Influence of historical landscapes, drainage evolution and ecological traits on patterns of genetic diversity in Southeast Asian freshwater snakehead fishes

Snakehead fishes in the family Channidae are obligate freshwater fishes represented by two extant genera, the African Parachannna and the Asian Channa. These species prefer still or slow flowing water bodies, where they are top predators that exercise high levels of parental care, have the ability to breathe air, can tolerate poor water quality, and interestingly, can aestivate or traverse terrestrial habitat in response to seasonal changes in freshwater habitat availability. These attributes suggest that snakehead fishes may possess high dispersal potential, irrespective of the terrestrial barriers that would otherwise constrain the distribution of most freshwater fishes. A number of biogeographical hypotheses have been developed to account for the modern distributions of snakehead fishes across two continents, including ancient vicariance during Gondwanan break-up, or recent colonisation tracking the formation of suitable climatic conditions. Taxonomic uncertainty also surrounds some members of the Channa genus, as geographical distributions for some taxa across southern and Southeast (SE) Asia are very large, and in one case is highly disjunct. The current study adopted a molecular genetics approach to gain an understanding of the evolution of this group of fishes, and in particular how the phylogeography of two Asian species may have been influenced by contemporary versus historical levels of dispersal and vicariance. First, a molecular phylogeny was constructed based on multiple DNA loci and calibrated with fossil evidence to provide a dated chronology of divergence events among extant species, and also within species with widespread geographical distributions. The data provide strong evidence that trans-continental distribution of the Channidae arose as a result of dispersal out of Asia and into Africa in the mid–Eocene. Among Asian Channa, deep divergence among lineages indicates that the Oligocene-Miocene boundary was a time of significant species radiation, potentially associated with historical changes in climate and drainage geomorphology. Mid-Miocene divergence among lineages suggests that a taxonomic revision is warranted for two taxa. Deep intra-specific divergence (~8Mya) was also detected between C. striata lineages that occur sympatrically in the Mekong River Basin. The study then examined the phylogeography and population structure of two major taxa, Channa striata (the chevron snakehead) and the C. micropeltes (the giant snakehead), across SE Asia. Species specific microsatellite loci were developed and used in addition to a mitochondrial DNA marker (Cyt b) to screen neutral genetic variation within and among wild populations. C. striata individuals were sampled across SE Asia (n=988), with the major focus being the Mekong Basin, which is the largest drainage basin in the region. The distributions of two divergent lineages were identified and admixture analysis showed that where they co-occur they are interbreeding, indicating that after long periods of evolution in isolation, divergence has not resulted in reproductive isolation. One lineage is predominantly confined to upland areas of northern Lao PDR to the north of the Khorat Plateau, while the other, which is more closely related to individuals from southern India, has a widespread distribution across mainland SE Asian and Sumatra. The phylogeographical pattern recovered is associated with past river networks, and high diversity and divergence among all populations sampled reveal that contemporary dispersal is very low for this taxon, even where populations occur in contiguous freshwater habitats. C. micropeltes (n=280) were also sampled from across the Mekong River Basin, focusing on the lower basin where it constitutes an important wild fishery resource. In comparison with C. striata, allelic diversity and genetic divergence among populations were extremely low, suggesting very recent colonisation of the greater Mekong region. Populations were significantly structured into at least three discrete populations in the lower Mekong. Results of this study have implications for establishing effective conservation plans for managing both species, that represent economically important wild fishery resources for the region. For C. micropeltes, it is likely that a single fisheries stock in the Tonle Sap Great Lake is being exploited by multiple fisheries operations, and future management initiatives for this species in this region will need to account for this. For C. striata, conservation of natural levels of genetic variation will require management initiatives designed to promote population persistence at very localised spatial scales, as the high level of population structuring uncovered for this species indicates that significant unique diversity is present at this fine spatial scale.

Intake of isoflavone and lignan phytoestrogens and associated demographic and lifestyle factors in older Australian women

The purpose was to determine intake of phytoestrogens in a sample of older Australian women, and to investigate associated lifestyle factors. Subjects were an age-stratified sample of 511 women aged 40-80 y, randomly selected from the electoral roll and participating in the Longitudinal Assessment of Ageing in Women at the Royal Brisbane and Women’s Hospital. A cross-sectional study was conducted to assess isoflavone and lignan intake over the past month from food and supplements using a 112-item phytoestrogen frequency questionnaire. Data were also collected on nutrient intakes, physical activity, smoking, alcohol, non-prescription supplements, hormone therapy, education and occupation. Logistic regression was used to evaluate associations between demographic and lifestyle variables and soy/linseed consumption while controlling for age. Isoflavone intakes were significantly higher in the younger compared to older age groups (p<0.001); there were no age-related differences in lignan intake. Forty-five percent of women consumed at least one serve of a soy and/or linseed item and were defined as a soy/linseed consumer. Median (range) intakes by consumers for isoflavones and lignans (3.9 (0-172) mg/d and 2.4 (0.1-33) mg/d) were higher than intakes by non-consumers (0.004 (0-2.6) mg/d and 1.57 (0.44-4.7) mg/d), respectively (p<0.001). Consumers had higher intakes of dietary fibre (p=0.003), energy (p=0.04) and polyunsaturated fat (p=0.004), and higher levels of physical activity (p=0.006), socio-economic position (p<0.001), education (p<0.001) and supplement use (p<0.001). Women who consumed soy or linseed foods differed in lifestyle and demographic characteristics suggesting these factors should be considered when investigating associations with chronic disease outcomes.

Phylogeographic reconstruction of a bacterial species with high levels of lateral gene transfer

Background Phylogeographic reconstruction of some bacterial populations is hindered by low diversity coupled with high levels of lateral gene transfer. A comparison of recombination levels and diversity at seven housekeeping genes for eleven bacterial species, most of which are commonly cited as having high levels of lateral gene transfer shows that the relative contributions of homologous recombination versus mutation for Burkholderia pseudomallei is over two times higher than for Streptococcus pneumoniae and is thus the highest value yet reported in bacteria. Despite the potential for homologous recombination to increase diversity, B. pseudomallei exhibits a relative lack of diversity at these loci. In these situations, whole genome genotyping of orthologous shared single nucleotide polymorphism loci, discovered using next generation sequencing technologies, can provide very large data sets capable of estimating core phylogenetic relationships. We compared and searched 43 whole genome sequences of B. pseudomallei and its closest relatives for single nucleotide polymorphisms in orthologous shared regions to use in phylogenetic reconstruction. Results Bayesian phylogenetic analyses of >14,000 single nucleotide polymorphisms yielded completely resolved trees for these 43 strains with high levels of statistical support. These results enable a better understanding of a separate analysis of population differentiation among >1,700 B. pseudomallei isolates as defined by sequence data from seven housekeeping genes. We analyzed this larger data set for population structure and allele sharing that can be attributed to lateral gene transfer. Our results suggest that despite an almost panmictic population, we can detect two distinct populations of B. pseudomallei that conform to biogeographic patterns found in many plant and animal species. That is, separation along Wallace's Line, a biogeographic boundary between Southeast Asia and Australia. Conclusion We describe an Australian origin for B. pseudomallei, characterized by a single introduction event into Southeast Asia during a recent glacial period, and variable levels of lateral gene transfer within populations. These patterns provide insights into mechanisms of genetic diversification in B. pseudomallei and its closest relatives, and provide a framework for integrating the traditionally separate fields of population genetics and phylogenetics for other bacterial species with high levels of lateral gene transfer.

Elevated plasma fibronectin levels associated with venous thromboembolism

Elevated plasma fibronectin levels occur in various clinical states including arterial disease. Increasing evidence suggests that atherothrombosis and venous thromboembolism (VTE) share common risk factors. To assess the hypothesis that high plasma fibronectin levels are associated with VTE, we compared plasma fibronectin levels in the Scripps Venous Thrombosis Registry for 113 VTE cases vs. age and sex matched controls. VTE cases had significantly higher mean fibronectin concentration compared to controls (127% vs. 103%, p<0.0001); the difference was greater for idiopathic VTE cases compared to secondary VTE cases (133% vs. 120%, respectively). Using a cut-off of >90% of the control values, the odds ratio (OR) for association of VTE for fibronectin plasma levels above the 90th percentile were 9.37 (95% CI 2.73-32.2; p<0.001) and this OR remained significant after adjustment for sex, age, body mass index (BMI), factor V Leiden and prothrombin nt20210A (OR 7.60, 95% CI 2.14-27.0; p=0.002). In particular, the OR was statistically significant for idiopathic VTE before and after these statistical adjustments. For the total male cohort, the OR was significant before and after statistical adjustments and was not significant for the total female cohort. In summary, our results suggest that elevated plasma fibronectin levels are associated with VTE especially in males, and extend the potential association between biomarkers and risk factors for arterial atherothrombosis and VTE. © 2008 Schattauer GmbH.

Is adiponectin implicated in venous thromboembolism?

In summary, these results imply that the relationship of adiponectin with lipoproteins is more complex than previously predicted using other methods of lipoprotein fractionation. Higher correlation of adiponectin was shown with large lipoprotein particle size, independent of the apolipoprotein content. Given the small population studied, we could not assess the influence of mild risk factors for venous thrombosis, such as obesity, on the analysis of the results. Thus, we can only state that adiponectin levels appear not to be a strong risk factor for VTE. It is possible that adiponectin deficiency may contribute indirectly to the etiology of VTE by enhancing the inflammatory state. © 2006 International Society on Thrombosis and Haemostasis.

Oral intake and serum levels of ascorbic acid in continuous ambulatory peritoneal dialysis patients

Oral intake of ascorbic acid is essential for optimum health in human beings. Continuous ambulatory peritoneal dialysis (CAPD) patients have an increased need for ascorbic acid, because of increased loss through dialysate, reduced intake owing to nausea and loss of appetite, and increased oxidative stress. However, optimum intake is still controversial. We studied 50 clinically stable patients to determine the relationship between oral ascorbic acid intake and serum ascorbic acid (SAA) level. Total oral intake ranged from 28 mg daily to 412 mg daily. Only one patient had an oral intake of ascorbic acid below 60 mg per day. The SAA levels ranged from 1 mg/L to 36.17 mg/L. Although a strong correlation existed between intake and SAA (p < 0.001, R2 = 0.47), the variation in SAA at any given intake level was wide. Of the studied patients, 62% had an SAA < 8.7 mg/L, 40% had an SAA < 5.1 mg/L (below the level in a healthy population), and 12% had a level below 2 mg/L (scorbutic). None of the patients demonstrated clinical manifestations of scurvy. Our results show that, in CAPD patients, ascorbic acid deficiency can be reliably detected only with SAA measurements, and oral intake may influence SAA level. To maintain ascorbic acid in the normal range for healthy adults, daily oral intake needs to be increased above the U.S. recommended dietary allowance to 80-140 mg.

Parental bonding and alexithymia : a meta-analysis

Aim: The primary purpose of this meta-analysis was to explore, clarify and report the strength of the relationship between alexithymia, as measured by the Toronto Alexithymia Scale (TAS-20), and parenting style as measured by the Parental Bonding Instrument (PBI). Methods: Web of Science, PsycInfo, PubMed and ProQuest: Dissertations and Theses searches were undertaken, yielding nine samples with sufficient data to be included in the meta-analysis. Results: Evidence indicated moderate to strong relationships between maternal care and alexithymia, and between maternal care and two of the three TAS-20 alexithymia facets (Difficulties Describing Feelings and Difficulties Identifying Feelings, but not Externally Oriented Thinking). Moderate relationships were observed for both maternal- and paternal-overprotection and alexithymia respectively, and for overprotection (both maternal and paternal) and Difficulties Describing Feelings. Conclusion: This study is the first meta-analysis of the relationship between parenting styles and alexithymia, and findings confirm an especially strong association between maternal care and key elements of alexithymia. This review highlights the issues that still remain to be addressed in exploring the link between parenting style and alexithymia.

Parent decisions regarding paid work and care of the child

Australia has witnessed a continual increase in maternal employment over the past two decades, which has placed focus on child care- its effects on the child and on early childhood education and care policy and provision. The engagement of women in the paid workforce contributes to national economic development, and is recognised in government policy incentives such as cash subsidies and tax relief for child care fees. These incentives are targeted towards mothers, to encourage them to engage in paid work. Making a contribution to the family’s economy and to a mother’s economic self sufficiency are two key drivers for women’s engagement in satisfying paid work. Many women also seek to maintain a personal investment in the development of their career, simultaneously ensuring that the child is experiencing suitable care. Policies that support women’s choices for satisfying workforce engagement and care arrangements are prudent for ensuring productivity of the economy as well as for enhancing the wellbeing of parents and children (OECD, 2007). Policies that provide family friendly employment arrangements, paid parental leave, and child care support, directly affect maternal employment decisions. Availability of family friendly employment policies is viewed as one way to not only promote gender equity in employment opportunities but also support the wellbeing of children and families (OECD, 2007). Yet there are not comprehensive and coherent policies on work and family in Australia. Australia is due to implement its first paid parental leave scheme in January, 2011. At the time of the data collection of this research, June 2007 to December 2008, Australia had no statutory provision for paid parental leave. To date, most research has focused on the consequences of paid work and care decisions made by women. Far less is known about the processes of decision-making and reasons underlying women’s choices. Investigation of what is most salient for women as they make decisions regarding engagement in paid work, and care for their child is important in order to inform policy and practices related to parental leave, family friendly employment and care for the child. This prospective longitudinal research was of 124 Australian expectant first-time mothers who completed questionnaires in their third trimester of pregnancy, and again at six and twelve months postpartum. First-time expectant mothers' decisions regarding engaging in paid work and selecting care for their child represent those of a group who are invested in motherhood and have usually had direct experience of engaging in paid work. They therefore provide an important insight into society’s idealised views about motherhood and the emotional and social uncertainty of making personal decisions where the consequences of such decisions are unknown. These decisions reflect public beliefs about the role of women in contributing to the country’s productivity and decisions about providing for the economic and emotional care needs of their family. As so little is known about the reasoning and processes of decision-making of women’s choices regarding paid work and care of the child this research was designed to capture expectant first-time mother’s preferred options for engaging in paid work and the care of their child, and investigate their actual decisions made at six and 12 months postpartum. To capture preferred options, decisions and outcomes of decisions regarding paid work and care of the child a prospective longitudinal research design was utilised. This design had three important components that addressed key limitations in the extant literature. First the research commenced in pregnancy in order to investigate preferences and beliefs about paid work and care and to examine baseline data that may influence decisions made as the women returned to paid work. Second the research involved longitudinal tracking from the antenatal time point to six and 12 months postpartum in order to identify the influences on decisions made. Third the research measured outcomes of the decisions made at each time point. This research examined the intentions, preferences, beliefs, influences, and outcomes of the decisions about engagement in paid work and choice of care. The analyses examined factors predicting return to paid work, the timing of return and extent of engagement in paid work; the care for the child; satisfaction with paid work; satisfaction with care for the child, motherhood and fulfilment; and maternal wellbeing at six and 12 months postpartum. The factors of interest were both rational/economic (availability and extent of paid and unpaid maternity leave; flexible work patterns) and emotional/affective (career satisfaction, investment in motherhood, and concern with quality of care for the child). Results indicated a group preference, and realisation for, return to paid work within the first year after the birth of a child but with reduction in hours to part-time. Most women saw paid work not only as a source of income but also as source of personal satisfaction. There were four key themes arising from this research. First, the women strived to feel emotionally secure when deciding about engaging in paid work and care of the child. To achieve emotional security women made their decisions for paid work and care of the child differently. A woman’s decision for maternal employment is a function of her personal beliefs, preferences and context regarding paid work and care of the child. She adjusts her established work identity with her new identity as a mother. The second key theme from this research is that the women made their decisions for maternal employment in response to their personal context and there were different levels of opportunities between the women’s choices. There is inequity of entitlement regarding work conditions associated with a woman’s education level. This has implications for the woman’s engagement in paid work, and her child’s health and wellbeing. The third key theme is that the quality of the child’s care mattered to the women in the research. They preferred care provided by parents and/or relatives more than any other types of care. The fourth key theme identified that satisfaction and wellbeing outcomes experienced as a result of maternal employment decisions were a complex interaction between multiple factors that change across time with the ongoing development of the mother’s identity, and the development of the child. The implications for policy within Australia are that the employment of mothers in the workforce necessitates that non-parental care becomes a public concern, where there is universal access to good quality affordable care for every child, not just for those who can afford it. This is equitable and represents real choice while supporting the rights of the child (Thorpe, Cloney & Tayler, 2010), protecting and promoting the public interest (Cleveland & Krashinsky, 2010). Children’s health and wellbeing will be supported (Moore & Oberklaid, 2010) while children are in non-parental care, and they will be exposed to environments and experiences that support their learning and development. The significant design of the research enabled the trajectories of first-time expectant women to be tracked from the antenatal point to 12 months postpartum. But there were limitations: the small sample size, the over-representation of the sample being highly educated and the nature of a longitudinal research that is set within the economic, social and political context at that time. These limitations are discussed in relation to suggestions for future research.

Association of inducible nitric oxide synthase with asthma severity, total serum immunoglobulin E and blood eosinophil levels

Background Nitric oxide is released by immune, epithelial and endothelial cells, and plays an important part in the pathophysiology of asthma. Objective To investigate the association of inducible nitric oxide synthases (iNOS) gene repeat polymorphisms with asthma. Methods 230 families with asthma (842 individuals) were recruited to identify and establish the genetic association of iNOS repeats with asthma and associated phenotypes. Serum nitric oxide levels in selected individuals were measured and correlated with specific genotypes. Multiple logistic regression analysis was performed to determine the effect of age and sex. Results A total of four repeats—a (CCTTT)n promoter repeat, a novel intron 2 (GT)n repeat (BV680047), an intron 4 (GT)n repeat (AFM311ZB1) and an intron 5 (CA)n repeat (D17S1878)—were identified and genotyped. A significant transmission distortion to the probands with asthma was seen for allele 3 of the AFM311ZB1 gene (p = 0.006). This allele was also found to be significantly associated with percentage blood eosinophils (p<0.001) and asthma severity (p = 0.04). Moreover, it was functionally correlated with high serum nitric oxide levels (p = 0.006). Similarly, the promoter repeat was found to be associated with serum total immunoglobulin (Ig)E (p = 0.028). Individuals carrying allele 4 of this repeat have high serum IgE (p<0.001) and nitric oxide levels (p = 0.03). Conclusion This is the first study to identify the repeat polymorphisms in the iNOS gene that are associated with severity of asthma and eosinophils. The functional relevance of the associated alleles with serum nitric oxide levels was also shown. Therefore, these results could be valuable in elucidating the role of nitric oxide in asthma pathogenesis.