Synchrotron Radiation X-Ray Microfluorescence Reveals Polarized Distribution of Atomic Elements during Differentiation of Pluripotent Stem Cells

The mechanisms underlying pluripotency and differentiation in embryonic and reprogrammed stem cells are unclear. In this work, we characterized the pluripotent state towards neural differentiated state through analysis of trace elements distribution using the Synchrotron Radiation X-ray Fluorescence Spectroscopy. Naive and neural-stimulated embryoid bodies (EB) derived from embryonic and induced pluripotent stem (ES and iPS) cells were irradiated with a spatial resolution of 20 µm to make elemental maps and qualitative chemical analyses. Results show that these embryo-like aggregates exhibit self-organization at the atomic level. Metallic elements content rises and consistent elemental polarization pattern of P and S in both mouse and human pluripotent stem cells were observed, indicating that neural differentiation and elemental polarization are strongly correlated

Future landscapes in South-eastern Australia : the role of protected areas and biolinks in adaptation to climate change

The extent and rapidity of global climate change is the major novel threatening process to biodiversity in the 21 st century. Globally, numerous studies suggest movement of biota to higher latitudes and altitudes with increasing empirical -evidence emerging. As biota responds to the direct and consequent effects of climate change the potential to profoundly affect natural systems (including the reserve system) of south-eastern Australia is becoming evident. Climate change is projected to accelerate major environmental drivers such as drought, fire and flood regimes. Is the reserve system sufficient for biodiversity conservation under a changing climate? Australia is topographically flat, biologically mega-diverse with high species endemism, and has the driest and most variable climate of any inhabited continent. Whilst the north-south orientation and aftitude gradient of eastern Australia\u27s forests and woodlands provides some resilience to projected climatic change, this has been eroded since European settlement, particularly in the cool-moist Bassian zone of the south-east. Following settlement, massive land-use change for agriculture and forestry caused widespread loss and fragmentation of habitats; becoming geriatric in agricultural landscapes and artificially young in forests. The reserve system persists as an archipelago of ecological islands surrounded by land uses of varying compatibility with conservation and vulnerable to global warming. The capacity for biota to adapt is limited by habitat availability. The extinction risk is exacerbated. Re-examination of earlier analysis of ecological connectivity through biolink zones confirms biolinks as an appropriate risk management response within a broader suite of measures. Areas not currently in the reserve system may be critical to the value and ecological function of biological assets of the reserve system as these assets change. Ecological need and the rise of ecosystem services, combined with changing socio-economic drivers of land-use and social values that supported the expansion of the reserve system, all suggest biolink zones represent a new, necessary and viable multi-functional landscape. This paper explores some of the key ecological elements for restoration within biolink zones (and landscapes at large) particularly through currently agricultural landscapes.<br /

Agricultural intensification and loss of matrix habitat over 23 years in the West Wimmera, south-eastern Australia

The global trend toward more intensive forms of agriculture is changing the nature of matrix habitat in agricultural areas. Removal of components of matrix habitat can affect native biota at the paddock and the landscape scale, particularly where intensification occurs over large areas. We identify the loss of paddock trees due to the proliferation of centre pivot irrigation in dryland farming areas as a potentially serious threat to the remnant biota of these areas. We used a region of south-eastern Australia as a case study to quantify land use change from grazing and dryland cropping to centre pivot irrigation over a 23-year period. We also estimated rates of paddock tree loss in 5 representative landscapes within the region over the same period. The total area affected by centre pivots increased from 0 ha in 1980 to nearly 9000 ha by 2005. Pivots were more likely to be established in areas which had originally been plains savannah and woodlands containing buloke (Allocasuarina luehmannii), a food source for an endangered bird. On average, 42% of paddock buloke trees present in 1982 were lost by 2005. In the two landscapes containing several centre pivots, the loss was 54% and 70%. This accelerated loss of important components of matrix habitat is likely to result in species declines and local extinctions. We recommend that measures to alleviate the likely negative impacts of matrix habitat loss on native biota be considered as part of regional planning strategies

The relationship between methamphetamine and popper use and risk of HIV seroconversion in the multicenter AIDS cohort study

BACKGROUND: The association between methamphetamine use and HIV seroconversion for men who have sex with men (MSM) was examined using longitudinal data from the Multicenter AIDS Cohort Study. METHODS: Seronegative (n = 4003) men enrolled in 1984 to 1985, 1987 to 1991, and 2001 to 2003 were identified. Recent methamphetamine and popper use was determined at the current or previous visit. Time to HIV seroconversion was the outcome of interest. Covariates included race/ethnicity, cohort, study site, educational level, number of sexual partners, number of unprotected insertive anal sexual partners, number of unprotected receptive anal sexual partners, insertive rimming, cocaine use at the current or last visit, ecstasy use at the current or last visit, any needle use since the last visit, Center for Epidemiologic Study of Depression symptom checklist score >16 since the last visit, and alcohol consumption. RESULTS: After adjusting for covariates, there was a 1.46 (95% confidence interval [CI]: 1.12 to 1.92) increased relative hazard of HIV seroconversion associated with methamphetamine use. The relative hazard associated with popper use was 2.10 (95% CI: 1.63 to 2.70). The relative hazard of HIV seroconversion increased with the number of unprotected receptive anal sexual partners, ranging from 1.87 (95% CI: 1.40 to 2.51) for 1 partner to 9.32 (95% CI: 6.21 to 13.98) for 5+ partners. The joint relative hazard for methamphetamine and popper use was 3.05 (95% CI: 2.12 to 4.37). There was a significant joint relative hazard for methamphetamine use and number of unprotected receptive anal sexual partners of 2.71 (95% CI: 1.81 to 4.04) for men with 1 unprotected receptive anal sexual partner, which increased in a dose-dependent manner for >1 partners. CONCLUSIONS: Further examination of the mechanisms underlying the synergism of drug use and sexual risk behaviors on rates of HIV seroconversion is necessary for the development of new targeted HIV prevention strategies for nonmonogamous drug-using MSM. © 2007 Lippincott Williams & Wilkins, Inc

Osteopenia in Sparc (osteonectin) deficient mice: characterization of phenotypic determinants of femoral strength and changes in gene expression

Sparc null mutants have been generated independently via targeted mutations in exons 4 and 6. Previous studies have identified low-turnover osteopenia in the 129Sv/C57BL/6 exon 4 knockout. Since both Sparc null mutations result in complete absence of Sparc protein, similar phenotypic outcomes are likely. However, genetic background (strain) and/or linkage disequilibrium effects can influence phenotype. Different inactivating mutations should be tested in various mouse strains; similar phenotypic outcomes can then confidently be assigned to the mutated gene. We have evaluated the bone phenotype in the 129Sv/EvSparctm1cam exon 6 knockout at 4 and 9 mo, using physical measurement, mechanical strength tests, and DXA scanning. We have also quantified bone marrow adiposity and circulating leptin levels to assess adipose tissue metabolism. 129Sv/EvSparctm1cam null mice show decreased bone mineral density and bone mineral content and increased mechanical fragility of bone, in line with previous studies. Differences were also noted. Increased body weight and levels of bone marrow adiposity but decreased circulating leptin concentrations were identified at 4, but not 9 mo, and 129Sv/EvSparctm1cam null mice also had shorter femurs. Molecular phenotyping was carried out using mouse HGMP NIA microarrays with cortical femur samples at various ages, using semiquantitative RT-PCR validation. We identified 429 genes highly expressed in normal bone. Six genes (Sparc, Zfp162, Bysl, E2F4, two ESTs) are differentially regulated in 129Sv/EvSparctm1cam cortical femur vs. 129Sv/Ev controls. We confirm low-turnover osteopenia as a feature of the Sparc null phenotype, identifying the usefulness of this mouse as a model for human osteoporosis

1H, 15N, and 13C chemical shift assignments of murine calcium-binding protein 4

Calcium-binding protein 4 (CaBP4) regulates voltage-gated Ca(2+) channels in retinal rod cells and specific mutations within CaBP4 are associated with congenital stationary night blindness type 2. We report complete NMR chemical shift assignments of the Ca(2+)-saturated form of CaBP4 with Ca(2+) bound at EF1, EF3 and EF4 (BMRB no. 18877)

A randomized trial of a behavioral intervention for black MSM: The DiSH study

Objective: To test a new behavioral intervention for black MSM in reducing sexual risk and increasing social support and intentions to use condoms. Design: A single-site, unblinded randomized trial in New York City with 3-month follow-up. Methods: Participants (n=283) reporting at least two sexual partners and unprotected anal intercourse with a man in the past 3 months were enrolled and randomized to a social-cognitive theory-based intervention or control comparison. Men in the intervention group participated in five 2-h group sessions focused on creating a group environment with sexual risk-reduction information and exercises woven into joint meal preparation and sharing activities, while exploring self-efficacy perceptions and outcome expectancies. Intervention (n=142) and control (n=141) groups received standard HIV counseling and testing at baseline. Results: No significant differences were found between study arms at 3 months in number of male partners, number of unprotected anal intercourse partners, proportion reporting unprotected sex, number of acts protected by condoms, self-efficacy, condom attitudes, condom intentions, social isolation and psychological distress. In both arms combined, declines from baseline to 3 months were observed in sexual risk behaviors, social isolation and psychological distress, whereas self-efficacy, condom attitudes and condom intentions improved. Conclusion: As the HIV epidemic continues to have a dramatic impact on black MSM in the USA, the urgency to design innovative interventions continues. © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins