Aerosol particle size distributions at a traffic exposed site and an urban background location in Oporto, Portugal

Aerosol size distributions from 6 to 700 nm were measured simultaneously at an urban background site and a roadside station in Oporto. The particle number concentration was higher at the traffic exposed site, where up to 90% of the size spectrum was dominated by the nucleation mode. Larger aerosol mode diameters were observed in the urban background site possibly due to the coagulation processes or uptake of gases during transport. Factor analysis has shown that road traffic and the neighbour stationary sources localised upwind affect the urban area thought intra-regional pollutant transport.

Nitrous oxide emissions from an intermittent aeration activated sludge system of an urban wastewater treatment plant

This study investigated the emission of N2O during the sequential aerated (60-min) and non-aerated (30-min) stages of an intermittent aeration cycle in an activated sludge wastewater treatment plant (WWTP). N2O emission occurred during both stages; however, emission was much higher during aeration. Air stripping is the major factor controlling transfer of N2O from the sewage to the atmosphere. The N2O emissions exclusively from the aeration tank represented 0.10% of the influent total nitrogen load and the per capita emission factor was almost 3 times higher than that suggested by the IPCC for inventories of N2O emission from WWTPs.

Inhalable particulate matter characterization in a medium-sized urban region in Brazil (São José dos Campos Town) - Part I: Morphology

In this study, the concentration and morphological characteristics of inhalable particulate material (PM10) were evaluated and associated with climatic conditions. The mean annual concentration was 11.0 µg m−3, varying between 0,647 µg m−3 and 36.8 µg m−3. Wind speed has a higher influence on PM10 dispersion, but direction was associated with particle source. During the wet period, wind speed is the main dispersion factor, while speed and direction both are important during the dry period. Based on the morphological characteristics, it is concluded that biogenic particles prevail during the rainy season and terrigenous particles during the dry period, depending on the wind direction and intensity.

Evaluation of the dioxin and furan formation thermodynamics in combustion processes of urban solid wastes

Specific combustion programs (Gaseq, Chemical equilibria in perfect gases, Chris Morley) are used to model dioxin and formation in the incineration processes of urban solid wastes. Thanks to these programs, it is possible to establish correlations with the formation mechanisms postulated in literature on the subject. It was found that minimum oxygen quantities are required to obtain a significant formation of these compounds and that more furans than dioxins are formed. Likewise, dioxin and furan formation is related to the presence of carbon monoxide, and dioxin and furan distribution among its different compounds depends on the chlorine and hydrogen relative composition. This is due to the fact that an increased chlorine availability leads to the formation of compounds bearing a higher chlorine concentration (penta-, hexa-, hepta-, and octachlorides), whereas an increased hydrogen availability leads to the formation of compounds bearing a lower chlorine number (mono, di-, tri-, and tetrachlorides).

Assessment of hydrochemical quality of ground water under some urban areas within sana'a secreteriat

Groundwater from nine wells of three different districts, located at Sana'a secretariat was analyzed for hydrochemical quality assessment. Measurements of water quality parameters including pH, EC, CO3(2-), HCO3-, Cl-, NO3-, SO4(2-), Ca2+, Mg2+, Fe3+, K+, and Na+ were carried out . Classification of the groundwater samples according to Cl, SO4(2-), CO3(2-) and HCO3-, hardness (H), total dissolved solids (TDS), base-exchange, and meteoric genesis was demonstrated. Suitability of ground water samples for irrigation and industrial uses according to sodium adsorption ration (SAR), ratio of dissolved sodium (RDS), residual sodium carbonate (RSC) and saturation index (SI) was also investigated. The results of this study showed that almost all ground water samples were of good quality that makes them suitable for drinking and domestic uses. Results also indicated that even though some of the ground water samples were suitable for irrigation purposes, almost all of them were found not be good for industrial uses. Despite all drawbacks of the sewerage system built around Sana'a secretariat at the beginning of the first decade of the third millennium, the results of this study indicate that there is scope of significant improvement in Sana'a secretariat ground water quality.

Metabolism and gene polymorphisms of the folate pathway in Brazilian women with history of recurrent abortion

PURPOSE: To investigate the association between polymorphisms in genes that encode enzymes involved in folate- and vitamin B12-dependent homocysteine metabolism and recurrent spontaneous abortion (RSA).METHODS: We investigated the C677T and A1298C polymorphisms of the methylenetetrahydrofalate reductase gene (MTHFR), the A2756G polymorphism of the methionine synthase gene (MS) and the 844ins68 insertion of the cystathionine beta synthetase gene (CBS). The PCR technique followed by RFLP was used to assess the polymorphisms; the serum levels of homocysteine, vitamin B12 and folate were investigated by chemiluminescence. The EPI Info Software version 6.04 was used for statistical analysis. Parametric variables were compared by Student's t-test and nonparametric variables by the Wilcoxon rank sum test.RESULTS: The frequencies of gene polymorphisms in 89 women with a history of idiopathic recurrent miscarriage and 150 controls were 19.1 and 19.6% for the C677T, insertion, 20.8 and 26% for the A1298C insertion, 14.2 and 21.9% for the A2756G insertion, and 16.4 and 18% for the 844ins68 insertion, respectively. There were no significant differences between case and control groups in any of the gene polymorphisms investigated. However, the frequency of the 844ins68 insertion in the CBS gene was higher among women with a history of loss during the third trimester of pregnancy (p=0.003). Serum homocysteine, vitamin B12 and folate levels id not differ between the polymorphisms studied in the case and control groups. However, linear regression analysis showed a dependence of serum folate levels on the maintenance of tHcy levels.CONCLUSION: The investigated gene polymorphisms and serum homocysteine, vitamin B12 and folate levels were not associated with idiopathic recurrent miscarriage in the present study. Further investigations are needed in order to confirm the role of the CBS 844ins68 insertion in recurrent miscarriage.

Parenteral administration of vitamins A, D and E on the oxidative metabolism and function of polymorphonuclear leukocytes in swine

The weaning period of piglets is characterized by physiological alterations, such as decreased weight gain, increased reactive oxygen species (ROS) and increased serum cortisol levels with possible effects on the immune response. The effect of parenteral administration of vitamins A, D and E on production performance, oxidative metabolism, and the function of polymorphonuclear leukocytes (PMNLs) was assessed in piglets during the weaning period. The sample was comprised of 20 male piglets that were given an injectable ADE vitamin combination (135,000 IU vitamin A, 40,000 IU vitamin D and 40mg vitamin E/ animal) at 20 and 40 days of age. Weight gain, concentration of reduced glutathione (GSH), malondialdehyde (MDA), superoxide dismutase (SOD) and the microbicidal and phagocytic activity of PMNLs were assessed. No difference was observed in the average piglet weight during the study; however, a greater percentage of weight gain was observed after weaning in the treated group. The concentrations of GSH and SOD did not differ between groups, although lipid peroxidation was greater in the control group at 60 days of age. The investigated variables of oxidative metabolism were correlated as follows: -0.41 for GSH and MDA, -0.54 for GSH and SOD and 0.34 for MDA and SOD. The intensity of intracellular ROS production, the percentage of ROS-producing PMNLs and the intensity of phagocytosis by PMNLs did not differ between treatment groups. Administration of the injectable ADE combination improved the percentage of weight gain between 20 and 40 days of age, decreased oxidative stress at 60 days of age and did not influence the function of PMNLs in piglets.

Effect of exposure to sublethal concentrations of sodium cyanide on the carbohydrate metabolism of the Indian Major Carp Labeo rohita (Hamilton, 1822)

Experiments were designed to study in-vivo effects of sodium cyanide on biochemical endpoints in the freshwater fish Labeo rohita. Fish were exposed to two sublethal concentrations (0.106 and 0.064mg/L) for a period of 15 days. Levels of glycogen, pyruvate, lactate and the enzymatic activities of lactate dehydrogenase (LDH), succinate dehydrogenase (SDH), glucose-6-phosphate dehydrogenase (G6PDH), phosphorylase, alkaline phosphatase (ALP), acid phosphatase (AcP) were assessed in different tissues (liver, muscle and gills). Result indicated a steady decrease in glycogen, pyruvate, SDH, ALP and AcP activity with a concomitant increase in the lactate, phosphorylase, LDH and G6PD activity in all selected tissues. The alterations in all the above biochemical parameters were significantly (p<0.05) time and dose dependent. In all the above parameters, liver pointing out the intensity of cyanide intoxication compare to muscle and gills. Study revealed change in the metabolic energy by means of altered metabolic profile of the fish. Further, these observations indicated that even sublethal concentrations of sodium cyanide might not be fully devoid of deleterious influence on metabolism in L. rohita.

Oxidative metabolism and muscle biochemical profile of polo horses supplemented with an ADE vitamin complex

Horses used for the game of polo experience abrupt and frequent changes in exercise intensity. To meet this variable energy demand, the horses use both aerobic and anaerobic pathways in varying proportions and intensities. In this context, there must be a balance between the formation of reactive oxygen species (ROS) and the action of antioxidants to prevent oxidative stress and its consequences. The effect of supplementation with an ADE vitamin complex on oxidative metabolism was evaluated in 18 crossbred horses randomly divided between a treated group (TG) and a control group (CG). The TG animals received the ADE vitamin complex (1mL/50 kg of body weight) by deep intramuscular injection at 30 and 15 days before the game. The CG horses received 10ml of saline by the same administration route and schedule. During the polo match, the animals played for a total of 7.5 min. Blood samples were collected on the same days as the treatments were administered, and immediately before and at 15, 90 and 180 minutes after the game. The concentrations of creatine phosphokinase (CK), lactate dehydrogenase (LDH), lactate, glucose, aspartate aminotransferase (AST), glutathione (GSH), superoxide dismutase (SOD) and malondialdehyde (MDA) were measured in the blood samples. After the game, the TG demonstrated higher levels of AST, lactate and glucose than the CG, suggesting more efficient energy use by the treated animals. The higher GSH and lower lactate levels in the TG before the game suggest the presence of a greater antioxidant supply in the treated animals. The maintenance of the MDA levels indicates that neither of the groups exhibited oxidative stress.

Comparative uptake and metabolism of 2-[14C]-2,4-dichlorophenoxyacetic acid in callus cultures of monocot (Dioscorea spp.) and dicot (Nicotiana tabacum L.) plants

(Comparative uptake and metabolism of 2-[14C]-2,4-dichlorophenoxyacetic acid in callus cultures of monocot (Dioscorea spp.) and dicot (Nicotiana tabacum L.) plants). The uptake and metabolism of 2-[14C]-2,4-dichlorophenoxyacetic acid (2,4-D) were investigated in leaf calluses of Nicotiana tabacum, tuber calluses of Dioscorea opposita and calluses derived from zygotic embryos, leaves and petioles of Dioscorea composita. Striking similarities were evident in the patterns of 2,4-D metabolites and their chemical characteristics in the three callus types of D. composita compared, but significant differences were detected among the patterns of rnetabolites in the three species studied. Preliminary investigations on the stability of various metabolites (separated using TLC) by hydrolysis showed that sugar esters appeared to be the major metabolites in tobacco whilst in yams (D. opposita) glycosides were shown to be the main ones, which indicated a similarity between plants of Gramineae and Dioscoreaceae in terms of 2,4-D metabolism. Release of 2,4-D from tobacco callus cells upon their transfer to 2,4-D-free medium was detected and the implications of this are discussed in relation to the cultural conditions necessary to induce morphogenesis in vitro.

Ecophysiology and respiratory metabolism during the germination of Inga sessilis (Vell.) Mart. (Mimosaceae) seeds subjected to hypoxia and anoxia

This paper presents a study on the respiratory metabolism of germinating seeds of Inga sessilis subjected to normoxia, hypoxia and anoxia. Although it is typical of environments where waterlogging seldom occurs, 40% of its seeds are able to germinate under hypoxia; yet, anoxia periods over 96 h are lethal to the seeds. Ethanol is the main product of the seeds anaerobic metabolism, but the steep increase in lactate after 24 h anoxia or 48 h hypoxia may explain the drop in seed viability.

Intracellular and intercellular compartmentation of carbohydrate metabolism in leaves of temperate gramineae

This review considers the importance of compartmentation in the regulation of carbohydrate metabolism in leaves. We draw particular attention to the role of the vacuole as a site for storage of soluble sugars based on sucrose, and discuss briefly their characteristic metabolism. We also point out inconsistencies between the observed properties of vacuoles and the behaviour in vitro of the enzymes of fructan biosynthesis that do not support the hypothesis that the vacuole is the site of synthesis as well as of storage. We also consider compartmentation of carbohydrate metabolism between different cell types, using mainly our studies on leaves of temperate C3 gramineae. Here we present evidence of significant differences in carbon metabolism between epidermis, mesophyll, bundle sheath and vasculature based upon both single-cell sampling and immunolocalisation. The implications of these differences for the control of metabolism in leaves are discussed.

Effects of different ammoniacal nitrogen sources on N-metabolism of the atmospheric bromeliad Tillandsia pohliana Mez

Increasing levels of atmospheric ammonia from anthropogenic sources have become a serious problem for natural vegetation. Short-term effects of different ammoniacal sources on the N metabolism of Tillandsia pohliana, an atmospheric bromeliad, were investigated. One-year-old, aseptically grown plants were transferred to a modified Knudson medium lacking N for three weeks. Plants were subsequently transferred to Knudson media supplemented with 0.5, 1.0, or 1.5 mM of N in the forms of NH3 or NH4+ as the sole N source. The activities of glutamine synthetase (GS) and glutamate dehydrogenase (GDH-NADH) were determined after 40 h. The GS activity was stimulated significantly by increasing the levels of the gaseous form. The GDH-NADH activity increased significantly under increasing N concentrations with NH3, while no significant differences were observed with NH4+ as a N source. These results may reflect a faster NH3 absorption by T. pohliana compared to NH4+ uptake. The increased activity of GDH-NADH in NH3 treatment may play a role in protecting the cells from the toxic effects of increased endogenous level of free ammonium. A raise in the concentration of N, especially in the form of NH3, greatly increased the content of free amino acids and soluble proteins. A possible utilisation of T. pohliana to evaluate the changes of atmospheric gaseous ammonia is proposed.

An overview of lignin metabolism and its effect on biomass recalcitrance

Lignin, after cellulose, is the second most abundant biopolymer on Earth, accounting for 30% of the organic carbon in the biosphere. It is considered an important evolutionary adaptation of plants during their transition from the aquatic environment to land, since it bestowed the early tracheophytes with physical support to stand upright and enabled long-distance transport of water and solutes by waterproofing the vascular tissue. Although essential for plant growth and development, lignin is the major plant cell wall component responsible for biomass recalcitrance to industrial processing. The fact that lignin is a non-linear aromatic polymer built with chemically diverse and poorly reactive linkages and a variety of monomer units precludes the ability of any single enzyme to properly recognize and degrade it. Consequently, the use of lignocellulosic feedstock as a renewable and sustainable resource for the production of biofuels and bio-based materials will depend on the identification and characterization of the factors that determine plant biomass recalcitrance, especially the highly complex phenolic polymer lignin. Here, we summarize the current knowledge regarding lignin metabolism in plants, its effect on biomass recalcitrance and the emergent strategies to modify biomass recalcitrance through metabolic engineering of the lignin pathway. In addition, the potential use of sugarcane as a second-generation biofuel crop and the advances in lignin-related studies in sugarcane are discussed.

Diurnal changes in storage carbohydrate metabolism in cotyledons of the tropical tree Hymenaea courbaril L. (Leguminosae)

The cotyledons of Hymenaea courbaril store large amounts of xyloglucan, a cell wall polysaccharide that is believed to serve as storage for the period of seedling establishment. During storage mobilisation, xyloglucan seems to be degraded by a continuous process that starts right after radicle protrusion and follows up to the establishment of photosynthesis. Here we show evidence that events related to the hydrolases activities and production (α-xylosidase, β-galactosidase, β-glucosidase and xyloglucan endo-β-transglucosilase) as well as auxin, showed changes that follow the diurnal cycle. The period of higher hydrolases activities was between 6pm and 6am, which is out of phase with photosynthesis. Among the enzymes, α-xilosidase seems to be more important than β-glucosidase and β-galactosidase in the xyloglucan disassembling mechanism. Likewise, the sugars related with sucrose metabolism followed the rhythm of the hydrolases, but starch levels were shown to be practically constant. A high level of auxin was observed during the night, what is compatible with the hypothesis that this hormone would be one of the regulators of the whole process. The probable biological meaning of the existence of such a complex control mechanism during storage mobilisation is likely to be related to a remarkably high level of efficiency of carbon usage by the growing seedling of Hymenaea courbaril, allowing the establishment of very vigorous seedlings in the tropical forest.