Unravelling the mystery of endemic versus translocated populations of the endangered Australian lungfish (Neoceratodus forsteri)

The Australian lungfish is a primitive and endangered representative of the subclass Dipnoi. The distribution of this species is limited to south-east Queensland, with some populations considered endemic and others possibly descending from translocations in the late nineteenth century shortly after European discovery. Attempts to resolve the historical distribution of this species have met with conflicting results based on descriptive genetic studies. Understanding if all populations are endemic or some are the result of, or influenced by, translocation events, has implications for conservation management. In this work, we analysed the genetic variation at three types of markers (mtDNA genomes, 11 STRs and 5196 nuclear SNPs) using the approximate Bayesian computation (ABC) algorithm to compare several demographic models. We postulated different contributions of Mary River and Burnett River gene pools into the Brisbane River and North Pine River populations, related to documented translocation events. We ran the analysis for each marker type separately, and we also estimated the posterior probabilities of the models combining the markers. Nuclear SNPs have the highest power to correctly identify the true model among the simulated datasets (where the model was known), but different marker types typically provided similar answers. The most supported demographic model able to explain the real dataset implies that an endemic gene pool is still present in the Brisbane and North Pine Rivers and coexists with the gene pools derived from past documented translocation events. These results support the view that ABC modelling can be useful to reconstruct complex historical translocation events with contemporary implications, and will inform ongoing conservation efforts for the endangered and iconic Australian lungfish.

Relaxation of Natural Selection in the Evolution of the Giant Lungfish Genomes

Nonadaptive hypotheses on the evolution of eukaryotic genome size predict an expansion when the process of purifying selection becomes weak. Accordingly, species with huge genomes, such as lungfish, are expected to show a genome-wide relaxation signature of selection compared with other organisms. However, few studies have empirically tested this prediction using genomic data in a comparative framework. Here, we show that 1) the newly assembled transcriptome of the Australian lungfish, Neoceratodus forsteri, is characterized by an excess of pervasive transcription, or transcriptional leakage, possibly due to suboptimal transcriptional control, and 2) a significant relaxation signature in coding genes in lungfish species compared with other vertebrates. Based on these observations, we propose that the largest known animal genomes evolved in a nearly neutral scenario where genome expansion is less efficiently constrained.

Genome-Wide SNPs Identify Limits to Connectivity in the Extreme Freshwater Disperser, Spangled Perch Leiopotherapon unicolor (Terapontidae)

The utility of restriction-site associated DNA sequencing (RADseq) to resolve fine-scale population structure was tested on an abundant and vagile fish species in a tropical river. Australia's most widespread freshwater fish, the "extreme disperser" Leiopotherapon unicolor was sampled from 6 locations in an unregulated system, the Daly River in Australia's Northern Territory. Despite an expectation of high connectivity based on life history knowledge of this species derived from arid zone habitats, L. unicolor was not a panmictic population in the tropical lower Daly. Using ~14000 polymorphic RADseq loci, we found a pattern of upstream versus downstream population subdivision and evidence for differentiation among tributary populations. The magnitude of population structure was low with narrow confidence intervals (global FST = 0.014; 95% CI = 0.012-0.016). Confidence intervals around pairwise FST estimates were all nonzero and consistent with the results of clustering analyses. This population structure was not explained by spatially heterogeneous selection acting on a subset of loci, or by sampling groups of closely related individuals (average within-site relatedness ≈ 0). One implication of the low but significant structure observed in the tropics is the possibility that L. unicolor may exhibit contrasting patterns of migratory biology in tropical versus arid zone habitats. We conclude that the RADseq revolution holds promise for delineating subtle patterns of population subdivision in species characterized by high within-population variation and low among-population differentiation.

Systematics of the palisade trapdoor spiders (Euoplos) of south-eastern Queensland (Araneae : Mygalomorphae : Idiopidae): four new species distinguished by their burrow entrance architecture

Within the spiny trapdoor spider genus Euoplos Rainbow exists a group of species from south-eastern Queensland that create unusual ‘palisade’ burrow entrances. Despite their intriguing burrows, the group was only recently circumscribed, and all species within it were undescribed. In this study, by undertaking a molecular phylogenetic analysis of two mitochondrial markers and seven nuclear markers, we confirm that the palisade trapdoor spiders, here formally named the ‘turrificus-group’, are monophyletic. We further recognise four species based on morphological, molecular and behavioural characters: E. crenatus, sp. nov., E. goomboorian, sp. nov., E. thynnearum, sp. nov. and E. turrificus, sp. nov. Morphological taxonomic data for each species are presented alongside information on their distribution, habitat preferences and burrow architecture. A key to species within the turrificus-group is also provided. The unusual burrow entrances of these spiders, which project out from the surrounding substrate, are found to exhibit structural autapomorphies, which allow species-level identification. Consequently, we include features of burrow architecture in our key and species diagnoses. This provides a non-intrusive method for distinguishing species in the field. Finally, we conclude that all species within the turrificus-group are likely to represent short-range endemic taxa. http://zoobank.org/urn:lsid:zoobank.org:pub:F2E042DC-DA14-4751-A48B-A367ABC272D9

The complete mitogenome of Caridina indistincta 'sp. A' (Decapoda: Atyidae)

A complete mitochondrial genome sequence was determined for a member of the Caridina indistincta species complex known as C. indistincta 'sp. A'. The 15,461 bp sequence (GenBank: MH189850) was obtained via genome skimming, and contains 13 protein coding genes, 22 tRNA genes, 2 rRNA genes, and a 646 bp control region arranged in the pancrustacean ground pattern. Caridina indistincta sp. A is a freshwater macroinvertebrate important for ecosystem health monitoring in Australia and this reference will be a useful resource for metabarcoding and eDNA studies.

Monitoring age-related trends in genomic diversity of Australian lungfish

An important challenge for conservation science is to detect declines in intraspecific diversity so that management action can be guided towards populations or species at risk. The lifespan of Australian lungfish (Neoceratodus forsteri) exceeds 80 years, and human impacts on breeding habitat over the last half century may have impeded recruitment, leaving populations dominated by old postreproductive individuals, potentially resulting in a small and declining breeding population. Here, we conduct a "single-sample" evaluation of genetic erosion within contemporary populations of the Australian lungfish. Genetic erosion is a temporal decline in intraspecific diversity due to factors such as reduced population size and inbreeding. We examined whether young individuals showed signs of reduced genetic diversity and/or inbreeding using a novel bomb radiocarbon dating method to age lungfish nonlethally, based on 14 C ratios of scales. A total of 15,201 single nucleotide polymorphic (SNP) loci were genotyped in 92 individuals ranging in age from 2 to 77 years old. Standardized individual heterozygosity and individual inbreeding coefficients varied widely within and between riverine populations, but neither was associated with age, so perceived problems with recruitment have not translated into genetic erosion that could be considered a proximate threat to lungfish populations. Conservation concern has surrounded Australian lungfish for over a century. However, our results suggest that long-lived threatened species can maintain stable levels of intraspecific variability when sufficient reproductive opportunities exist over the course of a long lifespan.

Patterns of genetic structuring at the northern limits of the Australian smelt (Retropinna semoni) cryptic species complex

Freshwater fishes often exhibit high genetic population structure due to the prevalence of dispersal barriers (e.g., waterfalls) whereas population structure in diadromous fishes tends to be weaker and driven by natal homing behaviour and/or isolation by distance. The Australian smelt (Retropinnidae: Retropinna semoni) is a native fish with a broad distribution spanning inland and coastal drainages of south-eastern Australia. Previous studies have demonstrated variability in population genetic structure and movement behaviour (potamodromy, facultative diadromy, estuarine residence) across the southern part of its geographic range. Some of this variability may be explained by the existence of multiple cryptic species. Here, we examined genetic structure of populations towards the northern extent of the species’ distribution, using ten microsatellite loci and sequences of the mitochondrial cyt b gene. We tested the hypothesis that genetic connectivity among rivers should be low due to a lack of dispersal via the marine environment, but high within rivers due to dispersal. We investigated populations corresponding with two putative cryptic species, SEQ-North (SEQ-N), and SEQ-South (SEQ-S) lineages occurring in south east Queensland drainages. These two groups formed monophyletic clades in the mtDNA gene tree and among river phylogeographic structure was also evident within each clade. In agreement with our hypothesis, highly significant overall F_ST values suggested that both groups exhibit very low dispersal among rivers (SEQ-S F_ST = 0.13; SEQ-N F_ST= 0.27). Microsatellite data indicated that connectivity among sites within rivers was also limited, suggesting dispersal may not homogenise populations at the within-river scale. Northern groups in the Australian smelt cryptic species complex exhibit comparatively higher among-river population structure and smaller geographic ranges than southern groups. These properties make northern Australian smelt populations potentially susceptible to future conservation threats, and we define eight genetically distinct management units along south east Queensland to guide future conservation management. The present findings at least can assist managers to plan for effective conservation and management of different fish species along coastal drainages of south east Queensland, Australia.

Spiny trapdoor spiders (Euoplos) of eastern Australia: Broadly sympatric clades are differentiated by burrow architecture and male morphology

Spiders of the infraorder Mygalomorphae are fast becoming model organisms for the study of biogeography and speciation. However, these spiders can be difficult to study in the absence of fundamental life history information. In particular, their cryptic nature hinders comprehensive sampling, and linking males with conspecific females can be challenging. Recently discovered differences in burrow entrance architecture and male morphology indicated that these challenges may have impeded our understanding of the trapdoor spider genus Euoplos in Australia's eastern mesic zone. We investigated the evolutionary significance of these discoveries using a multi-locus phylogenetic approach. Our results revealed the existence of a second, previously undocumented, lineage of Euoplos in the eastern mesic zone. This new lineage occurs in sympatry with a lineage previously known from the region, and the two are consistently divergent in their burrow entrance architecture and male morphology, revealing the suitability of these characters for use in phylogenetic studies. Divergent burrow entrance architecture and observed differences in microhabitat preferences are suggested to facilitate sympatry and syntopy between the lineages. Finally, by investigating male morphology and plotting it onto the phylogeny, we revealed that the majority of Euoplos species remain undescribed, and that males of an unnamed species from the newly discovered lineage had historically been linked, erroneously, to a described species from the opposite lineage. This paper clarifies the evolutionary relationships underlying life history diversity in the Euoplos of eastern Australia, and provides a foundation for urgently needed taxonomic revision of this genus.

Complete mitogenomes for two lineages of the Australian smelt, Retropinna semoni (Osmeriformes: Retropinnidae)

Complete mitochondrial genome sequences were determined for two lineages (“CEQ” and “SEQ”) of the Australian smelt, Retropinna semoni. Both mitogenomes contain the typical vertebrate arrangement of 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes and control region. A conventional start codon for ND2 was not present in either lineage; instead CTG (Leucine) was present at this position. These sequences will be a useful resource for evolutionary studies of a significant species complex in the Australian freshwater fish fauna.

Diversity and phylogeny of south-east Queensland Bathynellacea

The crustacean order Bathynellacea is amongst the most diverse and widespread groups of subterranean aquatic fauna (stygofauna) in Australia. Interest in the diversity and biogeography of Australian Bathynellacea has grown markedly in recent years. However, relatively little information relating to this group has emerged from Queensland. The aim of this study was to investigate bathynellacean diversity and phylogeny in south-east Queensland. Relationships between the south-east Queensland fauna and their continental relatives were evaluated through the analysis of combined mitochondrial and nuclear DNA sequence data. Bathynellaceans were collected from alluvial groundwater systems in three catchments in south-east Queensland. This study revealed a diverse bathynellacean fauna with complex evolutionary relationships to related fauna elsewhere in Queensland, and on the wider Australian continent. The multifamily assemblage revealed here is likely to represent several new species, and at least one new genus within the Parabathynellidae. These taxa likely have relatively restricted geographic distributions. Interestingly, the south-east Queensland Bathynellacea appeared to be distantly related to their north-east Queensland counterparts. Although it was not possible to determine the generic identities of their closest relatives, the south-east Queensland Parabathynellidae appear to be most closely affiliated with southern and eastern Australian lineages. Together with previous survey data, the findings here suggest that there is likely to be considerable bathynellacean diversity in alluvial groundwater systems across the wider Queensland region. Further assessment of stygofauna distributions in south-east Queensland is necessary to understand the biological implications of significant groundwater use and development in the region.

Complete mitochondrial genome of the endangered Mary River turtle (Elusor macrurus) and low mtDNA variation across the species' range

Elusor macrurus is an endangered short-necked turtle restricted to the Mary River catchment in south-eastern Queensland. Shotgun sequencing of genomic DNA was used to generate a complete mitochondrial genome sequence for E. macrurus using the Illumina MiSeq platform. The mitogenome is 16 499 base pairs (bp) long with 37 genes arranged in the typical vertebrate order and a relatively short 918-bp control region, which does not feature extensive tandem repeats as observed in some turtles. Primers were designed to amplify a 1270-bp region that includes 81% of the typically hypervariable control region. Two haplotypes were detected in a sample of 22 wild-caught individuals from eight sites across its natural range. The Mary River turtle is a species with low mtDNA nucleotide variability relative to other Chelidae. The combination of a very restricted distribution and dramatic reduction in population size due to exploitation for the pet trade are the conditions likely to have led to very low mtDNA variability in this endangered species.

The complete mitogenome of an Australian carp gudgeon, hybridogenetic biotype HAHB (Hypseleotris: Eleotridae)

The complete mitochondrial genome was determined for a member of the Australian carp gudgeon species complex (Hypseleotris: Eleotridae). The 16 506 bp genome was recovered by direct shotgun sequencing of a wild-caught F1 hybrid male, and it contains the typical vertebrate arrangement of 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes, and a control region. This is the first published mitogenome for the genus Hypseleotris and will be useful for evolutionary studies of the carp gudgeon complex which contains a mixture of sexual species and hybridogenetic biotypes.

Phylogeography and limited distribution of the endangered freshwater crayfish, Euastacus urospinosus

Conservation plans can benefit from understanding patterns of genetic structure because many endangered species are spatially fragmented. In particular, headwater species in high elevations are expected to exhibit a high level of population structure, as dispersal through lowland streams may be limited. Euastacus urospinosus is an endangered freshwater crayfish that, until recently, was thought to have a distribution of just 200 km2. In the current study, we identified a total of 26 locations for this species across a 1225 km2 region spanning the Brisbane and Mary River catchments of south-east Queensland, Australia. We then used mitochondrial DNA sequence data to investigate the population structure and the phylogeographic divergence between four uplands. We found significant population differentiation for this species, which conforms to the headwater model of genetic structure. Further, we found that fragmentation between these uplands is most likely historical, as the first divergence between lineages dated back 2.1 million years. Overall, we found no reason to remove the conservation rating of ‘endangered’ for this species. Conservation plans should seek to preserve the genetic integrity of these uplands by considering them to be genetically distinct and isolated populations.

Multilayer transfer printing of electroactive thin film composites

We demonstrate the high fidelity transfer printing of an electroactive polymer nanocomposite thin film onto a conductive electrode. Polyelectrolyte multilayer thin films of thickness ∼200 nm containing 68 vol % Prussian Blue nanoparticles are assembled on a UV-curable photopolymer stamp and transferred in their entirety onto ITO-coated glass creating ∼2.5 μm-wide line patterns with ∼1.25 μm spacing. AFM and SEM are used to investigate pattern fidelity and morphology, while cyclic voltammetry confirms the electroactive nature of the film and electrical connectivity with the electrode. The patterning strategy presented here could be used to pattern electroactive thin films containing a high density of nanoparticles onto individually addressable microelectrodes for a variety of applications ranging from biosensor arrays to flexible electronics.

Shared phylogeographic patterns between the ectocommensal flatworm Temnosewellia albata and its host, the endangered freshwater crayfish Euastacus robertsi

Comparative phylogeography of commensal species may show congruent patterns where the species involved share a common history. Temnosewellia is a genus of flatworms, members of which live in commensal relationships with host freshwater crustaceans. By constructing phylogenetic trees based on mitochondrial COI and 28S nuclear ribosomal gene sequences, this study investigated how evolutionary history has shaped patterns of intraspecific molecular variation in two such freshwater commensals. This study concentrates on the flatworm Temnosewellia albata and its critically endangered crayfish host Euastacus robertsi, which have a narrow climatically-restricted distribution on three mountaintops. The genetic data expands upon previous studies of Euastacus that suggested several vicariance events have led to the population subdivision of Euastacus robertsi. Further, our study compared historical phylogeographic patterning of these species. Our results showed that phylogeographic patterns shared among these commensals were largely congruent, featuring a shared history of limited dispersal between the mountaintops. Several hypotheses were proposed to explain the phylogeographic points of differences between the species. This study contributes significantly to understanding evolutionary relationships of commensal freshwater taxa.

Genetic structuring of remnant forest patches in an endangered medicinal tree in North-western Ethiopia

Background

Habitat loss and fragmentation may have detrimental impacts on genetic diversity, population structure and overall viability of tropical trees. The response of tropical trees to fragmentation processes may, however, be species, cohort or region-specific. Here we test the hypothesis that forest fragmentation is associated with lower genetic variability and higher genetic differentiation in adult and seedling populations of Prunus africana in North-western Ethiopia. This is a floristically impoverished region where all but a few remnant forest patches have been destroyed, mostly by anthropogenic means.

Results

Genetic diversity (based on allelic richness) was significantly greater in large and less-isolated forest patches as well as in adults than seedlings. Nearly all pairwise F_ST comparisons showed evidence for significant population genetic differentiation. Mean F_ST values were significantly greater in seedlings than adults, even after correction for within population diversity, but varied little with patch size or isolation.

Conclusions

Analysis of long-lived adult trees suggests the formerly contiguous forest in North-western Ethiopia probably exhibited strong spatial patterns of genetic structure. This means that protecting a range of patches including small and isolated ones is needed to conserve the extant genetic resources of the valuable forests in this region. However, given the high livelihood dependence of the local community and the high impact of foreign investors on forest resources of this region, in situ conservation efforts alone may not be helpful. Therefore, these efforts should be supported with ex situ gene conservation actions.

Low interbasin connectivity in a facultatively diadromous fish: evidence from genetics and otolith chemistry

Southern smelts (Retropinna spp.) in coastal rivers of Australia are facultatively diadromous, with populations potentially containing individuals with diadromous or wholly freshwater life histories. The presence of diadromous individuals is expected to reduce genetic structuring between river basins due to larval dispersal via the sea. We use otolith chemistry to distinguish between diadromous and nondiadromous life histories and population genetics to examine interbasin connectivity resulting from diadromy. Otolith strontium isotope ((87) Sr:(86) Sr) transects identified three main life history patterns: amphidromy, freshwater residency and estuarine/marine residency. Despite the potential for interbasin connectivity via larval mixing in the marine environment, we found unprecedented levels of genetic structure for an amphidromous species. Strong hierarchical structure along putative taxonomic boundaries was detected, along with highly structured populations within groups using microsatellites (FST  = 0.046-0.181), and mtDNA (ΦST  = 0.498-0.816). The presence of strong genetic subdivision, despite the fact that many individuals reside in saline water during their early life history, appears incongruous. However, analysis of multielemental signatures in the otolith cores of diadromous fish revealed strong discrimination between river basins, suggesting that diadromous fish spend their early lives within chemically distinct estuaries rather than the more homogenous marine environment, thus avoiding dispersal and maintaining genetic structure.

A phylogenetic analysis using full-length viral genomes of South American dengue serotype 3 in consecutive Venezuelan outbreaks reveals a novel NS5 mutation

Dengue virus currently causes 50-100 million infections annually. Comprehensive knowledge about the evolution of Dengue in response to selection pressure is currently unavailable, but would greatly enhance vaccine design efforts. In the current study, we sequenced 187 new dengue virus serotype 3 (DENV-3) genotype III whole genomes isolated from Asia and the Americas. We analyzed them together with previously-sequenced isolates to gain a more detailed understanding of the evolutionary adaptations existing in this prevalent American serotype. In order to analyze the phylogenetic dynamics of DENV-3 during outbreak periods; we incorporated datasets of 48 and 11 sequences spanning two major outbreaks in Venezuela during 2001 and 2007-2008, respectively. Our phylogenetic analysis of newly sequenced viruses shows that subsets of genomes cluster primarily by geographic location, and secondarily by time of virus isolation. DENV-3 genotype III sequences from Asia are significantly divergent from those from the Americas due to their geographical separation and subsequent speciation. We measured amino acid variation for the E protein by calculating the Shannon entropy at each position between Asian and American genomes. We found a cluster of seven amino acid substitutions having high variability within E protein domain III, which has previously been implicated in serotype-specific neutralization escape mutants. No novel mutations were found in the E protein of sequences isolated during either Venezuelan outbreak. Shannon entropy analysis of the NS5 polymerase mature protein revealed that a G374E mutation, in a region that contributes to interferon resistance in other flaviviruses by interfering with JAK-STAT signaling was present in both the Asian and American sequences from the 2007-2008 Venezuelan outbreak, but was absent in the sequences from the 2001 Venezuelan outbreak. In addition to E, several NS5 amino acid changes were unique to the 2007-2008 epidemic in Venezuela and may give additional insight into the adaptive response of DENV-3 at the population level.

Layer-by-layer assembled polyaniline nanofiber/multiwall carbon nanotube thin film electrodes for high-power and high-energy storage applications

Thin film electrodes of polyaniline (PANi) nanofibers and functionalized multiwall carbon nanotubes (MWNTs) are created by layer-by-layer (LbL) assembly for microbatteries or -electrochemical capacitors. Highly stable cationic PANi nanofibers, synthesized from the rapid aqueous phase polymerization of aniline, are assembled with carboxylic acid functionalized MWNT into LbL films. The pH-dependent surface charge of PANi nanofibers and MWNTs allows the system to behave like weak polyelectrolytes with controllable LbL film thickness and morphology by varying the number of bilayers. The LbL-PANi/MWNT films consist of a nanoscale interpenetrating network structure with well developed nanopores that yield excellent electrochemical performance for energy storage applications. These LbL-PANi/MWNT films in lithium cell can store high volumetric capacitance (~238 ± 32 F/cm(3)) and high volumetric capacity (~210 mAh/cm(3)). In addition, rate-dependent galvanostatic tests show LbL-PANi/MWNT films can deliver both high power and high energy density (~220 Wh/L(electrode) at ~100 kW/L(electrode)) and could be promising positive electrode materials for thin film microbatteries or electrochemical capacitors.

Cytonuclear evidence for hybridogenetic reproduction in natural populations of the Australian carp gudgeon (Hypseleotris: Eleotridae)

Although most vertebrates reproduce sexually, a small number of fishes, amphibians and reptiles are known in which reproduction is asexual, i.e. without meiotic recombination. In fishes, these so-called unisexual lineages usually comprise only females and utilize co-occurring males of a related sexual species to reproduce via gynogenesis or hybridogenesis. Here, we examine patterns of microsatellite and mitochondrial DNA (mtDNA) variation in a widespread group of freshwater fishes (carp gudgeons; Hypseleotris spp.) to investigate a long-standing proposal that this group includes unisexual forms. We show that the mtDNA genome of most carp gudgeons in tributaries of the Goulburn River belongs to one of two deeply divided clades (∼10% cyt b divergence) and that nuclear variation divides the same individuals into four distinct groups. Group 1 exhibits the genotypic proportions of a random mating population and has a 1:1 sex ratio. Two other groups are extremely sex-biased (98% male, 96% female), exhibit excess heterozygosity at most loci and share at least one allele per locus with group 1. We propose that these two groups represent 'unisexual' hybridogenetic lineages and that both utilize co-occurring group 1 as sexual host. Interestingly, the fourth distinct group appears to represent hybrid offspring of the two putative hybridogenetic lineages. The propagation of clonal haploid genomes by both males and females and the ability of these clones to unite and form sexually mature diploid hybrid offspring may represent a novel mechanism that contributes to the dynamics of coexistence between hybridogenetic lineages and their sexual hosts.

Genetic analysis of threatened Australian grayling Prototroctes maraena suggests recruitment to coastal rivers from an unstructured marine larval source population

Population genetic variation of Australian grayling Prototroctes maraena was examined to determine whether the dispersal strategy of this amphidromous species favours retention of larvae and juveniles in close proximity to their natal river, or mixing of populations via marine dispersal. Variation in microsatellite and mitochondrial DNA markers was unstructured and differentiation was indistinguishable from zero across four coastal rivers spanning approximately one-quarter of the continental range of the species. This result indicates that the marine larval and juvenile phase probably facilitates extensive gene flow among coastal rivers and agrees with a previous analysis of otolith chemistry that suggested larvae probably move into the sea rather than remain in estuaries. It appears likely that the dispersal strategy of P. maraena would enable recolonization of rivers that experience localized extinction provided that connectivity between freshwater habitats and the sea is sufficient to permit migration and that enough source populations remain intact to support viability of the wider population.

Electrically Triggered Release of a Small Molecule Drug from a Polyelectrolyte Multilayer Coating

Electrically triggered drug delivery represents an attractive option for actively and remotely controlling the release of a therapeutic from an implantable device (e.g., a "pharmacy-on-a-chip"). Here we report the fabrication of nanoscale thin films that can release precise quantities of a small molecule drug in response to application of a small, anodic electric potential of at least +0.5 V versus Ag/AgCl. Films containing negatively charged Prussian Blue (PB) nanoparticles and positively charged gentamicin, a small hydrophilic antibiotic, were fabricated using layer-by-layer (LbL) assembly. When oxidized, the PB nanoparticles shift from negatively charged to neutral, inducing dissolution of the film. Films with thicknesses in the range 100-500 nm corresponding to drug loadings of 1-4 μg/cm(2) were characterized. We demonstrate control over the drug dosage by tuning the film thickness as well as the magnitude of the applied voltage. Drug release kinetics ranging from triggered burst release to on/off, or pulsatile release, were achieved by applying different electric potential profiles. Finally, the in vitro efficacy of the released drug was confirmed against Staphylococcus aureus bacteria. Given the versatility of an external electrical stimulus and the ability of LbL assembly to conformally coat a variety of substrates regardless of size, shape, or chemical composition, we maintain that electrically controlled release of a drug from an LbL-coated surface could have applications in both implantable medical devices and transdermal drug delivery systems.

Electrochemically controlled swelling and mechanical properties of a polymer nanocomposite

We present the layer-by-layer assembly of an electroactive polymer nanocomposite thin film containing cationic linear poly(ethyleneimine) (LPEI) and 68 vol % anionic Prussian Blue (PB) nanoparticles, which allow for electrochemical control over film thickness and mechanical properties. Electrochemical reduction of the PB doubles the negative charge on the particles, causing an influx of water and ions from solution to maintain electroneutrality in the film; concomitant swelling and increased elastic compliance of the film result. Reversible swelling upon reduction is on the order of 2-10%, as measured via spectroscopic ellipsometry and electrochemical atomic force microscopy. Reversible changes in the Young's elastic modulus of the hydrated composite film upon reduction are on the order of 50% (from 3.40 to 1.75 GPa) as measured with in situ nanoindentation, and a qualitative increase in viscous contributions to energy dissipation upon redox is indicated by electrochemical quartz crystal microbalance. Electrochemical stimuli maintain a mild operating environment and can be applied rapidly, reversibly, and locally. We maintain that electrochemical control over the swelling and mechanical behavior of polymer nanocomposites could have important implications for responsive coatings of nanoscale devices, including mechanically tunable surfaces to modulate behavior of adherent cells.

Electroactive controlled release thin films

We present the fabrication of nanoscale electroactive thin films that can be engineered to undergo remotely controlled dissolution in the presence of a small applied voltage (+1.25 V) to release precise quantities of chemical agents. These films, which are assembled by using a nontoxic, FDA-approved, electroactive material known as Prussian Blue, are stable enough to release a fraction of their contents after the application of a voltage and then to restabilize upon its removal. As a result, it is possible to externally trigger agent release, exert control over the relative quantity of agents released from a film, and release multiple doses from one or more films in a single solution. These electroactive systems may be rapidly and conformally coated onto a wide range of substrates without regard to size, shape, or chemical composition, and as such they may find use in a host of new applications in drug delivery as well as the related fields of tissue engineering, medical diagnostics, and chemical detection.

Taxonomy, ecology, genetics and conservation status of the pale imperial hairstreak (Jalmenus eubulus) (Lepidoptera:Lycaenidae): a threatened butterfly from the Brigalow Belt, Australia

The taxonomic status of Jalmenus eubulus Miskin stat. rev. is revised and considered to be specifically distinct from J. evagoras (Donovan) based on fundamental differences in morphology, ecology and genetics. Miskin’s holotype is fixed by monotypy and illustrated, with type locality Rockhampton, Queensland. Fixed differences in the mitochondrial genomes of J. eubulus and J. evagoras in which the mean pairwise divergence is only 0.85% indicate absence of matrilineal gene flow, whereas allozyme data show significant structure within and between populations of both species consistent with recent diversification. Underlying causes for the observed genetic patterns are investigated. The two species are parapatric, with a narrow range of overlap along the Great Escarpment in south-eastern Queensland. Jalmenus eubulus is restricted to vegetation communities comprising brigalow-dominated old-growth open-forests and woodlands in the Brigalow Belt (with larvae monophagous on Acacia harpophylla F. Muell. Ex Benth), whereas J. evagoras occurs in a range of disturbed eucalypt woodlands/open-forests predominantly in montane and coastal areas east of this bioregion (with larvae polyphagous on Acacia species other than A. harpophylla). The conservation status of J. eubulus is considered to be vulnerable nationally and critically endangered in New South Wales according to International Union for Conservation of Nature (IUCN) criteria. Nationally, the geographic range has an estimated area of occupancy of less than 2000 km2, is severely fragmented, and the extent or quality of its habitat, which is poorly conserved, continues to decline. It is recommended that the taxon be used as an indicator for identification of remnant old-growth forest for conservation planning, as well as a flagship for the conservation of invertebrate biodiversity associated with this threatened ecological community.

Length-dependent extraction of single-walled carbon nanotubes

A two-phase liquid-liquid extraction process is presented which is capable of extracting water-soluble single-walled carbon nanotubes into an organic phase. The extraction utilizes electrostatic interactions between a common phase transfer agent and the sidewall functional groups on the nanotubes. Large length-dependent van der Waals forces for nanotubes allow the ability to control the length of nanotubes extracted into the organic phase as demonstrated by atomic force microscopy.

Cutting single-walled carbon nanotubes

A two-step process is utilized for cutting single-walled carbon nanotubes (SWNTs). The first step requires the breakage of carbon-carbon bonds in the lattice while the second step is aimed at etching at these damage sites to create short, cut nanotubes. To achieve monodisperse lengths from any cutting strategy requires control of both steps. Room-temperature piranha and ammonium persulfate solutions have shown the ability to exploit the damage sites and etch SWNTs in a controlled manner. Despite the aggressive nature of these oxidizing solutions, the etch rate for SWNTs is relatively slow and almost no new sidewall damage is introduced. Carbon-carbon bond breakage can be introduced through fluorination to ∼C(2)F, and subsequent etching using piranha solutions has been shown to be very effective in cutting nanotubes. The final average length of the nanotubes is approximately 100 nm with carbon yields as high as 70-80%.

Alternative indicator bacteria analyses for evaluating the sanitary condition of beef carcasses

Sponge samples were obtained from 47 (study 1) and 32 (study 2) beef carcasses in a small plant over 6 months. In study 2, slaughter equipment surfaces were also sampled. In study 1, the Petrifilm method was used to count presumptive Escherichia coli and spread plating on kanamycin esculin azide (KEA) agar with and without 40% added bile was used to count presumptive Enterococcus spp. Qualitative testing for presumptive E. coli and Enterococcus spp. in study 1 was done using lauryl sulfate tryptone broth (LST) + 4-methylumbelliferyl-beta-D-glucuronide (MUG) and KEA + 40% bile broth, respectively. In study 2, LST + MUG was used as a most probable number (MPN) method along with the Petrifilm method. In the two studies, 8 (17.0%) and 11 (34.4%) carcasses were contaminated with presumptive E. coli; all but one contaminated carcass contained <1 CFU/cm2. Presumptive Enterococcus spp. were recovered from 15 carcasses (31.9%) in study 1, but the KEA + 40% bile agar method lacked specificity (only 31.3% of isolates confirmed as Enterococcus spp.) The LST + MUG and Petrifilm methods were significantly (P < 0.05) related in terms of detecting presumptive E. coli, but the presence of presumptive Enterococcus spp. was not significantly related to the presence of presumptive E. coli. However, on slaughter plant equipment in Study 2 there was a statistically significant (P < 0.05) relationship between the presence of presumptive E. coli and presumptive Enterococcus spp. In study 2, there was no significant (P < 0.05) difference in numbers of presumptive E. coli (obtained using Petrifilm) on carcasses chilled 1 day (n = 16) and 7 days (n = 16), although more of the 7-day carcasses were contaminated (five and seven carcasses, respectively). For samples testing positive for presumptive E. coli, the 95% confidence intervals obtained using the LST + MUG MPN method included the Petrifilm value for all but one sample.

Distribution of active protein kinase C in smooth muscle

To localize activated protein kinase C (PKC) in smooth muscle cells, an antibody directed to the catalytic site of the enzyme was used to assess PKC distribution by immunofluorescence techniques in gastric smooth muscle cells isolated from Bufo marinus. An antibody to vinculin was used to delineate the cell membrane. High-resolution three-dimensional images of immunofluorescence were obtained from a series of images collected through focus with a digital imaging microscope. Cells were untreated or treated with agents that increase PKC activity (10 microM carbachol for 1 min, 1 microM phorbol 12-myristate 13-acetate (PMA) for 10 min), or have no effect on PKC activity (1 micrometer 4-alpha phorbol, 12,13-didecanoate (4-alpha PMA)). In unstimulated cells, activated PKC and vinculin were located and organized at the cell surface. Cell cytosol labeling for activated PKC was sparse and diffuse and was absent for vinculin. After treatment with carbachol, which stimulates contraction and PKC activity, in addition to the membrane localization, the activated PKC exhibited a pronounced cytosolic fibrillar distribution and an increased total fluorescence intensity relative to vinculin. The distributions of activated PKC observed after PMA but not 4-alpha PMA were similar to those observed with carbachol. Our results indicate that in resting cells there is a pool of activated PKC near the cell membrane, and that after stimulation activated PKC is no longer membrane-confined, but is present throughout the cytosol. Active PKC appears to associate with contractile filaments, supporting a possible role in modulation of contraction.

Length changes of the hamstrings and adductors resulting from derotational osteotomies of the femur

Derotational osteotomies of the femur are frequently performed to treat persons with cerebral palsy who walk with excessive internal rotation of the hip. However, whether these procedures stretch or slacken the surrounding muscles appreciably is unknown. Determination of how muscle lengths are altered by derotational osteotomies is difficult because the length changes depend not only on the osteotomy site and the degree of derotation, but also on the anteversion angle of the femur and the rotational position of the hip. We have developed a three-dimensional computer simulation of derotational osteotomies, tested by anatomical experiments, to examine how femoral anteversion, hip internal rotation, and derotation affect the lengths of the semitendinosus, semimembranosus, biceps femoris long head, adductor longus, adductor brevis, and gracilis muscles. Simulation of derotational osteotomies at the intertrochanteric, subtrochanteric, or supracondylar levels decreased the origin-to-insertion lengths of the hamstrings and gracilis in our model by less than 8 mm (1.8%). Hence, the lengths of the hamstrings and gracilis are not likely to be altered substantially by these procedures. The origin-to-insertion lengths of the adductor longus and adductor brevis decreased less than 4 mm (1.9%) with subtrochanteric correction in our model, but the length of adductor brevis increased 8 mm (6.3%) with 60 degrees of intertrochanteric derotation. These muscles are also unlikely to be affected by derotational osteotomies, unless a large degree of intertrochanteric derotation is performed.

Common carotid artery flow velocity measurements in the newborn period with pulsed Doppler technique

Using a commercial pulsed Doppler (PD) system we measured common carotid artery (CCA) flow velocities in 19 healthy and 6 stable preterm infants and computed volume flow rates based on the time-averaged flow velocities and vessel diameter. The mean (+/- SEM) time-averaged CCA velocities in the term and preterm infants were 33.04 +/- 3.0 and 23.3 +/- 1.3 cm.s-1, respectively. The total flow volume was significantly higher in the term as opposed to preterm infants: 126 +/- 11.2 vs. 55.6 +/- 7.7 ml/min (p less than 0.01). The body-weight-normalized flow volume, however, was not statistically significantly different between the two groups of infants. Several technical and practical limitations still exist to compute cerebral blood flow (CBF) volume accurately. In a puppy model we measured the CCA flow volume by electromagnetic flowmeter technique, and the PD device simultaneously. The correlation coefficient between 32 pairs of measurements was 0.93 (p less than 0.005). We conclude that commercial PD devices provide accurate velocity data, and under experimental conditions, the computed volume flow rates are accurate. Although in clinical situations reasonably accurate CBF values can be estimated, refinements in technology are needed to adopt this method as a possible means of measuring CBF at the bedside.

The pathogenesis of experimental pulmonary histoplasmosis. Correlative studies of histopathology, bronchoalveolar lavage, and respiratory function

A murine model of acute pulmonary histoplasmosis was employed to study the pathogenesis of the disease process by means of histopathology, bronchoalveolar lavage, and respiratory function tests. These studies were performed on C57BL/6 mice from 8 h to 8 wk after intranasal inoculation of 10(5) yeast forms of Histoplasma capsulatum and on age-matched control animals that received saline only. At Week 1, the histopathology was characterized by subacute inflammation consisting of polymorphonuclear leukocytes (PMN), lymphocytes, and macrophages that infiltrated the interstitium around small bronchioles and adjacent alveoli. At Weeks 2 and 4, the infiltrates were comprised predominantly of lymphocytes and macrophages; noncaseating granulomas were present at Week 2. Aggregates of lymphoid cells were prominent along the bronchial tree and in perivascular distribution. Those in close contact with bronchiolar epithelium resembled hyperplastic bronchus associated lymphoid tissue. Quantitative studies of cells in the BAL fluid revealed a large influx of PMN at Week 1 with return to normal range by Week 2. At this time there was a significant (p less than 0.02) increase in lymphocytes that persisted through Week 8, although histopathologic changes were minimal in lung at this time. A significant decrease in the DLCO/TLC at Week 2 in association with a normal vital capacity indicated impairment of respiratory function secondary to the alveolitis induced by H. capsulatum infection rather than a reduction of lung volume. This model offers promise for additional correlative studies of lymphocyte subsets in lung tissue and alveolar spaces as well as of the functions subserved by these respective populations.

Toluene diisocyanate-induced airway hyperreactivity and pathology in the guinea pig

We assessed the nature and progression of airway mucosal disease and histaminic reactivity in English short-haired guinea pigs at 2, 24, 72, 168, and 504 hours after toluene diisocyanate (TDI) exposure (4 hours of 3 ppm of TDI for 5 consecutive days). To also determine whether TDI-specific, IgE-like antibodies developed in TDI-exposed animals, passive cutaneous anaphylaxis testing was done 28 days after TDI. Bronchial reactivity was determined serially by measuring specific airway conductance as a function of increasing doses of aerosolized histamine in six exposed and three control animals studied intact and unanesthetized. The remaining 10 exposed and 10 control guinea pigs were sacrificed in groups of two at each time point to obtain airway tissue for light microscopic examination. We found that airway hyperreactivity to histamine occurred after TDI in all animals tested. It was maximal 2 hours after the 5-day exposure and remitted by 72 hours. In addition, marked airway obstruction occurred after TDI that persisted for at least 168 hours. There were dramatic signs of airway mucosal damage associated with the bronchial hyperreactivity that included substantial decreases in epithelial cilia, mucin content, and mast cells, as well as squamous metaplasia, numerous mitotic figures, and a prominent polymorphonuclear leukocytic infiltrate. Passive cutaneous anaphylaxis tests in exposed animals were negative. Our results suggest that TDI-induced bronchial hyperreactivity may be related to airway mucosal injury and inflammation.

Determination of sex with a discriminant analysis of new pelvic bone measurements: Part II

The pelves of 100 white skeletons were measured on both sides for the following: (1) length from the superiormost aspect of the pubic symphysis to the nearest rim of the acetabulum (PS-A), (2) length from the highest point of the pubic tubercle to the nearest rim of the acetabulum (PT-A), (3) acetabular diameter (AD), (4) the vertical distance from the anterior aspect of the ischial tuberosity to the farthest rim of the acetabulum (IT-A), and (5) greatest femur head diameter. From these, three indices were derived: AD/PS-A (acetabulum/pubis index), AD/PT-A (acetabular diameter/pubic tubercle-acetabular rim index), and IT-A/PS-A (ischium-acetabulum height/pubic symphysis-acetabular rim index). The left AD/PS-A ratio and left IT-A height proved statistically to be of greatest discriminating value. Using these two variables, a discriminant function was derived which correctly separated 98% of our sample. The acetabulum/pubis ratio alone correctly assigned 95%. With either the discriminant function analysis of two variables or the acetabulum/pubis index as a single predictor, 97% of our sample of known sex was correctly identified if all specimens that fell within a doubtful or overlapping range of values were sorted by femur head diameter.