Soil metabolomics: Deciphering underground metabolic webs in terrestrial ecosystems.

Soil metabolomics is an emerging approach for profiling diverse small molecule metabolites, i.e., metabolomes, in the soil. Soil metabolites, including fatty acids, amino acids, lipids, organic acids, sugars, and volatile organic compounds, often contain essential nutrients such as nitrogen, phosphorus, and sulfur and are directly linked to soil biogeochemical cycles driven by soil microorganisms. This paper presents an overview of methods for analyzing soil metabolites and the state-of-the-art of soil metabolomics in relation to soil nutrient cycling. We describe important applications of metabolomics in studying soil carbon cycling and sequestration, and the response of soil organic pools to changing environmental conditions. This includes using metabolomics to provide new insights into the close relationships between soil microbiome and metabolome, as well as responses of soil metabolome to plant and environmental stresses such as soil contamination. We also highlight the advantage of using soil metabolomics to study the biogeochemical cycles of elements and suggest that future research needs to better understand factors driving soil function and health.

Community composition and physiological plasticity control microbial carbon storage across natural and experimental soil fertility gradients.

Many microorganisms synthesise carbon (C)-rich compounds under resource deprivation. Such compounds likely serve as intracellular C-storage pools that sustain the activities of microorganisms growing on stoichiometrically imbalanced substrates, making them potentially vital to the function of ecosystems on infertile soils. We examined the dynamics and drivers of three putative C-storage compounds (neutral lipid fatty acids [NLFAs], polyhydroxybutyrate [PHB], and trehalose) across a natural gradient of soil fertility in eastern Australia. Together, NLFAs, PHB, and trehalose corresponded to 8.5-40% of microbial C and 0.06-0.6% of soil organic C. When scaled to "structural" microbial biomass (indexed by polar lipid fatty acids; PLFAs), NLFA and PHB allocation was 2-3-times greater in infertile soils derived from ironstone and sandstone than in comparatively fertile basalt- and shale-derived soils. PHB allocation was positively correlated with belowground biological phosphorus (P)-demand, while NLFA allocation was positively correlated with fungal PLFA : bacterial PLFA ratios. A complementary incubation revealed positive responses of respiration, storage, and fungal PLFAs to glucose, while bacterial PLFAs responded positively to PO43-. By comparing these results to a model of microbial C-allocation, we reason that NLFA primarily served the "reserve" storage mode for C-limited taxa (i.e., fungi), while the variable portion of PHB likely served as "surplus" C-storage for P-limited bacteria. Thus, our findings reveal a convergence of community-level processes (i.e., changes in taxonomic composition that underpin reserve-mode storage dynamics) and intracellular mechanisms (e.g., physiological plasticity of surplus-mode storage) that drives strong, predictable community-level microbial C-storage dynamics across gradients of soil fertility and substrate stoichiometry.

Covalent Targeting of Splicing in T Cells.

Despite significant interest in therapeutic targeting of splicing, few chemical probes are available for the proteins involved in splicing. Here, we show that elaborated stereoisomeric acrylamide chemical probe EV96 and its analogues lead to a selective T cell state-dependent loss of interleukin 2-inducible T cell kinase (ITK) by targeting one of the core splicing factors SF3B1. Mechanistic investigations suggest that the state-dependency stems from a combination of differential protein turnover rates and availability of functional mRNA pools that can be depleted due to extensive alternative splicing. We further introduce a comprehensive list of proteins involved in splicing and leverage both cysteine- and protein-directed activity-based protein profiling (ABPP) data with electrophilic scout fragments to demonstrate covalent ligandability for many classes of splicing factors and splicing regulators in primary human T cells. Taken together, our findings show how chemical perturbation of splicing can lead to immune state-dependent changes in protein expression and provide evidence for the broad potential to target splicing factors with covalent chemistry.

Sub-ppm gas phase Raman spectroscopy in an anti-resonant hollow core fiber.

We demonstrate recent progress in the development of a Raman gas sensor using a single cladding ring anti-resonant hollow core micro-structured optical fiber (HC-ARF) and a low power pump source. The HC-ARF was designed specifically for low attenuation and wide bandwidth in the visible spectral region and provided low loss at both the pump wavelength (532 nm) and Stokes wavelengths up to a Raman shift of 5000 cm-1. A novel selective core pressurization scheme was also implemented to further reduce the confinement loss, improving the Raman signal enhancement by a factor of 1.9 compared to a standard fiber filling scheme. By exploiting longer lengths of fiber, direct detection of both methane and hydrogen at concentrations of 5 and 10 ppm respectively is demonstrated and a noise equivalent limit-of-detection of 0.15 ppm is calculated for methane.

Oxidized thioredoxin-1 restrains the NLRP1 inflammasome.

The danger signals that activate the NLRP1 inflammasome have not been established. Here, we report that the oxidized, but not the reduced, form of thioredoxin-1 (TRX1) binds to NLRP1. We found that oxidized TRX1 associates with the NACHT-LRR region of NLRP1 in an ATP-dependent process, forming a stable complex that restrains inflammasome activation. Consistent with these findings, patient-derived and ATPase-inactivating mutations in the NACHT-LRR region that cause hyperactive inflammasome formation interfere with TRX1 binding. Overall, this work strongly suggests that reductive stress, the cellular perturbation that will eliminate oxidized TRX1 and abrogate the TRX1-NLRP1 interaction, is a danger signal that activates the NLRP1 inflammasome.

Core Collections: Is There Any Value for Cotton Breeding?

Global plant breeding activities are reliant on the available genetic variation held in extant varieties and germplasm collections. Throughout the mid- to late 1900s, germplasm collecting efforts were prioritized for breeding programs to archive precious material before it disappeared and led to the development of the numerous large germplasm resources now available in different countries. In recent decades, however, the maintenance and particularly the expansion of these germplasm resources have come under threat, and there has been a significant decline in investment in further collecting expeditions, an increase in global biosecurity restrictions, and restrictions placed on the open exchange of some commercial germplasm between breeders. The large size of most genebank collections, as well as constraints surrounding the availability and reliability of accurate germplasm passport data and physical or genetic characterization of the accessions in collections, limits germplasm utilization by plant breeders. To overcome these constraints, core collections, defined as a representative subset of the total germplasm collection, have gained popularity. Core collections aim to increase germplasm utilization by containing highly characterized germplasm that attempts to capture the majority of the variation in a whole collection. With the recent availability of many new genetic tools, the potential to unlock the value of these resources can now be realized. The Commonwealth Scientific and Industrial Research Organisation (CSIRO) cotton breeding program supplies 100% of the cotton cultivars grown in Australia. The program is reliant on the use of plant genetic resources for the development of improved cotton varieties to address emerging challenges in pest and disease resistance as well as the global changes occurring in the climate. Currently, the CSIRO germplasm collection is actively maintained but underutilized by plant breeders. This review presents an overview of the Australian cotton germplasm resources and discusses the appropriateness of a core collection for cotton breeding programs.

Mitigation of Galvanic Corrosion in Bolted Joint of AZ31B and Carbon Fiber-Reinforced Composite Using Polymer Insulation.

The use of polymer insulation to mitigate galvanic corrosion was examined for bolted joints of AZ31B Mg alloy and carbon fiber-reinforced composite. To assess the corrosion behaviors of bolted joints with and without polymer insulation, solution immersion and salt spray exposure (ASTM B117) tests were conducted, and the corrosion depths and volumes were determined for the joint specimens after the tests. The polymer-insulated bolted joints exhibited much lower corrosion depths and volumes, highlighting the effective mitigation of galvanic corrosion. The reductions of joint strength in the post-corrosion joint specimens were relatively small (up to ~10%) in the polymer-insulated group but greater (up to 90%) in the group with no insulation. Cross-sectional characterization of post-corrosion joints with polymer insulation revealed local pits developed on AZ31B under galvanic influence, indicating that limited galvanic attack (that did not decrease the joining integrity significantly) could still occur during a long salt spray exposure (~1264 h) owing to the permeation of an aqueous corrosive medium.

The contribution of PIP2-type aquaporins to photosynthetic response to increased vapour pressure deficit.

The roles of different plasma membrane aquaporins (PIPs) in leaf-level gas exchange of Arabidopsis thaliana were examined using knockout mutants. Since multiple Arabidopsis PIPs are implicated in CO2 transport across cell membranes, we focused on identifying the effects of the knockout mutations on photosynthesis, and whether they are mediated through the control of stomatal conductance of water vapour (gs), mesophyll conductance of CO2 (gm), or both. We grew Arabidopsis plants in low and high humidity environments and found that the contribution of PIPs to gs was larger under low air humidity when the evaporative demand was high, whereas any effect of a lack of PIP function was minimal under higher humidity. The pip2;4 knockout mutant had 44% higher gs than wild-type plants under low humidity, which in turn resulted in an increased net photosynthetic rate (Anet). We also observed a 23% increase in whole-plant transpiration (E) for this knockout mutant. The lack of functional plasma membrane aquaporin AtPIP2;5 did not affect gs or E, but resulted in homeostasis of gm despite changes in humidity, indicating a possible role in regulating CO2 membrane permeability. CO2 transport measurements in yeast expressing AtPIP2;5 confirmed that this aquaporin is indeed permeable to CO2.

Multiplex digital spatial profiling of proteins and RNA in fixed tissue.

Digital Spatial Profiling (DSP) is a method for highly multiplex spatial profiling of proteins or RNAs suitable for use on formalin-fixed, paraffin-embedded (FFPE) samples. The approach relies on (1) multiplexed readout of proteins or RNAs using oligonucleotide tags; (2) oligonucleotide tags attached to affinity reagents (antibodies or RNA probes) through a photocleavable (PC) linker; and (3) photocleaving light projected onto the tissue sample to release PC oligonucleotides in any spatial pattern across a region of interest (ROI) covering 1 to ~5,000 cells. DSP is capable of single-cell sensitivity within an ROI using the antibody readout, with RNA detection feasible down to ~600 individual mRNA transcripts. We show spatial profiling of up to 44 proteins and 96 genes (928 RNA probes) in lymphoid, colorectal tumor and autoimmune tissues by using the nCounter system and 1,412 genes (4,998 RNA probes) by using next-generation sequencing (NGS). DSP may be used to profile not only proteins and RNAs in biobanked samples but also immune markers in patient samples, with potential prognostic and predictive potential for clinical decision-making.

Evaluation of a novel extended automated particle-based multi-analyte assay for the detection of autoantibodies in the diagnosis of primary biliary cholangitis.

Background: Anti-mitochondrial autoantibodies (AMA) detected by indirect immunofluorescence (IIF) on rodent tissues are the diagnostic marker of primary biliary cholangitis (PBC). However, up to 15% of patients with PBC are AMA-negative by IIF. In the effort to close the serological gap and improve the diagnostic sensitivity of PBC testing, recently, novel autoantibodies specific for PBC, such as kelch-like 12 (KLHL12, KLp epitope) and hexokinase 1 (HK1) have been described. In this study, we evaluated the autoantibody profile in a large cohort of PBC patients and in patients with other liver disease, including anti-HK1 and anti-KLp autoantibodies. Methods: Sera of 194 PBC patients (126 AMA-IIF-positive and 68 AMA-IIF-negative) and 138 disease controls were tested for a panel of PBC-specific antibodies (MIT3, sp100, gp210, HK1, KLp) using a new automated particle-based multi-analyte technology (PMAT) assay on the Aptiva instrument (Inova). Results: Selecting a cutoff yielding a specificity of >95% for all the markers, the sensitivity for anti-MIT3, anti-sp100, anti-gp210, anti-HK1 and anti-KLp in the PBC AMA-IIF-negative cohort was 20.6%, 16.2%, 23.5%, 22.0%, 17.6 and 13.2%, respectively. Six out of the 68 (8.8%) AMA-IIF negative sera were positive for anti-HK1 or anti-KLp alone. Using these new markers in addition to anti-MIT3, anti-sp100 and anti-gp210, the overall sensitivity in this cohort of AMA-IIF-negative patients increased from 53% to 61.8%, reducing the serological gap in AMA-negative PBC patients. Conclusions: PBC antibody profiling, made possible by the new Aptiva-PMAT technology, allows recognition of a higher number of AMA-negative PBC patients than conventional immunoassays and may represent a useful tool to evaluate the prognostic significance of autoantibody association in PBC patients.

Effects of ferrule and diameter of parallel cast post and core on fracture resistance / Efeitos da férula e diâmetro de núcleos metálicos paralelos na resistência a fratura

Objective: The aim of this study was to evaluate the effects of using different diameters of parallel cast posts with, or without ferrule, on the overall fracture resistance of Cast Post and Core (CPC). Material and Methods: Forty (40) endodontically treated human maxillary central incisors were divided into four groups (n=10): [F1] 1.0 mm diameter post with ferrule; [NF1] 1.0 mm diameter cast post without ferrule; [F1.5] 1.5 mm diameter cast post with ferrule; [NF1.5] 1.5 mm diameter post without ferrule. For all teeth, the post space (9.0 mm, in depth) was prepared using ParaPostTM drill. CPC using base metal alloy were fabricated and were cemented using resin modified glass ionomer (RMGI) cement along with the Porcelain Fused to Metal (PFM) crowns. A universal testing machine (Instron) was used to apply horizontal force perpendicular to the long axis of the tooth at the center of lingual surface, until catastrophic failure. Data was submitted to two-way ANOVA and Scheffé tests (P<0.05). Results: Both post diameter and ferrule statistically affected the maximum load at fracture (P=0.004 and P=0.013, respectively). The highest mean values were observed for samples with ferrule and wider post size (490N), while the lowest were observed for samples without ferrule and narrower post size (254N). There was no relationship between the presence of a ferrule and post size (P=0.937). Conclusion: For endodontically treated teeth with no ferrule, a wider-diameter cast post increased fracture resistance of a CPC and PFM crown procedure. (AU)

Objetivo: O objetivo do presente estudo foi avaliar os efeitos de diferentes diâmetros de núcleos metálicos paralelos (com ou sem férula) na resistência a fratura do procedimento restaurador. Material e Métodos: Quarenta (40) incisivos centrais superiores humanos foram tratados endodonticamente e divididos em quarto grupos (n=10): [F1] Diâmetro de 1.0 mm, com férula; [NF1] Diâmetro de 1.0 mm, sem férula; [F1.5] Diâmetro de 1.5 mm, com férula; [NF1.5] Diâmetro de 1.5 mm, sem férula. Para todos os dentes, o espaço foi preparado para o núcleo (9.0 mm, em comprimento) utilizando brocas do ParaPostTM. Os núcleos metálicos e as coroas metalocerâmicas fabricadas foram cimentados utilizando-se cimento de ionômero de vidro modificado por resina. Uma máquina de ensaios universal (Instron) foi utilizada para aplicar uma força horizontal perpendicular ao longo eixo do dente, no centro da face lingual, até falha catastrófica. Os dados foram analisados através de análise de variância de dois fatores e teste de Scheffé (p<0.05). Resultados: O diâmetro do núcleo e a presença (ou ausência) de férula afteram estatiscamente a resistência máxima a fratura do procedimento (P=0.004 e P=0.013, respectivamente). Os maiores valores foram observados para amostras com férula e de maior diâmetro (490N), enquanto os menores valores foram observados para amostras sem férula e de menor diâmetro (254N). Conclusão: Para dentes tratados endodondicamente, com férula, um núcleo de maior diâmetro aumentou a resistência a fratura de procedimentos restauradores envolvendo coroas metalocerâmicas cimentadas sobre núcleos metálicos fundidos. (AU)

Lysozyme depolymerization of photo-activated chitosan adhesive films.

Effective tissue bioadhesion of rose bengal-chitosan films can be achieved by photoactivation using a green laser. In this study, lysozyme was incorporated in these films to enhance the rate of depolymerization and assess the laser impact on lysozyme. The lysozyme loaded films exhibited a 21% mass loss after 4 weeks implantation in rats while control films (without lysozyme) had only 7% mass loss. Capillary electrophoresis-mass spectroscopy showed that chitosan degraded into monomers and oligomers of glucosamine and N-acetyl-glucosamine. Irradiation with laser did not affect the depolymerization of adhesive by lysozyme suggesting that the inclusion of lysozyme in the bioadhesive is a viable technique for tailoring the depolymerization.

Implications of the mesophyll conductance to CO2 for photosynthesis and water-use efficiency during long-term water stress and recovery in two contrasting Eucalyptus species.

Water stress (WS) slows growth and photosynthesis (A(n)), but most knowledge comes from short-time studies that do not account for longer term acclimation processes that are especially relevant in tree species. Using two Eucalyptus species that contrast in drought tolerance, we induced moderate and severe water deficits by withholding water until stomatal conductance (g(sw)) decreased to two pre-defined values for 24 d, WS was maintained at the target g(sw) for 29 d and then plants were re-watered. Additionally, we developed new equations to simulate the effect on mesophyll conductance (g(m)) of accounting for the resistance to refixation of CO(2). The diffusive limitations to CO(2), dominated by the stomata, were the most important constraints to A(n). Full recovery of A(n) was reached after re-watering, characterized by quick recovery of gm and even higher biochemical capacity, in contrast to the slower recovery of g(sw). The acclimation to long-term WS led to decreased mesophyll and biochemical limitations, in contrast to studies in which stress was imposed more rapidly. Finally, we provide evidence that higher gm under WS contributes to higher intrinsic water-use efficiency (iWUE) and reduces the leaf oxidative stress, highlighting the importance of gm as a target for breeding/genetic engineering.

The role of mesophyll conductance in the economics of nitrogen and water use in photosynthesis.

A recent resurgence of interest in formal optimisation theory has begun to improve our understanding of how variations in stomatal conductance and photosynthetic capacity control the response of whole plant photosynthesis and growth to the environment. However, mesophyll conductance exhibits similar variation and has similar impact on photosynthesis as stomatal conductance; yet, the role of mesophyll conductance in the economics of photosynthetic resource use has not been thoroughly explored. In this article, we first briefly summarise the knowledge of how mesophyll conductance varies in relation to environmental factors that also affect stomatal conductance and photosynthetic capacity, and then we use a simple analytical approach to begin to explore how these important controls on photosynthesis should mutually co-vary in a plant canopy in the optimum. Our analysis predicts that when either stomatal or mesophyll conductance is limited by fundamental biophysical constraints in some areas of a canopy, e.g. reduced stomatal conductance in upper canopy leaves due to reduced water potential, the other of the two conductances should increase in those leaves, while photosynthetic capacity should decrease. Our analysis also predicts that if mesophyll conductance depends on nitrogen investment in one or more proteins, then nitrogen investment should shift away from Rubisco and towards mesophyll conductance if hydraulic or other constraints cause chloroplastic CO2 concentration to decline. Thorough exploration of these issues awaits better knowledge of whether and how mesophyll conductance is itself limited by nitrogen investment, and about how these determinants of photosynthetic CO2 supply and demand co-vary among leaves in real plant canopies.

Effects of drought on mesophyll conductance and photosynthetic limitations at different tree canopy layers.

In recent years, many studies have focused on the limiting role of mesophyll conductance (gm ) to photosynthesis (An ) under water stress, but no studies have examined the effect of drought on gm through the forest canopy. We investigated limitations to An on leaves at different heights in a mixed adult stand of sessile oak (Quercus petraea) and beech (Fagus sylvatica) trees during a moderately dry summer. Moderate drought decreased An of top and lowest beech canopy leaves much more than in leaves located in the mid canopy; whereas in oak, An of the lower canopy was decreased more than in sunlit leaves. The decrease of An was probably not due to leaf-level biochemistry given that VCmax was generally unaffected by drought. The reduction in An was instead associated with reduction in stomatal and mesophyll conductances. Drought-induced increases in stomatal limitations were largest in leaves from the top canopy, whereas drought-induced increases in mesophyll limitations were largest in leaves from the lowest canopy. Sensitivity analysis highlighted the need to decompose the canopy into different leaf layers and to incorporate the limitation imposed by gm when assessing the impact of drought on the gas exchange of tree canopies.

Quaternary ammonium compounds can be abundant in some soils and are taken up as intact molecules by plants.

Studies of organic nitrogen (N) cycling and uptake by plants have focused on protein amino acids, but the soil solution includes organic N compounds from many other compound classes. The two aims of this study were to characterize the 30-50 most abundant molecules of small (< 250 Da), nonpeptide organic N in the soil solution from six soils, and to determine if two ecologically disparate species (nonmycorrhizal Banksia oblongifolia and mycorrhizal Triticum aestivum) have the ability to take up intact molecules of three quaternary ammonium compounds (betaine, carnitine and acetyl-carnitine). Protein amino acids were dominant components of the pool of small nonpeptide organic N in all soils. The most abundant other compound classes were quaternary ammonium compounds (1-28% of nonpeptide small organic N) and nonprotein amino acids (3-19% of nonpeptide small organic N). B. oblongifolia and T. aestivum took up intact quaternary ammonium compounds from dilute hydroponic solution, while T. aestivum growing in field soil took up intact quaternary ammonium compounds injected into soil. Results of this study show that the pool of organic N in soil is more diverse and plants have an even broader palate than is suggested by most of the literature on organic N.

Mesophyll diffusion conductance to CO2: an unappreciated central player in photosynthesis.

Mesophyll diffusion conductance to CO(2) is a key photosynthetic trait that has been studied intensively in the past years. The intention of the present review is to update knowledge of g(m), and highlight the important unknown and controversial aspects that require future work. The photosynthetic limitation imposed by mesophyll conductance is large, and under certain conditions can be the most significant photosynthetic limitation. New evidence shows that anatomical traits, such as cell wall thickness and chloroplast distribution are amongst the stronger determinants of mesophyll conductance, although rapid variations in response to environmental changes might be regulated by other factors such as aquaporin conductance. Gaps in knowledge that should be research priorities for the near future include: how different is mesophyll conductance among phylogenetically distant groups and how has it evolved? Can mesophyll conductance be uncoupled from regulation of the water path? What are the main drivers of mesophyll conductance? The need for mechanistic and phenomenological models of mesophyll conductance and its incorporation in process-based photosynthesis models is also highlighted.

Linking Global Youth Tobacco Survey (GYTS) data to tobacco control policy in Turkey--2003 and 2009.

OBJECTIVE: The purpose of this paper is to use data from the Global Youth Tobacco Survey (GYTS) conducted in Turkey in 2003 and 2009 to examine changes in tobacco use and important tobacco control measures. METHODS: The GYTS were conducted in grades 7-9 in 2003 and 7-10 in 2009 in Turkey. Data in this paper are limited to 13 to 15 year old students. A total of 15,957 students from 202 schools participated in 2003 and 5,054 students from 69 schools participated in 2009. The overall response rate was 92.1% in 2003 and 87.5% in 2009. RESULTS: Between 2003 and 2009 current cigarette smoking did not change significantly for either boys (9.4% to 10.2%) or girls (3.5% to 5.3%). Current cigarette smoking was higher among boys than girls in 2003 and in 2009. In 2009, half of students reported they had been exposed to second hand smoking (SHS) at home and 80% reported they had been exposed to SHS in public places. Three in ten students reported they had been exposed to pro-tobacco advertising in newspapers or magazines; one in ten had an object with a cigarette brand logo on it; and 7% had been offered free cigarettes by a cigarette company representative. Two-thirds of current cigarette smokers reported that they wanted to stop smoking; and almost two-thirds had been taught in school in the past year about the dangers of smoking. CONCLUSION: Passing and implementing the Law No. 4207 on Prevention of Hazards of Tobacco Products, ratifying the World Health Organization Framework Convention on Tobacco Control (WHO FCTC), raising tax on tobacco, and requiring pictorial warning labels were important steps forward for tobacco control in Turkey. However, as to the tobacco control much work yet to be accomplished including developing an effective enforcement plan for all tobacco control efforts.

Effect of policy changes on cigarette sales: the case of Turkey.

BACKGROUND: In 1996, Turkey made tobacco control a health priority. The tobacco control effort was extended in July 2009 with the expansion of the smoke-free law to include all enclosed workplaces and public places and, in January 2010, with a 20% increase in the Special Consumption Tax on Tobacco. METHODS: Sales data were averaged, by month, for the period January 2005 through June 2009 to establish an 'expected' monthly sales pattern. This was the period when no new tobacco control measures were implemented. The overall monthly average was then calculated for the same period. The expected monthly sales pattern was then graphed against the overall monthly sales average to delineate a seasonal sales pattern that was used to evaluate the divergence of actual monthly sales from the 'expected' pattern. RESULTS: A distinct seasonal pattern was found with sales above average from May through August. Comparison of actual cigarette sales to the 'expected' monthly sales pattern following the implementation of the expanded smoke-free law in July resulted in a 5.2% decrease. Cigarettes sales decreased by 13.6% following the January 2010 Special Consumption Tax. Since the implementation of the expanded smoke-free law in July 2009 and the tax increase in January 2010, cigarette sales in Turkey decreased by 10.7%. CONCLUSION: The effect of recent Turkish tobacco control policies could contribute to a reduction in the number of premature deaths related to tobacco use. Evidence has shown that periodic tax increases and strong enforcement of all tobacco control policies are essential to further decrease tobacco consumption.

Tobacco use, exposure to secondhand smoke, and cessation counseling among health professions students: greek data from the global health professions student Survey (GHPSS).

We conducted the GHPSS (Global Health Professions Student Survey) to obtain information regarding health profession students' smoking habits and perceptions, exposure to secondhand smoke (SHS) as well as level of knowledge and training on tobacco use and smoking cessation counseling. GHPSS is a survey for third-year students in the following fields: health visitors, dentistry, medicine, nursing and/or pharmacy. The highest tobacco use prevalence rate and exposure to SHS were recorded among health visitor students with 46.4% and 33.3% respectively. The majority of the respondents believed that their profession serves as a role model for their patients. Formal training on cessation counseling ranged between 10.7% for health visitor students to 22.4% for nursing students. The relatively high percentage of health profession students who currently smoke and the alarmingly high percentage of those exposed to SHS indicate lack of concerted efforts for implementation and effective enforcement of the anti-tobacco policy measures. Despite its significance, formal training on cessation counseling for students is strikingly low. These results indicate the urgent need to train health professional students on tobacco cessation counseling and educate them on the dangers of tobacco use, SHS and the positively influential role they can play to affect their patients' smoking habits.