Nucleic acid aptamers as aptasensors for plant biology

Our knowledge of cell- and tissue-specific quantification of phytohormones is heavily reliant on laborious mass spectrometry techniques. Genetically encoded biosensors have allowed spatial and some temporal quantification of phytohormones intracellularly, but there is still limited information on their intercellular distributions. Here, we review nucleic acid aptamers as an emerging biosensing platform for the detection and quantification of analytes with high affinity and specificity. Options for DNA aptamer technology are explained through selection, sequencing analysis and techniques for evaluating affinity and specificity, and we focus on previously developed DNA aptamers against various plant analytes. We suggest how these tools might be applied in planta for quantification of molecules of interest both intracellularly and intercellularly

Hydrophilic polymeric coatings for enhanced, serial-siphon based flow control on centrifugal lab-on-disc platforms

In this paper, we implement rotational flow control on a polymeric microfluidic “lab-on-a-disc” device by combining serial siphoning and capillary valving for sequential release of on-board stored liquid reagents. The functionality of this integrated, multi-step centrifugal assay platform is tightly linked by the capability to establish reproducible, capillary-driven priming of the innately hydrophobic siphon microchannels. We here demonstrate for the first time that spin-coated hydrophilic polymeric films of poly(vinyl alcohol) and (hydroxylpropyl)methylcellulose provide stable contact angles

Effects of maternal stress and obesity on human feto-placental glucocorticoid exposure

Fetal exposure to excess glucocorticoids has been proposed as a key determinant of pregnancy outcome, as well as a predictor of long term health of the offspring through a phenomenon known as ‘developmental programming’. Obesity and ‘stress’ during pregnancy are two potential sources of altered fetal exposure to glucocorticoids. One in five pregnant women is obese at antenatal booking, and maternal obesity increases risk of offspring complications including higher birth weight, potentially leading to long-term programming effects on the offspring. Likewise, maternal anxiety during pregnancy has been identified as a programming factor, increasing the risk of psychopathology in the offspring. This thesis tests the hypothesis that in humans this association is mediated by altered action of glucocorticoids, by examining circulating levels of maternal glucocorticoids during pregnancy and through measurement of key genes in the placenta regulating fetal glucocorticoid exposure. Serum cortisol levels were measured at 16, 28 and 36 weeks gestation in n=173 class III obese (BMI 44.0±4.5kg/m2) and n=107 lean (BMI 22.8±1.6kg/m2) pregnant women. Serial corticosteroid binding globulin (CBG) concentrations were measured in a subset (n=39 lean, 26 obese) and free cortisol levels calculated using Coolen’s equation. CRH concentrations were measured at the same time points in obese (n=20) and lean (n=22) pregnant women Salivary cortisol was measured in samples collected at bed-time, waking and 30 minutes after waking. mRNA levels of candidate genes regulating glucocorticoids and fetal/placental growth including 11-beta hydroxysteroid dehydrogenase type 2 (11βHSD2), which inactivates cortisol, insulin-like growth factor 2 (IGF2) and glucocorticoid receptor (GR) were measured in first trimester (n=32), second trimester (n=15) and term (n=60) placental samples. DNA methylation of key regions controlling the expression of the IGF2, GR and 11βHSD2 genes was measured by pyrosequencing in first trimester and term samples. Levels of mRNAs encoding 11βHSD1, 11βHSD2, GR and MR were measured in term placentas collected from women from Helsinki, Finland in whom anxiety during pregnancy had been prospectively assessed using validated questionnaires. Term placental samples from a subset of the obese and lean women who had also completed stress questionnaires during pregnancy were used to examine replication of findings. Cortisol levels rose similarly during pregnancy in obese and lean but were significantly lower throughout pregnancy in obese women (p<0.05). The diurnal rhythm of cortisol was maintained. CBG levels also increased, though this change was lower in obese (1.21-fold (±0.9) vs 1.56-fold (±0.07), p<0.01). In obese women, lower calculated free cortisol at 16 weeks gestation was associated with higher birth weight after adjustment for other factors (r=-0.46, p<0.05). Placental mRNA encoding 11βHSD2 increased in association with increasing obesity in early pregnancy (r=0.44, p<0.01) and was highest in term placenta in obese women with macrosomic (>4000g) offspring (p<0.05). Placental transcript abundance of GR also increased in association with increasing obesity in early pregnancy (r=0.38, p<0.05), but was lowest in term placenta from obese with macrosomic offspring (p<0.05). IGF2 mRNA abundance was lower in the placentas of obese women with macrosomic offspring at term compared to both lean women and obese women with normal weight offspring (p<0.01). Methylation results are reported. Placental mRNA levels encoding 11βHSD1 (which converts inactive cortisone to active cortisol) at term was found to positively associate with maternal anxiety measured in the first trimester of pregnancy in a group of pregnant Finnish women (β=0.3, p<0.05). Findings were similar in the replication sample in lean women only (β=4.6, p<0.05). Lower circulating and bioavailable cortisol levels in early pregnancy, together with a greater placental ‘barrier’ to maternal glucocorticoids represent key mechanisms contributing to higher birth weight in offspring of obese women. Regeneration of active glucocorticoids in placenta and increasing placental sensitivity to glucocorticoids increases fetal glucocorticoid exposure and offers insight into the biological mechanisms underlying adverse offspring effects of maternal prenatal anxiety

PROJECTING THE IMPACT OF DEMOGRAPHIC CHANGE ON THE DEMAND FOR AND DELIVERY OF HEALTH CARE IN IRELAND. RESEARCH SERIES NUMBER 13 OCTOBER 2009

Primary care is often the first point of contact with the health care system for people requiring care. Primary care is often thought synonymous with general practitioners, but actually encompasses a large range of different professionals and services including nurses/midwives; physiotherapists; occupational therapists; dentists; opticians; chiropodists; psychologists and pharmacists. The list is not exhaustive, but still gives an indication of the wide range of services that can be grouped under the general heading of primary care. Nonetheless, GPs do have a core part to play in primary care as well as performing the role of ‘gate keeper’ to other health services such as accident and emergency or outpatient care in hospitals. The balance of treatment and referral between general practice and secondary care is, therefore, a very important issue and it has been argued that the under development of primary care services in Ireland in recent decades has contributed, and indeed, may be the most important reason, for the over-crowding of accident and emergency services and long waiting lists for elective procedures in Irish health care (Layte et al., 2007b; Tussing and Wren, 2006)

Molecular analysis of Candidate genes at the 22q region in Schizophrenia subjects

22q11.2 deletion syndrome (22q11.2DS), also known as Velo-Cardio-Facial Syndrome (VCFS) or DiGeorge Syndrome, is a genetic disorder due to a micro deletion on chromosome 22q11.2. VCFS is associated with abnormalities in brain structure and with an increased risk of psychiatric disorders, particularly schizophrenia (SCZ). DNA copy  number is a largely unexplored source of human genetic variation that may contribute risk for complex disease like SCZ. The aim of this study was to assess Copy number variations (CNV) at candidate genes located in 22q11 region in SCZ subjects. We report aberrations in copy number  at PRODH and COMT gene loci supporting the hypothesis that dosage effects of 22q genes could lead to disruptions in neurotransmitter signaling and related neurobehavioral symptoms observed in SCZ subjects. The results support the hypothesis that the complex phenotype of 22qDS results either from the overlapping regulation of several genes within this region or from its concerted participation in a highly regulated process

Global Burden of Disease of Mercury Used in Artisanal Small-Scale Gold Mining

BACKGROUND Artisanal small-scale gold mining (ASGM) is the world's largest anthropogenic source of mercury emission. Gold miners are highly exposed to metallic mercury and suffer occupational mercury intoxication. The global disease burden as a result of this exposure is largely unknown because the informal character of ASGM restricts the availability of reliable data. OBJECTIVE To estimate the prevalence of occupational mercury intoxication and the disability-adjusted life years (DALYs) attributable to chronic metallic mercury vapor intoxication (CMMVI) among ASGM gold miners globally and in selected countries. METHODS Estimates of the number of artisanal small-scale gold (ASG) miners were extracted from reviews supplemented by a literature search. Prevalence of moderate CMMVI among miners was determined by compiling a dataset of available studies that assessed frequency of intoxication in gold miners using a standardized diagnostic tool and biomonitoring data on mercury in urine. Severe cases of CMMVI were not included because it was assumed that these persons can no longer be employed as miners. Cases in workers' families and communities were not considered. Years lived with disability as a result of CMMVI among ASG miners were quantified by multiplying the number of prevalent cases of CMMVI by the appropriate disability weight. No deaths are expected to result from CMMVI and therefore years of life lost were not calculated. Disease burden was calculated by multiplying the prevalence rate with the number of miners for each country and the disability weight. Sensitivity analyses were performed using different assumptions on the number of miners and the intoxication prevalence rate. FINDINGS Globally, 14-19 million workers are employed as ASG miners. Based on human biomonitoring data, between 25% and 33% of these miners-3.3-6.5 million miners globally-suffer from moderate CMMVI. The resulting global burden of disease is estimated to range from 1.22 (uncertainty interval [UI] 0.87-1.61) to 2.39 (UI 1.69-3.14) million DALYs. CONCLUSIONS This study presents the first global and country-based estimates of disease burden caused by mercury intoxication in ASGM. Data availability and quality limit the results, and the total disease burden is likely undercounted. Despite these limitations, the data clearly indicate that mercury intoxication in ASG miners is a major, largely neglected global health problem

Baseline bioavailable strontium isotope values for the investigation of residential mobility and resource-acquisition strategies in prehistoric Cambodia

Strontium (Sr) isotope ratios (87Sr/86Sr) measured in human skeletal material can increase one's understanding of the residential behaviour and resource‐acquisition strategies of past populations. The paper maps bioavailable 87Sr/86Sr variation in 183 plant and soil samples across Cambodia. Bioavailable 87Sr/86Sr, as measured in plants, differs significantly between four major geological units. The data set will support future investigations of skeletal material from Cambodian archaeological sites. Baseline 87Sr/86Sr data should be applied judiciously to skeletal populations, and in concert with other lines of evidence, to identify potential geographical outliers rather than to ascribe specific locations from which individuals may have movedThey thank the Australian Research Council for supporting the research through the Discovery Grants programme (grantnumbers DP0984968 and DP110101997)