Black box and attics: Habitat selection and resource use by large threatened pythons in landscapes with contrasting human modification

Woodland and forest degradation, driven predominately by agricultural and pastoral production, is a crisis facing many species globally, in particular hollow‐dependent fauna. Large predatory species play important roles in both ecosystems and conservation strategies, but few studies have examined habitat selection of such species in intensively human‐modified landscapes. We quantified habitat selection and resource use by a large, top‐order and threatened snake (carpet python, Morelia spilota), between adjacent areas of high and low anthropogenic modification in inland Australia, a region that has undergone considerable alteration since European settlement. At the low‐impact site, snakes preferred tree hollows and a structurally complex understorey, whereas at the high‐impact site, snakes preferred homestead attics. Based on the decline of the species in this region, however, high‐impact landscapes may only support snakes when they are adjacent to low‐impact habitats. Invasive species comprised a large part of snake diets in both landscape types. Carpet pythons, with large home ranges and habitat requirements that overlap with many smaller threatened mammalian and avian fauna, are generally well liked and easily identifiable by rural landholders. Accordingly, they may play a key role in conservation strategies aimed at the protection of woodland and hollow‐dependent fauna in heavily modified landscapes of Australia's inland regions. However, invasive species, which tend to contribute to declines in native species inhabiting arid and semi‐arid Australia, are beneficial and important to pythons. Our study therefore highlights the diversity of effects that two major threats to biodiversity – habitat loss and invasive species – can have on different species within the same ecosystem.     

Environmental Manipulation to Avoid a Unique Predator: Drinking Hole Excavation in the Agile Wallaby, Macropus agilis

The simplest way of avoiding an ambush predator is to entirely avoid the habitat in which it hunts. However, this strategy requires that the prey species find alternative, risk‐free sources of essential resources. Herein we describe a novel strategy used by agile wallabies (Macropus agilis) to avoid saltwater crocodile (Crocodylus porosus) predation: the creation of risk‐free sites to obtain water. We studied the anti‐predator behaviour of agile wallabies for 3 yr during the dry season along the Daly River, Northern Territory, Australia. Wallabies excavated holes in the sand 0.5–18.0 m from the water's edge, and preferred to drink from these holes over drinking from the river. We determined a hierarchy of preferred drinking‐site options for the wallabies: non‐river sites: springs, puddles, excavated holes; and river sites: sites with cover, shallow water sites and deep water sites. Drinking holes were twice as far from the water's edge in a river stretch with high crocodile density (2/km) than those in a stretch with low crocodile density (0.08/km). However, site differences could also be explained by river bank morphology. Collectively, our findings indicate that agile wallabies excavate drinking holes to avoid crocodile predation. We contend that this behaviour represents environmental manipulation specifically to alter the risk associated with obtaining a key resource.     

Arylphthalazines: identification of a new phthalazine chemotype as inhibitors of VEGFR kinase

A novel class of 4-arylamino-phthalazin-1-yl-benzamides is described as inhibitors of vascular endothelial growth factor receptor II (VEGFR-2). Several compounds display potent VEGFR-2 inhibitory activity with an IC50 as low as 0.078 microM in an HTRF enzymatic assay. These compounds are relatively selective against a small kinase panel.     

Synthesis and structure-activity relationships of 1,2,4-triazoles as a novel class of potent tubulin polymerization inhibitors

A novel triazole-containing chemical series was shown to inhibit tubulin polymerization and cause cell cycle arrest in A431 cancer cells with EC(50) values in the single digit nanomolar range. Binding experiments demonstrated that representative active compounds of this class compete with colchicine for its binding site on tubulin. The syntheses and structure-activity relationship studies for the triazole derivatives are described herein.     

Glycoprotein 96 can chaperone both MHC class I- and class II-restricted epitopes for in vivo presentation, but selectively primes CD8+ T cell effector function

The ability of mature T lymphocytes to develop effector capacity after encounter with cognate Ag is generally dependent upon inflammatory signals associated with infection that induce dendritic cell activation/maturation. These inflammatory signals can derive directly from pathogens or can be expressed by host cells in response to infection. Heat shock proteins (HSPs) are a class of host-derived inflammatory mediators that perform the dual function of both chaperoning MHC class I-restricted epitopes into the cross-presentation pathway of DCs and inducing the activation/maturation of these DCs to allow priming of cognate CD8(+) T cell effector responses. Although the ability of HSPs to elicit effector CD8 cell responses has been well established, their potential to prime CD4 cell effector responses has been relatively unexplored. In the current study we compared the ability of the endoplasmic reticulum-resident HSP gp96 to prime CD4 vs CD8 cells using TCR transgenic adoptive transfer systems and soluble gp96-peptide complexes. As expected, gp96 facilitated the cross-presentation of a class I-restricted peptide and priming of effector function in cognate CD8 cells. Interestingly, gp96 also facilitated the in vivo presentation of a class II-restricted peptide; however, the resulting CD4 cell response did not involve the development of effector function. Taken together, these data suggest that gp96 is an inflammatory mediator that selectively primes CD8 cell effector function.     

Genome-wide association study of circulating estradiol, testosterone, and sex hormone-binding globulin in postmenopausal women

Genome-wide association studies (GWAS) have successfully identified common genetic variants that contribute to breast cancer risk. Discovering additional variants has become difficult, as power to detect variants of weaker effect with present sample sizes is limited. An alternative approach is to look for variants associated with quantitative traits that in turn affect disease risk. As exposure to high circulating estradiol and testosterone, and low sex hormone-binding globulin (SHBG) levels is implicated in breast cancer etiology, we conducted GWAS analyses of plasma estradiol, testosterone, and SHBG to identify new susceptibility alleles. Cancer Genetic Markers of Susceptibility (CGEMS) data from the Nurses' Health Study (NHS), and Sisters in Breast Cancer Screening data were used to carry out primary meta-analyses among ~1600 postmenopausal women who were not taking postmenopausal hormones at blood draw. We observed a genome-wide significant association between SHBG levels and rs727428 (joint β = -0.126; joint P = 2.09 × 10(-16)), downstream of the SHBG gene. No genome-wide significant associations were observed with estradiol or testosterone levels. Among variants that were suggestively associated with estradiol (P<10(-5)), several were located at the CYP19A1 gene locus. Overall results were similar in secondary meta-analyses that included ~900 NHS current postmenopausal hormone users. No variant associated with estradiol, testosterone, or SHBG at P<10(-5) was associated with postmenopausal breast cancer risk among CGEMS participants. Our results suggest that the small magnitude of difference in hormone levels associated with common genetic variants is likely insufficient to detectably contribute to breast cancer risk.     

Engineered bacterial outer membrane vesicles with enhanced functionality

We have engineered bacterial outer membrane vesicles (OMVs) with dramatically enhanced functionality by fusing several heterologous proteins to the vesicle-associated toxin ClyA of Escherichia coli. Similar to native unfused ClyA, chimeric ClyA fusion proteins were found localized in bacterial OMVs and retained activity of the fusion partners, demonstrating for the first time that ClyA can be used to co-localize fully functional heterologous proteins directly in bacterial OMVs. For instance, fusions of ClyA to the enzymes β-lactamase and organophosphorus hydrolase resulted in synthetic OMVs that were capable of hydrolyzing β-lactam antibiotics and paraoxon, respectively. Similarly, expression of an anti-digoxin single-chain Fv antibody fragment fused to the C terminus of ClyA resulted in designer “immuno-MVs” that could bind tightly and specifically to the antibody's cognate antigen. Finally, OMVs displaying green fluorescent protein fused to the C terminus of ClyA were highly fluorescent and, as a result of this new functionality, could be easily tracked during vesicle interaction with human epithelial cells. We expect that the relative plasticity exhibited by ClyA as a fusion partner should prove useful for: (i) further mechanistic studies to identify the vesiculation machinery that regulates OMV secretion and to map the intracellular routing of ClyA-containing OMVs during invasion of host cells; and (ii) biotechnology applications such as surface display of proteins and delivery of biologics.     

The use of historical environmental monitoring data to test predictions on cross-scale ecological responses to alterations in river flows

Determination of ecological responses to river flows is fundamental to understanding how flow-dependent ecosystems have been altered by regulation, water diversions and climate change, and how to effect river restoration. Knowledge of ecohydrological relationships can support water management and policy, but this is not always the case. Management rules have tended to be developed ahead of scientific knowledge. The lag between practice and knowledge could be addressed by using historical monitoring data on ecological responses to changes in flows to determine significant empirical ecohydrological relationships, as an adjunct to investigating responses prospectively. This possibility was explored in the Murray–Darling Basin, Australia. We assessed 359 data sets collected during monitoring programs across the basin. Of these, only 32 (9%) were considered useful, based on a match between the scale at which sampling was done and ecological responses are likely to occur, and used to test flow–ecology predictions for phytoplankton, macroinvertebrates, fishes, waterbirds, floodplain trees, basin-scale vegetation and estuarine biota. We found relationships between flow and ecological responses were likely to be more strongly supported for large, long-lived, widespread biota (waterbirds, basin-scale vegetation, native fishes), than for more narrowly distributed (e.g. estuarine fishes) or smaller, short-lived organisms (e.g. phytoplankton, macroinvertebrates). This pattern is attributed to a mismatch between the design of monitoring programs and the response time frames of individual biota and processes, and to the use of local river discharge as a primary predictor variable when, for many biotic groups, other predictors need to be considered.     

Arylphthalazines as potent,and orally bioavailable inhibitors of VEGFR-2

A series of arylphthalazine derivatives were synthesized and evaluated as antagonists of VEGF receptor II (VEGFR-2). IM-094482 57, which was prepared in two steps from commercially available starting materials, was found to be a potent inhibitor of VEGFR-2 in enzymatic, cellular and mitogenic assays (comparable activity to ZD-6474). Additionally, 57 inhibited the related receptor, VEGF receptor I (VEGFR-1), and showed excellent exposure when dosed orally to female CD-1 mice.