In vitro and immunological assessment of the estrogenic activity and concentrations of 17β-estradiol, estrone, and ethinyl estradiol in treated effluent from 45 wastewater treatment plants in Victoria, Australia

The project was conducted between May 2006 and September 2007, and involved the collection of effluent samples from 45 wastewater treatment plants (WWTPs). The 45 WWTPs included 16 lagoon-based plants and 29 with activated sludge-based processes. Permission was obtained from all the relevant water authorities to collect samples of final effluent at point of discharge to the environment, whether that was to a creek, a river, the ocean, or the land. Samples were collected on two occasions, namely, in August 2006 (winter) and late February–early March 2007 (summer), and subjected to a number of biological and chemical analyses, including toxicity tests, measurement of hormonal (estrogenic) activity using yeast-based bioassays, and measurement of specific hormonal concentrations using enzyme-linked immunosorbent assays (ELISAs). Almost all of the effluents examined showed estrogenic activity: in winter, no activity to 73 ng/l 17β-estradiol equivalents (EEQ); and in summer, no activity to 20 ng/l EEQ. On the whole, the levels of estrogenic activity observed were comparable with the range recently reported in Australia and New Zealand using human estrogen receptor-based assays (“not detected” to ~10 ng/l EEQ). The low/no bioassay response was confirmed by the chemical assessment of estradiol, estrone, and ethinyl estradiol concentrations by ELISA, which returned concentrations of these compounds for the most part below 10 ng/l.

Challenging the dominant discourses of the state aid debate

The state aid debate is one of the longest running and most intractable issues in the public policy sphere in Australia. Recent decisions by the Commonwealth government to increase funding to private schools has reignited the debate. But the traditional defences of public education have proved inadequate to the task of hanging the course of current neo-liberal education policy trajectories. As the percentage of students attending private schools continues to grow, and as the spectre of a residualised public education system looms larger, so the need to rethink Australian public education becomes a more urgent project. In this paper we analyse what is happening and why; identify a range of concerns from the standpoint of a social democratic educational agenda; and theorise some possible strategies which might be pursued by those committed to a vibrant public schooling
system in Australia.

Antibody-mediated protection of plants against infection from potyviruses

Transgenic plants expressing single-chain antibodies have been produced to investigate the feasibility of antibody-mediated broad-spectrum protection against plant virus infections. This study indicates that protection against a wide range of plant viruses can be achieved in transgenic plants expressing a single antibody construct.

A cell-permeable dominant-negative survivin protein induces apoptosis and sensitizes prostate cancer cells to TNF-α therapy

BACKGROUND: Survivin is a member of the inhibitor-of-apoptosis (IAP) family which is widely expressed by many different cancers. Overexpression of survivin is associated with drug resistance in cancer cells, and reduced patient survival after chemotherapy and radiotherapy. Agents that antagonize the function of survivin hold promise for treating many forms of cancer. The purpose of this study was to investigate whether a cell-permeable dominant-negative survivin protein would demonstrate bioactivity against prostate and cervical cancer cells grown in three dimensional culture.

RESULTS: A dominant-negative survivin (C84A) protein fused to the cell penetrating peptide poly-arginine (R9) was expressed in E. coli and purified by affinity chromatography. Western blot analysis revealed that dNSurR9-C84A penetrated into 3D-cultured HeLa and DU145 cancer cells, and a cell viability assay revealed it induced cancer cell death. It increased the activities of caspase-9 and caspase-3, and rendered DU145 cells sensitive to TNF-α via by a mechanism involving activation of caspase-8.

CONCLUSIONS: The results demonstrate that antagonism of survivin function triggers the apoptosis of prostate and cervical cancer cells grown in 3D culture. It renders cancer cells sensitive to the proapoptotic affects of TNF-α, suggesting that survivin blocks the extrinsic pathway of apoptosis. Combination of the biologically active dNSurR9-C84A protein or other survivin antagonists with TNF-α therapy warrants consideration as an approach to cancer therapy.

Differences in student engagement : investigating the role of the dominant cognitive processes preferred by engineering and education students

This paper reports on a study of the differences in the dominant cognitive processes preferred by groups of engineering and education students and examines the implications of these differences for the assessment of student engagement with university courses. Concern is expressed that the items commonly used to capture student engagement data do not adequately cover the full range of the dominant cognitive processes preferred by tertiary students. The paper sets out a brief overview of student engagement along with the theory of dominant and auxiliary cognitive processes, as developed by Jung and later by Myers. Evidence is presented of the differing frequencies of the eight cognitive processes, as assessed by the Myers-Briggs Type Indicator, that are preferred by cohorts of students undertaking courses in engineering and education. The implications of these differences are discussed in the context of subject disciplines in university environments.

Swan foraging shapes spatial distribution of two submerged plants, favouring the preferred prey species

Compared to terrestrial environments, grazing intensity on belowground plant parts may be particularly strong in aquatic environments, which may have great effects on plant-community structure. We observed that the submerged macrophyte, Potamogeton pectinatus, which mainly reproduces with tubers, often grows at intermediate water depth and that P. perfoliatus, which mainly reproduces with rhizomes and turions, grows in either shallow or deep water. One mechanism behind this distributional pattern may be that swans prefer to feed on P. pectinatus tubers at intermediate water depths. We hypothesised that when swans feed on tubers in the sediment, P. perfoliatus rhizomes and turions may be damaged by the uprooting, whereas the small round tubers of P. pectinatus that escaped herbivory may be more tolerant to this bioturbation. In spring 2000, we transplanted P. perfoliatus rhizomes into a P. pectinatus stand and followed growth in plots protected and unprotected, respectively, from bird foraging. Although swan foraging reduced tuber biomass in unprotected plots, leading to lower P. pectinatus density in spring 2001, this species grew well both in protected and unprotected plots later that summer. In contrast, swan grazing had a dramatic negative effect on P. perfoliatus that persisted throughout the summer of 2001, with close to no plants in the unprotected plots and high densities in the protected plots. Our results demonstrate that herbivorous waterbirds may play a crucial role in the distribution and prevalence of specific plant species. Furthermore, since their grazing benefitted their preferred food source, the interaction between swans and P. pectinatus may be classified as ecologically mutualistic.

Small seed size increases the potential for dispersal of wetland plants by ducks

1. Long-distance dispersal (LDD) is important in plants of dynamic and ephemeral habitats. For plants of dynamic wetland habitats, waterfowl are generally considered to be important LDD vectors. However, in comparison to the internal (endozoochorous) dispersal of terrestrial plants by birds, endozoochorous dispersal of wetland plants by waterfowl has received little attention. We quantified the capacity for endozoochorous dispersal of wetland plants by waterfowl and identified the mechanisms underlying successful dispersal, by comparing the dispersal capacities of a large number of wetland plant species.

2. We selected 23 common plant species from dynamic wetland habitats and measured their seed characteristics. We fed seeds of all species to mallards (Anas platyrhynchos), a common and highly omnivorous duck species, and quantified seed gut survival, gut passage speed and subsequent germination. We then used a simple model to calculate seed dispersal distances.

3. In total 21 of the 23 species can be dispersed by mallards, with intact seed retrieval and subsequent successful germination of up to 32% of the ingested seeds. The species that pass fastest through the digestive tract of the mallards are retrieved in the greatest numbers (up to 54%) and germinate best (up to 87%). These are the species with the smallest seeds. Seed coat thickness plays only a minor role in determining intact passage through the mallard gut, but determines if ingestion enhances or reduces germination in comparison to control seeds.

4. Model calculations estimate that whereas the largest seeds can hardly be dispersed by mallards, most seeds can be dispersed up to 780 km, and the smallest seeds up to 3000 km, by mallards during migration.

5. Synthesis. This study demonstrates the mechanism underlying successful endozoochorous dispersal of wetland plant seeds by mallards: small seed size promotes rapid, and hence intact and viable, passage through the mallard gut. Mallards can disperse wetland plant seeds of all but the largest-seeded species successfully in relatively large numbers (up to 32% of ingested seeds) over long distances (up to thousands of kilometres) and are therefore important dispersal vectors.

Isolation of sperms from the pollen tube of flowering plants during fertilization

Sperm cells have been isolated from pollen tubes growing in style segments of the dicotlyledon Rhododendron macgregoriae and the monocotyledon Gladiolus gandavensis by the in vivo/in vitro method at various stages of fertilization. Pollen tubes emerged from the cut end of the style into agar medium, and more than 95% contained sperm cells. Sperm cells were released from the pollen tubes by osmotic shock or by placing styles in wall-degrading enzymes: 0.5% macerozyme and 1% cellulase. The isolated sperms were ellipsoidal protoplasts of diameter about 2 × 3 micrometers in Gladiolus and about 3 × 4 micrometers in Rhododendron. After isolation, a proportion of the sperm cells occurred in pairs linked at one end by finger-like connections. The pairs of isolated sperms were dimorphic in terms of surface area and volume. By cutting the styles at various positions and times after pollination, the potential exists to detect changes in sperm gene expression associated with fertilization.