Lipid mediators in marine diatoms

Aquatic Ecology - Diatoms are eukaryotic microalgae representing one of the major groups in the marine phytoplankton, accounting for up to 40% of annual productivity at sea. They are widely...     

Single and combined effects of two trace elements (Cd and Cu) on the asexual reproduction of Aurelia sp. polyps

Aquatic Ecology - Jellyfish blooms are an increasingly common event in our seas. Occurring via polyps’ asexual reproduction induced by human stresses, they represent a hazard for ecosystems...     

BAmSA: Visualising transmembrane regions in protein complexes using biotinylated amphipols and electron microscopy

Membrane protein (MP) complexes play key roles in all living cells. Their structural characterisation is hampered by difficulties in purifying and crystallising them. Recent progress in electron microscopy (EM) have revolutionised the field, not only by providing higher-resolution structures for previously characterised MPs but also by yielding first glimpses into the structure of larger and more challenging complexes, such as bacterial secretion systems. However, the resolution of pioneering EM structures may be difficult and their interpretation requires clues regarding the overall organisation of the complexes. In this context, we present BAmSA, a new method for localising transmembrane (TM) regions in MP complexes, using a general procedure that allows tagging them without resorting to neither genetic nor chemical modification. Labels bound to TM regions can be visualised directly on raw negative-stain EM images, on class averages, or on three-dimensional reconstructions, providing a novel strategy to explore the organisation of MP complexes.     

Environmental DNA metabarcoding as an effective and rapid tool for fish monitoring in canals

We focus on a case study along an English canal comparing environmental DNA (eDNA) metabarcoding with two types of electrofishing techniques (wade-and-reach and boom-boat). In addition to corroborating data obtained by electrofishing, eDNA provided a wider snapshot of fish assemblages. Given the semi-lotic nature of canals, we encourage the use of eDNA as a fast and cost-effective tool to detect and monitor whole fish communities.     

Priming xylem for stress recovery depends on coordinated activity of sugar metabolic pathways and changes in xylem sap pH

Some plant species are capable of significant reduction of xylem embolism during recovery from drought despite stem water potential remains negative. However, the functional biology underlying this process is elusive. We subjected poplar trees to drought stress followed by a period of recovery. Water potential, hydraulic conductivity, gas exchange, xylem sap pH, and carbohydrate content in sap and woody stems were monitored in combination with an analysis of carbohydrate metabolism, enzyme activity, and expression of genes involved in sugar metabolic and transport pathways. Drought resulted in an alteration of differential partitioning between starch and soluble sugars. Upon stress, an increase in the starch degradation rate and the overexpression of sugar symporter genes promoted the efflux of disaccharides (mostly maltose and sucrose) to the apoplast. In turn, the efflux activity of the sugar‐proton cotransporters caused a drop in xylem pH. The newly acidic environment induced the activity of apoplastic invertases leading to the accumulation of monosaccharides in the apoplast, thus providing the main osmoticum necessary for recovery. During drought and recovery, a complex network of coordinated molecular and biochemical signals was activated at the interface between xylem and parenchyma cells that appeared to prime the xylem for hydraulic recovery.     

A rapid mini-prep method for isolation of ectomycorrhizal DNA from Tuber species

A rapid procedure has been developed to isolate DNA from the ectomycorrhizae of Tuber spp. for use in PCR experiments. The method described is fast and sensitive and can overcome the amplification problems that can arise in the presence of inhibitors. For this reason it can be used to type ectomycorrhizae even starting from a single root tip and make mycorrhizae identification much more rapid.     

Angiopoietin decoy secreted at tumor site impairs tumor growth and metastases by inducing local inflammation and altering neoangiogenesis

The extracellular domain of the receptor tyrosine kinase Tie2/TEK (exTEK) has been used as an angiopoietin decoy to study the role of angiopoietins in the tumor–host interactions, using a syngeneic model of experimental metastases and subcutaneous tumor. Soluble exTEK secreted by transfected tumor cells inhibited HUVECs from forming tubes in Matrigel. ExTEK-transfected C26 colon carcinoma and TS/A mammary tumor cells displayed reduced growth rate when injected subcutaneously, and reduced ability to form experimental metastases when injected intravenously. Immunohistochemical analysis of tumors and metastases showed increased leukocytes infiltration and signs of inflammation in exTEK-secreting compared to parental tumor, as well as impairment in neo-vessel growth and organization. However, while neoangiogenesis eventually rescued in the subcutis, it failed to organize in the experimental metastases of exTEK-secreting tumor, contributing to the hampering of metastatic growth and to increased mice survival. The reactive infiltrate of C26TEK contained a different percentage of leukocytes and was responsible for the tumor inhibition. In fact, leukopenia induced by -irradiation of recipient mice or injection into interferon gamma (IFN-) gene knockout (GKO) mice resulted in reduced mouse survival and an increased number of lung metastases. On the other hand, interleukin (IL)-12 treatment prolonged the survival of mice bearing subcutaneous C26TEK but not of those bearing lung metastases, suggesting that IL-12 could exert further antiangiogenic effects at the site where the tumor can restore neoangiogenesis. These results show in vivo that reduced angiopoietin availability at the tumor site induces a local inflammatory response and impairment of neoangiogenesis which act synergistically to limit tumor growth and metastasis.Abbreviations AEC amino-ethylcarbazole - ELISA enzyme-linked immunosorbent assay - HRP horseradish peroxidase - HUVEC human umbilical vascular endothelial cell - i.v. intravenous - s.c. subcutaneous - TBS Tris-HCl buffered solution     

Changes in public order after the opening of a medically supervised safer injecting facility for illicit injection drug users

Background

North America''s first medically supervised safer injecting facility for illicit injection drug users was opened in Vancouver on Sept. 22, 2003. Although similar facilities exist in a number of European cities and in Sydney, Australia, no standardized evaluations of their impact have been presented in the scientific literature.

Methods

Using a standardized prospective data collection protocol, we measured injection-related public order problems during the 6 weeks before and the 12 weeks after the opening of the safer injecting facility in Vancouver. We measured changes in the number of drug users injecting in public, publicly discarded syringes and injection-related litter. We used Poisson log-linear regression models to evaluate changes in these public order indicators while considering potential confounding variables such as police presence and rainfall.

Results

In stratified linear regression models, the 12-week period after the facility''s opening was independently associated with reductions in the number of drug users injecting in public (p < 0.001), publicly discarded syringes (p < 0.001) and injection-related litter (p < 0.001). The predicted mean daily number of drug users injecting in public was 4.3 (95% confidence interval [CI] 3.5–5.4) during the period before the facility''s opening and 2.4 (95% CI 1.9–3.0) after the opening; the corresponding predicted mean daily numbers of publicly discarded syringes were 11.5 (95% CI 10.0–13.2) and 5.4 (95% CI 4.7–6.2). Externally compiled statistics from the city of Vancouver on the number of syringes discarded in outdoor safe disposal boxes were consistent with our findings.

Interpretation

The opening of the safer injecting facility was independently associated with improvements in several measures of public order, including reduced public injection drug use and public syringe disposal.Many cities are experiencing epidemics of bloodborne diseases as a result of illicit injection drug use,^1,2,3 and drug overdoses have become a leading cause of death in many urban areas.^4,5,6 Public drug use also plagues many inner city neighbourhoods, and the unsafe disposal of syringes in these settings is a major community concern.^{7,8,9,10,11,12,13}In over 2 dozen European cities and, more recently, in Sydney, Australia, medically supervised safer injecting facilities, where injection drug users (IDUs) can inject previously obtained illicit drugs under the supervision of medical staff, have been established in an effort to reduce the community and public health impacts of illicit drug use.¹⁴ Inside these facilities IDUs are typically provided with sterile injecting equipment, emergency care in the event of overdose, as well as primary care services and referral to addiction treatment.^13,15 Although anecdotal reports have suggested that such sites may improve public order,¹² reduce the number of deaths from overdose¹⁶ and improve access to care,¹⁷ no standardized evaluations of their impact are available in the scientific literature.¹⁸On Sept. 22, 2003, health officials in Vancouver opened a government-sanctioned safer injecting facility as pilot project. The facility, the first in North America, is centrally located in Vancouver''s Downtown Eastside, which is the most impoverished urban neighbourhood in Canada and home to well-documented overdose and HIV epidemics among the estimated 5000 IDUs who reside there.^19,20 Federal approval for the 3-year project was granted on the condition that the health and social impacts of the facility be rigorously evaluated. Although evaluation of the facility''s impact on certain outcomes (e.g., HIV incidence) is ongoing and will take several years, it is now possible to examine the impacts of the site on public order. Therefore, we conducted this study to test the hypothesis that changes in improperly discarded syringes and public drug use would be observed after the opening of the safer injecting facility.