Genome-wide analysis in response to nitrogen and carbon identifies regulators for root AtNRT2 transporters.

In Arabidopsis (Arabidopsis thaliana), the High-Affinity Transport System (HATS) for root nitrate (NO3-) uptake depends mainly on four NRT2 NO3- transporters, namely NRT2.1, NRT2.2, NRT2.4, and NRT2.5. The HATS is the target of many regulations to coordinate nitrogen (N) acquisition with the N status of the plant and with carbon (C) assimilation through photosynthesis. At the molecular level, C and N signaling pathways control gene expression of the NRT2 transporters. Although several regulators of these transporters have been identified in response to either N or C signals, the response of NRT2 gene expression to the interaction of these signals has never been specifically investigated, and the underlying molecular mechanisms remain largely unknown. To address this question we used an original systems biology approach to model a regulatory gene network targeting NRT2.1, NRT2.2, NRT2.4, and NRT2.5 in response to N/C signals. Our systems analysis of the data identified three transcription factors, TGA3, MYC1, and bHLH093. Functional analysis of mutants combined with yeast one-hybrid experiments confirmed that all three transcription factors are regulators of NRT2.4 or NRT2.5 in response to N or C signals. These results reveal a role for TGA3, MYC1, and bHLH093 in controlling the expression of root NRT2 transporter genes.

[Parasitosis and irritable bowel syndrome]. / Parasitosis y síndrome de intestino irritable.

Irritable bowel syndrome (IBS) is a functional disorder of the gastrointestinal tract characterised by multi-factorial aetiology. In IBS physiopathology are involved diverse factors between them biological, psychosocial, and environmental components which affect the immune activation status of gut mucosa. Among these factors is recognized the intestinal parasitosis. Post-infection IBS (PI-IBS) is recognised as a subgroup of functional disorders whose symptoms onset appear after a symptomatic intestinal infection caused by microbial agents. There are few studies regarding of relationship between IBS and intestinal parasitosis in Chile. However, is has been well described a positive association between IBS and Blastocystis hominis infections, one of prevalent parasites in Chile. In other countries, is also described a relationship between IBS and amebiasis and giardiasis. Both, characterized by a common mode of transmission through water as well as contaminated food. Because the high prevalence of parasitosis in our country it is necessary to expand the association studies to clarify the strength of the parasites ethiology in IBS.

Naturalistic Enactment to Elicit and Recognize Caregiver State Anxiety.

Caring for people with dementia imposes significant stress on family members and caregivers. Often, these informal caregivers have no coping strategy to deal with these behaviors. Anxiety and stress episodes are often triggered by problematic behaviors exhibited by the person who suffers from dementia. Detecting these behaviors could help them in dealing with them and reduce caregiver burden. However, work on anxiety detection using physiological signals has mostly been done under controlled conditions. In this paper we describe an experiment aimed at inducing anxiety among caregivers of people with dementia under naturalistic conditions. We report an experiment, using the naturalistic enactment technique, in which 10 subjects were asked to care for an older adult who acts as if she experiences dementia. We record physiological signals from the participants (GSR, HR, EEG) during the sessions that lasted for approximately 30 min. We explain how we obtained ground truth from self-report and observation data. We conducted two different tests using the Support Vector Machine technique. We obtained an average precision of 77.8 % and 38.1 % recall when classifying two different possible states: "Anxious" and "Not anxious". Analysis of the data provides evidence that the experiment elicits state anxiety and that it can be detected using wearable sensors. Furthermore, if episodes of problematic behaviors can also be detected, the recognition of anxiety in the caregiver can be improved, leading to the enactment of appropriate interventions to help caregivers cope with anxiety episodes.

Parasitosis y síndrome de intestino irritable / Parasitosis and irritable bowel syndrome

El síndrome de intestino irritable (SII) es un trastorno funcional digestivo de etiología multifactorial. En su fisiopatología se describen diversos factores, tanto biológicos, como psicológicos y ambientales, que afectan el estado de activación de células inmunes en la mucosa intestinal. Entre los factores ambientales se incluye la presencia de alguna parasitosis intestinal. El síndrome de intestino irritable post-infeccioso (SII-PI) es reconocido como un subgrupo de estos trastornos, cuya aparición de los síntomas es posterior a una infección intestinal provocada por agentes microbianos. A pesar de que en Chile hay pocos estudios respecto a la relación entre SII y parasitosis intestinal, se ha descrito la existencia de una asociación positiva entre SII e infecciones por Blastocistis hominis, uno de los parásitos prevalentes en Chile. En otros países, se ha descrito además una relación entre SII, amebiasis y giardiasis. Por la alta prevalencia de parasitosis en nuestro país, existe la necesidad de ampliar los estudios para clarificar la fuerza de la asociación entre parasitosis y SII.

Irritable bowel syndrome (IBS) is a functional disorder of the gastrointestinal tract characterised by multi-factorial aetiology. In IBS physiopathology are involved diverse factors between them biological, psychosocial, and environmental components which affect the immune activation status of gut mucosa. Among these factors is recognized the intestinal parasitosis. Post-infection IBS (PI-IBS) is recognised as a subgroup of functional disorders whose symptoms onset appear after a symptomatic intestinal infection caused by microbial agents. There are few studies regarding of relationship between IBS and intestinal parasitosis in Chile. However, is has been well described a positive association between IBS and Blastocystis hominis infections, one of prevalent parasites in Chile. In other countries, is also described a relationship between IBS and amebiasis and giardiasis. Both, characterized by a common mode of transmission through water as well as contaminated food. Because the high prevalence of parasitosis in our country it is necessary to expand the association studies to clarify the strength of the parasites ethiology in IBS.

Determinación de la calidad microbiológica y sanitaria de alimentos preparados vendidos en la vía pública de la ciudad de Bogotá / Determination of microbiological and sanitary quality of prepared food sold in the street of the city of Bogota

Objetivo. Evaluar la calidad microbiológica de algunos alimentos preparados y servidos en puestos ambulantes cercanos a universidades en Bogotá D.C. Materiales y métodos. Se realizaron recuentos de mesófilos aerobios, mohos y levaduras, Staphylococcus aureus, Bacillus cereus, esporas de Clostridium sulfito reductor, determinación de coliformes totales y fecales e investigación de Salmonella spp y Listeria monocytogenes. Resultados. Los hallazgos obtenidos en este estudio en Bogotá D.C califican a la mayoría de puestos de venta ambulatoria de alimentos con riesgo sanitario alto. Se requiere un mayor control por parte de las autoridades correspondientes y una mayor información y capacitación a vendedores y consumidores de este tipo de alimentos.

Objective. Determinate the microbiological quality of some prepared foods and served at stalls near universities in Bogota DC. Materials and methods. Mesophilic aerobic counts, molds and yeasts, Staphylococcus aureus, Bacillus cereus, sulfite reducing Clostridium spores, determination of total and fecal coliforms and investigation of Salmonella and Listeria monocytogenes were made. Results. The findings of this study in Bogota DC qualify most street vending stalls of foods high health risk. Need more control by the appropriate authorities and better information and training to sellers and consumers of these foods.

Identifying transfer mechanisms and sources of decabromodiphenyl ether (BDE 209) in indoor environments using environmental forensic microscopy.

Although the presence of polybrominated diphenyl ethers (PBDEs) in house dust has been linked to consumer products, the mechanism of transfer remains poorly understood. We conjecture that volatilized PBDEs will be associated with dust particles containing organic matter and will be homogeneously distributed in house dust. In contrast, PBDEs arising from weathering or abrasion of polymers should remain bound to particles of the original polymer matrix and will be heterogeneously distributed within the dust. We used scanning electron microscopy and othertools of environmental forensic microscopy to investigate PBDEs in dust, examining U.S. and U.K. dust samples with extremely high levels of BDE 209 (260-2600 microg/g), a nonvolatile compound at room temperature. We found that the bromine in these samples was concentrated in widely scattered, highly contaminated particles. In the house dust samples from Boston (U.S.), bromine was associated with a polymer/organic matrix. These results suggest that the BDE 209 was transferred to dust via physical processes such as abrasion or weathering. In conjunction with more traditional tools of environmental chemistry, such as gas chromatography/mass spectrometry (GC/MS), environmental forensic microscopy provides novel insights into the origins of BDE 209 in dust and their mechanisms of transfer from products.

Multimedia modeling of polybrominated diphenyl ether emissions and fate indoors.

We adapted an indoor multimedia fugacity model to consider emissions and fate of polybrominated diphenyl ethers (PBDEs) and to understand the variability of indoor concentrations. The model was applied to an office in which an 80% decrease in PBDE air concentration was observed after an old computer was exchanged with a newer one. PBDE-impregnated polyurethane foam (PUF) and carpet were treated as pseudo-steady-state components with specified fugacities derived from measured concentrations of 173 and 2140 ng x g(-1), respectively. Emission rates of 35 and 5.4 ng x h(-1), for the old and new computers, respectively, were calculated using the pseudo-steady-state approach. Particle movement (deposition and resuspension) dominates within-room transport processes, and dust removal (vacuuming) and air advection (ventilation) are the main loss processes. The most sensitive parameters to air concentrations and estimated emission rates are room temperature, particle concentrations and deposition velocity, and air exchange rates. The air exchange rates and bouncing on PUF furniture can alter whether the PUF and carpet are sources or sinks of PBDEs. Model results suggest that exposure via air can be reduced by removing dust, having a high air exchange rate, and low indoor temperatures.

Polychlorinated biphenyls in domestic dust from Canada, New Zealand, United Kingdom and United States: implications for human exposure.

Ingestion of indoor dust has been highlighted as an important pathway of exposure to brominated flame retardants. Hence, polychlorinated biphenyls (PCBs) were determined in indoor dust from homes in Amarillo/Austin, TX, USA (n=20; median concentration=200 ng Sigma PCB g(-1)); Birmingham, UK (n=20; 48 ng Sigma PCB g(-1)); Toronto, Canada (n=10; 260 ng Sigma PCB g(-1)); and Wellington, New Zealand (n=20; 46 ng Sigma PCB g(-1)). Concentrations in Canadian and US samples were statistically indistinguishable, but exceeded significantly (p<0.05) those in both New Zealand and UK dust. Principal component analysis revealed that while UK samples were enriched comparatively in lower molecular weight congeners; samples from other countries contained proportionally more mid-to-high molecular weight congeners. Concentrations of PCBs determined in air from the same 10 Canadian homes showed concentrations (median=4.9 ng Sigma PCB m(-3)) higher than those reported previously for UK homes (1.8 ng Sigma PCB m(-3)). Interpretation of these data alongside that for dietary exposure from other studies suggest that indoor exposures (i.e. air and dust combined) may be a significant contributor to overall exposure for the majority of the population - ranging from 4.3% to 87% in adults and 1.6-73% in toddlers. While inhalation is the principal indoor pathway under a typical dust ingestion scenario, exposure via dust ingestion exceeds that from either inhalation or diet for a small proportion of North American toddlers.

Concentrations of brominated flame retardants in dust from United Kingdom cars, homes, and offices: causes of variability and implications for human exposure.

Average concentrations of polybrominated diphenyl ethers (PBDEs) in dust in 30 homes, 18 offices, and 20 cars were 260,000, 31,000, and 340,000 ng SigmaPBDEs g(-1) respectively. Concentrations of BDEs 47, 99, 100, and 154 in cars exceeded significantly (p<0.05) those in homes and offices. Average concentrations of 1,2-bis(2,4,6-tribromophenoxy)ethane (TBE) and decabromodiphenyl ethane (DBDPE) in homes, offices, and cars respectively were lower at 120, 7.2, and 7.7 ng g(-1) (TBE) and 270, 170, and 400 ng g(-1) (DBDPE). BDE-209 concentrations in three samples are the highest to date at 2,600,000 (car), 2,200,000 (home), and 1,400,000 ng g(-1) (home). UK toddlers daily consuming 200 mg dust contaminated at the 95th percentile concentration, ingest 180 ng (Sigma)tri-hexa-BDEs and 310 microg BDE-209 day(-1). For TBE, exposure was lower than for PBDEs and hexabromocyclododecanes (HBCDs), while that for DBDPE was similar in magnitude to (Sigma)tri-hexa-BDEs, but less than for BDE-209 and HBCDs. BDE-209 concentrations recorded in ten samples taken at monthly intervals in one room varied 400-fold, implying caution when using single measurements of dust contamination for exposure assessment. Significant negative correlation was observed in one room between concentrations of BDE-47, 99, and 153 and dust loading (g dust m(-2) floor), suggesting "dilution" occurs at higher dust loadings.

Comparative evaluation of liquid chromatography-mass spectrometry versus gas chromatography-mass spectrometry for the determination of hexabromocyclododecanes and their degradation products in indoor dust.

Domestic and office dust samples (n=37) were analyzed for hexabromocyclododecanes (HBCDs) using gas chromatography-electron-capture negative ionization-mass spectrometry (GC-ECNI/MS) and liquid chromatography-electrospray tandem mass spectrometry (LC-ESI/MS/MS). To determine the best method to quantify HBCDs using GC-ECNI/MS, BDE 128 was used as internal standard (I.S.) in all samples, while 13C-labeled alpha-HBCD was used as I.S. in some samples. Total HBCD concentrations (sum of alpha-, beta-, and gamma-HBCD diastereomers) were calculated using response factors (RFs) for alpha- and gamma-HBCD as individual diastereomers and using an average RF for both diastereomers. Statistical comparison showed that concentrations obtained via GC-ECNI/MS were statistically indistinguishable (p>0.05) from those obtained using LC-ESI/MS/MS. The closest match between the two techniques was obtained using [13C]alpha-HBCD as I.S. and the average RF for alpha- and gamma-HBCDs. Excellent linear correlations (Pearson coefficient values r>0.9) were obtained between the GC-ECNI/MS and LC-ESI/MS/MS results, with slopes ranging from 0.76 to 1.36. Pentabromocyclododecenes (four isomers) and tetrabromocyclododecadienes (two isomers) were detected in the studied samples and were identified as degradation products of HBCDs after separation from the parent compound on the basis of both retention time and mass spectrum. This finding suggests that the elimination of HBr is the major degradation pathway for HBCDs in dust.

Hexabromocyclododecanes in indoor dust from Canada, the United Kingdom, and the United States.

alpha-, beta-, and gamma-hexabromocyclododecane diastereomers (HBCDs) were measured in house dust from Birmingham, U.K. (n=31, median concentration=730 ng sigmaHBCDs g(-1)); Amarillo/Austin, TX (n=13, 390 ng g(-1)); and Toronto, Canada (n=8, 640 ng g(-1)). Concentrations in dust (n=6, 650 ng g(-1)) from U.K. offices were within the range for UK homes. Concentrations from each country were statistically indistinguishable. In one UK house dust sample, 110,000 ng g(-1) was recorded-the highest recorded in indoor dust to date. While upper bound average U.K. dietary exposures for adults and toddlers, respectively, are 413 and 240 ng sigmaHBCDs day(-1), U.K. adults and toddlers daily ingesting, respectively, 50 and 200 mg of dust contaminated at the 95th percentile concentration are exposed, respectively, to 1100 and 4400 ng sigmaHBCDs day(-1). Normalized to body weight, this high-end exposure scenario estimate for toddlers is within the range reported elsewhere for occupationally exposed adults. While in commercial formulations gamma-HBCD predominates (>80%), alpha-HBCD in dust constitutes 14-67% of sigmaHBCDs (average 32%). Hence the predominance of the alpha-diastereomer in humans may arise partly from dust ingestion, and not solely to in vivo metabolism (when alpha-HBCD is formed from bioisomerization of other diastereomers), or dietary exposure (where alpha-HBCD predominates in most foodstuffs).

Polybrominated diphenyl ethers in domestic indoor dust from Canada, New Zealand, United Kingdom and United States.

Because of the similarities in European and North American dietary exposure, it has been suggested that the order of magnitude higher body burdens in North Americans may be due to international variations in exposure via ingestion of indoor dust. Furthermore, ingestion of indoor dust has been suggested as a possible source of PBDEs in the blood serum of New Zealanders. Hence, polybrominated diphenyl ethers (PBDEs) were measured in domestic indoor dust from: Amarillo/Austin, Texas, US; Birmingham, UK; Toronto, Canada; and Wellington, New Zealand. Concentrations of BDE 209 in two UK samples were - at 520,000 and 100,000 ng g(-1) - the highest ever recorded in a domestic (or office) indoor dust sample. Median concentrations in ng g(-1) were: in Canada 620 and 560 for Sigmatri-hexa-BDEs and BDE 209 respectively; in New Zealand 96, BDE 209 not determined; in the UK 59 and 2,800; and in the US 1600 and 1300. With respect to BDE 209, concentrations were in the order: UK approximately US>Canada. For Sigmatri-hexa-BDEs, the order of concentrations was US approximately Canada>>New Zealand approximately UK. Combined with principal component analysis of congener patterns, this suggests that, while North American dusts are contaminated by both Deca- and Penta-BDE commercial formulations, UK dusts are contaminated predominantly by Deca-BDE. The Octa-BDE formulation appears of minimal importance in accordance with available market demand figures. Despite the commercial formulations of PBDEs never having been manufactured in, nor imported into New Zealand, their presence in dusts from that country suggests international trade in PBDE-containing goods is an important pathway effecting their global distribution.

Concentrations of polychlorinated biphenyls in indoor air and polybrominated diphenyl ethers in indoor air and dust in Birmingham, United Kingdom: implications for human exposure.

Polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) were measured in air (using PUF disk passive samplers) in 31 homes, 33 offices, 25 cars, and 3 public microenvironments. Average concentrations of sigmaBDE (273 pg m(-3)) and sigmaPCB (8920 pg m(-3)) were an order of magnitude higher than those previously reported for outdoor air. Cars were the most contaminated microenvironment for sigmaBDE (average = 709 pg m(-3)), but the least for sigmaPCB (average = 1391 pg m(-3)). Comparison with data from a previous spatially consistent study, revealed no significant decline in concentrations of sigmaPCB in indoor air since 1997-98. Concentrations in indoor dust from 8 homes were on average 215.2 ng sigmaBDE g(-1), slightly higher than other European dust samples, but twenty times lower than Canadian samples. Inhalation makes an important contribution (between 4.2 and 63% for adults) to overall UK exposure to sigmaPCB. For sigmaBDE, dust ingestion makes a significant but--in contrast to Canada-a not overwhelming contribution (up to 37% for adults, and 69% for toddlers). Comparison of UK and Canadian estimates of absolute exposure to sigmaBDE suggest that differences in dust contamination are the likely cause of higher PBDE body burdens in North Americans compared to Europeans.

Facile formation of molybdenum(VI) monooxo aryloxides MoO(OAr)4-nCln from molybdenum dioxo dichloride.

Molybdenum monooxo compoundsMoO(OAr)4-nCln (n=0-2, Ar=2,6-Me2C6H3 or 2,6-i-Pr2C6H3) have been synthesized starting from the dioxo precursor MoO2Cl2. The complexes are characterized spectroscopically and by X-ray diffraction. The formation mechanism likely involves phenol precoordination followed by addition across the Mo=O bond.

Steric control of coordination number: A series of Mo(VI) dioxo diaryloxide complexes bearing 4-, 5-, and 6-coordinate environments.

The design, synthesis, and structure determination of a series of Mo(VI) dioxo diaryloxide complexes have been reported. By varying the steric bulk of the aryloxide ligand, control of the coordination number around the Mo(VI) center was achieved. All the complexes are characterized by analytical and spectroscopic techniques. Preliminary reactivity tests indicate that the 4-coordinate compound is the most stable and the 6-coordinate compound is the least stable.