Determining meteorological drivers of salt marsh mosquito peaks in tropical northern Australia

In northern Australia the northern salt marsh mosquito Aedes vigilax is a vector of Ross River virus and is an appreciable pest. A coastal wetland adjacent to Darwin's residential suburbs offers a favorable habitat for Ae. vigilax, and despite vigilant mosquito control efforts, peaks of Ae. vigilax occur in excess of 500/trap/night some months. To improve mosquito control for disease and nuisance biting to nearby residential areas, we sought to investigate meteorological drivers associated with these Ae. vigilax peaks. We fitted a cross‐sectional logistic regression model to weekly counts of female Ae. vigilax mosquitoes collected between July, 1998 and June, 2009 against variables, tide, rainfall, month, year, and larval control. Aedes vigilax peaks were associated with rainfall during the months September to November compared with January, when adjusted for larval control and tide. To maximize mosquito control efficiency, larval control should continue to be implemented after high tides and with increased emphasis on extensive larval hatches triggered by rainfall between September and November each year. This study reiterates the importance of monitoring and evaluating service delivery programs. Using statistical modelling, service providers can obtain solutions to operational problems using routinely collected data. These methods may be applicable in mosquito surveillance or control programs in other areas.     

Implementing Evidence-Based Programs: Lessons Learned From the Field

Evidence-based programs (EBPs) are used in many health promotion efforts to ensure that the intended positive behavioral and health outcomes will be achieved. However, because EBPs are developed and tested in research settings, the contextual elements of real world implementation play an important role in their successful delivery in communities. As an intermediary charged with supporting the translation of research to practice for a statewide teen pregnancy prevention initiative, the ACT for Youth Center of Excellence conducted a mid-course evaluation to identify factors that contribute to the successful implementation of EBPs. The findings indicate that successful implementation involves systematic planning that addresses three critical contextual factors: community readiness, organizational capacity, and setting characteristics. By attending both to factors identified from local practice, and to theory and evidence identified through implementation science, practitioners can strengthen programming and enhance the quality of EBP delivery.     

Intraguild predation by Harmonia axyridis (Coleoptera: Coccinellidae) on native insects in Europe: molecular detection from field samples

Intraguild predation (IGP) is a potential mechanism of negative effects on native species populations by invasive non‐native species such as Harmonia axyridis. Molecular techniques (polymerase chain reaction) were used to probe for the presence of various insect (coccinellid, syrphid and chrysopid) prey DNA in the guts of 177 H. axyridis larvae field‐collected in England, France, Germany, Slovakia and the Czech Republic in 2010. Three of the four target prey species were detected in the guts of H. axyridis at the following rates: Adalia decempunctata 9.6%, Adalia bipunctata 2.8% and Episyrphus balteatus 2.8%. IGP on Chrysoperla carnea was not detected. IGP detection of at least one target species was made in England, France, Slovakia and the Czech Republic, but not in Germany. These results strengthen the evidence that H. axyridis is a very generalist predator. Results are discussed in the context of their ecological significance.     

Activin and GDF11 collaborate in feedback control of neuroepithelial stem cell proliferation and fate

Studies of the olfactory epithelium model system have demonstrated that production of neurons is regulated by negative feedback. Previously, we showed that a locally produced signal, the TGFβ superfamily ligand GDF11, regulates the genesis of olfactory receptor neurons by inhibiting proliferation of the immediate neuronal precursors (INPs) that give rise to them. GDF11 is antagonized by follistatin (FST), which is also produced locally. Here, we show that Fst(-/-) mice exhibit dramatically decreased neurogenesis, a phenotype that can only be partially explained by increased GDF11 activity. Instead, a second FST-binding factor, activin βB (ACTβB), inhibits neurogenesis by a distinct mechanism: whereas GDF11 inhibits expansion of INPs, ACTβB inhibits expansion of stem and early progenitor cells. We present data supporting the concept that these latter cells, previously considered two distinct types, constitute a dynamic stem/progenitor population in which individual cells alternate expression of Sox2 and/or Ascl1. In addition, we demonstrate that interplay between ACTβB and GDF11 determines whether stem/progenitor cells adopt a glial versus neuronal fate. Altogether, the data indicate that the transition between stem cells and committed progenitors is neither sharp nor irreversible and that GDF11, ACTβB and FST are crucial components of a circuit that controls both total cell number and the ratio of neuronal versus glial cells in this system. Thus, our findings demonstrate a close connection between the signals involved in the control of tissue size and those that regulate the proportions of different cell types.     

Sector analysis and predictive modelling reveal iterative shoot-like development in fern fronds

Plants colonized the terrestrial environment over 450 million years ago. Since then, shoot architecture has evolved in response to changing environmental conditions. Our current understanding of the innovations that altered shoot morphology is underpinned by developmental studies in a number of plant groups. However, the least is known about mechanisms that operate in ferns--a key group for understanding the evolution of plant development. Using a novel combination of sector analysis, conditional probability modelling methods and histology, we show that shoots, fronds ('leaves') and pinnae ('leaflets') of the fern Nephrolepis exaltata all develop from single apical initial cells. Shoot initials cleave on three faces to produce a pool of cells from which individual frond apical initials are sequentially specified. Frond initials then cleave in two planes to produce a series of lateral merophyte initials that each contributes a unit of three pinnae to half of the mediolateral frond axis. Notably, this iterative pattern in both shoots and fronds is similar to the developmental process that operates in shoots of other plant groups. Pinnae initials first cleave in two planes to generate lateral marginal initials. The apical and marginal initials then divide in three planes to coordinately generate the determinate pinna. These findings impact both on our understanding of fundamental plant developmental processes and on our perspective of how shoot systems evolved.     

In Salmonella enterica, the sirtuin-dependent protein acylation/deacylation system (SDPADS) maintains energy homeostasis during growth on low concentrations of acetate

Acetyl-coenzyme A synthetase (Acs) activates acetate into acetyl-coenzyme A (Ac-CoA) in most cells. In Salmonella enterica, acs expression and Acs activity are controlled. It is unclear why the sirtuin-dependent protein acylation/deacylation system (SDPADS) controls the activity of Acs. Here we show that, during growth on 10 mM acetate, acs(+) induction in a S. enterica strain that cannot acetylate (i.e. inactivate) Acs leads to growth arrest, a condition that correlates with a drop in energy charge (0.17) in the acetylation-deficient strain, relative to the energy charge in the acetylation-proficient strain (0.71). Growth arrest was caused by elevated Acs activity, a conclusion supported by the isolation of a single-amino-acid variant (Acs(G266S)), whose overproduction did not arrest growth. Acs-dependent depletion of ATP, coupled with the rise in AMP levels, prevented the synthesis of ADP needed to replenish the pool of ATP. Consistent with this idea, overproduction of ADP-forming Ac-CoA-synthesizing systems did not affect the growth behaviour of acetylation-deficient or acetylation-proficient strains. The Acs(G266S) variant was >2 orders of magnitude less efficient than the Acs(WT) enzyme, but still supported growth on 10 mM acetate. This work provides the first evidence that SDPADS function helps cells maintain energy homeostasis during growth on acetate.     

Erythrocyte polyunsaturated fatty acid status, memory, cognition and mood in older adults with mild cognitive impairment and healthy controls

Polyunsaturated fatty acid (PUFA) levels are altered in adults with cognitive decline and also depression. Depression facilitates progression from mild cognitive impairment (MCI) to dementia. We investigated associations between omega-3 (n-3) and omega-6 (n-6) PUFAs and cognition, memory and depression in 50 adults ≥65 years with MCI and 29 controls. Memory, depressive symptoms and erythrocyte PUFAs (% total fatty acids) were assessed. Eicosapentaenoic acid (EPA) was lower in MCI vs controls (.94% vs 1.26%, p<.01); n-6 PUFAs were higher: dihomo-gamma-linolenic acid (1.51% vs 1.32%, p<.01), arachidonic acid (11.54% vs 10.70%, p<.01), n-6 docosapentaenoic acid (DPA:.46% vs.34%, p<.01), and total n-6 PUFA (24.14% vs 23.37%, p<.05). Higher n-6 DPA predicted poorer mental health. Lower n-3 DPA was associated with higher self-reported bodily pain. Adults with MCI had higher depression scores (3.05±.39 vs 1.33±.24, p<.01). Depressive symptoms associated with elevated n-6 PUFA may contribute to cognitive decline in this population.