Acidification: its impact on the environment and mitigation strategies

The effect of acidification on ecosystems is reviewed. About 30% of the world land area is acidified mostly by natural processes. Only a small part of it is acidified from pollution which leads to extensive forest and surface water deterioration in Europe and North America. The damage is especially visible in areas of poor soil quality. The acid deposition pattern is characterized, with a special emphasis on Poland. It was shown that strategies for mitigation of ecosystem acidification lead to a decrease of SO₂ emissions due to the use of lower sulphur content fuels and application of desulphurisation methods. Also, a decrease in NO_x emissions is observed due to use of catalysts and application of NO_x removal technologies. However, since about 50% of NO_x emission is from vehicles, this improvement is offset by a continuously increasing vehicle population. The application of liming, forest fertilisation and suitable land use for mitigation of ecosystem acidification is also reviewed.     

Effect of malaria in pregnancy on foetal cortical brain development: a longitudinal observational study

ABSTRACT: BACKGROUND: Malaria in pregnancy has a negative impact on foetal growth, but it is not known whether this also affects the foetal nervous system. The aim of this study was to examine the effects of malaria on foetal cortex development by three-dimensional ultrasound. METHODS: Brain images were acquired using a portable ultrasound machine and a 3D ultrasound transducer. All recordings were analysed, blinded to clinical data, using the 4D view software package. The foetal supra-tentorial brain volume was determined and cortical development was qualitatively followed by scoring the appearance and development of six sulci. Multilevel analysis was used to study brain volume and cortical development in individual foetuses, RESULTS: Cortical grading was possible in 161 out of 223 (72%) serial foetal brain images in pregnant women living in a malaria endemic area. There was no difference between foetal cortical development or brain volumes at any time in pregnancy between women with immediately treated malaria infections and non-infected pregnancies. CONCLUSION: The percentage of images that could be graded was similar to other neuro-sonographic studies. Maternal malaria does not have a gross effect on foetal brain development, at least in this population, which had access to early detection and effective treatment of malaria.     

Remarques sur l'endemisme dans la flore des Alpes et des Carpates

Sans résumé     

Complex Interactions between soil-transmitted helminths and malaria in pregnant women on the Thai-Burmese border

Background

Deworming is recommended by the WHO in girls and pregnant and lactating women to reduce anaemia in areas where hookworm and anaemia are common. There is conflicting evidence on the harm and the benefits of intestinal geohelminth infections on the incidence and severity of malaria, and consequently on the risks and benefits of deworming in malaria affected populations. We examined the association between geohelminths and malaria in pregnancy on the Thai-Burmese border.

Methodology

Routine antenatal care (ANC) included active detection of malaria (weekly blood smear) and anaemia (second weekly haematocrit) and systematic reporting of birth outcomes. In 1996 stool samples were collected in cross sectional surveys from women attending the ANCs. This was repeated in 2007 when malaria incidence had reduced considerably. The relationship between geohelminth infection and the progress and outcome of pregnancy was assessed.

Principal Findings

Stool sample examination (339 in 1996, 490 in 2007) detected a high prevalence of geohelminths 70% (578/829), including hookworm (42.8% (355)), A. lumbricoides (34.4% (285)) and T.trichuria (31.4% (250)) alone or in combination. A lower proportion of women (829) had mild (21.8% (181)) or severe (0.2% (2)) anaemia, or malaria 22.4% (186) (P.vivax monoinfection 53.3% (101/186)). A. lumbricoides infection was associated with a significantly decreased risk of malaria (any species) (AOR: 0.43, 95% CI: 0.23–0.84) and P.vivax malaria (AOR: 0.29, 95% CI: 0.11–0.79) whereas hookworm infection was associated with an increased risk of malaria (any species) (AOR: 1.66, 95% CI: 1.06–2.60) and anaemia (AOR: 2.41, 95% CI: 1.18–4.93). Hookworm was also associated with low birth weight (AOR: 1.81, 95% CI: 1.02–3.23).

Conclusion/Significance

A. lumbricoides and hookworm appear to have contrary associations with malaria in pregnancy.     

Contributions of evaporation, isotopic non-steady state transpiration and atmospheric mixing on the delta18O of water vapour in Pacific Northwest coniferous forests

Changes in the ²H and ¹⁸O of atmospheric water vapour provide information for integrating aspects of gas exchange within forest canopies. In this study, we show that diurnal fluctuations in the oxygen isotope ratio (δ¹⁸O) as high as 4‰ were observed for water vapour (δ¹⁸O_vp) above and within an old‐growth coniferous forest in the Pacific Northwest region of the United States. Values of δ¹⁸O_vp decreased in the morning, reached a minimum at midday, and recovered to early‐morning values in the late afternoon, creating a nearly symmetrical diurnal pattern for two consecutive summer days. A mass balance budget was derived and assessed for the ¹⁸O of canopy water vapour over a 2‐d period by considering the ¹⁸O‐isoflux of canopy transpiration, soil evaporation and the air entering the canopy column. The budget was used to address two questions: (1) do δ¹⁸O values of canopy water vapour reflect the biospheric influence, or are such signals swamped by atmospheric mixing? and (2) what mechanisms drive temporal variations of δ¹⁸O_vp? Model calculations show that the entry of air into the canopy column resulted in an isotopically depleted ¹⁸O‐isoflux in the morning of day 1, causing values of δ¹⁸O_vp to decrease. An isotopically enriched ¹⁸O‐isoflux resulting from transpiration then offset this decreased δ¹⁸O_vp later during the day. Contributions of ¹⁸O‐isoflux from soil evaporation were relatively small on day 1 but were more significant on day 2, despite the small H₂¹⁶O fluxes. From measurements of leaf water volume and sapflux, we determined the turnover time of leaf water in the needles of Douglas‐fir trees as ≈ 11 h at midday. Such an extended turnover time suggests that transpiration may not have occurred at the commonly assumed isotopic steady state. We tested a non‐steady state model for predicting δ¹⁸O of leaf water. Our model calculations show that assuming isotopic steady state increased isoflux of transpiration. The impact of this increase on the modelled δ ¹⁸O_vp was clearly detectable, suggesting the importance of considering isotopic non‐steady state of transpiration in studies of forest ¹⁸O water balance.     

Effect of thalidomide affecting VEGF secretion, cell migration, adhesion and capillary tube formation of human endothelial EA.hy 926 cells

Angiogenesis, new blood vessel formation, is a multistep process, precisely regulated by pro-angiogenic cytokines, which stimulate endothelial cells to migrate, proliferate and differentiate to form new capillary microvessels. Excessive vascular development and blood vessel remodeling appears in psoriasis, rheumatoid arthritis, diabetic retinopathy and solid tumors formation. Thalidomide [alpha-(N-phthalimido)-glutarimide] is known to be a potent inhibitor of angiogenesis, but the mechanism of its inhibitory action remains unclear. The aim of the study was to investigate the potential influence of thalidomide on the several steps of angiogenesis, using in vitro models. We have evaluated the effect of thalidomide on VEGF secretion, cell migration, adhesion as well as in capillary formation of human endothelial cell line EA.hy 926. Thalidomide at the concentrations of 0.01 microM and 10 microM inhibited VEGF secretion into supernatants, decreased the number of formed capillary tubes and increased cell adhesion to collagen. Administration of thalidomide at the concentration of 0.01 microM increased cell migration, while at 10 microM, it decreased cell migration. Thalidomide in concentrations from 0.1 microM to 10 microM did not change cell proliferation of 72-h cell cultures. We conclude that anti-angiogenic action of thalidomide is due to direct inhibitory action on VEGF secretion and capillary microvessel formation as well as immunomodulatory influence on EA.hy 926 cells migration and adhesion.     

Reaction of acrolein with 2'-deoxyadenosine and 9-ethyladenine--formation of cyclic adducts

Treatment of 2'-deoxyadenosine with acrolein at pH 4.6 in 37 degrees C affords unstable adducts containing either one or two fused ring systems where the hydroxypropano units are derived from acrolein. Since the use of 2'-deoxyadenosine resulted in the creation of at least four diastereoisomers for the adduct made up of two fused rings, therefore, for identification and assignment of the products, 9-ethyladenine was used instead as the starting material in the reaction. The products, 3E and 4E, were structurally characterised by UV, mass spectrometry and NMR spectroscopy.     

Cellular and mitochondrial iron homeostasis in vertebrates

Iron plays an essential role in cellular metabolism and biological processes. However, due to its intrinsic redox activity, free iron is a potentially toxic molecule in cellular biochemistry. Thus, organisms have developed sophisticated ways to import, sequester, and utilize iron. The transferrin cycle is a well-studied iron uptake pathway that is important for most vertebrate cells. Circulating iron can also be imported into cells by mechanisms that are independent of transferrin. Once imported into erythroid cells, iron is predominantly consumed by the mitochondria for the biosynthesis of heme and iron sulfur clusters. This review focuses on canonical transferrin-mediated and the newly discovered, non-transferrin mediated iron uptake pathways, as well as, mitochondrial iron homeostasis in higher eukaryotes. This article is part of a Special Issue entitled: Cell Biology of Metals.