Characteristics of the mutagenic and toxic effects of ethylene imine and its oligomers. Comparative study in the automated SOS-chromotest system and in standard bacterial test systems

Raising total positive charge of a chemical mutagen does increase its local concentration in the area of biological target-DNA, and, as a consequence, causes increase in the rate of interaction of a mutagen with the target. Experimental evidence of this idea has been obtained in three test systems: the Ames test, Trp+ reversions in Escherichia coli WP2 and in the automated "SOS-chromotest" system with E. coli PQ 37 ("Labsystems", Finland).     

Spatial patterns and relationships between phytoplankton, zooplankton and water quality in the Saimaa lake system, Finland

The interactions between phytoplankton and zooplankton were studied in two large lakes in the Saimaa lake system, Finland. Both are subjected to substantial waste water loading, and exhibit a clear trophic gradient between the loaded and unloaded areas. The phytoplankton and zooplankton were compared in terms of composition, abundance and biomass at 34–39 stations located in different parts of the lakes. At least four mechanisms were thought to affect the composition of plankton communities: (1) the amount of nutrients (trophic gradient), (2) grazing of algae by herbivores, (3) the effect of the algal species composition on feeding by zooplankters (large, colonial algae in the more loaded parts of the lakes) and (4) the regeneration and reorganization of nutrients.     

Acetate Degradation at 70°C in Upflow Anaerobic Sludge Blanket Reactors and Temperature Response of Granules Grown at 70°C

Anaerobic acetate degradation at 70°C and at 55°C (as a reference) was studied by running laboratory upflow anaerobic sludge blanket (UASB) reactors inoculated with mesophilic granular sludge. In UASB reactors fed with acetate-containing media (3 g of chemical oxygen demand [COD] per liter, corresponding to 47 mM acetate) approximately 50 days was needed at 70°C and less than 15 days was needed at 55°C to achieve an effluent COD of 500 to 700 mg/liter. In the UASB reactors at both 70 and 55°C up to 90% of the COD was removed. Batch assays showed that sludges from two 70°C UASB reactors, one run at a low effluent acetate concentration and the other run at a high effluent acetate concentration, exhibited slightly different responses to temperatures in the range from 37 to 70°C. Both 70°C sludges, as well as the 55°C sludge, produced methane at temperatures of 37 to 73°C. The 55°C sludge exhibited shorter lag phases than the 70°C sludges and higher specific methane production rates between 37 and 65°C.     

Carbohydrate distribution and cellular injuries in acid rain and cold-treated spruce needles

Summary The cellular structures of acid rain-irrigated needles of several provenances of Norway spruce (Picea abies L. Karst) seedlings were studied after winter experimental freezing. Frost injuries and recovery were characterized by visual damage scoring and classification of mesophyll cell alterations, also using histochemical methods for carbohydrate fluorescent staining. The treatment with-30° C during the late dormancy period was sufficient to cause significant injuries and intracellular degradation in the tissues of the green needles. The most affected seedlings in terms of visual injury scoring were found among those treated with clean water or at pH 3, while freezing injury, defined as an occlusion of phenolic substances in the central vacuole of the mesophyll cells, was most abundant in the needles from spruces irrigated either with clean water or at pH 4 or pH 3. Electron microscopy revealed the details of the injury, e. g. thinning out of the cytoplasm and chloroplast stroma, darkening of the chloroplasts and eventually swelling of the chloroplasts and protoplast. PAS and ConA reactions in the needle tissue revealed intense starch accumulation in the mesophyll and transfusion tissues as early as in March, with a tendency to increase, especially in the untreated needles during the recovery period. Plasma membrane disturbances were indicated by histochemical identification of callose deposits in the mesophyll cell walls, these being most abundant in the acid rain-treated needles. All these findings suggest that freezing at –30° C was more deleterious to the seedlings pretreated with acid or clean water than to those not given additional irrigation.     

DDT (dicophane) and postmenopausal breast cancer in Europe: case-control study.

OBJECTIVE: To examine any possible links between exposure to DDE (1,1-dichloro-2,2-bis (p-chlorophenyl)ethylene), the persistent metabolite of the pesticide dicophane (DDT), and breast cancer. DESIGN: Multicentre study of exposure to DDE by measurement of adipose tissue aspirated from the buttocks. Laboratory measurements were conducted in a single laboratory. Additional data on risk factors for breast cancer were obtained by standard questionnaires. SETTING: Centres in Germany, the Netherlands, Northern Ireland, Switzerland, and Spain. SUBJECTS: 265 postmenopausal women with breast cancer and 341 controls matched for age and centre. MAIN OUTCOME MEASURE: Adipose DDE concentrations. RESULTS: Women with breast cancer had adipose DDE concentrations 9.2% lower than control women. No increased risk of breast cancer was found at higher concentrations. The odds ratio of breast cancer, adjusted for age and centre, for the highest versus the lowest fourth of DDE distribution was 0.73 (95% confidence interval 0.44 to 1.21) and decreased to 0.48 (0.25 to 0.95; P for trend = 0.02) after adjustment for body mass index, age at first birth, and current alcohol drinking. Adjustment for other risk factors did not materially affect these estimates. CONCLUSIONS: The lower DDE concentrations observed among the women with breast cancer may be secondary to disease inception. This study does not support the hypothesis that DDE increases risk of breast cancer in postmenopausal women in Europe.     

Nitrogen,phosphorus and Daphnia grazing in controlling phytoplankton biomass and composition – an experimental study

The role of nitrogen as a factor controllingphytoplankton biomass was studied in nutrientenrichment incubations in the laboratory using waterfrom pelagic region of two mesotrophic lakes ineastern Finland, Lake Kallavesi (in year 1994) andLake Juurusvesi (in year 1995). We used differentcombinations of phosphorus and nitrogen additions ina total of eight experiments. Furthermore, we includedDaphnia grazing treatment to the experimentaldesign in Lake Juurusvesi experiments. The nitrogentreatments did not increase chlorophyll aconcentration in any of the experiments compared withthe controls. Chlorophyll a content was highestin those nutrient treatments where phosphorus wasadded with or without nitrogen. Daphnia grazingdecreased chlorophyll a concentration comparedwith non-grazed treatments. In some cases grazing alsocaused higher ammonium concentrations. Theseexperiments, as well as the nutrient ratio of the lakewater used, suggest that phosphorus is likely tocontrol the amount of phytoplankton biomass. This revised version was published online in July 2006 with corrections to the Cover Date.     

Effect of acute ethanol load on postheparin plasma lipoprotein lipase and hepatic lipase activities and intravenous fat tolerance

This study aimed to examine the possibility that ethanol-induced rise of serum triglyceride concentration in man is partly due to an impaired removal of triglycerides from the circulation. Acute ethanol loads given to normal human subjects after an overnight fast reduced the postheparin plasma lipoprotein lipase activity by an average of 25% but did not influence the postheparin plasma hepatic lipase activity or fractional removal of Intralipid triglyceride. When alcolhol was administered to fed subjects in the evening the postheparin plasma hepatic lipase was significantly decreased in the next morning as compared to corresponding control value but the lipoprotein lipase and Intralipid clearance were not changed. It is concluded that the slight decrease of lipoprotein lipase during alcohol intoxication may contribute to the hyperlipemic effect of ethanol.     

Purification and characterization of lipoprotein lipase from pig myocardium.

1. Lipoprotein lipase was purified from pig myocardium by a two-step purification procedure involving (a) the formation of an enzyme-substrate complex and (b) affinity chromatography on Sepharose which contained covalently linked heparin. The purified enzyme gave in sodium dodecyl sulphate-polyacrylamide-gel electrophoresis one main band with an apparent molecular weight of 73 000. The enzyme, which was purified 70 000-fold, had a specific activity of 860 mumol of unesterified fatty acid liberated/h per mg of protein. 2. The purified enzyme hydrolysed [14C]triolein emulsions in the absence of added cofactors but its activity was increased fivefold by adding normal human serum. Of the low-density lipoprotein apoproteins only apolipoprotein CII could be substituted for serum in activating the enzyme. This lipase had maximum activity at 0.05-0.15 M-NaCl. Heparin increased the activity of the purified enzyme twofold at low concentrations, but high concentrations inhibited. The triglyceride lipase of pig myocardium thus resembles lipoprotein lipase purified from adipose tissue and from plasma, but is clearly different from pig hepatic triglyceride lipase.     

Chromosomes and reproductive behaviour of Finnish Taraxacum agamospecies

Material consisting of 157 accessions of 69 Finnish Taraxacum agamospecies, representing 7 sections, was grown in an experimental field for comparison of certain botanical and nutritional characteristics. This paper gives the collecting data as well as cytological and reproductive characteristics of the material. The largest section Taraxacum (Vulgariu ) was represented by 60 agamospecies, 59 of them triploid (2n = 24) and one tetraploid (T. penicilliforme , 2n = 32). The tetraploid and 37 triploids were chromosome counted for the first time. The diploid sexual species T. obtusilobum from Sweden was included for comparison. Other sections consisted of 3 triploids and 6 tetraploids, 3 tetraploid species of the section Erythrosperma being chromosome counted for the first time. Seedlings with deviating numbers were occasionally found. A banding technique of the chromosomes was developed but it did not allow the exact identification of other than the satellite chromosomes. Species-specific features were found in the flowering phenology and in several pollen characteristics (stainability, mean and variability of the size). There were indications of genetic variation within certain agamospecies in pollen characteristics. Isolated and emasculated (mostly only isolated) flower heads gave mostly a full seed set, which indicates obligate, autonomous agamospermy. Lower seed sets of T. adami, T. dahlstedtii and T. hamatiforme in isolation may be a sign of facultative apomixis in these species, requiring further study.     

Cleavage of the Phosphodiester Bond of Uridylyl-(3′,5′)-8-Carboxymethylaminoadenosine by Hydronium,Hydroxide and Zinc(Ii) Ions: A Model Study Aimed at Elucidating the Potential of a Carboxylate Function as an Intramolecular Catalyst

Abstract

Uridylyl-(3′,5′)-8-carboxymethylaminoadenosine has been synthesised, and its transesterification to uridine 2′,3′-cyclic phosphate in the presence and absence of Zn²⁺ ion has been studied. The results show that a carboxylate function in the vicinity of the phosphodiester bond accelerates the metal ion promoted cleavage but not the metal ion independent reaction. Under acidic conditions, the predominant reaction is the cleavage of the side chain, giving the 8-amino derivative.