Limonium hyblaeum (Plumbaginaceae), a cushion plant invading coastal southern Australia
Robert F. Parsons
- The Sicilian endemic herbaceous perennial plant Limonium hyblaeum (family Plumbaginaceae) is rapidly becoming a serious weed in South Australia and Victoria, where it invades saltmarshes and rocky coastal sites exposed to salt spray. It has small, light seeds that float and remain viable in sea water and which can also be dispersed readily by wind, animals and vehicles. It can form dense, extensive mats and buds sprouting from rhizomes allow encroachment into dense native vegetation. It seems certain to be apomictic and is readily able to become dominant. Forming dense, compact cushions which accumulate large amounts of fibrous peat, Limonium hyblaeum is the first cushion plant to become naturalized in Australia; the importance of the cushion habit as an adaptation to salt spray is under-appreciated. Some control measures for Limonium hyblaeum have begun in Victoria, but much remains to be done there and in the other southern Australian states; a ban on the sale of the species by nurseries is urgently required.
Replacement of Cakile edentula with Cakile maritima in New South Wales and on Lord Howe Island
- Two species of Cakile (Brassicaceae) have been introduced to Australia and the genus has been a common feature on the beaches of NSW for over 130 years; Cakile edentula has been present for at least 148 years (in NSW since about 1870), while Cakile maritima arrived approximately 114 years ago, (in NSW since about 1969). Collections at CANB and NSW confirm that since around 1970 plants more like Cakile maritima have almost entirely replaced Cakile edentula along the NSW coast. A similar phenomenon is reported for Lord Howe Island.
Upland wetlands in the Namoi Catchment: mapping distribution and disturbance classes of fens, bogs and lagoons
John T. Hunter
- To assist with planning and conservation strategies, mapping of wetlands above 700 m elevation across the Namoi Catchment (east of Tamworth) was undertaken. The number of hectares of each type within this high-elevation region, the area currently in conservation reserves and the status of these remnants was assessed. 1 001 wetlands were mapped and allocated to three wetland types (fens, bogs and lagoons) and six disturbance groups (based on agricultural clearing and presence of dams). Total wetlands cover was 4 490 ha, of which fens were the most common, followed by bogs and a single lagoon. The smallest wetland was 0.12 ha in size, the largest 113 ha and the average 5 ha. Only 10% of all wetlands were considered to be in near natural state with only 5.5% of all wetland area protected within conservation reserves.
Impact of broom, Cytisus scoparius (Fabaceae), in naturally treeless sub-alpine frost-hollow vegetation communities at the Barrington Tops, south-eastern Australia
John R. Hosking
- The exotic shrub Cytisus scoparius (L.) Link (family Fabaceae), known as broom, is having a major impact on native vegetation in naturally treeless sub-alpine frost-hollow areas (c. 32o 01’ 37” S, 151o 26’ 12” E’, 1440 m elevation) at the Barrington Tops, New South Wales, in south-eastern Australia. This vegetation is of limited extent and has significant biogeographical and ecological importance. Nine paired 10 m line transects were compared, with one of the pair in areas of almost 100% Cytisus scoparius and the other in adjacent areas without Cytisus scoparius. Results were compared with species recorded from this area in the 1930s. There are obvious differences in native vegetation in areas with and without Cytisus scoparius. On average there were 5.1 (range 2–10) species per 10 m in areas of almost 100% Cytisus scoparius cover and 17.0 (12–25) species per 10 m in areas adjacent to infested areas but without Cytisus scoparius. Other than Cytisus scoparius, the area surveyed had little in the way of exotic species and these were only present at low densities. Native species present in 2008 are similar to those recorded in the 1930s; there were no records of Cytisus scoparius in the area in the 1930s. The study suggests that control of Cytisus scoparius in naturally treeless areas at the Barrington Tops should be a priority to prevent a decline in the distribution and abundance of many plant species, many of which only occur in treeless areas of the Barrington Tops.
Adventures, hardship and a scientific legacy: Ludwig Leichhardt’s 1843 journey to Mt Royal in the Hunter Valley, NSW
- In January 1843, curiosity for natural history led a young German naturalist, Ludwig Leichhardt, to spend about three weeks exploring Mt Royal on the north of the Hunter Valley, about 70 km north west of Newcastle, New South Wales. This was a sidetrack on his journey from Newcastle, through the Hunter Valley and inland to Moreton Bay (Brisbane) and preceded the journeys for which he was to become famous; his 1844–45 overland journey from Moreton Bay to Port Essington (in Northern Territory) and his disappearance without trace in 1848 attempting to cross Australia. Using his Diary and herbarium records this paper brings together the chronological events of the 29 year old Leichhardt’s journey, the plant and animal species recorded, the specimens collected and his landscape descriptions and compares the 1843 landscape with the area today. Most of it is now in Mount Royal National Park, and part of the Gondwana Rainforest Reserves World Heritage Area. Using Mt Royal as an example of the richness of Leichhardt’s scientific legacy, we draw attention to the existence of a considerable number of Leichhardt’s plant specimens in herbaria in Sydney and Melbourne relating to his early collecting around Sydney and the little-known journey from Newcastle to Moreton Bay. Leichhardt’s visit to Mt Royal provides an insight into a gifted young naturalist coping with some of the hardships of nineteenth century botanical exploration, in a landscape which is easily recognizable and of which much is remarkably little changed since European settlement.
Survival of Casuarina cunninghamiana on a recovering sand-bed stream in the Wollombi Valley of coastal New South Wales
- The successful management and restoration of riparian corridors in Australia is currently hindered by our poor understanding of the links between hydrology, fluvial geomorphology and plant population dynamics. The aim of the current study was to determine the survival rates of Casuarina cunninghamiana subsp. cunninghamiana Miq. (family Casuarinaceae) on a sand-bed stream in the Wollombi Valley, a tributary of the Hunter River system, in coastal New South Wales (lat 33°02’S; long 151°10’E). A population planted on the banks of Dairy Arm in 1987, as part of river training works, was used to determine the long-term (24-year) survival rate. A bankfull flood in June 2011 provided an opportunity to examine the survival response of seedlings regenerating naturally within the channel. We found that 24% of the seedlings planted on the banks in 1987 had survived to adulthood. The bankfull flood significantly decreased (d.f. = 14; W= - 30; p = 0.0024) median seedling density within the channel from 12 to 2 individuals per 100 m2. Seedling survival varied with height, with seedlings > 15 cm more likely to survive the bankfull flood. The percentage of seedlings partially buried by sediment was significantly higher (d.f. = 14; W = 13; p = 0.016) after flood compared to before flood. Seedling density was positively correlated with the amount of bare ground prior to the flood (r = 0.61; p = 0.02), but this relationship was no longer significant after flood (r = 0.18; p = 0.53). 37% of the seedlings surveyed showed evidence of grazing. Our results confirm that hydrogeomorphic processes associated with a bankfull flood affect the survival of Casuarina cunninghamiana seedlings. The management implications of our findings are discussed in terms of riparian revegetation techniques and the geomorphic recovery of over-widened sand-bed streams.
Reassessment of the invasion history of two species of Cakile (Brassicaceae) in Australia
Roger D. Cousens
Peter K. Ades
Mohsen B. Mesgaran
- In this paper we revisit the invasion history of two species of Cakile in Australia. Cakile edentula subsp. edentula arrived in the mid 19th Century and spread into coastal strandline habitat from the southeast towards the west and to the north; Cakile maritima arrived in the late 19th Century and has replaced Cakile edentula over much of the range. While Cakile edentula is morphologically quite uniform, the great variation within Cakile maritima has confused field ecologists. Using herbarium records we update previous accounts of the spread of the species and report on field surveys that determined their current geographic overlap in Tasmania and in northern New South Wales/southern Queensland. We examine regional morphological variation within Cakile maritima using the national herbaria collections and variation within new population samples. We support previous interpretations that Cakile maritima has been introduced on more than one occasion from morphologically distinct races, resulting in regional variation within Australia and high variability within populations in the south-east. Western Australian populations appear distinct and probably did not initiate those in the east; we consider that eastern populations are likely to be a mix of Cakile maritima subsp. maritima from the Mediterranean and Cakile maritima subsp. integrifolia from Atlantic Europe. Although introgression from Cakile edentula into Cakile maritima cannot be discounted from our results, it is not required to explain the levels of variation in the latter species observed in Australia. Cakile maritima continues to spread southwards in Tasmania and northwards in NSW; in Queenland, a recent occurrence has proliferated in Moreton Bay, spreading slowly to the north but not appreciably southwards.
Endothelial Wnt/β-catenin signaling inhibits glioma angiogenesis and normalizes tumor blood vessels by inducing PDGF-B expression
Cathrin J. Czupalla
Makoto M. Taketo
Karl H. Plate
- Endothelial Wnt/β-catenin signaling is necessary for angiogenesis of the central nervous system and blood–brain barrier (BBB) differentiation, but its relevance for glioma vascularization is unknown. In this study, we show that doxycycline-dependent Wnt1 expression in subcutaneous and intracranial mouse glioma models induced endothelial Wnt/β-catenin signaling and led to diminished tumor growth, reduced vascular density, and normalized vessels with increased mural cell attachment. These findings were corroborated in GL261 glioma cells intracranially transplanted in mice expressing dominant-active β-catenin specifically in the endothelium. Enforced endothelial β-catenin signaling restored BBB characteristics, whereas inhibition by Dkk1 (Dickkopf-1) had opposing effects. By overactivating the Wnt pathway, we induced the Wnt/β-catenin–Dll4/Notch signaling cascade in tumor endothelia, blocking an angiogenic and favoring a quiescent vascular phenotype, indicated by induction of stalk cell genes. We show that β-catenin transcriptional activity directly regulated endothelial expression of platelet-derived growth factor B (PDGF-B), leading to mural cell recruitment thereby contributing to vascular quiescence and barrier function. We propose that reinforced Wnt/β-catenin signaling leads to inhibition of angiogenesis with normalized and less permeable vessels, which might prove to be a valuable therapeutic target for antiangiogenic and edema glioma therapy.
Context-induced creativity and the figurative use of taste terms
- For reasons of space, we only discussed one text in which the metaphors used seem to take their root in the context in which it has been written. One text is definitely not enough to make any definite claims on how widespread this phenomenon is. Given what we know about the two domains - FOOD and TASTE - one has reasons to believe that when speakers/conceptualisers(e.g. journalists) describe something which stands in some relation to both, they may intuitively be reaching for taste metaphors of the kind described above on the premise that this kind of ‘ornamentation’ will add some spice to what the addressee might otherwise consider a trivial (and boring) topic. At the same time, taste is only one among many properties a particular item of food or a substance (e.g. sugar) has. In consequence, one may well imagine contexts in which it is not its taste, but other properties (e.g. what Harbottle [1997:183] refers to as its 'pure white and deadly ’ image) that will make the conceptualiser reach for a particular linguistic or conceptual metaphor.
The Inhibition of Stat5 by a Peptide Aptamer Ligand Specific for the DNA Binding Domain Prevents Target Gene Transactivation and the Growth of Breast and Prostate Tumor Cells
- The signal transducer and activator of transcription Stat5 is transiently activated by growth factor and cytokine signals in normal cells, but its persistent activation has been observed in a wide range of human tumors. Aberrant Stat5 activity was initially observed in leukemias, but subsequently also found in carcinomas. We investigated the importance of Stat5 in human tumor cell lines. shRNA mediated downregulation of Stat5 revealed the dependence of prostate and breast cancer cells on the expression of this transcription factor. We extended these inhibition studies and derived a peptide aptamer (PA) ligand, which directly interacts with the DNA-binding domain of Stat5 in a yeast-two-hybrid screen. The Stat5 specific PA sequence is embedded in a thioredoxin (hTRX) scaffold protein. The resulting recombinant protein S5-DBD-PA was expressed in bacteria, purified and introduced into tumor cells by protein transduction. Alternatively, S5-DBD-PA was expressed in the tumor cells after infection with a S5-DBD-PA encoding gene transfer vector. Both strategies impaired the DNA-binding ability of Stat5, suppressed Stat5 dependent transactivation and caused its intracellular degradation. Our experiments describe a peptide based inhibitor of Stat5 protein activity which can serve as a lead for the development of a clinically useful compound for cancer treatment.