bluuebunny/crossref_metadata_2025 huggingface dataset:
Development and application of microsatellites in plant breeding
Authors: Gonçalves-Vidigal Maria Celeste , Rubiano Luciana Benchimol
Published: September 2012

Molecular markers are powerful tools for analyzing genome diversity within a species, and to evaluate genetic relationships between individuals and populations. Among them, microsatellites (SSRs) are one of the most important polymorphic markers that can be used effectively to distinguish germplasm accessions. These markers present high informative content due to their codominant inheritance, multiallelism, mendelian pattern and good genome coverage. The enrichment methodology for microsatellite development has a superior efficiency in plants, especially when performed using biotin-labeled microsatellite oligoprobes and streptavidin-coated magnetic beads. The development of EST-SSR markers has become a fast and relatively inexpensive way but it is limited to species for which this type of database exists. Given the high polymorphism level of microsatellites when compared to other markers, SSRs have been used to study population structure, for genetic diversity analysis, genetic mapping and marker assisted selection.
Genetic improvement of vegetables: development of open-pollinated cultivars
Authors: Melo Paulo César Tavares de
Published: September 2012

The estimated market value for vegetable seeds in Brazil, based on prices paid by producers, reached around R$ 300 million in 2007. Seeds from open-pollinated cultivars accounted for only 18 %. This data clearly indicates the changeover from open-pollinated to hybrid seeds in recent decades in the main varietal segments of the Brazilian vegetable market. This lecture will outline a historical retrospective of the pioneer activities of genetic improvement of vegetable crops targeting open-pollinated cultivars in breeding programs conducted by the public universities and research institutes and their impact on the development of the Brazilian horticulture. The current situation, challenges and future prospects will also be discussed.
Integrating Cotton and Beef Production in the Texas Southern High Plains: I. Water Use and Measures of Productivity
Authors: Allen V. G. , Brown C. P. , Kellison R. , Green P. , Zilverberg C. J. , Johnson P. , Weinheimer J. , Wheeler T. , Segarra E. , Acosta‐Martinez V. , Zobeck T. M. , Conkwright J. C.
Published: September 2012

Texas High Plains agriculture, largely dependent on water from the Ogallala aquifer for irrigation, exemplifies semiarid agricultural regions where irrigation is used at nonsustainable rates of extraction. Integrating crop and livestock systems has been suggested to conserve water and to achieve other environmental and economic goals compared with monoculture systems. From 1998 to 2008, two large‐scale systems, with three blocks in a randomized block design, compared irrigation water, productivity, chemical inputs, and specific pests of (i) a cotton (Gossypium hirsutumL.) monoculture, and (ii) an integrated three‐paddock system that included cotton in a two‐paddock rotation with grazed wheat (Triticum aestivumL.) and rye (Secale cerealeL.) and the perennial variety WW‐B. Dahl old world bluestem (OWB) [Bothriochloa bladhii(Retz) S.T. Blake] in a third paddock for grazing and seed production. All paddocks were irrigated by subsurface drip. Angus crossbred beef steers (Bos taurus; initial BW 229 kg; SD = 33 kg) grazed 185 d from January to mid‐July each year. During the 10 yr following the establishment year, cotton lint yield was similar and averaged 1370 kg ha−1for both systems. Bluestem seed yield averaged 25 kg pure live seed (PLS) ha−1. Steers gained 139 kg on pasture and 0.79 kg d−1. Per hectare, the integrated system used 25% less (P< 0.001) irrigation water, 36% less N fertilizer, and fewer other chemical inputs than monoculture cotton. Integrated production systems that are less dependent on irrigation and chemical inputs appear possible while achieving goals of sustainability, fiber production, and food security.
Fertilizer Value of Lime‐Stabilized Biosolids as a Soil Amendment
Authors: Guo M. , Song W. , Kazda R.
Published: September 2012

To promote and guide agricultural uses of lime‐stabilized biosolids (LSB), the fertilizer value of this particular organic waste was determined. Lime‐stabilized biosolids from a regional wastewater treatment plant were examined for total nutrient content, liming effectiveness, and nutrient release kinetics and supply capacity using chemical characterization, batch incubation, and column leaching techniques. The LSB contained 279 g kg−1 organic carbon, 40.3 g kg−1 N, 13.2 g kg−1 P, 1.8 g kg−1 K, 151 g kg−1 Ca, and 6.6 g kg−1 S, and its lime equivalency was 261 g CaCO3 kg−1. Incubation of the LSB with a sandy loam (pH 5.3; lime buffer capacity 350 g CaCO3 kg−1 per unit pH) at 4 and 12.5 g kg−1 for 90 d raised the soil pH to 6.3 and 7.1, respectively, indicating 56% of the LSB's CaCO3 equivalency was effective in neutralizing soil acids. Intermittent water leaching of 10 g kg−1 LSB‐amended soil columns resulted in sigmoidal release of 15.9 g N, 0.23 g P, 1.1 g K+, 42.0 g Ca2+, 10.7 g SO42–, and nearly 0 g toxic elements in the leachate per kg of the applied LSB in the leachate in 140 d. If applied at 10.4 t ha−1, the LSB would significantly reduce soil acidity and furnish 165 kg N, 2.4 kg P, and 11.4 kg K available to per hectare of seasonal crops.
Using Bimodal Lognormal Functions to Describe Soil Hydraulic Properties
Authors: Romano N. , Nasta P. , Severino G. , Hopmans J. W.
Published: September 2012

Accurate parameterization of the soil hydraulic properties represents a key issue for the modeling of soil water transport processes. The more complex the soil structure, the more crucial this requirement becomes. In dealing with this problem for structured and well‐aggregated soils, we have pursued the general objective of developing hydraulic relationships whose parameters characterize the soil's pore size distributions, thereby providing a physically based framework for the hydraulic relationships of bimodal soils. In our work, we assumed that the soil water retention function is determined by linear superposition of two distinct pore domains, which can be associated with textural and structural retention behaviors, respectively. The composite soil water retention function was described by Kosugi's lognormal function, with parameters being directly associated with the mean and variance of the soil pore size distribution for each pore domain. The two components of soil water retention were linked by a weighting factor to which a physical meaning can also be given. An important and practical advantage of the proposed bimodal water retention function is that a closed‐form analytical expression is obtained for the bimodal hydraulic conductivity function using pore size distribution parameters. This is relevant because we suggest that soil hydraulic properties can be characterized by the soil particle size distribution. Sensitivity analysis and comparisons with experimental data were used to evaluate the proposed bimodal lognormal hydraulic functions and to demonstrate their increased effectiveness in predicting the hydraulic conductivity characteristic of soils.
Clay Dispersion from Soil as a Function of Antecedent Water Potential
Authors: Dexter Anthony R. , Richard Guy , Czyz Ewa A. , Davy Joëlle , Hardy Michel , Duval Odile
Published: September 2012

Two standard tests for soil stability in water involve assessment of the readily dispersible clay (RDC) content of predried soil samples. It is shown that this predrying limits the applicability of the tests to very dry soils. Ways to avoid this limitation are developed. Undisturbed soil samples were collected from the 10‐ to 15‐cm depth of arable topsoils at Villamblain and Faux Perche and from the 0‐ to 5‐cm depth from plowed and direct‐drilled plots at Boigneville. These soils in north‐central France were collected from the field when moist (near field capacity). A range of water contents and corresponding pore water potentials (or suctions h) was produced by slow drying in air. For moist soils at field capacity (h = 100 hPa) the amount of RDC was large. Readily dispersible clay decreased progressively with increasing antecedent suction, h For soil samples dried to beyond h > 10 MPa, the RDC was reduced to small values. With such intensely dried soils, rewetting for up to 2 wk did not reverse the effect on RDC. At h = 4500 hPa, re‐equilibration to h = 100 hPa reversed the effect of this moderate drying on RDC. Two standard conditions (moist and dry) are proposed for measurement of clay dispersion from soil into water. The moist condition is relevant to soil at the end of a long, wet period (e.g., at the end of the winter in temperate climates), whereas the dry condition is relevant to dry surface crusts and dry topsoils. We conjecture that the soil “resets” during long, wet periods to values of stability and RDC at equilibrium with field capacity. Experimental procedures used to determine the content of RDC in moist and dry soils are described.
The Nanopore Inner Sphere Enhancement Effect on Cation Adsorption: Sodium, Potassium, and Calcium
Authors: Ferreira D. R. , Schulthess C. P.
Published: September 2012

Nanopores in minerals can have a significant impact on cation adsorption, known as the nanopore inner‐sphere enhancement (NISE) effect. Four zeolites representing three size classes of nanoporosity were used in this study to further elucidate the NISE phenomenon and describe its effects on the adsorption of Na, K, and Ca. Sodium and K ions have the same charge, but different ionic diameters. Sodium and Ca ions have similar ionic diameters, but different charges. Adsorption envelopes were created for these three cations on the four zeolites: zeolite Y, ZSM‐5, ferrierite, and mordenite. Comparisons of the magnitudes of the adsorption of Na, K, and Ca on the four zeolites indicated that all cations adsorbed weakly on zeolite Y (large nanopores), Na and K adsorbed strongly on ZSM‐5 and ferrierite (medium nanopores) while Ca adsorbed weakly, and all three cations adsorbed strongly on mordenite (small nanopores). It is noteworthy that in the medium nanopores, the two monovalent cations Na and K adsorbed more strongly than Ca, a divalent cation. The NISE effect is responsible for the changes in the relative strength of each cation's adsorption. This is an unusual adsorption mechanism and is counter to the traditional understanding of ion exchange reactions.
Nitrogen Mineralization in Riparian Soils along a River Continuum within a Multi‐Land‐Use Basin
Authors: Evans Daniel M. , Schoenholtz Stephen H. , Wigington Parker J. , Griffith Stephen M.
Published: September 2012

Nitrogen dynamics in riparian systems are often addressed within one land‐use type and are rarely studied on watershed scales across multiple land uses. This study tested for temporal trends and watershed‐wide spatial patterns in N mineralization and identified site factors related to N mineralization. We measured net N mineralization in situ at monthly intervals for 1 yr at 32 riparian sites along the 124‐km length of the Calapooia River, Oregon. We observed seasonal trends of mean net N mineralization with relatively low rates in the fall (29.8 kg N ha−1 yr−1) and winter (30.1 kg N ha−1 yr−1) and relatively high rates in the spring (122.1 kg N ha−1 yr−1) and summer (99.7 kg N ha−1 yr−1) when conditions for microbial activity and decomposition were likely enhanced. Annual net N mineralization on an area basis ranged from −13.5 to 234.0 kg N ha−1 yr−1 with a mean for all sites of 50.1 kg N ha−1 yr−1 Annual net N mineralization per kilogram of soil ranged from −16.2 to 207.1 mg N kg soil−1 yr−1, with a mean for all sites of 64.4 mg N kg soil−1 yr−1 Regression analysis revealed hardwood basal area and coverage of grass as significant positive predictors of kilograms of N mineralized per hectare. Location along the river explained 22% of the variability of N mineralization per hectare, indicating that riparian areas may function differently along the length of the river.
Soil Carbon and Phosphorus Pools in Field Crop Rotations in Pampean Soils of Argentina
Authors: Ciampitti Ignacio A. , García Fernando O. , Picone Liliana I. , Rubio Gerardo
Published: September 2012

In temperate cropping systems, a better understanding of soil C and P transformations is pertinent to evaluate crop management consequences in the medium term. Six‐year cropping systems experiments consisting of corn (Zea mays L.)–double‐cropped wheat (Triticum aestivum L.)/soybean [Glycine max (L.) Merr.] (two sites) and corn–soybean–double‐cropped wheat/soybean (two sites), with (Fp) or without P added (Wp), were evaluated in the Pampean soils of Argentina. The objectives were (i) to quantify the effects of continuous P fertilization on the size and vertical distribution of C and P in total organic C (TOC) and particulate organic matter (POM) fractions and (ii) to evaluate the POM‐P fraction as a potential indicator of crop P availability. Annually, an average P rate of 34 kg P ha−1 was applied in Fp plots. The TOC, total P (TP), POM‐C, and POM‐P were measured in the 0‐ to 5‐, 5‐ to 10‐, and 10‐ to 20‐cm soil depths at the end of the 6‐yr period. Phosphorus fertilization increased TOC from 0.5 to 2.5 g C kg−1 and TP from 24.1 to 77.4 mg P kg−1 in the 0‐ to 20‐cm depth. The POM‐C and POM‐P fractions were more sensitive than TOC or TP to P fertilization, increasing by 14 and 47%, respectively, in the 0‐ to 20‐cm depth under continuous P addition. The greatest differences in POM‐C and POM‐P among treatments occurred in the surface soil layer. A significant relationship was found between POM‐P and corn P uptake at anthesis.
Soil Water Content Distributions between Two Emitters of a Subsurface Drip Irrigation System
Authors: Kandelous Maziar M. , Šimůnek Jiří , van Genuchten M. Th. , Malek Keyvan
Published: September 2012

Subsurface drip irrigation (SDI) systems are increasingly being used in agriculture in attempts to use the available water more efficiently. The proper design and management of SDI systems requires knowledge of precise distribution of water around emitters. We conducted both field and numerical experiments to evaluate the soil water content distributions between two neighboring emitters when their wetting patterns started to overlap. The experiments involved SDI systems with emitters installed at different depths and with different spacings along the drip lateral. The HYDRUS software package was used to analyze the field data, assuming modeling approaches in which emitters were represented as (i) a point source in an axisymmetrical two‐dimensional domain, (ii) a line source in a planar two‐dimensional domain, or (iii) a point source in a fully three‐dimensional domain. Results indicated that SDI systems can be accurately described using an axisymmetrical two‐dimensional model only before wetting patterns start to overlap, and a planar two‐dimensional model only after full merging of the wetting fronts from neighboring emitters. A fully three‐dimensional model appears to be required for describing subsurface drip irrigation processes in their entirety.
Assessment of Lignin‐Related Compounds in Soils and Maize Roots by Alkaline Oxidations and Thioacidolysis
Authors: Machinet Gaylord Erwan , Bertrand Isabelle , Chabbert Brigitte
Published: September 2012

Lignin and hydroxycinnamic acids (p‐coumaric and ferulic acids), due to their specificity to vascular plants, can be used as indicators of the fate of plant‐derived organic matter in soils. Two chemical degradative methods allowing the recovery of total hydroxycinnamic acids and lignin monomers based on alkaline hydrolysis (THA method) and thioacidolysis, respectively, were compared with alkaline oxidation with CuO on soil and maize (Zea mays L.) roots of different genotypes. Thioacidolysis, commonly used in plant science, was applied for the first time to soil in this study and its sensitivity to different levels of organic carbon was assessed. Syringyl, vanillyl, and cinnamic acids (p‐coumaric and ferulic acids) as biomarkers of lignin‐derived compounds were determined in a long‐term soil incubation experiment with added roots of different maize genotypes. The recovery yields of lignin monomers were compared with the CuO oxidation, thioacidolysis, and THA methods. Thioacidolysis was successfully applied to soil amended with maize roots and was shown to better identifying the uncondensed lignin structures in soil, which are more susceptible to biodegradation than condensed structures.
Prefreeze Soil Moisture and Compaction Affect Water Erosion in Partially Melted Andisols
Authors: Nishimura Taku , Kamachi Noriyuki , Imoto Hiromi , Mizoguchi Masaru , Miyazaki Tsuyoshi
Published: September 2012

In this study, artificial rainfall was applied to a partially frozen Andisol soil, and the effects of the subsoil's physical conditions, prefreeze moisture condition, and soil compaction on surface runoff and soil loss were studied. The soil, an Andisol from a mountainous region of Japan, was packed into a plastic box to a thickness of 0.08 m to attain a predetermined moisture condition and dry bulk density, then stored in a freezer at −30°C overnight to create a sample representative of frozen subsoil. Twenty millimeters of unfrozen soil were added on top of the frozen subsoil to simulate a thawing surface layer. During the simulated rainfall (42 mm h−1) experiment, surface runoff, soil loss, and seepage from outlets at the front wall of the downslope end of the box were sampled periodically. In the early stage of rainfall, the impermeable frozen subsoil increased surface runoff and soil loss, and seepage occurred at the downslope end of the box, indicating saturation of the near‐surface, unfrozen soil. During the early stage of the rainfall, soil loss was particularly greater than during the latter half of the rainfall experiment although both showed a similar surface runoff rate. Saturation of the near‐surface soil was the reason for the greater soil loss rate, while a surface seal restricted soil loss by surface runoff during the latter half of the rainfall experiment.
Satellite‐Based Detection of Salinity and Sodicity Impacts on Wheat Production in the Mexicali Valley
Authors: Seifert Christopher , Ortiz-Monasterio J. Ivan , Lobell David B.
Published: September 2012

Sodicity and salinity are known constraints on wheat (Triticum aestivum L.) yields in many agricultural areas, especially for irrigated wheat. Objective estimates of the effects of these soil properties across broad scales are often difficult due to the effects of climate, management regimes, and diseases. This study used a satellite‐derived, 9‐yr yield data set combined with a data set of 8561 soil samples to estimate the effects of sodicity and salinity on wheat yield and the area under production in northwestern Mexico's Mexicali Valley. The results for salinity showed some yield reductions but were largely inconclusive. Sodicity, however, appears to account for an average loss of 1.2% of wheat production each year by harming fields sown to wheat, with negative yield effects seen on at least 32% of land in the data set. We estimate that an additional 1.2% of wheat production in the valley is forgone by farmers avoiding sowing on sodic soils. Yields appear to be negatively affected at an exchangeable Na percentage (ESP) of 6, much lower than the commonly accepted threshold of 15. The results of this study indicate that sodic fields tend to be planted less often and have lower wheat yields in the Mexicali Valley. Total production impacts are on the order of a few percentage points, which is small relative to the total gap between average and maximum on‐farm yields.
Computation of Slope Movements Initiated by Rain–Induced Shear Bands in Small–Scale Tests and In Situ
Authors: Ehlers W. , Avci O. , Markert B.
Published: September 2012

Computational investigations of the complex flow and deformation processes of natural slopes within a continuum‐mechanical approach become more and more important due to an increasing number of slope movements and slope failure situations caused by heavy rainfall events. Numerical simulations of hillslopes can support the detection of various coupled failure mechanisms by simply changing the initial and boundary conditions of the considered initial‐boundary‐value problem. This procedure can contribute to a deeper and better understanding of various complex slope failure processes. In this study, the slope system, generally understood as an unsaturated soil, was considered as a triphasic material consisting of a soil skeleton, such as sand, a pore liquid, such as water, and a pore gas, such as air. The model was embedded in the well‐founded theory of porous media, while numerical solutions were realized by use of the finite‐element solver PANDAS. Proceeding from cohesionless sand as the basic soil under study, the material parameters governing the soil behavior were taken from triaxial experiments on dry sand specimens performed under homogeneous loading conditions, whereas the parameters governing the hydraulic behavior were determined by experiments on saturated soil specimens under nondeforming conditions. Furthermore, numerical investigations of slope failure scenarios under different loading conditions were compared with each other to find out how the pore water influences the failure behavior. The computations reveal a strong coupling between the soil deformation and the hydraulic behavior during failure processes. Finally, the flow and deformation behavior of the natural Heumoes slope in Ebnit situated near Dornbirn in the eastern part of the Voralberg Alps (Austria) was studied qualitatively. Unfortunately, this slope is still in motion.
Alternative Analytical Expressions for the General van Genuchten–Mualem and van Genuchten–Burdine Hydraulic Conductivity Models
Authors: Dourado Neto D. , de Jong van Lier Q. , van Genuchten M.Th. , Reichardt K. , Metselaar K. , Nielsen D.R.
Published: September 2012

The van Genuchten expressions for the unsaturated soil hydraulic properties, first published in 1980, are used frequently in various vadose zone flow and transport applications assuming a specific relationship between the m and n soil hydraulic parameters. By comparison, probably because of the complexity of the hydraulic conductivity equations, the more general solutions with independent m and n values are rarely used. We expressed the general van Genuchten–Mualem and van Genuchten–Burdine hydraulic conductivity equations in terms of hypergeometric functions, which can be approximated by infinite series that converge rapidly for relatively large values of the van Genuchten–Mualem parameter n but only very slowly when n is close to one. Alternative equations were derived that provide very close approximations of the analytical results. The newly proposed equations allow the use of independent values of the parameters m and n in the soil water retention model of van Genuchten for subsequent prediction of the van Genuchten–Mualem and van Genuchten–Burdine hydraulic conductivity models, thus providing more flexibility in fitting experimental pressure‐head‐dependent water content, θ(h), and hydraulic conductivity, K(h), or K(θ) data.
Predicting the Soil Moisture Characteristic Curve from Particle Size Distribution with a Simple Conceptual Model
Authors: Mohammadi Mohammad Hossein , Vanclooster Marnik
Published: September 2012

Indirect methods for predicting the soil moisture characteristic curve (SMC) from the particle size distribution (PSD) often rely on empirical coefficients, which limits their applicability to independent data sets. We have developed a robust simple PSD‐based conceptual SMC prediction model and evaluated the model performance through comparisons with the Haverkamp and Parlange (HP) and Arya and Paris (AP) models. Following the AP model, we divided the PSD into n size fractions where each fraction contained spherical particles whose packing state is described by a parameter. The moisture content is subsequently calculated from the PSD and measured saturated moisture content. The packing state is estimated from particle and bulk densities. The suction head is predicted based on the particle size, assuming a linear relationship between the suction head and packing state. Our results showed that the model can adequately predict the SMC as measured in 80 soils selected from the UNSODA database. It was also shown that the proposed model provides better predictions of SMC than the AP or HP models. The model underestimates the moisture content in the dry range of the SMC. We attribute this bias to the incomplete desorption of residual water coated on soil particles or water retained within nonspherical particles with high surface energy contents. We conclude that the main advantage of our model is the robustness and independency of model performance on soil type, allowing improving predictions of SMC from PSD at larger watershed scales.
Correction of Temperature and Electrical Conductivity Effects on Dielectric Permittivity Measurements with ECH2O Sensors
Authors: Rosenbaum U. , Huisman J. A. , Vrba J. , Vereecken H. , Bogena H. R.
Published: September 2012

The measurement accuracy of low‐cost electromagnetic soil water content sensors is often deteriorated by temperature and soil bulk electrical conductivity effects. This study aimed to quantify these effects for the ECH2O EC‐5 and 5TE sensors and to derive and test correction functions. In a first experiment, the temperature of eight reference liquids with permittivity ranging from 7 to 42 was varied from 5 to 40°C. Both sensor types showed an underestimation of permittivity for low temperature (5–25°C) and an overestimation for high temperature (25–40°C). Next, NaCl was added to increase the conductivity of the reference liquids (up to ∼2.5 dS m−1 for a permittivity of 26–42, up to ∼1.5 dS m−1 for a permittivity of 22–26). The permittivity measured with both sensors showed a strong and complicated dependence on electrical conductivity, with both under‐ and overestimation of permittivity. Using these experimental data, we derived empirical correction functions. The performance of the correction functions for the 5TE sensor was evaluated using coarse sand and silty clay loam soil samples. After correcting for temperature effects, the measured permittivity corresponded well with theoretical predictions from a dielectric mixing model for soil with low electrical conductivity. The conductivity correction function also improved the accuracy of the soil moisture measurements, but only within the validity range of this function. Finally, both temperature and electrical conductivity of the silty clay loam were varied and a sequential application of both correction functions also resulted in permittivity measurements that corresponded well with model predictions.
Water and Oxygen Dependence of Pseudomonas putida Growing in Silica Sand Capillary Fringes
Authors: Jost Daniel , Winter Josef , Gallert Claudia
Published: September 2012

In tests with Hele–Shaw cells containing silica sand, O2 profiles were measured after formation of a capillary fringe (CF) with a nutrient broth, that was inoculated with Pseudomonas putida. After 7 d, the CF became anaerobic up to 2 cm above the water level. Within the next 3 cm at decreasing water saturation, the O2 concentration approached its maximum value. After growth, most P. putida cells were found at the 4‐ to 5‐cm height of the CF, whereas cell densities decreased significantly toward the top of the CF due to water‐limited respiratory activity. This was shown in separate batch experiments by measuring respiration rates of P. putida for defined water saturations. In silica sand (rough surface) or glass beads (smooth surface), respiration of P. putida was significantly reduced at a water saturation of ≤7.5% but was always higher for growth on sand than on glass beads, presumably due to different water bioavailability at the surface. The highest O2 consumption rates of P. putida in both media were measured at 60 to 85% water saturation, which represents the saturated–unsaturated interface region in a CF. To find the minimum required water availability for respiration, batch assays with increasing agar concentrations in LB medium were conducted. The O2 consumption rates of P. putida decreased to zero above an agar concentration of 18% (w/v), equivalent to a water activity <0.978. The results indicate that limited bacterial respiration due to water potential stress would only occur in the top few millimeters of a CF in sand.
Optimization of a Filter‐Lysis Protocol to Purify Rat Testicular Homogenates for Automated Spermatid Counting
Authors: Pacheco Sara E. , Anderson Linnea M. , Boekelheide Kim
Published: September 2012

Abstract: Quantifying testicular homogenization‐resistant spermatid heads (HRSH) is a powerful indicator of spermatogenesis. These counts have traditionally been performed manually using a hemocytometer, but this method can be time consuming and biased. We aimed to develop a protocol to reduce debris for the application of automated counting, which would allow for efficient and unbiased quantification of rat HRSH. We developed a filter‐lysis protocol that effectively removes debris from rat testicular homogenates. After filtering and lysing the homogenates, we found no statistical differences between manual (classic and filter‐lysis) and automated (filter‐lysis) counts using 1‐way analysis of variance with Bonferroni's multiple comparison test. In addition, Pearson's correlation coefficients were calculated to compare the counting methods, and there was a strong correlation between the classic manual counts and the filter‐lysis manual (r = 0.85, P = .002) and the filter‐lysis automated (r = 0.89, P = .0005) counts. We also tested the utility of the automated method in a low‐dose exposure model known to decrease HRSH. Adult Fischer 344 rats exposed to 0.33% 2,5‐hexanedione in the drinking water for 12 weeks demonstrated decreased body (P = .02) and testes (P = .002) weights. In addition, there was a significant reduction in the number of HRSH per testis (P = .002) when compared to controls. A filterlysis protocol was optimized to purify rat testicular homogenates for automated HRSH counts. Automated counting systems yield unbiased data and can be applied to detect changes in the testis after low‐dose toxicant exposure.
Effects of Icariside II on Improving Erectile Function in Rats With Streptozotocin‐Induced Diabetes
Authors: Zhou Feng , Xin Hua , Liu Tao , Li Guang‐Yong , Gao Zhe‐Zhu , Liu Jing , Li Wei‐Ren , Cui Wan‐Shou , Bai Guang‐Yi , Park Nam Cheol , Xin Zhong Cheng
Published: September 2012

Abstract: Icariin and icariside II (ICA II), 2 active components isolated from herba epimedii, have a closely structural relationship. There is evidence that icariin may be useful in the treatment of erectile dysfunction (ED); however, the study on the therapeutic efficacy of ICA II on ED is currently scant. We investigated the effects of ICA II on improving erectile function of rats with streptozocin‐induced diabetes. Fifty 8‐week‐old Sprague‐Dawley rats were randomly distributed into normal control and diabetic groups. Diabetes was induced by a one‐time intraperitoneal injection of streptozocin (60 mg/kg). Three days later, the diabetic rats were randomly divided into 4 groups including a saline‐treated placebo arm and 3 ICA II‐treated models (1, 5, and 10 mg/kg/d). After 3 months, penile hemodynamics was measured by cavernous nerve electrostimulation (CNE) with real time intracorporal pressure assessment. Penises were harvested with subsequent histological examination (picrosirius red stain, Hart elastin stain, and immunohistochemical stain) and Western blots to explore the expression of the nitric oxide‐cyclic guanosine monophosphate (NO‐cGMP) and transforming growth factor β1 (TGFβ1)/Smad2 signaling pathways. Diabetes significantly attenuated erectile responses to CNE. Diabetic rats had decreased corpus cavernosum smooth muscle/collagen ratio and endothelial cell content relative to the control group. The ratio of collagen I to III was significantly lower in the corpora of diabetic rats; furthermore, cavernous elastic fibers were fragmented in the diabetic animals. Neuronal nitric oxide synthase (nNOS), endothelial nitric oxide synthase, and vascular endothelial growth factor were expressed at lower levels in the diabetic group; ICA II‐treated diabetic rats had higher expression in the penis relative to placebo‐treated diabetic animals. Both the TGFβ1/Smad2/connective tissue growth factor (CTGF) signaling pathway and apoptosis were down‐regulated in the penis from ICA II‐treated rats. ICA II treatment attenuates diabetes‐related impairment of penile hemodynamics, likely by increasing smooth muscle, endothelial function, and nNOS expression. ICA II could alter corpus cavernosum fibrous‐muscular pathological structure in diabetic rats, which could be regulated by the TGFβ1/Smad2/CTGF and NO‐cGMP signaling pathways.
Imaging Diagnosis, Transurethral Endoscopic Observation, and Management of 43 Cases of Persistent and Refractory Hematospermia
Authors: Li Yan‐Feng , Liang Pei‐He , Sun Zhong‐Yi , Zhang Yong , Bi Gang , Zhou Bo , Li Ke , Bai Wei , Wang Luo‐Fu , Zhang Jun , Jin Feng‐Shuo
Published: September 2012

Abstract: The goal of this study was to explore minimally invasive transurethral imaging and surgery for the treatment of severe, persistent hematospermia in cases that were refractory to conservative treatments. The study included 43 patients (aged 22–77 years; average, 44.6 years) with long‐lasting, severe hematospermia, accompanied by discomfort or pain in the lumbosacral or perineal region, dysuria, frequent micturition, decreased semen volume, and/or azoospermia. Patient symptoms had persisted for 1 to 10 years (average, 5.3 years). Computed tomography or magnetic resonance imaging of each patient was evaluated, and transurethral surgery was performed. The causes of hematospermia were identified in all 43 patients, and their ejaculatory duct obstruction or seminal vesiculitis was successfully treated. No serious intraoperative or postoperative complications occurred. Pathologic analyses revealed that all of the resected or biopsied seminal vesicle tissues had chronic nonspecific inflammation in the seminal vesicle wall, and no tumors were identified. Preoperative symptomology of hematospermia disappeared in all patients followed up for 2 to 30 months (average, 16 months). A single patient experienced recurrence at 11 months and had a second minimally invasive surgery that was curative. A total of 95.3% (41 of 43) of the patients experienced normal orgasmic intensity after surgery. Magnetic resonance imaging is a valuable and accurate diagnostic method for the identification of causative factors underlying hematospermia. Transurethral dilation of ejaculatory ducts, incision of the verumontanum or the distal end of the ejaculatory ducts, and incision or resection of the relevant cysts represent simple, safe, and reliable approaches for the management of refractory cases of hematospermia that do not respond to conservative treatments.
Fabrication of superhydrophobic surface of stearic acid grafted zinc by using an aqueous plasma etching technique
Authors: Gao Jinzhang , Li Yaping , Li Yan , Liu Hongwei , Yang Wu
Published: September 2012

A stable superhydrophobic surface of stearic acid grafted zinc was fabricated with two steps, that is, the zinc surface was firstly treated with glow discharge electrolysis plasma (GDEP) and then followed by a grafted reaction of stearic acid onto the treated zinc surface. Results indicated that the wettability of zinc substrate changed from superhydrophily to superhyphodrobicity with a water contact angle (CA) up to 158° and a water sliding angle (SA) less than 5°. The surface morphology and composition were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively.
Extraction properties of β-aminophosphine oxides towards lanthanides and alkaline earth metals
Authors: Matveeva Ekaterina , Sharova Elena , Turanov Alexander , Karandashev Vasilii , Odinets Irina
Published: September 2012

The investigation of the extraction properties of a series of polyoligodentate β-aminophosphine oxides 1–8 bearing from one to six phosphine oxide groups in a molecule towards Ln(III) and alkaline earth metals ions from neutral media has revealed that, using common diluents, the extraction efficiency increases with an increase of a number of P=O functions in a ligand. The addition of ionic liquid, namely 1-butyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([bmim][NTf2]), significantly increasing the extraction efficiency and application of IL concentration of 0.05 M (in 1,2-dichloroethane) providing the maximum recovery of metal ions with Lu/La separation factor reaching up to 91. Hexapodal tris[bis(2-diphenylphosphorylethyl)aminoethyl]amine 8 demonstrates the highest extraction under all conditions applied and the separation factor for U and Eu of this compound exceeded 103.
A concise synthesis of enantiomerically pure aroyl-l-alanines and dihydroaroyl-l-alanines
Authors: Gardiánová Mária , Slížik Ľuboš , Koreňová Anna , Považanec František , Berkeš Dušan
Published: September 2012

Straightforward preparation of enantiomerically highly enriched N-substituted aroylalanines has been developed. This process involves the combination of crystallization-induced asymmetric transformation and a conjugate addition of N-nucleophiles to the corresponding aroylacrylic acids. Further transformations to 3,4-dichlorobenzoylalanine and aroyl-l-alanines via periodate oxidation and stereoselective reduction to N-substituted syn-4-aryl-4-hydroxy-2-aminobutanoic acids are also described.
Spectral characterisation of new organic fluorescent dyes with an alkoxysilane moiety and their utilisation for the labelling of layered silicates
Authors: Danko Martin , Mičušík Matej , Omastová Mária , Bujdák Juraj , Chorvát Dušan
Published: September 2012

New fluorescence dyes with an alkoxysilane moiety were synthesised by the condensation of 3-(triethoxysilyl)-1-propanamine (3-aminopropyltriethoxysilane) with 4,10-benzothioxanthene-3,1′-dicarboxylic acid anhydride (BTXA) and N,N-dimethylaminonaphthalene-1,8-dicarboxylic acid anhydride (DMANA), which was accompanied by the formation of an imidic bridge. The compounds N-(3-(triethoxysilyl)propyl)-thioxantheno[2,1,9-dej]isoquinoline-1,3-dione (BTX-S) and 4-(N′, N′-dimethyl)-N-(triethoxysilyl)propyl-1,8-naphthalene dicarboxylic acid imide (DMAN-S) were characterised by steady-state and time-resolved fluorescence spectroscopy in chloroform and ethanol. Both conjugates (BTX-S and DMAN-S) exhibited absorption and emission bands in the same region as the un-substituted BTXA and DMANA. An important Stokes shift was observed for DMAN-S in ethanol. A high fluorescence quantum yield was observed for BTX-S in both solvents and for DMAN-S in chloroform. In addition, the newly developed fluorescent silane dyes were covalently attached to the microscopic particles of layered silicates and on the surface of SiO2 wafers as a proof of concept for fluorescence particle (surface) visualisation. The surface wafer modification was precisely characterised by X-ray photoelectron spectroscopy (XPS). Successful covalent linkage onto the particles of layered silicates was proved by confocal laser scanning microscopy technique.
Conjugated push-pull salts derived from linear benzobisthiazole: preparation and optical properties
Authors: Čibová Alexandra , Magdolen Peter , Fülöpová Andrea , Zahradník Pavol
Published: September 2012

A series of novel monomethylated salts derived from linear benzobisthiazole was prepared. The push-pull attributes of these new compounds are represented by a quaternised azolium cycle as the acceptor part at one end of the structure and the dialkylamino- or diarylamino-substituted benzene ring as the donor part at the opposite end. Both moieties are connected by a conjugated linker consisting of one or two double bonds. Such dipolar structures are promising candidates for non-linear optical materials. The quantum-chemical indices describing linear and non-linear optical properties were obtained from semi-empirical calculations. The relationships between the chemical structure and non-linear optical properties of the cations studied were obtained. Effective conjugation was confirmed by measuring the optical properties in the UV-VIS region.
Gelation Behavior of 5-Chloro-8-hydroxyquinoline, an Antituberculosis Agent in Aqueous Alcohol Solutions
Authors: Kolehmainen Erkki , Salo Hannu , Korpela Jukka
Published: September 2012

It was shown that 5-chloro-8-hydroxyquinoline, an antituberculosis agent, gels aqueous alcohol solutions efficiently. Thermal stability and gel-to-sol transition temperature of 1% gel in CD3OD/D2O (2:1) was studied by 1H-NMR. Fibrous structures of four xerogels have been characterized by scanning electron microscope.
Protective Effect of Anthocyanin from Lonicera Caerulea var. Edulis on Radiation-Induced Damage in Mice
Authors: Zhao Haitian , Wang Zhenyu , Ma Fengming , Yang Xin , Cheng Cuilin , Yao Lei
Published: September 2012

The radioprotective effect of anthocyanin extracted from Lonicera caerulea var. edulis (ALC), was studied in ICR mice. Different doses of ALC were intragastrically administered to mice once a day, prior to radiation. After two weeks, the mice received a one-time 5 Gy whole body 60Coγ radiation. The spleen index, thymus index, activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), malondialdehyde (MDA) content, and glutathione (GSH) content in liver tissue were measured. Compared with the radiation control group, the levels of MDA in all ALC treated groups decreased significantly (p < 0.05). Moreover, the GSH content, activities of SOD and GSH-Px in liver tissue were enhanced significantly (p < 0.05) in all ALC groups. These results demonstrate that ALC may be a potential radioprotector, and a further study of the molecular mechanism is needed for further application.
Mechanisms of Oxidative Damage in Multiple Sclerosis and Neurodegenerative Diseases: Therapeutic Modulation via Fumaric Acid Esters
Authors: Lee De-Hyung , Gold Ralf , Linker Ralf A.
Published: September 2012

Oxidative stress plays a crucial role in many neurodegenerative conditions such as Alzheimer’s disease, amyotrophic lateral sclerosis and Parkinson’s as well as Huntington’s disease. Inflammation and oxidative stress are also thought to promote tissue damage in multiple sclerosis (MS). Recent data point at an important role of anti-oxidative pathways for tissue protection in chronic-progressive MS, particularly involving the transcription factor nuclear factor (erythroid-derived 2)-related factor 2 (Nrf2). Thus, novel therapeutics enhancing cellular resistance to free radicals could prove useful for MS treatment. Here, fumaric acid esters (FAE) are a new, orally available treatment option which had already been tested in phase II/III MS trials demonstrating beneficial effects on relapse rates and magnetic resonance imaging markers. In vitro, application of dimethylfumarate (DMF) leads to stabilization of Nrf2, activation of Nrf2-dependent transcriptional activity and abundant synthesis of detoxifying proteins. Furthermore, application of FAE involves direct modification of the inhibitor of Nrf2, Kelch-like ECH-associated protein 1. On cellular levels, the application of FAE enhances neuronal survival and protects astrocytes against oxidative stress. Increased levels of Nrf2 are detected in the central nervous system of DMF treated mice suffering from experimental autoimmune encephalomyelitis (EAE), an animal model of MS. In EAE, DMF ameliorates the disease course and improves preservation of myelin, axons and neurons. Finally, Nrf2 is also up-regulated in the spinal cord of autopsy specimens from untreated patients with MS, probably as part of a naturally occurring anti-oxidative response. In summary, oxidative stress and anti-oxidative pathways are important players in MS pathophysiology and constitute a promising target for future MS therapies like FAE.
Studies on the Interactions of Copper and Zinc Ions with β-Amyloid Peptides by a Surface Plasmon Resonance Biosensor
Authors: Yao Fujun , Zhang Ruiping , Tian He , Li Xiangjun
Published: September 2012

The aggregation of β-amyloid peptide (Aβ) into fibrils plays an important role in the pathogenesis of Alzheimer’s disease (AD). Metal ions including copper and zinc are closely connected to the precipitation and toxicity of Aβ. In this study, a surface plasmon resonance (SPR) biosensor was constructed to investigate the interactions between Aβ and metal ions. Aβ peptide was immobilized on the SPR chip surface through a preformed alkanethiol self-assembled monolayer (SAM). Our observations indicate that the immobilized Aβ undergoes a conformational change upon exposure to the metal ions. A difference in metal binding affinity between Aβ1–28 and Aβ1–42 was also detected. The results suggest that SPR is an effective method to characterize the interactions between Aβ and metal ions.
The Heterochromatic Barrier to DNA Double Strand Break Repair: How to Get the Entry Visa
Authors: Goodarzi Aaron A. , Jeggo Penny A.
Published: September 2012

Over recent decades, a deep understanding of pathways that repair DNA double strand breaks (DSB) has been gained from biochemical, structural, biophysical and cellular studies. DNA non-homologous end-joining (NHEJ) and homologous recombination (HR) represent the two major DSB repair pathways, and both processes are now well understood. Recent work has demonstrated that the chromatin environment at a DSB significantly impacts upon DSB repair and that, moreover, dramatic modifications arise in the chromatin surrounding a DSB. Chromatin is broadly divided into open, transcriptionally active, euchromatin (EC) and highly compacted, transcriptionally inert, heterochromatin (HC), although these represent extremes of a spectrum. The HC superstructure restricts both DSB repair and damage response signaling. Moreover, DSBs within HC (HC-DSBs) are rapidly relocalized to the EC-HC interface. The damage response protein kinase, ataxia telangiectasia mutated (ATM), is required for HC-DSB repair but is dispensable for the relocalization of HC-DSBs. It has been proposed that ATM signaling enhances HC relaxation in the DSB vicinity and that this is a prerequisite for HC-DSB repair. Hence, ATM is essential for repair of HC-DSBs. Here, we discuss how HC impacts upon the response to DSBs and how ATM overcomes the barrier that HC poses to repair.
Understanding Tourist Perspectives on Geotourism Experience: Implications for Destination Development
Authors: Kim Aise Kyoungjin , Brown Graham
Published: September 2012

In recent years, geotourism has emerged as a distinctive form of nature-based tourism but there is little understanding of the extent to which geotourism experiences influence tourist decisions and behavior. As geotourism is still in its infancy in many destinations, there is a lack
of research on understanding the characteristics of geotourists, including their actual interests, expectations, preferences, satisfaction, and behavior. This article reports the findings of a study which examined the profile of people visiting the Flinders Ranges region of South Australia,
which is promoted as a geotourism destination. A survey of visitors identified three market segments which differed with respect to travel behavior and experiential outcomes. The findings are used to question the current status of the geotourism market and to discuss destination development
strategies that reflect opportunities presented by different market segments.