In assessing biological UV-B effects,natural fluctuations of solar radiation should be taken into account

Daily and weekly fluctuations of PAR, UV-A, and UV-B have been continuously monitored for 5 months in Ancient Korinthos, Greece (37°58 N, 23°0 E) using a calibrated instrument based on 3 sharp band sensors. Daily dose ranged between 521–12 006 kJ m^-2 for PAR; 52–1, 239 kJ m^-2 for UV-A; and 0.66–22.5 kJ m² for UV-B. Weekly dose ranged between 16 778-81 788 kJ m^-2 for PAR; 1 406–8 517 kJ m^-2 for UV-A; and 18–151 kJ m^-2 for UV-B. UV-B/PAR and UV-A/PAR ratio distribution, however, does not follow closely PAR fluctuations. Generally, the UV-B/PAR and UV-A/PAR ratios were high in bright light conditions (2.1×10^-3, 118×10^-3) and low in darker weeks (0.9×10^-3, 63×10^-3. The UV-B/UV-A ratio exhibits smaller fluctuations with season (20x1×10^-3, 12×10^-3). Attention is drawn to the effects of sudden changes in ambient radiation and to the ratios of UV-B, UV-A, and PAR.     

The predators' complex of pear-feeding psyllids in unsprayed wild pear trees in greece

Four insect species producing honeydew, exploited by bees, were found on wild pear trees,Pyrus amygdaliformis Vill.. Three of them were Psyllids,Cacopsylla (Hepatopsylla) notata (Flor),Cacopsylla (Thamnopsylla) pyrisuga (Förster), Cacopsylla (Hepatopsylla) pyri (L.), and one was Aphid,Dysaphis pyri D.d.F. The 1 rst one was the most abundant. Although these species are producing honeydew from spring to autumn, the bees are foraging on it only during September and October, and not every year. A total of 18 predatory species were counted. Five of them,Anthocoris nemoralis F.,Atractotomus mali Mey.,Chrysoperla carnea (Stephens),Anisochrysa flavifrons (Brauer) andAnisochrysa prasina (Burmeister) were bred in laboratory on the Psyllids. It seems that the predators of theseHomoptera may be able to cause a decrease of their population level. Three predators,Anthocoris nemoralis F.,Chrysoperla carnea (Stephens) andCoccinella septempuctata L., were very common, and the last 2 were present almost all the year round.     

The application of a micro-algal/bacterial biofilter for the detoxification of copper and cadmium metal wastes

In the present study the potential of a biofilter containing a mixture of dried micro-algal/bacterial biomass for removing heavy metals (Cu²⁺, Cd²⁺) from dilute electroplating waste was tested. The biomass was produced in an artificial stream using the effluent of a municipal waste water treatment plant as a nutrient source, with the additional benefit of reducing phosphorus and nitrogen loadings. Baseline batch experiments determined that optimum adsorption for both metals (80–100%) were achieved with the deionized-H₂O conditioned biomass at initial pH 4.0. Other biosorption variables (contact time, initial metal concentration) were also tested. Biosorption data were fitted successfully by the Langmuir model and results showed a high affinity of the used biomass for both metals (q_max 18–31 mg metal/g.d.w). Flow-through column experiments containing Ca-alginate/biomass beads showed that metal adsorption depends also on flow-rate and volume of treated waste. Desorption of both metals with weak acids was very successful (95–100%) but the regeneration of the columns was not achieved due to the destabilization of beads.     

Photoinhibition by solar radiation in the Mediterranean alga Peyssonnelia squamata measured on site

Photoinhibition of photosynthesis, defined as reversible decrease in the effective photosynthetic quantum yield, was measured in the Mediterranean red alga, Peyssonnelia squamata, using pulse amplitude modulation (PAM) chlorophyll fluorescence and oxygen production on site. This alga is adapted to very low fluence rates of solar radiation and is easily inhibited by exposure to excessive radiation. At high solar angles its photosynthetic capacity is impaired even in its natural habitat, in the protective shade of overhanging rocks. Oxygen production was maximal at 5 m depth and decreased to almost zero at the surface. When exposed at the surface oxygen production ceased within 16 min. The optimal photosynthetic quantum yield, defined as Fv/Fm, was about 0.45 in dark-adapted specimens. After 30 min of exposure to unattenuated solar radiation the (effective, Fv/Fm) quantum yield decreased to below 0.1. Removing solar UV (especially UV-B) significantly reduced photoinhibition: the quantum yield of a sample exposed under a UV-B cut-off filter was double that of a sample exposed to full solar radiation after 30 min exposure. Recovery from photoinhibition took several hours and was not complete after prolonged exposure (1.5 h) to direct solar radiation. The degree of photoinhibition depended on the depth at which the thalli were exposed. Recovery from photoinhibition was complete within 2 h except when the algae were exposed at the surface. When measured over the whole day, the effective photosynthetic quantum yield significantly decreased by about 25% from initially high values toward early afternoon and rose again towards evening. The data indicate that this alga is adapted to very low irradiances and is easily inhibited by excessive solar radiation; solar UV contributes substantially to the observed photoinhibition.     

Alternative splicing of the IIICS domain in fibronectin governs the role of the heparin II domain in fibrillogenesis and cell spreading

The Heparin (Hep) II-binding domain of fibronectin regulates the formation of focal adhesions and actin stress fibers and hence plays an important role in cell spreading, migration, and fibronectin fibrillogenesis. Using human skin fibroblast cultures, we demonstrate that alternative splicing of the neighboring IIICS domain may regulate the activities of the Hep II domain in cell spreading and fibronectin fibrillogenesis. Recombinant Hep II domains, adjacent to either the IIICS domain or the H89 splice variant that contains the amino-terminal sequence of the IIICS domain, blocked fibronectin fibrillogenesis and required sulfated proteoglycans to mediate cell spreading. If the Hep II domain was adjacent to either the H0 or H95 splice variants, which both lack the amino terminus of the IIICS domain, fibrillogenesis was not inhibited and cell spreading was independent of a sulfated proteoglycan-mediated mechanism. The effect of the splice variants on the Hep II domain could be mimicked using a Hep II domain that contained only 6 amino acids from the III(15) repeat or 10 amino acids from the IIICS domain suggesting that sequences proximal to the III(14) repeat determined the role of the Hep II domain in these processes. We propose that alternative splicing of the IIICS domain modulates interactions between heparan sulfate proteoglycans and the Hep II domain and that this serves as a mechanism to control the biological activities of fibronectin.     

Photosynthetic Fluorescence Induction and Oxygen Production in Corallinacean Algae Measured on Site

Photoinhibition of photosynthesis was measured in two Mediterranean Corallinaceae, Jania rubens and Corallina mediterranea, using pulse-amplitude modulation (PAM) fluorescence and oxygen production on site. Both algae were found to be adapted to low irradiances of solar radiation and easily inhibited by exposure to excessive radiation. Both algae were impaired even in their natural habitat under overhanging rocks which protected them from direct solar radiation, except for a few hours in the early morning. Recovery from photoinhibition of both the photosynthetic quantum yield, defined as F_v′/F_m′, and oxygen production took several hours and was not complete. Judging from both parameters indicated above, Jania seems to be even more sensitive than Corallina, even though the former alga was found in more exposed habitats.     

Petroleum hydrocarbon bioremediation: sampling and analytical techniques, in situ treatments and commercial microorganisms currently used

The sampling and analytical methods, along with available microorganisms, used for in situ hydrocarbon bioremediation are reviewed. Each treatment method is briefly described and its advantages and limitations pertaining to potential applications are evaluated. Bioremediation provides cost-effective, contaminant- and substrate-specific treatments equally successful in reducing the concentrations of single compounds or mixtures of biodegradable materials. In situ treatments rarely yield undesirable byproducts, but precautions and preliminary baseline tests are always recommended. Sampling methods should adhere to good laboratory and field practices and usually do not require highly trained personnel. Analytical methods vary in sensitivity, cost, duration of sample analysis and personnel training required. Voucher specimens of bacterial strains used in bioremediation exist in various repositories (e.g. ATCC, DSM, etc.) or are commercially available, and are usually covered by patent rights. Each one of these strains may yield spectacular results in vitro for specific target compounds. However, the overall success of such strains in treating a wide range of contaminants in situ remains limited. The reintroduction of indigenous microorganisms isolated from the contaminated site after culturing seems to be a highly effective bioremediation method, especially when microorganism growth is supplemented by oxygen and fertilizers. Received: 10 June 1997 / Received revision: 14 August 1997 / Accepted: 25 August 1997     

Cellulose, hemicelluloses, lignin and ash content of some organic materials and their suitability for use as paper pulp supplements

Freshwater algal biomass and orange and lemon peels were assessed as tissue paper pulp supplements. Cellulose and hemicellulose contents of algal biomass were 7.1% and 16.3%, respectively, whereas for citrus peels cellulose content ranged from 12.7% to 13.6% and hemicellulose from 5.3% to 6.1%. For all materials, lignin and ash content was 2% or lower, rendering them suitable for use as paper pulp supplements. The addition of algal biomass to paper pulp increased its mechanical strength significantly. However, brightness was adversely affected by chlorophyll. The addition of citrus peels in paper pulp had no effect on breaking length, increased bursting strength and decreased tearing resistance. Brightness was negatively affected at proportions of 10%, because citrus peel particles behave as coloured pigments. The cost of both materials is about 45% lower than that of conventional pulp, resulting in a 0.9-4.5% reduction in final paper price upon their addition to the pulp.     

Prognostic Value of the Interaction between Galectin-3 and Antigen Carbohydrate 125 in Acute Heart Failure

Aims

Galectin-3 (Gal-3) and carbohydrate antigen 125 (CA125) have emerged as robust prognostic biomarkers in heart failure. Experimental data have also suggested a potential molecular interaction between CA125 and Gal-3; however, the biological and clinical relevance of this interaction is still uncertain. We sought to evaluate, in patients admitted for acute heart failure, the association between plasma Gal-3 with all-cause mortality and the risk for rehospitalizations among high and low levels of CA125.

Methods and Results

We included 264 consecutive patients admitted for acute heart failure to the Cardiology Department in a third-level center. Both biomarkers were measured on admission. Negative binomial and Cox regression models were used to evaluate the prognostic effect of the interaction between Gal-3 and CA125 (dichotomized by its median) with hospital readmission and all-cause mortality, respectively. During a median follow-up of 2 years (IQR = 1-2.8), 108 (40.9%) patients deaths and 365 rehospitalizations in 171 (69.5%) patients were registered. In a multivariable setting, the effect of Gal-3 on mortality and rehospitalization was differentially mediated by CA125 (p = 0.007 and p<0.001, respectively). Indeed, in patients with CA125 above median (>67 U/ml), values across the continuum of Gal-3 showed a positive and almost linear relationship with either the risk of death or rehospitalization. Conversely, when CA125 was below median (≤67 U/ml), Gal-3 lacked any prognostic effect on both endpoints.

Conclusion

In patients with acute heart failure, Gal-3 was strongly associated with higher risk of long-term mortality and repeated rehospitalizations, but only in those patients exhibiting higher values of CA125 (above 67 U/ml).     

Effects of solar radiation and solar radiation deprived of UV-B and total UV on photosynthetic oxygen production and pulse amplitude modulated fluorescence in the brown alga Padina pavonia

Abstract: The effects of solar radiation on photosynthetic oxygen production and pulse amplitude modulated (PAM) fluorescence were measured in the marine brown macroalga Padina pavonia harvested from different depths from the Greek coast near Korinth. In fluence rate-response curves the light compensation point for photosynthetic oxygen production increased and the saturation level decreased with increasing exposure time to solar radiation. Cutting off the UV-B wavelength range (280–315 nm) from solar radiation reduced the inhibition of photosynthesis, and the organisms were less affected when all of the UV radiation was filtered out. Algae collected from 7 m depth were much more prone to photoinhibition than those harvested from rock pools exposed to unfiltered solar radiation. During continuous exposure to solar radiation, rock pool algae showed photoinhibition after longer periods of time than specimens from 7 m or from dark adapted habitats. When subjected to unfiltered solar radiation the ratio of the variable fluorescence to the maximal fluorescence     (F_v = F_m− F_o) rapidly declined with increasing exposure time. However, again algae from 7 m depth were more prone to photoinhibition than rock pool algae. The differences between the two ecological strains were less obvious when UV-B or total UV was removed from solar radiation. Only in the latter case a complete recovery was observed after 2 h while, when exposed to unifiltered sunlight, only the rock pool algae recovered completely within that time.