Transport and adsorption of antibiotics by marine sediments in a dynamic environment

Background, aim, and scope  Bed sediments are the major sink for many contaminants in aquatic environments. With increasing knowledge of and research on the environmental occurrence of antibiotics, there has been growing interest in their behaviour and fate in aquatic environments. However, there is little information about the behaviour of antibiotics in a dynamic water/sediment environment, such as river and coastal marine water. Therefore, the aims of the present study were: (1) to study the transport and distribution of four common antibiotics between water and sediment in both dynamic and quiescent water/sediment systems and (2) to understand the persistence and possible degradation of the four antibiotics in the two different systems. Materials and methods  A lid-driven elongated annular flume, designed to reduce the centrifugal effect, was used to simulate a dynamic water environment. In addition, a quiescent water/sediment experiment was conducted for comparison with the dynamic water system. The seawater and sediment, used in both experiments of flowing and quiescent water/sediment systems, were collected from Victoria Harbour, a dynamic coastal environment in an urban setting. The four antibiotics selected in this study were ofloxacin (OFL), roxithromycin (RTM), erythromycin (ETM), and sulfamethoxazole (SMZ), the most commonly used antibiotics in South China. Results and discussion  Antibiotics in an overlying solution decreased very quickly in the flume system due to the sorption to suspended particles and surface sediment. There were significant differences in the adsorption of the four antibiotics in sediment. OFL showed a high tendency to be adsorbed by sediment with a high K _d value (2980 L/Kg), while the low K _d values of SMZ indicated that there was a large quantity in water. The four antibiotics reached a depth of 20–30 mm in the sediment over a period of 60 days in the flume system. However, the compounds were only found in surface sediment (above 10 mm) in the quiescent system, indicating the influence of the dynamic flume system on the distribution of antibiotics in sediment. OFL showed a moderate persistence in the dynamic flume system, while other three antibiotics had less persistence in sediment. However, all of the four compounds showed moderate persistence in the quiescent system. Recommendations and perspectives  The study showed the rapid diffusive transfer of antibiotics from water to sediment in the dynamic flume system. The four antibiotics exhibited larger differences in their adsorption to sediment in both dynamic and quiescent systems due to their different K _d values. The high sorption of antibiotics to marine sediment may reduce their availability to benthic invertebrates.     

Chemical Characterization of Testes Meals Made from Alaska's Seafood Processing Byproducts

ABSTRACT

Our objective was to produce a unique feed ingredient from underutilized walleye pollock (Theragra chalcogramma) and pink salmon (Oncorhynchus gorbuscha) testes. Protein content in meals from both species (72% and 80%, respectively) were above the values found in high quality herring meals (～70%), but both were poor in some essential amino acids, e.g., methionine. Additionally, both were good sources of the amino acid taurine (1.7 and 2.2% of meal, respectively). Pollock meal was very rich in phospholipids (82% of total lipids) and in DHA (28 mg/g meal) and EPA (18 mg/g meal), indicating potential as an ingredient in larval starter diets. The purine contents in both pollock and salmon testes meals were more than 10 times the concentrations found in other fish byproducts or commercial fishmeals. The high concentrations of purines found in these testes, especially in the salmon meal, make it an ideal candidate for an immune system stimulant when added to dietary formulations.     

Study of oat globulin conformation by Fourier transform infrared spectroscopy.

The conformation of oat globulin dispersions (10% in D2O) under the influence of pH, chaotropic salts, protein structure perturbants, and heating conditions was studied by Fourier transform infrared (FTIR) spectroscopy. The FTIR spectrum of oat globulin showed major bands from 1670 to 1634 cm(-1), corresponding to the four major types of secondary structures, that is, beta-turns, beta-sheets, alpha-helices, and random coils. At extreme acidic and alkaline pH conditions, there were changes in intensity in the bands attributed to beta-sheet structures (1626, 1634, and 1682 cm(-1)), and shifts of the bands to higher or lower wavenumbers, indicating changes in conformation. In the presence of some chaotropic salts, the 1626 and 1634 cm(-1) bands were shifted upward, with a marked decrease in the intensity of the 1634 cm(-1) peak. The addition of several protein structure perturbants led to a slight shift in the alpha-helix/random coil bands and a marked reduction in the beta-sheet peaks, suggesting protein unfolding. Heating under aggregating conditions led to slight shifts in all of the major bands and progressive changes in the intensity of the alpha-helix, beta-sheet, and beta-turn peaks, suggesting protein denaturation. This was accompanied by marked increases in intensity of the two intermolecular beta-sheet bands (1682 and 1624-1626 cm(-1)) associated with the formation of aggregated strands. The IR spectra of soluble and insoluble aggregates showed a redistribution of native and extensively denatured proteins in the two fractions.     

Content and composition of essential oil and content of rosmarinic acid in lemon balm and balm genotypes (<Emphasis Type="Italic">Melissa officinalis</Emphasis>)

Lemon balm (Melissa officinalis L.) is used since ancient times because of its sedative, spasmolytic and antiviral effects. Its therapeutic impact is due to the content of essential oil and rosmarinic acid. A set of 68 M. officinalis genotypes was evaluated for content and composition of essential oil and the content of rosmarinic acid. For all genotypes the level of ploidy was determined. The 68 genotypes were clone plants grown and evaluated for two years at Quedlinburg. For analysis of secondary metabolites distillation, gas chromatography and high performance liquid chromatography was used. The content of essential oil varied in this study in ranges from 0.03 to 0.33% for the second cut 2010 and 0.01–0.35% for the second cut 2011. The rosmarinic acid content ranged in the year 2010 from 3.67 to 7.55% and in the year 2011 from 4.92 to 8.07%. Via statistical analyses two chemotypes of essential oil were found: chemotype citral and chemotype β-caryophyllene oxide. Ploidy was determined for all genotypes and two cytotypes were found: diploid 2n = 2x = 32 (62 of 68 genotypes) and triploid 2n = 3x = 48 (6 of 68 genotypes).     

The effects of biocidal treatments on metabolism in soil—III. The relationship between soil biovolume,measured by optical microscopy,and the flush of decomposition caused by fumigation

The hypothesis that the flush of decomposition following fumigation is a measure of the amount of biomass in a soil was tested by comparing the biomass thus found, and as calculated from direct microscopic measurement of the soil biovolume. Eight soils developed under contrasting systems of management and climate were used, six from England and two from Nigeria. The biovolume was measured by a modification of the Jones and Mollison procedure, in which agar films prepared from known amounts of soil were stained with phenolic aniline blue. Fluorescent stains were less satisfactory in that they did not stain as wide a range of organisms as phenolic aniline blue. Spherical organisms were divided into 13 size classes, with diameters ranging from 0·3 to 19 μm, and the numbers in each size class counted. Hyphae were divided into seven diameter classes, with dia. ranging from 1 to 11 μm, and the lengths in each class measured. For seven of the soils there was close agreement between the two different methods of measuring biomass C. With an acid woodland soil (pH 3·9). the biomass C, as calculated by direct microscopy, was seven times that calculated from the size of the flush; it is suggested that this discrepancy arose because stainable cell walls from dead organisms persist for much longer in the strongly acid soil than in the other, more nearly neutral, soils.Both methods were used to follow the effects of fumigation on the soil biomass. A near-neutral soil was fumigated with CHCl₃, the fumigant removed and the soil incubated for 53 days at 25° C. The decrease in biomass caused by fumigation was less as measured by direct microscopy than as measured from the size of the flush, suggesting that stainable cell walls of killed organisms can persist for a considerable time after fumigation.Data on the relationship between the size of soil organisms and their contribution to soil biovolume are presented graphically. The biovolume in hyphae and in ‘spherical’ organisms was roughly equal in all soils. There was a linear relationship between the cumulative biovolume and the logarithm of organism volume lor ‘spherical’ organisms over the volume range 0·05 μm³ to 100 μm³. If, for a given soil, the volume range is divided into equal volume classes on a logarithmic basis, each class contains the same biovolume. Thus, comparing equal logarithmic volume classes, a class of rare large organisms contains as much biovolume as a class of numerous small organisms.     

Formation of Homopolymers and Heteropolymers Between Wheat Flour and Several Protein Sources by Transglutaminase‐Catalyzed Cross‐Linking

The effect of different protein sources (soy flour, lupin flour, egg albumin, gelatin powder, protein‐rich beer yeast flour) on wheat dough functionality was tested by determining gluten index, texture properties, and thermomechanical parameters. Transglutaminase (TG) was also added to improve the dough functionality by forming cross‐links. The presence of protein sources had a significant effect on the gluten index, with the exception of lupin flour. Gelatin and the presence of TG resulted in significant single effects on the texture properties of the wheat‐protein dough. All the protein sources significantly modified the mixing characteristics of the dough or the thermal behavior. Capillary electrophoresis studies of the water‐soluble, salt‐soluble, and glutenin proteins indicated that interactions were mainly within proteins, thus homologous polymers. Scanning electron microscopy studies of the doughs made from blends of wheat and protein sources doughs supported the formation of heterologous structures in the wheat‐lupin blends. The combination of TG and lupin would be a promising method to be used on the treatment of insect‐damaged or weak flours, to increase the gluten strength.     

Fate of Zinc Ammonia Acetate in Soils and Its Uptake by Corn

Zinc ammonium acetate (ZAA) is applied to soil with anhydrous ammonia as a carrier to improve corn (Zea mays L.) productivity. To study the fate of ZAA in the soils, a laboratory leaching experiment was conducted with ¹⁴C-ZAA and ⁶⁵Zn-ZAA using water or NH₄OH as carrier. Results showed that ZAA degraded in the soil and released CO₂. The released CO₂ was from the acetate component of ZAA and accounted for less than 0.06% of the total applied ¹⁴C. Using H₂O as carrier resulted in more CO₂ release than using NH₄OH, regardless of soil type. However, more ¹⁴C was detected in the leachate when using NH₄OH as a carrier than when using H₂O. A plant uptake experiment using ¹⁴C-ZAA and ⁶⁵Zn-ZAA indicated that four-leaf-stage corn seedlings absorbed higher amounts of ¹⁴C in the stem and root than in the leaves. The ⁶⁵Zn was detected in most tested plant parts. Our study showed that ZAA enhanced cytokinin levels in root and/or shoot tissues of corn seedlings, suggesting a secondary regulatory effect of ZAA in improving corn productivity.     

Effect of Foliar Application of Phosphorus on Winter Wheat Grain Yield,Phosphorus Uptake,and Use Efficiency

ABSTRACT

One would expect foliar applied phosphorus (P) to have higher use efficiencies than when applied to the soil, but limited information is available concerning this. Experiments were conducted in 2002, 2003, and 2004 to determine the effect of foliar applications of P on winter wheat grain yields, P uptake, and use efficiency. Twelve treatments containing varying foliar P rates (0, 1, 2, and 4 kg ha^{? 1} in 2002 and 2003 and additional 8, 12, 16, and 20 kg ha^{? 1} in 2004) with and without pre-plant rates of 30 kg ha^{? 1} were evaluated. Foliar applications of P at Feekes 7 generally increased grain yields and P uptake versus no foliar P. Use efficiency was higher when P was applied at Feekes 10.54. Results from this study suggested that low rates of foliar applied P might correct mid-season P deficiency in winter wheat, and that might result in higher P use efficiencies.     

Dry matter and primary nutrient accumulation in soybeans as affected by combined Nitrogen levels

Nodulating and non‐nodulating soybeans were grown on a Alfic Udipsamment and a Typic Hapludoll amended with 10 or 100 kg N/ha. Tissue and grain samples were analyzed to determine N₂‐fixation, dry matter, and N, P, and K accumulation. Highest grain yields were associated with the highest levels of N₂‐fixation and N and K accumulation in grain. The largest dry matter production was by nodulating plants grown on a high soil N regime. Nodulating plants accumulated more grain and tissue N, P, and K than non‐nodulating plants. Nitrogen stress increased P concentrations in both grain and tissue and decreased harvest indices.