Initiation of a Sarcocystis neurona expressed sequence tag (EST) sequencing project: a preliminary report

To accelerate genetic and molecular characterization of Sarcocystis neurona, the primary causative agent of equine protozoal myeloencephalitis (EPM), a sequencing project has been initiated that will generate approximately 7000-8000 expressed sequence tags (ESTs) from this apicomplexan parasite. Poly(A)(+) RNA was isolated from culture-derived S. neurona merozoites, and a cDNA library was constructed in a unidirectional lambda phage cloning vector. Sixty phage clones were randomly picked from the library, and the cDNA inserts were amplified from these clones using the T3 and T7 primers that flank the multi-cloning site of the lambda vector. This analysis demonstrated that 100% (60/60) of the clones selected from this library contained recombinant cDNA inserts ranging in size from 0.4 to 4.0 kilobases (kb) with an average size of 1.23kb. Single-pass sequencing from the 5' end of the 60 amplified cDNAs produced high-quality nucleotide sequence from 53 of the clones. Comparison of these ESTs to the current gene databases revealed significant matches for 10 of the ESTs, six of which are similar to sequences from other Apicomplexa (i.e., Toxoplasma gondii). Importantly, none of the ESTs were of obvious mammalian origin, thus indicating that the cDNAs in this library were derived primarily from parasite mRNA and not from mRNA of the bovine turbinate host cells. Collectively, these data indicate that the described cDNA library will provide an excellent substrate for generating a portion of the ESTs that are planned from S. neurona. This sequencing project will greatly hasten gene discovery for this protozoan pathogen thereby enhancing efforts towards the development of improved diagnostics, treatments, and preventatives for EPM. In addition, the S. neurona ESTs will represent a significant contribution to the extensive database of sequences from the Apicomplexa. Comparative analyses of these apicomplexan sequences will likely offer a multitude of important information about the biology and evolutionary history of this phylogenetic grouping of parasites.     

Regional differences in aspen (Populus tremuloides Michx.) seedling response to an established nursery protocol

New Forests - In seedling-based reforestation operations, seed source is known to be an influential variable affecting outplanting success. Adaptive variation among seed sources may also be an...     

Managing small remnants of native forest to increase biodiversity within plantation landscapes in the south west of Western Australia

Recent expansion of industrial-scale plantations into agricultural areas in Australia has the potential to assist biodiversity conservation by rehabilitating ecosystems at the landscape scale and reducing edge effects, isolation and disturbance within remnants of native vegetation. However, the efficient management of remnants for biodiversity within a plantation estate requires knowledge of both the causes and the consequences of remnant degradation. With this in mind, we examined key ecosystem features and processes relating to soil chemistry, decomposition, native tree health and regeneration and vertebrate abundance, within small forest remnants (1-4 ha) embedded within Eucalyptus globulus plantations in south west Western Australia. Soil nutrient enrichment was significantly associated with a scale of vegetation modification in order from: (1) intact forest, (2) remnants with native understorey (UDN), (3) remnants with exotic understorey (UDE), (4) plantation and (5) pasture. We propose that, in this region, UDE remnants will often remain in a degraded state even after plantation establishment and the cessation of stock grazing. This is due, in part, to more rapid rates of nutrient turnover sustaining higher nutrient availability in the soil following the replacement of ligneous understorey plants with annual ones. Cotton strips placed in surface soils were often disintegrated in UDE remnants and largely intact in UDN remnants, indicating that decomposition was accelerated in the former. Continued tree decline and regeneration failure within UDE remnants will also reinforce the UDE condition. There was less canopy seed set and little or no seedling establishment in UDE remnants compared to UDN remnants. Therefore, management interventions to assist native tree regeneration in UDE remnants are needed. Fauna trapping highlighted the desirability of retaining, and preferably restoring, small remnants in plantations. Small native mammals were found exclusively in remnants and fewer introduced Mus musculus were present in UDN remnants. Higher numbers of native lizards were found in UDN remnants, but this result was not significant (marginally).     

In situ determination of the nanoscale chemistry and behavior of solid-liquid systems

Many fundamental questions in crystal-growth behavior remain unanswered because of the difficulties encountered in simultaneously observing phases and determining elemental concentrations and redistributions while crystals nucleate and grow at the nanoscale. We show that these obstacles can be overcome by performing energy-dispersive x-ray spectroscopy on partially molten Al-Si-Cu-Mg alloy particles during in situ heating in a transmission electron microscope. Using this technique, we were able to (i) determine that the aluminum and silicon concentrations change in a complementary and symmetric manner about the solid-liquid interface as a function of temperature; (ii) directly measure the solid- and liquid-phase compositions at equilibrium and in highly undercooled conditions for quantitative comparison with thermodynamic calculations of the liquidus and solidus phase boundaries; and (iii) provide direct evidence for homogeneous nucleation of the aluminum-rich solid.     

Calcium silicate slag reduces drought stress in rice (Oryza sativa L.)

Silicon has been reported to reduce drought stress on many crops, but limited studies have evaluated this effect with rice using calcium silicate slag from the phosphorus fertilizer industry as a source of Si. A greenhouse study was performed to address this issue. Four slag rates (0, 1,000, 2,000 and 4,000 mg/kg) and two application methods (surface application and incorporation) were evaluated under two moisture regimes (flood and 50% field capacity) for drought stress mitigation in a mineral soil that is typical for rice production. Slag application significantly elevated plant‐available Si in the soil and Si accumulation in plant tissues, and tended to improve rice shoot and root biomass relative to the untreated control under both flooding and drought stress. Increased carbon isotope discrimination (△¹³C) and decreased proline in rice leaves subjected to drought stress indicate that this slag may reduce drought stress in rice, which was supported by restoration of foliage density, transpiration, photosynthesis rate and sugar accumulation to at or near flooded levels following the highest slag application. This study supports the usage of calcium silicate slag in rice production as it could improve Si availability and reduce drought stress.     

Globalization and Restructuring during Downturns: A Case Study of California

Restructuring through foreign outsourcing, whereby greater imports of manufactured inputs substitute for blue‐collar labor, is shown to intensify when industries experience declines in sales. The magnitude of this effect was four to seven times greater in California industries experiencing a 20 percent sales decline from 1987‐1992, relative to those industries whose sales dropped by 5 percent. Foreign outsourcing explains a quarter to two‐fifths of the rise in payroll inequality between blue and white collar workers in California and perhaps five to ten percent of the rise in the remainder of the U.S. Past work linked growing inequality with foreign outsourcing and restructuring with economic downturns. Here, foreign outsourcing is used as an example of a particular efficiency augmenting measure, which occurs predominantly, though not exclusively, in troubled industries.