Tillage and land use effects on soil microporosity in Ohio, USA and Kolombangara, Solomon Islands

Micropores are important to soil moisture retention and plant growth. Microporosity and pore size distribution were evaluated using mercury intrusion porosimetery on aggregates from 35-year-old experiments started in 1962 at Wooster (40.5 °N, 82 °W) and South Charleston (39.8 °N, 84 °W) in Ohio, USA and from three land use practices on Kolombangara (8 °S, 157 °E) in Solomon Islands. Tillage treatments in Ohio included: moldboard plowing (MP), chisel plowing (CP), and no-till (NT) with continuous corn. The land use treatments in Kolombangara included: natural forest (NF), traditional farming (TF) and topsoil removal (TR). Pore size measured in aggregates ranged from 0.2 to 100 μm in diameter. Median pore radius was significantly (P < 0.05) larger for NT than for MP and CP treatments at Wooster, but not at South Charleston. Tillage treatments had significant effect on the volume of both storage and residual pores for both sites in Ohio. Volume of storage and residual pores were higher for Wooster than South Charleston soil. At Kolombangara, the NF treatment had significantly larger median and peak pore radii, and microporosity than TF and TR treatments. There was, however, no significant difference among treatments in the volume of pore size distribution. These data support a recommendation for adoption of no-till or conservation tillage in soils of the temperate region, and of minimal disturbance and effective erosion control in soils of the tropics.     

Present state of imposex in neptune whelk Neptunea arthritica inhabiting shallow waters around Hokkaido, Japan

ABSTRACT:   The state of imposex in Neptunea arthritica from seven sites along the coast of Hokkaido, Japan was examined in 2002 based on the criteria: (i) relative penis size index (RPSI); (ii) imposex frequency; (iii) stage frequency distribution of imposex in adult and immature whelks; and (iv) sex ratio. RPSI differed from site to site, although values from all sites were low (0.186–5.294). In particular, the RPSI values for four sites were very low (<1.0). In sites where immature whelks were also collected, the frequency of imposex was considerably lower in immature (7.7%–55.6%) than in adult whelks (50%–95.2%) except at one site. The imposex stage frequency distribution also differed among sites, and the trend in the adult whelks corresponded with their RPSI value. Female whelks showing severe imposex (Stage 3 and 3+) were restricted to large individuals.     

Capricious bioinvasions versus uncoordinated management strategies: how the most unlikely invaders can prosper under the current UK legislation framework

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Interactions between Escherichia coli and allophane—I. Adsorption

Sorptive interactions between Escherichia coli (ATCC 11303B) and a purified allophane clay fraction were studied quantitatively using electronic particle counting and electrophoresis. Adsorption was influenced by pH and ions present at the allophane surface. These effects could be rationalized by considering changes in the net surface charge of the components. Electronic particle counting studies at pH 5.5 and above gave adsorption isotherms that obeyed single-term Langmuir kinetics. At pH 4.5, a more complex two-step isotherm was obtained, which was attributed to aggregation of unadsorbed cells by Al solubilized from the allophane surface.     

Chitosan-Based Films with 2-Aminothiophene Derivative: Formulation,Characterization and Potential Antifungal Activity

In this study, films of chitosan and 2-amino-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carbonitrile (6CN), a 2-aminothiophene derivative with great pharmacological potential, were prepared as a system for a topical formulation. 6CN-chitosan films were characterized by physicochemical analyses, such as Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and scanning electronic microscopy (SEM). Additionally, the antifungal potential of the films was evaluated in vitro against three species of Candida (C. albicans, C. tropicalis, and C. parapsilosis). The results of the FTIR and thermal analysis showed the incorporation of 6CN in the polymer matrix. In the diffractogram, the 6CN-chitosan films exhibited diffraction halos that were characteristic of amorphous structures, while the micrographs showed that 6CN particles were dispersed in the chitosan matrix, exhibiting pores and cracks on the film surface. In addition, the results of antifungal investigation demonstrated that 6CN-chitosan films were effective against Candida species showing potential for application as a new antifungal drug.     

Neuroanatomical distribution and partial sequence of cDNA encoding brain cytochrome P450 aromatase (P450aromB) in pejerrey Odontesthes bonariensis

The molecular cloning of a cDNA encoding the pejerrey brain cytochrome P450 aromatase (P450aromB) is described. This form shares higher identity to other brain aromatases than with their respective ovarian counterparts and the self ovarian aromatase. Tissue-specific expression of both aromatases was examined in pejerrey by RT-PCR. The immunocytochemical distribution of P450aromB was described.     

Assemblage patterns of fish functional groups relative to habitat connectivity and conditions in floodplain lakes

Miyazono S, Aycock JN, Miranda LE, Tietjen TE. Assemblage patterns of fish functional groups relative to habitat connectivity and conditions in floodplain lakes.
Ecology of Freshwater Fish 2010: 19: 578–585. © 2010 John Wiley & Sons A/S Abstract – We evaluated the influences of habitat connectivity and local environmental factors on the distribution and abundance patterns of fish functional groups in 17 floodplain lakes in the Yazoo River Basin, USA. The results of univariate and multivariate analyses showed that species–environmental relationships varied with the functional groups. Species richness and assemblage structure of periodic strategists showed strong and positive correlations with habitat connectivity. Densities of most equilibrium and opportunistic strategists decreased with habitat connectivity. Densities of certain equilibrium and opportunistic strategists increased with turbidity. Forested wetlands around the lakes were positively related to the densities of periodic and equilibrium strategists. These results suggest that decreases in habitat connectivity, forested wetland buffers and water quality resulting from environmental manipulations may cause local extinction of certain fish taxa and accelerate the dominance of tolerant fishes in floodplain lakes.     

Effect of glyphosate on the tripartite symbiosis formed by Glomus intraradices,Bradyrhizobium japonicum,and genetically modified soybean

Most soybeans grown in North America are genetically modified (GM) to tolerate applications of the broad-spectrum herbicide glyphosate; as a result, glyphosate is now extensively used in soybean cropping systems. Soybean roots form both arbuscular mycorrhizal (AM) and rhizobial symbioses. In addition to individually improving host plant fitness, these symbioses also interact to influence the functioning of each symbiosis, thereby establishing a tripartite symbiosis. The objectives of this study were to (1) estimate the effects of glyphosate on the establishment and functioning of AM and rhizobial symbioses with GM soybean, and (2) to estimate the interdependence of the symbioses in determining the response of each symbiosis to glyphosate. These objectives were addressed in two experiments; the first investigated the importance of the timing of glyphosate application in determining the responses of the symbionts and the second varied the rate of glyphosate application. Glyphosate applied at recommended field rates had no effect on Glomus intraradices or Bradyrhizobium japonicum colonization of soybean roots, or on soybean foliar tissue [P]. N₂-fixation was greater for glyphosate-treated soybean plants than for untreated-plants in both experiments, but only when glyphosate was applied at the first trifoliate soybean growth stage. These data deviate from previous studies estimating the effect of glyphosate on the rhizobial symbiosis, some of which observed negative effects on rhizobial colonization and/or N₂-fixation. We did observe evidence of the response of one symbiont (stimulation of N₂-fixation following glyphosate) being dependent on co-inoculation with the other; however, this interactive response appeared to be contextually dependent as it was not consistent between experiments. Future research needs to consider the role of environmental factors and other biota when evaluating rhizobial responses to herbicide applications.     

Characterization of house dust mite and scabies mite allergens by use of canine serum antibodies

OBJECTIVE: To identify the major allergenic proteins from the 3 main species of dust mites to which dogs react (Dermatophagoides farinae, D. pteronyssinus, and Euroglyphus maynei) and evaluate the potential cross-reactivity of dust mite allergens with antigens from the ectoparasitic mite Sarcoptes scabiei var canis. SAMPLE POPULATION: Sera from 83 dogs with atopic dermatitis. PROCEDURE: Sodium dodecylsulfate-polyacrylamide gel electrophoresis and immunoblotting using serum from atopic dogs was used to identify IgE-binding proteins in extracts of the 4 mite species. RESULTS: Sera of atopic dogs contained IgE against 23, 17, 25, and 17 allergens from D. farinae, D. pteronyssinus, E. maynei, and S. scabiei, respectively. Unlike the situation for humans, the major allergens for dogs are mostly proteins that are larger than 90 kd molecular weight. Dermatophagoides farinae and E. maynei appear to be more allergenic for dogs than is D. pteronyssinus. Some dogs with serum IgE against dust mites also had IgE against antigens of S. scabiei var canis. CONCLUSIONS AND CLINICAL RELEVANCE: Multiple dust mite allergens induce an IgE response in dogs. These allergens are mostly greater than 90 kd molecular weight.