Effects of air pollutants on the wintertime water economy of the Scots pine Pinus silvestris

The changes effected by air-borne pollutants in the wintertime water economy of the Scots pine were investigated in industrial and urban environments in Oulu (65°N). Pine needles were found to undergo a wintertime water stress, which was more intense in the polluted area than in the less polluted environment. The water stress of the needles was found to be the more severe, the more pollutants had accumulated in the needles. In the needles of the trees growing in the polluted area, transpiration started shortly after they had been brought into laboratory even at midwinter, but the healthy trees were not equally sensitive in their response. When the weight loss of branches was observed in outdoor conditions, it was noted that the branches brought from the polluted area lost weight more rapidly than the branches of the healthy area. Air-borne pollutants hence constitute an obvious additional risk to the wintering of plants, particularly their water economy.     

Light penetration in different types of lakes in Central Finland

Light penetration measurements of blue (Schott filter BG 12), green (VG 9), and red (RG 630) light was made in 30 Finnish lakes with different degree of humus content and eutrophy for the comparison of the structure of phytoplankton communities and the light environment in the waters.
The relations between Secchi disc visibility and the penetrations of different spectral regions and relations between the light conditions and the colour of the water was examined.
The increase of ɛ_min m₋₁ caused by humus material is 0.008 In units per colour unit (mg Pt l⁻¹). The optical depth was especially in brown waters smaller than calculated by Formula after Talling (1965).     

Preceding infection as an important risk factor for ischaemic brain infarction in young and middle aged patients

The role of preceding infection as a risk factor for ischaemic stroke was investigated in a case-control study of 54 consecutive patients under 50 years of age with brain infarction and 54 randomly selected controls from the community matched for sex and age. Information about previous illnesses, smoking, consumption of alcohol, and use of drugs was taken. A blood sample was analysed for standard biochemical variables and serum cholesterol, high density lipoprotein cholesterol, triglyceride, and fasting blood glucose concentrations determined. Titres of antimicrobial antibodies against various bacteria, including Staphylococcus, Streptococcus, Yersinia, and Salmonella and several viruses were determined. Febrile infection was found in patients during the month before the brain infarction significantly more often than in controls one month before their examination (19 patients v three controls; estimated relative risk 9·0 (95% confidence interval 2·2 to 80·0)). The most common preceding febrile infection was respiratory infection (80%). Infections preceding brain infarction were mostly of bacterial origin based on cultural, serological, and clinical data. In conditional logistic regression analysis for matched pairs the effect of preceding febrile infection remained significant (estimated relative risk 14·5 (95% confidence interval 1·9 to 112·3)) when tested with triglyceride concentration, hypertension, smoking, and preceding intoxication with alcohol.Although causality cannot be inferred from these data and plausible underlying mechanisms remain undetermined, preceding febrile infection may play an important part in the development of brain infarction in young and middle aged patients.     

Receptor for advanced glycation end products plays a more important role in cellular survival than in neurite outgrowth during retinoic acid-induced differentiation of neuroblastoma cells.

The receptor for advanced glycation end products (RAGE), a member of the immunoglobulin superfamily, is known to interact with amphoterin. This interaction has been proposed to play a role in neurite outgrowth and process elongation during neurodifferentiation. However, there is as yet no direct evidence of the relevance of this pathway to neurodifferentiation under physiological conditions. In this study we have investigated a possible role of RAGE and amphoterin in the retinoic acid-induced differentiation of neuroblastoma cells. The functional inactivation of RAGE by dominant negative and antisense strategies showed that RAGE is not required for process outgrowth or differentiation, although overexpression of RAGE accelerates the elongation of neuritic processes. Using the antisense strategy, amphoterin was shown to be essential for process outgrowth and differentiation, suggesting that amphoterin may interact with other molecules to exert its effect in this context. Interestingly, the survival of the neuroblastoma cells treated with retinoic acid was partly dependent on the expression of RAGE, and inhibition of RAGE function partially blocked the increase in anti-apoptotic protein Bcl-2 following retinoic acid treatment. Based on these results we propose that a combination therapy using RAGE blockers and retinoic acid may prove as a useful approach for chemotherapy for the treatment of neuroblastoma.     

Effect of ozone exposure on polyamines in Scots pine trees

Effects of ozone exposure on polyamines in Pinus sylvestris L. were studied in a long-term experiment. Ten- to 15-year-old Scots pines were exposed to target ozone levels which began at ambient + 40 ppb in May, decreasing to ambient air only by September for 3 growing seasons. The amount of ozone applied followed the natural pattern of variation in ozone concentrations in Northern Finland. The free, soluble conjugated and insoluble conjugated polyamines were analyzed during the experiment and shortly after termination of exposure as well as at the beginning of the following growing season. A carry-over effect was observed as ozone-induced reduction of free spermidine in the oldest needle year class, which developed during the first exposure season of the experiment. This reduction was observed both after the second and the third ozone exposure season. Conversely, after termination of the experiment, levels of free polyamines increased in the following growing season, and soluble conjugated polyamines decreased in the developing needles. The post-treatment changes in polyamine concentrations are hypothesized to be caused by stress-induced injuries or delayed recovery of metabolic processes rather than protective responses. It is noteworthy that some responses in polyamines were found in the developing needles nine months after terminating the ozone exposure. This suggests that stress-induced injuries to older needles affected metabolism of new developing needles.     

Do elevations in temperature,CO2, and nutrient availability modify belowground carbon gain and root morphology in artificially defoliated silver birch seedlings?

Climate warming increases the risk of insect defoliation in boreal forests. Losses in photosynthetically active surfaces cause reduction in net primary productivity and often compromise carbon reserves of trees. The concurrent effects of climate change and removal of foliage on root growth responses and carbohydrate dynamics are poorly understood, especially in tree seedlings. We investigated if exposures to different combinations of elevated temperature, CO₂, and nutrient availability modify belowground carbon gain and root morphology in artificially defoliated 1‐year‐old silver birches (Betula pendula). We quantified nonstructural carbohydrates (insoluble starch as a storage compound; soluble sucrose, fructose, and glucose) singly and in combination in fine roots of plants under winter dormancy. Also the total mass, fine root proportion, water content, and length of roots were defined. We hypothesized that the measured properties are lower in defoliated birch seedlings that grow with ample resources than with scarce resources. On average, fertilization markedly decreased both the proportion and the carbohydrate concentrations of fine roots in all seedlings, whereas the effect of fertilization on root water content and dry mass was the opposite. However, defoliation mitigated the effect of fertilization on the root water content, as well as on the proportion of fine roots and their carbohydrate concentrations by reversing the outcomes. Elevation in temperature decreased and elevation in CO₂ increased the absolute contents of total nonstructural carbohydrates, whereas fertilization alleviated both these effects. Also the root length and mass increased by CO₂ elevation. This confirms that surplus carbon in birch tissues is used as a substrate for storage compounds and for cell wall synthesis. To conclude, our results indicate that some, but not all elements of climate change alter belowground carbon gain and root morphology in defoliated silver birch seedlings.     

Effects of warming climate on early-season carbon allocation and height growth of defoliated mountain birches

Tree carbohydrate reserves are usually compromised following insect outbreak, which results in a delay in leaf emergence and a reduction in growth, especially in cold environments. However, in recent times, severe defoliation of subarctic mountain birches (Betula pubescens ssp. czerepanovii) by the winter moth (Operophtera brumata) has not induced such responses. This may be the result of a warming climate stimulating plant primary metabolism. We examined if increasing thermal sum (sum of daily mean temperatures above +5 °C, d.d.) and complete foliage loss affected the concentrations of carbohydrates in sap, juvenile leaves, and fine roots of mountain birches in northern Finland and Norway. The sampling was conducted at the beginning of the growing season, two years after the insect outbreak. We also investigated the morphologic properties of mature leaves and the shoot growth of the trees. Our results showed that the carbohydrate concentrations in leaves and roots (averages 67.8 and 12.5 mg g^?1 DW, respectively) decreased in defoliated trees with increasing thermal sum (>400 d.d.), whereas the response in intact trees was the opposite. The carbohydrates in the sap were unaffected by defoliation or thermal sum accumulation. The leaf area of mature leaves and the height growth of long shoots were greater in trees at warmer sites, irrespective of defoliation. However, defoliation increased the leaf weight per area (SLW: specific leaf weight). We conclude that under warmer growing conditions, low early-season leaf and fine root carbohydrate concentrations of previously defoliated trees cannot be used as indicators of aboveground growth.     

Photosynthesis, temperature and radial growth of Scots pine in northern Finland: identifying the influential time intervals

We analyzed the statistical dependence between temperature, the state of functional substances (S), estimated photosynthetic production and the radial growth of Scots pine in northern Finland. Annual sums of these variables were calculated for intervals consisting of consecutive calendar days. For daily mean temperature, all possible intervals between 1 April of the previous year and 31 August of the current year were tested. For S and the daily photosynthetic production, the tested range included days from April to October of the previous year and from April to August of the current year. These sums were compared with tree-ring indices using the Pearson correlation coefficient over the period 1906–2002. The highest correlations (r = 0.64) between daily mean temperature and growth indices were obtained for current-year periods starting 22 June and ending 28 July. For S, a temperature-derived variable describing the instantaneous photosynthetic capacity of Scots pine, the respective interval was from 5 July to 31 July (r = 0.63). The daily photosynthetic production of Scots pine was estimated for 1906–2002 using the PhenPhoto model. The interval during which the estimated daily photosynthetic production of Scots pine produced the highest correlation with growth indices (r = 0.56) was from 5 July to 27 July. Previous-year values of each variable were also significantly correlated to annual growth indices. The intervals with highest correlations were in May–June for each variable, and the correlations were rather low—between 0.3 and 0.4. We also tested selection criteria based on intervals that do not consist of consecutive calendar days, but results did not show notable improvements over the customarily used continuous intervals.     

Chemiluminescence of non‐differentiated THP‐1 promonocytes: developing an assay for screening anti‐inflammatory milk proteins and peptides

Human leukemic THP‐1 promonocytes are widely used as a model for peripheral blood monocytes. However, superoxide production during respiratory burst (RB) of non‐differentiated THP‐1 (nd‐THP‐1) cells is very low. Here we present a rapid and low‐cost method for measuring the chemiluminescence (CL) of opsonized zymosan (OZ) induced RB which allows detection of Escherichia coli lipopolysaccharide (LPS) induced priming of nd‐THP‐1 cells on the basis of CL reaction kinetics. Maximum CL intensity obtained was 2.20 ± 0.25 and 1.30 ± 0.11 relative light units, while CL peak time was achieved at 18.1 ± 2.6 and 28.7 ± 1.3 min in primed and non‐primed cells, respectively. The priming of nd‐THP‐1 cells with LPS evoked typical TNF‐α and IL‐6 production. We tested the effects of bovine lactoferrin and protein fractions from Lactobacillus helveticus BGRA43 fermented milk for potential anti‐inflammatory effects on LPS primed nd‐THP‐1 cells. Four fractions were found to inhibit the OZ‐induced CL in a dose‐dependent manner (IC₅₀ 3–30 µg/mL), while lactoferrin inhibited CL to a lesser extent (IC₅₀ 270 µg/mL). These results suggest that measuring CL response of nd‐THP‐1 cells can serve as a method for screening anti‐inflammatory compounds which could be used in reducing the risk of phagocyte‐mediated inflammatory diseases. Copyright © 2010 John Wiley & Sons, Ltd.     

On Optical Properties of Dilute Colloidal Gold

Wavelength-dependent complex effective refractive index of dilute colloidal gold, i.e., spherical gold nanoparticles in water was measured using a reflectometer and a spectrophotometer. The spectral data obtained was used for the calculation of the wavelength-dependent complex permittivity of the gold nanoparticle with the aid of the Maxwell Garnett effective medium model for the colloid. It is shown that the wavelength-dependent complex permittivity of gold nanoparticle is different from the complex permittivity of bulk gold. Furthermore, Smakula’s formula is introduced for the calculation of the relative concentration of gold nanoparticles embedded in liquid using absorption data of the colloid.