bluuebunny/crossref_metadata_2025 huggingface dataset:
Epidemiology and characterization ofStaphylococcus epidermidisisolates from humans, raw bovine milk and a dairy plant
Authors: JAGLIC Z. , MICHU E. , HOLASOVA M. , VLKOVA H. , BABAK V. , KOLAR M. , BARDON J. , SCHLEGELOVA J.
Published: October 2009

Geographically relatedStaphylococcus epidermidisisolates from human patients (n=30), dairy farms (farmers and individual raw milk from cattle,n=36) and a dairy plant (n=55) were examined for epidemiological relatedness by pulsed-field gel electrophoresis and, usingin vitromethods, for the ability to produce biofilm and antimicrobial resistance. Methicillin-resistant isolates (MRSE) were also identified and characterized. Isolates from farmers and dairy cattle were found to be genetically related, while isolates from human patients were highly diverse. Some dairy plant isolates (18·2%) were closely related to those from dairy farms. Biofilm production and resistance to antimicrobial agents were most typical for isolates from human patients, of which 76·7% were MRSE. Methicillin resistance was also widespread in farm-related isolates (61·1%). This study indicates the possible transmission ofS. epidermidisbetween cattle and farmers. Dairy products were not proven to be an important source of either human infections or methicillin-resistant strains.
The epidemiology of primary amoebic meningoencephalitis in the USA, 1962–2008
Authors: YODER J. S. , EDDY B. A. , VISVESVARA G. S. , CAPEWELL L. , BEACH M. J.
Published: October 2009

Naegleria fowleri, a free-living, thermophilic amoeba ubiquitous in the environment, causes primary amoebic meningoencephalitis (PAM), a rare but nearly always fatal disease of the central nervous system. While case reports of PAM have been documented worldwide, very few individuals have been diagnosed with PAM despite the vast number of people who have contact with fresh water whereN. fowlerimay be present. In the USA, 111 PAM case-patients have been prospectively diagnosed, reported, and verified by state health officials since 1962. Consistent with the literature, case reports reveal thatN. fowleriinfections occur primarily in previously healthy young males exposed to warm recreational waters, especially lakes and ponds, in warm-weather locations during summer months. The annual number of PAM case reports varied, but does not appear to be increasing over time. Because PAM is a rare disease, it is challenging to understand the environmental and host-specific factors associated with infection in order to develop science-based, risk reduction messages for swimmers.
Emergence and disappearance of W135 meningococcal disease
Authors: WILDER-SMITH A. , CHOW A. , GOH K.-T.
Published: October 2009

W135 meningococcal disease was imported into Singapore in 2000 via Hajj pilgrims. Previous studies have showed sustained carriage of W135 with the potential for further transmission within communities. We therefore set out to determine whether W135 meningococcal disease would become endemic in Singapore after its introduction in 2000. Cases occurred until 2003, but no further cases have been reported since 2004.
Temporal and farm-management-associated variation in the faecal-pat prevalence ofCampylobacter jejuniin ruminants
Authors: GROVE-WHITE D. H. , LEATHERBARROW A. J. H. , CRIPPS P. J. , DIGGLE P. J. , FRENCH N. P.
Published: October 2009

In a 2-year longitudinal study of adult animals on 15 dairy farms and four sheep farms in Lancashire, UK.C. jejuniwas isolated from all farms, although not on every occasion. Faecal samples were collected and cultured using standard techniques for isolation ofCampylobacter. Assignment to species was via PCR assays. Peak prevalence ofC. jejuniin both cattle and sheep was observed during the summer and in cattle this apparent seasonality was associated with grazing pasture [odds ratio (OR) 2·14], while in sheep it was independent of grazing. Increased prevalence was associated with increased milk yield (OR 1·05) and herd size (OR 1·01) in dairy cattle, and with increased stocking density (OR 1·29) and pasture quality (OR 2·16) in sheep. There was considerable variation in prevalence between farms but no evidence of large-scale spatial variation. The association betweenC. jejuniprevalence and diet in dairy cattle deserves further investigation.
Interannual variations in the Atlantic meridional overturning circulation and its relationship with the net northward heat transport in the South Atlantic
Authors: Dong Shenfu , Garzoli Silvia , Baringer Molly , Meinen Christopher , Goni Gustavo
Published: October 2009

Variability of the Atlantic Meridional Overturning Circulation (AMOC) and its effect on the net northward heat transport (NHT) in the South Atlantic are examined using a trans‐basin expendable bathythermograph (XBT) high‐density line at 35°S (AX18). The time‐mean AMOC is 17.9 ± 2.2 Sv during 2002–2007. Although the geostrophic transport dominates the time‐mean AMOC, both geostrophic and Ekman transports are important in explaining the AMOC variability. The contributions of geostrophic and Ekman transports to the AMOC show annual cycles, but they are out of phase, resulting in weak seasonal variability of the AMOC. The NHT variability is significantly correlated with the AMOC, where a 1 Sv increase in the AMOC would yield a 0.05 ± 0.01 PW increase in the NHT. Partition of transport into the western and eastern boundaries and interior suggests that, to quantify changes in the AMOC and NHT, it is critical to monitor all three regions.
Gravity‐driven water exchange between streams and hyporheic zones
Authors: Boano F. , Poggi D. , Revelli R. , Ridolfi L.
Published: October 2009

The exchange of water and nutrients between rivers and hyporheic zones has been recognized as a very important process for the stream ecosystem. This water exchange is generally explained by pressure gradients on the riverbed that are induced by fluvial geomorphological features or by turbulent coherent structures. In this work we discuss a different exchange mechanism due to density gradients between the in‐stream and the hyporheic water. We present laboratory results that show how weak density gradients are able to induce significant hyporheic fluxes. This gravity‐induced exchange is expected to play a major role in streams with low‐permeability sediments or with small topographic features.
Relative contribution of temperature and salinity to ocean acoustic reflectivity
Authors: Sallarès V. , Biescas B. , Buffett G. , Carbonell R. , Dañobeitia J. J. , Pelegrí J. L.
Published: October 2009

Marine seismic data display laterally coherent reflectivity from the water column that is attributed to fine‐scale oceanic layering. The amplitude of the different reflections is the expression of acoustic impedance contrasts between neighbouring water masses, and therefore water reflectivity maps the ocean's vertical sound speed and density (i.e., temperature and salinity) variations. Here we determine the relative contribution of each parameter by computing the temperature and salinity partial derivatives of sound speed and density, and using them to estimate reflection coefficients from a real oceanographic dataset. The results show that the mean contribution of density variations is 5–10%, while 90–95% is due to sound speed variations. On average, 80% of reflectivity comes from temperature contrasts. Salinity contribution averages 20%, but it is highly variable and reaches up to 40% in regions prone to diffusive convection such as the top of the Mediterranean Undercurrent in the Gulf of Cadiz.
Diurnal variation in summer precipitation over the central Tibetan Plateau
Authors: Singh Prasamsa , Nakamura Kenji
Published: October 2009

The diurnal cycle of rainfall over the central Tibetan Plateau was investigated by examining data acquired by the Tropical Rainfall Measuring Mission Precipitation Radar during the summer monsoon season (June–August) from 1998–2007. High‐spatial‐resolution data (∼5 km × 5 km) were used to identify the role of complex topographic features of the plateau. Diurnal variations in rain rate, frequency of rain, conditional rain rate, and storm‐height were analyzed on a monthly basis to determine the characteristics of precipitation. The results are interpreted as precipitation characteristics in a semiarid region with weak prevailing winds. Distinct diurnal variation was seen over hilly regions, valleys, and lakes. Precipitation activity over the hilly region is generally strongest during the late afternoon. But in contrast, valleys and lakes show dominant late‐evening peaks, and a secondary morning rainfall peak is distinctly evident over large lakes. However, the time of peak rain rate is delayed with increasing lake size. The shift in rain peak location toward lakes and valleys also appeared clearly.
On the problem of data assimilation by means of synchronization
Authors: Szendro Ivan G. , Rodríguez Miguel A. , López Juan M.
Published: October 2009

The potential use of synchronization as a method for data assimilation is investigated in a Lorenz96 model. Data representing the reality are obtained from a Lorenz96 model with added noise. We study the assimilation scheme by means of synchronization for different noise intensities. We use a novel plot representation of the synchronization error in a phase diagram consisting of two variables: the amplitude and the width of the error after a suitable logarithmic transformation (the so‐called mean‐variance of logarithms diagram). Our main result concerns the existence of an “optimal” coupling for which the synchronization is maximal. We finally show how this allows us to quantify the degree of assimilation, providing a criterion for the selection of optimal couplings and validity of models.
Diurnal variation in vertical air motion over a tropical station, Gadanki (13.5°N, 79.2°E), and its effect on the estimation of mean vertical air motion
Authors: Uma K. N. , Rao T. Narayana
Published: October 2009

The long‐term measurements of vertical air velocity (w) made with the Indian mesosphere‐stratosphere‐troposphere (MST) radar are used to investigate the diurnal variation of w in different seasons. The effect of the diurnal variation of w and gravity wave variance on the estimation of mean w is also studied. Significant diurnal variation is observed in the vertical air motion at Gadanki with a variation larger than 6 cm s−1. This variation is, in fact, larger than the mean vertical air motion. Downdrafts are observed in the evening hours in the lower troposphere in all the seasons. A large part of this subsidence is due to the bias caused by upward propagating gravity waves, as evidenced by large hourly variance values in evening hours. In the middle and upper troposphere, the diurnal variation is dominated primarily by 12‐h oscillation, which is conspicuously present in all the seasons, albeit with different amplitudes. The 24‐h variance caused primarily by tidal and relatively long period oscillations (>2 h) and mesoscale weather disturbances is almost comparable to the variance due to short‐period gravity waves (<1 h). The variance for periods <1 h shows significant diurnal variation with peak values during afternoon‐evening. It implies that the bias in w should also have such a diurnal cycle, because the bias (downward) is directly proportional to the variance in w. Given that w and the bias sources vary considerably during the course of the day, any estimate of mean w (taken over a season/month) from data pertaining to a particular hour (hours) of the day will represent the mean w of that particular hour, but may not truly represent the seasonal/monthly mean w.
Identification of hydrated silicate minerals on Mars using MRO‐CRISM: Geologic context near Nili Fossae and implications for aqueous alteration
Authors: Ehlmann Bethany L. , Mustard John F. , Swayze Gregg A. , Clark Roger N. , Bishop Janice L. , Poulet Francois , Des Marais David J. , Roach Leah H. , Milliken Ralph E. , Wray James J. , Barnouin‐Jha Olivier , Murchie Scott L.
Published: October 2009

The Noachian terrain west of the Isidis basin hosts a diverse collection of alteration minerals in rocks comprising varied geomorphic units within a 100,000 km2 region in and near the Nili Fossae. Prior investigations in this region by the Observatoire pour l'Minéralogie, l'Eau, les Glaces, et l'Activité (OMEGA) instrument on Mars Express revealed large exposures of both mafic minerals and iron magnesium phyllosilicates in stratigraphic context. Expanding on the discoveries of OMEGA, the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) aboard the Mars Reconnaissance Orbiter (MRO) has found more spatially widespread and mineralogically diverse alteration minerals than previously realized, which represent multiple aqueous environments. Using CRISM near‐infrared spectral data, we detail the basis for identification of iron and magnesium smectites (including both nontronite and more Mg‐rich varieties), chlorite, prehnite, serpentine, kaolinite, potassium mica (illite or muscovite), hydrated (opaline) silica, the sodium zeolite analcime, and magnesium carbonate. The detection of serpentine and analcime on Mars is reported here for the first time. We detail the geomorphic context of these minerals using data from high‐resolution imagers onboard MRO in conjunction with CRISM. We find that the distribution of alteration minerals is not homogeneous; rather, they occur in provinces with distinctive assemblages of alteration minerals. Key findings are (1) a distinctive stratigraphy, in and around the Nili Fossae, of kaolinite and magnesium carbonate in bedrock units always overlying Fe/Mg smectites and (2) evidence for mineral phases and assemblages indicative of low‐grade metamorphic or hydrothermal aqueous alteration in cratered terrains. The alteration minerals around the Nili Fossae are more typical of those resulting from neutral to alkaline conditions rather than acidic conditions, which appear to have dominated much of Mars. Moreover, the mineralogic diversity and geologic context of alteration minerals found in the region around the Nili Fossae indicates several episodes of aqueous activity in multiple distinct environments.
Evolution of volcanic eruption columns
Authors: Scase M. M.
Published: October 2009

The classical steady state model for Plinian eruption columns is extended to allow the source conditions at the volcanic vent to change in time. It is shown that when the source conditions change rapidly, over time scales typically less than approximately 3–4 min, this new time‐dependent volcano model becomes appropriate. Differences between changes in source velocity and source temperature are also considered. Qualitatively similar structures are formed when either the source velocity or source temperature is reduced. A transient region is formed, characterized by a narrowing of the “top hat” eruption column radius. A first attempt to a model a Plinian eruption column, from its dynamic initiation in a volcanic eruption, is made. It is shown that the velocity at the front of the eruption column is significantly slower than the velocity at the same height in an established eruption column.
Global ecological patterns in uncultured Archaea
Authors: Auguet Jean-Christophe , Barberan Albert , Casamayor Emilio O
Published: October 2009

We have applied a global analytical approach to uncultured Archaea that for the first time reveals well-defined community patterns along broad environmental gradients and habitat types. Phylogenetic patterns and the environmental factors governing the creation and maintenance of these patterns were analyzed for c. 2000 archaeal 16S rRNA gene sequences from 67 globally distributed studies. The sequences were dereplicated at 97% identity, grouped into seven habitat types, and analyzed with both Unifrac (to explore shared phylogenetic history) and multivariate regression tree (that considers the relative abundance of the lineages or taxa) approaches. Both phylogenetic and taxon-based approaches showed salinity and not temperature as one of the principal driving forces at the global scale. Hydrothermal vents and planktonic freshwater habitats emerged as the largest reservoirs of archaeal diversity and consequently are promising environments for the discovery of new archaeal lineages. Conversely, soils were more phylogenetically clustered and archaeal diversity was the result of a high number of closely related phylotypes rather than different lineages. Applying the ecological concept of ‘indicator species’, we detected up to 13 indicator archaeal lineages for the seven habitats prospected. Some of these lineages (that is, hypersaline MSBL1, marine sediment FCG1 and freshwater plSA1), for which ecological importance has remained unseen to date, deserve further attention as they represent potential key archaeal groups in terms of distribution and ecological processes. Hydrothermal vents held the highest number of indicator lineages, suggesting it would be the earliest habitat colonized by Archaea. Overall, our approach provided ecological support for the often arbitrary nomenclature within uncultured Archaea, as well as phylogeographical clues on key ecological and evolutionary aspects of archaeal biology.
Breast Volume is an Independent Predictor of Visceral and Ectopic Fat in Premenopausal Women
Authors: Janiszewski Peter M. , Saunders Travis J. , Ross Robert
Published: October 2009

It is suggested that a large breast size among women may predict type 2 diabetes risk independent of BMI and waist circumference (WC). The purpose of this study was to determine the independent associations of breast volume with cardiometabolic risk factors and regional fat distribution. A total of 92 overweight or obese premenopausal women (age = 39.9 ± 6.8 years) underwent full‐body magnetic resonance imaging (MRI) for the assessment of breast volume, visceral adipose tissue (VAT), abdominal and lower‐body subcutaneous AT (SAT), and intermuscular AT (IMAT), a 2‐h oral glucose tolerance test (OGTT), and fasting phlebotomy for assessment of triglyceride, total, high‐density lipoprotein–, and low‐density lipoprotein–cholesterol levels. Breast volume was not associated with any of the cardiometabolic risk factors assessed (P > 0.05). However, VAT was consistently associated with a number of cardiometabolic risk factors (OGTT glucose, OGTT insulin, and triglyceride levels) after controlling for age, BMI, WC, breast volume, and the other AT depots. In univariate models, breast volume was positively associated with VAT, IMAT, and abdominal and lower‐body SAT (P < 0.05). After controlling for age, BMI, and WC level, breast volume remained positively associated with VAT and IMAT (P < 0.05), such that women with the highest breast volume had ∼1.1 and 1.3 kg more VAT and IMAT, respectively, but no more abdominal or lower‐body SAT, by comparison to women with the smallest breast volume. Thus, the previously documented association between breast size and type 2 diabetes risk may be in part explained by excess VAT and/or IMAT deposition.
Traditional Anthropometric Parameters Still Predict Metabolic Disorders in Women With Severe Obesity
Authors: Ledoux Séverine , Coupaye Muriel , Essig Marie , Msika Simon , Roy Carine , Queguiner Isabelle , Clerici Christine , Larger Etienne
Published: October 2009

It is well established that fat distribution rather than the total quantity of fat is the major determinant of cardiovascular risk in overweight subjects. However, it is not known whether the concept of fat distribution still makes sense in severely obese subjects. Particularly, the role of visceral fat accumulation and/or of adipocyte hypertrophy in insulin resistance (IR) has not been studied in this population. Therefore, the aim of this study was to clarify the determinants of metabolic disorders in severely obese women. We performed a cross‐sectional study in 237 severely obese women (BMI >35 kg/m2). We assessed total body fat mass and fat distribution by anthropometric measurements (BMI and waist‐to‐hip ratio (WHR)) and by dual‐energy X‐ray absorptiometry (DXA). In 22 women, we measured subcutaneous and visceral adipocyte size on surgical biopsies. Mean BMI was 44 ± 7 kg/m2 (range 35–77), mean age 37 ± 11 years (range 18–61). Lipid parameters (triglycerides, high‐density lipoprotein cholesterol) and IR markers (fasting insulin and homeostasis model assessment (HOMA) index) correlated with fat distribution, whereas inflammatory parameters (C‐reactive protein, fibrinogen) correlated only with total fat mass. An association was observed between android fat distribution and adipocyte hypertrophy. Visceral adipocyte hypertrophy was associated with both IR and hypertension, whereas subcutaneous fat‐cell size was linked only to hypertension. Our results obtained in a large cohort of women showed that fat distribution still predicts metabolic abnormalities in severe obesity. Furthermore, we found a cluster of associations among fat distribution, metabolic syndrome (MS), and adipocyte hypertrophy.
Genetic Epidemiology of BMI and Body Mass Change From Adolescence to Young Adulthood
Authors: North Kari E. , Graff Mariaelisa , Adair Linda S. , Lange Ethan M. , Lange Leslie A. , Guo Guang , Gordon‐Larsen Penny
Published: October 2009

The complex interplay between genes and environment affecting body mass gain over lifecycle periods of risk is not well understood. We use longitudinal sibling cohort data to examine the role of shared household environment, additive genetic, and shared genetic effects on BMI and BMI change. In the National Longitudinal Study of Adolescent Health, siblings and twin pairs sharing households for ≥10 years as adolescents (N = 5,524; mean = 16.5 ± 1.7 years) were followed into young adulthood (N = 4,368; mean = 22.4 ± 1.8 years). Using a variance component approach, we quantified genetic and household effects on BMI in siblings and nonsiblings sharing household environments over time. Adjusting for race, age, sex, and age‐by‐sex interaction, we detected a heritability of 0.43 ± 0.05 for BMI change. Significant household effects were noted during the young adulthood period only (0.11 ± 0.06). We find evidence for shared genetic effects between BMI and BMI change during adolescence (genetic correlation (ρG) = 0.61 ± 0.03) and young adulthood (ρG = 0.23 ± 0.06). Our findings support a complex etiology of BMI and BMI change.
Fasting Plasma Glucose (FPG) and the Risk of Impaired Glucose Tolerance in Obese Children and Adolescents
Authors: Maffeis Claudio , Pinelli Leonardo , Brambilla Paolo , Banzato Claudia , Valzolgher Laura , Ulmi Daniela , Di Candia Stefania , Cammarata Bruna , Morandi Anita
Published: October 2009

A timely diagnosis of impaired glucose tolerance (IGT) is desirable in obesity. The oral glucose tolerance test (OGTT), the gold standard to diagnose this condition, may not be realistically performed in all patients due to discomfort, labor, and cost. The aim of this study was to assess whether one or more biochemical indexes measured in fasting conditions could be used to identify obese children at risk of IGT. A cohort of 563 white obese children and adolescents (M/F: 315/248; aged 4–17 years) was recruited and underwent anthropometric evaluation and OGTT. Anthropometric parameters, fasting plasma glucose (FPG), fasting serum insulin (FSI), and homeostasis model assessment of insulin resistance (HOMAIR) were tested in pursuit of a possible threshold to be used as a predictor of IGT. Thirty‐seven children (6.9%) had IGT and one child (0.1%) had type 2 diabetes (T2D). FPG, FSI, and HOMAIR were all significantly higher in children with IGT than in children without IGT. Receiver‐operating characteristic (ROC) curve analyses run for gender and puberty‐adjusted FPG, FSI, and HOMAIR were all significant: area under the curve (95% confidence interval) equaled 0.68 (0.59–0.76), 0.66 (0.56–0.76), and 0.68 (0.59–0.78), respectively. The three parameters did not show significantly different sensitivity/specificity in the pooled population or in the gender/puberty subgroups. Thresholds varied among gender/puberty subgroups for FSI and HOMAIR, but not for FPG, which showed a fixed threshold of 86 mg/dl. A gender/puberty independent cutoff of FPG may be considered a screening tool to narrow clinical indication to OGTT in obese white children and adolescents.
The Imprinted Gene Neuronatin Is Regulated by Metabolic Status and Associated With Obesity
Authors: Vrang Niels , Meyre David , Froguel Phillippe , Jelsing Jacob , Tang‐Christensen Mads , Vatin Vincent , Mikkelsen Jens D. , Thirstrup Kenneth , Larsen Leif K. , Cullberg Karina B. , Fahrenkrug Jan , Jacobson Per , Sjöström Lars , Carlsson Lena M.S. , Liu Yongjun , Liu Xiaogang , Deng Hong‐Wen , Larsen Philip J.
Published: October 2009

Using restriction fragment differential display (RFDD) technology, we have identified the imprinted gene neuronatin (Nnat) as a hypothalamic target under the influence of leptin. Nnat mRNA expression is decreased in several key appetite regulatory hypothalamic nuclei in rodents with impaired leptin signaling and during fasting conditions. Furthermore, peripheral administration of leptin to ob/ob mice normalizes hypothalamic Nnat expression. Comparative immunohistochemical analysis of human and rat hypothalami demonstrates that NNAT protein is present in anatomically equivalent nuclei, suggesting human physiological relevance of the gene product(s). A putative role of Nnat in human energy homeostasis is further emphasized by a consistent association between single nucleotide polymorphisms (SNPs) in the human Nnat gene and severe childhood and adult obesity.
Identification of the key structural motifs involved in HspB8/HspB6–Bag3 interaction
Authors: Fuchs Margit , Poirier Dominic J. , Seguin Samuel J. , Lambert Herman , Carra Serena , Charette Steve J. , Landry Jacques
Published: October 2009

The molecular chaperone HspB8 [Hsp (heat-shock protein) B8] is member of the B-group of Hsps. These proteins bind to unfolded or misfolded proteins and protect them from aggregation. HspB8 has been reported to form a stable molecular complex with the chaperone cohort protein Bag3 (Bcl-2-associated athanogene 3). In the present study we identify the binding regions in HspB8 and Bag3 crucial for their interaction. We present evidence that HspB8 binds to Bag3 through the hydrophobic groove formed by its strands β4 and β8, a region previously known to be responsible for the formation and stability of higher-order oligomers of many sHsps (small Hsps). Moreover, we demonstrate that two conserved IPV (Ile-Pro-Val) motifs in Bag3 mediate its binding to HspB8 and that deletion of these motifs suppresses HspB8 chaperone activity towards mutant Htt43Q (huntingtin exon 1 fragment with 43 CAG repeats). In addition, we show that Bag3 can bind to the molecular chaperone HspB6. The interaction between HspB6 and Bag3 requires the same regions that are involved in the HspB8–Bag3 association and HspB6–Bag3 promotes clearance of aggregated Htt43Q. Our findings suggest that the co-chaperone Bag3 might prevent the accumulation of denatured proteins by regulating sHsp activity and by targeting their substrate proteins for degradation. Interestingly, a mutation in one of Bag3 IPV motifs has recently been associated with the development of severe dominant childhood muscular dystrophy, suggesting a possible important physiological role for HspB–Bag3 complexes in this disease.
Comparison of the cellular and biochemical properties of Plasmodium falciparum choline and ethanolamine kinases
Authors: Alberge Blandine , Gannoun-Zaki Leila , Bascunana Céline , Tran van Ba Christophe , Vial Henri , Cerdan Rachel
Published: October 2009

The proliferation of the malaria-causing parasite Plasmodium falciparum within the erythrocyte is concomitant with massive phosphatidylcholine and phosphatidylethanolamine biosynthesis. Based on pharmacological and genetic data, de novo biosynthesis pathways of both phospholipids appear to be essential for parasite survival. The present study characterizes PfCK (P. falciparum choline kinase) and PfEK (P. falciparum ethanolamine kinase), which catalyse the first enzymatic steps of these essential metabolic pathways. Recombinant PfCK and PfEK were expressed as His6-tagged fusion proteins from overexpressing Escherichia coli strains, then purified to homogeneity and characterized. Using murine polyclonal antibodies against recombinant kinases, PfCK and PfEK were shown to be localized within the parasite cytoplasm. Protein expression levels increased during erythrocytic development. PfCK and PfEK appeared to be specific to their respective substrates and followed Michaelis–Menten kinetics. The Km value of PfCK for choline was 135.3±15.5 μM. PfCK was also able to phosphorylate ethanolamine with a very low affinity. PfEK was found to be an ethanolamine-specific kinase (Km=475.7±80.2 μM for ethanolamine). The quaternary ammonium compound hemicholinium-3 and an ethanolamine analogue, 2-amino-1-butanol, selectively inhibited PfCK or PfEK. In contrast, the bis-thiazolium compound T3, which was designed as a choline analogue and is currently in clinical trials for antimalarial treatment, affected PfCK and PfEK activities similarly. Inhibition exerted by T3 was competitive for both PfCK and PfEK and correlated with the impairment of cellular phosphatidylcholine biosynthesis. Comparative analyses of sequences and structures for both kinase types gave insights into their specific inhibition profiles and into the dual capacity of T3 to inhibit both PfCK and PfEK.
The aqueous geochemistry of thallium: speciation and solubility of thallium in low temperature systems
Authors: Xiong Yongliang
Published: October 2009

Environmental context. The aqueous geochemistry of thallium is not well known in comparison with cadmium and lead, although it is more highly toxic, and at the same time has a wide range of industrial applications. A database allowing us to reliably predict the speciation and solubility of thallium in various environments in low temperature systems would be invaluable in providing some understanding of thallium’s mobilisation and mitigation. We propose here such a thermodynamic database based on critical reviews.
Abstract. Thallium is a highly toxic element, and at the same time it has a wide range of applications in industry. Therefore, it is important to know its speciation and solubility under low temperature conditions. This study expands the thermodynamic database of the first paper of this series on the aqueous geochemistry of thallium by providing the formation constants of some important thallium complexes, including TlEDTA3–, TlOx– (Ox: oxalate), TlSuc– (Suc: succinate), TlMal– (Mal: malonate) and TlHPO4–. This study also recommends the solubility product constant of TlCl(s) as 10–3.65. The combined database allows us to model reliably the speciation and solubility of thallium in the Earth surface environments. As an example, the speciation and solubility of thallium in soil solutions are presented based on thermodynamic calculations.
Low temperature headspace desorption of volatile organic compounds trapped in air sampling solid-supports
Authors: Esteve-Turrillas Francesc A. , Pastor Agustín , de la Guardia Miguel
Published: October 2009

Environmental context. The monitoring of volatile organic compounds (VOCs) in air is of great importance for air quality on both local and global scales. The determination of VOCs can be carried out by gas chromatography–mass spectrometry (GC-MS) after active or passive sampling and (high temperature) thermal desorption. An attractive alternative would be to combine GC-MS with headspace (HS) systems as it allows simpler, faster, low temperature desorption. We present here the first report of HS-GC-MS for the determination of VOCs in air sampled using solid supports.
Abstract. The use of a headspace (HS) for low temperature desorption of VOCs, previously sorbed from indoor air on solid supports, has been evaluated in order to improve the GC-MS determinations in environmental studies. Graphitised carbon black (GCB), Porapak and Tenax were considered in this study. The HS injector does not allow temperatures higher than 150°C, so there is no a complete desorption of VOCs. However highly volatile compounds were completely desorbed from Porapak and Tenax, but compounds of low volatility showed a strong retention with recoveries of 71–100% for Porapak and 59–100% for Tenax. All studied VOCs were quantitatively desorbed from GCB. Only 100 μL of the HS volume is injected in the chromatographic system. So in spite of the reduced sensitivity we are able to make replicate analyses on the same sampler. Additional experiments were performed using the proposed methodology for the analysis of aforementioned supports in passive and active sampling modes. In short, the proposed methodology reduces the energy consumed and makes it possible to determine the VOCs in air with reduced cost media. The developed methodology permits the determination of 32 VOCs with limits of detection values around 1 μg m–3 when actively sampling air at 50 mL min–1 for 2 h and using 100 mg solid sorbent.
Carp chemical sensing and the potential of natural environmental attractants for control of carp: a review
Authors: Elkins Aaron , Barrow Russell , Rochfort Simone
Published: October 2009

Environmental context. Carp are responsible for causing significant damage to lakes and rivers resulting in highly turbid water impacting native fish. At present there are no effective ways to manage the damage caused by carp or eradicate them, but the efficiency of carp removal from our waterways can be enhanced by the development of naturally occurring environmental attractants. As part of a broader pest management scheme the implementation of these attractants can significantly enhance the effectiveness of eradication programs and lead to the restoration of our waterways.
Abstract. Cyprinus carpio, a species of carp commonly known as European or common carp, are invasive alien species in Australian inland waters and have an extensive impact on biodiversity and the aquatic environment. The control and eradication of carp is a major focus of fisheries services throughout Australia, but at present there is no wholly successful way to limit the damage caused. An integrated pest management scheme (IPM) is the most likely approach to be effective. Such a scheme could employ current tactics such as trapping in combination with new strategies including attractants or deterrents. Among proposed attractants are environmentally derived chemicals. Carp have long been observed to prefer certain habitats and environmental conditions over others, although the reasons for such a preference are not well defined. This article reviews the current scientific literature for chemical reception and attraction in carp with an emphasis on environmentally derived attractants and the potential for use of these chemical cues to enhance IPM strategies with minimal environmental impact.
Multi-criteria ranking and source apportionment of fine particulate matter in Brisbane, Australia
Authors: Friend Adrian J. , Ayoko Godwin A.
Published: October 2009

Environmental context. There are serious global concerns about the environmental and health effects of atmospheric air pollutants. However, estimates of pollutants from measurements made in the proximity of a source do not always represent the ultimate atmospheric concentrations. Therefore alternative methods of attributing pollutants to sources, and estimating their contributions to atmospheric concentrations, as demonstrated in the current work, will become an increasingly important area of environmental research.
Abstract. This paper reports the application of multicriteria decision making techniques, Preference Ranking Organisation Methods for Enrichment Evaluation (PROMETHEE) and Graphical Analysis for Interactive Assistance (GAIA), and receptor models, principal component analysis/absolute principal component scores (PCA/APCS) and positive matrix factorisation (PMF), to data from an air monitoring site located on the campus of Queensland University of Technology in Brisbane, Australia and operated by Queensland Environmental Protection Agency (QEPA). The data consisted of the concentrations of 21 chemical species and meteorological data collected between 1995 and 2003. PROMETHEE/GAIA separated the samples into those collected when leaded and unleaded petrol were used to power vehicles in the region. The number and source profiles of the factors obtained from PCA/APCS and PMF analyses were compared. There are noticeable differences in the outcomes possibly because of the non-negative constraints imposed on the PMF analysis. Whereas PCA/APCS identified 6 sources, PMF reduced the data to 9 factors. Each factor had distinctive compositions that suggested that motor vehicle emissions, controlled burning of forests, secondary sulfate, sea salt and soil were the most important sources of fine particulate matter at the site. The most plausible locations of the sources were identified by combining the results obtained from the receptor models with meteorological data. The study demonstrated the potential benefits of combining results from multi-criteria decision making analysis with those from receptor models in order to gain insights into information that could enhance the development of air pollution control measures.
T-box 2, a mediator of Bmp-Smad signaling, induced hyaluronan synthase 2 and Tgfβ2 expression and endocardial cushion formation
Authors: Shirai Manabu , Imanaka-Yoshida Kyoko , Schneider Michael D. , Schwartz Robert J. , Morisaki Takayuki
Published: October 2009

During early heart development, Tbx2 gene expression is initiated in the cardiac crescent and then becomes restricted to the outflow tract and the atrioventricular region. We identified a
Tbx2
regulatory region, enriched in multiple Smad sites, sufficient to reproduce
Tbx2
expression patterns overlapping Bmp2 and Bmp4 gene activity in the heart. The role of
Tbx2
in cardiogenesis was analyzed by using Cre-LoxP activated
Tbx2
transgenic misexpression in chamber myocardium. Ventricular
Tbx2
misexpression exhibited an abnormally narrow chamber lumen owing to the expansion of
Hyaluronan synthase 2
expression in the ECM or cardiac jelly and the appearance of the endocardial cushions (ECs). Excessive
Tbx2
also induced
Tgf
β
2
, which coincided with the outgrowth epithelial-mesenchymal transformed cells in ventricular and atrial tissues modifying cardiomyocyte identity from chamber type to non-chamber type.
Tbx2
, a central intermediary of Bmp-Smad signaling, has a central part in directing
Has2
and
Tgf
β
2
expression, facilitating EC formation.
T-tubule disorganization and defective excitation-contraction coupling in muscle fibers lacking myotubularin lipid phosphatase
Authors: Al-Qusairi Lama , Weiss Norbert , Toussaint Anne , Berbey Céline , Messaddeq Nadia , Kretz Christine , Sanoudou Despina , Beggs Alan H. , Allard Bruno , Mandel Jean-Louis , Laporte Jocelyn , Jacquemond Vincent , Buj-Bello Anna
Published: October 2009

Skeletal muscle contraction is triggered by the excitation-contraction (E-C) coupling machinery residing at the triad, a membrane structure formed by the juxtaposition of T-tubules and sarcoplasmic reticulum (SR) cisternae. The formation and maintenance of this structure is key for muscle function but is not well characterized. We have investigated the mechanisms leading to X-linked myotubular myopathy (XLMTM), a severe congenital disorder due to loss of function mutations in the
MTM1
gene, encoding myotubularin, a phosphoinositide phosphatase thought to have a role in plasma membrane homeostasis and endocytosis. Using a mouse model of the disease, we report that
Mtm1
-deficient muscle fibers have a decreased number of triads and abnormal longitudinally oriented T-tubules. In addition, SR Ca
2+
release elicited by voltage-clamp depolarizations is strongly depressed in myotubularin-deficient muscle fibers, with myoplasmic Ca
2+
removal and SR Ca
2+
content essentially unaffected. At the molecular level,
Mtm1
-deficient myofibers exhibit a 3-fold reduction in type 1 ryanodine receptor (RyR1) protein level. These data reveal a critical role of myotubularin in the proper organization and function of the E-C coupling machinery and strongly suggest that defective RyR1-mediated SR Ca
2+
release is responsible for the failure of muscle function in myotubular myopathy.
Shape transition during nest digging in ants
Authors: Toffin Etienne , Di Paolo David , Campo Alexandre , Detrain Claire , Deneubourg Jean-Louis
Published: October 2009

Nest building in social insects is among the collective processes that show highly conservative features such as basic modules (chambers and galleries) or homeostatic properties. Although ant nests share common characteristics, they exhibit a high structural variability, of which morphogenesis and underlying mechanisms remain largely unknown. We conducted two-dimensional nest-digging experiments under homogeneous laboratory conditions to investigate the shape diversity that emerges only from digging dynamics and without the influence of any environmental heterogeneity. These experiments revealed that, during the excavation, a morphological transition occurs because the primary circular cavity evolves into a ramified structure through a branching process. Such a transition is observed, whatever the number of ants involved, but occurs more frequently for a larger number of workers. A stochastic model highlights the central role of density effects in shape transition. These results indicate that nest digging shares similar properties with various physical, chemical, and biological systems. Moreover, our model of morphogenesis provides an explanatory framework for shape transitions in decentralized growing structures in group-living animals.
Role of cortical tension in bleb growth
Authors: Tinevez Jean-Yves , Schulze Ulrike , Salbreux Guillaume , Roensch Julia , Joanny Jean-François , Paluch Ewa
Published: October 2009

Blebs are spherical membrane protrusions often observed during cell migration, cell spreading, cytokinesis, and apoptosis, both in cultured cells and in vivo. Bleb expansion is thought to be driven by the contractile actomyosin cortex, which generates hydrostatic pressure in the cytoplasm and can thus drive herniations of the plasma membrane. However, the role of cortical tension in bleb formation has not been directly tested, and despite the importance of blebbing, little is known about the mechanisms of bleb growth. In order to explore the link between cortical tension and bleb expansion, we induced bleb formation on cells with different tensions. Blebs were nucleated in a controlled manner by laser ablation of the cortex, mimicking endogenous bleb nucleation. Cortical tension was modified by treatments affecting the level of myosin activity or proteins regulating actin turnover. We show that there is a critical tension below which blebs cannot expand. Above this threshold, the maximal size of a bleb strongly depends on tension, and this dependence can be fitted with a model of the cortex as an active elastic material. Together, our observations and model allow us to relate bleb shape parameters to the underlying cellular mechanics and provide insights as to how bleb formation can be biochemically regulated during cell motility.
Rescue of CF airway epithelial cell function in vitro by a CFTR potentiator, VX-770
Authors: Van Goor Fredrick , Hadida Sabine , Grootenhuis Peter D. J. , Burton Bill , Cao Dong , Neuberger Tim , Turnbull Amanda , Singh Ashvani , Joubran John , Hazlewood Anna , Zhou Jinglan , McCartney Jason , Arumugam Vijayalaksmi , Decker Caroline , Yang Jennifer , Young Chris , Olson Eric R. , Wine Jeffery J. , Frizzell Raymond A. , Ashlock Melissa , Negulescu Paul
Published: October 2009

Cystic fibrosis (CF) is a fatal genetic disease caused by mutations in the gene encoding the CF transmembrane conductance regulator (CFTR), a protein kinase A (PKA)-activated epithelial anion channel involved in salt and fluid transport in multiple organs, including the lung. Most CF mutations either reduce the number of CFTR channels at the cell surface (e.g., synthesis or processing mutations) or impair channel function (e.g., gating or conductance mutations) or both. There are currently no approved therapies that target CFTR. Here we describe the in vitro pharmacology of VX-770, an orally bioavailable CFTR potentiator in clinical development for the treatment of CF. In recombinant cells VX-770 increased CFTR channel open probability (P
o
) in both the F508del processing mutation and the G551D gating mutation. VX-770 also increased Cl
−
secretion in cultured human CF bronchial epithelia (HBE) carrying the G551D gating mutation on one allele and the F508del processing mutation on the other allele by ≈10-fold, to ≈50% of that observed in HBE isolated from individuals without CF. Furthermore, VX-770 reduced excessive Na
+
and fluid absorption to prevent dehydration of the apical surface and increased cilia beating in these epithelial cultures. These results support the hypothesis that pharmacological agents that restore or increase CFTR function can rescue epithelial cell function in human CF airway.
A hydroxycinnamoyltransferase responsible for synthesizing suberin aromatics in
Arabidopsis
Authors: Gou Jin-Ying , Yu Xiao-Hong , Liu Chang-Jun
Published: October 2009

Suberin, a polyester polymer in the cell wall of terrestrial plants, controls the transport of water and nutrients and protects plant from pathogenic infections and environmental stresses. Structurally, suberin consists of aliphatic and aromatic domains;
p
-hydroxycinnamates, such as ferulate,
p
-coumarate, and/or sinapate, are the major phenolic constituents of the latter. By analyzing the “wall-bound” phenolics of mutant lines of
Arabidopsis
deficient in a family of acyl-CoA dependent acyltransferase (BAHD) genes, we discovered that the formation of aromatic suberin in
Arabidopsis
, primarily in seed and root tissues, depends on a member of the BAHD superfamily of enzymes encoded by
At5g41040
. This enzyme exhibits an ω-hydroxyacid hydroxycinnamoyltransferase activity with an in vitro kinetic preference for feruloyl-CoA and 16-hydroxypalmitic acid. Knocking down or knocking out the
At5g41040
gene in
Arabidopsis
reduces specifically the quantity of ferulate in suberin, but does not affect the accumulation of
p
-coumarate or sinapate. The loss of the suberin phenolic differentially affects the aliphatic monomer loads and alters the permeability and sensitivity of seeds and roots to salt stress. This highlights the importance of suberin aromatics in the polymer's function.