recombinant yeast cell lines were developed that express VDR/PXRα LBDs from C. intestinalis and B. schlosseri. These chimeric proteins mediate liganddependent expression of a lacZ reporter gene which encodes an easily assayed enzyme (β-galactosidase). These yeast bioassays were highly sensitive towards both synthetic and natural toxins (coefficients of variance, CV <25%). Microalgal biotoxins (okadaic acid and portimine) were two orders of magnitude more potent than synthetic chemicals, which was consistent with the hypothesis that tunicate xenobiotic receptors can bind marine bioactive compounds frequently present in a filter-feeder’s diet. Following these functional studies, the yeast bioassays were tested in a more applied context by screening the following compounds: (i) natural bioactive compounds that represent promising compounds for drug development and; (ii) synthetic chemicals that are common environmental pollutants. Of the 34 compounds tested, 30 were active in the tunicate yeast bioassays. The yeast bioassays were particularly sensitive towards a small number (n = 11) of marine and terrestrial bioactive compounds (CJ-13-014, CJ-13-104, thysanone and naringin) and emerging contaminants such as pharmaceuticals (ketoconazole), antifungals (radicicol), preservatives (butylated hydroxtoluene) and surfactants (oil dispersants), generating CV values <25%. Activities of the remaining 19 compounds were highly variable and appeared to depend on several factors, such as solvent used, duration of exposure and type of recombinant protein expressed (e.g. C. intestinalis versus B. schlosseri VDR/PXRα). In conclusion, the yeast bioassay developed in this thesis, with further development, may provide a template for novel bioassays that may find application in routine microalgal biotoxin testing and environmental monitoring. These bioassays may also assist in the identification of marine bioactive compounds as drug lead compounds

Influence of soil properties on archaeal diversity and distribution in the McMurdo Dry Valleys, Antarctica

Archaea are the least understood members of the microbial community in Antarctic mineral soils. Although their occurrence in Antarctic coastal soils has been previously documented, little is known about their distribution in soils across the McMurdo Dry Valleys, Victoria Land. In this study, terminal-restriction fragment length polymorphism (t-RFLP) analysis and 454 pyrosequencing were coupled with a detailed analysis of soil physicochemical properties to characterize archaeal diversity and identify environmental factors that might shape and maintain archaeal communities in soils of the three southern most McMurdo Dry Valleys (Garwood, Marshall, and Miers Valley). Archaea were successfully detected in all inland and coastal mineral soils tested, revealing a low overall richness (mean of six operational taxonomic units [OTUs] per sample site). However, OTU richness was higher in some soils and this higher richness was positively correlated with soil water content, indicating water as a main driver of archaeal community richness. In total, 18 archaeal OTUs were detected, predominately Thaumarchaeota affiliated with Marine Group 1.1b (> 80% of all archaeal sequences recovered). Less abundant OTUs (2% of all archaeal sequences) were loosely related to members of the phylum Euryarchaeota. This is the first comprehensive study showing a widespread presence and distribution of Archaea in inland Antarctic soils

Understanding young people's transitions in university halls through space and time

This article contributes to the theoretical discussion about young people's transitions through space and time. Space and time are complex overarching concepts that have creative potential in deepening understanding of transition. The focus of this research is young people's experiences of communal living in university halls. It is argued that particular space-time concepts draw attention to different facets of experience and in combination deepen the understanding of young people's individual and collective transitions. The focus of the article is the uses of the space-time concepts 'routine', 'representation', 'rhythm' and 'ritual' to research young people's experiences. The article draws on research findings from two studies in the North of England. © 2010 SAGE Publications

The Minimum Important Difference for the International Consultation on Incontinence Questionnaire-Urinary Incontinence Short Form in Women with Stress Urinary Incontinence

INTRODUCTION: Minimum important difference (MID) estimates the minimum degree of change in an instrument\u27s score that correlates with a patient\u27s subjective sense of improvement. We aimed to determine the MID for the International Consultation on Incontinence Questionnaire-Urinary Incontinence Short Form (ICIQ-UI SF) using both anchor based and distribution based methods derived using data from the Trial of Midurethral Slings (TOMUS). MATERIALS AND METHODS: Instruments for the anchor-based analyses included the urogenital distress inventory (UDI), incontinence impact questionnaire (IIQ), patient global impression of improvement (PGI-I), incontinence episodes (IE) on 7-day bladder diary, and satisfaction with surgical results. After confirming moderate correlation (r ≥ 0.3) of ICIQ-UI SF and each anchor, MIDs were determined by calculating the difference between the mean instrument scores for individuals with the smallest amount of improvement and with no change. The distribution-based method of MID assessment was applied using effect sizes of 0.2 and 0.5 SD (small to medium effects). Triangulation was used to examine these multiple MID values in order to converge on a small range of values. RESULTS: Anchor-based MIDs range from -4.5 to -5.7 at 12 months and from -3.1 to 4.3 at 24 months. Distribution-based MID values were lower. Triangulation analysis supports a MID of -5 at 12 months and -4 at 24 months. CONCLUSION: The recommended MIDs for ICIQ-UI SF are -5 at 12 months and -4 at 24 months. In surgical patients, ICIQ-UI SF score changes that meet these thresholds can be considered clinically meaningful

Higher frequencies of BCRP+ cardiac resident cells in ischaemic human myocardium

Aims Several cardiac resident progenitor cell types have been reported for the adult mammalian heart. Here we characterize their frequencies and distribution pattern in non-ischaemic human myocardial tissue and after ischaemic events. Methods and results We obtained 55 biopsy samples from human atria and ventricles and used immunohistological analysis to investigate two cardiac cell types, characterized by the expression of breast cancer resistance protein (BCRP)/ABCG2 [for side population (SP) cells] or c-kit. Highest frequencies of BCRP+ cells were detected in the ischaemic right atria with a median of 5.40% (range: 2.48-11.1%) vs. 4.40% (1.79-7.75%) in the non-ischaemic right atria (P = 0.47). Significantly higher amounts were identified in ischaemic compared with non-ischaemic ventricles, viz. 5.44% (3.24-9.30%) vs. 0.74% (0-5.23%) (P = 0.016). Few numbers of BCRP+ cells co-expressed the cardiac markers titin, sarcomeric α-actinin, or Nkx2.5; no co-expression of BCRP and progenitor cell marker Sca-1 or pluripotency markers Oct-3/4, SSEA-3, and SSEA-4 was detected. C-kit+ cells displayed higher frequencies in ischaemic (ratio: 1:25 000 ± 2500 of cell counts) vs. non-ischaemic myocardium (1:105 000 ± 43 000). Breast cancer resistance protein+/c-kit+ cells were not identified. Following in vitro differentiation, BCRP+ cells isolated from human heart biopsy samples (n = 6) showed expression of cardiac troponin T and α-myosin heavy-chain, but no full differentiation into functional beating cardiomyocytes was observed. Conclusion We were able to demonstrate that BCRP+/CD31− cells are more abundant in the heart than their c-kit+ counterparts. In the non-ischaemic hearts, they are preferentially located in the atria. Following ischaemia, their numbers are elevated significantly. Our data might provide a valuable snapshot at potential progenitor cells after acute ischaemia in vivo, and mapping of these easily accessible cells may influence future cell therapeutic strategie

Adherence to Antihypertensive Drugs Assessed by Hyphenated High-Resolution Mass Spectrometry Analysis of Oral Fluids

Background It is currently unknown if antihypertensive drugs can be monitored in oral fluid (OF) using liquid chromatography coupled to high-resolution mass spectrometry. Methods and Results We assessed adherence using liquid chromatography coupled to high-resolution mass spectrometry in OF, plasma, and urine of 56 consecutive patients with hypertension referred to a tertiary hypertension unit. Of these patients, 59% were completely adherent (all drugs detectable in urine), whereas 29% and 13% were partially adherent (1 drug not detectable in urine) or nonadherent (>1 drug not detectable in urine), respectively. Adherent patients were on fewer antihypertensive drugs (P=0.001), had fewer daily drug doses (P=0.012), and had lower 24-hour ambulatory systolic (P=0.012) and diastolic (P=0.009) blood pressures than nonadherent or partially adherent patients. Most drugs were detected in urine compared with plasma and OF (181 versus 119 versus 88; P=0.001). Compared with urine and plasma, detection rates of angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, and diuretics were lower in OF. There was no difference in the frequency of detecting β blockers (P=1.0) and calcium channel blockers (P=0.063) when comparing OF with urine. There was no difference in the number of calcium channel blockers (P=0.727), β blockers (P=1.000), thiazide diuretics (P=0.125), and α-2 agonists (P=0.125) identified between OF and plasma. Conclusions This study shows the feasibility of drug adherence testing for several antihypertensive drugs, especially those without acidic components, in OF, with a similar recovery compared with plasma. Therefore, drug adherence testing in OF should be further explored as a noninvasive approach, which can easily be performed in an "out-of-office" setting

Incontinence pessaries: size, POPQ measures, and successful fitting

The aim of the study was to determine whether successful incontinence pessary fitting or pessary size can be predicted by specific POPQ measurements in women without advanced pelvic organ prolapse. In a multicenter study, women with stress urinary incontinence (SUI) and POPQ stage ≤2 were randomized to three treatment arms: (1) incontinence pessary, (2) behavioral therapy, or (3) both. This study evaluates incontinence pessary size, POPQ measures, and successful fitting in the 266 women assigned to treatment arms 1 and 3. Two hundred thirty-five women (92%) were successfully fitted with an incontinence ring (n = 122) or dish (n = 113). Hysterectomy, genital hiatus (GH), and GH/total vaginal length (TVL) ratios did not predict unsuccessful fitting (p &gt; 0.05). However, mean TVL was greater in women successfully fitted (9.6 vs. 8.8 cm, p &lt; 0.01). Final pessary diameter was not predicted by TVL, point D, or point C (p &gt; 0.05). The vast majority of women with SUI can be successfully fitted with an incontinence pessary, but specific POPQ measures were not helpful in determining incontinence pessary size