Extensive public health initiatives drive the elimination of Aedes aegypti (Diptera,Culicidae) from a town in regional Queensland: A case study from Gin Gin,Australia

Aedes aegypti is the primary vector of exotic arboviruses (dengue, chikungunya and Zika) in Australia. Once established across much of Australia, this mosquito species remains prevalent in central and northern Queensland. In 2011, Ae. aegypti was re-discovered in the town of Gin Gin, Queensland, by health authorities during routine larval surveillance. This town is situated on a major highway that provides a distribution pathway into the highly vulnerable and populous region of the state where the species was once common. Following the detection, larval habitat and adult control activities were conducted as a public health intervention to eliminate the Ae. aegypti population and reduce the risk of exotic disease transmission. Importantly, genetic analysis revealed a homogenous cluster and small effective population vulnerable to an elimination strategy. By 2015, adult surveillance revealed the population had expanded throughout the centre of the town. In response, a collaboration between research agencies and local stakeholders activated a second control program in 2016 that included extensive community engagement, enhanced entomologic surveillance and vector control activities including the targeting of key containers, such as unsealed rainwater tanks. Here we describe a model of the public health intervention which successfully reduced the Ae. aegypti population below detection thresholds, using source reduction, insecticides and novel, intensive genetic surveillance methods. This outcome has important implications for future elimination work in small towns in regions sub-optimal for Ae. aegypti presence and reinforces the longstanding benefits of a partnership model for public health-based interventions for invasive urban mosquito species.     

Stomatal conductance and not stomatal density determines the long-term reduction in leaf transpiration of poplar in elevated CO<Subscript>2</Subscript>

Using a free-air CO₂ enrichment (FACE) experiment, poplar trees (Populus × euramericana clone I214) were exposed to either ambient or elevated [CO₂] from planting, for a 5-year period during canopy development, closure, coppice and re-growth. In each year, measurements were taken of stomatal density (SD, number mm⁻²) and stomatal index (SI, the proportion of epidermal cells forming stomata). In year 5, measurements were also taken of leaf stomatal conductance (g _s, μmol m⁻² s⁻¹), photosynthetic CO₂ fixation (A, mmol m⁻² s⁻¹), instantaneous water-use efficiency (A/E) and the ratio of intercellular to atmospheric CO₂ (C_i:C_a). Elevated [CO₂] caused reductions in SI in the first year, and in SD in the first 2 years, when the canopy was largely open. In following years, when the canopy had closed, elevated [CO₂] had no detectable effects on stomatal numbers or index. In contrast, even after 5 years of exposure to elevated [CO₂], g _s was reduced, A/E was stimulated, and C_i:C_a was reduced relative to ambient [CO₂]. These outcomes from the long-term realistic field conditions of this forest FACE experiment suggest that stomatal numbers (SD and SI) had no role in determining the improved instantaneous leaf-level efficiency of water use under elevated [CO₂]. We propose that altered cuticular development during canopy closure may partially explain the changing response of stomata to elevated [CO₂], although the mechanism for this remains obscure.     

An Early Devonian arthropod fauna from the Windyfield cherts, Aberdeenshire, Scotland

New terrestrial and freshwater arthropods are described from the Windyfield cherts, a suite of silicified sinters deposited 700m north‐east of the Rhynie cherts and part of the same Early Devonian hot‐spring complex. The diverse assemblage consists of Heterocrania rhyniensis (Hirst and Maulik, 1926a), here recognized as a euthycarcinoid; scutigeromorph centipede material assigned to Crussolum sp.; the crustacean Lepidocaris; trigonotarbid arachnids; a new arthropod of myriapod affinities named Leverhulmia mariae gen. et sp. nov.; and the distinctively ornamented arthropod cuticle of Rhynimonstrum dunlopi gen. et sp. nov. The Leverhulmia animal preserves gut content identifying it as an early terrestrial detritivore. Abundant coprolites of similar composition and morphology to the gut contents of the euthycarcinoid crowd the matrix. Chert texture, faunal associations, and study of modern analogues strongly suggest that the terrestrial arthropods were ubiquitous Early Devonian forms with no particular special adaptation to localized conditions around the terrestrial hot‐spring vents. The aquatic arthropods represent biota from ephemeral cool‐water pools in the vicinity of the hot‐spring vents.     

A New Jawless Vertebrate from the Middle Devonian of Scotland

A new jawless vertebrate, Cornovichthys blaauweni gen. et sp. nov., is described from a single complete specimen from the Achanarras fish bed at Achanarras Quarry in Caithness, northern Scotland. The Achanarras fish bed consists of lacustrine laminites and was deposited in a major deep-water phase of the Orcadian lake during the deposition of the cyclic Caithness Flagstone Group. The Achanarras fish bed is of Middle Devonian (Eifelian) age. The new animal compares closely with Euphanerops, one ofthe Frasnian 'anaspids' (Hyperoartii) of the Escuminac Formation at Miguasha, Quebec, Canada.     

Vesicles from peptidic side-chain polymers synthesized by atom transfer radical polymerization

Block copolymers can adopt a wide range of morphologies in dilute aqueous solution. There is a significant amount of interest in the use of block copolymer vesicles for a number of applications. We show that a series of oligo(valine) and oligo(phenylalanine) peptides coupled to a methacrylic group can be prepared by conventional peptide coupling techniques. These can be successfully polymerized by atom transfer radical polymerization (ATRP) in hexafluoroisopropanol (HFIP) giving access to poly(ethylene oxide)- b-poly(side-chain peptides). Many of these polymers self-assemble to form vesicles using an organic to aqueous solvent exchange. One example with a divaline hydrophobic block gives a mixture of toroids and vesicles. Circular dichroism demonstrates that secondary structuring is observed in the hydrophobic region of the vesicle walls for the valine side-chain containing polymers.     

Estrous cycle-regulated expression of CYP1B1 mRNA in the rat ovary

CYP1B1, a member of the cytochrome p450 superfamily, is expressed constitutively in the steroidogenic tissues of mammals and is inducible by peptide hormones, cAMP and aromatic hydrocarbon receptor (AHR) ligands. The mechanism of induction of this cytochrome p450 is similar to that for CYP1A1, i.e. through the aromatic hydrocarbon receptor (AHR) signaling pathway. We have recently reported that CYP1B1, but not CYP1A1, is expressed in rat granulosa cells (GC) in the absence of any external stimulus. The induction of CYP1B1 mRNA in rat GC by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in vitro was followed by an increase in AHR and estrogen receptor (ER-beta) RNA levels. Estrous cycle-dependent expression of AHR, AHR-nuclear translocator (ARNT) and ER-mRNAs in the rat ovary was reported. We suggest that CYP1B1 may play a major role in the regulation of rat ovarian function/cycle but until now this has been unexplored experimentally. The present study was therefore aimed at examining the expression of CYP1A1, CYP1B1 and ER-mRNA in rat ovarian tissues throughout the estrous cycle to establish any correlation in the expressions of these mRNAs in rat ovary. Total RNA was extracted from the ovary and liver of cycling adult rats and the mRNAs were analyzed using relative RT-PCR with gene-specific primers for the target mRNA and for RPL 19 or S16 primers as an internal control. The results indicated that in the ovary, CYP1B1 mRNA increased significantly on the evening of proestrus and dramatically decreased on the morning of estrus, while ER-mRNA remained unaltered throughout the estrous cycle. CYP1A1 mRNA in the ovary and both CYP1A1 and CYP1B1 mRNAs in the liver were undetectable. That the sudden decrease of ovarian CYP1B1 mRNA on the morning of estrus was not an effect of the LH surge was verified in vitro using our short-term GC culture model. GC prepared from rats super-stimulated with equine chorionic gonadotropin (eCG) were cultured for 6 h with or without LH and TCDD. It was observed that both CYP1A1 and CYP1B1 mRNAs were induced by TCDD with no apparent effect of LH. It is suggested that the high level of CYP1B1 mRNA expression on the evening of proestrus in rat ovary might be involved in metabolism of estrogens to catecholestrogen (a known effect of CYP1B1), and that expression is unaffected in GC by LH.     

Ionizing Radiation as an Industrial Health Problem

Ionizing radiation, first as x-rays, later in natural form, was discovered in Europe in the late 1890''s. Immediate practical uses were found for these discoveries, particularly in medicine. Unfortunately, because of the crude early equipment and ignorance of the harmful effects of radiation, many people were injured, some fatally. Because of these experiences, committees and regulatory bodies were set up to study the problem. These have built up an impressive fund of knowledge useful in radiation protection.With the recent development of the peaceful uses of atomic energy, sources of radioactivity have appeared cheaply and in abundance. A rapidly growing number are finding industrial application. Because of their potential risk to humans, the industrial physician must acquire new knowledge and skills so that he may give proper guidance in this new realm of preventive medicine.The Radiation Protection Program of one such industry, the Hydro-Electric Power Commission of Ontario, is summarized.     

Two hepcidin-like antimicrobial peptides in Barramundi Lates calcarifer exhibit differing tissue tropism and are induced in response to lipopolysaccharide

Genes encoding two hepcidin-like antimicrobial peptides were discovered in Barramundi, Lates calcarifer (barramundi, Giant sea perch). Analysis of the coding regions indicated that genes for each hepcidin comprised 3 exons and 2 introns. The deduced amino acid sequences for each molecule resulted in a protein comprising a signal sequence of 24 aa in each case, coupled to a prepropeptide of 75 aa for hepcidin 1 and 78 aa for hepcidin 2. A cleavage site was identified in each prepropetide at amino acid 64 with the cleavage motif--QKR/QS--resulting in mature peptides of 25 and 28 amino acids respectively. Each mature peptide contained 8 conserved cysteine residues and 3 dimensional modeling predicted a β-hairpin and β-sheet structure characteristic of human Liver Expressed Antimicrobial Peptide (LEAP). Analysis of the deduced amino acid sequences by BLAST with phylogenetic supported indicated that hepcidin 1 was a HAMP1-type peptide closely related to hepcidins identified in other Perciformes (Micropterus and Pseudosciaena), whilst hepcidin 2 was a HAMP2-type peptide most similar to a hepcidin previously identified in black rock fish (Sebastes schlegeli). Both hepcidin genes were inducible in barramundi following intraperitoneal injection with lipopolysaccharide, with elevated expression detected in liver and head kidney 3 h post IP injection for hepcidin 1 and in liver only for hepcidin 2. The elevated expression was transient with return to normal levels within 24-48 h. No significant expression of either peptide was detected in spleen, skin or gill following IP injection with LPS.     

Use the Protonmotive Force: Mitochondrial Uncoupling and Reactive Oxygen Species

Mitochondrial respiration results in an electrochemical proton gradient, or protonmotive force (pmf), across the mitochondrial inner membrane. The pmf is a form of potential energy consisting of charge (?ψ_m) and chemical (?pH) components, that together drive ATP production. In a process called uncoupling, proton leak into the mitochondrial matrix independent of ATP production dissipates the pmf and energy is lost as heat. Other events can directly dissipate the pmf independent of ATP production as well, such as chemical exposure or mechanisms involving regulated mitochondrial membrane electrolyte transport. Uncoupling has defined roles in metabolic plasticity and can be linked through signal transduction to physiologic events. In the latter case, the pmf impacts mitochondrial reactive oxygen species (ROS) production. Although capable of molecular damage, ROS also have signaling properties that depend on the timing, location, and quantity of their production. In this review, we provide a general overview of mitochondrial ROS production, mechanisms of uncoupling, and how these work in tandem to affect physiology and pathologies, including obesity, cardiovascular disease, and immunity. Overall, we highlight that isolated bioenergetic models—mitochondria and cells—only partially recapitulate the complex link between the pmf and ROS signaling that occurs in vivo.