Influence of roadside pollution on the phylloplane microbial community of Alnus nepalensis (Betulaceae)

The North Eastern region of India is undergoing industrial development at a faster rate than expected. Roads form the main system of transportation and communication owing to the hilly topography of the region. Automobiles discharge a number of gaseous and trace metal contaminants. Human activities like stone grinding, road construction and sand milling also increase the atmospheric dust and heavy metal contaminant level. These contaminants get settled on leaf surfaces at roadsides and enter in contact with phylloplane microorganisms. This study compares microorganisms on leaf surfaces of alder (Alnus nepalensis (Betulaceae)) on roadside and non-roadside environments. Two sites dominated by alder were selected. One at a busy road intersection on the National Highway no. 44 in Shillong with high traffic density (8 000-9 000 heavy vehicles/day), taken as the polluted site and the other one in a forest approximately 500 m away from the roadside considered as the unpolluted site. Analysis of phylloplane microorganisms, lead, zinc, copper, cadmium and sulphur was carried out from leaves. The bacterial population was higher at the unpolluted site. Bacterial population showed a significant negative correlation with lead, zinc, copper, cadmium and sulphur. Similarly, fungal population was higher at the unpolluted site. A total of 29 fungal species were isolated from the phylloplane of A. nepalensis (polluted site 16 species; unpolluted site 28 species). Some fungal forms like Mortierella sp., Fusarium oxysporum and Aureobasidium pollulans were dominant in the polluted site. Numbers of phylloplane fungi and bacteria were significantly reduced in the polluted site. The correlation coefficient indicated a detrimental effect of metals like lead, zinc, copper, cadmium and sulphur on the microbial community of leaf surfaces. The specificity of certain fungi to the unpolluted site may be attributed to their sensitivity to pollution. The predominance of Aureobasidium pollulans, Fusarium oxysporum and Mortierella sp. in the polluted site may be due to their resistance to pollutants in roadside conditions. Rev. Biol. Trop. 56 (3): 1521-1529. Epub 2008 September 30.

La región nororiental de la India está experimentando un rápido desarrollo industrial y debido a la topografía montañosa de la región, los automóviles descargan variedad de contaminantes. Actividades humanas como moler piedra y construir caminos también aumentan el polvo atmosférico y la contaminación con metales pesados. Este estudio compara microorganismos en superficies foliares del árbol Alnus nepalensis (Betulaceae). Se estudió uno sitio en una intersección de Shillong, con alta densidad de tráfico (8 000-9 000 vehículos pesados/día), tomada como el sitio contaminado, y otro en un bosque aproximadamente a 500 m de la carretera (sitio no contaminado). Se contabilizaron bacterias, hongos, plomo, zinc, cobre, cadmio y sulfuro. La población bacteriana era más alta en el sitio no contaminado. La población bacteriana mostró una correlación negativa significativa con el contenido de plomo, cinc, cobre, cadmio y sulfuro foliares en el sitio contaminado, mientras que en el sitio no contaminado la correlación fue insignificante. La población de hongos también fue más alta en el sitio no contaminado. Un total de 29 especies de hongos fueron aislados A. nepalensis: 16 en el sitio contaminado y 28 en el no contaminado. Algunas especies de hongos como Mortierella sp., Fusarium oxysporum y Aureobasidium pollulans fueron dominantes en el sitio contaminado. El número de hongos y bacterias fue significativamente menor en el sitio contaminado. El coeficiente de correlación indicó un efecto perjudicial de metales como el plomo, el zinc, el cobre, el cadmio y el sulfuro en esta comunidad que habitan superficies de hojas. La especificidad de ciertos hongos al sitio no contaminado se puede atribuir a su sensibilidad a la contaminación. El predominio de Aureobasidium pollulans, Fusarium oxysporum y Mortierella sp. en el sitio contaminado puede ser debido a su resistencia a los agentes contaminadores.

Effects of Air Pollutants on Childhood Asthma

Epidemiologic studies have suggested the association between environmental exposure to volatile organic compounds (VOCs) and polycyclic aromatic hydrocarbons (PAHs) and the increased risk of incurring asthma. Yet there is little data regarding the relationship between personal exposure to air pollution and the incidence of asthma in children. This study was designed to evaluate the effect of exposure to air pollution on children with asthma by using exposure biomarkers. We assessed the exposure level to VOCs by measuring urinary concentrations of hippuric acid and muconic acid, and PAHs by 1-OH pyrene and 2-naphthol in 30 children with asthma and 30 children without asthma (control). The mean level of hippuric acid was 0.158+/-0.169micromol/mol creatinine in the asthma group and 0.148+/-0.249micromol/mol creatinine in the control group, with no statistical significance noted (p=0.30). The mean concentration of muconic acid was higher in the asthma group than in the control group (7.630+/-8.915micromol/mol creatinine vs. 3.390+/-4.526micromol/mol creatinine p=0.01). The mean level of urinary 1-OHP was higher in the asthma group (0.430+/-0.343micromol/mol creatinine) than the control group (0.239+/-0.175micromol/mol creatinine), which was statistically significant (p=0.03). There was no difference in the mean concentration of 2-NAP between the two groups (9.864+/-10.037micromol/mol in the asthma group vs. 9.157+/-9.640micromol/mol in the control group, p=0.96). In conclusion, this study suggests that VOCs and PAHs have some role in asthma.

Formation of reactive oxygen species in rat epithelial cells upon stimulation with fly ash.

Fly ash was used as a model for ambient particulate matter which is under suspicion to cause adverse pulmonary health effects. The fly ash was pre-sized and contained only particles < 20 microm including an ultrafine fraction (< 100 nm) that contributed 31% to the particle number. In our study, we investigated the influence of fly ash on the promotion of early inflammatory reactions like the formation of reactive oxygen species (ROS) in rat lung epithelial cells (RLE-6TN). Furthermore, we determined the formation of nitric oxide (NO). The cells show a clear dose-response relationship concerning the formation of ROS with regard to the mass of particles applied. Lipopolysaccharide (LPS) added as a co-stimulus did not increase the formation of ROS induced by fly ash. Furthermore, in LPS (0.1 microg/ml) and tumour necrosis factor-alpha (TNF-alpha; 1 ng/ml) pre-treated cells no increase in reactive oxygen species comparable to fly ash alone is observable. In presence of the metal chelator, desferrioxamine (DFO), ROS formation can be significantly reduced. Neither fly ash nor LPS induced a significant NO release in RLE-6TN cells.

Changes in human serum antioxidant capacity and peroxidation after four months of exposure to air pollutants

Twenty-one adult volunteers (aged 27-32 years), who had been living in Mexico City for four continuous months (physicians working as fellows) were studied the first and sixteenth week of their stay in order to learn the effect of the pollutants contained in Mexico City's atmosphere on some serum biochemical parameters. The activity of serum superoxide dismutase (SOD) decreased after 16 weeks in comparison with the values obtained the first week (109.6 to 56.9 mU/mg protein; 50 percent less). In contrast, the inhibitory capacity of serum vs. induced in vitro lipoperoxidation increased in relation to the length of stay (22 percent). The serum levels of thiobarbituric-reactive material also decreased in almost 30 percent (from 6.10 to 4.12 nmol). The other lipoperoxides measured were unchanged (chromolipids and diene conjugation). We propose that this may be as a result of the adaptive capacity of the human orgnaisms, within a pollutant atmosphere in which the ozone levels might participate in a decrease of SOD activity during chronic exposure, to air pollution