Genetic differentiation in Sargassum polyceratium (Fucales: Phaeophyceae) around the island of Curaçao (Netherlands Antilles)

The seaweed Sargassum polyceratium Montagne inhabits a broad spectrum of subtidal and intertidal habitats. Genetic diversity and spatial genetic structure were examined within and among 12 stands using random amplified polymorphic DNA (RAPD) phenotypes. Data were analyzed using analysis of molecular variance (AMOVA) and Shannon's information measure. In both analyses, 60-75% of the variation occurred within stands and 25-40% between stands. These values are consistent with out-crossing, high-dispersal species. Significant differentiation was found among bays ca. 25 km apart (Shannon's G'_st averaged 0.37 and pairwise AMOVA K_st values averaged 0.272) and among stands 150-200 m apart within bays (AMOVA K_st values averaged 0.149). Effects of shore (windward vs. leeward), depth, and bay on population structure were tested. These analyses revealed that the factor depth is confounded with shore, and that bays show significant differentiation from each other but are not completely isolated from one another. Mantel tests for differentiation-by-distance were significant along both sides of the island but stronger along the windward side. A neighbor-joining analysis of genetic distances among stands showed that the effects of currents around both tips of the island were especially important for shallow populations. For S. polyceratium, depth and bay promote population differentiation along shores, yet dispersal around the tips of the island simultaneously connects these populations to varying degrees. This study highlights the importance of investigating the relative contribution of habitat factorsin relation to island-scale population structure.     

How mothers parent their children with behavior disorders: implications for unintentional injury risk

INTRODUCTION: This study was designed to test the role of parental supervision in explaining why children with behavior disorders have increased risk of unintentional injury. METHOD: Children referred to a pediatric behavior disorders clinic and their mothers were unknowingly observed in a "hazard room" environment that housed several items that appeared dangerous but actually were altered to be safe. RESULTS: Mother and child behavior in the hazard room was correlated to parent-, teacher-, and observational-reports of children's externalizing behavior patterns, children's injury history, and mother's parenting styles. Maternal ignoring of children's dangerous behavior in the hazard room was the strongest correlate to children's injury history. CONCLUSIONS: Poor parental supervision might serve as a mechanism to explain why children with behavior disorders, and those with oppositional behavior patterns in particular, have increased risk of unintentional injury.     

Characterization of the humic material formed by composting of domestic and industrial biowastes Part 1. HPLC of the cupric oxide oxidation products from humic acids

The changes induced by humification of anaerobically digested sewage sludge, source separated biowaste, and pulp mill biosludge were determined by extracting the fractions of bitumen and humic and fulvic acids from the samples of fresh and humified composts. In all cases, a distinct decrease in the amount of bitumen could be detected during humification. The amount of humic acids increased in sewage sludge and biowaste samples, but decreased in pulp mill biosludge sample during humification. The humic acids were degraded by CuO oxidation and the phenolic degradation products were analysed by reversed-phase high-performance liquid chromatography. The yield of these aromatic degradation products was in the range 0.9–2.0 % for each sample. The main phenolic degradation products were 4-hydroxybenzoic acid, vanillic acid, 4-hydroxybenzaldehyde, vanillin, syringaldehyde, and acetovanillone. Two lignin dimers, dehydrodivanillin and dehydrodiacetovanillone, were also identified.     

Experimental variability in characterization of cyfluthrin sorption to soil

To assess the risk of a pesticide to leach to groundwater or to run off to surface water after application, it is necessary to characterize the sorption of the pesticide to soil. For pyrethroids, their hydrophobicity, strong sorption to various materials, and low solubility make it difficult to accurately characterize sorption processes. The objective of this research was to evaluate the variability in cyfluthrin ((RS)-alpha -cyano-4-fluoro-3-phenoxybenzyl (1RS,3RS;1RS,3SR)-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylate) sorption to soil as affected by experiment conditions. To minimize cyfluthrin sorption on the walls of glass, silanized-glass, stainless steel, and PTFE centrifuge tubes, cyfluthrin solution was added to aqueous soil slurries or directly to soil, after which it was equilibrated with aqueous solution. Depending on the soil, variation in sorption coefficients, Koc, obtained using different experimental methodologies with one soil can be comparable to the variation in Koc values obtained for soils with different physical and chemical properties using one method. Koc values for cyfluthrin ranged from 56,000 to 300,000 L kg-1. Sorption methodology needs to be evaluated before sorption coefficients are used in predictive transport models.     

N2 fixation (nitrogenase activity) attributable to a specific Prochloron (Prochlorophyta)-ascidian association in Palau,Micronesia

Light-mediated nitrogenase activity (NA) consistently occurred in one of four species of tropical marine ascidians (sea squirts) hosting the symbiotic alga Prochloron (prochlorophyta) among reef habitats located in Palau, Micronesia. NA was limited to intact colonies of Lissoclinum patella exclusively colonized by cells of Prochloron. Neither isolated viable cells of Prochloron nor ascidians free of Prochloron revealed NA, indicating a strong dependence on the intact symbiosis for creating conditions conductive to N₂ fixation. The confinement of NA to L. patella may be related to both the oligotrophic habitat and the large colony size of this protochordate species. This is the first report of NA attributable to symbiotic alga residing in either an aquatic or a terrestrial animal.     

Annual occurrence,abundance and diversity of fish in a South Carolina intertidal creek

An intertidal creek in North Inlet Estuary, South Carolina, USA, was sampled monthly for 1 year to determine the occurrence, abundance and diversity of fish species. Sampling was so conducted as to reduce sampling bias to a minimum and all individuals caught were weighed and measured. A total of 16,611 individuals weighing 202.45 kg and comprising 51 species and 25 families of fish was collected. Three diversity indices were calculated for species number. Analysis of variance revealed that season had a highly significant effect on all indices and the number of species, but had no effect on the number of individuals caught.This work was supported by the Belle W. Baruch Foundation and the South Carolina State Development Board, and is Contribution No. 71 of the Belle W. Baruch Institute for Marine Biology and Coastal Research.     

Modulation of hepatic and intestinal glutathione S-transferases and other antioxidant enzymes by dietary lipids in streptozotocin diabetic rats

Antioxidant enzymes in liver and small intestine were investigated using control and streptozotocin diabetic rats fed diets with 5% olive, sunflower or fish oil for five weeks. In liver, Glutathione Peroxidase and Superoxide Dismutase decreased and in intestine Glutathione-S-transferase (GST) increased by diabetes. In isolated jejunum and ileum, this increase in GST activity was due to an increase in GST-alpha and -mu isoenzymes in jejunum and GST-alpha, mu and -pi in ileum. Since GST plays an important role in protecting tissues from oxidative damage, our results highlight the role of the intestine against free radicals in physiological or pathological situations.     

Foliar response of black cherry (Prunus serotina) clones to ambient ozone exposure in central Pennsylvania

During late summer of 1996 and 1997 we examined ozone-induced foliar injury in a plantation of 111 black cherry trees (ramets) comprising 15 clones originating from wild ortets growing in the Allegheny National Forest, Pennsylvania, and the Monongahela National Forest, West Virginia. The experimental plantation was a clonal seed orchard in Centre County, Pennsylvania, started in 1971 using ortet buds grafted onto seedling rootstocks of mixed origin. Clones differed significantly in severity of foliar injury symptoms (F=31.83, p<0.001). One clone (R-12) had significantly more foliar injury with >50% leaf area affected than other clones during both years. In contrast, clone R-14, which is from the same area in northcentral Pennsylvania as R-12, exhibited significantly less injury (LAA<6%). Although ambient O(3) concentrations were similar in both years, foliar injury was significantly greater (15.7%) in 1996 than in 1997 (9.9%). This is probably explained by lower stomatal conductance in 1997 caused by drier and hotter weather patterns in June and July of that year. Despite very different weather patterns and overall levels of injury in 1996 and 1997, mean clonal injury was significantly correlated between both years of assessment (r=0.92, p<0.001). Within tree crowns, foliage in lower and inner crown positions was significantly more injured than foliage in upper and exterior crown positions. There was no evidence of geographically based population differences in sensitivity to foliar O(3) injury. On the contrary, results demonstrate that wild genotypes of proximal geographic origin may differ greatly in sensitivity.     

PM2.5 chemical source profiles for vehicle exhaust, vegetative burning, geological material, and coal burning in Northwestern Colorado during 1995

PM_2.5 (particles with aerodynamic diameters less than 2.5 μm) chemical source profiles applicable to speciated emissions inventories and receptor model source apportionment are reported for geological material, motor vehicle exhaust, residential coal (RCC) and wood combustion (RWC), forest fires, geothermal hot springs; and coal-fired power generation units from northwestern Colorado during 1995. Fuels and combustion conditions are similar to those of other communities of the inland western US. Coal-fired power station profiles differed substantially between different units using similar coals, with the major difference being lack of selenium in emissions from the only unit that was equipped with a dry limestone sulfur dioxide (SO₂) scrubber. SO₂ abundances relative to fine particle mass emissions in power plant emissions were seven to nine times higher than hydrogen sulfide (H₂S) abundances from geothermal springs, and one to two orders of magnitude higher than SO₂ abundances in RCC emissions, implying that the SO₂ abundance is an important marker for primary particle contributions of non-aged coal-fired power station contributions. The sum of organic and elemental carbon ranged from 1% to 10% of fine particle mass in coal-fired power plant emissions, from 5% to 10% in geological material, >50% in forest fire emissions, >60% in RWC emissions, and >95% in RCC and vehicle exhaust emissions. Water-soluble potassium (K⁺) was most abundant in vegetative burning profiles. K⁺/K ratios ranged from 0.1 in geological material profiles to 0.9 in vegetative burning emissions, confirming previous observations that soluble potassium is a good marker for vegetative burning.