Using multiple landscape genetic approaches to test the validity of genetic clusters in a species characterized by an isolation-by-distance pattern

Bayesian clustering methods are typically used to identify barriers to gene flow, but they are prone to deduce artificial subdivisions in a study population characterized by an isolation-by-distance pattern (IbD). Here we analysed the landscape genetic structure of a population of wild boars (Sus scrofa) from south-western Germany. Two clustering methods inferred the presence of the same genetic discontinuity. However, the population in question was characterized by a strong IbD pattern. While landscape-resistance modelling failed to identify landscape features that influenced wild boar movement, partial Mantel tests and multiple regression of distance matrices (MRDMs) suggested that the empirically inferred clusters were separated by a genuine barrier. When simulating random lines bisecting the study area, 60% of the unique barriers represented, according to partial Mantel tests and MRDMs, significant obstacles to gene flow. By contrast, the random-lines simulation showed that the boundaries of the inferred empirical clusters corresponded to the most important genetic discontinuity in the study area. Given the degree of habitat fragmentation separating the two empirical partitions, it is likely that the clustering programs correctly identified a barrier to gene flow. The differing results between the work published here and other studies suggest that it will be very difficult to draw general conclusions about habitat permeability in wild boar from individual studies.

Petrographical classification and mineral assemblage of basement clasts from the Quaternary and Miocene sections of sediment core CRP-1 (Table 1)

Petrographical and mineral chemistry data are described for the mist representative basement lithologies occurring as clasts (pebble grain-size class) from the CRP-1 drillhole. Most pebbles consits of either undeformed or foliated biotite with or without hornblende monzogranites. Other rock types include biotite with or without garnet syenogranitr, biotite-hornblende granodiorite, tonalite, monzogranitic porphyries, haplogranite, quartz-monzonite (restricted to the Quaternary section), Ca-silicate rocks and biotite amphibolite (restricted to the Miocene strata). The common and ubiquitous occurence of biotite with or without hornblende monzogranite pebbles, in both the Quaternary and Miocene sections, apparently mirrors the dominance of these rock types in the granitoid assemblages which are presently exposed in the upper Precambrian-lower Paleozoic basement of the south Victoria Land. The other CRP-1 pebble lithologies show petrographical features which consitently support a dominant supply from areas of the Transantarctic Mountains located to the west and south-west of the CRP-1 site, and they thus furthercorroborate a model of local provenance for the supply of basement clasts to the CRP-1 sedimentary strata.

Cholesterol and C30 of sediment profile MD90-963

In a deep-sea sediment core recovered from a site lying well above the local lysocline, several organic geochemical proxies, and two different calcite dissolution indicators, are compared in order to evaluate the relationship between calcite dissolution and paleoproductivity over the past three glacial-interglacial cycles. The degree of foraminiferal break-up, and the CaCO3 particle size distribution, both point to significant periods of dissolution every 22 kyr during glacial stages and substages. These dissolution events are concomitant with periods of enhanced primary productivity, as indicated by the abundance of several biomarkers (alkenones, cholesterol, brassicasterol, keto-ol), used here to indicate changes in paleoproductivity. Dissolution fluctuations are highly coherent and in phase with the estimated paleoproductivity variations providing strong evidence that the observed dissolution is due to organic matter remineralization within the sediments rather, than to changes in CO32? concentration in the overlying water column.

(Table 1) Sea surface temperature reconstruction for eastern equatorial Pacific surface sediment samples

Significant uncertainties persist in the reconstruction of past sea surface temperatures in the eastern equatorial Pacific, especially regarding the amplitude of the glacial cooling and the details of the post-glacial warming. Here we present the first regional calibration of alkenone unsaturation in surface sediments versus mean annual sea surface temperatures (maSST). Based on 81 new and 48 previously published data points, it is shown that open ocean samples conform to established global regressions of Uk'37 versus maSST and that there is no systematic bias from seasonality in the production or export of alkenones, or from surface ocean nutrient concentrations or salinity. The flattening of the regression at the highest maSSTs is found to be statistically insignificant. For the near-coastal Peru upwelling zone between 11-15°S and 76-79°W, however, we corroborate earlier observations that Uk'37 SST estimates significantly over-estimate maSSTs at many sites. We posit that this is caused either by uncertainties in the determination of maSSTs in this highly dynamic environment, or by biasing of the alkenone paleothermometer toward El Niño events as postulated by Rein et al. (2005).

Organic compounds in surface sediments from the Pakistan continental margin

In order to assess whether the oxygen-minimum zone (OMZ) in the Arabian sea has an effect on the preservation and composition of organic matter in surface sediments we investigated samples from three different transects on the Pakistan continental margin across the OMZ. In addition to determining the total amount of organic carbon (TOC), we analyzed the extractable lipids by gas chromatography, combined gas chromatography/mass spectrometry, and compound-specific stable carbon isotope measurements. The extractable lipids are dominated by marine organic matter as indicated by the abundance of lipids typical of marine biota and by the bulk and molecular isotopic composition. Sediments from within the OMZ are enriched in organic carbon and in several extractable lipids (i.e. phytol, n-alcohols, total sterols, n-C35 alkane) relative to stations above and below this zone. Other lipid concentrations, such as those of total n-fatty acids and total n-alkanes fail to show any relation to the OMZ. Only a weak correlation of TOC with mineral surface area was found in sediments deposited within the OMZ. In contrast, sediments from outside the OMZ do not show any relationship between TOC and surface area. Among the extractable lipids, only the n-alkane concentration is highly correlated with surface area in sediments from the Hab and Makran transects. In sediments from outside the OMZ, the phytol and sterol concentrations are also weakly correlated with mineral surface area. The depositional environment of the Indus Fan offers the best conditions for an enhanced preservation of organic matter. The OMZ, together with the undisturbed sedimentation at moderate rates, seems to be mainly responsible for the high TOC values in this area. Overall, the type of organic matter and its lability toward oxic degradation, the mineral surface area, the mineral composition, and possibly the secondary productivity by (sedimentary) bacteria also appear to have an influence on organic matter accumulation and composition.

Drug use patterns and mental health of regular amphetamine users during a reported 'heroin drought'

Aims The present study extends the findings of a pilot study conducted among regular amphetamine users in Newcastle, NSW, in 1998. It compares key features between current participants in a state capital city (Brisbane) and a regional city (Newcastle) and between the 1998 and current Newcastle sample. Design Cross-sectional survey. Setting Brisbane and Newcastle, Australia. Participants The survey was conducted among 214 regular amphetamine users within the context of a randomized controlled trial of brief interventions for amphetamine use. Measurements Demographic characteristics, past and present alcohol and other drug use and mental health, treatment, amphetamine-related harms and severity of dependence. Findings The main findings were as follows: (i) the rate of mental health problems was high among regular amphetamine users and these problems commonly emerged after commencement of regular amphetamine use; (ii) there were regional differences in drug use with greater accessibility to a wider range of drugs in a state capital city and greater levels of injecting risk-taking behaviour outside the capital city environment; and (iii) there was a significant increase in level of amphetamine use and percentage of alcohol users, a trend for a higher level of amphetamine dependence and a significant reduction in the percentage of people using heroin and benzodiazepines among the 2002 Newcastle cohort compared to the 1998 cohort. Conclusions Further longitudinal research is needed to elucidate transitions from one drug type to another and from recreational to injecting and regular use and the relationship between drug use and mental health in prospective studies among users. Implications Intervention research should evaluate the effectiveness of interventions aimed at: preventing transition to injecting and regular use of amphetamines; toward reducing levels of depression among amphetamine users and interventions among people with severe psychopathology and personality disorders; and toward reducing the prevalence of tobacco dependence among amphetamine users.

Roles of transmembrane domain 2 and the first intracellular loop in human noradrenaline transporter function: pharmacological and SCAM analysis

The aim was to investigate the roles of transmembrane domain 2 and the adjacent region of the first intracellular loop in determining human noradrenaline transporter (hNET) function by pharmacological and substituted-cysteine accessibility method (SCAM) analyses. It was first necessary to establish a suitable background NET for SCAM. Alanine mutants of endogenous hNET cysteines, hC86A, hC131A and hC339A, were examined and showed no marked effects on expression or function. hNET and the mutants were also resistant to methanethiosulfonate (MTS), ethylammonium (MTSEA) and MTStrimethylammonium (MTSET). Hence, wild-type hNET is an appropriate background for production of cysteine mutants for SCAM. Pharmacological investigation showed that all mutants except hT99C and hL109C showed reduced cell-surface expression, while all except hM107C showed a reduction in functional activity. The mutations did not markedly affect the apparent affinities of substrates, but apparent affinities of cocaine were decreased 7-fold for hP97C and 10-fold for hF101C and increased 12-fold for hY98C. [H-3]Nisoxetine binding affinities were decreased 13-fold for hP97C and 5-fold for hF101C. SCAM analysis revealed that only hL102C was sensitive to 1.25 mM MTSEA, and this sensitivity was protected by noradrenaline, nisoxetine and cocaine. The results suggest that this region of hNET is important for interactions with antidepressants and cocaine, but it is probably not involved in substrate translocation mechanisms.

Real-time PCR assays for detection of bocavirus in human specimens

The recently discovered human bocavirus (HBoV) is the first member of the family Parpoviridae, genus Bocavirus, to be potentially associated with human disease. Several studies have identified HBoV in respiratory specimens from children with acute respiratory disease, but the full spectrum of clinical disease and the epidemiology of HBoV infection remain unclear. The availability of rapid and reliable molecular diagnostics would therefore aid future studies of this novel virus. To address this, we developed two sensitive and specific real-time TaqMan PCR assays that target the HBoV NS1 and NP-1 genes. Both assays could reproducibly detect 10 copies of a recombinant DNA plasmid containing a partial region of the HBoV genome, with a dynamic range of 8 log units (10(1) to 10(8) copies). Eight blinded clinical specimen extracts positive for HBoV by an independent PCR assay were positive by both real-time assays. Among 1,178 NP swabs collected from hospitalized pneumonia patients in Sa Kaeo Province, Thailand, 53 (4.5%) were reproducibly positive for HBoV by one or both targets. Our data confirm the possible association of HBoV infection with pneumonia and demonstrate the utility of these real-time PCR assays for HBoV detection.

Short report: Lack of sex effect on the pharmacokinetics of primaquine

The pharmacokinetics of primaquine have been well defined in male volunteers, but there is little data on the disposition of the drug in women. We compared the kinetics of primaquine in nine male and nine female healthy Australian volunteers after the administration of a single oral dose (30 mg base) of primaquine. No statistical differences were observed in the following kinetic parameters of primaquine between men and women, respectively: maximum plasma concentration (93 +/- 26 and 115 +/- 38 ng/mL; 95% confidence interval [CI] of the mean difference: -55 to 10 ng/mL; P = 0.16), area under the curve (1.1 +/- 0.5 and 1.2 +/- 0.4 mu g.h/mL; 95% CI: -0.6 to 0.3 mu g.h/mL; P = 0.54), and clearance (0.34 +/- 0.12 and 0.39 +/- 0.14 L/h/kg; 95% CI: -0.17 to 0.08 L/h/kg; P = 0.46). The clinical relevance of such findings would suggest that sex does not have to be taken into account as a factor when prescribing primaquine for radical cure or terminal prophylaxis of Plasmodium vivax malaria.