Comparative proteomic analysis to study molecular events during gonad development in mice

Sex determination represents a critical bifurcation in the road of embryonic development. It is based on a finely regulated network of gene activity, as well as protein-protein interactions and activation or silencing of signaling pathways. Despite the identification of a number of critical genes, many aspects of the molecular cascade that drives the differentiation of the embryonic gonad into either a testis or an ovary remain poorly understood. To identify new proteins involved in this cascade, we employed two-dimensional gel electrophoresis and mass spectrometry to compare the protein expression profiles of fetal mouse testes and ovaries. Three proteins, hnRPA1, TRA1, and HSC71, were found to be expressed in a male-specific manner and this expression was confirmed by real-time reverse transcriptase polymerase chain reaction (RT-PCR) and in situ hybridization. Moreover, HSC71 was found to be hyperphosphorylated in male compared to female gonads, emphasizing the advantage of the proteomic approach in allowing the detection of posttranslational modifications.

Development and evaluation of a youth mental health community awareness campaign - The Compass Strategy

Background: Early detection and treatment of mental disorders in adolescents and young adults can lead to better health outcomes. Mental health literacy is a key to early recognition and help seeking. Whilst a number of population health initiatives have attempted to improve mental health literacy, none to date have specifically targeted young people nor have they applied the rigorous standards of population health models now accepted as best practice in other health areas. This paper describes the outcomes from the application of a health promotion model to the development, implementation and evaluation of a community awareness campaign designed to improve mental health literacy and early help seeking amongst young people. Method: The Compass Strategy was implemented in the western metropolitan Melbourne and Barwon regions of Victoria, Australia. The Precede-Proceed Model guided the population assessment, campaign strategy development and evaluation. The campaign included the use of multimedia, a website, and an information telephone service. Multiple levels of evaluation were conducted. This included a cross-sectional telephone survey of mental health literacy undertaken before and after 14 months of the campaign using a quasi-experimental design. Randomly selected independent samples of 600 young people aged 12 - 25 years from the experimental region and another 600 from a comparison region were interviewed at each time point. A series of binary logistic regression analyses were used to measure the association between a range of campaign outcome variables and the predictor variables of region and time. Results: The program was judged to have an impact on the following variables, as indicated by significant region-by-time interaction effects ( p < 0.05): awareness of mental health campaigns, self-identified depression, help for depression sought in the previous year, correct estimate of prevalence of mental health problems, increased awareness of suicide risk, and a reduction in perceived barriers to help seeking. These effects may be underestimated because media distribution error resulted in a small amount of print material leaking into the comparison region. Conclusion: We believe this is the first study to apply the rigorous standards of a health promotion model including the use of a control region to a mental health population intervention. The program achieved many of its aims despite the relatively short duration and moderate intensity of the campaign.

Development of a DNA-based method for detection and identification of Phytophthora species

Phytophthora diseases cause major losses to agricultural and horticultural production in Australia and worldwide. Most Phytophthora diseases are soilborne and difficult to control, making disease prevention an important component of many disease management strategies. Detection and identification of the causal agent, therefore, is an essential part of effective disease management. This paper describes the development and validation of a DNA-based diagnostic assay that can detect and identify 27 different Phytophthora species. We have designed PCR primers that are specific to the genus Phytophthora. The resulting amplicon after PCR is subjected to digestion by restriction enzymes to yield a specific restriction pattern or fingerprint unique to each species. The restriction patterns are compared with a key comprising restriction patterns of type specimens or representative isolates of 27 different Phytophthora species. A number of fundamental issues, such as genetic diversity within and among species which underpin the development and validation of DNA-based diagnostic assays, are addressed in this paper.

Genotypic variation for cold tolerance during reproductive development in rice: Screening with cold air and cold water

Rice (Oryza sativa L.) plants are susceptible to low temperature during the young microspore stage, which occurs 10-12 days before heading. Low temperature at this time increases spikelet sterility which can cause massive yield loss. Increasing the cold tolerance of cultivars can reduce yield variability in temperate rice-growing environments. Two experiments were conducted in cold air screenings and two were conducted in cold water screenings to examine genotypic variation for cold tolerance, explore flowering traits related to spikelet sterility, and investigate whether the results reflect the level of cold tolerance determined previously in the field. Cold air screenings imposed day/night temperatures of 27 degrees C/13 degrees C, 25 degrees C/15 degrees C and 32 degrees C/25 degrees C following particle initiation until 50% heading, while cold water screenings maintained a relatively constant 19 degrees C. The variation in the commencement of low air temperature treatment did not have an effect on the level of spikelet sterility, indicating that exposure to low temperature during the young microspore stage was more important than the duration of exposure. Spikelet sterility of common cultivars showed a significant correlation between cold air and cold water screenings (r(2) = 0.63, p < 0.01), cold air and field screenings (r(2) = 0.52, p < 0.01) and cold water and field screenings (r(2) = 0.53, p < 0.01), indicating that cold air and cold water can be used for screening genotypes for low temperature tolerance. HSC55, M 103 and Jyoudeki were identified as cold tolerant and Doongara, Sasanishiki and Nipponbare as susceptible cultivars. There was a significant negative relationship between spikelet sterility and both the number of engorged pollen grains per anther and anther area only after imposing cold air and cold water treatment hence, it was concluded that these flowering traits were facultative in nature. In addition, cultivars originating from Australia and California were inefficient at producing filled grain with similar sized anthers containing a similar number of engorged pollen grains as cultivars from other origins. One suggested reason for this poor conversion to filled grain of cultivars from Australia and California may be associated with their small stigma area, particularly when exposed to low temperature conditions. (c) 2006 Elsevier B.V. All rights reserved.

Minimising cold damage during reproductive development among temperate rice genotypes. II. Genotypic variation and flowering traits related to cold tolerance screening

Low temperature during microspore development increases spikelet sterility and reduces grain yield in rice (Oryza sativa L.). The objectives of this study were to determine genotypic variation in spikelet sterility in the field in response to low-temperature and then to examine the use of physio-morphological traits at flowering to screen for cold tolerance. Multiple-sown field experiments were conducted over 4 consecutive years in the rice-growing region of Australia to increase the likelihood of encountering low-temperature during microspore development. More than 50 cultivars of various origins were evaluated, with 7 cultivars common to all 4 years. The average minimum temperature for 9 days during microspore development was used as a covariate in the analysis to compare cultivars at a similar temperature. The low-temperature conditions in Year 4 identified cold-tolerant cultivars such as Hayayuki and HSC55 and susceptible cultivars such as Sasanishiki and Doongara. After low temperature conditions, spikelet sterility was negatively correlated with the number of engorged pollen grains, anther length, anther area, anther width, and stigma area. The number of engorged pollen grains and anther length were found to be facultative traits as their relationships with spikelet sterility were identified only after cold water exposure and did not exist under non-stressed conditions.

Neural progenitor number is regulated by nuclear factor-kappa B p65 and p50 subunit-dependent proliferation rather than cell survival

The number of cells generated by a proliferating stem or precursor cell can be influenced both by proliferation and by the degree of cell death/survival of the progeny generated. In this study, the extent to which cell survival controls progenitor number was examined by comparing the growth characteristics of neurosphere cultures derived from mice lacking genes for the death inducing Bcl-2 homologue Hara Kiri (Hrk), apoptosis-associated protein 1 (Apaf1), or the prosurvival nuclear factor-kappa B (NF kappa B) subunits p65, p50, or c-rel. We found no evidence that Hrk or Apaf1, and by inference the mitochondrial cell death pathway, are involved in regulating the number of neurosphere-derived progeny. However, we identified the p65p50 NF kappa B dimer as being required for the normal growth and expansion of neurosphere cultures. Genetic loss of both p65 and p50 NF kappa B subunits resulted in a reduced number of progeny but an increased proportion of neurons. No effect on cell survival was observed. This suggests that the number and fate of neural progenitor cells are more strongly regulated by cell cycle control than survival. (c) 2005 Wiley-Liss, Inc.

The number, morphology, and distribution of retinal ganglion cells and optic axons in the Australian lungfish Neoceratodus forsteri (Krefft 1870)

Australian lungfish Neoceratodus forsteri may be the closest living relative to the first tetrapods and yet little is known about their retinal ganglion cells. This study reveals that lungfish possess a heterogeneous population of ganglion cells distributed in a horizontal streak across the retinal meridian, which is formed early in development and maintained through to adult stages. The number and complement of both ganglion cells and a population of putative amacrine cells within the ganglion cell layer are examined using retrograde labelling from the optic nerve and transmission electron-microscopic analysis of axons within the optic nerve. At least four types of retinal ganglion cells are present and lie predominantly within a thin ganglion cell layer, although two subpopulations are identified, one within the inner plexiform and the other within the inner nuclear layer. A subpopulation of retinal ganglion cells comprising up to 7% or the total population are significantly larger (> 400 mu m(2)) and are characterized as giant or alpha-like cells. Up to 44% of cells within the retinal ganglion cell layer represent a population of presumed amacrine cells. The optic nerve is heavily fasciculated and the proportion of myelinated axons increases with body length from 17% in subadults to 74% in adults. Spatial resolving power, based on ganglion cell spacing, is low (1.6-1.9 cycles deg(-1), n = 2) and does not significantly increase with growth. This represents the first detailed study of retinal ganglion cells in sarcopterygian fish, and reveals that, despite variation amongst animal groups, trends in ganglion cell density distribution and characteristics of cell types were defined early in vertebrate evolution.

Type III secretion contact-dependent model for the intracellular development of Chlamydia

The medically significant genus Chlamydia is a class of obligate intracellular bacterial pathogens that replicate within vacuoles in host eukaryotic cells termed inclusions. Chlamydia's developmental cycle involves two forms; an infectious extracellular form, known as an elementary body (EB), and a non-infectious form, known as the reticulate body (RB), that replicates inside the vacuoles of the host cells. The RB surface is covered in projections that are in intimate contact with the inclusion membrane. Late in the developmental cycle, these reticulate bodies differentiate into the elementary body form. In this paper, we present a hypothesis for the modulation of these developmental events involving the contact-dependent type III secretion (TTS) system. TTS surface projections mediate intimate contact between the RB and the inclusion membrane. Below a certain number of projections, detachment of the RB provides a signal for late differentiation of RB into EB. We use data and develop a mathematical model investigating this hypothesis. If the hypothesis proves to be accurate, then we have shown that increasing the number of inclusions per host cell will increase the number of infectious progeny EB until some optimal number of inclusions. For more inclusions than this optimum, the infectious yield is reduced because of spatial restrictions. We also predict that a reduction in the number of projections on the surface of the RB (and as early as possible during development) will significantly reduce the burst size of infectious EB particles. Many of the results predicted by the model can be tested experimentally and may lead to the identification of potential targets for drug design. © Society for Mathematical Biology 2006.

Hypertension, glomerular number, and birth weight in African Americans and white subjects in the southeastern United States

Low nephron number has been related to low birth weight and hypertension. In the southeastern United States, the estimated prevalence of chronic kidney disease due to hypertension is five times greater for African Americans than white subjects. This study investigates the relationships between total glomerular number (N-glom), blood pressure, and birth weight in southeastern African Americans and white subjects. Stereological estimates of N-glom were obtained using the physical disector/fractionator technique on autopsy kidneys from 62 African American and 60 white subjects 30-65 years of age. By medical history and recorded blood pressures, 41 African Americans, and 24 white subjects were identified as hypertensive and 21 African Americans and 36 white subjects as normotensive. Mean arterial blood pressure ( MAP) was obtained on 81 and birth weights on 63 subjects. For African Americans, relationships between MAP, N-glom, and birth weight were not significant. For white subjects, they were as follows: MAP and N-glom ( r = -0.4551, P = 0.0047); Nglom and birth weight ( r = 0.5730, P = 0.0022); MAP and birth weight ( r = -0.4228, P = 0.0377). For African Americans, average N-glom of 961 840 +/- 292 750 for normotensive and 867 358 +/- 341 958 for hypertensive patients were not significantly different ( P = 0.285). For white subjects, average N-glom of 923 377 +/- 256 391 for normotensive and 754 319 +/- 329 506 for hypertensive patients were significantly different ( P = 0.03). The data indicate that low nephron number and possibly low birth weight may play a role in the development of hypertension in white subjects but not African Americans.

Festival attendance and the development of social capital

Festivals are emerging worldwide as a growing and vibrant sector of the tourism and leisure industries and are seen to have significant economic, socio-cultural, and political impacts on the destination area and host groups. While there are a number of scholars working on developing valid models to determine the economic impact of festivals on host communities, there are few studies published which focus on the social, cultural, and/or political impacts of festivals and events. The purpose of this paper, therefore, is to determine the degree to which festival attendance facilitates the augmentation of social capital by drawing upon the literature from various disciplines in order to conceptualize the synergy between festivals and social capital. To achieve this, the paper will (1) examine the relevant literature on the key characteristics of ‘festivals’ as distinct from other events and (2) investigate the current uses of the notion of ‘social capital’ within the academic debates in a variety of disciplinary contexts

Evaluation of different models to describe egg and pupal development of Xyleborus fornicatus Eichh. (Coleoptera: Scolytidae), the shot-hole borer of tea in Sri Lanka

Abstract Development data of eggs and pupae of Xyleborus fornicatus Eichh. (Coleoptera: Scolytidae), the shot-hole borer of tea in Sri Lanka, at constant temperatures were used to evaluate a linear and seven nonlinear models for insect development. Model evaluation was based on fit to data (residual sum of squares and coefficient of determination or coefficient of nonlinear regression), number of measurable parameters, the biological value of the fitted coefficients and accuracy in the estimation of thresholds. Of the nonlinear models, the Lactin model fitted experimental data well and along with the linear model, can be used to describe the temperature-dependent development of this species.

Paediatric research in emergency departments international collaborative (PREDICT): First steps towards the development of an Australian and New Zealand research network

Paediatric emergency research is hampered by a number of barriers that can be overcome by a multicentre approach. In 2004, an Australia and New Zealand-based paediatric emergency research network was formed, the Paediatric Research in Emergency Departments International Collaborative (PREDICT). The founding sites include all major tertiary children’s hospital EDs in Australia and New Zealand and a major mixed ED in Australia. PREDICT aims to provide leadership and infrastructure for multicentre research at the highest standard, facilitate collaboration between institutions, health-care providers and researchers and ultimately improve patient outcome. Initial network-wide projects have been determined. The present article describes the development of the network, its structure and future goals.

Low dietary protein during early pregnancy alters bovine placental development

To determine if low dietary protein concentration in the first two trimesters of pregnancy alters placental development, genetically similar heifers from closed herd were fed diets containing different levels of protein in the first and second trimesters of gestation. There were four animals per treatment group, the groups being: L/L = fed a diet containing 7% crude protein (CP) (low protein) in the first and second trimesters; H/H = fed a diet containing 14% (P thigh protein) in the first and second trimesters; L/H = fed low protein in the first trimester and high in the second trimester and vice versa for the H/L group. Low protein diets in the first trimester increased dry cotyledon weight at term. Trophectoderm volume density increased in the H/L and L/H group compared to the L/L and H/H groups. Blood vessel volume and volume density in foetal villi decreased in the H/L and L/H groups compared with the H/H and L/L groups. There was no effect of diet treatment on cotyledon number, diameter or wet weight and no effect on the volume density of connective tissue or fibroblasts in the foetal villi. These results show that a low dietary protein concentration in the first trimester of pregnancy followed by increased protein in the second trimester enhanced placental development. Further, trophectoderm volume was highly correlated with birth weight. Early protein restriction in the pregnant cow may enhance foetal growth in part by stimulating placental growth and function. (C) 1999 Published by Elsevier Science B.V. All rights reserved.

Development of a clinical and echocardiographic score for assigning risk of major events after exercise and dobutamine echocardiograms

The prognostic value of exercise (EXE) and dobutamine echocardiograms (DbE) has been well defined in large studies. However, while risk is determined by both clinical and echo features, no simple means of combining these data has been defined. We sought to combine these data into risk scores. Methods. At 3 expert centers, 7650 pts underwent standard EXE (n=5211) and DbE (w2439) for evaluation of known or suspected CAD and were followed for up to 10 years (mean 5-2) for major events (death or myocardial infarction). A subgroup of 2953 EXE and 1025 DbE pts was randomly selected to develop separate multivariate models for prediction of events. After simplication of each model for clinical use, models were validated in the remaining EXE and DbE pts. ResuI1s. The total number of events was 200 in the EXE and 225 in the DbE pts, of which 58 and 99 events occurred in the respective testing groups. The following regression equations gave equivalent results I” the testing and validation groups for both EXE and DbE; DbE = (Age’O.02) + (DM’l .O) + (Low RPP’0.6) + ([CHF+lschemia+Scar]‘O.7) EXE = ([DM+CHF]‘O.S) + O.S(lschemla #) + l.B(Scar#) - (METS0.19) (where each categorical variable scored 1 when present and 0 when absent, Ischemia# = 1 for l-2 VD. 6 for 3 VD; Scar# = 1 for 1-2 VD, 1.7 for 3 VD). The table summarizes the scores and equivalent outcomes for EXE and DbE. Conclusions. Risk scores based on clinical and EXE or DbE results may be used to quantify the risk of events during follow-up.

Essays on Development Policy and the Political Economy of Conflict

Electoral Rules and Leader Selection: Experimental Evidence from Ugandan Community Groups. Despite a large body of work documenting how electoral systems affect policy outcomes, less is known about their impact on leader selection. We study this by comparing two types of participatory decision making in Ugandan community groups: (i) vote by secret ballot and (ii) open discussion with consensus. Random assignment allows us to estimate the causal impact of the rules on leader types and social service delivery. Vote groups are found to elect leaders more similar to the average member while discussion group leaders are positively selected on socio-economic characteristics. Further, dropout rates are significantly higher in discussion groups, particularly for poorer members. After 3.5 years, vote groups are larger in size and their members save less and get smaller loans. We conclude that the secret ballot vote creates more inclusive groups while open discussion groups favor the already economically successful. Preparing for Genocide: Community Meetings in Rwanda. How do political elites prepare the civilian population for participation in violent conflict? We empirically investigate this question using data from the Rwandan Genocide in 1994. Every Saturday before 1994, Rwandan villagers had to meet to work on community infrastructure. The practice was highly politicized and, according to anecdotal evidence, regularly used by the political elites for spreading propaganda in the years before the genocide. This paper presents the first quantitative evidence of this abuse of the community meetings. To establish causality, we exploit cross-sectional variation in meeting intensity induced by exogenous weather fluctuations. We find that an additional rainy Saturday resulted in a five percent lower civilian participation rate in genocide violence. Selection into Borrowing: Survey Evidence from Uganda. In this paper, I study how changes to the standard credit contract affect loan demand and selection into borrowing, using a representative sample of urban micro enterprises, most with no borrowing experience. Hypothetical loan demand questions are used to test whether firm owners respond to changes in loans' contractual terms and whether take-up varies by firms' risk type and other firm owner characteristics. The results indicate that contracts with lower interest rates and less stringent collateral requirements attract less risky borrowers, suggesting that there is scope for improvement of standard financial contract terms. Credit Contract Structure and Firm Growth: Evidence from a Randomized Control Trial. We study the effects of credit contract structure on firm outcomes among small and medium sized firms. A randomized control trial was carried out to distinguish between some of the key constraints to efficient credit use connected to the firms' business environment and production function, namely (i) backloaded returns (ii) uncertain returns and (iii) indivisible fixed costs. Each firm was followed for the 1-year loan cycle. We describe the experiment and present preliminary results from the first 754 out of 2,340 firms to have completed the loan cycle. Firms offered a grace period have higher profits and higher household income than firms receiving a rebate later on as well as the control group. They also increased the number of paid employees  and reduced the number of unpaid employees, an effect also found among firms that received a cash subsidy at the beginning of the loan cycle. We discuss potential mechanisms behind these effects.