Turtles in trouble. Conservation ecology and priorities for Australian freshwater turtles

The Australian freshwater turtle fauna is dominated by species in the family Chelidae. The extant fauna comprises a series of distinct lineages, each of considerable antiquity, relicts of a more extensive and perhaps diverse fauna that existed when wetter climes prevailed. Several phylogenetically distinctive species are restricted to single, often small, drainage basins, which presents challenges for their conservation. Specific threats include water resource development, which alters the magnitude, frequency, and timing of flows and converts lentic to lotic habitat via dams and weirs, fragmentation of habitat, sedimentation, nutrification, and a reduction in the frequency and extent of floodplain flooding. Drainage of wetlands and altered land use are of particular concern for some species that are now very restricted in range and critically endangered. The introduced European red fox is a devastatingly efficient predator of turtle nests and can have a major impact on recruitment. In the north, species such as the northern snake-necked turtle are heavily depredated by feral pigs. Other invasive animals and aquatic weeds dramatically alter freshwater habitats, with consequential impacts on freshwater turtles. Novel pathogens such as viruses have brought at least one species to the brink of extinction. Species that routinely migrate across land are impacted by structural simplification of habitat, reduction in availability of terrestrial refugia, fencing (including conservation fencing), and in some areas, by high levels of road mortality. We report on the listing process and challenges for listing freshwater turtles under the Australian Environment Protection and Biodiversity Conservation Act, summarize the state of knowledge relevant to listing decisions, identify the key threatening processes impacting turtles, and identify key knowledge gaps that impede the setting of priorities. We also focus on how to best incorporate First Nations Knowledge into decisions on listing and discuss opportunities to engage Indigenous communities in on-ground work to achieve conservation outcomes.     

Improved Visualization of Cell Nuclei in Unstained Cultured Cells

Nuclear morphology is useful in tissue culture studies in determining the presence and grade of transformed cells as well as in determining the heterogeneity of the cell population (Grogan el al. 1981, Hustin 1976, Siracky et al. 1978, Siracky 1979). The ratio of long and short nuclear axes provides a useful numerical expression of nuclear shape (Hustin 1976). Clear visualization of nuclei is critical for making the necessary measurements.     

Reversal or protection by light of the ethidium bromide induced petite mutation in yeast

Summary An intermediate in the ethidium bromide (EB) induced petite mutation pathway may be destabilized by daylight light to cause a reversion to the normal grande phenotype. Starved cells preincubated in the dark for up to 6 h with 100 g/ml EB could be reverted to grandes after one hour of light exposure, whereas similarly treated cells maintained in the dark expressed the petite mutation in more than 80 percent of the population. In addition, the production of petite mutants by EB in buffer could be prevented if cell suspensions were exposed to light immediately upon the addition of EB. Photoreversal of the EB-derived petite mutation in growing cells was less efficient presumably because the availability of an energy source caused a continuation of mutation events beyond the light revertible step to a non-reversible fixation of the mutation. Cells treated with EB in growth media at 4° C were more responsive to light protection and reversal of the mutation. This may be due to the cold inhibition of an enzyme which comes into play beyond the light sensitive step in the mutation pathway.     

1,25-dihydroxyvitamin D(3) stimulated protein kinase C phosphorylation of type VI adenylyl cyclase inhibits parathyroid hormone signal transduction in rat osteoblastic UMR 106-01 cells

1,25-Dihydroxyvitamin D(3) (1,25(OH)(2)D(3)) treatment of osteoblastic cells was shown previously to attenuate Parathyroid hormone (PTH) response by inhibiting adenylyl cyclase (AC) activity. In this study, we have investigated the mechanism by which 1,25(OH)(2)D(3) inhibits AC in rat osteoblastic UMR 106-01 cells. 1,25(OH)(2)D(3) treatment inhibited both PTH and forskolin-stimulated AC activity by 25%-50% within 12 min in a concentration-dependent manner suggesting a direct inhibition of the AC enzyme. Treatment with 25(OH)D(3) had no effect on basal or stimulated AC activity. We determined the profile of AC subtypes expressed in UMR cells and found AC VI to be the dominant subtype accounting for 50% of AC mRNA. Since AC VI can be inhibited by protein kinase C (PKC) phosphorylation, we examined 1,25(OH)(2)D(3) activation of various PKC isoforms. 1,25(OH)(2)D(3) increased the membrane translocation of PKC-betaI, -delta, and -zeta with a concomitant increase in PKC activity. The translocation of PKC-betaI and -delta was blocked by the PLC inhibitor U73122 whereas that of PKC-zeta was abolished by the PI-3 kinase inhibitor wortmannin. The attenuation of cAMP production by 1,25(OH)(2)D(3) was antagonized by the PKC inhibitors Go6850, calphostin C, and wortmannin, but not by a calmodulin kinase II (CaMKII) inhibitor. Treatment with 1,25(OH)(2)D(3) for 20 min increased AC VI phosphorylation by 10.8-fold and this was blocked partially by Go6850 and partially by wortmannin but was unaffected by CaMKII inhibitor. These results demonstrate that 1,25(OH)(2)D(3) activation of PKC isoforms leads to phosphorylation of AC VI and inhibition of PTH-activation of this pathway in osteoblasts.     

A central role for Bid in granzyme B-induced apoptosis

Granzyme B, a protease released from cytotoxic lymphocytes, has been proposed to induce target cell death by cleaving and activating the pro-apoptotic Bcl-2 family member Bid. It has also been proposed that granzyme B can induce target cell death by activating caspases directly, by cleaving caspase substrates, and/or by cleaving several non-caspase substrates. The relative importance of Bid in granzyme B-induced cell death has therefore remained unclear. Here we report that cells isolated from various tissues of Bid-deficient mice were resistant to granzyme B-induced cell death. Consistent with the proposed role of Bid in regulating mitochondrial outer membrane permeabilization, cytochrome c remained in the mitochondria of Bid-deficient cells treated with granzyme B. Unlike wild type cells, Bid-deficient cells survived and were then able to proliferate normally, demonstrating the critical role for Bid in mediating granzyme B-induced apoptosis.     

Life Cycle Assessment Software: Selection Can Impact Results

When software is used to facilitate life cycle assessments (LCAs), the implicit assumption is that the results obtained are not a function of the choice of software used. LCAs were done in both SimaPro and GaBi for simplified systems of creation and disposal of 1 kilogram each of four basic materials (aluminum, corrugated board, glass, and polyethylene terephthalate) to determine whether there were significant differences in the results. Data files and impact assessment methodologies (Impact 2002, ReCiPe, and TRACI 2) were ostensibly identical (although there were minor variations in the available ReCiPe version between the programs that were investigated). Differences in reported impacts of greater than 20% for at least one of the four materials were found for 9 of the 15 categories in Impact 2002+, 7 of the 18 categories in ReCiPe, and four of the nine categories in TRACI. In some cases, these differences resulted in changes in the relative rankings of the four materials. The causes of the differences for 14 combinations of materials and impact categories were examined by tracing the results back to the life cycle inventory data and the characterization factors in the life cycle impact assessment (LCIA) methods. In all cases examined, a difference in the characterization factors used by the two programs was the cause of the differing results. As a result, when these software programs are used to inform choices, the result can be different conclusions about relative environmental preference that are functions purely of the software implementation of LCIA methods, rather than of the underlying data.