Characterization of Thermal Traits of Starches from Argentinian Maize Inbreds: Genotypic and Crop Year Variability

Thermal properties are among the most important end‐use characteristics of starch from maize (Zea mays L.). Knowledge of the contribution of genotype and environment to the total variance for starch thermal properties is needed to aid in defining a testing strategy for selecting maize with desirable thermal starch properties. Thus, the objectives of this study were 1) to characterize the thermal properties of starches from a group of recently developed Argentine maize inbred lines, and 2) to assess the variability in starch properties attributable to genetic and crop year effects. Twelve inbred lines developed by the National Institute of Agricultural Technology (INTA) in Argentina derived from a wide array of germplasm sources were evaluated. Gelatinization and retrogradation properties were measured by differential scanning calorimetry. Enthalpy means for gelatinization were below means reported in the literature, suggesting possible energy savings when using these starches. The ratio between change in enthalpy for retrogradation and gelatinization was above the mean reported in the literature, suggesting a starch that may be useful as a dietary fiber. Significant environmental effects caused by crop year were detected. Some inbred lines, with smaller observed ranges and standard deviations across environments, may be more stable for some properties.     

Molecular Weight Distribution of (1→3)(1→4)-β-Glucan Affects Pasting Properties of Flour from Oat Lines with High and Typical Amounts of β-Glucan

Experimental (N979-5-2-4 and IA95111) and traditional oat lines (Jim and Paul) with average %β-glucan of 7.5, 7.8, 4.9, and 4.4%, respectively, were grown in 2002, 2003, and 2004. Molecular weight (MW) distributions of the β-glucans were examined for potential variations among growing years and for relationships with pasting properties measured by Rapid ViscoAnalyser under three separate conditions: 1) in silver nitrate (SN) solution to inactivate enzymes; 2) hydrolyzed by α-amylase to eliminate the effect of starch; and 3) treated with lichenase to remove β-glucan. The β-glucan was extracted by a process involving multiple precipitation and dialysis steps, and the MW distributions were determined by HPLC. %β-Glucan in N979-5-2-4 and IA95111 lines were consistently and significantly greater (P < 0.05) than in Jim and Paul lines during three growing years. The contribution of β-glucan to peak viscosity on the RVA was substantially greater than that of the starch for all three years. The molecular number average and peak MW of β-glucan from N979-5-2-4 and IA95111 were greater than these values for Jim and Paul, and values were consistent among years. The MW of extracted β-glucan was associated with pasting properties after amylase hydrolysis, but not after treatment with lichenase or in SN solution.     

Gelatinization and Retrogradation Traits of Starches from Argentinian Maize Inbred Lines: Patterns of Correlation Among Traits

Efforts are being made to identify sources of starches with unique end-use properties, such as thermal properties, within a wide array of maize germplasm. Because redundancy may exist when evaluating these traits, it would be useful to know the pattern of correlation among traits involved to focus the expensive stage of evaluation of germplasm on traits that do not provide redundant information. The objectives of this study were to analyze the pattern of correlations between starch gelatinization and retrogradation-associated traits in a group of 12 Argentine maize inbred lines and to develop predictive models among traits when possible. Traits measured by differential scanning calorimetry included gelatinization and retrogradation properties. Pearson correlation coefficients among starch thermal properties were determined from univariate analyses, and canonical correlations were determined from multivariate analyses. Canonical correlation analyses were more sensitive in detecting associations between starch gelatinization and retrogradation parameters than univariate analyses. Multiple regression equations to estimate the change in enthalpy of starch gelatinization and retrogradation traits, especially for change in enthalpy and percentage of retrogradation, were obtained and validated with an independent data set.     

The effects of scion maturation on growth and reproduction of grafted slash pine

Establishment of the University of Florida Cooperative Forest Genetics Research Program's clone banks provided an opportunity to look at scion maturation effects on growth and reproduction of many grafted slash pine clones. In 1988 and 1989, clone banks were established in nine locations in the Southeastern United States. Over 460 scion clones varying from 5 to greater than 40 years old from time of seed germination (chronological age) were grafted into the clone banks. Comparisons of diameter growth, height growth, lateral branch number and female and male strobili production were made annually for six years after grafting.Within slash pine clone banks, there were significant effects due to scion chronological age. Chronologically older scions (backward selections) grew less, had fewer branches and produced only a few more female strobili than chronologically younger material (forward selections). Forward selections produced significantly more catkin clusters than backward selections. By year six, there was no significant difference in numbers of female strobili per tree between backward and forward scions, but forward selections produced about 2.5 times as many catkin clusters as the backward selections. Similar effects on growth and reproduction due to chronological age were also found among clones within the forward selections, with older selections growing more slowly and producing fewer catkin clusters. The size and breadth of this study lends strong support to the idea that these patterns of growth will occur for grafted slash pine in any location throughout its native range.     

Synchronous climate changes in antarctica and the north atlantic

Central Greenland ice cores provide evidence of abrupt changes in climate over the past 100,000 years. Many of these changes have also been identified in sedimentary and geochemical signatures in deep-sea sediment cores from the North Atlantic, confirming the link between millennial-scale climate variability and ocean thermohaline circulation. It is shown here that two of the most prominent North Atlantic events-the rapid warming that marks the end of the last glacial period and the Bolling/Allerod-Younger Dryas oscillation-are also recorded in an ice core from Taylor Dome, in the western Ross Sea sector of Antarctica. This result contrasts with evidence from ice cores in other regions of Antarctica, which show an asynchronous response between the Northern and Southern Hemispheres.     

Use of acoustics to enhance the efficiency of physical screens designed to protect downstream moving European eel (Anguilla anguilla)

European eel, Anguilla anguilla (L.), is vulnerable to entrainment at a variety of man‐made intakes, including those that lead to hydropower turbines or other abstraction points. Two experiments were conducted to investigate the potential for acoustic stimuli to improve the efficiency of a vertical bar screen to guide downstream moving eel. Three underwater speakers were installed along the channel wall of an external flume, upstream of the screen. In the first experiment (a), screen guidance efficiency recorded in the presence (treatment) and absence (control) of a continuous broadband stimulus was individually compared between fish from two respective groups. Adopting a “before‐after” design, the second experiment (b) assessed individually the guidance of control eels from the group previously used in experiment 1 when exposed to a 100 Hz pulse. The majority of eels reached the bypass in both experiments with only three passing through the screen during the controls against one during each acoustic treatment. Rejection of the area adjacent to the speakers was more common during the acoustic treatment, with eels moving past the speakers more rapidly in the presence of sound. The results suggest that employing acoustic stimuli enhances the guidance efficiency of physical screens.     

The relationship between anthropogenic light and noise in U.S. national parks

Landscape Ecology - Natural sound and light regulate fundamental biological processes and are central to visitor experience in protected areas. As such, anthropogenic light and noise have negative...     

Volatile and water-soluble inhibitors of nitrogen mineralization and nitrification in a ponderosa pine ecosystem

Summary Bioassay experiments were performed to test for inhibition of the processes of nitrogen mineralization and nitrification by organics in the forest floor of a ponderosa pine ecosystem. Water-extractable organics in the forest floor were tested by applying filtered extracts to the assay soil. The extract decreased nitrate production by 17.0% and decreased net mineralization by 4.1%. Inhibition by volatile organics was tested by placing vials containing forest floor or selected terpenoids of ponderosa pine in sealed jars containing the assay soil. Nitrate production was inhibited by 87.4% and 100%, and net nitrogen mineralization was inhibited by 73.3% and 67.7% in the jars with forest floor and terpenoids, respectively. Organics which are partially water-soluble and are volatile (such as terpenoids) would be very effective inhibitors of nitrogen cycling processes.     

Determination of the diglycidyl ether of bisphenol A and its derivatives in canned foods.

Migration of the diglycidyl ether of bisphenol A (DGEBA) to food from can enamels and can pull-top seals is reported. Derivatives of DGEBA are also determined in some foods. Levels of DGEBA in the foods surveyed in this study range from nondetected (<0.3 ppb) to 50 mg/kg as determined by liquid-liquid extraction or solid-phase extraction coupled with high-pressure liquid chromatography using fluorescence detection. Confirmation of the analytes is by gas and/or liquid chromatography with mass spectral analysis. Fourier transform infrared spectroscopy with 30 degrees specular reflectance/transmittance is used to characterize the coated food contact surfaces. Stability studies with DGEBA in water, acid, and saline solutions show conversion to the hydrolysis products and chloro adducts occurs readily. The presence of DGEBA derivatives in food demonstrates that analysis for DGEBA migration alone is not a good indicator of total migration from can coatings to foods.     

The use of peepers to sample pore water in acid sulphate soils

Serious environmental impacts of acidic drainage from acid sulphate soils in coastal areas are the result of the interactions between the hydrologic cycle, land use and drainage management, and pore water chemistry. In this study, in situ , diffusion-controlled dialysis profile samplers, or peepers, were used to examine pore water chemistry of acid sulphate soils in a coastal, sugarcane-producing area in Eastern Australia. The peepers sampled pore water at 20-mm intervals over a 1.0-m length, permitting excellent resolution of the sharp transitions in pore water chemistry that occur around a soil profile's iron sulphide oxidation front. Comparison of peeper profiles with soil water profiles extracted from soil samples by centrifuging, illustrated the advantages of peepers over conventional soil water sampling techniques in unconsolidated, sulphidic soils. For conventional sampling, the low permeability, gel-like, unoxidized soil samples had to be frozen then thawed before water could be extracted by centrifuging. Peeper profiles of species not involved in redox reactions agreed well with those from centrifuged soil extracts. Redox sensitive species, however, were in poorer agreement because of the lengthy soil sample preparation and extraction procedures required for extraction by centrifuging. The approximately 6-day equilibration time required for peeper sampling allows them to follow monthly or seasonal changes in pore water chemistry in acid sulphate soils due to variations in climate, and land use and management.