Drying and re-wetting of organic wetland sediments: Biogeochemistry and implications for wetland management

In the past decade, increasing instances of eutrophication and acidification of wetlands on the Swan Coastal Plain (SCP), Western Australia, and particularly on the Gnangara groundwater mound, have coincided with gradually decreasing ground- and surface water levels. The processes involved in determining whether a wetland will acidify or become eutrophic (or both) as a result of drawdown are still poorly understood, especially on the SCP where there are strong links between wetland water quality and underlying geomorphology. For instance, many of the wetlands located on the wellbuffered geomorphic unit called the Spearwood dunes are eutrophic due to high nutrient loads, and drying appears to exacerbate this. On the other hand, many of the wetlands on the leached and poorly buffered geomorphic unit called the Bassendean dunes also have relatively high nutrient inputs but are not eutrophic, and drying appears to cause acidification. However, an increasing number of wetlands on the Spearwood dunes are now also becoming acidified due to lowered groundwater tables

Predation by Gambusia Holbrooki (Girard) (Pisces Poeciliidae) on Tadpoles : Feeding Trials and Microhabitat Utilisation in Two Contrasting Wetlands on the Swan Coastal Plain, Western Australia

Predation by non-native Gambusia spp. (somewhat inappropriately referred to as “Mosquitofish”) has been implicated in the decline of some frog populations overseas and in eastern Australia. Originally introduced to control mosquito larvae, Gambusia holbrooki are now widely distributed and abundant in wetlands of the Swan Coastal Plain (Western Australia). Anecdotal evidence suggests that some frog populations on the Swan Coastal Plain may be declining. Through a series of laboratory feeding trials and a field survey conducted in a permanent and a seasonal wetland on the Swan Coastal Plain, this study investigated whether predation by G. holbrooki has the potential to impact local frog populations. Laboratory feeding trials were carried out with tadpoles/eggs of five local frog species. Larval developmental stages were classed into four broad groups. One experiment involving 20 single predator:prey treatments and 20 controls (prey only) was conducted with each developmental stage group of each tadpole species. All tadpole species with which feeding trials were conducted were either consumed or injured by G. holbrooki. Hierarchical log-linear analysis revealed that there were significant associations between larval developmental stage and survival, and between tadpole species and survival. However, there was no association between tadpole species and the number of tadpoles consumed by G. holbrooki. The smallest tadpoles (hatchlings) had the highest mortality and consumption rate, indicating gape-limited predation by G. holbrooki. It was therefore concluded that differences in survival and consumption rate between species and between larval developmental stages are more likely to be related to tadpole size than to palatability. The field survey examined temporal and spatial associations in microhabitat use by G. holbrooki and local tadpole species. A total of 103 4x4m quadrats were sampled at Lake Jandabup and Lake Gwelup on three sampling occasions. Major habitat types, characterised by vegetation community structure, were identified using UPGMA classification, and faunal abundances within each habitat type and each sampling occasion were compared. Sites were then classified and ordinated based on faunal assemblages in order to find patterns in their spatial and temporal distribution. Principal axis correlation was used to find the best linear correlation of various environmental variables with the ordination of sites. The results of these analyses indicate considerable microhabitat overlap, and thus a potential for interactions to occur, between G. holbrooki and some local tadpole species. Scenarios of potential interactions in the field are discussed in view of the combined results of both research components, as well as in consideration of other influencing factors which were not directly investigated as part of this study. It was concluded that there is a potential for the direct and/or indirect effects of predation by G. holbrooki on tadpoles to impact local frog populations

Identification and pathogenicity of a natural reassortant between a very virulent serotype 1 infectious bursal disease virus (IBDV) and a serotype 2 IBDV

AbstractInfectious bursal disease virus (IBDV) causes an economically important, immunosuppressive disease in chickens. There are two serotypes of the virus that contain a bi-segmented double-stranded RNA genome. In December 2008, the first very virulent (vv)IBDV was identified in California, USA and in 2009 we isolated reassortant viruses in two different locations. Genome segment A of these reassortants was typical of vvIBDV serotype 1 but genome segment B was most similar to IBDV serotype 2. The CA-K785 reassortant caused 20% mortality in chickens but no morbidity or mortality in commercial turkey poults despite being infectious. There have been previous reports of natural reassortants between vvIBDV and other serotype 1 strains, but a natural reassortant between IBDV serotypes 1 and 2 has not been described. The apparent reassorting of California vvIBDV with an endemic serotype 2 virus indicates a common host and suggests vvIBDV may have entered California earlier than originally thought

Need for high-resolution genetic analysis in iPSC: results and lessons from the ForIPS consortium

Genetic integrity of induced pluripotent stem cells (iPSCs) is essential for their validity as disease models and for potential therapeutic use. We describe the comprehensive analysis in the ForIPS consortium: an iPSC collection from donors with neurological diseases and healthy controls. Characterization included pluripotency confirmation, fingerprinting, conventional and molecular karyotyping in all lines. In the majority, somatic copy number variants (CNVs) were identified. A subset with available matched donor DNA was selected for comparative exome sequencing. We identified single nucleotide variants (SNVs) at different allelic frequencies in each clone with high variability in mutational load. Low frequencies of variants in parental fibroblasts highlight the importance of germline samples. Somatic variant number was independent from reprogramming, cell type and passage. Comparison with disease genes and prediction scores suggest biological relevance for some variants. We show that high-throughput sequencing has value beyond SNV detection and the requirement to individually evaluate each clone

Genetic Evidence of Serum Phosphate-Independent Functions of FGF-23 on Bone

Maintenance of physiologic phosphate balance is of crucial biological importance, as it is fundamental to cellular function, energy metabolism, and skeletal mineralization. Fibroblast growth factor-23 (FGF-23) is a master regulator of phosphate homeostasis, but the molecular mechanism of such regulation is not yet completely understood. Targeted disruption of the Fgf-23 gene in mice (Fgf-23−/−) elicits hyperphosphatemia, and an increase in renal sodium/phosphate co-transporter 2a (NaPi2a) protein abundance. To elucidate the pathophysiological role of augmented renal proximal tubular expression of NaPi2a in Fgf-23−/− mice and to examine serum phosphate–independent functions of Fgf23 in bone, we generated a new mouse line deficient in both Fgf-23 and NaPi2a genes, and determined the effect of genomic ablation of NaPi2a from Fgf-23−/− mice on phosphate homeostasis and skeletal mineralization. Fgf-23−/−/NaPi2a−/− double mutant mice are viable and exhibit normal physical activities when compared to Fgf-23−/− animals. Biochemical analyses show that ablation of NaPi2a from Fgf-23−/− mice reversed hyperphosphatemia to hypophosphatemia by 6 weeks of age. Surprisingly, despite the complete reversal of serum phosphate levels in Fgf-23−/−/NaPi2a−/−, their skeletal phenotype still resembles the one of Fgf23−/− animals. The results of this study provide the first genetic evidence of an in vivo pathologic role of NaPi2a in regulating abnormal phosphate homeostasis in Fgf-23−/− mice by deletion of both NaPi2a and Fgf-23 genes in the same animal. The persistence of the skeletal anomalies in double mutants suggests that Fgf-23 affects bone mineralization independently of systemic phosphate homeostasis. Finally, our data support (1) that regulation of phosphate homeostasis is a systemic effect of Fgf-23, while (2) skeletal mineralization and chondrocyte differentiation appear to be effects of Fgf-23 that are independent of phosphate homeostasis

Local Response in Health Emergencies: Key Considerations for Addressing the COVID-19 Pandemic in Informal Urban Settlements

This paper highlights the major challenges and considerations for addressing COVID-19 in informal settlements. It discusses what is known about vulnerabilities and how to support local protective action. There is heightened concern about informal urban settlements because of the combination of population density and inadequate access to water and sanitation, which makes standard advice about social distancing and washing hands implausible. There are further challenges to do with the lack of reliable data and the social, political and economic contexts in each setting that will influence vulnerability and possibilities for action. The potential health impacts of COVID-19 are immense in informal settlements, but if control measures are poorly executed these could also have severe negative impacts. Public health interventions must be balanced with social and economic interventions, especially in relation to the informal economy upon which many poor urban residents depend. Local residents, leaders and communitybased groups must be engaged and resourced to develop locally appropriate control strategies, in partnership with local governments and authorities. Historically, informal settlements and their residents have been stigmatized, blamed, and subjected to rules and regulations that are unaffordable or unfeasible to adhere to. Responses to COVID-19 should not repeat these mistakes. Priorities for enabling effective control measures include: collaborating with local residents who have unsurpassed knowledge of relevant spatial and social infrastructures, strengthening coordination with local governments, and investing in improved data for monitoring the response in informal settlements

The genetic architecture of the human cerebral cortex

The cerebral cortex underlies our complex cognitive capabilities, yet little is known about the specific genetic loci that influence human cortical structure. To identify genetic variants that affect cortical structure, we conducted a genome-wide association meta-analysis of brain magnetic resonance imaging data from 51,665 individuals. We analyzed the surface area and average thickness of the whole cortex and 34 regions with known functional specializations. We identified 199 significant loci and found significant enrichment for loci influencing total surface area within regulatory elements that are active during prenatal cortical development, supporting the radial unit hypothesis. Loci that affect regional surface area cluster near genes in Wnt signaling pathways, which influence progenitor expansion and areal identity. Variation in cortical structure is genetically correlated with cognitive function, Parkinson's disease, insomnia, depression, neuroticism, and attention deficit hyperactivity disorder

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

The genetic architecture of the human cerebral cortex

The cerebral cortex underlies our complex cognitive capabilities, yet little is known about the specific genetic loci that influence human cortical structure. To identify genetic variants that affect cortical structure, we conducted a genome-wide association meta-analysis of brain magnetic resonance imaging data from 51,665 individuals. We analyzed the surface area and average thickness of the whole cortex and 34 regions with known functional specializations. We identified 199 significant loci and found significant enrichment for loci influencing total surface area within regulatory elements that are active during prenatal cortical development, supporting the radial unit hypothesis. Loci that affect regional surface area cluster near genes in Wnt signaling pathways, which influence progenitor expansion and areal identity. Variation in cortical structure is genetically correlated with cognitive function, Parkinson's disease, insomnia, depression, neuroticism, and attention deficit hyperactivity disorder